#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/seq_file.h>
+#include <linux/scatterlist.h>
#include <keys/asymmetric-subtype.h>
#include <crypto/public_key.h>
+#include <crypto/akcipher.h>
MODULE_LICENSE("GPL");
};
EXPORT_SYMBOL_GPL(pkey_id_type_name);
-static int (*alg_verify[PKEY_ALGO__LAST])(const struct public_key *pkey,
- const struct public_key_signature *sig) = {
- NULL,
- rsa_verify_signature
-};
-
/*
* Provide a part of a description of the key for /proc/keys.
*/
}
EXPORT_SYMBOL_GPL(public_key_destroy);
+struct public_key_completion {
+ struct completion completion;
+ int err;
+};
+
+static void public_key_verify_done(struct crypto_async_request *req, int err)
+{
+ struct public_key_completion *compl = req->data;
+
+ if (err == -EINPROGRESS)
+ return;
+
+ compl->err = err;
+ complete(&compl->completion);
+}
+
/*
* Verify a signature using a public key.
*/
int public_key_verify_signature(const struct public_key *pkey,
const struct public_key_signature *sig)
{
+ struct public_key_completion compl;
+ struct crypto_akcipher *tfm;
+ struct akcipher_request *req;
+ struct scatterlist sig_sg, digest_sg;
+ const char *alg_name;
+ char alg_name_buf[CRYPTO_MAX_ALG_NAME];
+ void *output;
+ unsigned int outlen;
+ int ret = -ENOMEM;
+
+ pr_devel("==>%s()\n", __func__);
+
BUG_ON(!pkey);
BUG_ON(!sig);
BUG_ON(!sig->digest);
BUG_ON(!sig->s);
- if (pkey->pkey_algo >= PKEY_ALGO__LAST)
- return -ENOPKG;
+ alg_name = pkey_algo_name[sig->pkey_algo];
+ if (sig->pkey_algo == PKEY_ALGO_RSA) {
+ /* The data wangled by the RSA algorithm is typically padded
+ * and encoded in some manner, such as EMSA-PKCS1-1_5 [RFC3447
+ * sec 8.2].
+ */
+ if (snprintf(alg_name_buf, CRYPTO_MAX_ALG_NAME,
+ "pkcs1pad(rsa,%s)",
+ hash_algo_name[sig->pkey_hash_algo]
+ ) >= CRYPTO_MAX_ALG_NAME)
+ return -EINVAL;
+ alg_name = alg_name_buf;
+ }
+
+ tfm = crypto_alloc_akcipher(alg_name, 0, 0);
+ if (IS_ERR(tfm))
+ return PTR_ERR(tfm);
+
+ req = akcipher_request_alloc(tfm, GFP_KERNEL);
+ if (!req)
+ goto error_free_tfm;
+
+ ret = crypto_akcipher_set_pub_key(tfm, pkey->key, pkey->keylen);
+ if (ret)
+ goto error_free_req;
+
+ outlen = crypto_akcipher_maxsize(tfm);
+ output = kmalloc(outlen, GFP_KERNEL);
+ if (!output)
+ goto error_free_req;
+
+ sg_init_one(&sig_sg, sig->s, sig->s_size);
+ sg_init_one(&digest_sg, output, outlen);
+ akcipher_request_set_crypt(req, &sig_sg, &digest_sg, sig->s_size,
+ outlen);
+ init_completion(&compl.completion);
+ akcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG |
+ CRYPTO_TFM_REQ_MAY_SLEEP,
+ public_key_verify_done, &compl);
+
+ /* Perform the verification calculation. This doesn't actually do the
+ * verification, but rather calculates the hash expected by the
+ * signature and returns that to us.
+ */
+ ret = crypto_akcipher_verify(req);
+ if (ret == -EINPROGRESS) {
+ wait_for_completion(&compl.completion);
+ ret = compl.err;
+ }
+ if (ret < 0)
+ goto out_free_output;
- if (!alg_verify[pkey->pkey_algo])
- return -ENOPKG;
+ /* Do the actual verification step. */
+ if (req->dst_len != sig->digest_size ||
+ memcmp(sig->digest, output, sig->digest_size) != 0)
+ ret = -EKEYREJECTED;
- return alg_verify[pkey->pkey_algo](pkey, sig);
+out_free_output:
+ kfree(output);
+error_free_req:
+ akcipher_request_free(req);
+error_free_tfm:
+ crypto_free_akcipher(tfm);
+ pr_devel("<==%s() = %d\n", __func__, ret);
+ return ret;
}
EXPORT_SYMBOL_GPL(public_key_verify_signature);
+++ /dev/null
-/* RSA asymmetric public-key algorithm [RFC3447]
- *
- * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
- * Written by David Howells (dhowells@redhat.com)
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public Licence
- * as published by the Free Software Foundation; either version
- * 2 of the Licence, or (at your option) any later version.
- */
-
-#define pr_fmt(fmt) "RSA: "fmt
-#include <linux/module.h>
-#include <linux/slab.h>
-#include <crypto/akcipher.h>
-#include <crypto/public_key.h>
-#include <crypto/algapi.h>
-
-MODULE_LICENSE("GPL");
-MODULE_DESCRIPTION("RSA Public Key Algorithm");
-
-#define kenter(FMT, ...) \
- pr_devel("==> %s("FMT")\n", __func__, ##__VA_ARGS__)
-#define kleave(FMT, ...) \
- pr_devel("<== %s()"FMT"\n", __func__, ##__VA_ARGS__)
-
-/*
- * Hash algorithm OIDs plus ASN.1 DER wrappings [RFC4880 sec 5.2.2].
- */
-static const u8 RSA_digest_info_MD5[] = {
- 0x30, 0x20, 0x30, 0x0C, 0x06, 0x08,
- 0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x02, 0x05, /* OID */
- 0x05, 0x00, 0x04, 0x10
-};
-
-static const u8 RSA_digest_info_SHA1[] = {
- 0x30, 0x21, 0x30, 0x09, 0x06, 0x05,
- 0x2B, 0x0E, 0x03, 0x02, 0x1A,
- 0x05, 0x00, 0x04, 0x14
-};
-
-static const u8 RSA_digest_info_RIPE_MD_160[] = {
- 0x30, 0x21, 0x30, 0x09, 0x06, 0x05,
- 0x2B, 0x24, 0x03, 0x02, 0x01,
- 0x05, 0x00, 0x04, 0x14
-};
-
-static const u8 RSA_digest_info_SHA224[] = {
- 0x30, 0x2d, 0x30, 0x0d, 0x06, 0x09,
- 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x04,
- 0x05, 0x00, 0x04, 0x1C
-};
-
-static const u8 RSA_digest_info_SHA256[] = {
- 0x30, 0x31, 0x30, 0x0d, 0x06, 0x09,
- 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x01,
- 0x05, 0x00, 0x04, 0x20
-};
-
-static const u8 RSA_digest_info_SHA384[] = {
- 0x30, 0x41, 0x30, 0x0d, 0x06, 0x09,
- 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x02,
- 0x05, 0x00, 0x04, 0x30
-};
-
-static const u8 RSA_digest_info_SHA512[] = {
- 0x30, 0x51, 0x30, 0x0d, 0x06, 0x09,
- 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x03,
- 0x05, 0x00, 0x04, 0x40
-};
-
-static const struct {
- const u8 *data;
- size_t size;
-} RSA_ASN1_templates[PKEY_HASH__LAST] = {
-#define _(X) { RSA_digest_info_##X, sizeof(RSA_digest_info_##X) }
- [HASH_ALGO_MD5] = _(MD5),
- [HASH_ALGO_SHA1] = _(SHA1),
- [HASH_ALGO_RIPE_MD_160] = _(RIPE_MD_160),
- [HASH_ALGO_SHA256] = _(SHA256),
- [HASH_ALGO_SHA384] = _(SHA384),
- [HASH_ALGO_SHA512] = _(SHA512),
- [HASH_ALGO_SHA224] = _(SHA224),
-#undef _
-};
-
-struct rsa_completion {
- struct completion completion;
- int err;
-};
-
-/*
- * Perform the RSA signature verification.
- * @H: Value of hash of data and metadata
- * @EM: The computed signature value
- * @k: The size of EM (EM[0] is an invalid location but should hold 0x00)
- * @hash_size: The size of H
- * @asn1_template: The DigestInfo ASN.1 template
- * @asn1_size: Size of asm1_template[]
- */
-static int rsa_verify(const u8 *H, const u8 *EM, size_t k, size_t hash_size,
- const u8 *asn1_template, size_t asn1_size)
-{
- unsigned PS_end, T_offset, i;
-
- kenter(",,%zu,%zu,%zu", k, hash_size, asn1_size);
-
- if (k < 2 + 1 + asn1_size + hash_size)
- return -EBADMSG;
-
- /* Decode the EMSA-PKCS1-v1_5
- * note: leading zeros are stripped by the RSA implementation
- */
- if (EM[0] != 0x01) {
- kleave(" = -EBADMSG [EM[0] == %02u]", EM[0]);
- return -EBADMSG;
- }
-
- T_offset = k - (asn1_size + hash_size);
- PS_end = T_offset - 1;
- if (EM[PS_end] != 0x00) {
- kleave(" = -EBADMSG [EM[T-1] == %02u]", EM[PS_end]);
- return -EBADMSG;
- }
-
- for (i = 1; i < PS_end; i++) {
- if (EM[i] != 0xff) {
- kleave(" = -EBADMSG [EM[PS%x] == %02u]", i - 2, EM[i]);
- return -EBADMSG;
- }
- }
-
- if (crypto_memneq(asn1_template, EM + T_offset, asn1_size) != 0) {
- kleave(" = -EBADMSG [EM[T] ASN.1 mismatch]");
- return -EBADMSG;
- }
-
- if (crypto_memneq(H, EM + T_offset + asn1_size, hash_size) != 0) {
- kleave(" = -EKEYREJECTED [EM[T] hash mismatch]");
- return -EKEYREJECTED;
- }
-
- kleave(" = 0");
- return 0;
-}
-
-static void public_key_verify_done(struct crypto_async_request *req, int err)
-{
- struct rsa_completion *compl = req->data;
-
- if (err == -EINPROGRESS)
- return;
-
- compl->err = err;
- complete(&compl->completion);
-}
-
-int rsa_verify_signature(const struct public_key *pkey,
- const struct public_key_signature *sig)
-{
- struct crypto_akcipher *tfm;
- struct akcipher_request *req;
- struct rsa_completion compl;
- struct scatterlist sig_sg, sg_out;
- void *outbuf = NULL;
- unsigned int outlen = 0;
- int ret = -ENOMEM;
-
- tfm = crypto_alloc_akcipher("rsa", 0, 0);
- if (IS_ERR(tfm))
- goto error_out;
-
- req = akcipher_request_alloc(tfm, GFP_KERNEL);
- if (!req)
- goto error_free_tfm;
-
- ret = crypto_akcipher_set_pub_key(tfm, pkey->key, pkey->keylen);
- if (ret)
- goto error_free_req;
-
- ret = -EINVAL;
- outlen = crypto_akcipher_maxsize(tfm);
- if (!outlen)
- goto error_free_req;
-
- /* Initialize the output buffer */
- ret = -ENOMEM;
- outbuf = kmalloc(outlen, GFP_KERNEL);
- if (!outbuf)
- goto error_free_req;
-
- sg_init_one(&sig_sg, sig->s, sig->s_size);
- sg_init_one(&sg_out, outbuf, outlen);
- akcipher_request_set_crypt(req, &sig_sg, &sg_out, sig->s_size, outlen);
- init_completion(&compl.completion);
- akcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG |
- CRYPTO_TFM_REQ_MAY_SLEEP,
- public_key_verify_done, &compl);
-
- ret = crypto_akcipher_verify(req);
- if (ret == -EINPROGRESS) {
- wait_for_completion(&compl.completion);
- ret = compl.err;
- }
-
- if (ret)
- goto error_free_req;
-
- /* Output from the operation is an encoded message (EM) of
- * length k octets.
- */
- outlen = req->dst_len;
- ret = rsa_verify(sig->digest, outbuf, outlen, sig->digest_size,
- RSA_ASN1_templates[sig->pkey_hash_algo].data,
- RSA_ASN1_templates[sig->pkey_hash_algo].size);
-error_free_req:
- akcipher_request_free(req);
-error_free_tfm:
- crypto_free_akcipher(tfm);
-error_out:
- kfree(outbuf);
- return ret;
-}
-EXPORT_SYMBOL_GPL(rsa_verify_signature);
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