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Subject[RFC][Patch 4/6] integrity: IMA integrity_measure() support
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Date
This is a re-release of Integrity Measurement Architecture(IMA) as a
method of providing support for the integrity service framework API
integrity_measure() call. When integrity_measure() is called, IMA
submits the measurement (hash) of the file to the TPM chip, for
inclusion in one of the chip's Platform Configuration Registers (PCR).
IMA also keeps a list of all file names and hashes that have been
submitted to the TPM, which can be viewed through securityfs. By
separately requesting a TPM_Quote from the chip, an application can
get a chip-signed value of the PCR, which, along with the list of
measurements from IMA, can be used to attest, or prove to a third
party, the validity of the hash list. (The tpm-3.2.1 package includes
example TPM applications for creating keys, and performing the
TPM_Quote operation.)

IMA can be included or excluded in the kernel configuration. If
included in the kernel, IMA can also be enabled or disabled on the
kernel command line with evm_enable_ima=0.

Index: linux-2.6.21-rc3-mm2/security/evm/Kconfig
===================================================================
--- linux-2.6.21-rc3-mm2.orig/security/evm/Kconfig
+++ linux-2.6.21-rc3-mm2/security/evm/Kconfig
@@ -15,3 +15,4 @@ config INTEGRITY_EVM

If you are unsure how to answer this question, answer N.

+source security/evm/ima/Kconfig
Index: linux-2.6.21-rc3-mm2/security/evm/Makefile
===================================================================
--- linux-2.6.21-rc3-mm2.orig/security/evm/Makefile
+++ linux-2.6.21-rc3-mm2/security/evm/Makefile
@@ -3,3 +3,6 @@ obj-$(CONFIG_INTEGRITY_EVM) += evm.o

evm-y := evm_main.o evm_config.o evm_crypto.o evm_secfs.o

+ifeq ($(CONFIG_IMA_MEASURE), y)
+evm-y += ima/ima_fs.o ima/ima_queue.o ima/ima_init.o ima/ima_main.o
+endif
Index: linux-2.6.21-rc3-mm2/security/evm/evm_integrity.h
===================================================================
--- /dev/null
+++ linux-2.6.21-rc3-mm2/security/evm/evm_integrity.h
@@ -0,0 +1,49 @@
+/*
+ * These functions enable EVM to be compiled with/without IMA.
+ * The configuration parameter "evm_enable_ima" enables/disables
+ * at runtime.
+ */
+
+#include "ima/ima_evm.h"
+
+extern unsigned int evm_enable_ima;
+
+#ifdef CONFIG_IMA_MEASURE
+static inline int evm_ima_init(void)
+{
+ if (evm_enable_ima)
+ return ima_init();
+}
+
+static inline void evm_ima_measure(const unsigned char *name, int hash_len,
+ char *hash)
+{
+ if (evm_enable_ima)
+ ima_measure(name, hash_len, hash);
+}
+
+static inline void evm_ima_cleanup(void)
+{
+ if (evm_enable_ima)
+ ima_cleanup();
+ evm_enable_ima = 0;
+}
+
+#else
+static inline int evm_ima_init(void)
+{
+ evm_enable_ima = 0;
+ return 0;
+}
+
+static inline void evm_ima_measure(const unsigned char *name, int hash_len,
+ char *hash)
+{
+ return;
+}
+
+static inline void evm_ima_cleanup(void)
+{
+ evm_enable_ima = 0;
+}
+#endif
Index: linux-2.6.21-rc3-mm2/security/evm/evm_secfs.c
===================================================================
--- linux-2.6.21-rc3-mm2.orig/security/evm/evm_secfs.c
+++ linux-2.6.21-rc3-mm2/security/evm/evm_secfs.c
@@ -20,7 +20,7 @@
extern int evm_initialized;

static struct dentry *evm_secdir, *evm_config;
-static struct dentry *evm_dir, *evm_cache, *evm_crypto, *evm_xattr;
+static struct dentry *evm_dir, *evm_cache, *evm_crypto, *evm_xattr, *evm_ima;

static int evm_open_debug(struct inode *inode, struct file *file)
{
@@ -62,6 +62,10 @@ static ssize_t evm_read_debug(struct fil
len = sprintf(page, "evm_debug: crypto: %s\n",
((evm_debug & EVM_CRYPTO) == EVM_CRYPTO)
? "ON" : "OFF");
+ else if (strcmp(file->private_data, "ima") == 0)
+ len = sprintf(page, "evm_debug: ima: %s\n",
+ ((evm_debug & EVM_IMA) == EVM_IMA)
+ ? "ON" : "OFF");
else
len = sprintf(page, "unknown evm_debug option\n");

@@ -87,6 +91,9 @@ static ssize_t evm_write_debug(struct fi
else if (strcmp(file->private_data, "crypto") == 0)
evm_debug = (flag == '0') ? evm_debug & ~EVM_CRYPTO :
evm_debug | EVM_CRYPTO;
+ else if (strcmp(file->private_data, "ima") == 0)
+ evm_debug = (flag == '0') ? evm_debug & ~EVM_IMA :
+ evm_debug | EVM_IMA;
return buflen;
}

@@ -169,12 +176,20 @@ int __init evm_init_secfs(void)
if (!evm_crypto || IS_ERR(evm_crypto))
goto out_del_cache;

+ evm_ima = debugfs_create_file("ima", S_IRUSR | S_IRGRP, evm_dir,
+ "ima", &evm_debug_ops);
+ if (!evm_ima || IS_ERR(evm_ima))
+ goto out_del_crypto;
+
evm_xattr = debugfs_create_file("xattr", S_IRUSR | S_IRGRP, evm_dir,
"xattr", &evm_debug_ops);
if (!evm_xattr || IS_ERR(evm_xattr))
- goto out_del_crypto;
+ goto out_del_ima;
+
return 0;

+out_del_ima:
+ debugfs_remove(evm_ima);
out_del_crypto:
debugfs_remove(evm_crypto);
out_del_cache:
@@ -192,6 +207,7 @@ void __exit evm_cleanup_secfs(void)
{
debugfs_remove(evm_xattr);
debugfs_remove(evm_crypto);
+ debugfs_remove(evm_ima);
debugfs_remove(evm_cache);
debugfs_remove(evm_dir);
if (evm_config)
Index: linux-2.6.21-rc3-mm2/security/evm/ima/Kconfig
===================================================================
--- /dev/null
+++ linux-2.6.21-rc3-mm2/security/evm/ima/Kconfig
@@ -0,0 +1,31 @@
+#
+# IBM Integrity Measurement Architecture
+#
+
+#menu "TPM-based Integrity Measurement Architecture"
+
+config IMA_MEASURE
+ bool "TCG run-time Integrity Measurement Architecture"
+ depends on SECURITY && (CRYPTO_SHA1=y) && INTEGRITY_EVM
+ depends on ACPI
+ help
+ IMA maintains a list of hash values of executables and
+ other sensitive system files loaded into the run-time
+ of this system. If your system has a TPM chip, then IMA
+ also maintains an aggregate integrity value over this
+ list inside the TPM hardware. These measurements and
+ the aggregate (signed inside the TPM) can be retrieved
+ and presented to remote parties to establish system
+ properties. If unsure, say N.
+
+config IMA_MEASURE_PCR_IDX
+ int "PCR for Aggregate (8<= Index <= 14)"
+ depends on IMA_MEASURE
+ range 8 14
+ default 10
+ help
+ IMA_MEASURE_PCR_IDX determines the TPM PCR register index
+ that IMA uses to maintain the integrity aggregate of the
+ measurement list. If unsure, use the default 10.
+#endmenu
+
Index: linux-2.6.21-rc3-mm2/security/evm/ima/ima.h
===================================================================
--- /dev/null
+++ linux-2.6.21-rc3-mm2/security/evm/ima/ima.h
@@ -0,0 +1,104 @@
+/*
+ * Copyright (C) 2005,2006,2007 IBM Corporation
+ *
+ * Reiner Sailer <sailer@watson.ibm.com>
+ *
+ * IBM Integrity Measurement Architecture for evm/slim.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation, version 2 of the
+ * License.
+ *
+ * File: ima.h
+ * internal ima definitions
+ */
+
+#ifndef __LINUX_IMA_H
+#define __LINUX_IMA_H
+
+#include <linux/types.h>
+#include <linux/crypto.h>
+#include <linux/security.h>
+#include <linux/hash.h>
+#include <linux/tpm.h>
+
+#define ima_printk(level, format, arg...) \
+ printk(level "ima (%s): " format ,__func__, ## arg)
+
+#define ima_error(format, arg...) \
+ ima_printk(KERN_ERR, format, ## arg)
+
+#define ima_info(format, arg...) \
+ ima_printk(KERN_INFO, format, ## arg)
+
+/* digest size for IMA, fits SHA1 or MD5 */
+#define IMA_DIGEST_SIZE 20
+#define TCG_EVENT_NAME_LEN_MAX 255
+
+#define IMA_HASH_BITS 9
+#define MEASURE_HTABLE_SIZE (1 << IMA_HASH_BITS)
+#define HASH_KEY(digest) (hash_long( \
+ (unsigned long)(*digest), IMA_HASH_BITS));
+
+/* set during initialization */
+extern int ima_used_chip;
+
+struct measure_entry {
+ u32 measure_flags;
+ u8 digest[IMA_DIGEST_SIZE]; /* sha1 or md5 measurement hash */
+ char file_name[TCG_EVENT_NAME_LEN_MAX + 1]; /* name + \0 */
+};
+
+struct queue_entry {
+ struct hlist_node hnext; /* place in hash collision list */
+ struct list_head later; /* place in ima_measurements list */
+ struct measure_entry *entry;
+};
+
+extern struct list_head ima_measurements; /* list of all measurements */
+
+/* declarations */
+int ima_fs_init(void);
+void ima_fs_cleanup(void);
+void create_htable(void);
+void ima_invalidate_pcr(char *);
+int ima_add_measure_entry(struct measure_entry *entry);
+struct queue_entry *ima_lookup_digest_entry(u8 * digest);
+
+/*
+ * used to protect h_table and sha_table
+ */
+extern spinlock_t ima_queue_lock;
+
+struct ima_h_table {
+ atomic_t len; /* number of stored measurements in the list */
+ atomic_t violations;
+ unsigned int max_htable_size;
+ struct hlist_head queue[MEASURE_HTABLE_SIZE];
+ atomic_t queue_len[MEASURE_HTABLE_SIZE];
+};
+extern struct ima_h_table ima_htable;
+
+/* TPM "Glue" definitions */
+
+#define IMA_TPM ((TPM_ANY_TYPE<<16)| TPM_ANY_NUM)
+static inline void ima_extend(const u8 * hash)
+{
+ if (!ima_used_chip)
+ return;
+
+ if (tpm_pcr_extend(IMA_TPM, CONFIG_IMA_MEASURE_PCR_IDX, hash) != 0)
+ ima_error("Error Communicating to TPM chip\n");
+}
+
+static inline void ima_pcrread(int idx, u8 * pcr, int pcr_size)
+{
+ if (!ima_used_chip)
+ return;
+
+ if (tpm_pcr_read(IMA_TPM, idx, pcr, pcr_size) != 0) {
+ ima_error("Error Communicating to TPM chip\n");
+ }
+}
+#endif
Index: linux-2.6.21-rc3-mm2/security/evm/ima/ima_evm.h
===================================================================
--- /dev/null
+++ linux-2.6.21-rc3-mm2/security/evm/ima/ima_evm.h
@@ -0,0 +1,18 @@
+/*
+ * Copyright (C) 2005,2007 IBM Corporation
+ *
+ * Reiner Sailer <sailer@watson.ibm.com>
+ *
+ * IBM Integrity Measurement Architecture for evm/slim.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation, version 2 of the
+ * License.
+ *
+ * File: ima_evm.h
+ * exported ima functions
+ */
+int ima_init(void);
+void ima_cleanup(void);
+void ima_measure(const unsigned char *name, int hash_len, char *hash);
Index: linux-2.6.21-rc3-mm2/security/evm/ima/ima_fs.c
===================================================================
--- /dev/null
+++ linux-2.6.21-rc3-mm2/security/evm/ima/ima_fs.c
@@ -0,0 +1,284 @@
+/*
+ * Copyright (C) 2005,2006,2007 IBM Corporation
+ *
+ * Kylene Hall <kjhall@us.ibm.com>
+ * Reiner Sailer <sailer@us.ibm.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation, version 2 of the
+ * License.
+ *
+ * File: ima_fs.c
+ * implemenents security file system for reporting
+ * current measurement list and IMA statistics
+ */
+#include <linux/module.h>
+#include <linux/seq_file.h>
+
+#include "ima.h"
+
+#define TMPBUFLEN 12
+static ssize_t ima_show_htable_value(char __user * buf, size_t count,
+ loff_t * ppos, atomic_t * val)
+{
+ char tmpbuf[TMPBUFLEN];
+ ssize_t len;
+
+ len = scnprintf(tmpbuf, TMPBUFLEN, "%i\n", atomic_read(val));
+ return simple_read_from_buffer(buf, count, ppos, tmpbuf, len);
+}
+
+static ssize_t ima_show_htable_violations(struct file *filp,
+ char __user * buf,
+ size_t count, loff_t * ppos)
+{
+ return ima_show_htable_value(buf, count, ppos, &ima_htable.violations);
+}
+
+static struct file_operations ima_htable_violations_ops = {
+ .read = ima_show_htable_violations
+};
+
+static ssize_t ima_show_measurements_count(struct file *filp,
+ char __user * buf,
+ size_t count, loff_t * ppos)
+{
+ return ima_show_htable_value(buf, count, ppos, &ima_htable.len);
+
+}
+
+static struct file_operations ima_measurements_count_ops = {
+ .read = ima_show_measurements_count
+};
+
+/* returns pointer to hlist_node */
+static void *ima_measurements_start(struct seq_file *m, loff_t * pos)
+{
+ struct list_head *lpos;
+ loff_t l = *pos;
+ /* we need a lock since pos could point beyond last element */
+ rcu_read_lock();
+ list_for_each_rcu(lpos, &ima_measurements) {
+ if (!l--) {
+ rcu_read_unlock();
+ return lpos;
+ }
+ }
+ rcu_read_unlock();
+ return NULL;
+}
+
+static void *ima_measurements_next(struct seq_file *m, void *v,
+ loff_t * pos)
+{
+ /* lock protects when reading beyond last element
+ * against concurrent list-extension */
+ struct list_head *lpos = (struct list_head *) v;
+
+ rcu_read_lock();
+ lpos = rcu_dereference(lpos->next);
+ rcu_read_unlock();
+ (*pos)++;
+
+ return (lpos == &ima_measurements) ? NULL : lpos;
+}
+
+static void ima_measurements_stop(struct seq_file *m, void *v)
+{
+}
+
+
+/* print format:
+ * 32bit-le=pcr#
+ * 32bit-le=type# << flag
+ * char[20]=digest
+ * 32bit-le=eventDataSize n
+ * eventdata[n] = filename
+ *
+ * flags bits:
+ * 31-16 application flags,
+ * 15-3 kernel flags,
+ * 2-0 hook
+ */
+static int ima_measurements_show(struct seq_file *m, void *v)
+{
+ /* the list never shrinks, so we don't need a lock here */
+ struct list_head *lpos = v;
+ struct queue_entry *qe;
+ struct measure_entry *e;
+ int filename_len;
+ int i;
+ u32 pcr = CONFIG_IMA_MEASURE_PCR_IDX;
+ char data[4];
+
+ /* get entry */
+ qe = list_entry(lpos, struct queue_entry, later);
+ e = qe->entry;
+ if (e == NULL)
+ return -1;
+
+ /*
+ * 1st: PCRIndex
+ * PCR used is always the same (config option) in
+ * little-endian format
+ */
+ memcpy(data, &pcr, 4);
+ for (i = 0; i < 4; i++)
+ seq_putc(m, data[i]);
+
+ /* 2nd: eventtype (=flags) */
+ memcpy(data, &e->measure_flags, 4);
+ for (i = 0; i < 4; i++)
+ seq_putc(m, data[i]);
+
+ /* 3rd: digest */
+ for (i = 0; i < 20; i++)
+ seq_putc(m, e->digest[i]);
+
+ /* 4th: eventDataSize */
+ filename_len = strlen(e->file_name);
+ if (filename_len > TCG_EVENT_NAME_LEN_MAX)
+ filename_len = TCG_EVENT_NAME_LEN_MAX;
+
+ memcpy(data, &filename_len, 4);
+ for (i = 0; i < 4; i++)
+ seq_putc(m, data[i]);
+
+ /* 5th: filename */
+
+ for (i = 0; i < filename_len; i++)
+ seq_putc(m, e->file_name[i]);
+
+ return 0;
+}
+
+static struct seq_operations ima_measurments_seqops = {
+ .start = ima_measurements_start,
+ .next = ima_measurements_next,
+ .stop = ima_measurements_stop,
+ .show = ima_measurements_show
+};
+
+static int ima_measurements_open(struct inode *inode, struct file *file)
+{
+ return seq_open(file, &ima_measurments_seqops);
+}
+
+static struct file_operations ima_measurements_ops = {
+ .open = ima_measurements_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = seq_release,
+};
+
+
+/* print in ascii */
+static int ima_ascii_measurements_show(struct seq_file *m, void *v)
+{
+ /* the list never shrinks, so we don't need a lock here */
+ struct list_head *lpos = v;
+ struct queue_entry *qe;
+ struct measure_entry *e;
+ int i;
+
+ /* get entry */
+ qe = list_entry(lpos, struct queue_entry, later);
+ e = qe->entry;
+ if (e == NULL)
+ return -1;
+
+ /* 1st: PCR used (config option) */
+ seq_printf(m, "%2d ", CONFIG_IMA_MEASURE_PCR_IDX);
+
+ /* 2nd: SHA1 */
+ for (i = 0; i < 20; i++)
+ seq_printf(m, "%02x", e->digest[i]);
+
+ /* 3th: filename <= max + \'0' delimiter */
+ seq_printf(m, " %s\n", e->file_name);
+
+ return 0;
+}
+
+static struct seq_operations ima_ascii_measurements_seqops = {
+ .start = ima_measurements_start,
+ .next = ima_measurements_next,
+ .stop = ima_measurements_stop,
+ .show = ima_ascii_measurements_show
+};
+
+static int ima_ascii_measurements_open(struct inode *inode,
+ struct file *file)
+{
+ return seq_open(file, &ima_ascii_measurements_seqops);
+}
+
+static struct file_operations ima_ascii_measurements_ops = {
+ .open = ima_ascii_measurements_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = seq_release,
+};
+
+static struct dentry
+ *ima_dir = NULL,
+ *binary_runtime_measurements = NULL,
+ *ascii_runtime_measurements = NULL,
+ *runtime_measurements_count = NULL,
+ *violations = NULL;
+
+int ima_fs_init(void)
+{
+
+ ima_dir = securityfs_create_dir("ima", NULL);
+ if (!ima_dir || IS_ERR(ima_dir))
+ return -1;
+
+
+ binary_runtime_measurements =
+ securityfs_create_file("binary_runtime_measurements",
+ S_IRUSR | S_IRGRP, ima_dir, NULL,
+ &ima_measurements_ops);
+ if (!binary_runtime_measurements || IS_ERR(binary_runtime_measurements))
+ goto out;
+
+ ascii_runtime_measurements =
+ securityfs_create_file("ascii_runtime_measurements",
+ S_IRUSR | S_IRGRP, ima_dir, NULL,
+ &ima_ascii_measurements_ops);
+ if (!ascii_runtime_measurements || IS_ERR(ascii_runtime_measurements))
+ goto out;
+
+ runtime_measurements_count =
+ securityfs_create_file("runtime_measurements_count",
+ S_IRUSR | S_IRGRP, ima_dir, NULL,
+ &ima_measurements_count_ops);
+ if (!runtime_measurements_count || IS_ERR(runtime_measurements_count))
+ goto out;
+
+ violations =
+ securityfs_create_file("violations", S_IRUSR | S_IRGRP,
+ ima_dir, NULL,
+ &ima_htable_violations_ops);
+ if (!violations || IS_ERR(violations))
+ goto out;
+ return 0;
+
+
+out:
+ securityfs_remove(runtime_measurements_count);
+ securityfs_remove(ascii_runtime_measurements);
+ securityfs_remove(binary_runtime_measurements);
+ securityfs_remove(ima_dir);
+ return -1;
+}
+
+void __exit ima_fs_cleanup(void)
+{
+ securityfs_remove(violations);
+ securityfs_remove(runtime_measurements_count);
+ securityfs_remove(ascii_runtime_measurements);
+ securityfs_remove(binary_runtime_measurements);
+ securityfs_remove(ima_dir);
+}
Index: linux-2.6.21-rc3-mm2/security/evm/ima/ima_init.c
===================================================================
--- /dev/null
+++ linux-2.6.21-rc3-mm2/security/evm/ima/ima_init.c
@@ -0,0 +1,117 @@
+/*
+ * Copyright (C) 2005,2006,2007 IBM Corporation
+ *
+ * Reiner Sailer <sailer@watson.ibm.com>
+ * Leendert van Doorn <leendert@watson.ibm.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation, version 2 of the
+ * License.
+ *
+ * File: ima_init.c
+ * initialization and cleanup functions
+ */
+#include <linux/module.h>
+#include <asm/scatterlist.h>
+#include <linux/scatterlist.h>
+#include "ima.h"
+#include "ima_evm.h"
+
+/* name for boot aggregate entry */
+static char *boot_aggregate_name = "boot_aggregate";
+static const char version[] = "v7.6 02/27/2007";
+static const char illegal_pcr[20] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
+
+int ima_used_chip = 0;
+
+static void ima_add_boot_aggregate(void)
+{
+ /* cumulative sha1 over tpm registers 0-7 */
+ struct measure_entry *entry;
+ size_t count;
+ int err;
+
+ /* create new entry for boot aggregate */
+ entry = (struct measure_entry *)
+ kzalloc(sizeof(struct measure_entry), GFP_ATOMIC);
+ if (entry == NULL) {
+ ima_invalidate_pcr("error allocating new measurement entry");
+ return;
+ }
+ if ((count = strlen(boot_aggregate_name)) > TCG_EVENT_NAME_LEN_MAX)
+ count = TCG_EVENT_NAME_LEN_MAX;
+ memcpy(entry->file_name, boot_aggregate_name, count);
+ entry->file_name[count] = '\0';
+ if (ima_used_chip) {
+ int i;
+ u8 pcr_i[20];
+ struct hash_desc desc;
+ struct crypto_hash *tfm;
+ struct scatterlist sg;
+
+ tfm = crypto_alloc_hash("sha1", 0, CRYPTO_ALG_ASYNC);
+ if (!tfm || IS_ERR(tfm)) {
+ kfree(entry);
+ ima_error("error initializing digest.\n");
+ return;
+ }
+ desc.tfm = tfm;
+ desc.flags = 0;
+ crypto_hash_init(&desc);
+
+ for (i = 0; i < 8; i++) {
+ ima_pcrread(i, pcr_i, sizeof(pcr_i));
+ /* now accumulate with current aggregate */
+ sg_init_one(&sg, (u8 *)pcr_i, 20);
+ crypto_hash_update(&desc, &sg, 20);
+ }
+ crypto_hash_final(&desc, entry->digest);
+ crypto_free_hash(tfm);
+ } else
+ memset(entry->digest, 0xff, 20);
+
+ /* now add measurement; if TPM bypassed, we have a ff..ff entry */
+ err = ima_add_measure_entry(entry);
+ if (err < 0) {
+ kfree(entry);
+ if (err != -EEXIST)
+ ima_invalidate_pcr("error adding boot aggregate");
+ }
+}
+
+/* general invalidation function called by the measurement code */
+void ima_invalidate_pcr(char *cause)
+{
+ /* extend pcr with illegal digest (no digest yields 0) */
+ /* extending twice is obviously flagging the exception condition. */
+ ima_error("INVALIDATING PCR AGGREGATE. Cause=%s.\n", cause);
+ ima_extend(illegal_pcr);
+ ima_extend(illegal_pcr);
+ atomic_inc(&ima_htable.violations); /* can overflow; indicator only */
+}
+
+int ima_init(void)
+{
+ int rc;
+
+ ima_used_chip = 0;
+ rc = tpm_pcr_read(IMA_TPM, 0, NULL, 0);
+ if (rc == 0)
+ ima_used_chip = 1;
+
+ if (!ima_used_chip)
+ ima_info("No TPM chip found(rc = %d), activating TPM-bypass!\n", rc);
+
+ create_htable(); /* for measurements */
+
+ /* boot aggregate must be very first entry */
+ ima_add_boot_aggregate();
+
+ return ima_fs_init();
+}
+
+void ima_cleanup(void)
+{
+ ima_fs_cleanup();
+}
Index: linux-2.6.21-rc3-mm2/security/evm/ima/ima_main.c
===================================================================
--- /dev/null
+++ linux-2.6.21-rc3-mm2/security/evm/ima/ima_main.c
@@ -0,0 +1,87 @@
+/*
+ * Copyright (C) 2005,2006,2007 IBM Corporation
+ *
+ * Authors:
+ * Reiner Sailer <sailer@watson.ibm.com>
+ * Serge Hallyn <serue@us.ibm.com>
+ * Kylene Hall <kylene@us.ibm.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation, version 2 of the
+ * License.
+ *
+ * File: ima_main.c
+ * implements file measurements and their storage
+ */
+#include <linux/module.h>
+
+#include "ima.h"
+#include "ima_evm.h"
+
+/**
+ * ima_measure - collect and protect measurements
+ * @name:ascii file name associated with the measurement hash
+ * @hash_len:length of hash value in bytes (16 for MD5, 20 for SHA1)
+ * @hash:actual hash value pre-calculated by evm/slim
+ *
+ * Description:ima_measure creates a new measurement entry out of @hash
+ * and @name and adds this entry to an ordered list of
+ * measurements entries maintained inside the kernel. If
+ * @hash_len is less than 20 then the remaining digest bytes
+ * will be zero. It also updates the aggregate integrity value
+ * (maintained inside the configured TPM PCR) over the hashes
+ * of the current list of measurement entries.
+ *
+ * Applications retrieve the current kernel-held measurement
+ * list through the securityfs entries in
+ * /sys/kernel/security/ima. The signed aggregate TPM PCR
+ * (called quote) can be retrieved using a TPM user space
+ * library and is used to validate the measurement list.
+ */
+void ima_measure(const unsigned char *name, int hash_len, char *hash)
+{
+ struct measure_entry *entry;
+ u8 digest[IMA_DIGEST_SIZE];
+ int err = 0, count;
+
+ if (hash_len > IMA_DIGEST_SIZE) {
+ ima_info
+ ("%s: SLIM digest too long. Cutting to %x bytes.\n",
+ __func__, IMA_DIGEST_SIZE);
+ hash_len = IMA_DIGEST_SIZE;
+ }
+
+ memset(digest, 0, IMA_DIGEST_SIZE);
+
+ if (!memcmp(digest, hash, IMA_DIGEST_SIZE))
+ ima_error("Error, NULL hash value!\n");
+
+ memcpy(digest, hash, hash_len);
+
+ /* hash exists already? */
+ if (ima_lookup_digest_entry(digest))
+ return;
+
+ /* create new entry and add to measurement list */
+ entry = kzalloc(sizeof(struct measure_entry), GFP_ATOMIC);
+ if (!entry) {
+ ima_error("Error allocating new measurement entry");
+ return; /* invalidate pcr */
+ }
+
+ entry->measure_flags = 0;
+ if ((count = strlen(name)) > TCG_EVENT_NAME_LEN_MAX)
+ count = TCG_EVENT_NAME_LEN_MAX;
+
+ memcpy(entry->file_name, name, count);
+ entry->file_name[count] = '\0';
+ memcpy(entry->digest, digest, IMA_DIGEST_SIZE);
+
+ err = ima_add_measure_entry(entry);
+ if (err < 0) {
+ kfree(entry);
+ if (err != -EEXIST)
+ ima_error("Error adding measurement entry");
+ }
+}
Index: linux-2.6.21-rc3-mm2/security/evm/ima/ima_queue.c
===================================================================
--- /dev/null
+++ linux-2.6.21-rc3-mm2/security/evm/ima/ima_queue.c
@@ -0,0 +1,128 @@
+/*
+ * Copyright (C) 2005,2006,2007 IBM Corporation
+ *
+ * Serge Hallyn <serue@us.ibm.com>
+ * Reiner Sailer <sailer@watson.ibm.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation, version 2 of the
+ * License.
+ *
+ * File: ima_queue.c
+ * implements queues that store IMA 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/module.h>
+
+#include "ima.h"
+
+struct list_head ima_measurements; /* list of all measurements */
+struct ima_h_table ima_htable; /* key: inode (before secure-hashing a file) */
+
+/* Spinlock protects list for rarely occurring, critical operations
+ * (extend, dirty-flag). For scalability, we use RCU protection during
+ * normal operation (lookup entries). */
+DEFINE_SPINLOCK(ima_queue_lock);
+
+/* 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 DECLARE_MUTEX(ima_extend_list_mutex);
+
+void create_htable(void)
+{
+ int i;
+
+ spin_lock(&ima_queue_lock);
+ INIT_LIST_HEAD(&ima_measurements);
+ atomic_set(&ima_htable.len, 0);
+ atomic_set(&ima_htable.violations, 0);
+ ima_htable.max_htable_size = MEASURE_HTABLE_SIZE;
+
+ for (i = 0; i < ima_htable.max_htable_size; i++) {
+ INIT_HLIST_HEAD(&ima_htable.queue[i]);
+ atomic_set(&ima_htable.queue_len[i], 0);
+ }
+
+ init_MUTEX(&ima_extend_list_mutex);
+ spin_unlock(&ima_queue_lock);
+}
+
+struct queue_entry *ima_lookup_digest_entry(u8 * digest_value)
+{
+ struct queue_entry *qe, *ret = NULL;
+ unsigned int key;
+ struct hlist_node *pos;
+
+ key = HASH_KEY(digest_value);
+ rcu_read_lock();
+ hlist_for_each_entry_rcu(qe, pos, &ima_htable.queue[key], hnext) {
+ if (memcmp(qe->entry->digest, digest_value, 20) == 0) {
+ ret = qe;
+ break;
+ }
+ }
+ rcu_read_unlock();
+ return ret;
+}
+
+/* Called with ima_queue_lock held */
+static int ima_add_digest_entry(struct measure_entry *entry)
+{
+ struct queue_entry *qe;
+ unsigned int key;
+
+ key = HASH_KEY(entry->digest);
+ qe = kmalloc(sizeof(struct queue_entry), GFP_ATOMIC);
+ if (qe == NULL) {
+ ima_error("OUT OF MEMORY ERROR creating queue entry.\n");
+ return -ENOMEM;
+ }
+ qe->entry = entry;
+
+ hlist_add_head_rcu(&qe->hnext, &ima_htable.queue[key]);
+ atomic_inc(&ima_htable.queue_len[key]);
+ return 0;
+}
+
+int ima_add_measure_entry(struct measure_entry *entry)
+{
+ struct queue_entry *qe;
+ int error = 0;
+
+ down(&ima_extend_list_mutex);
+ spin_lock(&ima_queue_lock);
+ if (ima_lookup_digest_entry(entry->digest)) {
+ error = -EEXIST;
+ spin_unlock(&ima_queue_lock);
+ goto out;
+ }
+ qe = kmalloc(sizeof(struct queue_entry), GFP_ATOMIC);
+ if (qe == NULL) {
+ ima_error("OUT OF MEMORY in %s.\n", __func__);
+ error = -ENOMEM;
+ spin_unlock(&ima_queue_lock);
+ goto out;
+ }
+ qe->entry = entry;
+
+ INIT_LIST_HEAD(&qe->later);
+ list_add_tail_rcu(&qe->later, &ima_measurements);
+
+ atomic_inc(&ima_htable.len);
+ if (ima_add_digest_entry(entry)) {
+ error = -ENOMEM;
+ spin_unlock(&ima_queue_lock);
+ goto out;
+ }
+ spin_unlock(&ima_queue_lock);
+ ima_extend(entry->digest);
+ out:
+ up(&ima_extend_list_mutex);
+ return error;
+}




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