From: Ben Hutchings <ben@decadent.org.uk>
Date: Thu, 28 Jan 2016 01:16:31 +0000 (+0000)
Subject: Fix memory leak in dhcpv6_add_server_cand in case odhcp6c_insert_state fails
X-Git-Tag: debian/1.1+git20160131-1~8^2~3
X-Git-Url: https://git.decadent.org.uk/gitweb/?a=commitdiff_plain;h=b0d1c5805a6b76c3b198728cdfd93e351d5eb196;p=odhcp6c.git

Fix memory leak in dhcpv6_add_server_cand in case odhcp6c_insert_state fails

If we fail to store information from the new server, the associated
NA and PD options will never be freed.  An attacker could use this
for denial-of-service.

Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---

diff --git a/src/dhcpv6.c b/src/dhcpv6.c
index cfa3f29..c2a3e3d 100644
--- a/src/dhcpv6.c
+++ b/src/dhcpv6.c
@@ -1362,6 +1362,7 @@ static void dhcpv6_handle_ia_status_code(const enum dhcpv6_msg orig,
 	}
 }
 
+// Note this always takes ownership of cand->ia_na and cand->ia_pd
 static void dhcpv6_add_server_cand(const struct dhcpv6_server_cand *cand)
 {
 	size_t cand_len, i;
@@ -1384,7 +1385,10 @@ static void dhcpv6_add_server_cand(const struct dhcpv6_server_cand *cand)
 			break;
 	}
 
-	odhcp6c_insert_state(STATE_SERVER_CAND, i * sizeof(*c), cand, sizeof(*cand));
+	if (odhcp6c_insert_state(STATE_SERVER_CAND, i * sizeof(*c), cand, sizeof(*cand))) {
+		free(cand->ia_na);
+		free(cand->ia_pd);
+	}
 }
 
 static void dhcpv6_clear_all_server_cand(void)