[FFmpeg-cvslog] avfiltergraph: check for sws opts being non-NULL before using them.

[Anton Khirnov]

ffmpeg | branch: release/0.7 | Anton Khirnov <anton at khirnov.net> | Sun Mar 17 16:14:58 2013 +0100| [33c9e18b09f4025ae635ef24bab8eab1a686a711] | committer: Reinhard Tartler

avfiltergraph: check for sws opts being non-NULL before using them.

Avoid snprintfing a NULL pointer.

CC: libav-stable at libav.org
(cherry picked from commit 6e3c13a559e9ff300b5ca60e1d503e594d7f055c)

Signed-off-by: Reinhard Tartler <siretart at tauware.de>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=33c9e18b09f4025ae635ef24bab8eab1a686a711
---

 libavfilter/avfiltergraph.c |    7 ++++++-
 libavfilter/graphparser.c   |    3 ++-
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/libavfilter/avfiltergraph.c b/libavfilter/avfiltergraph.c
index af96807..b7dce75 100644
--- a/libavfilter/avfiltergraph.c
+++ b/libavfilter/avfiltergraph.c
@@ -23,6 +23,7 @@
 #include <ctype.h>
 #include <string.h>
 
+#include "libavutil/avstring.h"
 #include "avfilter.h"
 #include "avfiltergraph.h"
 #include "internal.h"
@@ -163,7 +164,11 @@ static int query_formats(AVFilterGraph *graph, AVClass *log_ctx)
                     /* couldn't merge format lists. auto-insert scale filter */
                     snprintf(inst_name, sizeof(inst_name), "auto-inserted scaler %d",
                              scaler_count++);
-                    snprintf(scale_args, sizeof(scale_args), "0:0:%s", graph->scale_sws_opts);
+                    av_strlcpy(scale_args, "0:0", sizeof(scale_args));
+                    if (graph->scale_sws_opts) {
+                        av_strlcat(scale_args, ":", sizeof(scale_args));
+                        av_strlcat(scale_args, graph->scale_sws_opts, sizeof(scale_args));
+                    }
                     if ((ret = avfilter_graph_create_filter(&scale, avfilter_get_by_name("scale"),
                                                             inst_name, scale_args, NULL, graph)) < 0)
                         return ret;
diff --git a/libavfilter/graphparser.c b/libavfilter/graphparser.c
index 00fb57a..0678cd0 100644
--- a/libavfilter/graphparser.c
+++ b/libavfilter/graphparser.c
@@ -121,7 +121,8 @@ static int create_filter(AVFilterContext **filt_ctx, AVFilterGraph *ctx, int ind
         return ret;
     }
 
-    if (!strcmp(filt_name, "scale") && args && !strstr(args, "flags")) {
+    if (!strcmp(filt_name, "scale") && args && !strstr(args, "flags") &&
+        ctx->scale_sws_opts) {
         snprintf(tmp_args, sizeof(tmp_args), "%s:%s",
                  args, ctx->scale_sws_opts);
         args = tmp_args;