[FFmpeg-devel] [PATCH 03/10] avcodec/cbs_av1: Fix potential undefined shift

[Andreas Rheinhardt]

1 << w is undefined as soon as w is >= 31, as 1 has type int. In the
case of cbs_av1_read_ns, w could potentially even be 32, so one has to
use a 64bit type.

(None of the current callers ever use arguments that are so large that
the above scenario can happen, but this might change in the future.)

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at gmail.com>
---
 libavcodec/cbs_av1.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libavcodec/cbs_av1.c b/libavcodec/cbs_av1.c
index 98cd37ef74..0ff6d60ae2 100644
--- a/libavcodec/cbs_av1.c
+++ b/libavcodec/cbs_av1.c
@@ -220,7 +220,7 @@ static int cbs_av1_read_ns(CodedBitstreamContext *ctx, GetBitContext *gbc,
         position = get_bits_count(gbc);
 
     w = av_log2(n) + 1;
-    m = (1 << w) - n;
+    m = (1LL << w) - n;
 
     if (get_bits_left(gbc) < w) {
         av_log(ctx->log_ctx, AV_LOG_ERROR, "Invalid non-symmetric value at "
-- 
2.20.1