qemu/crypto/cipher-afalg.c
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   1/*
   2 * QEMU Crypto af_alg-backend cipher support
   3 *
   4 * Copyright (c) 2017 HUAWEI TECHNOLOGIES CO., LTD.
   5 *
   6 * Authors:
   7 *    Longpeng(Mike) <longpeng2@huawei.com>
   8 *
   9 * This work is licensed under the terms of the GNU GPL, version 2 or
  10 * (at your option) any later version.  See the COPYING file in the
  11 * top-level directory.
  12 */
  13#include "qemu/osdep.h"
  14#include "qemu/sockets.h"
  15#include "qapi/error.h"
  16#include "crypto/cipher.h"
  17#include "cipherpriv.h"
  18
  19
  20static char *
  21qcrypto_afalg_cipher_format_name(QCryptoCipherAlgorithm alg,
  22                                 QCryptoCipherMode mode,
  23                                 Error **errp)
  24{
  25    char *name;
  26    const char *alg_name;
  27    const char *mode_name;
  28
  29    switch (alg) {
  30    case QCRYPTO_CIPHER_ALG_AES_128:
  31    case QCRYPTO_CIPHER_ALG_AES_192:
  32    case QCRYPTO_CIPHER_ALG_AES_256:
  33        alg_name = "aes";
  34        break;
  35    case QCRYPTO_CIPHER_ALG_CAST5_128:
  36        alg_name = "cast5";
  37        break;
  38    case QCRYPTO_CIPHER_ALG_SERPENT_128:
  39    case QCRYPTO_CIPHER_ALG_SERPENT_192:
  40    case QCRYPTO_CIPHER_ALG_SERPENT_256:
  41        alg_name = "serpent";
  42        break;
  43    case QCRYPTO_CIPHER_ALG_TWOFISH_128:
  44    case QCRYPTO_CIPHER_ALG_TWOFISH_192:
  45    case QCRYPTO_CIPHER_ALG_TWOFISH_256:
  46        alg_name = "twofish";
  47        break;
  48
  49    default:
  50        error_setg(errp, "Unsupported cipher algorithm %d", alg);
  51        return NULL;
  52    }
  53
  54    mode_name = QCryptoCipherMode_str(mode);
  55    name = g_strdup_printf("%s(%s)", mode_name, alg_name);
  56
  57    return name;
  58}
  59
  60static const struct QCryptoCipherDriver qcrypto_cipher_afalg_driver;
  61
  62QCryptoCipher *
  63qcrypto_afalg_cipher_ctx_new(QCryptoCipherAlgorithm alg,
  64                             QCryptoCipherMode mode,
  65                             const uint8_t *key,
  66                             size_t nkey, Error **errp)
  67{
  68    QCryptoAFAlg *afalg;
  69    size_t expect_niv;
  70    char *name;
  71
  72    name = qcrypto_afalg_cipher_format_name(alg, mode, errp);
  73    if (!name) {
  74        return NULL;
  75    }
  76
  77    afalg = qcrypto_afalg_comm_alloc(AFALG_TYPE_CIPHER, name, errp);
  78    if (!afalg) {
  79        g_free(name);
  80        return NULL;
  81    }
  82
  83    g_free(name);
  84
  85    /* setkey */
  86    if (setsockopt(afalg->tfmfd, SOL_ALG, ALG_SET_KEY, key,
  87                   nkey) != 0) {
  88        error_setg_errno(errp, errno, "Set key failed");
  89        qcrypto_afalg_comm_free(afalg);
  90        return NULL;
  91    }
  92
  93    /* prepare msg header */
  94    afalg->msg = g_new0(struct msghdr, 1);
  95    afalg->msg->msg_controllen += CMSG_SPACE(ALG_OPTYPE_LEN);
  96    expect_niv = qcrypto_cipher_get_iv_len(alg, mode);
  97    if (expect_niv) {
  98        afalg->msg->msg_controllen += CMSG_SPACE(ALG_MSGIV_LEN(expect_niv));
  99    }
 100    afalg->msg->msg_control = g_new0(uint8_t, afalg->msg->msg_controllen);
 101
 102    /* We use 1st msghdr for crypto-info and 2nd msghdr for IV-info */
 103    afalg->cmsg = CMSG_FIRSTHDR(afalg->msg);
 104    afalg->cmsg->cmsg_type = ALG_SET_OP;
 105    afalg->cmsg->cmsg_len = CMSG_SPACE(ALG_OPTYPE_LEN);
 106    if (expect_niv) {
 107        afalg->cmsg = CMSG_NXTHDR(afalg->msg, afalg->cmsg);
 108        afalg->cmsg->cmsg_type = ALG_SET_IV;
 109        afalg->cmsg->cmsg_len = CMSG_SPACE(ALG_MSGIV_LEN(expect_niv));
 110    }
 111    afalg->cmsg = CMSG_FIRSTHDR(afalg->msg);
 112
 113    afalg->base.driver = &qcrypto_cipher_afalg_driver;
 114    return &afalg->base;
 115}
 116
 117static int
 118qcrypto_afalg_cipher_setiv(QCryptoCipher *cipher,
 119                           const uint8_t *iv,
 120                           size_t niv, Error **errp)
 121{
 122    QCryptoAFAlg *afalg = container_of(cipher, QCryptoAFAlg, base);
 123    struct af_alg_iv *alg_iv;
 124    size_t expect_niv;
 125
 126    expect_niv = qcrypto_cipher_get_iv_len(cipher->alg, cipher->mode);
 127    if (niv != expect_niv) {
 128        error_setg(errp, "Set IV len(%zu) not match expected(%zu)",
 129                   niv, expect_niv);
 130        return -1;
 131    }
 132
 133    /* move ->cmsg to next msghdr, for IV-info */
 134    afalg->cmsg = CMSG_NXTHDR(afalg->msg, afalg->cmsg);
 135
 136    /* build setiv msg */
 137    afalg->cmsg->cmsg_level = SOL_ALG;
 138    alg_iv = (struct af_alg_iv *)CMSG_DATA(afalg->cmsg);
 139    alg_iv->ivlen = niv;
 140    memcpy(alg_iv->iv, iv, niv);
 141
 142    return 0;
 143}
 144
 145static int
 146qcrypto_afalg_cipher_op(QCryptoAFAlg *afalg,
 147                        const void *in, void *out,
 148                        size_t len, bool do_encrypt,
 149                        Error **errp)
 150{
 151    uint32_t *type = NULL;
 152    struct iovec iov;
 153    size_t ret, rlen, done = 0;
 154    uint32_t origin_controllen;
 155
 156    origin_controllen = afalg->msg->msg_controllen;
 157    /* movev ->cmsg to first header, for crypto-info */
 158    afalg->cmsg = CMSG_FIRSTHDR(afalg->msg);
 159
 160    /* build encrypt msg */
 161    afalg->cmsg->cmsg_level = SOL_ALG;
 162    afalg->msg->msg_iov = &iov;
 163    afalg->msg->msg_iovlen = 1;
 164    type = (uint32_t *)CMSG_DATA(afalg->cmsg);
 165    if (do_encrypt) {
 166        *type = ALG_OP_ENCRYPT;
 167    } else {
 168        *type = ALG_OP_DECRYPT;
 169    }
 170
 171    do {
 172        iov.iov_base = (void *)in + done;
 173        iov.iov_len = len - done;
 174
 175        /* send info to AF_ALG core */
 176        ret = sendmsg(afalg->opfd, afalg->msg, 0);
 177        if (ret == -1) {
 178            error_setg_errno(errp, errno, "Send data to AF_ALG core failed");
 179            return -1;
 180        }
 181
 182        /* encrypto && get result */
 183        rlen = read(afalg->opfd, out, ret);
 184        if (rlen == -1) {
 185            error_setg_errno(errp, errno, "Get result from AF_ALG core failed");
 186            return -1;
 187        }
 188        assert(rlen == ret);
 189
 190        /* do not update IV for following chunks */
 191        afalg->msg->msg_controllen = 0;
 192        done += ret;
 193    } while (done < len);
 194
 195    afalg->msg->msg_controllen = origin_controllen;
 196
 197    return 0;
 198}
 199
 200static int
 201qcrypto_afalg_cipher_encrypt(QCryptoCipher *cipher,
 202                             const void *in, void *out,
 203                             size_t len, Error **errp)
 204{
 205    QCryptoAFAlg *afalg = container_of(cipher, QCryptoAFAlg, base);
 206
 207    return qcrypto_afalg_cipher_op(afalg, in, out, len, true, errp);
 208}
 209
 210static int
 211qcrypto_afalg_cipher_decrypt(QCryptoCipher *cipher,
 212                             const void *in, void *out,
 213                             size_t len, Error **errp)
 214{
 215    QCryptoAFAlg *afalg = container_of(cipher, QCryptoAFAlg, base);
 216
 217    return qcrypto_afalg_cipher_op(afalg, in, out, len, false, errp);
 218}
 219
 220static void qcrypto_afalg_comm_ctx_free(QCryptoCipher *cipher)
 221{
 222    QCryptoAFAlg *afalg = container_of(cipher, QCryptoAFAlg, base);
 223
 224    qcrypto_afalg_comm_free(afalg);
 225}
 226
 227static const struct QCryptoCipherDriver qcrypto_cipher_afalg_driver = {
 228    .cipher_encrypt = qcrypto_afalg_cipher_encrypt,
 229    .cipher_decrypt = qcrypto_afalg_cipher_decrypt,
 230    .cipher_setiv = qcrypto_afalg_cipher_setiv,
 231    .cipher_free = qcrypto_afalg_comm_ctx_free,
 232};
 233