diff options
author | Michael Niedermayer <michael@niedermayer.cc> | 2017-02-24 14:46:28 +0300 |
---|---|---|
committer | Michael Niedermayer <michael@niedermayer.cc> | 2017-02-24 16:12:12 +0300 |
commit | 8696f254444c2ec24daa570f26feadbd3df911e4 (patch) | |
tree | 7ea13a789f54ea67ce465e4c55007ffbdfe9c641 /libavcodec/rv34.c | |
parent | 178cd50c47aa5b7db03f7ce7a3f2934857dbd35b (diff) |
avcodec/rv34: Simplify and factor get_slice_offset() code
This also fixes several integer overflows by checking each value before
use.
Fixes: 662/clusterfuzz-testcase-4898131432964096
Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/targets/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
Diffstat (limited to 'libavcodec/rv34.c')
-rw-r--r-- | libavcodec/rv34.c | 42 |
1 files changed, 19 insertions, 23 deletions
diff --git a/libavcodec/rv34.c b/libavcodec/rv34.c index b5802d4ac3..be49804ebd 100644 --- a/libavcodec/rv34.c +++ b/libavcodec/rv34.c @@ -1591,10 +1591,13 @@ int ff_rv34_decode_update_thread_context(AVCodecContext *dst, const AVCodecConte return ff_mpeg_update_thread_context(dst, src); } -static int get_slice_offset(AVCodecContext *avctx, const uint8_t *buf, int n) +static int get_slice_offset(AVCodecContext *avctx, const uint8_t *buf, int n, int slice_count, int buf_size) { - if(avctx->slice_count) return avctx->slice_offset[n]; - else return AV_RL32(buf + n*8 - 4) == 1 ? AV_RL32(buf + n*8) : AV_RB32(buf + n*8); + if (n < slice_count) { + if(avctx->slice_count) return avctx->slice_offset[n]; + else return AV_RL32(buf + n*8 - 4) == 1 ? AV_RL32(buf + n*8) : AV_RB32(buf + n*8); + } else + return buf_size; } static int finish_frame(AVCodecContext *avctx, AVFrame *pict) @@ -1652,6 +1655,7 @@ int ff_rv34_decode_frame(AVCodecContext *avctx, const uint8_t *slices_hdr = NULL; int last = 0; int faulty_b = 0; + int offset; /* no supplementary picture */ if (buf_size == 0) { @@ -1674,13 +1678,13 @@ int ff_rv34_decode_frame(AVCodecContext *avctx, }else slice_count = avctx->slice_count; + offset = get_slice_offset(avctx, slices_hdr, 0, slice_count, buf_size); //parse first slice header to check whether this frame can be decoded - if(get_slice_offset(avctx, slices_hdr, 0) < 0 || - get_slice_offset(avctx, slices_hdr, 0) > buf_size){ + if(offset < 0 || offset > buf_size){ av_log(avctx, AV_LOG_ERROR, "Slice offset is invalid\n"); return AVERROR_INVALIDDATA; } - init_get_bits(&s->gb, buf+get_slice_offset(avctx, slices_hdr, 0), (buf_size-get_slice_offset(avctx, slices_hdr, 0))*8); + init_get_bits(&s->gb, buf+offset, (buf_size-offset)*8); if(r->parse_slice_header(r, &r->s.gb, &si) < 0 || si.start){ av_log(avctx, AV_LOG_ERROR, "First slice header is incorrect\n"); return AVERROR_INVALIDDATA; @@ -1783,40 +1787,32 @@ int ff_rv34_decode_frame(AVCodecContext *avctx, return AVERROR_INVALIDDATA; for(i = 0; i < slice_count; i++){ - int offset = get_slice_offset(avctx, slices_hdr, i); + int offset = get_slice_offset(avctx, slices_hdr, i , slice_count, buf_size); + int offset1 = get_slice_offset(avctx, slices_hdr, i+1, slice_count, buf_size); int size; - if(i+1 == slice_count) - size = buf_size - offset; - else - size = get_slice_offset(avctx, slices_hdr, i+1) - offset; - if(offset < 0 || offset > buf_size){ + if(offset < 0 || offset > offset1 || offset1 > buf_size){ av_log(avctx, AV_LOG_ERROR, "Slice offset is invalid\n"); break; } + size = offset1 - offset; r->si.end = s->mb_width * s->mb_height; s->mb_num_left = r->s.mb_x + r->s.mb_y*r->s.mb_width - r->si.start; if(i+1 < slice_count){ - if (get_slice_offset(avctx, slices_hdr, i+1) < 0 || - get_slice_offset(avctx, slices_hdr, i+1) > buf_size) { + int offset2 = get_slice_offset(avctx, slices_hdr, i+2, slice_count, buf_size); + if (offset2 < offset1 || offset2 > buf_size) { av_log(avctx, AV_LOG_ERROR, "Slice offset is invalid\n"); break; } - init_get_bits(&s->gb, buf+get_slice_offset(avctx, slices_hdr, i+1), (buf_size-get_slice_offset(avctx, slices_hdr, i+1))*8); + init_get_bits(&s->gb, buf+offset1, (buf_size-offset1)*8); if(r->parse_slice_header(r, &r->s.gb, &si) < 0){ - if(i+2 < slice_count) - size = get_slice_offset(avctx, slices_hdr, i+2) - offset; - else - size = buf_size - offset; + size = offset2 - offset; }else r->si.end = si.start; } - if (size < 0 || size > buf_size - offset) { - av_log(avctx, AV_LOG_ERROR, "Slice size is invalid\n"); - break; - } + av_assert0 (size >= 0 && size <= buf_size - offset); last = rv34_decode_slice(r, r->si.end, buf + offset, size); if(last) break; |