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![Mimi Zohar](/assets/img/avatar_default.png)
In preparation for serializing the binary_runtime_measurements, this patch maintains the amount of memory required. Link: http://lkml.kernel.org/r/1480554346-29071-5-git-send-email-zohar@linux.vnet.ibm.com Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com> Acked-by: Dmitry Kasatkin <dmitry.kasatkin@gmail.com> Cc: Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Andreas Steffen <andreas.steffen@strongswan.org> Cc: Josh Sklar <sklar@linux.vnet.ibm.com> Cc: Dave Young <dyoung@redhat.com> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Baoquan He <bhe@redhat.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Stewart Smith <stewart@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
214 lines
5.7 KiB
C
214 lines
5.7 KiB
C
/*
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* Copyright (C) 2005,2006,2007,2008 IBM Corporation
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*
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* Authors:
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* Serge Hallyn <serue@us.ibm.com>
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* Reiner Sailer <sailer@watson.ibm.com>
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* Mimi Zohar <zohar@us.ibm.com>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation, version 2 of the
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* License.
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*
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* File: ima_queue.c
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* Implements queues that store template measurements and
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* maintains aggregate over the stored measurements
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* in the pre-configured TPM PCR (if available).
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* The measurement list is append-only. No entry is
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* ever removed or changed during the boot-cycle.
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/module.h>
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#include <linux/rculist.h>
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#include <linux/slab.h>
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#include "ima.h"
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#define AUDIT_CAUSE_LEN_MAX 32
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LIST_HEAD(ima_measurements); /* list of all measurements */
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#ifdef CONFIG_IMA_KEXEC
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static unsigned long binary_runtime_size;
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#else
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static unsigned long binary_runtime_size = ULONG_MAX;
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#endif
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/* key: inode (before secure-hashing a file) */
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struct ima_h_table ima_htable = {
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.len = ATOMIC_LONG_INIT(0),
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.violations = ATOMIC_LONG_INIT(0),
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.queue[0 ... IMA_MEASURE_HTABLE_SIZE - 1] = HLIST_HEAD_INIT
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};
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/* mutex protects atomicity of extending measurement list
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* and extending the TPM PCR aggregate. Since tpm_extend can take
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* long (and the tpm driver uses a mutex), we can't use the spinlock.
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*/
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static DEFINE_MUTEX(ima_extend_list_mutex);
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/* lookup up the digest value in the hash table, and return the entry */
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static struct ima_queue_entry *ima_lookup_digest_entry(u8 *digest_value,
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int pcr)
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{
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struct ima_queue_entry *qe, *ret = NULL;
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unsigned int key;
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int rc;
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key = ima_hash_key(digest_value);
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rcu_read_lock();
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hlist_for_each_entry_rcu(qe, &ima_htable.queue[key], hnext) {
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rc = memcmp(qe->entry->digest, digest_value, TPM_DIGEST_SIZE);
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if ((rc == 0) && (qe->entry->pcr == pcr)) {
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ret = qe;
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break;
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}
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}
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rcu_read_unlock();
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return ret;
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}
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/*
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* Calculate the memory required for serializing a single
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* binary_runtime_measurement list entry, which contains a
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* couple of variable length fields (e.g template name and data).
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*/
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static int get_binary_runtime_size(struct ima_template_entry *entry)
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{
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int size = 0;
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size += sizeof(u32); /* pcr */
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size += sizeof(entry->digest);
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size += sizeof(int); /* template name size field */
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size += strlen(entry->template_desc->name) + 1;
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size += sizeof(entry->template_data_len);
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size += entry->template_data_len;
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return size;
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}
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/* ima_add_template_entry helper function:
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* - Add template entry to the measurement list and hash table, for
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* all entries except those carried across kexec.
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*
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* (Called with ima_extend_list_mutex held.)
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*/
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static int ima_add_digest_entry(struct ima_template_entry *entry,
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bool update_htable)
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{
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struct ima_queue_entry *qe;
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unsigned int key;
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qe = kmalloc(sizeof(*qe), GFP_KERNEL);
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if (qe == NULL) {
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pr_err("OUT OF MEMORY ERROR creating queue entry\n");
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return -ENOMEM;
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}
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qe->entry = entry;
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INIT_LIST_HEAD(&qe->later);
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list_add_tail_rcu(&qe->later, &ima_measurements);
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atomic_long_inc(&ima_htable.len);
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if (update_htable) {
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key = ima_hash_key(entry->digest);
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hlist_add_head_rcu(&qe->hnext, &ima_htable.queue[key]);
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}
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if (binary_runtime_size != ULONG_MAX) {
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int size;
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size = get_binary_runtime_size(entry);
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binary_runtime_size = (binary_runtime_size < ULONG_MAX - size) ?
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binary_runtime_size + size : ULONG_MAX;
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}
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return 0;
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}
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/*
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* Return the amount of memory required for serializing the
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* entire binary_runtime_measurement list, including the ima_kexec_hdr
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* structure.
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*/
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unsigned long ima_get_binary_runtime_size(void)
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{
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if (binary_runtime_size >= (ULONG_MAX - sizeof(struct ima_kexec_hdr)))
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return ULONG_MAX;
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else
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return binary_runtime_size + sizeof(struct ima_kexec_hdr);
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};
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static int ima_pcr_extend(const u8 *hash, int pcr)
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{
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int result = 0;
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if (!ima_used_chip)
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return result;
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result = tpm_pcr_extend(TPM_ANY_NUM, pcr, hash);
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if (result != 0)
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pr_err("Error Communicating to TPM chip, result: %d\n", result);
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return result;
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}
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/*
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* Add template entry to the measurement list and hash table, and
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* extend the pcr.
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*
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* On systems which support carrying the IMA measurement list across
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* kexec, maintain the total memory size required for serializing the
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* binary_runtime_measurements.
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*/
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int ima_add_template_entry(struct ima_template_entry *entry, int violation,
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const char *op, struct inode *inode,
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const unsigned char *filename)
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{
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u8 digest[TPM_DIGEST_SIZE];
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const char *audit_cause = "hash_added";
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char tpm_audit_cause[AUDIT_CAUSE_LEN_MAX];
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int audit_info = 1;
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int result = 0, tpmresult = 0;
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mutex_lock(&ima_extend_list_mutex);
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if (!violation) {
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memcpy(digest, entry->digest, sizeof(digest));
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if (ima_lookup_digest_entry(digest, entry->pcr)) {
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audit_cause = "hash_exists";
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result = -EEXIST;
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goto out;
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}
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}
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result = ima_add_digest_entry(entry, 1);
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if (result < 0) {
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audit_cause = "ENOMEM";
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audit_info = 0;
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goto out;
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}
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if (violation) /* invalidate pcr */
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memset(digest, 0xff, sizeof(digest));
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tpmresult = ima_pcr_extend(digest, entry->pcr);
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if (tpmresult != 0) {
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snprintf(tpm_audit_cause, AUDIT_CAUSE_LEN_MAX, "TPM_error(%d)",
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tpmresult);
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audit_cause = tpm_audit_cause;
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audit_info = 0;
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}
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out:
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mutex_unlock(&ima_extend_list_mutex);
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integrity_audit_msg(AUDIT_INTEGRITY_PCR, inode, filename,
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op, audit_cause, result, audit_info);
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return result;
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}
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int ima_restore_measurement_entry(struct ima_template_entry *entry)
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{
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int result = 0;
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mutex_lock(&ima_extend_list_mutex);
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result = ima_add_digest_entry(entry, 0);
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mutex_unlock(&ima_extend_list_mutex);
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return result;
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}
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