diff options
| -rw-r--r-- | gdhcp/client.c | 16 |
1 files changed, 9 insertions, 7 deletions
diff --git a/gdhcp/client.c b/gdhcp/client.c index 7efa7e45..82017692 100644 --- a/gdhcp/client.c +++ b/gdhcp/client.c @@ -1319,9 +1319,9 @@ static bool sanity_check(struct ip_udp_dhcp_packet *packet, int bytes) static int dhcp_recv_l2_packet(struct dhcp_packet *dhcp_pkt, int fd, struct sockaddr_in *dst_addr) { - int bytes; struct ip_udp_dhcp_packet packet; uint16_t check; + int bytes, tot_len; memset(&packet, 0, sizeof(packet)); @@ -1329,15 +1329,17 @@ static int dhcp_recv_l2_packet(struct dhcp_packet *dhcp_pkt, int fd, if (bytes < 0) return -1; - if (bytes < (int) (sizeof(packet.ip) + sizeof(packet.udp))) - return -1; - - if (bytes < ntohs(packet.ip.tot_len)) + tot_len = ntohs(packet.ip.tot_len); + if (bytes > tot_len) { + /* ignore any extra garbage bytes */ + bytes = tot_len; + } else if (bytes < tot_len) { /* packet is bigger than sizeof(packet), we did partial read */ return -1; + } - /* ignore any extra garbage bytes */ - bytes = ntohs(packet.ip.tot_len); + if (bytes < (int) (sizeof(packet.ip) + sizeof(packet.udp))) + return -1; if (!sanity_check(&packet, bytes)) return -1; |