[PATCH 6.1] xfs: add bounds checking to xlog_recover_process_data

[PATCH 6.1] xfs: add bounds checking to xlog_recover_process_data

[Bin Lan]

From: lei lu <llfamsec@gmail.com>

[ Upstream commit fb63435b7c7dc112b1ae1baea5486e0a6e27b196 ]

There is a lack of verification of the space occupied by fixed members
of xlog_op_header in the xlog_recover_process_data.

We can create a crafted image to trigger an out of bounds read by
following these steps:
    1) Mount an image of xfs, and do some file operations to leave records
    2) Before umounting, copy the image for subsequent steps to simulate
       abnormal exit. Because umount will ensure that tail_blk and
       head_blk are the same, which will result in the inability to enter
       xlog_recover_process_data
    3) Write a tool to parse and modify the copied image in step 2
    4) Make the end of the xlog_op_header entries only 1 byte away from
       xlog_rec_header->h_size
    5) xlog_rec_header->h_num_logops++
    6) Modify xlog_rec_header->h_crc

Fix:
Add a check to make sure there is sufficient space to access fixed members
of xlog_op_header.

Signed-off-by: lei lu <llfamsec@gmail.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>
Signed-off-by: Bin Lan <bin.lan.cn@windriver.com>
---
 fs/xfs/xfs_log_recover.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/fs/xfs/xfs_log_recover.c b/fs/xfs/xfs_log_recover.c
index affe94356ed1..006a376c34b2 100644
--- a/fs/xfs/xfs_log_recover.c
+++ b/fs/xfs/xfs_log_recover.c
@@ -2439,7 +2439,10 @@ xlog_recover_process_data(
 
 		ohead = (struct xlog_op_header *)dp;
 		dp += sizeof(*ohead);
-		ASSERT(dp <= end);
+		if (dp > end) {
+			xfs_warn(log->l_mp, "%s: op header overrun", __func__);
+			return -EFSCORRUPTED;
+		}
 
 		/* errors will abort recovery */
 		error = xlog_recover_process_ophdr(log, rhash, rhead, ohead,
-- 
2.34.1

Re: [PATCH 6.1] xfs: add bounds checking to xlog_recover_process_data

[Sasha Levin]

[ Sasha's backport helper bot ]

Hi,

The upstream commit SHA1 provided is correct: fb63435b7c7dc112b1ae1baea5486e0a6e27b196

WARNING: Author mismatch between patch and upstream commit:
Backport author: Bin Lan <bin.lan.cn@windriver.com>
Commit author: lei lu <llfamsec@gmail.com>


Status in newer kernel trees:
6.12.y | Present (exact SHA1)
6.11.y | Present (exact SHA1)
6.6.y | Not found
6.1.y | Not found

Note: The patch differs from the upstream commit:
---
--- -	2024-11-27 09:15:10.118544781 -0500
+++ /tmp/tmp.yXhwFlxu6p	2024-11-27 09:15:10.108180884 -0500
@@ -1,3 +1,5 @@
+[ Upstream commit fb63435b7c7dc112b1ae1baea5486e0a6e27b196 ]
+
 There is a lack of verification of the space occupied by fixed members
 of xlog_op_header in the xlog_recover_process_data.
 
@@ -22,15 +24,16 @@
 Reviewed-by: Dave Chinner <dchinner@redhat.com>
 Reviewed-by: Darrick J. Wong <djwong@kernel.org>
 Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>
+Signed-off-by: Bin Lan <bin.lan.cn@windriver.com>
 ---
  fs/xfs/xfs_log_recover.c | 5 ++++-
  1 file changed, 4 insertions(+), 1 deletion(-)
 
 diff --git a/fs/xfs/xfs_log_recover.c b/fs/xfs/xfs_log_recover.c
-index 4fe627991e865..409b645ce7995 100644
+index affe94356ed1..006a376c34b2 100644
 --- a/fs/xfs/xfs_log_recover.c
 +++ b/fs/xfs/xfs_log_recover.c
-@@ -2489,7 +2489,10 @@ xlog_recover_process_data(
+@@ -2439,7 +2439,10 @@ xlog_recover_process_data(
  
  		ohead = (struct xlog_op_header *)dp;
  		dp += sizeof(*ohead);
@@ -42,3 +45,6 @@
  
  		/* errors will abort recovery */
  		error = xlog_recover_process_ophdr(log, rhash, rhead, ohead,
+-- 
+2.34.1
+
---

Results of testing on various branches:

| Branch                    | Patch Apply | Build Test |
|---------------------------|-------------|------------|
| stable/linux-6.1.y        |  Success    |  Success   |