56104cf2b8
Add a config option (IMA_KEYRINGS_PERMIT_SIGNED_BY_BUILTIN_OR_SECONDARY) that, when enabled, allows keys to be added to the IMA keyrings by userspace - with the restriction that each must be signed by a key in the system trusted keyrings. EPERM will be returned if this option is disabled, ENOKEY will be returned if no authoritative key can be found and EKEYREJECTED will be returned if the signature doesn't match. Other errors such as ENOPKG may also be returned. If this new option is enabled, the builtin system keyring is searched, as is the secondary system keyring if that is also enabled. Intermediate keys between the builtin system keyring and the key being added can be added to the secondary keyring (which replaces .ima_mok) to form a trust chain - provided they are also validly signed by a key in one of the trusted keyrings. The .ima_mok keyring is then removed and the IMA blacklist keyring gets its own config option (IMA_BLACKLIST_KEYRING). Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
137 lines
3.1 KiB
C
137 lines
3.1 KiB
C
/*
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* Copyright (C) 2011 Intel Corporation
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*
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* Author:
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* Dmitry Kasatkin <dmitry.kasatkin@intel.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, version 2 of the License.
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*
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/err.h>
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#include <linux/sched.h>
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#include <linux/slab.h>
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#include <linux/cred.h>
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#include <linux/key-type.h>
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#include <linux/digsig.h>
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#include <crypto/public_key.h>
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#include <keys/system_keyring.h>
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#include "integrity.h"
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static struct key *keyring[INTEGRITY_KEYRING_MAX];
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static const char *keyring_name[INTEGRITY_KEYRING_MAX] = {
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#ifndef CONFIG_INTEGRITY_TRUSTED_KEYRING
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"_evm",
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"_ima",
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#else
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".evm",
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".ima",
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#endif
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"_module",
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};
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#ifdef CONFIG_INTEGRITY_TRUSTED_KEYRING
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static bool init_keyring __initdata = true;
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#else
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static bool init_keyring __initdata;
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#endif
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#ifdef CONFIG_IMA_KEYRINGS_PERMIT_SIGNED_BY_BUILTIN_OR_SECONDARY
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#define restrict_link_to_ima restrict_link_by_builtin_and_secondary_trusted
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#else
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#define restrict_link_to_ima restrict_link_by_builtin_trusted
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#endif
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int integrity_digsig_verify(const unsigned int id, const char *sig, int siglen,
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const char *digest, int digestlen)
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{
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if (id >= INTEGRITY_KEYRING_MAX)
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return -EINVAL;
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if (!keyring[id]) {
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keyring[id] =
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request_key(&key_type_keyring, keyring_name[id], NULL);
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if (IS_ERR(keyring[id])) {
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int err = PTR_ERR(keyring[id]);
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pr_err("no %s keyring: %d\n", keyring_name[id], err);
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keyring[id] = NULL;
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return err;
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}
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}
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switch (sig[1]) {
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case 1:
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/* v1 API expect signature without xattr type */
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return digsig_verify(keyring[id], sig + 1, siglen - 1,
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digest, digestlen);
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case 2:
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return asymmetric_verify(keyring[id], sig, siglen,
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digest, digestlen);
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}
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return -EOPNOTSUPP;
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}
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int __init integrity_init_keyring(const unsigned int id)
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{
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const struct cred *cred = current_cred();
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int err = 0;
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if (!init_keyring)
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return 0;
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keyring[id] = keyring_alloc(keyring_name[id], KUIDT_INIT(0),
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KGIDT_INIT(0), cred,
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((KEY_POS_ALL & ~KEY_POS_SETATTR) |
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KEY_USR_VIEW | KEY_USR_READ |
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KEY_USR_WRITE | KEY_USR_SEARCH),
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KEY_ALLOC_NOT_IN_QUOTA,
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restrict_link_to_ima, NULL);
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if (IS_ERR(keyring[id])) {
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err = PTR_ERR(keyring[id]);
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pr_info("Can't allocate %s keyring (%d)\n",
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keyring_name[id], err);
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keyring[id] = NULL;
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}
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return err;
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}
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int __init integrity_load_x509(const unsigned int id, const char *path)
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{
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key_ref_t key;
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char *data;
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int rc;
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if (!keyring[id])
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return -EINVAL;
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rc = integrity_read_file(path, &data);
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if (rc < 0)
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return rc;
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key = key_create_or_update(make_key_ref(keyring[id], 1),
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"asymmetric",
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NULL,
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data,
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rc,
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((KEY_POS_ALL & ~KEY_POS_SETATTR) |
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KEY_USR_VIEW | KEY_USR_READ),
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KEY_ALLOC_NOT_IN_QUOTA);
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if (IS_ERR(key)) {
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rc = PTR_ERR(key);
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pr_err("Problem loading X.509 certificate (%d): %s\n",
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rc, path);
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} else {
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pr_notice("Loaded X.509 cert '%s': %s\n",
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key_ref_to_ptr(key)->description, path);
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key_ref_put(key);
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}
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kfree(data);
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return 0;
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}
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