diff options
| -rw-r--r-- | src/libsystemd-network/dhcp-network.c | 7 | ||||
| -rw-r--r-- | src/libsystemd-network/dhcp-packet.c | 14 | ||||
| -rw-r--r-- | src/libsystemd-network/sd-dhcp-client.c | 15 |
3 files changed, 12 insertions, 24 deletions
diff --git a/src/libsystemd-network/dhcp-network.c b/src/libsystemd-network/dhcp-network.c index 8bfb2d50af..a9a15b4d5a 100644 --- a/src/libsystemd-network/dhcp-network.c +++ b/src/libsystemd-network/dhcp-network.c @@ -34,11 +34,14 @@ int dhcp_network_bind_raw_socket(int index, union sockaddr_union *link) { struct sock_filter filter[] = { + BPF_STMT(BPF_LD + BPF_W + BPF_LEN, 0), /* A <- packet length */ + BPF_JUMP(BPF_JMP + BPF_JGE + BPF_K, sizeof(DHCPPacket), 1, 0), /* packet >= DHCPPacket ? */ + BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */ BPF_STMT(BPF_LD + BPF_B + BPF_ABS, offsetof(DHCPPacket, ip.protocol)), /* A <- IP protocol */ - BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, IPPROTO_UDP, 1, 0), /* IP protocol = UDP? */ + BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, IPPROTO_UDP, 1, 0), /* IP protocol == UDP ? */ BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */ BPF_STMT(BPF_LD + BPF_H + BPF_ABS, offsetof(DHCPPacket, udp.dest)), /* A <- UDP destination port */ - BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, DHCP_PORT_CLIENT, 1, 0), /* UDP destination port = DHCP client? */ + BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, DHCP_PORT_CLIENT, 1, 0), /* UDP destination port == DHCP client port ? */ BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */ BPF_STMT(BPF_RET + BPF_K, 65535), /* return all */ }; diff --git a/src/libsystemd-network/dhcp-packet.c b/src/libsystemd-network/dhcp-packet.c index 0549f575ac..102ed096af 100644 --- a/src/libsystemd-network/dhcp-packet.c +++ b/src/libsystemd-network/dhcp-packet.c @@ -113,13 +113,6 @@ int dhcp_packet_verify_headers(DHCPPacket *packet, size_t len, bool checksum) { /* IP */ - if (len < DHCP_IP_SIZE) { - log_dhcp_client(client, "ignoring packet: packet (%zu bytes) " - " smaller than IP header (%u bytes)", len, - DHCP_IP_SIZE); - return -EINVAL; - } - if (packet->ip.version != IPVERSION) { log_dhcp_client(client, "ignoring packet: not IPv4"); return -EINVAL; @@ -152,13 +145,6 @@ int dhcp_packet_verify_headers(DHCPPacket *packet, size_t len, bool checksum) { return -EINVAL; } - if (len < DHCP_IP_UDP_SIZE) { - log_dhcp_client(client, "ignoring packet: packet (%zu bytes) " - " smaller than IP+UDP header (%u bytes)", len, - DHCP_IP_UDP_SIZE); - return -EINVAL; - } - if (len < hdrlen + be16toh(packet->udp.len)) { log_dhcp_client(client, "ignoring packet: packet (%zu bytes) " "smaller than expected (%zu) by UDP header", len, diff --git a/src/libsystemd-network/sd-dhcp-client.c b/src/libsystemd-network/sd-dhcp-client.c index 5824e6ee91..722f862832 100644 --- a/src/libsystemd-network/sd-dhcp-client.c +++ b/src/libsystemd-network/sd-dhcp-client.c @@ -931,12 +931,6 @@ static int client_handle_message(sd_dhcp_client *client, DHCPMessage *message, assert(client->event); assert(message); - if (len < DHCP_MESSAGE_SIZE) { - log_dhcp_client(client, "message too small (%d bytes): " - "ignoring", len); - return 0; - } - if (be32toh(message->magic) != DHCP_MAGIC_COOKIE) { log_dhcp_client(client, "not a DHCP message: ignoring"); return 0; @@ -1081,7 +1075,11 @@ static int client_receive_message_udp(sd_event_source *s, int fd, return -ENOMEM; len = read(fd, message, buflen); - if (len < 0) + if (len < 0) { + log_dhcp_client(client, "could not receive message from UDP " + "socket: %s", strerror(errno)); + return 0; + } else if ((size_t)len < sizeof(DHCPMessage)) return 0; return client_handle_message(client, message, len); @@ -1122,7 +1120,8 @@ static int client_receive_message_raw(sd_event_source *s, int fd, log_dhcp_client(client, "could not receive message from raw " "socket: %s", strerror(errno)); return 0; - } + } else if ((size_t)len < sizeof(DHCPPacket)) + return 0; for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) { if (cmsg->cmsg_level == SOL_PACKET && cmsg->cmsg_type == PACKET_AUXDATA) { |