1 /*
2 * Cryptographic API.
3 *
4 * CRC32C chksum
5 *
6 *@Article{castagnoli-crc,
7 * author = { Guy Castagnoli and Stefan Braeuer and Martin Herrman},
8 * title = {{Optimization of Cyclic Redundancy-Check Codes with 24
9 * and 32 Parity Bits}},
10 * journal = IEEE Transactions on Communication,
11 * year = {1993},
12 * volume = {41},
13 * number = {6},
14 * pages = {},
15 * month = {June},
16 *}
17 * Used by the iSCSI driver, possibly others, and derived from the
18 * the iscsi-crc.c module of the linux-iscsi driver at
19 * http://linux-iscsi.sourceforge.net.
20 *
21 * Following the example of lib/crc32, this function is intended to be
22 * flexible and useful for all users. Modules that currently have their
23 * own crc32c, but hopefully may be able to use this one are:
24 * net/sctp (please add all your doco to here if you change to
25 * use this one!)
26 * <endoflist>
27 *
28 * Copyright (c) 2004 Cisco Systems, Inc.
29 * Copyright (c) 2008 Herbert Xu <herbert@gondor.apana.org.au>
30 *
31 * This program is free software; you can redistribute it and/or modify it
32 * under the terms of the GNU General Public License as published by the Free
33 * Software Foundation; either version 2 of the License, or (at your option)
34 * any later version.
35 *
36 */
37
38 #include <crypto/internal/hash.h>
39 #include <linux/init.h>
40 #include <linux/module.h>
41 #include <linux/string.h>
42 #include <linux/kernel.h>
43
44 #define CHKSUM_BLOCK_SIZE 1
45 #define CHKSUM_DIGEST_SIZE 4
46
47 struct chksum_ctx {
48 u32 key;
49 };
50
51 struct chksum_desc_ctx {
52 u32 crc;
53 };
54
55 /*
56 * This is the CRC-32C table
57 * Generated with:
58 * width = 32 bits
59 * poly = 0x1EDC6F41
60 * reflect input bytes = true
61 * reflect output bytes = true
62 */
63
64 static const u32 crc32c_table[256] = {
65 0x00000000L, 0xF26B8303L, 0xE13B70F7L, 0x1350F3F4L,
66 0xC79A971FL, 0x35F1141CL, 0x26A1E7E8L, 0xD4CA64EBL,
67 0x8AD958CFL, 0x78B2DBCCL, 0x6BE22838L, 0x9989AB3BL,
68 0x4D43CFD0L, 0xBF284CD3L, 0xAC78BF27L, 0x5E133C24L,
69 0x105EC76FL, 0xE235446CL, 0xF165B798L, 0x030E349BL,
70 0xD7C45070L, 0x25AFD373L, 0x36FF2087L, 0xC494A384L,
71 0x9A879FA0L, 0x68EC1CA3L, 0x7BBCEF57L, 0x89D76C54L,
72 0x5D1D08BFL, 0xAF768BBCL, 0xBC267848L, 0x4E4DFB4BL,
73 0x20BD8EDEL, 0xD2D60DDDL, 0xC186FE29L, 0x33ED7D2AL,
74 0xE72719C1L, 0x154C9AC2L, 0x061C6936L, 0xF477EA35L,
75 0xAA64D611L, 0x580F5512L, 0x4B5FA6E6L, 0xB93425E5L,
76 0x6DFE410EL, 0x9F95C20DL, 0x8CC531F9L, 0x7EAEB2FAL,
77 0x30E349B1L, 0xC288CAB2L, 0xD1D83946L, 0x23B3BA45L,
78 0xF779DEAEL, 0x05125DADL, 0x1642AE59L, 0xE4292D5AL,
79 0xBA3A117EL, 0x4851927DL, 0x5B016189L, 0xA96AE28AL,
80 0x7DA08661L, 0x8FCB0562L, 0x9C9BF696L, 0x6EF07595L,
81 0x417B1DBCL, 0xB3109EBFL, 0xA0406D4BL, 0x522BEE48L,
82 0x86E18AA3L, 0x748A09A0L, 0x67DAFA54L, 0x95B17957L,
83 0xCBA24573L, 0x39C9C670L, 0x2A993584L, 0xD8F2B687L,
84 0x0C38D26CL, 0xFE53516FL, 0xED03A29BL, 0x1F682198L,
85 0x5125DAD3L, 0xA34E59D0L, 0xB01EAA24L, 0x42752927L,
86 0x96BF4DCCL, 0x64D4CECFL, 0x77843D3BL, 0x85EFBE38L,
87 0xDBFC821CL, 0x2997011FL, 0x3AC7F2EBL, 0xC8AC71E8L,
88 0x1C661503L, 0xEE0D9600L, 0xFD5D65F4L, 0x0F36E6F7L,
89 0x61C69362L, 0x93AD1061L, 0x80FDE395L, 0x72966096L,
90 0xA65C047DL, 0x5437877EL, 0x4767748AL, 0xB50CF789L,
91 0xEB1FCBADL, 0x197448AEL, 0x0A24BB5AL, 0xF84F3859L,
92 0x2C855CB2L, 0xDEEEDFB1L, 0xCDBE2C45L, 0x3FD5AF46L,
93 0x7198540DL, 0x83F3D70EL, 0x90A324FAL, 0x62C8A7F9L,
94 0xB602C312L, 0x44694011L, 0x5739B3E5L, 0xA55230E6L,
95 0xFB410CC2L, 0x092A8FC1L, 0x1A7A7C35L, 0xE811FF36L,
96 0x3CDB9BDDL, 0xCEB018DEL, 0xDDE0EB2AL, 0x2F8B6829L,
97 0x82F63B78L, 0x709DB87BL, 0x63CD4B8FL, 0x91A6C88CL,
98 0x456CAC67L, 0xB7072F64L, 0xA457DC90L, 0x563C5F93L,
99 0x082F63B7L, 0xFA44E0B4L, 0xE9141340L, 0x1B7F9043L,
100 0xCFB5F4A8L, 0x3DDE77ABL, 0x2E8E845FL, 0xDCE5075CL,
101 0x92A8FC17L, 0x60C37F14L, 0x73938CE0L, 0x81F80FE3L,
102 0x55326B08L, 0xA759E80BL, 0xB4091BFFL, 0x466298FCL,
103 0x1871A4D8L, 0xEA1A27DBL, 0xF94AD42FL, 0x0B21572CL,
104 0xDFEB33C7L, 0x2D80B0C4L, 0x3ED04330L, 0xCCBBC033L,
105 0xA24BB5A6L, 0x502036A5L, 0x4370C551L, 0xB11B4652L,
106 0x65D122B9L, 0x97BAA1BAL, 0x84EA524EL, 0x7681D14DL,
107 0x2892ED69L, 0xDAF96E6AL, 0xC9A99D9EL, 0x3BC21E9DL,
108 0xEF087A76L, 0x1D63F975L, 0x0E330A81L, 0xFC588982L,
109 0xB21572C9L, 0x407EF1CAL, 0x532E023EL, 0xA145813DL,
110 0x758FE5D6L, 0x87E466D5L, 0x94B49521L, 0x66DF1622L,
111 0x38CC2A06L, 0xCAA7A905L, 0xD9F75AF1L, 0x2B9CD9F2L,
112 0xFF56BD19L, 0x0D3D3E1AL, 0x1E6DCDEEL, 0xEC064EEDL,
113 0xC38D26C4L, 0x31E6A5C7L, 0x22B65633L, 0xD0DDD530L,
114 0x0417B1DBL, 0xF67C32D8L, 0xE52CC12CL, 0x1747422FL,
115 0x49547E0BL, 0xBB3FFD08L, 0xA86F0EFCL, 0x5A048DFFL,
116 0x8ECEE914L, 0x7CA56A17L, 0x6FF599E3L, 0x9D9E1AE0L,
117 0xD3D3E1ABL, 0x21B862A8L, 0x32E8915CL, 0xC083125FL,
118 0x144976B4L, 0xE622F5B7L, 0xF5720643L, 0x07198540L,
119 0x590AB964L, 0xAB613A67L, 0xB831C993L, 0x4A5A4A90L,
120 0x9E902E7BL, 0x6CFBAD78L, 0x7FAB5E8CL, 0x8DC0DD8FL,
121 0xE330A81AL, 0x115B2B19L, 0x020BD8EDL, 0xF0605BEEL,
122 0x24AA3F05L, 0xD6C1BC06L, 0xC5914FF2L, 0x37FACCF1L,
123 0x69E9F0D5L, 0x9B8273D6L, 0x88D28022L, 0x7AB90321L,
124 0xAE7367CAL, 0x5C18E4C9L, 0x4F48173DL, 0xBD23943EL,
125 0xF36E6F75L, 0x0105EC76L, 0x12551F82L, 0xE03E9C81L,
126 0x34F4F86AL, 0xC69F7B69L, 0xD5CF889DL, 0x27A40B9EL,
127 0x79B737BAL, 0x8BDCB4B9L, 0x988C474DL, 0x6AE7C44EL,
128 0xBE2DA0A5L, 0x4C4623A6L, 0x5F16D052L, 0xAD7D5351L
129 };
130
131 /*
132 * Steps through buffer one byte at at time, calculates reflected
133 * crc using table.
134 */
135
crc32c(u32 crc,const u8 * data,unsigned int length)136 static u32 crc32c(u32 crc, const u8 *data, unsigned int length)
137 {
138 while (length--)
139 crc = crc32c_table[(crc ^ *data++) & 0xFFL] ^ (crc >> 8);
140
141 return crc;
142 }
143
144 /*
145 * Steps through buffer one byte at at time, calculates reflected
146 * crc using table.
147 */
148
chksum_init(struct shash_desc * desc)149 static int chksum_init(struct shash_desc *desc)
150 {
151 struct chksum_ctx *mctx = crypto_shash_ctx(desc->tfm);
152 struct chksum_desc_ctx *ctx = shash_desc_ctx(desc);
153
154 ctx->crc = mctx->key;
155
156 return 0;
157 }
158
159 /*
160 * Setting the seed allows arbitrary accumulators and flexible XOR policy
161 * If your algorithm starts with ~0, then XOR with ~0 before you set
162 * the seed.
163 */
chksum_setkey(struct crypto_shash * tfm,const u8 * key,unsigned int keylen)164 static int chksum_setkey(struct crypto_shash *tfm, const u8 *key,
165 unsigned int keylen)
166 {
167 struct chksum_ctx *mctx = crypto_shash_ctx(tfm);
168
169 if (keylen != sizeof(mctx->key)) {
170 crypto_shash_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
171 return -EINVAL;
172 }
173 mctx->key = le32_to_cpu(*(__le32 *)key);
174 return 0;
175 }
176
chksum_update(struct shash_desc * desc,const u8 * data,unsigned int length)177 static int chksum_update(struct shash_desc *desc, const u8 *data,
178 unsigned int length)
179 {
180 struct chksum_desc_ctx *ctx = shash_desc_ctx(desc);
181
182 ctx->crc = crc32c(ctx->crc, data, length);
183 return 0;
184 }
185
chksum_final(struct shash_desc * desc,u8 * out)186 static int chksum_final(struct shash_desc *desc, u8 *out)
187 {
188 struct chksum_desc_ctx *ctx = shash_desc_ctx(desc);
189
190 *(__le32 *)out = ~cpu_to_le32p(&ctx->crc);
191 return 0;
192 }
193
__chksum_finup(u32 * crcp,const u8 * data,unsigned int len,u8 * out)194 static int __chksum_finup(u32 *crcp, const u8 *data, unsigned int len, u8 *out)
195 {
196 *(__le32 *)out = ~cpu_to_le32(crc32c(*crcp, data, len));
197 return 0;
198 }
199
chksum_finup(struct shash_desc * desc,const u8 * data,unsigned int len,u8 * out)200 static int chksum_finup(struct shash_desc *desc, const u8 *data,
201 unsigned int len, u8 *out)
202 {
203 struct chksum_desc_ctx *ctx = shash_desc_ctx(desc);
204
205 return __chksum_finup(&ctx->crc, data, len, out);
206 }
207
chksum_digest(struct shash_desc * desc,const u8 * data,unsigned int length,u8 * out)208 static int chksum_digest(struct shash_desc *desc, const u8 *data,
209 unsigned int length, u8 *out)
210 {
211 struct chksum_ctx *mctx = crypto_shash_ctx(desc->tfm);
212
213 return __chksum_finup(&mctx->key, data, length, out);
214 }
215
crc32c_cra_init(struct crypto_tfm * tfm)216 static int crc32c_cra_init(struct crypto_tfm *tfm)
217 {
218 struct chksum_ctx *mctx = crypto_tfm_ctx(tfm);
219
220 mctx->key = ~0;
221 return 0;
222 }
223
224 static struct shash_alg alg = {
225 .digestsize = CHKSUM_DIGEST_SIZE,
226 .setkey = chksum_setkey,
227 .init = chksum_init,
228 .update = chksum_update,
229 .final = chksum_final,
230 .finup = chksum_finup,
231 .digest = chksum_digest,
232 .descsize = sizeof(struct chksum_desc_ctx),
233 .base = {
234 .cra_name = "crc32c",
235 .cra_driver_name = "crc32c-generic",
236 .cra_priority = 100,
237 .cra_blocksize = CHKSUM_BLOCK_SIZE,
238 .cra_alignmask = 3,
239 .cra_ctxsize = sizeof(struct chksum_ctx),
240 .cra_module = THIS_MODULE,
241 .cra_init = crc32c_cra_init,
242 }
243 };
244
crc32c_mod_init(void)245 static int __init crc32c_mod_init(void)
246 {
247 return crypto_register_shash(&alg);
248 }
249
crc32c_mod_fini(void)250 static void __exit crc32c_mod_fini(void)
251 {
252 crypto_unregister_shash(&alg);
253 }
254
255 module_init(crc32c_mod_init);
256 module_exit(crc32c_mod_fini);
257
258 MODULE_AUTHOR("Clay Haapala <chaapala@cisco.com>");
259 MODULE_DESCRIPTION("CRC32c (Castagnoli) calculations wrapper for lib/crc32c");
260 MODULE_LICENSE("GPL");
261