libaacs | branch: master | npzacs <npz...@gmail.com> | Mon Jan 5 17:22:06 2015 +0200| [d8ca79150784d9b1896557dc170646a38917cab8] | committer: npzacs
Do in-place decryption without memcpy() > http://git.videolan.org/gitweb.cgi/libaacs.git/?a=commit;h=d8ca79150784d9b1896557dc170646a38917cab8 --- src/libaacs/aacs.c | 59 +++++++++++++++++++++++++++++++++++----------------- 1 file changed, 40 insertions(+), 19 deletions(-) diff --git a/src/libaacs/aacs.c b/src/libaacs/aacs.c index 02eb409..18f2537 100644 --- a/src/libaacs/aacs.c +++ b/src/libaacs/aacs.c @@ -70,6 +70,7 @@ struct aacs { /* CPS unit of currently selected title */ uint16_t current_cps_unit; + uint8_t cps_unit_selected; /* title -> CPS unit mappings */ uint32_t num_titles; @@ -85,10 +86,10 @@ struct aacs { uint8_t device_binding_id[16]; }; -static const uint8_t empty_key[] = "\x00\x00\x00\x00\x00\x00\x00\x00" - "\x00\x00\x00\x00\x00\x00\x00\x00"; -static const uint8_t aacs_iv[] = "\x0b\xa0\xf8\xdd\xfe\xa6\x1f\xb3" - "\xd8\xdf\x9f\x56\x6a\x05\x0f\x78"; +static const uint8_t empty_key[16] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, + 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 }; +static const uint8_t aacs_iv[16] = { 0x0b, 0xa0, 0xf8, 0xdd, 0xfe, 0xa6, 0x1f, 0xb3, + 0xd8, 0xdf, 0x9f, 0x56, 0x6a, 0x05, 0x0f, 0x78 }; static int _validate_pk(const uint8_t *pk, const uint8_t *cvalue, const uint8_t *uv, const uint8_t *vd, @@ -899,35 +900,39 @@ static int _verify_ts(uint8_t *buf) static int _decrypt_unit(AACS *aacs, uint8_t *out_buf, const uint8_t *in_buf, uint32_t curr_uk) { + /* inbuf == NULL means in-place decryption */ + gcry_cipher_hd_t gcry_h; int a; uint8_t key[16]; + if (AACS_UNLIKELY(in_buf != NULL)) { + memcpy(out_buf, in_buf, 16); /* first 16 bytes are plain */ + } + gcry_cipher_open(&gcry_h, GCRY_CIPHER_AES, GCRY_CIPHER_MODE_ECB, 0); gcry_cipher_setkey(gcry_h, aacs->uks + curr_uk * 16, 16); - gcry_cipher_encrypt(gcry_h, key, 16, in_buf, 16); + gcry_cipher_encrypt(gcry_h, key, 16, out_buf, 16); /* here out_buf is plain data fron in_buf */ gcry_cipher_close(gcry_h); for (a = 0; a < 16; a++) { - key[a] ^= in_buf[a]; + key[a] ^= out_buf[a]; /* here out_buf is plain data fron in_buf */ } - memcpy(out_buf, in_buf, 16); /* first 16 bytes are plain */ - gcry_cipher_open(&gcry_h, GCRY_CIPHER_AES, GCRY_CIPHER_MODE_CBC, 0); gcry_cipher_setkey(gcry_h, key, 16); gcry_cipher_setiv(gcry_h, aacs_iv, 16); - gcry_cipher_decrypt(gcry_h, out_buf + 16, ALIGNED_UNIT_LEN - 16, in_buf + 16, ALIGNED_UNIT_LEN - 16); + if (AACS_UNLIKELY(in_buf != NULL)) { + gcry_cipher_decrypt(gcry_h, out_buf + 16, ALIGNED_UNIT_LEN - 16, in_buf + 16, ALIGNED_UNIT_LEN - 16); + } else { + gcry_cipher_decrypt(gcry_h, out_buf + 16, ALIGNED_UNIT_LEN - 16, NULL, 0); + } gcry_cipher_close(gcry_h); if (_verify_ts(out_buf)) { return 1; } - if (curr_uk < aacs->num_uks - 1) { - return _decrypt_unit(aacs, out_buf, in_buf, curr_uk++); - } - return 0; } @@ -1062,28 +1067,42 @@ void aacs_close(AACS *aacs) int aacs_decrypt_unit(AACS *aacs, uint8_t *buf) { - uint8_t out_buf[ALIGNED_UNIT_LEN]; - int i; + unsigned int i; if (!(buf[0] & 0xc0)) { // TP_extra_header Copy_permission_indicator == 0, unit is not encrypted return 1; } + /* handle bus encryption first */ if (aacs->bee && aacs->bec) { for (i = 0; i < ALIGNED_UNIT_LEN; i += SECTOR_LEN) { _decrypt_bus(aacs, buf + i); } } - if (_decrypt_unit(aacs, out_buf, buf, aacs->current_cps_unit)) { - memcpy(buf, out_buf, ALIGNED_UNIT_LEN); + /* decrypt in-place if current unit key is known */ + if (AACS_LIKELY(aacs->cps_unit_selected) || AACS_LIKELY(aacs->num_uks == 1)) { + if (AACS_LIKELY(_decrypt_unit(aacs, buf, NULL, aacs->current_cps_unit))) { + return 1; + } - return 1; + } else { + + /* unit key is unknown (playback without menus), try each key until right key is found */ + uint8_t out_buf[ALIGNED_UNIT_LEN]; + for (i = 0; i < aacs->num_uks; i++) { + if (_decrypt_unit(aacs, out_buf, buf, i)) { + DEBUG(DBG_AACS, "autodetected current CPS unit (%d)\n", i); + aacs->current_cps_unit = i; + aacs->cps_unit_selected = 1; + memcpy(buf, out_buf, ALIGNED_UNIT_LEN); + return 1; + } + } } DEBUG(DBG_AACS, "Failed decrypting unit [6144 bytes]\n"); - return 0; } @@ -1264,12 +1283,14 @@ void aacs_select_title(AACS *aacs, uint32_t title) if (title == 0xffff) { /* first play */ aacs->current_cps_unit = aacs->cps_units[0]; + aacs->cps_unit_selected = 0; DEBUG(DBG_AACS, "aacs_set_title(first_play): CPS unit %d\n", aacs->current_cps_unit); return; } if (title <= aacs->num_titles) { aacs->current_cps_unit = aacs->cps_units[title + 1]; + aacs->cps_unit_selected = 1; DEBUG(DBG_AACS, "aacs_set_title(%d): CPS unit %d\n", title, aacs->current_cps_unit); return; } _______________________________________________ libaacs-devel mailing list libaacs-devel@videolan.org https://mailman.videolan.org/listinfo/libaacs-devel
