cast6_generic.c 9.1 KB

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  1. // SPDX-License-Identifier: GPL-2.0-or-later
  2. /* Kernel cryptographic api.
  3. * cast6.c - Cast6 cipher algorithm [rfc2612].
  4. *
  5. * CAST-256 (*cast6*) is a DES like Substitution-Permutation Network (SPN)
  6. * cryptosystem built upon the CAST-128 (*cast5*) [rfc2144] encryption
  7. * algorithm.
  8. *
  9. * Copyright (C) 2003 Kartikey Mahendra Bhatt <kartik_me@hotmail.com>.
  10. */
  11. #include <asm/byteorder.h>
  12. #include <linux/init.h>
  13. #include <linux/crypto.h>
  14. #include <linux/module.h>
  15. #include <linux/errno.h>
  16. #include <linux/string.h>
  17. #include <linux/types.h>
  18. #include <crypto/cast6.h>
  19. #define s1 cast_s1
  20. #define s2 cast_s2
  21. #define s3 cast_s3
  22. #define s4 cast_s4
  23. #define F1(D, r, m) ((I = ((m) + (D))), (I = rol32(I, (r))), \
  24. (((s1[I >> 24] ^ s2[(I>>16)&0xff]) - s3[(I>>8)&0xff]) + s4[I&0xff]))
  25. #define F2(D, r, m) ((I = ((m) ^ (D))), (I = rol32(I, (r))), \
  26. (((s1[I >> 24] - s2[(I>>16)&0xff]) + s3[(I>>8)&0xff]) ^ s4[I&0xff]))
  27. #define F3(D, r, m) ((I = ((m) - (D))), (I = rol32(I, (r))), \
  28. (((s1[I >> 24] + s2[(I>>16)&0xff]) ^ s3[(I>>8)&0xff]) - s4[I&0xff]))
  29. static const u32 Tm[24][8] = {
  30. { 0x5a827999, 0xc95c653a, 0x383650db, 0xa7103c7c, 0x15ea281d,
  31. 0x84c413be, 0xf39dff5f, 0x6277eb00 } ,
  32. { 0xd151d6a1, 0x402bc242, 0xaf05ade3, 0x1ddf9984, 0x8cb98525,
  33. 0xfb9370c6, 0x6a6d5c67, 0xd9474808 } ,
  34. { 0x482133a9, 0xb6fb1f4a, 0x25d50aeb, 0x94aef68c, 0x0388e22d,
  35. 0x7262cdce, 0xe13cb96f, 0x5016a510 } ,
  36. { 0xbef090b1, 0x2dca7c52, 0x9ca467f3, 0x0b7e5394, 0x7a583f35,
  37. 0xe9322ad6, 0x580c1677, 0xc6e60218 } ,
  38. { 0x35bfedb9, 0xa499d95a, 0x1373c4fb, 0x824db09c, 0xf1279c3d,
  39. 0x600187de, 0xcedb737f, 0x3db55f20 } ,
  40. { 0xac8f4ac1, 0x1b693662, 0x8a432203, 0xf91d0da4, 0x67f6f945,
  41. 0xd6d0e4e6, 0x45aad087, 0xb484bc28 } ,
  42. { 0x235ea7c9, 0x9238936a, 0x01127f0b, 0x6fec6aac, 0xdec6564d,
  43. 0x4da041ee, 0xbc7a2d8f, 0x2b541930 } ,
  44. { 0x9a2e04d1, 0x0907f072, 0x77e1dc13, 0xe6bbc7b4, 0x5595b355,
  45. 0xc46f9ef6, 0x33498a97, 0xa2237638 } ,
  46. { 0x10fd61d9, 0x7fd74d7a, 0xeeb1391b, 0x5d8b24bc, 0xcc65105d,
  47. 0x3b3efbfe, 0xaa18e79f, 0x18f2d340 } ,
  48. { 0x87ccbee1, 0xf6a6aa82, 0x65809623, 0xd45a81c4, 0x43346d65,
  49. 0xb20e5906, 0x20e844a7, 0x8fc23048 } ,
  50. { 0xfe9c1be9, 0x6d76078a, 0xdc4ff32b, 0x4b29decc, 0xba03ca6d,
  51. 0x28ddb60e, 0x97b7a1af, 0x06918d50 } ,
  52. { 0x756b78f1, 0xe4456492, 0x531f5033, 0xc1f93bd4, 0x30d32775,
  53. 0x9fad1316, 0x0e86feb7, 0x7d60ea58 } ,
  54. { 0xec3ad5f9, 0x5b14c19a, 0xc9eead3b, 0x38c898dc, 0xa7a2847d,
  55. 0x167c701e, 0x85565bbf, 0xf4304760 } ,
  56. { 0x630a3301, 0xd1e41ea2, 0x40be0a43, 0xaf97f5e4, 0x1e71e185,
  57. 0x8d4bcd26, 0xfc25b8c7, 0x6affa468 } ,
  58. { 0xd9d99009, 0x48b37baa, 0xb78d674b, 0x266752ec, 0x95413e8d,
  59. 0x041b2a2e, 0x72f515cf, 0xe1cf0170 } ,
  60. { 0x50a8ed11, 0xbf82d8b2, 0x2e5cc453, 0x9d36aff4, 0x0c109b95,
  61. 0x7aea8736, 0xe9c472d7, 0x589e5e78 } ,
  62. { 0xc7784a19, 0x365235ba, 0xa52c215b, 0x14060cfc, 0x82dff89d,
  63. 0xf1b9e43e, 0x6093cfdf, 0xcf6dbb80 } ,
  64. { 0x3e47a721, 0xad2192c2, 0x1bfb7e63, 0x8ad56a04, 0xf9af55a5,
  65. 0x68894146, 0xd7632ce7, 0x463d1888 } ,
  66. { 0xb5170429, 0x23f0efca, 0x92cadb6b, 0x01a4c70c, 0x707eb2ad,
  67. 0xdf589e4e, 0x4e3289ef, 0xbd0c7590 } ,
  68. { 0x2be66131, 0x9ac04cd2, 0x099a3873, 0x78742414, 0xe74e0fb5,
  69. 0x5627fb56, 0xc501e6f7, 0x33dbd298 } ,
  70. { 0xa2b5be39, 0x118fa9da, 0x8069957b, 0xef43811c, 0x5e1d6cbd,
  71. 0xccf7585e, 0x3bd143ff, 0xaaab2fa0 } ,
  72. { 0x19851b41, 0x885f06e2, 0xf738f283, 0x6612de24, 0xd4ecc9c5,
  73. 0x43c6b566, 0xb2a0a107, 0x217a8ca8 } ,
  74. { 0x90547849, 0xff2e63ea, 0x6e084f8b, 0xdce23b2c, 0x4bbc26cd,
  75. 0xba96126e, 0x296ffe0f, 0x9849e9b0 } ,
  76. { 0x0723d551, 0x75fdc0f2, 0xe4d7ac93, 0x53b19834, 0xc28b83d5,
  77. 0x31656f76, 0xa03f5b17, 0x0f1946b8 }
  78. };
  79. static const u8 Tr[4][8] = {
  80. { 0x13, 0x04, 0x15, 0x06, 0x17, 0x08, 0x19, 0x0a } ,
  81. { 0x1b, 0x0c, 0x1d, 0x0e, 0x1f, 0x10, 0x01, 0x12 } ,
  82. { 0x03, 0x14, 0x05, 0x16, 0x07, 0x18, 0x09, 0x1a } ,
  83. { 0x0b, 0x1c, 0x0d, 0x1e, 0x0f, 0x00, 0x11, 0x02 }
  84. };
  85. /* forward octave */
  86. static inline void W(u32 *key, unsigned int i)
  87. {
  88. u32 I;
  89. key[6] ^= F1(key[7], Tr[i % 4][0], Tm[i][0]);
  90. key[5] ^= F2(key[6], Tr[i % 4][1], Tm[i][1]);
  91. key[4] ^= F3(key[5], Tr[i % 4][2], Tm[i][2]);
  92. key[3] ^= F1(key[4], Tr[i % 4][3], Tm[i][3]);
  93. key[2] ^= F2(key[3], Tr[i % 4][4], Tm[i][4]);
  94. key[1] ^= F3(key[2], Tr[i % 4][5], Tm[i][5]);
  95. key[0] ^= F1(key[1], Tr[i % 4][6], Tm[i][6]);
  96. key[7] ^= F2(key[0], Tr[i % 4][7], Tm[i][7]);
  97. }
  98. int __cast6_setkey(struct cast6_ctx *c, const u8 *in_key, unsigned int key_len)
  99. {
  100. int i;
  101. u32 key[8];
  102. __be32 p_key[8]; /* padded key */
  103. if (key_len % 4 != 0)
  104. return -EINVAL;
  105. memset(p_key, 0, 32);
  106. memcpy(p_key, in_key, key_len);
  107. key[0] = be32_to_cpu(p_key[0]); /* A */
  108. key[1] = be32_to_cpu(p_key[1]); /* B */
  109. key[2] = be32_to_cpu(p_key[2]); /* C */
  110. key[3] = be32_to_cpu(p_key[3]); /* D */
  111. key[4] = be32_to_cpu(p_key[4]); /* E */
  112. key[5] = be32_to_cpu(p_key[5]); /* F */
  113. key[6] = be32_to_cpu(p_key[6]); /* G */
  114. key[7] = be32_to_cpu(p_key[7]); /* H */
  115. for (i = 0; i < 12; i++) {
  116. W(key, 2 * i);
  117. W(key, 2 * i + 1);
  118. c->Kr[i][0] = key[0] & 0x1f;
  119. c->Kr[i][1] = key[2] & 0x1f;
  120. c->Kr[i][2] = key[4] & 0x1f;
  121. c->Kr[i][3] = key[6] & 0x1f;
  122. c->Km[i][0] = key[7];
  123. c->Km[i][1] = key[5];
  124. c->Km[i][2] = key[3];
  125. c->Km[i][3] = key[1];
  126. }
  127. return 0;
  128. }
  129. EXPORT_SYMBOL_GPL(__cast6_setkey);
  130. int cast6_setkey(struct crypto_tfm *tfm, const u8 *key, unsigned int keylen)
  131. {
  132. return __cast6_setkey(crypto_tfm_ctx(tfm), key, keylen);
  133. }
  134. EXPORT_SYMBOL_GPL(cast6_setkey);
  135. /*forward quad round*/
  136. static inline void Q(u32 *block, const u8 *Kr, const u32 *Km)
  137. {
  138. u32 I;
  139. block[2] ^= F1(block[3], Kr[0], Km[0]);
  140. block[1] ^= F2(block[2], Kr[1], Km[1]);
  141. block[0] ^= F3(block[1], Kr[2], Km[2]);
  142. block[3] ^= F1(block[0], Kr[3], Km[3]);
  143. }
  144. /*reverse quad round*/
  145. static inline void QBAR(u32 *block, const u8 *Kr, const u32 *Km)
  146. {
  147. u32 I;
  148. block[3] ^= F1(block[0], Kr[3], Km[3]);
  149. block[0] ^= F3(block[1], Kr[2], Km[2]);
  150. block[1] ^= F2(block[2], Kr[1], Km[1]);
  151. block[2] ^= F1(block[3], Kr[0], Km[0]);
  152. }
  153. void __cast6_encrypt(const void *ctx, u8 *outbuf, const u8 *inbuf)
  154. {
  155. const struct cast6_ctx *c = ctx;
  156. const __be32 *src = (const __be32 *)inbuf;
  157. __be32 *dst = (__be32 *)outbuf;
  158. u32 block[4];
  159. const u32 *Km;
  160. const u8 *Kr;
  161. block[0] = be32_to_cpu(src[0]);
  162. block[1] = be32_to_cpu(src[1]);
  163. block[2] = be32_to_cpu(src[2]);
  164. block[3] = be32_to_cpu(src[3]);
  165. Km = c->Km[0]; Kr = c->Kr[0]; Q(block, Kr, Km);
  166. Km = c->Km[1]; Kr = c->Kr[1]; Q(block, Kr, Km);
  167. Km = c->Km[2]; Kr = c->Kr[2]; Q(block, Kr, Km);
  168. Km = c->Km[3]; Kr = c->Kr[3]; Q(block, Kr, Km);
  169. Km = c->Km[4]; Kr = c->Kr[4]; Q(block, Kr, Km);
  170. Km = c->Km[5]; Kr = c->Kr[5]; Q(block, Kr, Km);
  171. Km = c->Km[6]; Kr = c->Kr[6]; QBAR(block, Kr, Km);
  172. Km = c->Km[7]; Kr = c->Kr[7]; QBAR(block, Kr, Km);
  173. Km = c->Km[8]; Kr = c->Kr[8]; QBAR(block, Kr, Km);
  174. Km = c->Km[9]; Kr = c->Kr[9]; QBAR(block, Kr, Km);
  175. Km = c->Km[10]; Kr = c->Kr[10]; QBAR(block, Kr, Km);
  176. Km = c->Km[11]; Kr = c->Kr[11]; QBAR(block, Kr, Km);
  177. dst[0] = cpu_to_be32(block[0]);
  178. dst[1] = cpu_to_be32(block[1]);
  179. dst[2] = cpu_to_be32(block[2]);
  180. dst[3] = cpu_to_be32(block[3]);
  181. }
  182. EXPORT_SYMBOL_GPL(__cast6_encrypt);
  183. static void cast6_encrypt(struct crypto_tfm *tfm, u8 *outbuf, const u8 *inbuf)
  184. {
  185. __cast6_encrypt(crypto_tfm_ctx(tfm), outbuf, inbuf);
  186. }
  187. void __cast6_decrypt(const void *ctx, u8 *outbuf, const u8 *inbuf)
  188. {
  189. const struct cast6_ctx *c = ctx;
  190. const __be32 *src = (const __be32 *)inbuf;
  191. __be32 *dst = (__be32 *)outbuf;
  192. u32 block[4];
  193. const u32 *Km;
  194. const u8 *Kr;
  195. block[0] = be32_to_cpu(src[0]);
  196. block[1] = be32_to_cpu(src[1]);
  197. block[2] = be32_to_cpu(src[2]);
  198. block[3] = be32_to_cpu(src[3]);
  199. Km = c->Km[11]; Kr = c->Kr[11]; Q(block, Kr, Km);
  200. Km = c->Km[10]; Kr = c->Kr[10]; Q(block, Kr, Km);
  201. Km = c->Km[9]; Kr = c->Kr[9]; Q(block, Kr, Km);
  202. Km = c->Km[8]; Kr = c->Kr[8]; Q(block, Kr, Km);
  203. Km = c->Km[7]; Kr = c->Kr[7]; Q(block, Kr, Km);
  204. Km = c->Km[6]; Kr = c->Kr[6]; Q(block, Kr, Km);
  205. Km = c->Km[5]; Kr = c->Kr[5]; QBAR(block, Kr, Km);
  206. Km = c->Km[4]; Kr = c->Kr[4]; QBAR(block, Kr, Km);
  207. Km = c->Km[3]; Kr = c->Kr[3]; QBAR(block, Kr, Km);
  208. Km = c->Km[2]; Kr = c->Kr[2]; QBAR(block, Kr, Km);
  209. Km = c->Km[1]; Kr = c->Kr[1]; QBAR(block, Kr, Km);
  210. Km = c->Km[0]; Kr = c->Kr[0]; QBAR(block, Kr, Km);
  211. dst[0] = cpu_to_be32(block[0]);
  212. dst[1] = cpu_to_be32(block[1]);
  213. dst[2] = cpu_to_be32(block[2]);
  214. dst[3] = cpu_to_be32(block[3]);
  215. }
  216. EXPORT_SYMBOL_GPL(__cast6_decrypt);
  217. static void cast6_decrypt(struct crypto_tfm *tfm, u8 *outbuf, const u8 *inbuf)
  218. {
  219. __cast6_decrypt(crypto_tfm_ctx(tfm), outbuf, inbuf);
  220. }
  221. static struct crypto_alg alg = {
  222. .cra_name = "cast6",
  223. .cra_driver_name = "cast6-generic",
  224. .cra_priority = 100,
  225. .cra_flags = CRYPTO_ALG_TYPE_CIPHER,
  226. .cra_blocksize = CAST6_BLOCK_SIZE,
  227. .cra_ctxsize = sizeof(struct cast6_ctx),
  228. .cra_alignmask = 3,
  229. .cra_module = THIS_MODULE,
  230. .cra_u = {
  231. .cipher = {
  232. .cia_min_keysize = CAST6_MIN_KEY_SIZE,
  233. .cia_max_keysize = CAST6_MAX_KEY_SIZE,
  234. .cia_setkey = cast6_setkey,
  235. .cia_encrypt = cast6_encrypt,
  236. .cia_decrypt = cast6_decrypt}
  237. }
  238. };
  239. static int __init cast6_mod_init(void)
  240. {
  241. return crypto_register_alg(&alg);
  242. }
  243. static void __exit cast6_mod_fini(void)
  244. {
  245. crypto_unregister_alg(&alg);
  246. }
  247. subsys_initcall(cast6_mod_init);
  248. module_exit(cast6_mod_fini);
  249. MODULE_LICENSE("GPL");
  250. MODULE_DESCRIPTION("Cast6 Cipher Algorithm");
  251. MODULE_ALIAS_CRYPTO("cast6");
  252. MODULE_ALIAS_CRYPTO("cast6-generic");