scsi: sg: fixup infoleak when using SG_GET_REQUEST_TABLE

commit 3e00974 upstream.

When calling SG_GET_REQUEST_TABLE ioctl only a half-filled table is
returned; the remaining part will then contain stale kernel memory
information.  This patch zeroes out the entire table to avoid this
issue.

Signed-off-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Bart Van Assche <bart.vanassche@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/scsi/sg.c

@@ -865,7 +865,6 @@ sg_fill_request_table(Sg_fd *sfp, sg_req_info_t *rinfo)
 	list_for_each_entry(srp, &sfp->rq_list, entry) {
 		if (val > SG_MAX_QUEUE)
 			break;
-		memset(&rinfo[val], 0, SZ_SG_REQ_INFO);
 		rinfo[val].req_state = srp->done + 1;
 		rinfo[val].problem =
 			srp->header.masked_status &
@@ -1082,8 +1081,8 @@ sg_ioctl(struct file *filp, unsigned int cmd_in, unsigned long arg)
 		else {
 			sg_req_info_t *rinfo;
 
-			rinfo = kmalloc(SZ_SG_REQ_INFO * SG_MAX_QUEUE,
-								GFP_KERNEL);
+			rinfo = kzalloc(SZ_SG_REQ_INFO * SG_MAX_QUEUE,
+					GFP_KERNEL);
 			if (!rinfo)
 				return -ENOMEM;
 			read_lock_irqsave(&sfp->rq_list_lock, iflags);