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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-27 10:05:51 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-27 10:05:51 +0000
commit5d1646d90e1f2cceb9f0828f4b28318cd0ec7744 (patch)
treea94efe259b9009378be6d90eb30d2b019d95c194 /security/integrity/ima/ima_policy.c
parentInitial commit. (diff)
downloadlinux-5d1646d90e1f2cceb9f0828f4b28318cd0ec7744.tar.xz
linux-5d1646d90e1f2cceb9f0828f4b28318cd0ec7744.zip
Adding upstream version 5.10.209.upstream/5.10.209upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'security/integrity/ima/ima_policy.c')
-rw-r--r--security/integrity/ima/ima_policy.c1866
1 files changed, 1866 insertions, 0 deletions
diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
new file mode 100644
index 000000000..1c403e8a8
--- /dev/null
+++ b/security/integrity/ima/ima_policy.c
@@ -0,0 +1,1866 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2008 IBM Corporation
+ * Author: Mimi Zohar <zohar@us.ibm.com>
+ *
+ * ima_policy.c
+ * - initialize default measure policy rules
+ */
+
+#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>
+#include <linux/parser.h>
+#include <linux/slab.h>
+#include <linux/rculist.h>
+#include <linux/genhd.h>
+#include <linux/seq_file.h>
+#include <linux/ima.h>
+
+#include "ima.h"
+
+/* flags definitions */
+#define IMA_FUNC 0x0001
+#define IMA_MASK 0x0002
+#define IMA_FSMAGIC 0x0004
+#define IMA_UID 0x0008
+#define IMA_FOWNER 0x0010
+#define IMA_FSUUID 0x0020
+#define IMA_INMASK 0x0040
+#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 */
+#define DONT_MEASURE 0x0002
+#define APPRAISE 0x0004 /* same as IMA_APPRAISE */
+#define DONT_APPRAISE 0x0008
+#define AUDIT 0x0040
+#define HASH 0x0100
+#define DONT_HASH 0x0200
+
+#define INVALID_PCR(a) (((a) < 0) || \
+ (a) >= (sizeof_field(struct integrity_iint_cache, measured_pcrs) * 8))
+
+int ima_policy_flag;
+static int temp_ima_appraise;
+static int build_ima_appraise __ro_after_init;
+
+#define MAX_LSM_RULES 6
+enum lsm_rule_types { LSM_OBJ_USER, LSM_OBJ_ROLE, LSM_OBJ_TYPE,
+ LSM_SUBJ_USER, LSM_SUBJ_ROLE, LSM_SUBJ_TYPE
+};
+
+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;
+ int action;
+ unsigned int flags;
+ enum ima_hooks func;
+ int mask;
+ unsigned long fsmagic;
+ uuid_t fsuuid;
+ kuid_t uid;
+ kuid_t fowner;
+ bool (*uid_op)(kuid_t, kuid_t); /* Handlers for operators */
+ bool (*fowner_op)(kuid_t, kuid_t); /* uid_eq(), uid_gt(), uid_lt() */
+ int pcr;
+ struct {
+ void *rule; /* LSM file metadata specific */
+ 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;
+};
+
+/*
+ * Without LSM specific knowledge, the default policy can only be
+ * written in terms of .action, .func, .mask, .fsmagic, .uid, and .fowner
+ */
+
+/*
+ * The minimum rule set to allow for full TCB coverage. Measures all files
+ * opened or mmap for exec and everything read by root. Dangerous because
+ * normal users can easily run the machine out of memory simply building
+ * and running executables.
+ */
+static struct ima_rule_entry dont_measure_rules[] __ro_after_init = {
+ {.action = DONT_MEASURE, .fsmagic = PROC_SUPER_MAGIC, .flags = IMA_FSMAGIC},
+ {.action = DONT_MEASURE, .fsmagic = SYSFS_MAGIC, .flags = IMA_FSMAGIC},
+ {.action = DONT_MEASURE, .fsmagic = DEBUGFS_MAGIC, .flags = IMA_FSMAGIC},
+ {.action = DONT_MEASURE, .fsmagic = TMPFS_MAGIC, .flags = IMA_FSMAGIC},
+ {.action = DONT_MEASURE, .fsmagic = DEVPTS_SUPER_MAGIC, .flags = IMA_FSMAGIC},
+ {.action = DONT_MEASURE, .fsmagic = BINFMTFS_MAGIC, .flags = IMA_FSMAGIC},
+ {.action = DONT_MEASURE, .fsmagic = SECURITYFS_MAGIC, .flags = IMA_FSMAGIC},
+ {.action = DONT_MEASURE, .fsmagic = SELINUX_MAGIC, .flags = IMA_FSMAGIC},
+ {.action = DONT_MEASURE, .fsmagic = SMACK_MAGIC, .flags = IMA_FSMAGIC},
+ {.action = DONT_MEASURE, .fsmagic = CGROUP_SUPER_MAGIC,
+ .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 = EFIVARFS_MAGIC, .flags = IMA_FSMAGIC}
+};
+
+static struct ima_rule_entry original_measurement_rules[] __ro_after_init = {
+ {.action = MEASURE, .func = MMAP_CHECK, .mask = MAY_EXEC,
+ .flags = IMA_FUNC | IMA_MASK},
+ {.action = MEASURE, .func = BPRM_CHECK, .mask = MAY_EXEC,
+ .flags = IMA_FUNC | IMA_MASK},
+ {.action = MEASURE, .func = FILE_CHECK, .mask = MAY_READ,
+ .uid = GLOBAL_ROOT_UID, .uid_op = &uid_eq,
+ .flags = IMA_FUNC | IMA_MASK | IMA_UID},
+ {.action = MEASURE, .func = MODULE_CHECK, .flags = IMA_FUNC},
+ {.action = MEASURE, .func = FIRMWARE_CHECK, .flags = IMA_FUNC},
+};
+
+static struct ima_rule_entry default_measurement_rules[] __ro_after_init = {
+ {.action = MEASURE, .func = MMAP_CHECK, .mask = MAY_EXEC,
+ .flags = IMA_FUNC | IMA_MASK},
+ {.action = MEASURE, .func = BPRM_CHECK, .mask = MAY_EXEC,
+ .flags = IMA_FUNC | IMA_MASK},
+ {.action = MEASURE, .func = FILE_CHECK, .mask = MAY_READ,
+ .uid = GLOBAL_ROOT_UID, .uid_op = &uid_eq,
+ .flags = IMA_FUNC | IMA_INMASK | IMA_EUID},
+ {.action = MEASURE, .func = FILE_CHECK, .mask = MAY_READ,
+ .uid = GLOBAL_ROOT_UID, .uid_op = &uid_eq,
+ .flags = IMA_FUNC | IMA_INMASK | IMA_UID},
+ {.action = MEASURE, .func = MODULE_CHECK, .flags = IMA_FUNC},
+ {.action = MEASURE, .func = FIRMWARE_CHECK, .flags = IMA_FUNC},
+ {.action = MEASURE, .func = POLICY_CHECK, .flags = IMA_FUNC},
+};
+
+static struct ima_rule_entry default_appraise_rules[] __ro_after_init = {
+ {.action = DONT_APPRAISE, .fsmagic = PROC_SUPER_MAGIC, .flags = IMA_FSMAGIC},
+ {.action = DONT_APPRAISE, .fsmagic = SYSFS_MAGIC, .flags = IMA_FSMAGIC},
+ {.action = DONT_APPRAISE, .fsmagic = DEBUGFS_MAGIC, .flags = IMA_FSMAGIC},
+ {.action = DONT_APPRAISE, .fsmagic = TMPFS_MAGIC, .flags = IMA_FSMAGIC},
+ {.action = DONT_APPRAISE, .fsmagic = RAMFS_MAGIC, .flags = IMA_FSMAGIC},
+ {.action = DONT_APPRAISE, .fsmagic = DEVPTS_SUPER_MAGIC, .flags = IMA_FSMAGIC},
+ {.action = DONT_APPRAISE, .fsmagic = BINFMTFS_MAGIC, .flags = IMA_FSMAGIC},
+ {.action = DONT_APPRAISE, .fsmagic = SECURITYFS_MAGIC, .flags = IMA_FSMAGIC},
+ {.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
+ {.action = APPRAISE, .func = POLICY_CHECK,
+ .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
+#endif
+#ifndef CONFIG_IMA_APPRAISE_SIGNED_INIT
+ {.action = APPRAISE, .fowner = GLOBAL_ROOT_UID, .fowner_op = &uid_eq,
+ .flags = IMA_FOWNER},
+#else
+ /* force signature */
+ {.action = APPRAISE, .fowner = GLOBAL_ROOT_UID, .fowner_op = &uid_eq,
+ .flags = IMA_FOWNER | IMA_DIGSIG_REQUIRED},
+#endif
+};
+
+static struct ima_rule_entry build_appraise_rules[] __ro_after_init = {
+#ifdef CONFIG_IMA_APPRAISE_REQUIRE_MODULE_SIGS
+ {.action = APPRAISE, .func = MODULE_CHECK,
+ .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
+#endif
+#ifdef CONFIG_IMA_APPRAISE_REQUIRE_FIRMWARE_SIGS
+ {.action = APPRAISE, .func = FIRMWARE_CHECK,
+ .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
+#endif
+#ifdef CONFIG_IMA_APPRAISE_REQUIRE_KEXEC_SIGS
+ {.action = APPRAISE, .func = KEXEC_KERNEL_CHECK,
+ .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
+#endif
+#ifdef CONFIG_IMA_APPRAISE_REQUIRE_POLICY_SIGS
+ {.action = APPRAISE, .func = POLICY_CHECK,
+ .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
+#endif
+};
+
+static struct ima_rule_entry secure_boot_rules[] __ro_after_init = {
+ {.action = APPRAISE, .func = MODULE_CHECK,
+ .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
+ {.action = APPRAISE, .func = FIRMWARE_CHECK,
+ .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
+ {.action = APPRAISE, .func = KEXEC_KERNEL_CHECK,
+ .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
+ {.action = APPRAISE, .func = POLICY_CHECK,
+ .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);
+static struct list_head *ima_rules = &ima_default_rules;
+
+static int ima_policy __initdata;
+
+static int __init default_measure_policy_setup(char *str)
+{
+ if (ima_policy)
+ return 1;
+
+ ima_policy = ORIGINAL_TCB;
+ return 1;
+}
+__setup("ima_tcb", default_measure_policy_setup);
+
+static bool ima_use_appraise_tcb __initdata;
+static bool ima_use_secure_boot __initdata;
+static bool ima_fail_unverifiable_sigs __ro_after_init;
+static int __init policy_setup(char *str)
+{
+ char *p;
+
+ while ((p = strsep(&str, " |\n")) != NULL) {
+ if (*p == ' ')
+ continue;
+ if ((strcmp(p, "tcb") == 0) && !ima_policy)
+ ima_policy = DEFAULT_TCB;
+ else if (strcmp(p, "appraise_tcb") == 0)
+ ima_use_appraise_tcb = true;
+ else if (strcmp(p, "secure_boot") == 0)
+ 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;
+}
+__setup("ima_policy=", policy_setup);
+
+static int __init default_appraise_policy_setup(char *str)
+{
+ ima_use_appraise_tcb = true;
+ return 1;
+}
+__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.
+ */
+static void ima_lsm_update_rules(void)
+{
+ struct ima_rule_entry *entry, *e;
+ int result;
+
+ 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_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,
+ 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;
+ if ((rule->flags & IMA_MASK) &&
+ (rule->mask != mask && func != POST_SETATTR))
+ return false;
+ if ((rule->flags & IMA_INMASK) &&
+ (!(rule->mask & mask) && func != POST_SETATTR))
+ return false;
+ if ((rule->flags & IMA_FSMAGIC)
+ && rule->fsmagic != inode->i_sb->s_magic)
+ return false;
+ if ((rule->flags & IMA_FSNAME)
+ && strcmp(rule->fsname, inode->i_sb->s_type->name))
+ return false;
+ if ((rule->flags & IMA_FSUUID) &&
+ !uuid_equal(&rule->fsuuid, &inode->i_sb->s_uuid))
+ return false;
+ if ((rule->flags & IMA_UID) && !rule->uid_op(cred->uid, rule->uid))
+ return false;
+ if (rule->flags & IMA_EUID) {
+ if (has_capability_noaudit(current, CAP_SETUID)) {
+ if (!rule->uid_op(cred->euid, rule->uid)
+ && !rule->uid_op(cred->suid, rule->uid)
+ && !rule->uid_op(cred->uid, rule->uid))
+ return false;
+ } else if (!rule->uid_op(cred->euid, rule->uid))
+ return false;
+ }
+
+ if ((rule->flags & IMA_FOWNER) &&
+ !rule->fowner_op(inode->i_uid, rule->fowner))
+ return false;
+ for (i = 0; i < MAX_LSM_RULES; i++) {
+ int rc = 0;
+ u32 osid;
+
+ 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 = 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 = ima_filter_rule_match(secid, lsm_rule->lsm[i].type,
+ Audit_equal,
+ lsm_rule->lsm[i].rule);
+ break;
+ default:
+ break;
+ }
+
+ if (rc == -ESTALE && !rule_reinitialized) {
+ lsm_rule = ima_lsm_copy_rule(rule);
+ if (lsm_rule) {
+ rule_reinitialized = true;
+ goto retry;
+ }
+ }
+ if (!rc) {
+ result = false;
+ goto out;
+ }
+ }
+ 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;
+}
+
+/*
+ * In addition to knowing that we need to appraise the file in general,
+ * we need to differentiate between calling hooks, for hook specific rules.
+ */
+static int get_subaction(struct ima_rule_entry *rule, enum ima_hooks func)
+{
+ if (!(rule->flags & IMA_FUNC))
+ return IMA_FILE_APPRAISE;
+
+ switch (func) {
+ case MMAP_CHECK:
+ return IMA_MMAP_APPRAISE;
+ case BPRM_CHECK:
+ return IMA_BPRM_APPRAISE;
+ case CREDS_CHECK:
+ return IMA_CREDS_APPRAISE;
+ case FILE_CHECK:
+ case POST_SETATTR:
+ return IMA_FILE_APPRAISE;
+ case MODULE_CHECK ... MAX_CHECK - 1:
+ default:
+ return IMA_READ_APPRAISE;
+ }
+}
+
+/**
+ * ima_match_policy - decision based on LSM and other conditions
+ * @inode: pointer to an inode for which the policy decision is being made
+ * @cred: pointer to a credentials structure for which the policy decision is
+ * being made
+ * @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.
+ *
+ * Since the IMA policy may be updated multiple times we need to lock the
+ * list when walking it. Reads are many orders of magnitude more numerous
+ * 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,
+ 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) {
+
+ if (!(entry->action & actmask))
+ continue;
+
+ if (!ima_match_rules(entry, inode, cred, secid, func, mask,
+ keyring))
+ continue;
+
+ action |= entry->flags & IMA_ACTION_FLAGS;
+
+ action |= entry->action & IMA_DO_MASK;
+ if (entry->action & IMA_APPRAISE) {
+ action |= get_subaction(entry, func);
+ action &= ~IMA_HASH;
+ if (ima_fail_unverifiable_sigs)
+ action |= IMA_FAIL_UNVERIFIABLE_SIGS;
+ }
+
+
+ if (entry->action & IMA_DO_MASK)
+ actmask &= ~(entry->action | entry->action << 1);
+ else
+ actmask &= ~(entry->action | entry->action >> 1);
+
+ if ((pcr) && (entry->flags & IMA_PCR))
+ *pcr = entry->pcr;
+
+ if (template_desc && entry->template)
+ *template_desc = entry->template;
+
+ if (!actmask)
+ break;
+ }
+ rcu_read_unlock();
+
+ return action;
+}
+
+/*
+ * Initialize the ima_policy_flag variable based on the currently
+ * loaded policy. Based on this flag, the decision to short circuit
+ * out of a function or not call the function in the first place
+ * can be made earlier.
+ */
+void ima_update_policy_flag(void)
+{
+ struct ima_rule_entry *entry;
+
+ list_for_each_entry(entry, ima_rules, list) {
+ if (entry->action & IMA_DO_MASK)
+ ima_policy_flag |= entry->action;
+ }
+
+ ima_appraise |= (build_ima_appraise | temp_ima_appraise);
+ if (!ima_appraise)
+ ima_policy_flag &= ~IMA_APPRAISE;
+}
+
+static int ima_appraise_flag(enum ima_hooks func)
+{
+ if (func == MODULE_CHECK)
+ return IMA_APPRAISE_MODULES;
+ else if (func == FIRMWARE_CHECK)
+ return IMA_APPRAISE_FIRMWARE;
+ else if (func == POLICY_CHECK)
+ return IMA_APPRAISE_POLICY;
+ else if (func == KEXEC_KERNEL_CHECK)
+ return IMA_APPRAISE_KEXEC;
+ 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.
+ *
+ * ima_rules points to either the ima_default_rules or the
+ * the new ima_policy_rules.
+ */
+void __init ima_init_policy(void)
+{
+ int build_appraise_entries, arch_entries;
+
+ /* 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:
+ add_rules(original_measurement_rules,
+ ARRAY_SIZE(original_measurement_rules),
+ IMA_DEFAULT_POLICY);
+ break;
+ case DEFAULT_TCB:
+ add_rules(default_measurement_rules,
+ ARRAY_SIZE(default_measurement_rules),
+ IMA_DEFAULT_POLICY);
+ break;
+ default:
+ break;
+ }
+
+ /*
+ * 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)
+ */
+ 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. As the secure boot rules includes all of the build time
+ * rules, include either one or the other set of rules, but not both.
+ */
+ 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);
+ }
+
+ if (ima_use_appraise_tcb)
+ add_rules(default_appraise_rules,
+ ARRAY_SIZE(default_appraise_rules),
+ IMA_DEFAULT_POLICY);
+
+ ima_update_policy_flag();
+}
+
+/* Make sure we have a valid policy, at least containing some rules. */
+int ima_check_policy(void)
+{
+ if (list_empty(&ima_temp_rules))
+ return -EINVAL;
+ return 0;
+}
+
+/**
+ * ima_update_policy - update default_rules with new measure rules
+ *
+ * Called on file .release to update the default rules with a complete new
+ * policy. What we do here is to splice ima_policy_rules and ima_temp_rules so
+ * they make a queue. The policy may be updated multiple times and this is the
+ * RCU updater.
+ *
+ * Policy rules are never deleted so ima_policy_flag gets zeroed only once when
+ * we switch from the default policy to user defined.
+ */
+void ima_update_policy(void)
+{
+ struct list_head *policy = &ima_policy_rules;
+
+ list_splice_tail_init_rcu(&ima_temp_rules, policy, synchronize_rcu);
+
+ 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_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,
+ Opt_subj_user, Opt_subj_role, Opt_subj_type,
+ Opt_func, Opt_mask, Opt_fsmagic, Opt_fsname,
+ 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_appraise_flag,
+ Opt_permit_directio, Opt_pcr, Opt_template, Opt_keyrings,
+ Opt_err
+};
+
+static const match_table_t policy_tokens = {
+ {Opt_measure, "measure"},
+ {Opt_dont_measure, "dont_measure"},
+ {Opt_appraise, "appraise"},
+ {Opt_dont_appraise, "dont_appraise"},
+ {Opt_audit, "audit"},
+ {Opt_hash, "hash"},
+ {Opt_dont_hash, "dont_hash"},
+ {Opt_obj_user, "obj_user=%s"},
+ {Opt_obj_role, "obj_role=%s"},
+ {Opt_obj_type, "obj_type=%s"},
+ {Opt_subj_user, "subj_user=%s"},
+ {Opt_subj_role, "subj_role=%s"},
+ {Opt_subj_type, "subj_type=%s"},
+ {Opt_func, "func=%s"},
+ {Opt_mask, "mask=%s"},
+ {Opt_fsmagic, "fsmagic=%s"},
+ {Opt_fsname, "fsname=%s"},
+ {Opt_fsuuid, "fsuuid=%s"},
+ {Opt_uid_eq, "uid=%s"},
+ {Opt_euid_eq, "euid=%s"},
+ {Opt_fowner_eq, "fowner=%s"},
+ {Opt_uid_gt, "uid>%s"},
+ {Opt_euid_gt, "euid>%s"},
+ {Opt_fowner_gt, "fowner>%s"},
+ {Opt_uid_lt, "uid<%s"},
+ {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}
+};
+
+static int ima_lsm_rule_init(struct ima_rule_entry *entry,
+ substring_t *args, int lsm_rule, int audit_type)
+{
+ int result;
+
+ if (entry->lsm[lsm_rule].rule)
+ return -EINVAL;
+
+ entry->lsm[lsm_rule].args_p = match_strdup(args);
+ if (!entry->lsm[lsm_rule].args_p)
+ return -ENOMEM;
+
+ entry->lsm[lsm_rule].type = audit_type;
+ 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) {
+ 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;
+}
+
+static void ima_log_string_op(struct audit_buffer *ab, char *key, char *value,
+ bool (*rule_operator)(kuid_t, kuid_t))
+{
+ if (!ab)
+ return;
+
+ if (rule_operator == &uid_gt)
+ audit_log_format(ab, "%s>", key);
+ else if (rule_operator == &uid_lt)
+ audit_log_format(ab, "%s<", key);
+ else
+ audit_log_format(ab, "%s=", key);
+ audit_log_format(ab, "%s ", value);
+}
+static void ima_log_string(struct audit_buffer *ab, char *key, char *value)
+{
+ 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,
+ AUDIT_INTEGRITY_POLICY_RULE);
+
+ entry->uid = INVALID_UID;
+ entry->fowner = INVALID_UID;
+ entry->uid_op = &uid_eq;
+ entry->fowner_op = &uid_eq;
+ entry->action = UNKNOWN;
+ while ((p = strsep(&rule, " \t")) != NULL) {
+ substring_t args[MAX_OPT_ARGS];
+ int token;
+ unsigned long lnum;
+
+ if (result < 0)
+ break;
+ if ((*p == '\0') || (*p == ' ') || (*p == '\t'))
+ continue;
+ token = match_token(p, policy_tokens, args);
+ switch (token) {
+ case Opt_measure:
+ ima_log_string(ab, "action", "measure");
+
+ if (entry->action != UNKNOWN)
+ result = -EINVAL;
+
+ entry->action = MEASURE;
+ break;
+ case Opt_dont_measure:
+ ima_log_string(ab, "action", "dont_measure");
+
+ if (entry->action != UNKNOWN)
+ result = -EINVAL;
+
+ entry->action = DONT_MEASURE;
+ break;
+ case Opt_appraise:
+ ima_log_string(ab, "action", "appraise");
+
+ if (entry->action != UNKNOWN)
+ result = -EINVAL;
+
+ entry->action = APPRAISE;
+ break;
+ case Opt_dont_appraise:
+ ima_log_string(ab, "action", "dont_appraise");
+
+ if (entry->action != UNKNOWN)
+ result = -EINVAL;
+
+ entry->action = DONT_APPRAISE;
+ break;
+ case Opt_audit:
+ ima_log_string(ab, "action", "audit");
+
+ if (entry->action != UNKNOWN)
+ result = -EINVAL;
+
+ entry->action = AUDIT;
+ break;
+ case Opt_hash:
+ ima_log_string(ab, "action", "hash");
+
+ if (entry->action != UNKNOWN)
+ result = -EINVAL;
+
+ entry->action = HASH;
+ break;
+ case Opt_dont_hash:
+ ima_log_string(ab, "action", "dont_hash");
+
+ if (entry->action != UNKNOWN)
+ result = -EINVAL;
+
+ entry->action = DONT_HASH;
+ break;
+ case Opt_func:
+ ima_log_string(ab, "func", args[0].from);
+
+ if (entry->func)
+ result = -EINVAL;
+
+ if (strcmp(args[0].from, "FILE_CHECK") == 0)
+ entry->func = FILE_CHECK;
+ /* PATH_CHECK is for backwards compat */
+ else if (strcmp(args[0].from, "PATH_CHECK") == 0)
+ entry->func = FILE_CHECK;
+ else if (strcmp(args[0].from, "MODULE_CHECK") == 0)
+ entry->func = MODULE_CHECK;
+ else if (strcmp(args[0].from, "FIRMWARE_CHECK") == 0)
+ entry->func = FIRMWARE_CHECK;
+ else if ((strcmp(args[0].from, "FILE_MMAP") == 0)
+ || (strcmp(args[0].from, "MMAP_CHECK") == 0))
+ entry->func = MMAP_CHECK;
+ else if (strcmp(args[0].from, "BPRM_CHECK") == 0)
+ entry->func = BPRM_CHECK;
+ else if (strcmp(args[0].from, "CREDS_CHECK") == 0)
+ entry->func = CREDS_CHECK;
+ else if (strcmp(args[0].from, "KEXEC_KERNEL_CHECK") ==
+ 0)
+ entry->func = KEXEC_KERNEL_CHECK;
+ else if (strcmp(args[0].from, "KEXEC_INITRAMFS_CHECK")
+ == 0)
+ 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)
+ entry->flags |= IMA_FUNC;
+ break;
+ case Opt_mask:
+ ima_log_string(ab, "mask", args[0].from);
+
+ if (entry->mask)
+ result = -EINVAL;
+
+ from = args[0].from;
+ if (*from == '^')
+ from++;
+
+ if ((strcmp(from, "MAY_EXEC")) == 0)
+ entry->mask = MAY_EXEC;
+ else if (strcmp(from, "MAY_WRITE") == 0)
+ entry->mask = MAY_WRITE;
+ else if (strcmp(from, "MAY_READ") == 0)
+ entry->mask = MAY_READ;
+ else if (strcmp(from, "MAY_APPEND") == 0)
+ entry->mask = MAY_APPEND;
+ else
+ result = -EINVAL;
+ if (!result)
+ entry->flags |= (*args[0].from == '^')
+ ? IMA_INMASK : IMA_MASK;
+ break;
+ case Opt_fsmagic:
+ ima_log_string(ab, "fsmagic", args[0].from);
+
+ if (entry->fsmagic) {
+ result = -EINVAL;
+ break;
+ }
+
+ result = kstrtoul(args[0].from, 16, &entry->fsmagic);
+ if (!result)
+ entry->flags |= IMA_FSMAGIC;
+ break;
+ case Opt_fsname:
+ ima_log_string(ab, "fsname", args[0].from);
+
+ entry->fsname = kstrdup(args[0].from, GFP_KERNEL);
+ if (!entry->fsname) {
+ result = -ENOMEM;
+ break;
+ }
+ 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);
+
+ if (!uuid_is_null(&entry->fsuuid)) {
+ result = -EINVAL;
+ break;
+ }
+
+ result = uuid_parse(args[0].from, &entry->fsuuid);
+ if (!result)
+ entry->flags |= IMA_FSUUID;
+ break;
+ 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) ||
+ (token == Opt_uid_gt) ||
+ (token == Opt_uid_lt);
+
+ ima_log_string_op(ab, uid_token ? "uid" : "euid",
+ args[0].from, entry->uid_op);
+
+ if (uid_valid(entry->uid)) {
+ result = -EINVAL;
+ break;
+ }
+
+ result = kstrtoul(args[0].from, 10, &lnum);
+ if (!result) {
+ entry->uid = make_kuid(current_user_ns(),
+ (uid_t) lnum);
+ if (!uid_valid(entry->uid) ||
+ (uid_t)lnum != lnum)
+ result = -EINVAL;
+ else
+ entry->flags |= uid_token
+ ? IMA_UID : IMA_EUID;
+ }
+ 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);
+
+ if (uid_valid(entry->fowner)) {
+ result = -EINVAL;
+ break;
+ }
+
+ result = kstrtoul(args[0].from, 10, &lnum);
+ if (!result) {
+ entry->fowner = make_kuid(current_user_ns(), (uid_t)lnum);
+ if (!uid_valid(entry->fowner) || (((uid_t)lnum) != lnum))
+ result = -EINVAL;
+ else
+ entry->flags |= IMA_FOWNER;
+ }
+ break;
+ case Opt_obj_user:
+ ima_log_string(ab, "obj_user", args[0].from);
+ result = ima_lsm_rule_init(entry, args,
+ LSM_OBJ_USER,
+ AUDIT_OBJ_USER);
+ break;
+ case Opt_obj_role:
+ ima_log_string(ab, "obj_role", args[0].from);
+ result = ima_lsm_rule_init(entry, args,
+ LSM_OBJ_ROLE,
+ AUDIT_OBJ_ROLE);
+ break;
+ case Opt_obj_type:
+ ima_log_string(ab, "obj_type", args[0].from);
+ result = ima_lsm_rule_init(entry, args,
+ LSM_OBJ_TYPE,
+ AUDIT_OBJ_TYPE);
+ break;
+ case Opt_subj_user:
+ ima_log_string(ab, "subj_user", args[0].from);
+ result = ima_lsm_rule_init(entry, args,
+ LSM_SUBJ_USER,
+ AUDIT_SUBJ_USER);
+ break;
+ case Opt_subj_role:
+ ima_log_string(ab, "subj_role", args[0].from);
+ result = ima_lsm_rule_init(entry, args,
+ LSM_SUBJ_ROLE,
+ AUDIT_SUBJ_ROLE);
+ break;
+ case Opt_subj_type:
+ ima_log_string(ab, "subj_type", args[0].from);
+ result = ima_lsm_rule_init(entry, args,
+ LSM_SUBJ_TYPE,
+ AUDIT_SUBJ_TYPE);
+ break;
+ case Opt_appraise_type:
+ 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;
+ case Opt_permit_directio:
+ entry->flags |= IMA_PERMIT_DIRECTIO;
+ break;
+ case Opt_pcr:
+ ima_log_string(ab, "pcr", args[0].from);
+
+ result = kstrtoint(args[0].from, 10, &entry->pcr);
+ if (result || INVALID_PCR(entry->pcr))
+ result = -EINVAL;
+ else
+ 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 && !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);
+ return result;
+}
+
+/**
+ * ima_parse_add_rule - add a rule to ima_policy_rules
+ * @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
+ */
+ssize_t ima_parse_add_rule(char *rule)
+{
+ static const char op[] = "update_policy";
+ char *p;
+ struct ima_rule_entry *entry;
+ ssize_t result, len;
+ int audit_info = 0;
+
+ p = strsep(&rule, "\n");
+ len = strlen(p) + 1;
+ p += strspn(p, " \t");
+
+ if (*p == '#' || *p == '\0')
+ return len;
+
+ entry = kzalloc(sizeof(*entry), GFP_KERNEL);
+ if (!entry) {
+ integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL,
+ NULL, op, "-ENOMEM", -ENOMEM, audit_info);
+ return -ENOMEM;
+ }
+
+ INIT_LIST_HEAD(&entry->list);
+
+ result = ima_parse_rule(p, entry);
+ if (result) {
+ ima_free_rule(entry);
+ integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL,
+ NULL, op, "invalid-policy", result,
+ audit_info);
+ return result;
+ }
+
+ list_add_tail(&entry->list, &ima_temp_rules);
+
+ return len;
+}
+
+/**
+ * ima_delete_rules() called to cleanup invalid in-flight policy.
+ * We don't need locking as we operate on the temp list, which is
+ * different from the active one. There is also only one user of
+ * ima_delete_rules() at a time.
+ */
+void ima_delete_rules(void)
+{
+ struct ima_rule_entry *entry, *tmp;
+
+ temp_ima_appraise = 0;
+ list_for_each_entry_safe(entry, tmp, &ima_temp_rules, list) {
+ list_del(&entry->list);
+ 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 {
+ mask_exec = 0, mask_write, mask_read, mask_append
+};
+
+static const char *const mask_tokens[] = {
+ "^MAY_EXEC",
+ "^MAY_WRITE",
+ "^MAY_READ",
+ "^MAY_APPEND"
+};
+
+void *ima_policy_start(struct seq_file *m, loff_t *pos)
+{
+ loff_t l = *pos;
+ struct ima_rule_entry *entry;
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(entry, ima_rules, list) {
+ if (!l--) {
+ rcu_read_unlock();
+ return entry;
+ }
+ }
+ rcu_read_unlock();
+ return NULL;
+}
+
+void *ima_policy_next(struct seq_file *m, void *v, loff_t *pos)
+{
+ struct ima_rule_entry *entry = v;
+
+ rcu_read_lock();
+ entry = list_entry_rcu(entry->list.next, struct ima_rule_entry, list);
+ rcu_read_unlock();
+ (*pos)++;
+
+ return (&entry->list == ima_rules) ? NULL : entry;
+}
+
+void ima_policy_stop(struct seq_file *m, void *v)
+{
+}
+
+#define pt(token) policy_tokens[token].pattern
+#define mt(token) mask_tokens[token]
+
+/*
+ * policy_func_show - display the ima_hooks policy rule
+ */
+static void policy_func_show(struct seq_file *m, enum ima_hooks func)
+{
+ if (func > 0 && func < MAX_CHECK)
+ seq_printf(m, "func=%s ", func_tokens[func]);
+ else
+ 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;
+ int i;
+ char tbuf[64] = {0,};
+ 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));
+ if (entry->action & DONT_MEASURE)
+ seq_puts(m, pt(Opt_dont_measure));
+ if (entry->action & APPRAISE)
+ seq_puts(m, pt(Opt_appraise));
+ if (entry->action & DONT_APPRAISE)
+ seq_puts(m, pt(Opt_dont_appraise));
+ if (entry->action & AUDIT)
+ seq_puts(m, pt(Opt_audit));
+ if (entry->action & HASH)
+ seq_puts(m, pt(Opt_hash));
+ if (entry->action & DONT_HASH)
+ seq_puts(m, pt(Opt_dont_hash));
+
+ seq_puts(m, " ");
+
+ if (entry->flags & IMA_FUNC)
+ policy_func_show(m, entry->func);
+
+ if ((entry->flags & IMA_MASK) || (entry->flags & IMA_INMASK)) {
+ if (entry->flags & IMA_MASK)
+ offset = 1;
+ if (entry->mask & MAY_EXEC)
+ seq_printf(m, pt(Opt_mask), mt(mask_exec) + offset);
+ if (entry->mask & MAY_WRITE)
+ seq_printf(m, pt(Opt_mask), mt(mask_write) + offset);
+ if (entry->mask & MAY_READ)
+ seq_printf(m, pt(Opt_mask), mt(mask_read) + offset);
+ if (entry->mask & MAY_APPEND)
+ seq_printf(m, pt(Opt_mask), mt(mask_append) + offset);
+ seq_puts(m, " ");
+ }
+
+ if (entry->flags & IMA_FSMAGIC) {
+ snprintf(tbuf, sizeof(tbuf), "0x%lx", entry->fsmagic);
+ seq_printf(m, pt(Opt_fsmagic), tbuf);
+ seq_puts(m, " ");
+ }
+
+ 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, " ");
+ }
+
+ if (entry->flags & IMA_PCR) {
+ snprintf(tbuf, sizeof(tbuf), "%d", entry->pcr);
+ seq_printf(m, pt(Opt_pcr), tbuf);
+ seq_puts(m, " ");
+ }
+
+ if (entry->flags & IMA_FSUUID) {
+ seq_printf(m, "fsuuid=%pU", &entry->fsuuid);
+ seq_puts(m, " ");
+ }
+
+ if (entry->flags & IMA_UID) {
+ snprintf(tbuf, sizeof(tbuf), "%d", __kuid_val(entry->uid));
+ if (entry->uid_op == &uid_gt)
+ seq_printf(m, pt(Opt_uid_gt), tbuf);
+ else if (entry->uid_op == &uid_lt)
+ seq_printf(m, pt(Opt_uid_lt), tbuf);
+ else
+ seq_printf(m, pt(Opt_uid_eq), tbuf);
+ seq_puts(m, " ");
+ }
+
+ if (entry->flags & IMA_EUID) {
+ snprintf(tbuf, sizeof(tbuf), "%d", __kuid_val(entry->uid));
+ if (entry->uid_op == &uid_gt)
+ seq_printf(m, pt(Opt_euid_gt), tbuf);
+ else if (entry->uid_op == &uid_lt)
+ seq_printf(m, pt(Opt_euid_lt), tbuf);
+ else
+ seq_printf(m, pt(Opt_euid_eq), tbuf);
+ seq_puts(m, " ");
+ }
+
+ if (entry->flags & IMA_FOWNER) {
+ snprintf(tbuf, sizeof(tbuf), "%d", __kuid_val(entry->fowner));
+ if (entry->fowner_op == &uid_gt)
+ seq_printf(m, pt(Opt_fowner_gt), tbuf);
+ else if (entry->fowner_op == &uid_lt)
+ seq_printf(m, pt(Opt_fowner_lt), tbuf);
+ else
+ seq_printf(m, pt(Opt_fowner_eq), tbuf);
+ seq_puts(m, " ");
+ }
+
+ for (i = 0; i < MAX_LSM_RULES; i++) {
+ if (entry->lsm[i].rule) {
+ switch (i) {
+ case LSM_OBJ_USER:
+ seq_printf(m, pt(Opt_obj_user),
+ entry->lsm[i].args_p);
+ break;
+ case LSM_OBJ_ROLE:
+ seq_printf(m, pt(Opt_obj_role),
+ entry->lsm[i].args_p);
+ break;
+ case LSM_OBJ_TYPE:
+ seq_printf(m, pt(Opt_obj_type),
+ entry->lsm[i].args_p);
+ break;
+ case LSM_SUBJ_USER:
+ seq_printf(m, pt(Opt_subj_user),
+ entry->lsm[i].args_p);
+ break;
+ case LSM_SUBJ_ROLE:
+ seq_printf(m, pt(Opt_subj_role),
+ entry->lsm[i].args_p);
+ break;
+ case LSM_SUBJ_TYPE:
+ seq_printf(m, pt(Opt_subj_type),
+ entry->lsm[i].args_p);
+ break;
+ }
+ seq_puts(m, " ");
+ }
+ }
+ 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();
+ seq_puts(m, "\n");
+ 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 */