[PATCH 1/1] scsi: Fix possible buffer overflows in storvsc_queuecommand

[Xiaohui Zhang]

From: Zhang Xiaohui <ruc_zhangxiaohui@xxxxxxx>

storvsc_queuecommand() calls memcpy() without checking
the destination size may trigger a buffer overflower,
which a local user could use to cause denial of service
or the execution of arbitrary code.
Fix it by putting the length check before calling memcpy().

Signed-off-by: Zhang Xiaohui <ruc_zhangxiaohui@xxxxxxx>
---
 drivers/scsi/storvsc_drv.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/scsi/storvsc_drv.c b/drivers/scsi/storvsc_drv.c
index 0c65fbd41..09b60a4c0 100644
--- a/drivers/scsi/storvsc_drv.c
+++ b/drivers/scsi/storvsc_drv.c
@@ -1729,6 +1729,8 @@ static int storvsc_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scmnd)
 
 	vm_srb->cdb_length = scmnd->cmd_len;
 
+	if (vm_srb->cdb_length > STORVSC_MAX_CMD_LEN)
+		vm_srb->cdb_length = STORVSC_MAX_CMD_LEN;
 	memcpy(vm_srb->cdb, scmnd->cmnd, vm_srb->cdb_length);
 
 	sgl = (struct scatterlist *)scsi_sglist(scmnd);
-- 
2.17.1