diff options
Diffstat (limited to 'g10/ecdh.c')
| -rw-r--r-- | g10/ecdh.c | 81 |
1 files changed, 39 insertions, 42 deletions
diff --git a/g10/ecdh.c b/g10/ecdh.c index 09ab3ed16..f97667ae3 100644 --- a/g10/ecdh.c +++ b/g10/ecdh.c @@ -36,7 +36,7 @@ static const struct unsigned int qbits; int openpgp_hash_id; /* KEK digest algorithm. */ int openpgp_cipher_id; /* KEK cipher algorithm. */ -} kek_params_table[] = +} kek_params_table[] = /* Note: Must be sorted by ascending values for QBITS. */ { { 256, DIGEST_ALGO_SHA256, CIPHER_ALGO_AES }, @@ -60,8 +60,8 @@ pk_ecdh_default_params (unsigned int qbits) if (!kek_params) return NULL; kek_params[0] = 3; /* Number of bytes to follow. */ - kek_params[1] = 1; /* Version for KDF+AESWRAP. */ - + kek_params[1] = 1; /* Version for KDF+AESWRAP. */ + /* Search for matching KEK parameter. Defaults to the strongest possible choices. Performance is not an issue here, only interoperability. */ @@ -78,7 +78,7 @@ pk_ecdh_default_params (unsigned int qbits) assert (i < DIM (kek_params_table)); if (DBG_CIPHER) log_printhex ("ECDH KEK params are", kek_params, sizeof(kek_params) ); - + return gcry_mpi_set_opaque (NULL, kek_params, 4 * 8); } @@ -88,16 +88,16 @@ pk_ecdh_default_params (unsigned int qbits) key_derivation+key_wrapping. If IS_ENCRYPT is true the function encrypts; if false, it decrypts. On success the result is stored at R_RESULT; on failure NULL is stored at R_RESULT and an error - code returned. + code returned. FIXME: explain PKEY and PK_FP. */ - + /* TODO: memory leaks (x_secret). */ gpg_error_t -pk_ecdh_encrypt_with_shared_point (int is_encrypt, gcry_mpi_t shared_mpi, +pk_ecdh_encrypt_with_shared_point (int is_encrypt, gcry_mpi_t shared_mpi, const byte pk_fp[MAX_FINGERPRINT_LEN], gcry_mpi_t data, gcry_mpi_t *pkey, gcry_mpi_t *r_result) @@ -106,8 +106,8 @@ pk_ecdh_encrypt_with_shared_point (int is_encrypt, gcry_mpi_t shared_mpi, byte *secret_x; int secret_x_size; unsigned int nbits; - const unsigned char *kdf_params; - size_t kdf_params_size; + const unsigned char *kek_params; + size_t kek_params_size; int kdf_hash_algo; int kdf_encr_algo; unsigned char message[256]; @@ -139,11 +139,11 @@ pk_ecdh_encrypt_with_shared_point (int is_encrypt, gcry_mpi_t shared_mpi, return err; } - secret_x_size = (nbits+7)/8; + secret_x_size = (nbits+7)/8; assert (nbytes > secret_x_size); memmove (secret_x, secret_x+1, secret_x_size); memset (secret_x+secret_x_size, 0, nbytes-secret_x_size); - + if (DBG_CIPHER) log_printhex ("ECDH shared secret X is:", secret_x, secret_x_size ); } @@ -158,24 +158,24 @@ pk_ecdh_encrypt_with_shared_point (int is_encrypt, gcry_mpi_t shared_mpi, */ if (!gcry_mpi_get_flag (pkey[2], GCRYMPI_FLAG_OPAQUE)) return GPG_ERR_BUG; - kdf_params = gcry_mpi_get_opaque (pkey[2], &nbits); - kdf_params_size = (nbits+7)/8; - + kek_params = gcry_mpi_get_opaque (pkey[2], &nbits); + kek_params_size = (nbits+7)/8; + if (DBG_CIPHER) - log_printhex ("ecdh KDF params:", kdf_params, kdf_params_size); - + log_printhex ("ecdh KDF params:", kek_params, kek_params_size); + /* Expect 4 bytes 03 01 hash_alg symm_alg. */ - if (kdf_params_size != 4 || kdf_params[0] != 3 || kdf_params[1] != 1) + if (kek_params_size != 4 || kek_params[0] != 3 || kek_params[1] != 1) return GPG_ERR_BAD_PUBKEY; - - kdf_hash_algo = kdf_params[2]; - kdf_encr_algo = kdf_params[3]; - + + kdf_hash_algo = kek_params[2]; + kdf_encr_algo = kek_params[3]; + if (DBG_CIPHER) log_debug ("ecdh KDF algorithms %s+%s with aeswrap\n", openpgp_md_algo_name (kdf_hash_algo), openpgp_cipher_algo_name (kdf_encr_algo)); - + if (kdf_hash_algo != GCRY_MD_SHA256 && kdf_hash_algo != GCRY_MD_SHA384 && kdf_hash_algo != GCRY_MD_SHA512) @@ -199,7 +199,7 @@ pk_ecdh_encrypt_with_shared_point (int is_encrypt, gcry_mpi_t shared_mpi, /* fixed-length field 4 */ iobuf_write (obuf, "Anonymous Sender ", 20); /* fixed-length field 5, recipient fp */ - iobuf_write (obuf, pk_fp, 20); + iobuf_write (obuf, pk_fp, 20); message_size = iobuf_temp_to_buffer (obuf, message, sizeof message); iobuf_close (obuf); @@ -207,11 +207,10 @@ pk_ecdh_encrypt_with_shared_point (int is_encrypt, gcry_mpi_t shared_mpi, return err; if(DBG_CIPHER) - log_printhex ("ecdh KDF message params are:", - kdf_params, kdf_params_size ); + log_printhex ("ecdh KDF message params are:", message, message_size); } - /* Derive a KEK (key wrapping key) using kdf_params and secret_x. */ + /* Derive a KEK (key wrapping key) using MESSAGE and SECRET_X. */ { gcry_md_hd_t h; int old_size; @@ -222,7 +221,7 @@ pk_ecdh_encrypt_with_shared_point (int is_encrypt, gcry_mpi_t shared_mpi, kdf_hash_algo, gpg_strerror (err)); gcry_md_write(h, "\x00\x00\x00\x01", 4); /* counter = 1 */ gcry_md_write(h, secret_x, secret_x_size); /* x of the point X */ - gcry_md_write(h, kdf_params, kdf_params_size);/* KDF parameters */ + gcry_md_write(h, message, message_size);/* KDF parameters */ gcry_md_final (h); @@ -242,7 +241,7 @@ pk_ecdh_encrypt_with_shared_point (int is_encrypt, gcry_mpi_t shared_mpi, if (DBG_CIPHER) log_printhex ("ecdh KEK is:", secret_x, secret_x_size ); } - + /* And, finally, aeswrap with key secret_x. */ { gcry_cipher_hd_t hd; @@ -284,7 +283,7 @@ pk_ecdh_encrypt_with_shared_point (int is_encrypt, gcry_mpi_t shared_mpi, if (is_encrypt) { byte *in = data_buf+1+data_buf_size+8; - + /* Write data MPI into the end of data_buf. data_buf is size aeswrap data. */ err = gcry_mpi_print (GCRYMPI_FMT_USG, in, @@ -296,7 +295,7 @@ pk_ecdh_encrypt_with_shared_point (int is_encrypt, gcry_mpi_t shared_mpi, xfree (data_buf); return err; } - + if (DBG_CIPHER) log_printhex ("ecdh encrypting :", in, data_buf_size ); @@ -325,14 +324,14 @@ pk_ecdh_encrypt_with_shared_point (int is_encrypt, gcry_mpi_t shared_mpi, gpg_strerror (err)); return err; } - + *r_result = result; } else { byte *in; const void *p; - + p = gcry_mpi_get_opaque (data, &nbits); nbytes = (nbits+7)/8; if (!p || nbytes > data_buf_size || !nbytes) @@ -349,10 +348,10 @@ pk_ecdh_encrypt_with_shared_point (int is_encrypt, gcry_mpi_t shared_mpi, } in = data_buf+data_buf_size; data_buf_size = data_buf[0]; - + if (DBG_CIPHER) log_printhex ("ecdh decrypting :", data_buf+1, data_buf_size); - + err = gcry_cipher_decrypt (hd, in, data_buf_size, data_buf+1, data_buf_size); gcry_cipher_close (hd); @@ -363,12 +362,12 @@ pk_ecdh_encrypt_with_shared_point (int is_encrypt, gcry_mpi_t shared_mpi, xfree (data_buf); return err; } - + data_buf_size -= 8; - + if (DBG_CIPHER) log_printhex ("ecdh decrypted to :", in, data_buf_size); - + /* Padding is removed later. */ /* if (in[data_buf_size-1] > 8 ) */ /* { */ @@ -376,7 +375,7 @@ pk_ecdh_encrypt_with_shared_point (int is_encrypt, gcry_mpi_t shared_mpi, /* in[data_buf_size-1] ); */ /* return GPG_ERR_BAD_KEY; */ /* } */ - + err = gcry_mpi_scan (&result, GCRYMPI_FMT_USG, in, data_buf_size, NULL); xfree (data_buf); if (err) @@ -385,11 +384,11 @@ pk_ecdh_encrypt_with_shared_point (int is_encrypt, gcry_mpi_t shared_mpi, gpg_strerror (err)); return err; } - + *r_result = result; } } - + return err; } @@ -453,5 +452,3 @@ pk_ecdh_decrypt (gcry_mpi_t * result, const byte sk_fp[MAX_FINGERPRINT_LEN], sk_fp, data/*encr data as an MPI*/, skey, result); } - - |