crypto/cipher-afalg.c

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