This fixes the problem introduced by commit 3bfacef412 (get rid of
special-casing the /sbin/loader on alpha): osf/1 ecoff binary segfaults
when binfmt_aout built as module. That happens because aout binary
handler gets on the top of the binfmt list due to late registration, and
kernel attempts to execute the binary without preparatory work that must
be done by binfmt_loader.
Fixed by changing the registration order of the default binfmt handlers
using list_add_tail() and introducing insert_binfmt() function which
places new handler on the top of the binfmt list. This might be generally
useful for installing arch-specific frontends for default handlers or just
for overriding them.
Signed-off-by: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Richard Henderson <rth@twiddle.net
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
write_lock(¤t->fs->lock) guarantees we can't wrongly miss
LSM_UNSAFE_SHARE, this is what we care about. Use rcu_read_lock()
instead of ->siglock to iterate over the sub-threads. We must see
all CLONE_THREAD|CLONE_FS threads which didn't pass exit_fs(), it
takes fs->lock too.
With or without this patch we can miss the freshly cloned thread
and set LSM_UNSAFE_SHARE, we don't care.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Roland McGrath <roland@redhat.com>
[ Fixed lock/unlock typo - Hugh ]
Acked-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
If do_execve() fails after check_unsafe_exec(), it clears fs->in_exec
unconditionally. This is wrong if we race with our sub-thread which
also does do_execve:
Two threads T1 and T2 and another process P, all share the same
->fs.
T1 starts do_execve(BAD_FILE). It calls check_unsafe_exec(), since
->fs is shared, we set LSM_UNSAFE but not ->in_exec.
P exits and decrements fs->users.
T2 starts do_execve(), calls check_unsafe_exec(), now ->fs is not
shared, we set fs->in_exec.
T1 continues, open_exec(BAD_FILE) fails, we clear ->in_exec and
return to the user-space.
T1 does clone(CLONE_FS /* without CLONE_THREAD */).
T2 continues without LSM_UNSAFE_SHARE while ->fs is shared with
another process.
Change check_unsafe_exec() to return res = 1 if we set ->in_exec, and change
do_execve() to clear ->in_exec depending on res.
When do_execve() suceeds, it is safe to clear ->in_exec unconditionally.
It can be set only if we don't share ->fs with another process, and since
we already killed all sub-threads either ->in_exec == 0 or we are the
only user of this ->fs.
Also, we do not need fs->lock to clear fs->in_exec.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Roland McGrath <roland@redhat.com>
Acked-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Similar to the mmap data stream, add one that tracks the task COMM field,
so that the userspace reporting knows what to call a task.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
LKML-Reference: <20090408130409.127422406@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Merge reason: we have gathered quite a few conflicts, need to merge upstream
Conflicts:
arch/powerpc/kernel/Makefile
arch/x86/ia32/ia32entry.S
arch/x86/include/asm/hardirq.h
arch/x86/include/asm/unistd_32.h
arch/x86/include/asm/unistd_64.h
arch/x86/kernel/cpu/common.c
arch/x86/kernel/irq.c
arch/x86/kernel/syscall_table_32.S
arch/x86/mm/iomap_32.c
include/linux/sched.h
kernel/Makefile
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Don't pull it in sched.h; very few files actually need it and those
can include directly. sched.h itself only needs forward declaration
of struct fs_struct;
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* all changes of current->fs are done under task_lock and write_lock of
old fs->lock
* refcount is not atomic anymore (same protection)
* its decrements are done when removing reference from current; at the
same time we decide whether to free it.
* put_fs_struct() is gone
* new field - ->in_exec. Set by check_unsafe_exec() if we are trying to do
execve() and only subthreads share fs_struct. Cleared when finishing exec
(success and failure alike). Makes CLONE_FS fail with -EAGAIN if set.
* check_unsafe_exec() may fail with -EAGAIN if another execve() from subthread
is in progress.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Joe Malicki reports that setuid sometimes doesn't: very rarely,
a setuid root program does not get root euid; and, by the way,
they have a health check running lsof every few minutes.
Right, check_unsafe_exec() notes whether the files_struct is being
shared by more threads than will get killed by the exec, and if so
sets LSM_UNSAFE_SHARE to make bprm_set_creds() careful about euid.
But /proc/<pid>/fd and /proc/<pid>/fdinfo lookups make transient
use of get_files_struct(), which also raises that sharing count.
There's a rather simple fix for this: exec's check on files->count
has been redundant ever since 2.6.1 made it unshare_files() (except
while compat_do_execve() omitted to do so) - just remove that check.
[Note to -stable: this patch will not apply before 2.6.29: earlier
releases should just remove the files->count line from unsafe_exec().]
Reported-by: Joe Malicki <jmalicki@metacarta.com>
Narrowed-down-by: Michael Itz <mitz@metacarta.com>
Tested-by: Joe Malicki <jmalicki@metacarta.com>
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch allows LSM modules to determine whether current process is in an
execve operation or not so that they can behave differently while an execve
operation is in progress.
This patch is needed by TOMOYO. Please see another patch titled "LSM adapter
functions." for backgrounds.
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
The patch:
commit a6f76f23d2
CRED: Make execve() take advantage of copy-on-write credentials
moved the place in which the 'safeness' of a SUID/SGID exec was performed to
before de_thread() was called. This means that LSM_UNSAFE_SHARE is now
calculated incorrectly. This flag is set if any of the usage counts for
fs_struct, files_struct and sighand_struct are greater than 1 at the time the
determination is made. All of which are true for threads created by the
pthread library.
However, since we wish to make the security calculation before irrevocably
damaging the process so that we can return it an error code in the case where
we decide we want to reject the exec request on this basis, we have to make the
determination before calling de_thread().
So, instead, we count up the number of threads (CLONE_THREAD) that are sharing
our fs_struct (CLONE_FS), files_struct (CLONE_FILES) and sighand_structs
(CLONE_SIGHAND/CLONE_THREAD) with us. These will be killed by de_thread() and
so can be discounted by check_unsafe_exec().
We do have to be careful because CLONE_THREAD does not imply FS or FILES.
We _assume_ that there will be no extra references to these structs held by the
threads we're going to kill.
This can be tested with the attached pair of programs. Build the two programs
using the Makefile supplied, and run ./test1 as a non-root user. If
successful, you should see something like:
[dhowells@andromeda tmp]$ ./test1
--TEST1--
uid=4043, euid=4043 suid=4043
exec ./test2
--TEST2--
uid=4043, euid=0 suid=0
SUCCESS - Correct effective user ID
and if unsuccessful, something like:
[dhowells@andromeda tmp]$ ./test1
--TEST1--
uid=4043, euid=4043 suid=4043
exec ./test2
--TEST2--
uid=4043, euid=4043 suid=4043
ERROR - Incorrect effective user ID!
The non-root user ID you see will depend on the user you run as.
[test1.c]
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <pthread.h>
static void *thread_func(void *arg)
{
while (1) {}
}
int main(int argc, char **argv)
{
pthread_t tid;
uid_t uid, euid, suid;
printf("--TEST1--\n");
getresuid(&uid, &euid, &suid);
printf("uid=%d, euid=%d suid=%d\n", uid, euid, suid);
if (pthread_create(&tid, NULL, thread_func, NULL) < 0) {
perror("pthread_create");
exit(1);
}
printf("exec ./test2\n");
execlp("./test2", "test2", NULL);
perror("./test2");
_exit(1);
}
[test2.c]
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
int main(int argc, char **argv)
{
uid_t uid, euid, suid;
getresuid(&uid, &euid, &suid);
printf("--TEST2--\n");
printf("uid=%d, euid=%d suid=%d\n", uid, euid, suid);
if (euid != 0) {
fprintf(stderr, "ERROR - Incorrect effective user ID!\n");
exit(1);
}
printf("SUCCESS - Correct effective user ID\n");
exit(0);
}
[Makefile]
CFLAGS = -D_GNU_SOURCE -Wall -Werror -Wunused
all: test1 test2
test1: test1.c
gcc $(CFLAGS) -o test1 test1.c -lpthread
test2: test2.c
gcc $(CFLAGS) -o test2 test2.c
sudo chown root.root test2
sudo chmod +s test2
Reported-by: David Smith <dsmith@redhat.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: David Smith <dsmith@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
This patch replaces the generic integrity hooks, for which IMA registered
itself, with IMA integrity hooks in the appropriate places directly
in the fs directory.
Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
No one cares do_coredump()'s return value, and also it seems that it
is also not necessary. So make it void.
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: WANG Cong <wangcong@zeuux.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Untangle the error unwinding in this function, saving a test of local
variable `vma'.
Signed-off-by: Luiz Fernando N. Capitulino <lcapitulino@mandriva.com.br>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
sys_execve and sys_uselib do not call into fsnotify so inotify does not get
open events for these types of syscalls. This patch simply makes the
requisite fsnotify calls.
Signed-off-by: Eric Paris <eparis@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
... just make it a binfmt handler like #! one.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
With all the nameidata removal there's no point anymore for this helper.
Of the three callers left two will go away with the next lookup series
anyway.
Also add proper kerneldoc to inode_permission as this is the main
permission check routine now.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
hrtimers: fix warning in kernel/hrtimer.c
x86: make sure we really have an hpet mapping before using it
x86: enable HPET on Fujitsu u9200
linux/timex.h: cleanup for userspace
posix-timers: simplify de_thread()->exit_itimers() path
posix-timers: check ->it_signal instead of ->it_pid to validate the timer
posix-timers: use "struct pid*" instead of "struct task_struct*"
nohz: suppress needless timer reprogramming
clocksource, acpi_pm.c: put acpi_pm_read_slow() under CONFIG_PCI
nohz: no softirq pending warnings for offline cpus
hrtimer: removing all ur callback modes, fix
hrtimer: removing all ur callback modes, fix hotplug
hrtimer: removing all ur callback modes
x86: correct link to HPET timer specification
rtc-cmos: export second NVRAM bank
Fixed up conflicts in sound/drivers/pcsp/pcsp.c and sound/core/hrtimer.c
manually.
Pavel Machek pointed out that performance counters should be flushed
when crossing protection domains on setuid execution.
Reported-by: Pavel Machek <pavel@suse.cz>
Acked-by: Pavel Machek <pavel@suse.cz>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: simplify code
de_thread() postpones release_task(leader) until after exit_itimers().
This was needed because !SIGEV_THREAD_ID timers could use ->group_leader
without get_task_struct(). With the recent changes we can release the
leader earlier and simplify the code.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
The patch 6341c39 "tracehook: exec" introduced a small regression in
2.6.27 regarding binfmt_misc exec event reporting. Since the reporting
is now done in the common search_binary_handler() function, an exec
of a misc binary will result in two (or possibly multiple) exec events
being reported, instead of just a single one, because the misc handler
contains a recursive call to search_binary_handler.
To add to the confusion, if PTRACE_O_TRACEEXEC is not active, the multiple
SIGTRAP signals will in fact cause only a single ptrace intercept, as the
signals are not queued. However, if PTRACE_O_TRACEEXEC is on, the debugger
will actually see multiple ptrace intercepts (PTRACE_EVENT_EXEC).
The test program included below demonstrates the problem.
This change fixes the bug by calling tracehook_report_exec() only in the
outermost search_binary_handler() call (bprm->recursion_depth == 0).
The additional change to restore bprm->recursion_depth after each binfmt
load_binary call is actually superfluous for this bug, since we test the
value saved on entry to search_binary_handler(). But it keeps the use of
of the depth count to its most obvious expected meaning. Depending on what
binfmt handlers do in certain cases, there could have been false-positive
tests for recursion limits before this change.
/* Test program using PTRACE_O_TRACEEXEC.
This forks and exec's the first argument with the rest of the arguments,
while ptrace'ing. It expects to see one PTRACE_EVENT_EXEC stop and
then a successful exit, with no other signals or events in between.
Test for kernel doing two PTRACE_EVENT_EXEC stops for a binfmt_misc exec:
$ gcc -g traceexec.c -o traceexec
$ sudo sh -c 'echo :test:M::foobar::/bin/cat: > /proc/sys/fs/binfmt_misc/register'
$ echo 'foobar test' > ./foobar
$ chmod +x ./foobar
$ ./traceexec ./foobar; echo $?
==> good <==
foobar test
0
$
==> bad <==
foobar test
unexpected status 0x4057f != 0
3
$
*/
#include <stdio.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <sys/ptrace.h>
#include <unistd.h>
#include <signal.h>
#include <stdlib.h>
static void
wait_for (pid_t child, int expect)
{
int status;
pid_t p = wait (&status);
if (p != child)
{
perror ("wait");
exit (2);
}
if (status != expect)
{
fprintf (stderr, "unexpected status %#x != %#x\n", status, expect);
exit (3);
}
}
int
main (int argc, char **argv)
{
pid_t child = fork ();
if (child < 0)
{
perror ("fork");
return 127;
}
else if (child == 0)
{
ptrace (PTRACE_TRACEME);
raise (SIGUSR1);
execv (argv[1], &argv[1]);
perror ("execve");
_exit (127);
}
wait_for (child, W_STOPCODE (SIGUSR1));
if (ptrace (PTRACE_SETOPTIONS, child,
0L, (void *) (long) PTRACE_O_TRACEEXEC) != 0)
{
perror ("PTRACE_SETOPTIONS");
return 4;
}
if (ptrace (PTRACE_CONT, child, 0L, 0L) != 0)
{
perror ("PTRACE_CONT");
return 5;
}
wait_for (child, W_STOPCODE (SIGTRAP | (PTRACE_EVENT_EXEC << 8)));
if (ptrace (PTRACE_CONT, child, 0L, 0L) != 0)
{
perror ("PTRACE_CONT");
return 6;
}
wait_for (child, W_EXITCODE (0, 0));
return 0;
}
Reported-by: Arnd Bergmann <arnd@arndb.de>
CC: Ulrich Weigand <ulrich.weigand@de.ibm.com>
Signed-off-by: Roland McGrath <roland@redhat.com>
Make execve() take advantage of copy-on-write credentials, allowing it to set
up the credentials in advance, and then commit the whole lot after the point
of no return.
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
The credential bits from struct linux_binprm are, for the most part,
replaced with a single credentials pointer (bprm->cred). This means that
all the creds can be calculated in advance and then applied at the point
of no return with no possibility of failure.
I would like to replace bprm->cap_effective with:
cap_isclear(bprm->cap_effective)
but this seems impossible due to special behaviour for processes of pid 1
(they always retain their parent's capability masks where normally they'd
be changed - see cap_bprm_set_creds()).
The following sequence of events now happens:
(a) At the start of do_execve, the current task's cred_exec_mutex is
locked to prevent PTRACE_ATTACH from obsoleting the calculation of
creds that we make.
(a) prepare_exec_creds() is then called to make a copy of the current
task's credentials and prepare it. This copy is then assigned to
bprm->cred.
This renders security_bprm_alloc() and security_bprm_free()
unnecessary, and so they've been removed.
(b) The determination of unsafe execution is now performed immediately
after (a) rather than later on in the code. The result is stored in
bprm->unsafe for future reference.
(c) prepare_binprm() is called, possibly multiple times.
(i) This applies the result of set[ug]id binaries to the new creds
attached to bprm->cred. Personality bit clearance is recorded,
but now deferred on the basis that the exec procedure may yet
fail.
(ii) This then calls the new security_bprm_set_creds(). This should
calculate the new LSM and capability credentials into *bprm->cred.
This folds together security_bprm_set() and parts of
security_bprm_apply_creds() (these two have been removed).
Anything that might fail must be done at this point.
(iii) bprm->cred_prepared is set to 1.
bprm->cred_prepared is 0 on the first pass of the security
calculations, and 1 on all subsequent passes. This allows SELinux
in (ii) to base its calculations only on the initial script and
not on the interpreter.
(d) flush_old_exec() is called to commit the task to execution. This
performs the following steps with regard to credentials:
(i) Clear pdeath_signal and set dumpable on certain circumstances that
may not be covered by commit_creds().
(ii) Clear any bits in current->personality that were deferred from
(c.i).
(e) install_exec_creds() [compute_creds() as was] is called to install the
new credentials. This performs the following steps with regard to
credentials:
(i) Calls security_bprm_committing_creds() to apply any security
requirements, such as flushing unauthorised files in SELinux, that
must be done before the credentials are changed.
This is made up of bits of security_bprm_apply_creds() and
security_bprm_post_apply_creds(), both of which have been removed.
This function is not allowed to fail; anything that might fail
must have been done in (c.ii).
(ii) Calls commit_creds() to apply the new credentials in a single
assignment (more or less). Possibly pdeath_signal and dumpable
should be part of struct creds.
(iii) Unlocks the task's cred_replace_mutex, thus allowing
PTRACE_ATTACH to take place.
(iv) Clears The bprm->cred pointer as the credentials it was holding
are now immutable.
(v) Calls security_bprm_committed_creds() to apply any security
alterations that must be done after the creds have been changed.
SELinux uses this to flush signals and signal handlers.
(f) If an error occurs before (d.i), bprm_free() will call abort_creds()
to destroy the proposed new credentials and will then unlock
cred_replace_mutex. No changes to the credentials will have been
made.
(2) LSM interface.
A number of functions have been changed, added or removed:
(*) security_bprm_alloc(), ->bprm_alloc_security()
(*) security_bprm_free(), ->bprm_free_security()
Removed in favour of preparing new credentials and modifying those.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
(*) security_bprm_post_apply_creds(), ->bprm_post_apply_creds()
Removed; split between security_bprm_set_creds(),
security_bprm_committing_creds() and security_bprm_committed_creds().
(*) security_bprm_set(), ->bprm_set_security()
Removed; folded into security_bprm_set_creds().
(*) security_bprm_set_creds(), ->bprm_set_creds()
New. The new credentials in bprm->creds should be checked and set up
as appropriate. bprm->cred_prepared is 0 on the first call, 1 on the
second and subsequent calls.
(*) security_bprm_committing_creds(), ->bprm_committing_creds()
(*) security_bprm_committed_creds(), ->bprm_committed_creds()
New. Apply the security effects of the new credentials. This
includes closing unauthorised files in SELinux. This function may not
fail. When the former is called, the creds haven't yet been applied
to the process; when the latter is called, they have.
The former may access bprm->cred, the latter may not.
(3) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) The bprm_security_struct struct has been removed in favour of using
the credentials-under-construction approach.
(c) flush_unauthorized_files() now takes a cred pointer and passes it on
to inode_has_perm(), file_has_perm() and dentry_open().
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
Inaugurate copy-on-write credentials management. This uses RCU to manage the
credentials pointer in the task_struct with respect to accesses by other tasks.
A process may only modify its own credentials, and so does not need locking to
access or modify its own credentials.
A mutex (cred_replace_mutex) is added to the task_struct to control the effect
of PTRACE_ATTACHED on credential calculations, particularly with respect to
execve().
With this patch, the contents of an active credentials struct may not be
changed directly; rather a new set of credentials must be prepared, modified
and committed using something like the following sequence of events:
struct cred *new = prepare_creds();
int ret = blah(new);
if (ret < 0) {
abort_creds(new);
return ret;
}
return commit_creds(new);
There are some exceptions to this rule: the keyrings pointed to by the active
credentials may be instantiated - keyrings violate the COW rule as managing
COW keyrings is tricky, given that it is possible for a task to directly alter
the keys in a keyring in use by another task.
To help enforce this, various pointers to sets of credentials, such as those in
the task_struct, are declared const. The purpose of this is compile-time
discouragement of altering credentials through those pointers. Once a set of
credentials has been made public through one of these pointers, it may not be
modified, except under special circumstances:
(1) Its reference count may incremented and decremented.
(2) The keyrings to which it points may be modified, but not replaced.
The only safe way to modify anything else is to create a replacement and commit
using the functions described in Documentation/credentials.txt (which will be
added by a later patch).
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
This now prepares and commits credentials in various places in the
security code rather than altering the current creds directly.
(2) Temporary credential overrides.
do_coredump() and sys_faccessat() now prepare their own credentials and
temporarily override the ones currently on the acting thread, whilst
preventing interference from other threads by holding cred_replace_mutex
on the thread being dumped.
This will be replaced in a future patch by something that hands down the
credentials directly to the functions being called, rather than altering
the task's objective credentials.
(3) LSM interface.
A number of functions have been changed, added or removed:
(*) security_capset_check(), ->capset_check()
(*) security_capset_set(), ->capset_set()
Removed in favour of security_capset().
(*) security_capset(), ->capset()
New. This is passed a pointer to the new creds, a pointer to the old
creds and the proposed capability sets. It should fill in the new
creds or return an error. All pointers, barring the pointer to the
new creds, are now const.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
Changed; now returns a value, which will cause the process to be
killed if it's an error.
(*) security_task_alloc(), ->task_alloc_security()
Removed in favour of security_prepare_creds().
(*) security_cred_free(), ->cred_free()
New. Free security data attached to cred->security.
(*) security_prepare_creds(), ->cred_prepare()
New. Duplicate any security data attached to cred->security.
(*) security_commit_creds(), ->cred_commit()
New. Apply any security effects for the upcoming installation of new
security by commit_creds().
(*) security_task_post_setuid(), ->task_post_setuid()
Removed in favour of security_task_fix_setuid().
(*) security_task_fix_setuid(), ->task_fix_setuid()
Fix up the proposed new credentials for setuid(). This is used by
cap_set_fix_setuid() to implicitly adjust capabilities in line with
setuid() changes. Changes are made to the new credentials, rather
than the task itself as in security_task_post_setuid().
(*) security_task_reparent_to_init(), ->task_reparent_to_init()
Removed. Instead the task being reparented to init is referred
directly to init's credentials.
NOTE! This results in the loss of some state: SELinux's osid no
longer records the sid of the thread that forked it.
(*) security_key_alloc(), ->key_alloc()
(*) security_key_permission(), ->key_permission()
Changed. These now take cred pointers rather than task pointers to
refer to the security context.
(4) sys_capset().
This has been simplified and uses less locking. The LSM functions it
calls have been merged.
(5) reparent_to_kthreadd().
This gives the current thread the same credentials as init by simply using
commit_thread() to point that way.
(6) __sigqueue_alloc() and switch_uid()
__sigqueue_alloc() can't stop the target task from changing its creds
beneath it, so this function gets a reference to the currently applicable
user_struct which it then passes into the sigqueue struct it returns if
successful.
switch_uid() is now called from commit_creds(), and possibly should be
folded into that. commit_creds() should take care of protecting
__sigqueue_alloc().
(7) [sg]et[ug]id() and co and [sg]et_current_groups.
The set functions now all use prepare_creds(), commit_creds() and
abort_creds() to build and check a new set of credentials before applying
it.
security_task_set[ug]id() is called inside the prepared section. This
guarantees that nothing else will affect the creds until we've finished.
The calling of set_dumpable() has been moved into commit_creds().
Much of the functionality of set_user() has been moved into
commit_creds().
The get functions all simply access the data directly.
(8) security_task_prctl() and cap_task_prctl().
security_task_prctl() has been modified to return -ENOSYS if it doesn't
want to handle a function, or otherwise return the return value directly
rather than through an argument.
Additionally, cap_task_prctl() now prepares a new set of credentials, even
if it doesn't end up using it.
(9) Keyrings.
A number of changes have been made to the keyrings code:
(a) switch_uid_keyring(), copy_keys(), exit_keys() and suid_keys() have
all been dropped and built in to the credentials functions directly.
They may want separating out again later.
(b) key_alloc() and search_process_keyrings() now take a cred pointer
rather than a task pointer to specify the security context.
(c) copy_creds() gives a new thread within the same thread group a new
thread keyring if its parent had one, otherwise it discards the thread
keyring.
(d) The authorisation key now points directly to the credentials to extend
the search into rather pointing to the task that carries them.
(e) Installing thread, process or session keyrings causes a new set of
credentials to be created, even though it's not strictly necessary for
process or session keyrings (they're shared).
(10) Usermode helper.
The usermode helper code now carries a cred struct pointer in its
subprocess_info struct instead of a new session keyring pointer. This set
of credentials is derived from init_cred and installed on the new process
after it has been cloned.
call_usermodehelper_setup() allocates the new credentials and
call_usermodehelper_freeinfo() discards them if they haven't been used. A
special cred function (prepare_usermodeinfo_creds()) is provided
specifically for call_usermodehelper_setup() to call.
call_usermodehelper_setkeys() adjusts the credentials to sport the
supplied keyring as the new session keyring.
(11) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) selinux_setprocattr() no longer does its check for whether the
current ptracer can access processes with the new SID inside the lock
that covers getting the ptracer's SID. Whilst this lock ensures that
the check is done with the ptracer pinned, the result is only valid
until the lock is released, so there's no point doing it inside the
lock.
(12) is_single_threaded().
This function has been extracted from selinux_setprocattr() and put into
a file of its own in the lib/ directory as join_session_keyring() now
wants to use it too.
The code in SELinux just checked to see whether a task shared mm_structs
with other tasks (CLONE_VM), but that isn't good enough. We really want
to know if they're part of the same thread group (CLONE_THREAD).
(13) nfsd.
The NFS server daemon now has to use the COW credentials to set the
credentials it is going to use. It really needs to pass the credentials
down to the functions it calls, but it can't do that until other patches
in this series have been applied.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: James Morris <jmorris@namei.org>
Wrap current->cred and a few other accessors to hide their actual
implementation.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
Separate the task security context from task_struct. At this point, the
security data is temporarily embedded in the task_struct with two pointers
pointing to it.
Note that the Alpha arch is altered as it refers to (E)UID and (E)GID in
entry.S via asm-offsets.
With comment fixes Signed-off-by: Marc Dionne <marc.c.dionne@gmail.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
Wrap access to task credentials so that they can be separated more easily from
the task_struct during the introduction of COW creds.
Change most current->(|e|s|fs)[ug]id to current_(|e|s|fs)[ug]id().
Change some task->e?[ug]id to task_e?[ug]id(). In some places it makes more
sense to use RCU directly rather than a convenient wrapper; these will be
addressed by later patches.
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: James Morris <jmorris@namei.org>
If the coredumping is multi-threaded, format_corename() appends .%pid to
the corename. This was needed before the proper multi-thread core dump
support, now all the threads in the mm go into a single unified core file.
Remove this special case, it is not even documented and we have "%p"
and core_uses_pid.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Michael Kerrisk <mtk.manpages@googlemail.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Roland McGrath <roland@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: La Monte Yarroll <piggy@laurelnetworks.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-for-linus:
module: remove CONFIG_KMOD in comment after #endif
remove CONFIG_KMOD from fs
remove CONFIG_KMOD from drivers
Manually fix conflict due to include cleanups in drivers/md/md.c
de_thread() checks if the old leader was the ->child_reaper, this is not
possible any longer. With the previous patch ->group_leader itself will
change ->child_reaper on exit.
Henceforth find_new_reaper() is the only function (apart from
initialization) which plays with ->child_reaper.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Acked-by: Pavel Emelyanov <xemul@openvz.org>
Acked-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This change is Alpha-specific. It adds field 'taso' into struct
linux_binprm to remember if the application is TASO. Previously, field
sh_bang was used for this purpose.
Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
With MAX_ARG_STRINGS set to 0x7FFFFFFF, and being passed to 'count()' and
compat_count(), it would appear that the current max bounds check of
fs/exec.c:394:
if(++i > max)
return -E2BIG;
would never trigger. Since 'i' is of type int, so values would wrap and the
function would continue looping.
Simple fix seems to be chaning ++i to i++ and checking for '>='.
Signed-off-by: Jason Baron <jbaron@redhat.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: "Ollie Wild" <aaw@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Just always compile the code when the kernel is modular.
Convert load_nls to use try_then_request_module to tidy
up the code.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
There's a race between mm->owner assignment and swapoff, more easily
seen when task slab poisoning is turned on. The condition occurs when
try_to_unuse() runs in parallel with an exiting task. A similar race
can occur with callers of get_task_mm(), such as /proc/<pid>/<mmstats>
or ptrace or page migration.
CPU0 CPU1
try_to_unuse
looks at mm = task0->mm
increments mm->mm_users
task 0 exits
mm->owner needs to be updated, but no
new owner is found (mm_users > 1, but
no other task has task->mm = task0->mm)
mm_update_next_owner() leaves
mmput(mm) decrements mm->mm_users
task0 freed
dereferencing mm->owner fails
The fix is to notify the subsystem via mm_owner_changed callback(),
if no new owner is found, by specifying the new task as NULL.
Jiri Slaby:
mm->owner was set to NULL prior to calling cgroup_mm_owner_callbacks(), but
must be set after that, so as not to pass NULL as old owner causing oops.
Daisuke Nishimura:
mm_update_next_owner() may set mm->owner to NULL, but mem_cgroup_from_task()
and its callers need to take account of this situation to avoid oops.
Hugh Dickins:
Lockdep warning and hang below exec_mmap() when testing these patches.
exit_mm() up_reads mmap_sem before calling mm_update_next_owner(),
so exec_mmap() now needs to do the same. And with that repositioning,
there's now no point in mm_need_new_owner() allowing for NULL mm.
Reported-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix compilation errors on avr32 and without CONFIG_SWAP, introduced by
ba92a43dba ("exec: remove some includes")
In file included from include/asm/tlb.h:24,
from fs/exec.c:55:
include/asm-generic/tlb.h: In function 'tlb_flush_mmu':
include/asm-generic/tlb.h:76: error: implicit declaration of function 'release_pages'
include/asm-generic/tlb.h: In function 'tlb_remove_page':
include/asm-generic/tlb.h:105: error: implicit declaration of function 'page_cache_release'
make[1]: *** [fs/exec.o] Error 1
This straightforward part-revert is nobody's favourite patch to address
the underlying tlb.h needs swap.h needs pagemap.h (but sparc won't like
that) mess; but appropriate to fix the build now before any overhaul.
Reported-by: Yoichi Yuasa <yoichi_yuasa@tripeaks.co.jp>
Reported-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com>
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Tested-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
On Mon, May 19, 2008 at 12:01:49AM +0200, Marcin Slusarz wrote:
> open_exec is needlessly indented, calls ERR_PTR with 0 argument
> (which is not valid errno) and jumps into middle of function
> just to return value.
> So clean it up a bit.
Still looks rather messy. See below for a better version.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This moves all the ptrace hooks related to exec into tracehook.h inlines.
This also lifts the calls for tracing out of the binfmt load_binary hooks
into search_binary_handler() after it calls into the binfmt module. This
change has no effect, since all the binfmt modules' load_binary functions
did the call at the end on success, and now search_binary_handler() does
it immediately after return if successful. We consolidate the repeated
code, and binfmt modules no longer need to import ptrace_notify().
Signed-off-by: Roland McGrath <roland@redhat.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Reviewed-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
I don't understand why the multi-thread coredump implies the core_uses_pid
behaviour, but we shouldn't use mm->mm_users for that. This counter can
be incremented by get_task_mm(). Use the valued returned by
coredump_wait() instead.
Also, remove the "const char *pattern" argument, format_corename() can use
core_pattern directly.
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Now that we have core_state->dumper list we can use it to wake up the
sub-threads waiting for the coredump completion.
This uglifies the code and .text grows by 47 bytes, but otoh mm_struct
lessens by sizeof(struct completion). Also, with this change we can
decouple exit_mm() from the coredumping code.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
binfmt->core_dump() has to iterate over the all threads in system in order
to find the coredumping threads and construct the list using the
GFP_ATOMIC allocations.
With this patch each thread allocates the list node on exit_mm()'s stack and
adds itself to the list.
This allows us to do further changes:
- simplify ->core_dump()
- change exit_mm() to clear ->mm first, then wait for ->core_done.
this makes the coredumping process visible to oom_kill
- kill mm->core_done
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Acked-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Move the "struct core_state core_state" from coredump_wait() to
do_coredump(), this makes mm->core_state visible to binfmt->core_dump().
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Acked-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Turn core_state->nr_threads into atomic_t and kill now unneeded
down_write(&mm->mmap_sem) in exit_mm().
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Change zap_process() to return int instead of incrementing
mm->core_state->nr_threads directly. Change zap_threads() to set
mm->core_state only on success.
This patch restores the original size of .text, and more importantly now
->nr_threads is used in two places only.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Move mm->core_waiters into "struct core_state" allocated on stack. This
shrinks mm_struct a little bit and allows further changes.
This patch mostly does s/core_waiters/core_state. The only essential
change is that coredump_wait() must clear mm->core_state before return.
The coredump_wait()'s path is uglified and .text grows by 30 bytes, this
is fixed by the next patch.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm->core_startup_done points to "struct completion startup_done" allocated
on the coredump_wait()'s stack. Introduce the new structure, core_state,
which holds this "struct completion". This way we can add more info
visible to the threads participating in coredump without enlarging
mm_struct.
No changes in affected .o files.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The main loop in zap_threads() must skip kthreads which may use the same
mm. Otherwise we "kill" this thread erroneously (for example, it can not
fork or exec after that), and the coredumping task stucks in the
TASK_UNINTERRUPTIBLE state forever because of the wrong ->core_waiters
count.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Introduce the new PF_KTHREAD flag to mark the kernel threads. It is set
by INIT_TASK() and copied to the forked childs (we could set it in
kthreadd() along with PF_NOFREEZE instead).
daemonize() was changed as well. In that case testing of PF_KTHREAD is
racy, but daemonize() is hopeless anyway.
This flag is cleared in do_execve(), before search_binary_handler().
Probably not the best place, we can do this in exec_mmap() or in
start_thread(), or clear it along with PF_FORKNOEXEC. But I think this
doesn't matter in practice, and if do_execve() fails kthread should die
soon.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
No changes in fs/exec.o
The for_each_process() loop in zap_threads() is very subtle, it is not
clear why we don't race with fork/exit/exec. Add the fat comment.
Also, change the code to use while_each_thread().
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Acked-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
fs/exec.c used to need mman.h pagemap.h swap.h and rmap.h when it did
mm-ish stuff in install_arg_page(); but no need for them after 2.6.22.
[akpm@linux-foundation.org: unbreak arm]
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The double indirection here is not needed anywhere and hence (at least)
confusing.
Signed-off-by: Jan Beulich <jbeulich@novell.com>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: "David S. Miller" <davem@davemloft.net>
Acked-by: Jeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Kernel Bugzilla #11063 points out that on some architectures (e.g. x86_32)
exec'ing an ELF without a PT_GNU_STACK program header should default to an
executable stack; but this got broken by the unlimited argv feature because
stack vma is now created before the right personality has been established:
so breaking old binaries using nested function trampolines.
Therefore re-evaluate VM_STACK_FLAGS in setup_arg_pages, where stack
vm_flags used to be set, before the mprotect_fixup. Checking through
our existing VM_flags, none would have changed since insert_vm_struct:
so this seems safer than finding a way through the personality labyrinth.
Reported-by: pageexec@freemail.hu
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We only need it for the /sbin/loader hack for OSF/1 executables, and we
don't want to include it otherwise.
While we're at it, remove the redundant '&& CONFIG_ARCH_SUPPORTS_AOUT'
in the ifdef around that code. It's already dependent on __alpha__, and
CONFIG_ARCH_SUPPORTS_AOUT is hard-coded to 'y' there.
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
Acked-by: Peter Korsgaard <jacmet@sunsite.dk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Based on Roland's patch. This approach was suggested by Austin Clements
from the very beginning, and then by Linus.
As Austin pointed out, the execing task can be killed by SI_TIMER signal
because exec flushes the signal handlers, but doesn't discard the pending
signals generated by posix timers. Perhaps not a bug, but people find this
surprising. See http://bugzilla.kernel.org/show_bug.cgi?id=10460
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Austin Clements <amdragon+kernelbugzilla@mit.edu>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Even though copy_compat_strings() doesn't cache the pages,
copy_strings_kernel() and stuff indirectly called by e.g.
->load_binary() is doing that, so we need to drop the
cache contents in the end.
[found by WANG Cong <wangcong@zeuux.org>]
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
When mm destruction happens, we should pass mm_update_next_owner() the old mm.
But unfortunately new mm is passed in exec_mmap().
Thus, kernel panic is possible when a multi-threaded process uses exec().
Also, the owner member comment description is wrong. mm->owner does not
necessarily point to the thread group leader.
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: "Paul Menage" <menage@google.com>
Cc: "KAMEZAWA Hiroyuki" <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add a couple of small comments, it is not easy to see what this code does.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Now that we rely on SIGNAL_UNKILLABLE flag, de_thread() doesn't need the nasty
hack to kill the old ->child_reaper during the mt-exec.
This also means we can avoid taking tasklist_lock around zap_other_threads().
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The kernel implements readlink of /proc/pid/exe by getting the file from
the first executable VMA. Then the path to the file is reconstructed and
reported as the result.
Because of the VMA walk the code is slightly different on nommu systems.
This patch avoids separate /proc/pid/exe code on nommu systems. Instead of
walking the VMAs to find the first executable file-backed VMA we store a
reference to the exec'd file in the mm_struct.
That reference would prevent the filesystem holding the executable file
from being unmounted even after unmapping the VMAs. So we track the number
of VM_EXECUTABLE VMAs and drop the new reference when the last one is
unmapped. This avoids pinning the mounted filesystem.
[akpm@linux-foundation.org: improve comments]
[yamamoto@valinux.co.jp: fix dup_mmap]
Signed-off-by: Matt Helsley <matthltc@us.ibm.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: David Howells <dhowells@redhat.com>
Cc:"Eric W. Biederman" <ebiederm@xmission.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Hugh Dickins <hugh@veritas.com>
Signed-off-by: YAMAMOTO Takashi <yamamoto@valinux.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Remove the mem_cgroup member from mm_struct and instead adds an owner.
This approach was suggested by Paul Menage. The advantage of this approach
is that, once the mm->owner is known, using the subsystem id, the cgroup
can be determined. It also allows several control groups that are
virtually grouped by mm_struct, to exist independent of the memory
controller i.e., without adding mem_cgroup's for each controller, to
mm_struct.
A new config option CONFIG_MM_OWNER is added and the memory resource
controller selects this config option.
This patch also adds cgroup callbacks to notify subsystems when mm->owner
changes. The mm_cgroup_changed callback is called with the task_lock() of
the new task held and is called just prior to changing the mm->owner.
I am indebted to Paul Menage for the several reviews of this patchset and
helping me make it lighter and simpler.
This patch was tested on a powerpc box, it was compiled with both the
MM_OWNER config turned on and off.
After the thread group leader exits, it's moved to init_css_state by
cgroup_exit(), thus all future charges from runnings threads would be
redirected to the init_css_set's subsystem.
Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Pavel Emelianov <xemul@openvz.org>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Sudhir Kumar <skumar@linux.vnet.ibm.com>
Cc: YAMAMOTO Takashi <yamamoto@valinux.co.jp>
Cc: Hirokazu Takahashi <taka@valinux.co.jp>
Cc: David Rientjes <rientjes@google.com>,
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
Reviewed-by: Paul Menage <menage@google.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
I noticed that 2.6.24.2 calculates bprm->argv_len at do_execve(). But it
doesn't update bprm->argv_len after "remove_arg_zero() +
copy_strings_kernel()" at load_script() etc.
audit_bprm() is called from search_binary_handler() and
search_binary_handler() is called from load_script() etc. Thus, I think the
condition check
if (bprm->argv_len > (audit_argv_kb << 10))
return -E2BIG;
in audit_bprm() might return wrong result when strlen(removed_arg) !=
strlen(spliced_args). Why not update bprm->argv_len at load_script() etc. ?
By the way, 2.6.25-rc3 seems to not doing the condition check. Is the field
bprm->argv_len no longer needed?
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Ollie Wild <aaw@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* let unshare_files() give caller the displaced files_struct
* don't bother with grabbing reference only to drop it in the
caller if it hadn't been shared in the first place
* in that form unshare_files() is trivially implemented via
unshare_fd(), so we eliminate the duplicate logics in fork.c
* reset_files_struct() is not just only called for current;
it will break the system if somebody ever calls it for anything
else (we can't modify ->files of somebody else). Lose the
task_struct * argument.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* unshare_files() can fail; doing it after irreversible actions is wrong
and de_thread() is certainly irreversible.
* since we do it unconditionally anyway, we might as well do it in do_execve()
and save ourselves the PITA in binfmt handlers, etc.
* while we are at it, binfmt_som actually leaked files_struct on failure.
As a side benefit, unshare_files(), put_files_struct() and reset_files_struct()
become unexported.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
The new code that removed the limitation on the execve string size
(which was historically 32 pages) replaced it with a much softer limit
based on RLIMIT_STACK which is usually much larger than the traditional
limit. See commit b6a2fea393 ("mm:
variable length argument support") for details.
However, if you have a small stack limit (perhaps because you need lots
of stacks in a threaded environment), the new heuristic of allowing up
to 1/4th of RLIMIT_STACK to be used for argument and environment strings
could actually be smaller than the old limit.
So just say that it's ok to have up to ARG_MAX strings regardless of the
value of RLIMIT_STACK, and check the rlimit only when going over that
traditional limit.
(Of course, if you actually have a *really* small stack limit, the whole
stack itself will be limited before you hit ARG_MAX, but that has always
been true and is clearly the right behaviour anyway).
Acked-by: Carlos O'Donell <carlos@codesourcery.com>
Cc: Michael Kerrisk <michael.kerrisk@googlemail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Ollie Wild <aaw@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Add path_put() functions for releasing a reference to the dentry and
vfsmount of a struct path in the right order
* Switch from path_release(nd) to path_put(&nd->path)
* Rename dput_path() to path_put_conditional()
[akpm@linux-foundation.org: fix cifs]
Signed-off-by: Jan Blunck <jblunck@suse.de>
Signed-off-by: Andreas Gruenbacher <agruen@suse.de>
Acked-by: Christoph Hellwig <hch@lst.de>
Cc: <linux-fsdevel@vger.kernel.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Steven French <sfrench@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is the central patch of a cleanup series. In most cases there is no good
reason why someone would want to use a dentry for itself. This series reflects
that fact and embeds a struct path into nameidata.
Together with the other patches of this series
- it enforced the correct order of getting/releasing the reference count on
<dentry,vfsmount> pairs
- it prepares the VFS for stacking support since it is essential to have a
struct path in every place where the stack can be traversed
- it reduces the overall code size:
without patch series:
text data bss dec hex filename
5321639 858418 715768 6895825 6938d1 vmlinux
with patch series:
text data bss dec hex filename
5320026 858418 715768 6894212 693284 vmlinux
This patch:
Switch from nd->{dentry,mnt} to nd->path.{dentry,mnt} everywhere.
[akpm@linux-foundation.org: coding-style fixes]
[akpm@linux-foundation.org: fix cifs]
[akpm@linux-foundation.org: fix smack]
Signed-off-by: Jan Blunck <jblunck@suse.de>
Signed-off-by: Andreas Gruenbacher <agruen@suse.de>
Acked-by: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This allows us to use executables >2GB.
Based on a patch by Dave Anderson
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Dave Anderson <anderson@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Suppress A.OUT library support if CONFIG_ARCH_SUPPORTS_AOUT is not set.
Not all architectures support the A.OUT binfmt, so the ELF binfmt should not
be permitted to go looking for A.OUT libraries to load in such a case. Not
only that, but under such conditions A.OUT core dumps are not produced either.
To make this work, this patch also does the following:
(1) Makes the existence of the contents of linux/a.out.h contingent on
CONFIG_ARCH_SUPPORTS_AOUT.
(2) Renames dump_thread() to aout_dump_thread() as it's only called by A.OUT
core dumping code.
(3) Moves aout_dump_thread() into asm/a.out-core.h and makes it inline. This
is then included only where needed. This means that this bit of arch
code will be stored in the appropriate A.OUT binfmt module rather than
the core kernel.
(4) Drops A.OUT support for Blackfin (according to Mike Frysinger it's not
needed) and FRV.
This patch depends on the previous patch to move STACK_TOP[_MAX] out of
asm/a.out.h and into asm/processor.h as they're required whether or not A.OUT
format is available.
[jdike@addtoit.com: uml: re-remove accidentally restored code]
Signed-off-by: David Howells <dhowells@redhat.com>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
signal_struct->tsk points to the ->group_leader and thus we have the nasty
code in de_thread() which has to change it and restart ->real_timer if the
leader is changed.
Use "struct pid *leader_pid" instead. This also allows us to kill now
unneeded send_group_sig_info().
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Davide Libenzi <davidel@xmailserver.org>
Cc: Pavel Emelyanov <xemul@openvz.org>
Acked-by: Roland McGrath <roland@redhat.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
As Roland pointed out, we have the very old problem with exec. de_thread()
sets SIGNAL_GROUP_EXIT, kills other threads, changes ->group_leader and then
clears signal->flags. All signals (even fatal ones) sent in this window
(which is not too small) will be lost.
With this patch exec doesn't abuse SIGNAL_GROUP_EXIT. signal_group_exit(),
the new helper, should be used to detect exit_group() or exec() in progress.
It can have more users, but this patch does only strictly necessary changes.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Davide Libenzi <davidel@xmailserver.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Robin Holt <holt@sgi.com>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
It was dumb to make get_task_comm() return void. Change it to return a
pointer to the resulting output for caller convenience.
Cc: Ulrich Drepper <drepper@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
fix: http://bugzilla.kernel.org/show_bug.cgi?id=3043
only allow coredumping to the same uid that the coredumping
task runs under.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Alan Cox <alan@redhat.com>
Acked-by: Christoph Hellwig <hch@lst.de>
Acked-by: Al Viro <viro@ftp.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The coredump code always calls set_dumpable(0) when it starts (even
if RLIMIT_CORE prevents any core from being dumped). The effect of
this (via task_dumpable) is to make /proc/pid/* files owned by root
instead of the user, so the user can no longer examine his own
process--in a case where there was never any privileged data to
protect. This affects e.g. auxv, environ, fd; in Fedora (execshield)
kernels, also maps. In practice, you can only notice this when a
debugger has requested PTRACE_EVENT_EXIT tracing.
set_dumpable was only used in do_coredump for synchronization and not
intended for any security purpose. (It doesn't secure anything that wasn't
already unsecured when a process dies by SIGTERM instead of SIGQUIT.)
This changes do_coredump to check the core_waiters count as the means of
synchronization, which is sufficient. Now we leave the "dumpable" bits alone.
Signed-off-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
With pid namespaces this field is now dangerous to use explicitly, so hide
it behind the helpers.
Also the pid and pgrp fields o task_struct and signal_struct are to be
deprecated. Unfortunately this patch cannot be sent right now as this
leads to tons of warnings, so start isolating them, and deprecate later.
Actually the p->tgid == pid has to be changed to has_group_leader_pid(),
but Oleg pointed out that in case of posix cpu timers this is the same, and
thread_group_leader() is more preferable.
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Acked-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is the largest patch in the set. Make all (I hope) the places where
the pid is shown to or get from user operate on the virtual pids.
The idea is:
- all in-kernel data structures must store either struct pid itself
or the pid's global nr, obtained with pid_nr() call;
- when seeking the task from kernel code with the stored id one
should use find_task_by_pid() call that works with global pids;
- when showing pid's numerical value to the user the virtual one
should be used, but however when one shows task's pid outside this
task's namespace the global one is to be used;
- when getting the pid from userspace one need to consider this as
the virtual one and use appropriate task/pid-searching functions.
[akpm@linux-foundation.org: build fix]
[akpm@linux-foundation.org: nuther build fix]
[akpm@linux-foundation.org: yet nuther build fix]
[akpm@linux-foundation.org: remove unneeded casts]
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: Alexey Dobriyan <adobriyan@openvz.org>
Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Paul Menage <menage@google.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Use task_pid() to get leader's 'struct pid' and avoid the find_pid().
Signed-off-by: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Acked-by: Pavel Emelianov <xemul@openvz.org>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Cedric Le Goater <clg@fr.ibm.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Cc: Serge Hallyn <serue@us.ibm.com>
Cc: Herbert Poetzel <herbert@13thfloor.at>
Cc: Kirill Korotaev <dev@sw.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Rename the child_reaper() function to task_child_reaper() to be similar to
other task_* functions and to distinguish the function from 'struct
pid_namspace.child_reaper'.
Signed-off-by: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Cc: Pavel Emelianov <xemul@openvz.org>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Cedric Le Goater <clg@fr.ibm.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Cc: Serge Hallyn <serue@us.ibm.com>
Cc: Herbert Poetzel <herbert@13thfloor.at>
Cc: Kirill Korotaev <dev@sw.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
With multiple pid namespaces, a process is known by some pid_t in every
ancestor pid namespace. Every time the process forks, the child process also
gets a pid_t in every ancestor pid namespace.
While a process is visible in >=1 pid namespaces, it can see pid_t's in only
one pid namespace. We call this pid namespace it's "active pid namespace",
and it is always the youngest pid namespace in which the process is known.
This patch defines and uses a wrapper to find the active pid namespace of a
process. The implementation of the wrapper will be changed in when support
for multiple pid namespaces are added.
Changelog:
2.6.22-rc4-mm2-pidns1:
- [Pavel Emelianov, Alexey Dobriyan] Back out the change to use
task_active_pid_ns() in child_reaper() since task->nsproxy
can be NULL during task exit (so child_reaper() continues to
use init_pid_ns).
to implement child_reaper() since init_pid_ns.child_reaper to
implement child_reaper() since tsk->nsproxy can be NULL during exit.
2.6.21-rc6-mm1:
- Rename task_pid_ns() to task_active_pid_ns() to reflect that a
process can have multiple pid namespaces.
Signed-off-by: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Acked-by: Pavel Emelianov <xemul@openvz.org>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Cedric Le Goater <clg@fr.ibm.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Cc: Serge Hallyn <serue@us.ibm.com>
Cc: Herbert Poetzel <herbert@13thfloor.at>
Cc: Kirill Korotaev <dev@sw.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch uses vm_get_page_prot() to setup vma->vm_page_prot.
Though inside vm_get_page_prot() the protection flags is AND with
(VM_READ|VM_WRITE|VM_EXEC|VM_SHARED), it does not hurt correct code.
Signed-off-by: Coly Li <coyli@suse.de>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Tony Luck <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch contains the following cleanups that are now possible:
- remove the unused security_operations->inode_xattr_getsuffix
- remove the no longer used security_operations->unregister_security
- remove some no longer required exit code
- remove a bunch of no longer used exports
Signed-off-by: Adrian Bunk <bunk@kernel.org>
Acked-by: James Morris <jmorris@namei.org>
Cc: Chris Wright <chrisw@sous-sol.org>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
de_thread() yields waiting for ->group_leader to be a zombie. This deadlocks
if an rt-prio execer shares the same cpu with ->group_leader. Change the code
to use ->group_exit_task/notify_count mechanics.
This patch certainly uglifies the code, perhaps someone can suggest something
better.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Now that we don't pre-allocate the new ->sighand, we can kill the first fast
path, it doesn't make sense any longer. At best, it can save one "list_empty()"
check but leads to the code duplication.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
de_thread() pre-allocates newsighand to make sure that exec() can't fail after
killing all sub-threads. Imho, this buys nothing, but complicates the code:
- this is (mostly) needed to handle CLONE_SIGHAND without CLONE_THREAD
tasks, this is very unlikely (if ever used) case
- unless we already have some serious problems, GFP_KERNEL allocation
should not fail
- ENOMEM still can happen after de_thread(), ->sighand is not the last
object we have to allocate
Change the code to allocate the new ->sighand on demand.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There is no any reason to do recalc_sigpending() after changing ->sighand.
To begin with, recalc_sigpending() does not take ->sighand into account.
This means we don't need to take newsighand->siglock while changing sighands.
rcu_assign_pointer() provides a necessary barrier, and if another process
reads the new ->sighand it should either take tasklist_lock or it should use
lock_task_sighand() which has a corresponding smp_read_barrier_depends().
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
vfs_permission(MAY_EXEC) checks if the filesystem is mounted with "noexec", so
there's no need to repeat this check in sys_uselib() and open_exec().
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix do_coredump to detect a crash in the user mode helper process and abort
the attempt to recursively dump core to another copy of the helper process,
potentially ad-infinitum.
[akpm@linux-foundation.org: cleanups]
Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
Cc: <martin.pitt@ubuntu.com>
Cc: <wwoods@redhat.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
A rewrite of my previous post for this enhancement. It uses jeremy's
split_argv/free_argv library functions to translate core_pattern into an argv
array to be passed to the user mode helper process. It also adds a
translation to format_corename such that the origional value of RLIMIT_CORE
can be passed to userspace as an argument.
Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
Cc: <martin.pitt@ubuntu.com>
Cc: <wwoods@redhat.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
For some time /proc/sys/kernel/core_pattern has been able to set its output
destination as a pipe, allowing a user space helper to receive and
intellegently process a core. This infrastructure however has some
shortcommings which can be enhanced. Specifically:
1) The coredump code in the kernel should ignore RLIMIT_CORE limitation
when core_pattern is a pipe, since file system resources are not being
consumed in this case, unless the user application wishes to save the core,
at which point the app is restricted by usual file system limits and
restrictions.
2) The core_pattern code should be able to parse and pass options to the
user space helper as an argv array. The real core limit of the uid of the
crashing proces should also be passable to the user space helper (since it
is overridden to zero when called).
3) Some miscellaneous bugs need to be cleaned up (specifically the
recognition of a recursive core dump, should the user mode helper itself
crash. Also, the core dump code in the kernel should not wait for the user
mode helper to exit, since the same context is responsible for writing to
the pipe, and a read of the pipe by the user mode helper will result in a
deadlock.
This patch:
Remove the check of RLIMIT_CORE if core_pattern is a pipe. In the event that
core_pattern is a pipe, the entire core will be fed to the user mode helper.
Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
Cc: <martin.pitt@ubuntu.com>
Cc: <wwoods@redhat.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
list_del() hardly can fail, so checking for return value is pointless
(and current code always return 0).
Nobody really cared that return value anyway.
Signed-off-by: Alexey Dobriyan <adobriyan@sw.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Switch single-linked binfmt formats list to usual list_head's. This leads
to one-liners in register_binfmt() and unregister_binfmt(). The downside
is one pointer more in struct linux_binfmt. This is not a problem, since
the set of registered binfmts on typical box is very small -- (ELF +
something distro enabled for you).
Test-booted, played with executable .txt files, modprobe/rmmod binfmt_misc.
Signed-off-by: Alexey Dobriyan <adobriyan@sw.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This simplifies signalfd code, by avoiding it to remain attached to the
sighand during its lifetime.
In this way, the signalfd remain attached to the sighand only during
poll(2) (and select and epoll) and read(2). This also allows to remove
all the custom "tsk == current" checks in kernel/signal.c, since
dequeue_signal() will only be called by "current".
I think this is also what Ben was suggesting time ago.
The external effect of this, is that a thread can extract only its own
private signals and the group ones. I think this is an acceptable
behaviour, in that those are the signals the thread would be able to
fetch w/out signalfd.
Signed-off-by: Davide Libenzi <davidel@xmailserver.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
de_thread:
if (atomic_read(&oldsighand->count) <= 1)
BUG_ON(atomic_read(&sig->count) != 1);
This is not safe without the rmb() in between. The results of two
correctly ordered __exit_signal()->atomic_dec_and_test()'s could be seen
out of order on our CPU.
The same is true for the "thread_group_empty()" case, __unhash_process()'s
changes could be seen before atomic_dec_and_test(&sig->count).
On some platforms (including i386) atomic_read() doesn't provide even the
compiler barrier, in that case these checks are simply racy.
Remove these BUG_ON()'s. Alternatively, we can do something like
BUG_ON( ({ smp_rmb(); atomic_read(&sig->count) != 1; }) );
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
With this patch any thread can dequeue its own private signals via signalfd,
even if it was created by another sub-thread.
To do so, we pass "current" to dequeue_signal() if the caller is from the same
thread group. This also fixes the scheduling of posix timers broken by the
previous patch.
If the caller doesn't belong to this thread group, we can't handle __SI_TIMER
case properly anyway. Perhaps we should forbid the cross-process signalfd usage
and convert ctx->tsk to ctx->sighand.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Davide Libenzi <davidel@xmailserver.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Michael Kerrisk <mtk-manpages@gmx.net>
Cc: Roland McGrath <roland@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This fixes a vulnerability in the "parent process death signal"
implementation discoverd by Wojciech Purczynski of COSEINC PTE Ltd.
and iSEC Security Research.
http://marc.info/?l=bugtraq&m=118711306802632&w=2
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch changes mm_struct.dumpable to a pair of bit flags.
set_dumpable() converts three-value dumpable to two flags and stores it into
lower two bits of mm_struct.flags instead of mm_struct.dumpable.
get_dumpable() behaves in the opposite way.
[akpm@linux-foundation.org: export set_dumpable]
Signed-off-by: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: David Howells <dhowells@redhat.com>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Remove the arg+env limit of MAX_ARG_PAGES by copying the strings directly from
the old mm into the new mm.
We create the new mm before the binfmt code runs, and place the new stack at
the very top of the address space. Once the binfmt code runs and figures out
where the stack should be, we move it downwards.
It is a bit peculiar in that we have one task with two mm's, one of which is
inactive.
[a.p.zijlstra@chello.nl: limit stack size]
Signed-off-by: Ollie Wild <aaw@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: <linux-arch@vger.kernel.org>
Cc: Hugh Dickins <hugh@veritas.com>
[bunk@stusta.de: unexport bprm_mm_init]
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The purpose of audit_bprm() is to log the argv array to a userspace daemon at
the end of the execve system call. Since user-space hasn't had time to run,
this array is still in pristine state on the process' stack; so no need to
copy it, we can just grab it from there.
In order to minimize the damage to audit_log_*() copy each string into a
temporary kernel buffer first.
Currently the audit code requires that the full argument vector fits in a
single packet. So currently it does clip the argv size to a (sysctl) limit,
but only when execve auditing is enabled.
If the audit protocol gets extended to allow for multiple packets this check
can be removed.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ollie Wild <aaw@google.com>
Cc: <linux-audit@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We don't allow loading ELF shared library from noexec points so the
same should apply to sys_uselib aswell.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: Ulrich Drepper <drepper@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Make sysctl/kernel/core_pattern and fs/exec.c agree on maximum core
filename size and change it to 128, so that extensive patterns such as
'/local/cores/%e-%h-%s-%t-%p.core' won't result in truncated filename
generation.
Signed-off-by: Dan Aloni <da-x@monatomic.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'audit.b38' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/audit-current:
[PATCH] Abnormal End of Processes
[PATCH] match audit name data
[PATCH] complete message queue auditing
[PATCH] audit inode for all xattr syscalls
[PATCH] initialize name osid
[PATCH] audit signal recipients
[PATCH] add SIGNAL syscall class (v3)
[PATCH] auditing ptrace
This patch series implements the new signalfd() system call.
I took part of the original Linus code (and you know how badly it can be
broken :), and I added even more breakage ;) Signals are fetched from the same
signal queue used by the process, so signalfd will compete with standard
kernel delivery in dequeue_signal(). If you want to reliably fetch signals on
the signalfd file, you need to block them with sigprocmask(SIG_BLOCK). This
seems to be working fine on my Dual Opteron machine. I made a quick test
program for it:
http://www.xmailserver.org/signafd-test.c
The signalfd() system call implements signal delivery into a file descriptor
receiver. The signalfd file descriptor if created with the following API:
int signalfd(int ufd, const sigset_t *mask, size_t masksize);
The "ufd" parameter allows to change an existing signalfd sigmask, w/out going
to close/create cycle (Linus idea). Use "ufd" == -1 if you want a brand new
signalfd file.
The "mask" allows to specify the signal mask of signals that we are interested
in. The "masksize" parameter is the size of "mask".
The signalfd fd supports the poll(2) and read(2) system calls. The poll(2)
will return POLLIN when signals are available to be dequeued. As a direct
consequence of supporting the Linux poll subsystem, the signalfd fd can use
used together with epoll(2) too.
The read(2) system call will return a "struct signalfd_siginfo" structure in
the userspace supplied buffer. The return value is the number of bytes copied
in the supplied buffer, or -1 in case of error. The read(2) call can also
return 0, in case the sighand structure to which the signalfd was attached,
has been orphaned. The O_NONBLOCK flag is also supported, and read(2) will
return -EAGAIN in case no signal is available.
If the size of the buffer passed to read(2) is lower than sizeof(struct
signalfd_siginfo), -EINVAL is returned. A read from the signalfd can also
return -ERESTARTSYS in case a signal hits the process. The format of the
struct signalfd_siginfo is, and the valid fields depends of the (->code &
__SI_MASK) value, in the same way a struct siginfo would:
struct signalfd_siginfo {
__u32 signo; /* si_signo */
__s32 err; /* si_errno */
__s32 code; /* si_code */
__u32 pid; /* si_pid */
__u32 uid; /* si_uid */
__s32 fd; /* si_fd */
__u32 tid; /* si_fd */
__u32 band; /* si_band */
__u32 overrun; /* si_overrun */
__u32 trapno; /* si_trapno */
__s32 status; /* si_status */
__s32 svint; /* si_int */
__u64 svptr; /* si_ptr */
__u64 utime; /* si_utime */
__u64 stime; /* si_stime */
__u64 addr; /* si_addr */
};
[akpm@linux-foundation.org: fix signalfd_copyinfo() on i386]
Signed-off-by: Davide Libenzi <davidel@xmailserver.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
attach_pid() currently takes a pid_t and then uses find_pid() to find the
corresponding struct pid. Sometimes we already have the struct pid. We can
then skip find_pid() if attach_pid() were to take a struct pid parameter.
Signed-off-by: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Cc: Cedric Le Goater <clg@fr.ibm.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Cc: Serge Hallyn <serue@us.ibm.com>
Cc: <containers@lists.osdl.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Hi,
I have been working on some code that detects abnormal events based on audit
system events. One kind of event that we currently have no visibility for is
when a program terminates due to segfault - which should never happen on a
production machine. And if it did, you'd want to investigate it. Attached is a
patch that collects these events and sends them into the audit system.
Signed-off-by: Steve Grubb <sgrubb@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
When a binary format is unregistered and re-registered, register_binfmt
fails with -EBUSY. The reason is that unregister_binfmt does not set
fmt->next to NULL, and seeing (fmt->next != NULL), register_binfmt fails
with -EBUSY.
One can find his way around by explicitly setting fmt->next to NULL after
unregistering, but that is kind of unclean (one should better be using only
the interfaces, and not the interal members, isn't it?)
Attached one-liner can fix it.
Signed-off-by: Kalash Nainwal <kalash.nainwal@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Petr Tesarik discovered a problem in remove_arg_zero(). He writes:
When a script is loaded, load_script() replaces argv[0] with the
name of the interpreter and the filename passed to the exec syscall.
However, there is no guarantee that the length of the interpreter
name plus the length of the filename is greater than the length of
the original argv[0]. If the difference happens to cross a page boundary,
setup_arg_pages() will call put_dirty_page() [aka install_arg_page()]
with an address outside the VMA.
Therefore, remove_arg_zero() must free all pages which would be unused
after the argument is removed.
So, rewrite the remove_arg_zero function without gotos, with a few comments,
and with the commonly used explicit index/offset. This fixes the problem
and makes it easier to understand as well.
[a.p.zijlstra@chello.nl: add comment]
Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Petr Tesarik <ptesarik@suse.cz>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The patch checks for "|" in the pattern not the output and doesn't nail a
pid on to a piped name (as it is a program name not a file)
Also fixes a very very obscure security corner case. If you happen to have
decided on a core pattern that starts with the program name then the user
can run a program called "|myevilhack" as it stands. I doubt anyone does
this.
Signed-off-by: Alan Cox <alan@redhat.com>
Confirmed-by: Christopher S. Aker <caker@theshore.net>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Replace appropriate pairs of "kmem_cache_alloc()" + "memset(0)" with the
corresponding "kmem_cache_zalloc()" call.
Signed-off-by: Robert P. J. Day <rpjday@mindspring.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Andi Kleen <ak@muc.de>
Cc: Roland McGrath <roland@redhat.com>
Cc: James Bottomley <James.Bottomley@steeleye.com>
Cc: Greg KH <greg@kroah.com>
Acked-by: Joel Becker <Joel.Becker@oracle.com>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Jan Kara <jack@ucw.cz>
Cc: Michael Halcrow <mhalcrow@us.ibm.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: James Morris <jmorris@namei.org>
Cc: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently, each fdtable supports three dynamically-sized arrays of data: the
fdarray and two fdsets. The code allows the number of fds supported by the
fdarray (fdtable->max_fds) to differ from the number of fds supported by each
of the fdsets (fdtable->max_fdset).
In practice, it is wasteful for these two sizes to differ: whenever we hit a
limit on the smaller-capacity structure, we will reallocate the entire fdtable
and all the dynamic arrays within it, so any delta in the memory used by the
larger-capacity structure will never be touched at all.
Rather than hogging this excess, we shouldn't even allocate it in the first
place, and keep the capacities of the fdarray and the fdsets equal. This
patch removes fdtable->max_fdset. As an added bonus, most of the supporting
code becomes simpler.
Signed-off-by: Vadim Lobanov <vlobanov@speakeasy.net>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Dipankar Sarma <dipankar@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Add a per pid_namespace child-reaper. This is needed so processes are reaped
within the same pid space and do not spill over to the parent pid space. Its
also needed so containers preserve existing semantic that pid == 1 would reap
orphaned children.
This is based on Eric Biederman's patch: http://lkml.org/lkml/2006/2/6/285
Signed-off-by: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Signed-off-by: Cedric Le Goater <clg@fr.ibm.com>
Cc: Kirill Korotaev <dev@openvz.org>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Herbert Poetzl <herbert@13thfloor.at>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This patch changes struct file to use struct path instead of having
independent pointers to struct dentry and struct vfsmount, and converts all
users of f_{dentry,vfsmnt} in fs/ to use f_path.{dentry,mnt}.
Additionally, it adds two #define's to make the transition easier for users of
the f_dentry and f_vfsmnt.
Signed-off-by: Josef "Jeff" Sipek <jsipek@cs.sunysb.edu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
On Sat, Dec 02, 2006 at 11:47:44PM +0300, Alexey Dobriyan wrote:
> David Binderman compiled 2.6.19 with icc and grepped for "was set but never
> used". Many warnings are on
> http://coderock.org/kj/unused-2.6.19-fs
Heh, the very first line:
fs/exec.c(1465): remark #593: variable "flag" was set but never used
fs/exec.c:
1477 /*
1478 * We cannot trust fsuid as being the "true" uid of the
1479 * process nor do we know its entire history. We only know it
1480 * was tainted so we dump it as root in mode 2.
1481 */
1482 if (mm->dumpable == 2) { /* Setuid core dump mode */
1483 flag = O_EXCL; /* Stop rewrite attacks */
1484 current->fsuid = 0; /* Dump root private */
1485 }
And then filp_open follows with "flag" totally ignored.
(akpm: this restores the code to Alan's original version. Andi's "Support
piping into commands in /proc/sys/kernel/core_pattern" (cset d025c9db) broke
it).
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: <stable@kerenl.org>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
SLAB_KERNEL is an alias of GFP_KERNEL.
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Replace references to system_utsname to the per-process uts namespace
where appropriate. This includes things like uname.
Changes: Per Eric Biederman's comments, use the per-process uts namespace
for ELF_PLATFORM, sunrpc, and parts of net/ipv4/ipconfig.c
[jdike@addtoit.com: UML fix]
[clg@fr.ibm.com: cleanup]
[akpm@osdl.org: build fix]
Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
Cc: Kirill Korotaev <dev@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Herbert Poetzl <herbert@13thfloor.at>
Cc: Andrey Savochkin <saw@sw.ru>
Signed-off-by: Cedric Le Goater <clg@fr.ibm.com>
Cc: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Using the infrastructure created in previous patches implement support to
pipe core dumps into programs.
This is done by overloading the existing core_pattern sysctl
with a new syntax:
|program
When the first character of the pattern is a '|' the kernel will instead
threat the rest of the pattern as a command to run. The core dump will be
written to the standard input of that program instead of to a file.
This is useful for having automatic core dump analysis without filling up
disks. The program can do some simple analysis and save only a summary of
the core dump.
The core dump proces will run with the privileges and in the name space of
the process that caused the core dump.
I also increased the core pattern size to 128 bytes so that longer command
lines fit.
Most of the changes comes from allowing core dumps without seeks. They are
fairly straight forward though.
One small incompatibility is that if someone had a core pattern previously
that started with '|' they will get suddenly new behaviour. I think that's
unlikely to be a real problem though.
Additional background:
> Very nice, do you happen to have a program that can accept this kind of
> input for crash dumps? I'm guessing that the embedded people will
> really want this functionality.
I had a cheesy demo/prototype. Basically it wrote the dump to a file again,
ran gdb on it to get a backtrace and wrote the summary to a shared directory.
Then there was a simple CGI script to generate a "top 10" crashes HTML
listing.
Unfortunately this still had the disadvantage to needing full disk space for a
dump except for deleting it afterwards (in fact it was worse because over the
pipe holes didn't work so if you have a holey address map it would require
more space).
Fortunately gdb seems to be happy to handle /proc/pid/fd/xxx input pipes as
cores (at least it worked with zsh's =(cat core) syntax), so it would be
likely possible to do it without temporary space with a simple wrapper that
calls it in the right way. I ran out of time before doing that though.
The demo prototype scripts weren't very good. If there is really interest I
can dig them out (they are currently on a laptop disk on the desk with the
laptop itself being in service), but I would recommend to rewrite them for any
serious application of this and fix the disk space problem.
Also to be really useful it should probably find a way to automatically fetch
the debuginfos (I cheated and just installed them in advance). If nobody else
does it I can probably do the rewrite myself again at some point.
My hope at some point was that desktops would support it in their builtin
crash reporters, but at least the KDE people I talked too seemed to be happy
with their user space only solution.
Alan sayeth:
I don't believe that piping as such as neccessarily the right model, but
the ability to intercept and processes core dumps from user space is asked
for by many enterprise users as well. They want to know about, capture,
analyse and process core dumps, often centrally and in automated form.
[akpm@osdl.org: loff_t != unsigned long]
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
There were a few accounting data/macros that are used in CSA but are #ifdef'ed
inside CONFIG_BSD_PROCESS_ACCT. This patch is to change those ifdef's from
CONFIG_BSD_PROCESS_ACCT to CONFIG_TASK_XACCT. A few defines are moved from
kernel/acct.c and include/linux/acct.h to kernel/tsacct.c and
include/linux/tsacct_kern.h.
Signed-off-by: Jay Lan <jlan@sgi.com>
Cc: Shailabh Nagar <nagar@watson.ibm.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Jes Sorensen <jes@sgi.com>
Cc: Chris Sturtivant <csturtiv@sgi.com>
Cc: Tony Ernst <tee@sgi.com>
Cc: Guillaume Thouvenin <guillaume.thouvenin@bull.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Fixed race on put_files_struct on exec with proc. Restoring files on
current on error path may lead to proc having a pointer to already kfree-d
files_struct.
->files changing at exit.c and khtread.c are safe as exit_files() makes all
things under lock.
Found during OpenVZ stress testing.
[akpm@osdl.org: add export]
Signed-off-by: Pavel Emelianov <xemul@openvz.org>
Signed-off-by: Kirill Korotaev <dev@openvz.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Ingo Oeser pointed out that because current expands to an inline function
it is more space efficient and somewhat faster to simply keep a cached copy
of current in another variable. This patch implements that for the
de_thread function.
(akpm: saves nearly 100 bytes of text on x86)
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
In de_thread we move pids from one process to another, a rather ugly case.
The function transfer_pid makes it clear what we are doing, and makes the
action atomic. This is useful we ever want to atomically traverse the
process group and session lists, in a rcu safe manner.
Even if the atomic properties this change should be a win as transfer_pid
should be less code to execute than executing both attach_pid and
detach_pid, and this should make de_thread slightly smaller as only a
single function call needs to be emitted. The only downside is that the
code might be slower to execute as the odds are against transfer_pid being
in cache.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This fixes the locking error noticed by lockdep:
=============================================
[ INFO: possible recursive locking detected ]
---------------------------------------------
init/1 is trying to acquire lock:
(&sighand->siglock){....}, at: [<c047a78a>] flush_old_exec+0x3ae/0x859
but task is already holding lock:
(&sighand->siglock){....}, at: [<c047a77a>] flush_old_exec+0x39e/0x859
other info that might help us debug this:
2 locks held by init/1:
#0: (tasklist_lock){..--}, at: [<c047a76a>] flush_old_exec+0x38e/0x859
#1: (&sighand->siglock){....}, at: [<c047a77a>] flush_old_exec+0x39e/0x859
stack backtrace:
[<c04051e1>] show_trace_log_lvl+0x54/0xfd
[<c040579d>] show_trace+0xd/0x10
[<c04058b6>] dump_stack+0x19/0x1b
[<c043b33a>] __lock_acquire+0x773/0x997
[<c043bacf>] lock_acquire+0x4b/0x6c
[<c060630b>] _spin_lock+0x19/0x28
[<c047a78a>] flush_old_exec+0x3ae/0x859
[<c0498053>] load_elf_binary+0x4aa/0x1628
[<c0479cab>] search_binary_handler+0xa7/0x24e
[<c047b577>] do_execve+0x15b/0x1f9
[<c04022b4>] sys_execve+0x29/0x4d
[<c0403faf>] syscall_call+0x7/0xb
Signed-off-by: Arjan van de Ven <arjan@infradead.org>
Signed-off-by: Dave Jones <davej@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The check in open_exec() for inode->i_mode & 0111 has been made
redundant by the fix to permission().
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
(cherry picked from 1d3741c5d991686699f100b65b9956f7ee7ae0ae commit)
The check in prepare_binfmt() for inode->i_mode & 0111 is redundant,
since open_exec() will already have done that.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
(cherry picked from 822dec482ced07af32c378cd936d77345786572b commit)
This patch optimizes zap_threads() for the case when there are no ->mm
users except the current's thread group. In that case we can avoid
'for_each_process()' loop.
It also adds a useful invariant: SIGNAL_GROUP_EXIT (if checked under
->siglock) always implies that all threads (except may be current) have
pending SIGKILL.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This is a preparation for the next patch. No functional changes.
Basically, this patch moves '->flags & SIGNAL_GROUP_EXIT' check into
zap_threads(), and 'complete(vfork_done)' into coredump_wait outside of
->mmap_sem protected area.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This patch removes tasklist_lock from zap_threads().
This is safe wrt:
do_exit:
The caller holds mm->mmap_sem. This means that task which
shares the same ->mm can't pass exit_mm(), so it can't be
unhashed from init_task.tasks or ->thread_group lists.
fork:
None of sub-threads can fork after zap_process(leader). All
processes which were created before this point should be
visible to zap_threads() because copy_process() adds the new
process to the tail of init_task.tasks list, and ->siglock
lock/unlock provides a memory barrier.
de_thread:
It does list_replace_rcu(&leader->tasks, ¤t->tasks).
So zap_threads() will see either old or new leader, it does
not matter. However, it can change p->sighand, so we should
use lock_task_sighand() in zap_process().
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
With this patch zap_process() sets SIGNAL_GROUP_EXIT while sending SIGKILL to
the thread group. This means that a TASK_TRACED task
1. Will be awakened by signal_wake_up(1)
2. Can't sleep again via ptrace_notify()
3. Can't go to do_signal_stop() after return
from ptrace_stop() in get_signal_to_deliver()
So we can remove all ptrace related stuff from coredump path.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
With this patch a thread group is killed atomically under ->siglock. This is
faster because we can use sigaddset() instead of force_sig_info() and this is
used in further patches.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
zap_threads() iterates over all threads to find those ones which share
current->mm. All threads in the thread group share the same ->mm, so we can
skip entire thread group if it has another ->mm.
This patch shifts the killing of thread group into the newly added
zap_process() function. This looks as unnecessary complication, but it is
used in further patches.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
We should keep the value of old_leader->tasks.next in de_thread, otherwise
we can't do for_each_process/do_each_thread without tasklist_lock held.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
To keep the dcache from filling up with dead /proc entries we flush them on
process exit. However over the years that code has gotten hairy with a
dentry_pointer and a lock in task_struct and misdocumented as a correctness
feature.
I have rewritten this code to look and see if we have a corresponding entry in
the dcache and if so flush it on process exit. This removes the extra fields
in the task_struct and allows me to trivially handle the case of a
/proc/<tgid>/task/<pid> entry as well as the current /proc/<pid> entries.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This patch removes the steal_locks() function.
steal_locks() doesn't work correctly with any filesystem that does it's own
lock management, including NFS, CIFS, etc.
In addition it has weird semantics on local filesystems in case tasks
sharing file-descriptor tables are doing POSIX locking operations in
parallel to execve().
The steal_locks() function has an effect on applications doing:
clone(CLONE_FILES)
/* in child */
lock
execve
lock
POSIX locks acquired before execve (by "child", "parent" or any further
task sharing files_struct) will after the execve be owned exclusively by
"child".
According to Chris Wright some LSB/LTP kind of suite triggers without the
stealing behavior, but there's no known real-world application that would
also fail.
Apps using NPTL are not affected, since all other threads are killed before
execve.
Apps using LinuxThreads are only affected if they
- have multiple threads during exec (LinuxThreads doesn't kill other
threads, the app may do it with pthread_kill_other_threads_np())
- rely on POSIX locks being inherited across exec
Both conditions are documented, but not their interaction.
Apps using clone() natively are affected if they
- use clone(CLONE_FILES)
- rely on POSIX locks being inherited across exec
The above scenarios are unlikely, but possible.
If the patch is vetoed, there's a plan B, that involves mostly keeping the
weird stealing semantics, but changing the way lock ownership is handled so
that network and local filesystems work consistently.
That would add more complexity though, so this solution seems to be
preferred by most people.
Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: Matthew Wilcox <willy@debian.org>
Cc: Chris Wright <chrisw@sous-sol.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Steven French <sfrench@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
While we can currently walk through thread groups, process groups, and
sessions with just the rcu_read_lock, this opens the door to walking the
entire task list.
We already have all of the other RCU guarantees so there is no cost in
doing this, this should be enough so that proc can stop taking the
tasklist lock during readdir.
prev_task was killed because it has no users, and using it will miss new
tasks when doing an rcu traversal.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This is two distinct changes.
- Not changing our real parents.
- Not changing our ptrace parents.
Not changing our real parents is trivially correct because both tasks
have the same real parents as they are part of a thread group. Now that
we demote the leader to a thread there is no longer any reason to change
it's parentage.
Not changing our ptrace parents is a user visible change if someone
looks hard enough. I don't think user space applications will care or
even notice.
In the practical and I think common case a debugger will have attached
to all of the threads using the same ptrace flags. From my quick skim
of strace and gdb that appears to be the case. Which if true means
debuggers will not notice a change.
Before this point we have already generated a ptrace event in do_exit
that reports the leaders pid has died so de_thread is visible to a
debugger. Which means attempting to hide this case by copying flags
around appears excessive.
By not doing anything it avoids all of the weird locking issues between
de_thread and ptrace attach, and removes one case from consideration for
fixing the ptrace locking.
This only addresses Oleg's first concern with ptrace_attach, that of the
problems caused by reparenting. Oleg's second concern is essentially a
race between ptrace_attach and release_task that causes an oops when we
get to force_sig_specific. There is nothing special about de_thread
with respect to that race.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The only record we have of the real-time age of a process, regardless of
execs it's done, is start_time. When a non-leader thread exec, the
original start_time of the process is lost. Things looking at the
real-time age of the process are fooled, for example the process accounting
record when the process finally dies. This change makes the oldest
start_time stick around with the process after a non-leader exec. This way
the association between PID and start_time is kept constant, which seems
correct to me.
Signed-off-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Oleg Nesterov spotted two interesting bugs with the current de_thread
code. The simplest is a long standing double decrement of
__get_cpu_var(process_counts) in __unhash_process. Caused by
two processes exiting when only one was created.
The other is that since we no longer detach from the thread_group list
it is possible for do_each_thread when run under the tasklist_lock to
see the same task_struct twice. Once on the task list as a
thread_group_leader, and once on the thread list of another
thread.
The double appearance in do_each_thread can cause a double increment
of mm_core_waiters in zap_threads resulting in problems later on in
coredump_wait.
To remedy those two problems this patch takes the simple approach
of changing the old thread group leader into a child thread.
The only routine in release_task that cares is __unhash_process,
and it can be trivially seen that we handle cleaning up a
thread group leader properly.
Since de_thread doesn't change the pid of the exiting leader process
and instead shares it with the new leader process. I change
thread_group_leader to recognize group leadership based on the
group_leader field and not based on pids. This should also be
slightly cheaper then the existing thread_group_leader macro.
I performed a quick audit and I couldn't see any user of
thread_group_leader that cared about the difference.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
