msg_controllen has to be CMSG_SPACE so that the kernel can account for

each cmsg_len (ie. msg_controllen = sum of CMSG_ALIGN(cmsg_len).  This
works now that kernel fd passing has been fixed to accept a bit of
sloppiness because of this ABI repair.
lots of discussion with kettenis

2 files changed, 18 insertions, 30 deletions

diff --git a/usr.sbin/bind/lib/isc/unix/privsep_fdpass.c b/usr.sbin/bind/lib/isc/unix/privsep_fdpass.c
index 444889a8074..5a59e0bda73 100644
--- a/usr.sbin/bind/lib/isc/unix/privsep_fdpass.c
+++ b/usr.sbin/bind/lib/isc/unix/privsep_fdpass.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: privsep_fdpass.c,v 1.6 2008/03/15 16:33:58 deraadt Exp $	*/
+/*	$OpenBSD: privsep_fdpass.c,v 1.7 2008/03/24 16:11:02 deraadt Exp $	*/
 
 /*
  * Copyright 2001 Niels Provos <provos@citi.umich.edu>
@@ -61,7 +61,7 @@ send_fd(int sock, int fd)
 
 	if (fd >= 0) {
 		msg.msg_control = (caddr_t)&cmsgbuf.buf;
-		msg.msg_controllen = CMSG_LEN(sizeof(int));
+		msg.msg_controllen = sizeof(cmsgbuf.buf);
 		cmsg = CMSG_FIRSTHDR(&msg);
 		cmsg->cmsg_len = CMSG_LEN(sizeof(int));
 		cmsg->cmsg_level = SOL_SOCKET;
@@ -102,7 +102,7 @@ receive_fd(int sock)
 	msg.msg_iov = &vec;
 	msg.msg_iovlen = 1;
 	msg.msg_control = &cmsgbuf.buf;
-	msg.msg_controllen = CMSG_LEN(sizeof(int));
+	msg.msg_controllen = sizeof(cmsgbuf.buf);
 
 	if ((n = recvmsg(sock, &msg, 0)) == -1)
 		warn("%s: recvmsg", __func__);
diff --git a/usr.sbin/bind/lib/isc/unix/socket.c b/usr.sbin/bind/lib/isc/unix/socket.c
index 74003115a47..5f6583dc5e4 100644
--- a/usr.sbin/bind/lib/isc/unix/socket.c
+++ b/usr.sbin/bind/lib/isc/unix/socket.c
@@ -190,10 +190,8 @@ struct isc_socket {
 #endif
 
 	char			*recvcmsgbuf;
-	ISC_SOCKADDR_LEN_T	recvcmsgbufspace;
 	ISC_SOCKADDR_LEN_T	recvcmsgbuflen;
 	char			*sendcmsgbuf;
-	ISC_SOCKADDR_LEN_T	sendcmsgbufspace;
 	ISC_SOCKADDR_LEN_T	sendcmsgbuflen;
 };
 
@@ -513,14 +511,11 @@ cmsg_space(ISC_SOCKADDR_LEN_T len) {
 	 * XXX: The buffer length is an ad-hoc value, but should be enough
 	 * in a practical sense.
 	 */
-	union {
-		struct cmsghdr hdr;
-		char buf[cmsg_sizeof(struct cmsghdr) + 1024];
-	};
+	char dummybuf[sizeof(struct cmsghdr) + 1024];
 
 	memset(&msg, 0, sizeof(msg));
 	msg.msg_control = dummybuf;
-	msg.msg_controllen = cmsg_len(sizeof(cmsg_sizeof(struct cmsghdr) + 1024));
+	msg.msg_controllen = sizeof(dummybuf);
 
 	cmsgp = (struct cmsghdr *)dummybuf;
 	cmsgp->cmsg_len = cmsg_len(len);
@@ -726,7 +721,7 @@ build_msghdr_send(isc_socket_t *sock, isc_socketevent_t *dev,
 			   "sendto pktinfo data, ifindex %u",
 			   dev->pktinfo.ipi6_ifindex);
 
-		msg->msg_controllen = cmsg_len(sizeof(struct in6_pktinfo));
+		msg->msg_controllen = cmsg_space(sizeof(struct in6_pktinfo));
 		INSIST(msg->msg_controllen <= sock->sendcmsgbuflen);
 		msg->msg_control = (void *)sock->sendcmsgbuf;
 
@@ -867,7 +862,7 @@ build_msghdr_recv(isc_socket_t *sock, isc_socketevent_t *dev,
 	msg->msg_flags = 0;
 #if defined(USE_CMSG)
 	if (sock->type == isc_sockettype_udp) {
-		msg->msg_control = sock->recvcmsgbuf;	
+		msg->msg_control = sock->recvcmsgbuf;
 		msg->msg_controllen = sock->recvcmsgbuflen;
 	}
 #endif /* USE_CMSG */
@@ -1262,7 +1257,7 @@ allocate_socket(isc_socketmgr_t *manager, isc_sockettype_t type,
 {
 	isc_socket_t *sock;
 	isc_result_t result;
-	ISC_SOCKADDR_LEN_T cmsgbuflen, cmsgbufspace;
+	ISC_SOCKADDR_LEN_T cmsgbuflen;
 
 	sock = isc_mem_get(manager->mctx, sizeof(*sock));
 
@@ -1287,33 +1282,26 @@ allocate_socket(isc_socketmgr_t *manager, isc_sockettype_t type,
 	 * set up cmsg buffers
 	 */
 	cmsgbuflen = 0;
-	cmsgbufspace = 0;
 #if defined(USE_CMSG) && defined(ISC_PLATFORM_HAVEIN6PKTINFO)
-	cmsgbuflen = cmsgbufspace + cmsg_len(sizeof(struct in6_pktinfo));
-	cmsgbufspace += cmsg_space(sizeof(struct in6_pktinfo));
+	cmsgbuflen = cmsg_space(sizeof(struct in6_pktinfo));
 #endif
 #if defined(USE_CMSG) && defined(SO_TIMESTAMP)
-	cmsgbuflen = cmsgbufspace + cmsg_len(sizeof(struct timeval));
-	cmsgbufspace += cmsg_space(sizeof(struct timeval));
+	cmsgbuflen += cmsg_space(sizeof(struct timeval));
 #endif
 	sock->recvcmsgbuflen = cmsgbuflen;
-	sock->recvcmsgbufspace = cmsgbufspace;
-	if (sock->recvcmsgbufspace != 0U) {
-		sock->recvcmsgbuf = isc_mem_get(manager->mctx, cmsgbufspace);
+	if (sock->recvcmsgbuflen != 0U) {
+		sock->recvcmsgbuf = isc_mem_get(manager->mctx, cmsgbuflen);
 		if (sock->recvcmsgbuf == NULL)
 			goto error;
 	}
 
 	cmsgbuflen = 0;
-	cmsgbufspace = 0;
 #if defined(USE_CMSG) && defined(ISC_PLATFORM_HAVEIN6PKTINFO)
-	cmsgbuflen = cmsgbufspace + cmsg_len(sizeof(struct in6_pktinfo));
-	cmsgbufspace += cmsg_space(sizeof(struct in6_pktinfo));
+	cmsgbuflen = cmsg_space(sizeof(struct in6_pktinfo));
 #endif
 	sock->sendcmsgbuflen = cmsgbuflen;
-	sock->sendcmsgbufspace = cmsgbufspace;
 	if (sock->sendcmsgbuflen != 0U) {
-		sock->sendcmsgbuf = isc_mem_get(manager->mctx, cmsgbufspace);
+		sock->sendcmsgbuf = isc_mem_get(manager->mctx, cmsgbuflen);
 		if (sock->sendcmsgbuf == NULL)
 			goto error;
 	}
@@ -1360,10 +1348,10 @@ allocate_socket(isc_socketmgr_t *manager, isc_sockettype_t type,
  error:
 	if (sock->recvcmsgbuf != NULL)
 		isc_mem_put(manager->mctx, sock->recvcmsgbuf,
-			    sock->recvcmsgbufspace);
+			    sock->recvcmsgbuflen);
 	if (sock->sendcmsgbuf != NULL)
 		isc_mem_put(manager->mctx, sock->sendcmsgbuf,
-			    sock->sendcmsgbufspace);
+			    sock->sendcmsgbuflen);
 	isc_mem_put(manager->mctx, sock, sizeof(*sock));
 
 	return (result);
@@ -1393,10 +1381,10 @@ free_socket(isc_socket_t **socketp) {
 
 	if (sock->recvcmsgbuf != NULL)
 		isc_mem_put(sock->manager->mctx, sock->recvcmsgbuf,
-			    sock->recvcmsgbufspace);
+			    sock->recvcmsgbuflen);
 	if (sock->sendcmsgbuf != NULL)
 		isc_mem_put(sock->manager->mctx, sock->sendcmsgbuf,
-			    sock->sendcmsgbufspace);
+			    sock->sendcmsgbuflen);
 
 	sock->magic = 0;