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
 24struct ablkcipher_buffer {
 25	struct list_head	entry;
 26	struct scatter_walk	dst;
 27	unsigned int		len;
 28	void			*data;
 29};
 30
 31enum {
 32	ABLKCIPHER_WALK_SLOW = 1 << 0,
 33};
 34
 35static inline void ablkcipher_buffer_write(struct ablkcipher_buffer *p)
 36{
 37	scatterwalk_copychunks(p->data, &p->dst, p->len, 1);
 38}
 39
 40void __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}
 50EXPORT_SYMBOL_GPL(__ablkcipher_walk_complete);
 51
 52static 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 */
 62static 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
 69static 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
 85static 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
 92static int ablkcipher_walk_next(struct ablkcipher_request *req,
 93				struct ablkcipher_walk *walk);
 94
 95int 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;
128finish:
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}
135EXPORT_SYMBOL_GPL(ablkcipher_walk_done);
136
137static 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
177static 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
202static 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
213static 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
247set_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
258static 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
287int 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}
293EXPORT_SYMBOL_GPL(ablkcipher_walk_phys);
294
295static 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
317static 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
334static unsigned int crypto_ablkcipher_ctxsize(struct crypto_alg *alg, u32 type,
335					      u32 mask)
336{
337	return alg->cra_ctxsize;
338}
339
340static 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
359static 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
377static int crypto_ablkcipher_report(struct sk_buff *skb, struct crypto_alg *alg)
378{
379	return -ENOSYS;
380}
381#endif
382
383static void crypto_ablkcipher_show(struct seq_file *m, struct crypto_alg *alg)
384	__maybe_unused;
385static 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
399const 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};
407EXPORT_SYMBOL_GPL(crypto_ablkcipher_type);