[PATCH 36/64] scsi: ibmvscsi: Avoid multi-field memset() overflow by aiming at srp

Kees Cook
2021-07-27T21:16:59Z

In preparation for FORTIFY_SOURCE performing compile-time and run-time
field bounds checking for memset(), avoid intentionally writing across
neighboring fields.

Instead of writing beyond the end of evt_struct->iu.srp.cmd, target the
upper union (evt_struct->iu.srp) instead, as that's what is being wiped.

Signed-off-by: Kees Cook <keescook@chromium.org>
---
drivers/scsi/ibmvscsi/ibmvscsi.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/scsi/ibmvscsi/ibmvscsi.c b/drivers/scsi/ibmvscsi/ibmvscsi.c
index e6a3eaaa57d9..7e8beb42d2d3 100644
--- a/drivers/scsi/ibmvscsi/ibmvscsi.c
+++ b/drivers/scsi/ibmvscsi/ibmvscsi.c
@@ -1055,8 +1055,8 @@ static int ibmvscsi_queuecommand_lck(struct scsi_cmnd *cmnd,
return SCSI_MLQUEUE_HOST_BUSY;

/* Set up the actual SRP IU */
+ memset(&evt_struct->iu.srp, 0x00, SRP_MAX_IU_LEN);
srp_cmd = &evt_struct->iu.srp.cmd;
- memset(srp_cmd, 0x00, SRP_MAX_IU_LEN);
srp_cmd->opcode = SRP_CMD;
memcpy(srp_cmd->cdb, cmnd->cmnd, sizeof(srp_cmd->cdb));
int_to_scsilun(lun, &srp_cmd->lun);
--
2.30.2