From 9fb80f7170ec48e23c3c7b477149eeb37081c699 Mon Sep 17 00:00:00 2001 From: John Koleszar Date: Thu, 4 Nov 2010 16:59:26 -0400 Subject: [PATCH] fix integer promotion bug in partition size check The check '(user_data_end - partition < partition_size)' must be evaluated as a signed comparison, but because partition_size was unsigned, the LHS was promoted to unsigned, causing an incorrect result on 32-bit. Instead, check the upper and lower bounds of the segment separately. Change-Id: I6266aba7fd7de084268712a3d2a81424ead7aa06 --- vp8/decoder/decodframe.c | 6 ++++-- vp8/vp8_dx_iface.c | 10 ++++++++-- 2 files changed, 12 insertions(+), 4 deletions(-) diff --git a/vp8/decoder/decodframe.c b/vp8/decoder/decodframe.c index 2d81d61..f5e49a1 100644 --- a/vp8/decoder/decodframe.c +++ b/vp8/decoder/decodframe.c @@ -462,7 +462,8 @@ static void setup_token_decoder(VP8D_COMP *pbi, partition_size = user_data_end - partition; } - if (user_data_end - partition < partition_size) + if (partition + partition_size > user_data_end + || partition + partition_size < partition) vpx_internal_error(&pc->error, VPX_CODEC_CORRUPT_FRAME, "Truncated packet or corrupt partition " "%d length", i + 1); @@ -580,7 +581,8 @@ int vp8_decode_frame(VP8D_COMP *pbi) (data[0] | (data[1] << 8) | (data[2] << 16)) >> 5; data += 3; - if (data_end - data < first_partition_length_in_bytes) + if (data + first_partition_length_in_bytes > data_end + || data + first_partition_length_in_bytes < data) vpx_internal_error(&pc->error, VPX_CODEC_CORRUPT_FRAME, "Truncated packet or corrupt partition 0 length"); vp8_setup_version(pc); diff --git a/vp8/vp8_dx_iface.c b/vp8/vp8_dx_iface.c index e7e5356..f0adf5b 100644 --- a/vp8/vp8_dx_iface.c +++ b/vp8/vp8_dx_iface.c @@ -253,8 +253,11 @@ static vpx_codec_err_t vp8_peek_si(const uint8_t *data, unsigned int data_sz, vpx_codec_stream_info_t *si) { - vpx_codec_err_t res = VPX_CODEC_OK; + + if(data + data_sz <= data) + res = VPX_CODEC_INVALID_PARAM; + else { /* Parse uncompresssed part of key frame header. * 3 bytes:- including version, frame type and an offset @@ -331,7 +334,10 @@ static vpx_codec_err_t vp8_decode(vpx_codec_alg_priv_t *ctx, ctx->img_avail = 0; - /* Determine the stream parameters */ + /* Determine the stream parameters. Note that we rely on peek_si to + * validate that we have a buffer that does not wrap around the top + * of the heap. + */ if (!ctx->si.h) res = ctx->base.iface->dec.peek_si(data, data_sz, &ctx->si); -- 1.7.3.1