xref: /openbmc/linux/security/integrity/ima/ima_appraise.c (revision 39f60c1ccee72caa0104145b5dbf5d37cce1ea39)
1b886d83cSThomas Gleixner // SPDX-License-Identifier: GPL-2.0-only
22fe5d6deSMimi Zohar /*
32fe5d6deSMimi Zohar  * Copyright (C) 2011 IBM Corporation
42fe5d6deSMimi Zohar  *
52fe5d6deSMimi Zohar  * Author:
62fe5d6deSMimi Zohar  * Mimi Zohar <zohar@us.ibm.com>
72fe5d6deSMimi Zohar  */
8b000d5cbSArd Biesheuvel #include <linux/module.h>
9876979c9SPaul Gortmaker #include <linux/init.h>
102fe5d6deSMimi Zohar #include <linux/file.h>
112fe5d6deSMimi Zohar #include <linux/fs.h>
122fe5d6deSMimi Zohar #include <linux/xattr.h>
132fe5d6deSMimi Zohar #include <linux/magic.h>
142fe5d6deSMimi Zohar #include <linux/ima.h>
152fe5d6deSMimi Zohar #include <linux/evm.h>
16398c42e2SMimi Zohar #include <linux/fsverity.h>
17273df864SNayna Jain #include <keys/system_keyring.h>
18398c42e2SMimi Zohar #include <uapi/linux/fsverity.h>
192fe5d6deSMimi Zohar 
202fe5d6deSMimi Zohar #include "ima.h"
212fe5d6deSMimi Zohar 
22e1f5e01fSMimi Zohar #ifdef CONFIG_IMA_APPRAISE_BOOTPARAM
23b000d5cbSArd Biesheuvel static char *ima_appraise_cmdline_default __initdata;
24b000d5cbSArd Biesheuvel core_param(ima_appraise, ima_appraise_cmdline_default, charp, 0);
25b000d5cbSArd Biesheuvel 
26b000d5cbSArd Biesheuvel void __init ima_appraise_parse_cmdline(void)
27b000d5cbSArd Biesheuvel {
28b000d5cbSArd Biesheuvel 	const char *str = ima_appraise_cmdline_default;
29e4d7e2dfSBruno Meneguele 	bool sb_state = arch_ima_get_secureboot();
30e4d7e2dfSBruno Meneguele 	int appraisal_state = ima_appraise;
31311aa6aaSBruno Meneguele 
32b000d5cbSArd Biesheuvel 	if (!str)
33b000d5cbSArd Biesheuvel 		return;
34b000d5cbSArd Biesheuvel 
352fe5d6deSMimi Zohar 	if (strncmp(str, "off", 3) == 0)
36e4d7e2dfSBruno Meneguele 		appraisal_state = 0;
372faa6ef3SDmitry Kasatkin 	else if (strncmp(str, "log", 3) == 0)
38e4d7e2dfSBruno Meneguele 		appraisal_state = IMA_APPRAISE_LOG;
392fe5d6deSMimi Zohar 	else if (strncmp(str, "fix", 3) == 0)
40e4d7e2dfSBruno Meneguele 		appraisal_state = IMA_APPRAISE_FIX;
414afb28abSBruno Meneguele 	else if (strncmp(str, "enforce", 7) == 0)
42e4d7e2dfSBruno Meneguele 		appraisal_state = IMA_APPRAISE_ENFORCE;
437fe2bb7eSBruno Meneguele 	else
447fe2bb7eSBruno Meneguele 		pr_err("invalid \"%s\" appraise option", str);
45e4d7e2dfSBruno Meneguele 
46e4d7e2dfSBruno Meneguele 	/* If appraisal state was changed, but secure boot is enabled,
47e4d7e2dfSBruno Meneguele 	 * keep its default */
48e4d7e2dfSBruno Meneguele 	if (sb_state) {
49e4d7e2dfSBruno Meneguele 		if (!(appraisal_state & IMA_APPRAISE_ENFORCE))
50e4d7e2dfSBruno Meneguele 			pr_info("Secure boot enabled: ignoring ima_appraise=%s option",
51e4d7e2dfSBruno Meneguele 				str);
52e4d7e2dfSBruno Meneguele 	} else {
53e4d7e2dfSBruno Meneguele 		ima_appraise = appraisal_state;
54e4d7e2dfSBruno Meneguele 	}
552fe5d6deSMimi Zohar }
56b000d5cbSArd Biesheuvel #endif
572fe5d6deSMimi Zohar 
582fe5d6deSMimi Zohar /*
596f6723e2SMimi Zohar  * is_ima_appraise_enabled - return appraise status
606f6723e2SMimi Zohar  *
616f6723e2SMimi Zohar  * Only return enabled, if not in ima_appraise="fix" or "log" modes.
626f6723e2SMimi Zohar  */
636f6723e2SMimi Zohar bool is_ima_appraise_enabled(void)
646f6723e2SMimi Zohar {
65e5729f86SThiago Jung Bauermann 	return ima_appraise & IMA_APPRAISE_ENFORCE;
666f6723e2SMimi Zohar }
676f6723e2SMimi Zohar 
686f6723e2SMimi Zohar /*
692fe5d6deSMimi Zohar  * ima_must_appraise - set appraise flag
702fe5d6deSMimi Zohar  *
71da1b0029SMimi Zohar  * Return 1 to appraise or hash
722fe5d6deSMimi Zohar  */
73*39f60c1cSChristian Brauner int ima_must_appraise(struct mnt_idmap *idmap, struct inode *inode,
74a2d2329eSChristian Brauner 		      int mask, enum ima_hooks func)
752fe5d6deSMimi Zohar {
76d906c10dSMatthew Garrett 	u32 secid;
77d906c10dSMatthew Garrett 
7807f6a794SMimi Zohar 	if (!ima_appraise)
792fe5d6deSMimi Zohar 		return 0;
8007f6a794SMimi Zohar 
816326948fSPaul Moore 	security_current_getsecid_subj(&secid);
82*39f60c1cSChristian Brauner 	return ima_match_policy(idmap, inode, current_cred(), secid,
831624dc00STHOBY Simon 				func, mask, IMA_APPRAISE | IMA_HASH, NULL,
841624dc00STHOBY Simon 				NULL, NULL, NULL);
852fe5d6deSMimi Zohar }
862fe5d6deSMimi Zohar 
87def3e8b9SDmitry Kasatkin static int ima_fix_xattr(struct dentry *dentry,
882fe5d6deSMimi Zohar 			 struct integrity_iint_cache *iint)
892fe5d6deSMimi Zohar {
903ea7a560SDmitry Kasatkin 	int rc, offset;
913ea7a560SDmitry Kasatkin 	u8 algo = iint->ima_hash->algo;
923ea7a560SDmitry Kasatkin 
933ea7a560SDmitry Kasatkin 	if (algo <= HASH_ALGO_SHA1) {
943ea7a560SDmitry Kasatkin 		offset = 1;
953ea7a560SDmitry Kasatkin 		iint->ima_hash->xattr.sha1.type = IMA_XATTR_DIGEST;
963ea7a560SDmitry Kasatkin 	} else {
973ea7a560SDmitry Kasatkin 		offset = 0;
983ea7a560SDmitry Kasatkin 		iint->ima_hash->xattr.ng.type = IMA_XATTR_DIGEST_NG;
993ea7a560SDmitry Kasatkin 		iint->ima_hash->xattr.ng.algo = algo;
1003ea7a560SDmitry Kasatkin 	}
101*39f60c1cSChristian Brauner 	rc = __vfs_setxattr_noperm(&nop_mnt_idmap, dentry, XATTR_NAME_IMA,
1023ea7a560SDmitry Kasatkin 				   &iint->ima_hash->xattr.data[offset],
1033ea7a560SDmitry Kasatkin 				   (sizeof(iint->ima_hash->xattr) - offset) +
1043ea7a560SDmitry Kasatkin 				   iint->ima_hash->length, 0);
1053ea7a560SDmitry Kasatkin 	return rc;
1062fe5d6deSMimi Zohar }
1072fe5d6deSMimi Zohar 
108d79d72e0SMimi Zohar /* Return specific func appraised cached result */
109d79d72e0SMimi Zohar enum integrity_status ima_get_cache_status(struct integrity_iint_cache *iint,
1104ad87a3dSMimi Zohar 					   enum ima_hooks func)
111d79d72e0SMimi Zohar {
112d79d72e0SMimi Zohar 	switch (func) {
113d79d72e0SMimi Zohar 	case MMAP_CHECK:
114d79d72e0SMimi Zohar 		return iint->ima_mmap_status;
115d79d72e0SMimi Zohar 	case BPRM_CHECK:
116d79d72e0SMimi Zohar 		return iint->ima_bprm_status;
117d906c10dSMatthew Garrett 	case CREDS_CHECK:
118d906c10dSMatthew Garrett 		return iint->ima_creds_status;
119d79d72e0SMimi Zohar 	case FILE_CHECK:
120c6af8efeSMimi Zohar 	case POST_SETATTR:
121d79d72e0SMimi Zohar 		return iint->ima_file_status;
122c6af8efeSMimi Zohar 	case MODULE_CHECK ... MAX_CHECK - 1:
123c6af8efeSMimi Zohar 	default:
124c6af8efeSMimi Zohar 		return iint->ima_read_status;
125d79d72e0SMimi Zohar 	}
126d79d72e0SMimi Zohar }
127d79d72e0SMimi Zohar 
128d79d72e0SMimi Zohar static void ima_set_cache_status(struct integrity_iint_cache *iint,
1294ad87a3dSMimi Zohar 				 enum ima_hooks func,
1304ad87a3dSMimi Zohar 				 enum integrity_status status)
131d79d72e0SMimi Zohar {
132d79d72e0SMimi Zohar 	switch (func) {
133d79d72e0SMimi Zohar 	case MMAP_CHECK:
134d79d72e0SMimi Zohar 		iint->ima_mmap_status = status;
135d79d72e0SMimi Zohar 		break;
136d79d72e0SMimi Zohar 	case BPRM_CHECK:
137d79d72e0SMimi Zohar 		iint->ima_bprm_status = status;
138d79d72e0SMimi Zohar 		break;
139d906c10dSMatthew Garrett 	case CREDS_CHECK:
140d906c10dSMatthew Garrett 		iint->ima_creds_status = status;
14109186e50SGustavo A. R. Silva 		break;
142d79d72e0SMimi Zohar 	case FILE_CHECK:
143c6af8efeSMimi Zohar 	case POST_SETATTR:
144d79d72e0SMimi Zohar 		iint->ima_file_status = status;
145c6af8efeSMimi Zohar 		break;
146c6af8efeSMimi Zohar 	case MODULE_CHECK ... MAX_CHECK - 1:
147c6af8efeSMimi Zohar 	default:
148c6af8efeSMimi Zohar 		iint->ima_read_status = status;
149c6af8efeSMimi Zohar 		break;
150d79d72e0SMimi Zohar 	}
151d79d72e0SMimi Zohar }
152d79d72e0SMimi Zohar 
1534ad87a3dSMimi Zohar static void ima_cache_flags(struct integrity_iint_cache *iint,
1544ad87a3dSMimi Zohar 			     enum ima_hooks func)
155d79d72e0SMimi Zohar {
156d79d72e0SMimi Zohar 	switch (func) {
157d79d72e0SMimi Zohar 	case MMAP_CHECK:
158d79d72e0SMimi Zohar 		iint->flags |= (IMA_MMAP_APPRAISED | IMA_APPRAISED);
159d79d72e0SMimi Zohar 		break;
160d79d72e0SMimi Zohar 	case BPRM_CHECK:
161d79d72e0SMimi Zohar 		iint->flags |= (IMA_BPRM_APPRAISED | IMA_APPRAISED);
162d79d72e0SMimi Zohar 		break;
163d906c10dSMatthew Garrett 	case CREDS_CHECK:
164d906c10dSMatthew Garrett 		iint->flags |= (IMA_CREDS_APPRAISED | IMA_APPRAISED);
165d906c10dSMatthew Garrett 		break;
166d79d72e0SMimi Zohar 	case FILE_CHECK:
167c6af8efeSMimi Zohar 	case POST_SETATTR:
168d79d72e0SMimi Zohar 		iint->flags |= (IMA_FILE_APPRAISED | IMA_APPRAISED);
169c6af8efeSMimi Zohar 		break;
170c6af8efeSMimi Zohar 	case MODULE_CHECK ... MAX_CHECK - 1:
171c6af8efeSMimi Zohar 	default:
172c6af8efeSMimi Zohar 		iint->flags |= (IMA_READ_APPRAISED | IMA_APPRAISED);
173c6af8efeSMimi Zohar 		break;
174d79d72e0SMimi Zohar 	}
175d79d72e0SMimi Zohar }
176d79d72e0SMimi Zohar 
17750f742ddSTHOBY Simon enum hash_algo ima_get_hash_algo(const struct evm_ima_xattr_data *xattr_value,
1781525b06dSDmitry Kasatkin 				 int xattr_len)
179d3634d0fSDmitry Kasatkin {
180d3634d0fSDmitry Kasatkin 	struct signature_v2_hdr *sig;
181b4bfec7fSSeth Forshee 	enum hash_algo ret;
182d3634d0fSDmitry Kasatkin 
1833ea7a560SDmitry Kasatkin 	if (!xattr_value || xattr_len < 2)
1841525b06dSDmitry Kasatkin 		/* return default hash algo */
1851525b06dSDmitry Kasatkin 		return ima_hash_algo;
186d3634d0fSDmitry Kasatkin 
1873ea7a560SDmitry Kasatkin 	switch (xattr_value->type) {
188398c42e2SMimi Zohar 	case IMA_VERITY_DIGSIG:
189398c42e2SMimi Zohar 		sig = (typeof(sig))xattr_value;
190398c42e2SMimi Zohar 		if (sig->version != 3 || xattr_len <= sizeof(*sig) ||
191398c42e2SMimi Zohar 		    sig->hash_algo >= HASH_ALGO__LAST)
192398c42e2SMimi Zohar 			return ima_hash_algo;
193398c42e2SMimi Zohar 		return sig->hash_algo;
1943ea7a560SDmitry Kasatkin 	case EVM_IMA_XATTR_DIGSIG:
1953ea7a560SDmitry Kasatkin 		sig = (typeof(sig))xattr_value;
196cb181da1STHOBY Simon 		if (sig->version != 2 || xattr_len <= sizeof(*sig)
197cb181da1STHOBY Simon 		    || sig->hash_algo >= HASH_ALGO__LAST)
1981525b06dSDmitry Kasatkin 			return ima_hash_algo;
1991525b06dSDmitry Kasatkin 		return sig->hash_algo;
2003ea7a560SDmitry Kasatkin 	case IMA_XATTR_DIGEST_NG:
201650b29dbSThiago Jung Bauermann 		/* first byte contains algorithm id */
202650b29dbSThiago Jung Bauermann 		ret = xattr_value->data[0];
203b4bfec7fSSeth Forshee 		if (ret < HASH_ALGO__LAST)
204b4bfec7fSSeth Forshee 			return ret;
2053ea7a560SDmitry Kasatkin 		break;
2063ea7a560SDmitry Kasatkin 	case IMA_XATTR_DIGEST:
2073ea7a560SDmitry Kasatkin 		/* this is for backward compatibility */
2083ea7a560SDmitry Kasatkin 		if (xattr_len == 21) {
2093ea7a560SDmitry Kasatkin 			unsigned int zero = 0;
210650b29dbSThiago Jung Bauermann 			if (!memcmp(&xattr_value->data[16], &zero, 4))
2111525b06dSDmitry Kasatkin 				return HASH_ALGO_MD5;
2123ea7a560SDmitry Kasatkin 			else
2131525b06dSDmitry Kasatkin 				return HASH_ALGO_SHA1;
2143ea7a560SDmitry Kasatkin 		} else if (xattr_len == 17)
2151525b06dSDmitry Kasatkin 			return HASH_ALGO_MD5;
2163ea7a560SDmitry Kasatkin 		break;
2173ea7a560SDmitry Kasatkin 	}
2181525b06dSDmitry Kasatkin 
2191525b06dSDmitry Kasatkin 	/* return default hash algo */
2201525b06dSDmitry Kasatkin 	return ima_hash_algo;
221d3634d0fSDmitry Kasatkin }
222d3634d0fSDmitry Kasatkin 
223d3634d0fSDmitry Kasatkin int ima_read_xattr(struct dentry *dentry,
224f6fbd8cbSPaul Moore 		   struct evm_ima_xattr_data **xattr_value, int xattr_len)
225d3634d0fSDmitry Kasatkin {
226f6fbd8cbSPaul Moore 	int ret;
227d3634d0fSDmitry Kasatkin 
2284609e1f1SChristian Brauner 	ret = vfs_getxattr_alloc(&nop_mnt_idmap, dentry, XATTR_NAME_IMA,
229f6fbd8cbSPaul Moore 				 (char **)xattr_value, xattr_len, GFP_NOFS);
2305d6c3191SAndreas Gruenbacher 	if (ret == -EOPNOTSUPP)
2315d6c3191SAndreas Gruenbacher 		ret = 0;
2325d6c3191SAndreas Gruenbacher 	return ret;
233d3634d0fSDmitry Kasatkin }
234d3634d0fSDmitry Kasatkin 
2352fe5d6deSMimi Zohar /*
236398c42e2SMimi Zohar  * calc_file_id_hash - calculate the hash of the ima_file_id struct data
237398c42e2SMimi Zohar  * @type: xattr type [enum evm_ima_xattr_type]
238398c42e2SMimi Zohar  * @algo: hash algorithm [enum hash_algo]
239398c42e2SMimi Zohar  * @digest: pointer to the digest to be hashed
240398c42e2SMimi Zohar  * @hash: (out) pointer to the hash
241398c42e2SMimi Zohar  *
242398c42e2SMimi Zohar  * IMA signature version 3 disambiguates the data that is signed by
243398c42e2SMimi Zohar  * indirectly signing the hash of the ima_file_id structure data.
244398c42e2SMimi Zohar  *
245398c42e2SMimi Zohar  * Signing the ima_file_id struct is currently only supported for
246398c42e2SMimi Zohar  * IMA_VERITY_DIGSIG type xattrs.
247398c42e2SMimi Zohar  *
248398c42e2SMimi Zohar  * Return 0 on success, error code otherwise.
249398c42e2SMimi Zohar  */
250398c42e2SMimi Zohar static int calc_file_id_hash(enum evm_ima_xattr_type type,
251398c42e2SMimi Zohar 			     enum hash_algo algo, const u8 *digest,
252398c42e2SMimi Zohar 			     struct ima_digest_data *hash)
253398c42e2SMimi Zohar {
254398c42e2SMimi Zohar 	struct ima_file_id file_id = {
255398c42e2SMimi Zohar 		.hash_type = IMA_VERITY_DIGSIG, .hash_algorithm = algo};
256398c42e2SMimi Zohar 	unsigned int unused = HASH_MAX_DIGESTSIZE - hash_digest_size[algo];
257398c42e2SMimi Zohar 
258398c42e2SMimi Zohar 	if (type != IMA_VERITY_DIGSIG)
259398c42e2SMimi Zohar 		return -EINVAL;
260398c42e2SMimi Zohar 
261398c42e2SMimi Zohar 	memcpy(file_id.hash, digest, hash_digest_size[algo]);
262398c42e2SMimi Zohar 
263398c42e2SMimi Zohar 	hash->algo = algo;
264398c42e2SMimi Zohar 	hash->length = hash_digest_size[algo];
265398c42e2SMimi Zohar 
266398c42e2SMimi Zohar 	return ima_calc_buffer_hash(&file_id, sizeof(file_id) - unused, hash);
267398c42e2SMimi Zohar }
268398c42e2SMimi Zohar 
269398c42e2SMimi Zohar /*
270a5fbeb61SThiago Jung Bauermann  * xattr_verify - verify xattr digest or signature
271a5fbeb61SThiago Jung Bauermann  *
272a5fbeb61SThiago Jung Bauermann  * Verify whether the hash or signature matches the file contents.
273a5fbeb61SThiago Jung Bauermann  *
274a5fbeb61SThiago Jung Bauermann  * Return 0 on success, error code otherwise.
275a5fbeb61SThiago Jung Bauermann  */
276a5fbeb61SThiago Jung Bauermann static int xattr_verify(enum ima_hooks func, struct integrity_iint_cache *iint,
277a5fbeb61SThiago Jung Bauermann 			struct evm_ima_xattr_data *xattr_value, int xattr_len,
278a5fbeb61SThiago Jung Bauermann 			enum integrity_status *status, const char **cause)
279a5fbeb61SThiago Jung Bauermann {
280398c42e2SMimi Zohar 	struct ima_max_digest_data hash;
281398c42e2SMimi Zohar 	struct signature_v2_hdr *sig;
282a5fbeb61SThiago Jung Bauermann 	int rc = -EINVAL, hash_start = 0;
283398c42e2SMimi Zohar 	int mask;
284a5fbeb61SThiago Jung Bauermann 
285a5fbeb61SThiago Jung Bauermann 	switch (xattr_value->type) {
286a5fbeb61SThiago Jung Bauermann 	case IMA_XATTR_DIGEST_NG:
287a5fbeb61SThiago Jung Bauermann 		/* first byte contains algorithm id */
288a5fbeb61SThiago Jung Bauermann 		hash_start = 1;
289df561f66SGustavo A. R. Silva 		fallthrough;
290a5fbeb61SThiago Jung Bauermann 	case IMA_XATTR_DIGEST:
2917aa5783dSRoberto Sassu 		if (*status != INTEGRITY_PASS_IMMUTABLE) {
292a5fbeb61SThiago Jung Bauermann 			if (iint->flags & IMA_DIGSIG_REQUIRED) {
293398c42e2SMimi Zohar 				if (iint->flags & IMA_VERITY_REQUIRED)
294398c42e2SMimi Zohar 					*cause = "verity-signature-required";
295398c42e2SMimi Zohar 				else
296a5fbeb61SThiago Jung Bauermann 					*cause = "IMA-signature-required";
297a5fbeb61SThiago Jung Bauermann 				*status = INTEGRITY_FAIL;
298a5fbeb61SThiago Jung Bauermann 				break;
299a5fbeb61SThiago Jung Bauermann 			}
300a5fbeb61SThiago Jung Bauermann 			clear_bit(IMA_DIGSIG, &iint->atomic_flags);
3017aa5783dSRoberto Sassu 		} else {
3027aa5783dSRoberto Sassu 			set_bit(IMA_DIGSIG, &iint->atomic_flags);
3037aa5783dSRoberto Sassu 		}
304a5fbeb61SThiago Jung Bauermann 		if (xattr_len - sizeof(xattr_value->type) - hash_start >=
305a5fbeb61SThiago Jung Bauermann 				iint->ima_hash->length)
306a5fbeb61SThiago Jung Bauermann 			/*
307a5fbeb61SThiago Jung Bauermann 			 * xattr length may be longer. md5 hash in previous
308a5fbeb61SThiago Jung Bauermann 			 * version occupied 20 bytes in xattr, instead of 16
309a5fbeb61SThiago Jung Bauermann 			 */
310a5fbeb61SThiago Jung Bauermann 			rc = memcmp(&xattr_value->data[hash_start],
311a5fbeb61SThiago Jung Bauermann 				    iint->ima_hash->digest,
312a5fbeb61SThiago Jung Bauermann 				    iint->ima_hash->length);
313a5fbeb61SThiago Jung Bauermann 		else
314a5fbeb61SThiago Jung Bauermann 			rc = -EINVAL;
315a5fbeb61SThiago Jung Bauermann 		if (rc) {
316a5fbeb61SThiago Jung Bauermann 			*cause = "invalid-hash";
317a5fbeb61SThiago Jung Bauermann 			*status = INTEGRITY_FAIL;
318a5fbeb61SThiago Jung Bauermann 			break;
319a5fbeb61SThiago Jung Bauermann 		}
320a5fbeb61SThiago Jung Bauermann 		*status = INTEGRITY_PASS;
321a5fbeb61SThiago Jung Bauermann 		break;
322a5fbeb61SThiago Jung Bauermann 	case EVM_IMA_XATTR_DIGSIG:
323a5fbeb61SThiago Jung Bauermann 		set_bit(IMA_DIGSIG, &iint->atomic_flags);
324398c42e2SMimi Zohar 
325398c42e2SMimi Zohar 		mask = IMA_DIGSIG_REQUIRED | IMA_VERITY_REQUIRED;
326398c42e2SMimi Zohar 		if ((iint->flags & mask) == mask) {
327398c42e2SMimi Zohar 			*cause = "verity-signature-required";
328398c42e2SMimi Zohar 			*status = INTEGRITY_FAIL;
329398c42e2SMimi Zohar 			break;
330398c42e2SMimi Zohar 		}
331398c42e2SMimi Zohar 
332398c42e2SMimi Zohar 		sig = (typeof(sig))xattr_value;
333398c42e2SMimi Zohar 		if (sig->version >= 3) {
334398c42e2SMimi Zohar 			*cause = "invalid-signature-version";
335398c42e2SMimi Zohar 			*status = INTEGRITY_FAIL;
336398c42e2SMimi Zohar 			break;
337398c42e2SMimi Zohar 		}
338a5fbeb61SThiago Jung Bauermann 		rc = integrity_digsig_verify(INTEGRITY_KEYRING_IMA,
339a5fbeb61SThiago Jung Bauermann 					     (const char *)xattr_value,
340a5fbeb61SThiago Jung Bauermann 					     xattr_len,
341a5fbeb61SThiago Jung Bauermann 					     iint->ima_hash->digest,
342a5fbeb61SThiago Jung Bauermann 					     iint->ima_hash->length);
343a5fbeb61SThiago Jung Bauermann 		if (rc == -EOPNOTSUPP) {
344a5fbeb61SThiago Jung Bauermann 			*status = INTEGRITY_UNKNOWN;
345a5fbeb61SThiago Jung Bauermann 			break;
346a5fbeb61SThiago Jung Bauermann 		}
347a5fbeb61SThiago Jung Bauermann 		if (IS_ENABLED(CONFIG_INTEGRITY_PLATFORM_KEYRING) && rc &&
348a5fbeb61SThiago Jung Bauermann 		    func == KEXEC_KERNEL_CHECK)
349a5fbeb61SThiago Jung Bauermann 			rc = integrity_digsig_verify(INTEGRITY_KEYRING_PLATFORM,
350a5fbeb61SThiago Jung Bauermann 						     (const char *)xattr_value,
351a5fbeb61SThiago Jung Bauermann 						     xattr_len,
352a5fbeb61SThiago Jung Bauermann 						     iint->ima_hash->digest,
353a5fbeb61SThiago Jung Bauermann 						     iint->ima_hash->length);
354a5fbeb61SThiago Jung Bauermann 		if (rc) {
355a5fbeb61SThiago Jung Bauermann 			*cause = "invalid-signature";
356a5fbeb61SThiago Jung Bauermann 			*status = INTEGRITY_FAIL;
357a5fbeb61SThiago Jung Bauermann 		} else {
358a5fbeb61SThiago Jung Bauermann 			*status = INTEGRITY_PASS;
359a5fbeb61SThiago Jung Bauermann 		}
360a5fbeb61SThiago Jung Bauermann 		break;
361398c42e2SMimi Zohar 	case IMA_VERITY_DIGSIG:
362398c42e2SMimi Zohar 		set_bit(IMA_DIGSIG, &iint->atomic_flags);
363398c42e2SMimi Zohar 
364398c42e2SMimi Zohar 		if (iint->flags & IMA_DIGSIG_REQUIRED) {
365398c42e2SMimi Zohar 			if (!(iint->flags & IMA_VERITY_REQUIRED)) {
366398c42e2SMimi Zohar 				*cause = "IMA-signature-required";
367398c42e2SMimi Zohar 				*status = INTEGRITY_FAIL;
368398c42e2SMimi Zohar 				break;
369398c42e2SMimi Zohar 			}
370398c42e2SMimi Zohar 		}
371398c42e2SMimi Zohar 
372398c42e2SMimi Zohar 		sig = (typeof(sig))xattr_value;
373398c42e2SMimi Zohar 		if (sig->version != 3) {
374398c42e2SMimi Zohar 			*cause = "invalid-signature-version";
375398c42e2SMimi Zohar 			*status = INTEGRITY_FAIL;
376398c42e2SMimi Zohar 			break;
377398c42e2SMimi Zohar 		}
378398c42e2SMimi Zohar 
379398c42e2SMimi Zohar 		rc = calc_file_id_hash(IMA_VERITY_DIGSIG, iint->ima_hash->algo,
380398c42e2SMimi Zohar 				       iint->ima_hash->digest, &hash.hdr);
381398c42e2SMimi Zohar 		if (rc) {
382398c42e2SMimi Zohar 			*cause = "sigv3-hashing-error";
383398c42e2SMimi Zohar 			*status = INTEGRITY_FAIL;
384398c42e2SMimi Zohar 			break;
385398c42e2SMimi Zohar 		}
386398c42e2SMimi Zohar 
387398c42e2SMimi Zohar 		rc = integrity_digsig_verify(INTEGRITY_KEYRING_IMA,
388398c42e2SMimi Zohar 					     (const char *)xattr_value,
389398c42e2SMimi Zohar 					     xattr_len, hash.digest,
390398c42e2SMimi Zohar 					     hash.hdr.length);
391398c42e2SMimi Zohar 		if (rc) {
392398c42e2SMimi Zohar 			*cause = "invalid-verity-signature";
393398c42e2SMimi Zohar 			*status = INTEGRITY_FAIL;
394398c42e2SMimi Zohar 		} else {
395398c42e2SMimi Zohar 			*status = INTEGRITY_PASS;
396398c42e2SMimi Zohar 		}
397398c42e2SMimi Zohar 
398398c42e2SMimi Zohar 		break;
399a5fbeb61SThiago Jung Bauermann 	default:
400a5fbeb61SThiago Jung Bauermann 		*status = INTEGRITY_UNKNOWN;
401a5fbeb61SThiago Jung Bauermann 		*cause = "unknown-ima-data";
402a5fbeb61SThiago Jung Bauermann 		break;
403a5fbeb61SThiago Jung Bauermann 	}
404a5fbeb61SThiago Jung Bauermann 
405a5fbeb61SThiago Jung Bauermann 	return rc;
406a5fbeb61SThiago Jung Bauermann }
407a5fbeb61SThiago Jung Bauermann 
408a5fbeb61SThiago Jung Bauermann /*
40939b07096SThiago Jung Bauermann  * modsig_verify - verify modsig signature
41039b07096SThiago Jung Bauermann  *
41139b07096SThiago Jung Bauermann  * Verify whether the signature matches the file contents.
41239b07096SThiago Jung Bauermann  *
41339b07096SThiago Jung Bauermann  * Return 0 on success, error code otherwise.
41439b07096SThiago Jung Bauermann  */
41539b07096SThiago Jung Bauermann static int modsig_verify(enum ima_hooks func, const struct modsig *modsig,
41639b07096SThiago Jung Bauermann 			 enum integrity_status *status, const char **cause)
41739b07096SThiago Jung Bauermann {
41839b07096SThiago Jung Bauermann 	int rc;
41939b07096SThiago Jung Bauermann 
42039b07096SThiago Jung Bauermann 	rc = integrity_modsig_verify(INTEGRITY_KEYRING_IMA, modsig);
42139b07096SThiago Jung Bauermann 	if (IS_ENABLED(CONFIG_INTEGRITY_PLATFORM_KEYRING) && rc &&
42239b07096SThiago Jung Bauermann 	    func == KEXEC_KERNEL_CHECK)
42339b07096SThiago Jung Bauermann 		rc = integrity_modsig_verify(INTEGRITY_KEYRING_PLATFORM,
42439b07096SThiago Jung Bauermann 					     modsig);
42539b07096SThiago Jung Bauermann 	if (rc) {
42639b07096SThiago Jung Bauermann 		*cause = "invalid-signature";
42739b07096SThiago Jung Bauermann 		*status = INTEGRITY_FAIL;
42839b07096SThiago Jung Bauermann 	} else {
42939b07096SThiago Jung Bauermann 		*status = INTEGRITY_PASS;
43039b07096SThiago Jung Bauermann 	}
43139b07096SThiago Jung Bauermann 
43239b07096SThiago Jung Bauermann 	return rc;
43339b07096SThiago Jung Bauermann }
43439b07096SThiago Jung Bauermann 
43539b07096SThiago Jung Bauermann /*
436273df864SNayna Jain  * ima_check_blacklist - determine if the binary is blacklisted.
437273df864SNayna Jain  *
438273df864SNayna Jain  * Add the hash of the blacklisted binary to the measurement list, based
439273df864SNayna Jain  * on policy.
440273df864SNayna Jain  *
441273df864SNayna Jain  * Returns -EPERM if the hash is blacklisted.
442273df864SNayna Jain  */
443273df864SNayna Jain int ima_check_blacklist(struct integrity_iint_cache *iint,
444273df864SNayna Jain 			const struct modsig *modsig, int pcr)
445273df864SNayna Jain {
446273df864SNayna Jain 	enum hash_algo hash_algo;
447273df864SNayna Jain 	const u8 *digest = NULL;
448273df864SNayna Jain 	u32 digestsize = 0;
449273df864SNayna Jain 	int rc = 0;
450273df864SNayna Jain 
451273df864SNayna Jain 	if (!(iint->flags & IMA_CHECK_BLACKLIST))
452273df864SNayna Jain 		return 0;
453273df864SNayna Jain 
454273df864SNayna Jain 	if (iint->flags & IMA_MODSIG_ALLOWED && modsig) {
455273df864SNayna Jain 		ima_get_modsig_digest(modsig, &hash_algo, &digest, &digestsize);
456273df864SNayna Jain 
457273df864SNayna Jain 		rc = is_binary_blacklisted(digest, digestsize);
458273df864SNayna Jain 		if ((rc == -EPERM) && (iint->flags & IMA_MEASURE))
459*39f60c1cSChristian Brauner 			process_buffer_measurement(&nop_mnt_idmap, NULL, digest, digestsize,
460273df864SNayna Jain 						   "blacklisted-hash", NONE,
461ca3c9bdbSRoberto Sassu 						   pcr, NULL, false, NULL, 0);
462273df864SNayna Jain 	}
463273df864SNayna Jain 
464273df864SNayna Jain 	return rc;
465273df864SNayna Jain }
466273df864SNayna Jain 
467273df864SNayna Jain /*
4682fe5d6deSMimi Zohar  * ima_appraise_measurement - appraise file measurement
4692fe5d6deSMimi Zohar  *
4702fe5d6deSMimi Zohar  * Call evm_verifyxattr() to verify the integrity of 'security.ima'.
4712fe5d6deSMimi Zohar  * Assuming success, compare the xattr hash with the collected measurement.
4722fe5d6deSMimi Zohar  *
4732fe5d6deSMimi Zohar  * Return 0 on success, error code otherwise
4742fe5d6deSMimi Zohar  */
4754ad87a3dSMimi Zohar int ima_appraise_measurement(enum ima_hooks func,
4764ad87a3dSMimi Zohar 			     struct integrity_iint_cache *iint,
477d3634d0fSDmitry Kasatkin 			     struct file *file, const unsigned char *filename,
478d3634d0fSDmitry Kasatkin 			     struct evm_ima_xattr_data *xattr_value,
47939b07096SThiago Jung Bauermann 			     int xattr_len, const struct modsig *modsig)
4802fe5d6deSMimi Zohar {
48152a13284SMimi Zohar 	static const char op[] = "appraise_data";
482f5e51fa3SThiago Jung Bauermann 	const char *cause = "unknown";
483e71b9dffSMiklos Szeredi 	struct dentry *dentry = file_dentry(file);
484c6f493d6SDavid Howells 	struct inode *inode = d_backing_inode(dentry);
4852fe5d6deSMimi Zohar 	enum integrity_status status = INTEGRITY_UNKNOWN;
486a5fbeb61SThiago Jung Bauermann 	int rc = xattr_len;
48739b07096SThiago Jung Bauermann 	bool try_modsig = iint->flags & IMA_MODSIG_ALLOWED && modsig;
4882fe5d6deSMimi Zohar 
48939b07096SThiago Jung Bauermann 	/* If not appraising a modsig, we need an xattr. */
49039b07096SThiago Jung Bauermann 	if (!(inode->i_opflags & IOP_XATTR) && !try_modsig)
4912fe5d6deSMimi Zohar 		return INTEGRITY_UNKNOWN;
4922fe5d6deSMimi Zohar 
49339b07096SThiago Jung Bauermann 	/* If reading the xattr failed and there's no modsig, error out. */
49439b07096SThiago Jung Bauermann 	if (rc <= 0 && !try_modsig) {
4952fe5d6deSMimi Zohar 		if (rc && rc != -ENODATA)
4962fe5d6deSMimi Zohar 			goto out;
4972fe5d6deSMimi Zohar 
498398c42e2SMimi Zohar 		if (iint->flags & IMA_DIGSIG_REQUIRED) {
499398c42e2SMimi Zohar 			if (iint->flags & IMA_VERITY_REQUIRED)
500398c42e2SMimi Zohar 				cause = "verity-signature-required";
501398c42e2SMimi Zohar 			else
502398c42e2SMimi Zohar 				cause = "IMA-signature-required";
503398c42e2SMimi Zohar 		} else {
504398c42e2SMimi Zohar 			cause = "missing-hash";
505398c42e2SMimi Zohar 		}
506398c42e2SMimi Zohar 
507b151d6b0SDmitry Kasatkin 		status = INTEGRITY_NOLABEL;
5086035a27bSAl Viro 		if (file->f_mode & FMODE_CREATED)
509b151d6b0SDmitry Kasatkin 			iint->flags |= IMA_NEW_FILE;
5101ac202e9SDaniel Glöckner 		if ((iint->flags & IMA_NEW_FILE) &&
511b7e27bc1SMimi Zohar 		    (!(iint->flags & IMA_DIGSIG_REQUIRED) ||
512b7e27bc1SMimi Zohar 		     (inode->i_size == 0)))
513b151d6b0SDmitry Kasatkin 			status = INTEGRITY_PASS;
5142fe5d6deSMimi Zohar 		goto out;
5152fe5d6deSMimi Zohar 	}
5162fe5d6deSMimi Zohar 
517d2ee2cfcSHuaxin Lu 	status = evm_verifyxattr(dentry, XATTR_NAME_IMA, xattr_value,
518d2ee2cfcSHuaxin Lu 				 rc < 0 ? 0 : rc, iint);
519f5e51fa3SThiago Jung Bauermann 	switch (status) {
520f5e51fa3SThiago Jung Bauermann 	case INTEGRITY_PASS:
521f5e51fa3SThiago Jung Bauermann 	case INTEGRITY_PASS_IMMUTABLE:
522f5e51fa3SThiago Jung Bauermann 	case INTEGRITY_UNKNOWN:
523f5e51fa3SThiago Jung Bauermann 		break;
524f5e51fa3SThiago Jung Bauermann 	case INTEGRITY_NOXATTRS:	/* No EVM protected xattrs. */
52539b07096SThiago Jung Bauermann 		/* It's fine not to have xattrs when using a modsig. */
52639b07096SThiago Jung Bauermann 		if (try_modsig)
52739b07096SThiago Jung Bauermann 			break;
528df561f66SGustavo A. R. Silva 		fallthrough;
529f5e51fa3SThiago Jung Bauermann 	case INTEGRITY_NOLABEL:		/* No security.evm xattr. */
5302fe5d6deSMimi Zohar 		cause = "missing-HMAC";
531f5e51fa3SThiago Jung Bauermann 		goto out;
532cdef685bSRoberto Sassu 	case INTEGRITY_FAIL_IMMUTABLE:
5337aa5783dSRoberto Sassu 		set_bit(IMA_DIGSIG, &iint->atomic_flags);
53455748ac6SMimi Zohar 		cause = "invalid-fail-immutable";
53555748ac6SMimi Zohar 		goto out;
536f5e51fa3SThiago Jung Bauermann 	case INTEGRITY_FAIL:		/* Invalid HMAC/signature. */
5372fe5d6deSMimi Zohar 		cause = "invalid-HMAC";
5382fe5d6deSMimi Zohar 		goto out;
539f5e51fa3SThiago Jung Bauermann 	default:
540f5e51fa3SThiago Jung Bauermann 		WARN_ONCE(true, "Unexpected integrity status %d\n", status);
5412fe5d6deSMimi Zohar 	}
542f5e51fa3SThiago Jung Bauermann 
543a5fbeb61SThiago Jung Bauermann 	if (xattr_value)
544a5fbeb61SThiago Jung Bauermann 		rc = xattr_verify(func, iint, xattr_value, xattr_len, &status,
545a5fbeb61SThiago Jung Bauermann 				  &cause);
5468606404fSDmitry Kasatkin 
54739b07096SThiago Jung Bauermann 	/*
54839b07096SThiago Jung Bauermann 	 * If we have a modsig and either no imasig or the imasig's key isn't
54939b07096SThiago Jung Bauermann 	 * known, then try verifying the modsig.
55039b07096SThiago Jung Bauermann 	 */
55139b07096SThiago Jung Bauermann 	if (try_modsig &&
55239b07096SThiago Jung Bauermann 	    (!xattr_value || xattr_value->type == IMA_XATTR_DIGEST_NG ||
55339b07096SThiago Jung Bauermann 	     rc == -ENOKEY))
55439b07096SThiago Jung Bauermann 		rc = modsig_verify(func, modsig, &status, &cause);
55539b07096SThiago Jung Bauermann 
5562fe5d6deSMimi Zohar out:
55757b56ac6SMimi Zohar 	/*
55857b56ac6SMimi Zohar 	 * File signatures on some filesystems can not be properly verified.
5599e67028eSMimi Zohar 	 * When such filesystems are mounted by an untrusted mounter or on a
5609e67028eSMimi Zohar 	 * system not willing to accept such a risk, fail the file signature
5619e67028eSMimi Zohar 	 * verification.
56257b56ac6SMimi Zohar 	 */
5639e67028eSMimi Zohar 	if ((inode->i_sb->s_iflags & SB_I_IMA_UNVERIFIABLE_SIGNATURE) &&
5649e67028eSMimi Zohar 	    ((inode->i_sb->s_iflags & SB_I_UNTRUSTED_MOUNTER) ||
5659e67028eSMimi Zohar 	     (iint->flags & IMA_FAIL_UNVERIFIABLE_SIGS))) {
56657b56ac6SMimi Zohar 		status = INTEGRITY_FAIL;
56757b56ac6SMimi Zohar 		cause = "unverifiable-signature";
56857b56ac6SMimi Zohar 		integrity_audit_msg(AUDIT_INTEGRITY_DATA, inode, filename,
56957b56ac6SMimi Zohar 				    op, cause, rc, 0);
57057b56ac6SMimi Zohar 	} else if (status != INTEGRITY_PASS) {
571f5e51fa3SThiago Jung Bauermann 		/* Fix mode, but don't replace file signatures. */
57239b07096SThiago Jung Bauermann 		if ((ima_appraise & IMA_APPRAISE_FIX) && !try_modsig &&
5738606404fSDmitry Kasatkin 		    (!xattr_value ||
5748606404fSDmitry Kasatkin 		     xattr_value->type != EVM_IMA_XATTR_DIGSIG)) {
575def3e8b9SDmitry Kasatkin 			if (!ima_fix_xattr(dentry, iint))
5762fe5d6deSMimi Zohar 				status = INTEGRITY_PASS;
577f5e51fa3SThiago Jung Bauermann 		}
578f5e51fa3SThiago Jung Bauermann 
5797aa5783dSRoberto Sassu 		/*
5807aa5783dSRoberto Sassu 		 * Permit new files with file/EVM portable signatures, but
5817aa5783dSRoberto Sassu 		 * without data.
5827aa5783dSRoberto Sassu 		 */
583f5e51fa3SThiago Jung Bauermann 		if (inode->i_size == 0 && iint->flags & IMA_NEW_FILE &&
5847aa5783dSRoberto Sassu 		    test_bit(IMA_DIGSIG, &iint->atomic_flags)) {
58505d1a717SMimi Zohar 			status = INTEGRITY_PASS;
5862fe5d6deSMimi Zohar 		}
587f5e51fa3SThiago Jung Bauermann 
5882fe5d6deSMimi Zohar 		integrity_audit_msg(AUDIT_INTEGRITY_DATA, inode, filename,
5892fe5d6deSMimi Zohar 				    op, cause, rc, 0);
5908606404fSDmitry Kasatkin 	} else {
591d79d72e0SMimi Zohar 		ima_cache_flags(iint, func);
5922fe5d6deSMimi Zohar 	}
59357b56ac6SMimi Zohar 
594d79d72e0SMimi Zohar 	ima_set_cache_status(iint, func, status);
5952fe5d6deSMimi Zohar 	return status;
5962fe5d6deSMimi Zohar }
5972fe5d6deSMimi Zohar 
5982fe5d6deSMimi Zohar /*
5992fe5d6deSMimi Zohar  * ima_update_xattr - update 'security.ima' hash value
6002fe5d6deSMimi Zohar  */
6012fe5d6deSMimi Zohar void ima_update_xattr(struct integrity_iint_cache *iint, struct file *file)
6022fe5d6deSMimi Zohar {
603e71b9dffSMiklos Szeredi 	struct dentry *dentry = file_dentry(file);
6042fe5d6deSMimi Zohar 	int rc = 0;
6052fe5d6deSMimi Zohar 
6068606404fSDmitry Kasatkin 	/* do not collect and update hash for digital signatures */
6070d73a552SDmitry Kasatkin 	if (test_bit(IMA_DIGSIG, &iint->atomic_flags))
6088606404fSDmitry Kasatkin 		return;
6098606404fSDmitry Kasatkin 
610da1b0029SMimi Zohar 	if ((iint->ima_file_status != INTEGRITY_PASS) &&
611da1b0029SMimi Zohar 	    !(iint->flags & IMA_HASH))
612020aae3eSRoberto Sassu 		return;
613020aae3eSRoberto Sassu 
61415588227SThiago Jung Bauermann 	rc = ima_collect_measurement(iint, file, NULL, 0, ima_hash_algo, NULL);
6152fe5d6deSMimi Zohar 	if (rc < 0)
6162fe5d6deSMimi Zohar 		return;
6178606404fSDmitry Kasatkin 
6180d73a552SDmitry Kasatkin 	inode_lock(file_inode(file));
6192fe5d6deSMimi Zohar 	ima_fix_xattr(dentry, iint);
6200d73a552SDmitry Kasatkin 	inode_unlock(file_inode(file));
6212fe5d6deSMimi Zohar }
6222fe5d6deSMimi Zohar 
6232fe5d6deSMimi Zohar /**
6242fe5d6deSMimi Zohar  * ima_inode_post_setattr - reflect file metadata changes
625*39f60c1cSChristian Brauner  * @idmap:  idmap of the mount the inode was found from
6262fe5d6deSMimi Zohar  * @dentry: pointer to the affected dentry
6272fe5d6deSMimi Zohar  *
6282fe5d6deSMimi Zohar  * Changes to a dentry's metadata might result in needing to appraise.
6292fe5d6deSMimi Zohar  *
6302fe5d6deSMimi Zohar  * This function is called from notify_change(), which expects the caller
6312fe5d6deSMimi Zohar  * to lock the inode's i_mutex.
6322fe5d6deSMimi Zohar  */
633*39f60c1cSChristian Brauner void ima_inode_post_setattr(struct mnt_idmap *idmap,
634a2d2329eSChristian Brauner 			    struct dentry *dentry)
6352fe5d6deSMimi Zohar {
636c6f493d6SDavid Howells 	struct inode *inode = d_backing_inode(dentry);
6372fe5d6deSMimi Zohar 	struct integrity_iint_cache *iint;
638da1b0029SMimi Zohar 	int action;
6392fe5d6deSMimi Zohar 
640a756024eSRoberto Sassu 	if (!(ima_policy_flag & IMA_APPRAISE) || !S_ISREG(inode->i_mode)
6415d6c3191SAndreas Gruenbacher 	    || !(inode->i_opflags & IOP_XATTR))
6422fe5d6deSMimi Zohar 		return;
6432fe5d6deSMimi Zohar 
644*39f60c1cSChristian Brauner 	action = ima_must_appraise(idmap, inode, MAY_ACCESS, POST_SETATTR);
6450d73a552SDmitry Kasatkin 	iint = integrity_iint_find(inode);
6460d73a552SDmitry Kasatkin 	if (iint) {
6470d73a552SDmitry Kasatkin 		set_bit(IMA_CHANGE_ATTR, &iint->atomic_flags);
648da1b0029SMimi Zohar 		if (!action)
6490d73a552SDmitry Kasatkin 			clear_bit(IMA_UPDATE_XATTR, &iint->atomic_flags);
6500d73a552SDmitry Kasatkin 	}
6512fe5d6deSMimi Zohar }
65242c63330SMimi Zohar 
65342c63330SMimi Zohar /*
65442c63330SMimi Zohar  * ima_protect_xattr - protect 'security.ima'
65542c63330SMimi Zohar  *
65642c63330SMimi Zohar  * Ensure that not just anyone can modify or remove 'security.ima'.
65742c63330SMimi Zohar  */
65842c63330SMimi Zohar static int ima_protect_xattr(struct dentry *dentry, const char *xattr_name,
65942c63330SMimi Zohar 			     const void *xattr_value, size_t xattr_value_len)
66042c63330SMimi Zohar {
66142c63330SMimi Zohar 	if (strcmp(xattr_name, XATTR_NAME_IMA) == 0) {
66242c63330SMimi Zohar 		if (!capable(CAP_SYS_ADMIN))
66342c63330SMimi Zohar 			return -EPERM;
66442c63330SMimi Zohar 		return 1;
66542c63330SMimi Zohar 	}
66642c63330SMimi Zohar 	return 0;
66742c63330SMimi Zohar }
66842c63330SMimi Zohar 
669060bdebfSMimi Zohar static void ima_reset_appraise_flags(struct inode *inode, int digsig)
67042c63330SMimi Zohar {
67142c63330SMimi Zohar 	struct integrity_iint_cache *iint;
67242c63330SMimi Zohar 
673a756024eSRoberto Sassu 	if (!(ima_policy_flag & IMA_APPRAISE) || !S_ISREG(inode->i_mode))
67442c63330SMimi Zohar 		return;
67542c63330SMimi Zohar 
67642c63330SMimi Zohar 	iint = integrity_iint_find(inode);
67742c63330SMimi Zohar 	if (!iint)
67842c63330SMimi Zohar 		return;
679a422638dSEric Richter 	iint->measured_pcrs = 0;
6800d73a552SDmitry Kasatkin 	set_bit(IMA_CHANGE_XATTR, &iint->atomic_flags);
681060bdebfSMimi Zohar 	if (digsig)
6820d73a552SDmitry Kasatkin 		set_bit(IMA_DIGSIG, &iint->atomic_flags);
6830d73a552SDmitry Kasatkin 	else
6840d73a552SDmitry Kasatkin 		clear_bit(IMA_DIGSIG, &iint->atomic_flags);
68542c63330SMimi Zohar }
68642c63330SMimi Zohar 
68750f742ddSTHOBY Simon /**
68850f742ddSTHOBY Simon  * validate_hash_algo() - Block setxattr with unsupported hash algorithms
68950f742ddSTHOBY Simon  * @dentry: object of the setxattr()
69050f742ddSTHOBY Simon  * @xattr_value: userland supplied xattr value
69150f742ddSTHOBY Simon  * @xattr_value_len: length of xattr_value
69250f742ddSTHOBY Simon  *
69350f742ddSTHOBY Simon  * The xattr value is mapped to its hash algorithm, and this algorithm
69450f742ddSTHOBY Simon  * must be built in the kernel for the setxattr to be allowed.
69550f742ddSTHOBY Simon  *
69650f742ddSTHOBY Simon  * Emit an audit message when the algorithm is invalid.
69750f742ddSTHOBY Simon  *
69850f742ddSTHOBY Simon  * Return: 0 on success, else an error.
69950f742ddSTHOBY Simon  */
70050f742ddSTHOBY Simon static int validate_hash_algo(struct dentry *dentry,
70150f742ddSTHOBY Simon 			      const struct evm_ima_xattr_data *xattr_value,
70250f742ddSTHOBY Simon 			      size_t xattr_value_len)
70350f742ddSTHOBY Simon {
70450f742ddSTHOBY Simon 	char *path = NULL, *pathbuf = NULL;
70550f742ddSTHOBY Simon 	enum hash_algo xattr_hash_algo;
7064f2946aaSTHOBY Simon 	const char *errmsg = "unavailable-hash-algorithm";
7074f2946aaSTHOBY Simon 	unsigned int allowed_hashes;
70850f742ddSTHOBY Simon 
70950f742ddSTHOBY Simon 	xattr_hash_algo = ima_get_hash_algo(xattr_value, xattr_value_len);
71050f742ddSTHOBY Simon 
7114f2946aaSTHOBY Simon 	allowed_hashes = atomic_read(&ima_setxattr_allowed_hash_algorithms);
7124f2946aaSTHOBY Simon 
7134f2946aaSTHOBY Simon 	if (allowed_hashes) {
7144f2946aaSTHOBY Simon 		/* success if the algorithm is allowed in the ima policy */
7154f2946aaSTHOBY Simon 		if (allowed_hashes & (1U << xattr_hash_algo))
71650f742ddSTHOBY Simon 			return 0;
71750f742ddSTHOBY Simon 
7184f2946aaSTHOBY Simon 		/*
7194f2946aaSTHOBY Simon 		 * We use a different audit message when the hash algorithm
7204f2946aaSTHOBY Simon 		 * is denied by a policy rule, instead of not being built
7214f2946aaSTHOBY Simon 		 * in the kernel image
7224f2946aaSTHOBY Simon 		 */
7234f2946aaSTHOBY Simon 		errmsg = "denied-hash-algorithm";
7244f2946aaSTHOBY Simon 	} else {
7254f2946aaSTHOBY Simon 		if (likely(xattr_hash_algo == ima_hash_algo))
7264f2946aaSTHOBY Simon 			return 0;
7274f2946aaSTHOBY Simon 
7284f2946aaSTHOBY Simon 		/* allow any xattr using an algorithm built in the kernel */
7294f2946aaSTHOBY Simon 		if (crypto_has_alg(hash_algo_name[xattr_hash_algo], 0, 0))
7304f2946aaSTHOBY Simon 			return 0;
7314f2946aaSTHOBY Simon 	}
7324f2946aaSTHOBY Simon 
73350f742ddSTHOBY Simon 	pathbuf = kmalloc(PATH_MAX, GFP_KERNEL);
73450f742ddSTHOBY Simon 	if (!pathbuf)
73550f742ddSTHOBY Simon 		return -EACCES;
73650f742ddSTHOBY Simon 
73750f742ddSTHOBY Simon 	path = dentry_path(dentry, pathbuf, PATH_MAX);
73850f742ddSTHOBY Simon 
73950f742ddSTHOBY Simon 	integrity_audit_msg(AUDIT_INTEGRITY_DATA, d_inode(dentry), path,
7404f2946aaSTHOBY Simon 			    "set_data", errmsg, -EACCES, 0);
74150f742ddSTHOBY Simon 
74250f742ddSTHOBY Simon 	kfree(pathbuf);
74350f742ddSTHOBY Simon 
74450f742ddSTHOBY Simon 	return -EACCES;
74550f742ddSTHOBY Simon }
74650f742ddSTHOBY Simon 
74742c63330SMimi Zohar int ima_inode_setxattr(struct dentry *dentry, const char *xattr_name,
74842c63330SMimi Zohar 		       const void *xattr_value, size_t xattr_value_len)
74942c63330SMimi Zohar {
750060bdebfSMimi Zohar 	const struct evm_ima_xattr_data *xvalue = xattr_value;
751e3ccfe1aSRoberto Sassu 	int digsig = 0;
75242c63330SMimi Zohar 	int result;
7535926586fSMimi Zohar 	int err;
75442c63330SMimi Zohar 
75542c63330SMimi Zohar 	result = ima_protect_xattr(dentry, xattr_name, xattr_value,
75642c63330SMimi Zohar 				   xattr_value_len);
75742c63330SMimi Zohar 	if (result == 1) {
758a48fda9dSDmitry Kasatkin 		if (!xattr_value_len || (xvalue->type >= IMA_XATTR_LAST))
759a48fda9dSDmitry Kasatkin 			return -EINVAL;
7605926586fSMimi Zohar 
7615926586fSMimi Zohar 		err = validate_hash_algo(dentry, xvalue, xattr_value_len);
7625926586fSMimi Zohar 		if (err)
7635926586fSMimi Zohar 			return err;
7645926586fSMimi Zohar 
765e3ccfe1aSRoberto Sassu 		digsig = (xvalue->type == EVM_IMA_XATTR_DIGSIG);
7667aa5783dSRoberto Sassu 	} else if (!strcmp(xattr_name, XATTR_NAME_EVM) && xattr_value_len > 0) {
7677aa5783dSRoberto Sassu 		digsig = (xvalue->type == EVM_XATTR_PORTABLE_DIGSIG);
768e3ccfe1aSRoberto Sassu 	}
769e3ccfe1aSRoberto Sassu 	if (result == 1 || evm_revalidate_status(xattr_name)) {
770e3ccfe1aSRoberto Sassu 		ima_reset_appraise_flags(d_backing_inode(dentry), digsig);
7715926586fSMimi Zohar 		if (result == 1)
7725926586fSMimi Zohar 			result = 0;
77342c63330SMimi Zohar 	}
77442c63330SMimi Zohar 	return result;
77542c63330SMimi Zohar }
77642c63330SMimi Zohar 
777e61b135fSChristian Brauner int ima_inode_set_acl(struct user_namespace *mnt_userns, struct dentry *dentry,
778e61b135fSChristian Brauner 		      const char *acl_name, struct posix_acl *kacl)
779e61b135fSChristian Brauner {
780e61b135fSChristian Brauner 	if (evm_revalidate_status(acl_name))
781e61b135fSChristian Brauner 		ima_reset_appraise_flags(d_backing_inode(dentry), 0);
782e61b135fSChristian Brauner 
783e61b135fSChristian Brauner 	return 0;
784e61b135fSChristian Brauner }
785e61b135fSChristian Brauner 
78642c63330SMimi Zohar int ima_inode_removexattr(struct dentry *dentry, const char *xattr_name)
78742c63330SMimi Zohar {
78842c63330SMimi Zohar 	int result;
78942c63330SMimi Zohar 
79042c63330SMimi Zohar 	result = ima_protect_xattr(dentry, xattr_name, NULL, 0);
791e3ccfe1aSRoberto Sassu 	if (result == 1 || evm_revalidate_status(xattr_name)) {
792c6f493d6SDavid Howells 		ima_reset_appraise_flags(d_backing_inode(dentry), 0);
793e3ccfe1aSRoberto Sassu 		if (result == 1)
79442c63330SMimi Zohar 			result = 0;
79542c63330SMimi Zohar 	}
79642c63330SMimi Zohar 	return result;
79742c63330SMimi Zohar }
798