2021-07-13 02:26:19

by yebin

[permalink] [raw]
Subject: [PATCH -next] ext4: Fix access uninitialized 'retval' in kmmpd

If (!ext4_has_feature_mmp(sb)) then goto 'wait_to_exit' label, but
retval not be uninitialized.

Fixes: 61bb4a1c417e ("ext4: fix possible UAF when remounting r/o a mmp-protected file system")
Signed-off-by: Ye Bin <[email protected]>
---
fs/ext4/mmp.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/ext4/mmp.c b/fs/ext4/mmp.c
index bc364c119af6..cebea4270817 100644
--- a/fs/ext4/mmp.c
+++ b/fs/ext4/mmp.c
@@ -138,7 +138,7 @@ static int kmmpd(void *data)
unsigned mmp_check_interval;
unsigned long last_update_time;
unsigned long diff;
- int retval;
+ int retval = 0;

mmp_block = le64_to_cpu(es->s_mmp_block);
mmp = (struct mmp_struct *)(bh->b_data);
--
2.31.1


2021-07-23 11:32:24

by Theodore Ts'o

[permalink] [raw]
Subject: Re: [PATCH -next] ext4: Fix access uninitialized 'retval' in kmmpd

On Tue, Jul 13, 2021 at 10:27:28AM +0800, Ye Bin wrote:
> If (!ext4_has_feature_mmp(sb)) then goto 'wait_to_exit' label, but
> retval not be uninitialized.
>
> Fixes: 61bb4a1c417e ("ext4: fix possible UAF when remounting r/o a mmp-protected file system")
> Signed-off-by: Ye Bin <[email protected]>

Thanks, applied with a slightly fixed up commit description.

- Ted