Sure, how about the snippet below: regex_t regex; regcomp(®ex, "([12][0-9]{3}-(0[1-9]|1[0-2])-(0[1-9]|[12][0-9]|3[01])T([01][1-9]|2[0-3]):([0-5][0-9]):([0-5][0-9]).([0-9]{3}))", REG_EXTENDED); if (regexec(®ex, ptr, 0, NULL, 0) == REG_NOMATCH) { ret = AVERROR_INVALIDDATA; goto fail; }
On Wed, Nov 25, 2020 at 5:31 PM Steven Liu <l...@chinaffmpeg.org> wrote: > > > > 2020年11月25日 下午7:49,Vignesh Ravichandran < > vignesh.ravichandra...@gmail.com> 写道: > > > > We could add a simple check like below to prevent it: > > > > if (sscanf(ptr, "%d-%d-%dT%d:%d:%d.%lf", &y, &M, &d, &h, &m, &s, &ms) != > 7) > > { > > ret = AVERROR_INVALIDDATA; > > goto fail; > > } > > > > Please let me know. > Not sure this is better way, what about validate the string of the > "#EXT-X-PROGRAM-DATE-TIME” values? > > > > > > Thanks, > > Vignesh > > > > On Wed, Nov 25, 2020 at 11:29 AM Steven Liu <l...@chinaffmpeg.org> wrote: > > > >> > >> > >>> 2020年11月25日 下午1:16,Vignesh Ravichandran < > >> vignesh.ravichandra...@gmail.com> 写道: > >>> > >>> Bug ID: 8989 > >>> > >>> This is is due to the following behavior in the current code: > >>> 1. The initial_prog_date_time gets set to the current local time > >>> 2. The existing playlist (.m3u8) file gets parsed and the segments > >> present are added to the variant stream > >>> 3. The new segment is created and added > >>> 4. The existing segments and the new segment are written to the > playlist > >> file. The initial_prog_date_time from point 1 is used for calculating > >> "#EXT-X-PROGRAM-DATE-TIME" for the segments, which results in incorrect > >> "#EXT-X-PROGRAM-DATE-TIME" values for existing segments > >>> > >>> The following approach fixes this bug: > >>> 1. Add a new variable "discont_program_date_time" of type double to > >> HLSSegment struct > >>> 2. Store the "EXT-X-PROGRAM-DATE-TIME" value from the existing segments > >> in this variable > >>> 3. When writing to playlist file if "discont_program_date_time" is set, > >> then use that value for "EXT-X-PROGRAM-DATE-TIME" else use the value > >> present in vs->initial_prog_date_time > >>> > >>> Signed-off-by: Vignesh Ravichandran <vignesh.ravichandra...@gmail.com> > >>> --- > >>> libavformat/hlsenc.c | 35 +++++++++++++++++++++++++++++++---- > >>> 1 file changed, 31 insertions(+), 4 deletions(-) > >>> > >>> diff --git a/libavformat/hlsenc.c b/libavformat/hlsenc.c > >>> index cbfd8f7c0d..030a2d3b97 100644 > >>> --- a/libavformat/hlsenc.c > >>> +++ b/libavformat/hlsenc.c > >>> @@ -88,6 +88,7 @@ typedef struct HLSSegment { > >>> char iv_string[KEYSIZE*2 + 1]; > >>> > >>> struct HLSSegment *next; > >>> + double discont_program_date_time; > >>> } HLSSegment; > >>> > >>> typedef enum HLSFlags { > >>> @@ -1124,6 +1125,7 @@ static int hls_append_segment(struct > >> AVFormatContext *s, HLSContext *hls, > >>> en->keyframe_size = vs->video_keyframe_size; > >>> en->next = NULL; > >>> en->discont = 0; > >>> + en->discont_program_date_time = 0; > >>> > >>> if (vs->discontinuity) { > >>> en->discont = 1; > >>> @@ -1148,7 +1150,8 @@ static int hls_append_segment(struct > >> AVFormatContext *s, HLSContext *hls, > >>> > >>> if (hls->max_nb_segments && vs->nb_entries >= hls->max_nb_segments) > { > >>> en = vs->segments; > >>> - vs->initial_prog_date_time += en->duration; > >>> + if (!en->next->discont_program_date_time && > >> !en->discont_program_date_time) > >>> + vs->initial_prog_date_time += en->duration; > >>> vs->segments = en->next; > >>> if (en && hls->flags & HLS_DELETE_SEGMENTS && > >>> #if FF_API_HLS_WRAP > >>> @@ -1182,6 +1185,8 @@ static int parse_playlist(AVFormatContext *s, > >> const char *url, VariantStream *vs > >>> char line[MAX_URL_SIZE]; > >>> const char *ptr; > >>> const char *end; > >>> + int is_discont_detected = 0; > >>> + double discont_program_date_time = 0; > >>> > >>> if ((ret = ffio_open_whitelist(&in, url, AVIO_FLAG_READ, > >>> &s->interrupt_callback, NULL, > >>> @@ -1211,6 +1216,7 @@ static int parse_playlist(AVFormatContext *s, > >> const char *url, VariantStream *vs > >>> } else if (av_strstart(line, "#EXT-X-DISCONTINUITY", &ptr)) { > >>> is_segment = 1; > >>> vs->discontinuity = 1; > >>> + is_discont_detected = 1; > >>> } else if (av_strstart(line, "#EXTINF:", &ptr)) { > >>> is_segment = 1; > >>> vs->duration = atof(ptr); > >>> @@ -1236,7 +1242,23 @@ static int parse_playlist(AVFormatContext *s, > >> const char *url, VariantStream *vs > >>> av_strlcpy(vs->iv_string, ptr, > >> sizeof(vs->iv_string)); > >>> } > >>> } > >>> - > >>> + } else if (av_strstart(line, "#EXT-X-PROGRAM-DATE-TIME:", > &ptr) > >> && is_discont_detected) { > >>> + struct tm program_date_time; > >>> + int y,M,d,h,m,s; > >>> + double ms; > >>> + sscanf(ptr, "%d-%d-%dT%d:%d:%d.%lf", &y, &M, &d, &h, &m, > >> &s, &ms); > >> What will happen if I modify the value of “EXT-X-PROGRAM-DATE-TIME” by > >> hacker, > >> For example: > >> #EXT-X-PROGRAM-DATA-TIME: good-morning-ladies-and-gentlemen. > >> > >>> + > >>> + program_date_time.tm_year = y - 1900; > >>> + program_date_time.tm_mon = M - 1; > >>> + program_date_time.tm_mday = d; > >>> + program_date_time.tm_hour = h; > >>> + program_date_time.tm_min = m; > >>> + program_date_time.tm_sec = s; > >>> + program_date_time.tm_isdst = -1; > >>> + > >>> + discont_program_date_time = mktime(&program_date_time); > >>> + discont_program_date_time += (double)(ms / 1000); > >>> + is_discont_detected = 0; > >>> } else if (av_strstart(line, "#", NULL)) { > >>> continue; > >>> } else if (line[0]) { > >>> @@ -1250,8 +1272,9 @@ static int parse_playlist(AVFormatContext *s, > >> const char *url, VariantStream *vs > >>> is_segment = 0; > >>> new_start_pos = avio_tell(vs->avf->pb); > >>> vs->size = new_start_pos - vs->start_pos; > >>> - vs->initial_prog_date_time -= vs->duration; // this is > >> a previously existing segment > >>> ret = hls_append_segment(s, hls, vs, vs->duration, > >> vs->start_pos, vs->size); > >>> + vs->last_segment->discont_program_date_time = > >> discont_program_date_time; > >>> + discont_program_date_time += vs->duration; > >>> if (ret < 0) > >>> goto fail; > >>> vs->start_pos = new_start_pos; > >>> @@ -1572,7 +1595,11 @@ static int hls_window(AVFormatContext *s, int > >> last, VariantStream *vs) > >>> ret = ff_hls_write_file_entry(byterange_mode ? hls->m3u8_out : > >> vs->out, en->discont, byterange_mode, > >>> en->duration, hls->flags & > >> HLS_ROUND_DURATIONS, > >>> en->size, en->pos, hls->baseurl, > >>> - en->filename, prog_date_time_p, > >> en->keyframe_size, en->keyframe_pos, hls->flags & HLS_I_FRAMES_ONLY); > >>> + en->filename, > >>> + en->discont_program_date_time ? > >> &en->discont_program_date_time : prog_date_time_p, > >>> + en->keyframe_size, > >> en->keyframe_pos, hls->flags & HLS_I_FRAMES_ONLY); > >>> + if (en->discont_program_date_time) > >>> + en->discont_program_date_time -= en->duration; > >>> if (ret < 0) { > >>> av_log(s, AV_LOG_WARNING, "ff_hls_write_file_entry get > >> error\n"); > >>> } > >>> -- > >>> 2.24.2 (Apple Git-127) > >>> > >>> _______________________________________________ > >>> ffmpeg-devel mailing list > >>> ffmpeg-devel@ffmpeg.org > >>> https://ffmpeg.org/mailman/listinfo/ffmpeg-devel > >>> > >>> To unsubscribe, visit link above, or email > >>> ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe". > >> > >> Thanks > >> > >> Steven Liu > >> > >> > >> > >> > > _______________________________________________ > > ffmpeg-devel mailing list > > ffmpeg-devel@ffmpeg.org > > https://ffmpeg.org/mailman/listinfo/ffmpeg-devel > > > > To unsubscribe, visit link above, or email > > ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe". > > Thanks > > Steven Liu > > > > _______________________________________________ > ffmpeg-devel mailing list > ffmpeg-devel@ffmpeg.org > https://ffmpeg.org/mailman/listinfo/ffmpeg-devel > > To unsubscribe, visit link above, or email > ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe". _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".