libaacs | branch: refs/tags/0.3.0 | npzacs <[email protected]> | Sat Sep 24 16:35:46 2011 +0300| [b5e510d342362d51f14c5ac6fd6c9f79c5ce7af2] | committer: npzacs
Fixed crypto_aacs_sign(). Sometimes gcry_sexp_nth_string() returns more than 20 bytes (data prefixed with 0). This results returning invalid signature. > http://git.videolan.org/gitweb.cgi/libaacs.git/?a=commit;h=b5e510d342362d51f14c5ac6fd6c9f79c5ce7af2 --- src/libaacs/crypto.c | 17 ++++++++--------- 1 file changed, 8 insertions(+), 9 deletions(-) diff --git a/src/libaacs/crypto.c b/src/libaacs/crypto.c index 247ba51..0375c21 100644 --- a/src/libaacs/crypto.c +++ b/src/libaacs/crypto.c @@ -349,7 +349,8 @@ void crypto_aacs_sign(const uint8_t *cert, const uint8_t *priv_key, uint8_t *sig const uint8_t *nonce, const uint8_t *point) { gcry_sexp_t sexp_key = NULL, sexp_data = NULL, sexp_sig = NULL, sexp_r = NULL, sexp_s = NULL; - unsigned char block[60], *r = NULL, *s = NULL; + gcry_mpi_t mpi_r = NULL, mpi_s = NULL; + unsigned char block[60]; gcry_error_t err; GCRY_VERIFY("_aacs_sexp_key", @@ -389,13 +390,11 @@ void crypto_aacs_sign(const uint8_t *cert, const uint8_t *priv_key, uint8_t *sig gcry_sexp_dump(sexp_s); } - /* Convert the data for 'r' and 's' into unsigned char form */ - r = (unsigned char*)gcry_sexp_nth_string(sexp_r, 1); - s = (unsigned char*)gcry_sexp_nth_string(sexp_s, 1); - /* Finally concatenate 'r' and 's' to get the ECDSA signature */ - memcpy(signature, r, 20); - memcpy(signature + 20, s, 20); + mpi_r = gcry_sexp_nth_mpi (sexp_r, 1, GCRYMPI_FMT_USG); + mpi_s = gcry_sexp_nth_mpi (sexp_s, 1, GCRYMPI_FMT_USG); + gcry_mpi_print (GCRYMPI_FMT_USG, signature, 20, NULL, mpi_r); + gcry_mpi_print (GCRYMPI_FMT_USG, signature + 20, 20, NULL, mpi_s); error: @@ -405,8 +404,8 @@ void crypto_aacs_sign(const uint8_t *cert, const uint8_t *priv_key, uint8_t *sig gcry_sexp_release(sexp_sig); gcry_sexp_release(sexp_r); gcry_sexp_release(sexp_s); - gcry_free(r); - gcry_free(s); + gcry_mpi_release(mpi_r); + gcry_mpi_release(mpi_s); } static int _aacs_verify(const uint8_t *signature, _______________________________________________ libaacs-devel mailing list [email protected] http://mailman.videolan.org/listinfo/libaacs-devel
