Use more consistent naming for some files in evp

EVP_Digest{Init,Update,Final}() move from digest.c to evp_digest.c which
will become the home of all things related to EVP_MD{,_CTX} handling.

EVP_Cipher{Init,Update,Final}() move from evp_enc.c to evp_cipher.c which
will become the home of all things related to EVP_CIPHER{,_CTX} handling.

EVP_Encode{Init,Update,Final}() move from encode.c to evp_encode.c which
already is the home of EVP_ENCODE_CTX_{new,free}().

discussed with jsing

1 files changed, 687 insertions, 0 deletions

diff --git a/src/lib/libcrypto/evp/evp_cipher.c b/src/lib/libcrypto/evp/evp_cipher.c
new file mode 100644
index 0000000000..3b38e18bf3
--- /dev/null
+++ b/src/lib/libcrypto/evp/evp_cipher.c
@@ -0,0 +1,687 @@
+/* $OpenBSD: evp_cipher.c,v 1.1 2023/12/29 05:57:24 tb Exp $ */
+/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
+ * All rights reserved.
+ *
+ * This package is an SSL implementation written
+ * by Eric Young (eay@cryptsoft.com).
+ * The implementation was written so as to conform with Netscapes SSL.
+ *
+ * This library is free for commercial and non-commercial use as long as
+ * the following conditions are aheared to.  The following conditions
+ * apply to all code found in this distribution, be it the RC4, RSA,
+ * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
+ * included with this distribution is covered by the same copyright terms
+ * except that the holder is Tim Hudson (tjh@cryptsoft.com).
+ *
+ * Copyright remains Eric Young's, and as such any Copyright notices in
+ * the code are not to be removed.
+ * If this package is used in a product, Eric Young should be given attribution
+ * as the author of the parts of the library used.
+ * This can be in the form of a textual message at program startup or
+ * in documentation (online or textual) provided with the package.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *    "This product includes cryptographic software written by
+ *     Eric Young (eay@cryptsoft.com)"
+ *    The word 'cryptographic' can be left out if the rouines from the library
+ *    being used are not cryptographic related :-).
+ * 4. If you include any Windows specific code (or a derivative thereof) from
+ *    the apps directory (application code) you must include an acknowledgement:
+ *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
+ *
+ * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * The licence and distribution terms for any publically available version or
+ * derivative of this code cannot be changed.  i.e. this code cannot simply be
+ * copied and put under another distribution licence
+ * [including the GNU Public Licence.]
+ */
+
+#include <limits.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <openssl/opensslconf.h>
+
+#include <openssl/err.h>
+#include <openssl/evp.h>
+
+#include "evp_local.h"
+
+int
+EVP_CipherInit(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *cipher,
+    const unsigned char *key, const unsigned char *iv, int enc)
+{
+        return EVP_CipherInit_ex(ctx, cipher, NULL, key, iv, enc);
+}
+
+int
+EVP_CipherInit_ex(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *cipher, ENGINE *engine,
+    const unsigned char *key, const unsigned char *iv, int enc)
+{
+        if (enc == -1)
+                enc = ctx->encrypt;
+        if (enc != 0)
+                enc = 1;
+        ctx->encrypt = enc;
+
+        if (cipher == NULL && ctx->cipher == NULL) {
+                EVPerror(EVP_R_NO_CIPHER_SET);
+                return 0;
+        }
+
+        /*
+         * Set up cipher and context. Allocate cipher data and initialize ctx.
+         * On ctx reuse only retain encryption direction and key wrap flag.
+         */
+        if (cipher != NULL) {
+                unsigned long flags = ctx->flags;
+
+                EVP_CIPHER_CTX_cleanup(ctx);
+                ctx->encrypt = enc;
+                ctx->flags = flags & EVP_CIPHER_CTX_FLAG_WRAP_ALLOW;
+
+                ctx->cipher = cipher;
+                ctx->key_len = cipher->key_len;
+
+                if (ctx->cipher->ctx_size != 0) {
+                        ctx->cipher_data = calloc(1, ctx->cipher->ctx_size);
+                        if (ctx->cipher_data == NULL) {
+                                EVPerror(ERR_R_MALLOC_FAILURE);
+                                return 0;
+                        }
+                }
+
+                if ((ctx->cipher->flags & EVP_CIPH_CTRL_INIT) != 0) {
+                        if (!EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_INIT, 0, NULL)) {
+                                EVPerror(EVP_R_INITIALIZATION_ERROR);
+                                return 0;
+                        }
+                }
+        }
+
+        /* Block sizes must be a power of 2 due to the use of block_mask. */
+        if (ctx->cipher->block_size != 1 &&
+            ctx->cipher->block_size != 8 &&
+            ctx->cipher->block_size != 16) {
+                EVPerror(EVP_R_BAD_BLOCK_LENGTH);
+                return 0;
+        }
+
+        if ((ctx->flags & EVP_CIPHER_CTX_FLAG_WRAP_ALLOW) == 0 &&
+            EVP_CIPHER_CTX_mode(ctx) == EVP_CIPH_WRAP_MODE) {
+                EVPerror(EVP_R_WRAP_MODE_NOT_ALLOWED);
+                return 0;
+        }
+
+        if ((EVP_CIPHER_CTX_flags(ctx) & EVP_CIPH_CUSTOM_IV) == 0) {
+                int iv_len;
+
+                switch (EVP_CIPHER_CTX_mode(ctx)) {
+
+                case EVP_CIPH_STREAM_CIPHER:
+                case EVP_CIPH_ECB_MODE:
+                        break;
+
+                case EVP_CIPH_CFB_MODE:
+                case EVP_CIPH_OFB_MODE:
+
+                        ctx->num = 0;
+                        /* fall-through */
+
+                case EVP_CIPH_CBC_MODE:
+                        iv_len = EVP_CIPHER_CTX_iv_length(ctx);
+                        if (iv_len < 0 || iv_len > sizeof(ctx->oiv)) {
+                                EVPerror(EVP_R_IV_TOO_LARGE);
+                                return 0;
+                        }
+                        if (iv != NULL)
+                                memcpy(ctx->oiv, iv, iv_len);
+                        memcpy(ctx->iv, ctx->oiv, iv_len);
+                        break;
+
+                case EVP_CIPH_CTR_MODE:
+                        ctx->num = 0;
+                        iv_len = EVP_CIPHER_CTX_iv_length(ctx);
+                        if (iv_len < 0 || iv_len > sizeof(ctx->iv)) {
+                                EVPerror(EVP_R_IV_TOO_LARGE);
+                                return 0;
+                        }
+                        /* Don't reuse IV for CTR mode */
+                        if (iv != NULL)
+                                memcpy(ctx->iv, iv, iv_len);
+                        break;
+
+                default:
+                        return 0;
+                        break;
+                }
+        }
+
+        if (key != NULL || (ctx->cipher->flags & EVP_CIPH_ALWAYS_CALL_INIT) != 0) {
+                if (!ctx->cipher->init(ctx, key, iv, enc))
+                        return 0;
+        }
+
+        ctx->partial_len = 0;
+        ctx->final_used = 0;
+
+        return 1;
+}
+
+int
+EVP_CipherUpdate(EVP_CIPHER_CTX *ctx, unsigned char *out, int *out_len,
+    const unsigned char *in, int in_len)
+{
+        if (ctx->encrypt)
+                return EVP_EncryptUpdate(ctx, out, out_len, in, in_len);
+
+        return EVP_DecryptUpdate(ctx, out, out_len, in, in_len);
+}
+
+int
+EVP_CipherFinal(EVP_CIPHER_CTX *ctx, unsigned char *out, int *out_len)
+{
+        if (ctx->encrypt)
+                return EVP_EncryptFinal_ex(ctx, out, out_len);
+
+        return EVP_DecryptFinal_ex(ctx, out, out_len);
+}
+
+int
+EVP_CipherFinal_ex(EVP_CIPHER_CTX *ctx, unsigned char *out, int *out_len)
+{
+        if (ctx->encrypt)
+                return EVP_EncryptFinal_ex(ctx, out, out_len);
+
+        return EVP_DecryptFinal_ex(ctx, out, out_len);
+}
+
+int
+EVP_EncryptInit(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *cipher,
+    const unsigned char *key, const unsigned char *iv)
+{
+        return EVP_CipherInit(ctx, cipher, key, iv, 1);
+}
+
+int
+EVP_EncryptInit_ex(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *cipher, ENGINE *engine,
+    const unsigned char *key, const unsigned char *iv)
+{
+        return EVP_CipherInit_ex(ctx, cipher, NULL, key, iv, 1);
+}
+
+/*
+ * EVP_Cipher() is an implementation detail of EVP_Cipher{Update,Final}().
+ * Behavior depends on EVP_CIPH_FLAG_CUSTOM_CIPHER being set on ctx->cipher.
+ *
+ * If the flag is set, do_cipher() operates in update mode if in != NULL and
+ * in final mode if in == NULL. It returns the number of bytes written to out
+ * (which may be 0) or -1 on error.
+ *
+ * If the flag is not set, do_cipher() assumes properly aligned data and that
+ * padding is handled correctly by the caller. Most do_cipher() methods will
+ * silently produce garbage and succeed. Returns 1 on success, 0 on error.
+ */
+int
+EVP_Cipher(EVP_CIPHER_CTX *ctx, unsigned char *out, const unsigned char *in,
+    unsigned int in_len)
+{
+        return ctx->cipher->do_cipher(ctx, out, in, in_len);
+}
+
+static int
+evp_cipher(EVP_CIPHER_CTX *ctx, unsigned char *out, int *out_len,
+    const unsigned char *in, int in_len)
+{
+        int len;
+
+        *out_len = 0;
+
+        if (in_len < 0)
+                return 0;
+
+        if ((ctx->cipher->flags & EVP_CIPH_FLAG_CUSTOM_CIPHER) != 0) {
+                if ((len = ctx->cipher->do_cipher(ctx, out, in, in_len)) < 0)
+                        return 0;
+
+                *out_len = len;
+                return 1;
+        }
+
+        if (!ctx->cipher->do_cipher(ctx, out, in, in_len))
+                return 0;
+
+        *out_len = in_len;
+
+        return 1;
+}
+
+int
+EVP_EncryptUpdate(EVP_CIPHER_CTX *ctx, unsigned char *out, int *out_len,
+    const unsigned char *in, int in_len)
+{
+        const int block_size = ctx->cipher->block_size;
+        const int block_mask = block_size - 1;
+        int partial_len = ctx->partial_len;
+        int len = 0, total_len = 0;
+
+        *out_len = 0;
+
+        if ((block_size & block_mask) != 0)
+                return 0;
+
+        if (in_len < 0)
+                return 0;
+
+        if (in_len == 0 && EVP_CIPHER_mode(ctx->cipher) != EVP_CIPH_CCM_MODE)
+                return 1;
+
+        if ((ctx->cipher->flags & EVP_CIPH_FLAG_CUSTOM_CIPHER) != 0)
+                return evp_cipher(ctx, out, out_len, in, in_len);
+
+        if (partial_len == 0 && (in_len & block_mask) == 0)
+                return evp_cipher(ctx, out, out_len, in, in_len);
+
+        if (partial_len < 0 || partial_len >= block_size ||
+            block_size > sizeof(ctx->buf)) {
+                EVPerror(EVP_R_BAD_BLOCK_LENGTH);
+                return 0;
+        }
+
+        if (partial_len > 0) {
+                int partial_needed;
+
+                if ((partial_needed = block_size - partial_len) > in_len) {
+                        memcpy(&ctx->buf[partial_len], in, in_len);
+                        ctx->partial_len += in_len;
+                        return 1;
+                }
+
+                /*
+                 * Once the first partial_needed bytes from in are processed,
+                 * the number of multiples of block_size of data remaining is
+                 * (in_len - partial_needed) & ~block_mask.  Ensure that this
+                 * plus the block processed from ctx->buf doesn't overflow.
+                 */
+                if (((in_len - partial_needed) & ~block_mask) > INT_MAX - block_size) {
+                        EVPerror(EVP_R_TOO_LARGE);
+                        return 0;
+                }
+                memcpy(&ctx->buf[partial_len], in, partial_needed);
+
+                len = 0;
+                if (!evp_cipher(ctx, out, &len, ctx->buf, block_size))
+                        return 0;
+                total_len = len;
+
+                in_len -= partial_needed;
+                in += partial_needed;
+                out += len;
+        }
+
+        partial_len = in_len & block_mask;
+        if ((in_len -= partial_len) > 0) {
+                if (INT_MAX - in_len < total_len)
+                        return 0;
+                len = 0;
+                if (!evp_cipher(ctx, out, &len, in, in_len))
+                        return 0;
+                if (INT_MAX - len < total_len)
+                        return 0;
+                total_len += len;
+        }
+
+        if ((ctx->partial_len = partial_len) > 0)
+                memcpy(ctx->buf, &in[in_len], partial_len);
+
+        *out_len = total_len;
+
+        return 1;
+}
+
+int
+EVP_EncryptFinal(EVP_CIPHER_CTX *ctx, unsigned char *out, int *out_len)
+{
+        return EVP_EncryptFinal_ex(ctx, out, out_len);
+}
+
+int
+EVP_EncryptFinal_ex(EVP_CIPHER_CTX *ctx, unsigned char *out, int *out_len)
+{
+        const int block_size = ctx->cipher->block_size;
+        int partial_len = ctx->partial_len;
+        int pad;
+
+        *out_len = 0;
+
+        if ((ctx->cipher->flags & EVP_CIPH_FLAG_CUSTOM_CIPHER) != 0)
+                return evp_cipher(ctx, out, out_len, NULL, 0);
+
+        if (partial_len < 0 || partial_len >= block_size ||
+            block_size > sizeof(ctx->buf)) {
+                EVPerror(EVP_R_BAD_BLOCK_LENGTH);
+                return 0;
+        }
+        if (block_size == 1)
+                return 1;
+
+        if ((ctx->flags & EVP_CIPH_NO_PADDING) != 0) {
+                if (partial_len != 0) {
+                        EVPerror(EVP_R_DATA_NOT_MULTIPLE_OF_BLOCK_LENGTH);
+                        return 0;
+                }
+                return 1;
+        }
+
+        pad = block_size - partial_len;
+        memset(&ctx->buf[partial_len], pad, pad);
+
+        return evp_cipher(ctx, out, out_len, ctx->buf, block_size);
+}
+
+int
+EVP_DecryptInit(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *cipher,
+    const unsigned char *key, const unsigned char *iv)
+{
+        return EVP_CipherInit(ctx, cipher, key, iv, 0);
+}
+
+int
+EVP_DecryptInit_ex(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *cipher, ENGINE *engine,
+    const unsigned char *key, const unsigned char *iv)
+{
+        return EVP_CipherInit_ex(ctx, cipher, NULL, key, iv, 0);
+}
+
+int
+EVP_DecryptUpdate(EVP_CIPHER_CTX *ctx, unsigned char *out, int *out_len,
+    const unsigned char *in, int in_len)
+{
+        const int block_size = ctx->cipher->block_size;
+        const int block_mask = block_size - 1;
+        int len = 0, total_len = 0;
+
+        *out_len = 0;
+
+        if ((block_size & block_mask) != 0)
+                return 0;
+
+        if (in_len < 0)
+                return 0;
+
+        if (in_len == 0 && EVP_CIPHER_mode(ctx->cipher) != EVP_CIPH_CCM_MODE)
+                return 1;
+
+        if ((ctx->cipher->flags & EVP_CIPH_FLAG_CUSTOM_CIPHER) != 0)
+                return evp_cipher(ctx, out, out_len, in, in_len);
+
+        if ((ctx->flags & EVP_CIPH_NO_PADDING) != 0)
+                return EVP_EncryptUpdate(ctx, out, out_len, in, in_len);
+
+        if (block_size > sizeof(ctx->final)) {
+                EVPerror(EVP_R_BAD_BLOCK_LENGTH);
+                return 0;
+        }
+
+        if (ctx->final_used) {
+                /*
+                 * final_used is only set if partial_len is 0. Therefore the
+                 * output from EVP_EncryptUpdate() is in_len & ~block_mask.
+                 * Ensure (in_len & ~block_mask) + block_size doesn't overflow.
+                 */
+                if ((in_len & ~block_mask) > INT_MAX - block_size) {
+                        EVPerror(EVP_R_TOO_LARGE);
+                        return 0;
+                }
+                memcpy(out, ctx->final, block_size);
+                out += block_size;
+                total_len = block_size;
+        }
+
+        ctx->final_used = 0;
+
+        len = 0;
+        if (!EVP_EncryptUpdate(ctx, out, &len, in, in_len))
+                return 0;
+
+        /* Keep copy of last block if a multiple of block_size was decrypted. */
+        if (block_size > 1 && ctx->partial_len == 0) {
+                if (len < block_size)
+                        return 0;
+                len -= block_size;
+                memcpy(ctx->final, &out[len], block_size);
+                ctx->final_used = 1;
+        }
+
+        if (len > INT_MAX - total_len)
+                return 0;
+        total_len += len;
+
+        *out_len = total_len;
+
+        return 1;
+}
+
+int
+EVP_DecryptFinal(EVP_CIPHER_CTX *ctx, unsigned char *out, int *out_len)
+{
+        return EVP_DecryptFinal_ex(ctx, out, out_len);
+}
+
+int
+EVP_DecryptFinal_ex(EVP_CIPHER_CTX *ctx, unsigned char *out, int *out_len)
+{
+        const int block_size = ctx->cipher->block_size;
+        int partial_len = ctx->partial_len;
+        int i, pad, plain_len;
+
+        *out_len = 0;
+
+        if ((ctx->cipher->flags & EVP_CIPH_FLAG_CUSTOM_CIPHER) != 0)
+                return evp_cipher(ctx, out, out_len, NULL, 0);
+
+        if ((ctx->flags & EVP_CIPH_NO_PADDING) != 0) {
+                if (partial_len != 0) {
+                        EVPerror(EVP_R_DATA_NOT_MULTIPLE_OF_BLOCK_LENGTH);
+                        return 0;
+                }
+                return 1;
+        }
+
+        if (block_size == 1)
+                return 1;
+
+        if (partial_len != 0 || !ctx->final_used) {
+                EVPerror(EVP_R_WRONG_FINAL_BLOCK_LENGTH);
+                return 0;
+        }
+
+        if (block_size > sizeof(ctx->final)) {
+                EVPerror(EVP_R_BAD_BLOCK_LENGTH);
+                return 0;
+        }
+
+        pad = ctx->final[block_size - 1];
+        if (pad <= 0 || pad > block_size) {
+                EVPerror(EVP_R_BAD_DECRYPT);
+                return 0;
+        }
+        plain_len = block_size - pad;
+        for (i = plain_len; i < block_size; i++) {
+                if (ctx->final[i] != pad) {
+                        EVPerror(EVP_R_BAD_DECRYPT);
+                        return 0;
+                }
+        }
+
+        memcpy(out, ctx->final, plain_len);
+        *out_len = plain_len;
+
+        return 1;
+}
+
+EVP_CIPHER_CTX *
+EVP_CIPHER_CTX_new(void)
+{
+        return calloc(1, sizeof(EVP_CIPHER_CTX));
+}
+
+void
+EVP_CIPHER_CTX_free(EVP_CIPHER_CTX *ctx)
+{
+        if (ctx == NULL)
+                return;
+
+        EVP_CIPHER_CTX_cleanup(ctx);
+
+        free(ctx);
+}
+
+void
+EVP_CIPHER_CTX_init(EVP_CIPHER_CTX *ctx)
+{
+        memset(ctx, 0, sizeof(EVP_CIPHER_CTX));
+}
+
+int
+EVP_CIPHER_CTX_reset(EVP_CIPHER_CTX *a)
+{
+        return EVP_CIPHER_CTX_cleanup(a);
+}
+
+int
+EVP_CIPHER_CTX_cleanup(EVP_CIPHER_CTX *c)
+{
+        if (c->cipher != NULL) {
+                /* XXX - Avoid leaks, so ignore return value of cleanup()... */
+                if (c->cipher->cleanup != NULL)
+                        c->cipher->cleanup(c);
+                if (c->cipher_data != NULL)
+                        explicit_bzero(c->cipher_data, c->cipher->ctx_size);
+        }
+
+        /* XXX - store size of cipher_data so we can always freezero(). */
+        free(c->cipher_data);
+
+        explicit_bzero(c, sizeof(EVP_CIPHER_CTX));
+
+        return 1;
+}
+
+int
+EVP_CIPHER_CTX_set_key_length(EVP_CIPHER_CTX *c, int keylen)
+{
+        if (c->cipher->flags & EVP_CIPH_CUSTOM_KEY_LENGTH)
+                return EVP_CIPHER_CTX_ctrl(c, EVP_CTRL_SET_KEY_LENGTH,
+                    keylen, NULL);
+        if (c->key_len == keylen)
+                return 1;
+        if (keylen > 0 && (c->cipher->flags & EVP_CIPH_VARIABLE_LENGTH)) {
+                c->key_len = keylen;
+                return 1;
+        }
+        EVPerror(EVP_R_INVALID_KEY_LENGTH);
+        return 0;
+}
+
+int
+EVP_CIPHER_CTX_set_padding(EVP_CIPHER_CTX *ctx, int pad)
+{
+        if (pad)
+                ctx->flags &= ~EVP_CIPH_NO_PADDING;
+        else
+                ctx->flags |= EVP_CIPH_NO_PADDING;
+        return 1;
+}
+
+int
+EVP_CIPHER_CTX_ctrl(EVP_CIPHER_CTX *ctx, int type, int arg, void *ptr)
+{
+        int ret;
+
+        if (!ctx->cipher) {
+                EVPerror(EVP_R_NO_CIPHER_SET);
+                return 0;
+        }
+
+        if (!ctx->cipher->ctrl) {
+                EVPerror(EVP_R_CTRL_NOT_IMPLEMENTED);
+                return 0;
+        }
+
+        ret = ctx->cipher->ctrl(ctx, type, arg, ptr);
+        if (ret == -1) {
+                EVPerror(EVP_R_CTRL_OPERATION_NOT_IMPLEMENTED);
+                return 0;
+        }
+        return ret;
+}
+
+int
+EVP_CIPHER_CTX_rand_key(EVP_CIPHER_CTX *ctx, unsigned char *key)
+{
+        if (ctx->cipher->flags & EVP_CIPH_RAND_KEY)
+                return EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_RAND_KEY, 0, key);
+        arc4random_buf(key, ctx->key_len);
+        return 1;
+}
+
+int
+EVP_CIPHER_CTX_copy(EVP_CIPHER_CTX *out, const EVP_CIPHER_CTX *in)
+{
+        if (in == NULL || in->cipher == NULL) {
+                EVPerror(EVP_R_INPUT_NOT_INITIALIZED);
+                return 0;
+        }
+
+        EVP_CIPHER_CTX_cleanup(out);
+        memcpy(out, in, sizeof *out);
+
+        if (in->cipher_data && in->cipher->ctx_size) {
+                out->cipher_data = calloc(1, in->cipher->ctx_size);
+                if (out->cipher_data == NULL) {
+                        EVPerror(ERR_R_MALLOC_FAILURE);
+                        return 0;
+                }
+                memcpy(out->cipher_data, in->cipher_data, in->cipher->ctx_size);
+        }
+
+        if (in->cipher->flags & EVP_CIPH_CUSTOM_COPY) {
+                if (!in->cipher->ctrl((EVP_CIPHER_CTX *)in, EVP_CTRL_COPY,
+                    0, out)) {
+                        /*
+                         * If the custom copy control failed, assume that there
+                         * may still be pointers copied in the cipher_data that
+                         * we do not own. This may result in a leak from a bad
+                         * custom copy control, but that's preferable to a
+                         * double free...
+                         */
+                        freezero(out->cipher_data, in->cipher->ctx_size);
+                        out->cipher_data = NULL;
+                        return 0;
+                }
+        }
+
+        return 1;
+}