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gpg: Clean up ECDH code path (5).
* g10/ecdh.c (pk_ecdh_encrypt_with_shared_point): Now, it's only for encrytion. (pk_ecdh_decrypt): Use prepare_ecdh_with_shared_point and move decrypt code path in original pk_ecdh_encrypt_with_shared_point here. * g10/pkglue.h (pk_ecdh_encrypt_with_shared_point): Change API. * g10/pkglue.c (pk_encrypt): Follow the change. Signed-off-by: NIIBE Yutaka <gniibe@fsij.org>
This commit is contained in:
NIIBE Yutaka
parent
64d93271bf
commit
510bda7d37
259
g10/ecdh.c
259
g10/ecdh.c
@ -330,15 +330,14 @@ prepare_ecdh_with_shared_point (gcry_mpi_t shared_mpi,
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return err;
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}
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/* Encrypts/decrypts DATA using a key derived from the ECC shared
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point SHARED_MPI using the FIPS SP 800-56A compliant method
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key_derivation+key_wrapping. If IS_ENCRYPT is true the function
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encrypts; if false, it decrypts. PKEY is the public key and PK_FP
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the fingerprint of this public key. On success the result is
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stored at R_RESULT; on failure NULL is stored at R_RESULT and an
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error code returned. */
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/* Encrypts DATA using a key derived from the ECC shared point
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SHARED_MPI using the FIPS SP 800-56A compliant method
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key_derivation+key_wrapping. PKEY is the public key and PK_FP the
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fingerprint of this public key. On success the result is stored at
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R_RESULT; on failure NULL is stored at R_RESULT and an error code
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returned. */
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gpg_error_t
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pk_ecdh_encrypt_with_shared_point (int is_encrypt, gcry_mpi_t shared_mpi,
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pk_ecdh_encrypt_with_shared_point (gcry_mpi_t shared_mpi,
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const byte pk_fp[MAX_FINGERPRINT_LEN],
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gcry_mpi_t data, gcry_mpi_t *pkey,
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gcry_mpi_t *r_result)
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@ -349,6 +348,7 @@ pk_ecdh_encrypt_with_shared_point (int is_encrypt, gcry_mpi_t shared_mpi,
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byte *data_buf;
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int data_buf_size;
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gcry_mpi_t result;
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byte *in;
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*r_result = NULL;
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@ -357,7 +357,7 @@ pk_ecdh_encrypt_with_shared_point (int is_encrypt, gcry_mpi_t shared_mpi,
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return err;
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data_buf_size = (gcry_mpi_get_nbits(data)+7)/8;
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if ((data_buf_size & 7) != (is_encrypt ? 0 : 1))
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if ((data_buf_size & 7) != 0)
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{
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log_error ("can't use a shared secret of %d bytes for ecdh\n",
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data_buf_size);
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@ -373,117 +373,50 @@ pk_ecdh_encrypt_with_shared_point (int is_encrypt, gcry_mpi_t shared_mpi,
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return err;
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}
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if (is_encrypt)
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in = data_buf+1+data_buf_size+8;
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/* Write data MPI into the end of data_buf. data_buf is size
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aeswrap data. */
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err = gcry_mpi_print (GCRYMPI_FMT_USG, in,
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data_buf_size, &nbytes, data/*in*/);
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if (err)
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{
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byte *in = data_buf+1+data_buf_size+8;
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/* Write data MPI into the end of data_buf. data_buf is size
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aeswrap data. */
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err = gcry_mpi_print (GCRYMPI_FMT_USG, in,
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data_buf_size, &nbytes, data/*in*/);
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if (err)
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{
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log_error ("ecdh failed to export DEK: %s\n", gpg_strerror (err));
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gcry_cipher_close (hd);
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xfree (data_buf);
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return err;
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}
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if (DBG_CRYPTO)
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log_printhex (in, data_buf_size, "ecdh encrypting :");
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err = gcry_cipher_encrypt (hd, data_buf+1, data_buf_size+8,
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in, data_buf_size);
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memset (in, 0, data_buf_size);
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log_error ("ecdh failed to export DEK: %s\n", gpg_strerror (err));
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gcry_cipher_close (hd);
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if (err)
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{
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log_error ("ecdh failed in gcry_cipher_encrypt: %s\n",
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gpg_strerror (err));
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xfree (data_buf);
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return err;
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}
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data_buf[0] = data_buf_size+8;
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if (DBG_CRYPTO)
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log_printhex (data_buf+1, data_buf[0], "ecdh encrypted to:");
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result = gcry_mpi_set_opaque (NULL, data_buf, 8 * (1+data_buf[0]));
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if (!result)
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{
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err = gpg_error_from_syserror ();
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xfree (data_buf);
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log_error ("ecdh failed to create an MPI: %s\n",
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gpg_strerror (err));
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return err;
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}
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*r_result = result;
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}
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else
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{
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byte *in;
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const void *p;
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unsigned int nbits;
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p = gcry_mpi_get_opaque (data, &nbits);
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nbytes = (nbits+7)/8;
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if (!p || nbytes > data_buf_size || !nbytes)
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{
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xfree (data_buf);
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gcry_cipher_close (hd);
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return gpg_error (GPG_ERR_BAD_MPI);
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}
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memcpy (data_buf, p, nbytes);
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if (data_buf[0] != nbytes-1)
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{
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log_error ("ecdh inconsistent size\n");
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xfree (data_buf);
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gcry_cipher_close (hd);
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return gpg_error (GPG_ERR_BAD_MPI);
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}
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in = data_buf+data_buf_size;
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data_buf_size = data_buf[0];
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if (DBG_CRYPTO)
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log_printhex (data_buf+1, data_buf_size, "ecdh decrypting :");
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err = gcry_cipher_decrypt (hd, in, data_buf_size, data_buf+1,
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data_buf_size);
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gcry_cipher_close (hd);
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if (err)
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{
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log_error ("ecdh failed in gcry_cipher_decrypt: %s\n",
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gpg_strerror (err));
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xfree (data_buf);
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return err;
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}
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data_buf_size -= 8;
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if (DBG_CRYPTO)
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log_printhex (in, data_buf_size, "ecdh decrypted to :");
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/* Padding is removed later. */
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/* if (in[data_buf_size-1] > 8 ) */
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/* { */
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/* log_error ("ecdh failed at decryption: invalid padding." */
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/* " 0x%02x > 8\n", in[data_buf_size-1] ); */
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/* return gpg_error (GPG_ERR_BAD_KEY); */
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/* } */
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err = gcry_mpi_scan (&result, GCRYMPI_FMT_USG, in, data_buf_size, NULL);
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xfree (data_buf);
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if (err)
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{
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log_error ("ecdh failed to create a plain text MPI: %s\n",
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gpg_strerror (err));
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return err;
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}
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*r_result = result;
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return err;
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}
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if (DBG_CRYPTO)
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log_printhex (in, data_buf_size, "ecdh encrypting :");
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err = gcry_cipher_encrypt (hd, data_buf+1, data_buf_size+8,
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in, data_buf_size);
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memset (in, 0, data_buf_size);
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gcry_cipher_close (hd);
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if (err)
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{
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log_error ("ecdh failed in gcry_cipher_encrypt: %s\n",
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gpg_strerror (err));
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xfree (data_buf);
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return err;
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}
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data_buf[0] = data_buf_size+8;
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if (DBG_CRYPTO)
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log_printhex (data_buf+1, data_buf[0], "ecdh encrypted to:");
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result = gcry_mpi_set_opaque (NULL, data_buf, 8 * (1+data_buf[0]));
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if (!result)
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{
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err = gpg_error_from_syserror ();
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xfree (data_buf);
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log_error ("ecdh failed to create an MPI: %s\n",
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gpg_strerror (err));
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return err;
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}
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*r_result = result;
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return err;
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}
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@ -538,12 +471,98 @@ pk_ecdh_generate_ephemeral_key (gcry_mpi_t *pkey, gcry_mpi_t *r_k)
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/* Perform ECDH decryption. */
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int
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pk_ecdh_decrypt (gcry_mpi_t * result, const byte sk_fp[MAX_FINGERPRINT_LEN],
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gcry_mpi_t data, gcry_mpi_t shared, gcry_mpi_t * skey)
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pk_ecdh_decrypt (gcry_mpi_t *r_result, const byte sk_fp[MAX_FINGERPRINT_LEN],
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gcry_mpi_t data, gcry_mpi_t shared_mpi, gcry_mpi_t * skey)
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{
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gpg_error_t err;
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gcry_cipher_hd_t hd;
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size_t nbytes;
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byte *data_buf;
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int data_buf_size;
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byte *in;
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const void *p;
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unsigned int nbits;
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if (!data)
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return gpg_error (GPG_ERR_BAD_MPI);
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return pk_ecdh_encrypt_with_shared_point (0 /*=decryption*/, shared,
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sk_fp, data/*encr data as an MPI*/,
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skey, result);
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*r_result = NULL;
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err = prepare_ecdh_with_shared_point (shared_mpi, sk_fp, skey, &hd);
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if (err)
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return err;
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data_buf_size = (gcry_mpi_get_nbits(data)+7)/8;
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if ((data_buf_size & 7) != 1)
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{
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log_error ("can't use a shared secret of %d bytes for ecdh\n",
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data_buf_size);
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gcry_cipher_close (hd);
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return gpg_error (GPG_ERR_BAD_DATA);
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}
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data_buf = xtrymalloc_secure( 1 + 2*data_buf_size + 8);
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if (!data_buf)
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{
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err = gpg_error_from_syserror ();
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gcry_cipher_close (hd);
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return err;
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}
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p = gcry_mpi_get_opaque (data, &nbits);
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nbytes = (nbits+7)/8;
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if (!p || nbytes > data_buf_size || !nbytes)
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{
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xfree (data_buf);
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gcry_cipher_close (hd);
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return gpg_error (GPG_ERR_BAD_MPI);
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}
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memcpy (data_buf, p, nbytes);
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if (data_buf[0] != nbytes-1)
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{
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log_error ("ecdh inconsistent size\n");
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xfree (data_buf);
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gcry_cipher_close (hd);
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return gpg_error (GPG_ERR_BAD_MPI);
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}
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in = data_buf+data_buf_size;
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data_buf_size = data_buf[0];
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if (DBG_CRYPTO)
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log_printhex (data_buf+1, data_buf_size, "ecdh decrypting :");
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err = gcry_cipher_decrypt (hd, in, data_buf_size, data_buf+1,
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data_buf_size);
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gcry_cipher_close (hd);
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if (err)
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{
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log_error ("ecdh failed in gcry_cipher_decrypt: %s\n",
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gpg_strerror (err));
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xfree (data_buf);
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return err;
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}
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data_buf_size -= 8;
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if (DBG_CRYPTO)
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log_printhex (in, data_buf_size, "ecdh decrypted to :");
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/* Padding is removed later. */
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/* if (in[data_buf_size-1] > 8 ) */
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/* { */
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/* log_error ("ecdh failed at decryption: invalid padding." */
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/* " 0x%02x > 8\n", in[data_buf_size-1] ); */
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/* return gpg_error (GPG_ERR_BAD_KEY); */
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/* } */
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err = gcry_mpi_scan (r_result, GCRYMPI_FMT_USG, in, data_buf_size, NULL);
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xfree (data_buf);
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if (err)
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{
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log_error ("ecdh failed to create a plain text MPI: %s\n",
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gpg_strerror (err));
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return err;
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}
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return err;
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}
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@ -330,7 +330,7 @@ pk_encrypt (pubkey_algo_t algo, gcry_mpi_t *resarr, gcry_mpi_t data,
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if (fpn != 20)
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rc = gpg_error (GPG_ERR_INV_LENGTH);
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else
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rc = pk_ecdh_encrypt_with_shared_point (1 /*=encrypton*/, shared,
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rc = pk_ecdh_encrypt_with_shared_point (shared,
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fp, data, pkey, &result);
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gcry_mpi_release (shared);
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if (!rc)
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@ -36,7 +36,7 @@ int pk_check_secret_key (pubkey_algo_t algo, gcry_mpi_t *skey);
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gcry_mpi_t pk_ecdh_default_params (unsigned int qbits);
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gpg_error_t pk_ecdh_generate_ephemeral_key (gcry_mpi_t *pkey, gcry_mpi_t *r_k);
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gpg_error_t pk_ecdh_encrypt_with_shared_point
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/* */ (int is_encrypt, gcry_mpi_t shared_mpi,
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/* */ (gcry_mpi_t shared_mpi,
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const byte pk_fp[MAX_FINGERPRINT_LEN],
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gcry_mpi_t data, gcry_mpi_t *pkey,
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gcry_mpi_t *out);
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