[FFmpeg-cvslog] avcodec/cbs_h2645: Fix potential out-of-bounds array access

[Andreas Rheinhardt]

ffmpeg | branch: release/4.2 | Andreas Rheinhardt <andreas.rheinhardt at gmail.com> | Wed Sep 18 05:25:58 2019 +0200| [ca04589371f9240be31be6323dfec095492ea22e] | committer: Andreas Rheinhardt

avcodec/cbs_h2645: Fix potential out-of-bounds array access

The maximum allowed index for an array access is FF_ARRAY_ELEMS - 1; yet
the current code allowed FF_ARRAY_ELEMS. This wasn't dangerous in practice,
as parameter sets with invalid ids were already filtered out during
reading.

Found via PVS-Studio (see ticket #8156).

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at gmail.com>
(cherry picked from commit f3333c3c67e8825a4468120bb8aa0943c72c03f3)

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=ca04589371f9240be31be6323dfec095492ea22e
---

 libavcodec/cbs_h2645.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libavcodec/cbs_h2645.c b/libavcodec/cbs_h2645.c
index 2c66c0526c..f0a9448941 100644
--- a/libavcodec/cbs_h2645.c
+++ b/libavcodec/cbs_h2645.c
@@ -751,7 +751,7 @@ static int cbs_h26 ## h26n ## _replace_ ## ps_var(CodedBitstreamContext *ctx, \
     CodedBitstreamH26 ## h26n ## Context *priv = ctx->priv_data; \
     H26 ## h26n ## Raw ## ps_name *ps_var = unit->content; \
     unsigned int id = ps_var->id_element; \
-    if (id > FF_ARRAY_ELEMS(priv->ps_var)) { \
+    if (id >= FF_ARRAY_ELEMS(priv->ps_var)) { \
         av_log(ctx->log_ctx, AV_LOG_ERROR, "Invalid " #ps_name \
                " id : %d.\n", id); \
         return AVERROR_INVALIDDATA; \