input: UNIXSOCK: prevent unaligned pointer access

`struct ulogd_unixsock_packet_t` is packed, so taking the address of its
`struct iphdr payload` member may yield an unaligned pointer value.  We
only actually dereference the pointer to get the IP version, so replace
the pointer with a version variable and elsewhere use `pkt.payload`
directly.

Remove a couple of stray semicolons.

Signed-off-by: Jeremy Sowden <jeremy@azazel.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

diff --git a/input/packet/ulogd_inppkt_UNIXSOCK.c b/input/packet/ulogd_inppkt_UNIXSOCK.c
index 0080c6a067955a5ccedad6d2e8a2fbae09bf66b8..f1d15348ccb334f0232f104ac96dacb71d8b7866 100644 (file)
--- a/input/packet/ulogd_inppkt_UNIXSOCK.c
+++ b/input/packet/ulogd_inppkt_UNIXSOCK.c
@@ -371,7 +371,7 @@ struct ulogd_unixsock_option_t  {
 static int handle_packet(struct ulogd_pluginstance *upi, struct ulogd_unixsock_packet_t *pkt, uint16_t total_len)
 {
        char *data = NULL;
-       struct iphdr *ip;
+       unsigned int ip_version = pkt->payload.version;
        struct ulogd_key *ret = upi->output.keys;
        uint8_t oob_family;
        uint16_t payload_len;
@@ -387,22 +387,22 @@ static int handle_packet(struct ulogd_pluginstance *upi, struct ulogd_unixsock_p
 
        payload_len = ntohs(pkt->payload_length);
 
-       ip = &pkt->payload;
-       if (ip->version == 4)
+       if (ip_version == 4)
                oob_family = AF_INET;
-       else if (ip->version == 6)
+       else if (ip_version == 6)
                oob_family = AF_INET6;
-       else oob_family = 0;
+       else
+               oob_family = 0;
 
        okey_set_u8(&ret[UNIXSOCK_KEY_OOB_FAMILY], oob_family);
-       okey_set_ptr(&ret[UNIXSOCK_KEY_RAW_PCKT], ip);
+       okey_set_ptr(&ret[UNIXSOCK_KEY_RAW_PCKT], &pkt->payload);
        okey_set_u32(&ret[UNIXSOCK_KEY_RAW_PCKTLEN], payload_len);
 
        /* options */
        if (total_len > payload_len + sizeof(uint16_t)) {
                /* option starts at the next aligned address after the payload */
                new_offset = USOCK_ALIGN(payload_len);
-               options_start = (void*)ip + new_offset;
+               options_start = (void*)&pkt->payload + new_offset;
                data = options_start;
                total_len -= (options_start - (char*)pkt);
 
@@ -460,7 +460,7 @@ static int handle_packet(struct ulogd_pluginstance *upi, struct ulogd_unixsock_p
                                                "ulogd2: unknown option %d\n",
                                                option_number);
                                break;
-                       };
+                       }
                }
        }
 
@@ -666,7 +666,7 @@ static int unixsock_instance_read_cb(int fd, unsigned int what, void *param)
                }
 
                /* handle_packet has shifted data in buffer */
-       };
+       }
 
        return 0;
 }