Use the new defines that include the trailing '\0' in the code.

Replace occurences of the magic constant 2 with an offsetof macro
call that computes the size of the leading members of the sockaddr.
Use strlcpy instead of sprintf where appropriate. Document the new changes
in the man page.

4 files changed, 27 insertions, 21 deletions

diff --git a/lib/libnetgraph/internal.h b/lib/libnetgraph/internal.h
index 99b5ecc..0c947e5 100644
--- a/lib/libnetgraph/internal.h
+++ b/lib/libnetgraph/internal.h
@@ -46,6 +46,7 @@
 #include <sys/socket.h>
 #include <sys/select.h>
 #include <sys/linker.h>
+#include <stddef.h>
 
 #include <stdlib.h>
 #include <stdio.h>
@@ -55,6 +56,10 @@
 #include <ctype.h>
 #include <err.h>
 
+/* the 'sockaddr overhead' for a netgraph address. This is everything before
+ * the string that constitutes the address. */
+#define	NGSA_OVERHEAD	(offsetof(struct sockaddr_ng, sg_data))
+
 extern int	_gNgDebugLevel;
 
 extern void	(*_NgLog)(const char *fmt, ...);
diff --git a/lib/libnetgraph/msg.c b/lib/libnetgraph/msg.c
index 2c2565f..927a31a 100644
--- a/lib/libnetgraph/msg.c
+++ b/lib/libnetgraph/msg.c
@@ -76,7 +76,7 @@ NgSendMsg(int cs, const char *path,
 	msg.header.token = gMsgId;
 	msg.header.flags = NGF_ORIG;
 	msg.header.cmd = cmd;
-	snprintf(msg.header.cmdstr, NG_CMDSTRLEN + 1, "cmd%d", cmd);
+	snprintf(msg.header.cmdstr, NG_CMDSTRSIZ, "cmd%d", cmd);
 
 	/* Deliver message */
 	if (NgDeliverMsg(cs, path, &msg, args, arglen) < 0)
@@ -175,7 +175,7 @@ static int
 NgDeliverMsg(int cs, const char *path,
 	const struct ng_mesg *hdr, const void *args, size_t arglen)
 {
-	u_char sgbuf[NG_PATHLEN + 3];
+	u_char sgbuf[NG_PATHSIZ + NGSA_OVERHEAD];
 	struct sockaddr_ng *const sg = (struct sockaddr_ng *) sgbuf;
 	u_char *buf = NULL;
 	struct ng_mesg *msg;
@@ -203,8 +203,9 @@ NgDeliverMsg(int cs, const char *path,
 
 	/* Prepare socket address */
 	sg->sg_family = AF_NETGRAPH;
-	snprintf(sg->sg_data, NG_PATHLEN + 1, "%s", path);
-	sg->sg_len = strlen(sg->sg_data) + 3;
+	/* XXX handle overflow */
+	strlcpy(sg->sg_data, path, NG_PATHSIZ);
+	sg->sg_len = strlen(sg->sg_data) + 1 + NGSA_OVERHEAD;
 
 	/* Debugging */
 	if (_gNgDebugLevel >= 2) {
@@ -240,7 +241,7 @@ done:
 int
 NgRecvMsg(int cs, struct ng_mesg *rep, size_t replen, char *path)
 {
-	u_char sgbuf[NG_PATHLEN + sizeof(struct sockaddr_ng)];
+	u_char sgbuf[NG_PATHSIZ + NGSA_OVERHEAD];
 	struct sockaddr_ng *const sg = (struct sockaddr_ng *) sgbuf;
 	int len, sglen = sizeof(sgbuf);
 	int errnosv;
@@ -254,7 +255,7 @@ NgRecvMsg(int cs, struct ng_mesg *rep, size_t replen, char *path)
 		goto errout;
 	}
 	if (path != NULL)
-		snprintf(path, NG_PATHLEN + 1, "%s", sg->sg_data);
+		strlcpy(path, sg->sg_data, NG_PATHSIZ);
 
 	/* Debugging */
 	if (_gNgDebugLevel >= 2) {
diff --git a/lib/libnetgraph/netgraph.3 b/lib/libnetgraph/netgraph.3
index f847701..b50ccee 100644
--- a/lib/libnetgraph/netgraph.3
+++ b/lib/libnetgraph/netgraph.3
@@ -174,7 +174,7 @@ bytes.
 If
 .Fa "path"
 is non-NULL, it must point to a buffer of at least
-.Dv "NG_PATHLEN + 1"
+.Dv "NG_PATHSIZ"
 bytes, which will be filled in (and NUL terminated) with the path to
 the node from which the message was received.
 .Pp
@@ -216,7 +216,7 @@ and stores it in
 which must be large enough to hold the entire packet.  If
 .Fa "hook"
 is non-NULL, it must point to a buffer of at least
-.Dv "NG_HOOKLEN + 1"
+.Dv "NG_HOOKSIZ"
 bytes, which will be filled in (and NUL terminated) with the name of
 the hook on which the data was received.
 .Pp
diff --git a/lib/libnetgraph/sock.c b/lib/libnetgraph/sock.c
index d3bdf59..7485baa 100644
--- a/lib/libnetgraph/sock.c
+++ b/lib/libnetgraph/sock.c
@@ -60,7 +60,7 @@ __FBSDID("$FreeBSD$");
 int
 NgMkSockNode(const char *name, int *csp, int *dsp)
 {
-	char namebuf[NG_NODELEN + 1];
+	char namebuf[NG_NODESIZ];
 	int cs = -1;		/* control socket */
 	int ds = -1;		/* data socket */
 	int errnosv;
@@ -93,13 +93,13 @@ NgMkSockNode(const char *name, int *csp, int *dsp)
 gotNode:
 	/* Assign the node the desired name, if any */
 	if (name != NULL) {
-		u_char sbuf[NG_NODELEN + 3];
+		u_char sbuf[NG_NODESIZ + NGSA_OVERHEAD];
 		struct sockaddr_ng *const sg = (struct sockaddr_ng *) sbuf;
 
 		/* Assign name */
-		snprintf(sg->sg_data, NG_NODELEN + 1, "%s", name);
+		strlcpy(sg->sg_data, name, NG_NODESIZ);
 		sg->sg_family = AF_NETGRAPH;
-		sg->sg_len = strlen(sg->sg_data) + 3;
+		sg->sg_len = strlen(sg->sg_data) + 1 + NGSA_OVERHEAD;
 		if (bind(cs, (struct sockaddr *) sg, sg->sg_len) < 0) {
 			errnosv = errno;
 			if (_gNgDebugLevel >= 1)
@@ -108,7 +108,7 @@ gotNode:
 		}
 
 		/* Save node name */
-		snprintf(namebuf, sizeof(namebuf), "%s", name);
+		strlcpy(namebuf, name, sizeof(namebuf));
 	} else if (dsp != NULL) {
 		u_char rbuf[sizeof(struct ng_mesg) + sizeof(struct nodeinfo)];
 		struct ng_mesg *const resp = (struct ng_mesg *) rbuf;
@@ -135,7 +135,7 @@ gotNode:
 
 	/* Create data socket if desired */
 	if (dsp != NULL) {
-		u_char sbuf[NG_NODELEN + 4];
+		u_char sbuf[NG_NODESIZ + 1 + NGSA_OVERHEAD];
 		struct sockaddr_ng *const sg = (struct sockaddr_ng *) sbuf;
 
 		/* Create data socket, initially just "floating" */
@@ -147,9 +147,9 @@ gotNode:
 		}
 
 		/* Associate the data socket with the node */
-		snprintf(sg->sg_data, NG_NODELEN + 2, "%s:", namebuf);
+		snprintf(sg->sg_data, NG_NODESIZ + 1, "%s:", namebuf);
 		sg->sg_family = AF_NETGRAPH;
-		sg->sg_len = strlen(sg->sg_data) + 3;
+		sg->sg_len = strlen(sg->sg_data) + 1 + NGSA_OVERHEAD;
 		if (connect(ds, (struct sockaddr *) sg, sg->sg_len) < 0) {
 			errnosv = errno;
 			if (_gNgDebugLevel >= 1)
@@ -211,7 +211,7 @@ NgNameNode(int cs, const char *path, const char *fmt, ...)
 int
 NgRecvData(int ds, u_char * buf, size_t len, char *hook)
 {
-	u_char frombuf[NG_HOOKLEN + sizeof(struct sockaddr_ng)];
+	u_char frombuf[NG_HOOKSIZ + NGSA_OVERHEAD];
 	struct sockaddr_ng *const from = (struct sockaddr_ng *) frombuf;
 	int fromlen = sizeof(frombuf);
 	int rtn, errnosv;
@@ -228,7 +228,7 @@ NgRecvData(int ds, u_char * buf, size_t len, char *hook)
 
 	/* Copy hook name */
 	if (hook != NULL)
-		snprintf(hook, NG_HOOKLEN + 1, "%s", from->sg_data);
+		strlcpy(hook, from->sg_data, NG_HOOKSIZ);
 
 	/* Debugging */
 	if (_gNgDebugLevel >= 2) {
@@ -250,14 +250,14 @@ NgRecvData(int ds, u_char * buf, size_t len, char *hook)
 int
 NgSendData(int ds, const char *hook, const u_char * buf, size_t len)
 {
-	u_char sgbuf[NG_HOOKLEN + sizeof(struct sockaddr_ng)];
+	u_char sgbuf[NG_HOOKSIZ + NGSA_OVERHEAD];
 	struct sockaddr_ng *const sg = (struct sockaddr_ng *) sgbuf;
 	int errnosv;
 
 	/* Set up destination hook */
 	sg->sg_family = AF_NETGRAPH;
-	snprintf(sg->sg_data, NG_HOOKLEN + 1, "%s", hook);
-	sg->sg_len = strlen(sg->sg_data) + 3;
+	strlcpy(sg->sg_data, hook, NG_HOOKSIZ);
+	sg->sg_len = strlen(sg->sg_data) + 1 + NGSA_OVERHEAD;
 
 	/* Debugging */
 	if (_gNgDebugLevel >= 2) {