linux/security/integrity/ima/ima_queue.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2005,2006,2007,2008 IBM Corporation
 *
 * Authors:
 * Serge Hallyn <[email protected]>
 * Reiner Sailer <[email protected]>
 * Mimi Zohar <[email protected]>
 *
 * File: ima_queue.c
 *       Implements queues that store template measurements and
 *       maintains aggregate over the stored measurements
 *       in the pre-configured TPM PCR (if available).
 *       The measurement list is append-only. No entry is
 *       ever removed or changed during the boot-cycle.
 */

#include <linux/rculist.h>
#include <linux/slab.h>
#include "ima.h"

#define AUDIT_CAUSE_LEN_MAX …

/* pre-allocated array of tpm_digest structures to extend a PCR */
static struct tpm_digest *digests;

LIST_HEAD(…);	/* list of all measurements */
#ifdef CONFIG_IMA_KEXEC
static unsigned long binary_runtime_size;
#else
static unsigned long binary_runtime_size = ULONG_MAX;
#endif

/* key: inode (before secure-hashing a file) */
struct ima_h_table ima_htable = …;

/* mutex protects atomicity of extending measurement list
 * and extending the TPM PCR aggregate. Since tpm_extend can take
 * long (and the tpm driver uses a mutex), we can't use the spinlock.
 */
static DEFINE_MUTEX(ima_extend_list_mutex);

/* lookup up the digest value in the hash table, and return the entry */
static struct ima_queue_entry *ima_lookup_digest_entry(u8 *digest_value,
						       int pcr)
{ … }

/*
 * Calculate the memory required for serializing a single
 * binary_runtime_measurement list entry, which contains a
 * couple of variable length fields (e.g template name and data).
 */
static int get_binary_runtime_size(struct ima_template_entry *entry)
{ … }

/* ima_add_template_entry helper function:
 * - Add template entry to the measurement list and hash table, for
 *   all entries except those carried across kexec.
 *
 * (Called with ima_extend_list_mutex held.)
 */
static int ima_add_digest_entry(struct ima_template_entry *entry,
				bool update_htable)
{ … }

/*
 * Return the amount of memory required for serializing the
 * entire binary_runtime_measurement list, including the ima_kexec_hdr
 * structure.
 */
unsigned long ima_get_binary_runtime_size(void)
{ … }

static int ima_pcr_extend(struct tpm_digest *digests_arg, int pcr)
{ … }

/*
 * Add template entry to the measurement list and hash table, and
 * extend the pcr.
 *
 * On systems which support carrying the IMA measurement list across
 * kexec, maintain the total memory size required for serializing the
 * binary_runtime_measurements.
 */
int ima_add_template_entry(struct ima_template_entry *entry, int violation,
			   const char *op, struct inode *inode,
			   const unsigned char *filename)
{ … }

int ima_restore_measurement_entry(struct ima_template_entry *entry)
{ … }

int __init ima_init_digests(void)
{ … }