[FFmpeg-devel] [PATCH v2] libaf/hlsenc: allow dynamic encryption key rotation

[Steven Liu]

2017-08-05 11:36 GMT+08:00 DeHackEd <git at dehacked.net>:
> Makes behaviour of 805ce25b1d2f optional, re-enables
> HLS key rotation feature
>
> Signed-off-by: DHE <git at dehacked.net>
> ---
>  doc/muxers.texi      | 7 ++++++-
>  libavformat/hlsenc.c | 4 +++-
>  2 files changed, 9 insertions(+), 2 deletions(-)
>
> v1->v2: Actually works this time
>
> diff --git a/doc/muxers.texi b/doc/muxers.texi
> index 94472ce..a7324a4 100644
> --- a/doc/muxers.texi
> +++ b/doc/muxers.texi
> @@ -551,7 +551,7 @@ format. The optional third line specifies the initialization vector (IV) as a
>  hexadecimal string to be used instead of the segment sequence number (default)
>  for encryption. Changes to @var{key_info_file} will result in segment
>  encryption with the new key/IV and an entry in the playlist for the new key
> -URI/IV.
> +URI/IV if @code{hls_flags periodic_rekey} is enabled.
>
>  Key info file format:
>  @example
> @@ -665,6 +665,11 @@ first segment's information.
>  @item omit_endlist
>  Do not append the @code{EXT-X-ENDLIST} tag at the end of the playlist.
>
> + at item periodic_rekey
> +The file specified by @code{hls_key_info} will be checked periodically and
> +detect updates to the encryption info. Be sure to replace this file atomically,
> +including the file containing the AES encryption key.
> +
>  @item split_by_time
>  Allow segments to start on frames other than keyframes. This improves
>  behavior on some players when the time between keyframes is inconsistent,
> diff --git a/libavformat/hlsenc.c b/libavformat/hlsenc.c
> index 5cf8c89..74a3249 100644
> --- a/libavformat/hlsenc.c
> +++ b/libavformat/hlsenc.c
> @@ -85,6 +85,7 @@ typedef enum HLSFlags {
>      HLS_SECOND_LEVEL_SEGMENT_DURATION = (1 << 9), // include segment duration (microsec) in segment filenames when use_localtime  e.g.: %%09t
>      HLS_SECOND_LEVEL_SEGMENT_SIZE = (1 << 10), // include segment size (bytes) in segment filenames when use_localtime  e.g.: %%014s
>      HLS_TEMP_FILE = (1 << 11),
> +    HLS_PERIODIC_REKEY = (1 << 12),
>  } HLSFlags;
>
>  typedef enum {
> @@ -1236,7 +1237,7 @@ static int hls_start(AVFormatContext *s)
>                    " will use -hls_key_info_file priority\n");
>          }
>
> -        if (c->number <= 1) {
> +        if (c->number <= 1 || (c->flags & HLS_PERIODIC_REKEY)) {
>              if (c->key_info_file) {
>                  if ((err = hls_encryption_start(s)) < 0)
>                      goto fail;
> @@ -1804,6 +1805,7 @@ static const AVOption options[] = {
>      {"second_level_segment_index", "include segment index in segment filenames when use_localtime", 0, AV_OPT_TYPE_CONST, {.i64 = HLS_SECOND_LEVEL_SEGMENT_INDEX }, 0, UINT_MAX,   E, "flags"},
>      {"second_level_segment_duration", "include segment duration in segment filenames when use_localtime", 0, AV_OPT_TYPE_CONST, {.i64 = HLS_SECOND_LEVEL_SEGMENT_DURATION }, 0, UINT_MAX,   E, "flags"},
>      {"second_level_segment_size", "include segment size in segment filenames when use_localtime", 0, AV_OPT_TYPE_CONST, {.i64 = HLS_SECOND_LEVEL_SEGMENT_SIZE }, 0, UINT_MAX,   E, "flags"},
> +    {"periodic_rekey", "reload keyinfo file periodically for re-keying", 0, AV_OPT_TYPE_CONST, {.i64 = HLS_PERIODIC_REKEY }, 0, UINT_MAX,   E, "flags"},
>      {"use_localtime", "set filename expansion with strftime at segment creation", OFFSET(use_localtime), AV_OPT_TYPE_BOOL, {.i64 = 0 }, 0, 1, E },
>      {"use_localtime_mkdir", "create last directory component in strftime-generated filename", OFFSET(use_localtime_mkdir), AV_OPT_TYPE_BOOL, {.i64 = 0 }, 0, 1, E },
>      {"hls_playlist_type", "set the HLS playlist type", OFFSET(pl_type), AV_OPT_TYPE_INT, {.i64 = PLAYLIST_TYPE_NONE }, 0, PLAYLIST_TYPE_NB-1, E, "pl_type" },
> --
> 1.8.4.1
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LGTM