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| author | Ronald S. Bultje <rsbultje@gmail.com> | 2012-03-10 11:57:17 -0800 |
|---|---|---|
| committer | Ronald S. Bultje <rsbultje@gmail.com> | 2012-03-10 11:57:17 -0800 |
| commit | f77bfa837636a99a4034d31916a76f7d1688cf5a (patch) | |
| tree | 8bc3a9a7fe5aab4373502278b71f8d276142fc1e /libavcodec/xxan.c | |
| parent | 55188278169c3a1838334d7aa47a1f7a40741690 (diff) | |
| download | ffmpeg-f77bfa837636a99a4034d31916a76f7d1688cf5a.tar.gz | |
xxan: protect against chroma LUT overreads.
Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
CC: libav-stable@libav.org
Diffstat (limited to 'libavcodec/xxan.c')
| -rw-r--r-- | libavcodec/xxan.c | 14 |
1 files changed, 8 insertions, 6 deletions
diff --git a/libavcodec/xxan.c b/libavcodec/xxan.c index 86b4195ce4..dd5447940b 100644 --- a/libavcodec/xxan.c +++ b/libavcodec/xxan.c @@ -162,7 +162,7 @@ static int xan_decode_chroma(AVCodecContext *avctx, unsigned chroma_off) int i, j; const uint8_t *src, *src_end; const uint8_t *table; - int mode, offset, dec_size; + int mode, offset, dec_size, table_size; if (!chroma_off) return 0; @@ -171,9 +171,11 @@ static int xan_decode_chroma(AVCodecContext *avctx, unsigned chroma_off) return -1; } bytestream2_seek(&s->gb, chroma_off + 4, SEEK_SET); - mode = bytestream2_get_le16(&s->gb); - table = s->gb.buffer; - offset = bytestream2_get_le16(&s->gb) * 2; + mode = bytestream2_get_le16(&s->gb); + table = s->gb.buffer; + table_size = bytestream2_get_le16(&s->gb); + offset = table_size * 2; + table_size += 1; if (offset >= bytestream2_get_bytes_left(&s->gb)) { av_log(avctx, AV_LOG_ERROR, "Invalid chroma block offset\n"); @@ -196,7 +198,7 @@ static int xan_decode_chroma(AVCodecContext *avctx, unsigned chroma_off) for (j = 0; j < avctx->height >> 1; j++) { for (i = 0; i < avctx->width >> 1; i++) { val = *src++; - if (val) { + if (val && val < table_size) { val = AV_RL16(table + (val << 1)); uval = (val >> 3) & 0xF8; vval = (val >> 8) & 0xF8; @@ -216,7 +218,7 @@ static int xan_decode_chroma(AVCodecContext *avctx, unsigned chroma_off) for (j = 0; j < avctx->height >> 2; j++) { for (i = 0; i < avctx->width >> 1; i += 2) { val = *src++; - if (val) { + if (val && val < table_size) { val = AV_RL16(table + (val << 1)); uval = (val >> 3) & 0xF8; vval = (val >> 8) & 0xF8; |