1/*
2 * Copyright 2019-2020 The OpenSSL Project Authors. All Rights Reserved.
3 *
4 * Licensed under the Apache License 2.0 (the "License").  You may not use
5 * this file except in compliance with the License.  You can obtain a copy
6 * in the file LICENSE in the source distribution or at
7 * https://www.openssl.org/source/license.html
8 */
9
10/* RC4_HMAC_MD5 cipher implementation */
11
12/*
13 * MD5 and RC4 low level APIs are deprecated for public use, but still ok for
14 * internal use.
15 */
16#include "internal/deprecated.h"
17
18#include "cipher_rc4_hmac_md5.h"
19
20#define NO_PAYLOAD_LENGTH ((size_t)-1)
21
22#if defined(RC4_ASM)                                                           \
23    && defined(MD5_ASM)                                                        \
24    && (defined(__x86_64)                                                      \
25        || defined(__x86_64__)                                                 \
26        || defined(_M_AMD64)                                                   \
27        || defined(_M_X64))
28# define STITCHED_CALL
29# define MOD 32 /* 32 is $MOD from rc4_md5-x86_64.pl */
30#else
31# define rc4_off 0
32# define md5_off 0
33#endif
34
35static int cipher_hw_rc4_hmac_md5_initkey(PROV_CIPHER_CTX *bctx,
36                                          const uint8_t *key, size_t keylen)
37{
38    PROV_RC4_HMAC_MD5_CTX *ctx = (PROV_RC4_HMAC_MD5_CTX *)bctx;
39
40    RC4_set_key(&ctx->ks.ks, keylen, key);
41    MD5_Init(&ctx->head);       /* handy when benchmarking */
42    ctx->tail = ctx->head;
43    ctx->md = ctx->head;
44    ctx->payload_length = NO_PAYLOAD_LENGTH;
45    bctx->removetlsfixed = MD5_DIGEST_LENGTH;
46    return 1;
47}
48
49static int cipher_hw_rc4_hmac_md5_cipher(PROV_CIPHER_CTX *bctx,
50                                         unsigned char *out,
51                                         const unsigned char *in, size_t len)
52{
53    PROV_RC4_HMAC_MD5_CTX *ctx = (PROV_RC4_HMAC_MD5_CTX *)bctx;
54    RC4_KEY *ks = &ctx->ks.ks;
55
56#if defined(STITCHED_CALL)
57    size_t rc4_off = MOD - 1 - (ks->x & (MOD - 1));
58    size_t md5_off = MD5_CBLOCK - ctx->md.num, blocks;
59    unsigned int l;
60#endif
61    size_t plen = ctx->payload_length;
62
63    if (plen != NO_PAYLOAD_LENGTH && len != (plen + MD5_DIGEST_LENGTH))
64        return 0;
65
66    if (ctx->base.enc) {
67        if (plen == NO_PAYLOAD_LENGTH)
68            plen = len;
69#if defined(STITCHED_CALL)
70        /* cipher has to "fall behind" */
71        if (rc4_off > md5_off)
72            md5_off += MD5_CBLOCK;
73
74        if (plen > md5_off
75                && (blocks = (plen - md5_off) / MD5_CBLOCK)
76                && (OPENSSL_ia32cap_P[0] & (1 << 20)) == 0) {
77            MD5_Update(&ctx->md, in, md5_off);
78            RC4(ks, rc4_off, in, out);
79
80            rc4_md5_enc(ks, in + rc4_off, out + rc4_off,
81                        &ctx->md, in + md5_off, blocks);
82            blocks *= MD5_CBLOCK;
83            rc4_off += blocks;
84            md5_off += blocks;
85            ctx->md.Nh += blocks >> 29;
86            ctx->md.Nl += blocks <<= 3;
87            if (ctx->md.Nl < (unsigned int)blocks)
88                ctx->md.Nh++;
89        } else {
90            rc4_off = 0;
91            md5_off = 0;
92        }
93#endif
94        MD5_Update(&ctx->md, in + md5_off, plen - md5_off);
95
96        if (plen != len) {      /* "TLS" mode of operation */
97            if (in != out)
98                memcpy(out + rc4_off, in + rc4_off, plen - rc4_off);
99
100            /* calculate HMAC and append it to payload */
101            MD5_Final(out + plen, &ctx->md);
102            ctx->md = ctx->tail;
103            MD5_Update(&ctx->md, out + plen, MD5_DIGEST_LENGTH);
104            MD5_Final(out + plen, &ctx->md);
105            /* encrypt HMAC at once */
106            RC4(ks, len - rc4_off, out + rc4_off, out + rc4_off);
107        } else {
108            RC4(ks, len - rc4_off, in + rc4_off, out + rc4_off);
109        }
110    } else {
111        unsigned char mac[MD5_DIGEST_LENGTH];
112
113#if defined(STITCHED_CALL)
114        /* digest has to "fall behind" */
115        if (md5_off > rc4_off)
116            rc4_off += 2 * MD5_CBLOCK;
117        else
118            rc4_off += MD5_CBLOCK;
119
120        if (len > rc4_off
121                && (blocks = (len - rc4_off) / MD5_CBLOCK)
122                && (OPENSSL_ia32cap_P[0] & (1 << 20)) == 0) {
123            RC4(ks, rc4_off, in, out);
124            MD5_Update(&ctx->md, out, md5_off);
125
126            rc4_md5_enc(ks, in + rc4_off, out + rc4_off,
127                        &ctx->md, out + md5_off, blocks);
128            blocks *= MD5_CBLOCK;
129            rc4_off += blocks;
130            md5_off += blocks;
131            l = (ctx->md.Nl + (blocks << 3)) & 0xffffffffU;
132            if (l < ctx->md.Nl)
133                ctx->md.Nh++;
134            ctx->md.Nl = l;
135            ctx->md.Nh += blocks >> 29;
136        } else {
137            md5_off = 0;
138            rc4_off = 0;
139        }
140#endif
141        /* decrypt HMAC at once */
142        RC4(ks, len - rc4_off, in + rc4_off, out + rc4_off);
143        if (plen != NO_PAYLOAD_LENGTH) {
144            /* "TLS" mode of operation */
145            MD5_Update(&ctx->md, out + md5_off, plen - md5_off);
146
147            /* calculate HMAC and verify it */
148            MD5_Final(mac, &ctx->md);
149            ctx->md = ctx->tail;
150            MD5_Update(&ctx->md, mac, MD5_DIGEST_LENGTH);
151            MD5_Final(mac, &ctx->md);
152
153            if (CRYPTO_memcmp(out + plen, mac, MD5_DIGEST_LENGTH))
154                return 0;
155        } else {
156            MD5_Update(&ctx->md, out + md5_off, len - md5_off);
157        }
158    }
159
160    ctx->payload_length = NO_PAYLOAD_LENGTH;
161
162    return 1;
163}
164
165static int cipher_hw_rc4_hmac_md5_tls_init(PROV_CIPHER_CTX *bctx,
166                                           unsigned char *aad, size_t aad_len)
167{
168    PROV_RC4_HMAC_MD5_CTX *ctx = (PROV_RC4_HMAC_MD5_CTX *)bctx;
169    unsigned int len;
170
171    if (aad_len != EVP_AEAD_TLS1_AAD_LEN)
172        return 0;
173
174    len = aad[aad_len - 2] << 8 | aad[aad_len - 1];
175
176    if (!bctx->enc) {
177        if (len < MD5_DIGEST_LENGTH)
178            return 0;
179        len -= MD5_DIGEST_LENGTH;
180        aad[aad_len - 2] = len >> 8;
181        aad[aad_len - 1] = len;
182    }
183    ctx->payload_length = len;
184    ctx->md = ctx->head;
185    MD5_Update(&ctx->md, aad, aad_len);
186
187    return MD5_DIGEST_LENGTH;
188}
189
190static void cipher_hw_rc4_hmac_md5_init_mackey(PROV_CIPHER_CTX *bctx,
191                                               const unsigned char *key,
192                                               size_t len)
193{
194    PROV_RC4_HMAC_MD5_CTX *ctx = (PROV_RC4_HMAC_MD5_CTX *)bctx;
195    unsigned int i;
196    unsigned char hmac_key[64];
197
198    memset(hmac_key, 0, sizeof(hmac_key));
199
200    if (len > (int)sizeof(hmac_key)) {
201        MD5_Init(&ctx->head);
202        MD5_Update(&ctx->head, key, len);
203        MD5_Final(hmac_key, &ctx->head);
204    } else {
205        memcpy(hmac_key, key, len);
206    }
207
208    for (i = 0; i < sizeof(hmac_key); i++)
209        hmac_key[i] ^= 0x36; /* ipad */
210    MD5_Init(&ctx->head);
211    MD5_Update(&ctx->head, hmac_key, sizeof(hmac_key));
212
213    for (i = 0; i < sizeof(hmac_key); i++)
214        hmac_key[i] ^= 0x36 ^ 0x5c; /* opad */
215    MD5_Init(&ctx->tail);
216    MD5_Update(&ctx->tail, hmac_key, sizeof(hmac_key));
217
218    OPENSSL_cleanse(hmac_key, sizeof(hmac_key));
219}
220
221static const PROV_CIPHER_HW_RC4_HMAC_MD5 rc4_hmac_md5_hw = {
222    {
223      cipher_hw_rc4_hmac_md5_initkey,
224      cipher_hw_rc4_hmac_md5_cipher
225    },
226    cipher_hw_rc4_hmac_md5_tls_init,
227    cipher_hw_rc4_hmac_md5_init_mackey
228};
229
230const PROV_CIPHER_HW *ossl_prov_cipher_hw_rc4_hmac_md5(size_t keybits)
231{
232    return (PROV_CIPHER_HW *)&rc4_hmac_md5_hw;
233}
234