111 lines
2.9 KiB
C
111 lines
2.9 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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* Reiner Sailer <sailer@watson.ibm.com>
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* Leendert van Doorn <leendert@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_init.c
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* initialization and cleanup functions
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*/
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#include <linux/module.h>
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#include <linux/scatterlist.h>
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#include <linux/slab.h>
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#include <linux/err.h>
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#include <crypto/hash_info.h>
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#include "ima.h"
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/* name for boot aggregate entry */
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static const char *boot_aggregate_name = "boot_aggregate";
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int ima_used_chip;
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/* Add the boot aggregate to the IMA measurement list and extend
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* the PCR register.
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*
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* Calculate the boot aggregate, a SHA1 over tpm registers 0-7,
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* assuming a TPM chip exists, and zeroes if the TPM chip does not
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* exist. Add the boot aggregate measurement to the measurement
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* list and extend the PCR register.
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*
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* If a tpm chip does not exist, indicate the core root of trust is
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* not hardware based by invalidating the aggregate PCR value.
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* (The aggregate PCR value is invalidated by adding one value to
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* the measurement list and extending the aggregate PCR value with
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* a different value.) Violations add a zero entry to the measurement
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* list and extend the aggregate PCR value with ff...ff's.
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*/
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static void __init ima_add_boot_aggregate(void)
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{
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struct ima_template_entry *entry;
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struct integrity_iint_cache tmp_iint, *iint = &tmp_iint;
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const char *op = "add_boot_aggregate";
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const char *audit_cause = "ENOMEM";
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int result = -ENOMEM;
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int violation = 0;
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struct {
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struct ima_digest_data hdr;
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char digest[TPM_DIGEST_SIZE];
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} hash;
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memset(iint, 0, sizeof(*iint));
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memset(&hash, 0, sizeof(hash));
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iint->ima_hash = &hash.hdr;
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iint->ima_hash->algo = HASH_ALGO_SHA1;
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iint->ima_hash->length = SHA1_DIGEST_SIZE;
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if (ima_used_chip) {
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result = ima_calc_boot_aggregate(&hash.hdr);
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if (result < 0) {
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audit_cause = "hashing_error";
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kfree(entry);
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goto err_out;
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}
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}
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result = ima_alloc_init_template(iint, NULL, boot_aggregate_name,
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NULL, 0, &entry);
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if (result < 0)
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return;
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result = ima_store_template(entry, violation, NULL,
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boot_aggregate_name);
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if (result < 0)
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kfree(entry);
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return;
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err_out:
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integrity_audit_msg(AUDIT_INTEGRITY_PCR, NULL, boot_aggregate_name, op,
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audit_cause, result, 0);
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}
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int __init ima_init(void)
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{
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u8 pcr_i[TPM_DIGEST_SIZE];
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int rc;
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ima_used_chip = 0;
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rc = tpm_pcr_read(TPM_ANY_NUM, 0, pcr_i);
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if (rc == 0)
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ima_used_chip = 1;
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if (!ima_used_chip)
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pr_info("IMA: No TPM chip found, activating TPM-bypass!\n");
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rc = ima_init_crypto();
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if (rc)
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return rc;
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rc = ima_init_template();
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if (rc != 0)
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return rc;
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ima_add_boot_aggregate(); /* boot aggregate must be first entry */
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ima_init_policy();
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return ima_fs_init();
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}
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