Mimi Zohar | 66dbc325 | 2011-03-15 16:12:09 -0400 | [diff] [blame] | 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> |
Mimi Zohar | 9b97b6c | 2013-02-21 09:31:22 -0500 | [diff] [blame] | 19 | #include <linux/audit.h> |
Mimi Zohar | 66dbc325 | 2011-03-15 16:12:09 -0400 | [diff] [blame] | 20 | #include <linux/xattr.h> |
| 21 | #include <linux/integrity.h> |
Mimi Zohar | 3e1be52 | 2011-03-09 14:38:26 -0500 | [diff] [blame] | 22 | #include <linux/evm.h> |
Dmitry Kasatkin | d46eb36 | 2011-03-09 15:07:36 -0500 | [diff] [blame] | 23 | #include <crypto/hash.h> |
Mimi Zohar | 66dbc325 | 2011-03-15 16:12:09 -0400 | [diff] [blame] | 24 | #include "evm.h" |
| 25 | |
| 26 | int evm_initialized; |
| 27 | |
Mimi Zohar | 9b97b6c | 2013-02-21 09:31:22 -0500 | [diff] [blame] | 28 | static char *integrity_status_msg[] = { |
| 29 | "pass", "fail", "no_label", "no_xattrs", "unknown" |
| 30 | }; |
Mimi Zohar | 66dbc325 | 2011-03-15 16:12:09 -0400 | [diff] [blame] | 31 | char *evm_hmac = "hmac(sha1)"; |
Dmitry Kasatkin | 15647eb | 2011-09-01 14:41:40 +0300 | [diff] [blame] | 32 | char *evm_hash = "sha1"; |
Dmitry Kasatkin | 74de668 | 2012-09-10 10:37:20 +0300 | [diff] [blame] | 33 | int evm_hmac_version = CONFIG_EVM_HMAC_VERSION; |
Mimi Zohar | 66dbc325 | 2011-03-15 16:12:09 -0400 | [diff] [blame] | 34 | |
| 35 | char *evm_config_xattrnames[] = { |
| 36 | #ifdef CONFIG_SECURITY_SELINUX |
| 37 | XATTR_NAME_SELINUX, |
| 38 | #endif |
| 39 | #ifdef CONFIG_SECURITY_SMACK |
| 40 | XATTR_NAME_SMACK, |
| 41 | #endif |
Mimi Zohar | 2fe5d6d | 2012-02-13 10:15:05 -0500 | [diff] [blame] | 42 | #ifdef CONFIG_IMA_APPRAISE |
| 43 | XATTR_NAME_IMA, |
| 44 | #endif |
Mimi Zohar | 66dbc325 | 2011-03-15 16:12:09 -0400 | [diff] [blame] | 45 | XATTR_NAME_CAPS, |
| 46 | NULL |
| 47 | }; |
| 48 | |
Mimi Zohar | 7102ebc | 2011-05-12 18:33:20 -0400 | [diff] [blame] | 49 | static int evm_fixmode; |
| 50 | static int __init evm_set_fixmode(char *str) |
| 51 | { |
| 52 | if (strncmp(str, "fix", 3) == 0) |
| 53 | evm_fixmode = 1; |
| 54 | return 0; |
| 55 | } |
| 56 | __setup("evm=", evm_set_fixmode); |
| 57 | |
Dmitry Kasatkin | 15647eb | 2011-09-01 14:41:40 +0300 | [diff] [blame] | 58 | static int evm_find_protected_xattrs(struct dentry *dentry) |
| 59 | { |
| 60 | struct inode *inode = dentry->d_inode; |
| 61 | char **xattr; |
| 62 | int error; |
| 63 | int count = 0; |
| 64 | |
| 65 | if (!inode->i_op || !inode->i_op->getxattr) |
| 66 | return -EOPNOTSUPP; |
| 67 | |
| 68 | for (xattr = evm_config_xattrnames; *xattr != NULL; xattr++) { |
| 69 | error = inode->i_op->getxattr(dentry, *xattr, NULL, 0); |
| 70 | if (error < 0) { |
| 71 | if (error == -ENODATA) |
| 72 | continue; |
| 73 | return error; |
| 74 | } |
| 75 | count++; |
| 76 | } |
| 77 | |
| 78 | return count; |
| 79 | } |
| 80 | |
Mimi Zohar | 66dbc325 | 2011-03-15 16:12:09 -0400 | [diff] [blame] | 81 | /* |
| 82 | * evm_verify_hmac - calculate and compare the HMAC with the EVM xattr |
| 83 | * |
| 84 | * Compute the HMAC on the dentry's protected set of extended attributes |
Mimi Zohar | 7102ebc | 2011-05-12 18:33:20 -0400 | [diff] [blame] | 85 | * and compare it against the stored security.evm xattr. |
| 86 | * |
| 87 | * For performance: |
| 88 | * - use the previoulsy retrieved xattr value and length to calculate the |
| 89 | * HMAC.) |
| 90 | * - cache the verification result in the iint, when available. |
Mimi Zohar | 66dbc325 | 2011-03-15 16:12:09 -0400 | [diff] [blame] | 91 | * |
| 92 | * Returns integrity status |
| 93 | */ |
| 94 | static enum integrity_status evm_verify_hmac(struct dentry *dentry, |
| 95 | const char *xattr_name, |
| 96 | char *xattr_value, |
| 97 | size_t xattr_value_len, |
| 98 | struct integrity_iint_cache *iint) |
| 99 | { |
Dmitry Kasatkin | 15647eb | 2011-09-01 14:41:40 +0300 | [diff] [blame] | 100 | struct evm_ima_xattr_data *xattr_data = NULL; |
| 101 | struct evm_ima_xattr_data calc; |
Mimi Zohar | 566be59 | 2011-08-22 09:14:18 -0400 | [diff] [blame] | 102 | enum integrity_status evm_status = INTEGRITY_PASS; |
Dmitry Kasatkin | 15647eb | 2011-09-01 14:41:40 +0300 | [diff] [blame] | 103 | int rc, xattr_len; |
Mimi Zohar | 66dbc325 | 2011-03-15 16:12:09 -0400 | [diff] [blame] | 104 | |
Mimi Zohar | 7102ebc | 2011-05-12 18:33:20 -0400 | [diff] [blame] | 105 | if (iint && iint->evm_status == INTEGRITY_PASS) |
Dmitry Kasatkin | 24e0198 | 2011-05-06 11:34:17 +0300 | [diff] [blame] | 106 | return iint->evm_status; |
Mimi Zohar | 66dbc325 | 2011-03-15 16:12:09 -0400 | [diff] [blame] | 107 | |
Dmitry Kasatkin | 6d38ca01 | 2011-05-06 11:34:14 +0300 | [diff] [blame] | 108 | /* if status is not PASS, try to check again - against -ENOMEM */ |
| 109 | |
Dmitry Kasatkin | 15647eb | 2011-09-01 14:41:40 +0300 | [diff] [blame] | 110 | /* first need to know the sig type */ |
| 111 | rc = vfs_getxattr_alloc(dentry, XATTR_NAME_EVM, (char **)&xattr_data, 0, |
| 112 | GFP_NOFS); |
| 113 | if (rc <= 0) { |
| 114 | if (rc == 0) |
| 115 | evm_status = INTEGRITY_FAIL; /* empty */ |
| 116 | else if (rc == -ENODATA) { |
| 117 | rc = evm_find_protected_xattrs(dentry); |
| 118 | if (rc > 0) |
| 119 | evm_status = INTEGRITY_NOLABEL; |
| 120 | else if (rc == 0) |
| 121 | evm_status = INTEGRITY_NOXATTRS; /* new file */ |
| 122 | } |
Mimi Zohar | 566be59 | 2011-08-22 09:14:18 -0400 | [diff] [blame] | 123 | goto out; |
| 124 | } |
Mimi Zohar | 66dbc325 | 2011-03-15 16:12:09 -0400 | [diff] [blame] | 125 | |
Dmitry Kasatkin | 15647eb | 2011-09-01 14:41:40 +0300 | [diff] [blame] | 126 | xattr_len = rc - 1; |
| 127 | |
| 128 | /* check value type */ |
| 129 | switch (xattr_data->type) { |
| 130 | case EVM_XATTR_HMAC: |
| 131 | rc = evm_calc_hmac(dentry, xattr_name, xattr_value, |
| 132 | xattr_value_len, calc.digest); |
| 133 | if (rc) |
| 134 | break; |
| 135 | rc = memcmp(xattr_data->digest, calc.digest, |
| 136 | sizeof(calc.digest)); |
| 137 | if (rc) |
| 138 | rc = -EINVAL; |
| 139 | break; |
| 140 | case EVM_IMA_XATTR_DIGSIG: |
| 141 | rc = evm_calc_hash(dentry, xattr_name, xattr_value, |
| 142 | xattr_value_len, calc.digest); |
| 143 | if (rc) |
| 144 | break; |
| 145 | rc = integrity_digsig_verify(INTEGRITY_KEYRING_EVM, |
| 146 | xattr_data->digest, xattr_len, |
| 147 | calc.digest, sizeof(calc.digest)); |
| 148 | if (!rc) { |
| 149 | /* we probably want to replace rsa with hmac here */ |
| 150 | evm_update_evmxattr(dentry, xattr_name, xattr_value, |
| 151 | xattr_value_len); |
| 152 | } |
| 153 | break; |
| 154 | default: |
| 155 | rc = -EINVAL; |
| 156 | break; |
| 157 | } |
| 158 | |
| 159 | if (rc) |
| 160 | evm_status = (rc == -ENODATA) ? |
| 161 | INTEGRITY_NOXATTRS : INTEGRITY_FAIL; |
Mimi Zohar | 7102ebc | 2011-05-12 18:33:20 -0400 | [diff] [blame] | 162 | out: |
| 163 | if (iint) |
| 164 | iint->evm_status = evm_status; |
Dmitry Kasatkin | 15647eb | 2011-09-01 14:41:40 +0300 | [diff] [blame] | 165 | kfree(xattr_data); |
Mimi Zohar | 7102ebc | 2011-05-12 18:33:20 -0400 | [diff] [blame] | 166 | return evm_status; |
Mimi Zohar | 66dbc325 | 2011-03-15 16:12:09 -0400 | [diff] [blame] | 167 | } |
| 168 | |
| 169 | static int evm_protected_xattr(const char *req_xattr_name) |
| 170 | { |
| 171 | char **xattrname; |
| 172 | int namelen; |
| 173 | int found = 0; |
| 174 | |
| 175 | namelen = strlen(req_xattr_name); |
| 176 | for (xattrname = evm_config_xattrnames; *xattrname != NULL; xattrname++) { |
| 177 | if ((strlen(*xattrname) == namelen) |
| 178 | && (strncmp(req_xattr_name, *xattrname, namelen) == 0)) { |
| 179 | found = 1; |
| 180 | break; |
| 181 | } |
Mimi Zohar | cb72318 | 2011-03-09 14:40:44 -0500 | [diff] [blame] | 182 | if (strncmp(req_xattr_name, |
| 183 | *xattrname + XATTR_SECURITY_PREFIX_LEN, |
| 184 | strlen(req_xattr_name)) == 0) { |
| 185 | found = 1; |
| 186 | break; |
| 187 | } |
Mimi Zohar | 66dbc325 | 2011-03-15 16:12:09 -0400 | [diff] [blame] | 188 | } |
| 189 | return found; |
| 190 | } |
| 191 | |
| 192 | /** |
| 193 | * evm_verifyxattr - verify the integrity of the requested xattr |
| 194 | * @dentry: object of the verify xattr |
| 195 | * @xattr_name: requested xattr |
| 196 | * @xattr_value: requested xattr value |
| 197 | * @xattr_value_len: requested xattr value length |
| 198 | * |
| 199 | * Calculate the HMAC for the given dentry and verify it against the stored |
| 200 | * security.evm xattr. For performance, use the xattr value and length |
| 201 | * previously retrieved to calculate the HMAC. |
| 202 | * |
| 203 | * Returns the xattr integrity status. |
| 204 | * |
| 205 | * This function requires the caller to lock the inode's i_mutex before it |
| 206 | * is executed. |
| 207 | */ |
| 208 | enum integrity_status evm_verifyxattr(struct dentry *dentry, |
| 209 | const char *xattr_name, |
Dmitry Kasatkin | 2960e6c | 2011-05-06 11:34:13 +0300 | [diff] [blame] | 210 | void *xattr_value, size_t xattr_value_len, |
| 211 | struct integrity_iint_cache *iint) |
Mimi Zohar | 66dbc325 | 2011-03-15 16:12:09 -0400 | [diff] [blame] | 212 | { |
Mimi Zohar | 66dbc325 | 2011-03-15 16:12:09 -0400 | [diff] [blame] | 213 | if (!evm_initialized || !evm_protected_xattr(xattr_name)) |
| 214 | return INTEGRITY_UNKNOWN; |
| 215 | |
Dmitry Kasatkin | 2960e6c | 2011-05-06 11:34:13 +0300 | [diff] [blame] | 216 | if (!iint) { |
| 217 | iint = integrity_iint_find(dentry->d_inode); |
| 218 | if (!iint) |
| 219 | return INTEGRITY_UNKNOWN; |
| 220 | } |
| 221 | return evm_verify_hmac(dentry, xattr_name, xattr_value, |
Mimi Zohar | 66dbc325 | 2011-03-15 16:12:09 -0400 | [diff] [blame] | 222 | xattr_value_len, iint); |
Mimi Zohar | 66dbc325 | 2011-03-15 16:12:09 -0400 | [diff] [blame] | 223 | } |
| 224 | EXPORT_SYMBOL_GPL(evm_verifyxattr); |
| 225 | |
| 226 | /* |
Mimi Zohar | 7102ebc | 2011-05-12 18:33:20 -0400 | [diff] [blame] | 227 | * evm_verify_current_integrity - verify the dentry's metadata integrity |
| 228 | * @dentry: pointer to the affected dentry |
| 229 | * |
| 230 | * Verify and return the dentry's metadata integrity. The exceptions are |
| 231 | * before EVM is initialized or in 'fix' mode. |
| 232 | */ |
| 233 | static enum integrity_status evm_verify_current_integrity(struct dentry *dentry) |
| 234 | { |
| 235 | struct inode *inode = dentry->d_inode; |
| 236 | |
| 237 | if (!evm_initialized || !S_ISREG(inode->i_mode) || evm_fixmode) |
| 238 | return 0; |
| 239 | return evm_verify_hmac(dentry, NULL, NULL, 0, NULL); |
| 240 | } |
| 241 | |
Mimi Zohar | a924ce0 | 2011-08-11 01:22:30 -0400 | [diff] [blame] | 242 | /* |
| 243 | * evm_protect_xattr - protect the EVM extended attribute |
| 244 | * |
Mimi Zohar | bf6d0f5 | 2011-08-18 18:07:44 -0400 | [diff] [blame] | 245 | * Prevent security.evm from being modified or removed without the |
| 246 | * necessary permissions or when the existing value is invalid. |
| 247 | * |
| 248 | * The posix xattr acls are 'system' prefixed, which normally would not |
| 249 | * affect security.evm. An interesting side affect of writing posix xattr |
| 250 | * acls is their modifying of the i_mode, which is included in security.evm. |
| 251 | * For posix xattr acls only, permit security.evm, even if it currently |
| 252 | * doesn't exist, to be updated. |
Mimi Zohar | a924ce0 | 2011-08-11 01:22:30 -0400 | [diff] [blame] | 253 | */ |
| 254 | static int evm_protect_xattr(struct dentry *dentry, const char *xattr_name, |
| 255 | const void *xattr_value, size_t xattr_value_len) |
| 256 | { |
| 257 | enum integrity_status evm_status; |
| 258 | |
| 259 | if (strcmp(xattr_name, XATTR_NAME_EVM) == 0) { |
| 260 | if (!capable(CAP_SYS_ADMIN)) |
| 261 | return -EPERM; |
Mimi Zohar | bf6d0f5 | 2011-08-18 18:07:44 -0400 | [diff] [blame] | 262 | } else if (!evm_protected_xattr(xattr_name)) { |
| 263 | if (!posix_xattr_acl(xattr_name)) |
| 264 | return 0; |
| 265 | evm_status = evm_verify_current_integrity(dentry); |
| 266 | if ((evm_status == INTEGRITY_PASS) || |
Mimi Zohar | 566be59 | 2011-08-22 09:14:18 -0400 | [diff] [blame] | 267 | (evm_status == INTEGRITY_NOXATTRS)) |
Mimi Zohar | bf6d0f5 | 2011-08-18 18:07:44 -0400 | [diff] [blame] | 268 | return 0; |
Mimi Zohar | 9b97b6c | 2013-02-21 09:31:22 -0500 | [diff] [blame] | 269 | goto out; |
Mimi Zohar | bf6d0f5 | 2011-08-18 18:07:44 -0400 | [diff] [blame] | 270 | } |
Mimi Zohar | a924ce0 | 2011-08-11 01:22:30 -0400 | [diff] [blame] | 271 | evm_status = evm_verify_current_integrity(dentry); |
Mimi Zohar | 9b97b6c | 2013-02-21 09:31:22 -0500 | [diff] [blame] | 272 | out: |
| 273 | if (evm_status != INTEGRITY_PASS) |
| 274 | integrity_audit_msg(AUDIT_INTEGRITY_METADATA, dentry->d_inode, |
| 275 | dentry->d_name.name, "appraise_metadata", |
| 276 | integrity_status_msg[evm_status], |
| 277 | -EPERM, 0); |
Mimi Zohar | a924ce0 | 2011-08-11 01:22:30 -0400 | [diff] [blame] | 278 | return evm_status == INTEGRITY_PASS ? 0 : -EPERM; |
| 279 | } |
| 280 | |
Mimi Zohar | 66dbc325 | 2011-03-15 16:12:09 -0400 | [diff] [blame] | 281 | /** |
| 282 | * evm_inode_setxattr - protect the EVM extended attribute |
| 283 | * @dentry: pointer to the affected dentry |
| 284 | * @xattr_name: pointer to the affected extended attribute name |
| 285 | * @xattr_value: pointer to the new extended attribute value |
| 286 | * @xattr_value_len: pointer to the new extended attribute value length |
| 287 | * |
Mimi Zohar | 7102ebc | 2011-05-12 18:33:20 -0400 | [diff] [blame] | 288 | * Updating 'security.evm' requires CAP_SYS_ADMIN privileges and that |
| 289 | * the current value is valid. |
Mimi Zohar | 66dbc325 | 2011-03-15 16:12:09 -0400 | [diff] [blame] | 290 | */ |
| 291 | int evm_inode_setxattr(struct dentry *dentry, const char *xattr_name, |
| 292 | const void *xattr_value, size_t xattr_value_len) |
| 293 | { |
Mimi Zohar | a924ce0 | 2011-08-11 01:22:30 -0400 | [diff] [blame] | 294 | return evm_protect_xattr(dentry, xattr_name, xattr_value, |
| 295 | xattr_value_len); |
Mimi Zohar | 66dbc325 | 2011-03-15 16:12:09 -0400 | [diff] [blame] | 296 | } |
| 297 | |
| 298 | /** |
| 299 | * evm_inode_removexattr - protect the EVM extended attribute |
| 300 | * @dentry: pointer to the affected dentry |
| 301 | * @xattr_name: pointer to the affected extended attribute name |
| 302 | * |
Mimi Zohar | 7102ebc | 2011-05-12 18:33:20 -0400 | [diff] [blame] | 303 | * Removing 'security.evm' requires CAP_SYS_ADMIN privileges and that |
| 304 | * the current value is valid. |
Mimi Zohar | 66dbc325 | 2011-03-15 16:12:09 -0400 | [diff] [blame] | 305 | */ |
| 306 | int evm_inode_removexattr(struct dentry *dentry, const char *xattr_name) |
| 307 | { |
Mimi Zohar | a924ce0 | 2011-08-11 01:22:30 -0400 | [diff] [blame] | 308 | return evm_protect_xattr(dentry, xattr_name, NULL, 0); |
Mimi Zohar | 66dbc325 | 2011-03-15 16:12:09 -0400 | [diff] [blame] | 309 | } |
| 310 | |
| 311 | /** |
| 312 | * evm_inode_post_setxattr - update 'security.evm' to reflect the changes |
| 313 | * @dentry: pointer to the affected dentry |
| 314 | * @xattr_name: pointer to the affected extended attribute name |
| 315 | * @xattr_value: pointer to the new extended attribute value |
| 316 | * @xattr_value_len: pointer to the new extended attribute value length |
| 317 | * |
| 318 | * Update the HMAC stored in 'security.evm' to reflect the change. |
| 319 | * |
| 320 | * No need to take the i_mutex lock here, as this function is called from |
| 321 | * __vfs_setxattr_noperm(). The caller of which has taken the inode's |
| 322 | * i_mutex lock. |
| 323 | */ |
| 324 | void evm_inode_post_setxattr(struct dentry *dentry, const char *xattr_name, |
| 325 | const void *xattr_value, size_t xattr_value_len) |
| 326 | { |
Mimi Zohar | bf6d0f5 | 2011-08-18 18:07:44 -0400 | [diff] [blame] | 327 | if (!evm_initialized || (!evm_protected_xattr(xattr_name) |
| 328 | && !posix_xattr_acl(xattr_name))) |
Mimi Zohar | 66dbc325 | 2011-03-15 16:12:09 -0400 | [diff] [blame] | 329 | return; |
| 330 | |
| 331 | evm_update_evmxattr(dentry, xattr_name, xattr_value, xattr_value_len); |
| 332 | return; |
| 333 | } |
| 334 | |
| 335 | /** |
| 336 | * evm_inode_post_removexattr - update 'security.evm' after removing the xattr |
| 337 | * @dentry: pointer to the affected dentry |
| 338 | * @xattr_name: pointer to the affected extended attribute name |
| 339 | * |
| 340 | * Update the HMAC stored in 'security.evm' to reflect removal of the xattr. |
| 341 | */ |
| 342 | void evm_inode_post_removexattr(struct dentry *dentry, const char *xattr_name) |
| 343 | { |
| 344 | struct inode *inode = dentry->d_inode; |
| 345 | |
| 346 | if (!evm_initialized || !evm_protected_xattr(xattr_name)) |
| 347 | return; |
| 348 | |
| 349 | mutex_lock(&inode->i_mutex); |
| 350 | evm_update_evmxattr(dentry, xattr_name, NULL, 0); |
| 351 | mutex_unlock(&inode->i_mutex); |
| 352 | return; |
| 353 | } |
| 354 | |
| 355 | /** |
Mimi Zohar | 817b54a | 2011-05-13 12:53:38 -0400 | [diff] [blame] | 356 | * evm_inode_setattr - prevent updating an invalid EVM extended attribute |
| 357 | * @dentry: pointer to the affected dentry |
| 358 | */ |
| 359 | int evm_inode_setattr(struct dentry *dentry, struct iattr *attr) |
| 360 | { |
| 361 | unsigned int ia_valid = attr->ia_valid; |
| 362 | enum integrity_status evm_status; |
| 363 | |
Mimi Zohar | a924ce0 | 2011-08-11 01:22:30 -0400 | [diff] [blame] | 364 | if (!(ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID))) |
Mimi Zohar | 817b54a | 2011-05-13 12:53:38 -0400 | [diff] [blame] | 365 | return 0; |
| 366 | evm_status = evm_verify_current_integrity(dentry); |
Mimi Zohar | 566be59 | 2011-08-22 09:14:18 -0400 | [diff] [blame] | 367 | if ((evm_status == INTEGRITY_PASS) || |
| 368 | (evm_status == INTEGRITY_NOXATTRS)) |
| 369 | return 0; |
Mimi Zohar | 9b97b6c | 2013-02-21 09:31:22 -0500 | [diff] [blame] | 370 | integrity_audit_msg(AUDIT_INTEGRITY_METADATA, dentry->d_inode, |
| 371 | dentry->d_name.name, "appraise_metadata", |
| 372 | integrity_status_msg[evm_status], -EPERM, 0); |
Mimi Zohar | 566be59 | 2011-08-22 09:14:18 -0400 | [diff] [blame] | 373 | return -EPERM; |
Mimi Zohar | 817b54a | 2011-05-13 12:53:38 -0400 | [diff] [blame] | 374 | } |
| 375 | |
| 376 | /** |
Mimi Zohar | 66dbc325 | 2011-03-15 16:12:09 -0400 | [diff] [blame] | 377 | * evm_inode_post_setattr - update 'security.evm' after modifying metadata |
| 378 | * @dentry: pointer to the affected dentry |
| 379 | * @ia_valid: for the UID and GID status |
| 380 | * |
| 381 | * For now, update the HMAC stored in 'security.evm' to reflect UID/GID |
| 382 | * changes. |
| 383 | * |
| 384 | * This function is called from notify_change(), which expects the caller |
| 385 | * to lock the inode's i_mutex. |
| 386 | */ |
| 387 | void evm_inode_post_setattr(struct dentry *dentry, int ia_valid) |
| 388 | { |
| 389 | if (!evm_initialized) |
| 390 | return; |
| 391 | |
| 392 | if (ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID)) |
| 393 | evm_update_evmxattr(dentry, NULL, NULL, 0); |
| 394 | return; |
| 395 | } |
| 396 | |
Mimi Zohar | cb72318 | 2011-03-09 14:40:44 -0500 | [diff] [blame] | 397 | /* |
| 398 | * evm_inode_init_security - initializes security.evm |
| 399 | */ |
| 400 | int evm_inode_init_security(struct inode *inode, |
| 401 | const struct xattr *lsm_xattr, |
| 402 | struct xattr *evm_xattr) |
| 403 | { |
| 404 | struct evm_ima_xattr_data *xattr_data; |
| 405 | int rc; |
| 406 | |
| 407 | if (!evm_initialized || !evm_protected_xattr(lsm_xattr->name)) |
Mimi Zohar | 5a4730b | 2011-08-11 00:22:52 -0400 | [diff] [blame] | 408 | return 0; |
Mimi Zohar | cb72318 | 2011-03-09 14:40:44 -0500 | [diff] [blame] | 409 | |
| 410 | xattr_data = kzalloc(sizeof(*xattr_data), GFP_NOFS); |
| 411 | if (!xattr_data) |
| 412 | return -ENOMEM; |
| 413 | |
| 414 | xattr_data->type = EVM_XATTR_HMAC; |
| 415 | rc = evm_init_hmac(inode, lsm_xattr, xattr_data->digest); |
| 416 | if (rc < 0) |
| 417 | goto out; |
| 418 | |
| 419 | evm_xattr->value = xattr_data; |
| 420 | evm_xattr->value_len = sizeof(*xattr_data); |
Tetsuo Handa | 9548906 | 2013-07-25 05:44:02 +0900 | [diff] [blame] | 421 | evm_xattr->name = XATTR_EVM_SUFFIX; |
Mimi Zohar | cb72318 | 2011-03-09 14:40:44 -0500 | [diff] [blame] | 422 | return 0; |
| 423 | out: |
| 424 | kfree(xattr_data); |
| 425 | return rc; |
| 426 | } |
| 427 | EXPORT_SYMBOL_GPL(evm_inode_init_security); |
| 428 | |
Mimi Zohar | 66dbc325 | 2011-03-15 16:12:09 -0400 | [diff] [blame] | 429 | static int __init init_evm(void) |
| 430 | { |
| 431 | int error; |
| 432 | |
Mimi Zohar | 66dbc325 | 2011-03-15 16:12:09 -0400 | [diff] [blame] | 433 | error = evm_init_secfs(); |
| 434 | if (error < 0) { |
| 435 | printk(KERN_INFO "EVM: Error registering secfs\n"); |
| 436 | goto err; |
| 437 | } |
Dmitry Kasatkin | 15647eb | 2011-09-01 14:41:40 +0300 | [diff] [blame] | 438 | |
| 439 | return 0; |
Mimi Zohar | 66dbc325 | 2011-03-15 16:12:09 -0400 | [diff] [blame] | 440 | err: |
| 441 | return error; |
| 442 | } |
| 443 | |
Mimi Zohar | 66dbc325 | 2011-03-15 16:12:09 -0400 | [diff] [blame] | 444 | /* |
| 445 | * evm_display_config - list the EVM protected security extended attributes |
| 446 | */ |
| 447 | static int __init evm_display_config(void) |
| 448 | { |
| 449 | char **xattrname; |
| 450 | |
| 451 | for (xattrname = evm_config_xattrnames; *xattrname != NULL; xattrname++) |
| 452 | printk(KERN_INFO "EVM: %s\n", *xattrname); |
| 453 | return 0; |
| 454 | } |
| 455 | |
| 456 | pure_initcall(evm_display_config); |
| 457 | late_initcall(init_evm); |
| 458 | |
| 459 | MODULE_DESCRIPTION("Extended Verification Module"); |
| 460 | MODULE_LICENSE("GPL"); |