[FFmpeg-devel] [PATCH v3] avformat/hls: change sequence number type to int64_t

"zhilizhao(赵志立)" quinkblack at foxmail.com
Fri Jan 22 09:16:25 EET 2021


Ping for review.

> On Jan 16, 2021, at 11:40 AM, Zhao Zhili <quinkblack at foxmail.com> wrote:
> 
> Fix atoi() overflow for large EXT-X-MEDIA-SEQUENCE.
> 
> The spec says the type of sequence number is uint64_t. Use int64_t
> here since current implementation requires it to be signed integer,
> and hlsenc use int64_t too.
> ---
> v3:
> handle MEDIA-SEQUENCE higher than INT64_MAX
> 
> v2:
> AV_WB32 -> AV_WB64
> 
> libavformat/hls.c | 56 +++++++++++++++++++++++++++--------------------
> 1 file changed, 32 insertions(+), 24 deletions(-)
> 
> diff --git a/libavformat/hls.c b/libavformat/hls.c
> index 619e4800de..af2468ad9b 100644
> --- a/libavformat/hls.c
> +++ b/libavformat/hls.c
> @@ -112,13 +112,13 @@ struct playlist {
>     int finished;
>     enum PlaylistType type;
>     int64_t target_duration;
> -    int start_seq_no;
> +    int64_t start_seq_no;
>     int n_segments;
>     struct segment **segments;
>     int needed;
>     int broken;
> -    int cur_seq_no;
> -    int last_seq_no;
> +    int64_t cur_seq_no;
> +    int64_t last_seq_no;
>     int m3u8_hold_counters;
>     int64_t cur_seg_offset;
>     int64_t last_load_time;
> @@ -199,7 +199,7 @@ typedef struct HLSContext {
>     int n_renditions;
>     struct rendition **renditions;
> 
> -    int cur_seq_no;
> +    int64_t cur_seq_no;
>     int m3u8_hold_counters;
>     int live_start_index;
>     int first_packet;
> @@ -722,7 +722,7 @@ static int parse_playlist(HLSContext *c, const char *url,
>     int is_http = av_strstart(url, "http", NULL);
>     struct segment **prev_segments = NULL;
>     int prev_n_segments = 0;
> -    int prev_start_seq_no = -1;
> +    int64_t prev_start_seq_no = -1;
> 
>     if (is_http && !in && c->http_persistent && c->playlist_pb) {
>         in = c->playlist_pb;
> @@ -808,10 +808,17 @@ static int parse_playlist(HLSContext *c, const char *url,
>                 goto fail;
>             pls->target_duration = strtoll(ptr, NULL, 10) * AV_TIME_BASE;
>         } else if (av_strstart(line, "#EXT-X-MEDIA-SEQUENCE:", &ptr)) {
> +            uint64_t seq_no;
>             ret = ensure_playlist(c, &pls, url);
>             if (ret < 0)
>                 goto fail;
> -            pls->start_seq_no = atoi(ptr);
> +            seq_no = strtoull(ptr, NULL, 10);
> +            if (seq_no > INT64_MAX) {
> +                av_log(c->ctx, AV_LOG_DEBUG, "MEDIA-SEQUENCE higher than "
> +                        "INT64_MAX, mask out the highest bit\n");
> +                seq_no &= INT64_MAX;
> +            }
> +            pls->start_seq_no = seq_no;
>         } else if (av_strstart(line, "#EXT-X-PLAYLIST-TYPE:", &ptr)) {
>             ret = ensure_playlist(c, &pls, url);
>             if (ret < 0)
> @@ -832,9 +839,9 @@ static int parse_playlist(HLSContext *c, const char *url,
>             if (has_iv) {
>                 memcpy(cur_init_section->iv, iv, sizeof(iv));
>             } else {
> -                int seq = pls->start_seq_no + pls->n_segments;
> +                int64_t seq = pls->start_seq_no + pls->n_segments;
>                 memset(cur_init_section->iv, 0, sizeof(cur_init_section->iv));
> -                AV_WB32(cur_init_section->iv + 12, seq);
> +                AV_WB64(cur_init_section->iv + 8, seq);
>             }
> 
>             if (key_type != KEY_NONE) {
> @@ -889,9 +896,9 @@ static int parse_playlist(HLSContext *c, const char *url,
>                 if (has_iv) {
>                     memcpy(seg->iv, iv, sizeof(iv));
>                 } else {
> -                    int seq = pls->start_seq_no + pls->n_segments;
> +                    int64_t seq = pls->start_seq_no + pls->n_segments;
>                     memset(seg->iv, 0, sizeof(seg->iv));
> -                    AV_WB32(seg->iv + 12, seq);
> +                    AV_WB64(seg->iv + 8, seq);
>                 }
> 
>                 if (key_type != KEY_NONE) {
> @@ -954,16 +961,17 @@ static int parse_playlist(HLSContext *c, const char *url,
>     if (prev_segments) {
>         if (pls->start_seq_no > prev_start_seq_no && c->first_timestamp != AV_NOPTS_VALUE) {
>             int64_t prev_timestamp = c->first_timestamp;
> -            int i, diff = pls->start_seq_no - prev_start_seq_no;
> +            int i;
> +            int64_t diff = pls->start_seq_no - prev_start_seq_no;
>             for (i = 0; i < prev_n_segments && i < diff; i++) {
>                 c->first_timestamp += prev_segments[i]->duration;
>             }
> -            av_log(c->ctx, AV_LOG_DEBUG, "Media sequence change (%d -> %d)"
> +            av_log(c->ctx, AV_LOG_DEBUG, "Media sequence change (%"PRId64" -> %"PRId64")"
>                    " reflected in first_timestamp: %"PRId64" -> %"PRId64"\n",
>                    prev_start_seq_no, pls->start_seq_no,
>                    prev_timestamp, c->first_timestamp);
>         } else if (pls->start_seq_no < prev_start_seq_no) {
> -            av_log(c->ctx, AV_LOG_WARNING, "Media sequence changed unexpectedly: %d -> %d\n",
> +            av_log(c->ctx, AV_LOG_WARNING, "Media sequence changed unexpectedly: %"PRId64" -> %"PRId64"\n",
>                    prev_start_seq_no, pls->start_seq_no);
>         }
>         free_segment_dynarray(prev_segments, prev_n_segments);
> @@ -991,7 +999,7 @@ static struct segment *current_segment(struct playlist *pls)
> 
> static struct segment *next_segment(struct playlist *pls)
> {
> -    int n = pls->cur_seq_no - pls->start_seq_no + 1;
> +    int64_t n = pls->cur_seq_no - pls->start_seq_no + 1;
>     if (n >= pls->n_segments)
>         return NULL;
>     return pls->segments[n];
> @@ -1457,7 +1465,7 @@ reload:
>         }
>         if (v->cur_seq_no < v->start_seq_no) {
>             av_log(v->parent, AV_LOG_WARNING,
> -                   "skipping %d segments ahead, expired from playlists\n",
> +                   "skipping %"PRId64" segments ahead, expired from playlists\n",
>                    v->start_seq_no - v->cur_seq_no);
>             v->cur_seq_no = v->start_seq_no;
>         }
> @@ -1503,7 +1511,7 @@ reload:
>         if (ret < 0) {
>             if (ff_check_interrupt(c->interrupt_callback))
>                 return AVERROR_EXIT;
> -            av_log(v->parent, AV_LOG_WARNING, "Failed to open segment %d of playlist %d\n",
> +            av_log(v->parent, AV_LOG_WARNING, "Failed to open segment %"PRId64" of playlist %d\n",
>                    v->cur_seq_no,
>                    v->index);
>             v->cur_seq_no += 1;
> @@ -1528,7 +1536,7 @@ reload:
>         if (ret < 0) {
>             if (ff_check_interrupt(c->interrupt_callback))
>                 return AVERROR_EXIT;
> -            av_log(v->parent, AV_LOG_WARNING, "Failed to open next segment %d of playlist %d\n",
> +            av_log(v->parent, AV_LOG_WARNING, "Failed to open segment %"PRId64" of playlist %d\n",
>                    v->cur_seq_no + 1,
>                    v->index);
>         } else {
> @@ -1625,7 +1633,7 @@ static void add_metadata_from_renditions(AVFormatContext *s, struct playlist *pl
> /* if timestamp was in valid range: returns 1 and sets seq_no
>  * if not: returns 0 and sets seq_no to closest segment */
> static int find_timestamp_in_playlist(HLSContext *c, struct playlist *pls,
> -                                      int64_t timestamp, int *seq_no)
> +                                      int64_t timestamp, int64_t *seq_no)
> {
>     int i;
>     int64_t pos = c->first_timestamp == AV_NOPTS_VALUE ?
> @@ -1650,9 +1658,9 @@ static int find_timestamp_in_playlist(HLSContext *c, struct playlist *pls,
>     return 0;
> }
> 
> -static int select_cur_seq_no(HLSContext *c, struct playlist *pls)
> +static int64_t select_cur_seq_no(HLSContext *c, struct playlist *pls)
> {
> -    int seq_no;
> +    int64_t seq_no;
> 
>     if (!pls->finished && !c->first_packet &&
>         av_gettime_relative() - pls->last_load_time >= default_reload_interval(pls))
> @@ -1844,7 +1852,7 @@ static int hls_read_header(AVFormatContext *s)
> {
>     HLSContext *c = s->priv_data;
>     int ret = 0, i;
> -    int highest_cur_seq_no = 0;
> +    int64_t highest_cur_seq_no = 0;
> 
>     c->ctx                = s;
>     c->interrupt_callback = &s->interrupt_callback;
> @@ -2077,7 +2085,7 @@ static int recheck_discard_flags(AVFormatContext *s, int first)
>                 pls->seek_flags = AVSEEK_FLAG_ANY;
>                 pls->seek_stream_index = -1;
>             }
> -            av_log(s, AV_LOG_INFO, "Now receiving playlist %d, segment %d\n", i, pls->cur_seq_no);
> +            av_log(s, AV_LOG_INFO, "Now receiving playlist %d, segment %"PRId64"\n", i, pls->cur_seq_no);
>         } else if (first && !cur_needed && pls->needed) {
>             ff_format_io_close(pls->parent, &pls->input);
>             pls->input_read_done = 0;
> @@ -2274,10 +2282,10 @@ static int hls_read_seek(AVFormatContext *s, int stream_index,
> {
>     HLSContext *c = s->priv_data;
>     struct playlist *seek_pls = NULL;
> -    int i, seq_no;
> -    int j;
> +    int i, j;
>     int stream_subdemuxer_index;
>     int64_t first_timestamp, seek_timestamp, duration;
> +    int64_t seq_no;
> 
>     if ((flags & AVSEEK_FLAG_BYTE) || (c->ctx->ctx_flags & AVFMTCTX_UNSEEKABLE))
>         return AVERROR(ENOSYS);
> -- 
> 2.27.0
> 
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