v4.19.13 snapshot.
diff --git a/crypto/asymmetric_keys/restrict.c b/crypto/asymmetric_keys/restrict.c
new file mode 100644
index 0000000..7c93c77
--- /dev/null
+++ b/crypto/asymmetric_keys/restrict.c
@@ -0,0 +1,268 @@
+/* Instantiate a public key crypto key from an X.509 Certificate
+ *
+ * Copyright (C) 2012, 2016 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) "ASYM: "fmt
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/err.h>
+#include <crypto/public_key.h>
+#include "asymmetric_keys.h"
+
+static bool use_builtin_keys;
+static struct asymmetric_key_id *ca_keyid;
+
+#ifndef MODULE
+static struct {
+ struct asymmetric_key_id id;
+ unsigned char data[10];
+} cakey;
+
+static int __init ca_keys_setup(char *str)
+{
+ if (!str) /* default system keyring */
+ return 1;
+
+ if (strncmp(str, "id:", 3) == 0) {
+ struct asymmetric_key_id *p = &cakey.id;
+ size_t hexlen = (strlen(str) - 3) / 2;
+ int ret;
+
+ if (hexlen == 0 || hexlen > sizeof(cakey.data)) {
+ pr_err("Missing or invalid ca_keys id\n");
+ return 1;
+ }
+
+ ret = __asymmetric_key_hex_to_key_id(str + 3, p, hexlen);
+ if (ret < 0)
+ pr_err("Unparsable ca_keys id hex string\n");
+ else
+ ca_keyid = p; /* owner key 'id:xxxxxx' */
+ } else if (strcmp(str, "builtin") == 0) {
+ use_builtin_keys = true;
+ }
+
+ return 1;
+}
+__setup("ca_keys=", ca_keys_setup);
+#endif
+
+/**
+ * restrict_link_by_signature - Restrict additions to a ring of public keys
+ * @dest_keyring: Keyring being linked to.
+ * @type: The type of key being added.
+ * @payload: The payload of the new key.
+ * @trust_keyring: A ring of keys that can be used to vouch for the new cert.
+ *
+ * Check the new certificate against the ones in the trust keyring. If one of
+ * those is the signing key and validates the new certificate, then mark the
+ * new certificate as being trusted.
+ *
+ * Returns 0 if the new certificate was accepted, -ENOKEY if we couldn't find a
+ * matching parent certificate in the trusted list, -EKEYREJECTED if the
+ * signature check fails or the key is blacklisted, -ENOPKG if the signature
+ * uses unsupported crypto, or some other error if there is a matching
+ * certificate but the signature check cannot be performed.
+ */
+int restrict_link_by_signature(struct key *dest_keyring,
+ const struct key_type *type,
+ const union key_payload *payload,
+ struct key *trust_keyring)
+{
+ const struct public_key_signature *sig;
+ struct key *key;
+ int ret;
+
+ pr_devel("==>%s()\n", __func__);
+
+ if (!trust_keyring)
+ return -ENOKEY;
+
+ if (type != &key_type_asymmetric)
+ return -EOPNOTSUPP;
+
+ sig = payload->data[asym_auth];
+ if (!sig)
+ return -ENOPKG;
+ if (!sig->auth_ids[0] && !sig->auth_ids[1])
+ return -ENOKEY;
+
+ if (ca_keyid && !asymmetric_key_id_partial(sig->auth_ids[1], ca_keyid))
+ return -EPERM;
+
+ /* See if we have a key that signed this one. */
+ key = find_asymmetric_key(trust_keyring,
+ sig->auth_ids[0], sig->auth_ids[1],
+ false);
+ if (IS_ERR(key))
+ return -ENOKEY;
+
+ if (use_builtin_keys && !test_bit(KEY_FLAG_BUILTIN, &key->flags))
+ ret = -ENOKEY;
+ else
+ ret = verify_signature(key, sig);
+ key_put(key);
+ return ret;
+}
+
+static bool match_either_id(const struct asymmetric_key_ids *pair,
+ const struct asymmetric_key_id *single)
+{
+ return (asymmetric_key_id_same(pair->id[0], single) ||
+ asymmetric_key_id_same(pair->id[1], single));
+}
+
+static int key_or_keyring_common(struct key *dest_keyring,
+ const struct key_type *type,
+ const union key_payload *payload,
+ struct key *trusted, bool check_dest)
+{
+ const struct public_key_signature *sig;
+ struct key *key = NULL;
+ int ret;
+
+ pr_devel("==>%s()\n", __func__);
+
+ if (!dest_keyring)
+ return -ENOKEY;
+ else if (dest_keyring->type != &key_type_keyring)
+ return -EOPNOTSUPP;
+
+ if (!trusted && !check_dest)
+ return -ENOKEY;
+
+ if (type != &key_type_asymmetric)
+ return -EOPNOTSUPP;
+
+ sig = payload->data[asym_auth];
+ if (!sig)
+ return -ENOPKG;
+ if (!sig->auth_ids[0] && !sig->auth_ids[1])
+ return -ENOKEY;
+
+ if (trusted) {
+ if (trusted->type == &key_type_keyring) {
+ /* See if we have a key that signed this one. */
+ key = find_asymmetric_key(trusted, sig->auth_ids[0],
+ sig->auth_ids[1], false);
+ if (IS_ERR(key))
+ key = NULL;
+ } else if (trusted->type == &key_type_asymmetric) {
+ const struct asymmetric_key_ids *signer_ids;
+
+ signer_ids = asymmetric_key_ids(trusted);
+
+ /*
+ * The auth_ids come from the candidate key (the
+ * one that is being considered for addition to
+ * dest_keyring) and identify the key that was
+ * used to sign.
+ *
+ * The signer_ids are identifiers for the
+ * signing key specified for dest_keyring.
+ *
+ * The first auth_id is the preferred id, and
+ * the second is the fallback. If only one
+ * auth_id is present, it may match against
+ * either signer_id. If two auth_ids are
+ * present, the first auth_id must match one
+ * signer_id and the second auth_id must match
+ * the second signer_id.
+ */
+ if (!sig->auth_ids[0] || !sig->auth_ids[1]) {
+ const struct asymmetric_key_id *auth_id;
+
+ auth_id = sig->auth_ids[0] ?: sig->auth_ids[1];
+ if (match_either_id(signer_ids, auth_id))
+ key = __key_get(trusted);
+
+ } else if (asymmetric_key_id_same(signer_ids->id[1],
+ sig->auth_ids[1]) &&
+ match_either_id(signer_ids,
+ sig->auth_ids[0])) {
+ key = __key_get(trusted);
+ }
+ } else {
+ return -EOPNOTSUPP;
+ }
+ }
+
+ if (check_dest && !key) {
+ /* See if the destination has a key that signed this one. */
+ key = find_asymmetric_key(dest_keyring, sig->auth_ids[0],
+ sig->auth_ids[1], false);
+ if (IS_ERR(key))
+ key = NULL;
+ }
+
+ if (!key)
+ return -ENOKEY;
+
+ ret = key_validate(key);
+ if (ret == 0)
+ ret = verify_signature(key, sig);
+
+ key_put(key);
+ return ret;
+}
+
+/**
+ * restrict_link_by_key_or_keyring - Restrict additions to a ring of public
+ * keys using the restrict_key information stored in the ring.
+ * @dest_keyring: Keyring being linked to.
+ * @type: The type of key being added.
+ * @payload: The payload of the new key.
+ * @trusted: A key or ring of keys that can be used to vouch for the new cert.
+ *
+ * Check the new certificate only against the key or keys passed in the data
+ * parameter. If one of those is the signing key and validates the new
+ * certificate, then mark the new certificate as being ok to link.
+ *
+ * Returns 0 if the new certificate was accepted, -ENOKEY if we
+ * couldn't find a matching parent certificate in the trusted list,
+ * -EKEYREJECTED if the signature check fails, -ENOPKG if the signature uses
+ * unsupported crypto, or some other error if there is a matching certificate
+ * but the signature check cannot be performed.
+ */
+int restrict_link_by_key_or_keyring(struct key *dest_keyring,
+ const struct key_type *type,
+ const union key_payload *payload,
+ struct key *trusted)
+{
+ return key_or_keyring_common(dest_keyring, type, payload, trusted,
+ false);
+}
+
+/**
+ * restrict_link_by_key_or_keyring_chain - Restrict additions to a ring of
+ * public keys using the restrict_key information stored in the ring.
+ * @dest_keyring: Keyring being linked to.
+ * @type: The type of key being added.
+ * @payload: The payload of the new key.
+ * @trusted: A key or ring of keys that can be used to vouch for the new cert.
+ *
+ * Check the new certificate only against the key or keys passed in the data
+ * parameter. If one of those is the signing key and validates the new
+ * certificate, then mark the new certificate as being ok to link.
+ *
+ * Returns 0 if the new certificate was accepted, -ENOKEY if we
+ * couldn't find a matching parent certificate in the trusted list,
+ * -EKEYREJECTED if the signature check fails, -ENOPKG if the signature uses
+ * unsupported crypto, or some other error if there is a matching certificate
+ * but the signature check cannot be performed.
+ */
+int restrict_link_by_key_or_keyring_chain(struct key *dest_keyring,
+ const struct key_type *type,
+ const union key_payload *payload,
+ struct key *trusted)
+{
+ return key_or_keyring_common(dest_keyring, type, payload, trusted,
+ true);
+}