diff options
| -rw-r--r-- | sbin/dhcpleased/frontend.c | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/sbin/dhcpleased/frontend.c b/sbin/dhcpleased/frontend.c index 0c5d187e4c5..76313923dc8 100644 --- a/sbin/dhcpleased/frontend.c +++ b/sbin/dhcpleased/frontend.c @@ -1,4 +1,4 @@ -/* $OpenBSD: frontend.c,v 1.7 2021/03/19 07:43:27 florian Exp $ */ +/* $OpenBSD: frontend.c,v 1.8 2021/03/22 16:28:25 florian Exp $ */ /* * Copyright (c) 2017, 2021 Florian Obser <florian@openbsd.org> @@ -57,6 +57,7 @@ #include "checksum.h" #define ROUTE_SOCKET_BUF_SIZE 16384 +#define BOOTP_MIN_LEN 300 /* fixed bootp packet adds up to 300 */ struct bpf_ev { struct event ev; @@ -783,6 +784,7 @@ build_packet(uint8_t message_type, uint32_t xid, struct ether_addr *hw_address, static uint8_t dhcp_server_identifier[] = {DHO_DHCP_SERVER_IDENTIFIER, 4, 0, 0, 0, 0}; struct dhcp_hdr *hdr; + ssize_t len; uint8_t *p; char *c; @@ -834,7 +836,13 @@ build_packet(uint8_t message_type, uint32_t xid, struct ether_addr *hw_address, *p = DHO_END; p += 1; - return (p - dhcp_packet); + len = p - dhcp_packet; + + /* dhcp_packet is initialized with DHO_PADs */ + if (len < BOOTP_MIN_LEN) + len = BOOTP_MIN_LEN; + + return (len); } void |