libaacs | branch: master | npzacs <npz...@gmail.com> | Mon Jan 5 16:52:17 2015 +0200| [0235dc59448234d05d88af755383593ed1b02084] | committer: npzacs
Simplify _verify_ts() Only complete blocks can be decrypted. Block is always exactly 32 packets. Reset encryption indicator in header while checking sync bytes. > http://git.videolan.org/gitweb.cgi/libaacs.git/?a=commit;h=0235dc59448234d05d88af755383593ed1b02084 --- src/libaacs/aacs.c | 48 ++++++++++++++---------------------------------- 1 file changed, 14 insertions(+), 34 deletions(-) diff --git a/src/libaacs/aacs.c b/src/libaacs/aacs.c index 2307155..a866a92 100644 --- a/src/libaacs/aacs.c +++ b/src/libaacs/aacs.c @@ -44,6 +44,10 @@ #include <gcrypt.h> +#define SECTOR_LEN 2048 /* bus encryption block size */ +#define ALIGNED_UNIT_LEN 6144 /* aacs block size */ + + struct aacs { /* current disc */ char *path; @@ -856,38 +860,20 @@ static int _get_bus_encryption_capable(const char *path) return bec; } -static int _verify_ts(uint8_t *buf, size_t size) +static int _verify_ts(uint8_t *buf) { - uint8_t *ptr; - - if (size < 192) { - return 1; - } - - for (ptr=buf; ptr < buf+192; ptr++) { - int failed = 0; - if (*ptr == 0x47) { - uint8_t *ptr2; - - for (ptr2=ptr; ptr2 < buf + size; ptr2 += 192) { - if (*ptr2 != 0x47) { - failed = 1; - break; - } - } - if (!failed) { - return 1; - } + int i; + for (i = 0; i < ALIGNED_UNIT_LEN; i += 192) { + if (AACS_UNLIKELY(buf[i + 4] != 0x47)) { + return 0; } - ptr++; - } - - DEBUG(DBG_AACS, "Failed to verify TS!\n"); - return 0; + /* Clear copy_permission_indicator bits */ + buf[i] &= ~0xc0; + } + return 1; } -#define ALIGNED_UNIT_LEN 6144 static int _decrypt_unit(AACS *aacs, uint8_t *out_buf, const uint8_t *in_buf, uint32_t curr_uk) { gcry_cipher_hd_t gcry_h; @@ -911,7 +897,7 @@ static int _decrypt_unit(AACS *aacs, uint8_t *out_buf, const uint8_t *in_buf, ui gcry_cipher_decrypt(gcry_h, out_buf + 16, ALIGNED_UNIT_LEN - 16, in_buf + 16, ALIGNED_UNIT_LEN - 16); gcry_cipher_close(gcry_h); - if (_verify_ts(out_buf, ALIGNED_UNIT_LEN)) { + if (_verify_ts(out_buf)) { return 1; } @@ -922,7 +908,6 @@ static int _decrypt_unit(AACS *aacs, uint8_t *out_buf, const uint8_t *in_buf, ui return 0; } -#define SECTOR_LEN 2048 static void _decrypt_bus(AACS *aacs, uint8_t *buf) { gcry_cipher_hd_t gcry_h; @@ -1049,11 +1034,6 @@ int aacs_decrypt_unit(AACS *aacs, uint8_t *buf) if (_decrypt_unit(aacs, out_buf, buf, aacs->current_cps_unit)) { memcpy(buf, out_buf, ALIGNED_UNIT_LEN); - // Clear copy_permission_indicator bits - for (i = 0; i < 6144; i += 192) { - buf[i] &= ~0xc0; - } - return 1; } _______________________________________________ libaacs-devel mailing list libaacs-devel@videolan.org https://mailman.videolan.org/listinfo/libaacs-devel
