On 2012-01-05 22:29:38 +0100, Kostya Shishkov wrote: > > I strongly suspect that this situation deserves an error message. > Additionally, it can be handled better: we should check read value to > be less that num_vectors > to make sure we always read correct vector.
done > Also I'd check num_vectors to be in range 0..256 on its init (line 804-805). done Janne ---8<--- Fixes null pointer dereferences in fuzzed files found by Oana Stratulat. Signed-off-by: Janne Grunau <[email protected]> --- libavcodec/indeo3.c | 22 ++++++++++++++++++---- 1 files changed, 18 insertions(+), 4 deletions(-) diff --git a/libavcodec/indeo3.c b/libavcodec/indeo3.c index 46efbd8..d2b01f4 100644 --- a/libavcodec/indeo3.c +++ b/libavcodec/indeo3.c @@ -89,6 +89,7 @@ typedef struct Indeo3DecodeContext { const uint8_t *next_cell_data; const uint8_t *last_byte; const int8_t *mc_vectors; + unsigned num_vectors; ///< number of motion vectors in mc_vectors int16_t width, height; uint32_t frame_num; ///< current frame number (zero-based) @@ -764,10 +765,16 @@ static int parse_bintree(Indeo3DecodeContext *ctx, AVCodecContext *avctx, break; case INTER_DATA: if (!curr_cell.tree) { /* MC tree INTER code */ + unsigned mv_idx; /* get motion vector index and setup the pointer to the mv set */ if (!ctx->need_resync) ctx->next_cell_data = &ctx->gb.buffer[(get_bits_count(&ctx->gb) + 7) >> 3]; - curr_cell.mv_ptr = &ctx->mc_vectors[*(ctx->next_cell_data++) << 1]; + mv_idx = *(ctx->next_cell_data++) << 1; + if (mv_idx >= ctx->num_vectors) { + av_log(avctx, AV_LOG_ERROR, "motion vector index out of range\n"); + return AVERROR_INVALIDDATA; + } + curr_cell.mv_ptr = &ctx->mc_vectors[mv_idx]; curr_cell.tree = 1; /* enter the VQ tree */ UPDATE_BITPOS(8); } else { /* VQ tree DATA code */ @@ -797,15 +804,22 @@ static int decode_plane(Indeo3DecodeContext *ctx, AVCodecContext *avctx, int32_t strip_width) { Cell curr_cell; - int num_vectors; + unsigned num_vectors; /* each plane data starts with mc_vector_count field, */ /* an optional array of motion vectors followed by the vq data */ num_vectors = bytestream_get_le32(&data); - ctx->mc_vectors = num_vectors ? data : 0; - + if (num_vectors > 256) { + av_log(ctx->avctx, AV_LOG_ERROR, + "Read invalid number of motion vectors %d\n", num_vectors); + return AVERROR_INVALIDDATA; + } if (num_vectors * 2 >= data_size) return AVERROR_INVALIDDATA; + + ctx->num_vectors = num_vectors; + ctx->mc_vectors = num_vectors ? data : 0; + /* init the bitreader */ init_get_bits(&ctx->gb, &data[num_vectors * 2], (data_size - num_vectors * 2) << 3); ctx->skip_bits = 0; -- 1.7.8.2 _______________________________________________ libav-devel mailing list [email protected] https://lists.libav.org/mailman/listinfo/libav-devel
