| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-Id: <1182199326.8577.6.camel@localhost.localdomain>
Date: Mon, 18 Jun 2007 16:42:06 -0400
From: Mimi Zohar <zohar@...ux.vnet.ibm.com>
To: linux-kernel@...r.kernel.org
Cc: safford@...son.ibm.com, serue@...ux.vnet.ibm.com, zohar@...ibm.com
Subject: [RFC][Patch 2/3]integrity: IMA as an integrity service provider
This is a re-release of Integrity Measurement Architecture(IMA) as
a standalone method of providing support for the Linunx Integrity
Module(LIM) 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. (Refer to
http://trousers.sourceforge.net package for TPM userspace utilities.)
IMA can be included or excluded in the kernel configuration. If
included in the kernel and the IMA_BOOTPARAM is selected, IMA can
also be enabled/disabled on the kernel command line with 'ima='.
The mtime is currently not being updated promptly for mmapped files.
There are currently two proposals to resolve this problem. When it
is fixed, performance will be substantially be improved.
Signed-off-by: Mimi Zohar <zohar@...ibm.com>
---
Index: linux-2.6.22-rc4-mm2/security/Kconfig
===================================================================
--- linux-2.6.22-rc4-mm2.orig/security/Kconfig
+++ linux-2.6.22-rc4-mm2/security/Kconfig
@@ -46,6 +46,7 @@ config INTEGRITY
configured into your kernel.
If you are unsure how to answer this question, answer N.
+source security/ima/Kconfig
config SECURITY
bool "Enable different security models"
Index: linux-2.6.22-rc4-mm2/security/Makefile
===================================================================
--- linux-2.6.22-rc4-mm2.orig/security/Makefile
+++ linux-2.6.22-rc4-mm2/security/Makefile
@@ -13,6 +13,7 @@ endif
# Object file lists
obj-$(CONFIG_SECURITY) += security.o dummy.o inode.o
obj-$(CONFIG_INTEGRITY) += integrity.o integrity_dummy.o
+obj-$(CONFIG_IMA_MEASURE) += ima/
# Must precede capability.o in order to stack properly.
obj-$(CONFIG_SECURITY_SELINUX) += selinux/built-in.o
obj-$(CONFIG_SECURITY_CAPABILITIES) += commoncap.o capability.o
Index: linux-2.6.22-rc4-mm2/fs/sysfs/mount.c
===================================================================
--- linux-2.6.22-rc4-mm2.orig/fs/sysfs/mount.c
+++ linux-2.6.22-rc4-mm2/fs/sysfs/mount.c
@@ -6,15 +6,13 @@
#include <linux/fs.h>
#include <linux/mount.h>
+#include <linux/magic.h>
#include <linux/pagemap.h>
#include <linux/init.h>
#include <asm/semaphore.h>
#include "sysfs.h"
-/* Random magic number */
-#define SYSFS_MAGIC 0x62656572
-
struct vfsmount *sysfs_mount;
struct super_block * sysfs_sb = NULL;
struct kmem_cache *sysfs_dir_cachep;
Index: linux-2.6.22-rc4-mm2/include/linux/magic.h
===================================================================
--- linux-2.6.22-rc4-mm2.orig/include/linux/magic.h
+++ linux-2.6.22-rc4-mm2/include/linux/magic.h
@@ -21,6 +21,7 @@
#define MINIX2_SUPER_MAGIC 0x2468 /* minix V2 fs */
#define MINIX2_SUPER_MAGIC2 0x2478 /* minix V2 fs, 30 char names */
#define MINIX3_SUPER_MAGIC 0x4d5a /* minix V3 fs */
+#define SYSFS_MAGIC 0x62656572
#define MSDOS_SUPER_MAGIC 0x4d44 /* MD */
#define NCP_SUPER_MAGIC 0x564c /* Guess, what 0x564c is :-) */
Index: linux-2.6.22-rc4-mm2/security/ima/Kconfig
===================================================================
--- /dev/null
+++ linux-2.6.22-rc4-mm2/security/ima/Kconfig
@@ -0,0 +1,62 @@
+#
+# IBM Integrity Measurement Architecture
+#
+
+config IMA_MEASURE
+ bool "TCG run-time Integrity Measurement Architecture(IMA)"
+ depends on INTEGRITY
+ depends on ACPI
+ select CRYPTO
+ select CRYPTO_HMAC
+ select CRYPTO_MD5
+ select CRYPTO_SHA1
+ select TCG_TPM
+ 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_BOOTPARAM
+ bool "IMA boot parameter"
+ depends on IMA_MEASURE
+ default n
+ help
+ This option adds a kernel parameter 'ima', which allows IMA
+ to be disabled at boot. If this option is selected, IMA
+ functionality can be disabled with ima=0 on the kernel
+ command line. The purpose of this option is to allow a single
+ kernel image to be distributed with IMA built in, but not
+ necessarily enabled.
+
+ If you are unsure how to answer this question, answer N.
+
+config IMA_BOOTPARAM_VALUE
+ int "IMA boot parameter default value"
+ depends on IMA_BOOTPARAM
+ range 0 1
+ default 0
+ help
+ This option sets the default value for the kernel parameter
+ 'ima=', which allows IMA to be disabled at boot. If this
+ option is set to 0 (zero), the IMA kernel parameter will
+ default to 0, disabling IMA at bootup. If this option is
+ set to 1 (one), the IMA kernel parameter will default to 1,
+ enabling IMA at bootup.
+
+ If you are unsure how to answer this question, answer 0.
+
+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.
+
Index: linux-2.6.22-rc4-mm2/security/ima/Makefile
===================================================================
--- /dev/null
+++ linux-2.6.22-rc4-mm2/security/ima/Makefile
@@ -0,0 +1,6 @@
+
+obj-$(CONFIG_IMA_MEASURE) += ima.o
+
+ifeq ($(CONFIG_IMA_MEASURE), y)
+ima-y := ima_fs.o ima_queue.o ima_init.o ima_main.o ima_crypto.o
+endif
Index: linux-2.6.22-rc4-mm2/security/ima/ima.h
===================================================================
--- /dev/null
+++ linux-2.6.22-rc4-mm2/security/ima/ima.h
@@ -0,0 +1,107 @@
+/*
+ * Copyright (C) 2005,2006,2007 IBM Corporation
+ *
+ * Reiner Sailer <sailer@...son.ibm.com>
+ *
+ * IBM Integrity Measurement Architecture
+ *
+ * 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 IMA_EVENT_NAME_LEN_MAX 255
+
+#define IMA_HASH_BITS 9
+#define IMA_MEASURE_HTABLE_SIZE (1 << IMA_HASH_BITS)
+#define IMA_HASH_KEY(digest) (hash_long( \
+ (unsigned long)(*digest), IMA_HASH_BITS));
+
+/* set during initialization */
+extern int ima_used_chip;
+extern char *ima_hash;
+
+struct ima_measure_entry {
+ u32 measure_flags;
+ u8 digest[IMA_DIGEST_SIZE]; /* sha1 or md5 measurement hash */
+ char file_name[IMA_EVENT_NAME_LEN_MAX + 1]; /* name + \0 */
+};
+
+struct ima_queue_entry {
+ struct hlist_node hnext; /* place in hash collision list */
+ struct list_head later; /* place in ima_measurements list */
+ struct ima_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 ima_create_htable(void);
+int ima_add_measure_entry(struct ima_measure_entry *entry);
+struct ima_queue_entry *ima_lookup_digest_entry(u8 * digest);
+int ima_init(void);
+void ima_cleanup(void);
+int ima_calc_hash(struct dentry *dentry, struct file *file, char *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[IMA_MEASURE_HTABLE_SIZE];
+ atomic_t queue_len[IMA_MEASURE_HTABLE_SIZE];
+};
+extern struct ima_h_table ima_htable;
+
+/* TPM "Glue" definitions */
+
+#define IMA_TPM ((((u32)TPM_ANY_TYPE)<<16)| (u32)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-2.6.22-rc4-mm2/security/ima/ima_crypto.c
===================================================================
--- /dev/null
+++ linux-2.6.22-rc4-mm2/security/ima/ima_crypto.c
@@ -0,0 +1,115 @@
+/*
+ * ima_crypto.c
+ *
+ * Calculate a file's hash.
+ *
+ * Copyright (C) 2005,2006,2007 IBM Corporation
+ * Author: Mimi Zohar <zohar@...ibm.com>
+ * Kylene Hall <kjhall@...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.
+ */
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/file.h>
+#include <linux/fs.h>
+#include <linux/crypto.h>
+#include <linux/mm.h>
+#include <asm/scatterlist.h>
+#include "ima.h"
+
+static int update_file_hash(struct dentry *dentry, struct file *f,
+ struct hash_desc *desc)
+{
+ struct file *file = f;
+ struct scatterlist sg[1];
+ loff_t i_size;
+ int error = 0;
+
+ char *rbuf = NULL;
+ int rbuf_len = 0;
+ int offset = 0;
+
+ if (!file) {
+ struct dentry *de = dget(dentry);
+ if (!de)
+ goto out;
+
+ file = dentry_open(de, NULL, O_RDONLY);
+ if (IS_ERR(file)) {
+ printk(KERN_INFO "%s: dentry_open failed\n",
+ __FUNCTION__);
+ error = -ENOENT;
+ dput(de);
+ file = NULL;
+ goto out;
+ }
+ }
+
+ if (!file || !file->f_dentry || !file->f_dentry->d_inode) {
+ printk(KERN_INFO "%s: missing file\n", __FUNCTION__);
+ goto out;
+ }
+
+ rbuf = kzalloc(PAGE_SIZE, GFP_KERNEL);
+ if (!rbuf) {
+ error = -ENOMEM;
+ goto out;
+ }
+ i_size = i_size_read(file->f_dentry->d_inode);
+ while (offset < i_size) {
+ rbuf_len = kernel_read(file, offset, rbuf, PAGE_SIZE);
+ if (rbuf_len <= 0)
+ break;
+ offset += rbuf_len;
+ sg[0].page = virt_to_page(rbuf);
+ sg[0].offset = ((long)rbuf & ~PAGE_MASK);
+ sg[0].length = rbuf_len;
+
+ error = crypto_hash_update(desc, sg, rbuf_len);
+ if (error)
+ break;
+ }
+
+ kfree(rbuf);
+out:
+ if (file && !f)
+ fput(file); /* clean up dentry_open() */
+ return error;
+}
+
+/*
+ * Calculate the MD5/SHA1 digest
+ */
+int ima_calc_hash(struct dentry *dentry, struct file *file, char *digest)
+{
+ struct crypto_hash *tfm;
+ struct hash_desc desc;
+ int error = 0;
+
+ if (!dentry && !file)
+ return -ENOENT;
+
+ tfm = crypto_alloc_hash(ima_hash, 0, CRYPTO_ALG_ASYNC);
+ if (IS_ERR(tfm)) {
+ printk(KERN_INFO "%s: failed to load %s transform: %ld\n",
+ __FUNCTION__, ima_hash, PTR_ERR(tfm));
+ return -ENOSYS;
+ }
+ desc.tfm = tfm;
+ desc.flags = 0;
+ error = crypto_hash_init(&desc);
+ if (error)
+ goto out;
+
+ error = update_file_hash(dentry, file, &desc);
+ if (!error)
+ error = crypto_hash_final(&desc, digest);
+
+out:
+ crypto_free_hash(tfm);
+ return error;
+}
Index: linux-2.6.22-rc4-mm2/security/ima/ima_fs.c
===================================================================
--- /dev/null
+++ linux-2.6.22-rc4-mm2/security/ima/ima_fs.c
@@ -0,0 +1,275 @@
+/*
+ * Copyright (C) 2005,2006,2007 IBM Corporation
+ *
+ * Kylene Hall <kjhall@...ibm.com>
+ * Reiner Sailer <sailer@...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 ima_queue_entry *qe;
+ struct ima_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 ima_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 > IMA_EVENT_NAME_LEN_MAX)
+ filename_len = IMA_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 ima_queue_entry *qe;
+ struct ima_measure_entry *e;
+ int i;
+
+ /* get entry */
+ qe = list_entry(lpos, struct ima_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;
+static struct dentry *binary_runtime_measurements;
+static struct dentry *ascii_runtime_measurements;
+static struct dentry *runtime_measurements_count;
+static struct dentry *violations;
+
+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-2.6.22-rc4-mm2/security/ima/ima_init.c
===================================================================
--- /dev/null
+++ linux-2.6.22-rc4-mm2/security/ima/ima_init.c
@@ -0,0 +1,116 @@
+/*
+ * Copyright (C) 2005,2006,2007 IBM Corporation
+ *
+ * Reiner Sailer <sailer@...son.ibm.com>
+ * Leendert van Doorn <leendert@...son.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"
+
+/* 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];
+
+int ima_used_chip;
+
+/* general invalidation function called by the measurement code */
+static 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 */
+}
+
+static void ima_add_boot_aggregate(void)
+{
+ /* cumulative sha1 over tpm registers 0-7 */
+ struct ima_measure_entry *entry;
+ size_t count;
+ int err;
+
+ /* create new entry for boot aggregate */
+ entry = kzalloc(sizeof(struct ima_measure_entry), GFP_ATOMIC);
+ if (entry == NULL) {
+ ima_invalidate_pcr("error allocating new measurement entry");
+ return;
+ }
+ if ((count = strlen(boot_aggregate_name)) > IMA_EVENT_NAME_LEN_MAX)
+ count = IMA_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");
+ }
+}
+
+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);
+
+ ima_create_htable(); /* for measurements */
+
+ /* boot aggregate must be very first entry */
+ ima_add_boot_aggregate();
+
+ return ima_fs_init();
+}
+
+void __exit ima_cleanup(void)
+{
+ ima_fs_cleanup();
+}
Index: linux-2.6.22-rc4-mm2/security/ima/ima_main.c
===================================================================
--- /dev/null
+++ linux-2.6.22-rc4-mm2/security/ima/ima_main.c
@@ -0,0 +1,364 @@
+/*
+ * Copyright (C) 2005,2006,2007 IBM Corporation
+ *
+ * Authors:
+ * Reiner Sailer <sailer@...son.ibm.com>
+ * Serge Hallyn <serue@...ibm.com>
+ * Kylene Hall <kylene@...ibm.com>
+ * Mimi Zohar <zohar@...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 <linux/integrity.h>
+#include <linux/magic.h>
+#include <linux/writeback.h>
+
+#include "ima.h"
+
+#define SHA1_DIGEST_SIZE 20 /* SHA1 is 160-bits */
+
+struct ima_iint_cache {
+ struct timespec mtime;
+ int measured;
+ struct mutex mutex;
+};
+
+#ifdef CONFIG_IMA_BOOTPARAM
+static int ima_enabled = CONFIG_IMA_BOOTPARAM_VALUE;
+
+static int __init ima_enabled_setup(char *str)
+{
+ ima_enabled = simple_strtol(str, NULL, 0);
+ return 1;
+}
+
+__setup("ima=", ima_enabled_setup);
+#else
+static int ima_enabled = 1;
+#endif
+
+char *ima_hash = "sha1";
+static int __init hash_setup(char *str)
+{
+ if (strncmp(str, "md5", 3) == 0)
+ ima_hash = str;
+ else if (strncmp(str, "sha1", 4) != 0)
+ printk(KERN_INFO "%s: invalid hash type %s, using sha1\n",
+ __FUNCTION__, str);
+ return 1;
+}
+
+__setup("ima_hash=", hash_setup);
+
+/*
+ * ima_add_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
+ *
+ * Description:ima_add_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.
+ */
+static void ima_add_measure(const unsigned char *name, int hash_len, char *hash)
+{
+ struct ima_measure_entry *entry;
+ u8 digest[IMA_DIGEST_SIZE];
+ int err = 0, count;
+ struct ima_queue_entry *qe;
+
+ if (hash_len > IMA_DIGEST_SIZE) {
+ ima_info("%s: 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? */
+ qe = ima_lookup_digest_entry(digest);
+ if (qe) {
+ printk(KERN_INFO "%s: %s hash exists(%s)\n",
+ __FUNCTION__, name, qe->entry->file_name);
+ return;
+ }
+
+ /* create new entry and add to measurement list */
+ entry = kzalloc(sizeof(struct ima_measure_entry), GFP_ATOMIC);
+ if (!entry) {
+ ima_error("Error allocating new measurement entry");
+ return; /* invalidate pcr */
+ }
+
+ entry->measure_flags = 0;
+ if (!name) {
+ printk(KERN_INFO "%s: name is null\n", __FUNCTION__);
+ count = 1;
+ } else {
+ if ((count = strlen(name)) > IMA_EVENT_NAME_LEN_MAX)
+ count = IMA_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");
+ }
+}
+
+/* what could we exclude
+ * - non-executable/non-library files ?
+ * - /proc /dev ?
+ * Only measure files opened for read-only or execute
+ */
+static int skip_measurement(struct inode *inode, int mask)
+{
+ if ((inode->i_sb->s_magic == PROC_SUPER_MAGIC) ||
+ (inode->i_sb->s_magic == SYSFS_MAGIC)) {
+ return 1; /*can't measure */
+ }
+ if (special_file(inode->i_mode) || S_ISLNK(inode->i_mode))
+ return 1; /* don't measure */
+
+ if (S_ISREG(inode->i_mode)
+ && ((mask == MAY_READ) || (mask == MAY_EXEC))
+ && (mask != MAY_WRITE) && (mask != MAY_APPEND))
+ return 0; /* measure */
+ return 1; /* don't measure */
+}
+
+/*
+ * Must be called with the dentry, as opposed to the inode, as we need to be
+ * able to open the file, using dentry_open(), in order to calculate the hash.
+ */
+static void ima_measure(struct dentry *dentry, struct file *file,
+ const unsigned char *filename, int mask)
+{
+ struct inode *inode = NULL;
+ struct ima_iint_cache *iint;
+
+ if (!ima_enabled)
+ return;
+
+ if (!dentry && (!file || !file->f_dentry))
+ return;
+
+ if (file && file->f_dentry && file->f_dentry->d_inode)
+ inode = file->f_dentry->d_inode;
+ else if (dentry && dentry->d_inode)
+ inode = dentry->d_inode;
+
+ if (!inode)
+ return;
+
+ if (skip_measurement(inode, mask))
+ return;
+
+ iint = inode->i_integrity;
+ mutex_lock(&iint->mutex);
+ if (!iint->measured) {
+ char hash[SHA1_DIGEST_SIZE];
+ int rc;
+
+ memset(hash, 0, SHA1_DIGEST_SIZE);
+ rc = ima_calc_hash(dentry, file, hash);
+ if (!rc) {
+ ima_add_measure(filename, SHA1_DIGEST_SIZE, hash);
+ iint->measured = 1;
+ }
+ }
+ mutex_unlock(&iint->mutex);
+ return;
+}
+
+/*
+ * When files are opened/closed in quick succession, the mtime
+ * might not be granular enough, resulting in the mtime remaining
+ * unchanged.
+ *
+ * Use to prevent changes from not being detected.
+ */
+static inline int timespec_recent(struct timespec *a)
+{
+ return CURRENT_TIME.tv_sec - a->tv_sec <= 1 ? 1 : 0;
+}
+
+static inline void timespec_set(struct timespec *to, struct timespec *from)
+{
+ to->tv_sec = from->tv_sec;
+ to->tv_nsec = from->tv_nsec;
+}
+
+/*
+ * Called on close
+ * - If a file changes, mark it as not having been measured.
+ */
+static void ima_file_free(struct file *file)
+{
+ struct inode *inode = NULL;
+ struct ima_iint_cache *iint;
+
+ if (!file->f_dentry) /* can be NULL */
+ return;
+
+ inode = file->f_dentry->d_inode;
+ if (S_ISDIR(inode->i_mode))
+ return;
+ if ((file->f_mode & FMODE_WRITE) &&
+ (atomic_read(&inode->i_writecount) == 1)) {
+ iint = inode->i_integrity;
+ mutex_lock(&iint->mutex);
+ /* The mtime is currently not being updated promptly
+ * for mapped files. When fixed, for performance
+ * improvement uncomment the following lines.
+ */
+ //if ((!timespec_equal(&iint->mtime, &inode->i_mtime))
+ // || timespec_recent(&iint->mtime))
+ // iint->measured = 0;
+ iint->measured = 0;
+ mutex_unlock(&iint->mutex);
+ }
+}
+
+/*
+ * Indicate a new file
+ */
+static void ima_inode_init(struct inode *inode, struct inode *dir,
+ char **name, void **value, size_t * len)
+{
+ struct ima_iint_cache *iint = inode->i_integrity;
+
+ mutex_lock(&iint->mutex);
+ iint->mtime.tv_sec = 0;
+ mutex_unlock(&iint->mutex);
+ return;
+}
+
+static struct ima_iint_cache *ima_alloc_integrity(void)
+{
+ struct ima_iint_cache *iint;
+
+ iint = kzalloc(sizeof(struct ima_iint_cache), GFP_KERNEL);
+ if (!iint)
+ return NULL;
+
+ mutex_init(&iint->mutex);
+ return iint;
+}
+
+static int ima_inode_alloc_integrity(struct inode *inode)
+{
+ struct ima_iint_cache *iint;
+
+ iint = ima_alloc_integrity();
+ if (!iint)
+ return -ENOMEM;
+
+ inode->i_integrity = iint;
+ timespec_set(&iint->mtime, &inode->i_mtime);
+ return 0;
+}
+
+static void ima_inode_free_integrity(struct inode *inode)
+{
+ struct ima_iint_cache *iint = inode->i_integrity;
+
+ if (iint) {
+ inode->i_integrity = NULL;
+ kfree(iint);
+ }
+}
+
+/*
+ * For all inodes allocate inode->i_integrity(iint), before the integrity
+ * subsystem is enabled.
+ */
+static void ima_fixup_inodes(void)
+{
+ struct super_block *sb;
+
+ spin_lock(&sb_lock);
+ list_for_each_entry(sb, &super_blocks, s_list) {
+ struct inode *inode;
+
+ spin_unlock(&sb_lock);
+
+ spin_lock(&inode_lock);
+ list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
+ spin_unlock(&inode_lock);
+
+ spin_lock(&inode->i_lock);
+ if (!inode->i_integrity)
+ ima_inode_alloc_integrity(inode);
+ spin_unlock(&inode->i_lock);
+
+ spin_lock(&inode_lock);
+ }
+ spin_unlock(&inode_lock);
+
+ spin_lock(&sb_lock);
+ }
+ spin_unlock(&sb_lock);
+}
+
+static struct integrity_operations ima_integrity_ops = {
+ .measure = ima_measure,
+ .inode_init_integrity = ima_inode_init,
+ .inode_alloc_integrity = ima_inode_alloc_integrity,
+ .inode_free_integrity = ima_inode_free_integrity,
+ .file_free_integrity = ima_file_free
+};
+
+static struct crypto_hash *tfm_hash; /* preload crypto alg */
+static int __init init_ima(void)
+{
+ int error;
+ tfm_hash = crypto_alloc_hash(ima_hash, 0, CRYPTO_ALG_ASYNC);
+
+ error = ima_init();
+ if (error)
+ goto out;
+ ima_fixup_inodes();
+ error = register_integrity(&ima_integrity_ops);
+out:
+ return error;
+}
+
+static void __exit cleanup_ima(void)
+{
+ unregister_integrity(&ima_integrity_ops);
+ ima_cleanup();
+ crypto_free_hash(tfm_hash);
+}
+
+late_initcall(init_ima);
+module_exit(cleanup_ima);
+
+MODULE_DESCRIPTION("Integrity Measurement Architecture");
+MODULE_LICENSE("GPL");
Index: linux-2.6.22-rc4-mm2/security/ima/ima_queue.c
===================================================================
--- /dev/null
+++ linux-2.6.22-rc4-mm2/security/ima/ima_queue.c
@@ -0,0 +1,116 @@
+/*
+ * Copyright (C) 2005,2006,2007 IBM Corporation
+ *
+ * Serge Hallyn <serue@...ibm.com>
+ * Reiner Sailer <sailer@...son.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) */
+
+/* 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);
+
+void ima_create_htable(void)
+{
+ int i;
+
+ INIT_LIST_HEAD(&ima_measurements);
+ atomic_set(&ima_htable.len, 0);
+ atomic_set(&ima_htable.violations, 0);
+ ima_htable.max_htable_size = IMA_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);
+ }
+
+ mutex_init(&ima_extend_list_mutex);
+}
+
+struct ima_queue_entry *ima_lookup_digest_entry(u8 * digest_value)
+{
+ struct ima_queue_entry *qe, *ret = NULL;
+ unsigned int key;
+ struct hlist_node *pos;
+
+ key = IMA_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 mutex held */
+static int ima_add_digest_entry(struct ima_measure_entry *entry)
+{
+ struct ima_queue_entry *qe;
+ unsigned int key;
+
+ key = IMA_HASH_KEY(entry->digest);
+ qe = kmalloc(sizeof(struct ima_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 ima_measure_entry *entry)
+{
+ struct ima_queue_entry *qe;
+ int error = 0;
+
+ mutex_lock(&ima_extend_list_mutex);
+ if (ima_lookup_digest_entry(entry->digest)) {
+ error = -EEXIST;
+ goto out;
+ }
+ qe = kmalloc(sizeof(struct ima_queue_entry), GFP_ATOMIC);
+ if (qe == NULL) {
+ ima_error("OUT OF MEMORY in %s.\n", __func__);
+ error = -ENOMEM;
+ 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;
+ goto out;
+ }
+ ima_extend(entry->digest);
+out:
+ mutex_unlock(&ima_extend_list_mutex);
+ return error;
+}
Index: linux-2.6.22-rc4-mm2/Documentation/kernel-parameters.txt
===================================================================
--- linux-2.6.22-rc4-mm2.orig/Documentation/kernel-parameters.txt
+++ linux-2.6.22-rc4-mm2/Documentation/kernel-parameters.txt
@@ -42,6 +42,7 @@ parameter is applicable:
FB The frame buffer device is enabled.
HW Appropriate hardware is enabled.
IA-64 IA-64 architecture is enabled.
+ IMA Integrity measurement architecture is enabled.
IOSCHED More than one I/O scheduler is enabled.
IP_PNP IP DHCP, BOOTP, or RARP is enabled.
ISAPNP ISA PnP code is enabled.
@@ -760,6 +761,17 @@ and is between 256 and 4096 characters.
ihash_entries= [KNL]
Set number of hash buckets for inode cache.
+ ima= [IMA] Disable or enable IMA at boot time.
+ Format: { "0" | "1" }
+ See security/ima/Kconfig help text.
+ 0 -- disable.
+ 1 -- enable.
+ Default value is set via kernel config option.
+
+ ima_hash= [IMA] runtime ability to define hash crypto alg.
+ Format: { "MD5" | "SHA1" }
+ Default is "SHA1".
+
in2000= [HW,SCSI]
See header of drivers/scsi/in2000.c.
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists