forked from Minki/linux
b4bfec7f4a
In general the handling of IMA/EVM xattrs is good, but I found a few locations where either the xattr size or the value of the type field in the xattr are not checked. Add a few simple checks to these locations to prevent malformed or malicious xattrs from causing problems. Signed-off-by: Seth Forshee <seth.forshee@canonical.com> Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
138 lines
3.2 KiB
C
138 lines
3.2 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 || siglen < 2)
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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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