diff options
| -rw-r--r-- | g10/ecdh.c | 249 | ||||
| -rw-r--r-- | g10/pkglue.c | 2 | ||||
| -rw-r--r-- | g10/pkglue.h | 2 |
3 files changed, 136 insertions, 117 deletions
diff --git a/g10/ecdh.c b/g10/ecdh.c index 8f8c9a37e..dd9989bca 100644 --- a/g10/ecdh.c +++ b/g10/ecdh.c @@ -330,15 +330,14 @@ prepare_ecdh_with_shared_point (gcry_mpi_t shared_mpi, return err; } -/* Encrypts/decrypts DATA using a key derived from the ECC shared - point SHARED_MPI using the FIPS SP 800-56A compliant method - key_derivation+key_wrapping. If IS_ENCRYPT is true the function - encrypts; if false, it decrypts. PKEY is the public key and PK_FP - the fingerprint of this public key. On success the result is - stored at R_RESULT; on failure NULL is stored at R_RESULT and an - error code returned. */ +/* Encrypts DATA using a key derived from the ECC shared point + SHARED_MPI using the FIPS SP 800-56A compliant method + key_derivation+key_wrapping. PKEY is the public key and PK_FP the + fingerprint of this public key. On success the result is stored at + R_RESULT; on failure NULL is stored at R_RESULT and an error code + returned. */ gpg_error_t -pk_ecdh_encrypt_with_shared_point (int is_encrypt, gcry_mpi_t shared_mpi, +pk_ecdh_encrypt_with_shared_point (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) @@ -349,6 +348,7 @@ pk_ecdh_encrypt_with_shared_point (int is_encrypt, gcry_mpi_t shared_mpi, byte *data_buf; int data_buf_size; gcry_mpi_t result; + byte *in; *r_result = NULL; @@ -357,7 +357,7 @@ pk_ecdh_encrypt_with_shared_point (int is_encrypt, gcry_mpi_t shared_mpi, return err; data_buf_size = (gcry_mpi_get_nbits(data)+7)/8; - if ((data_buf_size & 7) != (is_encrypt ? 0 : 1)) + if ((data_buf_size & 7) != 0) { log_error ("can't use a shared secret of %d bytes for ecdh\n", data_buf_size); @@ -373,117 +373,50 @@ pk_ecdh_encrypt_with_shared_point (int is_encrypt, gcry_mpi_t shared_mpi, return err; } - 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, - data_buf_size, &nbytes, data/*in*/); - if (err) - { - log_error ("ecdh failed to export DEK: %s\n", gpg_strerror (err)); - gcry_cipher_close (hd); - xfree (data_buf); - return err; - } - - if (DBG_CRYPTO) - log_printhex (in, data_buf_size, "ecdh encrypting :"); - - err = gcry_cipher_encrypt (hd, data_buf+1, data_buf_size+8, - in, data_buf_size); - memset (in, 0, data_buf_size); - gcry_cipher_close (hd); - if (err) - { - log_error ("ecdh failed in gcry_cipher_encrypt: %s\n", - gpg_strerror (err)); - xfree (data_buf); - return err; - } - data_buf[0] = data_buf_size+8; - - if (DBG_CRYPTO) - log_printhex (data_buf+1, data_buf[0], "ecdh encrypted to:"); - - result = gcry_mpi_set_opaque (NULL, data_buf, 8 * (1+data_buf[0])); - if (!result) - { - err = gpg_error_from_syserror (); - xfree (data_buf); - log_error ("ecdh failed to create an MPI: %s\n", - gpg_strerror (err)); - return err; - } + in = data_buf+1+data_buf_size+8; - *r_result = result; - } - else + /* Write data MPI into the end of data_buf. data_buf is size + aeswrap data. */ + err = gcry_mpi_print (GCRYMPI_FMT_USG, in, + data_buf_size, &nbytes, data/*in*/); + if (err) { - byte *in; - const void *p; - unsigned int nbits; - - p = gcry_mpi_get_opaque (data, &nbits); - nbytes = (nbits+7)/8; - if (!p || nbytes > data_buf_size || !nbytes) - { - xfree (data_buf); - gcry_cipher_close (hd); - return gpg_error (GPG_ERR_BAD_MPI); - } - memcpy (data_buf, p, nbytes); - if (data_buf[0] != nbytes-1) - { - log_error ("ecdh inconsistent size\n"); - xfree (data_buf); - gcry_cipher_close (hd); - return gpg_error (GPG_ERR_BAD_MPI); - } - in = data_buf+data_buf_size; - data_buf_size = data_buf[0]; - - if (DBG_CRYPTO) - log_printhex (data_buf+1, data_buf_size, "ecdh decrypting :"); - - err = gcry_cipher_decrypt (hd, in, data_buf_size, data_buf+1, - data_buf_size); + log_error ("ecdh failed to export DEK: %s\n", gpg_strerror (err)); gcry_cipher_close (hd); - if (err) - { - log_error ("ecdh failed in gcry_cipher_decrypt: %s\n", - gpg_strerror (err)); - xfree (data_buf); - return err; - } + xfree (data_buf); + return err; + } - data_buf_size -= 8; + if (DBG_CRYPTO) + log_printhex (in, data_buf_size, "ecdh encrypting :"); - if (DBG_CRYPTO) - log_printhex (in, data_buf_size, "ecdh decrypted to :"); + err = gcry_cipher_encrypt (hd, data_buf+1, data_buf_size+8, + in, data_buf_size); + memset (in, 0, data_buf_size); + gcry_cipher_close (hd); + if (err) + { + log_error ("ecdh failed in gcry_cipher_encrypt: %s\n", + gpg_strerror (err)); + xfree (data_buf); + return err; + } + data_buf[0] = data_buf_size+8; - /* Padding is removed later. */ - /* if (in[data_buf_size-1] > 8 ) */ - /* { */ - /* log_error ("ecdh failed at decryption: invalid padding." */ - /* " 0x%02x > 8\n", in[data_buf_size-1] ); */ - /* return gpg_error (GPG_ERR_BAD_KEY); */ - /* } */ + if (DBG_CRYPTO) + log_printhex (data_buf+1, data_buf[0], "ecdh encrypted to:"); - err = gcry_mpi_scan (&result, GCRYMPI_FMT_USG, in, data_buf_size, NULL); + result = gcry_mpi_set_opaque (NULL, data_buf, 8 * (1+data_buf[0])); + if (!result) + { + err = gpg_error_from_syserror (); xfree (data_buf); - if (err) - { - log_error ("ecdh failed to create a plain text MPI: %s\n", - gpg_strerror (err)); - return err; - } - - *r_result = result; + log_error ("ecdh failed to create an MPI: %s\n", + gpg_strerror (err)); + return err; } + *r_result = result; return err; } @@ -538,12 +471,98 @@ pk_ecdh_generate_ephemeral_key (gcry_mpi_t *pkey, gcry_mpi_t *r_k) /* Perform ECDH decryption. */ int -pk_ecdh_decrypt (gcry_mpi_t * result, const byte sk_fp[MAX_FINGERPRINT_LEN], - gcry_mpi_t data, gcry_mpi_t shared, gcry_mpi_t * skey) +pk_ecdh_decrypt (gcry_mpi_t *r_result, const byte sk_fp[MAX_FINGERPRINT_LEN], + gcry_mpi_t data, gcry_mpi_t shared_mpi, gcry_mpi_t * skey) { + gpg_error_t err; + gcry_cipher_hd_t hd; + size_t nbytes; + byte *data_buf; + int data_buf_size; + byte *in; + const void *p; + unsigned int nbits; + if (!data) return gpg_error (GPG_ERR_BAD_MPI); - return pk_ecdh_encrypt_with_shared_point (0 /*=decryption*/, shared, - sk_fp, data/*encr data as an MPI*/, - skey, result); + + *r_result = NULL; + + err = prepare_ecdh_with_shared_point (shared_mpi, sk_fp, skey, &hd); + if (err) + return err; + + data_buf_size = (gcry_mpi_get_nbits(data)+7)/8; + if ((data_buf_size & 7) != 1) + { + log_error ("can't use a shared secret of %d bytes for ecdh\n", + data_buf_size); + gcry_cipher_close (hd); + return gpg_error (GPG_ERR_BAD_DATA); + } + + data_buf = xtrymalloc_secure( 1 + 2*data_buf_size + 8); + if (!data_buf) + { + err = gpg_error_from_syserror (); + gcry_cipher_close (hd); + return err; + } + + p = gcry_mpi_get_opaque (data, &nbits); + nbytes = (nbits+7)/8; + if (!p || nbytes > data_buf_size || !nbytes) + { + xfree (data_buf); + gcry_cipher_close (hd); + return gpg_error (GPG_ERR_BAD_MPI); + } + memcpy (data_buf, p, nbytes); + if (data_buf[0] != nbytes-1) + { + log_error ("ecdh inconsistent size\n"); + xfree (data_buf); + gcry_cipher_close (hd); + return gpg_error (GPG_ERR_BAD_MPI); + } + in = data_buf+data_buf_size; + data_buf_size = data_buf[0]; + + if (DBG_CRYPTO) + log_printhex (data_buf+1, data_buf_size, "ecdh decrypting :"); + + err = gcry_cipher_decrypt (hd, in, data_buf_size, data_buf+1, + data_buf_size); + gcry_cipher_close (hd); + if (err) + { + log_error ("ecdh failed in gcry_cipher_decrypt: %s\n", + gpg_strerror (err)); + xfree (data_buf); + return err; + } + + data_buf_size -= 8; + + if (DBG_CRYPTO) + log_printhex (in, data_buf_size, "ecdh decrypted to :"); + + /* Padding is removed later. */ + /* if (in[data_buf_size-1] > 8 ) */ + /* { */ + /* log_error ("ecdh failed at decryption: invalid padding." */ + /* " 0x%02x > 8\n", in[data_buf_size-1] ); */ + /* return gpg_error (GPG_ERR_BAD_KEY); */ + /* } */ + + err = gcry_mpi_scan (r_result, GCRYMPI_FMT_USG, in, data_buf_size, NULL); + xfree (data_buf); + if (err) + { + log_error ("ecdh failed to create a plain text MPI: %s\n", + gpg_strerror (err)); + return err; + } + + return err; } diff --git a/g10/pkglue.c b/g10/pkglue.c index 8021a94db..d266fef61 100644 --- a/g10/pkglue.c +++ b/g10/pkglue.c @@ -330,7 +330,7 @@ pk_encrypt (pubkey_algo_t algo, gcry_mpi_t *resarr, gcry_mpi_t data, if (fpn != 20) rc = gpg_error (GPG_ERR_INV_LENGTH); else - rc = pk_ecdh_encrypt_with_shared_point (1 /*=encrypton*/, shared, + rc = pk_ecdh_encrypt_with_shared_point (shared, fp, data, pkey, &result); gcry_mpi_release (shared); if (!rc) diff --git a/g10/pkglue.h b/g10/pkglue.h index 77a380191..57a963353 100644 --- a/g10/pkglue.h +++ b/g10/pkglue.h @@ -36,7 +36,7 @@ int pk_check_secret_key (pubkey_algo_t algo, gcry_mpi_t *skey); gcry_mpi_t pk_ecdh_default_params (unsigned int qbits); gpg_error_t pk_ecdh_generate_ephemeral_key (gcry_mpi_t *pkey, gcry_mpi_t *r_k); gpg_error_t pk_ecdh_encrypt_with_shared_point -/* */ (int is_encrypt, gcry_mpi_t shared_mpi, +/* */ (gcry_mpi_t shared_mpi, const byte pk_fp[MAX_FINGERPRINT_LEN], gcry_mpi_t data, gcry_mpi_t *pkey, gcry_mpi_t *out); 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