usbip: network: Fix unaligned member access

gcc 9 warns:

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);
      |                                ^~~~~~~~~~~~~

and similarly for other calls to usbip_net_pack_uint{16,32}_t().

These fields are unaligned because they are declared as part of a
packed structure.  Functions operating on the structure will use the
appropriate accessors for unaligned data if necessary, but there
doesn't seem to be a way to declare functions as taking a pointer
to a unaligned scalar.

Instead, change these functions to take a pointer of type void * and
to memcpy() the unaligned value in and out of a local variable.

Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Gbp-Pq: Topic bugfix/all
Gbp-Pq: Name usbip-network-fix-unaligned-member-access.patch

diff --git a/tools/usb/usbip/src/usbip_network.c b/tools/usb/usbip/src/usbip_network.c
index d595d72693fbba5d1e59fde6ded3d79b3c33c26f..02ec1e62ff2b3c42b1fa16aa818349517cd2b51c 100644 (file)
--- a/tools/usb/usbip/src/usbip_network.c
+++ b/tools/usb/usbip/src/usbip_network.c
@@ -50,28 +50,30 @@ 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)
+void usbip_net_pack_uint32_t(int pack, void *num)
 {
        uint32_t i;
 
+       memcpy(&i, num, sizeof(i));
        if (pack)
-               i = htonl(*num);
+               i = htonl(i);
        else
-               i = ntohl(*num);
+               i = ntohl(i);
 
-       *num = i;
+       memcpy(num, &i, sizeof(i));
 }
 
-void usbip_net_pack_uint16_t(int pack, uint16_t *num)
+void usbip_net_pack_uint16_t(int pack, void *num)
 {
        uint16_t i;
 
+       memcpy(&i, num, sizeof(i));
        if (pack)
-               i = htons(*num);
+               i = htons(i);
        else
-               i = ntohs(*num);
+               i = ntohs(i);
 
-       *num = i;
+       memcpy(num, &i, sizeof(i));
 }
 
 void usbip_net_pack_usb_device(int pack, struct usbip_usb_device *udev)

diff --git a/tools/usb/usbip/src/usbip_network.h b/tools/usb/usbip/src/usbip_network.h
index 555215eae43e9ee9fd75d789cdb2250d9b62086a..fb1bb1dfd12101c0ef35c1698cf83b4d1372c7af 100644 (file)
--- a/tools/usb/usbip/src/usbip_network.h
+++ b/tools/usb/usbip/src/usbip_network.h
@@ -166,8 +166,8 @@ struct op_devlist_reply_extra {
        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);
+void usbip_net_pack_uint32_t(int pack, void *num);
+void usbip_net_pack_uint16_t(int pack, void *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);