/* $OpenBSD: e_rc4_hmac_md5.c,v 1.9 2021/12/12 21:30:13 tb Exp $ */
/* ====================================================================
 * Copyright (c) 2011 The OpenSSL Project.  All rights reserved.
 *
 * 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 above 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 acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
 *
 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
 *    endorse or promote products derived from this software without
 *    prior written permission. For written permission, please contact
 *    licensing@OpenSSL.org.
 *
 * 5. Products derived from this software may not be called "OpenSSL"
 *    nor may "OpenSSL" appear in their names without prior written
 *    permission of the OpenSSL Project.
 *
 * 6. Redistributions of any form whatsoever must retain the following
 *    acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
 *
 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
 * EXPRESSED 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 OpenSSL PROJECT OR
 * ITS 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.
 * ====================================================================
 */

#include <stdio.h>
#include <string.h>

#include <openssl/opensslconf.h>

#if !defined(OPENSSL_NO_RC4) && !defined(OPENSSL_NO_MD5)

#include <openssl/evp.h>
#include <openssl/objects.h>
#include <openssl/rc4.h>
#include <openssl/md5.h>

#include "evp_locl.h"

/* FIXME: surely this is available elsewhere? */
#define EVP_RC4_KEY_SIZE                16

typedef struct {
        RC4_KEY         ks;
        MD5_CTX         head, tail, md;
        size_t          payload_length;
} EVP_RC4_HMAC_MD5;

#define NO_PAYLOAD_LENGTH       ((size_t)-1)

void rc4_md5_enc (RC4_KEY *key, const void *in0, void *out,
    MD5_CTX *ctx, const void *inp, size_t blocks);

#define data(ctx) ((EVP_RC4_HMAC_MD5 *)(ctx)->cipher_data)

static int
rc4_hmac_md5_init_key(EVP_CIPHER_CTX *ctx, const unsigned char *inkey,
    const unsigned char *iv, int enc)
{
        EVP_RC4_HMAC_MD5 *key = data(ctx);

        RC4_set_key(&key->ks, EVP_CIPHER_CTX_key_length(ctx), inkey);

        MD5_Init(&key->head);   /* handy when benchmarking */
        key->tail = key->head;
        key->md = key->head;

        key->payload_length = NO_PAYLOAD_LENGTH;

        return 1;
}

#if     !defined(OPENSSL_NO_ASM) && defined(RC4_MD5_ASM) &&     ( \
        defined(__x86_64)       || defined(__x86_64__)  || \
        defined(_M_AMD64)       || defined(_M_X64)      || \
        defined(__INTEL__)              ) && \
        !(defined(__APPLE__) && defined(__MACH__))
#define STITCHED_CALL
#include "x86_arch.h"
#endif

#if !defined(STITCHED_CALL)
#define rc4_off 0
#define md5_off 0
#endif

static int
rc4_hmac_md5_cipher(EVP_CIPHER_CTX *ctx, unsigned char *out,
    const unsigned char *in, size_t len)
{
        EVP_RC4_HMAC_MD5 *key = data(ctx);
#if defined(STITCHED_CALL)
        size_t  rc4_off = 32-1-(key->ks.x&(32-1)),      /* 32 is $MOD from rc4_md5-x86_64.pl */
        md5_off = MD5_CBLOCK - key->md.num,
            blocks;
        unsigned int l;
#endif
        size_t  plen = key->payload_length;

        if (plen != NO_PAYLOAD_LENGTH && len != (plen + MD5_DIGEST_LENGTH))
                return 0;

        if (ctx->encrypt) {
                if (plen == NO_PAYLOAD_LENGTH)
                        plen = len;
#if defined(STITCHED_CALL)
                /* cipher has to "fall behind" */
                if (rc4_off > md5_off)
                        md5_off += MD5_CBLOCK;

                if (plen > md5_off &&
                    (blocks = (plen - md5_off) / MD5_CBLOCK) &&
                    (OPENSSL_cpu_caps() & CPUCAP_MASK_INTELP4) == 0) {
                        MD5_Update(&key->md, in, md5_off);
                        RC4(&key->ks, rc4_off, in, out);

                        rc4_md5_enc(&key->ks, in + rc4_off, out + rc4_off,
                            &key->md, in + md5_off, blocks);
                        blocks *= MD5_CBLOCK;
                        rc4_off += blocks;
                        md5_off += blocks;
                        key->md.Nh += blocks >> 29;
                        key->md.Nl += blocks <<= 3;
                        if (key->md.Nl < (unsigned int)blocks)
                                key->md.Nh++;
                } else {
                        rc4_off = 0;
                        md5_off = 0;
                }
#endif
                MD5_Update(&key->md, in + md5_off, plen - md5_off);

                if (plen!=len) {        /* "TLS" mode of operation */
                        if (in != out)
                                memcpy(out + rc4_off, in + rc4_off,
                                    plen - rc4_off);

                        /* calculate HMAC and append it to payload */
                        MD5_Final(out + plen, &key->md);
                        key->md = key->tail;
                        MD5_Update(&key->md, out + plen, MD5_DIGEST_LENGTH);
                        MD5_Final(out + plen, &key->md);

                        /* encrypt HMAC at once */
                        RC4(&key->ks, len - rc4_off, out + rc4_off,
                            out + rc4_off);
                } else {
                        RC4(&key->ks, len - rc4_off, in + rc4_off,
                            out + rc4_off);
                }
        } else {
                unsigned char mac[MD5_DIGEST_LENGTH];
#if defined(STITCHED_CALL)
                /* digest has to "fall behind" */
                if (md5_off > rc4_off)
                        rc4_off += 2*MD5_CBLOCK;
                else
                        rc4_off += MD5_CBLOCK;

                if (len > rc4_off && (blocks = (len - rc4_off) / MD5_CBLOCK) &&
                    (OPENSSL_cpu_caps() & CPUCAP_MASK_INTELP4) == 0) {
                        RC4(&key->ks, rc4_off, in, out);
                        MD5_Update(&key->md, out, md5_off);

                        rc4_md5_enc(&key->ks, in + rc4_off, out + rc4_off,
                            &key->md, out + md5_off, blocks);
                        blocks *= MD5_CBLOCK;
                        rc4_off += blocks;
                        md5_off += blocks;
                        l = (key->md.Nl + (blocks << 3)) & 0xffffffffU;
                        if (l < key->md.Nl)
                                key->md.Nh++;
                        key->md.Nl = l;
                        key->md.Nh += blocks >> 29;
                } else {
                        md5_off = 0;
                        rc4_off = 0;
                }
#endif
                /* decrypt HMAC at once */
                RC4(&key->ks, len - rc4_off, in + rc4_off, out + rc4_off);
                if (plen!=NO_PAYLOAD_LENGTH) {  /* "TLS" mode of operation */
                        MD5_Update(&key->md, out + md5_off, plen - md5_off);

                        /* calculate HMAC and verify it */
                        MD5_Final(mac, &key->md);
                        key->md = key->tail;
                        MD5_Update(&key->md, mac, MD5_DIGEST_LENGTH);
                        MD5_Final(mac, &key->md);

                        if (memcmp(out + plen, mac, MD5_DIGEST_LENGTH))
                                return 0;
                } else {
                        MD5_Update(&key->md, out + md5_off, len - md5_off);
                }
        }

        key->payload_length = NO_PAYLOAD_LENGTH;

        return 1;
}

static int
rc4_hmac_md5_ctrl(EVP_CIPHER_CTX *ctx, int type, int arg, void *ptr)
{
        EVP_RC4_HMAC_MD5 *key = data(ctx);

        switch (type) {
        case EVP_CTRL_AEAD_SET_MAC_KEY:
                {
                        unsigned int  i;
                        unsigned char hmac_key[64];

                        memset (hmac_key, 0, sizeof(hmac_key));

                        if (arg > (int)sizeof(hmac_key)) {
                                MD5_Init(&key->head);
                                MD5_Update(&key->head, ptr, arg);
                                MD5_Final(hmac_key, &key->head);
                        } else {
                                memcpy(hmac_key, ptr, arg);
                        }

                        for (i = 0; i < sizeof(hmac_key); i++)
                                hmac_key[i] ^= 0x36;            /* ipad */
                        MD5_Init(&key->head);
                        MD5_Update(&key->head, hmac_key, sizeof(hmac_key));

                        for (i = 0; i < sizeof(hmac_key); i++)
                                hmac_key[i] ^= 0x36 ^ 0x5c;     /* opad */
                        MD5_Init(&key->tail);
                        MD5_Update(&key->tail, hmac_key, sizeof(hmac_key));

                        return 1;
                }
        case EVP_CTRL_AEAD_TLS1_AAD:
                {
                        unsigned char *p = ptr;
                        unsigned int len = p[arg - 2] << 8 | p[arg - 1];

                        if (!ctx->encrypt) {
                                if (len < MD5_DIGEST_LENGTH)
                                        return -1;
                                len -= MD5_DIGEST_LENGTH;
                                p[arg - 2] = len >> 8;
                                p[arg - 1] = len;
                        }
                        key->payload_length = len;
                        key->md = key->head;
                        MD5_Update(&key->md, p, arg);

                        return MD5_DIGEST_LENGTH;
                }
        default:
                return -1;
        }
}

static EVP_CIPHER r4_hmac_md5_cipher = {
#ifdef NID_rc4_hmac_md5
        NID_rc4_hmac_md5,
#else
        NID_undef,
#endif
        1, EVP_RC4_KEY_SIZE, 0,
        EVP_CIPH_STREAM_CIPHER|EVP_CIPH_VARIABLE_LENGTH|EVP_CIPH_FLAG_AEAD_CIPHER,
        rc4_hmac_md5_init_key,
        rc4_hmac_md5_cipher,
        NULL,
        sizeof(EVP_RC4_HMAC_MD5),
        NULL,
        NULL,
        rc4_hmac_md5_ctrl,
        NULL
};

const EVP_CIPHER *
EVP_rc4_hmac_md5(void)
{
        return (&r4_hmac_md5_cipher);
}
#endif