Fix null pointer dereference in pmproxy

src/libpcp_web/src/batons.c

@@ -128,13 +128,25 @@ seriesPassBaton(seriesBatonPhase **head, void *arg, const char *caller)
     seriesBatonPhase	*next;
     seriesBatonMagic	*baton = (seriesBatonMagic *)arg;
 
+    if (baton == NULL) {
+        pmNotifyErr(LOG_ERR, "%s: NULL baton from %s\n", __FUNCTION__, caller);
+        return;
+    }
+    if (head == NULL) {
+        pmNotifyErr(LOG_ERR, "%s: NULL baton from %s\n", __FUNCTION__, caller);
+        return;
+    }
+
     if (UNLIKELY(baton->traced || pmDebugOptions.series)) {
 	fprintf(stderr,
 		"Baton [%s/%p] references: %u -> %u (@ %s[%s])\n",
 		magic_str(baton), baton, baton->refcount, baton->refcount - 1,
 		caller, "seriesPassBaton");
     }
-    assert(baton->refcount);
+    if (baton->refcount == 0) {
+        pmNotifyErr(LOG_ERR, "%s: refcount is 0 from %s\n", __FUNCTION__, caller);
+        return;
+    }
 
     if (--baton->refcount > 0) {
 	/* phase still in-progress so no more to do */

src/libpcp_web/src/discover.c

@@ -123,6 +123,13 @@ pmDiscoverLookupAdd(const char *fullpath, pmDiscoverModule *module, void *arg)
 	h->context.name = name;
 	h->metavol = sdsempty();
 	h->datavol = sdsempty();
+	if (h->metavol == NULL || h->datavol == NULL) {
+	    sdsfree(h->metavol);
+	    sdsfree(h->datavol);
+	    sdsfree(name);
+	    free(h);
+	    return NULL;
+	}
 	h->module = module;
 	h->data = arg;
 	if (p == NULL)
@@ -297,6 +304,12 @@ pmDiscoverArchives(const char *dir, pmDiscoverModule *module, void *arg)
      * if this is a newly discovered archive or directory
      */
     a = pmDiscoverLookupAdd(dir, module, arg);
+    if (a == NULL) {
+	if (pmDebugOptions.discovery)
+	    fprintf(stderr, "%s: pmDiscoverLookupAdd failed for %s\n",
+			    __FUNCTION__, dir);
+	return -ENOMEM;
+    }
     a->flags |= DISCOVER_FLAGS_DIRECTORY;
 
     if ((dirp = opendir(dir)) == NULL) {
@@ -332,6 +345,12 @@ pmDiscoverArchives(const char *dir, pmDiscoverModule *module, void *arg)
 		 */
 		*suffix = '\0'; /* strip suffix from path giving archive name */
 		a = pmDiscoverLookupAdd(path, module, arg);
+		if (a == NULL) {
+		    if (pmDebugOptions.discovery)
+			fprintf(stderr, "%s: pmDiscoverLookupAdd failed for %s\n",
+					__FUNCTION__, path);
+		    continue;
+		}
 
 		/*
 		 * note: pmDiscoverLookupAdd sets DISCOVER_FLAGS_NEW

src/libpcp_web/src/load.c

@@ -1164,6 +1164,10 @@ freeSeriesLoadBaton(seriesLoadBaton *baton)
 void
 doneSeriesLoadBaton(seriesLoadBaton *baton, const char *caller)
 {
+    if (baton == NULL) {
+        pmNotifyErr(LOG_ERR, "%s: NULL baton from %s\n", __FUNCTION__, caller);
+        return;
+    }
     seriesPassBaton(&baton->current, baton, caller);
 }
 
@@ -1310,7 +1314,7 @@ void
 pmSeriesDiscoverClosed(pmDiscoverEvent *event, void *arg)
 {
     pmDiscover		*p = (pmDiscover *)event->data;
-    seriesLoadBaton	*baton = p->baton;
+    seriesLoadBaton	*baton = p ? p->baton : NULL; 
 
     (void)arg;