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[dhcp] Verify server identifier on ProxyDHCPACKs 

Perform the same test for a matching DHCP_SERVER_IDENTIFIER on
ProxyDHCPACKs as we do for DHCPACKs.  Otherwise, a retransmitted
DHCPACK can end up being treated as the ProxyDHCPACK.

I have a vague and unsettling memory that this test was deliberately
omitted, but I can't remember why, and can't find anything in the VC
logs.
This commit is contained in:
Michael Brown 2008-06-30 17:56:37 -07:00
parent 25450dc59c
commit fdb8481de1
1 changed files with 25 additions and 7 deletions
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32
src/net/udp/dhcp.c
View File

@ -685,6 +685,7 @@ static void dhcp_store_dhcpoffer ( struct dhcp_session *dhcp,
*/
static void dhcp_rx_dhcpoffer ( struct dhcp_session *dhcp,
struct dhcp_settings *dhcpoffer ) {
struct in_addr server_id;
char vci[9]; /* "PXEClient" */
int len;
uint8_t ignore_proxy = 0;
@ -692,7 +693,8 @@ static void dhcp_rx_dhcpoffer ( struct dhcp_session *dhcp,
/* Check for presence of DHCP server ID */
if ( dhcppkt_fetch ( &dhcpoffer->dhcppkt, DHCP_SERVER_IDENTIFIER,
NULL, 0 ) != sizeof ( struct in_addr ) ) {
&server_id, sizeof ( server_id ) )
!= sizeof ( server_id ) ) {
DBGC ( dhcp, "DHCP %p received DHCPOFFER %p missing server "
"identifier\n", dhcp, dhcpoffer );
return;
@ -700,8 +702,9 @@ static void dhcp_rx_dhcpoffer ( struct dhcp_session *dhcp,
/* If there is an IP address, it's a normal DHCPOFFER */
if ( dhcpoffer->dhcppkt.dhcphdr->yiaddr.s_addr != 0 ) {
DBGC ( dhcp, "DHCP %p received DHCPOFFER %p has IP address\n",
dhcp, dhcpoffer );
DBGC ( dhcp, "DHCP %p received DHCPOFFER %p from %s has IP "
"address\n",
dhcp, dhcpoffer, inet_ntoa ( server_id ) );
dhcp_store_dhcpoffer ( dhcp, dhcpoffer, &dhcp->dhcpoffer );
}
@ -713,8 +716,9 @@ static void dhcp_rx_dhcpoffer ( struct dhcp_session *dhcp,
vci, sizeof ( vci ) );
if ( ( len >= ( int ) sizeof ( vci ) ) &&
( strncmp ( "PXEClient", vci, sizeof ( vci ) ) == 0 ) ) {
DBGC ( dhcp, "DHCP %p received DHCPOFFER %p is a "
"ProxyDHCPOFFER\n", dhcp, dhcpoffer );
DBGC ( dhcp, "DHCP %p received DHCPOFFER %p from %s is a "
"ProxyDHCPOFFER\n",
dhcp, dhcpoffer, inet_ntoa ( server_id ) );
dhcp_store_dhcpoffer ( dhcp, dhcpoffer,
&dhcp->proxydhcpoffer );
}
@ -802,8 +806,8 @@ static void dhcp_rx_dhcpack ( struct dhcp_session *dhcp,
dhcppkt_fetch ( &dhcpack->dhcppkt, DHCP_SERVER_IDENTIFIER,
&ack_server_id, sizeof ( ack_server_id ) );
if ( offer_server_id.s_addr != ack_server_id.s_addr ) {
DBGC ( dhcp, "DHCP %p ignoring DHCPACK with wrong server ID\n",
dhcp );
DBGC ( dhcp, "DHCP %p ignoring DHCPACK with wrong server ID "
"%s\n", dhcp, inet_ntoa ( ack_server_id ) );
return;
}
@ -830,8 +834,22 @@ static void dhcp_rx_dhcpack ( struct dhcp_session *dhcp,
*/
static void dhcp_rx_proxydhcpack ( struct dhcp_session *dhcp,
struct dhcp_settings *proxydhcpack ) {
struct in_addr offer_server_id = { 0 };
struct in_addr ack_server_id = { 0 };
int rc;
/* Verify server ID matches */
assert ( dhcp->proxydhcpoffer != NULL );
dhcppkt_fetch ( &dhcp->proxydhcpoffer->dhcppkt, DHCP_SERVER_IDENTIFIER,
&offer_server_id, sizeof ( offer_server_id ) );
dhcppkt_fetch ( &proxydhcpack->dhcppkt, DHCP_SERVER_IDENTIFIER,
&ack_server_id, sizeof ( ack_server_id ) );
if ( offer_server_id.s_addr != ack_server_id.s_addr ) {
DBGC ( dhcp, "DHCP %p ignoring ProxyDHCPACK with wrong server "
"ID %s\n", dhcp, inet_ntoa ( ack_server_id ) );
return;
}
/* Rename settings */
proxydhcpack->settings.name = PROXYDHCP_SETTINGS_NAME;