[SCSI] qla4xxx: overflow in qla4xxx_set_chap_entry()

We should cap the size of memcpy() because it comes from the network
and can't be trusted.

Fixes: 26ffd7b4 ('[SCSI] qla4xxx: Add support to set CHAP entries')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Vikas Chaudhary <vikas.chaudhary@qlogic.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

drivers/scsi/qla4xxx/ql4_os.c

@@ -861,6 +861,7 @@ static int qla4xxx_set_chap_entry(struct Scsi_Host *shost, void *data, int len)
 	int type;
 	int rem = len;
 	int rc = 0;
+	int size;
 
 	memset(&chap_rec, 0, sizeof(chap_rec));
 
@@ -875,12 +876,14 @@ static int qla4xxx_set_chap_entry(struct Scsi_Host *shost, void *data, int len)
 			chap_rec.chap_type = param_info->value[0];
 			break;
 		case ISCSI_CHAP_PARAM_USERNAME:
-			memcpy(chap_rec.username, param_info->value,
-			       param_info->len);
+			size = min_t(size_t, sizeof(chap_rec.username),
+				     param_info->len);
+			memcpy(chap_rec.username, param_info->value, size);
 			break;
 		case ISCSI_CHAP_PARAM_PASSWORD:
-			memcpy(chap_rec.password, param_info->value,
-			       param_info->len);
+			size = min_t(size_t, sizeof(chap_rec.password),
+				     param_info->len);
+			memcpy(chap_rec.password, param_info->value, size);
 			break;
 		case ISCSI_CHAP_PARAM_PASSWORD_LEN:
 			chap_rec.password_length = param_info->value[0];