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 scatterlist in_sg[2], out_sg[1];
105 uint8_t *in_buf, *out_buf;
106 struct akcipher_request child_req;
109 static int pkcs1pad_set_pub_key(struct crypto_akcipher *tfm, const void *key,
112 struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
117 err = crypto_akcipher_set_pub_key(ctx->child, key, keylen);
121 /* Find out new modulus size from rsa implementation */
122 err = crypto_akcipher_maxsize(ctx->child);
130 static int pkcs1pad_set_priv_key(struct crypto_akcipher *tfm, const void *key,
133 struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
138 err = crypto_akcipher_set_priv_key(ctx->child, key, keylen);
142 /* Find out new modulus size from rsa implementation */
143 err = crypto_akcipher_maxsize(ctx->child);
151 static unsigned int pkcs1pad_get_max_size(struct crypto_akcipher *tfm)
153 struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
156 * The maximum destination buffer size for the encrypt/sign operations
157 * will be the same as for RSA, even though it's smaller for
161 return ctx->key_size;
164 static void pkcs1pad_sg_set_buf(struct scatterlist *sg, void *buf, size_t len,
165 struct scatterlist *next)
167 int nsegs = next ? 2 : 1;
169 sg_init_table(sg, nsegs);
170 sg_set_buf(sg, buf, len);
173 sg_chain(sg, nsegs, next);
176 static int pkcs1pad_encrypt_sign_complete(struct akcipher_request *req, int err)
178 struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
179 struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
180 struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
181 unsigned int pad_len;
188 len = req_ctx->child_req.dst_len;
189 pad_len = ctx->key_size - len;
191 /* Four billion to one */
192 if (likely(!pad_len))
195 out_buf = kzalloc(ctx->key_size, GFP_ATOMIC);
200 sg_copy_to_buffer(req->dst, sg_nents_for_len(req->dst, len),
201 out_buf + pad_len, len);
202 sg_copy_from_buffer(req->dst,
203 sg_nents_for_len(req->dst, ctx->key_size),
204 out_buf, ctx->key_size);
208 req->dst_len = ctx->key_size;
210 kfree(req_ctx->in_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 req_ctx->in_buf = kmalloc(ctx->key_size - 1 - req->src_len,
252 if (!req_ctx->in_buf)
255 ps_end = ctx->key_size - req->src_len - 2;
256 req_ctx->in_buf[0] = 0x02;
257 for (i = 1; i < ps_end; i++)
258 req_ctx->in_buf[i] = 1 + prandom_u32_max(255);
259 req_ctx->in_buf[ps_end] = 0x00;
261 pkcs1pad_sg_set_buf(req_ctx->in_sg, req_ctx->in_buf,
262 ctx->key_size - 1 - req->src_len, req->src);
264 akcipher_request_set_tfm(&req_ctx->child_req, ctx->child);
265 akcipher_request_set_callback(&req_ctx->child_req, req->base.flags,
266 pkcs1pad_encrypt_sign_complete_cb, req);
268 /* Reuse output buffer */
269 akcipher_request_set_crypt(&req_ctx->child_req, req_ctx->in_sg,
270 req->dst, ctx->key_size - 1, req->dst_len);
272 err = crypto_akcipher_encrypt(&req_ctx->child_req);
273 if (err != -EINPROGRESS &&
275 !(req->base.flags & CRYPTO_TFM_REQ_MAY_BACKLOG)))
276 return pkcs1pad_encrypt_sign_complete(req, err);
281 static int pkcs1pad_decrypt_complete(struct akcipher_request *req, int err)
283 struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
284 struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
285 struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
286 unsigned int dst_len;
294 dst_len = req_ctx->child_req.dst_len;
295 if (dst_len < ctx->key_size - 1)
298 out_buf = req_ctx->out_buf;
299 if (dst_len == ctx->key_size) {
300 if (out_buf[0] != 0x00)
301 /* Decrypted value had no leading 0 byte */
308 if (out_buf[0] != 0x02)
311 for (pos = 1; pos < dst_len; pos++)
312 if (out_buf[pos] == 0x00)
314 if (pos < 9 || pos == dst_len)
320 if (req->dst_len < dst_len - pos)
322 req->dst_len = dst_len - pos;
325 sg_copy_from_buffer(req->dst,
326 sg_nents_for_len(req->dst, req->dst_len),
327 out_buf + pos, req->dst_len);
330 kzfree(req_ctx->out_buf);
335 static void pkcs1pad_decrypt_complete_cb(
336 struct crypto_async_request *child_async_req, int err)
338 struct akcipher_request *req = child_async_req->data;
339 struct crypto_async_request async_req;
341 if (err == -EINPROGRESS)
344 async_req.data = req->base.data;
345 async_req.tfm = crypto_akcipher_tfm(crypto_akcipher_reqtfm(req));
346 async_req.flags = child_async_req->flags;
347 req->base.complete(&async_req, pkcs1pad_decrypt_complete(req, err));
350 static int pkcs1pad_decrypt(struct akcipher_request *req)
352 struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
353 struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
354 struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
357 if (!ctx->key_size || req->src_len != ctx->key_size)
360 req_ctx->out_buf = kmalloc(ctx->key_size, GFP_KERNEL);
361 if (!req_ctx->out_buf)
364 pkcs1pad_sg_set_buf(req_ctx->out_sg, req_ctx->out_buf,
365 ctx->key_size, NULL);
367 akcipher_request_set_tfm(&req_ctx->child_req, ctx->child);
368 akcipher_request_set_callback(&req_ctx->child_req, req->base.flags,
369 pkcs1pad_decrypt_complete_cb, req);
371 /* Reuse input buffer, output to a new buffer */
372 akcipher_request_set_crypt(&req_ctx->child_req, req->src,
373 req_ctx->out_sg, req->src_len,
376 err = crypto_akcipher_decrypt(&req_ctx->child_req);
377 if (err != -EINPROGRESS &&
379 !(req->base.flags & CRYPTO_TFM_REQ_MAY_BACKLOG)))
380 return pkcs1pad_decrypt_complete(req, err);
385 static int pkcs1pad_sign(struct akcipher_request *req)
387 struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
388 struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
389 struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
390 struct akcipher_instance *inst = akcipher_alg_instance(tfm);
391 struct pkcs1pad_inst_ctx *ictx = akcipher_instance_ctx(inst);
392 const struct rsa_asn1_template *digest_info = ictx->digest_info;
394 unsigned int ps_end, digest_size = 0;
399 digest_size = digest_info->size;
401 if (req->src_len + digest_size > ctx->key_size - 11)
404 if (req->dst_len < ctx->key_size) {
405 req->dst_len = ctx->key_size;
409 req_ctx->in_buf = kmalloc(ctx->key_size - 1 - req->src_len,
411 if (!req_ctx->in_buf)
414 ps_end = ctx->key_size - digest_size - req->src_len - 2;
415 req_ctx->in_buf[0] = 0x01;
416 memset(req_ctx->in_buf + 1, 0xff, ps_end - 1);
417 req_ctx->in_buf[ps_end] = 0x00;
419 memcpy(req_ctx->in_buf + ps_end + 1, digest_info->data,
422 pkcs1pad_sg_set_buf(req_ctx->in_sg, req_ctx->in_buf,
423 ctx->key_size - 1 - req->src_len, req->src);
425 akcipher_request_set_tfm(&req_ctx->child_req, ctx->child);
426 akcipher_request_set_callback(&req_ctx->child_req, req->base.flags,
427 pkcs1pad_encrypt_sign_complete_cb, req);
429 /* Reuse output buffer */
430 akcipher_request_set_crypt(&req_ctx->child_req, req_ctx->in_sg,
431 req->dst, ctx->key_size - 1, req->dst_len);
433 err = crypto_akcipher_sign(&req_ctx->child_req);
434 if (err != -EINPROGRESS &&
436 !(req->base.flags & CRYPTO_TFM_REQ_MAY_BACKLOG)))
437 return pkcs1pad_encrypt_sign_complete(req, err);
442 static int pkcs1pad_verify_complete(struct akcipher_request *req, int err)
444 struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
445 struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
446 struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
447 struct akcipher_instance *inst = akcipher_alg_instance(tfm);
448 struct pkcs1pad_inst_ctx *ictx = akcipher_instance_ctx(inst);
449 const struct rsa_asn1_template *digest_info = ictx->digest_info;
450 unsigned int dst_len;
458 dst_len = req_ctx->child_req.dst_len;
459 if (dst_len < ctx->key_size - 1)
462 out_buf = req_ctx->out_buf;
463 if (dst_len == ctx->key_size) {
464 if (out_buf[0] != 0x00)
465 /* Decrypted value had no leading 0 byte */
473 if (out_buf[0] != 0x01)
476 for (pos = 1; pos < dst_len; pos++)
477 if (out_buf[pos] != 0xff)
480 if (pos < 9 || pos == dst_len || out_buf[pos] != 0x00)
484 if (crypto_memneq(out_buf + pos, digest_info->data, digest_info->size))
487 pos += digest_info->size;
491 if (req->dst_len < dst_len - pos)
493 req->dst_len = dst_len - pos;
496 sg_copy_from_buffer(req->dst,
497 sg_nents_for_len(req->dst, req->dst_len),
498 out_buf + pos, req->dst_len);
500 kzfree(req_ctx->out_buf);
505 static void pkcs1pad_verify_complete_cb(
506 struct crypto_async_request *child_async_req, int err)
508 struct akcipher_request *req = child_async_req->data;
509 struct crypto_async_request async_req;
511 if (err == -EINPROGRESS)
514 async_req.data = req->base.data;
515 async_req.tfm = crypto_akcipher_tfm(crypto_akcipher_reqtfm(req));
516 async_req.flags = child_async_req->flags;
517 req->base.complete(&async_req, pkcs1pad_verify_complete(req, err));
521 * The verify operation is here for completeness similar to the verification
522 * defined in RFC2313 section 10.2 except that block type 0 is not accepted,
523 * as in RFC2437. RFC2437 section 9.2 doesn't define any operation to
524 * retrieve the DigestInfo from a signature, instead the user is expected
525 * to call the sign operation to generate the expected signature and compare
526 * signatures instead of the message-digests.
528 static int pkcs1pad_verify(struct akcipher_request *req)
530 struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
531 struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
532 struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
535 if (!ctx->key_size || req->src_len < ctx->key_size)
538 req_ctx->out_buf = kmalloc(ctx->key_size, GFP_KERNEL);
539 if (!req_ctx->out_buf)
542 pkcs1pad_sg_set_buf(req_ctx->out_sg, req_ctx->out_buf,
543 ctx->key_size, NULL);
545 akcipher_request_set_tfm(&req_ctx->child_req, ctx->child);
546 akcipher_request_set_callback(&req_ctx->child_req, req->base.flags,
547 pkcs1pad_verify_complete_cb, req);
549 /* Reuse input buffer, output to a new buffer */
550 akcipher_request_set_crypt(&req_ctx->child_req, req->src,
551 req_ctx->out_sg, req->src_len,
554 err = crypto_akcipher_verify(&req_ctx->child_req);
555 if (err != -EINPROGRESS &&
557 !(req->base.flags & CRYPTO_TFM_REQ_MAY_BACKLOG)))
558 return pkcs1pad_verify_complete(req, err);
563 static int pkcs1pad_init_tfm(struct crypto_akcipher *tfm)
565 struct akcipher_instance *inst = akcipher_alg_instance(tfm);
566 struct pkcs1pad_inst_ctx *ictx = akcipher_instance_ctx(inst);
567 struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
568 struct crypto_akcipher *child_tfm;
570 child_tfm = crypto_spawn_akcipher(&ictx->spawn);
571 if (IS_ERR(child_tfm))
572 return PTR_ERR(child_tfm);
574 ctx->child = child_tfm;
578 static void pkcs1pad_exit_tfm(struct crypto_akcipher *tfm)
580 struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
582 crypto_free_akcipher(ctx->child);
585 static void pkcs1pad_free(struct akcipher_instance *inst)
587 struct pkcs1pad_inst_ctx *ctx = akcipher_instance_ctx(inst);
588 struct crypto_akcipher_spawn *spawn = &ctx->spawn;
590 crypto_drop_akcipher(spawn);
594 static int pkcs1pad_create(struct crypto_template *tmpl, struct rtattr **tb)
596 const struct rsa_asn1_template *digest_info;
597 struct crypto_attr_type *algt;
598 struct akcipher_instance *inst;
599 struct pkcs1pad_inst_ctx *ctx;
600 struct crypto_akcipher_spawn *spawn;
601 struct akcipher_alg *rsa_alg;
602 const char *rsa_alg_name;
603 const char *hash_name;
606 algt = crypto_get_attr_type(tb);
608 return PTR_ERR(algt);
610 if ((algt->type ^ CRYPTO_ALG_TYPE_AKCIPHER) & algt->mask)
613 rsa_alg_name = crypto_attr_alg_name(tb[1]);
614 if (IS_ERR(rsa_alg_name))
615 return PTR_ERR(rsa_alg_name);
617 hash_name = crypto_attr_alg_name(tb[2]);
618 if (IS_ERR(hash_name))
619 return PTR_ERR(hash_name);
621 digest_info = rsa_lookup_asn1(hash_name);
625 inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
629 ctx = akcipher_instance_ctx(inst);
631 ctx->digest_info = digest_info;
633 crypto_set_spawn(&spawn->base, akcipher_crypto_instance(inst));
634 err = crypto_grab_akcipher(spawn, rsa_alg_name, 0,
635 crypto_requires_sync(algt->type, algt->mask));
639 rsa_alg = crypto_spawn_akcipher_alg(spawn);
643 if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
644 "pkcs1pad(%s,%s)", rsa_alg->base.cra_name, hash_name) >=
645 CRYPTO_MAX_ALG_NAME ||
646 snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
648 rsa_alg->base.cra_driver_name, hash_name) >=
652 inst->alg.base.cra_flags = rsa_alg->base.cra_flags & CRYPTO_ALG_ASYNC;
653 inst->alg.base.cra_priority = rsa_alg->base.cra_priority;
654 inst->alg.base.cra_ctxsize = sizeof(struct pkcs1pad_ctx);
656 inst->alg.init = pkcs1pad_init_tfm;
657 inst->alg.exit = pkcs1pad_exit_tfm;
659 inst->alg.encrypt = pkcs1pad_encrypt;
660 inst->alg.decrypt = pkcs1pad_decrypt;
661 inst->alg.sign = pkcs1pad_sign;
662 inst->alg.verify = pkcs1pad_verify;
663 inst->alg.set_pub_key = pkcs1pad_set_pub_key;
664 inst->alg.set_priv_key = pkcs1pad_set_priv_key;
665 inst->alg.max_size = pkcs1pad_get_max_size;
666 inst->alg.reqsize = sizeof(struct pkcs1pad_request) + rsa_alg->reqsize;
668 inst->free = pkcs1pad_free;
670 err = akcipher_register_instance(tmpl, inst);
677 crypto_drop_akcipher(spawn);
683 struct crypto_template rsa_pkcs1pad_tmpl = {
685 .create = pkcs1pad_create,
686 .module = THIS_MODULE,