xref: /openssl/crypto/evp/e_rc4_hmac_md5.c (revision ed576acd)
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 
31 typedef 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 
39 void 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 
rc4_hmac_md5_init_key(EVP_CIPHER_CTX * ctx,const unsigned char * inkey,const unsigned char * iv,int enc)44 static 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 
rc4_hmac_md5_cipher(EVP_CIPHER_CTX * ctx,unsigned char * out,const unsigned char * in,size_t len)76 static 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 
rc4_hmac_md5_ctrl(EVP_CIPHER_CTX * ctx,int type,int arg,void * ptr)186 static 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 
249 static 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 
EVP_rc4_hmac_md5(void)269 const EVP_CIPHER *EVP_rc4_hmac_md5(void)
270 {
271     return &r4_hmac_md5_cipher;
272 }
273 #endif
274