Make sure substr is invoked with pos less than string length.

Change-Id: Ia9600fcc267051ca29a0e78c03af9b581f82a463
related-bug: 1536112
(cherry picked from commit 2fbce4c)
(cherry picked from commit 3206d5e)

src/http/http_session.cc

@@ -155,7 +155,6 @@ class HttpSession::RequestHandler : public Task {
     }
 
     void NotFound(HttpSession *session, const HttpRequest *request) {
-        string url = request->UrlPath().substr(1);
         static const char no_response[] =
 "HTTP/1.1 404 Not Found\r\n"
 "Content-Type: text/html; charset=UTF-8\r\n"

src/vnsw/agent/oper/vn.cc

@@ -201,12 +201,12 @@ bool VnEntry::GetPrefix(const Ip6Address &ip, Ip6Address *prefix,
 std::string VnEntry::GetProject() const {
     // TODO: update to get the project name from project-vn link.
     // Currently, this info doesnt come to the agent
-    std::size_t start_pos = name_.find(":") + 1;
-    std::size_t end_pos = name_.find(":", start_pos);
-    if (end_pos == std::string::npos)
+    std::string name(name_.c_str());
+    char *saveptr;
+    if (strtok_r(const_cast<char *>(name.c_str()), ":", &saveptr) == NULL)
         return "";
-
-    return name_.substr(start_pos, end_pos - start_pos);
+    char *project = strtok_r(NULL, ":", &saveptr);
+    return (project == NULL) ? "" : std::string(project);
 }
 
 int VnEntry::GetVxLanId() const {

src/vnsw/agent/services/metadata_proxy.cc

@@ -171,7 +171,9 @@ MetadataProxy::HandleMetadataRequest(HttpSession *session, const HttpRequest *re
     header_options.push_back(std::string("X-Instance-ID-Signature: " +
                                          signature));
 
-    std::string uri = request->UrlPath().substr(1); // ignore the first "/"
+    std::string uri = request->UrlPath();
+    if (uri.size())
+        uri = uri.substr(1); // ignore the first "/"
     const std::string &body = request->Body();
     {
         HttpConnection *conn = GetProxyConnection(session, conn_close);