diff options
| author | Eryu Guan <guaneryu@gmail.com> | 2016-03-12 21:40:32 -0500 |
|---|---|---|
| committer | Sasha Levin <sasha.levin@oracle.com> | 2016-07-10 23:07:14 -0400 |
| commit | 7925f4fb3d8b5b0c1bb9c5ded85078197c6f87af (patch) | |
| tree | b8e0be4e75f8a1752320aef4b71c3f86d642abe8 /fs | |
| parent | 6e939f787e830777bdafd5d70f13ed6498dc7ac0 (diff) | |
ext4: fix NULL pointer dereference in ext4_mark_inode_dirty()
[ Upstream commit 5e1021f2b6dff1a86a468a1424d59faae2bc63c1 ]
ext4_reserve_inode_write() in ext4_mark_inode_dirty() could fail on
error (e.g. EIO) and iloc.bh can be NULL in this case. But the error is
ignored in the following "if" condition and ext4_expand_extra_isize()
might be called with NULL iloc.bh set, which triggers NULL pointer
dereference.
This is uncovered by commit 8b4953e13f4c ("ext4: reserve code points for
the project quota feature"), which enlarges the ext4_inode size, and
run the following script on new kernel but with old mke2fs:
#/bin/bash
mnt=/mnt/ext4
devname=ext4-error
dev=/dev/mapper/$devname
fsimg=/home/fs.img
trap cleanup 0 1 2 3 9 15
cleanup()
{
umount $mnt >/dev/null 2>&1
dmsetup remove $devname
losetup -d $backend_dev
rm -f $fsimg
exit 0
}
rm -f $fsimg
fallocate -l 1g $fsimg
backend_dev=`losetup -f --show $fsimg`
devsize=`blockdev --getsz $backend_dev`
good_tab="0 $devsize linear $backend_dev 0"
error_tab="0 $devsize error $backend_dev 0"
dmsetup create $devname --table "$good_tab"
mkfs -t ext4 $dev
mount -t ext4 -o errors=continue,strictatime $dev $mnt
dmsetup load $devname --table "$error_tab" && dmsetup resume $devname
echo 3 > /proc/sys/vm/drop_caches
ls -l $mnt
exit 0
[ Patch changed to simplify the function a tiny bit. -- Ted ]
Signed-off-by: Eryu Guan <guaneryu@gmail.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/ext4/inode.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index f43996884242..ba12e2953aec 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -5094,6 +5094,8 @@ int ext4_mark_inode_dirty(handle_t *handle, struct inode *inode) might_sleep(); trace_ext4_mark_inode_dirty(inode, _RET_IP_); err = ext4_reserve_inode_write(handle, inode, &iloc); + if (err) + return err; if (ext4_handle_valid(handle) && EXT4_I(inode)->i_extra_isize < sbi->s_want_extra_isize && !ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND)) { @@ -5124,9 +5126,7 @@ int ext4_mark_inode_dirty(handle_t *handle, struct inode *inode) } } } - if (!err) - err = ext4_mark_iloc_dirty(handle, inode, &iloc); - return err; + return ext4_mark_iloc_dirty(handle, inode, &iloc); } /* |