1 /* LibTomCrypt, modular cryptographic library -- Tom St Denis */
2 /* SPDX-License-Identifier: Unlicense */
3
4 /* Auto-detection of AES implementation by Steffen Jaeckel */
5 /**
6 @file aes_desc.c
7 Run-time detection of correct AES implementation
8 */
9
10 #include "tomcrypt_private.h"
11
12 #if defined(LTC_RIJNDAEL)
13
14 #ifndef ENCRYPT_ONLY
15
16 #define AES_SETUP aes_setup
17 #define AES_ENC aes_ecb_encrypt
18 #define AES_DEC aes_ecb_decrypt
19 #define AES_DONE aes_done
20 #define AES_TEST aes_test
21 #define AES_KS aes_keysize
22
23 const struct ltc_cipher_descriptor aes_desc =
24 {
25 "aes",
26 6,
27 16, 32, 16, 10,
28 AES_SETUP, AES_ENC, AES_DEC, AES_TEST, AES_DONE, AES_KS,
29 NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL
30 };
31
32 #else
33
34 #define AES_SETUP aes_enc_setup
35 #define AES_ENC aes_enc_ecb_encrypt
36 #define AES_DONE aes_enc_done
37 #define AES_TEST aes_enc_test
38 #define AES_KS aes_enc_keysize
39
40 const struct ltc_cipher_descriptor aes_enc_desc =
41 {
42 "aes",
43 6,
44 16, 32, 16, 10,
45 AES_SETUP, AES_ENC, NULL, NULL, AES_DONE, AES_KS,
46 NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL
47 };
48
49 #endif
50
51 /* Code partially borrowed from https://software.intel.com/content/www/us/en/develop/articles/intel-sha-extensions.html */
52 #if defined(LTC_HAS_AES_NI)
s_aesni_is_supported(void)53 static LTC_INLINE int s_aesni_is_supported(void)
54 {
55 static int initialized = 0, is_supported = 0;
56
57 if (initialized == 0) {
58 int a, b, c, d;
59
60 /* Look for CPUID.1.0.ECX[25]
61 * EAX = 1, ECX = 0
62 */
63 a = 1;
64 c = 0;
65
66 asm volatile ("cpuid"
67 :"=a"(a), "=b"(b), "=c"(c), "=d"(d)
68 :"a"(a), "c"(c)
69 );
70
71 is_supported = ((c >> 25) & 1);
72 initialized = 1;
73 }
74
75 return is_supported;
76 }
77
78 #ifndef ENCRYPT_ONLY
aesni_is_supported(void)79 int aesni_is_supported(void)
80 {
81 return s_aesni_is_supported();
82 }
83 #endif
84 #endif
85
86 /**
87 Initialize the AES (Rijndael) block cipher
88 @param key The symmetric key you wish to pass
89 @param keylen The key length in bytes
90 @param num_rounds The number of rounds desired (0 for default)
91 @param skey The key in as scheduled by this function.
92 @return CRYPT_OK if successful
93 */
AES_SETUP(const unsigned char * key,int keylen,int num_rounds,symmetric_key * skey)94 int AES_SETUP(const unsigned char *key, int keylen, int num_rounds, symmetric_key *skey)
95 {
96 #ifdef LTC_HAS_AES_NI
97 if (s_aesni_is_supported()) {
98 return aesni_setup(key, keylen, num_rounds, skey);
99 }
100 #endif
101 /* Last resort, software AES */
102 return rijndael_setup(key, keylen, num_rounds, skey);
103 }
104
105 /**
106 Encrypts a block of text with AES
107 @param pt The input plaintext (16 bytes)
108 @param ct The output ciphertext (16 bytes)
109 @param skey The key as scheduled
110 @return CRYPT_OK if successful
111 */
AES_ENC(const unsigned char * pt,unsigned char * ct,const symmetric_key * skey)112 int AES_ENC(const unsigned char *pt, unsigned char *ct, const symmetric_key *skey)
113 {
114 #ifdef LTC_HAS_AES_NI
115 if (s_aesni_is_supported()) {
116 return aesni_ecb_encrypt(pt, ct, skey);
117 }
118 #endif
119 return rijndael_ecb_encrypt(pt, ct, skey);
120 }
121
122
123 #ifndef ENCRYPT_ONLY
124 /**
125 Decrypts a block of text with AES
126 @param ct The input ciphertext (16 bytes)
127 @param pt The output plaintext (16 bytes)
128 @param skey The key as scheduled
129 @return CRYPT_OK if successful
130 */
AES_DEC(const unsigned char * ct,unsigned char * pt,const symmetric_key * skey)131 int AES_DEC(const unsigned char *ct, unsigned char *pt, const symmetric_key *skey)
132 {
133 #ifdef LTC_HAS_AES_NI
134 if (s_aesni_is_supported()) {
135 return aesni_ecb_decrypt(ct, pt, skey);
136 }
137 #endif
138 return rijndael_ecb_decrypt(ct, pt, skey);
139 }
140 #endif /* ENCRYPT_ONLY */
141
142 /**
143 Performs a self-test of the AES block cipher
144 @return CRYPT_OK if functional, CRYPT_NOP if self-test has been disabled
145 */
AES_TEST(void)146 int AES_TEST(void)
147 {
148 #ifndef LTC_TEST
149 return CRYPT_NOP;
150 #else
151 int err;
152 static const struct {
153 int keylen;
154 unsigned char key[32], pt[16], ct[16];
155 } tests[] = {
156 { 16,
157 { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
158 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f },
159 { 0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77,
160 0x88, 0x99, 0xaa, 0xbb, 0xcc, 0xdd, 0xee, 0xff },
161 { 0x69, 0xc4, 0xe0, 0xd8, 0x6a, 0x7b, 0x04, 0x30,
162 0xd8, 0xcd, 0xb7, 0x80, 0x70, 0xb4, 0xc5, 0x5a }
163 }, {
164 24,
165 { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
166 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
167 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17 },
168 { 0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77,
169 0x88, 0x99, 0xaa, 0xbb, 0xcc, 0xdd, 0xee, 0xff },
170 { 0xdd, 0xa9, 0x7c, 0xa4, 0x86, 0x4c, 0xdf, 0xe0,
171 0x6e, 0xaf, 0x70, 0xa0, 0xec, 0x0d, 0x71, 0x91 }
172 }, {
173 32,
174 { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
175 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
176 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
177 0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f },
178 { 0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77,
179 0x88, 0x99, 0xaa, 0xbb, 0xcc, 0xdd, 0xee, 0xff },
180 { 0x8e, 0xa2, 0xb7, 0xca, 0x51, 0x67, 0x45, 0xbf,
181 0xea, 0xfc, 0x49, 0x90, 0x4b, 0x49, 0x60, 0x89 }
182 }
183 };
184
185 symmetric_key key;
186 unsigned char tmp[2][16];
187 int i;
188 #ifndef ENCRYPT_ONLY
189 int y;
190 #endif
191
192 for (i = 0; i < (int)(sizeof(tests)/sizeof(tests[0])); i++) {
193 zeromem(&key, sizeof(key));
194 if ((err = AES_SETUP(tests[i].key, tests[i].keylen, 0, &key)) != CRYPT_OK) {
195 return err;
196 }
197
198 AES_ENC(tests[i].pt, tmp[0], &key);
199 if (compare_testvector(tmp[0], 16, tests[i].ct, 16, "AES Encrypt", i)) {
200 return CRYPT_FAIL_TESTVECTOR;
201 }
202 #ifndef ENCRYPT_ONLY
203 AES_DEC(tmp[0], tmp[1], &key);
204 if (compare_testvector(tmp[1], 16, tests[i].pt, 16, "AES Decrypt", i)) {
205 return CRYPT_FAIL_TESTVECTOR;
206 }
207
208 /* now see if we can encrypt all zero bytes 1000 times, decrypt and come back where we started */
209 for (y = 0; y < 16; y++) tmp[0][y] = 0;
210 for (y = 0; y < 1000; y++) AES_ENC(tmp[0], tmp[0], &key);
211 for (y = 0; y < 1000; y++) AES_DEC(tmp[0], tmp[0], &key);
212 for (y = 0; y < 16; y++) if (tmp[0][y] != 0) return CRYPT_FAIL_TESTVECTOR;
213 #endif
214 }
215 return CRYPT_OK;
216 #endif
217 }
218
219
220 /** Terminate the context
221 @param skey The scheduled key
222 */
AES_DONE(symmetric_key * skey)223 void AES_DONE(symmetric_key *skey)
224 {
225 LTC_UNUSED_PARAM(skey);
226 }
227
228
229 /**
230 Gets suitable key size
231 @param keysize [in/out] The length of the recommended key (in bytes). This function will store the suitable size back in this variable.
232 @return CRYPT_OK if the input key size is acceptable.
233 */
AES_KS(int * keysize)234 int AES_KS(int *keysize)
235 {
236 LTC_ARGCHK(keysize != NULL);
237
238 if (*keysize < 16) {
239 return CRYPT_INVALID_KEYSIZE;
240 }
241 if (*keysize < 24) {
242 *keysize = 16;
243 return CRYPT_OK;
244 }
245 if (*keysize < 32) {
246 *keysize = 24;
247 return CRYPT_OK;
248 }
249 *keysize = 32;
250 return CRYPT_OK;
251 }
252
253 #endif
254
255