SELinux tries to support setting/clearing of /proc/pid/attr attributes
from the shell by ignoring terminating newlines and treating an
attribute value that begins with a NUL or newline as an attempt to
clear the attribute. However, the test for clearing attributes has
always been wrong; it has an off-by-one error, and this could further
lead to reading past the end of the allocated buffer since commit
bb646cdb12 ("proc_pid_attr_write():
switch to memdup_user()"). Fix the off-by-one error.
Even with this fix, setting and clearing /proc/pid/attr attributes
from the shell is not straightforward since the interface does not
support multiple write() calls (so shells that write the value and
newline separately will set and then immediately clear the attribute,
requiring use of echo -n to set the attribute), whereas trying to use
echo -n "" to clear the attribute causes the shell to skip the
write() call altogether since POSIX says that a zero-length write
causes no side effects. Thus, one must use echo -n to set and echo
without -n to clear, as in the following example:
$ echo -n unconfined_u:object_r:user_home_t:s0 > /proc/$$/attr/fscreate
$ cat /proc/$$/attr/fscreate
unconfined_u:object_r:user_home_t:s0
$ echo "" > /proc/$$/attr/fscreate
$ cat /proc/$$/attr/fscreate
Note the use of /proc/$$ rather than /proc/self, as otherwise
the cat command will read its own attribute value, not that of the shell.
There are no users of this facility to my knowledge; possibly we
should just get rid of it.
UPDATE: Upon further investigation it appears that a local process
with the process:setfscreate permission can cause a kernel panic as a
result of this bug. This patch fixes CVE-2017-2618.
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
[PM: added the update about CVE-2017-2618 to the commit description]
Cc: stable@vger.kernel.org # 3.5: d6ea83ec68
Signed-off-by: Paul Moore <paul@paul-moore.com>
Otherwise some mask and inmask tokens with MAY_APPEND flag may not work
as expected.
Signed-off-by: Lans Zhang <jia.zhang@windriver.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
On failure to return a pathname from ima_d_path(), a pointer to
dname is returned, which is subsequently used in the IMA measurement
list, the IMA audit records, and other audit logging. Saving the
pointer to dname for later use has the potential to race with rename.
Intead of returning a pointer to dname on failure, this patch returns
a pointer to a copy of the filename.
Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Cc: stable@vger.kernel.org
Add net.ipv4.ip_unprivileged_port_start, which is a per namespace sysctl
that denotes the first unprivileged inet port in the namespace. To
disable all privileged ports set this to zero. It also checks for
overlap with the local port range. The privileged and local range may
not overlap.
The use case for this change is to allow containerized processes to bind
to priviliged ports, but prevent them from ever being allowed to modify
their container's network configuration. The latter is accomplished by
ensuring that the network namespace is not a child of the user
namespace. This modification was needed to allow the container manager
to disable a namespace's priviliged port restrictions without exposing
control of the network namespace to processes in the user namespace.
Signed-off-by: Krister Johansen <kjlx@templeofstupid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
With previous changes every location that tests for
LSM_UNSAFE_PTRACE_CAP also tests for LSM_UNSAFE_PTRACE making the
LSM_UNSAFE_PTRACE_CAP redundant, so remove it.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Now that we have user namespaces and non-global capabilities verify
the tracer has capabilities in the relevant user namespace instead
of in the current_user_ns().
As the test for setting LSM_UNSAFE_PTRACE_CAP is currently
ptracer_capable(p, current_user_ns()) and the new task credentials are
in current_user_ns() this change does not have any user visible change
and simply moves the test to where it is used, making the code easier
to read.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Don't reset euid and egid when the tracee has CAP_SETUID in
it's user namespace. I punted on relaxing this permission check
long ago but now that I have read this code closely it is clear
it is safe to test against CAP_SETUID in the user namespace.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Some usermode helper applications are defined at kernel build time, while
others can be changed at runtime. To provide a sane way to filter these, add a
new kernel option "STATIC_USERMODEHELPER". This option routes all
call_usermodehelper() calls through this binary, no matter what the caller
wishes to have called.
The new binary (by default set to /sbin/usermode-helper, but can be changed
through the STATIC_USERMODEHELPER_PATH option) can properly filter the
requested programs to be run by the kernel by looking at the first argument
that is passed to it. All other options should then be passed onto the proper
program if so desired.
To disable all call_usermodehelper() calls by the kernel, set
STATIC_USERMODEHELPER_PATH to an empty string.
Thanks to Neil Brown for the idea of this feature.
Cc: NeilBrown <neilb@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
There are a number of usermode helper binaries that are "hard coded" in
the kernel today, so mark them as "const" to make it harder for someone
to change where the variables point to.
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Thomas Sailer <t.sailer@alumni.ethz.ch>
Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Cc: Johan Hovold <johan@kernel.org>
Cc: Alex Elder <elder@kernel.org>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Cc: Jeff Layton <jlayton@poochiereds.net>
Cc: David Howells <dhowells@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
I am still tired of having to find indirect ways to determine
what security modules are active on a system. I have added
/sys/kernel/security/lsm, which contains a comma separated
list of the active security modules. No more groping around
in /proc/filesystems or other clever hacks.
Unchanged from previous versions except for being updated
to the latest security next branch.
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Acked-by: John Johansen <john.johansen@canonical.com>
Acked-by: Paul Moore <paul@paul-moore.com>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: James Morris <james.l.morris@oracle.com>
The kernel build bot turned up a bad config combination when
CONFIG_SECURITY_APPARMOR is y and CONFIG_SECURITY_APPARMOR_HASH is n,
resulting in the build error
security/built-in.o: In function `aa_unpack':
(.text+0x841e2): undefined reference to `aa_g_hash_policy'
Signed-off-by: John Johansen <john.johansen@canonical.com>
If this sysctl is set to non-zero and a process with CAP_MAC_ADMIN in
the root namespace has created an AppArmor policy namespace,
unprivileged processes will be able to change to a profile in the
newly created AppArmor policy namespace and, if the profile allows
CAP_MAC_ADMIN and appropriate file permissions, will be able to load
policy in the respective policy namespace.
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
Allow a profile to carry extra data that can be queried via userspace.
This provides a means to store extra data in a profile that a trusted
helper can extract and use from live policy.
Signed-off-by: William Hua <william.hua@canonical.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
apparmor should be checking the SECURITY_CAP_NOAUDIT constant. Also
in complain mode make it so apparmor can elect to log a message,
informing of the check.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Allow turning off the computation of the policy hashes via the
apparmor.hash_policy kernel parameter.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Moving the use of fqname to later allows learning profiles to be based
on the fqname request instead of just the hname. It also allows cleaning
up some of the name parsing and lookup by allowing the use of
the fqlookupn_profile() lib fn.
Signed-off-by: John Johansen <john.johansen@canonical.com>
The aad macro can replace aad strings when it is not intended to. Switch
to a fn macro so it is only applied when intended.
Also at the same time cleanup audit_data initialization by putting
common boiler plate behind a macro, and dropping the gfp_t parameter
which will become useless.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Having ops be an integer that is an index into an op name table is
awkward and brittle. Every op change requires an edit for both the
op constant and a string in the table. Instead switch to using const
strings directly, eliminating the need for the table that needs to
be kept in sync.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Trying to update the task cred while the task current cred is not the
real cred will result in an error at the cred layer. Avoid this by
failing early and delaying the update.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Verify that profiles in a load set specify the same policy ns and
audit the name of the policy ns that policy is being loaded for.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Store loaded policy and allow introspecting it through apparmorfs. This
has several uses from debugging, policy validation, and policy checkpoint
and restore for containers.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Policy management will be expanded beyond traditional unconfined root.
This will require knowning the profile of the task doing the management
and the ns view.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Prepare for a tighter pairing of user namespaces and apparmor policy
namespaces, by making the ns to be viewed available.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Prepare for a tighter pairing of user namespaces and apparmor policy
namespaces, by making the ns to be viewed available and checking
that the user namespace level is the same as the policy ns level.
This strict pairing will be relaxed once true support of user namespaces
lands.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Borrow the special null device file from selinux to "close" fds that
don't have sufficient permissions at exec time.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Commit 9f834ec18d ("binfmt_elf: switch to new creds when switching to new mm")
changed when the creds are installed by the binfmt_elf handler. This
affects which creds are used to mmap the executable into the address
space. Which can have an affect on apparmor policy.
Add a flag to apparmor at
/sys/kernel/security/apparmor/features/domain/fix_binfmt_elf_mmap
to make it possible to detect this semantic change so that the userspace
tools and the regression test suite can correctly deal with the change.
BugLink: http://bugs.launchpad.net/bugs/1630069
Signed-off-by: John Johansen <john.johansen@canonical.com>
Instead of testing whether a given dfa exists in every code path, have
a default null dfa that is used when loaded policy doesn't provide a
dfa.
This will let us get rid of special casing and avoid dereference bugs
when special casing is missed.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Newer policy will combine the file and policydb dfas, allowing for
better optimizations. However to support older policy we need to
keep the ability to address the "file" dfa separately. So dup
the policydb as if it is the file dfa and set the appropriate start
state.
Signed-off-by: John Johansen <john.johansen@canonical.com>
The dfa is currently setup to be shared (has the basis of refcounting)
but currently can't be because the count can't be increased.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Newer policy encodes more than just version in the version tag,
so add masking to make sure the comparison remains correct.
Note: this is fully compatible with older policy as it will never set
the bits being masked out.
Signed-off-by: John Johansen <john.johansen@canonical.com>
When possible its better to name a learning profile after the missing
profile in question. This allows for both more informative names and
for profile reuse.
Signed-off-by: John Johansen <john.johansen@canonical.com>
prepare_ns() will need to be called from alternate views, and namespaces
will need to be created via different interfaces. So refactor and
allow specifying the view ns.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Rename to indicate the test is only about whether path mediation is used,
not whether other types of mediation might be used.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Policy namespaces will be diverging from profile management and
expanding so put it in its own file.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Prepare to mark sensitive kernel structures for randomization by making
sure they're using designated initializers. These were identified during
allyesconfig builds of x86, arm, and arm64, with most initializer fixes
extracted from grsecurity.
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: John Johansen <john.johansen@canonical.com>
Calling kmalloc(GFP_NOIO) with order == PAGE_ALLOC_COSTLY_ORDER is not
recommended because it might fall into infinite retry loop without
invoking the OOM killer.
Since aa_dfa_unpack() is the only caller of kvzalloc() and
aa_dfa_unpack() which is calling kvzalloc() via unpack_table() is
doing kzalloc(GFP_KERNEL), it is safe to use GFP_KERNEL from
__aa_kvmalloc().
Since aa_simple_write_to_buffer() is the only caller of kvmalloc()
and aa_simple_write_to_buffer() is calling copy_from_user() which
is GFP_KERNEL context (see memdup_user_nul()), it is safe to use
GFP_KERNEL from __aa_kvmalloc().
Therefore, replace GFP_NOIO with GFP_KERNEL. Also, since we have
vmalloc() fallback, add __GFP_NORETRY so that we don't invoke the OOM
killer by kmalloc(GFP_KERNEL) with order == PAGE_ALLOC_COSTLY_ORDER.
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: John Johansen <john.johansen@canonical.com>
For some obscure reason apparmor thinks its needs to locally implement
kref primitives that already exist. Stop doing this.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
As reported by yangshukui, a permission denial from security_task_wait()
can lead to a soft lockup in zap_pid_ns_processes() since it only expects
sys_wait4() to return 0 or -ECHILD. Further, security_task_wait() can
in general lead to zombies; in the absence of some way to automatically
reparent a child process upon a denial, the hook is not useful. Remove
the security hook and its implementations in SELinux and Smack. Smack
already removed its check from its hook.
Reported-by: yangshukui <yangshukui@huawei.com>
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Several of the extended socket classes introduced by
commit da69a5306a ("selinux: support distinctions
among all network address families") are never used because
sockets can never be created with the associated address family.
Remove these unused socket security classes. The removed classes
are bridge_socket for PF_BRIDGE, ib_socket for PF_IB, and mpls_socket
for PF_MPLS.
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Paul Moore <paul@paul-moore.com>
The access to fd from anon_inode is always failed because there is
no set xattr operations. So this patch fixes to ignore private
inode including anon_inode for file functions.
It was only ignored for smack_file_receive() to share dma-buf fd,
but dma-buf has other functions like ioctl and mmap.
Reference: https://lkml.org/lkml/2015/4/17/16
Signed-off-by: Seung-Woo Kim <sw0312.kim@samsung.com>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Since 4b936885a (v2.6.32) all inodes on sockfs and pipefs are disconnected.
It caused filesystem specific code in smack_d_instantiate to be skipped,
because all inodes on those pseudo filesystems were treated as root inodes.
As a result all sockfs inodes had the Smack label set to floor.
In most cases access checks for sockets use socket_smack data so the inode
label is not important. But there are special cases that were broken.
One example would be calling fcntl with F_SETOWN command on a socket fd.
Now smack_d_instantiate expects all pipefs and sockfs inodes to be
disconnected and has the logic in appropriate place.
Signed-off-by: Rafal Krypa <r.krypa@samsung.com>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
smack_file_open() is first checking the capability of calling subject,
this check will skip the SMACK logging for success case. Use smk_tskacc()
for proper logging and SMACK access check.
Signed-off-by: Himanshu Shukla <himanshu.sh@samsung.com>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
In smack_from_secattr function,"smack_known_list" is being traversed
using list_for_each_entry macro, although it is a rcu protected
structure. So it should be traversed using "list_for_each_entry_rcu"
macro to fetch the rcu protected entry.
Signed-off-by: Vishal Goel <vishal.goel@samsung.com>
Signed-off-by: Himanshu Shukla <himanshu.sh@samsung.com>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
There is race condition issue while freeing the i_security blob in SMACK
module. There is existing condition where i_security can be freed while
inode_permission is called from path lookup on second CPU. There has been
observed the page fault with such condition. VFS code and Selinux module
takes care of this condition by freeing the inode and i_security field
using RCU via call_rcu(). But in SMACK directly the i_secuirty blob is
being freed. Use call_rcu() to fix this race condition issue.
Signed-off-by: Himanshu Shukla <himanshu.sh@samsung.com>
Signed-off-by: Vishal Goel <vishal.goel@samsung.com>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
smk_copy_rules() and smk_copy_relabel() are initializing list_head though
they have been initialized already in new_task_smack() function. Delete
repeated initialization.
Signed-off-by: Himanshu Shukla <himanshu.sh@samsung.com>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
"smk_set_access()" function adds a new rule entry in subject label specific
list(rule_list) and in global rule list(smack_rule_list) both. Mutex lock
(rule_lock) is used to avoid simultaneous updates. But this lock is subject
label specific lock. If 2 processes tries to add different rules(i.e with
different subject labels) simultaneously, then both the processes can take
the "rule_lock" respectively. So it will cause a problem while adding
entries in master rule list.
Now a new mutex lock(smack_master_list_lock) has been taken to add entry in
smack_rule_list to avoid simultaneous updates of different rules.
Signed-off-by: Vishal Goel <vishal.goel@samsung.com>
Signed-off-by: Himanshu Shukla <himanshu.sh@samsung.com>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Fix the issue of wrong SMACK label (SMACK64IPIN) update when a second bind
call is made to same IP address & port, but with different SMACK label
(SMACK64IPIN) by second instance of server. In this case server returns
with "Bind:Address already in use" error but before returning, SMACK label
is updated in SMACK port-label mapping list inside smack_socket_bind() hook
To fix this issue a new check has been added in smk_ipv6_port_label()
function before updating the existing port entry. It checks whether the
socket for matching port entry is closed or not. If it is closed then it
means port is not bound and it is safe to update the existing port entry
else return if port is still getting used. For checking whether socket is
closed or not, one more field "smk_can_reuse" has been added in the
"smk_port_label" structure. This field will be set to '1' in
"smack_sk_free_security()" function which is called to free the socket
security blob when the socket is being closed. In this function, port entry
is searched in the SMACK port-label mapping list for the closing socket.
If entry is found then "smk_can_reuse" field is set to '1'.Initially
"smk_can_reuse" field is set to '0' in smk_ipv6_port_label() function after
creating a new entry in the list which indicates that socket is in use.
Signed-off-by: Vishal Goel <vishal.goel@samsung.com>
Signed-off-by: Himanshu Shukla <himanshu.sh@samsung.com>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Permission denied error comes when 2 IPv6 servers are running and client
tries to connect one of them. Scenario is that both servers are using same
IP and port but different protocols(Udp and tcp). They are using different
SMACK64IPIN labels.Tcp server is using "test" and udp server is using
"test-in". When we try to run tcp client with SMACK64IPOUT label as "test",
then connection denied error comes. It should not happen since both tcp
server and client labels are same.This happens because there is no check
for protocol in smk_ipv6_port_label() function while searching for the
earlier port entry. It checks whether there is an existing port entry on
the basis of port only. So it updates the earlier port entry in the list.
Due to which smack label gets changed for earlier entry in the
"smk_ipv6_port_list" list and permission denied error comes.
Now a check is added for socket type also.Now if 2 processes use same
port but different protocols (tcp or udp), then 2 different port entries
will be added in the list. Similarly while checking smack access in
smk_ipv6_port_check() function, port entry is searched on the basis of
both port and protocol.
Signed-off-by: Vishal Goel <vishal.goel@samsung.com>
Signed-off-by: Himanshu Shukla <Himanshu.sh@samsung.com>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Add the rcu synchronization mechanism for accessing smk_ipv6_port_list
in smack IPv6 hooks. Access to the port list is vulnerable to a race
condition issue,it does not apply proper synchronization methods while
working on critical section. It is possible that when one thread is
reading the list, at the same time another thread is modifying the
same port list, which can cause the major problems.
To ensure proper synchronization between two threads, rcu mechanism
has been applied while accessing and modifying the port list. RCU will
also not affect the performance, as there are more accesses than
modification where RCU is most effective synchronization mechanism.
Signed-off-by: Vishal Goel <vishal.goel@samsung.com>
Signed-off-by: Himanshu Shukla <himanshu.sh@samsung.com>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Use SECINITSID_SECURITY as the default SID for booleans which don't have
a matching SID returned from security_genfs_sid(), also update the
error message to a warning which matches this.
This prevents the policy failing to load (and consequently the system
failing to boot) when there is no default genfscon statement matched for
the selinuxfs in the new policy.
Signed-off-by: Gary Tierney <gary.tierney@gmx.com>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Adds error logging to the code paths which can fail when loading a new
policy in sel_write_load(). If the policy fails to be loaded from
userspace then a warning message is printed, whereas if a failure occurs
after loading policy from userspace an error message will be printed
with details on where policy loading failed (recreating one of /classes/,
/policy_capabilities/, /booleans/ in the SELinux fs).
Also, if sel_make_bools() fails to obtain an SID for an entry in
/booleans/* an error will be printed indicating the path of the
boolean.
Signed-off-by: Gary Tierney <gary.tierney@gmx.com>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Processes can only alter their own security attributes via
/proc/pid/attr nodes. This is presently enforced by each individual
security module and is also imposed by the Linux credentials
implementation, which only allows a task to alter its own credentials.
Move the check enforcing this restriction from the individual
security modules to proc_pid_attr_write() before calling the security hook,
and drop the unnecessary task argument to the security hook since it can
only ever be the current task.
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Acked-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
SELinux was sometimes using the task "objective" credentials when
it could/should use the "subjective" credentials. This was sometimes
hidden by the fact that we were unnecessarily passing around pointers
to the current task, making it appear as if the task could be something
other than current, so eliminate all such passing of current. Inline
various permission checking helper functions that can be reduced to a
single avc_has_perm() call.
Since the credentials infrastructure only allows a task to alter
its own credentials, we can always assume that current must be the same
as the target task in selinux_setprocattr after the check. We likely
should move this check from selinux_setprocattr() to proc_pid_attr_write()
and drop the task argument to the security hook altogether; it can only
serve to confuse things.
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Paul Moore <paul@paul-moore.com>
commit aad82892af ("selinux: Add support for
unprivileged mounts from user namespaces") prohibited any use of context
mount options within non-init user namespaces. However, this breaks
use of context mount options for tmpfs mounts within user namespaces,
which are being used by Docker/runc. There is no reason to block such
usage for tmpfs, ramfs or devpts. Exempt these filesystem types
from this restriction.
Before:
sh$ userns_child_exec -p -m -U -M '0 1000 1' -G '0 1000 1' bash
sh# mount -t tmpfs -o context=system_u:object_r:user_tmp_t:s0:c13 none /tmp
mount: tmpfs is write-protected, mounting read-only
mount: cannot mount tmpfs read-only
After:
sh$ userns_child_exec -p -m -U -M '0 1000 1' -G '0 1000 1' bash
sh# mount -t tmpfs -o context=system_u:object_r:user_tmp_t:s0:c13 none /tmp
sh# ls -Zd /tmp
unconfined_u:object_r:user_tmp_t:s0:c13 /tmp
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Paul Moore <paul@paul-moore.com>
commit 79c8b348f215 ("selinux: support distinctions among all network
address families") mapped datagram ICMP sockets to the new icmp_socket
security class, but left ICMPv6 sockets unchanged. This change fixes
that oversight to handle both kinds of sockets consistently.
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Since kernel 4.1 ftrace is supported as a new separate filesystem. It
gets automatically mounted by the kernel under the old path
/sys/kernel/debug/tracing. Because it lives now on a separate filesystem
SELinux needs to be updated to also support setting SELinux labels
on tracefs inodes. This is required for compatibility in Android
when moving to Linux 4.1 or newer.
Signed-off-by: Yongqin Liu <yongqin.liu@linaro.org>
Signed-off-by: William Roberts <william.c.roberts@intel.com>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Extend SELinux to support distinctions among all network address families
implemented by the kernel by defining new socket security classes
and mapping to them. Otherwise, many sockets are mapped to the generic
socket class and are indistinguishable in policy. This has come up
previously with regard to selectively allowing access to bluetooth sockets,
and more recently with regard to selectively allowing access to AF_ALG
sockets. Guido Trentalancia submitted a patch that took a similar approach
to add only support for distinguishing AF_ALG sockets, but this generalizes
his approach to handle all address families implemented by the kernel.
Socket security classes are also added for ICMP and SCTP sockets.
Socket security classes were not defined for AF_* values that are reserved
but unimplemented in the kernel, e.g. AF_NETBEUI, AF_SECURITY, AF_ASH,
AF_ECONET, AF_SNA, AF_WANPIPE.
Backward compatibility is provided by only enabling the finer-grained
socket classes if a new policy capability is set in the policy; older
policies will behave as before. The legacy redhat1 policy capability
that was only ever used in testing within Fedora for ptrace_child
is reclaimed for this purpose; as far as I can tell, this policy
capability is not enabled in any supported distro policy.
Add a pair of conditional compilation guards to detect when new AF_* values
are added so that we can update SELinux accordingly rather than having to
belatedly update it long after new address families are introduced.
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Paul Moore <paul@paul-moore.com>
This was entirely automated, using the script by Al:
PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*<asm/uaccess.h>'
sed -i -e "s!$PATT!#include <linux/uaccess.h>!" \
$(git grep -l "$PATT"|grep -v ^include/linux/uaccess.h)
to do the replacement at the end of the merge window.
Requested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull SElinux fix from James Morris:
"From Paul:
'A small SELinux patch to fix some clang/llvm compiler warnings and
ensure the tools under scripts work well in the face of kernel
changes'"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security:
selinux: use the kernel headers when building scripts/selinux
Commit 3322d0d64f ("selinux: keep SELinux in sync with new capability
definitions") added a check on the defined capabilities without
explicitly including the capability header file which caused problems
when building genheaders for users of clang/llvm. Resolve this by
using the kernel headers when building genheaders, which is arguably
the right thing to do regardless, and explicitly including the
kernel's capability.h header file in classmap.h. We also update the
mdp build, even though it wasn't causing an error we really should
be using the headers from the kernel we are building.
Reported-by: Nicolas Iooss <nicolas.iooss@m4x.org>
Signed-off-by: Paul Moore <paul@paul-moore.com>
For remote attestion it is important for the ima measurement values to
be platform-independent. Therefore integer fields to be hashed must be
converted to canonical format.
Link: http://lkml.kernel.org/r/1480554346-29071-11-git-send-email-zohar@linux.vnet.ibm.com
Signed-off-by: Andreas Steffen <andreas.steffen@strongswan.org>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Cc: Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Dmitry Kasatkin <dmitry.kasatkin@gmail.com>
Cc: Josh Sklar <sklar@linux.vnet.ibm.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Stewart Smith <stewart@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The IMA binary_runtime_measurements list is currently in platform native
format.
To allow restoring a measurement list carried across kexec with a
different endianness than the targeted kernel, this patch defines
little-endian as the canonical format. For big endian systems wanting
to save/restore the measurement list from a system with a different
endianness, a new boot command line parameter named "ima_canonical_fmt"
is defined.
Considerations: use of the "ima_canonical_fmt" boot command line option
will break existing userspace applications on big endian systems
expecting the binary_runtime_measurements list to be in platform native
format.
Link: http://lkml.kernel.org/r/1480554346-29071-10-git-send-email-zohar@linux.vnet.ibm.com
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Acked-by: Dmitry Kasatkin <dmitry.kasatkin@gmail.com>
Cc: Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Andreas Steffen <andreas.steffen@strongswan.org>
Cc: Josh Sklar <sklar@linux.vnet.ibm.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Stewart Smith <stewart@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The configured IMA measurement list template format can be replaced at
runtime on the boot command line, including a custom template format.
This patch adds support for restoring a measuremement list containing
multiple builtin/custom template formats.
Link: http://lkml.kernel.org/r/1480554346-29071-9-git-send-email-zohar@linux.vnet.ibm.com
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Acked-by: Dmitry Kasatkin <dmitry.kasatkin@gmail.com>
Cc: Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Andreas Steffen <andreas.steffen@strongswan.org>
Cc: Josh Sklar <sklar@linux.vnet.ibm.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Stewart Smith <stewart@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The builtin and single custom templates are currently stored in an
array. In preparation for being able to restore a measurement list
containing multiple builtin/custom templates, this patch stores the
builtin and custom templates as a linked list. This will permit
defining more than one custom template per boot.
Link: http://lkml.kernel.org/r/1480554346-29071-8-git-send-email-zohar@linux.vnet.ibm.com
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Acked-by: Dmitry Kasatkin <dmitry.kasatkin@gmail.com>
Cc: Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Andreas Steffen <andreas.steffen@strongswan.org>
Cc: Josh Sklar <sklar@linux.vnet.ibm.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Stewart Smith <stewart@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The TPM PCRs are only reset on a hard reboot. In order to validate a
TPM's quote after a soft reboot (eg. kexec -e), the IMA measurement
list of the running kernel must be saved and restored on boot.
This patch uses the kexec buffer passing mechanism to pass the
serialized IMA binary_runtime_measurements to the next kernel.
Link: http://lkml.kernel.org/r/1480554346-29071-7-git-send-email-zohar@linux.vnet.ibm.com
Signed-off-by: Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: Dmitry Kasatkin <dmitry.kasatkin@gmail.com>
Cc: Andreas Steffen <andreas.steffen@strongswan.org>
Cc: Josh Sklar <sklar@linux.vnet.ibm.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Stewart Smith <stewart@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In preparation for serializing the binary_runtime_measurements, this
patch maintains the amount of memory required.
Link: http://lkml.kernel.org/r/1480554346-29071-5-git-send-email-zohar@linux.vnet.ibm.com
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Acked-by: Dmitry Kasatkin <dmitry.kasatkin@gmail.com>
Cc: Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Andreas Steffen <andreas.steffen@strongswan.org>
Cc: Josh Sklar <sklar@linux.vnet.ibm.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Stewart Smith <stewart@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Measurements carried across kexec need to be added to the IMA
measurement list, but should not prevent measurements of the newly
booted kernel from being added to the measurement list. This patch adds
support for allowing duplicate measurements.
The "boot_aggregate" measurement entry is the delimiter between soft
boots.
Link: http://lkml.kernel.org/r/1480554346-29071-4-git-send-email-zohar@linux.vnet.ibm.com
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Acked-by: Dmitry Kasatkin <dmitry.kasatkin@gmail.com>
Cc: Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Andreas Steffen <andreas.steffen@strongswan.org>
Cc: Josh Sklar <sklar@linux.vnet.ibm.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Stewart Smith <stewart@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The TPM PCRs are only reset on a hard reboot. In order to validate a
TPM's quote after a soft reboot (eg. kexec -e), the IMA measurement
list of the running kernel must be saved and restored on boot. This
patch restores the measurement list.
Link: http://lkml.kernel.org/r/1480554346-29071-3-git-send-email-zohar@linux.vnet.ibm.com
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Acked-by: Dmitry Kasatkin <dmitry.kasatkin@gmail.com>
Cc: Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Andreas Steffen <andreas.steffen@strongswan.org>
Cc: Josh Sklar <sklar@linux.vnet.ibm.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Stewart Smith <stewart@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull vfs updates from Al Viro:
- more ->d_init() stuff (work.dcache)
- pathname resolution cleanups (work.namei)
- a few missing iov_iter primitives - copy_from_iter_full() and
friends. Either copy the full requested amount, advance the iterator
and return true, or fail, return false and do _not_ advance the
iterator. Quite a few open-coded callers converted (and became more
readable and harder to fuck up that way) (work.iov_iter)
- several assorted patches, the big one being logfs removal
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
logfs: remove from tree
vfs: fix put_compat_statfs64() does not handle errors
namei: fold should_follow_link() with the step into not-followed link
namei: pass both WALK_GET and WALK_MORE to should_follow_link()
namei: invert WALK_PUT logics
namei: shift interpretation of LOOKUP_FOLLOW inside should_follow_link()
namei: saner calling conventions for mountpoint_last()
namei.c: get rid of user_path_parent()
switch getfrag callbacks to ..._full() primitives
make skb_add_data,{_nocache}() and skb_copy_to_page_nocache() advance only on success
[iov_iter] new primitives - copy_from_iter_full() and friends
don't open-code file_inode()
ceph: switch to use of ->d_init()
ceph: unify dentry_operations instances
lustre: switch to use of ->d_init()
Merge more updates from Andrew Morton:
- a few misc things
- kexec updates
- DMA-mapping updates to better support networking DMA operations
- IPC updates
- various MM changes to improve DAX fault handling
- lots of radix-tree changes, mainly to the test suite. All leading up
to reimplementing the IDA/IDR code to be a wrapper layer over the
radix-tree. However the final trigger-pulling patch is held off for
4.11.
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (114 commits)
radix tree test suite: delete unused rcupdate.c
radix tree test suite: add new tag check
radix-tree: ensure counts are initialised
radix tree test suite: cache recently freed objects
radix tree test suite: add some more functionality
idr: reduce the number of bits per level from 8 to 6
rxrpc: abstract away knowledge of IDR internals
tpm: use idr_find(), not idr_find_slowpath()
idr: add ida_is_empty
radix tree test suite: check multiorder iteration
radix-tree: fix replacement for multiorder entries
radix-tree: add radix_tree_split_preload()
radix-tree: add radix_tree_split
radix-tree: add radix_tree_join
radix-tree: delete radix_tree_range_tag_if_tagged()
radix-tree: delete radix_tree_locate_item()
radix-tree: improve multiorder iterators
btrfs: fix race in btrfs_free_dummy_fs_info()
radix-tree: improve dump output
radix-tree: make radix_tree_find_next_bit more useful
...
Patch series "mm: unexport __get_user_pages_unlocked()".
This patch series continues the cleanup of get_user_pages*() functions
taking advantage of the fact we can now pass gup_flags as we please.
It firstly adds an additional 'locked' parameter to
get_user_pages_remote() to allow for its callers to utilise
VM_FAULT_RETRY functionality. This is necessary as the invocation of
__get_user_pages_unlocked() in process_vm_rw_single_vec() makes use of
this and no other existing higher level function would allow it to do
so.
Secondly existing callers of __get_user_pages_unlocked() are replaced
with the appropriate higher-level replacement -
get_user_pages_unlocked() if the current task and memory descriptor are
referenced, or get_user_pages_remote() if other task/memory descriptors
are referenced (having acquiring mmap_sem.)
This patch (of 2):
Add a int *locked parameter to get_user_pages_remote() to allow
VM_FAULT_RETRY faulting behaviour similar to get_user_pages_[un]locked().
Taking into account the previous adjustments to get_user_pages*()
functions allowing for the passing of gup_flags, we are now in a
position where __get_user_pages_unlocked() need only be exported for his
ability to allow VM_FAULT_RETRY behaviour, this adjustment allows us to
subsequently unexport __get_user_pages_unlocked() as well as allowing
for future flexibility in the use of get_user_pages_remote().
[sfr@canb.auug.org.au: merge fix for get_user_pages_remote API change]
Link: http://lkml.kernel.org/r/20161122210511.024ec341@canb.auug.org.au
Link: http://lkml.kernel.org/r/20161027095141.2569-2-lstoakes@gmail.com
Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Hugh Dickins <hughd@google.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krcmar <rkrcmar@redhat.com>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull namespace updates from Eric Biederman:
"After a lot of discussion and work we have finally reachanged a basic
understanding of what is necessary to make unprivileged mounts safe in
the presence of EVM and IMA xattrs which the last commit in this
series reflects. While technically it is a revert the comments it adds
are important for people not getting confused in the future. Clearing
up that confusion allows us to seriously work on unprivileged mounts
of fuse in the next development cycle.
The rest of the fixes in this set are in the intersection of user
namespaces, ptrace, and exec. I started with the first fix which
started a feedback cycle of finding additional issues during review
and fixing them. Culiminating in a fix for a bug that has been present
since at least Linux v1.0.
Potentially these fixes were candidates for being merged during the rc
cycle, and are certainly backport candidates but enough little things
turned up during review and testing that I decided they should be
handled as part of the normal development process just to be certain
there were not any great surprises when it came time to backport some
of these fixes"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
Revert "evm: Translate user/group ids relative to s_user_ns when computing HMAC"
exec: Ensure mm->user_ns contains the execed files
ptrace: Don't allow accessing an undumpable mm
ptrace: Capture the ptracer's creds not PT_PTRACE_CAP
mm: Add a user_ns owner to mm_struct and fix ptrace permission checks
Pull security subsystem updates from James Morris:
"Generally pretty quiet for this release. Highlights:
Yama:
- allow ptrace access for original parent after re-parenting
TPM:
- add documentation
- many bugfixes & cleanups
- define a generic open() method for ascii & bios measurements
Integrity:
- Harden against malformed xattrs
SELinux:
- bugfixes & cleanups
Smack:
- Remove unnecessary smack_known_invalid label
- Do not apply star label in smack_setprocattr hook
- parse mnt opts after privileges check (fixes unpriv DoS vuln)"
* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security: (56 commits)
Yama: allow access for the current ptrace parent
tpm: adjust return value of tpm_read_log
tpm: vtpm_proxy: conditionally call tpm_chip_unregister
tpm: Fix handling of missing event log
tpm: Check the bios_dir entry for NULL before accessing it
tpm: return -ENODEV if np is not set
tpm: cleanup of printk error messages
tpm: replace of_find_node_by_name() with dev of_node property
tpm: redefine read_log() to handle ACPI/OF at runtime
tpm: fix the missing .owner in tpm_bios_measurements_ops
tpm: have event log use the tpm_chip
tpm: drop tpm1_chip_register(/unregister)
tpm: replace dynamically allocated bios_dir with a static array
tpm: replace symbolic permission with octal for securityfs files
char: tpm: fix kerneldoc tpm2_unseal_trusted name typo
tpm_tis: Allow tpm_tis to be bound using DT
tpm, tpm_vtpm_proxy: add kdoc comments for VTPM_PROXY_IOC_NEW_DEV
tpm: Only call pm_runtime_get_sync if device has a parent
tpm: define a generic open() method for ascii & bios measurements
Documentation: tpm: add the Physical TPM device tree binding documentation
...
Pull timer updates from Thomas Gleixner:
"The time/timekeeping/timer folks deliver with this update:
- Fix a reintroduced signed/unsigned issue and cleanup the whole
signed/unsigned mess in the timekeeping core so this wont happen
accidentaly again.
- Add a new trace clock based on boot time
- Prevent injection of random sleep times when PM tracing abuses the
RTC for storage
- Make posix timers configurable for real tiny systems
- Add tracepoints for the alarm timer subsystem so timer based
suspend wakeups can be instrumented
- The usual pile of fixes and updates to core and drivers"
* 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (23 commits)
timekeeping: Use mul_u64_u32_shr() instead of open coding it
timekeeping: Get rid of pointless typecasts
timekeeping: Make the conversion call chain consistently unsigned
timekeeping_Force_unsigned_clocksource_to_nanoseconds_conversion
alarmtimer: Add tracepoints for alarm timers
trace: Update documentation for mono, mono_raw and boot clock
trace: Add an option for boot clock as trace clock
timekeeping: Add a fast and NMI safe boot clock
timekeeping/clocksource_cyc2ns: Document intended range limitation
timekeeping: Ignore the bogus sleep time if pm_trace is enabled
selftests/timers: Fix spelling mistake "Asyncrhonous" -> "Asynchronous"
clocksource/drivers/bcm2835_timer: Unmap region obtained by of_iomap
clocksource/drivers/arm_arch_timer: Map frame with of_io_request_and_map()
arm64: dts: rockchip: Arch counter doesn't tick in system suspend
clocksource/drivers/arm_arch_timer: Don't assume clock runs in suspend
posix-timers: Make them configurable
posix_cpu_timers: Move the add_device_randomness() call to a proper place
timer: Move sys_alarm from timer.c to itimer.c
ptp_clock: Allow for it to be optional
Kconfig: Regenerate *.c_shipped files after previous changes
...
copy_from_iter_full(), copy_from_iter_full_nocache() and
csum_and_copy_from_iter_full() - counterparts of copy_from_iter()
et.al., advancing iterator only in case of successful full copy
and returning whether it had been successful or not.
Convert some obvious users. *NOTE* - do not blindly assume that
something is a good candidate for those unless you are sure that
not advancing iov_iter in failure case is the right thing in
this case. Anything that does short read/short write kind of
stuff (or is in a loop, etc.) is unlikely to be a good one.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Under ptrace_scope=1, it's possible to have a tracee that is already
ptrace-attached, but is no longer a direct descendant. For instance, a
forking daemon will be re-parented to init, losing its ancestry to the
tracer that launched it.
The tracer can continue using ptrace in that state, but it will be
denied other accesses that check PTRACE_MODE_ATTACH, like process_vm_rw
and various procfs files. There's no reason to prevent such access for
a tracer that already has ptrace control anyway.
This patch adds a case to ptracer_exception_found to allow access for
any task in the same thread group as the current ptrace parent.
Signed-off-by: Josh Stone <jistone@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: James Morris <james.l.morris@oracle.com>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: linux-security-module@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: James Morris <james.l.morris@oracle.com>
This reverts commit 0b3c9761d1.
Seth Forshee <seth.forshee@canonical.com> writes:
> All right, I think 0b3c9761d1 should be
> reverted then. EVM is a machine-local integrity mechanism, and so it
> makes sense that the signature would be based on the kernel's notion of
> the uid and not the filesystem's.
I added a commment explaining why the EVM hmac needs to be in the
kernel's notion of uid and gid, not the filesystems to prevent
remounting the filesystem and gaining unwaranted trust in files.
Acked-by: Seth Forshee <seth.forshee@canonical.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Convert isec->lock from a mutex into a spinlock. Instead of holding
the lock while sleeping in inode_doinit_with_dentry, set
isec->initialized to LABEL_PENDING and release the lock. Then, when
the sid has been determined, re-acquire the lock. If isec->initialized
is still set to LABEL_PENDING, set isec->sid; otherwise, the sid has
been set by another task (LABEL_INITIALIZED) or invalidated
(LABEL_INVALID) in the meantime.
This fixes a deadlock on gfs2 where
* one task is in inode_doinit_with_dentry -> gfs2_getxattr, holds
isec->lock, and tries to acquire the inode's glock, and
* another task is in do_xmote -> inode_go_inval ->
selinux_inode_invalidate_secctx, holds the inode's glock, and
tries to acquire isec->lock.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
[PM: minor tweaks to keep checkpatch.pl happy]
Signed-off-by: Paul Moore <paul@paul-moore.com>
When a new capability is defined, SELinux needs to be updated.
Trigger a build error if a new capability is defined without
corresponding update to security/selinux/include/classmap.h's
COMMON_CAP2_PERMS. This is similar to BUILD_BUG_ON() guards
in the SELinux nlmsgtab code to ensure that SELinux tracks
new netlink message types as needed.
Note that there is already a similar build guard in
security/selinux/hooks.c to detect when more than 64
capabilities are defined, since that will require adding
a third capability class to SELinux.
A nicer way to do this would be to extend scripts/selinux/genheaders
or a similar tool to auto-generate the necessary definitions and code
for SELinux capability checking from include/uapi/linux/capability.h.
AppArmor does something similar in its Makefile, although it only
needs to generate a single table of names. That is left as future
work.
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
[PM: reformat the description to keep checkpatch.pl happy]
Signed-off-by: Paul Moore <paul@paul-moore.com>
After a policy replacement, the task cred may be out of date and need
to be updated. However change_hat is using the stale profiles from
the out of date cred resulting in either: a stale profile being applied
or, incorrect failure when searching for a hat profile as it has been
migrated to the new parent profile.
Fixes: 01e2b670aa (failure to find hat)
Fixes: 898127c34e (stale policy being applied)
Bugzilla: https://bugzilla.suse.com/show_bug.cgi?id=1000287
Cc: stable@vger.kernel.org
Signed-off-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
At present, one can write any signed integer value to
/sys/fs/selinux/enforce and it will be stored,
e.g. echo -1 > /sys/fs/selinux/enforce or echo 2 >
/sys/fs/selinux/enforce. This makes no real difference
to the kernel, since it only ever cares if it is zero or non-zero,
but some userspace code compares it with 1 to decide if SELinux
is enforcing, and this could confuse it. Only a process that is
already root and is allowed the setenforce permission in SELinux
policy can write to /sys/fs/selinux/enforce, so this is not considered
to be a security issue, but it should be fixed.
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Some embedded systems have no use for them. This removes about
25KB from the kernel binary size when configured out.
Corresponding syscalls are routed to a stub logging the attempt to
use those syscalls which should be enough of a clue if they were
disabled without proper consideration. They are: timer_create,
timer_gettime: timer_getoverrun, timer_settime, timer_delete,
clock_adjtime, setitimer, getitimer, alarm.
The clock_settime, clock_gettime, clock_getres and clock_nanosleep
syscalls are replaced by simple wrappers compatible with CLOCK_REALTIME,
CLOCK_MONOTONIC and CLOCK_BOOTTIME only which should cover the vast
majority of use cases with very little code.
Signed-off-by: Nicolas Pitre <nico@linaro.org>
Acked-by: Richard Cochran <richardcochran@gmail.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: John Stultz <john.stultz@linaro.org>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Cc: Paul Bolle <pebolle@tiscali.nl>
Cc: linux-kbuild@vger.kernel.org
Cc: netdev@vger.kernel.org
Cc: Michal Marek <mmarek@suse.com>
Cc: Edward Cree <ecree@solarflare.com>
Link: http://lkml.kernel.org/r/1478841010-28605-7-git-send-email-nicolas.pitre@linaro.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
The invalid Smack label ("") and the Huh ("?") Smack label
serve the same purpose and having both is unnecessary.
While pulling out the invalid label it became clear that
the use of smack_from_secid() was inconsistent, so that
is repaired. The setting of inode labels to the invalid
label could never happen in a functional system, has
never been observed in the wild and is not what you'd
really want for a failure behavior in any case. That is
removed.
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Since smack_parse_opts_str() is calling match_strdup() which uses
GFP_KERNEL, it is safe to use GFP_KERNEL from kcalloc() which is
called by smack_parse_opts_str().
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Now that isec->initialized == LABEL_INITIALIZED implies that
isec->sclass is valid, skip such inodes immediately in
inode_doinit_with_dentry.
For the remaining inodes, initialize isec->sclass at the beginning of
inode_doinit_with_dentry to simplify the code.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Pass the file mode of the proc inode to be created to
proc_pid_make_inode. In proc_pid_make_inode, initialize inode->i_mode
before calling security_task_to_inode. This allows selinux to set
isec->sclass right away without introducing "half-initialized" inode
security structs.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Fix the comment for function __inode_security_revalidate, which returns
an integer.
Use the LABEL_* constants consistently for isec->initialized.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Since selinux_parse_opts_str() is calling match_strdup() which uses
GFP_KERNEL, it is safe to use GFP_KERNEL from kcalloc() which is
called by selinux_parse_opts_str().
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Paul Moore <paul@paul-moore.com>
In general the handling of IMA/EVM xattrs is good, but I found
a few locations where either the xattr size or the value of the
type field in the xattr are not checked. Add a few simple checks
to these locations to prevent malformed or malicious xattrs from
causing problems.
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Userspace applications have been modified to write security xattrs,
but they are not context aware. In the case of security.ima, the
security xattr can be either a file hash or a file signature.
Permitting writing one, but not the other requires the application to
be context aware.
In addition, userspace applications might write files to a staging
area, which might not be in policy, and then change some file metadata
(eg. owner) making it in policy. As a result, these files are not
labeled properly.
This reverts commit c68ed80c97, which
prevents writing file hashes as security.ima xattrs.
Requested-by: Patrick Ohly <patrick.ohly@intel.com>
Cc: Dmitry Kasatkin <dmitry.kasatkin@gmail.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
When the "policy" securityfs file is opened for read, it is opened as a
sequential file. However, when it is eventually released, there is no
cleanup for the sequential file, therefore some memory is leaked.
This patch adds a call to seq_release() in ima_release_policy() to clean up
the memory when the file is opened for read.
Fixes: 80eae209d6 IMA: allow reading back the current policy
Reported-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Eric Richter <erichte@linux.vnet.ibm.com>
Tested-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
The check for a deleted entry in the list of IPv6 host
addresses was being performed in the wrong place, leading
to most peculiar results in some cases. This puts the
check into the right place.
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Memory leak in smack_cred_prepare()function.
smack_cred_prepare() hook returns error if there is error in allocating
memory in smk_copy_rules() or smk_copy_relabel() function.
If smack_cred_prepare() function returns error then the calling
function should call smack_cred_free() function for cleanup.
In smack_cred_free() function first credential is extracted and
then all rules are deleted. In smack_cred_prepare() function security
field is assigned in the end when all function return success. But this
function may return before and memory will not be freed.
Signed-off-by: Himanshu Shukla <himanshu.sh@samsung.com>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Smack prohibits processes from using the star ("*") and web ("@") labels.
Checks have been added in other functions. In smack_setprocattr()
hook, only check for web ("@") label has been added and restricted
from applying web ("@") label.
Check for star ("*") label should also be added in smack_setprocattr()
hook. Return error should be "-EINVAL" not "-EPERM" as permission
is there for setting label but not the label value as star ("*") or
web ("@").
Signed-off-by: Himanshu Shukla <himanshu.sh@samsung.com>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
In smack_set_mnt_opts()first the SMACK mount options are being
parsed and later it is being checked whether the user calling
mount has CAP_MAC_ADMIN capability.
This sequence of operationis will allow unauthorized user to add
SMACK labels in label list and may cause denial of security attack
by adding many labels by allocating kernel memory by unauthorized user.
Superblock smack flag is also being set as initialized though function
may return with EPERM error.
First check the capability of calling user then set the SMACK attributes
and smk_flags.
Signed-off-by: Himanshu Shukla <himanshu.sh@samsung.com>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Assign smack_known_web label for kernel thread's socket
Creating struct sock by sk_alloc function in various kernel subsystems
like bluetooth doesn't call smack_socket_post_create(). In such case,
received sock label is the floor('_') label and makes access deny.
Signed-off-by: jooseong lee <jooseong.lee@samsung.com>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Since BIG_KEYS can't be compiled as module it requires one of the "stdrng"
providers to be compiled into kernel. Otherwise big_key_crypto_init() fails
on crypto_alloc_rng step and next dereference of big_key_skcipher (e.g. in
big_key_preparse()) results in a NULL pointer dereference.
Fixes: 13100a72f4 ('Security: Keys: Big keys stored encrypted')
Signed-off-by: Artem Savkov <asavkov@redhat.com>
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Stephan Mueller <smueller@chronox.de>
cc: Kirill Marinushkin <k.marinushkin@gmail.com>
cc: stable@vger.kernel.org
Signed-off-by: James Morris <james.l.morris@oracle.com>
big_key has two separate initialisation functions, one that registers the
key type and one that registers the crypto. If the key type fails to
register, there's no problem if the crypto registers successfully because
there's no way to reach the crypto except through the key type.
However, if the key type registers successfully but the crypto does not,
big_key_rng and big_key_blkcipher may end up set to NULL - but the code
neither checks for this nor unregisters the big key key type.
Furthermore, since the key type is registered before the crypto, it is
theoretically possible for the kernel to try adding a big_key before the
crypto is set up, leading to the same effect.
Fix this by merging big_key_crypto_init() and big_key_init() and calling
the resulting function late. If they're going to be encrypted, we
shouldn't be creating big_keys before we have the facilities to do the
encryption available. The key type registration is also moved after the
crypto initialisation.
The fix also includes message printing on failure.
If the big_key type isn't correctly set up, simply doing:
dd if=/dev/zero bs=4096 count=1 | keyctl padd big_key a @s
ought to cause an oops.
Fixes: 13100a72f4 ('Security: Keys: Big keys stored encrypted')
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Peter Hlavaty <zer0mem@yahoo.com>
cc: Kirill Marinushkin <k.marinushkin@gmail.com>
cc: Artem Savkov <asavkov@redhat.com>
cc: stable@vger.kernel.org
Signed-off-by: James Morris <james.l.morris@oracle.com>
This fixes CVE-2016-7042.
Fix a short sprintf buffer in proc_keys_show(). If the gcc stack protector
is turned on, this can cause a panic due to stack corruption.
The problem is that xbuf[] is not big enough to hold a 64-bit timeout
rendered as weeks:
(gdb) p 0xffffffffffffffffULL/(60*60*24*7)
$2 = 30500568904943
That's 14 chars plus NUL, not 11 chars plus NUL.
Expand the buffer to 16 chars.
I think the unpatched code apparently works if the stack-protector is not
enabled because on a 32-bit machine the buffer won't be overflowed and on a
64-bit machine there's a 64-bit aligned pointer at one side and an int that
isn't checked again on the other side.
The panic incurred looks something like:
Kernel panic - not syncing: stack-protector: Kernel stack is corrupted in: ffffffff81352ebe
CPU: 0 PID: 1692 Comm: reproducer Not tainted 4.7.2-201.fc24.x86_64 #1
Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011
0000000000000086 00000000fbbd2679 ffff8800a044bc00 ffffffff813d941f
ffffffff81a28d58 ffff8800a044bc98 ffff8800a044bc88 ffffffff811b2cb6
ffff880000000010 ffff8800a044bc98 ffff8800a044bc30 00000000fbbd2679
Call Trace:
[<ffffffff813d941f>] dump_stack+0x63/0x84
[<ffffffff811b2cb6>] panic+0xde/0x22a
[<ffffffff81352ebe>] ? proc_keys_show+0x3ce/0x3d0
[<ffffffff8109f7f9>] __stack_chk_fail+0x19/0x30
[<ffffffff81352ebe>] proc_keys_show+0x3ce/0x3d0
[<ffffffff81350410>] ? key_validate+0x50/0x50
[<ffffffff8134db30>] ? key_default_cmp+0x20/0x20
[<ffffffff8126b31c>] seq_read+0x2cc/0x390
[<ffffffff812b6b12>] proc_reg_read+0x42/0x70
[<ffffffff81244fc7>] __vfs_read+0x37/0x150
[<ffffffff81357020>] ? security_file_permission+0xa0/0xc0
[<ffffffff81246156>] vfs_read+0x96/0x130
[<ffffffff81247635>] SyS_read+0x55/0xc0
[<ffffffff817eb872>] entry_SYSCALL_64_fastpath+0x1a/0xa4
Reported-by: Ondrej Kozina <okozina@redhat.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: Ondrej Kozina <okozina@redhat.com>
cc: stable@vger.kernel.org
Signed-off-by: James Morris <james.l.morris@oracle.com>
Pull vmap stack fixes from Ingo Molnar:
"This is fallout from CONFIG_HAVE_ARCH_VMAP_STACK=y on x86: stack
accesses that used to be just somewhat questionable are now totally
buggy.
These changes try to do it without breaking the ABI: the fields are
left there, they are just reporting zero, or reporting narrower
information (the maps file change)"
* 'mm-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
mm: Change vm_is_stack_for_task() to vm_is_stack_for_current()
fs/proc: Stop trying to report thread stacks
fs/proc: Stop reporting eip and esp in /proc/PID/stat
mm/numa: Remove duplicated include from mprotect.c
Asking for a non-current task's stack can't be done without races
unless the task is frozen in kernel mode. As far as I know,
vm_is_stack_for_task() never had a safe non-current use case.
The __unused annotation is because some KSTK_ESP implementations
ignore their parameter, which IMO is further justification for this
patch.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Jann Horn <jann@thejh.net>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Linux API <linux-api@vger.kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tycho Andersen <tycho.andersen@canonical.com>
Link: http://lkml.kernel.org/r/4c3f68f426e6c061ca98b4fc7ef85ffbb0a25b0c.1475257877.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This removes the 'write' and 'force' from get_user_pages_remote() and
replaces them with 'gup_flags' to make the use of FOLL_FORCE explicit in
callers as use of this flag can result in surprising behaviour (and
hence bugs) within the mm subsystem.
Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull more vfs updates from Al Viro:
">rename2() work from Miklos + current_time() from Deepa"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
fs: Replace current_fs_time() with current_time()
fs: Replace CURRENT_TIME_SEC with current_time() for inode timestamps
fs: Replace CURRENT_TIME with current_time() for inode timestamps
fs: proc: Delete inode time initializations in proc_alloc_inode()
vfs: Add current_time() api
vfs: add note about i_op->rename changes to porting
fs: rename "rename2" i_op to "rename"
vfs: remove unused i_op->rename
fs: make remaining filesystems use .rename2
libfs: support RENAME_NOREPLACE in simple_rename()
fs: support RENAME_NOREPLACE for local filesystems
ncpfs: fix unused variable warning
Pull vfs xattr updates from Al Viro:
"xattr stuff from Andreas
This completes the switch to xattr_handler ->get()/->set() from
->getxattr/->setxattr/->removexattr"
* 'work.xattr' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
vfs: Remove {get,set,remove}xattr inode operations
xattr: Stop calling {get,set,remove}xattr inode operations
vfs: Check for the IOP_XATTR flag in listxattr
xattr: Add __vfs_{get,set,remove}xattr helpers
libfs: Use IOP_XATTR flag for empty directory handling
vfs: Use IOP_XATTR flag for bad-inode handling
vfs: Add IOP_XATTR inode operations flag
vfs: Move xattr_resolve_name to the front of fs/xattr.c
ecryptfs: Switch to generic xattr handlers
sockfs: Get rid of getxattr iop
sockfs: getxattr: Fail with -EOPNOTSUPP for invalid attribute names
kernfs: Switch to generic xattr handlers
hfs: Switch to generic xattr handlers
jffs2: Remove jffs2_{get,set,remove}xattr macros
xattr: Remove unnecessary NULL attribute name check
Pull misc vfs updates from Al Viro:
"Assorted misc bits and pieces.
There are several single-topic branches left after this (rename2
series from Miklos, current_time series from Deepa Dinamani, xattr
series from Andreas, uaccess stuff from from me) and I'd prefer to
send those separately"
* 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (39 commits)
proc: switch auxv to use of __mem_open()
hpfs: support FIEMAP
cifs: get rid of unused arguments of CIFSSMBWrite()
posix_acl: uapi header split
posix_acl: xattr representation cleanups
fs/aio.c: eliminate redundant loads in put_aio_ring_file
fs/internal.h: add const to ns_dentry_operations declaration
compat: remove compat_printk()
fs/buffer.c: make __getblk_slow() static
proc: unsigned file descriptors
fs/file: more unsigned file descriptors
fs: compat: remove redundant check of nr_segs
cachefiles: Fix attempt to read i_blocks after deleting file [ver #2]
cifs: don't use memcpy() to copy struct iov_iter
get rid of separate multipage fault-in primitives
fs: Avoid premature clearing of capabilities
fs: Give dentry to inode_change_ok() instead of inode
fuse: Propagate dentry down to inode_change_ok()
ceph: Propagate dentry down to inode_change_ok()
xfs: Propagate dentry down to inode_change_ok()
...
Merge my system logging cleanups, triggered by the broken '\n' patches.
The line continuation handling has been broken basically forever, and
the code to handle the system log records was both confusing and
dubious. And it would do entirely the wrong thing unless you always had
a terminating newline, partly because it couldn't actually see whether a
message was marked KERN_CONT or not (but partly because the LOG_CONT
handling in the recording code was rather confusing too).
This re-introduces a real semantically meaningful KERN_CONT, and fixes
the few places I noticed where it was missing. There are probably more
missing cases, since KERN_CONT hasn't actually had any semantic meaning
for at least four years (other than the checkpatch meaning of "no log
level necessary, this is a continuation line").
This also allows the combination of KERN_CONT and a log level. In that
case the log level will be ignored if the merging with a previous line
is successful, but if a new record is needed, that new record will now
get the right log level.
That also means that you can at least in theory combine KERN_CONT with
the "pr_info()" style helpers, although any use of pr_fmt() prefixing
would make that just result in a mess, of course (the prefix would end
up in the middle of a continuing line).
* printk-cleanups:
printk: make reading the kernel log flush pending lines
printk: re-organize log_output() to be more legible
printk: split out core logging code into helper function
printk: reinstate KERN_CONT for printing continuation lines
Long long ago the kernel log buffer was a buffered stream of bytes, very
much like stdio in user space. It supported log levels by scanning the
stream and noticing the log level markers at the beginning of each line,
but if you wanted to print a partial line in multiple chunks, you just
did multiple printk() calls, and it just automatically worked.
Except when it didn't, and you had very confusing output when different
lines got all mixed up with each other. Then you got fragment lines
mixing with each other, or with non-fragment lines, because it was
traditionally impossible to tell whether a printk() call was a
continuation or not.
To at least help clarify the issue of continuation lines, we added a
KERN_CONT marker back in 2007 to mark continuation lines:
4749252776 ("printk: add KERN_CONT annotation").
That continuation marker was initially an empty string, and didn't
actuall make any semantic difference. But it at least made it possible
to annotate the source code, and have check-patch notice that a printk()
didn't need or want a log level marker, because it was a continuation of
a previous line.
To avoid the ambiguity between a continuation line that had that
KERN_CONT marker, and a printk with no level information at all, we then
in 2009 made KERN_CONT be a real log level marker which meant that we
could now reliably tell the difference between the two cases.
5fd29d6ccb ("printk: clean up handling of log-levels and newlines")
and we could take advantage of that to make sure we didn't mix up
continuation lines with lines that just didn't have any loglevel at all.
Then, in 2012, the kernel log buffer was changed to be a "record" based
log, where each line was a record that has a loglevel and a timestamp.
You can see the beginning of that conversion in commits
e11fea92e1 ("kmsg: export printk records to the /dev/kmsg interface")
7ff9554bb5 ("printk: convert byte-buffer to variable-length record buffer")
with a number of follow-up commits to fix some painful fallout from that
conversion. Over all, it took a couple of months to sort out most of
it. But the upside was that you could have concurrent readers (and
writers) of the kernel log and not have lines with mixed output in them.
And one particular pain-point for the record-based kernel logging was
exactly the fragmentary lines that are generated in smaller chunks. In
order to still log them as one recrod, the continuation lines need to be
attached to the previous record properly.
However the explicit continuation record marker that is actually useful
for this exact case was actually removed in aroundm the same time by commit
61e99ab8e3 ("printk: remove the now unnecessary "C" annotation for KERN_CONT")
due to the incorrect belief that KERN_CONT wasn't meaningful. The
ambiguity between "is this a continuation line" or "is this a plain
printk with no log level information" was reintroduced, and in fact
became an even bigger pain point because there was now the whole
record-level merging of kernel messages going on.
This patch reinstates the KERN_CONT as a real non-empty string marker,
so that the ambiguity is fixed once again.
But it's not a plain revert of that original removal: in the four years
since we made KERN_CONT an empty string again, not only has the format
of the log level markers changed, we've also had some usage changes in
this area.
For example, some ACPI code seems to use KERN_CONT _together_ with a log
level, and now uses both the KERN_CONT marker and (for example) a
KERN_INFO marker to show that it's an informational continuation of a
line.
Which is actually not a bad idea - if the continuation line cannot be
attached to its predecessor, without the log level information we don't
know what log level to assign to it (and we traditionally just assigned
it the default loglevel). So having both a log level and the KERN_CONT
marker is not necessarily a bad idea, but it does mean that we need to
actually iterate over potentially multiple markers, rather than just a
single one.
Also, since KERN_CONT was still conceptually needed, and encouraged, but
didn't actually _do_ anything, we've also had the reverse problem:
rather than having too many annotations it has too few, and there is bit
rot with code that no longer marks the continuation lines with the
KERN_CONT marker.
So this patch not only re-instates the non-empty KERN_CONT marker, it
also fixes up the cases of bit-rot I noticed in my own logs.
There are probably other cases where KERN_CONT will be needed to be
added, either because it is new code that never dealt with the need for
KERN_CONT, or old code that has bitrotted without anybody noticing.
That said, we should strive to avoid the need for KERN_CONT. It does
result in real problems for logging, and should generally not be seen as
a good feature. If we some day can get rid of the feature entirely,
because nobody does any fragmented printk calls, that would be lovely.
But until that point, let's at mark the code that relies on the hacky
multi-fragment kernel printk's. Not only does it avoid the ambiguity,
it also annotates code as "maybe this would be good to fix some day".
(That said, particularly during single-threaded bootup, the downsides of
KERN_CONT are very limited. Things get much hairier when you have
multiple threads going on and user level reading and writing logs too).
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
