From: Hans Dedecker <dedeckeh@gmail.com>
Date: Tue, 8 Dec 2020 17:43:38 +0000 (+0100)
Subject: dhcpv6: harden reconfigure logic
X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=0ffa3a31f7146d320214f431291c1196070a010f;p=project%2Fodhcp6c.git

dhcpv6: harden reconfigure logic

Check if a valid DHCPv6 message is returned by dhcpv6_request in
dhcpv6_poll_reconfigure as only RENEW/REBIND/INFORMATION REQUEST
messages can trigger the transmission of these messages in reply
to a RECONFIGURE

Signed-off-by: Hans Dedecker <dedeckeh@gmail.com>
---

diff --git a/src/dhcpv6.c b/src/dhcpv6.c
index 312e7aa..b9eac43 100644
--- a/src/dhcpv6.c
+++ b/src/dhcpv6.c
@@ -849,8 +849,21 @@ int dhcpv6_poll_reconfigure(void)
 {
 	int ret = dhcpv6_request(DHCPV6_MSG_UNKNOWN);
 
-	if (ret != -1)
+	switch (ret) {
+	/*
+	 * Only RENEW/REBIND/INFORMATION REQUEST
+	 * messaage transmission can be requested
+	 * by a RECONFIGURE
+	 */
+	case DHCPV6_MSG_RENEW:
+	case DHCPV6_MSG_REBIND:
+	case DHCPV6_MSG_INFO_REQ:
 		ret = dhcpv6_request(ret);
+		break;
+
+	default:
+		break;
+	}
 
 	return ret;
 }