usbip: Fix unsafe unaligned pointer usage

Fix unsafe unaligned pointer usage in usbip network interfaces. usbip tool
build fails with new gcc -Werror=address-of-packed-member checks.

usbip_network.c: In function ‘usbip_net_pack_usb_device’:
usbip_network.c:79:32: error: taking address of packed member of ‘struct usbip_usb_device’ may result in an unaligned pointer value [-Werror=address-of-packed-member]
   79 |  usbip_net_pack_uint32_t(pack, &udev->busnum);

Fix with minor changes to pass by value instead of by address.

Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
Link: https://lore.kernel.org/r/20200109012416.2875-1-skhan@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tools/usb/usbip/src/usbip_network.c

@@ -50,39 +50,39 @@ void usbip_setup_port_number(char *arg)
 	info("using port %d (\"%s\")", usbip_port, usbip_port_string);
 }
 
-void usbip_net_pack_uint32_t(int pack, uint32_t *num)
+uint32_t usbip_net_pack_uint32_t(int pack, uint32_t num)
 {
 	uint32_t i;
 
 	if (pack)
-		i = htonl(*num);
+		i = htonl(num);
 	else
-		i = ntohl(*num);
+		i = ntohl(num);
 
-	*num = i;
+	return i;
 }
 
-void usbip_net_pack_uint16_t(int pack, uint16_t *num)
+uint16_t usbip_net_pack_uint16_t(int pack, uint16_t num)
 {
 	uint16_t i;
 
 	if (pack)
-		i = htons(*num);
+		i = htons(num);
 	else
-		i = ntohs(*num);
+		i = ntohs(num);
 
-	*num = i;
+	return i;
 }
 
 void usbip_net_pack_usb_device(int pack, struct usbip_usb_device *udev)
 {
-	usbip_net_pack_uint32_t(pack, &udev->busnum);
-	usbip_net_pack_uint32_t(pack, &udev->devnum);
-	usbip_net_pack_uint32_t(pack, &udev->speed);
+	udev->busnum = usbip_net_pack_uint32_t(pack, udev->busnum);
+	udev->devnum = usbip_net_pack_uint32_t(pack, udev->devnum);
+	udev->speed = usbip_net_pack_uint32_t(pack, udev->speed);
 
-	usbip_net_pack_uint16_t(pack, &udev->idVendor);
-	usbip_net_pack_uint16_t(pack, &udev->idProduct);
-	usbip_net_pack_uint16_t(pack, &udev->bcdDevice);
+	udev->idVendor = usbip_net_pack_uint16_t(pack, udev->idVendor);
+	udev->idProduct = usbip_net_pack_uint16_t(pack, udev->idProduct);
+	udev->bcdDevice = usbip_net_pack_uint16_t(pack, udev->bcdDevice);
 }
 
 void usbip_net_pack_usb_interface(int pack __attribute__((unused)),
@@ -129,6 +129,14 @@ ssize_t usbip_net_send(int sockfd, void *buff, size_t bufflen)
 	return usbip_net_xmit(sockfd, buff, bufflen, 1);
 }
 
+static inline void usbip_net_pack_op_common(int pack,
+					    struct op_common *op_common)
+{
+	op_common->version = usbip_net_pack_uint16_t(pack, op_common->version);
+	op_common->code = usbip_net_pack_uint16_t(pack, op_common->code);
+	op_common->status = usbip_net_pack_uint32_t(pack, op_common->status);
+}
+
 int usbip_net_send_op_common(int sockfd, uint32_t code, uint32_t status)
 {
 	struct op_common op_common;
@@ -140,7 +148,7 @@ int usbip_net_send_op_common(int sockfd, uint32_t code, uint32_t status)
 	op_common.code    = code;
 	op_common.status  = status;
 
-	PACK_OP_COMMON(1, &op_common);
+	usbip_net_pack_op_common(1, &op_common);
 
 	rc = usbip_net_send(sockfd, &op_common, sizeof(op_common));
 	if (rc < 0) {
@@ -164,7 +172,7 @@ int usbip_net_recv_op_common(int sockfd, uint16_t *code, int *status)
 		goto err;
 	}
 
-	PACK_OP_COMMON(0, &op_common);
+	usbip_net_pack_op_common(0, &op_common);
 
 	if (op_common.version != USBIP_VERSION) {
 		err("USBIP Kernel and tool version mismatch: %d %d:",

tools/usb/usbip/src/usbip_network.h

@@ -32,12 +32,6 @@ struct op_common {
 
 } __attribute__((packed));
 
-#define PACK_OP_COMMON(pack, op_common)  do {\
-	usbip_net_pack_uint16_t(pack, &(op_common)->version);\
-	usbip_net_pack_uint16_t(pack, &(op_common)->code);\
-	usbip_net_pack_uint32_t(pack, &(op_common)->status);\
-} while (0)
-
 /* ---------------------------------------------------------------------- */
 /* Dummy Code */
 #define OP_UNSPEC	0x00
@@ -163,11 +157,11 @@ struct op_devlist_reply_extra {
 } while (0)
 
 #define PACK_OP_DEVLIST_REPLY(pack, reply)  do {\
-	usbip_net_pack_uint32_t(pack, &(reply)->ndev);\
+	(reply)->ndev = usbip_net_pack_uint32_t(pack, (reply)->ndev);\
 } while (0)
 
-void usbip_net_pack_uint32_t(int pack, uint32_t *num);
-void usbip_net_pack_uint16_t(int pack, uint16_t *num);
+uint32_t usbip_net_pack_uint32_t(int pack, uint32_t num);
+uint16_t usbip_net_pack_uint16_t(int pack, uint16_t num);
 void usbip_net_pack_usb_device(int pack, struct usbip_usb_device *udev);
 void usbip_net_pack_usb_interface(int pack, struct usbip_usb_interface *uinf);