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| author |   Jeffle Xu <jefflexu@linux.alibaba.com> | 2020-04-23 15:46:44 +0800 |
|---|---|---|
| committer |   Theodore Ts'o <tytso@mit.edu> | 2020-06-03 23:16:49 -0400 |
| commit | 8418897f1bf87da0cb6936489d57a4320c32c0af (patch) | |
| tree | 9be29f6ac592f2b84989fcbfc3724d258b605c90 /fs/ext4 | |
| parent | ext4: Avoid freeing inodes on dirty list (diff) | |
| download | wireguard-linux-8418897f1bf87da0cb6936489d57a4320c32c0af.tar.xz wireguard-linux-8418897f1bf87da0cb6936489d57a4320c32c0af.zip | |
ext4: fix error pointer dereference
Don't pass error pointers to brelse().
commit 7159a986b420 ("ext4: fix some error pointer dereferences") has fixed
some cases, fix the remaining one case.
Once ext4_xattr_block_find()->ext4_sb_bread() failed, error pointer is
stored in @bs->bh, which will be passed to brelse() in the cleanup
routine of ext4_xattr_set_handle(). This will then cause a NULL panic
crash in __brelse().
BUG: unable to handle kernel NULL pointer dereference at 000000000000005b
RIP: 0010:__brelse+0x1b/0x50
Call Trace:
ext4_xattr_set_handle+0x163/0x5d0
ext4_xattr_set+0x95/0x110
__vfs_setxattr+0x6b/0x80
__vfs_setxattr_noperm+0x68/0x1b0
vfs_setxattr+0xa0/0xb0
setxattr+0x12c/0x1a0
path_setxattr+0x8d/0xc0
__x64_sys_setxattr+0x27/0x30
do_syscall_64+0x60/0x250
entry_SYSCALL_64_after_hwframe+0x49/0xbe
In this case, @bs->bh stores '-EIO' actually.
Fixes: fb265c9cb49e ("ext4: add ext4_sb_bread() to disambiguate ENOMEM cases")
Signed-off-by: Jeffle Xu <jefflexu@linux.alibaba.com>
Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: stable@kernel.org # 2.6.19
Reviewed-by: Ritesh Harjani <riteshh@linux.ibm.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/1587628004-95123-1-git-send-email-jefflexu@linux.alibaba.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Diffstat (limited to 'fs/ext4')
| -rw-r--r-- | fs/ext4/xattr.c | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c index 21df43a25328..01ba66373e97 100644 --- a/fs/ext4/xattr.c +++ b/fs/ext4/xattr.c @@ -1800,8 +1800,11 @@ ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i, if (EXT4_I(inode)->i_file_acl) { /* The inode already has an extended attribute block. */ bs->bh = ext4_sb_bread(sb, EXT4_I(inode)->i_file_acl, REQ_PRIO); - if (IS_ERR(bs->bh)) - return PTR_ERR(bs->bh); + if (IS_ERR(bs->bh)) { + error = PTR_ERR(bs->bh); + bs->bh = NULL; + return error; + } ea_bdebug(bs->bh, "b_count=%d, refcount=%d", atomic_read(&(bs->bh->b_count)), le32_to_cpu(BHDR(bs->bh)->h_refcount)); |