[patch] This is my proposed patch. It has the exact same functionality as the current one, but it does not leak.

net-snmp-5.4.1-clientaddr-fix.doug.patch (text/plain), 2.50 KB, created by Doug on 2007-11-20 18:00:22 UTC

--- snmplib/snmpUDPDomain.c.original	2007-11-20 16:43:55.000000000 +0000
+++ snmplib/snmpUDPDomain.c	2007-11-20 17:43:29.000000000 +0000
@@ -103,12 +103,26 @@
         struct sockaddr_in *to = NULL;
 	char tmp[64];
         to = (struct sockaddr_in *) &(addr_pair->remote_addr);
+        /* Using strdup on the output of inet_ntoa is important! */
+        /* "inet_ntoa" uses a statically allocated buffer to store
+           its information.  To use two in a row, the first needs
+           to be saved somewhere else so that the second does not
+           overwrite it.  However, it is important to remember that
+           all "strdup" calls MUST be freed. */
         if (to == NULL) {
-            return strdup("UDP: unknown");
+            sprintf(tmp, "UDP: [%s]->unknown",
+                    inet_ntoa(addr_pair->local_addr));
+        } else {
+            /* This will store the first address from strdup so that the second
+               call will not overwrite it. */
+            char* local_addr_copy = strdup( inet_ntoa(addr_pair->local_addr) );
+            sprintf(tmp, "UDP: [%s]->[%s]:%hu",
+                    local_addr_copy,
+                    inet_ntoa(to->sin_addr), ntohs(to->sin_port));
+            /* Remember, we must free our copy now. */
+            free( local_addr_copy );
         }
 
-        sprintf(tmp, "UDP: [%s]:%hu",
-                inet_ntoa(to->sin_addr), ntohs(to->sin_port));
         return strdup(tmp);
     }
 }
@@ -666,11 +680,23 @@
                                               NETSNMP_DS_LIB_CLIENT_ADDR);
         if (client_socket) {
             struct sockaddr_in client_addr;
+            int ret;
             netsnmp_sockaddr_in2(&client_addr, client_socket, NULL);
+            addr_pair.local_addr = client_addr.sin_addr;
             client_addr.sin_port = 0;
-            bind(t->sock, (struct sockaddr *)&client_addr,
+            ret = bind(t->sock, (struct sockaddr *)&client_addr,
                   sizeof(struct sockaddr));
+            if(ret)
+                DEBUGMSGTL(("netsnmp_udp", "failed to bind for clientaddr: %d %s\n",
+                            errno,strerror(errno)));
+            /* TODO: should we exit here? */
         }
+
+        str = netsnmp_udp_fmtaddr(NULL, (void *)&addr_pair, 
+                sizeof(netsnmp_udp_addr_pair));
+        DEBUGMSGTL(("netsnmp_udp", "client open %s\n", str));
+        free(str);
+
         /*
          * Save the (remote) address in the
          * transport-specific data pointer for later use by netsnmp_udp_send.