From 64263dd526ec25ede1591fc1144715a20cc7bc4e Mon Sep 17 00:00:00 2001 From: Laurent Aimar Date: Thu, 29 Sep 2011 23:13:35 +0000 Subject: tiertexseqv: Check for out of bound reads Signed-off-by: Janne Grunau --- libavcodec/tiertexseqv.c | 65 +++++++++++++++++++++++++++++++++++++----------- 1 file changed, 51 insertions(+), 14 deletions(-) (limited to 'libavcodec/tiertexseqv.c') diff --git a/libavcodec/tiertexseqv.c b/libavcodec/tiertexseqv.c index cdb342a30c..d48fa15a72 100644 --- a/libavcodec/tiertexseqv.c +++ b/libavcodec/tiertexseqv.c @@ -35,15 +35,19 @@ typedef struct SeqVideoContext { } SeqVideoContext; -static const unsigned char *seq_unpack_rle_block(const unsigned char *src, unsigned char *dst, int dst_size) +static const unsigned char *seq_unpack_rle_block(const unsigned char *src, + const unsigned char *src_end, + unsigned char *dst, int dst_size) { int i, len, sz; GetBitContext gb; int code_table[64]; - /* get the rle codes (at most 64 bytes) */ - init_get_bits(&gb, src, 64 * 8); + /* get the rle codes */ + init_get_bits(&gb, src, (src_end - src) * 8); for (i = 0, sz = 0; i < 64 && sz < dst_size; i++) { + if (get_bits_left(&gb) < 4) + return NULL; code_table[i] = get_sbits(&gb, 4); sz += FFABS(code_table[i]); } @@ -54,8 +58,12 @@ static const unsigned char *seq_unpack_rle_block(const unsigned char *src, unsig len = code_table[i]; if (len < 0) { len = -len; + if (src_end - src < 1) + return NULL; memset(dst, *src++, FFMIN(len, dst_size)); } else { + if (src_end - src < len) + return NULL; memcpy(dst, src, FFMIN(len, dst_size)); src += len; } @@ -65,25 +73,30 @@ static const unsigned char *seq_unpack_rle_block(const unsigned char *src, unsig return src; } -static const unsigned char *seq_decode_op1(SeqVideoContext *seq, const unsigned char *src, unsigned char *dst) +static const unsigned char *seq_decode_op1(SeqVideoContext *seq, + const unsigned char *src, + const unsigned char *src_end, + unsigned char *dst) { const unsigned char *color_table; int b, i, len, bits; GetBitContext gb; unsigned char block[8 * 8]; + if (src_end - src < 1) + return NULL; len = *src++; if (len & 0x80) { switch (len & 3) { case 1: - src = seq_unpack_rle_block(src, block, sizeof(block)); + src = seq_unpack_rle_block(src, src_end, block, sizeof(block)); for (b = 0; b < 8; b++) { memcpy(dst, &block[b * 8], 8); dst += seq->frame.linesize[0]; } break; case 2: - src = seq_unpack_rle_block(src, block, sizeof(block)); + src = seq_unpack_rle_block(src, src_end, block, sizeof(block)); for (i = 0; i < 8; i++) { for (b = 0; b < 8; b++) dst[b * seq->frame.linesize[0]] = block[i * 8 + b]; @@ -92,9 +105,13 @@ static const unsigned char *seq_decode_op1(SeqVideoContext *seq, const unsigned break; } } else { + if (len <= 0) + return NULL; + bits = ff_log2_tab[len - 1] + 1; + if (src_end - src < len + 8 * bits) + return NULL; color_table = src; src += len; - bits = ff_log2_tab[len - 1] + 1; init_get_bits(&gb, src, bits * 8 * 8); src += bits * 8; for (b = 0; b < 8; b++) { for (i = 0; i < 8; i++) @@ -106,10 +123,16 @@ static const unsigned char *seq_decode_op1(SeqVideoContext *seq, const unsigned return src; } -static const unsigned char *seq_decode_op2(SeqVideoContext *seq, const unsigned char *src, unsigned char *dst) +static const unsigned char *seq_decode_op2(SeqVideoContext *seq, + const unsigned char *src, + const unsigned char *src_end, + unsigned char *dst) { int i; + if (src_end - src < 8 * 8) + return NULL; + for (i = 0; i < 8; i++) { memcpy(dst, src, 8); src += 8; @@ -119,11 +142,16 @@ static const unsigned char *seq_decode_op2(SeqVideoContext *seq, const unsigned return src; } -static const unsigned char *seq_decode_op3(SeqVideoContext *seq, const unsigned char *src, unsigned char *dst) +static const unsigned char *seq_decode_op3(SeqVideoContext *seq, + const unsigned char *src, + const unsigned char *src_end, + unsigned char *dst) { int pos, offset; do { + if (src_end - src < 2) + return NULL; pos = *src++; offset = ((pos >> 3) & 7) * seq->frame.linesize[0] + (pos & 7); dst[offset] = *src++; @@ -132,8 +160,9 @@ static const unsigned char *seq_decode_op3(SeqVideoContext *seq, const unsigned return src; } -static void seqvideo_decode(SeqVideoContext *seq, const unsigned char *data, int data_size) +static int seqvideo_decode(SeqVideoContext *seq, const unsigned char *data, int data_size) { + const unsigned char *data_end = data + data_size; GetBitContext gb; int flags, i, j, x, y, op; unsigned char c[3]; @@ -144,6 +173,8 @@ static void seqvideo_decode(SeqVideoContext *seq, const unsigned char *data, int if (flags & 1) { palette = (uint32_t *)seq->frame.data[1]; + if (data_end - data < 256 * 3) + return AVERROR_INVALIDDATA; for (i = 0; i < 256; i++) { for (j = 0; j < 3; j++, data++) c[j] = (*data << 2) | (*data >> 4); @@ -153,6 +184,8 @@ static void seqvideo_decode(SeqVideoContext *seq, const unsigned char *data, int } if (flags & 2) { + if (data_end - data < 128) + return AVERROR_INVALIDDATA; init_get_bits(&gb, data, 128 * 8); data += 128; for (y = 0; y < 128; y += 8) for (x = 0; x < 256; x += 8) { @@ -160,17 +193,20 @@ static void seqvideo_decode(SeqVideoContext *seq, const unsigned char *data, int op = get_bits(&gb, 2); switch (op) { case 1: - data = seq_decode_op1(seq, data, dst); + data = seq_decode_op1(seq, data, data_end, dst); break; case 2: - data = seq_decode_op2(seq, data, dst); + data = seq_decode_op2(seq, data, data_end, dst); break; case 3: - data = seq_decode_op3(seq, data, dst); + data = seq_decode_op3(seq, data, data_end, dst); break; } + if (!data) + return AVERROR_INVALIDDATA; } } + return 0; } static av_cold int seqvideo_decode_init(AVCodecContext *avctx) @@ -201,7 +237,8 @@ static int seqvideo_decode_frame(AVCodecContext *avctx, return -1; } - seqvideo_decode(seq, buf, buf_size); + if (seqvideo_decode(seq, buf, buf_size)) + return AVERROR_INVALIDDATA; *data_size = sizeof(AVFrame); *(AVFrame *)data = seq->frame; -- cgit v1.2.3