2 * RSA padding templates.
4 * Copyright (c) 2015 Intel Corporation
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License as published by the Free
8 * Software Foundation; either version 2 of the License, or (at your option)
12 #include <crypto/algapi.h>
13 #include <crypto/akcipher.h>
14 #include <crypto/internal/akcipher.h>
15 #include <linux/err.h>
16 #include <linux/init.h>
17 #include <linux/kernel.h>
18 #include <linux/module.h>
19 #include <linux/random.h>
22 * Hash algorithm OIDs plus ASN.1 DER wrappings [RFC4880 sec 5.2.2].
24 static const u8 rsa_digest_info_md5[] = {
25 0x30, 0x20, 0x30, 0x0c, 0x06, 0x08,
26 0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x02, 0x05, /* OID */
27 0x05, 0x00, 0x04, 0x10
30 static const u8 rsa_digest_info_sha1[] = {
31 0x30, 0x21, 0x30, 0x09, 0x06, 0x05,
32 0x2b, 0x0e, 0x03, 0x02, 0x1a,
33 0x05, 0x00, 0x04, 0x14
36 static const u8 rsa_digest_info_rmd160[] = {
37 0x30, 0x21, 0x30, 0x09, 0x06, 0x05,
38 0x2b, 0x24, 0x03, 0x02, 0x01,
39 0x05, 0x00, 0x04, 0x14
42 static const u8 rsa_digest_info_sha224[] = {
43 0x30, 0x2d, 0x30, 0x0d, 0x06, 0x09,
44 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x04,
45 0x05, 0x00, 0x04, 0x1c
48 static const u8 rsa_digest_info_sha256[] = {
49 0x30, 0x31, 0x30, 0x0d, 0x06, 0x09,
50 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x01,
51 0x05, 0x00, 0x04, 0x20
54 static const u8 rsa_digest_info_sha384[] = {
55 0x30, 0x41, 0x30, 0x0d, 0x06, 0x09,
56 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x02,
57 0x05, 0x00, 0x04, 0x30
60 static const u8 rsa_digest_info_sha512[] = {
61 0x30, 0x51, 0x30, 0x0d, 0x06, 0x09,
62 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x03,
63 0x05, 0x00, 0x04, 0x40
66 static const struct rsa_asn1_template {
70 } rsa_asn1_templates[] = {
71 #define _(X) { #X, rsa_digest_info_##X, sizeof(rsa_digest_info_##X) }
83 static const struct rsa_asn1_template *rsa_lookup_asn1(const char *name)
85 const struct rsa_asn1_template *p;
87 for (p = rsa_asn1_templates; p->name; p++)
88 if (strcmp(name, p->name) == 0)
94 struct crypto_akcipher *child;
95 unsigned int key_size;
98 struct pkcs1pad_inst_ctx {
99 struct crypto_akcipher_spawn spawn;
100 const struct rsa_asn1_template *digest_info;
103 struct pkcs1pad_request {
104 struct akcipher_request child_req;
106 struct scatterlist in_sg[2], out_sg[1];
107 uint8_t *in_buf, *out_buf;
110 static int pkcs1pad_set_pub_key(struct crypto_akcipher *tfm, const void *key,
113 struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
116 err = crypto_akcipher_set_pub_key(ctx->child, key, keylen);
119 /* Find out new modulus size from rsa implementation */
120 size = crypto_akcipher_maxsize(ctx->child);
122 ctx->key_size = size > 0 ? size : 0;
130 static int pkcs1pad_set_priv_key(struct crypto_akcipher *tfm, const void *key,
133 struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
136 err = crypto_akcipher_set_priv_key(ctx->child, key, keylen);
139 /* Find out new modulus size from rsa implementation */
140 size = crypto_akcipher_maxsize(ctx->child);
142 ctx->key_size = size > 0 ? size : 0;
150 static int pkcs1pad_get_max_size(struct crypto_akcipher *tfm)
152 struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
155 * The maximum destination buffer size for the encrypt/sign operations
156 * will be the same as for RSA, even though it's smaller for
160 return ctx->key_size ?: -EINVAL;
163 static void pkcs1pad_sg_set_buf(struct scatterlist *sg, void *buf, size_t len,
164 struct scatterlist *next)
166 int nsegs = next ? 2 : 1;
168 sg_init_table(sg, nsegs);
169 sg_set_buf(sg, buf, len);
172 sg_chain(sg, nsegs, next);
175 static int pkcs1pad_encrypt_sign_complete(struct akcipher_request *req, int err)
177 struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
178 struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
179 struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
180 size_t pad_len = ctx->key_size - req_ctx->child_req.dst_len;
181 size_t chunk_len, pad_left;
182 struct sg_mapping_iter miter;
186 sg_miter_start(&miter, req->dst,
187 sg_nents_for_len(req->dst, pad_len),
188 SG_MITER_ATOMIC | SG_MITER_TO_SG);
192 sg_miter_next(&miter);
194 chunk_len = min(miter.length, pad_left);
195 memset(miter.addr, 0, chunk_len);
196 pad_left -= chunk_len;
199 sg_miter_stop(&miter);
202 sg_pcopy_from_buffer(req->dst,
203 sg_nents_for_len(req->dst, ctx->key_size),
204 req_ctx->out_buf, req_ctx->child_req.dst_len,
207 req->dst_len = ctx->key_size;
209 kfree(req_ctx->in_buf);
210 kzfree(req_ctx->out_buf);
215 static void pkcs1pad_encrypt_sign_complete_cb(
216 struct crypto_async_request *child_async_req, int err)
218 struct akcipher_request *req = child_async_req->data;
219 struct crypto_async_request async_req;
221 if (err == -EINPROGRESS)
224 async_req.data = req->base.data;
225 async_req.tfm = crypto_akcipher_tfm(crypto_akcipher_reqtfm(req));
226 async_req.flags = child_async_req->flags;
227 req->base.complete(&async_req,
228 pkcs1pad_encrypt_sign_complete(req, err));
231 static int pkcs1pad_encrypt(struct akcipher_request *req)
233 struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
234 struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
235 struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
237 unsigned int i, ps_end;
242 if (req->src_len > ctx->key_size - 11)
245 if (req->dst_len < ctx->key_size) {
246 req->dst_len = ctx->key_size;
250 if (ctx->key_size > PAGE_SIZE)
254 * Replace both input and output to add the padding in the input and
255 * the potential missing leading zeros in the output.
257 req_ctx->child_req.src = req_ctx->in_sg;
258 req_ctx->child_req.src_len = ctx->key_size - 1;
259 req_ctx->child_req.dst = req_ctx->out_sg;
260 req_ctx->child_req.dst_len = ctx->key_size;
262 req_ctx->in_buf = kmalloc(ctx->key_size - 1 - req->src_len,
264 if (!req_ctx->in_buf)
267 ps_end = ctx->key_size - req->src_len - 2;
268 req_ctx->in_buf[0] = 0x02;
269 for (i = 1; i < ps_end; i++)
270 req_ctx->in_buf[i] = 1 + prandom_u32_max(255);
271 req_ctx->in_buf[ps_end] = 0x00;
273 pkcs1pad_sg_set_buf(req_ctx->in_sg, req_ctx->in_buf,
274 ctx->key_size - 1 - req->src_len, req->src);
276 req_ctx->out_buf = kmalloc(ctx->key_size, GFP_KERNEL);
277 if (!req_ctx->out_buf) {
278 kfree(req_ctx->in_buf);
282 pkcs1pad_sg_set_buf(req_ctx->out_sg, req_ctx->out_buf,
283 ctx->key_size, NULL);
285 akcipher_request_set_tfm(&req_ctx->child_req, ctx->child);
286 akcipher_request_set_callback(&req_ctx->child_req, req->base.flags,
287 pkcs1pad_encrypt_sign_complete_cb, req);
289 err = crypto_akcipher_encrypt(&req_ctx->child_req);
290 if (err != -EINPROGRESS &&
292 !(req->base.flags & CRYPTO_TFM_REQ_MAY_BACKLOG)))
293 return pkcs1pad_encrypt_sign_complete(req, err);
298 static int pkcs1pad_decrypt_complete(struct akcipher_request *req, int err)
300 struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
301 struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
302 struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
305 if (err == -EOVERFLOW)
306 /* Decrypted value had no leading 0 byte */
312 if (req_ctx->child_req.dst_len != ctx->key_size - 1) {
317 if (req_ctx->out_buf[0] != 0x02) {
321 for (pos = 1; pos < req_ctx->child_req.dst_len; pos++)
322 if (req_ctx->out_buf[pos] == 0x00)
324 if (pos < 9 || pos == req_ctx->child_req.dst_len) {
330 if (req->dst_len < req_ctx->child_req.dst_len - pos)
332 req->dst_len = req_ctx->child_req.dst_len - pos;
335 sg_copy_from_buffer(req->dst,
336 sg_nents_for_len(req->dst, req->dst_len),
337 req_ctx->out_buf + pos, req->dst_len);
340 kzfree(req_ctx->out_buf);
345 static void pkcs1pad_decrypt_complete_cb(
346 struct crypto_async_request *child_async_req, int err)
348 struct akcipher_request *req = child_async_req->data;
349 struct crypto_async_request async_req;
351 if (err == -EINPROGRESS)
354 async_req.data = req->base.data;
355 async_req.tfm = crypto_akcipher_tfm(crypto_akcipher_reqtfm(req));
356 async_req.flags = child_async_req->flags;
357 req->base.complete(&async_req, pkcs1pad_decrypt_complete(req, err));
360 static int pkcs1pad_decrypt(struct akcipher_request *req)
362 struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
363 struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
364 struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
367 if (!ctx->key_size || req->src_len != ctx->key_size)
370 if (ctx->key_size > PAGE_SIZE)
373 /* Reuse input buffer, output to a new buffer */
374 req_ctx->child_req.src = req->src;
375 req_ctx->child_req.src_len = req->src_len;
376 req_ctx->child_req.dst = req_ctx->out_sg;
377 req_ctx->child_req.dst_len = ctx->key_size ;
379 req_ctx->out_buf = kmalloc(ctx->key_size, GFP_KERNEL);
380 if (!req_ctx->out_buf)
383 pkcs1pad_sg_set_buf(req_ctx->out_sg, req_ctx->out_buf,
384 ctx->key_size, NULL);
386 akcipher_request_set_tfm(&req_ctx->child_req, ctx->child);
387 akcipher_request_set_callback(&req_ctx->child_req, req->base.flags,
388 pkcs1pad_decrypt_complete_cb, req);
390 err = crypto_akcipher_decrypt(&req_ctx->child_req);
391 if (err != -EINPROGRESS &&
393 !(req->base.flags & CRYPTO_TFM_REQ_MAY_BACKLOG)))
394 return pkcs1pad_decrypt_complete(req, err);
399 static int pkcs1pad_sign(struct akcipher_request *req)
401 struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
402 struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
403 struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
404 struct akcipher_instance *inst = akcipher_alg_instance(tfm);
405 struct pkcs1pad_inst_ctx *ictx = akcipher_instance_ctx(inst);
406 const struct rsa_asn1_template *digest_info = ictx->digest_info;
408 unsigned int ps_end, digest_size = 0;
413 digest_size = digest_info->size;
415 if (req->src_len + digest_size > ctx->key_size - 11)
418 if (req->dst_len < ctx->key_size) {
419 req->dst_len = ctx->key_size;
423 if (ctx->key_size > PAGE_SIZE)
427 * Replace both input and output to add the padding in the input and
428 * the potential missing leading zeros in the output.
430 req_ctx->child_req.src = req_ctx->in_sg;
431 req_ctx->child_req.src_len = ctx->key_size - 1;
432 req_ctx->child_req.dst = req_ctx->out_sg;
433 req_ctx->child_req.dst_len = ctx->key_size;
435 req_ctx->in_buf = kmalloc(ctx->key_size - 1 - req->src_len,
437 if (!req_ctx->in_buf)
440 ps_end = ctx->key_size - digest_size - req->src_len - 2;
441 req_ctx->in_buf[0] = 0x01;
442 memset(req_ctx->in_buf + 1, 0xff, ps_end - 1);
443 req_ctx->in_buf[ps_end] = 0x00;
445 memcpy(req_ctx->in_buf + ps_end + 1, digest_info->data,
448 pkcs1pad_sg_set_buf(req_ctx->in_sg, req_ctx->in_buf,
449 ctx->key_size - 1 - req->src_len, req->src);
451 req_ctx->out_buf = kmalloc(ctx->key_size, GFP_KERNEL);
452 if (!req_ctx->out_buf) {
453 kfree(req_ctx->in_buf);
457 pkcs1pad_sg_set_buf(req_ctx->out_sg, req_ctx->out_buf,
458 ctx->key_size, NULL);
460 akcipher_request_set_tfm(&req_ctx->child_req, ctx->child);
461 akcipher_request_set_callback(&req_ctx->child_req, req->base.flags,
462 pkcs1pad_encrypt_sign_complete_cb, req);
464 err = crypto_akcipher_sign(&req_ctx->child_req);
465 if (err != -EINPROGRESS &&
467 !(req->base.flags & CRYPTO_TFM_REQ_MAY_BACKLOG)))
468 return pkcs1pad_encrypt_sign_complete(req, err);
473 static int pkcs1pad_verify_complete(struct akcipher_request *req, int err)
475 struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
476 struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
477 struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
478 struct akcipher_instance *inst = akcipher_alg_instance(tfm);
479 struct pkcs1pad_inst_ctx *ictx = akcipher_instance_ctx(inst);
480 const struct rsa_asn1_template *digest_info = ictx->digest_info;
483 if (err == -EOVERFLOW)
484 /* Decrypted value had no leading 0 byte */
490 if (req_ctx->child_req.dst_len != ctx->key_size - 1) {
496 if (req_ctx->out_buf[0] != 0x01)
499 for (pos = 1; pos < req_ctx->child_req.dst_len; pos++)
500 if (req_ctx->out_buf[pos] != 0xff)
503 if (pos < 9 || pos == req_ctx->child_req.dst_len ||
504 req_ctx->out_buf[pos] != 0x00)
508 if (memcmp(req_ctx->out_buf + pos, digest_info->data,
512 pos += digest_info->size;
516 if (req->dst_len < req_ctx->child_req.dst_len - pos)
518 req->dst_len = req_ctx->child_req.dst_len - pos;
521 sg_copy_from_buffer(req->dst,
522 sg_nents_for_len(req->dst, req->dst_len),
523 req_ctx->out_buf + pos, req->dst_len);
525 kzfree(req_ctx->out_buf);
530 static void pkcs1pad_verify_complete_cb(
531 struct crypto_async_request *child_async_req, int err)
533 struct akcipher_request *req = child_async_req->data;
534 struct crypto_async_request async_req;
536 if (err == -EINPROGRESS)
539 async_req.data = req->base.data;
540 async_req.tfm = crypto_akcipher_tfm(crypto_akcipher_reqtfm(req));
541 async_req.flags = child_async_req->flags;
542 req->base.complete(&async_req, pkcs1pad_verify_complete(req, err));
546 * The verify operation is here for completeness similar to the verification
547 * defined in RFC2313 section 10.2 except that block type 0 is not accepted,
548 * as in RFC2437. RFC2437 section 9.2 doesn't define any operation to
549 * retrieve the DigestInfo from a signature, instead the user is expected
550 * to call the sign operation to generate the expected signature and compare
551 * signatures instead of the message-digests.
553 static int pkcs1pad_verify(struct akcipher_request *req)
555 struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
556 struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
557 struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
560 if (!ctx->key_size || req->src_len < ctx->key_size)
563 if (ctx->key_size > PAGE_SIZE)
566 /* Reuse input buffer, output to a new buffer */
567 req_ctx->child_req.src = req->src;
568 req_ctx->child_req.src_len = req->src_len;
569 req_ctx->child_req.dst = req_ctx->out_sg;
570 req_ctx->child_req.dst_len = ctx->key_size;
572 req_ctx->out_buf = kmalloc(ctx->key_size, GFP_KERNEL);
573 if (!req_ctx->out_buf)
576 pkcs1pad_sg_set_buf(req_ctx->out_sg, req_ctx->out_buf,
577 ctx->key_size, NULL);
579 akcipher_request_set_tfm(&req_ctx->child_req, ctx->child);
580 akcipher_request_set_callback(&req_ctx->child_req, req->base.flags,
581 pkcs1pad_verify_complete_cb, req);
583 err = crypto_akcipher_verify(&req_ctx->child_req);
584 if (err != -EINPROGRESS &&
586 !(req->base.flags & CRYPTO_TFM_REQ_MAY_BACKLOG)))
587 return pkcs1pad_verify_complete(req, err);
592 static int pkcs1pad_init_tfm(struct crypto_akcipher *tfm)
594 struct akcipher_instance *inst = akcipher_alg_instance(tfm);
595 struct pkcs1pad_inst_ctx *ictx = akcipher_instance_ctx(inst);
596 struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
597 struct crypto_akcipher *child_tfm;
599 child_tfm = crypto_spawn_akcipher(&ictx->spawn);
600 if (IS_ERR(child_tfm))
601 return PTR_ERR(child_tfm);
603 ctx->child = child_tfm;
607 static void pkcs1pad_exit_tfm(struct crypto_akcipher *tfm)
609 struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
611 crypto_free_akcipher(ctx->child);
614 static void pkcs1pad_free(struct akcipher_instance *inst)
616 struct pkcs1pad_inst_ctx *ctx = akcipher_instance_ctx(inst);
617 struct crypto_akcipher_spawn *spawn = &ctx->spawn;
619 crypto_drop_akcipher(spawn);
623 static int pkcs1pad_create(struct crypto_template *tmpl, struct rtattr **tb)
625 const struct rsa_asn1_template *digest_info;
626 struct crypto_attr_type *algt;
627 struct akcipher_instance *inst;
628 struct pkcs1pad_inst_ctx *ctx;
629 struct crypto_akcipher_spawn *spawn;
630 struct akcipher_alg *rsa_alg;
631 const char *rsa_alg_name;
632 const char *hash_name;
635 algt = crypto_get_attr_type(tb);
637 return PTR_ERR(algt);
639 if ((algt->type ^ CRYPTO_ALG_TYPE_AKCIPHER) & algt->mask)
642 rsa_alg_name = crypto_attr_alg_name(tb[1]);
643 if (IS_ERR(rsa_alg_name))
644 return PTR_ERR(rsa_alg_name);
646 hash_name = crypto_attr_alg_name(tb[2]);
647 if (IS_ERR(hash_name))
648 return PTR_ERR(hash_name);
650 digest_info = rsa_lookup_asn1(hash_name);
654 inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
658 ctx = akcipher_instance_ctx(inst);
660 ctx->digest_info = digest_info;
662 crypto_set_spawn(&spawn->base, akcipher_crypto_instance(inst));
663 err = crypto_grab_akcipher(spawn, rsa_alg_name, 0,
664 crypto_requires_sync(algt->type, algt->mask));
668 rsa_alg = crypto_spawn_akcipher_alg(spawn);
672 if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
673 "pkcs1pad(%s,%s)", rsa_alg->base.cra_name, hash_name) >=
674 CRYPTO_MAX_ALG_NAME ||
675 snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
677 rsa_alg->base.cra_driver_name, hash_name) >=
681 inst->alg.base.cra_flags = rsa_alg->base.cra_flags & CRYPTO_ALG_ASYNC;
682 inst->alg.base.cra_priority = rsa_alg->base.cra_priority;
683 inst->alg.base.cra_ctxsize = sizeof(struct pkcs1pad_ctx);
685 inst->alg.init = pkcs1pad_init_tfm;
686 inst->alg.exit = pkcs1pad_exit_tfm;
688 inst->alg.encrypt = pkcs1pad_encrypt;
689 inst->alg.decrypt = pkcs1pad_decrypt;
690 inst->alg.sign = pkcs1pad_sign;
691 inst->alg.verify = pkcs1pad_verify;
692 inst->alg.set_pub_key = pkcs1pad_set_pub_key;
693 inst->alg.set_priv_key = pkcs1pad_set_priv_key;
694 inst->alg.max_size = pkcs1pad_get_max_size;
695 inst->alg.reqsize = sizeof(struct pkcs1pad_request) + rsa_alg->reqsize;
697 inst->free = pkcs1pad_free;
699 err = akcipher_register_instance(tmpl, inst);
706 crypto_drop_akcipher(spawn);
712 struct crypto_template rsa_pkcs1pad_tmpl = {
714 .create = pkcs1pad_create,
715 .module = THIS_MODULE,