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    SubjectRe: [PATCH 2/6] integrity: IMA as an integrity service provider
    Quoting Mimi Zohar (zohar@linux.vnet.ibm.com):
    > IMA provides hardware (TPM) based measurement and attestation for
    > file measurements. As the Trusted Computing (TPM) model requires,
    > IMA measures all files before they are accessed in any way (on the
    > integrity_bprm_check, integrity_path_check and integrity_file_mmap
    > hooks), and commits the measurements to the TPM. Once added to the
    > TPM, measurements can not be removed.
    >
    > In addition, IMA maintains a list of these file measurements, which
    > can be used to validate the aggregate value stored in the TPM. The
    > TPM can sign these measurements, and thus the system can prove, to
    > itself and to a third party, the system's integrity in a way that
    > cannot be circumvented by malicious or compromised software.
    >
    > - removed LIM hooks and API registration; IMA is now called directly
    > - added slab for integrity information(iint) associated with an inode
    > - added a local read and write count in iint
    > - lots of code refactoring (i.e. calculating the boot aggregate,
    > flagging openwriters/ToMToU)
    > - statically defined and initialized variables
    > - addressed the credential merge changes
    > - addressed locking issues in general (i.e. ima_file_free())
    > and addressed the rcu-locking problem in ima_iint_delete() in particular
    > - removed caching of measurement policy results
    > - removed Kconfig prompt for: pcr index, informational audit messages
    >
    > Signed-off-by: Mimi Zohar <zohar@us.ibm.com>

    I notice there is no MAINTAINERS entry for IMA?

    A few comments below. Aside from my comments in ima_bprm_check and
    ima_path_check,

    Acked-by: Serge Hallyn <serue@us.ibm.com>

    > ---
    > diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
    > index 40c51e9..8cc40a1 100644
    > --- a/Documentation/kernel-parameters.txt
    > +++ b/Documentation/kernel-parameters.txt
    > @@ -901,6 +901,15 @@ and is between 256 and 4096 characters. It is defined in the file
    > ihash_entries= [KNL]
    > Set number of hash buckets for inode cache.
    >
    > + ima_audit= [IMA]
    > + Format: { "0" | "1" }
    > + 0 -- integrity auditing messages. (Default)
    > + 1 -- enable informational integrity auditing messages.
    > +
    > + ima_hash= [IMA]
    > + Formt: { "sha1" | "md5" }
    > + default: "sha1"
    > +
    > in2000= [HW,SCSI]
    > See header of drivers/scsi/in2000.c.
    >
    > diff --git a/include/linux/audit.h b/include/linux/audit.h
    > index 67e5dbf..930939a 100644
    > --- a/include/linux/audit.h
    > +++ b/include/linux/audit.h
    > @@ -125,6 +125,11 @@
    > #define AUDIT_LAST_KERN_ANOM_MSG 1799
    > #define AUDIT_ANOM_PROMISCUOUS 1700 /* Device changed promiscuous mode */
    > #define AUDIT_ANOM_ABEND 1701 /* Process ended abnormally */
    > +#define AUDIT_INTEGRITY_DATA 1800 /* Data integrity verification */
    > +#define AUDIT_INTEGRITY_METADATA 1801 /* Metadata integrity verification */
    > +#define AUDIT_INTEGRITY_STATUS 1802 /* Integrity enable status */
    > +#define AUDIT_INTEGRITY_HASH 1803 /* Integrity HASH type */
    > +#define AUDIT_INTEGRITY_PCR 1804 /* PCR invalidation msgs */
    >
    > #define AUDIT_KERNEL 2000 /* Asynchronous audit record. NOT A REQUEST. */
    >
    > diff --git a/include/linux/ima.h b/include/linux/ima.h
    > index 4ed1e4d..dcc3664 100644
    > --- a/include/linux/ima.h
    > +++ b/include/linux/ima.h
    > @@ -12,6 +12,15 @@
    > #ifndef _LINUX_IMA_H
    > #define _LINUX_IMA_H
    >
    > +#ifdef CONFIG_IMA
    > +extern int ima_bprm_check(struct linux_binprm *bprm);
    > +extern int ima_inode_alloc(struct inode *inode);
    > +extern void ima_inode_free(struct inode *inode);
    > +extern int ima_path_check(struct path *path, int mask);
    > +extern void ima_file_free(struct file *file);
    > +extern int ima_file_mmap(struct file *file, unsigned long prot);
    > +
    > +#else
    > static inline int ima_bprm_check(struct linux_binprm *bprm)
    > {
    > return 0;
    > @@ -41,4 +50,5 @@ static inline int ima_file_mmap(struct file *file, unsigned long prot)
    > {
    > return 0;
    > }
    > +#endif /* CONFIG_IMA_H */
    > #endif /* _LINUX_IMA_H */
    > diff --git a/security/Kconfig b/security/Kconfig
    > index 9438535..bf129f8 100644
    > --- a/security/Kconfig
    > +++ b/security/Kconfig
    > @@ -55,7 +55,8 @@ config SECURITYFS
    > bool "Enable the securityfs filesystem"
    > help
    > This will build the securityfs filesystem. It is currently used by
    > - the TPM bios character driver. It is not used by SELinux or SMACK.
    > + the TPM bios character driver and IMA, an integrity provider. It is
    > + not used by SELinux or SMACK.
    >
    > If you are unsure how to answer this question, answer N.
    >
    > @@ -135,5 +136,7 @@ config SECURITY_DEFAULT_MMAP_MIN_ADDR
    > source security/selinux/Kconfig
    > source security/smack/Kconfig
    >
    > +source security/integrity/ima/Kconfig
    > +
    > endmenu
    >
    > diff --git a/security/Makefile b/security/Makefile
    > index c05c127..595536c 100644
    > --- a/security/Makefile
    > +++ b/security/Makefile
    > @@ -17,3 +17,7 @@ obj-$(CONFIG_SECURITY_SELINUX) += selinux/built-in.o
    > obj-$(CONFIG_SECURITY_SMACK) += smack/built-in.o
    > obj-$(CONFIG_SECURITY_ROOTPLUG) += root_plug.o
    > obj-$(CONFIG_CGROUP_DEVICE) += device_cgroup.o
    > +
    > +# Object integrity file lists
    > +subdir-$(CONFIG_IMA) += integrity/ima
    > +obj-$(CONFIG_IMA) += integrity/ima/built-in.o
    > diff --git a/security/integrity/ima/Kconfig b/security/integrity/ima/Kconfig
    > new file mode 100644
    > index 0000000..2a761c8
    > --- /dev/null
    > +++ b/security/integrity/ima/Kconfig
    > @@ -0,0 +1,49 @@
    > +# IBM Integrity Measurement Architecture
    > +#
    > +config IMA
    > + bool "Integrity Measurement Architecture(IMA)"
    > + depends on ACPI
    > + select SECURITYFS
    > + select CRYPTO
    > + select CRYPTO_HMAC
    > + select CRYPTO_MD5
    > + select CRYPTO_SHA1
    > + select TCG_TPM
    > + select TCG_TIS
    > + help
    > + The Trusted Computing Group(TCG) runtime Integrity
    > + Measurement Architecture(IMA) maintains a list of hash
    > + values of executables and other sensitive system files,
    > + as they are read or executed. If an attacker manages
    > + to change the contents of an important system file
    > + being measured, we can tell.
    > +
    > + If your system has a TPM chip, then IMA also maintains
    > + an aggregate integrity value over this list inside the
    > + TPM hardware, so that the TPM can prove to a third party
    > + whether or not critical system files have been modified.
    > + Read <http://www.usenix.org/events/sec04/tech/sailer.html>
    > + to learn more about IMA.
    > + If unsure, say N.
    > +
    > +config IMA_MEASURE_PCR_IDX
    > + int
    > + depends on IMA
    > + 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.
    > +
    > +config IMA_AUDIT
    > + bool
    > + depends on IMA
    > + default y
    > + help
    > + This option adds a kernel parameter 'ima_audit', which
    > + allows informational auditing messages to be enabled
    > + at boot. If this option is selected, informational integrity
    > + auditing messages can be enabled with 'ima_audit=1' on
    > + the kernel command line.
    > +
    > diff --git a/security/integrity/ima/Makefile b/security/integrity/ima/Makefile
    > new file mode 100644
    > index 0000000..9d6bf97
    > --- /dev/null
    > +++ b/security/integrity/ima/Makefile
    > @@ -0,0 +1,9 @@
    > +#
    > +# Makefile for building Trusted Computing Group's(TCG) runtime Integrity
    > +# Measurement Architecture(IMA).
    > +#
    > +
    > +obj-$(CONFIG_IMA) += ima.o
    > +
    > +ima-y := ima_queue.o ima_init.o ima_main.o ima_crypto.o ima_api.o \
    > + ima_policy.o ima_iint.o ima_audit.o
    > diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
    > new file mode 100644
    > index 0000000..04a397e
    > --- /dev/null
    > +++ b/security/integrity/ima/ima.h
    > @@ -0,0 +1,136 @@
    > +/*
    > + * Copyright (C) 2005,2006,2007,2008 IBM Corporation
    > + *
    > + * Authors:
    > + * Reiner Sailer <sailer@watson.ibm.com>
    > + * Mimi Zohar <zohar@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.h
    > + * internal Integrity Measurement Architecture (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>
    > +#include <linux/audit.h>
    > +
    > +enum ima_show_type { IMA_SHOW_BINARY, IMA_SHOW_ASCII };
    > +enum tpm_pcrs { TPM_PCR0 = 0, TPM_PCR8 = 8 };
    > +
    > +/* 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)
    > +
    > +/* set during initialization */
    > +extern int ima_initialized;
    > +extern int ima_used_chip;
    > +extern char *ima_hash;
    > +
    > +/* IMA inode template definition */
    > +struct ima_template_data {
    > + u8 digest[IMA_DIGEST_SIZE]; /* sha1/md5 measurement hash */
    > + char file_name[IMA_EVENT_NAME_LEN_MAX + 1]; /* name + \0 */
    > +};
    > +
    > +#define IMA_TEMPLATE_NAME_LEN_MAX 20

    No longer used

    > +struct ima_template_entry {
    > + u8 digest[IMA_DIGEST_SIZE]; /* sha1 or md5 measurement hash */
    > + char *template_name;
    > + int template_len;
    > + struct ima_template_data template;
    > +};
    > +
    > +struct ima_queue_entry {
    > + struct hlist_node hnext; /* place in hash collision list */
    > + struct list_head later; /* place in ima_measurements list */
    > + struct ima_template_entry *entry;
    > +};
    > +extern struct list_head ima_measurements; /* list of all measurements */
    > +
    > +/* declarations */
    > +void integrity_audit_msg(int audit_msgno, struct inode *inode,
    > + const unsigned char *fname, const char *op,
    > + const char *cause, int result, int info);
    > +
    > +/* Internal IMA function definitions */
    > +void ima_iintcache_init(void);
    > +int ima_init(void);
    > +int ima_add_template_entry(struct ima_template_entry *entry, int violation,
    > + const char *op, struct inode *inode);
    > +int ima_calc_hash(struct file *file, char *digest);
    > +int ima_calc_template_hash(int template_len, void *template, char *digest);
    > +int ima_calc_boot_aggregate(char *digest);
    > +void ima_add_violation(struct inode *inode, const unsigned char *filename,
    > + const char *op, const char *cause);
    > +
    > +/*
    > + * used to protect h_table and sha_table
    > + */
    > +extern spinlock_t ima_queue_lock;
    > +
    > +struct ima_h_table {
    > + atomic_long_t len; /* number of stored measurements in the list */
    > + atomic_long_t violations;
    > + struct hlist_head queue[IMA_MEASURE_HTABLE_SIZE];
    > +};
    > +extern struct ima_h_table ima_htable;
    > +
    > +static inline unsigned long ima_hash_key(u8 *digest)
    > +{
    > + return hash_long(*digest, IMA_HASH_BITS);
    > +}
    > +
    > +/* iint cache flags */
    > +#define IMA_MEASURED 1
    > +
    > +/* integrity data associated with an inode */
    > +struct ima_iint_cache {
    > + u64 version; /* track inode changes */
    > + unsigned long flags;
    > + u8 digest[IMA_DIGEST_SIZE];
    > + struct mutex mutex; /* protects: version, flags, digest */
    > + long readcount; /* measured files readcount */
    > + long writecount; /* measured files writecount */
    > + struct kref refcount; /* ima_iint_cache reference count */
    > + struct rcu_head rcu;
    > +};
    > +
    > +/* LIM API function definitions */
    > +int ima_must_measure(struct ima_iint_cache *iint, struct inode *inode,
    > + int mask, int function);
    > +int ima_collect_measurement(struct ima_iint_cache *iint, struct file *file);
    > +void ima_store_measurement(struct ima_iint_cache *iint, struct file *file,
    > + const unsigned char *filename);
    > +int ima_store_template(struct ima_template_data *data, int violation,
    > + struct inode *inode);
    > +
    > +/* radix tree calls to lookup, insert, delete
    > + * integrity data associated with an inode.
    > + */
    > +struct ima_iint_cache *ima_iint_insert(struct inode *inode);
    > +struct ima_iint_cache *ima_iint_find_get(struct inode *inode);
    > +struct ima_iint_cache *ima_iint_find_insert_get(struct inode *inode);
    > +void ima_iint_delete(struct inode *inode);
    > +void iint_free(struct kref *kref);
    > +void iint_rcu_free(struct rcu_head *rcu);
    > +
    > +/* IMA policy related functions */
    > +enum ima_hooks { PATH_CHECK = 1, FILE_MMAP, BPRM_CHECK };
    > +
    > +int ima_match_policy(struct inode *inode, enum ima_hooks func, int mask);
    > +void ima_init_policy(void);
    > +void ima_update_policy(void);
    > +#endif
    > diff --git a/security/integrity/ima/ima_api.c b/security/integrity/ima/ima_api.c
    > new file mode 100644
    > index 0000000..7c1db11
    > --- /dev/null
    > +++ b/security/integrity/ima/ima_api.c
    > @@ -0,0 +1,185 @@
    > +/*
    > + * Copyright (C) 2008 IBM Corporation
    > + *
    > + * Author: Mimi Zohar <zohar@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_api.c
    > + * Implements must_measure, collect_measurement, store_measurement,
    > + * and store_template.
    > + */
    > +#include <linux/module.h>
    > +
    > +#include "ima.h"
    > +static char *IMA_TEMPLATE_NAME = "ima";
    > +
    > +/*
    > + * ima_store_template - store ima template measurements
    > + *
    > + * Calculate the hash of a template entry, add the template entry
    > + * to an ordered list of measurement entries maintained inside the kernel,
    > + * and also update 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.
    > + *
    > + * Returns 0 on success, error code otherwise
    > + */
    > +int ima_store_template(struct ima_template_data *template,
    > + int violation, struct inode *inode)
    > +{
    > + struct ima_template_entry *entry;
    > + const char *op = "add_template_measure";
    > + const char *audit_cause = "ENOMEM";
    > + int result = -ENOMEM;
    > +
    > + entry = kmalloc(sizeof(*entry), GFP_KERNEL);
    > + if (!entry)
    > + goto err_out;
    > +
    > + memcpy(&entry->template, template, sizeof(*template));
    > + memset(&entry->digest, 0, sizeof(entry->digest));
    > + entry->template_name = IMA_TEMPLATE_NAME;
    > + entry->template_len = sizeof(*template);
    > +
    > + if (!violation) {
    > + result = ima_calc_template_hash(entry->template_len,
    > + template, entry->digest);
    > + if (result < 0) {
    > + kfree(entry);
    > + audit_cause = "hashing_error";
    > + goto err_out;
    > + }
    > + }
    > + result = ima_add_template_entry(entry, violation, op, inode);
    > + if (result < 0)
    > + kfree(entry);
    > + return result;
    > +
    > +err_out:
    > + integrity_audit_msg(AUDIT_INTEGRITY_PCR, inode, entry->template_name,
    > + op, audit_cause, result, 0);
    > +
    > + return result;
    > +}
    > +
    > +/*
    > + * ima_add_violation - add violation to measurement list.
    > + *
    > + * Violations are flagged in the measurement list with zero hash values.
    > + * By extending the PCR with 0xFF's instead of with zeroes, the PCR
    > + * value is invalidated.
    > + */
    > +void ima_add_violation(struct inode *inode, const unsigned char *filename,
    > + const char *op, const char *cause)
    > +{
    > + struct ima_template_data template;
    > + int violation = 1;
    > + int result;
    > +
    > + /* can overflow, only indicator */
    > + atomic_long_inc(&ima_htable.violations);
    > +
    > + memset(&template, 0, sizeof(template));
    > + strncpy(template.file_name, filename, IMA_EVENT_NAME_LEN_MAX);
    > + result = ima_store_template(&template, violation, inode);
    > + integrity_audit_msg(AUDIT_INTEGRITY_PCR, inode, filename,
    > + op, cause, result, 0);
    > +}
    > +
    > +/**
    > + * ima_must_measure - measure decision based on policy.
    > + * @inode: pointer to inode to measure
    > + * @mask: contains the permission mask (MAY_READ, MAY_WRITE, MAY_EXECUTE)
    > + * @function: calling function (PATH_CHECK, BPRM_CHECK, FILE_MMAP)
    > + *
    > + * The policy is defined in terms of keypairs:
    > + * subj=, obj=, type=, func=, mask=, fsmagic=
    > + * subj,obj, and type: are LSM specific.
    > + * func: PATH_CHECK | BPRM_CHECK | FILE_MMAP
    > + * mask: contains the permission mask
    > + * fsmagic: hex value
    > + *
    > + * Must be called with iint->mutex held.
    > + *
    > + * Return 0 to measure. Return 1 if already measured.
    > + * For matching a DONT_MEASURE policy, no policy, or other
    > + * error, return an error code.
    > +*/
    > +int ima_must_measure(struct ima_iint_cache *iint, struct inode *inode,
    > + int mask, int function)
    > +{
    > + int must_measure;
    > +
    > + if (iint->flags & IMA_MEASURED)
    > + return 1;
    > +
    > + must_measure = ima_match_policy(inode, function, mask);
    > + return must_measure ? 0 : -EACCES;
    > +}
    > +
    > +/*
    > + * ima_collect_measurement - collect file measurement
    > + *
    > + * Calculate the file hash, if it doesn't already exist,
    > + * storing the measurement and i_version in the iint.
    > + *
    > + * Must be called with iint->mutex held.
    > + *
    > + * Return 0 on success, error code otherwise
    > + */
    > +int ima_collect_measurement(struct ima_iint_cache *iint, struct file *file)
    > +{
    > + int result = -EEXIST;
    > +
    > + if (!(iint->flags & IMA_MEASURED)) {
    > + u64 i_version = file->f_dentry->d_inode->i_version;
    > +
    > + memset(iint->digest, 0, IMA_DIGEST_SIZE);
    > + result = ima_calc_hash(file, iint->digest);
    > + if (!result)
    > + iint->version = i_version;
    > + }
    > + return result;
    > +}
    > +
    > +/*
    > + * ima_store_measurement - store file measurement
    > + *
    > + * Create an "ima" template and then store the template by calling
    > + * ima_store_template.
    > + *
    > + * We only get here if the inode has not already been measured,
    > + * but the measurement could already exist:
    > + * - multiple copies of the same file on either the same or
    > + * different filesystems.
    > + * - the inode was previously flushed as well as the iint info,
    > + * containing the hashing info.
    > + *
    > + * Must be called with iint->mutex held.
    > + */
    > +void ima_store_measurement(struct ima_iint_cache *iint, struct file *file,
    > + const unsigned char *filename)
    > +{
    > +
    > + struct inode *inode = file->f_dentry->d_inode;
    > + struct ima_template_data template;
    > + int violation = 0;
    > + int result;
    > +
    > + memset(&template, 0, sizeof(template));
    > + memcpy(template.digest, iint->digest, IMA_DIGEST_SIZE);
    > + strncpy(template.file_name, filename, IMA_EVENT_NAME_LEN_MAX);
    > +
    > + result = ima_store_template(&template, violation, inode);

    Is there any advantage to copying the data onto the
    stack here and passing that to ima_store_template(),
    instead of just kmallocing a ima_template_entry right
    here, just filling in the digest and file_name, and
    passing those to iam_store_template()?

    > + if (!result)
    > + iint->flags |= IMA_MEASURED;
    > +}
    > diff --git a/security/integrity/ima/ima_audit.c b/security/integrity/ima/ima_audit.c
    > new file mode 100644
    > index 0000000..8a0f1e2
    > --- /dev/null
    > +++ b/security/integrity/ima/ima_audit.c
    > @@ -0,0 +1,78 @@
    > +/*
    > + * Copyright (C) 2008 IBM Corporation
    > + * Author: Mimi Zohar <zohar@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: integrity_audit.c
    > + * Audit calls for the integrity subsystem
    > + */
    > +
    > +#include <linux/fs.h>
    > +#include <linux/audit.h>
    > +#include "ima.h"
    > +
    > +static int ima_audit;
    > +
    > +#ifdef CONFIG_IMA_AUDIT
    > +
    > +/* ima_audit_setup - enable informational auditing messages */
    > +static int __init ima_audit_setup(char *str)
    > +{
    > + unsigned long audit;
    > + int rc;
    > + char *op;
    > +
    > + rc = strict_strtoul(str, 0, &audit);
    > + if (rc || audit > 1)
    > + printk(KERN_INFO "ima: invalid ima_audit value\n");
    > + else
    > + ima_audit = audit;
    > + op = ima_audit ? "ima_audit_enabled" : "ima_audit_not_enabled";
    > + integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL, NULL, NULL, op, 0, 0);
    > + return 1;
    > +}
    > +__setup("ima_audit=", ima_audit_setup);
    > +#endif
    > +
    > +void integrity_audit_msg(int audit_msgno, struct inode *inode,
    > + const unsigned char *fname, const char *op,
    > + const char *cause, int result, int audit_info)
    > +{
    > + struct audit_buffer *ab;
    > +
    > + if (!ima_audit && audit_info == 1) /* Skip informational messages */
    > + return;
    > +
    > + ab = audit_log_start(current->audit_context, GFP_KERNEL, audit_msgno);
    > + audit_log_format(ab, "integrity: pid=%d uid=%u auid=%u",
    > + current->pid, current->cred->uid,
    > + audit_get_loginuid(current));
    > + audit_log_task_context(ab);
    > + switch (audit_msgno) {
    > + case AUDIT_INTEGRITY_DATA:
    > + case AUDIT_INTEGRITY_METADATA:
    > + case AUDIT_INTEGRITY_PCR:
    > + audit_log_format(ab, " op=%s cause=%s", op, cause);
    > + break;
    > + case AUDIT_INTEGRITY_HASH:
    > + audit_log_format(ab, " op=%s hash=%s", op, cause);
    > + break;
    > + case AUDIT_INTEGRITY_STATUS:
    > + default:
    > + audit_log_format(ab, " op=%s", op);
    > + }
    > + audit_log_format(ab, " comm=");
    > + audit_log_untrustedstring(ab, current->comm);
    > + if (fname) {
    > + audit_log_format(ab, " name=");
    > + audit_log_untrustedstring(ab, fname);
    > + }
    > + if (inode)
    > + audit_log_format(ab, " dev=%s ino=%lu",
    > + inode->i_sb->s_id, inode->i_ino);
    > + audit_log_format(ab, " res=%d", result);
    > + audit_log_end(ab);
    > +}
    > diff --git a/security/integrity/ima/ima_crypto.c b/security/integrity/ima/ima_crypto.c
    > new file mode 100644
    > index 0000000..c2a46e4
    > --- /dev/null
    > +++ b/security/integrity/ima/ima_crypto.c
    > @@ -0,0 +1,140 @@
    > +/*
    > + * Copyright (C) 2005,2006,2007,2008 IBM Corporation
    > + *
    > + * Authors:
    > + * Mimi Zohar <zohar@us.ibm.com>
    > + * Kylene Hall <kjhall@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_crypto.c
    > + * Calculates md5/sha1 file hash, template hash, boot-aggreate hash
    > + */
    > +
    > +#include <linux/kernel.h>
    > +#include <linux/file.h>
    > +#include <linux/crypto.h>
    > +#include <linux/scatterlist.h>
    > +#include <linux/err.h>
    > +#include "ima.h"
    > +
    > +static int init_desc(struct hash_desc *desc)
    > +{
    > + int rc;
    > +
    > + desc->tfm = crypto_alloc_hash(ima_hash, 0, CRYPTO_ALG_ASYNC);
    > + if (IS_ERR(desc->tfm)) {
    > + pr_info("failed to load %s transform: %ld\n",
    > + ima_hash, PTR_ERR(desc->tfm));
    > + rc = PTR_ERR(desc->tfm);
    > + return rc;
    > + }
    > + desc->flags = 0;
    > + rc = crypto_hash_init(desc);
    > + if (rc)
    > + crypto_free_hash(desc->tfm);
    > + return rc;
    > +}
    > +
    > +/*
    > + * Calculate the MD5/SHA1 file digest
    > + */
    > +int ima_calc_hash(struct file *file, char *digest)
    > +{
    > + struct hash_desc desc;
    > + struct scatterlist sg[1];
    > + loff_t i_size;
    > + char *rbuf;
    > + int rc, offset = 0;
    > +
    > + rc = init_desc(&desc);
    > + if (rc != 0)
    > + return rc;
    > +
    > + rbuf = kzalloc(PAGE_SIZE, GFP_KERNEL);
    > + if (!rbuf) {
    > + rc = -ENOMEM;
    > + goto out;
    > + }
    > + i_size = i_size_read(file->f_dentry->d_inode);
    > + while (offset < i_size) {
    > + int rbuf_len;
    > +
    > + rbuf_len = kernel_read(file, offset, rbuf, PAGE_SIZE);
    > + if (rbuf_len < 0) {
    > + rc = rbuf_len;
    > + break;
    > + }
    > + offset += rbuf_len;
    > + sg_set_buf(sg, rbuf, rbuf_len);
    > +
    > + rc = crypto_hash_update(&desc, sg, rbuf_len);
    > + if (rc)
    > + break;
    > + }
    > + kfree(rbuf);
    > + if (!rc)
    > + rc = crypto_hash_final(&desc, digest);
    > +out:
    > + crypto_free_hash(desc.tfm);
    > + return rc;
    > +}
    > +
    > +/*
    > + * Calculate the hash of a given template
    > + */
    > +int ima_calc_template_hash(int template_len, void *template, char *digest)
    > +{
    > + struct hash_desc desc;
    > + struct scatterlist sg[1];
    > + int rc;
    > +
    > + rc = init_desc(&desc);
    > + if (rc != 0)
    > + return rc;
    > +
    > + sg_set_buf(sg, template, template_len);
    > + rc = crypto_hash_update(&desc, sg, template_len);
    > + if (!rc)
    > + rc = crypto_hash_final(&desc, digest);
    > + crypto_free_hash(desc.tfm);
    > + return rc;
    > +}
    > +
    > +static void ima_pcrread(int idx, u8 *pcr)
    > +{
    > + if (!ima_used_chip)
    > + return;
    > +
    > + if (tpm_pcr_read(TPM_ANY_NUM, idx, pcr) != 0)
    > + pr_err("Error Communicating to TPM chip\n");
    > +}
    > +
    > +/*
    > + * Calculate the boot aggregate hash
    > + */
    > +int ima_calc_boot_aggregate(char *digest)
    > +{
    > + struct hash_desc desc;
    > + struct scatterlist sg;
    > + u8 pcr_i[IMA_DIGEST_SIZE];
    > + int rc, i;
    > +
    > + rc = init_desc(&desc);
    > + if (rc != 0)
    > + return rc;
    > +
    > + /* cumulative sha1 over tpm registers 0-7 */

    (Just out of curiosity) why? Are these the ones the BIOS and grub
    will use by convention?

    > + for (i = TPM_PCR0; i < TPM_PCR8; i++) {
    > + ima_pcrread(i, pcr_i);
    > + /* now accumulate with current aggregate */
    > + sg_init_one(&sg, pcr_i, IMA_DIGEST_SIZE);
    > + rc = crypto_hash_update(&desc, &sg, IMA_DIGEST_SIZE);
    > + }
    > + if (!rc)
    > + crypto_hash_final(&desc, digest);
    > + crypto_free_hash(desc.tfm);
    > + return rc;
    > +}
    > diff --git a/security/integrity/ima/ima_iint.c b/security/integrity/ima/ima_iint.c
    > new file mode 100644
    > index 0000000..750db3c
    > --- /dev/null
    > +++ b/security/integrity/ima/ima_iint.c
    > @@ -0,0 +1,185 @@
    > +/*
    > + * Copyright (C) 2008 IBM Corporation
    > + *
    > + * Authors:
    > + * Mimi Zohar <zohar@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_iint.c
    > + * - implements the IMA hooks: ima_inode_alloc, ima_inode_free
    > + * - cache integrity information associated with an inode
    > + * using a radix tree.
    > + */
    > +#include <linux/module.h>
    > +#include <linux/spinlock.h>
    > +#include <linux/radix-tree.h>
    > +#include "ima.h"
    > +
    > +#define ima_iint_delete ima_inode_free
    > +
    > +RADIX_TREE(ima_iint_store, GFP_ATOMIC);
    > +DEFINE_SPINLOCK(ima_iint_lock);
    > +
    > +static struct kmem_cache *iint_cache __read_mostly;
    > +
    > +/* ima_iint_find_get - return the iint associated with an inode
    > + *
    > + * ima_iint_find_get gets a reference to the iint. Caller must
    > + * remember to put the iint reference.
    > + */
    > +struct ima_iint_cache *ima_iint_find_get(struct inode *inode)
    > +{
    > + struct ima_iint_cache *iint;
    > +
    > + rcu_read_lock();
    > + iint = radix_tree_lookup(&ima_iint_store, (unsigned long)inode);
    > + if (!iint)
    > + goto out;
    > + kref_get(&iint->refcount);
    > +out:
    > + rcu_read_unlock();
    > + return iint;
    > +}
    > +
    > +/* Allocate memory for the iint associated with the inode
    > + * from the iint_cache slab, initialize the iint, and
    > + * insert it into the radix tree.
    > + *
    > + * On success return a pointer to the iint; on failure return NULL.
    > + */
    > +struct ima_iint_cache *ima_iint_insert(struct inode *inode)
    > +{
    > + struct ima_iint_cache *iint = NULL;
    > + int rc = 0;
    > +
    > + if (!ima_initialized)
    > + return iint;
    > + iint = kmem_cache_alloc(iint_cache, GFP_KERNEL);
    > + if (!iint)
    > + return iint;
    > +
    > + rc = radix_tree_preload(GFP_KERNEL);
    > + if (rc < 0)
    > + goto out;
    > +
    > + spin_lock(&ima_iint_lock);
    > + rc = radix_tree_insert(&ima_iint_store, (unsigned long)inode, iint);
    > + spin_unlock(&ima_iint_lock);
    > +out:
    > + if (rc < 0) {
    > + kmem_cache_free(iint_cache, iint);
    > + if (rc == -EEXIST) {
    > + iint = radix_tree_lookup(&ima_iint_store,
    > + (unsigned long)inode);
    > + } else
    > + iint = NULL;
    > + }
    > + radix_tree_preload_end();
    > + return iint;
    > +}
    > +
    > +/**
    > + * ima_inode_alloc - allocate an iint associated with an inode
    > + * @inode: pointer to the inode
    > + *
    > + * Return 0 on success, 1 on failure.
    > + */
    > +int ima_inode_alloc(struct inode *inode)
    > +{
    > + struct ima_iint_cache *iint;
    > +
    > + if (!ima_initialized)
    > + return 0;
    > +
    > + iint = ima_iint_insert(inode);
    > + if (!iint)
    > + return 1;
    > + return 0;
    > +}
    > +
    > +/* ima_iint_find_insert_get - get the iint associated with an inode
    > + *
    > + * Most insertions are done at inode_alloc, except those allocated
    > + * before late_initcall. When the iint does not exist, allocate it,
    > + * initialize and insert it, and increment the iint refcount.
    > + *
    > + * (Can't initialize at security_initcall before any inodes are
    > + * allocated, got to wait at least until proc_init.)
    > + *
    > + * Return the iint.
    > + */
    > +struct ima_iint_cache *ima_iint_find_insert_get(struct inode *inode)
    > +{
    > + struct ima_iint_cache *iint = NULL;
    > +
    > + iint = ima_iint_find_get(inode);
    > + if (iint)
    > + return iint;
    > +
    > + iint = ima_iint_insert(inode);
    > + if (iint)
    > + kref_get(&iint->refcount);
    > +
    > + return iint;
    > +}
    > +
    > +/* iint_free - called when the iint refcount goes to zero */
    > +void iint_free(struct kref *kref)
    > +{
    > + struct ima_iint_cache *iint = container_of(kref, struct ima_iint_cache,
    > + refcount);
    > + iint->version = 0;
    > + iint->flags = 0UL;
    > + kref_set(&iint->refcount, 1);
    > + kmem_cache_free(iint_cache, iint);
    > +}
    > +
    > +void iint_rcu_free(struct rcu_head *rcu_head)
    > +{
    > + struct ima_iint_cache *iint = container_of(rcu_head,
    > + struct ima_iint_cache, rcu);
    > + kref_put(&iint->refcount, iint_free);
    > +}
    > +
    > +/**
    > + * ima_iint_delete - called on integrity_inode_free
    > + * @inode: pointer to the inode
    > + *
    > + * Free the integrity information(iint) associated with an inode.
    > + */
    > +void ima_iint_delete(struct inode *inode)
    > +{
    > + struct ima_iint_cache *iint;
    > +
    > + if (!ima_initialized)
    > + return;
    > + spin_lock(&ima_iint_lock);
    > + iint = radix_tree_delete(&ima_iint_store, (unsigned long)inode);
    > + spin_unlock(&ima_iint_lock);
    > + if (iint)
    > + call_rcu(&iint->rcu, iint_rcu_free);
    > +}
    > +
    > +static void init_once(void *foo)
    > +{
    > + struct ima_iint_cache *iint = foo;
    > +
    > + memset(iint, 0, sizeof *iint);
    > + iint->version = 0;
    > + iint->flags = 0UL;
    > + mutex_init(&iint->mutex);
    > + iint->readcount = 0;
    > + iint->writecount = 0;
    > + kref_set(&iint->refcount, 1);
    > +}
    > +
    > +void ima_iintcache_init(void)
    > +{
    > + iint_cache =
    > + kmem_cache_create("iint_cache", sizeof(struct ima_iint_cache), 0,
    > + SLAB_PANIC, init_once);
    > +}
    > diff --git a/security/integrity/ima/ima_init.c b/security/integrity/ima/ima_init.c
    > new file mode 100644
    > index 0000000..e681a40
    > --- /dev/null
    > +++ b/security/integrity/ima/ima_init.c
    > @@ -0,0 +1,73 @@
    > +/*
    > + * Copyright (C) 2005,2006,2007,2008 IBM Corporation
    > + *
    > + * Authors:
    > + * Reiner Sailer <sailer@watson.ibm.com>
    > + * Leendert van Doorn <leendert@watson.ibm.com>
    > + * Mimi Zohar <zohar@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_init.c
    > + * initialization and cleanup functions
    > + */
    > +#include <linux/module.h>
    > +#include <linux/scatterlist.h>
    > +#include <linux/err.h>
    > +#include "ima.h"
    > +
    > +/* name for boot aggregate entry */
    > +static char *boot_aggregate_name = "boot_aggregate";
    > +int ima_used_chip;
    > +
    > +/* Add the boot aggregate to the IMA measurement list and extend
    > + * the PCR register.
    > + *
    > + * Calculate the boot aggregate, a SHA1 over tpm registers 0-7,
    > + * assuming a TPM chip exists, and zeroes if the TPM chip does not
    > + * exist. Add the boot aggregate measurement to the measurement
    > + * list and extend the PCR register.
    > + *
    > + * If a tpm chip does not exist, indicate the core root of trust is
    > + * not hardware based by invalidating the aggregate PCR value.
    > + * (The aggregate PCR value is invalidated by adding one value to
    > + * the measurement list and extending the aggregate PCR value with
    > + * a different value.) Violations add a zero entry to the measurement
    > + * list and extend the aggregate PCR value with ff...ff's.
    > + */
    > +static void ima_add_boot_aggregate(void)
    > +{
    > + struct ima_template_data template;
    > + int violation = 1;
    > + int result;
    > +
    > + memset(&template, 0, sizeof(template));
    > + strncpy(template.file_name, boot_aggregate_name,
    > + IMA_EVENT_NAME_LEN_MAX);
    > +
    > + if (ima_used_chip) {
    > + violation = 0;
    > + ima_calc_boot_aggregate(template.digest);

    You're ignoring the return value of ima_calc_boot_aggregate...

    > + }
    > + result = ima_store_template(&template, violation, NULL);

    ...and effectively ignoring result?

    I realize it shouldn't ever matter...

    > +}
    > +
    > +int ima_init(void)
    > +{
    > + int rc;
    > +
    > + ima_used_chip = 0;
    > + rc = tpm_pcr_read(TPM_ANY_NUM, 0, NULL);
    > + if (rc == 0)
    > + ima_used_chip = 1;
    > +
    > + if (!ima_used_chip)
    > + pr_info("No TPM chip found, activating TPM-bypass!\n");
    > +
    > + ima_add_boot_aggregate(); /* boot aggregate must be first entry */
    > + ima_init_policy();
    > + return 0;
    > +}
    > diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
    > new file mode 100644
    > index 0000000..53cee4c
    > --- /dev/null
    > +++ b/security/integrity/ima/ima_main.c
    > @@ -0,0 +1,280 @@
    > +/*
    > + * Copyright (C) 2005,2006,2007,2008 IBM Corporation
    > + *
    > + * Authors:
    > + * Reiner Sailer <sailer@watson.ibm.com>
    > + * Serge Hallyn <serue@us.ibm.com>
    > + * Kylene Hall <kylene@us.ibm.com>
    > + * Mimi Zohar <zohar@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 the IMA hooks: ima_bprm_check, ima_file_mmap,
    > + * and ima_path_check.
    > + */
    > +#include <linux/module.h>
    > +#include <linux/file.h>
    > +#include <linux/binfmts.h>
    > +#include <linux/mount.h>
    > +#include <linux/mman.h>
    > +
    > +#include "ima.h"
    > +
    > +int ima_initialized;
    > +
    > +char *ima_hash = "sha1";
    > +static int __init hash_setup(char *str)
    > +{
    > + const char *op = "hash_setup";
    > + const char *hash = "sha1";
    > + int result = 0;
    > + int audit_info = 0;
    > +
    > + if (strncmp(str, "md5", 3) == 0) {
    > + hash = "md5";
    > + ima_hash = str;
    > + } else if (strncmp(str, "sha1", 4) != 0) {
    > + hash = "invalid_hash_type";
    > + result = 1;
    > + }
    > + integrity_audit_msg(AUDIT_INTEGRITY_HASH, NULL, NULL, op, hash,
    > + result, audit_info);
    > + return 1;
    > +}
    > +__setup("ima_hash=", hash_setup);
    > +
    > +/**
    > + * ima_file_free - called on __fput()
    > + * @file: pointer to file structure being freed
    > + *
    > + * Flag files that changed, based on i_version;
    > + * and decrement the iint readcount/writecount.
    > + */
    > +void ima_file_free(struct file *file)
    > +{
    > + struct inode *inode = file->f_dentry->d_inode;
    > + struct ima_iint_cache *iint;
    > +
    > + if (!ima_initialized || !S_ISREG(inode->i_mode))
    > + return;
    > + iint = ima_iint_find_get(inode);
    > + if (!iint)
    > + return;
    > +
    > + mutex_lock(&iint->mutex);
    > + if ((file->f_mode & (FMODE_READ | FMODE_WRITE)) == FMODE_READ)
    > + iint->readcount--;
    > +
    > + if (file->f_mode & FMODE_WRITE) {
    > + iint->writecount--;
    > + if (iint->writecount == 0) {
    > + if (iint->version != inode->i_version)
    > + iint->flags &= ~IMA_MEASURED;
    > + }
    > + }
    > + mutex_unlock(&iint->mutex);
    > + kref_put(&iint->refcount, iint_free);
    > +}
    > +
    > +/* ima_read_write_check - reflect possible reading/writing errors in the PCR.
    > + *
    > + * When opening a file for read, if the file is already open for write,
    > + * the file could change, resulting in a file measurement error.
    > + *
    > + * Opening a file for write, if the file is already open for read, results
    > + * in a time of measure, time of use (ToMToU) error.
    > + *
    > + * In either case invalidate the PCR.
    > + */
    > +enum iint_pcr_error { TOMTOU, OPEN_WRITERS };
    > +static void ima_read_write_check(enum iint_pcr_error error,
    > + struct ima_iint_cache *iint,
    > + struct inode *inode,
    > + const unsigned char *filename)
    > +{
    > + switch (error) {
    > + case TOMTOU:
    > + if (iint->readcount > 0)
    > + ima_add_violation(inode, filename, "invalid_pcr",
    > + "ToMToU");
    > + break;
    > + case OPEN_WRITERS:
    > + if (iint->writecount > 0)
    > + ima_add_violation(inode, filename, "invalid_pcr",
    > + "open_writers");
    > + break;
    > + }
    > +}
    > +
    > +static int get_path_measurement(struct ima_iint_cache *iint, struct file *file,
    > + const unsigned char *filename)
    > +{
    > + int rc = 0;
    > +
    > + if (IS_ERR(file)) {
    > + pr_info("%s dentry_open failed\n", filename);
    > + return rc;
    > + }
    > + iint->readcount++;
    > +
    > + rc = ima_collect_measurement(iint, file);
    > + if (!rc)
    > + ima_store_measurement(iint, file, filename);
    > + return rc;
    > +}
    > +
    > +/**
    > + * ima_path_check - based on policy, collect/store measurement.
    > + * @path: contains a pointer to the path to be measured
    > + * @mask: contains MAY_READ, MAY_WRITE or MAY_EXECUTE
    > + *
    > + * Measure the file being open for readonly, based on the
    > + * ima_must_measure() policy decision.
    > + *
    > + * Keep read/write counters for all files, but only
    > + * invalidate the PCR for measured files:
    > + * - Opening a file for write when already open for read,
    > + * results in a time of measure, time of use (ToMToU) error.
    > + * - Opening a file for read when already open for write,
    > + * could result in a file measurement error.
    > + *
    > + * Return 0 on success, an error code on failure.
    > + * (Based on the results of appraise_measurement().)
    > + */
    > +int ima_path_check(struct path *path, int mask)
    > +{
    > + struct inode *inode = path->dentry->d_inode;
    > + struct ima_iint_cache *iint;
    > + struct file *file = NULL;
    > + int rc;
    > +
    > + if (!ima_initialized || !S_ISREG(inode->i_mode))
    > + return 0;
    > + iint = ima_iint_find_insert_get(inode);
    > + if (!iint)
    > + return 0;
    > +
    > + mutex_lock(&iint->mutex);
    > + if ((mask & MAY_WRITE) || (mask == 0))
    > + iint->writecount++;
    > + else if (mask & (MAY_READ | MAY_EXEC))
    > + iint->readcount++;
    > +
    > + rc = ima_must_measure(iint, inode, MAY_READ, PATH_CHECK);

    why MAY_READ, if mask could have MAY_WRITE?

    > + if (rc < 0)
    > + goto out;
    > +
    > + if ((mask & MAY_WRITE) || (mask == 0))
    > + ima_read_write_check(TOMTOU, iint, inode,
    > + path->dentry->d_name.name);
    > +
    > + if ((mask & (MAY_WRITE | MAY_READ | MAY_EXEC)) != MAY_READ)
    > + goto out;
    > +
    > + ima_read_write_check(OPEN_WRITERS, iint, inode,
    > + path->dentry->d_name.name);
    > + if (!(iint->flags & IMA_MEASURED)) {
    > + struct dentry *dentry = dget(path->dentry);
    > + struct vfsmount *mnt = mntget(path->mnt);
    > +
    > + file = dentry_open(dentry, mnt, O_RDONLY, current->cred);
    > + rc = get_path_measurement(iint, file, dentry->d_name.name);
    > + }
    > +out:
    > + mutex_unlock(&iint->mutex);
    > + if (file)
    > + fput(file);
    > + kref_put(&iint->refcount, iint_free);
    > + return 0;
    > +}
    > +
    > +static int process_measurement(struct file *file, const unsigned char *filename,
    > + int mask, int function)
    > +{
    > + struct inode *inode = file->f_dentry->d_inode;
    > + struct ima_iint_cache *iint;
    > + int rc;
    > +
    > + if (!ima_initialized || !S_ISREG(inode->i_mode))
    > + return 0;
    > + iint = ima_iint_find_insert_get(inode);
    > + if (!iint)
    > + return -ENOMEM;
    > +
    > + mutex_lock(&iint->mutex);
    > + rc = ima_must_measure(iint, inode, mask, function);
    > + if (rc != 0)
    > + goto out;
    > +
    > + rc = ima_collect_measurement(iint, file);
    > + if (!rc)
    > + ima_store_measurement(iint, file, filename);
    > +out:
    > + mutex_unlock(&iint->mutex);
    > + kref_put(&iint->refcount, iint_free);
    > + return rc;
    > +}
    > +
    > +/**
    > + * ima_file_mmap - based on policy, collect/store measurement.
    > + * @file: pointer to the file to be measured (May be NULL)
    > + * @prot: contains the protection that will be applied by the kernel.
    > + *
    > + * Measure files being mmapped executable based on the ima_must_measure()
    > + * policy decision.
    > + *
    > + * Return 0 on success, an error code on failure.
    > + * (Based on the results of appraise_measurement().)
    > + */
    > +int ima_file_mmap(struct file *file, unsigned long prot)
    > +{
    > + int rc;
    > +
    > + if (!file)
    > + return 0;
    > + if (prot & PROT_EXEC)
    > + rc = process_measurement(file, file->f_dentry->d_name.name,
    > + MAY_EXEC, FILE_MMAP);
    > + return 0;
    > +}
    > +
    > +/**
    > + * ima_bprm_check - based on policy, collect/store measurement.
    > + * @bprm: contains the linux_binprm structure
    > + *
    > + * The OS protects against an executable file, already open for write,
    > + * from being executed in deny_write_access() and an executable file,
    > + * already open for execute, from being modified in get_write_access().
    > + * So we can be certain that what we verify and measure here is actually
    > + * what is being executed.
    > + *
    > + * Return 0 on success, an error code on failure.
    > + * (Based on the results of appraise_measurement().)
    > + */
    > +int ima_bprm_check(struct linux_binprm *bprm)
    > +{
    > + int rc;
    > +
    > + rc = process_measurement(bprm->file, bprm->filename,
    > + MAY_EXEC, BPRM_CHECK);
    > + return 0;

    ?

    > +}
    > +
    > +static int __init init_ima(void)
    > +{
    > + int error;
    > +
    > + ima_iintcache_init();
    > + error = ima_init();
    > + ima_initialized = 1;
    > + return error;
    > +}
    > +
    > +late_initcall(init_ima); /* Start IMA after the TPM is available */
    > +
    > +MODULE_DESCRIPTION("Integrity Measurement Architecture");
    > +MODULE_LICENSE("GPL");
    > diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
    > new file mode 100644
    > index 0000000..7c3d1ff
    > --- /dev/null
    > +++ b/security/integrity/ima/ima_policy.c
    > @@ -0,0 +1,126 @@
    > +/*
    > + * Copyright (C) 2008 IBM Corporation
    > + * Author: Mimi Zohar <zohar@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.
    > + *
    > + * ima_policy.c
    > + * - initialize default measure policy rules
    > + *
    > + */
    > +#include <linux/module.h>
    > +#include <linux/list.h>
    > +#include <linux/audit.h>
    > +#include <linux/security.h>
    > +#include <linux/magic.h>
    > +
    > +#include "ima.h"
    > +
    > +/* flags definitions */
    > +#define IMA_FUNC 0x0001
    > +#define IMA_MASK 0x0002
    > +#define IMA_FSMAGIC 0x0004
    > +#define IMA_UID 0x0008
    > +
    > +enum ima_action { DONT_MEASURE, MEASURE };
    > +
    > +struct ima_measure_rule_entry {
    > + struct list_head list;
    > + enum ima_action action;
    > + unsigned int flags;
    > + enum ima_hooks func;
    > + int mask;
    > + unsigned long fsmagic;
    > + uid_t uid;
    > +};
    > +
    > +static struct ima_measure_rule_entry default_rules[] = {
    > + {.action = DONT_MEASURE,.fsmagic = PROC_SUPER_MAGIC,
    > + .flags = IMA_FSMAGIC},
    > + {.action = DONT_MEASURE,.fsmagic = SYSFS_MAGIC,.flags = IMA_FSMAGIC},
    > + {.action = DONT_MEASURE,.fsmagic = DEBUGFS_MAGIC,.flags = IMA_FSMAGIC},
    > + {.action = DONT_MEASURE,.fsmagic = TMPFS_MAGIC,.flags = IMA_FSMAGIC},
    > + {.action = DONT_MEASURE,.fsmagic = SECURITYFS_MAGIC,
    > + .flags = IMA_FSMAGIC},
    > + {.action = DONT_MEASURE,.fsmagic = 0xF97CFF8C,.flags = IMA_FSMAGIC},
    > + {.action = MEASURE,.func = FILE_MMAP,.mask = MAY_EXEC,
    > + .flags = IMA_FUNC | IMA_MASK},
    > + {.action = MEASURE,.func = BPRM_CHECK,.mask = MAY_EXEC,
    > + .flags = IMA_FUNC | IMA_MASK},
    > + {.action = MEASURE,.func = PATH_CHECK,.mask = MAY_READ,.uid = 0,
    > + .flags = IMA_FUNC | IMA_MASK | IMA_UID}
    > +};
    > +
    > +static LIST_HEAD(measure_default_rules);
    > +static struct list_head *ima_measure;
    > +
    > +/**
    > + * ima_match_rules - determine whether an inode matches the measure rule.
    > + * @rule: a pointer to a rule
    > + * @inode: a pointer to an inode
    > + * @func: LIM hook identifier
    > + * @mask: requested action (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC)
    > + *
    > + * Returns true on rule match, false on failure.
    > + */
    > +static bool ima_match_rules(struct ima_measure_rule_entry *rule,
    > + struct inode *inode, enum ima_hooks func, int mask)
    > +{
    > + struct task_struct *tsk = current;
    > +
    > + if ((rule->flags & IMA_FUNC) && rule->func != func)
    > + return false;
    > + if ((rule->flags & IMA_MASK) && rule->mask != mask)
    > + return false;
    > + if ((rule->flags & IMA_FSMAGIC)
    > + && rule->fsmagic != inode->i_sb->s_magic)
    > + return false;
    > + if ((rule->flags & IMA_UID) && rule->uid != tsk->cred->uid)
    > + return false;
    > + return true;
    > +}
    > +
    > +/**
    > + * ima_match_policy - decision based on LSM and other conditions
    > + * @inode: pointer to an inode for which the policy decision is being made
    > + * @func: IMA hook identifier
    > + * @mask: requested action (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC)
    > + *
    > + * Measure decision based on func/mask/fsmagic and LSM(subj/obj/type)
    > + * conditions.
    > + *
    > + * (There is no need for locking when walking the policy list,
    > + * as elements in the list are never deleted, nor does the list
    > + * change.)
    > + */
    > +int ima_match_policy(struct inode *inode, enum ima_hooks func, int mask)
    > +{
    > + struct ima_measure_rule_entry *entry;
    > +
    > + list_for_each_entry(entry, ima_measure, list) {

    The list never changes, but once per boot the value of ima_measure
    itself can change (at least after a later patch). Does that matter?
    Could you end up with a corrupt value here?

    > + bool rc;
    > +
    > + rc = ima_match_rules(entry, inode, func, mask);
    > + if (rc)
    > + return entry->action;
    > + }
    > + return 0;
    > +}
    > +
    > +/**
    > + * ima_init_policy - initialize the default measure rules.
    > + *
    > + * (Could use the default_rules directly, but in policy patch
    > + * ima_measure points to either the measure_default_rules or the
    > + * the new measure_policy_rules.)
    > + */
    > +void ima_init_policy(void)
    > +{
    > + int i;
    > +
    > + for (i = 0; i < ARRAY_SIZE(default_rules); i++)
    > + list_add_tail(&default_rules[i].list, &measure_default_rules);
    > + ima_measure = &measure_default_rules;
    > +}
    > diff --git a/security/integrity/ima/ima_queue.c b/security/integrity/ima/ima_queue.c
    > new file mode 100644
    > index 0000000..7cb518f
    > --- /dev/null
    > +++ b/security/integrity/ima/ima_queue.c
    > @@ -0,0 +1,138 @@
    > +/*
    > + * Copyright (C) 2005,2006,2007,2008 IBM Corporation
    > + *
    > + * Authors:
    > + * Serge Hallyn <serue@us.ibm.com>
    > + * Reiner Sailer <sailer@watson.ibm.com>
    > + * Mimi Zohar <zohar@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_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/module.h>
    > +#include <linux/rculist.h>
    > +#include "ima.h"
    > +
    > +LIST_HEAD(ima_measurements); /* list of all measurements */
    > +
    > +/* key: inode (before secure-hashing a file) */
    > +struct ima_h_table ima_htable = {
    > + .len = ATOMIC_LONG_INIT(0),
    > + .violations = ATOMIC_LONG_INIT(0),
    > + .queue[0 ... IMA_MEASURE_HTABLE_SIZE - 1] = HLIST_HEAD_INIT
    > +};
    > +
    > +/* 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)
    > +{
    > + 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;
    > +}
    > +
    > +/* ima_add_template_entry helper function:
    > + * - Add template entry to measurement list and hash table.
    > + *
    > + * (Called with ima_extend_list_mutex held.)
    > + */
    > +static int ima_add_digest_entry(struct ima_template_entry *entry)
    > +{
    > + struct ima_queue_entry *qe;
    > + unsigned int key;
    > +
    > + qe = kmalloc(sizeof(*qe), GFP_KERNEL);
    > + if (qe == NULL) {
    > + pr_err("OUT OF MEMORY ERROR creating queue entry.\n");
    > + return -ENOMEM;
    > + }
    > + qe->entry = entry;
    > +
    > + INIT_LIST_HEAD(&qe->later);
    > + list_add_tail_rcu(&qe->later, &ima_measurements);
    > +
    > + atomic_long_inc(&ima_htable.len);
    > + key = ima_hash_key(entry->digest);
    > + hlist_add_head_rcu(&qe->hnext, &ima_htable.queue[key]);
    > + return 0;
    > +}
    > +
    > +static int ima_pcr_extend(const u8 *hash)
    > +{
    > + int result = 0;
    > +
    > + if (!ima_used_chip)
    > + return result;
    > +
    > + result = tpm_pcr_extend(TPM_ANY_NUM, CONFIG_IMA_MEASURE_PCR_IDX, hash);
    > + if (result != 0)
    > + pr_err("Error Communicating to TPM chip\n");
    > + return result;
    > +}
    > +
    > +/* Add template entry to the measurement list and hash table,
    > + * and extend the pcr.
    > + */
    > +int ima_add_template_entry(struct ima_template_entry *entry, int violation,
    > + const char *op, struct inode *inode)
    > +{
    > + u8 digest[IMA_DIGEST_SIZE];
    > + const char *audit_cause = "hash_added";
    > + int audit_info = 1;
    > + int result = 0;
    > +
    > + mutex_lock(&ima_extend_list_mutex);
    > + if (!violation) {
    > + memcpy(digest, entry->digest, sizeof digest);
    > + if (ima_lookup_digest_entry(digest)) {
    > + audit_cause = "hash_exists";
    > + goto out;

    Ok so not that I'm saying this would be easy, but an attacker
    compromising say ftpd doesn't need to come up with a compromised
    ftpd where sha1sum(evilftpd)==sha1sum(origftpd) - he just needs to
    come up with one wher sha1sum(evilftpd)==sha1sum(X) where X is
    any pristine program already loaded. Right?

    Is checking that strcmp(entry->file_name, newfilename)==0 warranted
    here, or am I being silly?

    > + }
    > + }
    > +
    > + result = ima_add_digest_entry(entry);
    > + if (result < 0) {
    > + audit_cause = "ENOMEM";
    > + audit_info = 0;
    > + goto out;
    > + }
    > +
    > + if (violation) /* invalidate pcr */
    > + memset(digest, 0xff, sizeof digest);
    > +
    > + result = ima_pcr_extend(digest);
    > + if (result != 0) {
    > + audit_cause = "TPM error";
    > + audit_info = 0;
    > + }
    > +out:
    > + mutex_unlock(&ima_extend_list_mutex);
    > + integrity_audit_msg(AUDIT_INTEGRITY_PCR, inode, entry->template_name,
    > + op, audit_cause, result, audit_info);
    > + return result;
    > +}
    > --
    > 1.5.6.6
    >
    > --
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