From 23fa18eaa71266feff7ba8d83022d9e1cc83c65a Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Fri, 10 May 2024 07:42:03 +0000
Subject: [PATCH] disable pwm7
---
kernel/security/integrity/ima/ima_policy.c | 874 +++++++++++++++++++++++++++++++++++++++++++++++++--------
1 files changed, 742 insertions(+), 132 deletions(-)
diff --git a/kernel/security/integrity/ima/ima_policy.c b/kernel/security/integrity/ima/ima_policy.c
index 2d5a3da..1c403e8 100644
--- a/kernel/security/integrity/ima/ima_policy.c
+++ b/kernel/security/integrity/ima/ima_policy.c
@@ -1,17 +1,15 @@
+// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2008 IBM Corporation
* Author: Mimi Zohar <zohar@us.ibm.com>
*
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, version 2 of the License.
- *
* ima_policy.c
* - initialize default measure policy rules
- *
*/
-#include <linux/module.h>
+
+#include <linux/init.h>
#include <linux/list.h>
+#include <linux/kernel_read_file.h>
#include <linux/fs.h>
#include <linux/security.h>
#include <linux/magic.h>
@@ -20,6 +18,7 @@
#include <linux/rculist.h>
#include <linux/genhd.h>
#include <linux/seq_file.h>
+#include <linux/ima.h>
#include "ima.h"
@@ -34,6 +33,7 @@
#define IMA_EUID 0x0080
#define IMA_PCR 0x0100
#define IMA_FSNAME 0x0200
+#define IMA_KEYRINGS 0x0400
#define UNKNOWN 0
#define MEASURE 0x0001 /* same as IMA_MEASURE */
@@ -45,7 +45,7 @@
#define DONT_HASH 0x0200
#define INVALID_PCR(a) (((a) < 0) || \
- (a) >= (FIELD_SIZEOF(struct integrity_iint_cache, measured_pcrs) * 8))
+ (a) >= (sizeof_field(struct integrity_iint_cache, measured_pcrs) * 8))
int ima_policy_flag;
static int temp_ima_appraise;
@@ -57,6 +57,13 @@
};
enum policy_types { ORIGINAL_TCB = 1, DEFAULT_TCB };
+
+enum policy_rule_list { IMA_DEFAULT_POLICY = 1, IMA_CUSTOM_POLICY };
+
+struct ima_rule_opt_list {
+ size_t count;
+ char *items[];
+};
struct ima_rule_entry {
struct list_head list;
@@ -73,10 +80,12 @@
int pcr;
struct {
void *rule; /* LSM file metadata specific */
- void *args_p; /* audit value */
+ char *args_p; /* audit value */
int type; /* audit type */
} lsm[MAX_LSM_RULES];
char *fsname;
+ struct ima_rule_opt_list *keyrings; /* Measure keys added to these keyrings */
+ struct ima_template_desc *template;
};
/*
@@ -104,7 +113,8 @@
.flags = IMA_FSMAGIC},
{.action = DONT_MEASURE, .fsmagic = CGROUP2_SUPER_MAGIC,
.flags = IMA_FSMAGIC},
- {.action = DONT_MEASURE, .fsmagic = NSFS_MAGIC, .flags = IMA_FSMAGIC}
+ {.action = DONT_MEASURE, .fsmagic = NSFS_MAGIC, .flags = IMA_FSMAGIC},
+ {.action = DONT_MEASURE, .fsmagic = EFIVARFS_MAGIC, .flags = IMA_FSMAGIC}
};
static struct ima_rule_entry original_measurement_rules[] __ro_after_init = {
@@ -147,6 +157,7 @@
{.action = DONT_APPRAISE, .fsmagic = SELINUX_MAGIC, .flags = IMA_FSMAGIC},
{.action = DONT_APPRAISE, .fsmagic = SMACK_MAGIC, .flags = IMA_FSMAGIC},
{.action = DONT_APPRAISE, .fsmagic = NSFS_MAGIC, .flags = IMA_FSMAGIC},
+ {.action = DONT_APPRAISE, .fsmagic = EFIVARFS_MAGIC, .flags = IMA_FSMAGIC},
{.action = DONT_APPRAISE, .fsmagic = CGROUP_SUPER_MAGIC, .flags = IMA_FSMAGIC},
{.action = DONT_APPRAISE, .fsmagic = CGROUP2_SUPER_MAGIC, .flags = IMA_FSMAGIC},
#ifdef CONFIG_IMA_WRITE_POLICY
@@ -193,6 +204,9 @@
.flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
};
+/* An array of architecture specific rules */
+static struct ima_rule_entry *arch_policy_entry __ro_after_init;
+
static LIST_HEAD(ima_default_rules);
static LIST_HEAD(ima_policy_rules);
static LIST_HEAD(ima_temp_rules);
@@ -228,6 +242,8 @@
ima_use_secure_boot = true;
else if (strcmp(p, "fail_securely") == 0)
ima_fail_unverifiable_sigs = true;
+ else
+ pr_err("policy \"%s\" not found", p);
}
return 1;
@@ -241,48 +257,256 @@
}
__setup("ima_appraise_tcb", default_appraise_policy_setup);
+static struct ima_rule_opt_list *ima_alloc_rule_opt_list(const substring_t *src)
+{
+ struct ima_rule_opt_list *opt_list;
+ size_t count = 0;
+ char *src_copy;
+ char *cur, *next;
+ size_t i;
+
+ src_copy = match_strdup(src);
+ if (!src_copy)
+ return ERR_PTR(-ENOMEM);
+
+ next = src_copy;
+ while ((cur = strsep(&next, "|"))) {
+ /* Don't accept an empty list item */
+ if (!(*cur)) {
+ kfree(src_copy);
+ return ERR_PTR(-EINVAL);
+ }
+ count++;
+ }
+
+ /* Don't accept an empty list */
+ if (!count) {
+ kfree(src_copy);
+ return ERR_PTR(-EINVAL);
+ }
+
+ opt_list = kzalloc(struct_size(opt_list, items, count), GFP_KERNEL);
+ if (!opt_list) {
+ kfree(src_copy);
+ return ERR_PTR(-ENOMEM);
+ }
+
+ /*
+ * strsep() has already replaced all instances of '|' with '\0',
+ * leaving a byte sequence of NUL-terminated strings. Reference each
+ * string with the array of items.
+ *
+ * IMPORTANT: Ownership of the allocated buffer is transferred from
+ * src_copy to the first element in the items array. To free the
+ * buffer, kfree() must only be called on the first element of the
+ * array.
+ */
+ for (i = 0, cur = src_copy; i < count; i++) {
+ opt_list->items[i] = cur;
+ cur = strchr(cur, '\0') + 1;
+ }
+ opt_list->count = count;
+
+ return opt_list;
+}
+
+static void ima_free_rule_opt_list(struct ima_rule_opt_list *opt_list)
+{
+ if (!opt_list)
+ return;
+
+ if (opt_list->count) {
+ kfree(opt_list->items[0]);
+ opt_list->count = 0;
+ }
+
+ kfree(opt_list);
+}
+
+static void ima_lsm_free_rule(struct ima_rule_entry *entry)
+{
+ int i;
+
+ for (i = 0; i < MAX_LSM_RULES; i++) {
+ ima_filter_rule_free(entry->lsm[i].rule);
+ kfree(entry->lsm[i].args_p);
+ }
+}
+
+static void ima_free_rule(struct ima_rule_entry *entry)
+{
+ if (!entry)
+ return;
+
+ /*
+ * entry->template->fields may be allocated in ima_parse_rule() but that
+ * reference is owned by the corresponding ima_template_desc element in
+ * the defined_templates list and cannot be freed here
+ */
+ kfree(entry->fsname);
+ ima_free_rule_opt_list(entry->keyrings);
+ ima_lsm_free_rule(entry);
+ kfree(entry);
+}
+
+static struct ima_rule_entry *ima_lsm_copy_rule(struct ima_rule_entry *entry)
+{
+ struct ima_rule_entry *nentry;
+ int i;
+
+ /*
+ * Immutable elements are copied over as pointers and data; only
+ * lsm rules can change
+ */
+ nentry = kmemdup(entry, sizeof(*nentry), GFP_KERNEL);
+ if (!nentry)
+ return NULL;
+
+ memset(nentry->lsm, 0, sizeof_field(struct ima_rule_entry, lsm));
+
+ for (i = 0; i < MAX_LSM_RULES; i++) {
+ if (!entry->lsm[i].args_p)
+ continue;
+
+ nentry->lsm[i].type = entry->lsm[i].type;
+ nentry->lsm[i].args_p = entry->lsm[i].args_p;
+
+ ima_filter_rule_init(nentry->lsm[i].type, Audit_equal,
+ nentry->lsm[i].args_p,
+ &nentry->lsm[i].rule);
+ if (!nentry->lsm[i].rule)
+ pr_warn("rule for LSM \'%s\' is undefined\n",
+ nentry->lsm[i].args_p);
+ }
+ return nentry;
+}
+
+static int ima_lsm_update_rule(struct ima_rule_entry *entry)
+{
+ int i;
+ struct ima_rule_entry *nentry;
+
+ nentry = ima_lsm_copy_rule(entry);
+ if (!nentry)
+ return -ENOMEM;
+
+ list_replace_rcu(&entry->list, &nentry->list);
+ synchronize_rcu();
+ /*
+ * ima_lsm_copy_rule() shallow copied all references, except for the
+ * LSM references, from entry to nentry so we only want to free the LSM
+ * references and the entry itself. All other memory refrences will now
+ * be owned by nentry.
+ */
+ for (i = 0; i < MAX_LSM_RULES; i++)
+ ima_filter_rule_free(entry->lsm[i].rule);
+ kfree(entry);
+
+ return 0;
+}
+
+static bool ima_rule_contains_lsm_cond(struct ima_rule_entry *entry)
+{
+ int i;
+
+ for (i = 0; i < MAX_LSM_RULES; i++)
+ if (entry->lsm[i].args_p)
+ return true;
+
+ return false;
+}
+
/*
* The LSM policy can be reloaded, leaving the IMA LSM based rules referring
* to the old, stale LSM policy. Update the IMA LSM based rules to reflect
- * the reloaded LSM policy. We assume the rules still exist; and BUG_ON() if
- * they don't.
+ * the reloaded LSM policy.
*/
static void ima_lsm_update_rules(void)
{
- struct ima_rule_entry *entry;
+ struct ima_rule_entry *entry, *e;
int result;
- int i;
- list_for_each_entry(entry, &ima_policy_rules, list) {
- for (i = 0; i < MAX_LSM_RULES; i++) {
- if (!entry->lsm[i].rule)
- continue;
- result = security_filter_rule_init(entry->lsm[i].type,
- Audit_equal,
- entry->lsm[i].args_p,
- &entry->lsm[i].rule);
- BUG_ON(!entry->lsm[i].rule);
+ list_for_each_entry_safe(entry, e, &ima_policy_rules, list) {
+ if (!ima_rule_contains_lsm_cond(entry))
+ continue;
+
+ result = ima_lsm_update_rule(entry);
+ if (result) {
+ pr_err("lsm rule update error %d\n", result);
+ return;
}
}
}
+int ima_lsm_policy_change(struct notifier_block *nb, unsigned long event,
+ void *lsm_data)
+{
+ if (event != LSM_POLICY_CHANGE)
+ return NOTIFY_DONE;
+
+ ima_lsm_update_rules();
+ return NOTIFY_OK;
+}
+
/**
- * ima_match_rules - determine whether an inode matches the measure rule.
+ * ima_match_keyring - determine whether the keyring matches the measure rule
+ * @rule: a pointer to a rule
+ * @keyring: name of the keyring to match against the measure rule
+ * @cred: a pointer to a credentials structure for user validation
+ *
+ * Returns true if keyring matches one in the rule, false otherwise.
+ */
+static bool ima_match_keyring(struct ima_rule_entry *rule,
+ const char *keyring, const struct cred *cred)
+{
+ bool matched = false;
+ size_t i;
+
+ if ((rule->flags & IMA_UID) && !rule->uid_op(cred->uid, rule->uid))
+ return false;
+
+ if (!rule->keyrings)
+ return true;
+
+ if (!keyring)
+ return false;
+
+ for (i = 0; i < rule->keyrings->count; i++) {
+ if (!strcmp(rule->keyrings->items[i], keyring)) {
+ matched = true;
+ break;
+ }
+ }
+
+ return matched;
+}
+
+/**
+ * ima_match_rules - determine whether an inode matches the policy rule.
* @rule: a pointer to a rule
* @inode: a pointer to an inode
* @cred: a pointer to a credentials structure for user validation
* @secid: the secid of the task to be validated
* @func: LIM hook identifier
* @mask: requested action (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC)
+ * @keyring: keyring name to check in policy for KEY_CHECK func
*
* Returns true on rule match, false on failure.
*/
static bool ima_match_rules(struct ima_rule_entry *rule, struct inode *inode,
const struct cred *cred, u32 secid,
- enum ima_hooks func, int mask)
+ enum ima_hooks func, int mask,
+ const char *keyring)
{
int i;
+ bool result = false;
+ struct ima_rule_entry *lsm_rule = rule;
+ bool rule_reinitialized = false;
+ if (func == KEY_CHECK) {
+ return (rule->flags & IMA_FUNC) && (rule->func == func) &&
+ ima_match_keyring(rule, keyring, cred);
+ }
if ((rule->flags & IMA_FUNC) &&
(rule->func != func && func != POST_SETATTR))
return false;
@@ -319,42 +543,56 @@
for (i = 0; i < MAX_LSM_RULES; i++) {
int rc = 0;
u32 osid;
- int retried = 0;
- if (!rule->lsm[i].rule)
- continue;
+ if (!lsm_rule->lsm[i].rule) {
+ if (!lsm_rule->lsm[i].args_p)
+ continue;
+ else
+ return false;
+ }
+
retry:
switch (i) {
case LSM_OBJ_USER:
case LSM_OBJ_ROLE:
case LSM_OBJ_TYPE:
security_inode_getsecid(inode, &osid);
- rc = security_filter_rule_match(osid,
- rule->lsm[i].type,
- Audit_equal,
- rule->lsm[i].rule,
- NULL);
+ rc = ima_filter_rule_match(osid, lsm_rule->lsm[i].type,
+ Audit_equal,
+ lsm_rule->lsm[i].rule);
break;
case LSM_SUBJ_USER:
case LSM_SUBJ_ROLE:
case LSM_SUBJ_TYPE:
- rc = security_filter_rule_match(secid,
- rule->lsm[i].type,
- Audit_equal,
- rule->lsm[i].rule,
- NULL);
+ rc = ima_filter_rule_match(secid, lsm_rule->lsm[i].type,
+ Audit_equal,
+ lsm_rule->lsm[i].rule);
+ break;
default:
break;
}
- if ((rc < 0) && (!retried)) {
- retried = 1;
- ima_lsm_update_rules();
- goto retry;
+
+ if (rc == -ESTALE && !rule_reinitialized) {
+ lsm_rule = ima_lsm_copy_rule(rule);
+ if (lsm_rule) {
+ rule_reinitialized = true;
+ goto retry;
+ }
}
- if (!rc)
- return false;
+ if (!rc) {
+ result = false;
+ goto out;
+ }
}
- return true;
+ result = true;
+
+out:
+ if (rule_reinitialized) {
+ for (i = 0; i < MAX_LSM_RULES; i++)
+ ima_filter_rule_free(lsm_rule->lsm[i].rule);
+ kfree(lsm_rule);
+ }
+ return result;
}
/*
@@ -390,7 +628,11 @@
* @secid: LSM secid of the task to be validated
* @func: IMA hook identifier
* @mask: requested action (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC)
+ * @flags: IMA actions to consider (e.g. IMA_MEASURE | IMA_APPRAISE)
* @pcr: set the pcr to extend
+ * @template_desc: the template that should be used for this rule
+ * @keyring: the keyring name, if given, to be used to check in the policy.
+ * keyring can be NULL if func is anything other than KEY_CHECK.
*
* Measure decision based on func/mask/fsmagic and LSM(subj/obj/type)
* conditions.
@@ -400,10 +642,15 @@
* than writes so ima_match_policy() is classical RCU candidate.
*/
int ima_match_policy(struct inode *inode, const struct cred *cred, u32 secid,
- enum ima_hooks func, int mask, int flags, int *pcr)
+ enum ima_hooks func, int mask, int flags, int *pcr,
+ struct ima_template_desc **template_desc,
+ const char *keyring)
{
struct ima_rule_entry *entry;
int action = 0, actmask = flags | (flags << 1);
+
+ if (template_desc)
+ *template_desc = ima_template_desc_current();
rcu_read_lock();
list_for_each_entry_rcu(entry, ima_rules, list) {
@@ -411,7 +658,8 @@
if (!(entry->action & actmask))
continue;
- if (!ima_match_rules(entry, inode, cred, secid, func, mask))
+ if (!ima_match_rules(entry, inode, cred, secid, func, mask,
+ keyring))
continue;
action |= entry->flags & IMA_ACTION_FLAGS;
@@ -424,6 +672,7 @@
action |= IMA_FAIL_UNVERIFIABLE_SIGS;
}
+
if (entry->action & IMA_DO_MASK)
actmask &= ~(entry->action | entry->action << 1);
else
@@ -431,6 +680,9 @@
if ((pcr) && (entry->flags & IMA_PCR))
*pcr = entry->pcr;
+
+ if (template_desc && entry->template)
+ *template_desc = entry->template;
if (!actmask)
break;
@@ -473,6 +725,79 @@
return 0;
}
+static void add_rules(struct ima_rule_entry *entries, int count,
+ enum policy_rule_list policy_rule)
+{
+ int i = 0;
+
+ for (i = 0; i < count; i++) {
+ struct ima_rule_entry *entry;
+
+ if (policy_rule & IMA_DEFAULT_POLICY)
+ list_add_tail(&entries[i].list, &ima_default_rules);
+
+ if (policy_rule & IMA_CUSTOM_POLICY) {
+ entry = kmemdup(&entries[i], sizeof(*entry),
+ GFP_KERNEL);
+ if (!entry)
+ continue;
+
+ list_add_tail(&entry->list, &ima_policy_rules);
+ }
+ if (entries[i].action == APPRAISE) {
+ if (entries != build_appraise_rules)
+ temp_ima_appraise |=
+ ima_appraise_flag(entries[i].func);
+ else
+ build_ima_appraise |=
+ ima_appraise_flag(entries[i].func);
+ }
+ }
+}
+
+static int ima_parse_rule(char *rule, struct ima_rule_entry *entry);
+
+static int __init ima_init_arch_policy(void)
+{
+ const char * const *arch_rules;
+ const char * const *rules;
+ int arch_entries = 0;
+ int i = 0;
+
+ arch_rules = arch_get_ima_policy();
+ if (!arch_rules)
+ return arch_entries;
+
+ /* Get number of rules */
+ for (rules = arch_rules; *rules != NULL; rules++)
+ arch_entries++;
+
+ arch_policy_entry = kcalloc(arch_entries + 1,
+ sizeof(*arch_policy_entry), GFP_KERNEL);
+ if (!arch_policy_entry)
+ return 0;
+
+ /* Convert each policy string rules to struct ima_rule_entry format */
+ for (rules = arch_rules, i = 0; *rules != NULL; rules++) {
+ char rule[255];
+ int result;
+
+ result = strlcpy(rule, *rules, sizeof(rule));
+
+ INIT_LIST_HEAD(&arch_policy_entry[i].list);
+ result = ima_parse_rule(rule, &arch_policy_entry[i]);
+ if (result) {
+ pr_warn("Skipping unknown architecture policy rule: %s\n",
+ rule);
+ memset(&arch_policy_entry[i], 0,
+ sizeof(*arch_policy_entry));
+ continue;
+ }
+ i++;
+ }
+ return i;
+}
+
/**
* ima_init_policy - initialize the default measure rules.
*
@@ -481,68 +806,69 @@
*/
void __init ima_init_policy(void)
{
- int i, measure_entries, appraise_entries, secure_boot_entries;
+ int build_appraise_entries, arch_entries;
- /* if !ima_policy set entries = 0 so we load NO default rules */
- measure_entries = ima_policy ? ARRAY_SIZE(dont_measure_rules) : 0;
- appraise_entries = ima_use_appraise_tcb ?
- ARRAY_SIZE(default_appraise_rules) : 0;
- secure_boot_entries = ima_use_secure_boot ?
- ARRAY_SIZE(secure_boot_rules) : 0;
-
- for (i = 0; i < measure_entries; i++)
- list_add_tail(&dont_measure_rules[i].list, &ima_default_rules);
+ /* if !ima_policy, we load NO default rules */
+ if (ima_policy)
+ add_rules(dont_measure_rules, ARRAY_SIZE(dont_measure_rules),
+ IMA_DEFAULT_POLICY);
switch (ima_policy) {
case ORIGINAL_TCB:
- for (i = 0; i < ARRAY_SIZE(original_measurement_rules); i++)
- list_add_tail(&original_measurement_rules[i].list,
- &ima_default_rules);
+ add_rules(original_measurement_rules,
+ ARRAY_SIZE(original_measurement_rules),
+ IMA_DEFAULT_POLICY);
break;
case DEFAULT_TCB:
- for (i = 0; i < ARRAY_SIZE(default_measurement_rules); i++)
- list_add_tail(&default_measurement_rules[i].list,
- &ima_default_rules);
+ add_rules(default_measurement_rules,
+ ARRAY_SIZE(default_measurement_rules),
+ IMA_DEFAULT_POLICY);
+ break;
default:
break;
}
/*
- * Insert the builtin "secure_boot" policy rules requiring file
- * signatures, prior to any other appraise rules.
+ * Based on runtime secure boot flags, insert arch specific measurement
+ * and appraise rules requiring file signatures for both the initial
+ * and custom policies, prior to other appraise rules.
+ * (Highest priority)
*/
- for (i = 0; i < secure_boot_entries; i++) {
- list_add_tail(&secure_boot_rules[i].list, &ima_default_rules);
- temp_ima_appraise |=
- ima_appraise_flag(secure_boot_rules[i].func);
- }
+ arch_entries = ima_init_arch_policy();
+ if (!arch_entries)
+ pr_info("No architecture policies found\n");
+ else
+ add_rules(arch_policy_entry, arch_entries,
+ IMA_DEFAULT_POLICY | IMA_CUSTOM_POLICY);
+
+ /*
+ * Insert the builtin "secure_boot" policy rules requiring file
+ * signatures, prior to other appraise rules.
+ */
+ if (ima_use_secure_boot)
+ add_rules(secure_boot_rules, ARRAY_SIZE(secure_boot_rules),
+ IMA_DEFAULT_POLICY);
/*
* Insert the build time appraise rules requiring file signatures
* for both the initial and custom policies, prior to other appraise
- * rules.
+ * rules. As the secure boot rules includes all of the build time
+ * rules, include either one or the other set of rules, but not both.
*/
- for (i = 0; i < ARRAY_SIZE(build_appraise_rules); i++) {
- struct ima_rule_entry *entry;
-
- if (!secure_boot_entries)
- list_add_tail(&build_appraise_rules[i].list,
- &ima_default_rules);
-
- entry = kmemdup(&build_appraise_rules[i], sizeof(*entry),
- GFP_KERNEL);
- if (entry)
- list_add_tail(&entry->list, &ima_policy_rules);
- build_ima_appraise |=
- ima_appraise_flag(build_appraise_rules[i].func);
+ build_appraise_entries = ARRAY_SIZE(build_appraise_rules);
+ if (build_appraise_entries) {
+ if (ima_use_secure_boot)
+ add_rules(build_appraise_rules, build_appraise_entries,
+ IMA_CUSTOM_POLICY);
+ else
+ add_rules(build_appraise_rules, build_appraise_entries,
+ IMA_DEFAULT_POLICY | IMA_CUSTOM_POLICY);
}
- for (i = 0; i < appraise_entries; i++) {
- list_add_tail(&default_appraise_rules[i].list,
- &ima_default_rules);
- if (default_appraise_rules[i].func == POLICY_CHECK)
- temp_ima_appraise |= IMA_APPRAISE_POLICY;
- }
+ if (ima_use_appraise_tcb)
+ add_rules(default_appraise_rules,
+ ARRAY_SIZE(default_appraise_rules),
+ IMA_DEFAULT_POLICY);
ima_update_policy_flag();
}
@@ -575,13 +901,24 @@
if (ima_rules != policy) {
ima_policy_flag = 0;
ima_rules = policy;
+
+ /*
+ * IMA architecture specific policy rules are specified
+ * as strings and converted to an array of ima_entry_rules
+ * on boot. After loading a custom policy, free the
+ * architecture specific rules stored as an array.
+ */
+ kfree(arch_policy_entry);
}
ima_update_policy_flag();
+
+ /* Custom IMA policy has been loaded */
+ ima_process_queued_keys();
}
+/* Keep the enumeration in sync with the policy_tokens! */
enum {
- Opt_err = -1,
- Opt_measure = 1, Opt_dont_measure,
+ Opt_measure, Opt_dont_measure,
Opt_appraise, Opt_dont_appraise,
Opt_audit, Opt_hash, Opt_dont_hash,
Opt_obj_user, Opt_obj_role, Opt_obj_type,
@@ -590,11 +927,12 @@
Opt_fsuuid, Opt_uid_eq, Opt_euid_eq, Opt_fowner_eq,
Opt_uid_gt, Opt_euid_gt, Opt_fowner_gt,
Opt_uid_lt, Opt_euid_lt, Opt_fowner_lt,
- Opt_appraise_type, Opt_permit_directio,
- Opt_pcr
+ Opt_appraise_type, Opt_appraise_flag,
+ Opt_permit_directio, Opt_pcr, Opt_template, Opt_keyrings,
+ Opt_err
};
-static match_table_t policy_tokens = {
+static const match_table_t policy_tokens = {
{Opt_measure, "measure"},
{Opt_dont_measure, "dont_measure"},
{Opt_appraise, "appraise"},
@@ -623,8 +961,11 @@
{Opt_euid_lt, "euid<%s"},
{Opt_fowner_lt, "fowner<%s"},
{Opt_appraise_type, "appraise_type=%s"},
+ {Opt_appraise_flag, "appraise_flag=%s"},
{Opt_permit_directio, "permit_directio"},
{Opt_pcr, "pcr=%s"},
+ {Opt_template, "template=%s"},
+ {Opt_keyrings, "keyrings=%s"},
{Opt_err, NULL}
};
@@ -641,13 +982,19 @@
return -ENOMEM;
entry->lsm[lsm_rule].type = audit_type;
- result = security_filter_rule_init(entry->lsm[lsm_rule].type,
- Audit_equal,
- entry->lsm[lsm_rule].args_p,
- &entry->lsm[lsm_rule].rule);
+ result = ima_filter_rule_init(entry->lsm[lsm_rule].type, Audit_equal,
+ entry->lsm[lsm_rule].args_p,
+ &entry->lsm[lsm_rule].rule);
if (!entry->lsm[lsm_rule].rule) {
- kfree(entry->lsm[lsm_rule].args_p);
- return -EINVAL;
+ pr_warn("rule for LSM \'%s\' is undefined\n",
+ entry->lsm[lsm_rule].args_p);
+
+ if (ima_rules == &ima_default_rules) {
+ kfree(entry->lsm[lsm_rule].args_p);
+ entry->lsm[lsm_rule].args_p = NULL;
+ result = -EINVAL;
+ } else
+ result = 0;
}
return result;
@@ -672,12 +1019,135 @@
ima_log_string_op(ab, key, value, NULL);
}
+/*
+ * Validating the appended signature included in the measurement list requires
+ * the file hash calculated without the appended signature (i.e., the 'd-modsig'
+ * field). Therefore, notify the user if they have the 'modsig' field but not
+ * the 'd-modsig' field in the template.
+ */
+static void check_template_modsig(const struct ima_template_desc *template)
+{
+#define MSG "template with 'modsig' field also needs 'd-modsig' field\n"
+ bool has_modsig, has_dmodsig;
+ static bool checked;
+ int i;
+
+ /* We only need to notify the user once. */
+ if (checked)
+ return;
+
+ has_modsig = has_dmodsig = false;
+ for (i = 0; i < template->num_fields; i++) {
+ if (!strcmp(template->fields[i]->field_id, "modsig"))
+ has_modsig = true;
+ else if (!strcmp(template->fields[i]->field_id, "d-modsig"))
+ has_dmodsig = true;
+ }
+
+ if (has_modsig && !has_dmodsig)
+ pr_notice(MSG);
+
+ checked = true;
+#undef MSG
+}
+
+static bool ima_validate_rule(struct ima_rule_entry *entry)
+{
+ /* Ensure that the action is set and is compatible with the flags */
+ if (entry->action == UNKNOWN)
+ return false;
+
+ if (entry->action != MEASURE && entry->flags & IMA_PCR)
+ return false;
+
+ if (entry->action != APPRAISE &&
+ entry->flags & (IMA_DIGSIG_REQUIRED | IMA_MODSIG_ALLOWED | IMA_CHECK_BLACKLIST))
+ return false;
+
+ /*
+ * The IMA_FUNC bit must be set if and only if there's a valid hook
+ * function specified, and vice versa. Enforcing this property allows
+ * for the NONE case below to validate a rule without an explicit hook
+ * function.
+ */
+ if (((entry->flags & IMA_FUNC) && entry->func == NONE) ||
+ (!(entry->flags & IMA_FUNC) && entry->func != NONE))
+ return false;
+
+ /*
+ * Ensure that the hook function is compatible with the other
+ * components of the rule
+ */
+ switch (entry->func) {
+ case NONE:
+ case FILE_CHECK:
+ case MMAP_CHECK:
+ case BPRM_CHECK:
+ case CREDS_CHECK:
+ case POST_SETATTR:
+ case FIRMWARE_CHECK:
+ case POLICY_CHECK:
+ if (entry->flags & ~(IMA_FUNC | IMA_MASK | IMA_FSMAGIC |
+ IMA_UID | IMA_FOWNER | IMA_FSUUID |
+ IMA_INMASK | IMA_EUID | IMA_PCR |
+ IMA_FSNAME | IMA_DIGSIG_REQUIRED |
+ IMA_PERMIT_DIRECTIO))
+ return false;
+
+ break;
+ case MODULE_CHECK:
+ case KEXEC_KERNEL_CHECK:
+ case KEXEC_INITRAMFS_CHECK:
+ if (entry->flags & ~(IMA_FUNC | IMA_MASK | IMA_FSMAGIC |
+ IMA_UID | IMA_FOWNER | IMA_FSUUID |
+ IMA_INMASK | IMA_EUID | IMA_PCR |
+ IMA_FSNAME | IMA_DIGSIG_REQUIRED |
+ IMA_PERMIT_DIRECTIO | IMA_MODSIG_ALLOWED |
+ IMA_CHECK_BLACKLIST))
+ return false;
+
+ break;
+ case KEXEC_CMDLINE:
+ if (entry->action & ~(MEASURE | DONT_MEASURE))
+ return false;
+
+ if (entry->flags & ~(IMA_FUNC | IMA_FSMAGIC | IMA_UID |
+ IMA_FOWNER | IMA_FSUUID | IMA_EUID |
+ IMA_PCR | IMA_FSNAME))
+ return false;
+
+ break;
+ case KEY_CHECK:
+ if (entry->action & ~(MEASURE | DONT_MEASURE))
+ return false;
+
+ if (entry->flags & ~(IMA_FUNC | IMA_UID | IMA_PCR |
+ IMA_KEYRINGS))
+ return false;
+
+ if (ima_rule_contains_lsm_cond(entry))
+ return false;
+
+ break;
+ default:
+ return false;
+ }
+
+ /* Ensure that combinations of flags are compatible with each other */
+ if (entry->flags & IMA_CHECK_BLACKLIST &&
+ !(entry->flags & IMA_MODSIG_ALLOWED))
+ return false;
+
+ return true;
+}
+
static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
{
struct audit_buffer *ab;
char *from;
char *p;
bool uid_token;
+ struct ima_template_desc *template_desc;
int result = 0;
ab = integrity_audit_log_start(audit_context(), GFP_KERNEL,
@@ -785,6 +1255,11 @@
entry->func = KEXEC_INITRAMFS_CHECK;
else if (strcmp(args[0].from, "POLICY_CHECK") == 0)
entry->func = POLICY_CHECK;
+ else if (strcmp(args[0].from, "KEXEC_CMDLINE") == 0)
+ entry->func = KEXEC_CMDLINE;
+ else if (IS_ENABLED(CONFIG_IMA_MEASURE_ASYMMETRIC_KEYS) &&
+ strcmp(args[0].from, "KEY_CHECK") == 0)
+ entry->func = KEY_CHECK;
else
result = -EINVAL;
if (!result)
@@ -837,6 +1312,24 @@
result = 0;
entry->flags |= IMA_FSNAME;
break;
+ case Opt_keyrings:
+ ima_log_string(ab, "keyrings", args[0].from);
+
+ if (!IS_ENABLED(CONFIG_IMA_MEASURE_ASYMMETRIC_KEYS) ||
+ entry->keyrings) {
+ result = -EINVAL;
+ break;
+ }
+
+ entry->keyrings = ima_alloc_rule_opt_list(args);
+ if (IS_ERR(entry->keyrings)) {
+ result = PTR_ERR(entry->keyrings);
+ entry->keyrings = NULL;
+ break;
+ }
+
+ entry->flags |= IMA_KEYRINGS;
+ break;
case Opt_fsuuid:
ima_log_string(ab, "fsuuid", args[0].from);
@@ -852,10 +1345,12 @@
case Opt_uid_gt:
case Opt_euid_gt:
entry->uid_op = &uid_gt;
+ fallthrough;
case Opt_uid_lt:
case Opt_euid_lt:
if ((token == Opt_uid_lt) || (token == Opt_euid_lt))
entry->uid_op = &uid_lt;
+ fallthrough;
case Opt_uid_eq:
case Opt_euid_eq:
uid_token = (token == Opt_uid_eq) ||
@@ -884,9 +1379,11 @@
break;
case Opt_fowner_gt:
entry->fowner_op = &uid_gt;
+ fallthrough;
case Opt_fowner_lt:
if (token == Opt_fowner_lt)
entry->fowner_op = &uid_lt;
+ fallthrough;
case Opt_fowner_eq:
ima_log_string_op(ab, "fowner", args[0].from,
entry->fowner_op);
@@ -942,14 +1439,21 @@
AUDIT_SUBJ_TYPE);
break;
case Opt_appraise_type:
- if (entry->action != APPRAISE) {
- result = -EINVAL;
- break;
- }
-
ima_log_string(ab, "appraise_type", args[0].from);
if ((strcmp(args[0].from, "imasig")) == 0)
entry->flags |= IMA_DIGSIG_REQUIRED;
+ else if (IS_ENABLED(CONFIG_IMA_APPRAISE_MODSIG) &&
+ strcmp(args[0].from, "imasig|modsig") == 0)
+ entry->flags |= IMA_DIGSIG_REQUIRED |
+ IMA_MODSIG_ALLOWED;
+ else
+ result = -EINVAL;
+ break;
+ case Opt_appraise_flag:
+ ima_log_string(ab, "appraise_flag", args[0].from);
+ if (IS_ENABLED(CONFIG_IMA_APPRAISE_MODSIG) &&
+ strstr(args[0].from, "blacklist"))
+ entry->flags |= IMA_CHECK_BLACKLIST;
else
result = -EINVAL;
break;
@@ -957,10 +1461,6 @@
entry->flags |= IMA_PERMIT_DIRECTIO;
break;
case Opt_pcr:
- if (entry->action != MEASURE) {
- result = -EINVAL;
- break;
- }
ima_log_string(ab, "pcr", args[0].from);
result = kstrtoint(args[0].from, 10, &entry->pcr);
@@ -970,16 +1470,44 @@
entry->flags |= IMA_PCR;
break;
+ case Opt_template:
+ ima_log_string(ab, "template", args[0].from);
+ if (entry->action != MEASURE) {
+ result = -EINVAL;
+ break;
+ }
+ template_desc = lookup_template_desc(args[0].from);
+ if (!template_desc || entry->template) {
+ result = -EINVAL;
+ break;
+ }
+
+ /*
+ * template_desc_init_fields() does nothing if
+ * the template is already initialised, so
+ * it's safe to do this unconditionally
+ */
+ template_desc_init_fields(template_desc->fmt,
+ &(template_desc->fields),
+ &(template_desc->num_fields));
+ entry->template = template_desc;
+ break;
case Opt_err:
ima_log_string(ab, "UNKNOWN", p);
result = -EINVAL;
break;
}
}
- if (!result && (entry->action == UNKNOWN))
+ if (!result && !ima_validate_rule(entry))
result = -EINVAL;
else if (entry->action == APPRAISE)
temp_ima_appraise |= ima_appraise_flag(entry->func);
+
+ if (!result && entry->flags & IMA_MODSIG_ALLOWED) {
+ template_desc = entry->template ? entry->template :
+ ima_template_desc_current();
+ check_template_modsig(template_desc);
+ }
audit_log_format(ab, "res=%d", !result);
audit_log_end(ab);
@@ -988,7 +1516,7 @@
/**
* ima_parse_add_rule - add a rule to ima_policy_rules
- * @rule - ima measurement policy rule
+ * @rule: ima measurement policy rule
*
* Avoid locking by allowing just one writer at a time in ima_write_policy()
* Returns the length of the rule parsed, an error code on failure
@@ -1019,7 +1547,7 @@
result = ima_parse_rule(p, entry);
if (result) {
- kfree(entry);
+ ima_free_rule(entry);
integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL,
NULL, op, "invalid-policy", result,
audit_info);
@@ -1040,17 +1568,19 @@
void ima_delete_rules(void)
{
struct ima_rule_entry *entry, *tmp;
- int i;
temp_ima_appraise = 0;
list_for_each_entry_safe(entry, tmp, &ima_temp_rules, list) {
- for (i = 0; i < MAX_LSM_RULES; i++)
- kfree(entry->lsm[i].args_p);
-
list_del(&entry->list);
- kfree(entry);
+ ima_free_rule(entry);
}
}
+
+#define __ima_hook_stringify(func, str) (#func),
+
+const char *const func_tokens[] = {
+ __ima_hooks(__ima_hook_stringify)
+};
#ifdef CONFIG_IMA_READ_POLICY
enum {
@@ -1062,12 +1592,6 @@
"^MAY_WRITE",
"^MAY_READ",
"^MAY_APPEND"
-};
-
-#define __ima_hook_stringify(str) (#str),
-
-static const char *const func_tokens[] = {
- __ima_hooks(__ima_hook_stringify)
};
void *ima_policy_start(struct seq_file *m, loff_t *pos)
@@ -1102,7 +1626,7 @@
{
}
-#define pt(token) policy_tokens[token + Opt_err].pattern
+#define pt(token) policy_tokens[token].pattern
#define mt(token) mask_tokens[token]
/*
@@ -1116,6 +1640,15 @@
seq_printf(m, "func=%d ", func);
}
+static void ima_show_rule_opt_list(struct seq_file *m,
+ const struct ima_rule_opt_list *opt_list)
+{
+ size_t i;
+
+ for (i = 0; i < opt_list->count; i++)
+ seq_printf(m, "%s%s", i ? "|" : "", opt_list->items[i]);
+}
+
int ima_policy_show(struct seq_file *m, void *v)
{
struct ima_rule_entry *entry = v;
@@ -1124,6 +1657,14 @@
int offset = 0;
rcu_read_lock();
+
+ /* Do not print rules with inactive LSM labels */
+ for (i = 0; i < MAX_LSM_RULES; i++) {
+ if (entry->lsm[i].args_p && !entry->lsm[i].rule) {
+ rcu_read_unlock();
+ return 0;
+ }
+ }
if (entry->action & MEASURE)
seq_puts(m, pt(Opt_measure));
@@ -1168,6 +1709,12 @@
if (entry->flags & IMA_FSNAME) {
snprintf(tbuf, sizeof(tbuf), "%s", entry->fsname);
seq_printf(m, pt(Opt_fsname), tbuf);
+ seq_puts(m, " ");
+ }
+
+ if (entry->flags & IMA_KEYRINGS) {
+ seq_puts(m, "keyrings=");
+ ima_show_rule_opt_list(m, entry->keyrings);
seq_puts(m, " ");
}
@@ -1220,33 +1767,42 @@
switch (i) {
case LSM_OBJ_USER:
seq_printf(m, pt(Opt_obj_user),
- (char *)entry->lsm[i].args_p);
+ entry->lsm[i].args_p);
break;
case LSM_OBJ_ROLE:
seq_printf(m, pt(Opt_obj_role),
- (char *)entry->lsm[i].args_p);
+ entry->lsm[i].args_p);
break;
case LSM_OBJ_TYPE:
seq_printf(m, pt(Opt_obj_type),
- (char *)entry->lsm[i].args_p);
+ entry->lsm[i].args_p);
break;
case LSM_SUBJ_USER:
seq_printf(m, pt(Opt_subj_user),
- (char *)entry->lsm[i].args_p);
+ entry->lsm[i].args_p);
break;
case LSM_SUBJ_ROLE:
seq_printf(m, pt(Opt_subj_role),
- (char *)entry->lsm[i].args_p);
+ entry->lsm[i].args_p);
break;
case LSM_SUBJ_TYPE:
seq_printf(m, pt(Opt_subj_type),
- (char *)entry->lsm[i].args_p);
+ entry->lsm[i].args_p);
break;
}
+ seq_puts(m, " ");
}
}
- if (entry->flags & IMA_DIGSIG_REQUIRED)
- seq_puts(m, "appraise_type=imasig ");
+ if (entry->template)
+ seq_printf(m, "template=%s ", entry->template->name);
+ if (entry->flags & IMA_DIGSIG_REQUIRED) {
+ if (entry->flags & IMA_MODSIG_ALLOWED)
+ seq_puts(m, "appraise_type=imasig|modsig ");
+ else
+ seq_puts(m, "appraise_type=imasig ");
+ }
+ if (entry->flags & IMA_CHECK_BLACKLIST)
+ seq_puts(m, "appraise_flag=check_blacklist ");
if (entry->flags & IMA_PERMIT_DIRECTIO)
seq_puts(m, "permit_directio ");
rcu_read_unlock();
@@ -1254,3 +1810,57 @@
return 0;
}
#endif /* CONFIG_IMA_READ_POLICY */
+
+#if defined(CONFIG_IMA_APPRAISE) && defined(CONFIG_INTEGRITY_TRUSTED_KEYRING)
+/*
+ * ima_appraise_signature: whether IMA will appraise a given function using
+ * an IMA digital signature. This is restricted to cases where the kernel
+ * has a set of built-in trusted keys in order to avoid an attacker simply
+ * loading additional keys.
+ */
+bool ima_appraise_signature(enum kernel_read_file_id id)
+{
+ struct ima_rule_entry *entry;
+ bool found = false;
+ enum ima_hooks func;
+
+ if (id >= READING_MAX_ID)
+ return false;
+
+ if (id == READING_KEXEC_IMAGE && !(ima_appraise & IMA_APPRAISE_ENFORCE)
+ && security_locked_down(LOCKDOWN_KEXEC))
+ return false;
+
+ func = read_idmap[id] ?: FILE_CHECK;
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(entry, ima_rules, list) {
+ if (entry->action != APPRAISE)
+ continue;
+
+ /*
+ * A generic entry will match, but otherwise require that it
+ * match the func we're looking for
+ */
+ if (entry->func && entry->func != func)
+ continue;
+
+ /*
+ * We require this to be a digital signature, not a raw IMA
+ * hash.
+ */
+ if (entry->flags & IMA_DIGSIG_REQUIRED)
+ found = true;
+
+ /*
+ * We've found a rule that matches, so break now even if it
+ * didn't require a digital signature - a later rule that does
+ * won't override it, so would be a false positive.
+ */
+ break;
+ }
+
+ rcu_read_unlock();
+ return found;
+}
+#endif /* CONFIG_IMA_APPRAISE && CONFIG_INTEGRITY_TRUSTED_KEYRING */
--
Gitblit v1.6.2