swrap: Fix strict aliasing issues in swrap_pcap_packet_init()

Signed-off-by: Andreas Schneider <asn@samba.org>
Reviewed-by: Ralph Boehme <slow@samba.org>

diff --git a/src/socket_wrapper.c b/src/socket_wrapper.c
index e59e5017f09e2177c50538768b4ac4f52af21009..193f1f0672d2e0d883a4aeaaeba2fb29e238b1b4 100644 (file)
--- a/src/socket_wrapper.c
+++ b/src/socket_wrapper.c
@@ -2461,14 +2461,20 @@ static uint8_t *swrap_pcap_packet_init(struct timeval *tval,
                                       int unreachable,
                                       size_t *_packet_len)
 {
-       uint8_t *base;
-       uint8_t *buf;
-       struct swrap_packet_frame *frame;
-       union swrap_packet_ip *ip;
+       uint8_t *base = NULL;
+       uint8_t *buf = NULL;
+       union {
+               uint8_t *ptr;
+               struct swrap_packet_frame *frame;
+       } f;
+       union {
+               uint8_t *ptr;
+               union swrap_packet_ip *ip;
+       } i;
        union swrap_packet_payload *pay;
        size_t packet_len;
        size_t alloc_len;
-       size_t nonwire_len = sizeof(*frame);
+       size_t nonwire_len = sizeof(struct swrap_packet_frame);
        size_t wire_hdr_len = 0;
        size_t wire_len = 0;
        size_t ip_hdr_len = 0;
@@ -2490,7 +2496,7 @@ static uint8_t *swrap_pcap_packet_init(struct timeval *tval,
                dest_in = (const struct sockaddr_in *)(const void *)dest;
                src_port = src_in->sin_port;
                dest_port = dest_in->sin_port;
-               ip_hdr_len = sizeof(ip->v4);
+               ip_hdr_len = sizeof(i.ip->v4);
                break;
 #ifdef HAVE_IPV6
        case AF_INET6:
@@ -2498,7 +2504,7 @@ static uint8_t *swrap_pcap_packet_init(struct timeval *tval,
                dest_in6 = (const struct sockaddr_in6 *)(const void *)dest;
                src_port = src_in6->sin6_port;
                dest_port = dest_in6->sin6_port;
-               ip_hdr_len = sizeof(ip->v6);
+               ip_hdr_len = sizeof(i.ip->v6);
                break;
 #endif
        default:
@@ -2554,39 +2560,40 @@ static uint8_t *swrap_pcap_packet_init(struct timeval *tval,
        }
 
        buf = base;
+       f.ptr = buf;
+
+       f.frame->seconds                = tval->tv_sec;
+       f.frame->micro_seconds  = tval->tv_usec;
+       f.frame->recorded_length        = wire_len - icmp_truncate_len;
+       f.frame->full_length    = wire_len - icmp_truncate_len;
 
-       frame = (struct swrap_packet_frame *)(void *)buf;
-       frame->seconds          = tval->tv_sec;
-       frame->micro_seconds    = tval->tv_usec;
-       frame->recorded_length  = wire_len - icmp_truncate_len;
-       frame->full_length      = wire_len - icmp_truncate_len;
        buf += SWRAP_PACKET_FRAME_SIZE;
 
-       ip = (union swrap_packet_ip *)(void *)buf;
+       i.ptr = buf;
        switch (src->sa_family) {
        case AF_INET:
-               ip->v4.ver_hdrlen       = 0x45; /* version 4 and 5 * 32 bit words */
-               ip->v4.tos              = 0x00;
-               ip->v4.packet_length    = htons(wire_len - icmp_truncate_len);
-               ip->v4.identification   = htons(0xFFFF);
-               ip->v4.flags            = 0x40; /* BIT 1 set - means don't fragment */
-               ip->v4.fragment         = htons(0x0000);
-               ip->v4.ttl              = 0xFF;
-               ip->v4.protocol         = protocol;
-               ip->v4.hdr_checksum     = htons(0x0000);
-               ip->v4.src_addr         = src_in->sin_addr.s_addr;
-               ip->v4.dest_addr        = dest_in->sin_addr.s_addr;
+               i.ip->v4.ver_hdrlen     = 0x45; /* version 4 and 5 * 32 bit words */
+               i.ip->v4.tos            = 0x00;
+               i.ip->v4.packet_length  = htons(wire_len - icmp_truncate_len);
+               i.ip->v4.identification = htons(0xFFFF);
+               i.ip->v4.flags          = 0x40; /* BIT 1 set - means don't fragment */
+               i.ip->v4.fragment       = htons(0x0000);
+               i.ip->v4.ttl            = 0xFF;
+               i.ip->v4.protocol       = protocol;
+               i.ip->v4.hdr_checksum   = htons(0x0000);
+               i.ip->v4.src_addr       = src_in->sin_addr.s_addr;
+               i.ip->v4.dest_addr      = dest_in->sin_addr.s_addr;
                buf += SWRAP_PACKET_IP_V4_SIZE;
                break;
 #ifdef HAVE_IPV6
        case AF_INET6:
-               ip->v6.ver_prio         = 0x60; /* version 4 and 5 * 32 bit words */
-               ip->v6.flow_label_high  = 0x00;
-               ip->v6.flow_label_low   = 0x0000;
-               ip->v6.payload_length   = htons(wire_len - icmp_truncate_len); /* TODO */
-               ip->v6.next_header      = protocol;
-               memcpy(ip->v6.src_addr, src_in6->sin6_addr.s6_addr, 16);
-               memcpy(ip->v6.dest_addr, dest_in6->sin6_addr.s6_addr, 16);
+               i.ip->v6.ver_prio               = 0x60; /* version 4 and 5 * 32 bit words */
+               i.ip->v6.flow_label_high        = 0x00;
+               i.ip->v6.flow_label_low = 0x0000;
+               i.ip->v6.payload_length = htons(wire_len - icmp_truncate_len); /* TODO */
+               i.ip->v6.next_header    = protocol;
+               memcpy(i.ip->v6.src_addr, src_in6->sin6_addr.s6_addr, 16);
+               memcpy(i.ip->v6.dest_addr, dest_in6->sin6_addr.s6_addr, 16);
                buf += SWRAP_PACKET_IP_V6_SIZE;
                break;
 #endif
@@ -2600,21 +2607,23 @@ static uint8_t *swrap_pcap_packet_init(struct timeval *tval,
                        pay->icmp4.code         = 0x01; /* host unreachable */
                        pay->icmp4.checksum     = htons(0x0000);
                        pay->icmp4.unused       = htonl(0x00000000);
+
                        buf += SWRAP_PACKET_PAYLOAD_ICMP4_SIZE;
 
                        /* set the ip header in the ICMP payload */
-                       ip = (union swrap_packet_ip *)(void *)buf;
-                       ip->v4.ver_hdrlen       = 0x45; /* version 4 and 5 * 32 bit words */
-                       ip->v4.tos              = 0x00;
-                       ip->v4.packet_length    = htons(wire_len - icmp_hdr_len);
-                       ip->v4.identification   = htons(0xFFFF);
-                       ip->v4.flags            = 0x40; /* BIT 1 set - means don't fragment */
-                       ip->v4.fragment         = htons(0x0000);
-                       ip->v4.ttl              = 0xFF;
-                       ip->v4.protocol         = icmp_protocol;
-                       ip->v4.hdr_checksum     = htons(0x0000);
-                       ip->v4.src_addr         = dest_in->sin_addr.s_addr;
-                       ip->v4.dest_addr        = src_in->sin_addr.s_addr;
+                       i.ptr = buf;
+                       i.ip->v4.ver_hdrlen     = 0x45; /* version 4 and 5 * 32 bit words */
+                       i.ip->v4.tos            = 0x00;
+                       i.ip->v4.packet_length  = htons(wire_len - icmp_hdr_len);
+                       i.ip->v4.identification = htons(0xFFFF);
+                       i.ip->v4.flags          = 0x40; /* BIT 1 set - means don't fragment */
+                       i.ip->v4.fragment       = htons(0x0000);
+                       i.ip->v4.ttl            = 0xFF;
+                       i.ip->v4.protocol       = icmp_protocol;
+                       i.ip->v4.hdr_checksum   = htons(0x0000);
+                       i.ip->v4.src_addr       = dest_in->sin_addr.s_addr;
+                       i.ip->v4.dest_addr      = src_in->sin_addr.s_addr;
+
                        buf += SWRAP_PACKET_IP_V4_SIZE;
 
                        src_port = dest_in->sin_port;
@@ -2629,14 +2638,15 @@ static uint8_t *swrap_pcap_packet_init(struct timeval *tval,
                        buf += SWRAP_PACKET_PAYLOAD_ICMP6_SIZE;
 
                        /* set the ip header in the ICMP payload */
-                       ip = (union swrap_packet_ip *)(void *)buf;
-                       ip->v6.ver_prio         = 0x60; /* version 4 and 5 * 32 bit words */
-                       ip->v6.flow_label_high  = 0x00;
-                       ip->v6.flow_label_low   = 0x0000;
-                       ip->v6.payload_length   = htons(wire_len - icmp_truncate_len); /* TODO */
-                       ip->v6.next_header      = protocol;
-                       memcpy(ip->v6.src_addr, dest_in6->sin6_addr.s6_addr, 16);
-                       memcpy(ip->v6.dest_addr, src_in6->sin6_addr.s6_addr, 16);
+                       i.ptr = buf;
+                       i.ip->v6.ver_prio               = 0x60; /* version 4 and 5 * 32 bit words */
+                       i.ip->v6.flow_label_high        = 0x00;
+                       i.ip->v6.flow_label_low = 0x0000;
+                       i.ip->v6.payload_length = htons(wire_len - icmp_truncate_len); /* TODO */
+                       i.ip->v6.next_header    = protocol;
+                       memcpy(i.ip->v6.src_addr, dest_in6->sin6_addr.s6_addr, 16);
+                       memcpy(i.ip->v6.dest_addr, src_in6->sin6_addr.s6_addr, 16);
+
                        buf += SWRAP_PACKET_IP_V6_SIZE;
 
                        src_port = dest_in6->sin6_port;