From e2e145db89913e86e9b8573b1b90f001c46dee5e Mon Sep 17 00:00:00 2001 From: wm4 Date: Mon, 5 Jan 2015 04:45:26 +0100 Subject: [PATCH] avcodec/dvdsubdec: fix out of bounds accesses The code blindly trusted buffer offsets read from the file in the RLE decoder. Explicitly check the offset. Also error out on other RLE decoding errors. Signed-off-by: Michael Niedermayer (cherry picked from commit c9151de7c42553bb145be608df8513c1287f1f24) Signed-off-by: Michael Niedermayer --- libavcodec/dvdsubdec.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) diff --git a/libavcodec/dvdsubdec.c b/libavcodec/dvdsubdec.c index 7355c03ec2..5e225566b7 100644 --- a/libavcodec/dvdsubdec.c +++ b/libavcodec/dvdsubdec.c @@ -105,6 +105,9 @@ static int decode_rle(uint8_t *bitmap, int linesize, int w, int h, int x, y, len, color; uint8_t *d; + if (start >= buf_size) + return -1; + bit_len = (buf_size - start) * 8; init_get_bits(&gb, buf + start, bit_len); @@ -356,10 +359,12 @@ static int decode_dvd_subtitles(DVDSubContext *ctx, AVSubtitle *sub_header, sub_header->rects[0] = av_mallocz(sizeof(AVSubtitleRect)); sub_header->num_rects = 1; sub_header->rects[0]->pict.data[0] = bitmap; - decode_rle(bitmap, w * 2, w, (h + 1) / 2, - buf, offset1, buf_size, is_8bit); - decode_rle(bitmap + w, w * 2, w, h / 2, - buf, offset2, buf_size, is_8bit); + if (decode_rle(bitmap, w * 2, w, (h + 1) / 2, + buf, offset1, buf_size, is_8bit) < 0) + goto fail; + if (decode_rle(bitmap + w, w * 2, w, h / 2, + buf, offset2, buf_size, is_8bit) < 0) + goto fail; sub_header->rects[0]->pict.data[1] = av_mallocz(AVPALETTE_SIZE); if (is_8bit) { if (!yuv_palette)