The log of UAF problem is listed below.
BUG: KASAN: use-after-free in jffs2_rmdir+0xa4/0x1cc [jffs2] at addr c1f165fc
Read of size 4 by task rm/8283
=============================================================================
BUG kmalloc-32 (Tainted: P B O ): kasan: bad access detected
-----------------------------------------------------------------------------
INFO: Allocated in 0xbbbbbbbb age=3054364 cpu=0 pid=0
0xb0bba6ef
jffs2_write_dirent+0x11c/0x9c8 [jffs2]
__slab_alloc.isra.21.constprop.25+0x2c/0x44
__kmalloc+0x1dc/0x370
jffs2_write_dirent+0x11c/0x9c8 [jffs2]
jffs2_do_unlink+0x328/0x5fc [jffs2]
jffs2_rmdir+0x110/0x1cc [jffs2]
vfs_rmdir+0x180/0x268
do_rmdir+0x2cc/0x300
ret_from_syscall+0x0/0x3c
INFO: Freed in 0x205b age=3054364 cpu=0 pid=0
0x2e9173
jffs2_add_fd_to_list+0x138/0x1dc [jffs2]
jffs2_add_fd_to_list+0x138/0x1dc [jffs2]
jffs2_garbage_collect_dirent.isra.3+0x21c/0x288 [jffs2]
jffs2_garbage_collect_live+0x16bc/0x1800 [jffs2]
jffs2_garbage_collect_pass+0x678/0x11d4 [jffs2]
jffs2_garbage_collect_thread+0x1e8/0x3b0 [jffs2]
kthread+0x1a8/0x1b0
ret_from_kernel_thread+0x5c/0x64
Call Trace:
[c17ddd20] [c02452d4] kasan_report.part.0+0x298/0x72c (unreliable)
[c17ddda0] [d2509680] jffs2_rmdir+0xa4/0x1cc [jffs2]
[c17dddd0] [c026da04] vfs_rmdir+0x180/0x268
[c17dde00] [c026f4e4] do_rmdir+0x2cc/0x300
[c17ddf40] [c001a658] ret_from_syscall+0x0/0x3c
The root cause is that we don't get "jffs2_inode_info.sem" before
we scan list "jffs2_inode_info.dents" in function jffs2_rmdir.
This patch add codes to get "jffs2_inode_info.sem" before we scan
"jffs2_inode_info.dents" to slove the UAF problem.
Signed-off-by: Zhe Li <lizhe67@huawei.com>
Reviewed-by: Hou Tao <houtao1@huawei.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Thanks for the advice mentioned in the email.
This is my v3 patch for this problem.
Mounting jffs2 on nand flash will get message "failed: I/O error"
with the steps listed below.
1.umount jffs2
2.erase nand flash
3.mount jffs2 on it (this mounting operation will be successful)
4.do chown or chmod to the mount point directory
5.umount jffs2
6.mount jffs2 on nand flash
After step 6, we will get message "mount ... failed: I/O error".
Typical image of this problem is like:
Empty space found from 0x00000000 to 0x008a0000
Inode node at xx, totlen 0x00000044, #ino 1, version 1, isize 0...
The reason for this mounting failure is that at the end of function
jffs2_scan_medium(), jffs2 will check the used_size and some info
of nr_blocks.If conditions are met, it will return -EIO.
The detail is that, in the steps listed above, step 4 will write
jffs2_raw_inode into flash without jffs2_raw_dirent, which will
cause that there are some jffs2_raw_inode but no jffs2_raw_dirent
on flash. This will meet the condition at the end of function
jffs2_scan_medium() and return -EIO if we umount jffs2 and mount it
again.
We notice that jffs2 add the value of c->unchecked_size if we find
an inode node while mounting. And jffs2 will never add the value of
c->unchecked_size in other situations. So this patch add one more
condition about c->unchecked_size of the judgement to fix this problem.
Signed-off-by: Zhe Li <lizhe67@huawei.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
There a wrong orphan node deleting in error handling path in
ubifs_jnl_update() and ubifs_jnl_rename(), which may cause
following error msg:
UBIFS error (ubi0:0 pid 1522): ubifs_delete_orphan [ubifs]:
missing orphan ino 65
Fix this by checking whether the node has been operated for
adding to orphan list before being deleted,
Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
Fixes: 823838a486 ("ubifs: Add hashes to the tree node cache")
Signed-off-by: Richard Weinberger <richard@nod.at>
Drop the repeated word "as" in a comment.
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Richard Weinberger <richard@nod.at>
Cc: linux-mtd@lists.infradead.org
Signed-off-by: Richard Weinberger <richard@nod.at>
Instead of creating ubifs file systems with UBIFS_FORMAT_VERSION
by default, add a module parameter ubifs.default_version to allow
the user to specify the desired version. Valid values are 4 to
UBIFS_FORMAT_VERSION (currently 5).
This way, one can for example create a file system with version 4
on kernel 4.19 which can still be mounted rw when downgrading to
kernel 4.9.
Signed-off-by: Martin Kaistra <martin.kaistra@linutronix.de>
Signed-off-by: Richard Weinberger <richard@nod.at>
nfs_wb_all() calls filemap_write_and_wait(), which uses
filemap_check_errors() to determine the error to return.
filemap_check_errors() only looks at the mapping->flags and will
therefore only return either -ENOSPC or -EIO. To ensure that the
correct error is returned on close(), nfs{,4}_file_flush() should call
filemap_check_wb_err() which looks at the errseq value in
mapping->wb_err without consuming it.
Fixes: 6fbda89b25 ("NFS: Replace custom error reporting mechanism with
generic one")
Signed-off-by: Scott Mayhew <smayhew@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
As recently done with with send/recv, flip the if after
rw_verify_aread() in io_{read,write}() and tabulise left bits left.
This removes mispredicted by a compiler jump on the success/fast path.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
As soon as we install the file descriptor, we have to assume that it
can get arbitrarily closed. We currently account memory (and note that
we did) after installing the ring fd, which means that it could be a
potential use-after-free condition if the fd is closed right after
being installed, but before we fiddle with the ctx.
In fact, syzbot reported this exact scenario:
BUG: KASAN: use-after-free in io_account_mem fs/io_uring.c:7397 [inline]
BUG: KASAN: use-after-free in io_uring_create fs/io_uring.c:8369 [inline]
BUG: KASAN: use-after-free in io_uring_setup+0x2797/0x2910 fs/io_uring.c:8400
Read of size 1 at addr ffff888087a41044 by task syz-executor.5/18145
CPU: 0 PID: 18145 Comm: syz-executor.5 Not tainted 5.8.0-rc7-next-20200729-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x18f/0x20d lib/dump_stack.c:118
print_address_description.constprop.0.cold+0xae/0x497 mm/kasan/report.c:383
__kasan_report mm/kasan/report.c:513 [inline]
kasan_report.cold+0x1f/0x37 mm/kasan/report.c:530
io_account_mem fs/io_uring.c:7397 [inline]
io_uring_create fs/io_uring.c:8369 [inline]
io_uring_setup+0x2797/0x2910 fs/io_uring.c:8400
do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45c429
Code: 8d b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 5b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f8f121d0c78 EFLAGS: 00000246 ORIG_RAX: 00000000000001a9
RAX: ffffffffffffffda RBX: 0000000000008540 RCX: 000000000045c429
RDX: 0000000000000000 RSI: 0000000020000040 RDI: 0000000000000196
RBP: 000000000078bf38 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000078bf0c
R13: 00007fff86698cff R14: 00007f8f121d19c0 R15: 000000000078bf0c
Move the accounting of the ring used locked memory before we get and
install the ring file descriptor.
Cc: stable@vger.kernel.org
Reported-by: syzbot+9d46305e76057f30c74e@syzkaller.appspotmail.com
Fixes: 309758254e ("io_uring: report pinned memory usage")
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Add a simple helper to set timestamps with a kernel space file name and
switch the early init code over to it.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Add a simple helper to mknod with a kernel space file name and switch
the early init code over to it. Remove the now unused ksys_mknod.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Add a simple helper to mkdir with a kernel space file name and switch
the early init code over to it. Remove the now unused ksys_mkdir.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Add a simple helper to symlink with a kernel space file name and switch
the early init code over to it. Remove the now unused ksys_symlink.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Add a simple helper to link with a kernel space file name and switch
the early init code over to it. Remove the now unused ksys_link.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Add a simple helper to check if a file exists based on kernel space file
name and switch the early init code over to it. Note that this
theoretically changes behavior as it always is based on the effective
permissions. But during early init that doesn't make a difference.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Add a simple helper to chroot with a kernel space file name and switch
the early init code over to it. Remove the now unused ksys_chroot.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Add a simple helper to chdir with a kernel space file name and switch
the early init code over to it. Remove the now unused ksys_chdir.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Add a simple helper to rmdir with a kernel space file name and switch
the early init code over to it. Remove the now unused ksys_rmdir.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Add a simple helper to unlink with a kernel space file name and switch
the early init code over to it. Remove the now unused ksys_unlink.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Like ksys_umount, but takes a kernel pointer for the destination path.
Switch over the umount in the init code, which just happen to work due to
the implicit set_fs(KERNEL_DS) during early init right now.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Like do_mount, but takes a kernel pointer for the destination path.
Switch over the mounts in the init code and devtmpfs to it, which
just happen to work due to the implicit set_fs(KERNEL_DS) during early
init right now.
Signed-off-by: Christoph Hellwig <hch@lst.de>
This mirrors do_unlinkat and will make life a little easier for
the init code to reuse the whole function with a kernel filename.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Factor out a path_umount helper that takes a struct path * instead of the
actual file name. This will allow to convert the init and devtmpfs code
to properly mount based on a kernel pointer instead of relying on the
implicit set_fs(KERNEL_DS) during early init.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Factor out a path_mount helper that takes a struct path * instead of the
actual file name. This will allow to convert the init and devtmpfs code
to properly mount based on a kernel pointer instead of relying on the
implicit set_fs(KERNEL_DS) during early init.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Rename utimes_common to vfs_utimes and make it available outside of
utimes.c. This will be used by the initramfs unpacking code.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Consolidate the validation of the timespec from the two callers into
utimes_common. That means it is done a little later (e.g. after the
path lookup), but I can't find anything that requires a specific
order of processing the errors.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Split out one helper each for path vs fd based operations.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Remove kmem_cache_alloc return value cast.
Coccinelle emits the following warning:
./fs/9p/vfs_inode.c:226:12-29: WARNING: casting value returned by memory allocation function to (struct v9fs_inode *) is useless.
Link: http://lkml.kernel.org/r/1596013140-49744-1-git-send-email-liheng40@huawei.com
Signed-off-by: Li Heng <liheng40@huawei.com>
[Dominique: commit message wording]
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
The argument passed to xas_set_err() to indicate an error should be negative.
Otherwise, xas_error() will return 0, and grab_mapping_entry() will return the
found entry instead of 'SIGBUS' when the entry is not in fact valid.
This would result in problems in subsequent code paths.
Link: https://lore.kernel.org/r/20200729034436.24267-1-lihao2018.fnst@cn.fujitsu.com
Reviewed-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Signed-off-by: Hao Li <lihao2018.fnst@cn.fujitsu.com>
Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
In fscrypt_set_bio_crypt_ctx(), ->i_crypt_info isn't known to be
non-NULL until we check fscrypt_inode_uses_inline_crypto(). So, load
->i_crypt_info after the check rather than before. This makes no
difference currently, but it prevents people from introducing bugs where
the pointer is dereferenced when it may be NULL.
Suggested-by: Dave Chinner <david@fromorbit.com>
Cc: Satya Tangirala <satyat@google.com>
Link: https://lore.kernel.org/r/20200727174158.121456-1-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
Caches should be small enough to discard them inline, so do that
instead of using a work queue.
Signed-off-by: Frank van der Linden <fllinden@amazon.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
If ->cq_timeouts modifications are done under ->completion_lock, we
don't really nee any fetch-and-add and other complex atomics. Replace it
with non-atomic FAA, that saves an implicit full memory barrier.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Add a helper to mark ctx->{cq,sq}_check_overflow to get rid of
duplicates, and it's clearer to check cq_overflow_list directly anyway.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Always do io_commit_cqring() after completing a request, even if it was
accounted as overflowed on the CQ side. Failing to do that may lead to
not to pushing deferred requests when needed, and so stalling the whole
ring.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
All ->cq_overflow modifications should be under completion_lock,
otherwise it can report a wrong number to the userspace. Fix it in
io_uring_cancel_files().
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Call __io_complete_rw() in io_iopoll_queue() instead of hand coding it.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
As io_kiocb have enough space, move ->work out of a union. It's safer
this way and removes ->work memcpy bouncing.
By the way make tabulation in struct io_kiocb consistent.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
There is no good reason to mess with file descriptors from in-kernel
code, switch the initrd loading to struct file based read and writes
instead.
Also Pass an explicit offset instead of ->f_pos, and to make that easier,
use file scope file structs and offsets everywhere except for
identify_ramdisk_image instead of the current strange mix.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
