1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * RSA padding templates.
5 * Copyright (c) 2015 Intel Corporation
8 #include <crypto/algapi.h>
9 #include <crypto/akcipher.h>
10 #include <crypto/internal/akcipher.h>
11 #include <crypto/internal/rsa.h>
12 #include <linux/err.h>
13 #include <linux/init.h>
14 #include <linux/kernel.h>
15 #include <linux/module.h>
16 #include <linux/random.h>
17 #include <linux/scatterlist.h>
20 * Hash algorithm OIDs plus ASN.1 DER wrappings [RFC4880 sec 5.2.2].
22 static const u8 rsa_digest_info_md5[] = {
23 0x30, 0x20, 0x30, 0x0c, 0x06, 0x08,
24 0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x02, 0x05, /* OID */
25 0x05, 0x00, 0x04, 0x10
28 static const u8 rsa_digest_info_sha1[] = {
29 0x30, 0x21, 0x30, 0x09, 0x06, 0x05,
30 0x2b, 0x0e, 0x03, 0x02, 0x1a,
31 0x05, 0x00, 0x04, 0x14
34 static const u8 rsa_digest_info_rmd160[] = {
35 0x30, 0x21, 0x30, 0x09, 0x06, 0x05,
36 0x2b, 0x24, 0x03, 0x02, 0x01,
37 0x05, 0x00, 0x04, 0x14
40 static const u8 rsa_digest_info_sha224[] = {
41 0x30, 0x2d, 0x30, 0x0d, 0x06, 0x09,
42 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x04,
43 0x05, 0x00, 0x04, 0x1c
46 static const u8 rsa_digest_info_sha256[] = {
47 0x30, 0x31, 0x30, 0x0d, 0x06, 0x09,
48 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x01,
49 0x05, 0x00, 0x04, 0x20
52 static const u8 rsa_digest_info_sha384[] = {
53 0x30, 0x41, 0x30, 0x0d, 0x06, 0x09,
54 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x02,
55 0x05, 0x00, 0x04, 0x30
58 static const u8 rsa_digest_info_sha512[] = {
59 0x30, 0x51, 0x30, 0x0d, 0x06, 0x09,
60 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x03,
61 0x05, 0x00, 0x04, 0x40
64 static const u8 rsa_digest_info_sha3_256[] = {
65 0x30, 0x31, 0x30, 0x0d, 0x06, 0x09,
66 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x08,
67 0x05, 0x00, 0x04, 0x20
70 static const u8 rsa_digest_info_sha3_384[] = {
71 0x30, 0x41, 0x30, 0x0d, 0x06, 0x09,
72 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x09,
73 0x05, 0x00, 0x04, 0x30
76 static const u8 rsa_digest_info_sha3_512[] = {
77 0x30, 0x51, 0x30, 0x0d, 0x06, 0x09,
78 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x0A,
79 0x05, 0x00, 0x04, 0x40
82 static const struct rsa_asn1_template {
86 } rsa_asn1_templates[] = {
87 #define _(X) { #X, rsa_digest_info_##X, sizeof(rsa_digest_info_##X) }
96 #define _(X) { "sha3-" #X, rsa_digest_info_sha3_##X, sizeof(rsa_digest_info_sha3_##X) }
104 static const struct rsa_asn1_template *rsa_lookup_asn1(const char *name)
106 const struct rsa_asn1_template *p;
108 for (p = rsa_asn1_templates; p->name; p++)
109 if (strcmp(name, p->name) == 0)
114 struct pkcs1pad_ctx {
115 struct crypto_akcipher *child;
116 unsigned int key_size;
119 struct pkcs1pad_inst_ctx {
120 struct crypto_akcipher_spawn spawn;
121 const struct rsa_asn1_template *digest_info;
124 struct pkcs1pad_request {
125 struct scatterlist in_sg[2], out_sg[1];
126 uint8_t *in_buf, *out_buf;
127 struct akcipher_request child_req;
130 static int pkcs1pad_set_pub_key(struct crypto_akcipher *tfm, const void *key,
133 struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
138 err = crypto_akcipher_set_pub_key(ctx->child, key, keylen);
142 /* Find out new modulus size from rsa implementation */
143 err = crypto_akcipher_maxsize(ctx->child);
151 static int pkcs1pad_set_priv_key(struct crypto_akcipher *tfm, const void *key,
154 struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
159 err = crypto_akcipher_set_priv_key(ctx->child, key, keylen);
163 /* Find out new modulus size from rsa implementation */
164 err = crypto_akcipher_maxsize(ctx->child);
172 static unsigned int pkcs1pad_get_max_size(struct crypto_akcipher *tfm)
174 struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
177 * The maximum destination buffer size for the encrypt/sign operations
178 * will be the same as for RSA, even though it's smaller for
182 return ctx->key_size;
185 static void pkcs1pad_sg_set_buf(struct scatterlist *sg, void *buf, size_t len,
186 struct scatterlist *next)
188 int nsegs = next ? 2 : 1;
190 sg_init_table(sg, nsegs);
191 sg_set_buf(sg, buf, len);
194 sg_chain(sg, nsegs, next);
197 static int pkcs1pad_encrypt_sign_complete(struct akcipher_request *req, int err)
199 struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
200 struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
201 struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
202 unsigned int pad_len;
209 len = req_ctx->child_req.dst_len;
210 pad_len = ctx->key_size - len;
212 /* Four billion to one */
213 if (likely(!pad_len))
216 out_buf = kzalloc(ctx->key_size, GFP_ATOMIC);
221 sg_copy_to_buffer(req->dst, sg_nents_for_len(req->dst, len),
222 out_buf + pad_len, len);
223 sg_copy_from_buffer(req->dst,
224 sg_nents_for_len(req->dst, ctx->key_size),
225 out_buf, ctx->key_size);
226 kfree_sensitive(out_buf);
229 req->dst_len = ctx->key_size;
231 kfree(req_ctx->in_buf);
236 static void pkcs1pad_encrypt_sign_complete_cb(void *data, int err)
238 struct akcipher_request *req = data;
240 if (err == -EINPROGRESS)
243 err = pkcs1pad_encrypt_sign_complete(req, err);
246 akcipher_request_complete(req, err);
249 static int pkcs1pad_encrypt(struct akcipher_request *req)
251 struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
252 struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
253 struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
255 unsigned int i, ps_end;
260 if (req->src_len > ctx->key_size - 11)
263 if (req->dst_len < ctx->key_size) {
264 req->dst_len = ctx->key_size;
268 req_ctx->in_buf = kmalloc(ctx->key_size - 1 - req->src_len,
270 if (!req_ctx->in_buf)
273 ps_end = ctx->key_size - req->src_len - 2;
274 req_ctx->in_buf[0] = 0x02;
275 for (i = 1; i < ps_end; i++)
276 req_ctx->in_buf[i] = get_random_u32_inclusive(1, 255);
277 req_ctx->in_buf[ps_end] = 0x00;
279 pkcs1pad_sg_set_buf(req_ctx->in_sg, req_ctx->in_buf,
280 ctx->key_size - 1 - req->src_len, req->src);
282 akcipher_request_set_tfm(&req_ctx->child_req, ctx->child);
283 akcipher_request_set_callback(&req_ctx->child_req, req->base.flags,
284 pkcs1pad_encrypt_sign_complete_cb, req);
286 /* Reuse output buffer */
287 akcipher_request_set_crypt(&req_ctx->child_req, req_ctx->in_sg,
288 req->dst, ctx->key_size - 1, req->dst_len);
290 err = crypto_akcipher_encrypt(&req_ctx->child_req);
291 if (err != -EINPROGRESS && err != -EBUSY)
292 return pkcs1pad_encrypt_sign_complete(req, err);
297 static int pkcs1pad_decrypt_complete(struct akcipher_request *req, int err)
299 struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
300 struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
301 struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
302 unsigned int dst_len;
310 dst_len = req_ctx->child_req.dst_len;
311 if (dst_len < ctx->key_size - 1)
314 out_buf = req_ctx->out_buf;
315 if (dst_len == ctx->key_size) {
316 if (out_buf[0] != 0x00)
317 /* Decrypted value had no leading 0 byte */
324 if (out_buf[0] != 0x02)
327 for (pos = 1; pos < dst_len; pos++)
328 if (out_buf[pos] == 0x00)
330 if (pos < 9 || pos == dst_len)
336 if (req->dst_len < dst_len - pos)
338 req->dst_len = dst_len - pos;
341 sg_copy_from_buffer(req->dst,
342 sg_nents_for_len(req->dst, req->dst_len),
343 out_buf + pos, req->dst_len);
346 kfree_sensitive(req_ctx->out_buf);
351 static void pkcs1pad_decrypt_complete_cb(void *data, int err)
353 struct akcipher_request *req = data;
355 if (err == -EINPROGRESS)
358 err = pkcs1pad_decrypt_complete(req, err);
361 akcipher_request_complete(req, err);
364 static int pkcs1pad_decrypt(struct akcipher_request *req)
366 struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
367 struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
368 struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
371 if (!ctx->key_size || req->src_len != ctx->key_size)
374 req_ctx->out_buf = kmalloc(ctx->key_size, GFP_KERNEL);
375 if (!req_ctx->out_buf)
378 pkcs1pad_sg_set_buf(req_ctx->out_sg, req_ctx->out_buf,
379 ctx->key_size, NULL);
381 akcipher_request_set_tfm(&req_ctx->child_req, ctx->child);
382 akcipher_request_set_callback(&req_ctx->child_req, req->base.flags,
383 pkcs1pad_decrypt_complete_cb, req);
385 /* Reuse input buffer, output to a new buffer */
386 akcipher_request_set_crypt(&req_ctx->child_req, req->src,
387 req_ctx->out_sg, req->src_len,
390 err = crypto_akcipher_decrypt(&req_ctx->child_req);
391 if (err != -EINPROGRESS && err != -EBUSY)
392 return pkcs1pad_decrypt_complete(req, err);
397 static int pkcs1pad_sign(struct akcipher_request *req)
399 struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
400 struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
401 struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
402 struct akcipher_instance *inst = akcipher_alg_instance(tfm);
403 struct pkcs1pad_inst_ctx *ictx = akcipher_instance_ctx(inst);
404 const struct rsa_asn1_template *digest_info = ictx->digest_info;
406 unsigned int ps_end, digest_info_size = 0;
412 digest_info_size = digest_info->size;
414 if (req->src_len + digest_info_size > ctx->key_size - 11)
417 if (req->dst_len < ctx->key_size) {
418 req->dst_len = ctx->key_size;
422 req_ctx->in_buf = kmalloc(ctx->key_size - 1 - req->src_len,
424 if (!req_ctx->in_buf)
427 ps_end = ctx->key_size - digest_info_size - req->src_len - 2;
428 req_ctx->in_buf[0] = 0x01;
429 memset(req_ctx->in_buf + 1, 0xff, ps_end - 1);
430 req_ctx->in_buf[ps_end] = 0x00;
433 memcpy(req_ctx->in_buf + ps_end + 1, digest_info->data,
436 pkcs1pad_sg_set_buf(req_ctx->in_sg, req_ctx->in_buf,
437 ctx->key_size - 1 - req->src_len, req->src);
439 akcipher_request_set_tfm(&req_ctx->child_req, ctx->child);
440 akcipher_request_set_callback(&req_ctx->child_req, req->base.flags,
441 pkcs1pad_encrypt_sign_complete_cb, req);
443 /* Reuse output buffer */
444 akcipher_request_set_crypt(&req_ctx->child_req, req_ctx->in_sg,
445 req->dst, ctx->key_size - 1, req->dst_len);
447 err = crypto_akcipher_decrypt(&req_ctx->child_req);
448 if (err != -EINPROGRESS && err != -EBUSY)
449 return pkcs1pad_encrypt_sign_complete(req, err);
454 static int pkcs1pad_verify_complete(struct akcipher_request *req, int err)
456 struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
457 struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
458 struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
459 struct akcipher_instance *inst = akcipher_alg_instance(tfm);
460 struct pkcs1pad_inst_ctx *ictx = akcipher_instance_ctx(inst);
461 const struct rsa_asn1_template *digest_info = ictx->digest_info;
462 const unsigned int sig_size = req->src_len;
463 const unsigned int digest_size = req->dst_len;
464 unsigned int dst_len;
472 dst_len = req_ctx->child_req.dst_len;
473 if (dst_len < ctx->key_size - 1)
476 out_buf = req_ctx->out_buf;
477 if (dst_len == ctx->key_size) {
478 if (out_buf[0] != 0x00)
479 /* Decrypted value had no leading 0 byte */
487 if (out_buf[0] != 0x01)
490 for (pos = 1; pos < dst_len; pos++)
491 if (out_buf[pos] != 0xff)
494 if (pos < 9 || pos == dst_len || out_buf[pos] != 0x00)
499 if (digest_info->size > dst_len - pos)
501 if (crypto_memneq(out_buf + pos, digest_info->data,
505 pos += digest_info->size;
510 if (digest_size != dst_len - pos) {
512 req->dst_len = dst_len - pos;
515 /* Extract appended digest. */
516 sg_pcopy_to_buffer(req->src,
517 sg_nents_for_len(req->src, sig_size + digest_size),
518 req_ctx->out_buf + ctx->key_size,
519 digest_size, sig_size);
520 /* Do the actual verification step. */
521 if (memcmp(req_ctx->out_buf + ctx->key_size, out_buf + pos,
525 kfree_sensitive(req_ctx->out_buf);
530 static void pkcs1pad_verify_complete_cb(void *data, int err)
532 struct akcipher_request *req = data;
534 if (err == -EINPROGRESS)
537 err = pkcs1pad_verify_complete(req, err);
540 akcipher_request_complete(req, err);
544 * The verify operation is here for completeness similar to the verification
545 * defined in RFC2313 section 10.2 except that block type 0 is not accepted,
546 * as in RFC2437. RFC2437 section 9.2 doesn't define any operation to
547 * retrieve the DigestInfo from a signature, instead the user is expected
548 * to call the sign operation to generate the expected signature and compare
549 * signatures instead of the message-digests.
551 static int pkcs1pad_verify(struct akcipher_request *req)
553 struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
554 struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
555 struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
556 const unsigned int sig_size = req->src_len;
557 const unsigned int digest_size = req->dst_len;
560 if (WARN_ON(req->dst) || WARN_ON(!digest_size) ||
561 !ctx->key_size || sig_size != ctx->key_size)
564 req_ctx->out_buf = kmalloc(ctx->key_size + digest_size, GFP_KERNEL);
565 if (!req_ctx->out_buf)
568 pkcs1pad_sg_set_buf(req_ctx->out_sg, req_ctx->out_buf,
569 ctx->key_size, NULL);
571 akcipher_request_set_tfm(&req_ctx->child_req, ctx->child);
572 akcipher_request_set_callback(&req_ctx->child_req, req->base.flags,
573 pkcs1pad_verify_complete_cb, req);
575 /* Reuse input buffer, output to a new buffer */
576 akcipher_request_set_crypt(&req_ctx->child_req, req->src,
577 req_ctx->out_sg, sig_size, ctx->key_size);
579 err = crypto_akcipher_encrypt(&req_ctx->child_req);
580 if (err != -EINPROGRESS && err != -EBUSY)
581 return pkcs1pad_verify_complete(req, err);
586 static int pkcs1pad_init_tfm(struct crypto_akcipher *tfm)
588 struct akcipher_instance *inst = akcipher_alg_instance(tfm);
589 struct pkcs1pad_inst_ctx *ictx = akcipher_instance_ctx(inst);
590 struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
591 struct crypto_akcipher *child_tfm;
593 child_tfm = crypto_spawn_akcipher(&ictx->spawn);
594 if (IS_ERR(child_tfm))
595 return PTR_ERR(child_tfm);
597 ctx->child = child_tfm;
599 akcipher_set_reqsize(tfm, sizeof(struct pkcs1pad_request) +
600 crypto_akcipher_reqsize(child_tfm));
605 static void pkcs1pad_exit_tfm(struct crypto_akcipher *tfm)
607 struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
609 crypto_free_akcipher(ctx->child);
612 static void pkcs1pad_free(struct akcipher_instance *inst)
614 struct pkcs1pad_inst_ctx *ctx = akcipher_instance_ctx(inst);
615 struct crypto_akcipher_spawn *spawn = &ctx->spawn;
617 crypto_drop_akcipher(spawn);
621 static int pkcs1pad_create(struct crypto_template *tmpl, struct rtattr **tb)
624 struct akcipher_instance *inst;
625 struct pkcs1pad_inst_ctx *ctx;
626 struct akcipher_alg *rsa_alg;
627 const char *hash_name;
630 err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_AKCIPHER, &mask);
634 inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
638 ctx = akcipher_instance_ctx(inst);
640 err = crypto_grab_akcipher(&ctx->spawn, akcipher_crypto_instance(inst),
641 crypto_attr_alg_name(tb[1]), 0, mask);
645 rsa_alg = crypto_spawn_akcipher_alg(&ctx->spawn);
647 if (strcmp(rsa_alg->base.cra_name, "rsa") != 0) {
653 hash_name = crypto_attr_alg_name(tb[2]);
654 if (IS_ERR(hash_name)) {
655 if (snprintf(inst->alg.base.cra_name,
656 CRYPTO_MAX_ALG_NAME, "pkcs1pad(%s)",
657 rsa_alg->base.cra_name) >= CRYPTO_MAX_ALG_NAME)
660 if (snprintf(inst->alg.base.cra_driver_name,
661 CRYPTO_MAX_ALG_NAME, "pkcs1pad(%s)",
662 rsa_alg->base.cra_driver_name) >=
666 ctx->digest_info = rsa_lookup_asn1(hash_name);
667 if (!ctx->digest_info) {
672 if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
673 "pkcs1pad(%s,%s)", rsa_alg->base.cra_name,
674 hash_name) >= CRYPTO_MAX_ALG_NAME)
677 if (snprintf(inst->alg.base.cra_driver_name,
678 CRYPTO_MAX_ALG_NAME, "pkcs1pad(%s,%s)",
679 rsa_alg->base.cra_driver_name,
680 hash_name) >= CRYPTO_MAX_ALG_NAME)
684 inst->alg.base.cra_priority = rsa_alg->base.cra_priority;
685 inst->alg.base.cra_ctxsize = sizeof(struct pkcs1pad_ctx);
687 inst->alg.init = pkcs1pad_init_tfm;
688 inst->alg.exit = pkcs1pad_exit_tfm;
690 inst->alg.encrypt = pkcs1pad_encrypt;
691 inst->alg.decrypt = pkcs1pad_decrypt;
692 inst->alg.sign = pkcs1pad_sign;
693 inst->alg.verify = pkcs1pad_verify;
694 inst->alg.set_pub_key = pkcs1pad_set_pub_key;
695 inst->alg.set_priv_key = pkcs1pad_set_priv_key;
696 inst->alg.max_size = pkcs1pad_get_max_size;
698 inst->free = pkcs1pad_free;
700 err = akcipher_register_instance(tmpl, inst);
708 struct crypto_template rsa_pkcs1pad_tmpl = {
710 .create = pkcs1pad_create,
711 .module = THIS_MODULE,
714 MODULE_ALIAS_CRYPTO("pkcs1pad");