scsi: sg: check length passed to SG_NEXT_CMD_LEN

commit bf33f87dd04c371ea33feb821b60d63d754e3124 upstream.

The user can control the size of the next command passed along, but the
value passed to the ioctl isn't checked against the usable max command
size.

Signed-off-by: Peter Chang <dpf@google.com>
Acked-by: Douglas Gilbert <dgilbert@interlog.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c
index 0becdb6e1ba08e933ed3c401874ef786f92e02bb..e50adf71022984d5ddc0707d1c5d97f519223817 100644 (file)
--- a/drivers/scsi/sg.c
+++ b/drivers/scsi/sg.c
@@ -1017,6 +1017,8 @@ sg_ioctl(struct file *filp, unsigned int cmd_in, unsigned long arg)
                result = get_user(val, ip);
                if (result)
                        return result;
+               if (val > SG_MAX_CDB_SIZE)
+                       return -ENOMEM;
                sfp->next_cmd_len = (val > 0) ? val : 0;
                return 0;
        case SG_GET_VERSION_NUM: