From: mpi <mpi@openbsd.org>
Date: Wed, 3 Jun 2015 08:10:53 +0000 (+0000)
Subject: Explicitly request the sockaddr_dl when doing a RTM_GET rather than
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=f3b11628a009ccfbc47a504210e1737cf43509bc;p=openbsd

Explicitly request the sockaddr_dl when doing a RTM_GET rather than
assuming that it will be in the gateway sa.

Fixes a regression introduced with the support of multiple connected
routes, found the hardway by deraadt@.

ok claudio@
---

diff --git a/usr.sbin/arp/arp.c b/usr.sbin/arp/arp.c
index fcd61491e3b..e2d36cd2e76 100644
--- a/usr.sbin/arp/arp.c
+++ b/usr.sbin/arp/arp.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: arp.c,v 1.63 2015/01/16 06:40:15 deraadt Exp $ */
+/*	$OpenBSD: arp.c,v 1.64 2015/06/03 08:10:53 mpi Exp $ */
 /*	$NetBSD: arp.c,v 1.12 1995/04/24 13:25:18 cgd Exp $ */
 
 /*
@@ -75,6 +75,7 @@ int file(char *);
 int get(const char *);
 int getinetaddr(const char *, struct in_addr *);
 void getsocket(void);
+int rtget(struct sockaddr_inarp **, struct sockaddr_dl **);
 int rtmsg(int);
 int set(int, char **);
 void usage(void);
@@ -254,6 +255,7 @@ getsocket(void)
 struct sockaddr_in	so_mask = { 8, 0, 0, { 0xffffffff } };
 struct sockaddr_inarp	blank_sin = { sizeof(blank_sin), AF_INET }, sin_m;
 struct sockaddr_dl	blank_sdl = { sizeof(blank_sdl), AF_LINK }, sdl_m;
+struct sockaddr_dl	ifp_m = { sizeof(&ifp_m), AF_LINK };
 time_t			expire_time;
 int			flags, export_only, doing_proxy, found_entry;
 struct	{
@@ -319,12 +321,11 @@ set(int argc, char *argv[])
 	}
 
 tryagain:
-	if (rtmsg(RTM_GET) < 0) {
+	if (rtget(&sin, &sdl)) {
 		warn("%s", host);
 		return (1);
 	}
-	sin = (struct sockaddr_inarp *)((char *)rtm + rtm->rtm_hdrlen);
-	sdl = (struct sockaddr_dl *)(ROUNDUP(sin->sin_len) + (char *)sin);
+
 	if (sin->sin_addr.s_addr == sin_m.sin_addr.s_addr) {
 		if (sdl->sdl_family == AF_LINK &&
 		    (rtm->rtm_flags & RTF_LLINFO) &&
@@ -412,15 +413,13 @@ delete(const char *host, const char *info)
 	if (getinetaddr(host, &sin->sin_addr) == -1)
 		return (1);
 tryagain:
-	if (rtmsg(RTM_GET) < 0) {
+	if (rtget(&sin, &sdl) < 0) {
 		warn("%s", host);
 		return (1);
 	}
-	sin = (struct sockaddr_inarp *)((char *)rtm + rtm->rtm_hdrlen);
-	sdl = (struct sockaddr_dl *)(ROUNDUP(sin->sin_len) + (char *)sin);
 	if (sin->sin_addr.s_addr == sin_m.sin_addr.s_addr) {
 		if (sdl->sdl_family == AF_LINK && rtm->rtm_flags & RTF_LLINFO) {
-			if (rtm->rtm_flags & (RTF_LOCAL|RTF_BROADCAST))
+			if (rtm->rtm_flags & RTF_LOCAL)
 				return (0);
 		    	if (!(rtm->rtm_flags & RTF_GATEWAY))
 				switch (sdl->sdl_type) {
@@ -493,8 +492,6 @@ search(in_addr_t addr, void (*action)(struct sockaddr_dl *sdl,
 		rtm = (struct rt_msghdr *)next;
 		if (rtm->rtm_version != RTM_VERSION)
 			continue;
-		if (rtm->rtm_flags & RTF_BROADCAST)
-			continue;
 		sin = (struct sockaddr_inarp *)(next + rtm->rtm_hdrlen);
 		sdl = (struct sockaddr_dl *)(sin + 1);
 		if (addr) {
@@ -558,7 +555,7 @@ print_entry(struct sockaddr_dl *sdl, struct sockaddr_inarp *sin,
 	printf("%-*.*s %-*.*s %*.*s", addrwidth, addrwidth, host,
 	    llwidth, llwidth, ether_str(sdl), ifwidth, ifwidth, ifname);
 
-	if (rtm->rtm_flags & (RTF_PERMANENT_ARP|RTF_LOCAL|RTF_BROADCAST))
+	if (rtm->rtm_flags & (RTF_PERMANENT_ARP|RTF_LOCAL))
 		printf(" %-10.10s", "permanent");
 	else if (rtm->rtm_rmx.rmx_expire == 0)
 		printf(" %-10.10s", "static");
@@ -654,7 +651,7 @@ rtmsg(int cmd)
 		}
 		/* FALLTHROUGH */
 	case RTM_GET:
-		rtm->rtm_addrs |= RTA_DST;
+		rtm->rtm_addrs |= (RTA_DST | RTA_IFP);
 	}
 
 #define NEXTADDR(w, s)					\
@@ -666,6 +663,7 @@ rtmsg(int cmd)
 	NEXTADDR(RTA_DST, sin_m);
 	NEXTADDR(RTA_GATEWAY, sdl_m);
 	NEXTADDR(RTA_NETMASK, so_mask);
+	NEXTADDR(RTA_IFP, ifp_m);
 
 	rtm->rtm_msglen = cp - (char *)&m_rtmsg;
 doit:
@@ -688,6 +686,48 @@ doit:
 	return (0);
 }
 
+int
+rtget(struct sockaddr_inarp **sinp, struct sockaddr_dl **sdlp)
+{
+	struct rt_msghdr *rtm = &(m_rtmsg.m_rtm);
+	struct sockaddr_inarp *sin = NULL;
+	struct sockaddr_dl *sdl = NULL;
+	struct sockaddr *sa;
+	char *cp;
+	int i;
+
+	if (rtmsg(RTM_GET) < 0)
+		return (1);
+
+	if (rtm->rtm_addrs) {
+		cp = ((char *)rtm + rtm->rtm_hdrlen);
+		for (i = 1; i; i <<= 1) {
+			if (i & rtm->rtm_addrs) {
+				sa = (struct sockaddr *)cp;
+				switch (i) {
+				case RTA_DST:
+					sin = (struct sockaddr_inarp *)sa;
+					break;
+				case RTA_IFP:
+					sdl = (struct sockaddr_dl *)sa;
+					break;
+				default:
+					break;
+				}
+				cp += ROUNDUP(sa->sa_len);
+			}
+		}
+	}
+
+	if (sin == NULL || sdl == NULL)
+		return (1);
+
+	*sinp = sin;
+	*sdlp = sdl;
+
+	return (0);
+}
+
 int
 getinetaddr(const char *host, struct in_addr *inap)
 {
diff --git a/usr.sbin/ndp/ndp.c b/usr.sbin/ndp/ndp.c
index ce75ef718a0..46c12698287 100644
--- a/usr.sbin/ndp/ndp.c
+++ b/usr.sbin/ndp/ndp.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ndp.c,v 1.60 2015/04/18 18:28:38 deraadt Exp $	*/
+/*	$OpenBSD: ndp.c,v 1.61 2015/06/03 08:10:53 mpi Exp $	*/
 /*	$KAME: ndp.c,v 1.101 2002/07/17 08:46:33 itojun Exp $	*/
 
 /*
@@ -134,6 +134,7 @@ static char *ether_str(struct sockaddr_dl *);
 int ndp_ether_aton(char *, u_char *);
 void usage(void);
 int rtmsg(int);
+int rtget(struct sockaddr_in6 **, struct sockaddr_dl **);
 void ifinfo(char *, int, char **);
 void rtrlist(void);
 void plist(void);
@@ -343,6 +344,7 @@ getsocket(void)
 struct	sockaddr_in6 so_mask = {sizeof(so_mask), AF_INET6 };
 struct	sockaddr_in6 blank_sin = {sizeof(blank_sin), AF_INET6 }, sin_m;
 struct	sockaddr_dl blank_sdl = {sizeof(blank_sdl), AF_LINK }, sdl_m;
+struct	sockaddr_dl ifp_m = { sizeof(&ifp_m), AF_LINK };
 time_t	expire_time;
 int	flags, found_entry;
 struct	{
@@ -400,12 +402,12 @@ set(int argc, char **argv)
 			flags |= RTF_ANNOUNCE;
 		argv++;
 	}
-	if (rtmsg(RTM_GET) < 0) {
+
+	if (rtget(&sin, &sdl)) {
 		errx(1, "RTM_GET(%s) failed", host);
 		/* NOTREACHED */
 	}
-	sin = (struct sockaddr_in6 *)((char *)rtm + rtm->rtm_hdrlen);
-	sdl = (struct sockaddr_dl *)(ROUNDUP(sin->sin6_len) + (char *)sin);
+
 	if (IN6_ARE_ADDR_EQUAL(&sin->sin6_addr, &sin_m.sin6_addr)) {
 		if (sdl->sdl_family == AF_LINK &&
 		    (rtm->rtm_flags & RTF_LLINFO) &&
@@ -499,12 +501,12 @@ delete(char *host)
 		    htons(((struct sockaddr_in6 *)res->ai_addr)->sin6_scope_id);
 	}
 #endif
-	if (rtmsg(RTM_GET) < 0) {
+
+	if (rtget(&sin, &sdl)) {
 		errx(1, "RTM_GET(%s) failed", host);
 		/* NOTREACHED */
 	}
-	sin = (struct sockaddr_in6 *)((char *)rtm + rtm->rtm_hdrlen);
-	sdl = (struct sockaddr_dl *)(ROUNDUP(sin->sin6_len) + (char *)sin);
+
 	if (IN6_ARE_ADDR_EQUAL(&sin->sin6_addr, &sin_m.sin6_addr)) {
 		if (sdl->sdl_family == AF_LINK && rtm->rtm_flags & RTF_LLINFO) {
 			if (rtm->rtm_flags & (RTF_LOCAL|RTF_BROADCAST))
@@ -832,7 +834,7 @@ rtmsg(int cmd)
 #endif
 		/* FALLTHROUGH */
 	case RTM_GET:
-		rtm->rtm_addrs |= RTA_DST;
+		rtm->rtm_addrs |= (RTA_DST | RTA_IFP);
 	}
 #define NEXTADDR(w, s) \
 	if (rtm->rtm_addrs & (w)) { \
@@ -844,6 +846,7 @@ rtmsg(int cmd)
 	memset(&so_mask.sin6_addr, 0xff, sizeof(so_mask.sin6_addr));
 	NEXTADDR(RTA_NETMASK, so_mask);
 #endif
+	NEXTADDR(RTA_IFP, ifp_m);
 
 	rtm->rtm_msglen = cp - (char *)&m_rtmsg;
 doit:
@@ -866,6 +869,48 @@ doit:
 	return (0);
 }
 
+int
+rtget(struct sockaddr_in6 **sinp, struct sockaddr_dl **sdlp)
+{
+	struct rt_msghdr *rtm = &(m_rtmsg.m_rtm);
+	struct sockaddr_in6 *sin = NULL;
+	struct sockaddr_dl *sdl = NULL;
+	struct sockaddr *sa;
+	char *cp;
+	int i;
+
+	if (rtmsg(RTM_GET) < 0)
+		return (1);
+
+	if (rtm->rtm_addrs) {
+		cp = ((char *)rtm + rtm->rtm_hdrlen);
+		for (i = 1; i; i <<= 1) {
+			if (i & rtm->rtm_addrs) {
+				sa = (struct sockaddr *)cp;
+				switch (i) {
+				case RTA_DST:
+					sin = (struct sockaddr_in6 *)sa;
+					break;
+				case RTA_IFP:
+					sdl = (struct sockaddr_dl *)sa;
+					break;
+				default:
+					break;
+				}
+				cp += ROUNDUP(sa->sa_len);
+			}
+		}
+	}
+
+	if (sin == NULL || sdl == NULL)
+		return (1);
+
+	*sinp = sin;
+	*sdlp = sdl;
+
+	return (0);
+}
+
 void
 ifinfo(char *ifname, int argc, char **argv)
 {