1/*
2 * Copyright 2011-2021 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/*
11 * MD5 and RC4 low level APIs are deprecated for public use, but still ok for
12 * internal use.
13 */
14#include "internal/deprecated.h"
15
16#include "internal/cryptlib.h"
17#include <openssl/opensslconf.h>
18
19#include <stdio.h>
20#include <string.h>
21
22#if !defined(OPENSSL_NO_RC4) && !defined(OPENSSL_NO_MD5)
23
24# include <openssl/crypto.h>
25# include <openssl/evp.h>
26# include <openssl/objects.h>
27# include <openssl/rc4.h>
28# include <openssl/md5.h>
29# include "crypto/evp.h"
30
31typedef struct {
32    RC4_KEY ks;
33    MD5_CTX head, tail, md;
34    size_t payload_length;
35} EVP_RC4_HMAC_MD5;
36
37# define NO_PAYLOAD_LENGTH       ((size_t)-1)
38
39void rc4_md5_enc(RC4_KEY *key, const void *in0, void *out,
40                 MD5_CTX *ctx, const void *inp, size_t blocks);
41
42# define data(ctx) ((EVP_RC4_HMAC_MD5 *)EVP_CIPHER_CTX_get_cipher_data(ctx))
43
44static int rc4_hmac_md5_init_key(EVP_CIPHER_CTX *ctx,
45                                 const unsigned char *inkey,
46                                 const unsigned char *iv, int enc)
47{
48    EVP_RC4_HMAC_MD5 *key = data(ctx);
49    const int keylen = EVP_CIPHER_CTX_get_key_length(ctx);
50
51    if (keylen <= 0)
52        return 0;
53
54    RC4_set_key(&key->ks, keylen, inkey);
55
56    MD5_Init(&key->head);       /* handy when benchmarking */
57    key->tail = key->head;
58    key->md = key->head;
59
60    key->payload_length = NO_PAYLOAD_LENGTH;
61
62    return 1;
63}
64
65# if     defined(RC4_ASM) && defined(MD5_ASM) &&     (     \
66        defined(__x86_64)       || defined(__x86_64__)  || \
67        defined(_M_AMD64)       || defined(_M_X64)      )
68#  define STITCHED_CALL
69# endif
70
71# if !defined(STITCHED_CALL)
72#  define rc4_off 0
73#  define md5_off 0
74# endif
75
76static int rc4_hmac_md5_cipher(EVP_CIPHER_CTX *ctx, unsigned char *out,
77                               const unsigned char *in, size_t len)
78{
79    EVP_RC4_HMAC_MD5 *key = data(ctx);
80# if defined(STITCHED_CALL)
81    size_t rc4_off = 32 - 1 - (key->ks.x & (32 - 1)), /* 32 is $MOD from
82                                                       * rc4_md5-x86_64.pl */
83        md5_off = MD5_CBLOCK - key->md.num, blocks;
84    unsigned int l;
85# endif
86    size_t plen = key->payload_length;
87
88    if (plen != NO_PAYLOAD_LENGTH && len != (plen + MD5_DIGEST_LENGTH))
89        return 0;
90
91    if (EVP_CIPHER_CTX_is_encrypting(ctx)) {
92        if (plen == NO_PAYLOAD_LENGTH)
93            plen = len;
94# if defined(STITCHED_CALL)
95        /* cipher has to "fall behind" */
96        if (rc4_off > md5_off)
97            md5_off += MD5_CBLOCK;
98
99        if (plen > md5_off && (blocks = (plen - md5_off) / MD5_CBLOCK) &&
100            (OPENSSL_ia32cap_P[0] & (1 << 20)) == 0) {
101            MD5_Update(&key->md, in, md5_off);
102            RC4(&key->ks, rc4_off, in, out);
103
104            rc4_md5_enc(&key->ks, in + rc4_off, out + rc4_off,
105                        &key->md, in + md5_off, blocks);
106            blocks *= MD5_CBLOCK;
107            rc4_off += blocks;
108            md5_off += blocks;
109            key->md.Nh += blocks >> 29;
110            key->md.Nl += blocks <<= 3;
111            if (key->md.Nl < (unsigned int)blocks)
112                key->md.Nh++;
113        } else {
114            rc4_off = 0;
115            md5_off = 0;
116        }
117# endif
118        MD5_Update(&key->md, in + md5_off, plen - md5_off);
119
120        if (plen != len) {      /* "TLS" mode of operation */
121            if (in != out)
122                memcpy(out + rc4_off, in + rc4_off, plen - rc4_off);
123
124            /* calculate HMAC and append it to payload */
125            MD5_Final(out + plen, &key->md);
126            key->md = key->tail;
127            MD5_Update(&key->md, out + plen, MD5_DIGEST_LENGTH);
128            MD5_Final(out + plen, &key->md);
129            /* encrypt HMAC at once */
130            RC4(&key->ks, len - rc4_off, out + rc4_off, out + rc4_off);
131        } else {
132            RC4(&key->ks, len - rc4_off, in + rc4_off, out + rc4_off);
133        }
134    } else {
135        unsigned char mac[MD5_DIGEST_LENGTH];
136# if defined(STITCHED_CALL)
137        /* digest has to "fall behind" */
138        if (md5_off > rc4_off)
139            rc4_off += 2 * MD5_CBLOCK;
140        else
141            rc4_off += MD5_CBLOCK;
142
143        if (len > rc4_off && (blocks = (len - rc4_off) / MD5_CBLOCK) &&
144            (OPENSSL_ia32cap_P[0] & (1 << 20)) == 0) {
145            RC4(&key->ks, rc4_off, in, out);
146            MD5_Update(&key->md, out, md5_off);
147
148            rc4_md5_enc(&key->ks, in + rc4_off, out + rc4_off,
149                        &key->md, out + md5_off, blocks);
150            blocks *= MD5_CBLOCK;
151            rc4_off += blocks;
152            md5_off += blocks;
153            l = (key->md.Nl + (blocks << 3)) & 0xffffffffU;
154            if (l < key->md.Nl)
155                key->md.Nh++;
156            key->md.Nl = l;
157            key->md.Nh += blocks >> 29;
158        } else {
159            md5_off = 0;
160            rc4_off = 0;
161        }
162# endif
163        /* decrypt HMAC at once */
164        RC4(&key->ks, len - rc4_off, in + rc4_off, out + rc4_off);
165        if (plen != NO_PAYLOAD_LENGTH) { /* "TLS" mode of operation */
166            MD5_Update(&key->md, out + md5_off, plen - md5_off);
167
168            /* calculate HMAC and verify it */
169            MD5_Final(mac, &key->md);
170            key->md = key->tail;
171            MD5_Update(&key->md, mac, MD5_DIGEST_LENGTH);
172            MD5_Final(mac, &key->md);
173
174            if (CRYPTO_memcmp(out + plen, mac, MD5_DIGEST_LENGTH))
175                return 0;
176        } else {
177            MD5_Update(&key->md, out + md5_off, len - md5_off);
178        }
179    }
180
181    key->payload_length = NO_PAYLOAD_LENGTH;
182
183    return 1;
184}
185
186static int rc4_hmac_md5_ctrl(EVP_CIPHER_CTX *ctx, int type, int arg,
187                             void *ptr)
188{
189    EVP_RC4_HMAC_MD5 *key = data(ctx);
190
191    switch (type) {
192    case EVP_CTRL_AEAD_SET_MAC_KEY:
193        {
194            unsigned int i;
195            unsigned char hmac_key[64];
196
197            memset(hmac_key, 0, sizeof(hmac_key));
198
199            if (arg > (int)sizeof(hmac_key)) {
200                MD5_Init(&key->head);
201                MD5_Update(&key->head, ptr, arg);
202                MD5_Final(hmac_key, &key->head);
203            } else {
204                memcpy(hmac_key, ptr, arg);
205            }
206
207            for (i = 0; i < sizeof(hmac_key); i++)
208                hmac_key[i] ^= 0x36; /* ipad */
209            MD5_Init(&key->head);
210            MD5_Update(&key->head, hmac_key, sizeof(hmac_key));
211
212            for (i = 0; i < sizeof(hmac_key); i++)
213                hmac_key[i] ^= 0x36 ^ 0x5c; /* opad */
214            MD5_Init(&key->tail);
215            MD5_Update(&key->tail, hmac_key, sizeof(hmac_key));
216
217            OPENSSL_cleanse(hmac_key, sizeof(hmac_key));
218
219            return 1;
220        }
221    case EVP_CTRL_AEAD_TLS1_AAD:
222        {
223            unsigned char *p = ptr;
224            unsigned int len;
225
226            if (arg != EVP_AEAD_TLS1_AAD_LEN)
227                return -1;
228
229            len = p[arg - 2] << 8 | p[arg - 1];
230
231            if (!EVP_CIPHER_CTX_is_encrypting(ctx)) {
232                if (len < MD5_DIGEST_LENGTH)
233                    return -1;
234                len -= MD5_DIGEST_LENGTH;
235                p[arg - 2] = len >> 8;
236                p[arg - 1] = len;
237            }
238            key->payload_length = len;
239            key->md = key->head;
240            MD5_Update(&key->md, p, arg);
241
242            return MD5_DIGEST_LENGTH;
243        }
244    default:
245        return -1;
246    }
247}
248
249static EVP_CIPHER r4_hmac_md5_cipher = {
250# ifdef NID_rc4_hmac_md5
251    NID_rc4_hmac_md5,
252# else
253    NID_undef,
254# endif
255    1, EVP_RC4_KEY_SIZE, 0,
256    EVP_CIPH_STREAM_CIPHER | EVP_CIPH_VARIABLE_LENGTH |
257        EVP_CIPH_FLAG_AEAD_CIPHER,
258    EVP_ORIG_GLOBAL,
259    rc4_hmac_md5_init_key,
260    rc4_hmac_md5_cipher,
261    NULL,
262    sizeof(EVP_RC4_HMAC_MD5),
263    NULL,
264    NULL,
265    rc4_hmac_md5_ctrl,
266    NULL
267};
268
269const EVP_CIPHER *EVP_rc4_hmac_md5(void)
270{
271    return &r4_hmac_md5_cipher;
272}
273#endif
274