Version:  2.0.40 2.2.26 2.4.37 3.13 3.14 3.15 3.16 3.17 3.18 3.19 4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 4.10

Linux/crypto/poly1305_generic.c

  1 /*
  2  * Poly1305 authenticator algorithm, RFC7539
  3  *
  4  * Copyright (C) 2015 Martin Willi
  5  *
  6  * Based on public domain code by Andrew Moon and Daniel J. Bernstein.
  7  *
  8  * This program is free software; you can redistribute it and/or modify
  9  * it under the terms of the GNU General Public License as published by
 10  * the Free Software Foundation; either version 2 of the License, or
 11  * (at your option) any later version.
 12  */
 13 
 14 #include <crypto/algapi.h>
 15 #include <crypto/internal/hash.h>
 16 #include <crypto/poly1305.h>
 17 #include <linux/crypto.h>
 18 #include <linux/kernel.h>
 19 #include <linux/module.h>
 20 #include <asm/unaligned.h>
 21 
 22 static inline u64 mlt(u64 a, u64 b)
 23 {
 24         return a * b;
 25 }
 26 
 27 static inline u32 sr(u64 v, u_char n)
 28 {
 29         return v >> n;
 30 }
 31 
 32 static inline u32 and(u32 v, u32 mask)
 33 {
 34         return v & mask;
 35 }
 36 
 37 int crypto_poly1305_init(struct shash_desc *desc)
 38 {
 39         struct poly1305_desc_ctx *dctx = shash_desc_ctx(desc);
 40 
 41         memset(dctx->h, 0, sizeof(dctx->h));
 42         dctx->buflen = 0;
 43         dctx->rset = false;
 44         dctx->sset = false;
 45 
 46         return 0;
 47 }
 48 EXPORT_SYMBOL_GPL(crypto_poly1305_init);
 49 
 50 int crypto_poly1305_setkey(struct crypto_shash *tfm,
 51                            const u8 *key, unsigned int keylen)
 52 {
 53         /* Poly1305 requires a unique key for each tag, which implies that
 54          * we can't set it on the tfm that gets accessed by multiple users
 55          * simultaneously. Instead we expect the key as the first 32 bytes in
 56          * the update() call. */
 57         return -ENOTSUPP;
 58 }
 59 EXPORT_SYMBOL_GPL(crypto_poly1305_setkey);
 60 
 61 static void poly1305_setrkey(struct poly1305_desc_ctx *dctx, const u8 *key)
 62 {
 63         /* r &= 0xffffffc0ffffffc0ffffffc0fffffff */
 64         dctx->r[0] = (get_unaligned_le32(key +  0) >> 0) & 0x3ffffff;
 65         dctx->r[1] = (get_unaligned_le32(key +  3) >> 2) & 0x3ffff03;
 66         dctx->r[2] = (get_unaligned_le32(key +  6) >> 4) & 0x3ffc0ff;
 67         dctx->r[3] = (get_unaligned_le32(key +  9) >> 6) & 0x3f03fff;
 68         dctx->r[4] = (get_unaligned_le32(key + 12) >> 8) & 0x00fffff;
 69 }
 70 
 71 static void poly1305_setskey(struct poly1305_desc_ctx *dctx, const u8 *key)
 72 {
 73         dctx->s[0] = get_unaligned_le32(key +  0);
 74         dctx->s[1] = get_unaligned_le32(key +  4);
 75         dctx->s[2] = get_unaligned_le32(key +  8);
 76         dctx->s[3] = get_unaligned_le32(key + 12);
 77 }
 78 
 79 unsigned int crypto_poly1305_setdesckey(struct poly1305_desc_ctx *dctx,
 80                                         const u8 *src, unsigned int srclen)
 81 {
 82         if (!dctx->sset) {
 83                 if (!dctx->rset && srclen >= POLY1305_BLOCK_SIZE) {
 84                         poly1305_setrkey(dctx, src);
 85                         src += POLY1305_BLOCK_SIZE;
 86                         srclen -= POLY1305_BLOCK_SIZE;
 87                         dctx->rset = true;
 88                 }
 89                 if (srclen >= POLY1305_BLOCK_SIZE) {
 90                         poly1305_setskey(dctx, src);
 91                         src += POLY1305_BLOCK_SIZE;
 92                         srclen -= POLY1305_BLOCK_SIZE;
 93                         dctx->sset = true;
 94                 }
 95         }
 96         return srclen;
 97 }
 98 EXPORT_SYMBOL_GPL(crypto_poly1305_setdesckey);
 99 
100 static unsigned int poly1305_blocks(struct poly1305_desc_ctx *dctx,
101                                     const u8 *src, unsigned int srclen,
102                                     u32 hibit)
103 {
104         u32 r0, r1, r2, r3, r4;
105         u32 s1, s2, s3, s4;
106         u32 h0, h1, h2, h3, h4;
107         u64 d0, d1, d2, d3, d4;
108         unsigned int datalen;
109 
110         if (unlikely(!dctx->sset)) {
111                 datalen = crypto_poly1305_setdesckey(dctx, src, srclen);
112                 src += srclen - datalen;
113                 srclen = datalen;
114         }
115 
116         r0 = dctx->r[0];
117         r1 = dctx->r[1];
118         r2 = dctx->r[2];
119         r3 = dctx->r[3];
120         r4 = dctx->r[4];
121 
122         s1 = r1 * 5;
123         s2 = r2 * 5;
124         s3 = r3 * 5;
125         s4 = r4 * 5;
126 
127         h0 = dctx->h[0];
128         h1 = dctx->h[1];
129         h2 = dctx->h[2];
130         h3 = dctx->h[3];
131         h4 = dctx->h[4];
132 
133         while (likely(srclen >= POLY1305_BLOCK_SIZE)) {
134 
135                 /* h += m[i] */
136                 h0 += (get_unaligned_le32(src +  0) >> 0) & 0x3ffffff;
137                 h1 += (get_unaligned_le32(src +  3) >> 2) & 0x3ffffff;
138                 h2 += (get_unaligned_le32(src +  6) >> 4) & 0x3ffffff;
139                 h3 += (get_unaligned_le32(src +  9) >> 6) & 0x3ffffff;
140                 h4 += (get_unaligned_le32(src + 12) >> 8) | hibit;
141 
142                 /* h *= r */
143                 d0 = mlt(h0, r0) + mlt(h1, s4) + mlt(h2, s3) +
144                      mlt(h3, s2) + mlt(h4, s1);
145                 d1 = mlt(h0, r1) + mlt(h1, r0) + mlt(h2, s4) +
146                      mlt(h3, s3) + mlt(h4, s2);
147                 d2 = mlt(h0, r2) + mlt(h1, r1) + mlt(h2, r0) +
148                      mlt(h3, s4) + mlt(h4, s3);
149                 d3 = mlt(h0, r3) + mlt(h1, r2) + mlt(h2, r1) +
150                      mlt(h3, r0) + mlt(h4, s4);
151                 d4 = mlt(h0, r4) + mlt(h1, r3) + mlt(h2, r2) +
152                      mlt(h3, r1) + mlt(h4, r0);
153 
154                 /* (partial) h %= p */
155                 d1 += sr(d0, 26);     h0 = and(d0, 0x3ffffff);
156                 d2 += sr(d1, 26);     h1 = and(d1, 0x3ffffff);
157                 d3 += sr(d2, 26);     h2 = and(d2, 0x3ffffff);
158                 d4 += sr(d3, 26);     h3 = and(d3, 0x3ffffff);
159                 h0 += sr(d4, 26) * 5; h4 = and(d4, 0x3ffffff);
160                 h1 += h0 >> 26;       h0 = h0 & 0x3ffffff;
161 
162                 src += POLY1305_BLOCK_SIZE;
163                 srclen -= POLY1305_BLOCK_SIZE;
164         }
165 
166         dctx->h[0] = h0;
167         dctx->h[1] = h1;
168         dctx->h[2] = h2;
169         dctx->h[3] = h3;
170         dctx->h[4] = h4;
171 
172         return srclen;
173 }
174 
175 int crypto_poly1305_update(struct shash_desc *desc,
176                            const u8 *src, unsigned int srclen)
177 {
178         struct poly1305_desc_ctx *dctx = shash_desc_ctx(desc);
179         unsigned int bytes;
180 
181         if (unlikely(dctx->buflen)) {
182                 bytes = min(srclen, POLY1305_BLOCK_SIZE - dctx->buflen);
183                 memcpy(dctx->buf + dctx->buflen, src, bytes);
184                 src += bytes;
185                 srclen -= bytes;
186                 dctx->buflen += bytes;
187 
188                 if (dctx->buflen == POLY1305_BLOCK_SIZE) {
189                         poly1305_blocks(dctx, dctx->buf,
190                                         POLY1305_BLOCK_SIZE, 1 << 24);
191                         dctx->buflen = 0;
192                 }
193         }
194 
195         if (likely(srclen >= POLY1305_BLOCK_SIZE)) {
196                 bytes = poly1305_blocks(dctx, src, srclen, 1 << 24);
197                 src += srclen - bytes;
198                 srclen = bytes;
199         }
200 
201         if (unlikely(srclen)) {
202                 dctx->buflen = srclen;
203                 memcpy(dctx->buf, src, srclen);
204         }
205 
206         return 0;
207 }
208 EXPORT_SYMBOL_GPL(crypto_poly1305_update);
209 
210 int crypto_poly1305_final(struct shash_desc *desc, u8 *dst)
211 {
212         struct poly1305_desc_ctx *dctx = shash_desc_ctx(desc);
213         __le32 *mac = (__le32 *)dst;
214         u32 h0, h1, h2, h3, h4;
215         u32 g0, g1, g2, g3, g4;
216         u32 mask;
217         u64 f = 0;
218 
219         if (unlikely(!dctx->sset))
220                 return -ENOKEY;
221 
222         if (unlikely(dctx->buflen)) {
223                 dctx->buf[dctx->buflen++] = 1;
224                 memset(dctx->buf + dctx->buflen, 0,
225                        POLY1305_BLOCK_SIZE - dctx->buflen);
226                 poly1305_blocks(dctx, dctx->buf, POLY1305_BLOCK_SIZE, 0);
227         }
228 
229         /* fully carry h */
230         h0 = dctx->h[0];
231         h1 = dctx->h[1];
232         h2 = dctx->h[2];
233         h3 = dctx->h[3];
234         h4 = dctx->h[4];
235 
236         h2 += (h1 >> 26);     h1 = h1 & 0x3ffffff;
237         h3 += (h2 >> 26);     h2 = h2 & 0x3ffffff;
238         h4 += (h3 >> 26);     h3 = h3 & 0x3ffffff;
239         h0 += (h4 >> 26) * 5; h4 = h4 & 0x3ffffff;
240         h1 += (h0 >> 26);     h0 = h0 & 0x3ffffff;
241 
242         /* compute h + -p */
243         g0 = h0 + 5;
244         g1 = h1 + (g0 >> 26);             g0 &= 0x3ffffff;
245         g2 = h2 + (g1 >> 26);             g1 &= 0x3ffffff;
246         g3 = h3 + (g2 >> 26);             g2 &= 0x3ffffff;
247         g4 = h4 + (g3 >> 26) - (1 << 26); g3 &= 0x3ffffff;
248 
249         /* select h if h < p, or h + -p if h >= p */
250         mask = (g4 >> ((sizeof(u32) * 8) - 1)) - 1;
251         g0 &= mask;
252         g1 &= mask;
253         g2 &= mask;
254         g3 &= mask;
255         g4 &= mask;
256         mask = ~mask;
257         h0 = (h0 & mask) | g0;
258         h1 = (h1 & mask) | g1;
259         h2 = (h2 & mask) | g2;
260         h3 = (h3 & mask) | g3;
261         h4 = (h4 & mask) | g4;
262 
263         /* h = h % (2^128) */
264         h0 = (h0 >>  0) | (h1 << 26);
265         h1 = (h1 >>  6) | (h2 << 20);
266         h2 = (h2 >> 12) | (h3 << 14);
267         h3 = (h3 >> 18) | (h4 <<  8);
268 
269         /* mac = (h + s) % (2^128) */
270         f = (f >> 32) + h0 + dctx->s[0]; mac[0] = cpu_to_le32(f);
271         f = (f >> 32) + h1 + dctx->s[1]; mac[1] = cpu_to_le32(f);
272         f = (f >> 32) + h2 + dctx->s[2]; mac[2] = cpu_to_le32(f);
273         f = (f >> 32) + h3 + dctx->s[3]; mac[3] = cpu_to_le32(f);
274 
275         return 0;
276 }
277 EXPORT_SYMBOL_GPL(crypto_poly1305_final);
278 
279 static struct shash_alg poly1305_alg = {
280         .digestsize     = POLY1305_DIGEST_SIZE,
281         .init           = crypto_poly1305_init,
282         .update         = crypto_poly1305_update,
283         .final          = crypto_poly1305_final,
284         .setkey         = crypto_poly1305_setkey,
285         .descsize       = sizeof(struct poly1305_desc_ctx),
286         .base           = {
287                 .cra_name               = "poly1305",
288                 .cra_driver_name        = "poly1305-generic",
289                 .cra_priority           = 100,
290                 .cra_flags              = CRYPTO_ALG_TYPE_SHASH,
291                 .cra_alignmask          = sizeof(u32) - 1,
292                 .cra_blocksize          = POLY1305_BLOCK_SIZE,
293                 .cra_module             = THIS_MODULE,
294         },
295 };
296 
297 static int __init poly1305_mod_init(void)
298 {
299         return crypto_register_shash(&poly1305_alg);
300 }
301 
302 static void __exit poly1305_mod_exit(void)
303 {
304         crypto_unregister_shash(&poly1305_alg);
305 }
306 
307 module_init(poly1305_mod_init);
308 module_exit(poly1305_mod_exit);
309 
310 MODULE_LICENSE("GPL");
311 MODULE_AUTHOR("Martin Willi <martin@strongswan.org>");
312 MODULE_DESCRIPTION("Poly1305 authenticator");
313 MODULE_ALIAS_CRYPTO("poly1305");
314 MODULE_ALIAS_CRYPTO("poly1305-generic");
315 

This page was automatically generated by LXR 0.3.1 (source).  •  Linux is a registered trademark of Linus Torvalds  •  Contact us