clockdiff, rdisc, ninfod: get rid of vla's

VLA's are slow and can lead to security issues, it is best to avoid these. Reference: https://lwn.net/Articles/763641/ Signed-off-by: Sami Kerola <[email protected]>
Mingli-Yu · Feb 3, 2019 · 6dd4bdc · 6dd4bdc
1 parent b6f2dab
commit 6dd4bdc
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Showing 3 changed files with 13 additions and 6 deletions.
diff --git a/clockdiff.c b/clockdiff.c
@@ -529,9 +529,11 @@ int main(int argc, char **argv)
 	if (ctl.ip_opt_len) {
 		struct sockaddr_in myaddr = { 0 };
 		socklen_t addrlen = sizeof(myaddr);
-		unsigned char rspace[ctl.ip_opt_len];
+		uint8_t *rspace;
 
-		memset(rspace, 0, sizeof(rspace));
+		if ((rspace = calloc(ctl.ip_opt_len, sizeof(uint8_t))) == NULL)
+			error(1, errno, "allocating %zu bytes failed",
+					ctl.ip_opt_len * sizeof(uint8_t));
 		rspace[0] = IPOPT_TIMESTAMP;
 		rspace[1] = ctl.ip_opt_len;
 		rspace[2] = 5;
@@ -550,6 +552,7 @@ int main(int argc, char **argv)
 			error(0, errno, "IP_OPTIONS (fallback to icmp tstamps)");
 			ctl.ip_opt_len = 0;
 		}
+		free(rspace);
 	}
 
 	measure_status = measure(&ctl);

diff --git a/ninfod/ni_ifaddrs.c b/ninfod/ni_ifaddrs.c
@@ -350,7 +350,7 @@ int ni_ifaddrs(struct ni_ifaddrs **ifap, sa_family_t family)
 #endif
 
 		if (build) {
-			data = calloc(1, NLMSG_ALIGN(sizeof(struct ni_ifaddrs[icnt]))
+			data = calloc(1, NLMSG_ALIGN(sizeof(struct ni_ifaddrs) * icnt)
 				      + dlen + xlen);
 			ifa = (struct ni_ifaddrs *) data;
 			if (ifap != NULL)

diff --git a/rdisc.c b/rdisc.c
@@ -1212,13 +1212,15 @@ join(int sock, struct sockaddr_in *sin)
 {
 	int i, j;
 	struct ip_mreqn mreq;
-	int joined[num_interfaces];
-
-	memset(joined, 0, sizeof(joined));
+	int *joined;
 
 	if (isbroadcast(sin))
 		return (0);
 
+	if ((joined = calloc(num_interfaces, sizeof(int))) == NULL) {
+		logperror("cannot allocate memory");
+		return (-1);
+	}
 	mreq.imr_multiaddr = sin->sin_addr;
 	for (i = 0; i < num_interfaces; i++) {
 		for (j = 0; j < i; j++) {
@@ -1234,11 +1236,13 @@ join(int sock, struct sockaddr_in *sin)
 		if (setsockopt(sock, IPPROTO_IP, IP_ADD_MEMBERSHIP,
 			       (char *)&mreq, sizeof(mreq)) < 0) {
 			logperror("setsockopt (IP_ADD_MEMBERSHIP)");
+			free(joined);
 			return (-1);
 		}
 
 		joined[i] = interfaces[i].ifindex;
 	}
+	free(joined);
 	return (0);
 }