| .. | .. |
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| 1 | +// SPDX-License-Identifier: GPL-2.0-only |
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| 1 | 2 | /* |
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| 3 | + * Integrity Measurement Architecture |
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| 4 | + * |
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| 2 | 5 | * Copyright (C) 2005,2006,2007,2008 IBM Corporation |
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| 3 | 6 | * |
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| 4 | 7 | * Authors: |
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| .. | .. |
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| 7 | 10 | * Kylene Hall <kylene@us.ibm.com> |
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| 8 | 11 | * Mimi Zohar <zohar@us.ibm.com> |
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| 9 | 12 | * |
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| 10 | | - * This program is free software; you can redistribute it and/or |
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| 11 | | - * modify it under the terms of the GNU General Public License as |
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| 12 | | - * published by the Free Software Foundation, version 2 of the |
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| 13 | | - * License. |
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| 14 | | - * |
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| 15 | 13 | * File: ima_main.c |
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| 16 | 14 | * implements the IMA hooks: ima_bprm_check, ima_file_mmap, |
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| 17 | 15 | * and ima_file_check. |
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| 18 | 16 | */ |
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| 19 | 17 | |
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| 20 | | -#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
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| 21 | | - |
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| 22 | 18 | #include <linux/module.h> |
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| 23 | 19 | #include <linux/file.h> |
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| 24 | 20 | #include <linux/binfmts.h> |
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| 21 | +#include <linux/kernel_read_file.h> |
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| 25 | 22 | #include <linux/mount.h> |
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| 26 | 23 | #include <linux/mman.h> |
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| 27 | 24 | #include <linux/slab.h> |
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| .. | .. |
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| 41 | 38 | int ima_hash_algo = HASH_ALGO_SHA1; |
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| 42 | 39 | static int hash_setup_done; |
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| 43 | 40 | |
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| 41 | +static struct notifier_block ima_lsm_policy_notifier = { |
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| 42 | + .notifier_call = ima_lsm_policy_change, |
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| 43 | +}; |
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| 44 | + |
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| 44 | 45 | static int __init hash_setup(char *str) |
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| 45 | 46 | { |
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| 46 | 47 | struct ima_template_desc *template_desc = ima_template_desc_current(); |
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| .. | .. |
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| 50 | 51 | return 1; |
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| 51 | 52 | |
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| 52 | 53 | if (strcmp(template_desc->name, IMA_TEMPLATE_IMA_NAME) == 0) { |
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| 53 | | - if (strncmp(str, "sha1", 4) == 0) |
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| 54 | + if (strncmp(str, "sha1", 4) == 0) { |
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| 54 | 55 | ima_hash_algo = HASH_ALGO_SHA1; |
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| 55 | | - else if (strncmp(str, "md5", 3) == 0) |
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| 56 | + } else if (strncmp(str, "md5", 3) == 0) { |
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| 56 | 57 | ima_hash_algo = HASH_ALGO_MD5; |
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| 57 | | - else |
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| 58 | + } else { |
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| 59 | + pr_err("invalid hash algorithm \"%s\" for template \"%s\"", |
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| 60 | + str, IMA_TEMPLATE_IMA_NAME); |
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| 58 | 61 | return 1; |
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| 62 | + } |
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| 59 | 63 | goto out; |
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| 60 | 64 | } |
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| 61 | 65 | |
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| 62 | 66 | i = match_string(hash_algo_name, HASH_ALGO__LAST, str); |
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| 63 | | - if (i < 0) |
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| 67 | + if (i < 0) { |
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| 68 | + pr_err("invalid hash algorithm \"%s\"", str); |
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| 64 | 69 | return 1; |
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| 70 | + } |
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| 65 | 71 | |
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| 66 | 72 | ima_hash_algo = i; |
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| 67 | 73 | out: |
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| .. | .. |
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| 69 | 75 | return 1; |
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| 70 | 76 | } |
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| 71 | 77 | __setup("ima_hash=", hash_setup); |
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| 78 | + |
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| 79 | +/* Prevent mmap'ing a file execute that is already mmap'ed write */ |
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| 80 | +static int mmap_violation_check(enum ima_hooks func, struct file *file, |
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| 81 | + char **pathbuf, const char **pathname, |
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| 82 | + char *filename) |
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| 83 | +{ |
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| 84 | + struct inode *inode; |
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| 85 | + int rc = 0; |
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| 86 | + |
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| 87 | + if ((func == MMAP_CHECK) && mapping_writably_mapped(file->f_mapping)) { |
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| 88 | + rc = -ETXTBSY; |
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| 89 | + inode = file_inode(file); |
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| 90 | + |
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| 91 | + if (!*pathbuf) /* ima_rdwr_violation possibly pre-fetched */ |
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| 92 | + *pathname = ima_d_path(&file->f_path, pathbuf, |
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| 93 | + filename); |
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| 94 | + integrity_audit_msg(AUDIT_INTEGRITY_DATA, inode, *pathname, |
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| 95 | + "mmap_file", "mmapped_writers", rc, 0); |
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| 96 | + } |
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| 97 | + return rc; |
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| 98 | +} |
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| 72 | 99 | |
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| 73 | 100 | /* |
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| 74 | 101 | * ima_rdwr_violation_check |
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| .. | .. |
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| 103 | 130 | } else { |
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| 104 | 131 | if (must_measure) |
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| 105 | 132 | set_bit(IMA_MUST_MEASURE, &iint->atomic_flags); |
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| 106 | | - if ((atomic_read(&inode->i_writecount) > 0) && must_measure) |
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| 133 | + if (inode_is_open_for_write(inode) && must_measure) |
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| 107 | 134 | send_writers = true; |
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| 108 | 135 | } |
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| 109 | 136 | |
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| .. | .. |
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| 172 | 199 | { |
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| 173 | 200 | struct inode *inode = file_inode(file); |
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| 174 | 201 | struct integrity_iint_cache *iint = NULL; |
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| 175 | | - struct ima_template_desc *template_desc; |
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| 202 | + struct ima_template_desc *template_desc = NULL; |
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| 176 | 203 | char *pathbuf = NULL; |
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| 177 | 204 | char filename[NAME_MAX]; |
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| 178 | 205 | const char *pathname = NULL; |
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| 179 | 206 | int rc = 0, action, must_appraise = 0; |
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| 180 | 207 | int pcr = CONFIG_IMA_MEASURE_PCR_IDX; |
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| 181 | 208 | struct evm_ima_xattr_data *xattr_value = NULL; |
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| 209 | + struct modsig *modsig = NULL; |
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| 182 | 210 | int xattr_len = 0; |
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| 183 | 211 | bool violation_check; |
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| 184 | 212 | enum hash_algo hash_algo; |
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| .. | .. |
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| 190 | 218 | * bitmask based on the appraise/audit/measurement policy. |
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| 191 | 219 | * Included is the appraise submask. |
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| 192 | 220 | */ |
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| 193 | | - action = ima_get_action(inode, cred, secid, mask, func, &pcr); |
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| 221 | + action = ima_get_action(inode, cred, secid, mask, func, &pcr, |
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| 222 | + &template_desc, NULL); |
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| 194 | 223 | violation_check = ((func == FILE_CHECK || func == MMAP_CHECK) && |
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| 195 | 224 | (ima_policy_flag & IMA_MEASURE)); |
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| 196 | 225 | if (!action && !violation_check) |
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| .. | .. |
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| 268 | 297 | |
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| 269 | 298 | /* Nothing to do, just return existing appraised status */ |
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| 270 | 299 | if (!action) { |
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| 271 | | - if (must_appraise) |
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| 272 | | - rc = ima_get_cache_status(iint, func); |
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| 300 | + if (must_appraise) { |
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| 301 | + rc = mmap_violation_check(func, file, &pathbuf, |
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| 302 | + &pathname, filename); |
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| 303 | + if (!rc) |
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| 304 | + rc = ima_get_cache_status(iint, func); |
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| 305 | + } |
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| 273 | 306 | goto out_locked; |
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| 274 | 307 | } |
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| 275 | 308 | |
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| 276 | | - template_desc = ima_template_desc_current(); |
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| 277 | 309 | if ((action & IMA_APPRAISE_SUBMASK) || |
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| 278 | | - strcmp(template_desc->name, IMA_TEMPLATE_IMA_NAME) != 0) |
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| 310 | + strcmp(template_desc->name, IMA_TEMPLATE_IMA_NAME) != 0) { |
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| 279 | 311 | /* read 'security.ima' */ |
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| 280 | 312 | xattr_len = ima_read_xattr(file_dentry(file), &xattr_value); |
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| 281 | 313 | |
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| 314 | + /* |
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| 315 | + * Read the appended modsig if allowed by the policy, and allow |
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| 316 | + * an additional measurement list entry, if needed, based on the |
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| 317 | + * template format and whether the file was already measured. |
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| 318 | + */ |
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| 319 | + if (iint->flags & IMA_MODSIG_ALLOWED) { |
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| 320 | + rc = ima_read_modsig(func, buf, size, &modsig); |
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| 321 | + |
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| 322 | + if (!rc && ima_template_has_modsig(template_desc) && |
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| 323 | + iint->flags & IMA_MEASURED) |
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| 324 | + action |= IMA_MEASURE; |
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| 325 | + } |
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| 326 | + } |
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| 327 | + |
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| 282 | 328 | hash_algo = ima_get_hash_algo(xattr_value, xattr_len); |
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| 283 | 329 | |
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| 284 | | - rc = ima_collect_measurement(iint, file, buf, size, hash_algo); |
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| 330 | + rc = ima_collect_measurement(iint, file, buf, size, hash_algo, modsig); |
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| 285 | 331 | if (rc != 0 && rc != -EBADF && rc != -EINVAL) |
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| 286 | 332 | goto out_locked; |
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| 287 | 333 | |
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| .. | .. |
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| 290 | 336 | |
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| 291 | 337 | if (action & IMA_MEASURE) |
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| 292 | 338 | ima_store_measurement(iint, file, pathname, |
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| 293 | | - xattr_value, xattr_len, pcr); |
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| 339 | + xattr_value, xattr_len, modsig, pcr, |
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| 340 | + template_desc); |
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| 294 | 341 | if (rc == 0 && (action & IMA_APPRAISE_SUBMASK)) { |
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| 295 | | - inode_lock(inode); |
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| 296 | | - rc = ima_appraise_measurement(func, iint, file, pathname, |
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| 297 | | - xattr_value, xattr_len); |
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| 298 | | - inode_unlock(inode); |
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| 342 | + rc = ima_check_blacklist(iint, modsig, pcr); |
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| 343 | + if (rc != -EPERM) { |
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| 344 | + inode_lock(inode); |
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| 345 | + rc = ima_appraise_measurement(func, iint, file, |
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| 346 | + pathname, xattr_value, |
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| 347 | + xattr_len, modsig); |
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| 348 | + inode_unlock(inode); |
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| 349 | + } |
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| 350 | + if (!rc) |
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| 351 | + rc = mmap_violation_check(func, file, &pathbuf, |
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| 352 | + &pathname, filename); |
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| 299 | 353 | } |
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| 300 | 354 | if (action & IMA_AUDIT) |
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| 301 | 355 | ima_audit_measurement(iint, pathname); |
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| .. | .. |
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| 308 | 362 | rc = -EACCES; |
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| 309 | 363 | mutex_unlock(&iint->mutex); |
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| 310 | 364 | kfree(xattr_value); |
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| 365 | + ima_free_modsig(modsig); |
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| 311 | 366 | out: |
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| 312 | 367 | if (pathbuf) |
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| 313 | 368 | __putname(pathbuf); |
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| .. | .. |
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| 342 | 397 | } |
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| 343 | 398 | |
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| 344 | 399 | return 0; |
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| 400 | +} |
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| 401 | + |
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| 402 | +/** |
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| 403 | + * ima_file_mprotect - based on policy, limit mprotect change |
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| 404 | + * @prot: contains the protection that will be applied by the kernel. |
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| 405 | + * |
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| 406 | + * Files can be mmap'ed read/write and later changed to execute to circumvent |
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| 407 | + * IMA's mmap appraisal policy rules. Due to locking issues (mmap semaphore |
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| 408 | + * would be taken before i_mutex), files can not be measured or appraised at |
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| 409 | + * this point. Eliminate this integrity gap by denying the mprotect |
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| 410 | + * PROT_EXECUTE change, if an mmap appraise policy rule exists. |
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| 411 | + * |
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| 412 | + * On mprotect change success, return 0. On failure, return -EACESS. |
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| 413 | + */ |
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| 414 | +int ima_file_mprotect(struct vm_area_struct *vma, unsigned long prot) |
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| 415 | +{ |
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| 416 | + struct ima_template_desc *template; |
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| 417 | + struct file *file = vma->vm_file; |
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| 418 | + char filename[NAME_MAX]; |
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| 419 | + char *pathbuf = NULL; |
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| 420 | + const char *pathname = NULL; |
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| 421 | + struct inode *inode; |
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| 422 | + int result = 0; |
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| 423 | + int action; |
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| 424 | + u32 secid; |
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| 425 | + int pcr; |
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| 426 | + |
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| 427 | + /* Is mprotect making an mmap'ed file executable? */ |
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| 428 | + if (!(ima_policy_flag & IMA_APPRAISE) || !vma->vm_file || |
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| 429 | + !(prot & PROT_EXEC) || (vma->vm_flags & VM_EXEC)) |
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| 430 | + return 0; |
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| 431 | + |
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| 432 | + security_task_getsecid(current, &secid); |
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| 433 | + inode = file_inode(vma->vm_file); |
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| 434 | + action = ima_get_action(inode, current_cred(), secid, MAY_EXEC, |
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| 435 | + MMAP_CHECK, &pcr, &template, 0); |
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| 436 | + |
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| 437 | + /* Is the mmap'ed file in policy? */ |
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| 438 | + if (!(action & (IMA_MEASURE | IMA_APPRAISE_SUBMASK))) |
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| 439 | + return 0; |
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| 440 | + |
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| 441 | + if (action & IMA_APPRAISE_SUBMASK) |
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| 442 | + result = -EPERM; |
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| 443 | + |
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| 444 | + file = vma->vm_file; |
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| 445 | + pathname = ima_d_path(&file->f_path, &pathbuf, filename); |
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| 446 | + integrity_audit_msg(AUDIT_INTEGRITY_DATA, inode, pathname, |
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| 447 | + "collect_data", "failed-mprotect", result, 0); |
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| 448 | + if (pathbuf) |
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| 449 | + __putname(pathbuf); |
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| 450 | + |
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| 451 | + return result; |
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| 345 | 452 | } |
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| 346 | 453 | |
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| 347 | 454 | /** |
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| .. | .. |
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| 395 | 502 | EXPORT_SYMBOL_GPL(ima_file_check); |
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| 396 | 503 | |
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| 397 | 504 | /** |
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| 505 | + * ima_file_hash - return the stored measurement if a file has been hashed and |
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| 506 | + * is in the iint cache. |
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| 507 | + * @file: pointer to the file |
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| 508 | + * @buf: buffer in which to store the hash |
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| 509 | + * @buf_size: length of the buffer |
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| 510 | + * |
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| 511 | + * On success, return the hash algorithm (as defined in the enum hash_algo). |
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| 512 | + * If buf is not NULL, this function also outputs the hash into buf. |
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| 513 | + * If the hash is larger than buf_size, then only buf_size bytes will be copied. |
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| 514 | + * It generally just makes sense to pass a buffer capable of holding the largest |
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| 515 | + * possible hash: IMA_MAX_DIGEST_SIZE. |
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| 516 | + * The file hash returned is based on the entire file, including the appended |
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| 517 | + * signature. |
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| 518 | + * |
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| 519 | + * If IMA is disabled or if no measurement is available, return -EOPNOTSUPP. |
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| 520 | + * If the parameters are incorrect, return -EINVAL. |
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| 521 | + */ |
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| 522 | +int ima_file_hash(struct file *file, char *buf, size_t buf_size) |
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| 523 | +{ |
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| 524 | + struct inode *inode; |
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| 525 | + struct integrity_iint_cache *iint; |
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| 526 | + int hash_algo; |
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| 527 | + |
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| 528 | + if (!file) |
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| 529 | + return -EINVAL; |
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| 530 | + |
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| 531 | + if (!ima_policy_flag) |
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| 532 | + return -EOPNOTSUPP; |
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| 533 | + |
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| 534 | + inode = file_inode(file); |
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| 535 | + iint = integrity_iint_find(inode); |
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| 536 | + if (!iint) |
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| 537 | + return -EOPNOTSUPP; |
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| 538 | + |
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| 539 | + mutex_lock(&iint->mutex); |
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| 540 | + |
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| 541 | + /* |
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| 542 | + * ima_file_hash can be called when ima_collect_measurement has still |
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| 543 | + * not been called, we might not always have a hash. |
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| 544 | + */ |
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| 545 | + if (!iint->ima_hash) { |
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| 546 | + mutex_unlock(&iint->mutex); |
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| 547 | + return -EOPNOTSUPP; |
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| 548 | + } |
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| 549 | + |
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| 550 | + if (buf) { |
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| 551 | + size_t copied_size; |
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| 552 | + |
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| 553 | + copied_size = min_t(size_t, iint->ima_hash->length, buf_size); |
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| 554 | + memcpy(buf, iint->ima_hash->digest, copied_size); |
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| 555 | + } |
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| 556 | + hash_algo = iint->ima_hash->algo; |
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| 557 | + mutex_unlock(&iint->mutex); |
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| 558 | + |
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| 559 | + return hash_algo; |
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| 560 | +} |
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| 561 | +EXPORT_SYMBOL_GPL(ima_file_hash); |
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| 562 | + |
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| 563 | +/** |
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| 564 | + * ima_post_create_tmpfile - mark newly created tmpfile as new |
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| 565 | + * @file : newly created tmpfile |
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| 566 | + * |
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| 567 | + * No measuring, appraising or auditing of newly created tmpfiles is needed. |
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| 568 | + * Skip calling process_measurement(), but indicate which newly, created |
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| 569 | + * tmpfiles are in policy. |
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| 570 | + */ |
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| 571 | +void ima_post_create_tmpfile(struct inode *inode) |
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| 572 | +{ |
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| 573 | + struct integrity_iint_cache *iint; |
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| 574 | + int must_appraise; |
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| 575 | + |
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| 576 | + must_appraise = ima_must_appraise(inode, MAY_ACCESS, FILE_CHECK); |
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| 577 | + if (!must_appraise) |
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| 578 | + return; |
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| 579 | + |
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| 580 | + /* Nothing to do if we can't allocate memory */ |
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| 581 | + iint = integrity_inode_get(inode); |
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| 582 | + if (!iint) |
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| 583 | + return; |
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| 584 | + |
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| 585 | + /* needed for writing the security xattrs */ |
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| 586 | + set_bit(IMA_UPDATE_XATTR, &iint->atomic_flags); |
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| 587 | + iint->ima_file_status = INTEGRITY_PASS; |
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| 588 | +} |
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| 589 | + |
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| 590 | +/** |
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| 398 | 591 | * ima_post_path_mknod - mark as a new inode |
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| 399 | 592 | * @dentry: newly created dentry |
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| 400 | 593 | * |
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| .. | .. |
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| 411 | 604 | if (!must_appraise) |
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| 412 | 605 | return; |
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| 413 | 606 | |
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| 607 | + /* Nothing to do if we can't allocate memory */ |
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| 414 | 608 | iint = integrity_inode_get(inode); |
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| 415 | | - if (iint) |
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| 416 | | - iint->flags |= IMA_NEW_FILE; |
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| 609 | + if (!iint) |
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| 610 | + return; |
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| 611 | + |
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| 612 | + /* needed for re-opening empty files */ |
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| 613 | + iint->flags |= IMA_NEW_FILE; |
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| 417 | 614 | } |
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| 418 | 615 | |
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| 419 | 616 | /** |
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| 420 | 617 | * ima_read_file - pre-measure/appraise hook decision based on policy |
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| 421 | 618 | * @file: pointer to the file to be measured/appraised/audit |
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| 422 | 619 | * @read_id: caller identifier |
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| 620 | + * @contents: whether a subsequent call will be made to ima_post_read_file() |
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| 423 | 621 | * |
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| 424 | 622 | * Permit reading a file based on policy. The policy rules are written |
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| 425 | 623 | * in terms of the policy identifier. Appraising the integrity of |
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| .. | .. |
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| 427 | 625 | * |
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| 428 | 626 | * For permission return 0, otherwise return -EACCES. |
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| 429 | 627 | */ |
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| 430 | | -int ima_read_file(struct file *file, enum kernel_read_file_id read_id) |
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| 628 | +int ima_read_file(struct file *file, enum kernel_read_file_id read_id, |
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| 629 | + bool contents) |
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| 431 | 630 | { |
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| 631 | + enum ima_hooks func; |
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| 632 | + u32 secid; |
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| 633 | + |
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| 432 | 634 | /* |
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| 433 | | - * READING_FIRMWARE_PREALLOC_BUFFER |
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| 434 | | - * |
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| 435 | 635 | * Do devices using pre-allocated memory run the risk of the |
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| 436 | 636 | * firmware being accessible to the device prior to the completion |
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| 437 | 637 | * of IMA's signature verification any more than when using two |
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| 438 | | - * buffers? |
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| 638 | + * buffers? It may be desirable to include the buffer address |
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| 639 | + * in this API and walk all the dma_map_single() mappings to check. |
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| 439 | 640 | */ |
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| 440 | | - return 0; |
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| 641 | + |
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| 642 | + /* |
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| 643 | + * There will be a call made to ima_post_read_file() with |
|---|
| 644 | + * a filled buffer, so we don't need to perform an extra |
|---|
| 645 | + * read early here. |
|---|
| 646 | + */ |
|---|
| 647 | + if (contents) |
|---|
| 648 | + return 0; |
|---|
| 649 | + |
|---|
| 650 | + /* Read entire file for all partial reads. */ |
|---|
| 651 | + func = read_idmap[read_id] ?: FILE_CHECK; |
|---|
| 652 | + security_task_getsecid(current, &secid); |
|---|
| 653 | + return process_measurement(file, current_cred(), secid, NULL, |
|---|
| 654 | + 0, MAY_READ, func); |
|---|
| 441 | 655 | } |
|---|
| 442 | 656 | |
|---|
| 443 | | -static int read_idmap[READING_MAX_ID] = { |
|---|
| 657 | +const int read_idmap[READING_MAX_ID] = { |
|---|
| 444 | 658 | [READING_FIRMWARE] = FIRMWARE_CHECK, |
|---|
| 445 | | - [READING_FIRMWARE_PREALLOC_BUFFER] = FIRMWARE_CHECK, |
|---|
| 446 | 659 | [READING_MODULE] = MODULE_CHECK, |
|---|
| 447 | 660 | [READING_KEXEC_IMAGE] = KEXEC_KERNEL_CHECK, |
|---|
| 448 | 661 | [READING_KEXEC_INITRAMFS] = KEXEC_INITRAMFS_CHECK, |
|---|
| .. | .. |
|---|
| 468 | 681 | enum ima_hooks func; |
|---|
| 469 | 682 | u32 secid; |
|---|
| 470 | 683 | |
|---|
| 471 | | - if (!file && read_id == READING_FIRMWARE) { |
|---|
| 472 | | - if ((ima_appraise & IMA_APPRAISE_FIRMWARE) && |
|---|
| 473 | | - (ima_appraise & IMA_APPRAISE_ENFORCE)) { |
|---|
| 474 | | - pr_err("Prevent firmware loading_store.\n"); |
|---|
| 475 | | - return -EACCES; /* INTEGRITY_UNKNOWN */ |
|---|
| 476 | | - } |
|---|
| 477 | | - return 0; |
|---|
| 478 | | - } |
|---|
| 479 | | - |
|---|
| 480 | 684 | /* permit signed certs */ |
|---|
| 481 | 685 | if (!file && read_id == READING_X509_CERTIFICATE) |
|---|
| 482 | 686 | return 0; |
|---|
| .. | .. |
|---|
| 496 | 700 | /** |
|---|
| 497 | 701 | * ima_load_data - appraise decision based on policy |
|---|
| 498 | 702 | * @id: kernel load data caller identifier |
|---|
| 703 | + * @contents: whether the full contents will be available in a later |
|---|
| 704 | + * call to ima_post_load_data(). |
|---|
| 499 | 705 | * |
|---|
| 500 | 706 | * Callers of this LSM hook can not measure, appraise, or audit the |
|---|
| 501 | 707 | * data provided by userspace. Enforce policy rules requring a file |
|---|
| .. | .. |
|---|
| 503 | 709 | * |
|---|
| 504 | 710 | * For permission return 0, otherwise return -EACCES. |
|---|
| 505 | 711 | */ |
|---|
| 506 | | -int ima_load_data(enum kernel_load_data_id id) |
|---|
| 712 | +int ima_load_data(enum kernel_load_data_id id, bool contents) |
|---|
| 507 | 713 | { |
|---|
| 508 | | - bool sig_enforce; |
|---|
| 714 | + bool ima_enforce, sig_enforce; |
|---|
| 509 | 715 | |
|---|
| 510 | | - if ((ima_appraise & IMA_APPRAISE_ENFORCE) != IMA_APPRAISE_ENFORCE) |
|---|
| 511 | | - return 0; |
|---|
| 716 | + ima_enforce = |
|---|
| 717 | + (ima_appraise & IMA_APPRAISE_ENFORCE) == IMA_APPRAISE_ENFORCE; |
|---|
| 512 | 718 | |
|---|
| 513 | 719 | switch (id) { |
|---|
| 514 | 720 | case LOADING_KEXEC_IMAGE: |
|---|
| 515 | | - if (ima_appraise & IMA_APPRAISE_KEXEC) { |
|---|
| 721 | + if (IS_ENABLED(CONFIG_KEXEC_SIG) |
|---|
| 722 | + && arch_ima_get_secureboot()) { |
|---|
| 723 | + pr_err("impossible to appraise a kernel image without a file descriptor; try using kexec_file_load syscall.\n"); |
|---|
| 724 | + return -EACCES; |
|---|
| 725 | + } |
|---|
| 726 | + |
|---|
| 727 | + if (ima_enforce && (ima_appraise & IMA_APPRAISE_KEXEC)) { |
|---|
| 516 | 728 | pr_err("impossible to appraise a kernel image without a file descriptor; try using kexec_file_load syscall.\n"); |
|---|
| 517 | 729 | return -EACCES; /* INTEGRITY_UNKNOWN */ |
|---|
| 518 | 730 | } |
|---|
| 519 | 731 | break; |
|---|
| 520 | 732 | case LOADING_FIRMWARE: |
|---|
| 521 | | - if (ima_appraise & IMA_APPRAISE_FIRMWARE) { |
|---|
| 733 | + if (ima_enforce && (ima_appraise & IMA_APPRAISE_FIRMWARE) && !contents) { |
|---|
| 522 | 734 | pr_err("Prevent firmware sysfs fallback loading.\n"); |
|---|
| 523 | 735 | return -EACCES; /* INTEGRITY_UNKNOWN */ |
|---|
| 524 | 736 | } |
|---|
| .. | .. |
|---|
| 526 | 738 | case LOADING_MODULE: |
|---|
| 527 | 739 | sig_enforce = is_module_sig_enforced(); |
|---|
| 528 | 740 | |
|---|
| 529 | | - if (!sig_enforce && (ima_appraise & IMA_APPRAISE_MODULES)) { |
|---|
| 741 | + if (ima_enforce && (!sig_enforce |
|---|
| 742 | + && (ima_appraise & IMA_APPRAISE_MODULES))) { |
|---|
| 530 | 743 | pr_err("impossible to appraise a module without a file descriptor. sig_enforce kernel parameter might help\n"); |
|---|
| 531 | 744 | return -EACCES; /* INTEGRITY_UNKNOWN */ |
|---|
| 532 | 745 | } |
|---|
| .. | .. |
|---|
| 534 | 747 | break; |
|---|
| 535 | 748 | } |
|---|
| 536 | 749 | return 0; |
|---|
| 750 | +} |
|---|
| 751 | + |
|---|
| 752 | +/** |
|---|
| 753 | + * ima_post_load_data - appraise decision based on policy |
|---|
| 754 | + * @buf: pointer to in memory file contents |
|---|
| 755 | + * @size: size of in memory file contents |
|---|
| 756 | + * @id: kernel load data caller identifier |
|---|
| 757 | + * @description: @id-specific description of contents |
|---|
| 758 | + * |
|---|
| 759 | + * Measure/appraise/audit in memory buffer based on policy. Policy rules |
|---|
| 760 | + * are written in terms of a policy identifier. |
|---|
| 761 | + * |
|---|
| 762 | + * On success return 0. On integrity appraisal error, assuming the file |
|---|
| 763 | + * is in policy and IMA-appraisal is in enforcing mode, return -EACCES. |
|---|
| 764 | + */ |
|---|
| 765 | +int ima_post_load_data(char *buf, loff_t size, |
|---|
| 766 | + enum kernel_load_data_id load_id, |
|---|
| 767 | + char *description) |
|---|
| 768 | +{ |
|---|
| 769 | + if (load_id == LOADING_FIRMWARE) { |
|---|
| 770 | + if ((ima_appraise & IMA_APPRAISE_FIRMWARE) && |
|---|
| 771 | + (ima_appraise & IMA_APPRAISE_ENFORCE)) { |
|---|
| 772 | + pr_err("Prevent firmware loading_store.\n"); |
|---|
| 773 | + return -EACCES; /* INTEGRITY_UNKNOWN */ |
|---|
| 774 | + } |
|---|
| 775 | + return 0; |
|---|
| 776 | + } |
|---|
| 777 | + |
|---|
| 778 | + return 0; |
|---|
| 779 | +} |
|---|
| 780 | + |
|---|
| 781 | +/* |
|---|
| 782 | + * process_buffer_measurement - Measure the buffer to ima log. |
|---|
| 783 | + * @inode: inode associated with the object being measured (NULL for KEY_CHECK) |
|---|
| 784 | + * @buf: pointer to the buffer that needs to be added to the log. |
|---|
| 785 | + * @size: size of buffer(in bytes). |
|---|
| 786 | + * @eventname: event name to be used for the buffer entry. |
|---|
| 787 | + * @func: IMA hook |
|---|
| 788 | + * @pcr: pcr to extend the measurement |
|---|
| 789 | + * @keyring: keyring name to determine the action to be performed |
|---|
| 790 | + * |
|---|
| 791 | + * Based on policy, the buffer is measured into the ima log. |
|---|
| 792 | + */ |
|---|
| 793 | +void process_buffer_measurement(struct inode *inode, const void *buf, int size, |
|---|
| 794 | + const char *eventname, enum ima_hooks func, |
|---|
| 795 | + int pcr, const char *keyring) |
|---|
| 796 | +{ |
|---|
| 797 | + int ret = 0; |
|---|
| 798 | + const char *audit_cause = "ENOMEM"; |
|---|
| 799 | + struct ima_template_entry *entry = NULL; |
|---|
| 800 | + struct integrity_iint_cache iint = {}; |
|---|
| 801 | + struct ima_event_data event_data = {.iint = &iint, |
|---|
| 802 | + .filename = eventname, |
|---|
| 803 | + .buf = buf, |
|---|
| 804 | + .buf_len = size}; |
|---|
| 805 | + struct ima_template_desc *template = NULL; |
|---|
| 806 | + struct { |
|---|
| 807 | + struct ima_digest_data hdr; |
|---|
| 808 | + char digest[IMA_MAX_DIGEST_SIZE]; |
|---|
| 809 | + } hash = {}; |
|---|
| 810 | + int violation = 0; |
|---|
| 811 | + int action = 0; |
|---|
| 812 | + u32 secid; |
|---|
| 813 | + |
|---|
| 814 | + if (!ima_policy_flag) |
|---|
| 815 | + return; |
|---|
| 816 | + |
|---|
| 817 | + /* |
|---|
| 818 | + * Both LSM hooks and auxilary based buffer measurements are |
|---|
| 819 | + * based on policy. To avoid code duplication, differentiate |
|---|
| 820 | + * between the LSM hooks and auxilary buffer measurements, |
|---|
| 821 | + * retrieving the policy rule information only for the LSM hook |
|---|
| 822 | + * buffer measurements. |
|---|
| 823 | + */ |
|---|
| 824 | + if (func) { |
|---|
| 825 | + security_task_getsecid(current, &secid); |
|---|
| 826 | + action = ima_get_action(inode, current_cred(), secid, 0, func, |
|---|
| 827 | + &pcr, &template, keyring); |
|---|
| 828 | + if (!(action & IMA_MEASURE)) |
|---|
| 829 | + return; |
|---|
| 830 | + } |
|---|
| 831 | + |
|---|
| 832 | + if (!pcr) |
|---|
| 833 | + pcr = CONFIG_IMA_MEASURE_PCR_IDX; |
|---|
| 834 | + |
|---|
| 835 | + if (!template) { |
|---|
| 836 | + template = lookup_template_desc("ima-buf"); |
|---|
| 837 | + ret = template_desc_init_fields(template->fmt, |
|---|
| 838 | + &(template->fields), |
|---|
| 839 | + &(template->num_fields)); |
|---|
| 840 | + if (ret < 0) { |
|---|
| 841 | + pr_err("template %s init failed, result: %d\n", |
|---|
| 842 | + (strlen(template->name) ? |
|---|
| 843 | + template->name : template->fmt), ret); |
|---|
| 844 | + return; |
|---|
| 845 | + } |
|---|
| 846 | + } |
|---|
| 847 | + |
|---|
| 848 | + iint.ima_hash = &hash.hdr; |
|---|
| 849 | + iint.ima_hash->algo = ima_hash_algo; |
|---|
| 850 | + iint.ima_hash->length = hash_digest_size[ima_hash_algo]; |
|---|
| 851 | + |
|---|
| 852 | + ret = ima_calc_buffer_hash(buf, size, iint.ima_hash); |
|---|
| 853 | + if (ret < 0) { |
|---|
| 854 | + audit_cause = "hashing_error"; |
|---|
| 855 | + goto out; |
|---|
| 856 | + } |
|---|
| 857 | + |
|---|
| 858 | + ret = ima_alloc_init_template(&event_data, &entry, template); |
|---|
| 859 | + if (ret < 0) { |
|---|
| 860 | + audit_cause = "alloc_entry"; |
|---|
| 861 | + goto out; |
|---|
| 862 | + } |
|---|
| 863 | + |
|---|
| 864 | + ret = ima_store_template(entry, violation, NULL, buf, pcr); |
|---|
| 865 | + if (ret < 0) { |
|---|
| 866 | + audit_cause = "store_entry"; |
|---|
| 867 | + ima_free_template_entry(entry); |
|---|
| 868 | + } |
|---|
| 869 | + |
|---|
| 870 | +out: |
|---|
| 871 | + if (ret < 0) |
|---|
| 872 | + integrity_audit_message(AUDIT_INTEGRITY_PCR, NULL, eventname, |
|---|
| 873 | + func_measure_str(func), |
|---|
| 874 | + audit_cause, ret, 0, ret); |
|---|
| 875 | + |
|---|
| 876 | + return; |
|---|
| 877 | +} |
|---|
| 878 | + |
|---|
| 879 | +/** |
|---|
| 880 | + * ima_kexec_cmdline - measure kexec cmdline boot args |
|---|
| 881 | + * @kernel_fd: file descriptor of the kexec kernel being loaded |
|---|
| 882 | + * @buf: pointer to buffer |
|---|
| 883 | + * @size: size of buffer |
|---|
| 884 | + * |
|---|
| 885 | + * Buffers can only be measured, not appraised. |
|---|
| 886 | + */ |
|---|
| 887 | +void ima_kexec_cmdline(int kernel_fd, const void *buf, int size) |
|---|
| 888 | +{ |
|---|
| 889 | + struct fd f; |
|---|
| 890 | + |
|---|
| 891 | + if (!buf || !size) |
|---|
| 892 | + return; |
|---|
| 893 | + |
|---|
| 894 | + f = fdget(kernel_fd); |
|---|
| 895 | + if (!f.file) |
|---|
| 896 | + return; |
|---|
| 897 | + |
|---|
| 898 | + process_buffer_measurement(file_inode(f.file), buf, size, |
|---|
| 899 | + "kexec-cmdline", KEXEC_CMDLINE, 0, NULL); |
|---|
| 900 | + fdput(f); |
|---|
| 537 | 901 | } |
|---|
| 538 | 902 | |
|---|
| 539 | 903 | static int __init init_ima(void) |
|---|
| .. | .. |
|---|
| 553 | 917 | error = ima_init(); |
|---|
| 554 | 918 | } |
|---|
| 555 | 919 | |
|---|
| 920 | + if (error) |
|---|
| 921 | + return error; |
|---|
| 922 | + |
|---|
| 923 | + error = register_blocking_lsm_notifier(&ima_lsm_policy_notifier); |
|---|
| 924 | + if (error) |
|---|
| 925 | + pr_warn("Couldn't register LSM notifier, error %d\n", error); |
|---|
| 926 | + |
|---|
| 556 | 927 | if (!error) |
|---|
| 557 | 928 | ima_update_policy_flag(); |
|---|
| 558 | 929 | |
|---|
| .. | .. |
|---|
| 560 | 931 | } |
|---|
| 561 | 932 | |
|---|
| 562 | 933 | late_initcall(init_ima); /* Start IMA after the TPM is available */ |
|---|
| 563 | | - |
|---|
| 564 | | -MODULE_DESCRIPTION("Integrity Measurement Architecture"); |
|---|
| 565 | | -MODULE_LICENSE("GPL"); |
|---|