From 696ace50ea91a65dff887aaf5296f42a2fbc8f6c Mon Sep 17 00:00:00 2001 From: Janne Grunau Date: Thu, 5 Jan 2012 21:28:03 +0100 Subject: [PATCH] truemotion2: check size before GetBitContext initialisation Prevents null ptr derefence for negative sizes. --- libavcodec/truemotion2.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/libavcodec/truemotion2.c b/libavcodec/truemotion2.c index 8d72bb6df0..4045342ffa 100644 --- a/libavcodec/truemotion2.c +++ b/libavcodec/truemotion2.c @@ -272,6 +272,8 @@ static int tm2_read_stream(TM2Context *ctx, const uint8_t *buf, int stream_id, i len = AV_RB32(buf); buf += 4; cur += 4; } if(len > 0) { + if (skip <= cur) + return -1; init_get_bits(&ctx->gb, buf, (skip - cur) * 8); if(tm2_read_deltas(ctx, stream_id) == -1) return -1; @@ -286,6 +288,8 @@ static int tm2_read_stream(TM2Context *ctx, const uint8_t *buf, int stream_id, i buf += 4; cur += 4; buf += 4; cur += 4; /* unused by decoder */ + if (skip <= cur) + return -1; init_get_bits(&ctx->gb, buf, (skip - cur) * 8); if(tm2_build_huff_table(ctx, &codes) == -1) return -1; @@ -303,6 +307,8 @@ static int tm2_read_stream(TM2Context *ctx, const uint8_t *buf, int stream_id, i ctx->tok_lens[stream_id] = toks; len = AV_RB32(buf); buf += 4; cur += 4; if(len > 0) { + if (skip <= cur) + return -1; init_get_bits(&ctx->gb, buf, (skip - cur) * 8); for(i = 0; i < toks; i++) { if (get_bits_left(&ctx->gb) <= 0) {