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Don't trust the port in the source address of requests.

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At least one client gets it wrong: always send to the client port for
clients, and the server port for relays.
This commit is contained in:
Simon Kelley
2012-03-12 11:56:22 +00:00
parent 2a82db4caf
commit 1d0f91c4a9
3 changed files with 35 additions and 15 deletions
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19
src/dhcp6.c
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@@ -75,6 +75,7 @@ void dhcp6_packet(time_t now)
ssize_t sz;
struct ifreq ifr;
struct iname *tmp;
unsigned short port;
msg.msg_control = control_u.control6;
msg.msg_controllen = sizeof(control_u);
@@ -84,7 +85,7 @@ void dhcp6_packet(time_t now)
msg.msg_iov = &daemon->dhcp_packet;
msg.msg_iovlen = 1;
if ((sz = recv_dhcp_packet(daemon->dhcp6fd, &msg)) == -1 || sz <= 4)
if ((sz = recv_dhcp_packet(daemon->dhcp6fd, &msg)) == -1)
return;
for (cmptr = CMSG_FIRSTHDR(&msg); cmptr; cmptr = CMSG_NXTHDR(&msg, cmptr))
@@ -134,15 +135,23 @@ void dhcp6_packet(time_t now)
lease_prune(NULL, now); /* lose any expired leases */
sz = dhcp6_reply(parm.current, if_index, ifr.ifr_name, &parm.fallback,
sz, IN6_IS_ADDR_MULTICAST(&from.sin6_addr), now);
port = dhcp6_reply(parm.current, if_index, ifr.ifr_name, &parm.fallback,
sz, IN6_IS_ADDR_MULTICAST(&from.sin6_addr), now);
lease_update_file(now);
lease_update_dns();
if (sz != 0)
while (sendto(daemon->dhcp6fd, daemon->outpacket.iov_base, sz, 0, (struct sockaddr *)&from, sizeof(from)) == -1 &&
/* The port in the source address of the original request should
be correct, but at least once client sends from the server port,
so we explicitly send to the client port to a client, and the
server port to a relay. */
if (port != 0)
{
from.sin6_port = htons(port);
while (sendto(daemon->dhcp6fd, daemon->outpacket.iov_base, save_counter(0),
0, (struct sockaddr *)&from, sizeof(from)) == -1 &&
retry_send());
}
}
static int complete_context6(struct in6_addr *local, int prefix,