summaryrefslogtreecommitdiff
path: root/security/integrity/ima/ima_policy.c
diff options
context:
space:
mode:
Diffstat (limited to 'security/integrity/ima/ima_policy.c')
-rw-r--r--security/integrity/ima/ima_policy.c2119
1 files changed, 1896 insertions, 223 deletions
diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
index 399433ad614e..8fbd8755f5bc 100644
--- a/security/integrity/ima/ima_policy.c
+++ b/security/integrity/ima/ima_policy.c
@@ -1,32 +1,44 @@
+// 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
- *
+ * - 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>
#include <linux/parser.h>
#include <linux/slab.h>
-#include <linux/genhd.h>
+#include <linux/rculist.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_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 IMA_LABEL 0x0800
+#define IMA_VALIDATE_ALGOS 0x1000
+#define IMA_GID 0x2000
+#define IMA_EGID 0x4000
+#define IMA_FGROUP 0x8000
+#define IMA_FS_SUBTYPE 0x10000
#define UNKNOWN 0
#define MEASURE 0x0001 /* same as IMA_MEASURE */
@@ -34,12 +46,57 @@
#define APPRAISE 0x0004 /* same as IMA_APPRAISE */
#define DONT_APPRAISE 0x0008
#define AUDIT 0x0040
+#define DONT_AUDIT 0x0080
+#define HASH 0x0100
+#define DONT_HASH 0x0200
+
+#define INVALID_PCR(a) (((a) < 0) || \
+ (a) >= (sizeof_field(struct ima_iint_cache, measured_pcrs) * 8))
+
+int ima_policy_flag;
+static int temp_ima_appraise;
+static int build_ima_appraise __ro_after_init;
+
+atomic_t ima_setxattr_allowed_hash_algorithms;
#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[] __counted_by(count);
+};
+
+/*
+ * These comparators are needed nowhere outside of ima so just define them here.
+ * This pattern should hopefully never be needed outside of ima.
+ */
+static inline bool vfsuid_gt_kuid(vfsuid_t vfsuid, kuid_t kuid)
+{
+ return __vfsuid_val(vfsuid) > __kuid_val(kuid);
+}
+
+static inline bool vfsgid_gt_kgid(vfsgid_t vfsgid, kgid_t kgid)
+{
+ return __vfsgid_val(vfsgid) > __kgid_val(kgid);
+}
+
+static inline bool vfsuid_lt_kuid(vfsuid_t vfsuid, kuid_t kuid)
+{
+ return __vfsuid_val(vfsuid) < __kuid_val(kuid);
+}
+
+static inline bool vfsgid_lt_kgid(vfsgid_t vfsgid, kgid_t kgid)
+{
+ return __vfsgid_val(vfsgid) < __kgid_val(kgid);
+}
+
struct ima_rule_entry {
struct list_head list;
int action;
@@ -47,19 +104,41 @@ struct ima_rule_entry {
enum ima_hooks func;
int mask;
unsigned long fsmagic;
- u8 fsuuid[16];
+ uuid_t fsuuid;
kuid_t uid;
+ kgid_t gid;
kuid_t fowner;
+ kgid_t fgroup;
+ bool (*uid_op)(kuid_t cred_uid, kuid_t rule_uid); /* Handlers for operators */
+ bool (*gid_op)(kgid_t cred_gid, kgid_t rule_gid);
+ bool (*fowner_op)(vfsuid_t vfsuid, kuid_t rule_uid); /* vfsuid_eq_kuid(), vfsuid_gt_kuid(), vfsuid_lt_kuid() */
+ bool (*fgroup_op)(vfsgid_t vfsgid, kgid_t rule_gid); /* vfsgid_eq_kgid(), vfsgid_gt_kgid(), vfsgid_lt_kgid() */
+ int pcr;
+ unsigned int allowed_algos; /* bitfield of allowed hash algorithms */
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;
+ char *fs_subtype;
+ struct ima_rule_opt_list *keyrings; /* Measure keys added to these keyrings */
+ struct ima_rule_opt_list *label; /* Measure data grouped under this label */
+ struct ima_template_desc *template;
};
/*
+ * sanity check in case the kernels gains more hash algorithms that can
+ * fit in an unsigned int
+ */
+static_assert(
+ 8 * sizeof(unsigned int) >= HASH_ALGO__LAST,
+ "The bitfield allowed_algos in ima_rule_entry is too small to contain all the supported hash algorithms, consider using a bigger type");
+
+/*
* Without LSM specific knowledge, the default policy can only be
- * written in terms of .action, .func, .mask, .fsmagic, .uid, and .fowner
+ * written in terms of .action, .func, .mask, .fsmagic, .uid, .gid,
+ * .fowner, and .fgroup
*/
/*
@@ -68,299 +147,959 @@ struct ima_rule_entry {
* normal users can easily run the machine out of memory simply building
* and running executables.
*/
-static struct ima_rule_entry default_rules[] = {
- {.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 = RAMFS_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 = MEASURE,.func = MMAP_CHECK,.mask = MAY_EXEC,
+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, .func = FILE_CHECK,
+ .flags = IMA_FSMAGIC | IMA_FUNC},
+ {.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,
+ {.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,
+ {.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 = 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 = &vfsuid_eq_kuid,
+ .flags = IMA_FOWNER},
+#else
+ /* force signature */
+ {.action = APPRAISE, .fowner = GLOBAL_ROOT_UID, .fowner_op = &vfsuid_eq_kuid,
+ .flags = IMA_FOWNER | IMA_DIGSIG_REQUIRED},
+#endif
};
-static struct ima_rule_entry default_appraise_rules[] = {
- {.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 = CGROUP_SUPER_MAGIC,.flags = IMA_FSMAGIC},
- {.action = APPRAISE,.fowner = GLOBAL_ROOT_UID,.flags = IMA_FOWNER},
+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 | IMA_MODSIG_ALLOWED |
+ IMA_CHECK_BLACKLIST},
+ {.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},
+};
+
+static struct ima_rule_entry critical_data_rules[] __ro_after_init = {
+ {.action = MEASURE, .func = CRITICAL_DATA, .flags = IMA_FUNC},
+};
+
+/* 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 struct list_head *ima_rules;
+static LIST_HEAD(ima_temp_rules);
+static struct list_head __rcu *ima_rules = (struct list_head __rcu *)(&ima_default_rules);
-static DEFINE_MUTEX(ima_rules_mutex);
+static int ima_policy __initdata;
-static bool ima_use_tcb __initdata;
static int __init default_measure_policy_setup(char *str)
{
- ima_use_tcb = 1;
+ 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_use_critical_data __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, "critical_data") == 0)
+ ima_use_critical_data = 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 = 1;
+ ima_use_appraise_tcb = true;
return 1;
}
__setup("ima_appraise_tcb", default_appraise_policy_setup);
-/*
- * Although the IMA policy does not change, 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.
+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);
+ }
+ opt_list->count = count;
+
+ /*
+ * 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;
+ }
+
+ 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);
+ kfree(entry->fs_subtype);
+ 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,
+ gfp_t gfp)
+{
+ 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);
+ 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,
+ gfp);
+ 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, GFP_KERNEL);
+ 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 references 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, *tmp;
+ struct ima_rule_entry *entry, *e;
int result;
- int i;
- mutex_lock(&ima_rules_mutex);
- list_for_each_entry_safe(entry, tmp, &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_rule_data - determine whether func_data matches the policy rule
+ * @rule: a pointer to a rule
+ * @func_data: data to match against the measure rule data
+ * @cred: a pointer to a credentials structure for user validation
+ *
+ * Returns true if func_data matches one in the rule, false otherwise.
+ */
+static bool ima_match_rule_data(struct ima_rule_entry *rule,
+ const char *func_data,
+ const struct cred *cred)
+{
+ const struct ima_rule_opt_list *opt_list = NULL;
+ bool matched = false;
+ size_t i;
+
+ if ((rule->flags & IMA_UID) && !rule->uid_op(cred->uid, rule->uid))
+ return false;
+
+ switch (rule->func) {
+ case KEY_CHECK:
+ if (!rule->keyrings)
+ return true;
+
+ opt_list = rule->keyrings;
+ break;
+ case CRITICAL_DATA:
+ if (!rule->label)
+ return true;
+
+ opt_list = rule->label;
+ break;
+ default:
+ return false;
+ }
+
+ if (!func_data)
+ return false;
+
+ for (i = 0; i < opt_list->count; i++) {
+ if (!strcmp(opt_list->items[i], func_data)) {
+ matched = true;
+ break;
}
}
- mutex_unlock(&ima_rules_mutex);
+
+ return matched;
}
/**
- * ima_match_rules - determine whether an inode matches the measure rule.
+ * ima_match_rules - determine whether an inode matches the policy rule.
* @rule: a pointer to a rule
+ * @idmap: idmap of the mount the inode was found from
* @inode: a pointer to an inode
+ * @cred: a pointer to a credentials structure for user validation
+ * @prop: LSM properties of the task to be validated
* @func: LIM hook identifier
* @mask: requested action (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC)
+ * @func_data: func specific data, may be NULL
*
* Returns true on rule match, false on failure.
*/
static bool ima_match_rules(struct ima_rule_entry *rule,
- struct inode *inode, enum ima_hooks func, int mask)
+ struct mnt_idmap *idmap,
+ struct inode *inode, const struct cred *cred,
+ struct lsm_prop *prop, enum ima_hooks func, int mask,
+ const char *func_data)
{
- struct task_struct *tsk = current;
- const struct cred *cred = current_cred();
int i;
+ bool result = false;
+ struct ima_rule_entry *lsm_rule = rule;
+ bool rule_reinitialized = false;
+
+ if ((rule->flags & IMA_FUNC) &&
+ (rule->func != func && func != POST_SETATTR))
+ return false;
+
+ switch (func) {
+ case KEY_CHECK:
+ case CRITICAL_DATA:
+ return ((rule->func == func) &&
+ ima_match_rule_data(rule, func_data, cred));
+ default:
+ break;
+ }
- if ((rule->flags & IMA_FUNC) && rule->func != func)
+ if ((rule->flags & IMA_MASK) &&
+ (rule->mask != mask && func != POST_SETATTR))
return false;
- if ((rule->flags & IMA_MASK) && rule->mask != mask)
+ 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_FS_SUBTYPE) {
+ if (!inode->i_sb->s_subtype)
+ return false;
+ if (strcmp(rule->fs_subtype, inode->i_sb->s_subtype))
+ return false;
+ }
if ((rule->flags & IMA_FSUUID) &&
- memcmp(rule->fsuuid, inode->i_sb->s_uuid, sizeof(rule->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_GID) && !rule->gid_op(cred->gid, rule->gid))
return false;
- if ((rule->flags & IMA_UID) && !uid_eq(rule->uid, cred->uid))
+ if (rule->flags & IMA_EGID) {
+ if (has_capability_noaudit(current, CAP_SETGID)) {
+ if (!rule->gid_op(cred->egid, rule->gid)
+ && !rule->gid_op(cred->sgid, rule->gid)
+ && !rule->gid_op(cred->gid, rule->gid))
+ return false;
+ } else if (!rule->gid_op(cred->egid, rule->gid))
+ return false;
+ }
+ if ((rule->flags & IMA_FOWNER) &&
+ !rule->fowner_op(i_uid_into_vfsuid(idmap, inode),
+ rule->fowner))
return false;
- if ((rule->flags & IMA_FOWNER) && !uid_eq(rule->fowner, inode->i_uid))
+ if ((rule->flags & IMA_FGROUP) &&
+ !rule->fgroup_op(i_gid_into_vfsgid(idmap, inode),
+ rule->fgroup))
return false;
for (i = 0; i < MAX_LSM_RULES; i++) {
int rc = 0;
- u32 osid, sid;
- int retried = 0;
+ struct lsm_prop inode_prop = { };
+
+ if (!lsm_rule->lsm[i].rule) {
+ if (!lsm_rule->lsm[i].args_p)
+ continue;
+ else
+ return false;
+ }
- if (!rule->lsm[i].rule)
- continue;
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);
+ security_inode_getlsmprop(inode, &inode_prop);
+ rc = ima_filter_rule_match(&inode_prop,
+ 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:
- security_task_getsecid(tsk, &sid);
- rc = security_filter_rule_match(sid,
- rule->lsm[i].type,
- Audit_equal,
- rule->lsm[i].rule,
- NULL);
+ rc = ima_filter_rule_match(prop, 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)
- return false;
+
+ if (rc == -ESTALE && !rule_reinitialized) {
+ lsm_rule = ima_lsm_copy_rule(rule, GFP_ATOMIC);
+ if (lsm_rule) {
+ rule_reinitialized = true;
+ goto retry;
+ }
+ }
+ if (rc <= 0) {
+ 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;
}
/*
* 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, int func)
+static int get_subaction(struct ima_rule_entry *rule, enum ima_hooks func)
{
if (!(rule->flags & IMA_FUNC))
return IMA_FILE_APPRAISE;
- switch(func) {
+ switch (func) {
case MMAP_CHECK:
+ case MMAP_CHECK_REQPROT:
return IMA_MMAP_APPRAISE;
case BPRM_CHECK:
return IMA_BPRM_APPRAISE;
- case MODULE_CHECK:
- return IMA_MODULE_APPRAISE;
+ case CREDS_CHECK:
+ return IMA_CREDS_APPRAISE;
case FILE_CHECK:
- default:
+ 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
+ * @idmap: idmap of the mount the inode was found from
* @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
+ * @prop: LSM properties 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
+ * @func_data: func specific data, may be NULL
+ * @allowed_algos: allowlist of hash algorithms for the IMA xattr
*
* Measure decision based on func/mask/fsmagic and LSM(subj/obj/type)
* conditions.
*
- * (There is no need for locking when walking the policy list,
- * as elements in the list are never deleted, nor does the list
- * change.)
+ * 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, enum ima_hooks func, int mask,
- int flags)
+int ima_match_policy(struct mnt_idmap *idmap, struct inode *inode,
+ const struct cred *cred, struct lsm_prop *prop,
+ enum ima_hooks func, int mask, int flags, int *pcr,
+ struct ima_template_desc **template_desc,
+ const char *func_data, unsigned int *allowed_algos)
{
struct ima_rule_entry *entry;
int action = 0, actmask = flags | (flags << 1);
+ struct list_head *ima_rules_tmp;
- list_for_each_entry(entry, ima_rules, list) {
+ if (template_desc && !*template_desc)
+ *template_desc = ima_template_desc_current();
+
+ rcu_read_lock();
+ ima_rules_tmp = rcu_dereference(ima_rules);
+ list_for_each_entry_rcu(entry, ima_rules_tmp, list) {
if (!(entry->action & actmask))
continue;
- if (!ima_match_rules(entry, inode, func, mask))
+ if (!ima_match_rules(entry, idmap, inode, cred, prop,
+ func, mask, func_data))
continue;
- action |= entry->flags & IMA_ACTION_FLAGS;
+ action |= entry->flags & IMA_NONACTION_FLAGS;
action |= entry->action & IMA_DO_MASK;
- if (entry->action & IMA_APPRAISE)
+ if (entry->action & IMA_APPRAISE) {
action |= get_subaction(entry, func);
+ action &= ~IMA_HASH;
+ if (ima_fail_unverifiable_sigs)
+ action |= IMA_FAIL_UNVERIFIABLE_SIGS;
+
+ if (allowed_algos &&
+ entry->flags & IMA_VALIDATE_ALGOS)
+ *allowed_algos = entry->allowed_algos;
+ }
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;
}
/**
+ * ima_update_policy_flags() - Update global IMA variables
+ *
+ * Update ima_policy_flag and ima_setxattr_allowed_hash_algorithms
+ * based on the currently loaded policy.
+ *
+ * With ima_policy_flag, the decision to short circuit out of a function
+ * or not call the function in the first place can be made earlier.
+ *
+ * With ima_setxattr_allowed_hash_algorithms, the policy can restrict the
+ * set of hash algorithms accepted when updating the security.ima xattr of
+ * a file.
+ *
+ * Context: called after a policy update and at system initialization.
+ */
+void ima_update_policy_flags(void)
+{
+ struct ima_rule_entry *entry;
+ int new_policy_flag = 0;
+ struct list_head *ima_rules_tmp;
+
+ rcu_read_lock();
+ ima_rules_tmp = rcu_dereference(ima_rules);
+ list_for_each_entry_rcu(entry, ima_rules_tmp, list) {
+ /*
+ * SETXATTR_CHECK rules do not implement a full policy check
+ * because rule checking would probably have an important
+ * performance impact on setxattr(). As a consequence, only one
+ * SETXATTR_CHECK can be active at a given time.
+ * Because we want to preserve that property, we set out to use
+ * atomic_cmpxchg. Either:
+ * - the atomic was non-zero: a setxattr hash policy is
+ * already enforced, we do nothing
+ * - the atomic was zero: no setxattr policy was set, enable
+ * the setxattr hash policy
+ */
+ if (entry->func == SETXATTR_CHECK) {
+ atomic_cmpxchg(&ima_setxattr_allowed_hash_algorithms,
+ 0, entry->allowed_algos);
+ /* SETXATTR_CHECK doesn't impact ima_policy_flag */
+ continue;
+ }
+
+ if (entry->action & IMA_DO_MASK)
+ new_policy_flag |= entry->action;
+ }
+ rcu_read_unlock();
+
+ ima_appraise |= (build_ima_appraise | temp_ima_appraise);
+ if (!ima_appraise)
+ new_policy_flag &= ~IMA_APPRAISE;
+
+ ima_policy_flag = new_policy_flag;
+}
+
+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 = strscpy(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.
+ * ima_rules points to either the ima_default_rules or the new ima_policy_rules.
*/
void __init ima_init_policy(void)
{
- int i, measure_entries, appraise_entries;
-
- /* if !ima_use_tcb set entries = 0 so we load NO default rules */
- measure_entries = ima_use_tcb ? ARRAY_SIZE(default_rules) : 0;
- appraise_entries = ima_use_appraise_tcb ?
- ARRAY_SIZE(default_appraise_rules) : 0;
-
- for (i = 0; i < measure_entries + appraise_entries; i++) {
- if (i < measure_entries)
- list_add_tail(&default_rules[i].list,
- &ima_default_rules);
- else {
- int j = i - measure_entries;
-
- list_add_tail(&default_appraise_rules[j].list,
- &ima_default_rules);
- }
+ 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);
}
- ima_rules = &ima_default_rules;
+ if (ima_use_appraise_tcb)
+ add_rules(default_appraise_rules,
+ ARRAY_SIZE(default_appraise_rules),
+ IMA_DEFAULT_POLICY);
+
+ if (ima_use_critical_data)
+ add_rules(critical_data_rules,
+ ARRAY_SIZE(critical_data_rules),
+ IMA_DEFAULT_POLICY);
+
+ atomic_set(&ima_setxattr_allowed_hash_algorithms, 0);
+
+ ima_update_policy_flags();
+}
+
+/* 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. Once updated, the policy is locked, no additional rules can be
- * added to the policy.
+ * 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)
{
- const char *op = "policy_update";
- const char *cause = "already exists";
- int result = 1;
- int audit_info = 0;
+ struct list_head *policy = &ima_policy_rules;
+
+ list_splice_tail_init_rcu(&ima_temp_rules, policy, synchronize_rcu);
+
+ if (ima_rules != (struct list_head __rcu *)policy) {
+ ima_policy_flag = 0;
- if (ima_rules == &ima_default_rules) {
- ima_rules = &ima_policy_rules;
- cause = "complete";
- result = 0;
+ rcu_assign_pointer(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);
}
- integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL,
- NULL, op, cause, result, audit_info);
+ ima_update_policy_flags();
+
+ /* Custom IMA policy has been loaded */
+ ima_process_queued_keys();
}
-enum {
- Opt_err = -1,
- Opt_measure = 1, Opt_dont_measure,
+/* Keep the enumeration in sync with the policy_tokens! */
+enum policy_opt {
+ Opt_measure, Opt_dont_measure,
Opt_appraise, Opt_dont_appraise,
- Opt_audit,
+ Opt_audit, Opt_dont_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_uid, Opt_fowner,
- Opt_appraise_type, Opt_fsuuid
+ Opt_func, Opt_mask, Opt_fsmagic, Opt_fsname, Opt_fs_subtype, Opt_fsuuid,
+ Opt_uid_eq, Opt_euid_eq, Opt_gid_eq, Opt_egid_eq,
+ Opt_fowner_eq, Opt_fgroup_eq,
+ Opt_uid_gt, Opt_euid_gt, Opt_gid_gt, Opt_egid_gt,
+ Opt_fowner_gt, Opt_fgroup_gt,
+ Opt_uid_lt, Opt_euid_lt, Opt_gid_lt, Opt_egid_lt,
+ Opt_fowner_lt, Opt_fgroup_lt,
+ Opt_digest_type,
+ Opt_appraise_type, Opt_appraise_flag, Opt_appraise_algos,
+ Opt_permit_directio, Opt_pcr, Opt_template, Opt_keyrings,
+ Opt_label, 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"},
{Opt_dont_appraise, "dont_appraise"},
{Opt_audit, "audit"},
+ {Opt_dont_audit, "dont_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"},
@@ -370,10 +1109,36 @@ static match_table_t policy_tokens = {
{Opt_func, "func=%s"},
{Opt_mask, "mask=%s"},
{Opt_fsmagic, "fsmagic=%s"},
+ {Opt_fsname, "fsname=%s"},
+ {Opt_fs_subtype, "fs_subtype=%s"},
{Opt_fsuuid, "fsuuid=%s"},
- {Opt_uid, "uid=%s"},
- {Opt_fowner, "fowner=%s"},
+ {Opt_uid_eq, "uid=%s"},
+ {Opt_euid_eq, "euid=%s"},
+ {Opt_gid_eq, "gid=%s"},
+ {Opt_egid_eq, "egid=%s"},
+ {Opt_fowner_eq, "fowner=%s"},
+ {Opt_fgroup_eq, "fgroup=%s"},
+ {Opt_uid_gt, "uid>%s"},
+ {Opt_euid_gt, "euid>%s"},
+ {Opt_gid_gt, "gid>%s"},
+ {Opt_egid_gt, "egid>%s"},
+ {Opt_fowner_gt, "fowner>%s"},
+ {Opt_fgroup_gt, "fgroup>%s"},
+ {Opt_uid_lt, "uid<%s"},
+ {Opt_euid_lt, "euid<%s"},
+ {Opt_gid_lt, "gid<%s"},
+ {Opt_egid_lt, "egid<%s"},
+ {Opt_fowner_lt, "fowner<%s"},
+ {Opt_fgroup_lt, "fgroup<%s"},
+ {Opt_digest_type, "digest_type=%s"},
{Opt_appraise_type, "appraise_type=%s"},
+ {Opt_appraise_flag, "appraise_flag=%s"},
+ {Opt_appraise_algos, "appraise_algos=%s"},
+ {Opt_permit_directio, "permit_directio"},
+ {Opt_pcr, "pcr=%s"},
+ {Opt_template, "template=%s"},
+ {Opt_keyrings, "keyrings=%s"},
+ {Opt_label, "label=%s"},
{Opt_err, NULL}
};
@@ -390,42 +1155,300 @@ static int ima_lsm_rule_init(struct ima_rule_entry *entry,
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,
+ GFP_KERNEL);
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 == (struct list_head __rcu *)(&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,
+ enum policy_opt rule_operator)
+{
+ if (!ab)
+ return;
+
+ switch (rule_operator) {
+ case Opt_uid_gt:
+ case Opt_euid_gt:
+ case Opt_gid_gt:
+ case Opt_egid_gt:
+ case Opt_fowner_gt:
+ case Opt_fgroup_gt:
+ audit_log_format(ab, "%s>", key);
+ break;
+ case Opt_uid_lt:
+ case Opt_euid_lt:
+ case Opt_gid_lt:
+ case Opt_egid_lt:
+ case Opt_fowner_lt:
+ case Opt_fgroup_lt:
+ audit_log_format(ab, "%s<", key);
+ break;
+ default:
+ 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)
{
- audit_log_format(ab, "%s=", key);
- audit_log_untrustedstring(ab, value);
- audit_log_format(ab, " ");
+ ima_log_string_op(ab, key, value, Opt_err);
+}
+
+/*
+ * 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
+}
+
+/*
+ * Warn if the template does not contain the given field.
+ */
+static void check_template_field(const struct ima_template_desc *template,
+ const char *field, const char *msg)
+{
+ int i;
+
+ for (i = 0; i < template->num_fields; i++)
+ if (!strcmp(template->fields[i]->field_id, field))
+ return;
+
+ pr_notice_once("%s", 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 | IMA_VALIDATE_ALGOS))
+ 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 MMAP_CHECK_REQPROT:
+ 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_FS_SUBTYPE |
+ IMA_GID | IMA_EGID |
+ IMA_FGROUP | IMA_DIGSIG_REQUIRED |
+ IMA_PERMIT_DIRECTIO | IMA_VALIDATE_ALGOS |
+ IMA_CHECK_BLACKLIST | IMA_VERITY_REQUIRED))
+ 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_FS_SUBTYPE |
+ IMA_GID | IMA_EGID |
+ IMA_FGROUP | IMA_DIGSIG_REQUIRED |
+ IMA_PERMIT_DIRECTIO | IMA_MODSIG_ALLOWED |
+ IMA_CHECK_BLACKLIST | IMA_VALIDATE_ALGOS))
+ 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 | IMA_FS_SUBTYPE |
+ IMA_GID | IMA_EGID |
+ IMA_FGROUP))
+ return false;
+
+ break;
+ case KEY_CHECK:
+ if (entry->action & ~(MEASURE | DONT_MEASURE))
+ return false;
+
+ if (entry->flags & ~(IMA_FUNC | IMA_UID | IMA_GID | IMA_PCR |
+ IMA_KEYRINGS))
+ return false;
+
+ if (ima_rule_contains_lsm_cond(entry))
+ return false;
+
+ break;
+ case CRITICAL_DATA:
+ if (entry->action & ~(MEASURE | DONT_MEASURE))
+ return false;
+
+ if (entry->flags & ~(IMA_FUNC | IMA_UID | IMA_GID | IMA_PCR |
+ IMA_LABEL))
+ return false;
+
+ if (ima_rule_contains_lsm_cond(entry))
+ return false;
+
+ break;
+ case SETXATTR_CHECK:
+ /* any action other than APPRAISE is unsupported */
+ if (entry->action != APPRAISE)
+ return false;
+
+ /* SETXATTR_CHECK requires an appraise_algos parameter */
+ if (!(entry->flags & IMA_VALIDATE_ALGOS))
+ return false;
+
+ /*
+ * full policies are not supported, they would have too
+ * much of a performance impact
+ */
+ if (entry->flags & ~(IMA_FUNC | IMA_VALIDATE_ALGOS))
+ 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_DIGSIG_REQUIRED))
+ return false;
+
+ /*
+ * Unlike for regular IMA 'appraise' policy rules where security.ima
+ * xattr may contain either a file hash or signature, the security.ima
+ * xattr for fsverity must contain a file signature (sigv3). Ensure
+ * that 'appraise' rules for fsverity require file signatures by
+ * checking the IMA_DIGSIG_REQUIRED flag is set.
+ */
+ if (entry->action == APPRAISE &&
+ (entry->flags & IMA_VERITY_REQUIRED) &&
+ !(entry->flags & IMA_DIGSIG_REQUIRED))
+ return false;
+
+ return true;
+}
+
+static unsigned int ima_parse_appraise_algos(char *arg)
+{
+ unsigned int res = 0;
+ int idx;
+ char *token;
+
+ while ((token = strsep(&arg, ",")) != NULL) {
+ idx = match_string(hash_algo_name, HASH_ALGO__LAST, token);
+
+ if (idx < 0) {
+ pr_err("unknown hash algorithm \"%s\"",
+ token);
+ return 0;
+ }
+
+ if (!crypto_has_alg(hash_algo_name[idx], 0, 0)) {
+ pr_err("unavailable hash algorithm \"%s\", check your kernel configuration",
+ token);
+ return 0;
+ }
+
+ /* Add the hash algorithm to the 'allowed' bitfield */
+ res |= (1U << idx);
+ }
+
+ return res;
}
static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
{
struct audit_buffer *ab;
+ char *from;
char *p;
+ bool eid_token; /* either euid or egid */
+ struct ima_template_desc *template_desc;
int result = 0;
- ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_INTEGRITY_RULE);
+ ab = integrity_audit_log_start(audit_context(), GFP_KERNEL,
+ AUDIT_INTEGRITY_POLICY_RULE);
entry->uid = INVALID_UID;
+ entry->gid = INVALID_GID;
entry->fowner = INVALID_UID;
+ entry->fgroup = INVALID_GID;
+ entry->uid_op = &uid_eq;
+ entry->gid_op = &gid_eq;
+ entry->fowner_op = &vfsuid_eq_kuid;
+ entry->fgroup_op = &vfsgid_eq_kgid;
entry->action = UNKNOWN;
while ((p = strsep(&rule, " \t")) != NULL) {
substring_t args[MAX_OPT_ARGS];
int token;
unsigned long lnum;
- if (result < 0)
+ if (result < 0 || *p == '#') /* ignore suffixed comment */
break;
if ((*p == '\0') || (*p == ' ') || (*p == '\t'))
continue;
@@ -471,6 +1494,30 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
entry->action = AUDIT;
break;
+ case Opt_dont_audit:
+ ima_log_string(ab, "action", "dont_audit");
+
+ if (entry->action != UNKNOWN)
+ result = -EINVAL;
+
+ entry->action = DONT_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);
@@ -484,11 +1531,34 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
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, "MMAP_CHECK_REQPROT") == 0))
+ entry->func = MMAP_CHECK_REQPROT;
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 if (strcmp(args[0].from, "CRITICAL_DATA") == 0)
+ entry->func = CRITICAL_DATA;
+ else if (strcmp(args[0].from, "SETXATTR_CHECK") == 0)
+ entry->func = SETXATTR_CHECK;
else
result = -EINVAL;
if (!result)
@@ -500,18 +1570,23 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
if (entry->mask)
result = -EINVAL;
- if ((strcmp(args[0].from, "MAY_EXEC")) == 0)
+ from = args[0].from;
+ if (*from == '^')
+ from++;
+
+ if ((strcmp(from, "MAY_EXEC")) == 0)
entry->mask = MAY_EXEC;
- else if (strcmp(args[0].from, "MAY_WRITE") == 0)
+ else if (strcmp(from, "MAY_WRITE") == 0)
entry->mask = MAY_WRITE;
- else if (strcmp(args[0].from, "MAY_READ") == 0)
+ else if (strcmp(from, "MAY_READ") == 0)
entry->mask = MAY_READ;
- else if (strcmp(args[0].from, "MAY_APPEND") == 0)
+ else if (strcmp(from, "MAY_APPEND") == 0)
entry->mask = MAY_APPEND;
else
result = -EINVAL;
if (!result)
- entry->flags |= IMA_MASK;
+ entry->flags |= (*args[0].from == '^')
+ ? IMA_INMASK : IMA_MASK;
break;
case Opt_fsmagic:
ima_log_string(ab, "fsmagic", args[0].from);
@@ -521,59 +1596,206 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
break;
}
- result = strict_strtoul(args[0].from, 16,
- &entry->fsmagic);
+ 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_fs_subtype:
+ ima_log_string(ab, "fs_subtype", args[0].from);
+
+ if (entry->fs_subtype) {
+ result = -EINVAL;
+ break;
+ }
+
+ entry->fs_subtype = kstrdup(args[0].from, GFP_KERNEL);
+ if (!entry->fs_subtype) {
+ result = -ENOMEM;
+ break;
+ }
+ result = 0;
+ entry->flags |= IMA_FS_SUBTYPE;
+ 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_label:
+ ima_log_string(ab, "label", args[0].from);
+
+ if (entry->label) {
+ result = -EINVAL;
+ break;
+ }
+
+ entry->label = ima_alloc_rule_opt_list(args);
+ if (IS_ERR(entry->label)) {
+ result = PTR_ERR(entry->label);
+ entry->label = NULL;
+ break;
+ }
+
+ entry->flags |= IMA_LABEL;
+ break;
case Opt_fsuuid:
ima_log_string(ab, "fsuuid", args[0].from);
- if (memchr_inv(entry->fsuuid, 0x00,
- sizeof(entry->fsuuid))) {
+ if (!uuid_is_null(&entry->fsuuid)) {
result = -EINVAL;
break;
}
- result = blk_part_pack_uuid(args[0].from,
- entry->fsuuid);
+ result = uuid_parse(args[0].from, &entry->fsuuid);
if (!result)
entry->flags |= IMA_FSUUID;
break;
- case Opt_uid:
- ima_log_string(ab, "uid", args[0].from);
+ 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:
+ eid_token = (token == Opt_euid_eq) ||
+ (token == Opt_euid_gt) ||
+ (token == Opt_euid_lt);
+
+ ima_log_string_op(ab, eid_token ? "euid" : "uid",
+ args[0].from, token);
if (uid_valid(entry->uid)) {
result = -EINVAL;
break;
}
- result = strict_strtoul(args[0].from, 10, &lnum);
+ 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))
+ entry->uid = make_kuid(current_user_ns(),
+ (uid_t) lnum);
+ if (!uid_valid(entry->uid) ||
+ (uid_t)lnum != lnum)
result = -EINVAL;
else
- entry->flags |= IMA_UID;
+ entry->flags |= eid_token
+ ? IMA_EUID : IMA_UID;
}
break;
- case Opt_fowner:
- ima_log_string(ab, "fowner", args[0].from);
+ case Opt_gid_gt:
+ case Opt_egid_gt:
+ entry->gid_op = &gid_gt;
+ fallthrough;
+ case Opt_gid_lt:
+ case Opt_egid_lt:
+ if ((token == Opt_gid_lt) || (token == Opt_egid_lt))
+ entry->gid_op = &gid_lt;
+ fallthrough;
+ case Opt_gid_eq:
+ case Opt_egid_eq:
+ eid_token = (token == Opt_egid_eq) ||
+ (token == Opt_egid_gt) ||
+ (token == Opt_egid_lt);
+
+ ima_log_string_op(ab, eid_token ? "egid" : "gid",
+ args[0].from, token);
+
+ if (gid_valid(entry->gid)) {
+ result = -EINVAL;
+ break;
+ }
+
+ result = kstrtoul(args[0].from, 10, &lnum);
+ if (!result) {
+ entry->gid = make_kgid(current_user_ns(),
+ (gid_t)lnum);
+ if (!gid_valid(entry->gid) ||
+ (((gid_t)lnum) != lnum))
+ result = -EINVAL;
+ else
+ entry->flags |= eid_token
+ ? IMA_EGID : IMA_GID;
+ }
+ break;
+ case Opt_fowner_gt:
+ entry->fowner_op = &vfsuid_gt_kuid;
+ fallthrough;
+ case Opt_fowner_lt:
+ if (token == Opt_fowner_lt)
+ entry->fowner_op = &vfsuid_lt_kuid;
+ fallthrough;
+ case Opt_fowner_eq:
+ ima_log_string_op(ab, "fowner", args[0].from, token);
if (uid_valid(entry->fowner)) {
result = -EINVAL;
break;
}
- result = strict_strtoul(args[0].from, 10, &lnum);
+ 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))
+ 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_fgroup_gt:
+ entry->fgroup_op = &vfsgid_gt_kgid;
+ fallthrough;
+ case Opt_fgroup_lt:
+ if (token == Opt_fgroup_lt)
+ entry->fgroup_op = &vfsgid_lt_kgid;
+ fallthrough;
+ case Opt_fgroup_eq:
+ ima_log_string_op(ab, "fgroup", args[0].from, token);
+
+ if (gid_valid(entry->fgroup)) {
+ result = -EINVAL;
+ break;
+ }
+
+ result = kstrtoul(args[0].from, 10, &lnum);
+ if (!result) {
+ entry->fgroup = make_kgid(current_user_ns(),
+ (gid_t)lnum);
+ if (!gid_valid(entry->fgroup) ||
+ (((gid_t)lnum) != lnum))
+ result = -EINVAL;
+ else
+ entry->flags |= IMA_FGROUP;
+ }
+ break;
case Opt_obj_user:
ima_log_string(ab, "obj_user", args[0].from);
result = ima_lsm_rule_init(entry, args,
@@ -610,17 +1832,96 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
LSM_SUBJ_TYPE,
AUDIT_SUBJ_TYPE);
break;
+ case Opt_digest_type:
+ ima_log_string(ab, "digest_type", args[0].from);
+ if (entry->flags & IMA_DIGSIG_REQUIRED)
+ result = -EINVAL;
+ else if ((strcmp(args[0].from, "verity")) == 0)
+ entry->flags |= IMA_VERITY_REQUIRED;
+ else
+ result = -EINVAL;
+ break;
case Opt_appraise_type:
- if (entry->action != APPRAISE) {
+ ima_log_string(ab, "appraise_type", args[0].from);
+
+ if ((strcmp(args[0].from, "imasig")) == 0) {
+ if (entry->flags & IMA_VERITY_REQUIRED)
+ result = -EINVAL;
+ else
+ entry->flags |= IMA_DIGSIG_REQUIRED | IMA_CHECK_BLACKLIST;
+ } else if (strcmp(args[0].from, "sigv3") == 0) {
+ /* Only fsverity supports sigv3 for now */
+ if (entry->flags & IMA_VERITY_REQUIRED)
+ entry->flags |= IMA_DIGSIG_REQUIRED | IMA_CHECK_BLACKLIST;
+ else
+ result = -EINVAL;
+ } else if (IS_ENABLED(CONFIG_IMA_APPRAISE_MODSIG) &&
+ strcmp(args[0].from, "imasig|modsig") == 0) {
+ if (entry->flags & IMA_VERITY_REQUIRED)
+ result = -EINVAL;
+ else
+ entry->flags |= IMA_DIGSIG_REQUIRED |
+ IMA_MODSIG_ALLOWED | IMA_CHECK_BLACKLIST;
+ } else {
+ result = -EINVAL;
+ }
+ break;
+ case Opt_appraise_flag:
+ ima_log_string(ab, "appraise_flag", args[0].from);
+ break;
+ case Opt_appraise_algos:
+ ima_log_string(ab, "appraise_algos", args[0].from);
+
+ if (entry->allowed_algos) {
result = -EINVAL;
break;
}
- ima_log_string(ab, "appraise_type", args[0].from);
- if ((strcmp(args[0].from, "imasig")) == 0)
- entry->flags |= IMA_DIGSIG_REQUIRED;
+ entry->allowed_algos =
+ ima_parse_appraise_algos(args[0].from);
+ /* invalid or empty list of algorithms */
+ if (!entry->allowed_algos) {
+ result = -EINVAL;
+ break;
+ }
+
+ entry->flags |= IMA_VALIDATE_ALGOS;
+
+ 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);
@@ -628,10 +1929,26 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
break;
}
}
- if (!result && (entry->action == UNKNOWN))
+ if (!result && !ima_validate_rule(entry))
result = -EINVAL;
- else if (entry->func == MODULE_CHECK)
- ima_appraise |= IMA_APPRAISE_MODULES;
+ 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);
+ }
+
+ /* d-ngv2 template field recommended for unsigned fs-verity digests */
+ if (!result && entry->action == MEASURE &&
+ entry->flags & IMA_VERITY_REQUIRED) {
+ template_desc = entry->template ? entry->template :
+ ima_template_desc_current();
+ check_template_field(template_desc, "d-ngv2",
+ "verity rules should include d-ngv2");
+ }
+
audit_log_format(ab, "res=%d", !result);
audit_log_end(ab);
return result;
@@ -639,26 +1956,25 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
/**
* ima_parse_add_rule - add a rule to ima_policy_rules
- * @rule - ima measurement policy rule
+ * @rule: ima measurement policy rule
*
- * Uses a mutex to protect the policy list from multiple concurrent writers.
+ * 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)
{
- const char *op = "update_policy";
+ static const char op[] = "update_policy";
char *p;
struct ima_rule_entry *entry;
ssize_t result, len;
int audit_info = 0;
- /* Prevent installed policy from changing */
- if (ima_rules != &ima_default_rules) {
- integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL,
- NULL, op, "already exists",
- -EACCES, audit_info);
- return -EACCES;
- }
+ 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) {
@@ -669,43 +1985,400 @@ ssize_t ima_parse_add_rule(char *rule)
INIT_LIST_HEAD(&entry->list);
- p = strsep(&rule, "\n");
- len = strlen(p) + 1;
-
- if (*p == '#') {
- kfree(entry);
- return len;
- }
-
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,
+ NULL, op, "invalid-policy", result,
audit_info);
return result;
}
- mutex_lock(&ima_rules_mutex);
- list_add_tail(&entry->list, &ima_policy_rules);
- mutex_unlock(&ima_rules_mutex);
+ list_add_tail(&entry->list, &ima_temp_rules);
return len;
}
-/* ima_delete_rules called to cleanup invalid policy */
+/**
+ * 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;
+ struct list_head *ima_rules_tmp;
+
+ rcu_read_lock();
+ ima_rules_tmp = rcu_dereference(ima_rules);
+ list_for_each_entry_rcu(entry, ima_rules_tmp, 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_default_rules ||
+ &entry->list == &ima_policy_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]);
+}
+
+static void ima_policy_show_appraise_algos(struct seq_file *m,
+ unsigned int allowed_hashes)
+{
+ int idx, list_size = 0;
+
+ for (idx = 0; idx < HASH_ALGO__LAST; idx++) {
+ if (!(allowed_hashes & (1U << idx)))
+ continue;
+
+ /* only add commas if the list contains multiple entries */
+ if (list_size++)
+ seq_puts(m, ",");
+
+ seq_puts(m, hash_algo_name[idx]);
+ }
+}
+
+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;
- mutex_lock(&ima_rules_mutex);
- list_for_each_entry_safe(entry, tmp, &ima_policy_rules, list) {
- for (i = 0; i < MAX_LSM_RULES; i++)
- kfree(entry->lsm[i].args_p);
+ rcu_read_lock();
- list_del(&entry->list);
- kfree(entry);
+ /* 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 & DONT_AUDIT)
+ seq_puts(m, pt(Opt_dont_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_FS_SUBTYPE) {
+ snprintf(tbuf, sizeof(tbuf), "%s", entry->fs_subtype);
+ seq_printf(m, pt(Opt_fs_subtype), 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_LABEL) {
+ seq_puts(m, "label=");
+ ima_show_rule_opt_list(m, entry->label);
+ 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_GID) {
+ snprintf(tbuf, sizeof(tbuf), "%d", __kgid_val(entry->gid));
+ if (entry->gid_op == &gid_gt)
+ seq_printf(m, pt(Opt_gid_gt), tbuf);
+ else if (entry->gid_op == &gid_lt)
+ seq_printf(m, pt(Opt_gid_lt), tbuf);
+ else
+ seq_printf(m, pt(Opt_gid_eq), tbuf);
+ seq_puts(m, " ");
+ }
+
+ if (entry->flags & IMA_EGID) {
+ snprintf(tbuf, sizeof(tbuf), "%d", __kgid_val(entry->gid));
+ if (entry->gid_op == &gid_gt)
+ seq_printf(m, pt(Opt_egid_gt), tbuf);
+ else if (entry->gid_op == &gid_lt)
+ seq_printf(m, pt(Opt_egid_lt), tbuf);
+ else
+ seq_printf(m, pt(Opt_egid_eq), tbuf);
+ seq_puts(m, " ");
+ }
+
+ if (entry->flags & IMA_FOWNER) {
+ snprintf(tbuf, sizeof(tbuf), "%d", __kuid_val(entry->fowner));
+ if (entry->fowner_op == &vfsuid_gt_kuid)
+ seq_printf(m, pt(Opt_fowner_gt), tbuf);
+ else if (entry->fowner_op == &vfsuid_lt_kuid)
+ seq_printf(m, pt(Opt_fowner_lt), tbuf);
+ else
+ seq_printf(m, pt(Opt_fowner_eq), tbuf);
+ seq_puts(m, " ");
+ }
+
+ if (entry->flags & IMA_FGROUP) {
+ snprintf(tbuf, sizeof(tbuf), "%d", __kgid_val(entry->fgroup));
+ if (entry->fgroup_op == &vfsgid_gt_kgid)
+ seq_printf(m, pt(Opt_fgroup_gt), tbuf);
+ else if (entry->fgroup_op == &vfsgid_lt_kgid)
+ seq_printf(m, pt(Opt_fgroup_lt), tbuf);
+ else
+ seq_printf(m, pt(Opt_fgroup_eq), tbuf);
+ seq_puts(m, " ");
}
- mutex_unlock(&ima_rules_mutex);
+
+ if (entry->flags & IMA_VALIDATE_ALGOS) {
+ seq_puts(m, "appraise_algos=");
+ ima_policy_show_appraise_algos(m, entry->allowed_algos);
+ 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_VERITY_REQUIRED)
+ seq_puts(m, "appraise_type=sigv3 ");
+ else if (entry->flags & IMA_MODSIG_ALLOWED)
+ seq_puts(m, "appraise_type=imasig|modsig ");
+ else
+ seq_puts(m, "appraise_type=imasig ");
+ }
+ if (entry->flags & IMA_VERITY_REQUIRED)
+ seq_puts(m, "digest_type=verity ");
+ 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;
+ struct list_head *ima_rules_tmp;
+
+ 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();
+ ima_rules_tmp = rcu_dereference(ima_rules);
+ list_for_each_entry_rcu(entry, ima_rules_tmp, 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 */
generated by cgit (git 2.34.1) at 2025-12-25 11:25:55 +0000