[mirror_ubuntu-artful-kernel.git] / security / integrity / evm / evm_main.c

/*
 * Copyright (C) 2005-2010 IBM Corporation
 *
 * Author:
 * 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: evm_main.c
 *	implements evm_inode_setxattr, evm_inode_post_setxattr,
 *	evm_inode_removexattr, and evm_verifyxattr
 */

#include <linux/module.h>
#include <linux/crypto.h>
#include <linux/xattr.h>
#include <linux/integrity.h>
#include <linux/evm.h>
#include <crypto/hash.h>
#include "evm.h"

int evm_initialized;

char *evm_hmac = "hmac(sha1)";

char *evm_config_xattrnames[] = {
#ifdef CONFIG_SECURITY_SELINUX
	XATTR_NAME_SELINUX,
#endif
#ifdef CONFIG_SECURITY_SMACK
	XATTR_NAME_SMACK,
#endif
	XATTR_NAME_CAPS,
	NULL
};

static int evm_fixmode;
static int __init evm_set_fixmode(char *str)
{
	if (strncmp(str, "fix", 3) == 0)
		evm_fixmode = 1;
	return 0;
}
__setup("evm=", evm_set_fixmode);

/*
 * evm_verify_hmac - calculate and compare the HMAC with the EVM xattr
 *
 * Compute the HMAC on the dentry's protected set of extended attributes
 * and compare it against the stored security.evm xattr.
 *
 * For performance:
 * - use the previoulsy retrieved xattr value and length to calculate the
 *   HMAC.)
 * - cache the verification result in the iint, when available.
 *
 * Returns integrity status
 */
static enum integrity_status evm_verify_hmac(struct dentry *dentry,
					     const char *xattr_name,
					     char *xattr_value,
					     size_t xattr_value_len,
					     struct integrity_iint_cache *iint)
{
	struct evm_ima_xattr_data xattr_data;
	enum integrity_status evm_status;
	int rc;

	if (iint && iint->evm_status == INTEGRITY_PASS)
		return iint->evm_status;

	/* if status is not PASS, try to check again - against -ENOMEM */

	rc = evm_calc_hmac(dentry, xattr_name, xattr_value,
			   xattr_value_len, xattr_data.digest);
	if (rc < 0)
		goto err_out;

	xattr_data.type = EVM_XATTR_HMAC;
	rc = vfs_xattr_cmp(dentry, XATTR_NAME_EVM, (u8 *)&xattr_data,
			   sizeof xattr_data, GFP_NOFS);
	if (rc < 0)
		goto err_out;
	evm_status = INTEGRITY_PASS;
	goto out;

err_out:
	switch (rc) {
	case -ENODATA:		/* file not labelled */
		evm_status = INTEGRITY_NOLABEL;
		break;
	default:
		evm_status = INTEGRITY_FAIL;
	}
out:
	if (iint)
		iint->evm_status = evm_status;
	return evm_status;
}

static int evm_protected_xattr(const char *req_xattr_name)
{
	char **xattrname;
	int namelen;
	int found = 0;

	namelen = strlen(req_xattr_name);
	for (xattrname = evm_config_xattrnames; *xattrname != NULL; xattrname++) {
		if ((strlen(*xattrname) == namelen)
		    && (strncmp(req_xattr_name, *xattrname, namelen) == 0)) {
			found = 1;
			break;
		}
		if (strncmp(req_xattr_name,
			    *xattrname + XATTR_SECURITY_PREFIX_LEN,
			    strlen(req_xattr_name)) == 0) {
			found = 1;
			break;
		}
	}
	return found;
}

/**
 * evm_verifyxattr - verify the integrity of the requested xattr
 * @dentry: object of the verify xattr
 * @xattr_name: requested xattr
 * @xattr_value: requested xattr value
 * @xattr_value_len: requested xattr value length
 *
 * Calculate the HMAC for the given dentry and verify it against the stored
 * security.evm xattr. For performance, use the xattr value and length
 * previously retrieved to calculate the HMAC.
 *
 * Returns the xattr integrity status.
 *
 * This function requires the caller to lock the inode's i_mutex before it
 * is executed.
 */
enum integrity_status evm_verifyxattr(struct dentry *dentry,
				      const char *xattr_name,
				      void *xattr_value, size_t xattr_value_len,
				      struct integrity_iint_cache *iint)
{
	if (!evm_initialized || !evm_protected_xattr(xattr_name))
		return INTEGRITY_UNKNOWN;

	if (!iint) {
		iint = integrity_iint_find(dentry->d_inode);
		if (!iint)
			return INTEGRITY_UNKNOWN;
	}
	return evm_verify_hmac(dentry, xattr_name, xattr_value,
				 xattr_value_len, iint);
}
EXPORT_SYMBOL_GPL(evm_verifyxattr);

/*
 * evm_verify_current_integrity - verify the dentry's metadata integrity
 * @dentry: pointer to the affected dentry
 *
 * Verify and return the dentry's metadata integrity. The exceptions are
 * before EVM is initialized or in 'fix' mode.
 */
static enum integrity_status evm_verify_current_integrity(struct dentry *dentry)
{
	struct inode *inode = dentry->d_inode;

	if (!evm_initialized || !S_ISREG(inode->i_mode) || evm_fixmode)
		return 0;
	return evm_verify_hmac(dentry, NULL, NULL, 0, NULL);
}

/*
 * evm_protect_xattr - protect the EVM extended attribute
 *
 * Prevent security.evm from being modified or removed without the
 * necessary permissions or when the existing value is invalid.
 *
 * The posix xattr acls are 'system' prefixed, which normally would not
 * affect security.evm.  An interesting side affect of writing posix xattr
 * acls is their modifying of the i_mode, which is included in security.evm.
 * For posix xattr acls only, permit security.evm, even if it currently
 * doesn't exist, to be updated.
 */
static int evm_protect_xattr(struct dentry *dentry, const char *xattr_name,
			     const void *xattr_value, size_t xattr_value_len)
{
	enum integrity_status evm_status;

	if (strcmp(xattr_name, XATTR_NAME_EVM) == 0) {
		if (!capable(CAP_SYS_ADMIN))
			return -EPERM;
	} else if (!evm_protected_xattr(xattr_name)) {
		if (!posix_xattr_acl(xattr_name))
			return 0;
		evm_status = evm_verify_current_integrity(dentry);
		if ((evm_status == INTEGRITY_PASS) ||
			(evm_status == INTEGRITY_NOLABEL))
			return 0;
		return -EPERM;
	}
	evm_status = evm_verify_current_integrity(dentry);
	return evm_status == INTEGRITY_PASS ? 0 : -EPERM;
}

/**
 * evm_inode_setxattr - protect the EVM extended attribute
 * @dentry: pointer to the affected dentry
 * @xattr_name: pointer to the affected extended attribute name
 * @xattr_value: pointer to the new extended attribute value
 * @xattr_value_len: pointer to the new extended attribute value length
 *
 * Updating 'security.evm' requires CAP_SYS_ADMIN privileges and that
 * the current value is valid.
 */
int evm_inode_setxattr(struct dentry *dentry, const char *xattr_name,
		       const void *xattr_value, size_t xattr_value_len)
{
	return evm_protect_xattr(dentry, xattr_name, xattr_value,
				 xattr_value_len);
}

/**
 * evm_inode_removexattr - protect the EVM extended attribute
 * @dentry: pointer to the affected dentry
 * @xattr_name: pointer to the affected extended attribute name
 *
 * Removing 'security.evm' requires CAP_SYS_ADMIN privileges and that
 * the current value is valid.
 */
int evm_inode_removexattr(struct dentry *dentry, const char *xattr_name)
{
	return evm_protect_xattr(dentry, xattr_name, NULL, 0);
}

/**
 * evm_inode_post_setxattr - update 'security.evm' to reflect the changes
 * @dentry: pointer to the affected dentry
 * @xattr_name: pointer to the affected extended attribute name
 * @xattr_value: pointer to the new extended attribute value
 * @xattr_value_len: pointer to the new extended attribute value length
 *
 * Update the HMAC stored in 'security.evm' to reflect the change.
 *
 * No need to take the i_mutex lock here, as this function is called from
 * __vfs_setxattr_noperm().  The caller of which has taken the inode's
 * i_mutex lock.
 */
void evm_inode_post_setxattr(struct dentry *dentry, const char *xattr_name,
			     const void *xattr_value, size_t xattr_value_len)
{
	if (!evm_initialized || (!evm_protected_xattr(xattr_name)
				 && !posix_xattr_acl(xattr_name)))
		return;

	evm_update_evmxattr(dentry, xattr_name, xattr_value, xattr_value_len);
	return;
}

/**
 * evm_inode_post_removexattr - update 'security.evm' after removing the xattr
 * @dentry: pointer to the affected dentry
 * @xattr_name: pointer to the affected extended attribute name
 *
 * Update the HMAC stored in 'security.evm' to reflect removal of the xattr.
 */
void evm_inode_post_removexattr(struct dentry *dentry, const char *xattr_name)
{
	struct inode *inode = dentry->d_inode;

	if (!evm_initialized || !evm_protected_xattr(xattr_name))
		return;

	mutex_lock(&inode->i_mutex);
	evm_update_evmxattr(dentry, xattr_name, NULL, 0);
	mutex_unlock(&inode->i_mutex);
	return;
}

/**
 * evm_inode_setattr - prevent updating an invalid EVM extended attribute
 * @dentry: pointer to the affected dentry
 */
int evm_inode_setattr(struct dentry *dentry, struct iattr *attr)
{
	unsigned int ia_valid = attr->ia_valid;
	enum integrity_status evm_status;

	if (!(ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID)))
		return 0;
	evm_status = evm_verify_current_integrity(dentry);
	return evm_status == INTEGRITY_PASS ? 0 : -EPERM;
}

/**
 * evm_inode_post_setattr - update 'security.evm' after modifying metadata
 * @dentry: pointer to the affected dentry
 * @ia_valid: for the UID and GID status
 *
 * For now, update the HMAC stored in 'security.evm' to reflect UID/GID
 * changes.
 *
 * This function is called from notify_change(), which expects the caller
 * to lock the inode's i_mutex.
 */
void evm_inode_post_setattr(struct dentry *dentry, int ia_valid)
{
	if (!evm_initialized)
		return;

	if (ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID))
		evm_update_evmxattr(dentry, NULL, NULL, 0);
	return;
}

/*
 * evm_inode_init_security - initializes security.evm
 */
int evm_inode_init_security(struct inode *inode,
				 const struct xattr *lsm_xattr,
				 struct xattr *evm_xattr)
{
	struct evm_ima_xattr_data *xattr_data;
	int rc;

	if (!evm_initialized || !evm_protected_xattr(lsm_xattr->name))
		return 0;

	xattr_data = kzalloc(sizeof(*xattr_data), GFP_NOFS);
	if (!xattr_data)
		return -ENOMEM;

	xattr_data->type = EVM_XATTR_HMAC;
	rc = evm_init_hmac(inode, lsm_xattr, xattr_data->digest);
	if (rc < 0)
		goto out;

	evm_xattr->value = xattr_data;
	evm_xattr->value_len = sizeof(*xattr_data);
	evm_xattr->name = kstrdup(XATTR_EVM_SUFFIX, GFP_NOFS);
	return 0;
out:
	kfree(xattr_data);
	return rc;
}
EXPORT_SYMBOL_GPL(evm_inode_init_security);

static int __init init_evm(void)
{
	int error;

	error = evm_init_secfs();
	if (error < 0) {
		printk(KERN_INFO "EVM: Error registering secfs\n");
		goto err;
	}
err:
	return error;
}

static void __exit cleanup_evm(void)
{
	evm_cleanup_secfs();
	if (hmac_tfm)
		crypto_free_shash(hmac_tfm);
}

/*
 * evm_display_config - list the EVM protected security extended attributes
 */
static int __init evm_display_config(void)
{
	char **xattrname;

	for (xattrname = evm_config_xattrnames; *xattrname != NULL; xattrname++)
		printk(KERN_INFO "EVM: %s\n", *xattrname);
	return 0;
}

pure_initcall(evm_display_config);
late_initcall(init_evm);

MODULE_DESCRIPTION("Extended Verification Module");
MODULE_LICENSE("GPL");
Commit	Line	Data
66dbc325 MZ	1	/*
	2	* Copyright (C) 2005-2010 IBM Corporation
	3	*
	4	* Author:
	5	* Mimi Zohar <zohar@us.ibm.com>
	6	* Kylene Hall <kjhall@us.ibm.com>
	7	*
	8	* This program is free software; you can redistribute it and/or modify
	9	* it under the terms of the GNU General Public License as published by
	10	* the Free Software Foundation, version 2 of the License.
	11	*
	12	* File: evm_main.c
	13	* implements evm_inode_setxattr, evm_inode_post_setxattr,
	14	* evm_inode_removexattr, and evm_verifyxattr
	15	*/
	16
	17	#include <linux/module.h>
	18	#include <linux/crypto.h>
	19	#include <linux/xattr.h>
	20	#include <linux/integrity.h>
3e1be52d	21	#include <linux/evm.h>
d46eb369	22	#include <crypto/hash.h>
66dbc325 MZ	23	#include "evm.h"
	24
	25	int evm_initialized;
	26
	27	char *evm_hmac = "hmac(sha1)";
	28
	29	char *evm_config_xattrnames[] = {
	30	#ifdef CONFIG_SECURITY_SELINUX
	31	XATTR_NAME_SELINUX,
	32	#endif
	33	#ifdef CONFIG_SECURITY_SMACK
	34	XATTR_NAME_SMACK,
	35	#endif
	36	XATTR_NAME_CAPS,
	37	NULL
	38	};
	39
7102ebcd MZ	40	static int evm_fixmode;
	41	static int __init evm_set_fixmode(char *str)
	42	{
	43	if (strncmp(str, "fix", 3) == 0)
	44	evm_fixmode = 1;
	45	return 0;
	46	}
	47	__setup("evm=", evm_set_fixmode);
	48
66dbc325 MZ	49	/*
	50	* evm_verify_hmac - calculate and compare the HMAC with the EVM xattr
	51	*
	52	* Compute the HMAC on the dentry's protected set of extended attributes
7102ebcd MZ	53	* and compare it against the stored security.evm xattr.
	54	*
	55	* For performance:
	56	* - use the previoulsy retrieved xattr value and length to calculate the
	57	* HMAC.)
	58	* - cache the verification result in the iint, when available.
66dbc325 MZ	59	*
	60	* Returns integrity status
	61	*/
	62	static enum integrity_status evm_verify_hmac(struct dentry *dentry,
	63	const char *xattr_name,
	64	char *xattr_value,
	65	size_t xattr_value_len,
	66	struct integrity_iint_cache *iint)
	67	{
6be5cc52	68	struct evm_ima_xattr_data xattr_data;
7102ebcd	69	enum integrity_status evm_status;
66dbc325 MZ	70	int rc;
66dbc325 MZ	71
7102ebcd	72	if (iint && iint->evm_status == INTEGRITY_PASS)
24e0198e	73	return iint->evm_status;
66dbc325	74
6d38ca01 DK	75	/* if status is not PASS, try to check again - against -ENOMEM */
6d38ca01 DK	76
66dbc325	77	rc = evm_calc_hmac(dentry, xattr_name, xattr_value,
6be5cc52	78	xattr_value_len, xattr_data.digest);
66dbc325	79	if (rc < 0)
6d38ca01	80	goto err_out;
66dbc325	81
6be5cc52 DK	82	xattr_data.type = EVM_XATTR_HMAC;
	83	rc = vfs_xattr_cmp(dentry, XATTR_NAME_EVM, (u8 *)&xattr_data,
	84	sizeof xattr_data, GFP_NOFS);
66dbc325 MZ	85	if (rc < 0)
66dbc325 MZ	86	goto err_out;
7102ebcd MZ	87	evm_status = INTEGRITY_PASS;
7102ebcd MZ	88	goto out;
66dbc325 MZ	89
	90	err_out:
	91	switch (rc) {
	92	case -ENODATA: /* file not labelled */
7102ebcd	93	evm_status = INTEGRITY_NOLABEL;
66dbc325	94	break;
66dbc325	95	default:
7102ebcd	96	evm_status = INTEGRITY_FAIL;
66dbc325	97	}
7102ebcd MZ	98	out:
	99	if (iint)
	100	iint->evm_status = evm_status;
	101	return evm_status;
66dbc325 MZ	102	}
	103
	104	static int evm_protected_xattr(const char *req_xattr_name)
	105	{
	106	char **xattrname;
	107	int namelen;
	108	int found = 0;
	109
	110	namelen = strlen(req_xattr_name);
	111	for (xattrname = evm_config_xattrnames; *xattrname != NULL; xattrname++) {
	112	if ((strlen(*xattrname) == namelen)
	113	&& (strncmp(req_xattr_name, *xattrname, namelen) == 0)) {
	114	found = 1;
	115	break;
	116	}
cb723180 MZ	117	if (strncmp(req_xattr_name,
	118	*xattrname + XATTR_SECURITY_PREFIX_LEN,
	119	strlen(req_xattr_name)) == 0) {
	120	found = 1;
	121	break;
	122	}
66dbc325 MZ	123	}
	124	return found;
	125	}
	126
	127	/**
	128	* evm_verifyxattr - verify the integrity of the requested xattr
	129	* @dentry: object of the verify xattr
	130	* @xattr_name: requested xattr
	131	* @xattr_value: requested xattr value
	132	* @xattr_value_len: requested xattr value length
	133	*
	134	* Calculate the HMAC for the given dentry and verify it against the stored
	135	* security.evm xattr. For performance, use the xattr value and length
	136	* previously retrieved to calculate the HMAC.
	137	*
	138	* Returns the xattr integrity status.
	139	*
	140	* This function requires the caller to lock the inode's i_mutex before it
	141	* is executed.
	142	*/
	143	enum integrity_status evm_verifyxattr(struct dentry *dentry,
	144	const char *xattr_name,
2960e6cb DK	145	void *xattr_value, size_t xattr_value_len,
2960e6cb DK	146	struct integrity_iint_cache *iint)
66dbc325	147	{
66dbc325 MZ	148	if (!evm_initialized \|\| !evm_protected_xattr(xattr_name))
	149	return INTEGRITY_UNKNOWN;
	150
2960e6cb DK	151	if (!iint) {
	152	iint = integrity_iint_find(dentry->d_inode);
	153	if (!iint)
	154	return INTEGRITY_UNKNOWN;
	155	}
	156	return evm_verify_hmac(dentry, xattr_name, xattr_value,
66dbc325	157	xattr_value_len, iint);
66dbc325 MZ	158	}
	159	EXPORT_SYMBOL_GPL(evm_verifyxattr);
	160
7102ebcd MZ	161	/*
	162	* evm_verify_current_integrity - verify the dentry's metadata integrity
	163	* @dentry: pointer to the affected dentry
	164	*
	165	* Verify and return the dentry's metadata integrity. The exceptions are
	166	* before EVM is initialized or in 'fix' mode.
	167	*/
	168	static enum integrity_status evm_verify_current_integrity(struct dentry *dentry)
	169	{
	170	struct inode *inode = dentry->d_inode;
	171
	172	if (!evm_initialized \|\| !S_ISREG(inode->i_mode) \|\| evm_fixmode)
	173	return 0;
	174	return evm_verify_hmac(dentry, NULL, NULL, 0, NULL);
	175	}
	176
a924ce0b MZ	177	/*
	178	* evm_protect_xattr - protect the EVM extended attribute
	179	*
bf6d0f5d MZ	180	* Prevent security.evm from being modified or removed without the
	181	* necessary permissions or when the existing value is invalid.
	182	*
	183	* The posix xattr acls are 'system' prefixed, which normally would not
	184	* affect security.evm. An interesting side affect of writing posix xattr
	185	* acls is their modifying of the i_mode, which is included in security.evm.
	186	* For posix xattr acls only, permit security.evm, even if it currently
	187	* doesn't exist, to be updated.
a924ce0b MZ	188	*/
	189	static int evm_protect_xattr(struct dentry dentry, const char xattr_name,
	190	const void *xattr_value, size_t xattr_value_len)
	191	{
	192	enum integrity_status evm_status;
	193
	194	if (strcmp(xattr_name, XATTR_NAME_EVM) == 0) {
	195	if (!capable(CAP_SYS_ADMIN))
	196	return -EPERM;
bf6d0f5d MZ	197	} else if (!evm_protected_xattr(xattr_name)) {
	198	if (!posix_xattr_acl(xattr_name))
	199	return 0;
	200	evm_status = evm_verify_current_integrity(dentry);
	201	if ((evm_status == INTEGRITY_PASS) \|\|
	202	(evm_status == INTEGRITY_NOLABEL))
	203	return 0;
	204	return -EPERM;
	205	}
a924ce0b MZ	206	evm_status = evm_verify_current_integrity(dentry);
	207	return evm_status == INTEGRITY_PASS ? 0 : -EPERM;
	208	}
	209
66dbc325 MZ	210	/**
	211	* evm_inode_setxattr - protect the EVM extended attribute
	212	* @dentry: pointer to the affected dentry
	213	* @xattr_name: pointer to the affected extended attribute name
	214	* @xattr_value: pointer to the new extended attribute value
	215	* @xattr_value_len: pointer to the new extended attribute value length
	216	*
7102ebcd MZ	217	* Updating 'security.evm' requires CAP_SYS_ADMIN privileges and that
7102ebcd MZ	218	* the current value is valid.
66dbc325 MZ	219	*/
	220	int evm_inode_setxattr(struct dentry dentry, const char xattr_name,
	221	const void *xattr_value, size_t xattr_value_len)
	222	{
a924ce0b MZ	223	return evm_protect_xattr(dentry, xattr_name, xattr_value,
a924ce0b MZ	224	xattr_value_len);
66dbc325 MZ	225	}
	226
	227	/**
	228	* evm_inode_removexattr - protect the EVM extended attribute
	229	* @dentry: pointer to the affected dentry
	230	* @xattr_name: pointer to the affected extended attribute name
	231	*
7102ebcd MZ	232	* Removing 'security.evm' requires CAP_SYS_ADMIN privileges and that
7102ebcd MZ	233	* the current value is valid.
66dbc325 MZ	234	*/
	235	int evm_inode_removexattr(struct dentry dentry, const char xattr_name)
	236	{
a924ce0b	237	return evm_protect_xattr(dentry, xattr_name, NULL, 0);
66dbc325 MZ	238	}
	239
	240	/**
	241	* evm_inode_post_setxattr - update 'security.evm' to reflect the changes
	242	* @dentry: pointer to the affected dentry
	243	* @xattr_name: pointer to the affected extended attribute name
	244	* @xattr_value: pointer to the new extended attribute value
	245	* @xattr_value_len: pointer to the new extended attribute value length
	246	*
	247	* Update the HMAC stored in 'security.evm' to reflect the change.
	248	*
	249	* No need to take the i_mutex lock here, as this function is called from
	250	* __vfs_setxattr_noperm(). The caller of which has taken the inode's
	251	* i_mutex lock.
	252	*/
	253	void evm_inode_post_setxattr(struct dentry dentry, const char xattr_name,
	254	const void *xattr_value, size_t xattr_value_len)
	255	{
bf6d0f5d MZ	256	if (!evm_initialized \|\| (!evm_protected_xattr(xattr_name)
bf6d0f5d MZ	257	&& !posix_xattr_acl(xattr_name)))
66dbc325 MZ	258	return;
	259
	260	evm_update_evmxattr(dentry, xattr_name, xattr_value, xattr_value_len);
	261	return;
	262	}
	263
	264	/**
	265	* evm_inode_post_removexattr - update 'security.evm' after removing the xattr
	266	* @dentry: pointer to the affected dentry
	267	* @xattr_name: pointer to the affected extended attribute name
	268	*
	269	* Update the HMAC stored in 'security.evm' to reflect removal of the xattr.
	270	*/
	271	void evm_inode_post_removexattr(struct dentry dentry, const char xattr_name)
	272	{
	273	struct inode *inode = dentry->d_inode;
	274
	275	if (!evm_initialized \|\| !evm_protected_xattr(xattr_name))
	276	return;
	277
	278	mutex_lock(&inode->i_mutex);
	279	evm_update_evmxattr(dentry, xattr_name, NULL, 0);
	280	mutex_unlock(&inode->i_mutex);
	281	return;
	282	}
	283
817b54aa MZ	284	/**
	285	* evm_inode_setattr - prevent updating an invalid EVM extended attribute
	286	* @dentry: pointer to the affected dentry
	287	*/
	288	int evm_inode_setattr(struct dentry dentry, struct iattr attr)
	289	{
	290	unsigned int ia_valid = attr->ia_valid;
	291	enum integrity_status evm_status;
	292
a924ce0b	293	if (!(ia_valid & (ATTR_MODE \| ATTR_UID \| ATTR_GID)))
817b54aa MZ	294	return 0;
	295	evm_status = evm_verify_current_integrity(dentry);
	296	return evm_status == INTEGRITY_PASS ? 0 : -EPERM;
	297	}
	298
66dbc325 MZ	299	/**
	300	* evm_inode_post_setattr - update 'security.evm' after modifying metadata
	301	* @dentry: pointer to the affected dentry
	302	* @ia_valid: for the UID and GID status
	303	*
	304	* For now, update the HMAC stored in 'security.evm' to reflect UID/GID
	305	* changes.
	306	*
	307	* This function is called from notify_change(), which expects the caller
	308	* to lock the inode's i_mutex.
	309	*/
	310	void evm_inode_post_setattr(struct dentry *dentry, int ia_valid)
	311	{
	312	if (!evm_initialized)
	313	return;
	314
	315	if (ia_valid & (ATTR_MODE \| ATTR_UID \| ATTR_GID))
	316	evm_update_evmxattr(dentry, NULL, NULL, 0);
	317	return;
	318	}
	319
cb723180 MZ	320	/*
	321	* evm_inode_init_security - initializes security.evm
	322	*/
	323	int evm_inode_init_security(struct inode *inode,
	324	const struct xattr *lsm_xattr,
	325	struct xattr *evm_xattr)
	326	{
	327	struct evm_ima_xattr_data *xattr_data;
	328	int rc;
	329
	330	if (!evm_initialized \|\| !evm_protected_xattr(lsm_xattr->name))
5a4730ba	331	return 0;
cb723180 MZ	332
	333	xattr_data = kzalloc(sizeof(*xattr_data), GFP_NOFS);
	334	if (!xattr_data)
	335	return -ENOMEM;
	336
	337	xattr_data->type = EVM_XATTR_HMAC;
	338	rc = evm_init_hmac(inode, lsm_xattr, xattr_data->digest);
	339	if (rc < 0)
	340	goto out;
	341
	342	evm_xattr->value = xattr_data;
	343	evm_xattr->value_len = sizeof(*xattr_data);
	344	evm_xattr->name = kstrdup(XATTR_EVM_SUFFIX, GFP_NOFS);
	345	return 0;
	346	out:
	347	kfree(xattr_data);
	348	return rc;
	349	}
	350	EXPORT_SYMBOL_GPL(evm_inode_init_security);
	351
66dbc325 MZ	352	static int __init init_evm(void)
	353	{
	354	int error;
	355
66dbc325 MZ	356	error = evm_init_secfs();
	357	if (error < 0) {
	358	printk(KERN_INFO "EVM: Error registering secfs\n");
	359	goto err;
	360	}
	361	err:
	362	return error;
	363	}
	364
	365	static void __exit cleanup_evm(void)
	366	{
	367	evm_cleanup_secfs();
d46eb369 DK	368	if (hmac_tfm)
d46eb369 DK	369	crypto_free_shash(hmac_tfm);
66dbc325 MZ	370	}
	371
	372	/*
	373	* evm_display_config - list the EVM protected security extended attributes
	374	*/
	375	static int __init evm_display_config(void)
	376	{
	377	char **xattrname;
	378
	379	for (xattrname = evm_config_xattrnames; *xattrname != NULL; xattrname++)
	380	printk(KERN_INFO "EVM: %s\n", *xattrname);
	381	return 0;
	382	}
	383
	384	pure_initcall(evm_display_config);
	385	late_initcall(init_evm);
	386
	387	MODULE_DESCRIPTION("Extended Verification Module");
	388	MODULE_LICENSE("GPL");