/*

 * Copyright 2016-2021 The OpenSSL Project Authors. All Rights Reserved.

 *

 * Licensed under the OpenSSL license (the "License").  You may not use

 * this file except in compliance with the License.  You can obtain a copy

 * in the file LICENSE in the source distribution or at

 * https://www.openssl.org/source/license.html

 */

/* Required for vmsplice */

#ifndef _GNU_SOURCE

# define _GNU_SOURCE

#endif

#include <stdio.h>

#include <string.h>

#include <unistd.h>

#include <openssl/engine.h>

#include <openssl/async.h>

#include <openssl/err.h>

#include "internal/nelem.h"

#include <sys/socket.h>

#include <linux/version.h>

#define K_MAJ   4

#define K_MIN1  1

#define K_MIN2  0

#if LINUX_VERSION_CODE < KERNEL_VERSION(K_MAJ, K_MIN1, K_MIN2) || \

    !defined(AF_ALG)

# ifndef PEDANTIC

#  warning "AFALG ENGINE requires Kernel Headers >= 4.1.0"

#  warning "Skipping Compilation of AFALG engine"

# endif

void engine_load_afalg_int(void);

void engine_load_afalg_int(void)

{

}

#else

# include <linux/if_alg.h>

# include <fcntl.h>

# include <sys/utsname.h>

# include <linux/aio_abi.h>

# include <sys/syscall.h>

# include <errno.h>

# include "e_afalg.h"

# include "e_afalg_err.c"

# ifndef SOL_ALG

#  define SOL_ALG 279

# endif

# ifdef ALG_ZERO_COPY

#  ifndef SPLICE_F_GIFT

#   define SPLICE_F_GIFT    (0x08)

#  endif

# endif

# define ALG_AES_IV_LEN 16

# define ALG_IV_LEN(len) (sizeof(struct af_alg_iv) + (len))

# define ALG_OP_TYPE     unsigned int

# define ALG_OP_LEN      (sizeof(ALG_OP_TYPE))

# ifdef OPENSSL_NO_DYNAMIC_ENGINE

void engine_load_afalg_int(void);

# endif

/* Local Linkage Functions */

static int afalg_init_aio(afalg_aio *aio);

static int afalg_fin_cipher_aio(afalg_aio *ptr, int sfd,

                                unsigned char *buf, size_t len);

static int afalg_create_sk(afalg_ctx *actx, const char *ciphertype,

                                const char *ciphername);

static int afalg_destroy(ENGINE *e);

static int afalg_init(ENGINE *e);

static int afalg_finish(ENGINE *e);

static const EVP_CIPHER *afalg_aes_cbc(int nid);

static cbc_handles *get_cipher_handle(int nid);

static int afalg_ciphers(ENGINE *e, const EVP_CIPHER **cipher,

                         const int **nids, int nid);

static int afalg_cipher_init(EVP_CIPHER_CTX *ctx, const unsigned char *key,

                             const unsigned char *iv, int enc);

static int afalg_do_cipher(EVP_CIPHER_CTX *ctx, unsigned char *out,

                           const unsigned char *in, size_t inl);

static int afalg_cipher_cleanup(EVP_CIPHER_CTX *ctx);

static int afalg_chk_platform(void);

/* Engine Id and Name */

static const char *engine_afalg_id = "afalg";

static const char *engine_afalg_name = "AFALG engine support";

static int afalg_cipher_nids[] = {

    NID_aes_128_cbc,

    NID_aes_192_cbc,

    NID_aes_256_cbc,

};

static cbc_handles cbc_handle[] = {{AES_KEY_SIZE_128, NULL},

                                    {AES_KEY_SIZE_192, NULL},

                                    {AES_KEY_SIZE_256, NULL}};

static ossl_inline int io_setup(unsigned n, aio_context_t *ctx)

{

    return syscall(__NR_io_setup, n, ctx);

}

static ossl_inline int eventfd(int n)

{

    return syscall(__NR_eventfd2, n, 0);

}

static ossl_inline int io_destroy(aio_context_t ctx)

{

    return syscall(__NR_io_destroy, ctx);

}

static ossl_inline int io_read(aio_context_t ctx, long n, struct iocb **iocb)

{

    return syscall(__NR_io_submit, ctx, n, iocb);

}

static ossl_inline int io_getevents(aio_context_t ctx, long min, long max,

                               struct io_event *events,

                               struct timespec *timeout)

{

    return syscall(__NR_io_getevents, ctx, min, max, events, timeout);

}

static void afalg_waitfd_cleanup(ASYNC_WAIT_CTX *ctx, const void *key,

                                 OSSL_ASYNC_FD waitfd, void *custom)

{

    close(waitfd);

}

static int afalg_setup_async_event_notification(afalg_aio *aio)

{

    ASYNC_JOB *job;

    ASYNC_WAIT_CTX *waitctx;

    void *custom = NULL;

    int ret;

    if ((job = ASYNC_get_current_job()) != NULL) {

        /* Async mode */

        waitctx = ASYNC_get_wait_ctx(job);

        if (waitctx == NULL) {

            ALG_WARN("%s(%d): ASYNC_get_wait_ctx error", __FILE__, __LINE__);

            return 0;

        }

        /* Get waitfd from ASYNC_WAIT_CTX if it is already set */

        ret = ASYNC_WAIT_CTX_get_fd(waitctx, engine_afalg_id,

                                    &aio->efd, &custom);

        if (ret == 0) {

            /*

             * waitfd is not set in ASYNC_WAIT_CTX, create a new one

             * and set it. efd will be signaled when AIO operation completes

             */

            aio->efd = eventfd(0);

            if (aio->efd == -1) {

                ALG_PERR("%s(%d): Failed to get eventfd : ", __FILE__,

                         __LINE__);

                AFALGerr(AFALG_F_AFALG_SETUP_ASYNC_EVENT_NOTIFICATION,

                         AFALG_R_EVENTFD_FAILED);

                return 0;

            }

            ret = ASYNC_WAIT_CTX_set_wait_fd(waitctx, engine_afalg_id,

                                             aio->efd, custom,

                                             afalg_waitfd_cleanup);

            if (ret == 0) {

                ALG_WARN("%s(%d): Failed to set wait fd", __FILE__, __LINE__);

                close(aio->efd);

                return 0;

            }

            /* make fd non-blocking in async mode */

            if (fcntl(aio->efd, F_SETFL, O_NONBLOCK) != 0) {

                ALG_WARN("%s(%d): Failed to set event fd as NONBLOCKING",

                         __FILE__, __LINE__);

            }

        }

        aio->mode = MODE_ASYNC;

    } else {

        /* Sync mode */

        aio->efd = eventfd(0);

        if (aio->efd == -1) {

            ALG_PERR("%s(%d): Failed to get eventfd : ", __FILE__, __LINE__);

            AFALGerr(AFALG_F_AFALG_SETUP_ASYNC_EVENT_NOTIFICATION,

                     AFALG_R_EVENTFD_FAILED);

            return 0;

        }

        aio->mode = MODE_SYNC;

    }

    return 1;

}

static int afalg_init_aio(afalg_aio *aio)

{

    int r = -1;

    /* Initialise for AIO */

    aio->aio_ctx = 0;

    r = io_setup(MAX_INFLIGHTS, &aio->aio_ctx);

    if (r < 0) {

        ALG_PERR("%s(%d): io_setup error : ", __FILE__, __LINE__);

        AFALGerr(AFALG_F_AFALG_INIT_AIO, AFALG_R_IO_SETUP_FAILED);

        return 0;

    }

    memset(aio->cbt, 0, sizeof(aio->cbt));

    aio->efd = -1;

    aio->mode = MODE_UNINIT;

    return 1;

}

static int afalg_fin_cipher_aio(afalg_aio *aio, int sfd, unsigned char *buf,

                                size_t len)

{

    int r;

    int retry = 0;

    unsigned int done = 0;

    struct iocb *cb;

    struct timespec timeout;

    struct io_event events[MAX_INFLIGHTS];

    u_int64_t eval = 0;

    timeout.tv_sec = 0;

    timeout.tv_nsec = 0;

    /* if efd has not been initialised yet do it here */

    if (aio->mode == MODE_UNINIT) {

        r = afalg_setup_async_event_notification(aio);

        if (r == 0)

            return 0;

    }

    cb = &(aio->cbt[0 % MAX_INFLIGHTS]);

    memset(cb, '\0', sizeof(*cb));

    cb->aio_fildes = sfd;

    cb->aio_lio_opcode = IOCB_CMD_PREAD;

    /*

     * The pointer has to be converted to unsigned value first to avoid

     * sign extension on cast to 64 bit value in 32-bit builds

     */

    cb->aio_buf = (size_t)buf;

    cb->aio_offset = 0;

    cb->aio_data = 0;

    cb->aio_nbytes = len;

    cb->aio_flags = IOCB_FLAG_RESFD;

    cb->aio_resfd = aio->efd;

    /*

     * Perform AIO read on AFALG socket, this in turn performs an async

     * crypto operation in kernel space

     */

    r = io_read(aio->aio_ctx, 1, &cb);

    if (r < 0) {

        ALG_PWARN("%s(%d): io_read failed : ", __FILE__, __LINE__);

        return 0;

    }

    do {

        /* While AIO read is being performed pause job */

        ASYNC_pause_job();

        /* Check for completion of AIO read */

        r = read(aio->efd, &eval, sizeof(eval));

        if (r < 0) {

            if (errno == EAGAIN || errno == EWOULDBLOCK)

                continue;

            ALG_PERR("%s(%d): read failed for event fd : ", __FILE__, __LINE__);

            return 0;

        } else if (r == 0 || eval <= 0) {

            ALG_WARN("%s(%d): eventfd read %d bytes, eval = %lu\n", __FILE__,

                     __LINE__, r, eval);

        }

        if (eval > 0) {

            /* Get results of AIO read */

            r = io_getevents(aio->aio_ctx, 1, MAX_INFLIGHTS,

                             events, &timeout);

            if (r > 0) {

                /*

                 * events.res indicates the actual status of the operation.

                 * Handle the error condition first.

                 */

                if (events[0].res < 0) {

                    /*

                     * Underlying operation cannot be completed at the time

                     * of previous submission. Resubmit for the operation.

                     */

                    if (events[0].res == -EBUSY && retry++ < 3) {

                        r = io_read(aio->aio_ctx, 1, &cb);

                        if (r < 0) {

                            ALG_PERR("%s(%d): retry %d for io_read failed : ",

                                     __FILE__, __LINE__, retry);

                            return 0;

                        }

                        continue;

                    } else {

                        /*

                         * Retries exceed for -EBUSY or unrecoverable error

                         * condition for this instance of operation.

                         */

                        ALG_WARN

                            ("%s(%d): Crypto Operation failed with code %lld\n",

                             __FILE__, __LINE__, events[0].res);

                        return 0;

                    }

                }

                /* Operation successful. */

                done = 1;

            } else if (r < 0) {

                ALG_PERR("%s(%d): io_getevents failed : ", __FILE__, __LINE__);

                return 0;

            } else {

                ALG_WARN("%s(%d): io_geteventd read 0 bytes\n", __FILE__,

                         __LINE__);

            }

        }

    } while (!done);

    return 1;

}

static ossl_inline void afalg_set_op_sk(struct cmsghdr *cmsg,

                                   const ALG_OP_TYPE op)

{

    cmsg->cmsg_level = SOL_ALG;

    cmsg->cmsg_type = ALG_SET_OP;

    cmsg->cmsg_len = CMSG_LEN(ALG_OP_LEN);

    memcpy(CMSG_DATA(cmsg), &op, ALG_OP_LEN);

}

static void afalg_set_iv_sk(struct cmsghdr *cmsg, const unsigned char *iv,

                            const unsigned int len)

{

    struct af_alg_iv *aiv;

    cmsg->cmsg_level = SOL_ALG;

    cmsg->cmsg_type = ALG_SET_IV;

    cmsg->cmsg_len = CMSG_LEN(ALG_IV_LEN(len));

    aiv = (struct af_alg_iv *)CMSG_DATA(cmsg);

    aiv->ivlen = len;

    memcpy(aiv->iv, iv, len);

}

static ossl_inline int afalg_set_key(afalg_ctx *actx, const unsigned char *key,

                                const int klen)

{

    int ret;

    ret = setsockopt(actx->bfd, SOL_ALG, ALG_SET_KEY, key, klen);

    if (ret < 0) {

        ALG_PERR("%s(%d): Failed to set socket option : ", __FILE__, __LINE__);

        AFALGerr(AFALG_F_AFALG_SET_KEY, AFALG_R_SOCKET_SET_KEY_FAILED);

        return 0;

    }

    return 1;

}

static int afalg_create_sk(afalg_ctx *actx, const char *ciphertype,

                                const char *ciphername)

{

    struct sockaddr_alg sa;

    int r = -1;

    actx->bfd = actx->sfd = -1;

    memset(&sa, 0, sizeof(sa));

    sa.salg_family = AF_ALG;

    OPENSSL_strlcpy((char *) sa.salg_type, ciphertype, sizeof(sa.salg_type));

    OPENSSL_strlcpy((char *) sa.salg_name, ciphername, sizeof(sa.salg_name));

    actx->bfd = socket(AF_ALG, SOCK_SEQPACKET, 0);

    if (actx->bfd == -1) {

        ALG_PERR("%s(%d): Failed to open socket : ", __FILE__, __LINE__);

        AFALGerr(AFALG_F_AFALG_CREATE_SK, AFALG_R_SOCKET_CREATE_FAILED);

        goto err;

    }

    r = bind(actx->bfd, (struct sockaddr *)&sa, sizeof(sa));

    if (r < 0) {

        ALG_PERR("%s(%d): Failed to bind socket : ", __FILE__, __LINE__);

        AFALGerr(AFALG_F_AFALG_CREATE_SK, AFALG_R_SOCKET_BIND_FAILED);

        goto err;

    }

    actx->sfd = accept(actx->bfd, NULL, 0);

    if (actx->sfd < 0) {

        ALG_PERR("%s(%d): Socket Accept Failed : ", __FILE__, __LINE__);

        AFALGerr(AFALG_F_AFALG_CREATE_SK, AFALG_R_SOCKET_ACCEPT_FAILED);

        goto err;

    }

    return 1;

 err:

    if (actx->bfd >= 0)

        close(actx->bfd);

    if (actx->sfd >= 0)

        close(actx->sfd);

    actx->bfd = actx->sfd = -1;

    return 0;

}

static int afalg_start_cipher_sk(afalg_ctx *actx, const unsigned char *in,

                                 size_t inl, const unsigned char *iv,

                                 unsigned int enc)

{

    struct msghdr msg = { 0 };

    struct cmsghdr *cmsg;

    struct iovec iov;

    ssize_t sbytes;

# ifdef ALG_ZERO_COPY

    int ret;

# endif

    char cbuf[CMSG_SPACE(ALG_IV_LEN(ALG_AES_IV_LEN)) + CMSG_SPACE(ALG_OP_LEN)];

    memset(cbuf, 0, sizeof(cbuf));

    msg.msg_control = cbuf;

    msg.msg_controllen = sizeof(cbuf);

    /*

     * cipher direction (i.e. encrypt or decrypt) and iv are sent to the

     * kernel as part of sendmsg()'s ancillary data

     */

    cmsg = CMSG_FIRSTHDR(&msg);

    afalg_set_op_sk(cmsg, enc);

    cmsg = CMSG_NXTHDR(&msg, cmsg);

    afalg_set_iv_sk(cmsg, iv, ALG_AES_IV_LEN);

    /* iov that describes input data */

    iov.iov_base = (unsigned char *)in;

    iov.iov_len = inl;

    msg.msg_flags = MSG_MORE;

# ifdef ALG_ZERO_COPY

    /*

     * ZERO_COPY mode

     * Works best when buffer is 4k aligned

     * OPENS: out of place processing (i.e. out != in)

     */

    /* Input data is not sent as part of call to sendmsg() */

    msg.msg_iovlen = 0;

    msg.msg_iov = NULL;

    /* Sendmsg() sends iv and cipher direction to the kernel */

    sbytes = sendmsg(actx->sfd, &msg, 0);

    if (sbytes < 0) {

        ALG_PERR("%s(%d): sendmsg failed for zero copy cipher operation : ",

                 __FILE__, __LINE__);

        return 0;

    }

    /*

     * vmsplice and splice are used to pin the user space input buffer for

     * kernel space processing avoiding copies from user to kernel space

     */

    ret = vmsplice(actx->zc_pipe[1], &iov, 1, SPLICE_F_GIFT);

    if (ret < 0) {

        ALG_PERR("%s(%d): vmsplice failed : ", __FILE__, __LINE__);

        return 0;

    }

    ret = splice(actx->zc_pipe[0], NULL, actx->sfd, NULL, inl, 0);

    if (ret < 0) {

        ALG_PERR("%s(%d): splice failed : ", __FILE__, __LINE__);

        return 0;

    }

# else

    msg.msg_iovlen = 1;

    msg.msg_iov = &iov;

    /* Sendmsg() sends iv, cipher direction and input data to the kernel */

    sbytes = sendmsg(actx->sfd, &msg, 0);

    if (sbytes < 0) {

        ALG_PERR("%s(%d): sendmsg failed for cipher operation : ", __FILE__,

                 __LINE__);

        return 0;

    }

    if (sbytes != (ssize_t) inl) {

        ALG_WARN("Cipher operation send bytes %zd != inlen %zd\n", sbytes,

                inl);

        return 0;

    }

# endif

    return 1;

}

static int afalg_cipher_init(EVP_CIPHER_CTX *ctx, const unsigned char *key,

                             const unsigned char *iv, int enc)

{

    int ciphertype;

    int ret;

    afalg_ctx *actx;

    const char *ciphername;

    if (ctx == NULL || key == NULL) {

        ALG_WARN("%s(%d): Null Parameter\n", __FILE__, __LINE__);

        return 0;

    }

    if (EVP_CIPHER_CTX_cipher(ctx) == NULL) {

        ALG_WARN("%s(%d): Cipher object NULL\n", __FILE__, __LINE__);

        return 0;

    }

    actx = EVP_CIPHER_CTX_get_cipher_data(ctx);

    if (actx == NULL) {

        ALG_WARN("%s(%d): Cipher data NULL\n", __FILE__, __LINE__);

        return 0;

    }

    ciphertype = EVP_CIPHER_CTX_nid(ctx);

    switch (ciphertype) {

    case NID_aes_128_cbc:

    case NID_aes_192_cbc:

    case NID_aes_256_cbc:

        ciphername = "cbc(aes)";

        break;

    default:

        ALG_WARN("%s(%d): Unsupported Cipher type %d\n", __FILE__, __LINE__,

                 ciphertype);

        return 0;

    }

    if (ALG_AES_IV_LEN != EVP_CIPHER_CTX_iv_length(ctx)) {

        ALG_WARN("%s(%d): Unsupported IV length :%d\n", __FILE__, __LINE__,

                 EVP_CIPHER_CTX_iv_length(ctx));

        return 0;

    }

    /* Setup AFALG socket for crypto processing */

    ret = afalg_create_sk(actx, "skcipher", ciphername);

    if (ret < 1)

        return 0;

    ret = afalg_set_key(actx, key, EVP_CIPHER_CTX_key_length(ctx));

    if (ret < 1)

        goto err;

    /* Setup AIO ctx to allow async AFALG crypto processing */

    if (afalg_init_aio(&actx->aio) == 0)

        goto err;

# ifdef ALG_ZERO_COPY

    pipe(actx->zc_pipe);

# endif

    actx->init_done = MAGIC_INIT_NUM;

    return 1;

err:

    close(actx->sfd);

    close(actx->bfd);

    return 0;

}

static int afalg_do_cipher(EVP_CIPHER_CTX *ctx, unsigned char *out,

                           const unsigned char *in, size_t inl)

{

    afalg_ctx *actx;

    int ret;

    char nxtiv[ALG_AES_IV_LEN] = { 0 };

    if (ctx == NULL || out == NULL || in == NULL) {

        ALG_WARN("NULL parameter passed to function %s(%d)\n", __FILE__,

                 __LINE__);

        return 0;

    }

    actx = (afalg_ctx *) EVP_CIPHER_CTX_get_cipher_data(ctx);

    if (actx == NULL || actx->init_done != MAGIC_INIT_NUM) {

        ALG_WARN("%s afalg ctx passed\n",

                 ctx == NULL ? "NULL" : "Uninitialised");

        return 0;

    }

    /*

     * set iv now for decrypt operation as the input buffer can be

     * overwritten for inplace operation where in = out.

     */

    if (EVP_CIPHER_CTX_encrypting(ctx) == 0) {

        memcpy(nxtiv, in + (inl - ALG_AES_IV_LEN), ALG_AES_IV_LEN);

    }

    /* Send input data to kernel space */

    ret = afalg_start_cipher_sk(actx, (unsigned char *)in, inl,

                                EVP_CIPHER_CTX_iv(ctx),

                                EVP_CIPHER_CTX_encrypting(ctx));

    if (ret < 1) {

        return 0;

    }

    /* Perform async crypto operation in kernel space */

    ret = afalg_fin_cipher_aio(&actx->aio, actx->sfd, out, inl);

    if (ret < 1)

        return 0;

    if (EVP_CIPHER_CTX_encrypting(ctx)) {

        memcpy(EVP_CIPHER_CTX_iv_noconst(ctx), out + (inl - ALG_AES_IV_LEN),

               ALG_AES_IV_LEN);

    } else {

        memcpy(EVP_CIPHER_CTX_iv_noconst(ctx), nxtiv, ALG_AES_IV_LEN);

    }

    return 1;

}

static int afalg_cipher_cleanup(EVP_CIPHER_CTX *ctx)

{

    afalg_ctx *actx;

    if (ctx == NULL) {

        ALG_WARN("NULL parameter passed to function %s(%d)\n", __FILE__,

                 __LINE__);

        return 0;

    }

    actx = (afalg_ctx *) EVP_CIPHER_CTX_get_cipher_data(ctx);

    if (actx == NULL || actx->init_done != MAGIC_INIT_NUM)

        return 1;

    close(actx->sfd);

    close(actx->bfd);

# ifdef ALG_ZERO_COPY

    close(actx->zc_pipe[0]);

    close(actx->zc_pipe[1]);

# endif

    /* close efd in sync mode, async mode is closed in afalg_waitfd_cleanup() */

    if (actx->aio.mode == MODE_SYNC)

        close(actx->aio.efd);

    io_destroy(actx->aio.aio_ctx);

    return 1;

}

static cbc_handles *get_cipher_handle(int nid)

{

    switch (nid) {

    case NID_aes_128_cbc:

        return &cbc_handle[AES_CBC_128];

    case NID_aes_192_cbc:

        return &cbc_handle[AES_CBC_192];

    case NID_aes_256_cbc:

        return &cbc_handle[AES_CBC_256];

    default:

        return NULL;

    }

}

static const EVP_CIPHER *afalg_aes_cbc(int nid)

{

    cbc_handles *cipher_handle = get_cipher_handle(nid);

    if (cipher_handle->_hidden == NULL

        && ((cipher_handle->_hidden =

         EVP_CIPHER_meth_new(nid,

                             AES_BLOCK_SIZE,

                             cipher_handle->key_size)) == NULL

        || !EVP_CIPHER_meth_set_iv_length(cipher_handle->_hidden,

                                          AES_IV_LEN)

        || !EVP_CIPHER_meth_set_flags(cipher_handle->_hidden,

                                      EVP_CIPH_CBC_MODE |

                                      EVP_CIPH_FLAG_DEFAULT_ASN1)

        || !EVP_CIPHER_meth_set_init(cipher_handle->_hidden,

                                     afalg_cipher_init)

        || !EVP_CIPHER_meth_set_do_cipher(cipher_handle->_hidden,

                                          afalg_do_cipher)

        || !EVP_CIPHER_meth_set_cleanup(cipher_handle->_hidden,

                                        afalg_cipher_cleanup)

        || !EVP_CIPHER_meth_set_impl_ctx_size(cipher_handle->_hidden,

                                              sizeof(afalg_ctx)))) {

        EVP_CIPHER_meth_free(cipher_handle->_hidden);

        cipher_handle->_hidden= NULL;

    }

    return cipher_handle->_hidden;

}

static int afalg_ciphers(ENGINE *e, const EVP_CIPHER **cipher,

                         const int **nids, int nid)

{

    int r = 1;

    if (cipher == NULL) {

        *nids = afalg_cipher_nids;

        return (sizeof(afalg_cipher_nids) / sizeof(afalg_cipher_nids[0]));

    }

    switch (nid) {

    case NID_aes_128_cbc:

    case NID_aes_192_cbc:

    case NID_aes_256_cbc:

        *cipher = afalg_aes_cbc(nid);

        break;

    default:

        *cipher = NULL;

        r = 0;

    }

    return r;

}

static int bind_afalg(ENGINE *e)

{

    /* Ensure the afalg error handling is set up */

    unsigned short i;

    ERR_load_AFALG_strings();

    if (!ENGINE_set_id(e, engine_afalg_id)

        || !ENGINE_set_name(e, engine_afalg_name)

        || !ENGINE_set_destroy_function(e, afalg_destroy)

        || !ENGINE_set_init_function(e, afalg_init)

        || !ENGINE_set_finish_function(e, afalg_finish)) {

        AFALGerr(AFALG_F_BIND_AFALG, AFALG_R_INIT_FAILED);

        return 0;

    }

    /*

     * Create _hidden_aes_xxx_cbc by calling afalg_aes_xxx_cbc

     * now, as bind_aflag can only be called by one thread at a

     * time.

     */

    for(i = 0; i < OSSL_NELEM(afalg_cipher_nids); i++) {

        if (afalg_aes_cbc(afalg_cipher_nids[i]) == NULL) {

            AFALGerr(AFALG_F_BIND_AFALG, AFALG_R_INIT_FAILED);

            return 0;

        }

    }

    if (!ENGINE_set_ciphers(e, afalg_ciphers)) {

        AFALGerr(AFALG_F_BIND_AFALG, AFALG_R_INIT_FAILED);

        return 0;

    }

    return 1;

}

# ifndef OPENSSL_NO_DYNAMIC_ENGINE

static int bind_helper(ENGINE *e, const char *id)

{

    if (id && (strcmp(id, engine_afalg_id) != 0))

        return 0;

    if (!afalg_chk_platform())

        return 0;

    if (!bind_afalg(e))

        return 0;

    return 1;

}

IMPLEMENT_DYNAMIC_CHECK_FN()

    IMPLEMENT_DYNAMIC_BIND_FN(bind_helper)

# endif

static int afalg_chk_platform(void)

{

    int ret;

    int i;

    int kver[3] = { -1, -1, -1 };

    int sock;

    char *str;

    struct utsname ut;

    ret = uname(&ut);

    if (ret != 0) {

        AFALGerr(AFALG_F_AFALG_CHK_PLATFORM,

                 AFALG_R_FAILED_TO_GET_PLATFORM_INFO);

        return 0;

    }

    str = strtok(ut.release, ".");

    for (i = 0; i < 3 && str != NULL; i++) {

        kver[i] = atoi(str);

        str = strtok(NULL, ".");

    }

    if (KERNEL_VERSION(kver[0], kver[1], kver[2])

        < KERNEL_VERSION(K_MAJ, K_MIN1, K_MIN2)) {

        ALG_ERR("ASYNC AFALG not supported this kernel(%d.%d.%d)\n",

                 kver[0], kver[1], kver[2]);

        ALG_ERR("ASYNC AFALG requires kernel version %d.%d.%d or later\n",

                 K_MAJ, K_MIN1, K_MIN2);

        AFALGerr(AFALG_F_AFALG_CHK_PLATFORM,

                 AFALG_R_KERNEL_DOES_NOT_SUPPORT_ASYNC_AFALG);

        return 0;

    }

    /* Test if we can actually create an AF_ALG socket */

    sock = socket(AF_ALG, SOCK_SEQPACKET, 0);

    if (sock == -1) {

        AFALGerr(AFALG_F_AFALG_CHK_PLATFORM, AFALG_R_SOCKET_CREATE_FAILED);

        return 0;

    }

    close(sock);

    return 1;

}

# ifdef OPENSSL_NO_DYNAMIC_ENGINE

static ENGINE *engine_afalg(void)

{

    ENGINE *ret = ENGINE_new();

    if (ret == NULL)

        return NULL;

    if (!bind_afalg(ret)) {

        ENGINE_free(ret);

        return NULL;

    }

    return ret;

}

void engine_load_afalg_int(void)

{

    ENGINE *toadd;

    if (!afalg_chk_platform())

        return;

    toadd = engine_afalg();

    if (toadd == NULL)

        return;

    ENGINE_add(toadd);

    ENGINE_free(toadd);

    ERR_clear_error();

}

# endif

static int afalg_init(ENGINE *e)

{

    return 1;

}

static int afalg_finish(ENGINE *e)

{

    return 1;

}

static int free_cbc(void)

{

    short unsigned int i;

    for(i = 0; i < OSSL_NELEM(afalg_cipher_nids); i++) {

        EVP_CIPHER_meth_free(cbc_handle[i]._hidden);

        cbc_handle[i]._hidden = NULL;

    }

    return 1;

}

static int afalg_destroy(ENGINE *e)

{

    ERR_unload_AFALG_strings();

    free_cbc();

    return 1;

}

#endif                          /* KERNEL VERSION */