[deliverable/linux.git] / security / integrity / ima / ima_appraise.c

/*
 * Copyright (C) 2011 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.
 */
#include <linux/module.h>
#include <linux/file.h>
#include <linux/fs.h>
#include <linux/xattr.h>
#include <linux/magic.h>
#include <linux/ima.h>
#include <linux/evm.h>
#include <crypto/hash_info.h>

#include "ima.h"

static int __init default_appraise_setup(char *str)
{
	if (strncmp(str, "off", 3) == 0)
		ima_appraise = 0;
	else if (strncmp(str, "fix", 3) == 0)
		ima_appraise = IMA_APPRAISE_FIX;
	return 1;
}

__setup("ima_appraise=", default_appraise_setup);

/*
 * ima_must_appraise - set appraise flag
 *
 * Return 1 to appraise
 */
int ima_must_appraise(struct inode *inode, int mask, enum ima_hooks func)
{
	if (!ima_appraise)
		return 0;

	return ima_match_policy(inode, func, mask, IMA_APPRAISE);
}

static int ima_fix_xattr(struct dentry *dentry,
			 struct integrity_iint_cache *iint)
{
	int rc, offset;
	u8 algo = iint->ima_hash->algo;

	if (algo <= HASH_ALGO_SHA1) {
		offset = 1;
		iint->ima_hash->xattr.sha1.type = IMA_XATTR_DIGEST;
	} else {
		offset = 0;
		iint->ima_hash->xattr.ng.type = IMA_XATTR_DIGEST_NG;
		iint->ima_hash->xattr.ng.algo = algo;
	}
	rc = __vfs_setxattr_noperm(dentry, XATTR_NAME_IMA,
				   &iint->ima_hash->xattr.data[offset],
				   (sizeof(iint->ima_hash->xattr) - offset) +
				   iint->ima_hash->length, 0);
	return rc;
}

/* Return specific func appraised cached result */
enum integrity_status ima_get_cache_status(struct integrity_iint_cache *iint,
					   int func)
{
	switch (func) {
	case MMAP_CHECK:
		return iint->ima_mmap_status;
	case BPRM_CHECK:
		return iint->ima_bprm_status;
	case MODULE_CHECK:
		return iint->ima_module_status;
	case FIRMWARE_CHECK:
		return iint->ima_firmware_status;
	case FILE_CHECK:
	default:
		return iint->ima_file_status;
	}
}

static void ima_set_cache_status(struct integrity_iint_cache *iint,
				 int func, enum integrity_status status)
{
	switch (func) {
	case MMAP_CHECK:
		iint->ima_mmap_status = status;
		break;
	case BPRM_CHECK:
		iint->ima_bprm_status = status;
		break;
	case MODULE_CHECK:
		iint->ima_module_status = status;
		break;
	case FIRMWARE_CHECK:
		iint->ima_firmware_status = status;
		break;
	case FILE_CHECK:
	default:
		iint->ima_file_status = status;
		break;
	}
}

static void ima_cache_flags(struct integrity_iint_cache *iint, int func)
{
	switch (func) {
	case MMAP_CHECK:
		iint->flags |= (IMA_MMAP_APPRAISED | IMA_APPRAISED);
		break;
	case BPRM_CHECK:
		iint->flags |= (IMA_BPRM_APPRAISED | IMA_APPRAISED);
		break;
	case MODULE_CHECK:
		iint->flags |= (IMA_MODULE_APPRAISED | IMA_APPRAISED);
		break;
	case FIRMWARE_CHECK:
		iint->flags |= (IMA_FIRMWARE_APPRAISED | IMA_APPRAISED);
		break;
	case FILE_CHECK:
	default:
		iint->flags |= (IMA_FILE_APPRAISED | IMA_APPRAISED);
		break;
	}
}

void ima_get_hash_algo(struct evm_ima_xattr_data *xattr_value, int xattr_len,
		       struct ima_digest_data *hash)
{
	struct signature_v2_hdr *sig;

	if (!xattr_value || xattr_len < 2)
		return;

	switch (xattr_value->type) {
	case EVM_IMA_XATTR_DIGSIG:
		sig = (typeof(sig))xattr_value;
		if (sig->version != 2 || xattr_len <= sizeof(*sig))
			return;
		hash->algo = sig->hash_algo;
		break;
	case IMA_XATTR_DIGEST_NG:
		hash->algo = xattr_value->digest[0];
		break;
	case IMA_XATTR_DIGEST:
		/* this is for backward compatibility */
		if (xattr_len == 21) {
			unsigned int zero = 0;
			if (!memcmp(&xattr_value->digest[16], &zero, 4))
				hash->algo = HASH_ALGO_MD5;
			else
				hash->algo = HASH_ALGO_SHA1;
		} else if (xattr_len == 17)
			hash->algo = HASH_ALGO_MD5;
		break;
	}
}

int ima_read_xattr(struct dentry *dentry,
		   struct evm_ima_xattr_data **xattr_value)
{
	struct inode *inode = dentry->d_inode;

	if (!inode->i_op->getxattr)
		return 0;

	return vfs_getxattr_alloc(dentry, XATTR_NAME_IMA, (char **)xattr_value,
				  0, GFP_NOFS);
}

/*
 * ima_appraise_measurement - appraise file measurement
 *
 * Call evm_verifyxattr() to verify the integrity of 'security.ima'.
 * Assuming success, compare the xattr hash with the collected measurement.
 *
 * Return 0 on success, error code otherwise
 */
int ima_appraise_measurement(int func, struct integrity_iint_cache *iint,
			     struct file *file, const unsigned char *filename,
			     struct evm_ima_xattr_data *xattr_value,
			     int xattr_len)
{
	static const char op[] = "appraise_data";
	char *cause = "unknown";
	struct dentry *dentry = file->f_dentry;
	struct inode *inode = dentry->d_inode;
	enum integrity_status status = INTEGRITY_UNKNOWN;
	int rc = xattr_len, hash_start = 0;

	if (!ima_appraise)
		return 0;
	if (!inode->i_op->getxattr)
		return INTEGRITY_UNKNOWN;

	if (rc <= 0) {
		if (rc && rc != -ENODATA)
			goto out;

		cause = "missing-hash";
		status = INTEGRITY_NOLABEL;
		if (inode->i_size == 0) {
			iint->flags |= IMA_NEW_FILE;
			status = INTEGRITY_PASS;
		}
		goto out;
	}

	status = evm_verifyxattr(dentry, XATTR_NAME_IMA, xattr_value, rc, iint);
	if ((status != INTEGRITY_PASS) && (status != INTEGRITY_UNKNOWN)) {
		if ((status == INTEGRITY_NOLABEL)
		    || (status == INTEGRITY_NOXATTRS))
			cause = "missing-HMAC";
		else if (status == INTEGRITY_FAIL)
			cause = "invalid-HMAC";
		goto out;
	}
	switch (xattr_value->type) {
	case IMA_XATTR_DIGEST_NG:
		/* first byte contains algorithm id */
		hash_start = 1;
	case IMA_XATTR_DIGEST:
		if (iint->flags & IMA_DIGSIG_REQUIRED) {
			cause = "IMA-signature-required";
			status = INTEGRITY_FAIL;
			break;
		}
		if (xattr_len - sizeof(xattr_value->type) - hash_start >=
				iint->ima_hash->length)
			/* xattr length may be longer. md5 hash in previous
			   version occupied 20 bytes in xattr, instead of 16
			 */
			rc = memcmp(&xattr_value->digest[hash_start],
				    iint->ima_hash->digest,
				    iint->ima_hash->length);
		else
			rc = -EINVAL;
		if (rc) {
			cause = "invalid-hash";
			status = INTEGRITY_FAIL;
			break;
		}
		status = INTEGRITY_PASS;
		break;
	case EVM_IMA_XATTR_DIGSIG:
		iint->flags |= IMA_DIGSIG;
		rc = integrity_digsig_verify(INTEGRITY_KEYRING_IMA,
					     (const char *)xattr_value, rc,
					     iint->ima_hash->digest,
					     iint->ima_hash->length);
		if (rc == -EOPNOTSUPP) {
			status = INTEGRITY_UNKNOWN;
		} else if (rc) {
			cause = "invalid-signature";
			status = INTEGRITY_FAIL;
		} else {
			status = INTEGRITY_PASS;
		}
		break;
	default:
		status = INTEGRITY_UNKNOWN;
		cause = "unknown-ima-data";
		break;
	}

out:
	if (status != INTEGRITY_PASS) {
		if ((ima_appraise & IMA_APPRAISE_FIX) &&
		    (!xattr_value ||
		     xattr_value->type != EVM_IMA_XATTR_DIGSIG)) {
			if (!ima_fix_xattr(dentry, iint))
				status = INTEGRITY_PASS;
		}
		integrity_audit_msg(AUDIT_INTEGRITY_DATA, inode, filename,
				    op, cause, rc, 0);
	} else {
		ima_cache_flags(iint, func);
	}
	ima_set_cache_status(iint, func, status);
	return status;
}

/*
 * ima_update_xattr - update 'security.ima' hash value
 */
void ima_update_xattr(struct integrity_iint_cache *iint, struct file *file)
{
	struct dentry *dentry = file->f_dentry;
	int rc = 0;

	/* do not collect and update hash for digital signatures */
	if (iint->flags & IMA_DIGSIG)
		return;

	rc = ima_collect_measurement(iint, file, NULL, NULL);
	if (rc < 0)
		return;

	ima_fix_xattr(dentry, iint);
}

/**
 * ima_inode_post_setattr - reflect file metadata changes
 * @dentry: pointer to the affected dentry
 *
 * Changes to a dentry's metadata might result in needing to appraise.
 *
 * This function is called from notify_change(), which expects the caller
 * to lock the inode's i_mutex.
 */
void ima_inode_post_setattr(struct dentry *dentry)
{
	struct inode *inode = dentry->d_inode;
	struct integrity_iint_cache *iint;
	int must_appraise, rc;

	if (!ima_initialized || !ima_appraise || !S_ISREG(inode->i_mode)
	    || !inode->i_op->removexattr)
		return;

	must_appraise = ima_must_appraise(inode, MAY_ACCESS, POST_SETATTR);
	iint = integrity_iint_find(inode);
	if (iint) {
		iint->flags &= ~(IMA_APPRAISE | IMA_APPRAISED |
				 IMA_APPRAISE_SUBMASK | IMA_APPRAISED_SUBMASK |
				 IMA_ACTION_FLAGS);
		if (must_appraise)
			iint->flags |= IMA_APPRAISE;
	}
	if (!must_appraise)
		rc = inode->i_op->removexattr(dentry, XATTR_NAME_IMA);
	return;
}

/*
 * ima_protect_xattr - protect 'security.ima'
 *
 * Ensure that not just anyone can modify or remove 'security.ima'.
 */
static int ima_protect_xattr(struct dentry *dentry, const char *xattr_name,
			     const void *xattr_value, size_t xattr_value_len)
{
	if (strcmp(xattr_name, XATTR_NAME_IMA) == 0) {
		if (!capable(CAP_SYS_ADMIN))
			return -EPERM;
		return 1;
	}
	return 0;
}

static void ima_reset_appraise_flags(struct inode *inode, int digsig)
{
	struct integrity_iint_cache *iint;

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

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

	iint->flags &= ~IMA_DONE_MASK;
	if (digsig)
		iint->flags |= IMA_DIGSIG;
	return;
}

int ima_inode_setxattr(struct dentry *dentry, const char *xattr_name,
		       const void *xattr_value, size_t xattr_value_len)
{
	const struct evm_ima_xattr_data *xvalue = xattr_value;
	int result;

	result = ima_protect_xattr(dentry, xattr_name, xattr_value,
				   xattr_value_len);
	if (result == 1) {
		ima_reset_appraise_flags(dentry->d_inode,
			 (xvalue->type == EVM_IMA_XATTR_DIGSIG) ? 1 : 0);
		result = 0;
	}
	return result;
}

int ima_inode_removexattr(struct dentry *dentry, const char *xattr_name)
{
	int result;

	result = ima_protect_xattr(dentry, xattr_name, NULL, 0);
	if (result == 1) {
		ima_reset_appraise_flags(dentry->d_inode, 0);
		result = 0;
	}
	return result;
}
Commit	Line	Data
2fe5d6de MZ	1	/*
	2	* Copyright (C) 2011 IBM Corporation
	3	*
	4	* Author:
	5	* Mimi Zohar <zohar@us.ibm.com>
	6	*
	7	* This program is free software; you can redistribute it and/or modify
	8	* it under the terms of the GNU General Public License as published by
	9	* the Free Software Foundation, version 2 of the License.
	10	*/
	11	#include <linux/module.h>
	12	#include <linux/file.h>
	13	#include <linux/fs.h>
	14	#include <linux/xattr.h>
	15	#include <linux/magic.h>
	16	#include <linux/ima.h>
	17	#include <linux/evm.h>
3ea7a560	18	#include <crypto/hash_info.h>
2fe5d6de MZ	19
	20	#include "ima.h"
	21
	22	static int __init default_appraise_setup(char *str)
	23	{
	24	if (strncmp(str, "off", 3) == 0)
	25	ima_appraise = 0;
	26	else if (strncmp(str, "fix", 3) == 0)
	27	ima_appraise = IMA_APPRAISE_FIX;
	28	return 1;
	29	}
	30
	31	__setup("ima_appraise=", default_appraise_setup);
	32
	33	/*
	34	* ima_must_appraise - set appraise flag
	35	*
	36	* Return 1 to appraise
	37	*/
d26e1936	38	int ima_must_appraise(struct inode *inode, int mask, enum ima_hooks func)
2fe5d6de	39	{
07f6a794 MZ	40	if (!ima_appraise)
	41	return 0;
	42
	43	return ima_match_policy(inode, func, mask, IMA_APPRAISE);
2fe5d6de MZ	44	}
2fe5d6de MZ	45
def3e8b9	46	static int ima_fix_xattr(struct dentry *dentry,
c7c8bb23	47	struct integrity_iint_cache *iint)
2fe5d6de	48	{
3ea7a560 DK	49	int rc, offset;
	50	u8 algo = iint->ima_hash->algo;
	51
	52	if (algo <= HASH_ALGO_SHA1) {
	53	offset = 1;
	54	iint->ima_hash->xattr.sha1.type = IMA_XATTR_DIGEST;
	55	} else {
	56	offset = 0;
	57	iint->ima_hash->xattr.ng.type = IMA_XATTR_DIGEST_NG;
	58	iint->ima_hash->xattr.ng.algo = algo;
	59	}
	60	rc = __vfs_setxattr_noperm(dentry, XATTR_NAME_IMA,
	61	&iint->ima_hash->xattr.data[offset],
	62	(sizeof(iint->ima_hash->xattr) - offset) +
	63	iint->ima_hash->length, 0);
	64	return rc;
2fe5d6de MZ	65	}
2fe5d6de MZ	66
d79d72e0 MZ	67	/* Return specific func appraised cached result */
	68	enum integrity_status ima_get_cache_status(struct integrity_iint_cache *iint,
	69	int func)
	70	{
089bc8e9	71	switch (func) {
d79d72e0 MZ	72	case MMAP_CHECK:
	73	return iint->ima_mmap_status;
	74	case BPRM_CHECK:
	75	return iint->ima_bprm_status;
	76	case MODULE_CHECK:
	77	return iint->ima_module_status;
5a9196d7 MZ	78	case FIRMWARE_CHECK:
5a9196d7 MZ	79	return iint->ima_firmware_status;
d79d72e0 MZ	80	case FILE_CHECK:
	81	default:
	82	return iint->ima_file_status;
	83	}
	84	}
	85
	86	static void ima_set_cache_status(struct integrity_iint_cache *iint,
	87	int func, enum integrity_status status)
	88	{
089bc8e9	89	switch (func) {
d79d72e0 MZ	90	case MMAP_CHECK:
	91	iint->ima_mmap_status = status;
	92	break;
	93	case BPRM_CHECK:
	94	iint->ima_bprm_status = status;
	95	break;
	96	case MODULE_CHECK:
	97	iint->ima_module_status = status;
	98	break;
5a9196d7 MZ	99	case FIRMWARE_CHECK:
	100	iint->ima_firmware_status = status;
	101	break;
d79d72e0 MZ	102	case FILE_CHECK:
	103	default:
	104	iint->ima_file_status = status;
	105	break;
	106	}
	107	}
	108
	109	static void ima_cache_flags(struct integrity_iint_cache *iint, int func)
	110	{
089bc8e9	111	switch (func) {
d79d72e0 MZ	112	case MMAP_CHECK:
	113	iint->flags \|= (IMA_MMAP_APPRAISED \| IMA_APPRAISED);
	114	break;
	115	case BPRM_CHECK:
	116	iint->flags \|= (IMA_BPRM_APPRAISED \| IMA_APPRAISED);
	117	break;
	118	case MODULE_CHECK:
	119	iint->flags \|= (IMA_MODULE_APPRAISED \| IMA_APPRAISED);
	120	break;
5a9196d7 MZ	121	case FIRMWARE_CHECK:
	122	iint->flags \|= (IMA_FIRMWARE_APPRAISED \| IMA_APPRAISED);
	123	break;
d79d72e0 MZ	124	case FILE_CHECK:
	125	default:
	126	iint->flags \|= (IMA_FILE_APPRAISED \| IMA_APPRAISED);
	127	break;
	128	}
	129	}
	130
d3634d0f DK	131	void ima_get_hash_algo(struct evm_ima_xattr_data *xattr_value, int xattr_len,
	132	struct ima_digest_data *hash)
	133	{
	134	struct signature_v2_hdr *sig;
	135
3ea7a560	136	if (!xattr_value \|\| xattr_len < 2)
d3634d0f DK	137	return;
d3634d0f DK	138
3ea7a560 DK	139	switch (xattr_value->type) {
	140	case EVM_IMA_XATTR_DIGSIG:
	141	sig = (typeof(sig))xattr_value;
	142	if (sig->version != 2 \|\| xattr_len <= sizeof(*sig))
	143	return;
	144	hash->algo = sig->hash_algo;
	145	break;
	146	case IMA_XATTR_DIGEST_NG:
	147	hash->algo = xattr_value->digest[0];
	148	break;
	149	case IMA_XATTR_DIGEST:
	150	/* this is for backward compatibility */
	151	if (xattr_len == 21) {
	152	unsigned int zero = 0;
	153	if (!memcmp(&xattr_value->digest[16], &zero, 4))
	154	hash->algo = HASH_ALGO_MD5;
	155	else
	156	hash->algo = HASH_ALGO_SHA1;
	157	} else if (xattr_len == 17)
	158	hash->algo = HASH_ALGO_MD5;
	159	break;
	160	}
d3634d0f DK	161	}
	162
	163	int ima_read_xattr(struct dentry *dentry,
	164	struct evm_ima_xattr_data **xattr_value)
	165	{
	166	struct inode *inode = dentry->d_inode;
	167
	168	if (!inode->i_op->getxattr)
	169	return 0;
	170
	171	return vfs_getxattr_alloc(dentry, XATTR_NAME_IMA, (char **)xattr_value,
	172	0, GFP_NOFS);
	173	}
	174
2fe5d6de MZ	175	/*
	176	* ima_appraise_measurement - appraise file measurement
	177	*
	178	* Call evm_verifyxattr() to verify the integrity of 'security.ima'.
	179	* Assuming success, compare the xattr hash with the collected measurement.
	180	*
	181	* Return 0 on success, error code otherwise
	182	*/
d79d72e0	183	int ima_appraise_measurement(int func, struct integrity_iint_cache *iint,
d3634d0f DK	184	struct file file, const unsigned char filename,
	185	struct evm_ima_xattr_data *xattr_value,
	186	int xattr_len)
2fe5d6de	187	{
52a13284 MZ	188	static const char op[] = "appraise_data";
52a13284 MZ	189	char *cause = "unknown";
2fe5d6de MZ	190	struct dentry *dentry = file->f_dentry;
2fe5d6de MZ	191	struct inode *inode = dentry->d_inode;
2fe5d6de	192	enum integrity_status status = INTEGRITY_UNKNOWN;
3ea7a560	193	int rc = xattr_len, hash_start = 0;
2fe5d6de MZ	194
	195	if (!ima_appraise)
	196	return 0;
	197	if (!inode->i_op->getxattr)
	198	return INTEGRITY_UNKNOWN;
	199
2fe5d6de MZ	200	if (rc <= 0) {
	201	if (rc && rc != -ENODATA)
	202	goto out;
	203
	204	cause = "missing-hash";
b151d6b0 DK	205	status = INTEGRITY_NOLABEL;
	206	if (inode->i_size == 0) {
	207	iint->flags \|= IMA_NEW_FILE;
	208	status = INTEGRITY_PASS;
	209	}
2fe5d6de MZ	210	goto out;
	211	}
	212
8606404f	213	status = evm_verifyxattr(dentry, XATTR_NAME_IMA, xattr_value, rc, iint);
2fe5d6de MZ	214	if ((status != INTEGRITY_PASS) && (status != INTEGRITY_UNKNOWN)) {
	215	if ((status == INTEGRITY_NOLABEL)
	216	\|\| (status == INTEGRITY_NOXATTRS))
	217	cause = "missing-HMAC";
	218	else if (status == INTEGRITY_FAIL)
	219	cause = "invalid-HMAC";
	220	goto out;
	221	}
8606404f	222	switch (xattr_value->type) {
3ea7a560 DK	223	case IMA_XATTR_DIGEST_NG:
	224	/* first byte contains algorithm id */
	225	hash_start = 1;
8606404f	226	case IMA_XATTR_DIGEST:
0e5a247c	227	if (iint->flags & IMA_DIGSIG_REQUIRED) {
7e9001f6	228	cause = "IMA-signature-required";
0e5a247c DK	229	status = INTEGRITY_FAIL;
	230	break;
	231	}
3ea7a560 DK	232	if (xattr_len - sizeof(xattr_value->type) - hash_start >=
3ea7a560 DK	233	iint->ima_hash->length)
d3634d0f DK	234	/* xattr length may be longer. md5 hash in previous
	235	version occupied 20 bytes in xattr, instead of 16
	236	*/
3ea7a560	237	rc = memcmp(&xattr_value->digest[hash_start],
a35c3fb6 DK	238	iint->ima_hash->digest,
a35c3fb6 DK	239	iint->ima_hash->length);
c7c8bb23 DK	240	else
c7c8bb23 DK	241	rc = -EINVAL;
8606404f DK	242	if (rc) {
	243	cause = "invalid-hash";
	244	status = INTEGRITY_FAIL;
8606404f DK	245	break;
	246	}
	247	status = INTEGRITY_PASS;
	248	break;
	249	case EVM_IMA_XATTR_DIGSIG:
	250	iint->flags \|= IMA_DIGSIG;
	251	rc = integrity_digsig_verify(INTEGRITY_KEYRING_IMA,
b1aaab22	252	(const char *)xattr_value, rc,
a35c3fb6 DK	253	iint->ima_hash->digest,
a35c3fb6 DK	254	iint->ima_hash->length);
8606404f DK	255	if (rc == -EOPNOTSUPP) {
	256	status = INTEGRITY_UNKNOWN;
	257	} else if (rc) {
	258	cause = "invalid-signature";
	259	status = INTEGRITY_FAIL;
	260	} else {
	261	status = INTEGRITY_PASS;
	262	}
	263	break;
	264	default:
	265	status = INTEGRITY_UNKNOWN;
	266	cause = "unknown-ima-data";
	267	break;
2fe5d6de	268	}
8606404f	269
2fe5d6de MZ	270	out:
2fe5d6de MZ	271	if (status != INTEGRITY_PASS) {
8606404f DK	272	if ((ima_appraise & IMA_APPRAISE_FIX) &&
	273	(!xattr_value \|\|
	274	xattr_value->type != EVM_IMA_XATTR_DIGSIG)) {
def3e8b9 DK	275	if (!ima_fix_xattr(dentry, iint))
def3e8b9 DK	276	status = INTEGRITY_PASS;
2fe5d6de MZ	277	}
	278	integrity_audit_msg(AUDIT_INTEGRITY_DATA, inode, filename,
	279	op, cause, rc, 0);
8606404f	280	} else {
d79d72e0	281	ima_cache_flags(iint, func);
2fe5d6de	282	}
d79d72e0	283	ima_set_cache_status(iint, func, status);
2fe5d6de MZ	284	return status;
	285	}
	286
	287	/*
	288	* ima_update_xattr - update 'security.ima' hash value
	289	*/
	290	void ima_update_xattr(struct integrity_iint_cache iint, struct file file)
	291	{
	292	struct dentry *dentry = file->f_dentry;
	293	int rc = 0;
	294
8606404f DK	295	/* do not collect and update hash for digital signatures */
	296	if (iint->flags & IMA_DIGSIG)
	297	return;
	298
d3634d0f	299	rc = ima_collect_measurement(iint, file, NULL, NULL);
2fe5d6de MZ	300	if (rc < 0)
2fe5d6de MZ	301	return;
8606404f	302
2fe5d6de MZ	303	ima_fix_xattr(dentry, iint);
	304	}
	305
	306	/**
	307	* ima_inode_post_setattr - reflect file metadata changes
	308	* @dentry: pointer to the affected dentry
	309	*
	310	* Changes to a dentry's metadata might result in needing to appraise.
	311	*
	312	* This function is called from notify_change(), which expects the caller
	313	* to lock the inode's i_mutex.
	314	*/
	315	void ima_inode_post_setattr(struct dentry *dentry)
	316	{
	317	struct inode *inode = dentry->d_inode;
	318	struct integrity_iint_cache *iint;
	319	int must_appraise, rc;
	320
	321	if (!ima_initialized \|\| !ima_appraise \|\| !S_ISREG(inode->i_mode)
	322	\|\| !inode->i_op->removexattr)
	323	return;
	324
	325	must_appraise = ima_must_appraise(inode, MAY_ACCESS, POST_SETATTR);
	326	iint = integrity_iint_find(inode);
	327	if (iint) {
d79d72e0 MZ	328	iint->flags &= ~(IMA_APPRAISE \| IMA_APPRAISED \|
	329	IMA_APPRAISE_SUBMASK \| IMA_APPRAISED_SUBMASK \|
	330	IMA_ACTION_FLAGS);
2fe5d6de MZ	331	if (must_appraise)
2fe5d6de MZ	332	iint->flags \|= IMA_APPRAISE;
2fe5d6de MZ	333	}
	334	if (!must_appraise)
	335	rc = inode->i_op->removexattr(dentry, XATTR_NAME_IMA);
	336	return;
	337	}
42c63330 MZ	338
	339	/*
	340	* ima_protect_xattr - protect 'security.ima'
	341	*
	342	* Ensure that not just anyone can modify or remove 'security.ima'.
	343	*/
	344	static int ima_protect_xattr(struct dentry dentry, const char xattr_name,
	345	const void *xattr_value, size_t xattr_value_len)
	346	{
	347	if (strcmp(xattr_name, XATTR_NAME_IMA) == 0) {
	348	if (!capable(CAP_SYS_ADMIN))
	349	return -EPERM;
	350	return 1;
	351	}
	352	return 0;
	353	}
	354
060bdebf	355	static void ima_reset_appraise_flags(struct inode *inode, int digsig)
42c63330 MZ	356	{
	357	struct integrity_iint_cache *iint;
	358
	359	if (!ima_initialized \|\| !ima_appraise \|\| !S_ISREG(inode->i_mode))
	360	return;
	361
	362	iint = integrity_iint_find(inode);
	363	if (!iint)
	364	return;
	365
45e2472e	366	iint->flags &= ~IMA_DONE_MASK;
060bdebf MZ	367	if (digsig)
060bdebf MZ	368	iint->flags \|= IMA_DIGSIG;
42c63330 MZ	369	return;
	370	}
	371
	372	int ima_inode_setxattr(struct dentry dentry, const char xattr_name,
	373	const void *xattr_value, size_t xattr_value_len)
	374	{
060bdebf	375	const struct evm_ima_xattr_data *xvalue = xattr_value;
42c63330 MZ	376	int result;
	377
	378	result = ima_protect_xattr(dentry, xattr_name, xattr_value,
	379	xattr_value_len);
	380	if (result == 1) {
060bdebf MZ	381	ima_reset_appraise_flags(dentry->d_inode,
060bdebf MZ	382	(xvalue->type == EVM_IMA_XATTR_DIGSIG) ? 1 : 0);
42c63330 MZ	383	result = 0;
	384	}
	385	return result;
	386	}
	387
	388	int ima_inode_removexattr(struct dentry dentry, const char xattr_name)
	389	{
	390	int result;
	391
	392	result = ima_protect_xattr(dentry, xattr_name, NULL, 0);
	393	if (result == 1) {
060bdebf	394	ima_reset_appraise_flags(dentry->d_inode, 0);
42c63330 MZ	395	result = 0;
	396	}
	397	return result;
	398	}