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-rw-r--r--crypto/asymmetric_keys/x509_public_key.c273
1 files changed, 273 insertions, 0 deletions
diff --git a/crypto/asymmetric_keys/x509_public_key.c b/crypto/asymmetric_keys/x509_public_key.c
new file mode 100644
index 000000000..1815024be
--- /dev/null
+++ b/crypto/asymmetric_keys/x509_public_key.c
@@ -0,0 +1,273 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* Instantiate a public key crypto key from an X.509 Certificate
+ *
+ * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+
+#define pr_fmt(fmt) "X.509: "fmt
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <keys/asymmetric-subtype.h>
+#include <keys/asymmetric-parser.h>
+#include <keys/system_keyring.h>
+#include <crypto/hash.h>
+#include "asymmetric_keys.h"
+#include "x509_parser.h"
+
+/*
+ * Set up the signature parameters in an X.509 certificate. This involves
+ * digesting the signed data and extracting the signature.
+ */
+int x509_get_sig_params(struct x509_certificate *cert)
+{
+ struct public_key_signature *sig = cert->sig;
+ struct crypto_shash *tfm;
+ struct shash_desc *desc;
+ size_t desc_size;
+ int ret;
+
+ pr_devel("==>%s()\n", __func__);
+
+ sig->data = cert->tbs;
+ sig->data_size = cert->tbs_size;
+
+ sig->s = kmemdup(cert->raw_sig, cert->raw_sig_size, GFP_KERNEL);
+ if (!sig->s)
+ return -ENOMEM;
+
+ sig->s_size = cert->raw_sig_size;
+
+ /* Allocate the hashing algorithm we're going to need and find out how
+ * big the hash operational data will be.
+ */
+ tfm = crypto_alloc_shash(sig->hash_algo, 0, 0);
+ if (IS_ERR(tfm)) {
+ if (PTR_ERR(tfm) == -ENOENT) {
+ cert->unsupported_sig = true;
+ return 0;
+ }
+ return PTR_ERR(tfm);
+ }
+
+ desc_size = crypto_shash_descsize(tfm) + sizeof(*desc);
+ sig->digest_size = crypto_shash_digestsize(tfm);
+
+ ret = -ENOMEM;
+ sig->digest = kmalloc(sig->digest_size, GFP_KERNEL);
+ if (!sig->digest)
+ goto error;
+
+ desc = kzalloc(desc_size, GFP_KERNEL);
+ if (!desc)
+ goto error;
+
+ desc->tfm = tfm;
+
+ ret = crypto_shash_digest(desc, cert->tbs, cert->tbs_size, sig->digest);
+ if (ret < 0)
+ goto error_2;
+
+ ret = is_hash_blacklisted(sig->digest, sig->digest_size,
+ BLACKLIST_HASH_X509_TBS);
+ if (ret == -EKEYREJECTED) {
+ pr_err("Cert %*phN is blacklisted\n",
+ sig->digest_size, sig->digest);
+ cert->blacklisted = true;
+ ret = 0;
+ }
+
+error_2:
+ kfree(desc);
+error:
+ crypto_free_shash(tfm);
+ pr_devel("<==%s() = %d\n", __func__, ret);
+ return ret;
+}
+
+/*
+ * Check for self-signedness in an X.509 cert and if found, check the signature
+ * immediately if we can.
+ */
+int x509_check_for_self_signed(struct x509_certificate *cert)
+{
+ int ret = 0;
+
+ pr_devel("==>%s()\n", __func__);
+
+ if (cert->raw_subject_size != cert->raw_issuer_size ||
+ memcmp(cert->raw_subject, cert->raw_issuer,
+ cert->raw_issuer_size) != 0)
+ goto not_self_signed;
+
+ if (cert->sig->auth_ids[0] || cert->sig->auth_ids[1]) {
+ /* If the AKID is present it may have one or two parts. If
+ * both are supplied, both must match.
+ */
+ bool a = asymmetric_key_id_same(cert->skid, cert->sig->auth_ids[1]);
+ bool b = asymmetric_key_id_same(cert->id, cert->sig->auth_ids[0]);
+
+ if (!a && !b)
+ goto not_self_signed;
+
+ ret = -EKEYREJECTED;
+ if (((a && !b) || (b && !a)) &&
+ cert->sig->auth_ids[0] && cert->sig->auth_ids[1])
+ goto out;
+ }
+
+ if (cert->unsupported_sig) {
+ ret = 0;
+ goto out;
+ }
+
+ ret = public_key_verify_signature(cert->pub, cert->sig);
+ if (ret < 0) {
+ if (ret == -ENOPKG) {
+ cert->unsupported_sig = true;
+ ret = 0;
+ }
+ goto out;
+ }
+
+ pr_devel("Cert Self-signature verified");
+ cert->self_signed = true;
+
+out:
+ pr_devel("<==%s() = %d\n", __func__, ret);
+ return ret;
+
+not_self_signed:
+ pr_devel("<==%s() = 0 [not]\n", __func__);
+ return 0;
+}
+
+/*
+ * Attempt to parse a data blob for a key as an X509 certificate.
+ */
+static int x509_key_preparse(struct key_preparsed_payload *prep)
+{
+ struct asymmetric_key_ids *kids;
+ struct x509_certificate *cert;
+ const char *q;
+ size_t srlen, sulen;
+ char *desc = NULL, *p;
+ int ret;
+
+ cert = x509_cert_parse(prep->data, prep->datalen);
+ if (IS_ERR(cert))
+ return PTR_ERR(cert);
+
+ pr_devel("Cert Issuer: %s\n", cert->issuer);
+ pr_devel("Cert Subject: %s\n", cert->subject);
+ pr_devel("Cert Key Algo: %s\n", cert->pub->pkey_algo);
+ pr_devel("Cert Valid period: %lld-%lld\n", cert->valid_from, cert->valid_to);
+
+ cert->pub->id_type = "X509";
+
+ if (cert->unsupported_sig) {
+ public_key_signature_free(cert->sig);
+ cert->sig = NULL;
+ } else {
+ pr_devel("Cert Signature: %s + %s\n",
+ cert->sig->pkey_algo, cert->sig->hash_algo);
+ }
+
+ /* Don't permit addition of blacklisted keys */
+ ret = -EKEYREJECTED;
+ if (cert->blacklisted)
+ goto error_free_cert;
+
+ /* Propose a description */
+ sulen = strlen(cert->subject);
+ if (cert->raw_skid) {
+ srlen = cert->raw_skid_size;
+ q = cert->raw_skid;
+ } else {
+ srlen = cert->raw_serial_size;
+ q = cert->raw_serial;
+ }
+
+ ret = -ENOMEM;
+ desc = kmalloc(sulen + 2 + srlen * 2 + 1, GFP_KERNEL);
+ if (!desc)
+ goto error_free_cert;
+ p = memcpy(desc, cert->subject, sulen);
+ p += sulen;
+ *p++ = ':';
+ *p++ = ' ';
+ p = bin2hex(p, q, srlen);
+ *p = 0;
+
+ kids = kmalloc(sizeof(struct asymmetric_key_ids), GFP_KERNEL);
+ if (!kids)
+ goto error_free_desc;
+ kids->id[0] = cert->id;
+ kids->id[1] = cert->skid;
+ kids->id[2] = asymmetric_key_generate_id(cert->raw_subject,
+ cert->raw_subject_size,
+ "", 0);
+ if (IS_ERR(kids->id[2])) {
+ ret = PTR_ERR(kids->id[2]);
+ goto error_free_kids;
+ }
+
+ /* We're pinning the module by being linked against it */
+ __module_get(public_key_subtype.owner);
+ prep->payload.data[asym_subtype] = &public_key_subtype;
+ prep->payload.data[asym_key_ids] = kids;
+ prep->payload.data[asym_crypto] = cert->pub;
+ prep->payload.data[asym_auth] = cert->sig;
+ prep->description = desc;
+ prep->quotalen = 100;
+
+ /* We've finished with the certificate */
+ cert->pub = NULL;
+ cert->id = NULL;
+ cert->skid = NULL;
+ cert->sig = NULL;
+ desc = NULL;
+ kids = NULL;
+ ret = 0;
+
+error_free_kids:
+ kfree(kids);
+error_free_desc:
+ kfree(desc);
+error_free_cert:
+ x509_free_certificate(cert);
+ return ret;
+}
+
+static struct asymmetric_key_parser x509_key_parser = {
+ .owner = THIS_MODULE,
+ .name = "x509",
+ .parse = x509_key_preparse,
+};
+
+/*
+ * Module stuff
+ */
+extern int __init certs_selftest(void);
+static int __init x509_key_init(void)
+{
+ int ret;
+
+ ret = register_asymmetric_key_parser(&x509_key_parser);
+ if (ret < 0)
+ return ret;
+ return fips_signature_selftest();
+}
+
+static void __exit x509_key_exit(void)
+{
+ unregister_asymmetric_key_parser(&x509_key_parser);
+}
+
+module_init(x509_key_init);
+module_exit(x509_key_exit);
+
+MODULE_DESCRIPTION("X.509 certificate parser");
+MODULE_AUTHOR("Red Hat, Inc.");
+MODULE_LICENSE("GPL");