avcodec/decode: Fix leaks upon subtitle decoding errors

Up until now, various subtitle decoders have not cleaned up
the AVSubtitle on error; this task must not be left to the user
because the documentation explicitly states that the AVSubtitle
"must be freed with avsubtitle_free if *got_sub_ptr is set"
(which it isn't on error).
Leaks happen upon failure in ff_ass_add_rect() or in
ass_decode_frame(); freeing generically also allows to remove
now redundant freeing code in pgssubdec and dvbsubdec.
While just at it, also reset got_sub_ptr generically on error.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>

1 files changed, 1 insertions, 4 deletions

diff --git a/libavcodec/pgssubdec.c b/libavcodec/pgssubdec.c
index 8a200aa01b..bdd20c914b 100644
--- a/libavcodec/pgssubdec.c
+++ b/libavcodec/pgssubdec.c
@@ -667,11 +667,8 @@ static int decode(AVCodecContext *avctx, void *data, int *got_sub_ptr,
             break;
         }
         if (ret < 0 && (ret == AVERROR(ENOMEM) ||
-                        avctx->err_recognition & AV_EF_EXPLODE)) {
-            avsubtitle_free(data);
-            *got_sub_ptr = 0;
+                        avctx->err_recognition & AV_EF_EXPLODE))
             return ret;
-        }
 
         buf += segment_length;
     }