[FFmpeg-devel] [PATCH] lavfi/af_pan: fix sscanf return value check

[Nicolas George]

sscanf() can return -1 when it reach the end of the string.

Fix track ticket #10677.

Signed-off-by: Nicolas George <george at nsup.org>
---
 libavfilter/af_pan.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/libavfilter/af_pan.c b/libavfilter/af_pan.c
index cfed9f146a..9ab827b396 100644
--- a/libavfilter/af_pan.c
+++ b/libavfilter/af_pan.c
@@ -69,7 +69,7 @@ static int parse_channel_name(char **arg, int *rchannel, int *rnamed)
 
     skip_spaces(arg);
     /* try to parse a channel name, e.g. "FL" */
-    if (sscanf(*arg, "%7[A-Z]%n", buf, &len)) {
+    if (sscanf(*arg, "%7[A-Z]%n", buf, &len) >= 1) {
         channel_id = av_channel_from_string(buf);
         if (channel_id < 0)
             return channel_id;
@@ -80,7 +80,7 @@ static int parse_channel_name(char **arg, int *rchannel, int *rnamed)
         return 0;
     }
     /* try to parse a channel number, e.g. "c2" */
-    if (sscanf(*arg, "c%d%n", &channel_id, &len) &&
+    if (sscanf(*arg, "c%d%n", &channel_id, &len) >= 1 &&
         channel_id >= 0 && channel_id < MAX_CHANNELS) {
         *rchannel = channel_id;
         *rnamed = 0;
@@ -165,7 +165,7 @@ static av_cold int init(AVFilterContext *ctx)
         sign = 1;
         while (1) {
             gain = 1;
-            if (sscanf(arg, "%lf%n *%n", &gain, &len, &len))
+            if (sscanf(arg, "%lf%n *%n", &gain, &len, &len) >= 1)
                 arg += len;
             if (parse_channel_name(&arg, &in_ch_id, &named)){
                 av_log(ctx, AV_LOG_ERROR,
-- 
2.42.0