Skip to content
This repository

HTTPS clone URL

Subversion checkout URL

You can clone with HTTPS or Subversion.

Download ZIP
tag: v2.6.13-rc6
Fetching contributors…

Cannot retrieve contributors at this time

file 461 lines (372 sloc) 11.347 kb
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461
/*
* Cryptographic API.
*
* Cipher operations.
*
* Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
* Copyright (c) 2005 Herbert Xu <herbert@gondor.apana.org.au>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the Free
* Software Foundation; either version 2 of the License, or (at your option)
* any later version.
*
*/
#include <linux/compiler.h>
#include <linux/kernel.h>
#include <linux/crypto.h>
#include <linux/errno.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <asm/scatterlist.h>
#include "internal.h"
#include "scatterwalk.h"

static inline void xor_64(u8 *a, const u8 *b)
{
((u32 *)a)[0] ^= ((u32 *)b)[0];
((u32 *)a)[1] ^= ((u32 *)b)[1];
}

static inline void xor_128(u8 *a, const u8 *b)
{
((u32 *)a)[0] ^= ((u32 *)b)[0];
((u32 *)a)[1] ^= ((u32 *)b)[1];
((u32 *)a)[2] ^= ((u32 *)b)[2];
((u32 *)a)[3] ^= ((u32 *)b)[3];
}

static unsigned int crypt_slow(const struct cipher_desc *desc,
struct scatter_walk *in,
struct scatter_walk *out, unsigned int bsize)
{
unsigned long alignmask = crypto_tfm_alg_alignmask(desc->tfm);
u8 buffer[bsize * 2 + alignmask];
u8 *src = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
u8 *dst = src + bsize;
unsigned int n;

n = scatterwalk_copychunks(src, in, bsize, 0);
scatterwalk_advance(in, n);

desc->prfn(desc, dst, src, bsize);

n = scatterwalk_copychunks(dst, out, bsize, 1);
scatterwalk_advance(out, n);

return bsize;
}

static inline unsigned int crypt_fast(const struct cipher_desc *desc,
struct scatter_walk *in,
struct scatter_walk *out,
unsigned int nbytes, u8 *tmp)
{
u8 *src, *dst;

src = in->data;
dst = scatterwalk_samebuf(in, out) ? src : out->data;

if (tmp) {
memcpy(tmp, in->data, nbytes);
src = tmp;
dst = tmp;
}

nbytes = desc->prfn(desc, dst, src, nbytes);

if (tmp)
memcpy(out->data, tmp, nbytes);

scatterwalk_advance(in, nbytes);
scatterwalk_advance(out, nbytes);

return nbytes;
}

/*
* Generic encrypt/decrypt wrapper for ciphers, handles operations across
* multiple page boundaries by using temporary blocks. In user context,
* the kernel is given a chance to schedule us once per page.
*/
static int crypt(const struct cipher_desc *desc,
struct scatterlist *dst,
struct scatterlist *src,
unsigned int nbytes)
{
struct scatter_walk walk_in, walk_out;
struct crypto_tfm *tfm = desc->tfm;
const unsigned int bsize = crypto_tfm_alg_blocksize(tfm);
unsigned int alignmask = crypto_tfm_alg_alignmask(tfm);
unsigned long buffer = 0;

if (!nbytes)
return 0;

if (nbytes % bsize) {
tfm->crt_flags |= CRYPTO_TFM_RES_BAD_BLOCK_LEN;
return -EINVAL;
}

scatterwalk_start(&walk_in, src);
scatterwalk_start(&walk_out, dst);

for(;;) {
unsigned int n = nbytes;
u8 *tmp = NULL;

if (!scatterwalk_aligned(&walk_in, alignmask) ||
!scatterwalk_aligned(&walk_out, alignmask)) {
if (!buffer) {
buffer = __get_free_page(GFP_ATOMIC);
if (!buffer)
n = 0;
}
tmp = (u8 *)buffer;
}

scatterwalk_map(&walk_in, 0);
scatterwalk_map(&walk_out, 1);

n = scatterwalk_clamp(&walk_in, n);
n = scatterwalk_clamp(&walk_out, n);

if (likely(n >= bsize))
n = crypt_fast(desc, &walk_in, &walk_out, n, tmp);
else
n = crypt_slow(desc, &walk_in, &walk_out, bsize);

nbytes -= n;

scatterwalk_done(&walk_in, 0, nbytes);
scatterwalk_done(&walk_out, 1, nbytes);

if (!nbytes)
break;

crypto_yield(tfm);
}

if (buffer)
free_page(buffer);

return 0;
}

static int crypt_iv_unaligned(struct cipher_desc *desc,
struct scatterlist *dst,
struct scatterlist *src,
unsigned int nbytes)
{
struct crypto_tfm *tfm = desc->tfm;
unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
u8 *iv = desc->info;

if (unlikely(((unsigned long)iv & alignmask))) {
unsigned int ivsize = tfm->crt_cipher.cit_ivsize;
u8 buffer[ivsize + alignmask];
u8 *tmp = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
int err;

desc->info = memcpy(tmp, iv, ivsize);
err = crypt(desc, dst, src, nbytes);
memcpy(iv, tmp, ivsize);

return err;
}

return crypt(desc, dst, src, nbytes);
}

static unsigned int cbc_process_encrypt(const struct cipher_desc *desc,
u8 *dst, const u8 *src,
unsigned int nbytes)
{
struct crypto_tfm *tfm = desc->tfm;
void (*xor)(u8 *, const u8 *) = tfm->crt_u.cipher.cit_xor_block;
int bsize = crypto_tfm_alg_blocksize(tfm);

void (*fn)(void *, u8 *, const u8 *) = desc->crfn;
u8 *iv = desc->info;
unsigned int done = 0;

do {
xor(iv, src);
fn(crypto_tfm_ctx(tfm), dst, iv);
memcpy(iv, dst, bsize);

src += bsize;
dst += bsize;
} while ((done += bsize) < nbytes);

return done;
}

static unsigned int cbc_process_decrypt(const struct cipher_desc *desc,
u8 *dst, const u8 *src,
unsigned int nbytes)
{
struct crypto_tfm *tfm = desc->tfm;
void (*xor)(u8 *, const u8 *) = tfm->crt_u.cipher.cit_xor_block;
int bsize = crypto_tfm_alg_blocksize(tfm);

u8 stack[src == dst ? bsize : 0];
u8 *buf = stack;
u8 **dst_p = src == dst ? &buf : &dst;

void (*fn)(void *, u8 *, const u8 *) = desc->crfn;
u8 *iv = desc->info;
unsigned int done = 0;

do {
u8 *tmp_dst = *dst_p;

fn(crypto_tfm_ctx(tfm), tmp_dst, src);
xor(tmp_dst, iv);
memcpy(iv, src, bsize);
if (tmp_dst != dst)
memcpy(dst, tmp_dst, bsize);

src += bsize;
dst += bsize;
} while ((done += bsize) < nbytes);

return done;
}

static unsigned int ecb_process(const struct cipher_desc *desc, u8 *dst,
const u8 *src, unsigned int nbytes)
{
struct crypto_tfm *tfm = desc->tfm;
int bsize = crypto_tfm_alg_blocksize(tfm);
void (*fn)(void *, u8 *, const u8 *) = desc->crfn;
unsigned int done = 0;

do {
fn(crypto_tfm_ctx(tfm), dst, src);

src += bsize;
dst += bsize;
} while ((done += bsize) < nbytes);

return done;
}

static int setkey(struct crypto_tfm *tfm, const u8 *key, unsigned int keylen)
{
struct cipher_alg *cia = &tfm->__crt_alg->cra_cipher;

if (keylen < cia->cia_min_keysize || keylen > cia->cia_max_keysize) {
tfm->crt_flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
return -EINVAL;
} else
return cia->cia_setkey(crypto_tfm_ctx(tfm), key, keylen,
&tfm->crt_flags);
}

static int ecb_encrypt(struct crypto_tfm *tfm,
struct scatterlist *dst,
                       struct scatterlist *src, unsigned int nbytes)
{
struct cipher_desc desc;
struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher;

desc.tfm = tfm;
desc.crfn = cipher->cia_encrypt;
desc.prfn = cipher->cia_encrypt_ecb ?: ecb_process;

return crypt(&desc, dst, src, nbytes);
}

static int ecb_decrypt(struct crypto_tfm *tfm,
                       struct scatterlist *dst,
                       struct scatterlist *src,
unsigned int nbytes)
{
struct cipher_desc desc;
struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher;

desc.tfm = tfm;
desc.crfn = cipher->cia_decrypt;
desc.prfn = cipher->cia_decrypt_ecb ?: ecb_process;

return crypt(&desc, dst, src, nbytes);
}

static int cbc_encrypt(struct crypto_tfm *tfm,
                       struct scatterlist *dst,
                       struct scatterlist *src,
unsigned int nbytes)
{
struct cipher_desc desc;
struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher;

desc.tfm = tfm;
desc.crfn = cipher->cia_encrypt;
desc.prfn = cipher->cia_encrypt_cbc ?: cbc_process_encrypt;
desc.info = tfm->crt_cipher.cit_iv;

return crypt(&desc, dst, src, nbytes);
}

static int cbc_encrypt_iv(struct crypto_tfm *tfm,
                          struct scatterlist *dst,
                          struct scatterlist *src,
                          unsigned int nbytes, u8 *iv)
{
struct cipher_desc desc;
struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher;

desc.tfm = tfm;
desc.crfn = cipher->cia_encrypt;
desc.prfn = cipher->cia_encrypt_cbc ?: cbc_process_encrypt;
desc.info = iv;

return crypt_iv_unaligned(&desc, dst, src, nbytes);
}

static int cbc_decrypt(struct crypto_tfm *tfm,
                       struct scatterlist *dst,
                       struct scatterlist *src,
unsigned int nbytes)
{
struct cipher_desc desc;
struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher;

desc.tfm = tfm;
desc.crfn = cipher->cia_decrypt;
desc.prfn = cipher->cia_decrypt_cbc ?: cbc_process_decrypt;
desc.info = tfm->crt_cipher.cit_iv;

return crypt(&desc, dst, src, nbytes);
}

static int cbc_decrypt_iv(struct crypto_tfm *tfm,
                          struct scatterlist *dst,
                          struct scatterlist *src,
                          unsigned int nbytes, u8 *iv)
{
struct cipher_desc desc;
struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher;

desc.tfm = tfm;
desc.crfn = cipher->cia_decrypt;
desc.prfn = cipher->cia_decrypt_cbc ?: cbc_process_decrypt;
desc.info = iv;

return crypt_iv_unaligned(&desc, dst, src, nbytes);
}

static int nocrypt(struct crypto_tfm *tfm,
                   struct scatterlist *dst,
                   struct scatterlist *src,
unsigned int nbytes)
{
return -ENOSYS;
}

static int nocrypt_iv(struct crypto_tfm *tfm,
                      struct scatterlist *dst,
                      struct scatterlist *src,
                      unsigned int nbytes, u8 *iv)
{
return -ENOSYS;
}

int crypto_init_cipher_flags(struct crypto_tfm *tfm, u32 flags)
{
u32 mode = flags & CRYPTO_TFM_MODE_MASK;

tfm->crt_cipher.cit_mode = mode ? mode : CRYPTO_TFM_MODE_ECB;
if (flags & CRYPTO_TFM_REQ_WEAK_KEY)
tfm->crt_flags = CRYPTO_TFM_REQ_WEAK_KEY;

return 0;
}

int crypto_init_cipher_ops(struct crypto_tfm *tfm)
{
int ret = 0;
struct cipher_tfm *ops = &tfm->crt_cipher;

ops->cit_setkey = setkey;

switch (tfm->crt_cipher.cit_mode) {
case CRYPTO_TFM_MODE_ECB:
ops->cit_encrypt = ecb_encrypt;
ops->cit_decrypt = ecb_decrypt;
break;

case CRYPTO_TFM_MODE_CBC:
ops->cit_encrypt = cbc_encrypt;
ops->cit_decrypt = cbc_decrypt;
ops->cit_encrypt_iv = cbc_encrypt_iv;
ops->cit_decrypt_iv = cbc_decrypt_iv;
break;

case CRYPTO_TFM_MODE_CFB:
ops->cit_encrypt = nocrypt;
ops->cit_decrypt = nocrypt;
ops->cit_encrypt_iv = nocrypt_iv;
ops->cit_decrypt_iv = nocrypt_iv;
break;

case CRYPTO_TFM_MODE_CTR:
ops->cit_encrypt = nocrypt;
ops->cit_decrypt = nocrypt;
ops->cit_encrypt_iv = nocrypt_iv;
ops->cit_decrypt_iv = nocrypt_iv;
break;

default:
BUG();
}

if (ops->cit_mode == CRYPTO_TFM_MODE_CBC) {
unsigned long align;
unsigned long addr;

switch (crypto_tfm_alg_blocksize(tfm)) {
case 8:
ops->cit_xor_block = xor_64;
break;

case 16:
ops->cit_xor_block = xor_128;
break;

default:
printk(KERN_WARNING "%s: block size %u not supported\n",
crypto_tfm_alg_name(tfm),
crypto_tfm_alg_blocksize(tfm));
ret = -EINVAL;
goto out;
}

ops->cit_ivsize = crypto_tfm_alg_blocksize(tfm);
align = crypto_tfm_alg_alignmask(tfm) + 1;
addr = (unsigned long)crypto_tfm_ctx(tfm);
addr = ALIGN(addr, align);
addr += ALIGN(tfm->__crt_alg->cra_ctxsize, align);
ops->cit_iv = (void *)addr;
}

out:
return ret;
}

void crypto_exit_cipher_ops(struct crypto_tfm *tfm)
{
}
Something went wrong with that request. Please try again.