diff options
author | Vesselin Bontchev <vesselin.bontchev@yandex.com> | 2000-01-01 09:00:00 +0000 |
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committer | Vesselin Bontchev <vesselin.bontchev@yandex.com> | 2020-11-05 21:40:20 +0530 |
commit | 03fb314acfa4f5a4af84a6fc82a425477fd352eb (patch) | |
tree | 51d799425284a10a0e497d54556472de76d2c9dd /libavformat/mov.c | |
parent | 70d8077b795766e2486e6ec8110f22a97362d6d6 (diff) |
Add support for playing Audible AAXC (.aaxc) files [PATCH v4]
The AAXC container format is the same as the (already supported) Audible
AAX format but it uses a different encryption scheme.
Note: audible_key and audible_iv values are variable (per file) and are
externally fed.
It is possible to extend https://github.com/mkb79/Audible to derive the
audible_key and audible_key values.
Relevant code:
def decrypt_voucher(deviceSerialNumber, customerId, deviceType, asin, voucher):
buf = (deviceType + deviceSerialNumber + customerId + asin).encode("ascii")
digest = hashlib.sha256(buf).digest()
key = digest[0:16]
iv = digest[16:]
# decrypt "voucher" using AES in CBC mode with no padding
cipher = AES.new(key, AES.MODE_CBC, iv)
plaintext = cipher.decrypt(voucher).rstrip(b"\x00") # improve this!
return json.loads(plaintext)
The decrypted "voucher" has the required audible_key and audible_iv
values.
Update (Nov-2020): This patch has now been tested by multiple folks -
details at the following URL:
https://github.com/mkb79/Audible/issues/3
Signed-off-by: Vesselin Bontchev <vesselin.bontchev@yandex.com>
Diffstat (limited to 'libavformat/mov.c')
-rw-r--r-- | libavformat/mov.c | 33 |
1 files changed, 33 insertions, 0 deletions
diff --git a/libavformat/mov.c b/libavformat/mov.c index dd0db6bca7..2b90e31170 100644 --- a/libavformat/mov.c +++ b/libavformat/mov.c @@ -1075,6 +1075,30 @@ fail: return ret; } +static int mov_aaxc_crypto(MOVContext *c) +{ + if (c->audible_key_size != 16) { + av_log(c->fc, AV_LOG_FATAL, "[aaxc] audible_key value needs to be 16 bytes!\n"); + return AVERROR(EINVAL); + } + + if (c->audible_iv_size != 16) { + av_log(c->fc, AV_LOG_FATAL, "[aaxc] audible_iv value needs to be 16 bytes!\n"); + return AVERROR(EINVAL); + } + + c->aes_decrypt = av_aes_alloc(); + if (!c->aes_decrypt) { + return AVERROR(ENOMEM); + } + + memcpy(c->file_key, c->audible_key, 16); + memcpy(c->file_iv, c->audible_iv, 16); + c->aax_mode = 1; + + return 0; +} + // Audible AAX (and AAX+) bytestream decryption static int aax_filter(uint8_t *input, int size, MOVContext *c) { @@ -1123,6 +1147,11 @@ static int mov_read_ftyp(MOVContext *c, AVIOContext *pb, MOVAtom atom) av_dict_set(&c->fc->metadata, "compatible_brands", comp_brands_str, AV_DICT_DONT_STRDUP_VAL); + // Logic for handling Audible's .aaxc files + if (!strcmp(type, "aaxc")) { + mov_aaxc_crypto(c); + } + return 0; } @@ -8170,6 +8199,10 @@ static const AVOption mov_options[] = { AV_OPT_TYPE_BOOL, { .i64 = 0 }, 0, 1, .flags = FLAGS }, { "activation_bytes", "Secret bytes for Audible AAX files", OFFSET(activation_bytes), AV_OPT_TYPE_BINARY, .flags = AV_OPT_FLAG_DECODING_PARAM }, + { "audible_key", "AES-128 Key for Audible AAXC files", OFFSET(audible_key), + AV_OPT_TYPE_BINARY, .flags = AV_OPT_FLAG_DECODING_PARAM }, + { "audible_iv", "AES-128 IV for Audible AAXC files", OFFSET(audible_iv), + AV_OPT_TYPE_BINARY, .flags = AV_OPT_FLAG_DECODING_PARAM }, { "audible_fixed_key", // extracted from libAAX_SDK.so and AAXSDKWin.dll files! "Fixed key used for handling Audible AAX files", OFFSET(audible_fixed_key), AV_OPT_TYPE_BINARY, {.str="77214d4b196a87cd520045fd20a51d67"}, |