[FFmpeg-cvslog] avcodec/wavpack: fix regression in decoding

[Paul B Mahol]

ffmpeg | branch: master | Paul B Mahol <onemda at gmail.com> | Tue Aug 23 22:39:41 2022 +0200| [9bf9d42d013bb6ff17aca90d63e2e257a50a6dc3] | committer: Paul B Mahol

avcodec/wavpack: fix regression in decoding

Regression introduced in c6831e2a70f734c71f483d69d46d0635963530.
Fix it by using bitreader that reads 0-32 bits, instead of
0-25 bits and asserting on anything higher.

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=9bf9d42d013bb6ff17aca90d63e2e257a50a6dc3
---

 libavcodec/wavpack.c | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/libavcodec/wavpack.c b/libavcodec/wavpack.c
index c12e1d6ec6..a09ce00fe2 100644
--- a/libavcodec/wavpack.c
+++ b/libavcodec/wavpack.c
@@ -119,7 +119,7 @@ typedef struct WavpackContext {
 
 #define LEVEL_DECAY(a)  (((a) + 0x80) >> 8)
 
-static av_always_inline unsigned get_tail(GetBitContext *gb, int k)
+static av_always_inline unsigned get_tail(GetBitContext *gb, unsigned k)
 {
     int p, e, res;
 
@@ -127,7 +127,7 @@ static av_always_inline unsigned get_tail(GetBitContext *gb, int k)
         return 0;
     p   = av_log2(k);
     e   = (1 << (p + 1)) - k - 1;
-    res = get_bitsz(gb, p);
+    res = get_bits_long(gb, p);
     if (res >= e)
         res = (res << 1) - e + get_bits1(gb);
     return res;
@@ -266,10 +266,6 @@ static int wv_get_value(WavpackFrameContext *ctx, GetBitContext *gb,
         INC_MED(2);
     }
     if (!c->error_limit) {
-        if (add >= 0x2000000U) {
-            av_log(ctx->avctx, AV_LOG_ERROR, "k %d is too large\n", add);
-            goto error;
-        }
         ret = base + get_tail(gb, add);
         if (get_bits_left(gb) <= 0)
             goto error;