From 128b42f4d1910ff4a2f1bbf8c7e401c5f246e4dc Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Fri, 12 May 2017 04:12:15 +0200 Subject: [PATCH] avcodec/aacsbr_template: Do not change bs_num_env before its checked Fixes: 1489/clusterfuzz-testcase-minimized-5075102901207040 Fixes: out of array access Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/targets/ffmpeg Signed-off-by: Michael Niedermayer (cherry picked from commit 87b08ee6d2a3b0880f0a267c5d51dc7f415e81d7) Signed-off-by: Michael Niedermayer --- libavcodec/aacsbr_template.c | 28 +++++++++++++++------------- 1 file changed, 15 insertions(+), 13 deletions(-) diff --git a/libavcodec/aacsbr_template.c b/libavcodec/aacsbr_template.c index aaa48ef802..930d33e9e5 100644 --- a/libavcodec/aacsbr_template.c +++ b/libavcodec/aacsbr_template.c @@ -624,25 +624,26 @@ static int read_sbr_grid(AACContext *ac, SpectralBandReplication *sbr, int abs_bord_trail = 16; int num_rel_lead, num_rel_trail; unsigned bs_num_env_old = ch_data->bs_num_env; + int bs_frame_class, bs_num_env; ch_data->bs_freq_res[0] = ch_data->bs_freq_res[ch_data->bs_num_env]; ch_data->bs_amp_res = sbr->bs_amp_res_header; ch_data->t_env_num_env_old = ch_data->t_env[bs_num_env_old]; - switch (ch_data->bs_frame_class = get_bits(gb, 2)) { + switch (bs_frame_class = get_bits(gb, 2)) { case FIXFIX: - ch_data->bs_num_env = 1 << get_bits(gb, 2); + bs_num_env = 1 << get_bits(gb, 2); + if (bs_num_env > 4) { + av_log(ac->avctx, AV_LOG_ERROR, + "Invalid bitstream, too many SBR envelopes in FIXFIX type SBR frame: %d\n", + bs_num_env); + return -1; + } + ch_data->bs_num_env = bs_num_env; num_rel_lead = ch_data->bs_num_env - 1; if (ch_data->bs_num_env == 1) ch_data->bs_amp_res = 0; - if (ch_data->bs_num_env > 4) { - av_log(ac->avctx, AV_LOG_ERROR, - "Invalid bitstream, too many SBR envelopes in FIXFIX type SBR frame: %d\n", - ch_data->bs_num_env); - ch_data->bs_num_env = 2; - return -1; - } ch_data->t_env[0] = 0; ch_data->t_env[ch_data->bs_num_env] = abs_bord_trail; @@ -690,15 +691,15 @@ static int read_sbr_grid(AACContext *ac, SpectralBandReplication *sbr, abs_bord_trail += get_bits(gb, 2); num_rel_lead = get_bits(gb, 2); num_rel_trail = get_bits(gb, 2); - ch_data->bs_num_env = num_rel_lead + num_rel_trail + 1; + bs_num_env = num_rel_lead + num_rel_trail + 1; - if (ch_data->bs_num_env > 5) { + if (bs_num_env > 5) { av_log(ac->avctx, AV_LOG_ERROR, "Invalid bitstream, too many SBR envelopes in VARVAR type SBR frame: %d\n", - ch_data->bs_num_env); - ch_data->bs_num_env = 2; + bs_num_env); return -1; } + ch_data->bs_num_env = bs_num_env; ch_data->t_env[ch_data->bs_num_env] = abs_bord_trail; @@ -713,6 +714,7 @@ static int read_sbr_grid(AACContext *ac, SpectralBandReplication *sbr, get_bits1_vector(gb, ch_data->bs_freq_res + 1, ch_data->bs_num_env); break; } + ch_data->bs_frame_class = bs_frame_class; av_assert0(bs_pointer >= 0); if (bs_pointer > ch_data->bs_num_env + 1) {