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linux/fs/ext4
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Chandan Rajendra 9d5afec6b8 ext4: fix crash when a directory's i_size is too small 
On a ppc64 machine, when mounting a fuzzed ext2 image (generated by
fsfuzzer) the following call trace is seen,

VFS: brelse: Trying to free free buffer
WARNING: CPU: 1 PID: 6913 at /root/repos/linux/fs/buffer.c:1165 .__brelse.part.6+0x24/0x40
.__brelse.part.6+0x20/0x40 (unreliable)
.ext4_find_entry+0x384/0x4f0
.ext4_lookup+0x84/0x250
.lookup_slow+0xdc/0x230
.walk_component+0x268/0x400
.path_lookupat+0xec/0x2d0
.filename_lookup+0x9c/0x1d0
.vfs_statx+0x98/0x140
.SyS_newfstatat+0x48/0x80
system_call+0x58/0x6c

This happens because the directory that ext4_find_entry() looks up has
inode->i_size that is less than the block size of the filesystem. This
causes 'nblocks' to have a value of zero. ext4_bread_batch() ends up not
reading any of the directory file's blocks. This renders the entries in
bh_use[] array to continue to have garbage data. buffer_uptodate() on
bh_use[0] can then return a zero value upon which brelse() function is
invoked.

This commit fixes the bug by returning -ENOENT when the directory file
has no associated blocks.

Reported-by: Abdul Haleem <abdhalee@linux.vnet.ibm.com>
Signed-off-by: Chandan Rajendra <chandan@linux.vnet.ibm.com>
Cc: stable@vger.kernel.org
2017-12-11 15:00:57 -05:00
..
acl.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
acl.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
balloc.c Add support for online resizing of file systems with bigalloc. Fix a 2017-11-14 12:59:42 -08:00
bitmap.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
block_validity.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
dir.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
ext4_extents.h
ext4_jbd2.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
ext4_jbd2.h ext4, project: expand inode extra size if possible 2017-08-06 01:00:49 -04:00
ext4.h Add support for online resizing of file systems with bigalloc. Fix a 2017-11-14 12:59:42 -08:00
extents_status.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
extents_status.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
extents.c ext4: fix fdatasync(2) after fallocate(2) operation 2017-12-03 22:52:51 -05:00
file.c libnvdimm for 4.15 2017-11-17 09:51:57 -08:00
fsmap.c ext4: fix off-by-one fsmap error on 1k block filesystems 2017-06-23 00:58:57 -04:00
fsmap.h ext4: support GETFSMAP ioctls 2017-04-30 00:36:53 -04:00
fsync.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
hash.c ext4: remove useless test and assignment in strtohash functions 2017-08-24 15:11:34 -04:00
ialloc.c ext4: add missing error check in __ext4_new_inode() 2017-12-10 23:44:11 -05:00
indirect.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
inline.c ext4: prevent data corruption with inline data + DAX 2017-10-12 11:52:34 -04:00
inode.c ext4: support fast symlinks from ext3 file systems 2017-12-03 20:38:01 -05:00
ioctl.c Merge branch 'misc.compat' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2017-11-17 11:54:55 -08:00
Kconfig ext4: Switch to iomap for SEEK_HOLE / SEEK_DATA 2017-10-01 17:58:54 -04:00
Makefile License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
mballoc.c ext4: add support for online resizing with bigalloc 2017-10-29 09:38:46 -04:00
mballoc.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
migrate.c ext4: do not set posix acls on xattr inodes 2017-06-21 21:21:39 -04:00
mmp.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
move_extent.c ext4: add ext4_is_quota_file() 2017-06-22 11:31:25 -04:00
namei.c ext4: fix crash when a directory's i_size is too small 2017-12-11 15:00:57 -05:00
page-io.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
readpage.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
resize.c Add support for online resizing of file systems with bigalloc. Fix a 2017-11-14 12:59:42 -08:00
super.c Rename superblock flags (MS_xyz -> SB_xyz) 2017-11-27 13:05:09 -08:00
symlink.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
sysfs.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
truncate.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
xattr_security.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
xattr_trusted.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
xattr_user.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
xattr.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
xattr.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00