avfilter: fix graphparser memleaks on error paths

Fixes CID700635, CID700636 and CID732274.

libavfilter/graphparser.c

@@ -238,10 +238,11 @@ static int link_filter_inouts(AVFilterContext *filt_ctx,
             return AVERROR(ENOMEM);
 
         if (p->filter_ctx) {
-            if ((ret = link_filter(p->filter_ctx, p->pad_idx, filt_ctx, pad, log_ctx)) < 0)
-                return ret;
+            ret = link_filter(p->filter_ctx, p->pad_idx, filt_ctx, pad, log_ctx);
             av_free(p->name);
             av_free(p);
+            if (ret < 0)
+                return ret;
         } else {
             p->filter_ctx = filt_ctx;
             p->pad_idx = pad;
@@ -289,8 +290,10 @@ static int parse_inputs(const char **buf, AVFilterInOut **curr_inputs,
             av_free(name);
         } else {
             /* Not in the list, so add it as an input */
-            if (!(match = av_mallocz(sizeof(AVFilterInOut))))
+            if (!(match = av_mallocz(sizeof(AVFilterInOut)))) {
+                av_free(name);
                 return AVERROR(ENOMEM);
+            }
             match->name    = name;
             match->pad_idx = pad;
         }
@@ -318,24 +321,27 @@ static int parse_outputs(const char **buf, AVFilterInOut **curr_inputs,
         AVFilterInOut *match;
 
         AVFilterInOut *input = *curr_inputs;
+
+        if (!name)
+            return AVERROR(EINVAL);
+
         if (!input) {
             av_log(log_ctx, AV_LOG_ERROR,
-                   "No output pad can be associated to link label '%s'.\n",
-                   name);
+                   "No output pad can be associated to link label '%s'.\n", name);
+            av_free(name);
             return AVERROR(EINVAL);
         }
         *curr_inputs = (*curr_inputs)->next;
 
-        if (!name)
-            return AVERROR(EINVAL);
-
         /* First check if the label is not in the open_inputs list */
         match = extract_inout(name, open_inputs);
 
         if (match) {
             if ((ret = link_filter(input->filter_ctx, input->pad_idx,
-                                   match->filter_ctx, match->pad_idx, log_ctx)) < 0)
+                                   match->filter_ctx, match->pad_idx, log_ctx)) < 0) {
+                av_free(name);
                 return ret;
+            }
             av_free(match->name);
             av_free(name);
             av_free(match);