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 
ablkcipher_buffer_write(struct ablkcipher_buffer * p)35 static inline void ablkcipher_buffer_write(struct ablkcipher_buffer *p)
36 {
37 	scatterwalk_copychunks(p->data, &p->dst, p->len, 1);
38 }
39 
__ablkcipher_walk_complete(struct ablkcipher_walk * walk)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 
ablkcipher_queue_write(struct ablkcipher_walk * walk,struct ablkcipher_buffer * p)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  */
ablkcipher_get_spot(u8 * start,unsigned int len)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 
ablkcipher_done_slow(struct ablkcipher_walk * walk,unsigned int n)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 
ablkcipher_done_fast(struct ablkcipher_walk * walk,unsigned int n)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 
ablkcipher_walk_done(struct ablkcipher_request * req,struct ablkcipher_walk * walk,int err)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 
ablkcipher_next_slow(struct ablkcipher_request * req,struct ablkcipher_walk * walk,unsigned int bsize,unsigned int alignmask,void ** src_p,void ** dst_p)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 
ablkcipher_copy_iv(struct ablkcipher_walk * walk,struct crypto_tfm * tfm,unsigned int alignmask)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 
ablkcipher_next_fast(struct ablkcipher_request * req,struct ablkcipher_walk * walk)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 
ablkcipher_walk_next(struct ablkcipher_request * req,struct ablkcipher_walk * walk)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 
ablkcipher_walk_first(struct ablkcipher_request * req,struct ablkcipher_walk * walk)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 
ablkcipher_walk_phys(struct ablkcipher_request * req,struct ablkcipher_walk * walk)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 
setkey_unaligned(struct crypto_ablkcipher * tfm,const u8 * key,unsigned int keylen)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 
setkey(struct crypto_ablkcipher * tfm,const u8 * key,unsigned int keylen)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 
crypto_ablkcipher_ctxsize(struct crypto_alg * alg,u32 type,u32 mask)334 static unsigned int crypto_ablkcipher_ctxsize(struct crypto_alg *alg, u32 type,
335 					      u32 mask)
336 {
337 	return alg->cra_ctxsize;
338 }
339 
crypto_init_ablkcipher_ops(struct crypto_tfm * tfm,u32 type,u32 mask)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
crypto_ablkcipher_report(struct sk_buff * skb,struct crypto_alg * alg)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
crypto_ablkcipher_report(struct sk_buff * skb,struct crypto_alg * alg)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;
crypto_ablkcipher_show(struct seq_file * m,struct crypto_alg * alg)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);
408