Root/crypto/vmac.c

1/*
2 * Modified to interface to the Linux kernel
3 * Copyright (c) 2009, Intel Corporation.
4 *
5 * This program is free software; you can redistribute it and/or modify it
6 * under the terms and conditions of the GNU General Public License,
7 * version 2, as published by the Free Software Foundation.
8 *
9 * This program is distributed in the hope it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
12 * more details.
13 *
14 * You should have received a copy of the GNU General Public License along with
15 * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
16 * Place - Suite 330, Boston, MA 02111-1307 USA.
17 */
18
19/* --------------------------------------------------------------------------
20 * VMAC and VHASH Implementation by Ted Krovetz (tdk@acm.org) and Wei Dai.
21 * This implementation is herby placed in the public domain.
22 * The authors offers no warranty. Use at your own risk.
23 * Please send bug reports to the authors.
24 * Last modified: 17 APR 08, 1700 PDT
25 * ----------------------------------------------------------------------- */
26
27#include <linux/init.h>
28#include <linux/types.h>
29#include <linux/crypto.h>
30#include <linux/module.h>
31#include <linux/scatterlist.h>
32#include <asm/byteorder.h>
33#include <crypto/scatterwalk.h>
34#include <crypto/vmac.h>
35#include <crypto/internal/hash.h>
36
37/*
38 * Constants and masks
39 */
40#define UINT64_C(x) x##ULL
41static const u64 p64 = UINT64_C(0xfffffffffffffeff); /* 2^64 - 257 prime */
42static const u64 m62 = UINT64_C(0x3fffffffffffffff); /* 62-bit mask */
43static const u64 m63 = UINT64_C(0x7fffffffffffffff); /* 63-bit mask */
44static const u64 m64 = UINT64_C(0xffffffffffffffff); /* 64-bit mask */
45static const u64 mpoly = UINT64_C(0x1fffffff1fffffff); /* Poly key mask */
46
47#define pe64_to_cpup le64_to_cpup /* Prefer little endian */
48
49#ifdef __LITTLE_ENDIAN
50#define INDEX_HIGH 1
51#define INDEX_LOW 0
52#else
53#define INDEX_HIGH 0
54#define INDEX_LOW 1
55#endif
56
57/*
58 * The following routines are used in this implementation. They are
59 * written via macros to simulate zero-overhead call-by-reference.
60 *
61 * MUL64: 64x64->128-bit multiplication
62 * PMUL64: assumes top bits cleared on inputs
63 * ADD128: 128x128->128-bit addition
64 */
65
66#define ADD128(rh, rl, ih, il) \
67    do { \
68        u64 _il = (il); \
69        (rl) += (_il); \
70        if ((rl) < (_il)) \
71            (rh)++; \
72        (rh) += (ih); \
73    } while (0)
74
75#define MUL32(i1, i2) ((u64)(u32)(i1)*(u32)(i2))
76
77#define PMUL64(rh, rl, i1, i2) /* Assumes m doesn't overflow */ \
78    do { \
79        u64 _i1 = (i1), _i2 = (i2); \
80        u64 m = MUL32(_i1, _i2>>32) + MUL32(_i1>>32, _i2); \
81        rh = MUL32(_i1>>32, _i2>>32); \
82        rl = MUL32(_i1, _i2); \
83        ADD128(rh, rl, (m >> 32), (m << 32)); \
84    } while (0)
85
86#define MUL64(rh, rl, i1, i2) \
87    do { \
88        u64 _i1 = (i1), _i2 = (i2); \
89        u64 m1 = MUL32(_i1, _i2>>32); \
90        u64 m2 = MUL32(_i1>>32, _i2); \
91        rh = MUL32(_i1>>32, _i2>>32); \
92        rl = MUL32(_i1, _i2); \
93        ADD128(rh, rl, (m1 >> 32), (m1 << 32)); \
94        ADD128(rh, rl, (m2 >> 32), (m2 << 32)); \
95    } while (0)
96
97/*
98 * For highest performance the L1 NH and L2 polynomial hashes should be
99 * carefully implemented to take advantage of one's target architecture.
100 * Here these two hash functions are defined multiple time; once for
101 * 64-bit architectures, once for 32-bit SSE2 architectures, and once
102 * for the rest (32-bit) architectures.
103 * For each, nh_16 *must* be defined (works on multiples of 16 bytes).
104 * Optionally, nh_vmac_nhbytes can be defined (for multiples of
105 * VMAC_NHBYTES), and nh_16_2 and nh_vmac_nhbytes_2 (versions that do two
106 * NH computations at once).
107 */
108
109#ifdef CONFIG_64BIT
110
111#define nh_16(mp, kp, nw, rh, rl) \
112    do { \
113        int i; u64 th, tl; \
114        rh = rl = 0; \
115        for (i = 0; i < nw; i += 2) { \
116            MUL64(th, tl, pe64_to_cpup((mp)+i)+(kp)[i], \
117                pe64_to_cpup((mp)+i+1)+(kp)[i+1]); \
118            ADD128(rh, rl, th, tl); \
119        } \
120    } while (0)
121
122#define nh_16_2(mp, kp, nw, rh, rl, rh1, rl1) \
123    do { \
124        int i; u64 th, tl; \
125        rh1 = rl1 = rh = rl = 0; \
126        for (i = 0; i < nw; i += 2) { \
127            MUL64(th, tl, pe64_to_cpup((mp)+i)+(kp)[i], \
128                pe64_to_cpup((mp)+i+1)+(kp)[i+1]); \
129            ADD128(rh, rl, th, tl); \
130            MUL64(th, tl, pe64_to_cpup((mp)+i)+(kp)[i+2], \
131                pe64_to_cpup((mp)+i+1)+(kp)[i+3]); \
132            ADD128(rh1, rl1, th, tl); \
133        } \
134    } while (0)
135
136#if (VMAC_NHBYTES >= 64) /* These versions do 64-bytes of message at a time */
137#define nh_vmac_nhbytes(mp, kp, nw, rh, rl) \
138    do { \
139        int i; u64 th, tl; \
140        rh = rl = 0; \
141        for (i = 0; i < nw; i += 8) { \
142            MUL64(th, tl, pe64_to_cpup((mp)+i)+(kp)[i], \
143                pe64_to_cpup((mp)+i+1)+(kp)[i+1]); \
144            ADD128(rh, rl, th, tl); \
145            MUL64(th, tl, pe64_to_cpup((mp)+i+2)+(kp)[i+2], \
146                pe64_to_cpup((mp)+i+3)+(kp)[i+3]); \
147            ADD128(rh, rl, th, tl); \
148            MUL64(th, tl, pe64_to_cpup((mp)+i+4)+(kp)[i+4], \
149                pe64_to_cpup((mp)+i+5)+(kp)[i+5]); \
150            ADD128(rh, rl, th, tl); \
151            MUL64(th, tl, pe64_to_cpup((mp)+i+6)+(kp)[i+6], \
152                pe64_to_cpup((mp)+i+7)+(kp)[i+7]); \
153            ADD128(rh, rl, th, tl); \
154        } \
155    } while (0)
156
157#define nh_vmac_nhbytes_2(mp, kp, nw, rh, rl, rh1, rl1) \
158    do { \
159        int i; u64 th, tl; \
160        rh1 = rl1 = rh = rl = 0; \
161        for (i = 0; i < nw; i += 8) { \
162            MUL64(th, tl, pe64_to_cpup((mp)+i)+(kp)[i], \
163                pe64_to_cpup((mp)+i+1)+(kp)[i+1]); \
164            ADD128(rh, rl, th, tl); \
165            MUL64(th, tl, pe64_to_cpup((mp)+i)+(kp)[i+2], \
166                pe64_to_cpup((mp)+i+1)+(kp)[i+3]); \
167            ADD128(rh1, rl1, th, tl); \
168            MUL64(th, tl, pe64_to_cpup((mp)+i+2)+(kp)[i+2], \
169                pe64_to_cpup((mp)+i+3)+(kp)[i+3]); \
170            ADD128(rh, rl, th, tl); \
171            MUL64(th, tl, pe64_to_cpup((mp)+i+2)+(kp)[i+4], \
172                pe64_to_cpup((mp)+i+3)+(kp)[i+5]); \
173            ADD128(rh1, rl1, th, tl); \
174            MUL64(th, tl, pe64_to_cpup((mp)+i+4)+(kp)[i+4], \
175                pe64_to_cpup((mp)+i+5)+(kp)[i+5]); \
176            ADD128(rh, rl, th, tl); \
177            MUL64(th, tl, pe64_to_cpup((mp)+i+4)+(kp)[i+6], \
178                pe64_to_cpup((mp)+i+5)+(kp)[i+7]); \
179            ADD128(rh1, rl1, th, tl); \
180            MUL64(th, tl, pe64_to_cpup((mp)+i+6)+(kp)[i+6], \
181                pe64_to_cpup((mp)+i+7)+(kp)[i+7]); \
182            ADD128(rh, rl, th, tl); \
183            MUL64(th, tl, pe64_to_cpup((mp)+i+6)+(kp)[i+8], \
184                pe64_to_cpup((mp)+i+7)+(kp)[i+9]); \
185            ADD128(rh1, rl1, th, tl); \
186        } \
187    } while (0)
188#endif
189
190#define poly_step(ah, al, kh, kl, mh, ml) \
191    do { \
192        u64 t1h, t1l, t2h, t2l, t3h, t3l, z = 0; \
193        /* compute ab*cd, put bd into result registers */ \
194        PMUL64(t3h, t3l, al, kh); \
195        PMUL64(t2h, t2l, ah, kl); \
196        PMUL64(t1h, t1l, ah, 2*kh); \
197        PMUL64(ah, al, al, kl); \
198        /* add 2 * ac to result */ \
199        ADD128(ah, al, t1h, t1l); \
200        /* add together ad + bc */ \
201        ADD128(t2h, t2l, t3h, t3l); \
202        /* now (ah,al), (t2l,2*t2h) need summing */ \
203        /* first add the high registers, carrying into t2h */ \
204        ADD128(t2h, ah, z, t2l); \
205        /* double t2h and add top bit of ah */ \
206        t2h = 2 * t2h + (ah >> 63); \
207        ah &= m63; \
208        /* now add the low registers */ \
209        ADD128(ah, al, mh, ml); \
210        ADD128(ah, al, z, t2h); \
211    } while (0)
212
213#else /* ! CONFIG_64BIT */
214
215#ifndef nh_16
216#define nh_16(mp, kp, nw, rh, rl) \
217    do { \
218        u64 t1, t2, m1, m2, t; \
219        int i; \
220        rh = rl = t = 0; \
221        for (i = 0; i < nw; i += 2) { \
222            t1 = pe64_to_cpup(mp+i) + kp[i]; \
223            t2 = pe64_to_cpup(mp+i+1) + kp[i+1]; \
224            m2 = MUL32(t1 >> 32, t2); \
225            m1 = MUL32(t1, t2 >> 32); \
226            ADD128(rh, rl, MUL32(t1 >> 32, t2 >> 32), \
227                MUL32(t1, t2)); \
228            rh += (u64)(u32)(m1 >> 32) \
229                + (u32)(m2 >> 32); \
230            t += (u64)(u32)m1 + (u32)m2; \
231        } \
232        ADD128(rh, rl, (t >> 32), (t << 32)); \
233    } while (0)
234#endif
235
236static void poly_step_func(u64 *ahi, u64 *alo,
237            const u64 *kh, const u64 *kl,
238            const u64 *mh, const u64 *ml)
239{
240#define a0 (*(((u32 *)alo)+INDEX_LOW))
241#define a1 (*(((u32 *)alo)+INDEX_HIGH))
242#define a2 (*(((u32 *)ahi)+INDEX_LOW))
243#define a3 (*(((u32 *)ahi)+INDEX_HIGH))
244#define k0 (*(((u32 *)kl)+INDEX_LOW))
245#define k1 (*(((u32 *)kl)+INDEX_HIGH))
246#define k2 (*(((u32 *)kh)+INDEX_LOW))
247#define k3 (*(((u32 *)kh)+INDEX_HIGH))
248
249    u64 p, q, t;
250    u32 t2;
251
252    p = MUL32(a3, k3);
253    p += p;
254    p += *(u64 *)mh;
255    p += MUL32(a0, k2);
256    p += MUL32(a1, k1);
257    p += MUL32(a2, k0);
258    t = (u32)(p);
259    p >>= 32;
260    p += MUL32(a0, k3);
261    p += MUL32(a1, k2);
262    p += MUL32(a2, k1);
263    p += MUL32(a3, k0);
264    t |= ((u64)((u32)p & 0x7fffffff)) << 32;
265    p >>= 31;
266    p += (u64)(((u32 *)ml)[INDEX_LOW]);
267    p += MUL32(a0, k0);
268    q = MUL32(a1, k3);
269    q += MUL32(a2, k2);
270    q += MUL32(a3, k1);
271    q += q;
272    p += q;
273    t2 = (u32)(p);
274    p >>= 32;
275    p += (u64)(((u32 *)ml)[INDEX_HIGH]);
276    p += MUL32(a0, k1);
277    p += MUL32(a1, k0);
278    q = MUL32(a2, k3);
279    q += MUL32(a3, k2);
280    q += q;
281    p += q;
282    *(u64 *)(alo) = (p << 32) | t2;
283    p >>= 32;
284    *(u64 *)(ahi) = p + t;
285
286#undef a0
287#undef a1
288#undef a2
289#undef a3
290#undef k0
291#undef k1
292#undef k2
293#undef k3
294}
295
296#define poly_step(ah, al, kh, kl, mh, ml) \
297    poly_step_func(&(ah), &(al), &(kh), &(kl), &(mh), &(ml))
298
299#endif /* end of specialized NH and poly definitions */
300
301/* At least nh_16 is defined. Defined others as needed here */
302#ifndef nh_16_2
303#define nh_16_2(mp, kp, nw, rh, rl, rh2, rl2) \
304    do { \
305        nh_16(mp, kp, nw, rh, rl); \
306        nh_16(mp, ((kp)+2), nw, rh2, rl2); \
307    } while (0)
308#endif
309#ifndef nh_vmac_nhbytes
310#define nh_vmac_nhbytes(mp, kp, nw, rh, rl) \
311    nh_16(mp, kp, nw, rh, rl)
312#endif
313#ifndef nh_vmac_nhbytes_2
314#define nh_vmac_nhbytes_2(mp, kp, nw, rh, rl, rh2, rl2) \
315    do { \
316        nh_vmac_nhbytes(mp, kp, nw, rh, rl); \
317        nh_vmac_nhbytes(mp, ((kp)+2), nw, rh2, rl2); \
318    } while (0)
319#endif
320
321static void vhash_abort(struct vmac_ctx *ctx)
322{
323    ctx->polytmp[0] = ctx->polykey[0] ;
324    ctx->polytmp[1] = ctx->polykey[1] ;
325    ctx->first_block_processed = 0;
326}
327
328static u64 l3hash(u64 p1, u64 p2, u64 k1, u64 k2, u64 len)
329{
330    u64 rh, rl, t, z = 0;
331
332    /* fully reduce (p1,p2)+(len,0) mod p127 */
333    t = p1 >> 63;
334    p1 &= m63;
335    ADD128(p1, p2, len, t);
336    /* At this point, (p1,p2) is at most 2^127+(len<<64) */
337    t = (p1 > m63) + ((p1 == m63) && (p2 == m64));
338    ADD128(p1, p2, z, t);
339    p1 &= m63;
340
341    /* compute (p1,p2)/(2^64-2^32) and (p1,p2)%(2^64-2^32) */
342    t = p1 + (p2 >> 32);
343    t += (t >> 32);
344    t += (u32)t > 0xfffffffeu;
345    p1 += (t >> 32);
346    p2 += (p1 << 32);
347
348    /* compute (p1+k1)%p64 and (p2+k2)%p64 */
349    p1 += k1;
350    p1 += (0 - (p1 < k1)) & 257;
351    p2 += k2;
352    p2 += (0 - (p2 < k2)) & 257;
353
354    /* compute (p1+k1)*(p2+k2)%p64 */
355    MUL64(rh, rl, p1, p2);
356    t = rh >> 56;
357    ADD128(t, rl, z, rh);
358    rh <<= 8;
359    ADD128(t, rl, z, rh);
360    t += t << 8;
361    rl += t;
362    rl += (0 - (rl < t)) & 257;
363    rl += (0 - (rl > p64-1)) & 257;
364    return rl;
365}
366
367static void vhash_update(const unsigned char *m,
368            unsigned int mbytes, /* Pos multiple of VMAC_NHBYTES */
369            struct vmac_ctx *ctx)
370{
371    u64 rh, rl, *mptr;
372    const u64 *kptr = (u64 *)ctx->nhkey;
373    int i;
374    u64 ch, cl;
375    u64 pkh = ctx->polykey[0];
376    u64 pkl = ctx->polykey[1];
377
378    if (!mbytes)
379        return;
380
381    BUG_ON(mbytes % VMAC_NHBYTES);
382
383    mptr = (u64 *)m;
384    i = mbytes / VMAC_NHBYTES; /* Must be non-zero */
385
386    ch = ctx->polytmp[0];
387    cl = ctx->polytmp[1];
388
389    if (!ctx->first_block_processed) {
390        ctx->first_block_processed = 1;
391        nh_vmac_nhbytes(mptr, kptr, VMAC_NHBYTES/8, rh, rl);
392        rh &= m62;
393        ADD128(ch, cl, rh, rl);
394        mptr += (VMAC_NHBYTES/sizeof(u64));
395        i--;
396    }
397
398    while (i--) {
399        nh_vmac_nhbytes(mptr, kptr, VMAC_NHBYTES/8, rh, rl);
400        rh &= m62;
401        poly_step(ch, cl, pkh, pkl, rh, rl);
402        mptr += (VMAC_NHBYTES/sizeof(u64));
403    }
404
405    ctx->polytmp[0] = ch;
406    ctx->polytmp[1] = cl;
407}
408
409static u64 vhash(unsigned char m[], unsigned int mbytes,
410            u64 *tagl, struct vmac_ctx *ctx)
411{
412    u64 rh, rl, *mptr;
413    const u64 *kptr = (u64 *)ctx->nhkey;
414    int i, remaining;
415    u64 ch, cl;
416    u64 pkh = ctx->polykey[0];
417    u64 pkl = ctx->polykey[1];
418
419    mptr = (u64 *)m;
420    i = mbytes / VMAC_NHBYTES;
421    remaining = mbytes % VMAC_NHBYTES;
422
423    if (ctx->first_block_processed) {
424        ch = ctx->polytmp[0];
425        cl = ctx->polytmp[1];
426    } else if (i) {
427        nh_vmac_nhbytes(mptr, kptr, VMAC_NHBYTES/8, ch, cl);
428        ch &= m62;
429        ADD128(ch, cl, pkh, pkl);
430        mptr += (VMAC_NHBYTES/sizeof(u64));
431        i--;
432    } else if (remaining) {
433        nh_16(mptr, kptr, 2*((remaining+15)/16), ch, cl);
434        ch &= m62;
435        ADD128(ch, cl, pkh, pkl);
436        mptr += (VMAC_NHBYTES/sizeof(u64));
437        goto do_l3;
438    } else {/* Empty String */
439        ch = pkh; cl = pkl;
440        goto do_l3;
441    }
442
443    while (i--) {
444        nh_vmac_nhbytes(mptr, kptr, VMAC_NHBYTES/8, rh, rl);
445        rh &= m62;
446        poly_step(ch, cl, pkh, pkl, rh, rl);
447        mptr += (VMAC_NHBYTES/sizeof(u64));
448    }
449    if (remaining) {
450        nh_16(mptr, kptr, 2*((remaining+15)/16), rh, rl);
451        rh &= m62;
452        poly_step(ch, cl, pkh, pkl, rh, rl);
453    }
454
455do_l3:
456    vhash_abort(ctx);
457    remaining *= 8;
458    return l3hash(ch, cl, ctx->l3key[0], ctx->l3key[1], remaining);
459}
460
461static u64 vmac(unsigned char m[], unsigned int mbytes,
462            const unsigned char n[16], u64 *tagl,
463            struct vmac_ctx_t *ctx)
464{
465    u64 *in_n, *out_p;
466    u64 p, h;
467    int i;
468
469    in_n = ctx->__vmac_ctx.cached_nonce;
470    out_p = ctx->__vmac_ctx.cached_aes;
471
472    i = n[15] & 1;
473    if ((*(u64 *)(n+8) != in_n[1]) || (*(u64 *)(n) != in_n[0])) {
474        in_n[0] = *(u64 *)(n);
475        in_n[1] = *(u64 *)(n+8);
476        ((unsigned char *)in_n)[15] &= 0xFE;
477        crypto_cipher_encrypt_one(ctx->child,
478            (unsigned char *)out_p, (unsigned char *)in_n);
479
480        ((unsigned char *)in_n)[15] |= (unsigned char)(1-i);
481    }
482    p = be64_to_cpup(out_p + i);
483    h = vhash(m, mbytes, (u64 *)0, &ctx->__vmac_ctx);
484    return le64_to_cpu(p + h);
485}
486
487static int vmac_set_key(unsigned char user_key[], struct vmac_ctx_t *ctx)
488{
489    u64 in[2] = {0}, out[2];
490    unsigned i;
491    int err = 0;
492
493    err = crypto_cipher_setkey(ctx->child, user_key, VMAC_KEY_LEN);
494    if (err)
495        return err;
496
497    /* Fill nh key */
498    ((unsigned char *)in)[0] = 0x80;
499    for (i = 0; i < sizeof(ctx->__vmac_ctx.nhkey)/8; i += 2) {
500        crypto_cipher_encrypt_one(ctx->child,
501            (unsigned char *)out, (unsigned char *)in);
502        ctx->__vmac_ctx.nhkey[i] = be64_to_cpup(out);
503        ctx->__vmac_ctx.nhkey[i+1] = be64_to_cpup(out+1);
504        ((unsigned char *)in)[15] += 1;
505    }
506
507    /* Fill poly key */
508    ((unsigned char *)in)[0] = 0xC0;
509    in[1] = 0;
510    for (i = 0; i < sizeof(ctx->__vmac_ctx.polykey)/8; i += 2) {
511        crypto_cipher_encrypt_one(ctx->child,
512            (unsigned char *)out, (unsigned char *)in);
513        ctx->__vmac_ctx.polytmp[i] =
514            ctx->__vmac_ctx.polykey[i] =
515                be64_to_cpup(out) & mpoly;
516        ctx->__vmac_ctx.polytmp[i+1] =
517            ctx->__vmac_ctx.polykey[i+1] =
518                be64_to_cpup(out+1) & mpoly;
519        ((unsigned char *)in)[15] += 1;
520    }
521
522    /* Fill ip key */
523    ((unsigned char *)in)[0] = 0xE0;
524    in[1] = 0;
525    for (i = 0; i < sizeof(ctx->__vmac_ctx.l3key)/8; i += 2) {
526        do {
527            crypto_cipher_encrypt_one(ctx->child,
528                (unsigned char *)out, (unsigned char *)in);
529            ctx->__vmac_ctx.l3key[i] = be64_to_cpup(out);
530            ctx->__vmac_ctx.l3key[i+1] = be64_to_cpup(out+1);
531            ((unsigned char *)in)[15] += 1;
532        } while (ctx->__vmac_ctx.l3key[i] >= p64
533            || ctx->__vmac_ctx.l3key[i+1] >= p64);
534    }
535
536    /* Invalidate nonce/aes cache and reset other elements */
537    ctx->__vmac_ctx.cached_nonce[0] = (u64)-1; /* Ensure illegal nonce */
538    ctx->__vmac_ctx.cached_nonce[1] = (u64)0; /* Ensure illegal nonce */
539    ctx->__vmac_ctx.first_block_processed = 0;
540
541    return err;
542}
543
544static int vmac_setkey(struct crypto_shash *parent,
545        const u8 *key, unsigned int keylen)
546{
547    struct vmac_ctx_t *ctx = crypto_shash_ctx(parent);
548
549    if (keylen != VMAC_KEY_LEN) {
550        crypto_shash_set_flags(parent, CRYPTO_TFM_RES_BAD_KEY_LEN);
551        return -EINVAL;
552    }
553
554    return vmac_set_key((u8 *)key, ctx);
555}
556
557static int vmac_init(struct shash_desc *pdesc)
558{
559    return 0;
560}
561
562static int vmac_update(struct shash_desc *pdesc, const u8 *p,
563        unsigned int len)
564{
565    struct crypto_shash *parent = pdesc->tfm;
566    struct vmac_ctx_t *ctx = crypto_shash_ctx(parent);
567    int expand;
568    int min;
569
570    expand = VMAC_NHBYTES - ctx->partial_size > 0 ?
571            VMAC_NHBYTES - ctx->partial_size : 0;
572
573    min = len < expand ? len : expand;
574
575    memcpy(ctx->partial + ctx->partial_size, p, min);
576    ctx->partial_size += min;
577
578    if (len < expand)
579        return 0;
580
581    vhash_update(ctx->partial, VMAC_NHBYTES, &ctx->__vmac_ctx);
582    ctx->partial_size = 0;
583
584    len -= expand;
585    p += expand;
586
587    if (len % VMAC_NHBYTES) {
588        memcpy(ctx->partial, p + len - (len % VMAC_NHBYTES),
589            len % VMAC_NHBYTES);
590        ctx->partial_size = len % VMAC_NHBYTES;
591    }
592
593    vhash_update(p, len - len % VMAC_NHBYTES, &ctx->__vmac_ctx);
594
595    return 0;
596}
597
598static int vmac_final(struct shash_desc *pdesc, u8 *out)
599{
600    struct crypto_shash *parent = pdesc->tfm;
601    struct vmac_ctx_t *ctx = crypto_shash_ctx(parent);
602    vmac_t mac;
603    u8 nonce[16] = {};
604
605    /* vmac() ends up accessing outside the array bounds that
606     * we specify. In appears to access up to the next 2-word
607     * boundary. We'll just be uber cautious and zero the
608     * unwritten bytes in the buffer.
609     */
610    if (ctx->partial_size) {
611        memset(ctx->partial + ctx->partial_size, 0,
612            VMAC_NHBYTES - ctx->partial_size);
613    }
614    mac = vmac(ctx->partial, ctx->partial_size, nonce, NULL, ctx);
615    memcpy(out, &mac, sizeof(vmac_t));
616    memzero_explicit(&mac, sizeof(vmac_t));
617    memset(&ctx->__vmac_ctx, 0, sizeof(struct vmac_ctx));
618    ctx->partial_size = 0;
619    return 0;
620}
621
622static int vmac_init_tfm(struct crypto_tfm *tfm)
623{
624    struct crypto_cipher *cipher;
625    struct crypto_instance *inst = (void *)tfm->__crt_alg;
626    struct crypto_spawn *spawn = crypto_instance_ctx(inst);
627    struct vmac_ctx_t *ctx = crypto_tfm_ctx(tfm);
628
629    cipher = crypto_spawn_cipher(spawn);
630    if (IS_ERR(cipher))
631        return PTR_ERR(cipher);
632
633    ctx->child = cipher;
634    return 0;
635}
636
637static void vmac_exit_tfm(struct crypto_tfm *tfm)
638{
639    struct vmac_ctx_t *ctx = crypto_tfm_ctx(tfm);
640    crypto_free_cipher(ctx->child);
641}
642
643static int vmac_create(struct crypto_template *tmpl, struct rtattr **tb)
644{
645    struct shash_instance *inst;
646    struct crypto_alg *alg;
647    int err;
648
649    err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_SHASH);
650    if (err)
651        return err;
652
653    alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_CIPHER,
654            CRYPTO_ALG_TYPE_MASK);
655    if (IS_ERR(alg))
656        return PTR_ERR(alg);
657
658    inst = shash_alloc_instance("vmac", alg);
659    err = PTR_ERR(inst);
660    if (IS_ERR(inst))
661        goto out_put_alg;
662
663    err = crypto_init_spawn(shash_instance_ctx(inst), alg,
664            shash_crypto_instance(inst),
665            CRYPTO_ALG_TYPE_MASK);
666    if (err)
667        goto out_free_inst;
668
669    inst->alg.base.cra_priority = alg->cra_priority;
670    inst->alg.base.cra_blocksize = alg->cra_blocksize;
671    inst->alg.base.cra_alignmask = alg->cra_alignmask;
672
673    inst->alg.digestsize = sizeof(vmac_t);
674    inst->alg.base.cra_ctxsize = sizeof(struct vmac_ctx_t);
675    inst->alg.base.cra_init = vmac_init_tfm;
676    inst->alg.base.cra_exit = vmac_exit_tfm;
677
678    inst->alg.init = vmac_init;
679    inst->alg.update = vmac_update;
680    inst->alg.final = vmac_final;
681    inst->alg.setkey = vmac_setkey;
682
683    err = shash_register_instance(tmpl, inst);
684    if (err) {
685out_free_inst:
686        shash_free_instance(shash_crypto_instance(inst));
687    }
688
689out_put_alg:
690    crypto_mod_put(alg);
691    return err;
692}
693
694static struct crypto_template vmac_tmpl = {
695    .name = "vmac",
696    .create = vmac_create,
697    .free = shash_free_instance,
698    .module = THIS_MODULE,
699};
700
701static int __init vmac_module_init(void)
702{
703    return crypto_register_template(&vmac_tmpl);
704}
705
706static void __exit vmac_module_exit(void)
707{
708    crypto_unregister_template(&vmac_tmpl);
709}
710
711module_init(vmac_module_init);
712module_exit(vmac_module_exit);
713
714MODULE_LICENSE("GPL");
715MODULE_DESCRIPTION("VMAC hash algorithm");
716

Archive Download this file



interactive