| Message ID | 20221022210226.2200-5-jamrial@gmail.com |
|---|---|
| State | Accepted |
| Commit | 4c35bb53f94e4de88a0919346f24d34f8387771c |
| Headers | show |
| Series | [FFmpeg-devel,1/5,v2] avcodec/ac3dec: split off code discarding garbage at the beginning of a packet | expand |
| Context | Check | Description |
|---|---|---|
| andriy/commit_msg_x86 | warning | Please wrap lines in the body of the commit message between 60 and 72 characters. |
| yinshiyou/commit_msg_loongarch64 | warning | Please wrap lines in the body of the commit message between 60 and 72 characters. |
| yinshiyou/make_loongarch64 | success | Make finished |
| yinshiyou/make_fate_loongarch64 | fail | Make fate failed |
| andriy/make_x86 | success | Make finished |
| andriy/make_fate_x86 | fail | Make fate failed |
diff --git a/libavcodec/aac_ac3_parser.c b/libavcodec/aac_ac3_parser.c index e89b12baf9..2b0ee61b6d 100644 --- a/libavcodec/aac_ac3_parser.c +++ b/libavcodec/aac_ac3_parser.c @@ -113,6 +113,10 @@ get_next: buf_size -= hdr.frame_size; continue; } + /* Check for false positives since the syncword is not enough. + See section 6.1.2 of A/52. */ + if (av_crc(s->crc_ctx, 0, buf + 2, hdr.frame_size - 2)) + return i; break; } diff --git a/libavcodec/aac_ac3_parser.h b/libavcodec/aac_ac3_parser.h index 560bba54f5..bc16181a19 100644 --- a/libavcodec/aac_ac3_parser.h +++ b/libavcodec/aac_ac3_parser.h @@ -24,6 +24,7 @@ #define AVCODEC_AAC_AC3_PARSER_H #include <stdint.h> +#include "libavutil/crc.h" #include "avcodec.h" #include "parser.h" @@ -42,6 +43,7 @@ typedef struct AACAC3ParseContext { int header_size; int (*sync)(uint64_t state, int *need_next_header, int *new_frame_start); + const AVCRC *crc_ctx; int remaining_size; uint64_t state; diff --git a/libavcodec/ac3_parser.c b/libavcodec/ac3_parser.c index 8885e1c72e..13b8d3b7d8 100644 --- a/libavcodec/ac3_parser.c +++ b/libavcodec/ac3_parser.c @@ -246,6 +246,7 @@ static av_cold int ac3_parse_init(AVCodecParserContext *s1) { AACAC3ParseContext *s = s1->priv_data; s->header_size = AC3_HEADER_SIZE; + s->crc_ctx = av_crc_get_table(AV_CRC_16_ANSI); s->sync = ac3_sync; return 0; }
A two byte sync word is not enough to ensure we got a real syncframe, nor are all the range checks we do in the first seven bytes. Do therefore an integrity check for the sync frame in order to prevent the parser from filling avctx with bogus information. Signed-off-by: James Almer <jamrial@gmail.com> --- libavcodec/aac_ac3_parser.c | 4 ++++ libavcodec/aac_ac3_parser.h | 2 ++ libavcodec/ac3_parser.c | 1 + 3 files changed, 7 insertions(+)