Re: [Qemu-devel] [PATCH v3 13/18] crypto: cipher: add afalg-backend cipher support

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

On Sat, Apr 22, 2017 at 03:20:22PM +0800, Longpeng(Mike) wrote:
> Adds afalg-backend cipher support: introduces some private APIs
> firstly, and then intergrates them into qcrypto_cipher_afalg_driver.
> 
> Signed-off-by: Longpeng(Mike) <longpeng2@huawei.com>
> ---
>  crypto/Makefile.objs       |   1 +
>  crypto/afalgpriv.h         |   9 ++
>  crypto/cipher-afalg.c      | 229 +++++++++++++++++++++++++++++++++++++++++++++
>  crypto/cipher.c            |  28 +++++-
>  crypto/cipherpriv.h        |  11 +++
>  include/crypto/cipher.h    |   8 ++
>  tests/test-crypto-cipher.c |  10 +-
>  7 files changed, 294 insertions(+), 2 deletions(-)
>  create mode 100644 crypto/cipher-afalg.c
> 

> diff --git a/crypto/cipher-afalg.c b/crypto/cipher-afalg.c
> new file mode 100644
> index 0000000..cce8e6b
> --- /dev/null
> +++ b/crypto/cipher-afalg.c

> +static char *
> +qcrypto_afalg_cipher_format_name(QCryptoCipherAlgorithm alg,
> +                                 QCryptoCipherMode mode,
> +                                 Error **errp)
> +{
> +    char *name;
> +    const char *alg_name;
> +    const char *mode_name;
> +    int ret;
> +
> +    switch (alg) {
> +    case QCRYPTO_CIPHER_ALG_AES_128:
> +    case QCRYPTO_CIPHER_ALG_AES_192:
> +    case QCRYPTO_CIPHER_ALG_AES_256:
> +        alg_name = "aes";
> +        break;
> +    case QCRYPTO_CIPHER_ALG_CAST5_128:
> +        alg_name = "cast5";
> +        break;
> +    case QCRYPTO_CIPHER_ALG_SERPENT_128:
> +    case QCRYPTO_CIPHER_ALG_SERPENT_192:
> +    case QCRYPTO_CIPHER_ALG_SERPENT_256:
> +        alg_name = "serpent";
> +        break;
> +    case QCRYPTO_CIPHER_ALG_TWOFISH_128:
> +    case QCRYPTO_CIPHER_ALG_TWOFISH_192:
> +    case QCRYPTO_CIPHER_ALG_TWOFISH_256:
> +        alg_name = "twofish";
> +        break;
> +
> +    default:
> +        error_setg(errp, "Unsupported cipher algorithm %d", alg);
> +        return NULL;
> +    }
> +
> +    mode_name = QCryptoCipherMode_lookup[mode];
> +
> +    name = g_new0(char, SALG_NAME_LEN_MAX);
> +    ret = snprintf(name, SALG_NAME_LEN_MAX, "%s(%s)", mode_name,
> +                   alg_name);
> +    if (ret < 0 || ret >= SALG_NAME_LEN_MAX) {
> +        error_setg(errp, "Build ciphername(name='%s',mode='%s') failed",
> +                   alg_name, mode_name);
> +        g_free(name);
> +        return NULL;
> +    }

Using g_new0+snprintf() is never a good idea. Instead use  g_strdup_printf().

There is no need for the length check here either, since 
qcrypto_afalg_comm_alloc() is already going to bounds check
it


> +
> +    return name;
> +}
> +
> +QCryptoAFAlg *
> +qcrypto_afalg_cipher_ctx_new(QCryptoCipherAlgorithm alg,
> +                             QCryptoCipherMode mode,
> +                             const uint8_t *key,
> +                             size_t nkey, Error **errp)
> +{
> +    QCryptoAFAlg *afalg;
> +    size_t except_niv;

Typo - I think you meant  'expect_niv' instead - same typo in other
methods below too

> +    char *name;
> +
> +    name = qcrypto_afalg_cipher_format_name(alg, mode, errp);
> +    if (!name) {
> +        return NULL;
> +    }
> +
> +    afalg = qcrypto_afalg_comm_alloc(AFALG_TYPE_CIPHER, name, errp);
> +    if (!afalg) {
> +        g_free(name);
> +        return NULL;
> +    }
> +    afalg->name = name;
> +
> +    /* setkey */
> +    if (qemu_setsockopt(afalg->tfmfd, SOL_ALG, ALG_SET_KEY, key,
> +                        nkey) != 0) {
> +        error_setg_errno(errp, errno, "Set key failed");
> +        qcrypto_afalg_comm_free(afalg);
> +        return NULL;
> +    }
> +
> +    /* prepare msg header */
> +    afalg->msg = g_new0(struct msghdr, 1);
> +    afalg->msg->msg_controllen += CMSG_SPACE(ALG_OPTYPE_LEN);
> +    except_niv = qcrypto_cipher_get_iv_len(alg, mode);
> +    if (except_niv) {
> +        afalg->msg->msg_controllen += CMSG_SPACE(ALG_MSGIV_LEN(except_niv));
> +    }
> +    afalg->msg->msg_control = g_new0(uint8_t, afalg->msg->msg_controllen);
> +
> +    /* We use 1st msghdr for crypto-info and 2nd msghdr for IV-info */
> +    afalg->cmsg = CMSG_FIRSTHDR(afalg->msg);
> +    afalg->cmsg->cmsg_level = SOL_ALG;
> +    afalg->cmsg->cmsg_type = ALG_SET_OP;
> +    afalg->cmsg->cmsg_len = CMSG_SPACE(ALG_OPTYPE_LEN);
> +
> +    return afalg;
> +}
> +
> +static int
> +qcrypto_afalg_cipher_setiv(QCryptoCipher *cipher,
> +                           const uint8_t *iv,
> +                           size_t niv, Error **errp)
> +{
> +    struct af_alg_iv *alg_iv;
> +    size_t except_niv;
> +    QCryptoAFAlg *afalg = cipher->opaque;
> +
> +    except_niv = qcrypto_cipher_get_iv_len(cipher->alg, cipher->mode);
> +    if (niv != except_niv) {
> +        error_setg(errp, "Set IV len(%lu) not match excepted(%lu)",
> +                   niv, except_niv);

When printing variables that are 'size_t', you need '%zu' rather
than '%lu'

> +        return -1;
> +    }
> +
> +    /* move ->cmsg to next msghdr, for IV-info */
> +    afalg->cmsg = CMSG_NXTHDR(afalg->msg, afalg->cmsg);
> +
> +    /* build setiv msg */
> +    afalg->cmsg->cmsg_level = SOL_ALG;
> +    afalg->cmsg->cmsg_type = ALG_SET_IV;
> +    afalg->cmsg->cmsg_len = CMSG_SPACE(ALG_MSGIV_LEN(niv));
> +    alg_iv = (struct af_alg_iv *)CMSG_DATA(afalg->cmsg);
> +    alg_iv->ivlen = niv;
> +    memcpy(alg_iv->iv, iv, niv);
> +
> +    return 0;
> +}
> +
> +static int
> +qcrypto_afalg_cipher_op(QCryptoAFAlg *afalg,
> +                        const void *in, void *out,
> +                        size_t len, bool do_encrypt,
> +                        Error **errp)
> +{
> +    uint32_t *type = NULL;
> +    struct iovec iov;
> +    size_t ret, done = 0;
> +    uint32_t origin_contorllen;

Typo - you mean 'origin_controllen'

> +
> +    origin_contorllen = afalg->msg->msg_controllen;
> +    /* movev ->cmsg to first header, for crypto-info */
> +    afalg->cmsg = CMSG_FIRSTHDR(afalg->msg);
> +
> +    /* build encrypt msg */
> +    afalg->msg->msg_iov = &iov;
> +    afalg->msg->msg_iovlen = 1;
> +    type = (uint32_t *)CMSG_DATA(afalg->cmsg);
> +    if (do_encrypt) {
> +        *type = ALG_OP_ENCRYPT;
> +    } else {
> +        *type = ALG_OP_DECRYPT;
> +    }
> +
> +    do {
> +        iov.iov_base = (void *)in + done;
> +        iov.iov_len = len - done;
> +
> +        /* send info to AF_ALG core */
> +        ret = sendmsg(afalg->opfd, afalg->msg, 0);
> +        if (ret == -1) {
> +            error_setg_errno(errp, errno, "Send data to AF_ALG core failed");
> +            return -1;
> +        }
> +
> +        /* encrypto && get result */
> +        if (ret != read(afalg->opfd, out, ret)) {
> +            error_setg_errno(errp, errno, "Get result from AF_ALG core failed");
> +            return -1;
> +        }
> +
> +        /* do not update IV for following chunks */
> +        afalg->msg->msg_controllen = 0;
> +        done += ret;
> +    } while (done < len);
> +
> +    afalg->msg->msg_controllen = origin_contorllen;
> +
> +    return 0;
> +}


> diff --git a/crypto/cipher.c b/crypto/cipher.c
> index a6e052c..4a6f548 100644
> --- a/crypto/cipher.c
> +++ b/crypto/cipher.c
> @@ -164,17 +164,34 @@ QCryptoCipher *qcrypto_cipher_new(QCryptoCipherAlgorithm alg,
>  {
>      QCryptoCipher *cipher;
>      void *ctx;

Initialize this to NULL;

> +    Error *err2 = NULL;
> +    QCryptoCipherDriver *drv;
> +
> +#ifdef CONFIG_AF_ALG
> +    ctx = qcrypto_afalg_cipher_ctx_new(alg, mode, key, nkey, &err2);
> +    if (ctx) {
> +        drv = &qcrypto_cipher_afalg_driver;
> +        goto set_cipher;

And drop the goto here.

> +    }
> +#endif
>

And add 'if (!ctx)' before this next block:

>      ctx = qcrypto_cipher_ctx_new(alg, mode, key, nkey, errp);
>      if (ctx == NULL) {
> +        error_free(err2);
>          return NULL;
>      }
>  
> +    drv = &qcrypto_cipher_lib_driver;
> +    error_free(err2);
> +
> +#ifdef CONFIG_AF_ALG
> +set_cipher:
> +#endif
>      cipher = g_new0(QCryptoCipher, 1);
>      cipher->alg = alg;
>      cipher->mode = mode;
>      cipher->opaque = ctx;
> -    cipher->driver = (void *)&qcrypto_cipher_lib_driver;
> +    cipher->driver = (void *)drv;
>  
>      return cipher;
>  }
> @@ -220,3 +237,12 @@ void qcrypto_cipher_free(QCryptoCipher *cipher)
>          g_free(cipher);
>      }
>  }
> +
> +bool qcrypto_cipher_using_afalg_drv(QCryptoCipher *cipher)
> +{
> +#ifdef CONFIG_AF_ALG
> +    return cipher->driver == (void *)&qcrypto_cipher_afalg_driver;
> +#else
> +    return false;
> +#endif
> +}


> diff --git a/include/crypto/cipher.h b/include/crypto/cipher.h
> index 984fb82..037f602 100644
> --- a/include/crypto/cipher.h
> +++ b/include/crypto/cipher.h
> @@ -233,4 +233,12 @@ int qcrypto_cipher_setiv(QCryptoCipher *cipher,
>                           const uint8_t *iv, size_t niv,
>                           Error **errp);
>  
> +/**
> + * qcrypto_cipher_using_afalg_drv:
> + * @ the cipher object
> + *
> + * Returns: true if @cipher is using afalg driver, otherwise false.
> + */
> +bool qcrypto_cipher_using_afalg_drv(QCryptoCipher *cipher);

IMHO whether we use afalg or not should be hidden from users of the
crypto API, so I'd prefer we didn't add this method

> diff --git a/tests/test-crypto-cipher.c b/tests/test-crypto-cipher.c
> index 07fa2fa..8bb3308 100644
> --- a/tests/test-crypto-cipher.c
> +++ b/tests/test-crypto-cipher.c
> @@ -715,6 +715,7 @@ static void test_cipher_null_iv(void)
>      uint8_t key[32] = { 0 };
>      uint8_t plaintext[32] = { 0 };
>      uint8_t ciphertext[32] = { 0 };
> +    Error *err = NULL;
>  
>      cipher = qcrypto_cipher_new(
>          QCRYPTO_CIPHER_ALG_AES_256,
> @@ -729,7 +730,14 @@ static void test_cipher_null_iv(void)
>                             plaintext,
>                             ciphertext,
>                             sizeof(plaintext),
> -                           &error_abort);
> +                           &err);
> +
> +    if (qcrypto_cipher_using_afalg_drv(cipher)) {
> +        g_assert(err != NULL);
> +        error_free_or_abort(&err);
> +    } else {
> +        g_assert(err == NULL);
> +    }

This looks wierd - we should not have different behaviour here when
using afalg

Regards,
Daniel
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