Re: [Qemu-devel] [PULL v3 02/13] crypto: add support for PBKDF2 algorithm

[Wen Congyang <wency@cn.fujitsu.com>]

On 03/18/2016 12:53 AM, Daniel P. Berrange wrote:
> The LUKS data format includes use of PBKDF2 (Password-Based
> Key Derivation Function). The Nettle library can provide
> an implementation of this, but we don't want code directly
> depending on a specific crypto library backend. Introduce
> a new include/crypto/pbkdf.h header which defines a QEMU
> API for invoking PBKDK2. The initial implementations are
> backed by nettle & gcrypt, which are commonly available
> with distros shipping GNUTLS.
> 
> The test suite data is taken from the cryptsetup codebase
> under the LGPLv2.1+ license. This merely aims to verify
> that whatever backend we provide for this function in QEMU
> will comply with the spec.
> 
> Reviewed-by: Fam Zheng <famz@redhat.com>
> Reviewed-by: Eric Blake <eblake@redhat.com>
> Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
> ---
>  configure                 |  18 +++
>  crypto/Makefile.objs      |   4 +
>  crypto/pbkdf-gcrypt.c     |  68 ++++++++
>  crypto/pbkdf-nettle.c     |  65 ++++++++
>  crypto/pbkdf-stub.c       |  42 +++++
>  crypto/pbkdf.c            | 109 +++++++++++++
>  include/crypto/pbkdf.h    | 152 ++++++++++++++++++
>  tests/.gitignore          |   1 +
>  tests/Makefile            |   2 +
>  tests/test-crypto-pbkdf.c | 392 ++++++++++++++++++++++++++++++++++++++++++++++
>  10 files changed, 853 insertions(+)
>  create mode 100644 crypto/pbkdf-gcrypt.c
>  create mode 100644 crypto/pbkdf-nettle.c
>  create mode 100644 crypto/pbkdf-stub.c
>  create mode 100644 crypto/pbkdf.c
>  create mode 100644 include/crypto/pbkdf.h
>  create mode 100644 tests/test-crypto-pbkdf.c
> 
> diff --git a/configure b/configure
> index 71c1e2b..b88d0db 100755
> --- a/configure
> +++ b/configure
> @@ -309,6 +309,7 @@ gnutls_hash=""
>  gnutls_rnd=""
>  nettle=""
>  gcrypt=""
> +gcrypt_kdf="no"
>  vte=""
>  virglrenderer=""
>  tpm="yes"
> @@ -2302,6 +2303,19 @@ if test "$gcrypt" != "no"; then
>          if test -z "$nettle"; then
>             nettle="no"
>          fi
> +
> +        cat > $TMPC << EOF
> +#include <gcrypt.h>
> +int main(void) {
> +  gcry_kdf_derive(NULL, 0, GCRY_KDF_PBKDF2,
> +                  GCRY_MD_SHA256,
> +                  NULL, 0, 0, 0, NULL);
> + return 0;
> +}
> +EOF
> +        if compile_prog "$gcrypt_cflags" "$gcrypt_libs" ; then
> +            gcrypt_kdf=yes
> +        fi
>      else
>          if test "$gcrypt" = "yes"; then
>              feature_not_found "gcrypt" "Install gcrypt devel"
> @@ -4726,6 +4740,7 @@ echo "GNUTLS support    $gnutls"
>  echo "GNUTLS hash       $gnutls_hash"
>  echo "GNUTLS rnd        $gnutls_rnd"
>  echo "libgcrypt         $gcrypt"
> +echo "libgcrypt kdf     $gcrypt_kdf"
>  if test "$nettle" = "yes"; then
>      echo "nettle            $nettle ($nettle_version)"
>  else
> @@ -5108,6 +5123,9 @@ if test "$gnutls_rnd" = "yes" ; then
>  fi
>  if test "$gcrypt" = "yes" ; then
>    echo "CONFIG_GCRYPT=y" >> $config_host_mak
> +  if test "$gcrypt_kdf" = "yes" ; then
> +    echo "CONFIG_GCRYPT_KDF=y" >> $config_host_mak
> +  fi
>  fi
>  if test "$nettle" = "yes" ; then
>    echo "CONFIG_NETTLE=y" >> $config_host_mak
> diff --git a/crypto/Makefile.objs b/crypto/Makefile.objs
> index 967418c..7122cc8 100644
> --- a/crypto/Makefile.objs
> +++ b/crypto/Makefile.objs
> @@ -10,8 +10,12 @@ crypto-obj-y += tlssession.o
>  crypto-obj-y += secret.o
>  crypto-obj-$(CONFIG_GCRYPT) += random-gcrypt.o
>  crypto-obj-$(if $(CONFIG_GCRYPT),n,$(CONFIG_GNUTLS_RND)) += random-gnutls.o
> +crypto-obj-y += pbkdf.o
> +crypto-obj-$(CONFIG_NETTLE) += pbkdf-nettle.o
> +crypto-obj-$(if $(CONFIG_NETTLE),n,$(CONFIG_GCRYPT_KDF)) += pbkdf-gcrypt.o
>  
>  # Let the userspace emulators avoid linking gnutls/etc
>  crypto-aes-obj-y = aes.o
>  
>  stub-obj-y += random-stub.o
> +stub-obj-y += pbkdf-stub.o
> diff --git a/crypto/pbkdf-gcrypt.c b/crypto/pbkdf-gcrypt.c
> new file mode 100644
> index 0000000..885614d
> --- /dev/null
> +++ b/crypto/pbkdf-gcrypt.c
> @@ -0,0 +1,68 @@
> +/*
> + * QEMU Crypto PBKDF support (Password-Based Key Derivation Function)
> + *
> + * Copyright (c) 2015-2016 Red Hat, Inc.
> + *
> + * 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 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/>.
> + *
> + */
> +
> +#include "qemu/osdep.h"
> +#include "crypto/pbkdf.h"
> +#include "gcrypt.h"
> +
> +bool qcrypto_pbkdf2_supports(QCryptoHashAlgorithm hash)
> +{
> +    switch (hash) {
> +    case QCRYPTO_HASH_ALG_MD5:
> +    case QCRYPTO_HASH_ALG_SHA1:
> +    case QCRYPTO_HASH_ALG_SHA256:
> +        return true;
> +    default:
> +        return false;
> +    }
> +}
> +
> +int qcrypto_pbkdf2(QCryptoHashAlgorithm hash,
> +                   const uint8_t *key, size_t nkey,
> +                   const uint8_t *salt, size_t nsalt,
> +                   unsigned int iterations,
> +                   uint8_t *out, size_t nout,
> +                   Error **errp)
> +{
> +    static const int hash_map[QCRYPTO_HASH_ALG__MAX] = {
> +        [QCRYPTO_HASH_ALG_MD5] = GCRY_MD_MD5,
> +        [QCRYPTO_HASH_ALG_SHA1] = GCRY_MD_SHA1,
> +        [QCRYPTO_HASH_ALG_SHA256] = GCRY_MD_SHA256,
> +    };
> +    int ret;
> +
> +    if (hash >= G_N_ELEMENTS(hash_map) ||
> +        hash_map[hash] == GCRY_MD_NONE) {
> +        error_setg(errp, "Unexpected hash algorithm %d", hash);
> +        return -1;
> +    }
> +
> +    ret = gcry_kdf_derive(key, nkey, GCRY_KDF_PBKDF2,
> +                          hash_map[hash],
> +                          salt, nsalt, iterations,
> +                          nout, out);
> +    if (ret != 0) {
> +        error_setg(errp, "Cannot derive password: %s",
> +                   gcry_strerror(ret));
> +        return -1;
> +    }
> +
> +    return 0;
> +}
> diff --git a/crypto/pbkdf-nettle.c b/crypto/pbkdf-nettle.c
> new file mode 100644
> index 0000000..1aa7395
> --- /dev/null
> +++ b/crypto/pbkdf-nettle.c
> @@ -0,0 +1,65 @@
> +/*
> + * QEMU Crypto PBKDF support (Password-Based Key Derivation Function)
> + *
> + * Copyright (c) 2015-2016 Red Hat, Inc.
> + *
> + * 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 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/>.
> + *
> + */
> +
> +#include "qemu/osdep.h"
> +#include "crypto/pbkdf.h"
> +#include "nettle/pbkdf2.h"

I get the following building error:

  CC    crypto/pbkdf.o
  CC    crypto/pbkdf-nettle.o
  CC    crypto/ivgen.o
crypto/pbkdf-nettle.c:23:27: error: nettle/pbkdf2.h: No such file or directory
crypto/pbkdf-nettle.c: In function ‘qcrypto_pbkdf2’:
crypto/pbkdf-nettle.c:46: warning: implicit declaration of function ‘pbkdf2_hmac_sha1’
crypto/pbkdf-nettle.c:46: warning: nested extern declaration of ‘pbkdf2_hmac_sha1’
crypto/pbkdf-nettle.c:53: warning: implicit declaration of function ‘pbkdf2_hmac_sha256’
crypto/pbkdf-nettle.c:53: warning: nested extern declaration of ‘pbkdf2_hmac_sha256’
make: *** [crypto/pbkdf-nettle.o] Error 1
make: *** Waiting for unfinished jobs....

rpm -qf /usr/include/nettle/
libnettle-devel-2.4-8.1.2

The nettle version is very old......
The OS is SUSE 11 SP3.

Thanks
Wen Congyang