From 7bed585c427cc5def85d68abedfc6bb382459d52 Mon Sep 17 00:00:00 2001
From: Jukka Rissanen <jukka.rissanen@linux.intel.com>
Date: Wed, 24 May 2017 13:41:02 +0300
Subject: [PATCH] net: zoap: Fix NULL pointer access

The code was setting pointer to null and then access it.

Coverity-CID: 157575

Signed-off-by: Jukka Rissanen <jukka.rissanen@linux.intel.com>
---
 subsys/net/lib/zoap/zoap_link_format.c | 54 ++++++++++++++++----------
 1 file changed, 33 insertions(+), 21 deletions(-)

diff --git a/subsys/net/lib/zoap/zoap_link_format.c b/subsys/net/lib/zoap/zoap_link_format.c
index 818cb34cb0e..2b9e176e3a1 100644
--- a/subsys/net/lib/zoap/zoap_link_format.c
+++ b/subsys/net/lib/zoap/zoap_link_format.c
@@ -28,7 +28,7 @@ static bool match_path_uri(const char * const *path,
 			   const char *uri, u16_t len)
 {
 	const char * const *p = NULL;
-	int i, j, plen;
+	int i, j, k, plen;
 
 	if (!path) {
 		return false;
@@ -46,31 +46,43 @@ static bool match_path_uri(const char * const *path,
 		return false;
 	}
 
+	/* Go through uri and try to find a matching path */
 	for (i = 1; i < len; i++) {
-		if (!*p) {
-			return false;
-		}
+		while (*p) {
+			plen = strlen(*p);
 
-		if (!p) {
+			k = i;
+
+			for (j = 0; j < plen; j++) {
+				if (uri[k] == '*') {
+					if ((k + 1) == len) {
+						return true;
+					}
+				}
+
+				if (uri[k] != (*p)[j]) {
+					goto next;
+				}
+
+				k++;
+			}
+
+			if (i == (k - 1) && j == plen) {
+				return true;
+			}
+
+			if (k == len && j == plen) {
+				return true;
+			}
+
+		next:
 			p++;
-			plen = *p ? strlen(*p) : 0;
-			j = 0;
 		}
+	}
 
-		if (j == plen && uri[i] == '/') {
-			p = NULL;
-			continue;
-		}
-
-		if (uri[i] == '*' && i + 1 == len) {
-			return true;
-		}
-
-		if (uri[i] != (*p)[j]) {
-			return false;
-		}
-
-		j++;
+	/* Did we find the resource or not */
+	if (i == len && !*p) {
+		return false;
 	}
 
 	return true;