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bug #34406 dhcp_option_hostname() can overflow the pbuf

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This commit is contained in:
goldsimon 2011-09-27 07:49:04 +02:00
parent 7524f9006e
commit cfb70bccc1
2 changed files with 15 additions and 9 deletions
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3
CHANGELOG
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@ -65,6 +65,9 @@ HISTORY
++ Bugfixes:
2011-09-27: Simon Goldschmidt
* dhcp.c: fixed bug #34406 dhcp_option_hostname() can overflow the pbuf
2011-09-24: Simon Goldschmidt
* mem.h: fixed bug #34377 MEM_SIZE_F is not defined if MEM_LIBC_MALLOC==1

21
src/core/dhcp.c
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@ -1028,10 +1028,6 @@ dhcp_renew(struct netif *netif)
dhcp_option(dhcp, DHCP_OPTION_MAX_MSG_SIZE, DHCP_OPTION_MAX_MSG_SIZE_LEN);
dhcp_option_short(dhcp, DHCP_MAX_MSG_LEN(netif));
#if LWIP_NETIF_HOSTNAME
dhcp_option_hostname(dhcp, netif);
#endif /* LWIP_NETIF_HOSTNAME */
#if 0
dhcp_option(dhcp, DHCP_OPTION_REQUESTED_IP, 4);
dhcp_option_long(dhcp, ntohl(dhcp->offered_ip_addr.addr));
@ -1041,6 +1037,11 @@ dhcp_renew(struct netif *netif)
dhcp_option(dhcp, DHCP_OPTION_SERVER_ID, 4);
dhcp_option_long(dhcp, ntohl(dhcp->server_ip_addr.addr));
#endif
#if LWIP_NETIF_HOSTNAME
dhcp_option_hostname(dhcp, netif);
#endif /* LWIP_NETIF_HOSTNAME */
/* append DHCP message trailer */
dhcp_option_trailer(dhcp);
@ -1303,8 +1304,11 @@ dhcp_option_hostname(struct dhcp *dhcp, struct netif *netif)
if (namelen > 0) {
u8_t len;
const char *p = netif->hostname;
LWIP_ASSERT("DHCP: hostname is too long!", namelen <= 255);
len = LWIP_MAX(namelen, 255);
/* Shrink len to available bytes (need 2 bytes for OPTION_HOSTNAME
and 1 byte for trailer) */
size_t available = DHCP_OPTIONS_LEN - dhcp->options_out_len - 3;
LWIP_ASSERT("DHCP: hostname is too long!", namelen <= available);
len = LWIP_MIN(namelen, available);
dhcp_option(dhcp, DHCP_OPTION_HOSTNAME, len);
while (len--) {
dhcp_option_byte(dhcp, *p++);
@ -1744,9 +1748,8 @@ dhcp_option_trailer(struct dhcp *dhcp)
LWIP_ASSERT("dhcp_option_trailer: dhcp->options_out_len < DHCP_OPTIONS_LEN\n", dhcp->options_out_len < DHCP_OPTIONS_LEN);
dhcp->msg_out->options[dhcp->options_out_len++] = DHCP_OPTION_END;
/* packet is too small, or not 4 byte aligned? */
while ((dhcp->options_out_len < DHCP_MIN_OPTIONS_LEN) || (dhcp->options_out_len & 3)) {
/* LWIP_DEBUGF(DHCP_DEBUG,("dhcp_option_trailer:dhcp->options_out_len=%"U16_F", DHCP_OPTIONS_LEN=%"U16_F, dhcp->options_out_len, DHCP_OPTIONS_LEN)); */
LWIP_ASSERT("dhcp_option_trailer: dhcp->options_out_len < DHCP_OPTIONS_LEN\n", dhcp->options_out_len < DHCP_OPTIONS_LEN);
while (((dhcp->options_out_len < DHCP_MIN_OPTIONS_LEN) || (dhcp->options_out_len & 3)) &&
(dhcp->options_out_len < DHCP_OPTIONS_LEN)) {
/* add a fill/padding byte */
dhcp->msg_out->options[dhcp->options_out_len++] = 0;
}