Add strict pattern matching on response when pattern was provided

Signed-off-by: Singh <[email protected]>

Author: sunjeets

ping.c

@@ -1103,6 +1103,8 @@ ping4_parse_reply(struct socket_st *sock, struct msghdr *msg, int cc, void *addr
 	if (icp->type == ICMP_ECHOREPLY) {
 		if (!is_ours(sock, icp->un.echo.id))
 			return 1;			/* 'Twas not our ECHO */
+		if (!contains_pattern_in_payload((__u8*)(icp+1)))
+			return 1;			/* 'Twas really not our ECHO */
 		if (gather_statistics((__u8*)icp, sizeof(*icp), cc,
 				      ntohs(icp->un.echo.sequence),
 				      ttl, 0, tv, pr_addr(from, sizeof *from),

ping.h

@@ -313,6 +313,7 @@ extern ping_func_set_st ping4_func_set;
 extern int pinger(ping_func_set_st *fset, socket_st *sock);
 extern void sock_setbufs(socket_st*, int alloc);
 extern void setup(socket_st *);
+extern int contains_pattern_in_payload(__u8 *ptr);
 extern void main_loop(ping_func_set_st *fset, socket_st*, __u8 *buf, int buflen) __attribute__((noreturn));
 extern void finish(void) __attribute__((noreturn));
 extern void status(void);

ping6_common.c

@@ -1420,6 +1420,8 @@ ping6_parse_reply(socket_st *sock, struct msghdr *msg, int cc, void *addr, struc
 	if (icmph->icmp6_type == ICMP6_ECHO_REPLY) {
 		if (!is_ours(sock, icmph->icmp6_id))
 			return 1;
+               if (!contains_pattern_in_payload((__u8*)(icmph+1)))
+               		return 1;            /* 'Twas really not our ECHO */
 		if (gather_statistics((__u8*)icmph, sizeof(*icmph), cc,
 				      ntohs(icmph->icmp6_seq),
 				      hops, 0, tv, pr_addr(from, sizeof *from),

ping_common.c

@@ -565,6 +565,24 @@ void setup(socket_st *sock)
 	}
 }
 
+/*
+ * Return 0 if pattern in payload point to be ptr did not match the pattern that was sent  
+ */
+int contains_pattern_in_payload(__u8 *ptr)
+{
+	int i;
+	__u8 *cp, *dp;
+ 
+	/* check the data */
+	cp = ((u_char*)ptr) + sizeof(struct timeval);
+	dp = &outpack[8 + sizeof(struct timeval)];
+	for (i = sizeof(struct timeval); i < datalen; ++i, ++cp, ++dp) {
+		if (*cp != *dp)
+			return 0;
+	}
+	return 1;
+}
+
 void main_loop(ping_func_set_st *fset, socket_st *sock, __u8 *packet, int packlen)
 {
 	char addrbuf[128];