From eb41956636fc264fe2077b78ef00591d83bbbace Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Thu, 2 Mar 2017 03:02:07 +0100 Subject: [PATCH] avcodec/mpeg4videodec: Improve the overflow checks in mpeg4_decode_sprite_trajectory() Also clear the state on errors Fixes integer overflows in 701/clusterfuzz-testcase-6594719951880192 Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/targets/ffmpeg Signed-off-by: Michael Niedermayer --- libavcodec/mpeg4videodec.c | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-) diff --git a/libavcodec/mpeg4videodec.c b/libavcodec/mpeg4videodec.c index 9f9374d550..568263ecdf 100644 --- a/libavcodec/mpeg4videodec.c +++ b/libavcodec/mpeg4videodec.c @@ -375,7 +375,7 @@ static int mpeg4_decode_sprite_trajectory(Mpeg4DecContext *ctx, GetBitContext *g FFABS(s->sprite_offset[1][1]) >= INT_MAX >> shift_c ) { avpriv_request_sample(s->avctx, "Too large sprite shift or offset"); - return AVERROR_PATCHWELCOME; + goto overflow; } for (i = 0; i < 2; i++) { @@ -385,17 +385,23 @@ static int mpeg4_decode_sprite_trajectory(Mpeg4DecContext *ctx, GetBitContext *g s->sprite_delta[1][i] *= 1 << shift_y; ctx->sprite_shift[i] = 16; - if (llabs(s->sprite_offset[i][0] + s->sprite_delta[i][0] * (int64_t)w) >= INT_MAX || - llabs(s->sprite_offset[i][0] + s->sprite_delta[i][1] * (int64_t)h) >= INT_MAX || - llabs(s->sprite_offset[i][0] + s->sprite_delta[i][0] * (int64_t)w + s->sprite_delta[i][1] * (int64_t)h) >= INT_MAX) { + } + for (i = 0; i < 2; i++) { + if (llabs(s->sprite_offset[0][i] + s->sprite_delta[i][0] * (w+16LL)) >= INT_MAX || + llabs(s->sprite_offset[0][i] + s->sprite_delta[i][1] * (h+16LL)) >= INT_MAX || + llabs(s->sprite_offset[0][i] + s->sprite_delta[i][0] * (w+16LL) + s->sprite_delta[i][1] * (h+16LL)) >= INT_MAX) { avpriv_request_sample(s->avctx, "Overflow on sprite points"); - return AVERROR_PATCHWELCOME; + goto overflow; } } s->real_sprite_warping_points = ctx->num_sprite_warping_points; } return 0; +overflow: + memset(s->sprite_offset, 0, sizeof(s->sprite_offset)); + memset(s->sprite_delta, 0, sizeof(s->sprite_delta)); + return AVERROR_PATCHWELCOME; } static int decode_new_pred(Mpeg4DecContext *ctx, GetBitContext *gb) {