[IA64] Kexec/Kdump: honour non-zero crashkernel offset.
[linux-2.6/mini2440.git] / crypto / blkcipher.c
blob034c939bf91a2a26cabcbc836f508bbf283e911f
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.
8 * Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au>
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.
17 #include <linux/crypto.h>
18 #include <linux/errno.h>
19 #include <linux/kernel.h>
20 #include <linux/io.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>
27 #include "internal.h"
28 #include "scatterwalk.h"
30 enum {
31 BLKCIPHER_WALK_PHYS = 1 << 0,
32 BLKCIPHER_WALK_SLOW = 1 << 1,
33 BLKCIPHER_WALK_COPY = 1 << 2,
34 BLKCIPHER_WALK_DIFF = 1 << 3,
37 static int blkcipher_walk_next(struct blkcipher_desc *desc,
38 struct blkcipher_walk *walk);
39 static int blkcipher_walk_first(struct blkcipher_desc *desc,
40 struct blkcipher_walk *walk);
42 static inline void blkcipher_map_src(struct blkcipher_walk *walk)
44 walk->src.virt.addr = scatterwalk_map(&walk->in, 0);
47 static inline void blkcipher_map_dst(struct blkcipher_walk *walk)
49 walk->dst.virt.addr = scatterwalk_map(&walk->out, 1);
52 static inline void blkcipher_unmap_src(struct blkcipher_walk *walk)
54 scatterwalk_unmap(walk->src.virt.addr, 0);
57 static inline void blkcipher_unmap_dst(struct blkcipher_walk *walk)
59 scatterwalk_unmap(walk->dst.virt.addr, 1);
62 static inline u8 *blkcipher_get_spot(u8 *start, unsigned int len)
64 if (offset_in_page(start + len) < len)
65 return (u8 *)((unsigned long)(start + len) & PAGE_MASK);
66 return start;
69 static inline unsigned int blkcipher_done_slow(struct crypto_blkcipher *tfm,
70 struct blkcipher_walk *walk,
71 unsigned int bsize)
73 u8 *addr;
74 unsigned int alignmask = crypto_blkcipher_alignmask(tfm);
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;
82 static inline unsigned int blkcipher_done_fast(struct blkcipher_walk *walk,
83 unsigned int n)
85 n = walk->nbytes - n;
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);
97 scatterwalk_advance(&walk->in, n);
98 scatterwalk_advance(&walk->out, n);
100 return n;
103 int blkcipher_walk_done(struct blkcipher_desc *desc,
104 struct blkcipher_walk *walk, int err)
106 struct crypto_blkcipher *tfm = desc->tfm;
107 unsigned int nbytes = 0;
109 if (likely(err >= 0)) {
110 unsigned int bsize = crypto_blkcipher_blocksize(tfm);
111 unsigned int n;
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);
118 nbytes = walk->total - n;
119 err = 0;
122 scatterwalk_done(&walk->in, 0, nbytes);
123 scatterwalk_done(&walk->out, 1, nbytes);
125 walk->total = nbytes;
126 walk->nbytes = nbytes;
128 if (nbytes) {
129 crypto_yield(desc->flags);
130 return blkcipher_walk_next(desc, walk);
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);
140 return err;
142 EXPORT_SYMBOL_GPL(blkcipher_walk_done);
144 static inline int blkcipher_next_slow(struct blkcipher_desc *desc,
145 struct blkcipher_walk *walk,
146 unsigned int bsize,
147 unsigned int alignmask)
149 unsigned int n;
151 if (walk->buffer)
152 goto ok;
154 walk->buffer = walk->page;
155 if (walk->buffer)
156 goto ok;
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);
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);
170 scatterwalk_copychunks(walk->src.virt.addr, &walk->in, bsize, 0);
172 walk->nbytes = bsize;
173 walk->flags |= BLKCIPHER_WALK_SLOW;
175 return 0;
178 static inline int blkcipher_next_copy(struct blkcipher_walk *walk)
180 u8 *tmp = walk->page;
182 blkcipher_map_src(walk);
183 memcpy(tmp, walk->src.virt.addr, walk->nbytes);
184 blkcipher_unmap_src(walk);
186 walk->src.virt.addr = tmp;
187 walk->dst.virt.addr = tmp;
189 return 0;
192 static inline int blkcipher_next_fast(struct blkcipher_desc *desc,
193 struct blkcipher_walk *walk)
195 unsigned long diff;
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);
202 if (walk->flags & BLKCIPHER_WALK_PHYS)
203 return 0;
205 diff = walk->src.phys.offset - walk->dst.phys.offset;
206 diff |= walk->src.virt.page - walk->dst.virt.page;
208 blkcipher_map_src(walk);
209 walk->dst.virt.addr = walk->src.virt.addr;
211 if (diff) {
212 walk->flags |= BLKCIPHER_WALK_DIFF;
213 blkcipher_map_dst(walk);
216 return 0;
219 static int blkcipher_walk_next(struct blkcipher_desc *desc,
220 struct blkcipher_walk *walk)
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;
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);
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;
246 n = scatterwalk_clamp(&walk->in, n);
247 n = scatterwalk_clamp(&walk->out, n);
249 if (unlikely(n < bsize)) {
250 err = blkcipher_next_slow(desc, walk, bsize, alignmask);
251 goto set_phys_lowmem;
254 walk->nbytes = n;
255 if (walk->flags & BLKCIPHER_WALK_COPY) {
256 err = blkcipher_next_copy(walk);
257 goto set_phys_lowmem;
260 return blkcipher_next_fast(desc, walk);
262 set_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;
269 return err;
272 static inline int blkcipher_copy_iv(struct blkcipher_walk *walk,
273 struct crypto_blkcipher *tfm,
274 unsigned int alignmask)
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;
281 size += alignmask & ~(crypto_tfm_ctx_alignment() - 1);
282 walk->buffer = kmalloc(size, GFP_ATOMIC);
283 if (!walk->buffer)
284 return -ENOMEM;
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);
291 walk->iv = memcpy(iv, walk->iv, ivsize);
292 return 0;
295 int blkcipher_walk_virt(struct blkcipher_desc *desc,
296 struct blkcipher_walk *walk)
298 walk->flags &= ~BLKCIPHER_WALK_PHYS;
299 return blkcipher_walk_first(desc, walk);
301 EXPORT_SYMBOL_GPL(blkcipher_walk_virt);
303 int blkcipher_walk_phys(struct blkcipher_desc *desc,
304 struct blkcipher_walk *walk)
306 walk->flags |= BLKCIPHER_WALK_PHYS;
307 return blkcipher_walk_first(desc, walk);
309 EXPORT_SYMBOL_GPL(blkcipher_walk_phys);
311 static int blkcipher_walk_first(struct blkcipher_desc *desc,
312 struct blkcipher_walk *walk)
314 struct crypto_blkcipher *tfm = desc->tfm;
315 unsigned int alignmask = crypto_blkcipher_alignmask(tfm);
317 walk->nbytes = walk->total;
318 if (unlikely(!walk->total))
319 return 0;
321 walk->buffer = NULL;
322 walk->iv = desc->info;
323 if (unlikely(((unsigned long)walk->iv & alignmask))) {
324 int err = blkcipher_copy_iv(walk, tfm, alignmask);
325 if (err)
326 return err;
329 scatterwalk_start(&walk->in, walk->in.sg);
330 scatterwalk_start(&walk->out, walk->out.sg);
331 walk->page = NULL;
333 return blkcipher_walk_next(desc, walk);
336 static int setkey(struct crypto_tfm *tfm, const u8 *key,
337 unsigned int keylen)
339 struct blkcipher_alg *cipher = &tfm->__crt_alg->cra_blkcipher;
341 if (keylen < cipher->min_keysize || keylen > cipher->max_keysize) {
342 tfm->crt_flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
343 return -EINVAL;
346 return cipher->setkey(tfm, key, keylen);
349 static unsigned int crypto_blkcipher_ctxsize(struct crypto_alg *alg)
351 struct blkcipher_alg *cipher = &alg->cra_blkcipher;
352 unsigned int len = alg->cra_ctxsize;
354 if (cipher->ivsize) {
355 len = ALIGN(len, (unsigned long)alg->cra_alignmask + 1);
356 len += cipher->ivsize;
359 return len;
362 static int crypto_init_blkcipher_ops(struct crypto_tfm *tfm)
364 struct blkcipher_tfm *crt = &tfm->crt_blkcipher;
365 struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher;
366 unsigned long align = crypto_tfm_alg_alignmask(tfm) + 1;
367 unsigned long addr;
369 if (alg->ivsize > PAGE_SIZE / 8)
370 return -EINVAL;
372 crt->setkey = setkey;
373 crt->encrypt = alg->encrypt;
374 crt->decrypt = alg->decrypt;
376 addr = (unsigned long)crypto_tfm_ctx(tfm);
377 addr = ALIGN(addr, align);
378 addr += ALIGN(tfm->__crt_alg->cra_ctxsize, align);
379 crt->iv = (void *)addr;
381 return 0;
384 static void crypto_blkcipher_show(struct seq_file *m, struct crypto_alg *alg)
385 __attribute_used__;
386 static void crypto_blkcipher_show(struct seq_file *m, struct crypto_alg *alg)
388 seq_printf(m, "type : blkcipher\n");
389 seq_printf(m, "blocksize : %u\n", alg->cra_blocksize);
390 seq_printf(m, "min keysize : %u\n", alg->cra_blkcipher.min_keysize);
391 seq_printf(m, "max keysize : %u\n", alg->cra_blkcipher.max_keysize);
392 seq_printf(m, "ivsize : %u\n", alg->cra_blkcipher.ivsize);
395 const struct crypto_type crypto_blkcipher_type = {
396 .ctxsize = crypto_blkcipher_ctxsize,
397 .init = crypto_init_blkcipher_ops,
398 #ifdef CONFIG_PROC_FS
399 .show = crypto_blkcipher_show,
400 #endif
402 EXPORT_SYMBOL_GPL(crypto_blkcipher_type);
404 MODULE_LICENSE("GPL");
405 MODULE_DESCRIPTION("Generic block chaining cipher type");