crypto/ablkcipher.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Asynchronous block chaining cipher operations.
   4  *
   5  * This is the asynchronous version of blkcipher.c indicating completion
   6  * via a callback.
   7  *
   8  * Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au>
   9  */
  10
  11 #include <crypto/internal/skcipher.h>
  12 #include <linux/err.h>
  13 #include <linux/kernel.h>
  14 #include <linux/slab.h>
  15 #include <linux/seq_file.h>
  16 #include <linux/cryptouser.h>
  17 #include <linux/compiler.h>
  18 #include <net/netlink.h>
  19
  20 #include <crypto/scatterwalk.h>
  21
  22 #include "internal.h"
  23
  24 struct ablkcipher_buffer {
  25         struct list_head        entry;
  26         struct scatter_walk     dst;
  27         unsigned int            len;
  28         void                    *data;
  29 };
  30
  31 enum {
  32         ABLKCIPHER_WALK_SLOW = 1 << 0,
  33 };
  34
  35 static inline void ablkcipher_buffer_write(struct ablkcipher_buffer *p)
  36 {
  37         scatterwalk_copychunks(p->data, &p->dst, p->len, 1);
  38 }
  39
  40 void __ablkcipher_walk_complete(struct ablkcipher_walk *walk)
  41 {
  42         struct ablkcipher_buffer *p, *tmp;
  43
  44         list_for_each_entry_safe(p, tmp, &walk->buffers, entry) {
  45                 ablkcipher_buffer_write(p);
  46                 list_del(&p->entry);
  47                 kfree(p);
  48         }
  49 }
  50 EXPORT_SYMBOL_GPL(__ablkcipher_walk_complete);
  51
  52 static inline void ablkcipher_queue_write(struct ablkcipher_walk *walk,
  53                                           struct ablkcipher_buffer *p)
  54 {
  55         p->dst = walk->out;
  56         list_add_tail(&p->entry, &walk->buffers);
  57 }
  58
  59 /* Get a spot of the specified length that does not straddle a page.
  60  * The caller needs to ensure that there is enough space for this operation.
  61  */
  62 static inline u8 *ablkcipher_get_spot(u8 *start, unsigned int len)
  63 {
  64         u8 *end_page = (u8 *)(((unsigned long)(start + len - 1)) & PAGE_MASK);
  65
  66         return max(start, end_page);
  67 }
  68
  69 static inline void ablkcipher_done_slow(struct ablkcipher_walk *walk,
  70                                         unsigned int n)
  71 {
  72         for (;;) {
  73                 unsigned int len_this_page = scatterwalk_pagelen(&walk->out);
  74
  75                 if (len_this_page > n)
  76                         len_this_page = n;
  77                 scatterwalk_advance(&walk->out, n);
  78                 if (n == len_this_page)
  79                         break;
  80                 n -= len_this_page;
  81                 scatterwalk_start(&walk->out, sg_next(walk->out.sg));
  82         }
  83 }
  84
  85 static inline void ablkcipher_done_fast(struct ablkcipher_walk *walk,
  86                                         unsigned int n)
  87 {
  88         scatterwalk_advance(&walk->in, n);
  89         scatterwalk_advance(&walk->out, n);
  90 }
  91
  92 static int ablkcipher_walk_next(struct ablkcipher_request *req,
  93                                 struct ablkcipher_walk *walk);
  94
  95 int ablkcipher_walk_done(struct ablkcipher_request *req,
  96                          struct ablkcipher_walk *walk, int err)
  97 {
  98         struct crypto_tfm *tfm = req->base.tfm;
  99         unsigned int n; /* bytes processed */
 100         bool more;
 101
 102         if (unlikely(err < 0))
 103                 goto finish;
 104
 105         n = walk->nbytes - err;
 106         walk->total -= n;
 107         more = (walk->total != 0);
 108
 109         if (likely(!(walk->flags & ABLKCIPHER_WALK_SLOW))) {
 110                 ablkcipher_done_fast(walk, n);
 111         } else {
 112                 if (WARN_ON(err)) {
 113                         /* unexpected case; didn't process all bytes */
 114                         err = -EINVAL;
 115                         goto finish;
 116                 }
 117                 ablkcipher_done_slow(walk, n);
 118         }
 119
 120         scatterwalk_done(&walk->in, 0, more);
 121         scatterwalk_done(&walk->out, 1, more);
 122
 123         if (more) {
 124                 crypto_yield(req->base.flags);
 125                 return ablkcipher_walk_next(req, walk);
 126         }
 127         err = 0;
 128 finish:
 129         walk->nbytes = 0;
 130         if (walk->iv != req->info)
 131                 memcpy(req->info, walk->iv, tfm->crt_ablkcipher.ivsize);
 132         kfree(walk->iv_buffer);
 133         return err;
 134 }
 135 EXPORT_SYMBOL_GPL(ablkcipher_walk_done);
 136
 137 static inline int ablkcipher_next_slow(struct ablkcipher_request *req,
 138                                        struct ablkcipher_walk *walk,
 139                                        unsigned int bsize,
 140                                        unsigned int alignmask,
 141                                        void **src_p, void **dst_p)
 142 {
 143         unsigned aligned_bsize = ALIGN(bsize, alignmask + 1);
 144         struct ablkcipher_buffer *p;
 145         void *src, *dst, *base;
 146         unsigned int n;
 147
 148         n = ALIGN(sizeof(struct ablkcipher_buffer), alignmask + 1);
 149         n += (aligned_bsize * 3 - (alignmask + 1) +
 150               (alignmask & ~(crypto_tfm_ctx_alignment() - 1)));
 151
 152         p = kmalloc(n, GFP_ATOMIC);
 153         if (!p)
 154                 return ablkcipher_walk_done(req, walk, -ENOMEM);
 155
 156         base = p + 1;
 157
 158         dst = (u8 *)ALIGN((unsigned long)base, alignmask + 1);
 159         src = dst = ablkcipher_get_spot(dst, bsize);
 160
 161         p->len = bsize;
 162         p->data = dst;
 163
 164         scatterwalk_copychunks(src, &walk->in, bsize, 0);
 165
 166         ablkcipher_queue_write(walk, p);
 167
 168         walk->nbytes = bsize;
 169         walk->flags |= ABLKCIPHER_WALK_SLOW;
 170
 171         *src_p = src;
 172         *dst_p = dst;
 173
 174         return 0;
 175 }
 176
 177 static inline int ablkcipher_copy_iv(struct ablkcipher_walk *walk,
 178                                      struct crypto_tfm *tfm,
 179                                      unsigned int alignmask)
 180 {
 181         unsigned bs = walk->blocksize;
 182         unsigned int ivsize = tfm->crt_ablkcipher.ivsize;
 183         unsigned aligned_bs = ALIGN(bs, alignmask + 1);
 184         unsigned int size = aligned_bs * 2 + ivsize + max(aligned_bs, ivsize) -
 185                             (alignmask + 1);
 186         u8 *iv;
 187
 188         size += alignmask & ~(crypto_tfm_ctx_alignment() - 1);
 189         walk->iv_buffer = kmalloc(size, GFP_ATOMIC);
 190         if (!walk->iv_buffer)
 191                 return -ENOMEM;
 192
 193         iv = (u8 *)ALIGN((unsigned long)walk->iv_buffer, alignmask + 1);
 194         iv = ablkcipher_get_spot(iv, bs) + aligned_bs;
 195         iv = ablkcipher_get_spot(iv, bs) + aligned_bs;
 196         iv = ablkcipher_get_spot(iv, ivsize);
 197
 198         walk->iv = memcpy(iv, walk->iv, ivsize);
 199         return 0;
 200 }
 201
 202 static inline int ablkcipher_next_fast(struct ablkcipher_request *req,
 203                                        struct ablkcipher_walk *walk)
 204 {
 205         walk->src.page = scatterwalk_page(&walk->in);
 206         walk->src.offset = offset_in_page(walk->in.offset);
 207         walk->dst.page = scatterwalk_page(&walk->out);
 208         walk->dst.offset = offset_in_page(walk->out.offset);
 209
 210         return 0;
 211 }
 212
 213 static int ablkcipher_walk_next(struct ablkcipher_request *req,
 214                                 struct ablkcipher_walk *walk)
 215 {
 216         struct crypto_tfm *tfm = req->base.tfm;
 217         unsigned int alignmask, bsize, n;
 218         void *src, *dst;
 219         int err;
 220
 221         alignmask = crypto_tfm_alg_alignmask(tfm);
 222         n = walk->total;
 223         if (unlikely(n < crypto_tfm_alg_blocksize(tfm))) {
 224                 req->base.flags |= CRYPTO_TFM_RES_BAD_BLOCK_LEN;
 225                 return ablkcipher_walk_done(req, walk, -EINVAL);
 226         }
 227
 228         walk->flags &= ~ABLKCIPHER_WALK_SLOW;
 229         src = dst = NULL;
 230
 231         bsize = min(walk->blocksize, n);
 232         n = scatterwalk_clamp(&walk->in, n);
 233         n = scatterwalk_clamp(&walk->out, n);
 234
 235         if (n < bsize ||
 236             !scatterwalk_aligned(&walk->in, alignmask) ||
 237             !scatterwalk_aligned(&walk->out, alignmask)) {
 238                 err = ablkcipher_next_slow(req, walk, bsize, alignmask,
 239                                            &src, &dst);
 240                 goto set_phys_lowmem;
 241         }
 242
 243         walk->nbytes = n;
 244
 245         return ablkcipher_next_fast(req, walk);
 246
 247 set_phys_lowmem:
 248         if (err >= 0) {
 249                 walk->src.page = virt_to_page(src);
 250                 walk->dst.page = virt_to_page(dst);
 251                 walk->src.offset = ((unsigned long)src & (PAGE_SIZE - 1));
 252                 walk->dst.offset = ((unsigned long)dst & (PAGE_SIZE - 1));
 253         }
 254
 255         return err;
 256 }
 257
 258 static int ablkcipher_walk_first(struct ablkcipher_request *req,
 259                                  struct ablkcipher_walk *walk)
 260 {
 261         struct crypto_tfm *tfm = req->base.tfm;
 262         unsigned int alignmask;
 263
 264         alignmask = crypto_tfm_alg_alignmask(tfm);
 265         if (WARN_ON_ONCE(in_irq()))
 266                 return -EDEADLK;
 267
 268         walk->iv = req->info;
 269         walk->nbytes = walk->total;
 270         if (unlikely(!walk->total))
 271                 return 0;
 272
 273         walk->iv_buffer = NULL;
 274         if (unlikely(((unsigned long)walk->iv & alignmask))) {
 275                 int err = ablkcipher_copy_iv(walk, tfm, alignmask);
 276
 277                 if (err)
 278                         return err;
 279         }
 280
 281         scatterwalk_start(&walk->in, walk->in.sg);
 282         scatterwalk_start(&walk->out, walk->out.sg);
 283
 284         return ablkcipher_walk_next(req, walk);
 285 }
 286
 287 int ablkcipher_walk_phys(struct ablkcipher_request *req,
 288                          struct ablkcipher_walk *walk)
 289 {
 290         walk->blocksize = crypto_tfm_alg_blocksize(req->base.tfm);
 291         return ablkcipher_walk_first(req, walk);
 292 }
 293 EXPORT_SYMBOL_GPL(ablkcipher_walk_phys);
 294
 295 static int setkey_unaligned(struct crypto_ablkcipher *tfm, const u8 *key,
 296                             unsigned int keylen)
 297 {
 298         struct ablkcipher_alg *cipher = crypto_ablkcipher_alg(tfm);
 299         unsigned long alignmask = crypto_ablkcipher_alignmask(tfm);
 300         int ret;
 301         u8 *buffer, *alignbuffer;
 302         unsigned long absize;
 303
 304         absize = keylen + alignmask;
 305         buffer = kmalloc(absize, GFP_ATOMIC);
 306         if (!buffer)
 307                 return -ENOMEM;
 308
 309         alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
 310         memcpy(alignbuffer, key, keylen);
 311         ret = cipher->setkey(tfm, alignbuffer, keylen);
 312         memset(alignbuffer, 0, keylen);
 313         kfree(buffer);
 314         return ret;
 315 }
 316
 317 static int setkey(struct crypto_ablkcipher *tfm, const u8 *key,
 318                   unsigned int keylen)
 319 {
 320         struct ablkcipher_alg *cipher = crypto_ablkcipher_alg(tfm);
 321         unsigned long alignmask = crypto_ablkcipher_alignmask(tfm);
 322
 323         if (keylen < cipher->min_keysize || keylen > cipher->max_keysize) {
 324                 crypto_ablkcipher_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
 325                 return -EINVAL;
 326         }
 327
 328         if ((unsigned long)key & alignmask)
 329                 return setkey_unaligned(tfm, key, keylen);
 330
 331         return cipher->setkey(tfm, key, keylen);
 332 }
 333
 334 static unsigned int crypto_ablkcipher_ctxsize(struct crypto_alg *alg, u32 type,
 335                                               u32 mask)
 336 {
 337         return alg->cra_ctxsize;
 338 }
 339
 340 static int crypto_init_ablkcipher_ops(struct crypto_tfm *tfm, u32 type,
 341                                       u32 mask)
 342 {
 343         struct ablkcipher_alg *alg = &tfm->__crt_alg->cra_ablkcipher;
 344         struct ablkcipher_tfm *crt = &tfm->crt_ablkcipher;
 345
 346         if (alg->ivsize > PAGE_SIZE / 8)
 347                 return -EINVAL;
 348
 349         crt->setkey = setkey;
 350         crt->encrypt = alg->encrypt;
 351         crt->decrypt = alg->decrypt;
 352         crt->base = __crypto_ablkcipher_cast(tfm);
 353         crt->ivsize = alg->ivsize;
 354
 355         return 0;
 356 }
 357
 358 #ifdef CONFIG_NET
 359 static int crypto_ablkcipher_report(struct sk_buff *skb, struct crypto_alg *alg)
 360 {
 361         struct crypto_report_blkcipher rblkcipher;
 362
 363         memset(&rblkcipher, 0, sizeof(rblkcipher));
 364
 365         strscpy(rblkcipher.type, "ablkcipher", sizeof(rblkcipher.type));
 366         strscpy(rblkcipher.geniv, "<default>", sizeof(rblkcipher.geniv));
 367
 368         rblkcipher.blocksize = alg->cra_blocksize;
 369         rblkcipher.min_keysize = alg->cra_ablkcipher.min_keysize;
 370         rblkcipher.max_keysize = alg->cra_ablkcipher.max_keysize;
 371         rblkcipher.ivsize = alg->cra_ablkcipher.ivsize;
 372
 373         return nla_put(skb, CRYPTOCFGA_REPORT_BLKCIPHER,
 374                        sizeof(rblkcipher), &rblkcipher);
 375 }
 376 #else
 377 static int crypto_ablkcipher_report(struct sk_buff *skb, struct crypto_alg *alg)
 378 {
 379         return -ENOSYS;
 380 }
 381 #endif
 382
 383 static void crypto_ablkcipher_show(struct seq_file *m, struct crypto_alg *alg)
 384         __maybe_unused;
 385 static void crypto_ablkcipher_show(struct seq_file *m, struct crypto_alg *alg)
 386 {
 387         struct ablkcipher_alg *ablkcipher = &alg->cra_ablkcipher;
 388
 389         seq_printf(m, "type         : ablkcipher\n");
 390         seq_printf(m, "async        : %s\n", alg->cra_flags & CRYPTO_ALG_ASYNC ?
 391                                              "yes" : "no");
 392         seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
 393         seq_printf(m, "min keysize  : %u\n", ablkcipher->min_keysize);
 394         seq_printf(m, "max keysize  : %u\n", ablkcipher->max_keysize);
 395         seq_printf(m, "ivsize       : %u\n", ablkcipher->ivsize);
 396         seq_printf(m, "geniv        : <default>\n");
 397 }
 398
 399 const struct crypto_type crypto_ablkcipher_type = {
 400         .ctxsize = crypto_ablkcipher_ctxsize,
 401         .init = crypto_init_ablkcipher_ops,
 402 #ifdef CONFIG_PROC_FS
 403         .show = crypto_ablkcipher_show,
 404 #endif
 405         .report = crypto_ablkcipher_report,
 406 };
 407 EXPORT_SYMBOL_GPL(crypto_ablkcipher_type);