[mirror_ubuntu-bionic-kernel.git] / security / integrity / ima / ima_main.c

/*
 * 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_file_check.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/module.h>
#include <linux/file.h>
#include <linux/binfmts.h>
#include <linux/mount.h>
#include <linux/mman.h>
#include <linux/slab.h>
#include <linux/xattr.h>
#include <linux/ima.h>

#include "ima.h"

int ima_initialized;

#ifdef CONFIG_IMA_APPRAISE
int ima_appraise = IMA_APPRAISE_ENFORCE;
#else
int ima_appraise;
#endif

int ima_hash_algo = HASH_ALGO_SHA1;
static int hash_setup_done;

static int __init hash_setup(char *str)
{
	struct ima_template_desc *template_desc = ima_template_desc_current();
	int i;

	if (hash_setup_done)
		return 1;

	if (strcmp(template_desc->name, IMA_TEMPLATE_IMA_NAME) == 0) {
		if (strncmp(str, "sha1", 4) == 0)
			ima_hash_algo = HASH_ALGO_SHA1;
		else if (strncmp(str, "md5", 3) == 0)
			ima_hash_algo = HASH_ALGO_MD5;
		else
			return 1;
		goto out;
	}

	for (i = 0; i < HASH_ALGO__LAST; i++) {
		if (strcmp(str, hash_algo_name[i]) == 0) {
			ima_hash_algo = i;
			break;
		}
	}
	if (i == HASH_ALGO__LAST)
		return 1;
out:
	hash_setup_done = 1;
	return 1;
}
__setup("ima_hash=", hash_setup);

/*
 * ima_rdwr_violation_check
 *
 * 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.
 *
 */
static void ima_rdwr_violation_check(struct file *file,
				     struct integrity_iint_cache *iint,
				     int must_measure,
				     char **pathbuf,
				     const char **pathname)
{
	struct inode *inode = file_inode(file);
	char filename[NAME_MAX];
	fmode_t mode = file->f_mode;
	bool send_tomtou = false, send_writers = false;

	if (mode & FMODE_WRITE) {
		if (atomic_read(&inode->i_readcount) && IS_IMA(inode)) {
			if (!iint)
				iint = integrity_iint_find(inode);
			/* IMA_MEASURE is set from reader side */
			if (iint && test_bit(IMA_MUST_MEASURE,
						&iint->atomic_flags))
				send_tomtou = true;
		}
	} else {
		if (must_measure)
			set_bit(IMA_MUST_MEASURE, &iint->atomic_flags);
		if ((atomic_read(&inode->i_writecount) > 0) && must_measure)
			send_writers = true;
	}

	if (!send_tomtou && !send_writers)
		return;

	*pathname = ima_d_path(&file->f_path, pathbuf, filename);

	if (send_tomtou)
		ima_add_violation(file, *pathname, iint,
				  "invalid_pcr", "ToMToU");
	if (send_writers)
		ima_add_violation(file, *pathname, iint,
				  "invalid_pcr", "open_writers");
}

static void ima_check_last_writer(struct integrity_iint_cache *iint,
				  struct inode *inode, struct file *file)
{
	fmode_t mode = file->f_mode;
	bool update;

	if (!(mode & FMODE_WRITE))
		return;

	mutex_lock(&iint->mutex);
	if (atomic_read(&inode->i_writecount) == 1) {
		update = test_and_clear_bit(IMA_UPDATE_XATTR,
					    &iint->atomic_flags);
		if ((iint->version != inode->i_version) ||
		    (iint->flags & IMA_NEW_FILE)) {
			iint->flags &= ~(IMA_DONE_MASK | IMA_NEW_FILE);
			iint->measured_pcrs = 0;
			if (update)
				ima_update_xattr(iint, file);
		}
	}
	mutex_unlock(&iint->mutex);
}

/**
 * ima_file_free - called on __fput()
 * @file: pointer to file structure being freed
 *
 * Flag files that changed, based on i_version
 */
void ima_file_free(struct file *file)
{
	struct inode *inode = file_inode(file);
	struct integrity_iint_cache *iint;

	if (!ima_policy_flag || !S_ISREG(inode->i_mode))
		return;

	iint = integrity_iint_find(inode);
	if (!iint)
		return;

	ima_check_last_writer(iint, inode, file);
}

static int process_measurement(struct file *file, char *buf, loff_t size,
			       int mask, enum ima_hooks func, int opened)
{
	struct inode *inode = file_inode(file);
	struct integrity_iint_cache *iint = NULL;
	struct ima_template_desc *template_desc;
	char *pathbuf = NULL;
	char filename[NAME_MAX];
	const char *pathname = NULL;
	int rc = 0, action, must_appraise = 0;
	int pcr = CONFIG_IMA_MEASURE_PCR_IDX;
	struct evm_ima_xattr_data *xattr_value = NULL;
	int xattr_len = 0;
	bool violation_check;
	enum hash_algo hash_algo;

	if (!ima_policy_flag || !S_ISREG(inode->i_mode))
		return 0;

	/* Return an IMA_MEASURE, IMA_APPRAISE, IMA_AUDIT action
	 * bitmask based on the appraise/audit/measurement policy.
	 * Included is the appraise submask.
	 */
	action = ima_get_action(inode, mask, func, &pcr);
	violation_check = ((func == FILE_CHECK || func == MMAP_CHECK) &&
			   (ima_policy_flag & IMA_MEASURE));
	if (!action && !violation_check)
		return 0;

	must_appraise = action & IMA_APPRAISE;

	/*  Is the appraise rule hook specific?  */
	if (action & IMA_FILE_APPRAISE)
		func = FILE_CHECK;

	inode_lock(inode);

	if (action) {
		iint = integrity_inode_get(inode);
		if (!iint)
			rc = -ENOMEM;
	}

	if (!rc && violation_check)
		ima_rdwr_violation_check(file, iint, action & IMA_MEASURE,
					 &pathbuf, &pathname);

	inode_unlock(inode);

	if (rc)
		goto out;
	if (!action)
		goto out;

	mutex_lock(&iint->mutex);

	if (test_and_clear_bit(IMA_CHANGE_ATTR, &iint->atomic_flags))
		/* reset appraisal flags if ima_inode_post_setattr was called */
		iint->flags &= ~(IMA_APPRAISE | IMA_APPRAISED |
				 IMA_APPRAISE_SUBMASK | IMA_APPRAISED_SUBMASK |
				 IMA_ACTION_FLAGS);

	if (test_and_clear_bit(IMA_CHANGE_XATTR, &iint->atomic_flags))
		/* reset all flags if ima_inode_setxattr was called */
		iint->flags &= ~IMA_DONE_MASK;

	/* Determine if already appraised/measured based on bitmask
	 * (IMA_MEASURE, IMA_MEASURED, IMA_XXXX_APPRAISE, IMA_XXXX_APPRAISED,
	 *  IMA_AUDIT, IMA_AUDITED)
	 */
	iint->flags |= action;
	action &= IMA_DO_MASK;
	action &= ~((iint->flags & (IMA_DONE_MASK ^ IMA_MEASURED)) >> 1);

	/* If target pcr is already measured, unset IMA_MEASURE action */
	if ((action & IMA_MEASURE) && (iint->measured_pcrs & (0x1 << pcr)))
		action ^= IMA_MEASURE;

	/* Nothing to do, just return existing appraised status */
	if (!action) {
		if (must_appraise)
			rc = ima_get_cache_status(iint, func);
		goto out_locked;
	}

	template_desc = ima_template_desc_current();
	if ((action & IMA_APPRAISE_SUBMASK) ||
		    strcmp(template_desc->name, IMA_TEMPLATE_IMA_NAME) != 0)
		/* read 'security.ima' */
		xattr_len = ima_read_xattr(file_dentry(file), &xattr_value);

	hash_algo = ima_get_hash_algo(xattr_value, xattr_len);

	rc = ima_collect_measurement(iint, file, buf, size, hash_algo);
	if (rc != 0 && rc != -EBADF && rc != -EINVAL)
		goto out_locked;

	if (!pathbuf)	/* ima_rdwr_violation possibly pre-fetched */
		pathname = ima_d_path(&file->f_path, &pathbuf, filename);

	if (action & IMA_MEASURE)
		ima_store_measurement(iint, file, pathname,
				      xattr_value, xattr_len, pcr);
	if (rc == 0 && (action & IMA_APPRAISE_SUBMASK)) {
		inode_lock(inode);
		rc = ima_appraise_measurement(func, iint, file, pathname,
					      xattr_value, xattr_len, opened);
		inode_unlock(inode);
	}
	if (action & IMA_AUDIT)
		ima_audit_measurement(iint, pathname);

	if ((file->f_flags & O_DIRECT) && (iint->flags & IMA_PERMIT_DIRECTIO))
		rc = 0;
out_locked:
	if ((mask & MAY_WRITE) && test_bit(IMA_DIGSIG, &iint->atomic_flags) &&
	     !(iint->flags & IMA_NEW_FILE))
		rc = -EACCES;
	mutex_unlock(&iint->mutex);
	kfree(xattr_value);
out:
	if (pathbuf)
		__putname(pathbuf);
	if (must_appraise) {
		if (rc && (ima_appraise & IMA_APPRAISE_ENFORCE))
			return -EACCES;
		if (file->f_mode & FMODE_WRITE)
			set_bit(IMA_UPDATE_XATTR, &iint->atomic_flags);
	}
	return 0;
}

/**
 * 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.
 *
 * On success return 0.  On integrity appraisal error, assuming the file
 * is in policy and IMA-appraisal is in enforcing mode, return -EACCES.
 */
int ima_file_mmap(struct file *file, unsigned long prot)
{
	if (file && (prot & PROT_EXEC))
		return process_measurement(file, NULL, 0, MAY_EXEC,
					   MMAP_CHECK, 0);
	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.
 *
 * On success return 0.  On integrity appraisal error, assuming the file
 * is in policy and IMA-appraisal is in enforcing mode, return -EACCES.
 */
int ima_bprm_check(struct linux_binprm *bprm)
{
	return process_measurement(bprm->file, NULL, 0, MAY_EXEC,
				   BPRM_CHECK, 0);
}

/**
 * ima_path_check - based on policy, collect/store measurement.
 * @file: pointer to the file to be measured
 * @mask: contains MAY_READ, MAY_WRITE, MAY_EXEC or MAY_APPEND
 *
 * Measure files based on the ima_must_measure() policy decision.
 *
 * On success return 0.  On integrity appraisal error, assuming the file
 * is in policy and IMA-appraisal is in enforcing mode, return -EACCES.
 */
int ima_file_check(struct file *file, int mask, int opened)
{
	return process_measurement(file, NULL, 0,
				   mask & (MAY_READ | MAY_WRITE | MAY_EXEC |
					   MAY_APPEND), FILE_CHECK, opened);
}
EXPORT_SYMBOL_GPL(ima_file_check);

/**
 * ima_post_path_mknod - mark as a new inode
 * @dentry: newly created dentry
 *
 * Mark files created via the mknodat syscall as new, so that the
 * file data can be written later.
 */
void ima_post_path_mknod(struct dentry *dentry)
{
	struct integrity_iint_cache *iint;
	struct inode *inode = dentry->d_inode;
	int must_appraise;

	must_appraise = ima_must_appraise(inode, MAY_ACCESS, FILE_CHECK);
	if (!must_appraise)
		return;

	iint = integrity_inode_get(inode);
	if (iint)
		iint->flags |= IMA_NEW_FILE;
}

/**
 * ima_read_file - pre-measure/appraise hook decision based on policy
 * @file: pointer to the file to be measured/appraised/audit
 * @read_id: caller identifier
 *
 * Permit reading a file based on policy. The policy rules are written
 * in terms of the policy identifier.  Appraising the integrity of
 * a file requires a file descriptor.
 *
 * For permission return 0, otherwise return -EACCES.
 */
int ima_read_file(struct file *file, enum kernel_read_file_id read_id)
{
	bool sig_enforce = is_module_sig_enforced();

	if (!file && read_id == READING_MODULE) {
		if (!sig_enforce && (ima_appraise & IMA_APPRAISE_MODULES) &&
		    (ima_appraise & IMA_APPRAISE_ENFORCE))
			return -EACCES;	/* INTEGRITY_UNKNOWN */
		return 0;	/* We rely on module signature checking */
	}
	return 0;
}

static int read_idmap[READING_MAX_ID] = {
	[READING_FIRMWARE] = FIRMWARE_CHECK,
	[READING_FIRMWARE_PREALLOC_BUFFER] = FIRMWARE_CHECK,
	[READING_MODULE] = MODULE_CHECK,
	[READING_KEXEC_IMAGE] = KEXEC_KERNEL_CHECK,
	[READING_KEXEC_INITRAMFS] = KEXEC_INITRAMFS_CHECK,
	[READING_POLICY] = POLICY_CHECK
};

/**
 * ima_post_read_file - in memory collect/appraise/audit measurement
 * @file: pointer to the file to be measured/appraised/audit
 * @buf: pointer to in memory file contents
 * @size: size of in memory file contents
 * @read_id: caller identifier
 *
 * Measure/appraise/audit in memory file based on policy.  Policy rules
 * are written in terms of a policy identifier.
 *
 * On success return 0.  On integrity appraisal error, assuming the file
 * is in policy and IMA-appraisal is in enforcing mode, return -EACCES.
 */
int ima_post_read_file(struct file *file, void *buf, loff_t size,
		       enum kernel_read_file_id read_id)
{
	enum ima_hooks func;

	if (!file && read_id == READING_FIRMWARE) {
		if ((ima_appraise & IMA_APPRAISE_FIRMWARE) &&
		    (ima_appraise & IMA_APPRAISE_ENFORCE))
			return -EACCES;	/* INTEGRITY_UNKNOWN */
		return 0;
	}

	if (!file && read_id == READING_MODULE) /* MODULE_SIG_FORCE enabled */
		return 0;

	/* permit signed certs */
	if (!file && read_id == READING_X509_CERTIFICATE)
		return 0;

	if (!file || !buf || size == 0) { /* should never happen */
		if (ima_appraise & IMA_APPRAISE_ENFORCE)
			return -EACCES;
		return 0;
	}

	func = read_idmap[read_id] ?: FILE_CHECK;
	return process_measurement(file, buf, size, MAY_READ, func, 0);
}

static int __init init_ima(void)
{
	int error;

	ima_init_template_list();
	hash_setup(CONFIG_IMA_DEFAULT_HASH);
	error = ima_init();

	if (error && strcmp(hash_algo_name[ima_hash_algo],
			    CONFIG_IMA_DEFAULT_HASH) != 0) {
		pr_info("Allocating %s failed, going to use default hash algorithm %s\n",
			hash_algo_name[ima_hash_algo], CONFIG_IMA_DEFAULT_HASH);
		hash_setup_done = 0;
		hash_setup(CONFIG_IMA_DEFAULT_HASH);
		error = ima_init();
	}

	if (!error) {
		ima_initialized = 1;
		ima_update_policy_flag();
	}
	return error;
}

late_initcall(init_ima);	/* Start IMA after the TPM is available */

MODULE_DESCRIPTION("Integrity Measurement Architecture");
MODULE_LICENSE("GPL");
Commit	Line	Data
3323eec9 MZ	1	/*
	2	* Copyright (C) 2005,2006,2007,2008 IBM Corporation
	3	*
	4	* Authors:
	5	* Reiner Sailer <sailer@watson.ibm.com>
	6	* Serge Hallyn <serue@us.ibm.com>
	7	* Kylene Hall <kylene@us.ibm.com>
	8	* Mimi Zohar <zohar@us.ibm.com>
	9	*
	10	* This program is free software; you can redistribute it and/or
	11	* modify it under the terms of the GNU General Public License as
	12	* published by the Free Software Foundation, version 2 of the
	13	* License.
	14	*
	15	* File: ima_main.c
e0d5bd2a	16	* implements the IMA hooks: ima_bprm_check, ima_file_mmap,
9bbb6cad	17	* and ima_file_check.
3323eec9	18	*/
8a048adc PV	19
	20	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
	21
3323eec9 MZ	22	#include <linux/module.h>
	23	#include <linux/file.h>
	24	#include <linux/binfmts.h>
	25	#include <linux/mount.h>
	26	#include <linux/mman.h>
5a0e3ad6	27	#include <linux/slab.h>
2fe5d6de	28	#include <linux/xattr.h>
d5813a57	29	#include <linux/ima.h>
3323eec9 MZ	30
	31	#include "ima.h"
	32
	33	int ima_initialized;
	34
2fe5d6de MZ	35	#ifdef CONFIG_IMA_APPRAISE
	36	int ima_appraise = IMA_APPRAISE_ENFORCE;
	37	#else
	38	int ima_appraise;
	39	#endif
	40
c7c8bb23	41	int ima_hash_algo = HASH_ALGO_SHA1;
e7a2ad7e	42	static int hash_setup_done;
c7c8bb23	43
3323eec9 MZ	44	static int __init hash_setup(char *str)
3323eec9 MZ	45	{
e7a2ad7e MZ	46	struct ima_template_desc *template_desc = ima_template_desc_current();
	47	int i;
	48
	49	if (hash_setup_done)
	50	return 1;
	51
	52	if (strcmp(template_desc->name, IMA_TEMPLATE_IMA_NAME) == 0) {
	53	if (strncmp(str, "sha1", 4) == 0)
	54	ima_hash_algo = HASH_ALGO_SHA1;
	55	else if (strncmp(str, "md5", 3) == 0)
	56	ima_hash_algo = HASH_ALGO_MD5;
ebe7c0a7 BW	57	else
ebe7c0a7 BW	58	return 1;
e7a2ad7e MZ	59	goto out;
	60	}
	61
	62	for (i = 0; i < HASH_ALGO__LAST; i++) {
	63	if (strcmp(str, hash_algo_name[i]) == 0) {
	64	ima_hash_algo = i;
	65	break;
	66	}
	67	}
ebe7c0a7 BW	68	if (i == HASH_ALGO__LAST)
ebe7c0a7 BW	69	return 1;
e7a2ad7e MZ	70	out:
e7a2ad7e MZ	71	hash_setup_done = 1;
3323eec9 MZ	72	return 1;
	73	}
	74	__setup("ima_hash=", hash_setup);
	75
8eb988c7	76	/*
890275b5	77	* ima_rdwr_violation_check
8eb988c7	78	*
890275b5	79	* Only invalidate the PCR for measured files:
2bb930ab	80	* - Opening a file for write when already open for read,
8eb988c7 MZ	81	* results in a time of measure, time of use (ToMToU) error.
8eb988c7 MZ	82	* - Opening a file for read when already open for write,
2bb930ab	83	* could result in a file measurement error.
8eb988c7 MZ	84	*
8eb988c7 MZ	85	*/
f7a859ff RS	86	static void ima_rdwr_violation_check(struct file *file,
f7a859ff RS	87	struct integrity_iint_cache *iint,
1b68bdf9	88	int must_measure,
f7a859ff RS	89	char **pathbuf,
f7a859ff RS	90	const char **pathname)
8eb988c7	91	{
c77cecee	92	struct inode *inode = file_inode(file);
bc15ed66	93	char filename[NAME_MAX];
8eb988c7	94	fmode_t mode = file->f_mode;
ad16ad00	95	bool send_tomtou = false, send_writers = false;
a178d202	96
8eb988c7	97	if (mode & FMODE_WRITE) {
14503eb9	98	if (atomic_read(&inode->i_readcount) && IS_IMA(inode)) {
f7a859ff RS	99	if (!iint)
f7a859ff RS	100	iint = integrity_iint_find(inode);
14503eb9	101	/* IMA_MEASURE is set from reader side */
493dbcec DK	102	if (iint && test_bit(IMA_MUST_MEASURE,
493dbcec DK	103	&iint->atomic_flags))
14503eb9 DK	104	send_tomtou = true;
14503eb9 DK	105	}
b882fae2	106	} else {
493dbcec DK	107	if (must_measure)
493dbcec DK	108	set_bit(IMA_MUST_MEASURE, &iint->atomic_flags);
1b68bdf9	109	if ((atomic_read(&inode->i_writecount) > 0) && must_measure)
b882fae2	110	send_writers = true;
8eb988c7	111	}
ad16ad00	112
08e1b76a MZ	113	if (!send_tomtou && !send_writers)
	114	return;
	115
bc15ed66	116	*pathname = ima_d_path(&file->f_path, pathbuf, filename);
ea1046d4	117
ad16ad00	118	if (send_tomtou)
8d94eb9b RS	119	ima_add_violation(file, *pathname, iint,
8d94eb9b RS	120	"invalid_pcr", "ToMToU");
ad16ad00	121	if (send_writers)
8d94eb9b	122	ima_add_violation(file, *pathname, iint,
08e1b76a	123	"invalid_pcr", "open_writers");
8eb988c7 MZ	124	}
8eb988c7 MZ	125
f381c272	126	static void ima_check_last_writer(struct integrity_iint_cache *iint,
2fe5d6de	127	struct inode inode, struct file file)
bc7d2a3e	128	{
4b2a2c67	129	fmode_t mode = file->f_mode;
493dbcec	130	bool update;
bc7d2a3e	131
2fe5d6de MZ	132	if (!(mode & FMODE_WRITE))
	133	return;
	134
493dbcec	135	mutex_lock(&iint->mutex);
b151d6b0	136	if (atomic_read(&inode->i_writecount) == 1) {
493dbcec DK	137	update = test_and_clear_bit(IMA_UPDATE_XATTR,
493dbcec DK	138	&iint->atomic_flags);
b151d6b0 DK	139	if ((iint->version != inode->i_version) \|\|
	140	(iint->flags & IMA_NEW_FILE)) {
	141	iint->flags &= ~(IMA_DONE_MASK \| IMA_NEW_FILE);
a422638d	142	iint->measured_pcrs = 0;
493dbcec	143	if (update)
b151d6b0 DK	144	ima_update_xattr(iint, file);
b151d6b0 DK	145	}
2fe5d6de	146	}
493dbcec	147	mutex_unlock(&iint->mutex);
bc7d2a3e EP	148	}
bc7d2a3e EP	149
3323eec9 MZ	150	/**
	151	* ima_file_free - called on __fput()
	152	* @file: pointer to file structure being freed
	153	*
890275b5	154	* Flag files that changed, based on i_version
3323eec9 MZ	155	*/
	156	void ima_file_free(struct file *file)
	157	{
496ad9aa	158	struct inode *inode = file_inode(file);
f381c272	159	struct integrity_iint_cache *iint;
3323eec9	160
0f34a006	161	if (!ima_policy_flag \|\| !S_ISREG(inode->i_mode))
3323eec9	162	return;
196f5181	163
f381c272	164	iint = integrity_iint_find(inode);
854fdd55 MZ	165	if (!iint)
854fdd55 MZ	166	return;
3323eec9	167
854fdd55	168	ima_check_last_writer(iint, inode, file);
3323eec9 MZ	169	}
3323eec9 MZ	170
cf222217 MZ	171	static int process_measurement(struct file file, char buf, loff_t size,
cf222217 MZ	172	int mask, enum ima_hooks func, int opened)
3323eec9	173	{
496ad9aa	174	struct inode *inode = file_inode(file);
f7a859ff	175	struct integrity_iint_cache *iint = NULL;
209b43ca	176	struct ima_template_desc *template_desc;
ea1046d4	177	char *pathbuf = NULL;
bc15ed66	178	char filename[NAME_MAX];
ea1046d4	179	const char *pathname = NULL;
493dbcec	180	int rc = 0, action, must_appraise = 0;
725de7fa	181	int pcr = CONFIG_IMA_MEASURE_PCR_IDX;
1525b06d	182	struct evm_ima_xattr_data *xattr_value = NULL;
d3634d0f	183	int xattr_len = 0;
f7a859ff	184	bool violation_check;
1525b06d	185	enum hash_algo hash_algo;
3323eec9	186
a756024e	187	if (!ima_policy_flag \|\| !S_ISREG(inode->i_mode))
3323eec9	188	return 0;
bc7d2a3e	189
d79d72e0 MZ	190	/* Return an IMA_MEASURE, IMA_APPRAISE, IMA_AUDIT action
	191	* bitmask based on the appraise/audit/measurement policy.
	192	* Included is the appraise submask.
	193	*/
725de7fa	194	action = ima_get_action(inode, mask, func, &pcr);
4ad87a3d	195	violation_check = ((func == FILE_CHECK \|\| func == MMAP_CHECK) &&
f7a859ff RS	196	(ima_policy_flag & IMA_MEASURE));
f7a859ff RS	197	if (!action && !violation_check)
2fe5d6de MZ	198	return 0;
2fe5d6de MZ	199
2fe5d6de	200	must_appraise = action & IMA_APPRAISE;
bc7d2a3e	201
5a73fcfa	202	/* Is the appraise rule hook specific? */
3a8a2ead	203	if (action & IMA_FILE_APPRAISE)
4ad87a3d	204	func = FILE_CHECK;
5a73fcfa	205
5955102c	206	inode_lock(inode);
2fe5d6de	207
f7a859ff RS	208	if (action) {
	209	iint = integrity_inode_get(inode);
	210	if (!iint)
493dbcec	211	rc = -ENOMEM;
f7a859ff RS	212	}
f7a859ff RS	213
493dbcec	214	if (!rc && violation_check)
1b68bdf9 RS	215	ima_rdwr_violation_check(file, iint, action & IMA_MEASURE,
1b68bdf9 RS	216	&pathbuf, &pathname);
493dbcec DK	217
	218	inode_unlock(inode);
	219
	220	if (rc)
	221	goto out;
	222	if (!action)
	223	goto out;
	224
	225	mutex_lock(&iint->mutex);
	226
	227	if (test_and_clear_bit(IMA_CHANGE_ATTR, &iint->atomic_flags))
	228	/* reset appraisal flags if ima_inode_post_setattr was called */
	229	iint->flags &= ~(IMA_APPRAISE \| IMA_APPRAISED \|
	230	IMA_APPRAISE_SUBMASK \| IMA_APPRAISED_SUBMASK \|
	231	IMA_ACTION_FLAGS);
	232
	233	if (test_and_clear_bit(IMA_CHANGE_XATTR, &iint->atomic_flags))
	234	/* reset all flags if ima_inode_setxattr was called */
	235	iint->flags &= ~IMA_DONE_MASK;
bf2276d1	236
2fe5d6de	237	/* Determine if already appraised/measured based on bitmask
d79d72e0 MZ	238	* (IMA_MEASURE, IMA_MEASURED, IMA_XXXX_APPRAISE, IMA_XXXX_APPRAISED,
	239	* IMA_AUDIT, IMA_AUDITED)
	240	*/
2fe5d6de	241	iint->flags \|= action;
0e5a247c	242	action &= IMA_DO_MASK;
a422638d ER	243	action &= ~((iint->flags & (IMA_DONE_MASK ^ IMA_MEASURED)) >> 1);
	244
	245	/* If target pcr is already measured, unset IMA_MEASURE action */
	246	if ((action & IMA_MEASURE) && (iint->measured_pcrs & (0x1 << pcr)))
	247	action ^= IMA_MEASURE;
2fe5d6de MZ	248
	249	/* Nothing to do, just return existing appraised status */
	250	if (!action) {
d79d72e0	251	if (must_appraise)
4ad87a3d	252	rc = ima_get_cache_status(iint, func);
493dbcec	253	goto out_locked;
2fe5d6de	254	}
3323eec9	255
209b43ca	256	template_desc = ima_template_desc_current();
f68c05f4 DK	257	if ((action & IMA_APPRAISE_SUBMASK) \|\|
f68c05f4 DK	258	strcmp(template_desc->name, IMA_TEMPLATE_IMA_NAME) != 0)
1525b06d	259	/* read 'security.ima' */
e71b9dff	260	xattr_len = ima_read_xattr(file_dentry(file), &xattr_value);
d3634d0f	261
1525b06d DK	262	hash_algo = ima_get_hash_algo(xattr_value, xattr_len);
1525b06d DK	263
cf222217	264	rc = ima_collect_measurement(iint, file, buf, size, hash_algo);
f3cc6b25	265	if (rc != 0 && rc != -EBADF && rc != -EINVAL)
493dbcec	266	goto out_locked;
08e1b76a	267
bc15ed66 MZ	268	if (!pathbuf) /* ima_rdwr_violation possibly pre-fetched */
bc15ed66 MZ	269	pathname = ima_d_path(&file->f_path, &pathbuf, filename);
08e1b76a	270
2fe5d6de	271	if (action & IMA_MEASURE)
bcbc9b0c	272	ima_store_measurement(iint, file, pathname,
14b1da85	273	xattr_value, xattr_len, pcr);
493dbcec DK	274	if (rc == 0 && (action & IMA_APPRAISE_SUBMASK)) {
493dbcec DK	275	inode_lock(inode);
4ad87a3d	276	rc = ima_appraise_measurement(func, iint, file, pathname,
3034a146	277	xattr_value, xattr_len, opened);
493dbcec DK	278	inode_unlock(inode);
493dbcec DK	279	}
e7c568e0	280	if (action & IMA_AUDIT)
ea1046d4	281	ima_audit_measurement(iint, pathname);
f7a859ff	282
f3cc6b25 MZ	283	if ((file->f_flags & O_DIRECT) && (iint->flags & IMA_PERMIT_DIRECTIO))
f3cc6b25 MZ	284	rc = 0;
493dbcec DK	285	out_locked:
493dbcec DK	286	if ((mask & MAY_WRITE) && test_bit(IMA_DIGSIG, &iint->atomic_flags) &&
05d1a717	287	!(iint->flags & IMA_NEW_FILE))
a175b8bb	288	rc = -EACCES;
493dbcec	289	mutex_unlock(&iint->mutex);
f7a859ff	290	kfree(xattr_value);
493dbcec	291	out:
456f5fd3 DK	292	if (pathbuf)
456f5fd3 DK	293	__putname(pathbuf);
493dbcec DK	294	if (must_appraise) {
	295	if (rc && (ima_appraise & IMA_APPRAISE_ENFORCE))
	296	return -EACCES;
	297	if (file->f_mode & FMODE_WRITE)
	298	set_bit(IMA_UPDATE_XATTR, &iint->atomic_flags);
	299	}
750943a3	300	return 0;
3323eec9 MZ	301	}
	302
	303	/**
	304	* ima_file_mmap - based on policy, collect/store measurement.
	305	* @file: pointer to the file to be measured (May be NULL)
	306	* @prot: contains the protection that will be applied by the kernel.
	307	*
	308	* Measure files being mmapped executable based on the ima_must_measure()
	309	* policy decision.
	310	*
750943a3 DK	311	* On success return 0. On integrity appraisal error, assuming the file
750943a3 DK	312	* is in policy and IMA-appraisal is in enforcing mode, return -EACCES.
3323eec9 MZ	313	*/
	314	int ima_file_mmap(struct file *file, unsigned long prot)
	315	{
750943a3	316	if (file && (prot & PROT_EXEC))
cf222217 MZ	317	return process_measurement(file, NULL, 0, MAY_EXEC,
cf222217 MZ	318	MMAP_CHECK, 0);
750943a3	319	return 0;
3323eec9 MZ	320	}
	321
	322	/**
	323	* ima_bprm_check - based on policy, collect/store measurement.
	324	* @bprm: contains the linux_binprm structure
	325	*
	326	* The OS protects against an executable file, already open for write,
	327	* from being executed in deny_write_access() and an executable file,
	328	* already open for execute, from being modified in get_write_access().
	329	* So we can be certain that what we verify and measure here is actually
	330	* what is being executed.
	331	*
750943a3 DK	332	* On success return 0. On integrity appraisal error, assuming the file
750943a3 DK	333	* is in policy and IMA-appraisal is in enforcing mode, return -EACCES.
3323eec9 MZ	334	*/
	335	int ima_bprm_check(struct linux_binprm *bprm)
	336	{
cf222217 MZ	337	return process_measurement(bprm->file, NULL, 0, MAY_EXEC,
cf222217 MZ	338	BPRM_CHECK, 0);
3323eec9 MZ	339	}
3323eec9 MZ	340
8eb988c7 MZ	341	/**
	342	* ima_path_check - based on policy, collect/store measurement.
	343	* @file: pointer to the file to be measured
20f482ab	344	* @mask: contains MAY_READ, MAY_WRITE, MAY_EXEC or MAY_APPEND
8eb988c7 MZ	345	*
	346	* Measure files based on the ima_must_measure() policy decision.
	347	*
750943a3 DK	348	* On success return 0. On integrity appraisal error, assuming the file
750943a3 DK	349	* is in policy and IMA-appraisal is in enforcing mode, return -EACCES.
8eb988c7	350	*/
3034a146	351	int ima_file_check(struct file *file, int mask, int opened)
8eb988c7	352	{
cf222217	353	return process_measurement(file, NULL, 0,
20f482ab LZ	354	mask & (MAY_READ \| MAY_WRITE \| MAY_EXEC \|
20f482ab LZ	355	MAY_APPEND), FILE_CHECK, opened);
8eb988c7	356	}
9bbb6cad	357	EXPORT_SYMBOL_GPL(ima_file_check);
8eb988c7	358
05d1a717 MZ	359	/**
	360	* ima_post_path_mknod - mark as a new inode
	361	* @dentry: newly created dentry
	362	*
	363	* Mark files created via the mknodat syscall as new, so that the
	364	* file data can be written later.
	365	*/
	366	void ima_post_path_mknod(struct dentry *dentry)
	367	{
	368	struct integrity_iint_cache *iint;
	369	struct inode *inode = dentry->d_inode;
	370	int must_appraise;
	371
	372	must_appraise = ima_must_appraise(inode, MAY_ACCESS, FILE_CHECK);
	373	if (!must_appraise)
	374	return;
	375
	376	iint = integrity_inode_get(inode);
	377	if (iint)
	378	iint->flags \|= IMA_NEW_FILE;
	379	}
	380
39eeb4fb MZ	381	/**
	382	* ima_read_file - pre-measure/appraise hook decision based on policy
	383	* @file: pointer to the file to be measured/appraised/audit
	384	* @read_id: caller identifier
	385	*
	386	* Permit reading a file based on policy. The policy rules are written
	387	* in terms of the policy identifier. Appraising the integrity of
	388	* a file requires a file descriptor.
	389	*
	390	* For permission return 0, otherwise return -EACCES.
	391	*/
	392	int ima_read_file(struct file *file, enum kernel_read_file_id read_id)
	393	{
7c9bc098 BM	394	bool sig_enforce = is_module_sig_enforced();
7c9bc098 BM	395
a1db7420	396	if (!file && read_id == READING_MODULE) {
7c9bc098	397	if (!sig_enforce && (ima_appraise & IMA_APPRAISE_MODULES) &&
a1db7420 MZ	398	(ima_appraise & IMA_APPRAISE_ENFORCE))
a1db7420 MZ	399	return -EACCES; /* INTEGRITY_UNKNOWN */
a1db7420 MZ	400	return 0; /* We rely on module signature checking */
a1db7420 MZ	401	}
39eeb4fb MZ	402	return 0;
	403	}
	404
d9ddf077 MZ	405	static int read_idmap[READING_MAX_ID] = {
d9ddf077 MZ	406	[READING_FIRMWARE] = FIRMWARE_CHECK,
88d941dc	407	[READING_FIRMWARE_PREALLOC_BUFFER] = FIRMWARE_CHECK,
d9ddf077 MZ	408	[READING_MODULE] = MODULE_CHECK,
	409	[READING_KEXEC_IMAGE] = KEXEC_KERNEL_CHECK,
	410	[READING_KEXEC_INITRAMFS] = KEXEC_INITRAMFS_CHECK,
19f8a847	411	[READING_POLICY] = POLICY_CHECK
d9ddf077 MZ	412	};
d9ddf077 MZ	413
cf222217 MZ	414	/**
	415	* ima_post_read_file - in memory collect/appraise/audit measurement
	416	* @file: pointer to the file to be measured/appraised/audit
	417	* @buf: pointer to in memory file contents
	418	* @size: size of in memory file contents
	419	* @read_id: caller identifier
	420	*
	421	* Measure/appraise/audit in memory file based on policy. Policy rules
	422	* are written in terms of a policy identifier.
	423	*
	424	* On success return 0. On integrity appraisal error, assuming the file
	425	* is in policy and IMA-appraisal is in enforcing mode, return -EACCES.
	426	*/
	427	int ima_post_read_file(struct file file, void buf, loff_t size,
	428	enum kernel_read_file_id read_id)
	429	{
d9ddf077	430	enum ima_hooks func;
cf222217	431
e40ba6d5 MZ	432	if (!file && read_id == READING_FIRMWARE) {
	433	if ((ima_appraise & IMA_APPRAISE_FIRMWARE) &&
	434	(ima_appraise & IMA_APPRAISE_ENFORCE))
	435	return -EACCES; /* INTEGRITY_UNKNOWN */
	436	return 0;
	437	}
	438
a1db7420 MZ	439	if (!file && read_id == READING_MODULE) /* MODULE_SIG_FORCE enabled */
	440	return 0;
	441
a7d3d039 CH	442	/* permit signed certs */
	443	if (!file && read_id == READING_X509_CERTIFICATE)
	444	return 0;
	445
cf222217 MZ	446	if (!file \|\| !buf \|\| size == 0) { /* should never happen */
	447	if (ima_appraise & IMA_APPRAISE_ENFORCE)
	448	return -EACCES;
	449	return 0;
	450	}
	451
d9ddf077	452	func = read_idmap[read_id] ?: FILE_CHECK;
cf222217	453	return process_measurement(file, buf, size, MAY_READ, func, 0);
5a9196d7 MZ	454	}
5a9196d7 MZ	455
3323eec9 MZ	456	static int __init init_ima(void)
	457	{
	458	int error;
	459
3f23d624	460	ima_init_template_list();
e7a2ad7e	461	hash_setup(CONFIG_IMA_DEFAULT_HASH);
3323eec9	462	error = ima_init();
8a048adc PV	463
	464	if (error && strcmp(hash_algo_name[ima_hash_algo],
	465	CONFIG_IMA_DEFAULT_HASH) != 0) {
	466	pr_info("Allocating %s failed, going to use default hash algorithm %s\n",
	467	hash_algo_name[ima_hash_algo], CONFIG_IMA_DEFAULT_HASH);
	468	hash_setup_done = 0;
	469	hash_setup(CONFIG_IMA_DEFAULT_HASH);
	470	error = ima_init();
	471	}
	472
a756024e	473	if (!error) {
31b70f66	474	ima_initialized = 1;
a756024e RS	475	ima_update_policy_flag();
a756024e RS	476	}
3323eec9 MZ	477	return error;
	478	}
	479
	480	late_initcall(init_ima); /* Start IMA after the TPM is available */
	481
	482	MODULE_DESCRIPTION("Integrity Measurement Architecture");
	483	MODULE_LICENSE("GPL");