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[FFmpeg-devel] avformat/hls: Fixes overwriting existing #EXT-X-PROGRAM-DATE-TIME value in HLS playlist

Message ID 20201125051645.35202-1-vignesh.ravichandran02@gmail.com
State Superseded
Headers show
Series [FFmpeg-devel] avformat/hls: Fixes overwriting existing #EXT-X-PROGRAM-DATE-TIME value in HLS playlist
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Commit Message

Vignesh Ravichandran Nov. 25, 2020, 5:16 a.m. UTC
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.ravichandran02@gmail.com>
---
 libavformat/hlsenc.c | 35 +++++++++++++++++++++++++++++++----
 1 file changed, 31 insertions(+), 4 deletions(-)

Comments

Steven Liu Nov. 25, 2020, 5:59 a.m. UTC | #1
> 2020年11月25日 下午1:16,Vignesh Ravichandran <vignesh.ravichandran02@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.ravichandran02@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-request@ffmpeg.org with subject "unsubscribe".

Thanks

Steven Liu
Vignesh Ravichandran Nov. 25, 2020, 11:49 a.m. UTC | #2
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.

Thanks,
Vignesh

On Wed, Nov 25, 2020 at 11:29 AM Steven Liu <lq@chinaffmpeg.org> wrote:

>
>
> > 2020年11月25日 下午1:16,Vignesh Ravichandran <
> vignesh.ravichandran02@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.ravichandran02@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-request@ffmpeg.org with subject "unsubscribe".
>
> Thanks
>
> Steven Liu
>
>
>
>
Steven Liu Nov. 25, 2020, 12:01 p.m. UTC | #3
> 2020年11月25日 下午7:49,Vignesh Ravichandran <vignesh.ravichandran02@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 <lq@chinaffmpeg.org> wrote:
> 
>> 
>> 
>>> 2020年11月25日 下午1:16,Vignesh Ravichandran <
>> vignesh.ravichandran02@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.ravichandran02@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-request@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-request@ffmpeg.org with subject "unsubscribe".

Thanks

Steven Liu
Vignesh Ravichandran Nov. 25, 2020, 1:57 p.m. UTC | #4
Sure, how about the snippet below:

regex_t regex;
regcomp(&regex,
"([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(&regex, ptr, 0, NULL, 0) == REG_NOMATCH) {
  ret = AVERROR_INVALIDDATA;
  goto fail;
}

On Wed, Nov 25, 2020 at 5:31 PM Steven Liu <lq@chinaffmpeg.org> wrote:

>
>
> > 2020年11月25日 下午7:49,Vignesh Ravichandran <
> vignesh.ravichandran02@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 <lq@chinaffmpeg.org> wrote:
> >
> >>
> >>
> >>> 2020年11月25日 下午1:16,Vignesh Ravichandran <
> >> vignesh.ravichandran02@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.ravichandran02@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-request@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-request@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-request@ffmpeg.org with subject "unsubscribe".
Steven Liu Nov. 26, 2020, 2:29 a.m. UTC | #5
> 2020年11月25日 下午9:57,Vignesh Ravichandran <vignesh.ravichandran02@gmail.com> 写道:
> 
> Sure, how about the snippet below:
> 
> regex_t regex;
> regcomp(&regex,
> "([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(&regex, ptr, 0, NULL, 0) == REG_NOMATCH) {
>  ret = AVERROR_INVALIDDATA;
>  goto fail;
> }

Define a new function to check the value:
1. Split the string by ‘-‘
2. Check every value splited by ‘-‘
3. If the value is int, that is correct result.
4. Else not.
> 
> On Wed, Nov 25, 2020 at 5:31 PM Steven Liu <lq@chinaffmpeg.org> wrote:
> 
>> 
>> 
>>> 2020年11月25日 下午7:49,Vignesh Ravichandran <
>> vignesh.ravichandran02@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 <lq@chinaffmpeg.org> wrote:
>>> 
>>>> 
>>>> 
>>>>> 2020年11月25日 下午1:16,Vignesh Ravichandran <
>>>> vignesh.ravichandran02@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.ravichandran02@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-request@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-request@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-request@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-request@ffmpeg.org with subject "unsubscribe".

Thanks

Steven Liu
Vignesh Ravichandran Nov. 26, 2020, 4:43 a.m. UTC | #6
This check may not be enough. The below values would pass the check which
should not be the case:
20-11-26T08:34:00.000
2020-11-26T8:34:00.000
2020-11-26T08:60:00.000
2020-11-26T08:60:0.000
2020-13-26T08:34:00.000

The regex check approach mentioned earlier checks:
1. The value is in "YYYY-MM-DDThh:mm:ss.SSS" format (
https://tools.ietf.org/html/draft-pantos-http-live-streaming-23#section-4.3.2.6
)
2. The values for YYYY, MM, DD, hh, mm, ss, SSS are valid. For example: the
check would fail for MM = 00

On Thu, Nov 26, 2020 at 8:00 AM Steven Liu <lq@chinaffmpeg.org> wrote:

>
>
> > 2020年11月25日 下午9:57,Vignesh Ravichandran <
> vignesh.ravichandran02@gmail.com> 写道:
> >
> > Sure, how about the snippet below:
> >
> > regex_t regex;
> > regcomp(&regex,
> >
> "([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(&regex, ptr, 0, NULL, 0) == REG_NOMATCH) {
> >  ret = AVERROR_INVALIDDATA;
> >  goto fail;
> > }
>
> Define a new function to check the value:
> 1. Split the string by ‘-‘
> 2. Check every value splited by ‘-‘
> 3. If the value is int, that is correct result.
> 4. Else not.
> >
> > On Wed, Nov 25, 2020 at 5:31 PM Steven Liu <lq@chinaffmpeg.org> wrote:
> >
> >>
> >>
> >>> 2020年11月25日 下午7:49,Vignesh Ravichandran <
> >> vignesh.ravichandran02@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 <lq@chinaffmpeg.org>
> wrote:
> >>>
> >>>>
> >>>>
> >>>>> 2020年11月25日 下午1:16,Vignesh Ravichandran <
> >>>> vignesh.ravichandran02@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.ravichandran02@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-request@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-request@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-request@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-request@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-request@ffmpeg.org with subject "unsubscribe".
Steven Liu Nov. 26, 2020, 7:07 a.m. UTC | #7
> 2020年11月26日 下午12:43,Vignesh Ravichandran <vignesh.ravichandran02@gmail.com> 写道:
> 
> This check may not be enough. The below values would pass the check which should not be the case:
> 20-11-26T08:34:00.000
> 2020-11-26T8:34:00.000
> 2020-11-26T08:60:00.000
> 2020-11-26T08:60:0.000
> 2020-13-26T08:34:00.000
> 
> The regex check approach mentioned earlier checks:
> 1. The value is in "YYYY-MM-DDThh:mm:ss.SSS" format (https://tools.ietf.org/html/draft-pantos-http-live-streaming-23#section-4.3.2.6)
> 2. The values for YYYY, MM, DD, hh, mm, ss, SSS are valid. For example: the check would fail for MM = 00

1st split by T
2nd split by -
3rd split by :
4th the last value is double

And check the value :D

What about this?
> 
> On Thu, Nov 26, 2020 at 8:00 AM Steven Liu <lq@chinaffmpeg.org> wrote:
> 
> 
> > 2020年11月25日 下午9:57,Vignesh Ravichandran <vignesh.ravichandran02@gmail.com> 写道:
> > 
> > Sure, how about the snippet below:
> > 
> > regex_t regex;
> > regcomp(&regex,
> > "([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(&regex, ptr, 0, NULL, 0) == REG_NOMATCH) {
> >  ret = AVERROR_INVALIDDATA;
> >  goto fail;
> > }
> 
> Define a new function to check the value:
> 1. Split the string by ‘-‘
> 2. Check every value splited by ‘-‘
> 3. If the value is int, that is correct result.
> 4. Else not.
> > 
> > On Wed, Nov 25, 2020 at 5:31 PM Steven Liu <lq@chinaffmpeg.org> wrote:
> > 
> >> 
> >> 
> >>> 2020年11月25日 下午7:49,Vignesh Ravichandran <
> >> vignesh.ravichandran02@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 <lq@chinaffmpeg.org> wrote:
> >>> 
> >>>> 
> >>>> 
> >>>>> 2020年11月25日 下午1:16,Vignesh Ravichandran <
> >>>> vignesh.ravichandran02@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.ravichandran02@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-request@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-request@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-request@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-request@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-request@ffmpeg.org with subject "unsubscribe".

Thanks

Steven Liu
Vignesh Ravichandran Nov. 26, 2020, 2:58 p.m. UTC | #8
Sounds good :D I have incorporated the changes and resubmitted the patch -
http://ffmpeg.org/pipermail/ffmpeg-devel/2020-November/272964.html

Please review.

Thanks,
Vignesh

On Thu, Nov 26, 2020 at 12:37 PM Steven Liu <lq@chinaffmpeg.org> wrote:

>
>
> > 2020年11月26日 下午12:43,Vignesh Ravichandran <
> vignesh.ravichandran02@gmail.com> 写道:
> >
> > This check may not be enough. The below values would pass the check
> which should not be the case:
> > 20-11-26T08:34:00.000
> > 2020-11-26T8:34:00.000
> > 2020-11-26T08:60:00.000
> > 2020-11-26T08:60:0.000
> > 2020-13-26T08:34:00.000
> >
> > The regex check approach mentioned earlier checks:
> > 1. The value is in "YYYY-MM-DDThh:mm:ss.SSS" format (
> https://tools.ietf.org/html/draft-pantos-http-live-streaming-23#section-4.3.2.6
> )
> > 2. The values for YYYY, MM, DD, hh, mm, ss, SSS are valid. For example:
> the check would fail for MM = 00
>
> 1st split by T
> 2nd split by -
> 3rd split by :
> 4th the last value is double
>
> And check the value :D
>
> What about this?
> >
> > On Thu, Nov 26, 2020 at 8:00 AM Steven Liu <lq@chinaffmpeg.org> wrote:
> >
> >
> > > 2020年11月25日 下午9:57,Vignesh Ravichandran <
> vignesh.ravichandran02@gmail.com> 写道:
> > >
> > > Sure, how about the snippet below:
> > >
> > > regex_t regex;
> > > regcomp(&regex,
> > >
> "([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(&regex, ptr, 0, NULL, 0) == REG_NOMATCH) {
> > >  ret = AVERROR_INVALIDDATA;
> > >  goto fail;
> > > }
> >
> > Define a new function to check the value:
> > 1. Split the string by ‘-‘
> > 2. Check every value splited by ‘-‘
> > 3. If the value is int, that is correct result.
> > 4. Else not.
> > >
> > > On Wed, Nov 25, 2020 at 5:31 PM Steven Liu <lq@chinaffmpeg.org> wrote:
> > >
> > >>
> > >>
> > >>> 2020年11月25日 下午7:49,Vignesh Ravichandran <
> > >> vignesh.ravichandran02@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 <lq@chinaffmpeg.org>
> wrote:
> > >>>
> > >>>>
> > >>>>
> > >>>>> 2020年11月25日 下午1:16,Vignesh Ravichandran <
> > >>>> vignesh.ravichandran02@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.ravichandran02@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-request@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-request@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-request@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-request@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-request@ffmpeg.org with subject "unsubscribe".
>
> Thanks
>
> Steven Liu
>
>
>
>
diff mbox series

Patch

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);
+
+            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");
         }