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);
118 err = crypto_akcipher_set_pub_key(ctx->child, key, keylen);
122 /* Find out new modulus size from rsa implementation */
123 err = crypto_akcipher_maxsize(ctx->child);
134 static int pkcs1pad_set_priv_key(struct crypto_akcipher *tfm, const void *key,
137 struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
142 err = crypto_akcipher_set_priv_key(ctx->child, key, keylen);
146 /* Find out new modulus size from rsa implementation */
147 err = crypto_akcipher_maxsize(ctx->child);
158 static int pkcs1pad_get_max_size(struct crypto_akcipher *tfm)
160 struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
163 * The maximum destination buffer size for the encrypt/sign operations
164 * will be the same as for RSA, even though it's smaller for
168 return ctx->key_size ?: -EINVAL;
171 static void pkcs1pad_sg_set_buf(struct scatterlist *sg, void *buf, size_t len,
172 struct scatterlist *next)
174 int nsegs = next ? 2 : 1;
176 sg_init_table(sg, nsegs);
177 sg_set_buf(sg, buf, len);
180 sg_chain(sg, nsegs, next);
183 static int pkcs1pad_encrypt_sign_complete(struct akcipher_request *req, int err)
185 struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
186 struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
187 struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
188 size_t pad_len = ctx->key_size - req_ctx->child_req.dst_len;
189 size_t chunk_len, pad_left;
190 struct sg_mapping_iter miter;
194 sg_miter_start(&miter, req->dst,
195 sg_nents_for_len(req->dst, pad_len),
196 SG_MITER_ATOMIC | SG_MITER_TO_SG);
200 sg_miter_next(&miter);
202 chunk_len = min(miter.length, pad_left);
203 memset(miter.addr, 0, chunk_len);
204 pad_left -= chunk_len;
207 sg_miter_stop(&miter);
210 sg_pcopy_from_buffer(req->dst,
211 sg_nents_for_len(req->dst, ctx->key_size),
212 req_ctx->out_buf, req_ctx->child_req.dst_len,
215 req->dst_len = ctx->key_size;
217 kfree(req_ctx->in_buf);
218 kzfree(req_ctx->out_buf);
223 static void pkcs1pad_encrypt_sign_complete_cb(
224 struct crypto_async_request *child_async_req, int err)
226 struct akcipher_request *req = child_async_req->data;
227 struct crypto_async_request async_req;
229 if (err == -EINPROGRESS)
232 async_req.data = req->base.data;
233 async_req.tfm = crypto_akcipher_tfm(crypto_akcipher_reqtfm(req));
234 async_req.flags = child_async_req->flags;
235 req->base.complete(&async_req,
236 pkcs1pad_encrypt_sign_complete(req, err));
239 static int pkcs1pad_encrypt(struct akcipher_request *req)
241 struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
242 struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
243 struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
245 unsigned int i, ps_end;
250 if (req->src_len > ctx->key_size - 11)
253 if (req->dst_len < ctx->key_size) {
254 req->dst_len = ctx->key_size;
259 * Replace both input and output to add the padding in the input and
260 * the potential missing leading zeros in the output.
262 req_ctx->child_req.src = req_ctx->in_sg;
263 req_ctx->child_req.src_len = ctx->key_size - 1;
264 req_ctx->child_req.dst = req_ctx->out_sg;
265 req_ctx->child_req.dst_len = ctx->key_size;
267 req_ctx->in_buf = kmalloc(ctx->key_size - 1 - req->src_len,
269 if (!req_ctx->in_buf)
272 ps_end = ctx->key_size - req->src_len - 2;
273 req_ctx->in_buf[0] = 0x02;
274 for (i = 1; i < ps_end; i++)
275 req_ctx->in_buf[i] = 1 + prandom_u32_max(255);
276 req_ctx->in_buf[ps_end] = 0x00;
278 pkcs1pad_sg_set_buf(req_ctx->in_sg, req_ctx->in_buf,
279 ctx->key_size - 1 - req->src_len, req->src);
281 req_ctx->out_buf = kmalloc(ctx->key_size, GFP_KERNEL);
282 if (!req_ctx->out_buf) {
283 kfree(req_ctx->in_buf);
287 pkcs1pad_sg_set_buf(req_ctx->out_sg, req_ctx->out_buf,
288 ctx->key_size, NULL);
290 akcipher_request_set_tfm(&req_ctx->child_req, ctx->child);
291 akcipher_request_set_callback(&req_ctx->child_req, req->base.flags,
292 pkcs1pad_encrypt_sign_complete_cb, req);
294 err = crypto_akcipher_encrypt(&req_ctx->child_req);
295 if (err != -EINPROGRESS &&
297 !(req->base.flags & CRYPTO_TFM_REQ_MAY_BACKLOG)))
298 return pkcs1pad_encrypt_sign_complete(req, err);
303 static int pkcs1pad_decrypt_complete(struct akcipher_request *req, int err)
305 struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
306 struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
307 struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
310 if (err == -EOVERFLOW)
311 /* Decrypted value had no leading 0 byte */
317 if (req_ctx->child_req.dst_len != ctx->key_size - 1) {
322 if (req_ctx->out_buf[0] != 0x02) {
326 for (pos = 1; pos < req_ctx->child_req.dst_len; pos++)
327 if (req_ctx->out_buf[pos] == 0x00)
329 if (pos < 9 || pos == req_ctx->child_req.dst_len) {
335 if (req->dst_len < req_ctx->child_req.dst_len - pos)
337 req->dst_len = req_ctx->child_req.dst_len - pos;
340 sg_copy_from_buffer(req->dst,
341 sg_nents_for_len(req->dst, req->dst_len),
342 req_ctx->out_buf + pos, req->dst_len);
345 kzfree(req_ctx->out_buf);
350 static void pkcs1pad_decrypt_complete_cb(
351 struct crypto_async_request *child_async_req, int err)
353 struct akcipher_request *req = child_async_req->data;
354 struct crypto_async_request async_req;
356 if (err == -EINPROGRESS)
359 async_req.data = req->base.data;
360 async_req.tfm = crypto_akcipher_tfm(crypto_akcipher_reqtfm(req));
361 async_req.flags = child_async_req->flags;
362 req->base.complete(&async_req, pkcs1pad_decrypt_complete(req, err));
365 static int pkcs1pad_decrypt(struct akcipher_request *req)
367 struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
368 struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
369 struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
372 if (!ctx->key_size || req->src_len != ctx->key_size)
375 /* Reuse input buffer, output to a new buffer */
376 req_ctx->child_req.src = req->src;
377 req_ctx->child_req.src_len = req->src_len;
378 req_ctx->child_req.dst = req_ctx->out_sg;
379 req_ctx->child_req.dst_len = ctx->key_size ;
381 req_ctx->out_buf = kmalloc(ctx->key_size, GFP_KERNEL);
382 if (!req_ctx->out_buf)
385 pkcs1pad_sg_set_buf(req_ctx->out_sg, req_ctx->out_buf,
386 ctx->key_size, NULL);
388 akcipher_request_set_tfm(&req_ctx->child_req, ctx->child);
389 akcipher_request_set_callback(&req_ctx->child_req, req->base.flags,
390 pkcs1pad_decrypt_complete_cb, req);
392 err = crypto_akcipher_decrypt(&req_ctx->child_req);
393 if (err != -EINPROGRESS &&
395 !(req->base.flags & CRYPTO_TFM_REQ_MAY_BACKLOG)))
396 return pkcs1pad_decrypt_complete(req, err);
401 static int pkcs1pad_sign(struct akcipher_request *req)
403 struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
404 struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
405 struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
406 struct akcipher_instance *inst = akcipher_alg_instance(tfm);
407 struct pkcs1pad_inst_ctx *ictx = akcipher_instance_ctx(inst);
408 const struct rsa_asn1_template *digest_info = ictx->digest_info;
410 unsigned int ps_end, digest_size = 0;
415 digest_size = digest_info->size;
417 if (req->src_len + digest_size > ctx->key_size - 11)
420 if (req->dst_len < ctx->key_size) {
421 req->dst_len = ctx->key_size;
426 * Replace both input and output to add the padding in the input and
427 * the potential missing leading zeros in the output.
429 req_ctx->child_req.src = req_ctx->in_sg;
430 req_ctx->child_req.src_len = ctx->key_size - 1;
431 req_ctx->child_req.dst = req_ctx->out_sg;
432 req_ctx->child_req.dst_len = ctx->key_size;
434 req_ctx->in_buf = kmalloc(ctx->key_size - 1 - req->src_len,
436 if (!req_ctx->in_buf)
439 ps_end = ctx->key_size - digest_size - req->src_len - 2;
440 req_ctx->in_buf[0] = 0x01;
441 memset(req_ctx->in_buf + 1, 0xff, ps_end - 1);
442 req_ctx->in_buf[ps_end] = 0x00;
444 memcpy(req_ctx->in_buf + ps_end + 1, digest_info->data,
447 pkcs1pad_sg_set_buf(req_ctx->in_sg, req_ctx->in_buf,
448 ctx->key_size - 1 - req->src_len, req->src);
450 req_ctx->out_buf = kmalloc(ctx->key_size, GFP_KERNEL);
451 if (!req_ctx->out_buf) {
452 kfree(req_ctx->in_buf);
456 pkcs1pad_sg_set_buf(req_ctx->out_sg, req_ctx->out_buf,
457 ctx->key_size, NULL);
459 akcipher_request_set_tfm(&req_ctx->child_req, ctx->child);
460 akcipher_request_set_callback(&req_ctx->child_req, req->base.flags,
461 pkcs1pad_encrypt_sign_complete_cb, req);
463 err = crypto_akcipher_sign(&req_ctx->child_req);
464 if (err != -EINPROGRESS &&
466 !(req->base.flags & CRYPTO_TFM_REQ_MAY_BACKLOG)))
467 return pkcs1pad_encrypt_sign_complete(req, err);
472 static int pkcs1pad_verify_complete(struct akcipher_request *req, int err)
474 struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
475 struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
476 struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
477 struct akcipher_instance *inst = akcipher_alg_instance(tfm);
478 struct pkcs1pad_inst_ctx *ictx = akcipher_instance_ctx(inst);
479 const struct rsa_asn1_template *digest_info = ictx->digest_info;
482 if (err == -EOVERFLOW)
483 /* Decrypted value had no leading 0 byte */
489 if (req_ctx->child_req.dst_len != ctx->key_size - 1) {
495 if (req_ctx->out_buf[0] != 0x01)
498 for (pos = 1; pos < req_ctx->child_req.dst_len; pos++)
499 if (req_ctx->out_buf[pos] != 0xff)
502 if (pos < 9 || pos == req_ctx->child_req.dst_len ||
503 req_ctx->out_buf[pos] != 0x00)
507 if (memcmp(req_ctx->out_buf + pos, digest_info->data,
511 pos += digest_info->size;
515 if (req->dst_len < req_ctx->child_req.dst_len - pos)
517 req->dst_len = req_ctx->child_req.dst_len - pos;
520 sg_copy_from_buffer(req->dst,
521 sg_nents_for_len(req->dst, req->dst_len),
522 req_ctx->out_buf + pos, req->dst_len);
524 kzfree(req_ctx->out_buf);
529 static void pkcs1pad_verify_complete_cb(
530 struct crypto_async_request *child_async_req, int err)
532 struct akcipher_request *req = child_async_req->data;
533 struct crypto_async_request async_req;
535 if (err == -EINPROGRESS)
538 async_req.data = req->base.data;
539 async_req.tfm = crypto_akcipher_tfm(crypto_akcipher_reqtfm(req));
540 async_req.flags = child_async_req->flags;
541 req->base.complete(&async_req, pkcs1pad_verify_complete(req, err));
545 * The verify operation is here for completeness similar to the verification
546 * defined in RFC2313 section 10.2 except that block type 0 is not accepted,
547 * as in RFC2437. RFC2437 section 9.2 doesn't define any operation to
548 * retrieve the DigestInfo from a signature, instead the user is expected
549 * to call the sign operation to generate the expected signature and compare
550 * signatures instead of the message-digests.
552 static int pkcs1pad_verify(struct akcipher_request *req)
554 struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
555 struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
556 struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
559 if (!ctx->key_size || req->src_len < ctx->key_size)
562 /* Reuse input buffer, output to a new buffer */
563 req_ctx->child_req.src = req->src;
564 req_ctx->child_req.src_len = req->src_len;
565 req_ctx->child_req.dst = req_ctx->out_sg;
566 req_ctx->child_req.dst_len = ctx->key_size;
568 req_ctx->out_buf = kmalloc(ctx->key_size, GFP_KERNEL);
569 if (!req_ctx->out_buf)
572 pkcs1pad_sg_set_buf(req_ctx->out_sg, req_ctx->out_buf,
573 ctx->key_size, NULL);
575 akcipher_request_set_tfm(&req_ctx->child_req, ctx->child);
576 akcipher_request_set_callback(&req_ctx->child_req, req->base.flags,
577 pkcs1pad_verify_complete_cb, req);
579 err = crypto_akcipher_verify(&req_ctx->child_req);
580 if (err != -EINPROGRESS &&
582 !(req->base.flags & CRYPTO_TFM_REQ_MAY_BACKLOG)))
583 return pkcs1pad_verify_complete(req, err);
588 static int pkcs1pad_init_tfm(struct crypto_akcipher *tfm)
590 struct akcipher_instance *inst = akcipher_alg_instance(tfm);
591 struct pkcs1pad_inst_ctx *ictx = akcipher_instance_ctx(inst);
592 struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
593 struct crypto_akcipher *child_tfm;
595 child_tfm = crypto_spawn_akcipher(&ictx->spawn);
596 if (IS_ERR(child_tfm))
597 return PTR_ERR(child_tfm);
599 ctx->child = child_tfm;
603 static void pkcs1pad_exit_tfm(struct crypto_akcipher *tfm)
605 struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
607 crypto_free_akcipher(ctx->child);
610 static void pkcs1pad_free(struct akcipher_instance *inst)
612 struct pkcs1pad_inst_ctx *ctx = akcipher_instance_ctx(inst);
613 struct crypto_akcipher_spawn *spawn = &ctx->spawn;
615 crypto_drop_akcipher(spawn);
619 static int pkcs1pad_create(struct crypto_template *tmpl, struct rtattr **tb)
621 const struct rsa_asn1_template *digest_info;
622 struct crypto_attr_type *algt;
623 struct akcipher_instance *inst;
624 struct pkcs1pad_inst_ctx *ctx;
625 struct crypto_akcipher_spawn *spawn;
626 struct akcipher_alg *rsa_alg;
627 const char *rsa_alg_name;
628 const char *hash_name;
631 algt = crypto_get_attr_type(tb);
633 return PTR_ERR(algt);
635 if ((algt->type ^ CRYPTO_ALG_TYPE_AKCIPHER) & algt->mask)
638 rsa_alg_name = crypto_attr_alg_name(tb[1]);
639 if (IS_ERR(rsa_alg_name))
640 return PTR_ERR(rsa_alg_name);
642 hash_name = crypto_attr_alg_name(tb[2]);
643 if (IS_ERR(hash_name))
644 return PTR_ERR(hash_name);
646 digest_info = rsa_lookup_asn1(hash_name);
650 inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
654 ctx = akcipher_instance_ctx(inst);
656 ctx->digest_info = digest_info;
658 crypto_set_spawn(&spawn->base, akcipher_crypto_instance(inst));
659 err = crypto_grab_akcipher(spawn, rsa_alg_name, 0,
660 crypto_requires_sync(algt->type, algt->mask));
664 rsa_alg = crypto_spawn_akcipher_alg(spawn);
668 if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
669 "pkcs1pad(%s,%s)", rsa_alg->base.cra_name, hash_name) >=
670 CRYPTO_MAX_ALG_NAME ||
671 snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
673 rsa_alg->base.cra_driver_name, hash_name) >=
677 inst->alg.base.cra_flags = rsa_alg->base.cra_flags & CRYPTO_ALG_ASYNC;
678 inst->alg.base.cra_priority = rsa_alg->base.cra_priority;
679 inst->alg.base.cra_ctxsize = sizeof(struct pkcs1pad_ctx);
681 inst->alg.init = pkcs1pad_init_tfm;
682 inst->alg.exit = pkcs1pad_exit_tfm;
684 inst->alg.encrypt = pkcs1pad_encrypt;
685 inst->alg.decrypt = pkcs1pad_decrypt;
686 inst->alg.sign = pkcs1pad_sign;
687 inst->alg.verify = pkcs1pad_verify;
688 inst->alg.set_pub_key = pkcs1pad_set_pub_key;
689 inst->alg.set_priv_key = pkcs1pad_set_priv_key;
690 inst->alg.max_size = pkcs1pad_get_max_size;
691 inst->alg.reqsize = sizeof(struct pkcs1pad_request) + rsa_alg->reqsize;
693 inst->free = pkcs1pad_free;
695 err = akcipher_register_instance(tmpl, inst);
702 crypto_drop_akcipher(spawn);
708 struct crypto_template rsa_pkcs1pad_tmpl = {
710 .create = pkcs1pad_create,
711 .module = THIS_MODULE,