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 struct rsa_asn1_template {
68 } rsa_asn1_templates[] = {
69 #define _(X) { #X, rsa_digest_info_##X, sizeof(rsa_digest_info_##X) }
81 static const struct rsa_asn1_template *rsa_lookup_asn1(const char *name)
83 const struct rsa_asn1_template *p;
85 for (p = rsa_asn1_templates; p->name; p++)
86 if (strcmp(name, p->name) == 0)
92 struct crypto_akcipher *child;
93 unsigned int key_size;
96 struct pkcs1pad_inst_ctx {
97 struct crypto_akcipher_spawn spawn;
98 const struct rsa_asn1_template *digest_info;
101 struct pkcs1pad_request {
102 struct scatterlist in_sg[2], out_sg[1];
103 uint8_t *in_buf, *out_buf;
104 struct akcipher_request child_req;
107 static int pkcs1pad_set_pub_key(struct crypto_akcipher *tfm, const void *key,
110 struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
115 err = crypto_akcipher_set_pub_key(ctx->child, key, keylen);
119 /* Find out new modulus size from rsa implementation */
120 err = crypto_akcipher_maxsize(ctx->child);
128 static int pkcs1pad_set_priv_key(struct crypto_akcipher *tfm, const void *key,
131 struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
136 err = crypto_akcipher_set_priv_key(ctx->child, key, keylen);
140 /* Find out new modulus size from rsa implementation */
141 err = crypto_akcipher_maxsize(ctx->child);
149 static unsigned int pkcs1pad_get_max_size(struct crypto_akcipher *tfm)
151 struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
154 * The maximum destination buffer size for the encrypt/sign operations
155 * will be the same as for RSA, even though it's smaller for
159 return ctx->key_size;
162 static void pkcs1pad_sg_set_buf(struct scatterlist *sg, void *buf, size_t len,
163 struct scatterlist *next)
165 int nsegs = next ? 2 : 1;
167 sg_init_table(sg, nsegs);
168 sg_set_buf(sg, buf, len);
171 sg_chain(sg, nsegs, next);
174 static int pkcs1pad_encrypt_sign_complete(struct akcipher_request *req, int err)
176 struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
177 struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
178 struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
179 unsigned int pad_len;
186 len = req_ctx->child_req.dst_len;
187 pad_len = ctx->key_size - len;
189 /* Four billion to one */
190 if (likely(!pad_len))
193 out_buf = kzalloc(ctx->key_size, GFP_KERNEL);
198 sg_copy_to_buffer(req->dst, sg_nents_for_len(req->dst, len),
199 out_buf + pad_len, len);
200 sg_copy_from_buffer(req->dst,
201 sg_nents_for_len(req->dst, ctx->key_size),
202 out_buf, ctx->key_size);
203 kfree_sensitive(out_buf);
206 req->dst_len = ctx->key_size;
208 kfree(req_ctx->in_buf);
213 static void pkcs1pad_encrypt_sign_complete_cb(
214 struct crypto_async_request *child_async_req, int err)
216 struct akcipher_request *req = child_async_req->data;
217 struct crypto_async_request async_req;
219 if (err == -EINPROGRESS)
222 async_req.data = req->base.data;
223 async_req.tfm = crypto_akcipher_tfm(crypto_akcipher_reqtfm(req));
224 async_req.flags = child_async_req->flags;
225 req->base.complete(&async_req,
226 pkcs1pad_encrypt_sign_complete(req, err));
229 static int pkcs1pad_encrypt(struct akcipher_request *req)
231 struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
232 struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
233 struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
235 unsigned int i, ps_end;
240 if (req->src_len > ctx->key_size - 11)
243 if (req->dst_len < ctx->key_size) {
244 req->dst_len = ctx->key_size;
248 req_ctx->in_buf = kmalloc(ctx->key_size - 1 - req->src_len,
250 if (!req_ctx->in_buf)
253 ps_end = ctx->key_size - req->src_len - 2;
254 req_ctx->in_buf[0] = 0x02;
255 for (i = 1; i < ps_end; i++)
256 req_ctx->in_buf[i] = 1 + prandom_u32_max(255);
257 req_ctx->in_buf[ps_end] = 0x00;
259 pkcs1pad_sg_set_buf(req_ctx->in_sg, req_ctx->in_buf,
260 ctx->key_size - 1 - req->src_len, req->src);
262 akcipher_request_set_tfm(&req_ctx->child_req, ctx->child);
263 akcipher_request_set_callback(&req_ctx->child_req, req->base.flags,
264 pkcs1pad_encrypt_sign_complete_cb, req);
266 /* Reuse output buffer */
267 akcipher_request_set_crypt(&req_ctx->child_req, req_ctx->in_sg,
268 req->dst, ctx->key_size - 1, req->dst_len);
270 err = crypto_akcipher_encrypt(&req_ctx->child_req);
271 if (err != -EINPROGRESS && err != -EBUSY)
272 return pkcs1pad_encrypt_sign_complete(req, err);
277 static int pkcs1pad_decrypt_complete(struct akcipher_request *req, int err)
279 struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
280 struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
281 struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
282 unsigned int dst_len;
290 dst_len = req_ctx->child_req.dst_len;
291 if (dst_len < ctx->key_size - 1)
294 out_buf = req_ctx->out_buf;
295 if (dst_len == ctx->key_size) {
296 if (out_buf[0] != 0x00)
297 /* Decrypted value had no leading 0 byte */
304 if (out_buf[0] != 0x02)
307 for (pos = 1; pos < dst_len; pos++)
308 if (out_buf[pos] == 0x00)
310 if (pos < 9 || pos == dst_len)
316 if (req->dst_len < dst_len - pos)
318 req->dst_len = dst_len - pos;
321 sg_copy_from_buffer(req->dst,
322 sg_nents_for_len(req->dst, req->dst_len),
323 out_buf + pos, req->dst_len);
326 kfree_sensitive(req_ctx->out_buf);
331 static void pkcs1pad_decrypt_complete_cb(
332 struct crypto_async_request *child_async_req, int err)
334 struct akcipher_request *req = child_async_req->data;
335 struct crypto_async_request async_req;
337 if (err == -EINPROGRESS)
340 async_req.data = req->base.data;
341 async_req.tfm = crypto_akcipher_tfm(crypto_akcipher_reqtfm(req));
342 async_req.flags = child_async_req->flags;
343 req->base.complete(&async_req, pkcs1pad_decrypt_complete(req, err));
346 static int pkcs1pad_decrypt(struct akcipher_request *req)
348 struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
349 struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
350 struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
353 if (!ctx->key_size || req->src_len != ctx->key_size)
356 req_ctx->out_buf = kmalloc(ctx->key_size, GFP_KERNEL);
357 if (!req_ctx->out_buf)
360 pkcs1pad_sg_set_buf(req_ctx->out_sg, req_ctx->out_buf,
361 ctx->key_size, NULL);
363 akcipher_request_set_tfm(&req_ctx->child_req, ctx->child);
364 akcipher_request_set_callback(&req_ctx->child_req, req->base.flags,
365 pkcs1pad_decrypt_complete_cb, req);
367 /* Reuse input buffer, output to a new buffer */
368 akcipher_request_set_crypt(&req_ctx->child_req, req->src,
369 req_ctx->out_sg, req->src_len,
372 err = crypto_akcipher_decrypt(&req_ctx->child_req);
373 if (err != -EINPROGRESS && err != -EBUSY)
374 return pkcs1pad_decrypt_complete(req, err);
379 static int pkcs1pad_sign(struct akcipher_request *req)
381 struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
382 struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
383 struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
384 struct akcipher_instance *inst = akcipher_alg_instance(tfm);
385 struct pkcs1pad_inst_ctx *ictx = akcipher_instance_ctx(inst);
386 const struct rsa_asn1_template *digest_info = ictx->digest_info;
388 unsigned int ps_end, digest_size = 0;
394 digest_size = digest_info->size;
396 if (req->src_len + digest_size > ctx->key_size - 11)
399 if (req->dst_len < ctx->key_size) {
400 req->dst_len = ctx->key_size;
404 req_ctx->in_buf = kmalloc(ctx->key_size - 1 - req->src_len,
406 if (!req_ctx->in_buf)
409 ps_end = ctx->key_size - digest_size - req->src_len - 2;
410 req_ctx->in_buf[0] = 0x01;
411 memset(req_ctx->in_buf + 1, 0xff, ps_end - 1);
412 req_ctx->in_buf[ps_end] = 0x00;
415 memcpy(req_ctx->in_buf + ps_end + 1, digest_info->data,
418 pkcs1pad_sg_set_buf(req_ctx->in_sg, req_ctx->in_buf,
419 ctx->key_size - 1 - req->src_len, req->src);
421 akcipher_request_set_tfm(&req_ctx->child_req, ctx->child);
422 akcipher_request_set_callback(&req_ctx->child_req, req->base.flags,
423 pkcs1pad_encrypt_sign_complete_cb, req);
425 /* Reuse output buffer */
426 akcipher_request_set_crypt(&req_ctx->child_req, req_ctx->in_sg,
427 req->dst, ctx->key_size - 1, req->dst_len);
429 err = crypto_akcipher_decrypt(&req_ctx->child_req);
430 if (err != -EINPROGRESS && err != -EBUSY)
431 return pkcs1pad_encrypt_sign_complete(req, err);
436 static int pkcs1pad_verify_complete(struct akcipher_request *req, int err)
438 struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
439 struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
440 struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
441 struct akcipher_instance *inst = akcipher_alg_instance(tfm);
442 struct pkcs1pad_inst_ctx *ictx = akcipher_instance_ctx(inst);
443 const struct rsa_asn1_template *digest_info = ictx->digest_info;
444 unsigned int dst_len;
452 dst_len = req_ctx->child_req.dst_len;
453 if (dst_len < ctx->key_size - 1)
456 out_buf = req_ctx->out_buf;
457 if (dst_len == ctx->key_size) {
458 if (out_buf[0] != 0x00)
459 /* Decrypted value had no leading 0 byte */
467 if (out_buf[0] != 0x01)
470 for (pos = 1; pos < dst_len; pos++)
471 if (out_buf[pos] != 0xff)
474 if (pos < 9 || pos == dst_len || out_buf[pos] != 0x00)
479 if (crypto_memneq(out_buf + pos, digest_info->data,
483 pos += digest_info->size;
488 if (req->dst_len != dst_len - pos) {
490 req->dst_len = dst_len - pos;
493 /* Extract appended digest. */
494 sg_pcopy_to_buffer(req->src,
495 sg_nents_for_len(req->src,
496 req->src_len + req->dst_len),
497 req_ctx->out_buf + ctx->key_size,
498 req->dst_len, ctx->key_size);
499 /* Do the actual verification step. */
500 if (memcmp(req_ctx->out_buf + ctx->key_size, out_buf + pos,
504 kfree_sensitive(req_ctx->out_buf);
509 static void pkcs1pad_verify_complete_cb(
510 struct crypto_async_request *child_async_req, int err)
512 struct akcipher_request *req = child_async_req->data;
513 struct crypto_async_request async_req;
515 if (err == -EINPROGRESS)
518 async_req.data = req->base.data;
519 async_req.tfm = crypto_akcipher_tfm(crypto_akcipher_reqtfm(req));
520 async_req.flags = child_async_req->flags;
521 req->base.complete(&async_req, pkcs1pad_verify_complete(req, err));
525 * The verify operation is here for completeness similar to the verification
526 * defined in RFC2313 section 10.2 except that block type 0 is not accepted,
527 * as in RFC2437. RFC2437 section 9.2 doesn't define any operation to
528 * retrieve the DigestInfo from a signature, instead the user is expected
529 * to call the sign operation to generate the expected signature and compare
530 * signatures instead of the message-digests.
532 static int pkcs1pad_verify(struct akcipher_request *req)
534 struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
535 struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
536 struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
539 if (WARN_ON(req->dst) ||
540 WARN_ON(!req->dst_len) ||
541 !ctx->key_size || req->src_len < ctx->key_size)
544 req_ctx->out_buf = kmalloc(ctx->key_size + req->dst_len, GFP_KERNEL);
545 if (!req_ctx->out_buf)
548 pkcs1pad_sg_set_buf(req_ctx->out_sg, req_ctx->out_buf,
549 ctx->key_size, NULL);
551 akcipher_request_set_tfm(&req_ctx->child_req, ctx->child);
552 akcipher_request_set_callback(&req_ctx->child_req, req->base.flags,
553 pkcs1pad_verify_complete_cb, req);
555 /* Reuse input buffer, output to a new buffer */
556 akcipher_request_set_crypt(&req_ctx->child_req, req->src,
557 req_ctx->out_sg, req->src_len,
560 err = crypto_akcipher_encrypt(&req_ctx->child_req);
561 if (err != -EINPROGRESS && err != -EBUSY)
562 return pkcs1pad_verify_complete(req, err);
567 static int pkcs1pad_init_tfm(struct crypto_akcipher *tfm)
569 struct akcipher_instance *inst = akcipher_alg_instance(tfm);
570 struct pkcs1pad_inst_ctx *ictx = akcipher_instance_ctx(inst);
571 struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
572 struct crypto_akcipher *child_tfm;
574 child_tfm = crypto_spawn_akcipher(&ictx->spawn);
575 if (IS_ERR(child_tfm))
576 return PTR_ERR(child_tfm);
578 ctx->child = child_tfm;
582 static void pkcs1pad_exit_tfm(struct crypto_akcipher *tfm)
584 struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
586 crypto_free_akcipher(ctx->child);
589 static void pkcs1pad_free(struct akcipher_instance *inst)
591 struct pkcs1pad_inst_ctx *ctx = akcipher_instance_ctx(inst);
592 struct crypto_akcipher_spawn *spawn = &ctx->spawn;
594 crypto_drop_akcipher(spawn);
598 static int pkcs1pad_create(struct crypto_template *tmpl, struct rtattr **tb)
601 struct akcipher_instance *inst;
602 struct pkcs1pad_inst_ctx *ctx;
603 struct akcipher_alg *rsa_alg;
604 const char *hash_name;
607 err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_AKCIPHER, &mask);
611 inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
615 ctx = akcipher_instance_ctx(inst);
617 err = crypto_grab_akcipher(&ctx->spawn, akcipher_crypto_instance(inst),
618 crypto_attr_alg_name(tb[1]), 0, mask);
622 rsa_alg = crypto_spawn_akcipher_alg(&ctx->spawn);
625 hash_name = crypto_attr_alg_name(tb[2]);
626 if (IS_ERR(hash_name)) {
627 if (snprintf(inst->alg.base.cra_name,
628 CRYPTO_MAX_ALG_NAME, "pkcs1pad(%s)",
629 rsa_alg->base.cra_name) >= CRYPTO_MAX_ALG_NAME)
632 if (snprintf(inst->alg.base.cra_driver_name,
633 CRYPTO_MAX_ALG_NAME, "pkcs1pad(%s)",
634 rsa_alg->base.cra_driver_name) >=
638 ctx->digest_info = rsa_lookup_asn1(hash_name);
639 if (!ctx->digest_info) {
644 if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
645 "pkcs1pad(%s,%s)", rsa_alg->base.cra_name,
646 hash_name) >= CRYPTO_MAX_ALG_NAME)
649 if (snprintf(inst->alg.base.cra_driver_name,
650 CRYPTO_MAX_ALG_NAME, "pkcs1pad(%s,%s)",
651 rsa_alg->base.cra_driver_name,
652 hash_name) >= CRYPTO_MAX_ALG_NAME)
656 inst->alg.base.cra_priority = rsa_alg->base.cra_priority;
657 inst->alg.base.cra_ctxsize = sizeof(struct pkcs1pad_ctx);
659 inst->alg.init = pkcs1pad_init_tfm;
660 inst->alg.exit = pkcs1pad_exit_tfm;
662 inst->alg.encrypt = pkcs1pad_encrypt;
663 inst->alg.decrypt = pkcs1pad_decrypt;
664 inst->alg.sign = pkcs1pad_sign;
665 inst->alg.verify = pkcs1pad_verify;
666 inst->alg.set_pub_key = pkcs1pad_set_pub_key;
667 inst->alg.set_priv_key = pkcs1pad_set_priv_key;
668 inst->alg.max_size = pkcs1pad_get_max_size;
669 inst->alg.reqsize = sizeof(struct pkcs1pad_request) + rsa_alg->reqsize;
671 inst->free = pkcs1pad_free;
673 err = akcipher_register_instance(tmpl, inst);
681 struct crypto_template rsa_pkcs1pad_tmpl = {
683 .create = pkcs1pad_create,
684 .module = THIS_MODULE,