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

[DeHackEd]

Signed-off-by: DHE <git at dehacked.net>
---
 doc/muxers.texi      | 7 ++++++-
 libavformat/hlsenc.c | 4 +++-
 2 files changed, 9 insertions(+), 2 deletions(-)

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..4d2e7fb 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