From 60201e27efa6bf98f9dbdf6ea18c3c91183f937f Mon Sep 17 00:00:00 2001 From: Andreas Cadhalpun Date: Tue, 28 Apr 2015 11:13:43 +0200 Subject: apedec: prevent out of array writes in decode_array_0000 s->decoded_buffer is allocated with a min_size of: 2 * FFALIGN(blockstodecode, 8) * sizeof(*s->decoded_buffer) Then it is assigned to s->decoded[0] (and s->decoded_buffer + FFALIGN(blockstodecode, 8) to s->decoded[1]) and passed as out buffer to decode_array_0000. In this function 64 elements of the out buffer are written unconditionally and outside the array if blockstodecode is too small. This causes memory corruption, leading to segmentation faults or other crashes. Thus change decode_array_0000 to write at most blockstodecode elements of the out buffer. Signed-off-by: Andreas Cadhalpun Signed-off-by: Michael Niedermayer (cherry picked from commit 699341d647f7af785fb8ceed67604467b0b9ab12) Signed-off-by: Michael Niedermayer --- libavcodec/apedec.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/libavcodec/apedec.c b/libavcodec/apedec.c index f6de304006..e1e7da7a39 100644 --- a/libavcodec/apedec.c +++ b/libavcodec/apedec.c @@ -598,14 +598,14 @@ static void decode_array_0000(APEContext *ctx, GetBitContext *gb, int ksummax, ksummin; rice->ksum = 0; - for (i = 0; i < 5; i++) { + for (i = 0; i < FFMIN(blockstodecode, 5); i++) { out[i] = get_rice_ook(&ctx->gb, 10); rice->ksum += out[i]; } rice->k = av_log2(rice->ksum / 10) + 1; if (rice->k >= 24) return; - for (; i < 64; i++) { + for (; i < FFMIN(blockstodecode, 64); i++) { out[i] = get_rice_ook(&ctx->gb, rice->k); rice->ksum += out[i]; rice->k = av_log2(rice->ksum / ((i + 1) * 2)) + 1; -- cgit v1.2.1