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
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acl.c
acl.h
balloc.c
bitmap.c
block_validity.c
dir.c
ext4_extents.h
ext4_jbd2.c
ext4_jbd2.h
ext4.h
extents_status.c
extents_status.h
extents.c
file.c
fsmap.c
fsmap.h
fsync.c
hash.c
ialloc.c
indirect.c
inline.c
inode.c
ioctl.c
Kconfig
Makefile
mballoc.c
mballoc.h
migrate.c
mmp.c
move_extent.c
namei.c
page-io.c
readpage.c
resize.c
super.c
symlink.c
sysfs.c
truncate.h
xattr_security.c
xattr_trusted.c
xattr_user.c
xattr.c
xattr.h