diff options
| -rw-r--r-- | libnetutils/packet.c | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/libnetutils/packet.c b/libnetutils/packet.c index e53a4c84f..9ecdd4f4e 100644 --- a/libnetutils/packet.c +++ b/libnetutils/packet.c @@ -218,6 +218,20 @@ int receive_packet(int s, struct dhcp_msg *msg) * to construct the pseudo header used in the checksum calculation. */ dhcp_size = ntohs(packet.udp.len) - sizeof(packet.udp); + /* + * check validity of dhcp_size. + * 1) cannot be negative or zero. + * 2) src buffer contains enough bytes to copy + * 3) cannot exceed destination buffer + */ + if ((dhcp_size <= 0) || + ((int)(nread - sizeof(struct iphdr) - sizeof(struct udphdr)) < dhcp_size) || + ((int)sizeof(struct dhcp_msg) < dhcp_size)) { +#if VERBOSE + ALOGD("Malformed Packet"); +#endif + return -1; + } saddr = packet.ip.saddr; daddr = packet.ip.daddr; nread = ntohs(packet.ip.tot_len); |