A full expalantion of io_uring is beyond the scope of this commit
description, but in summary it is an asynchronous I/O mechanism
which allows for I/O requests and the resulting data to be queued
in memory mapped "rings" which are shared between the kernel and
userspace. Optionally, io_uring offers the ability for applications
to spawn kernel threads to dequeue I/O requests from the ring and
submit the requests in the kernel, helping to minimize the syscall
overhead. Rings are accessed in userspace by memory mapping a file
descriptor provided by the io_uring_setup(2), and can be shared
between applications as one might do with any open file descriptor.
Finally, process credentials can be registered with a given ring
and any process with access to that ring can submit I/O requests
using any of the registered credentials.
While the io_uring functionality is widely recognized as offering a
vastly improved, and high performing asynchronous I/O mechanism, its
ability to allow processes to submit I/O requests with credentials
other than its own presents a challenge to LSMs. When a process
creates a new io_uring ring the ring's credentials are inhertied
from the calling process; if this ring is shared with another
process operating with different credentials there is the potential
to bypass the LSMs security policy. Similarly, registering
credentials with a given ring allows any process with access to that
ring to submit I/O requests with those credentials.
In an effort to allow LSMs to apply security policy to io_uring I/O
operations, this patch adds two new LSM hooks. These hooks, in
conjunction with the LSM anonymous inode support previously
submitted, allow an LSM to apply access control policy to the
sharing of io_uring rings as well as any io_uring credential changes
requested by a process.
The new LSM hooks are described below:
* int security_uring_override_creds(cred)
Controls if the current task, executing an io_uring operation,
is allowed to override it's credentials with @cred. In cases
where the current task is a user application, the current
credentials will be those of the user application. In cases
where the current task is a kernel thread servicing io_uring
requests the current credentials will be those of the io_uring
ring (inherited from the process that created the ring).
* int security_uring_sqpoll(void)
Controls if the current task is allowed to create an io_uring
polling thread (IORING_SETUP_SQPOLL). Without a SQPOLL thread
in the kernel processes must submit I/O requests via
io_uring_enter(2) which allows us to compare any requested
credential changes against the application making the request.
With a SQPOLL thread, we can no longer compare requested
credential changes against the application making the request,
the comparison is made against the ring's credentials.
Signed-off-by: Paul Moore <paul@paul-moore.com>
Converting io_uring's anonymous inode to the secure anon inode API
enables LSMs to enforce policy on the io_uring anonymous inodes if
they chose to do so. This is an important first step towards
providing the necessary mechanisms so that LSMs can apply security
policy to io_uring operations.
Signed-off-by: Paul Moore <paul@paul-moore.com>
Extending the secure anonymous inode support to other subsystems
requires that we have a secure anon_inode_getfile() variant in
addition to the existing secure anon_inode_getfd() variant.
Thankfully we can reuse the existing __anon_inode_getfile() function
and just wrap it with the proper arguments.
Acked-by: Mickaël Salaün <mic@linux.microsoft.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
This patch adds basic auditing to io_uring operations, regardless of
their context. This is accomplished by allocating audit_context
structures for the io-wq worker and io_uring SQPOLL kernel threads
as well as explicitly auditing the io_uring operations in
io_issue_sqe(). Individual io_uring operations can bypass auditing
through the "audit_skip" field in the struct io_op_def definition for
the operation; although great care must be taken so that security
relevant io_uring operations do not bypass auditing; please contact
the audit mailing list (see the MAINTAINERS file) with any questions.
The io_uring operations are audited using a new AUDIT_URINGOP record,
an example is shown below:
type=UNKNOWN[1336] msg=audit(1631800225.981:37289):
uring_op=19 success=yes exit=0 items=0 ppid=15454 pid=15681
uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0
subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023
key=(null)
Thanks to Richard Guy Briggs for review and feedback.
Signed-off-by: Paul Moore <paul@paul-moore.com>
Because of .., files outside the share directory
could be accessed. To prevent this, normalize
the given path and remove all . and ..
components.
In addition to the usual large set of regression tests (smbtorture
and xfstests), ran various tests on this to specifically check
path name validation including libsmb2 tests to verify path
normalization:
./examples/smb2-ls-async smb://172.30.1.15/homes2/../
./examples/smb2-ls-async smb://172.30.1.15/homes2/foo/../
./examples/smb2-ls-async smb://172.30.1.15/homes2/foo/../../
./examples/smb2-ls-async smb://172.30.1.15/homes2/foo/../
./examples/smb2-ls-async smb://172.30.1.15/homes2/foo/..bar/
./examples/smb2-ls-async smb://172.30.1.15/homes2/foo/bar../
./examples/smb2-ls-async smb://172.30.1.15/homes2/foo/bar..
./examples/smb2-ls-async smb://172.30.1.15/homes2/foo/bar../../../../
Signed-off-by: Hyunchul Lee <hyc.lee@gmail.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Below traces are observed during fsstress and system got hung.
[ 130.698396] watchdog: BUG: soft lockup - CPU#6 stuck for 26s!
Cc: stable@vger.kernel.org # 5.13+
Signed-off-by: Rohith Surabattula <rohiths@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
During unlink/rename instead of closing all the deferred handles
under tcon, close only handles under the requested dentry.
Signed-off-by: Rohith Surabattula <rohiths@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
When we get an error flushing one device, during a super block commit, we
record the error in the device structure, in the field 'last_flush_error'.
This is used to later check if we should error out the super block commit,
depending on whether the number of flush errors is greater than or equals
to the maximum tolerated device failures for a raid profile.
However if we get a transient device flush error, unmount the filesystem
and later try to mount it, we can fail the mount because we treat that
past error as critical and consider the device is missing. Even if it's
very likely that the error will happen again, as it's probably due to a
hardware related problem, there may be cases where the error might not
happen again. One example is during testing, and a test case like the
new generic/648 from fstests always triggers this. The test cases
generic/019 and generic/475 also trigger this scenario, but very
sporadically.
When this happens we get an error like this:
$ mount /dev/sdc /mnt
mount: /mnt wrong fs type, bad option, bad superblock on /dev/sdc, missing codepage or helper program, or other error.
$ dmesg
(...)
[12918.886926] BTRFS warning (device sdc): chunk 13631488 missing 1 devices, max tolerance is 0 for writable mount
[12918.888293] BTRFS warning (device sdc): writable mount is not allowed due to too many missing devices
[12918.890853] BTRFS error (device sdc): open_ctree failed
The failure happens because when btrfs_check_rw_degradable() is called at
mount time, or at remount from RO to RW time, is sees a non zero value in
a device's ->last_flush_error attribute, and therefore considers that the
device is 'missing'.
Fix this by setting a device's ->last_flush_error to zero when we close a
device, making sure the error is not seen on the next mount attempt. We
only need to track flush errors during the current mount, so that we never
commit a super block if such errors happened.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
During a verity rollback, if we fail to update the inode or delete the
orphan, we abort the transaction and return without releasing our
transaction handle. Fix that by releasing the handle.
Fixes: 146054090b ("btrfs: initial fsverity support")
Fixes: 705242538f ("btrfs: verity metadata orphan items")
Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There is a BUG_ON() in btrfs_csum_one_bio() to catch code logic error.
It has indeed caught several bugs during subpage development.
But the BUG_ON() itself will bring down the whole system which is
an overkill.
Replace it with a WARN() and exit gracefully, so that it won't crash the
whole system while we can still catch the code logic error.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Pull io_uring iov_iter retry fixes from Jens Axboe:
"This adds a helper to save/restore iov_iter state, and modifies
io_uring to use it.
After that is done, we can now kill the iter->truncated addition that
we added for this release. The io_uring change is being overly
cautious with the save/restore/advance, but better safe than sorry and
we can always improve that and reduce the overhead if it proves to be
of concern. The only case to be worried about in this regard is huge
IO, where iteration can take a while to iterate segments.
I spent some time writing test cases, and expanded the coverage quite
a bit from the last posting of this. liburing carries this regression
test case now:
https://git.kernel.dk/cgit/liburing/tree/test/file-verify.c
which exercises all of this. It now also supports provided buffers,
and explicitly tests for end-of-file/device truncation as well.
On top of that, Pavel sanitized the IOPOLL retry path to follow the
exact same pattern as normal IO"
* tag 'iov_iter.3-5.15-2021-09-17' of git://git.kernel.dk/linux-block:
io_uring: move iopoll reissue into regular IO path
Revert "iov_iter: track truncated size"
io_uring: use iov_iter state save/restore helpers
iov_iter: add helper to save iov_iter state
Pull io_uring fixes from Jens Axboe:
"Mostly fixes for regressions in this cycle, but also a few fixes that
predate this release.
The odd one out is a tweak to the direct files added in this release,
where attempting to reuse a slot is allowed instead of needing an
explicit removal of that slot first. It's a considerable improvement
in usability to that API, hence I'm sending it for -rc2.
- io-wq race fix and cleanup (Hao)
- loop_rw_iter() type fix
- SQPOLL max worker race fix
- Allow poll arm for O_NONBLOCK files, fixing a case where it's
impossible to properly use io_uring if you cannot modify the file
flags
- Allow direct open to simply reuse a slot, instead of needing it
explicitly removed first (Pavel)
- Fix a case where we missed signal mask restoring in cqring_wait, if
we hit -EFAULT (Xiaoguang)"
* tag 'io_uring-5.15-2021-09-17' of git://git.kernel.dk/linux-block:
io_uring: allow retry for O_NONBLOCK if async is supported
io_uring: auto-removal for direct open/accept
io_uring: fix missing sigmask restore in io_cqring_wait()
io_uring: pin SQPOLL data before unlocking ring lock
io-wq: provide IO_WQ_* constants for IORING_REGISTER_IOWQ_MAX_WORKERS arg items
io-wq: fix potential race of acct->nr_workers
io-wq: code clean of io_wqe_create_worker()
io_uring: ensure symmetry in handling iter types in loop_rw_iter()
When the back channel enters SEQ4_STATUS_CB_PATH_DOWN state, the client
recovers by sending BIND_CONN_TO_SESSION but the server fails to recover
the back channel and leaves it as NFSD4_CB_DOWN.
Fix by enhancing nfsd4_bind_conn_to_session to probe the back channel
by calling nfsd4_probe_callback.
Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Dai Ngo reports that, since the XDR overhaul, the NLM server crashes
when the TEST procedure wants to return NLM_DENIED. There is a bug
in svcxdr_encode_owner() that none of our standard test cases found.
Replace the open-coded function with a call to an appropriate
pre-fabricated XDR helper.
Reported-by: Dai Ngo <Dai.Ngo@oracle.com>
Fixes: a6a63ca565 ("lockd: Common NLM XDR helpers")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
rwlock.h specifically asks to not be included directly.
In fact, the proper spinlock.h include isn't needed either,
it comes with the huge pile that kthread.h ends up pulling
in, so just drop it entirely.
Signed-off-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
The function __init_rwsem() is not part of the official API, it just a helper
function used by init_rwsem().
Changing the lock's class and name should be done by using
lockdep_set_class_and_name() after the has been fully initialized. The overhead
of the additional class struct and setting it twice is negligible and it works
across all locks.
Fully initialize the lock with init_rwsem() and then set the custom class and
name for the lock.
Fixes: 730633f0b7 ("mm: Protect operations adding pages to page cache with invalidate_lock")
Link: https://lore.kernel.org/r/20210901084403.g4fezi23cixemlhh@linutronix.de
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Jan Kara <jack@suse.cz>
As Yi Zhuang reported in bugzilla:
https://bugzilla.kernel.org/show_bug.cgi?id=214299
There is potential deadlock during quota data flush as below:
Thread A: Thread B:
f2fs_dquot_acquire
down_read(&sbi->quota_sem)
f2fs_write_checkpoint
block_operations
f2fs_look_all
down_write(&sbi->cp_rwsem)
f2fs_quota_write
f2fs_write_begin
__do_map_lock
f2fs_lock_op
down_read(&sbi->cp_rwsem)
__need_flush_qutoa
down_write(&sbi->quota_sem)
This patch changes block_operations() to use trylock, if it fails,
it means there is potential quota data updater, in this condition,
let's flush quota data first and then trylock again to check dirty
status of quota data.
The side effect is: in heavy race condition (e.g. multi quota data
upaters vs quota data flusher), it may decrease the probability of
synchronizing quota data successfully in checkpoint() due to limited
retry time of quota flush.
Reported-by: Yi Zhuang <zhuangyi1@huawei.com>
Signed-off-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
We can make code little more readable by using kernel macros clamp/max.
This were found with kernel included Coccinelle minmax script.
Signed-off-by: Kari Argillander <kari.argillander@gmail.com>
Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
We do not need this check as this is same thing as
NTFS_MIN_MFT_ZONE > zlen. We already check NTFS_MIN_MFT_ZONE <= zlen and
exit because is too big request. Remove it so code is cleaner.
Signed-off-by: Kari Argillander <kari.argillander@gmail.com>
Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
If ntfs_refresh_zone() returns error it will be changed to -ENOSPC. It
is not right. Also caller of this functions also check other errors.
Fixes: 78ab59fee0 ("fs/ntfs3: Rework file operations")
Signed-off-by: Kari Argillander <kari.argillander@gmail.com>
Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
Remove braces from single statment block as they are not needed. Also
Linux kernel coding style guide recommend this and checkpatch warn about
this.
Signed-off-by: Kari Argillander <kari.argillander@gmail.com>
Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
The qnx4 directory entries are 64-byte blocks that have different
contents depending on the a status byte that is in the last byte of the
block.
In particular, a directory entry can be either a "link info" entry with
a 48-byte name and pointers to the real inode information, or an "inode
entry" with a smaller 16-byte name and the full inode information.
But the code was written to always just treat the directory name as if
it was part of that "inode entry", and just extend the name to the
longer case if the status byte said it was a link entry.
That work just fine and gives the right results, but now that gcc is
tracking data structure accesses much more, the code can trigger a
compiler error about using up to 48 bytes (the long name) in a structure
that only has that shorter name in it:
fs/qnx4/dir.c: In function ‘qnx4_readdir’:
fs/qnx4/dir.c:51:32: error: ‘strnlen’ specified bound 48 exceeds source size 16 [-Werror=stringop-overread]
51 | size = strnlen(de->di_fname, size);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~
In file included from fs/qnx4/qnx4.h:3,
from fs/qnx4/dir.c:16:
include/uapi/linux/qnx4_fs.h:45:25: note: source object declared here
45 | char di_fname[QNX4_SHORT_NAME_MAX];
| ^~~~~~~~
which is because the source code doesn't really make this whole "one of
two different types" explicit.
Fix this by introducing a very explicit union of the two types, and
basically explaining to the compiler what is really going on.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Get rid of the need to do re-expand and revert on an iterator when we
encounter a short IO, or failure that warrants a retry. Use the new
state save/restore helpers instead.
We keep the iov_iter_state persistent across retries, if we need to
restart the read or write operation. If there's a pending retry, the
operation will always exit with the state correctly saved.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
A common complaint is that using O_NONBLOCK files with io_uring can be a
bit of a pain. Be a bit nicer and allow normal retry IFF the file does
support async behavior. This makes it possible to use io_uring more
reliably with O_NONBLOCK files, for use cases where it either isn't
possible or feasible to modify the file flags.
Cc: stable@vger.kernel.org
Reported-and-tested-by: Dan Melnic <dmm@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
It might be inconvenient that direct open/accept deviates from the
update semantics and fails if the slot is taken instead of removing a
file sitting there. Implement this auto-removal.
Note that removal might need to allocate and so may fail. However, if an
empty slot is specified, it's guaraneed to not fail on the fd
installation side for valid userspace programs. It's needed for users
who can't tolerate such failures, e.g. accept where the other end
never retries.
Suggested-by: Franz-B. Tuneke <franz-bernhard.tuneke@tu-dortmund.de>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/c896f14ea46b0eaa6c09d93149e665c2c37979b4.1631632300.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We need to re-check sqd->thread after we've dropped the lock. Pin
the sqd before doing the lockdep lock dance, and check if the thread
is alive after that. It's either NULL or alive, as the SQPOLL thread
cannot exit without holding the same sqd->lock.
Reported-and-tested-by: syzbot+337de45f13a4fd54d708@syzkaller.appspotmail.com
Fixes: fa84693b3c ("io_uring: ensure IORING_REGISTER_IOWQ_MAX_WORKERS works with SQPOLL")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Correct kernel-doc comments pointed out by the
automated kernel test robot.
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
checkpatch complains about source files with filenames (e.g. in
these cases just below the SPDX header in comments at the top of
various files in fs/cifs). It also is helpful to change this now
so will be less confusing when the parent directory is renamed
e.g. from fs/cifs to fs/smb_client (or fs/smbfs)
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
We do not have any reason to keep old linear search in. Before this was
used for error path or if table was so big that it cannot be allocated.
Current binary search implementation won't need error path. Remove old
references to linear entry search.
Signed-off-by: Kari Argillander <kari.argillander@gmail.com>
Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
We could try to optimize algorithm to first fill just small table and
after that use bigger table all the way up to ARRAY_SIZE(offs). This
way we can use bigger search array, but not lose benefits with entry
count smaller < ARRAY_SIZE(offs).
Signed-off-by: Kari Argillander <kari.argillander@gmail.com>
Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
Current binary search allocates memory for table and fill whole table
before we start actual binary search. This is quite inefficient because
table fill will always be O(n). Also if table is huge we need to
reallocate memory which is costly.
This implementation use just stack memory and always when table is full
we will check if last element is <= and if not start table fill again.
The idea was that it would be same cost as table reallocation.
Signed-off-by: Kari Argillander <kari.argillander@gmail.com>
Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
There is lot of headers which we do not need in this file. Delete them
and add what we really need. Here is list which identify why we need
this header.
<linux/kernel.h> // min()
<linux/slab.h> // kzalloc()
<linux/stddef.h> // offsetof()
<linux/string.h> // memcpy(), memset()
<linux/types.h> // u8, size_t, etc.
"debug.h" // PtrOffset()
Signed-off-by: Kari Argillander <kari.argillander@gmail.com>
Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
There is no headers. They will be included through ntfs_fs.c, but that
is not right thing to do. Let's include headers what this file need
straight away.
types.h is needed for __le16, u8 etc.
kernel.h is needed for le16_to_cpu()
Signed-off-by: Kari Argillander <kari.argillander@gmail.com>
Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
