1/* 2 * Block chaining cipher operations. 3 * 4 * Generic encrypt/decrypt wrapper for ciphers, handles operations across 5 * multiple page boundaries by using temporary blocks. In user context, 6 * the kernel is given a chance to schedule us once per page. 7 * 8 * Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au> 9 * 10 * This program is free software; you can redistribute it and/or modify it 11 * under the terms of the GNU General Public License as published by the Free 12 * Software Foundation; either version 2 of the License, or (at your option) 13 * any later version. 14 * 15 */ 16 17#include <linux/crypto.h> 18#include <linux/errno.h> 19#include <linux/hardirq.h> 20#include <linux/kernel.h> 21#include <linux/module.h> 22#include <linux/scatterlist.h> 23#include <linux/seq_file.h> 24#include <linux/slab.h> 25#include <linux/string.h> 26 27#include "internal.h" 28#include "scatterwalk.h" 29 30enum { 31 BLKCIPHER_WALK_PHYS = 1 << 0, 32 BLKCIPHER_WALK_SLOW = 1 << 1, 33 BLKCIPHER_WALK_COPY = 1 << 2, 34 BLKCIPHER_WALK_DIFF = 1 << 3, 35}; 36 37static int blkcipher_walk_next(struct blkcipher_desc *desc, 38 struct blkcipher_walk *walk); 39static int blkcipher_walk_first(struct blkcipher_desc *desc, 40 struct blkcipher_walk *walk); 41 42static inline void blkcipher_map_src(struct blkcipher_walk *walk) 43{ 44 walk->src.virt.addr = scatterwalk_map(&walk->in, 0); 45} 46 47static inline void blkcipher_map_dst(struct blkcipher_walk *walk) 48{ 49 walk->dst.virt.addr = scatterwalk_map(&walk->out, 1); 50} 51 52static inline void blkcipher_unmap_src(struct blkcipher_walk *walk) 53{ 54 scatterwalk_unmap(walk->src.virt.addr, 0); 55} 56 57static inline void blkcipher_unmap_dst(struct blkcipher_walk *walk) 58{ 59 scatterwalk_unmap(walk->dst.virt.addr, 1); 60} 61 62static inline u8 *blkcipher_get_spot(u8 *start, unsigned int len) 63{ 64 if (offset_in_page(start + len) < len) 65 return (u8 *)((unsigned long)(start + len) & PAGE_MASK); 66 return start; 67} 68 69static inline unsigned int blkcipher_done_slow(struct crypto_blkcipher *tfm, 70 struct blkcipher_walk *walk, 71 unsigned int bsize) 72{ 73 u8 *addr; 74 unsigned int alignmask = crypto_blkcipher_alignmask(tfm); 75 76 addr = (u8 *)ALIGN((unsigned long)walk->buffer, alignmask + 1); 77 addr = blkcipher_get_spot(addr, bsize); 78 scatterwalk_copychunks(addr, &walk->out, bsize, 1); 79 return bsize; 80} 81 82static inline unsigned int blkcipher_done_fast(struct blkcipher_walk *walk, 83 unsigned int n) 84{ 85 n = walk->nbytes - n; 86 87 if (walk->flags & BLKCIPHER_WALK_COPY) { 88 blkcipher_map_dst(walk); 89 memcpy(walk->dst.virt.addr, walk->page, n); 90 blkcipher_unmap_dst(walk); 91 } else if (!(walk->flags & BLKCIPHER_WALK_PHYS)) { 92 blkcipher_unmap_src(walk); 93 if (walk->flags & BLKCIPHER_WALK_DIFF) 94 blkcipher_unmap_dst(walk); 95 } 96 97 scatterwalk_advance(&walk->in, n); 98 scatterwalk_advance(&walk->out, n); 99 100 return n; 101} 102 103int blkcipher_walk_done(struct blkcipher_desc *desc, 104 struct blkcipher_walk *walk, int err) 105{ 106 struct crypto_blkcipher *tfm = desc->tfm; 107 unsigned int nbytes = 0; 108 109 if (likely(err >= 0)) { 110 unsigned int bsize = crypto_blkcipher_blocksize(tfm); 111 unsigned int n; 112 113 if (likely(!(walk->flags & BLKCIPHER_WALK_SLOW))) 114 n = blkcipher_done_fast(walk, err); 115 else 116 n = blkcipher_done_slow(tfm, walk, bsize); 117 118 nbytes = walk->total - n; 119 err = 0; 120 } 121 122 scatterwalk_done(&walk->in, 0, nbytes); 123 scatterwalk_done(&walk->out, 1, nbytes); 124 125 walk->total = nbytes; 126 walk->nbytes = nbytes; 127 128 if (nbytes) { 129 crypto_yield(desc->flags); 130 return blkcipher_walk_next(desc, walk); 131 } 132 133 if (walk->iv != desc->info) 134 memcpy(desc->info, walk->iv, crypto_blkcipher_ivsize(tfm)); 135 if (walk->buffer != walk->page) 136 kfree(walk->buffer); 137 if (walk->page) 138 free_page((unsigned long)walk->page); 139 140 return err; 141} 142EXPORT_SYMBOL_GPL(blkcipher_walk_done); 143 144static inline int blkcipher_next_slow(struct blkcipher_desc *desc, 145 struct blkcipher_walk *walk, 146 unsigned int bsize, 147 unsigned int alignmask) 148{ 149 unsigned int n; 150 151 if (walk->buffer) 152 goto ok; 153 154 walk->buffer = walk->page; 155 if (walk->buffer) 156 goto ok; 157 158 n = bsize * 2 + (alignmask & ~(crypto_tfm_ctx_alignment() - 1)); 159 walk->buffer = kmalloc(n, GFP_ATOMIC); 160 if (!walk->buffer) 161 return blkcipher_walk_done(desc, walk, -ENOMEM); 162 163ok: 164 walk->dst.virt.addr = (u8 *)ALIGN((unsigned long)walk->buffer, 165 alignmask + 1); 166 walk->dst.virt.addr = blkcipher_get_spot(walk->dst.virt.addr, bsize); 167 walk->src.virt.addr = blkcipher_get_spot(walk->dst.virt.addr + bsize, 168 bsize); 169 170 scatterwalk_copychunks(walk->src.virt.addr, &walk->in, bsize, 0); 171 172 walk->nbytes = bsize; 173 walk->flags |= BLKCIPHER_WALK_SLOW; 174 175 return 0; 176} 177 178static inline int blkcipher_next_copy(struct blkcipher_walk *walk) 179{ 180 u8 *tmp = walk->page; 181 182 blkcipher_map_src(walk); 183 memcpy(tmp, walk->src.virt.addr, walk->nbytes); 184 blkcipher_unmap_src(walk); 185 186 walk->src.virt.addr = tmp; 187 walk->dst.virt.addr = tmp; 188 189 return 0; 190} 191 192static inline int blkcipher_next_fast(struct blkcipher_desc *desc, 193 struct blkcipher_walk *walk) 194{ 195 unsigned long diff; 196 197 walk->src.phys.page = scatterwalk_page(&walk->in); 198 walk->src.phys.offset = offset_in_page(walk->in.offset); 199 walk->dst.phys.page = scatterwalk_page(&walk->out); 200 walk->dst.phys.offset = offset_in_page(walk->out.offset); 201 202 if (walk->flags & BLKCIPHER_WALK_PHYS) 203 return 0; 204 205 diff = walk->src.phys.offset - walk->dst.phys.offset; 206 diff |= walk->src.virt.page - walk->dst.virt.page; 207 208 blkcipher_map_src(walk); 209 walk->dst.virt.addr = walk->src.virt.addr; 210 211 if (diff) { 212 walk->flags |= BLKCIPHER_WALK_DIFF; 213 blkcipher_map_dst(walk); 214 } 215 216 return 0; 217} 218 219static int blkcipher_walk_next(struct blkcipher_desc *desc, 220 struct blkcipher_walk *walk) 221{ 222 struct crypto_blkcipher *tfm = desc->tfm; 223 unsigned int alignmask = crypto_blkcipher_alignmask(tfm); 224 unsigned int bsize = crypto_blkcipher_blocksize(tfm); 225 unsigned int n; 226 int err; 227 228 n = walk->total; 229 if (unlikely(n < bsize)) { 230 desc->flags |= CRYPTO_TFM_RES_BAD_BLOCK_LEN; 231 return blkcipher_walk_done(desc, walk, -EINVAL); 232 } 233 234 walk->flags &= ~(BLKCIPHER_WALK_SLOW | BLKCIPHER_WALK_COPY | 235 BLKCIPHER_WALK_DIFF); 236 if (!scatterwalk_aligned(&walk->in, alignmask) || 237 !scatterwalk_aligned(&walk->out, alignmask)) { 238 walk->flags |= BLKCIPHER_WALK_COPY; 239 if (!walk->page) { 240 walk->page = (void *)__get_free_page(GFP_ATOMIC); 241 if (!walk->page) 242 n = 0; 243 } 244 } 245 246 n = scatterwalk_clamp(&walk->in, n); 247 n = scatterwalk_clamp(&walk->out, n); 248 249 if (unlikely(n < bsize)) { 250 err = blkcipher_next_slow(desc, walk, bsize, alignmask); 251 goto set_phys_lowmem; 252 } 253 254 walk->nbytes = n; 255 if (walk->flags & BLKCIPHER_WALK_COPY) { 256 err = blkcipher_next_copy(walk); 257 goto set_phys_lowmem; 258 } 259 260 return blkcipher_next_fast(desc, walk); 261 262set_phys_lowmem: 263 if (walk->flags & BLKCIPHER_WALK_PHYS) { 264 walk->src.phys.page = virt_to_page(walk->src.virt.addr); 265 walk->dst.phys.page = virt_to_page(walk->dst.virt.addr); 266 walk->src.phys.offset &= PAGE_SIZE - 1; 267 walk->dst.phys.offset &= PAGE_SIZE - 1; 268 } 269 return err; 270} 271 272static inline int blkcipher_copy_iv(struct blkcipher_walk *walk, 273 struct crypto_blkcipher *tfm, 274 unsigned int alignmask) 275{ 276 unsigned bs = crypto_blkcipher_blocksize(tfm); 277 unsigned int ivsize = crypto_blkcipher_ivsize(tfm); 278 unsigned int size = bs * 2 + ivsize + max(bs, ivsize) - (alignmask + 1); 279 u8 *iv; 280 281 size += alignmask & ~(crypto_tfm_ctx_alignment() - 1); 282 walk->buffer = kmalloc(size, GFP_ATOMIC); 283 if (!walk->buffer) 284 return -ENOMEM; 285 286 iv = (u8 *)ALIGN((unsigned long)walk->buffer, alignmask + 1); 287 iv = blkcipher_get_spot(iv, bs) + bs; 288 iv = blkcipher_get_spot(iv, bs) + bs; 289 iv = blkcipher_get_spot(iv, ivsize); 290 291 walk->iv = memcpy(iv, walk->iv, ivsize); 292 return 0; 293} 294 295int blkcipher_walk_virt(struct blkcipher_desc *desc, 296 struct blkcipher_walk *walk) 297{ 298 walk->flags &= ~BLKCIPHER_WALK_PHYS; 299 return blkcipher_walk_first(desc, walk); 300} 301EXPORT_SYMBOL_GPL(blkcipher_walk_virt); 302 303int blkcipher_walk_phys(struct blkcipher_desc *desc, 304 struct blkcipher_walk *walk) 305{ 306 walk->flags |= BLKCIPHER_WALK_PHYS; 307 return blkcipher_walk_first(desc, walk); 308} 309EXPORT_SYMBOL_GPL(blkcipher_walk_phys); 310 311static int blkcipher_walk_first(struct blkcipher_desc *desc, 312 struct blkcipher_walk *walk) 313{ 314 struct crypto_blkcipher *tfm = desc->tfm; 315 unsigned int alignmask = crypto_blkcipher_alignmask(tfm); 316 317 if (WARN_ON_ONCE(in_irq())) 318 return -EDEADLK; 319 320 walk->nbytes = walk->total; 321 if (unlikely(!walk->total)) 322 return 0; 323 324 walk->buffer = NULL; 325 walk->iv = desc->info; 326 if (unlikely(((unsigned long)walk->iv & alignmask))) { 327 int err = blkcipher_copy_iv(walk, tfm, alignmask); 328 if (err) 329 return err; 330 } 331 332 scatterwalk_start(&walk->in, walk->in.sg); 333 scatterwalk_start(&walk->out, walk->out.sg); 334 walk->page = NULL; 335 336 return blkcipher_walk_next(desc, walk); 337} 338 339static int setkey(struct crypto_tfm *tfm, const u8 *key, 340 unsigned int keylen) 341{ 342 struct blkcipher_alg *cipher = &tfm->__crt_alg->cra_blkcipher; 343 344 if (keylen < cipher->min_keysize || keylen > cipher->max_keysize) { 345 tfm->crt_flags |= CRYPTO_TFM_RES_BAD_KEY_LEN; 346 return -EINVAL; 347 } 348 349 return cipher->setkey(tfm, key, keylen); 350} 351 352static int async_setkey(struct crypto_ablkcipher *tfm, const u8 *key, 353 unsigned int keylen) 354{ 355 return setkey(crypto_ablkcipher_tfm(tfm), key, keylen); 356} 357 358static int async_encrypt(struct ablkcipher_request *req) 359{ 360 struct crypto_tfm *tfm = req->base.tfm; 361 struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher; 362 struct blkcipher_desc desc = { 363 .tfm = __crypto_blkcipher_cast(tfm), 364 .info = req->info, 365 .flags = req->base.flags, 366 }; 367 368 369 return alg->encrypt(&desc, req->dst, req->src, req->nbytes); 370} 371 372static int async_decrypt(struct ablkcipher_request *req) 373{ 374 struct crypto_tfm *tfm = req->base.tfm; 375 struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher; 376 struct blkcipher_desc desc = { 377 .tfm = __crypto_blkcipher_cast(tfm), 378 .info = req->info, 379 .flags = req->base.flags, 380 }; 381 382 return alg->decrypt(&desc, req->dst, req->src, req->nbytes); 383} 384 385static unsigned int crypto_blkcipher_ctxsize(struct crypto_alg *alg, u32 type, 386 u32 mask) 387{ 388 struct blkcipher_alg *cipher = &alg->cra_blkcipher; 389 unsigned int len = alg->cra_ctxsize; 390 391 type ^= CRYPTO_ALG_ASYNC; 392 mask &= CRYPTO_ALG_ASYNC; 393 if ((type & mask) && cipher->ivsize) { 394 len = ALIGN(len, (unsigned long)alg->cra_alignmask + 1); 395 len += cipher->ivsize; 396 } 397 398 return len; 399} 400 401static int crypto_init_blkcipher_ops_async(struct crypto_tfm *tfm) 402{ 403 struct ablkcipher_tfm *crt = &tfm->crt_ablkcipher; 404 struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher; 405 406 crt->setkey = async_setkey; 407 crt->encrypt = async_encrypt; 408 crt->decrypt = async_decrypt; 409 crt->ivsize = alg->ivsize; 410 411 return 0; 412} 413 414static int crypto_init_blkcipher_ops_sync(struct crypto_tfm *tfm) 415{ 416 struct blkcipher_tfm *crt = &tfm->crt_blkcipher; 417 struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher; 418 unsigned long align = crypto_tfm_alg_alignmask(tfm) + 1; 419 unsigned long addr; 420 421 crt->setkey = setkey; 422 crt->encrypt = alg->encrypt; 423 crt->decrypt = alg->decrypt; 424 425 addr = (unsigned long)crypto_tfm_ctx(tfm); 426 addr = ALIGN(addr, align); 427 addr += ALIGN(tfm->__crt_alg->cra_ctxsize, align); 428 crt->iv = (void *)addr; 429 430 return 0; 431} 432 433static int crypto_init_blkcipher_ops(struct crypto_tfm *tfm, u32 type, u32 mask) 434{ 435 struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher; 436 437 if (alg->ivsize > PAGE_SIZE / 8) 438 return -EINVAL; 439 440 type ^= CRYPTO_ALG_ASYNC; 441 mask &= CRYPTO_ALG_ASYNC; 442 if (type & mask) 443 return crypto_init_blkcipher_ops_sync(tfm); 444 else 445 return crypto_init_blkcipher_ops_async(tfm); 446} 447 448static void crypto_blkcipher_show(struct seq_file *m, struct crypto_alg *alg) 449 __attribute__ ((unused)); 450static void crypto_blkcipher_show(struct seq_file *m, struct crypto_alg *alg) 451{ 452 seq_printf(m, "type : blkcipher\n"); 453 seq_printf(m, "blocksize : %u\n", alg->cra_blocksize); 454 seq_printf(m, "min keysize : %u\n", alg->cra_blkcipher.min_keysize); 455 seq_printf(m, "max keysize : %u\n", alg->cra_blkcipher.max_keysize); 456 seq_printf(m, "ivsize : %u\n", alg->cra_blkcipher.ivsize); 457} 458 459const struct crypto_type crypto_blkcipher_type = { 460 .ctxsize = crypto_blkcipher_ctxsize, 461 .init = crypto_init_blkcipher_ops, 462#ifdef CONFIG_PROC_FS 463 .show = crypto_blkcipher_show, 464#endif 465}; 466EXPORT_SYMBOL_GPL(crypto_blkcipher_type); 467 468MODULE_LICENSE("GPL"); 469MODULE_DESCRIPTION("Generic block chaining cipher type"); 470