diff options
authorDavid Gibson <david@gibson.dropbear.id.au>2012-02-24 01:23:28 +0100
committerJan Kiszka <jan.kiszka@siemens.com>2012-02-27 14:55:07 +0100
commit90d7416ab13113ccd3891435eea8715c5f503460 (patch)
parentb87ffa163185e339f9f9f1e6dbc561e0f990442d (diff)
slirp: Fix assertion failure on rejected DHCP requests
The guest network stack might DHCPREQUEST an address that the slirp built in dhcp server can't let it have - for example if the guest has an old leases file from another network configuration. In this case the dhcp server should and does reject the request and prepares to send a DHCPNAK to the client. However, in this case the daddr variable in bootp_reply() is set to Shortly afterwards, it unconditionally attempts to pre-insert the new client address into the ARP table. This causes an assertion failure in arp_address_add() because of the address. According to RFC2131, DHCPNAK messages for clients on the same subnet must be sent to the broadcast address (S3.2, subpoint 2). Cc: Jan Kiszka <jan.kiszka@siemens.com> Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
1 files changed, 2 insertions, 1 deletions
diff --git a/slirp/bootp.c b/slirp/bootp.c
index efd1fe777a..64eac7d101 100644
--- a/slirp/bootp.c
+++ b/slirp/bootp.c
@@ -200,7 +200,8 @@ static void bootp_reply(Slirp *slirp, const struct bootp_t *bp)
daddr.sin_addr = preq_addr;
memcpy(bc->macaddr, client_ethaddr, ETH_ALEN);
} else {
- daddr.sin_addr.s_addr = 0;
+ /* DHCPNAKs should be sent to broadcast */
+ daddr.sin_addr.s_addr = 0xffffffff;
} else {
bc = find_addr(slirp, &daddr.sin_addr, bp->bp_hwaddr);