From: Roy Marples <roy@marples.name>
Date: Fri, 7 Feb 2014 14:57:19 +0000 (+0000)
Subject: Ignore netlink messages with an our of range pid.
X-Git-Tag: v6.3.0~36
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=119265612a49f20daa35e4c9de30a79c1c0dee80;p=thirdparty%2Fdhcpcd.git

Ignore netlink messages with an our of range pid.
---

diff --git a/if-linux.c b/if-linux.c
index 11c68740..fe69fc95 100644
--- a/if-linux.c
+++ b/if-linux.c
@@ -243,6 +243,18 @@ err_netlink(struct nlmsghdr *nlm)
 	return -1;
 }
 
+/* Work out the maximum pid size */
+static inline long long
+get_max_pid_t()
+{
+
+    if (sizeof(pid_t) == sizeof(short))		return SHRT_MAX;
+    if (sizeof(pid_t) == sizeof(int))		return INT_MAX;
+    if (sizeof(pid_t) == sizeof(long))		return LONG_MAX;
+    if (sizeof(pid_t) == sizeof(long long))	return LLONG_MAX;
+    abort();
+}
+
 static int
 link_route(struct nlmsghdr *nlm)
 {
@@ -263,9 +275,15 @@ link_route(struct nlmsghdr *nlm)
 	rtm = NLMSG_DATA(nlm);
 	if (rtm->rtm_type != RTN_UNICAST ||
 	    rtm->rtm_table != RT_TABLE_MAIN ||
-	    rtm->rtm_family != AF_INET ||
-	    nlm->nlmsg_pid == (uint32_t)getpid())
+	    rtm->rtm_family != AF_INET)
 		return 1;
+	/* Ignore messages generated by us.
+	 * For some reason we get messages generated by us
+	 * with a very large value in nlmsg_pid that seems to be
+	 * sequentially changing. Is there a better test for this? */
+	if (nlm->nlmsg_pid > get_max_pid_t())
+		return 1;
+
 	rta = (struct rtattr *)(void *)((char *)rtm +NLMSG_ALIGN(sizeof(*rtm)));
 	len = NLMSG_PAYLOAD(nlm, sizeof(*rtm));
 	memset(&rt, 0, sizeof(rt));
@@ -328,8 +346,6 @@ link_addr(struct nlmsghdr *nlm)
 		errno = EBADMSG;
 		return -1;
 	}
-//	if (nlm->nlmsg_pid == (uint32_t)getpid())
-//		return 1;
 	ifa = NLMSG_DATA(nlm);
 	if (if_indextoname(ifa->ifa_index, ifn) == NULL)
 		return -1;
@@ -508,6 +524,7 @@ link_netlink(struct nlmsghdr *nlm)
 int
 manage_link(int fd)
 {
+
 	return get_netlink(fd, MSG_DONTWAIT, &link_netlink);
 }