一文了解LinuxKernel中密码学算法的设计与应用

socket(AF_ALG,...)bind()setsockoptacceptsendmsgrecvmsg

static int linux_af_alg_socket(const char *type, const char *name){  struct sockaddr_alg sa;  int s;
  s = socket(AF_ALG, SOCK_SEQPACKET, 0);  if (s < 0) {    LogErr("%s: Failed to open AF_ALG socket: %s\n",         __func__, strerror(errno));    return -1;  }
  os_memset(&sa, 0, sizeof(sa));  sa.salg_family = AF_ALG;  os_strlcpy((char *) sa.salg_type, type, sizeof(sa.salg_type));  os_strlcpy((char *) sa.salg_name, name, sizeof(sa.salg_name));  if (bind(s, (struct sockaddr *) &sa, sizeof(sa)) < 0) {    LogErr("%s: Failed to bind AF_ALG socket(%s,%s): %s\n",__func__, (char *) sa.salg_type, (char *) sa.salg_name, strerror(errno));    close(s);    return -1;  }
  return s;}
static struct linux_af_alg_skcipher *linux_af_alg_skcipher(const char *alg, const u8 *key, size_t key_len){  struct linux_af_alg_skcipher *skcipher;
  skcipher = os_zalloc(sizeof(*skcipher));  if (!skcipher)    goto fail;  skcipher->t = -1;
  skcipher->s = linux_af_alg_socket(TYPE_NAME, alg);  if (skcipher->s < 0)    goto fail;
  if (setsockopt(skcipher->s, SOL_ALG, ALG_SET_KEY, key, key_len) < 0) {    LogErr("%s: setsockopt(ALG_SET_KEY) failed: %s\n",         __func__, strerror(errno));    goto fail;  }
  skcipher->t = accept(skcipher->s, NULL, NULL);  if (skcipher->t < 0) {    LogErr("%s: accept on AF_ALG socket failed: %s\n",         __func__, strerror(errno));    goto fail;  }
  return skcipher;fail:  linux_af_alg_skcipher_deinit(skcipher);  return NULL;}
static int aes_128_cbc_oper(char *alg_name, const u8 *key,size_t key_len, int enc, const u8 *iv, u8 *data, size_t data_len){  struct linux_af_alg_skcipher *skcipher;  char buf[100];  struct iovec io[1];  struct msghdr msg;  struct cmsghdr *hdr;  ssize_t ret;  u32 *op;  struct af_alg_iv *alg_iv;  size_t iv_len = AES_BLOCK_SIZE;
  skcipher = linux_af_alg_skcipher(alg_name, key, key_len);//alg_name = "__cbc-aes-asr-ce"  if (!skcipher)    return -1;
  io[0].iov_base = (void *) data;  io[0].iov_len = data_len;  os_memset(&msg, 0, sizeof(msg));  os_memset(buf, 0, sizeof(buf));  msg.msg_control = buf;  msg.msg_controllen = CMSG_SPACE(sizeof(u32)) +    CMSG_SPACE(sizeof(*alg_iv) + iv_len);  msg.msg_iov = io;  msg.msg_iovlen = 1;
  hdr = CMSG_FIRSTHDR(&msg);  hdr->cmsg_level = SOL_ALG;  hdr->cmsg_type = ALG_SET_OP;  hdr->cmsg_len = CMSG_LEN(sizeof(u32));  op = (u32 *) CMSG_DATA(hdr);  *op = enc ? ALG_OP_ENCRYPT : ALG_OP_DECRYPT;
  hdr = CMSG_NXTHDR(&msg, hdr);  hdr->cmsg_level = SOL_ALG;  hdr->cmsg_type = ALG_SET_IV;  hdr->cmsg_len = CMSG_SPACE(sizeof(*alg_iv) + iv_len);  alg_iv = (struct af_alg_iv *) CMSG_DATA(hdr);  if(NULL != iv){    alg_iv->ivlen = iv_len;    os_memcpy(alg_iv->iv, iv, iv_len);  }else  {    alg_iv->ivlen = 0;  }
  ret = sendmsg(skcipher->t, &msg, 0);  if (ret < 0) {    LogErr("%s: sendmsg failed: %s\n",         __func__, strerror(errno));    linux_af_alg_skcipher_deinit(skcipher);    return -1;  }
  ret = recvmsg(skcipher->t, &msg, 0);  if (ret < 0) {    LogErr("%s: recvmsg failed: %s\n",         __func__, strerror(errno));    linux_af_alg_skcipher_deinit(skcipher);    return -1;  }  if ((size_t) ret < data_len) {    LogErr(         "%s: recvmsg not return full data (%d/%d)\n",         __func__, (int) ret, (int) data_len);    linux_af_alg_skcipher_deinit(skcipher);    return -1;  }
  //s_to_binary(data,data_len);  linux_af_alg_skcipher_deinit(skcipher);  return 0;}

static int test_skcipher(void){        struct crypto_skcipher *tfm = NULL;        struct skcipher_request *req = NULL;        u8 *data = NULL;        const size_t datasize = 512; /* data size in bytes */        struct scatterlist sg;        DECLARE_CRYPTO_WAIT(wait);        u8 iv[16];  /* AES-256-XTS takes a 16-byte IV */        u8 key[64]; /* AES-256-XTS takes a 64-byte key */        int err;
        /*         * Allocate a tfm (a transformation object) and set the key.         *         * In real-world use, a tfm and key are typically used for many         * encryption/decryption operations.  But in this example, we'll just do a         * single encryption operation with it (which is not very efficient).         */
        tfm = crypto_alloc_skcipher("xts(aes)", 0, 0);        if (IS_ERR(tfm)) {                pr_err("Error allocating xts(aes) handle: %ld\n", PTR_ERR(tfm));                return PTR_ERR(tfm);        }
        get_random_bytes(key, sizeof(key));        err = crypto_skcipher_setkey(tfm, key, sizeof(key));        if (err) {                pr_err("Error setting key: %d\n", err);                goto out;        }
        /* Allocate a request object */        req = skcipher_request_alloc(tfm, GFP_KERNEL);        if (!req) {                err = -ENOMEM;                goto out;        }
        /* Prepare the input data */        data = kmalloc(datasize, GFP_KERNEL);        if (!data) {                err = -ENOMEM;                goto out;        }        get_random_bytes(data, datasize);
        /* Initialize the IV */        get_random_bytes(iv, sizeof(iv));
        /*         * Encrypt the data in-place.         *         * For simplicity, in this example we wait for the request to complete         * before proceeding, even if the underlying implementation is asynchronous.         *         * To decrypt instead of encrypt, just change crypto_skcipher_encrypt() to         * crypto_skcipher_decrypt().         */        sg_init_one(&sg, data, datasize);        skcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG |                                           CRYPTO_TFM_REQ_MAY_SLEEP,                                      crypto_req_done, &wait);        skcipher_request_set_crypt(req, &sg, &sg, datasize, iv);        err = crypto_wait_req(crypto_skcipher_encrypt(req), &wait);        if (err) {                pr_err("Error encrypting data: %d\n", err);                goto out;        }
        pr_debug("Encryption was successful\n");out:        crypto_free_skcipher(tfm);        skcipher_request_free(req);        kfree(data);        return err;}

static struct skcipher_alg aes_algs[] = {   {    .base.cra_name    = "__ecb(aes)",    .base.cra_driver_name  = "__ecb-aes-neonbs",    .base.cra_priority  = 250,    .base.cra_blocksize  = AES_BLOCK_SIZE,    .base.cra_ctxsize  = sizeof(struct aesbs_ctx),    .base.cra_module  = THIS_MODULE,    .base.cra_flags    = CRYPTO_ALG_INTERNAL,
    .min_keysize    = AES_MIN_KEY_SIZE,    .max_keysize    = AES_MAX_KEY_SIZE,    .walksize    = 8 * AES_BLOCK_SIZE,    .setkey      = aesbs_setkey,    .encrypt    = ecb_encrypt,    .decrypt    = ecb_decrypt,  }, 
  {    .base.cra_name    = "__cbc(aes)",    .base.cra_driver_name  = "__cbc-aes-neonbs",    .base.cra_priority  = 250,    .base.cra_blocksize  = AES_BLOCK_SIZE,    .base.cra_ctxsize  = sizeof(struct aesbs_cbc_ctx),    .base.cra_module  = THIS_MODULE,    .base.cra_flags    = CRYPTO_ALG_INTERNAL,
    .min_keysize    = AES_MIN_KEY_SIZE,    .max_keysize    = AES_MAX_KEY_SIZE,    .walksize    = 8 * AES_BLOCK_SIZE,    .ivsize      = AES_BLOCK_SIZE,    .setkey      = aesbs_cbc_setkey,    .encrypt    = cbc_encrypt,    .decrypt    = cbc_decrypt,  }};

static int ecb_encrypt(struct skcipher_request *req){  return __ecb_crypt(req, aesbs_ecb_encrypt);}

static int __init aes_init(void){...  err = crypto_register_skciphers(aes_algs, ARRAY_SIZE(aes_algs));...}module_init(aes_init);

{  .name = "cbc(aes)",  .driver_name = "cbc-aes-ccree",  .blocksize = AES_BLOCK_SIZE,  .template_skcipher = {    .setkey = cc_cipher_setkey,    .encrypt = cc_cipher_encrypt,    .decrypt = cc_cipher_decrypt,    .min_keysize = AES_MIN_KEY_SIZE,    .max_keysize = AES_MAX_KEY_SIZE,    .ivsize = AES_BLOCK_SIZE,  },  .cipher_mode = DRV_CIPHER_CBC,  .flow_mode = S_DIN_to_AES,  .min_hw_rev = CC_HW_REV_630,  .std_body = CC_STD_NIST,}