From: Roy Marples <roy@marples.name>
Date: Mon, 25 Apr 2016 13:03:52 +0000 (+0000)
Subject: We can only check rtm_pid for the correct pid - other messages
X-Git-Tag: v6.11.0~76
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ff3431567b6d858ed7696125315fd39b31083b96;p=thirdparty%2Fdhcpcd.git

We can only check rtm_pid for the correct pid - other messages
do not have this sadly.
---

diff --git a/if-bsd.c b/if-bsd.c
index 7ce4001c..4283e36c 100644
--- a/if-bsd.c
+++ b/if-bsd.c
@@ -1246,26 +1246,6 @@ if_managelink(struct dhcpcd_ctx *ctx)
 	e = msg + bytes;
 	for (p = msg; p < e; p += rtm->rtm_msglen) {
 		rtm = (void *)p;
-		if (rtm->rtm_type == RTM_MISS)
-			continue;
-		/* Ignore messages generated by us */
-		if (rtm->rtm_pid == getpid()) {
-			ctx->options &= ~DHCPCD_RTM_PPID;
-			continue;
-		}
-		/* Ignore messages sent by the parent process after forking */
-		if ((ctx->options & (DHCPCD_RTM_PPID | DHCPCD_DAEMONISED)) ==
-		    (DHCPCD_RTM_PPID | DHCPCD_DAEMONISED) &&
-		    rtm->rtm_pid == ctx->ppid)
-		{
-			/* If this is the last successful message sent clear
-			 * the check flag as it's possible another process could
-			 * re-use the same pid and also manipulate the kernel
-			 * routing table. */
-			if (rtm->rtm_seq == ctx->pseq)
-				ctx->options &= ~DHCPCD_RTM_PPID;
-			continue;
-		}
 		switch(rtm->rtm_type) {
 #ifdef RTM_IFANNOUNCE
 		case RTM_IFANNOUNCE:
@@ -1311,6 +1291,25 @@ if_managelink(struct dhcpcd_ctx *ctx)
 		case RTM_ADD:
 		case RTM_CHANGE:
 		case RTM_DELETE:
+			/* Ignore messages generated by us */
+			if (rtm->rtm_pid == getpid()) {
+				ctx->options &= ~DHCPCD_RTM_PPID;
+				continue;
+			}
+			/* Ignore messages sent by the parent after forking */
+			if ((ctx->options &
+			    (DHCPCD_RTM_PPID | DHCPCD_DAEMONISED)) ==
+			    (DHCPCD_RTM_PPID | DHCPCD_DAEMONISED) &&
+			    rtm->rtm_pid == ctx->ppid)
+			{
+				/* If this is the last successful message sent,
+				 * clear the check flag as it's possible another
+				 * process could re-use the same pid and also
+				 * manipulate therouting table. */
+				if (rtm->rtm_seq == ctx->pseq)
+					ctx->options &= ~DHCPCD_RTM_PPID;
+				continue;
+			}
 			cp = (void *)(rtm + 1);
 			sa = (void *)cp;
 			switch (sa->sa_family) {
@@ -1360,6 +1359,9 @@ if_managelink(struct dhcpcd_ctx *ctx)
 #endif
 		case RTM_DELADDR:	/* FALLTHROUGH */
 		case RTM_NEWADDR:
+			/* XXX We have no way of knowing who generated these
+			 * messages wich truely sucks because we want to
+			 * avoid listening to our own delete messages. */
 			ifam = (void *)p;
 			ifp = if_findindex(ctx->ifaces, ifam->ifam_index);
 			if (ifp == NULL)