Re: [PATCH v4 3/8] crypto: Introduce akcipher crypto class

["Daniel P. Berrangé" <berrange@redhat.com>]

On Mon, Apr 11, 2022 at 06:43:22PM +0800, zhenwei pi wrote:
> Support basic asymmetric operations: encrypt, decrypt, sign and
> verify.
> 
> Co-developed-by: lei he <helei.sig11@bytedance.com>
> Signed-off-by: lei he <helei.sig11@bytedance.com>
> Signed-off-by: zhenwei pi <pizhenwei@bytedance.com>
> ---
>  crypto/akcipher.c         | 102 +++++++++++++++++++++++++
>  crypto/akcipherpriv.h     |  43 +++++++++++
>  crypto/meson.build        |   1 +
>  include/crypto/akcipher.h | 151 ++++++++++++++++++++++++++++++++++++++
>  4 files changed, 297 insertions(+)
>  create mode 100644 crypto/akcipher.c
>  create mode 100644 crypto/akcipherpriv.h
>  create mode 100644 include/crypto/akcipher.h


> diff --git a/crypto/akcipherpriv.h b/crypto/akcipherpriv.h
> new file mode 100644
> index 0000000000..da9e54a796
> --- /dev/null
> +++ b/crypto/akcipherpriv.h
> @@ -0,0 +1,43 @@
> +/*
> + * QEMU Crypto asymmetric algorithms
> + *
> + * Copyright (c) 2022 Bytedance
> + * Author: zhenwei pi <pizhenwei@bytedance.com>
> + *
> + * This library is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU Lesser General Public
> + * License as published by the Free Software Foundation; either
> + * version 2.1 of the License, or (at your option) any later version.
> + *
> + * This library is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> + * Lesser General Public License for more details.
> + *
> + * You should have received a copy of the GNU Lesser General Public
> + * License along with this library; if not, see <http://www.gnu.org/licenses/>.
> + *
> + */
> +
> +#ifndef QCRYPTO_AKCIPHERPRIV_H
> +#define QCRYPTO_AKCIPHERPRIV_H
> +
> +#include "qapi/qapi-types-crypto.h"
> +
> +struct QCryptoAkCipherDriver {
> +    int (*encrypt)(QCryptoAkCipher *akcipher,
> +                   const void *in, size_t in_len,
> +                   void *out, size_t out_len, Error **errp);
> +    int (*decrypt)(QCryptoAkCipher *akcipher,
> +                   const void *out, size_t out_len,
> +                   void *in, size_t in_len, Error **errp);
> +    int (*sign)(QCryptoAkCipher *akcipher,
> +                const void *in, size_t in_len,
> +                void *out, size_t out_len, Error **errp);
> +    int (*verify)(QCryptoAkCipher *akcipher,
> +                  const void *in, size_t in_len,
> +                  const void *in2, size_t in2_len, Error **errp);
> +    int (*free)(QCryptoAkCipher *akcipher, Error **errp);
> +};
> +
> +#endif /* QCRYPTO_AKCIPHER_H */


> diff --git a/include/crypto/akcipher.h b/include/crypto/akcipher.h
> new file mode 100644
> index 0000000000..c1970b3b3b
> --- /dev/null
> +++ b/include/crypto/akcipher.h
> @@ -0,0 +1,151 @@
> +/*
> + * QEMU Crypto asymmetric algorithms
> + *
> + * Copyright (c) 2022 Bytedance
> + * Author: zhenwei pi <pizhenwei@bytedance.com>
> + *
> + * This library is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU Lesser General Public
> + * License as published by the Free Software Foundation; either
> + * version 2.1 of the License, or (at your option) any later version.
> + *
> + * This library is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> + * Lesser General Public License for more details.
> + *
> + * You should have received a copy of the GNU Lesser General Public
> + * License along with this library; if not, see <http://www.gnu.org/licenses/>.
> + *
> + */
> +
> +#ifndef QCRYPTO_AKCIPHER_H
> +#define QCRYPTO_AKCIPHER_H
> +
> +#include "qapi/qapi-types-crypto.h"
> +
> +typedef struct QCryptoAkCipher QCryptoAkCipher;

This belongs here.

> +typedef struct QCryptoAkCipherDriver QCryptoAkCipherDriver;

This and...

> +
> +struct QCryptoAkCipher {
> +    QCryptoAkCipherAlgorithm alg;
> +    QCryptoAkCipherKeyType type;
> +    int max_plaintext_len;
> +    int max_ciphertext_len;
> +    int max_signature_len;
> +    int max_dgst_len;
> +    QCryptoAkCipherDriver *driver;
> +};

...this should be in the akcipherpriv.h file though, since
they're only for internal usage.



> +/**
> + * qcrypto_akcipher_encrypt:
> + * @akcipher: akcipher context
> + * @in: plaintext pending to be encrypted
> + * @in_len: length of the plaintext, MUST less or equal to max_plaintext_len
> + * @out: buffer to store the ciphertext
> + * @out_len: the length of ciphertext buffer, usually equals to
> + *           max_ciphertext_len
> + * @errp: error pointer
> + *
> + * Encrypt data and write ciphertext into out
> + *
> + * Returns: length of ciphertext if encrypt succeed, otherwise -1 is returned
> + */
> +int qcrypto_akcipher_encrypt(QCryptoAkCipher *akcipher,
> +                             const void *in, size_t in_len,
> +                             void *out, size_t out_len, Error **errp);
> +
> +/**
> + * qcrypto_akcipher_decrypt:
> + * @akcipher: akcipher context
> + * @in: ciphertext to be decrypted
> + * @in_len: the length of ciphertext
> + * @out: buffer to store the plaintext
> + * @out_len: length of the plaintext buffer, usually less or equals to
> + *           max_plaintext_len

This field should be private, so we need to point people to the
methods instead. Rather than making this line so long...

> + * @errp: error pointer
> + *
> + * Decrypt ciphertext and write plaintext into out

...put here

  "@out_len should be less or equal to the size reported
   by a call to qcrypto_akcipher_max_plaintext_len()'

The same for other places where you mention limits.

> + *
> + * Returns: length of plaintext if decrypt succeed, otherwise -1 is returned
> + */
> +int qcrypto_akcipher_decrypt(QCryptoAkCipher *akcipher,
> +                             const void *in, size_t in_len,
> +                             void *out, size_t out_len, Error **errp);
> +
> +/**
> + * qcrypto_akcipher_sign:
> + * @akcipher: akcipher context
> + * @in: data to be signed
> + * @in_len: the length of data
> + * @out: buffer to store the signature
> + * @out_len: length of the signature buffer, usually equals to max_signature_len
> + * @errp: error pointer
> + *
> + * Generate signature for data using akcipher
> + *
> + * Returns: length of signature if succeed, otherwise -1 is returned
> + */
> +int qcrypto_akcipher_sign(QCryptoAkCipher *akcipher,
> +                          const void *in, size_t in_len,
> +                          void *out, size_t out_len, Error **errp);
> +
> +/**
> + * qcrypto_akcipher_verify:
> + * @akcipher: akcipher used to do verifycation
> + * @in: pointer to the signature
> + * @in_len: length of the signature
> + * @in2: pointer to original data
> + * @in2_len: the length of original data
> + * @errp: error pointer
> + *
> + * Verify the signature and the data match or not
> + *
> + * Returns: 0 for succeed, otherwise -1 is returned
> + */
> +int qcrypto_akcipher_verify(QCryptoAkCipher *akcipher,
> +                            const void *in, size_t in_len,
> +                            const void *in2, size_t in2_len, Error **errp);
> +
> +int qcrypto_akcipher_max_plaintext_len(QCryptoAkCipher *akcipher);
> +
> +int qcrypto_akcipher_max_ciphertext_len(QCryptoAkCipher *akcipher);
> +
> +int qcrypto_akcipher_max_signature_len(QCryptoAkCipher *akcipher);
> +
> +int qcrypto_akcipher_max_dgst_len(QCryptoAkCipher *akcipher);
> +
> +int qcrypto_akcipher_free(QCryptoAkCipher *akcipher, Error **errp);

Add in

G_DEFINE_AUTOPTR_CLEANUP_FUNC(QCryptoAkCipher, qcrypto_akcipher_free)


This allows users to do

   g_autoptr(QCryptoAkCIpher) cipher = qcrypto_akcipher_new(...)


and get automatic free'ing when exiting the scope.

> +
> +
> +#endif /* QCRYPTO_AKCIPHER_H */
> -- 
> 2.20.1
> 

With regards,
Daniel
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