[PATCH 5.15/5.10] scsi: ufs: bsg: Set bsg_queue to NULL after removal

[PATCH 5.15/5.10] scsi: ufs: bsg: Set bsg_queue to NULL after removal

[Xiangyu Chen]

From: Guixin Liu <kanie@linux.alibaba.com>

[ Upstream commit 1e95c798d8a7f70965f0f88d4657b682ff0ec75f ]

Currently, this does not cause any issues, but I believe it is necessary to
set bsg_queue to NULL after removing it to prevent potential use-after-free
(UAF) access.

Signed-off-by: Guixin Liu <kanie@linux.alibaba.com>
Link: https://lore.kernel.org/r/20241218014214.64533-3-kanie@linux.alibaba.com
Reviewed-by: Avri Altman <avri.altman@wdc.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Xiangyu Chen <xiangyu.chen@windriver.com>
Signed-off-by: He Zhe <zhe.he@windriver.com>
---
Verified the build test.
---
 drivers/scsi/ufs/ufs_bsg.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/scsi/ufs/ufs_bsg.c b/drivers/scsi/ufs/ufs_bsg.c
index 16e8ddcf22fe..b8bbfd81b8ae 100644
--- a/drivers/scsi/ufs/ufs_bsg.c
+++ b/drivers/scsi/ufs/ufs_bsg.c
@@ -175,6 +175,7 @@ void ufs_bsg_remove(struct ufs_hba *hba)
 		return;
 
 	bsg_remove_queue(hba->bsg_queue);
+	hba->bsg_queue = NULL;
 
 	device_del(bsg_dev);
 	put_device(bsg_dev);
-- 
2.34.1

Re: [PATCH 5.15/5.10] scsi: ufs: bsg: Set bsg_queue to NULL after removal

[Sasha Levin]

[ Sasha's backport helper bot ]

Hi,

✅ All tests passed successfully. No issues detected.
No action required from the submitter.

The upstream commit SHA1 provided is correct: 1e95c798d8a7f70965f0f88d4657b682ff0ec75f

WARNING: Author mismatch between patch and upstream commit:
Backport author: Xiangyu Chen<xiangyu.chen@eng.windriver.com>
Commit author: Guixin Liu<kanie@linux.alibaba.com>

Status in newer kernel trees:
6.14.y | Present (exact SHA1)
6.13.y | Present (different SHA1: 9193bdc170cc)
6.12.y | Present (different SHA1: 88a01e9c9ad4)
6.6.y | Present (different SHA1: 5f782d4741bf)
6.1.y | Present (different SHA1: 5e7b6e44468c)
5.15.y | Not found

Note: The patch differs from the upstream commit:
---
1:  1e95c798d8a7f ! 1:  be0ecc3eb507b scsi: ufs: bsg: Set bsg_queue to NULL after removal
    @@ Metadata
      ## Commit message ##
         scsi: ufs: bsg: Set bsg_queue to NULL after removal
     
    +    [ Upstream commit 1e95c798d8a7f70965f0f88d4657b682ff0ec75f ]
    +
         Currently, this does not cause any issues, but I believe it is necessary to
         set bsg_queue to NULL after removing it to prevent potential use-after-free
         (UAF) access.
    @@ Commit message
         Link: https://lore.kernel.org/r/20241218014214.64533-3-kanie@linux.alibaba.com
         Reviewed-by: Avri Altman <avri.altman@wdc.com>
         Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
    +    Signed-off-by: Xiangyu Chen <xiangyu.chen@windriver.com>
    +    Signed-off-by: He Zhe <zhe.he@windriver.com>
     
    - ## drivers/ufs/core/ufs_bsg.c ##
    -@@ drivers/ufs/core/ufs_bsg.c: void ufs_bsg_remove(struct ufs_hba *hba)
    + ## drivers/scsi/ufs/ufs_bsg.c ##
    +@@ drivers/scsi/ufs/ufs_bsg.c: void ufs_bsg_remove(struct ufs_hba *hba)
      		return;
      
      	bsg_remove_queue(hba->bsg_queue);
---

Results of testing on various branches:

| Branch                    | Patch Apply | Build Test |
|---------------------------|-------------|------------|
| stable/linux-5.10.y       |  Success    |  Success   |
| stable/linux-5.15.y       |  Success    |  Success   |