linux/fs
Vegard Nossum 3632dee2f8 inotify: clean up inotify_read and fix locking problems
If userspace supplies an invalid pointer to a read() of an inotify
instance, the inotify device's event list mutex is unlocked twice.
This causes an unbalance which effectively leaves the data structure
unprotected, and we can trigger oopses by accessing the inotify
instance from different tasks concurrently.

The best fix (contributed largely by Linus) is a total rewrite
of the function in question:

On Thu, Jan 22, 2009 at 7:05 AM, Linus Torvalds wrote:
> The thing to notice is that:
>
>  - locking is done in just one place, and there is no question about it
>   not having an unlock.
>
>  - that whole double-while(1)-loop thing is gone.
>
>  - use multiple functions to make nesting and error handling sane
>
>  - do error testing after doing the things you always need to do, ie do
>   this:
>
>        mutex_lock(..)
>        ret = function_call();
>        mutex_unlock(..)
>
>        .. test ret here ..
>
>   instead of doing conditional exits with unlocking or freeing.
>
> So if the code is written in this way, it may still be buggy, but at least
> it's not buggy because of subtle "forgot to unlock" or "forgot to free"
> issues.
>
> This _always_ unlocks if it locked, and it always frees if it got a
> non-error kevent.

Cc: John McCutchan <ttb@tentacle.dhs.org>
Cc: Robert Love <rlove@google.com>
Cc: <stable@kernel.org>
Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-26 10:08:05 -08:00
..
9p Merge branch 'next' into for-linus 2008-12-25 11:40:09 +11:00
adfs vfs: Use const for kernel parser table 2008-10-13 10:10:37 -07:00
affs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6 2009-01-05 18:32:06 -08:00
afs fs: symlink write_begin allocation context fix 2009-01-04 13:33:20 -08:00
autofs zero i_uid/i_gid on inode allocation 2009-01-05 11:54:28 -05:00
autofs4 autofs4: fix string validation check order 2009-01-06 15:59:23 -08:00
befs befs: ensure fast symlinks are NUL-terminated 2008-12-31 18:07:40 -05:00
bfs bfs: check that filesystem fits on the blockdevice 2009-01-06 15:59:31 -08:00
btrfs Merge git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable 2009-01-16 09:32:33 -08:00
cifs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6 2009-01-05 18:32:06 -08:00
coda coda: fix fs/coda/sysctl.c build warnings when !CONFIG_SYSCTL 2009-01-08 08:31:01 -08:00
configfs zero i_uid/i_gid on inode allocation 2009-01-05 11:54:28 -05:00
cramfs zero i_uid/i_gid on inode allocation 2009-01-05 11:54:28 -05:00
debugfs debugfs: add helpers for exporting a size_t simple value 2009-01-07 10:00:16 -08:00
devpts zero i_uid/i_gid on inode allocation 2009-01-05 11:54:28 -05:00
dlm dlm: change rsbtbl rwlock to spinlock 2009-01-08 15:12:39 -06:00
ecryptfs fs/ecryptfs/inode.c: cleanup kerneldoc 2009-01-06 15:59:22 -08:00
efs [PATCH] switch all filesystems over to d_obtain_alias 2008-10-23 05:13:01 -04:00
exportfs Merge branch 'next' into for-linus 2008-12-25 11:40:09 +11:00
ext2 ext2: also update the inode on disk when dir is IS_DIRSYNC 2009-01-15 16:39:42 -08:00
ext3 filesystem freeze: add error handling of write_super_lockfs/unlockfs 2009-01-09 16:54:42 -08:00
ext4 filesystem freeze: add error handling of write_super_lockfs/unlockfs 2009-01-09 16:54:42 -08:00
fat Merge git://git.kernel.org/pub/scm/linux/kernel/git/hirofumi/fatfs-2.6 2008-12-30 20:33:34 -08:00
freevxfs freevxfs: ensure fast symlinks are NUL-terminated 2008-12-31 18:07:40 -05:00
fuse fuse: fix poll notify 2009-01-26 15:00:59 +01:00
gfs2 filesystem freeze: add error handling of write_super_lockfs/unlockfs 2009-01-09 16:54:42 -08:00
hfs CRED: Wrap task credential accesses in the HFS filesystem 2008-11-14 10:38:54 +11:00
hfsplus CRED: Wrap task credential accesses in the HFSplus filesystem 2008-11-14 10:38:54 +11:00
hostfs fs: symlink write_begin allocation context fix 2009-01-04 13:33:20 -08:00
hpfs CRED: Wrap task credential accesses in the HPFS filesystem 2008-11-14 10:38:55 +11:00
hppfs CRED: Use creds in file structs 2008-11-14 10:39:25 +11:00
hugetlbfs hugetlb: unsigned ret cannot be negative 2009-01-06 15:59:08 -08:00
isofs isofs check for NULL ->i_op in root directory is dead code 2009-01-05 11:53:38 -05:00
jbd jbd: remove excess kernel-doc notation 2009-01-08 08:31:01 -08:00
jbd2 Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4 2009-01-08 17:14:59 -08:00
jffs2 [JFFS2] remove junk prototypes 2009-01-09 21:05:21 +00:00
jfs filesystem freeze: add error handling of write_super_lockfs/unlockfs 2009-01-09 16:54:42 -08:00
lockd NLM: Clean up flow of control in make_socks() function 2009-01-07 15:40:44 -05:00
minix minix: fix add link's wrong position calculation 2009-01-06 15:59:27 -08:00
ncpfs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2009-01-07 11:31:52 -08:00
nfs fs: symlink write_begin allocation context fix 2009-01-04 13:33:20 -08:00
nfs_common SUNRPC: nfsacl_encode/nfsacl_decode should be exported as GPL-only 2008-12-23 15:21:32 -05:00
nfsd nfsd: last_byte_offset 2009-01-07 17:38:31 -05:00
nls remove CONFIG_KMOD from fs 2008-10-17 02:38:36 +11:00
notify inotify: clean up inotify_read and fix locking problems 2009-01-26 10:08:05 -08:00
ntfs ntfs: don't NULL i_op 2009-01-05 11:54:27 -05:00
ocfs2 fix similar typos to successfull 2009-01-08 08:31:15 -08:00
omfs zero i_uid/i_gid on inode allocation 2009-01-05 11:54:28 -05:00
openpromfs zero i_uid/i_gid on inode allocation 2009-01-05 11:54:28 -05:00
partitions block: fix bug in ptbl lookup cache 2009-01-09 21:46:13 +01:00
proc Merge git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-2.6-nommu 2009-01-09 14:00:58 -08:00
qnx4
ramfs NOMMU: Fix cleanup handling in ramfs_nommu_get_umapped_area() 2009-01-08 12:04:46 +00:00
reiserfs filesystem freeze: add error handling of write_super_lockfs/unlockfs 2009-01-09 16:54:42 -08:00
romfs romfs: romfs_iget() - unsigned ino >= 0 is always true 2009-01-08 08:31:14 -08:00
smbfs fs: symlink write_begin allocation context fix 2009-01-04 13:33:20 -08:00
squashfs btrfs & squashfs: Move btrfs and squashfsto's magic number to <linux/magic.h> 2009-01-15 16:39:38 -08:00
sysfs zero i_uid/i_gid on inode allocation 2009-01-05 11:54:28 -05:00
sysv sysv: ensure fast symlinks are NUL-terminated 2008-12-31 18:07:39 -05:00
ubifs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2009-01-07 11:31:52 -08:00
udf Merge branch 'master' into next 2008-12-04 17:16:36 +11:00
ufs CRED: Wrap task credential accesses in the UFS filesystem 2008-11-14 10:39:04 +11:00
xfs Long btree pointers are still 64 bit on disk 2009-01-22 01:23:11 -06:00
aio.c [CVE-2009-0029] System call wrappers part 16 2009-01-14 14:15:25 +01:00
anon_inodes.c anon_inodes: use fops->owner for module refcount 2008-12-31 16:55:44 +02:00
attr.c CRED: Wrap task credential accesses in the filesystem subsystem 2008-11-14 10:39:05 +11:00
bad_inode.c kill ->dir_notify() 2008-12-31 18:07:43 -05:00
binfmt_aout.c sanitize ifdefs in binfmt_aout 2009-01-03 11:45:54 -08:00
binfmt_elf_fdpic.c FDPIC: Don't attempt to expand the userspace stack to fill the space allocated 2009-01-08 12:04:47 +00:00
binfmt_elf.c ELF: implement AT_RANDOM for glibc PRNG seeding 2009-01-08 08:31:12 -08:00
binfmt_em86.c Allow recursion in binfmt_script and binfmt_misc 2008-10-16 11:21:38 -07:00
binfmt_flat.c FLAT: Don't attempt to expand the userspace stack to fill the space allocated 2009-01-08 12:04:47 +00:00
binfmt_misc.c fs/binfmt_misc.c: add terminating newline to /proc/sys/fs/binfmt_misc/status 2009-01-06 15:59:19 -08:00
binfmt_script.c Allow recursion in binfmt_script and binfmt_misc 2008-10-16 11:21:38 -07:00
binfmt_som.c CRED: Make execve() take advantage of copy-on-write credentials 2008-11-14 10:39:24 +11:00
bio-integrity.c bio: allow individual slabs in the bio_set 2008-12-29 08:29:23 +01:00
bio.c [SCSI] block: make blk_rq_map_user take a NULL user-space buffer for WRITE 2009-01-02 11:10:35 -06:00
block_dev.c filesystem freeze: implement generic freeze feature 2009-01-09 16:54:42 -08:00
buffer.c [CVE-2009-0029] System call wrappers part 10 2009-01-14 14:15:22 +01:00
char_dev.c fs: fix name overwrite in __register_chrdev_region() 2009-01-06 15:59:13 -08:00
compat_binfmt_elf.c
compat_ioctl.c
compat.c [CVE-2009-0029] Make sys_pselect7 static 2009-01-14 14:15:16 +01:00
dcache.c [CVE-2009-0029] System call wrappers part 20 2009-01-14 14:15:26 +01:00
dcookies.c [CVE-2009-0029] System call wrapper special cases 2009-01-14 14:15:18 +01:00
direct-io.c fs: truncate blocks outside i_size after O_DIRECT write error 2009-01-06 15:59:06 -08:00
dquot.c quota: don't set grace time when user isn't above softlimit 2009-01-08 08:31:01 -08:00
drop_caches.c
eventfd.c [CVE-2009-0029] System call wrappers part 32 2009-01-14 14:15:31 +01:00
eventpoll.c [CVE-2009-0029] System call wrappers part 23 2009-01-14 14:15:28 +01:00
exec.c [CVE-2009-0029] System call wrappers part 27 2009-01-14 14:15:29 +01:00
fcntl.c [CVE-2009-0029] System call wrappers part 15 2009-01-14 14:15:24 +01:00
fifo.c [PATCH] introduce fmode_t, do annotations 2008-10-21 07:47:06 -04:00
file_table.c filp_cachep can be static in fs/file_table.c 2008-12-31 18:07:42 -05:00
file.c
filesystems.c [CVE-2009-0029] System call wrappers part 27 2009-01-14 14:15:29 +01:00
fs-writeback.c fs: sys_sync fix 2009-01-06 15:59:09 -08:00
generic_acl.c
inode.c partial revert of asynchronous inode delete 2009-01-09 13:15:49 -08:00
internal.h CRED: Make execve() take advantage of copy-on-write credentials 2008-11-14 10:39:24 +11:00
ioctl.c [CVE-2009-0029] System call wrappers part 15 2009-01-14 14:15:24 +01:00
ioprio.c [CVE-2009-0029] System call wrappers part 28 2009-01-14 14:15:30 +01:00
Kconfig Merge git://git.kernel.org/pub/scm/linux/kernel/git/pkl/squashfs-linus 2009-01-09 15:18:49 -08:00
Kconfig.binfmt CORE_DUMP_DEFAULT_ELF_HEADERS depends on ELF_CORE 2009-01-09 16:54:41 -08:00
libfs.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6 2009-01-05 18:32:06 -08:00
locks.c [CVE-2009-0029] System call wrappers part 16 2009-01-14 14:15:25 +01:00
Makefile Merge git://git.kernel.org/pub/scm/linux/kernel/git/pkl/squashfs-linus 2009-01-09 15:18:49 -08:00
mbcache.c
mpage.c do_mpage_readpage(): remove useless clear_buffer_mapped() call 2009-01-06 15:59:01 -08:00
namei.c [CVE-2009-0029] System call wrappers part 29 2009-01-14 14:15:30 +01:00
namespace.c [CVE-2009-0029] System call wrappers part 14 2009-01-14 14:15:24 +01:00
nfsctl.c [CVE-2009-0029] System call wrappers part 27 2009-01-14 14:15:29 +01:00
no-block.c
open.c [CVE-2009-0029] System call wrappers part 30 2009-01-14 14:15:30 +01:00
pipe.c [CVE-2009-0029] System call wrappers part 33 2009-01-14 14:15:32 +01:00
pnode.c
pnode.h
posix_acl.c CRED: Wrap task credential accesses in the filesystem subsystem 2008-11-14 10:39:05 +11:00
quota_tree.c quota: Split off quota tree handling into a separate file 2009-01-05 08:40:21 -08:00
quota_tree.h quota: Split off quota tree handling into a separate file 2009-01-05 08:40:21 -08:00
quota_v1.c quota: Move quotaio_v[12].h from include/linux/ to fs/ 2009-01-05 08:36:58 -08:00
quota_v2.c quota: Convert union in mem_dqinfo to a pointer 2009-01-05 08:40:21 -08:00
quota.c [CVE-2009-0029] System call wrappers part 20 2009-01-14 14:15:26 +01:00
quotaio_v1.h quota: Move quotaio_v[12].h from include/linux/ to fs/ 2009-01-05 08:36:58 -08:00
quotaio_v2.h quota: Split off quota tree handling into a separate file 2009-01-05 08:40:21 -08:00
read_write.c [CVE-2009-0029] System call wrappers part 20 2009-01-14 14:15:26 +01:00
read_write.h
readdir.c [CVE-2009-0029] System call wrappers part 32 2009-01-14 14:15:31 +01:00
select.c [CVE-2009-0029] System call wrappers part 32 2009-01-14 14:15:31 +01:00
seq_file.c Merge branch 'cpus4096-for-linus-3' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-01-03 12:04:39 -08:00
signalfd.c [CVE-2009-0029] System call wrappers part 31 2009-01-14 14:15:31 +01:00
splice.c [CVE-2009-0029] System call wrappers part 31 2009-01-14 14:15:31 +01:00
stack.c
stat.c [CVE-2009-0029] System call wrappers part 30 2009-01-14 14:15:30 +01:00
super.c [CVE-2009-0029] System call wrappers part 11 2009-01-14 14:15:23 +01:00
sync.c [CVE-2009-0029] System call wrappers part 09 2009-01-14 14:15:21 +01:00
timerfd.c [CVE-2009-0029] System call wrappers part 32 2009-01-14 14:15:31 +01:00
utimes.c [CVE-2009-0029] System call wrappers part 30 2009-01-14 14:15:30 +01:00
xattr_acl.c
xattr.c [CVE-2009-0029] System call wrappers part 13 2009-01-14 14:15:23 +01:00