Fuzzing of 5.10 stable branch reports a slab-out-of-bounds error in
ata_scsi_pass_thru.
The error is fixed in 5.18 by commit ce70fd9a551a ("scsi: core: Remove the
cmd field from struct scsi_request") upstream.
Backporting this commit would require significant changes to the code so
it is bettter to use a simple fix for that particular error.
The problem is that the length of the received SCSI command is not
validated if scsi_op == VARIABLE_LENGTH_CMD. It can lead to out-of-bounds
reading if the user sends a request with SCSI command of length less than
32.
Found by Linux Verification Center (linuxtesting.org) with Syzkaller.
Signed-off-by: Artem Sadovnikov <ancowi69@xxxxxxxxx>
Signed-off-by: Mikhail Ivanov <iwanov-23@xxxxx>
Signed-off-by: Mikhail Ukhin <mish.uxin2012@xxxxxxxxx>
---
v2: The new addresses were added and the text was updated.
v3: Checking has been moved to the function ata_scsi_var_len_cdb_xlat at
the request of Damien Le Moal.
v4: Extra opcode check removed.
drivers/ata/libata-scsi.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index dfa090ccd21c..38488bd813d1 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -3948,7 +3948,11 @@ static unsigned int ata_scsi_var_len_cdb_xlat(struct ata_queued_cmd *qc)
struct scsi_cmnd *scmd = qc->scsicmd;
const u8 *cdb = scmd->cmnd;
const u16 sa = get_unaligned_be16(&cdb[8]);
+ if (scmd->cmd_len < 32)
+ return 1;
+
/*
* if service action represents a ata pass-thru(32) command,
* then pass it to ata_scsi_pass_thru handler.
--
2.25.1
