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![Thiago Jung Bauermann](/assets/img/avatar_default.png)
Introduce the modsig keyword to the IMA policy syntax to specify that a given hook should expect the file to have the IMA signature appended to it. Here is how it can be used in a rule: appraise func=KEXEC_KERNEL_CHECK appraise_type=imasig|modsig With this rule, IMA will accept either a signature stored in the extended attribute or an appended signature. For now, the rule above will behave exactly the same as if appraise_type=imasig was specified. The actual modsig implementation will be introduced separately. Suggested-by: Mimi Zohar <zohar@linux.ibm.com> Signed-off-by: Thiago Jung Bauermann <bauerman@linux.ibm.com> Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
1468 lines
39 KiB
C
1468 lines
39 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright (C) 2008 IBM Corporation
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* Author: Mimi Zohar <zohar@us.ibm.com>
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*
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* ima_policy.c
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* - initialize default measure policy rules
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*/
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#include <linux/init.h>
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#include <linux/list.h>
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#include <linux/fs.h>
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#include <linux/security.h>
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#include <linux/magic.h>
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#include <linux/parser.h>
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#include <linux/slab.h>
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#include <linux/rculist.h>
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#include <linux/genhd.h>
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#include <linux/seq_file.h>
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#include <linux/ima.h>
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#include "ima.h"
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/* flags definitions */
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#define IMA_FUNC 0x0001
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#define IMA_MASK 0x0002
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#define IMA_FSMAGIC 0x0004
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#define IMA_UID 0x0008
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#define IMA_FOWNER 0x0010
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#define IMA_FSUUID 0x0020
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#define IMA_INMASK 0x0040
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#define IMA_EUID 0x0080
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#define IMA_PCR 0x0100
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#define IMA_FSNAME 0x0200
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#define UNKNOWN 0
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#define MEASURE 0x0001 /* same as IMA_MEASURE */
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#define DONT_MEASURE 0x0002
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#define APPRAISE 0x0004 /* same as IMA_APPRAISE */
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#define DONT_APPRAISE 0x0008
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#define AUDIT 0x0040
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#define HASH 0x0100
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#define DONT_HASH 0x0200
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#define INVALID_PCR(a) (((a) < 0) || \
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(a) >= (FIELD_SIZEOF(struct integrity_iint_cache, measured_pcrs) * 8))
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int ima_policy_flag;
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static int temp_ima_appraise;
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static int build_ima_appraise __ro_after_init;
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#define MAX_LSM_RULES 6
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enum lsm_rule_types { LSM_OBJ_USER, LSM_OBJ_ROLE, LSM_OBJ_TYPE,
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LSM_SUBJ_USER, LSM_SUBJ_ROLE, LSM_SUBJ_TYPE
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};
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enum policy_types { ORIGINAL_TCB = 1, DEFAULT_TCB };
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enum policy_rule_list { IMA_DEFAULT_POLICY = 1, IMA_CUSTOM_POLICY };
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struct ima_rule_entry {
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struct list_head list;
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int action;
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unsigned int flags;
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enum ima_hooks func;
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int mask;
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unsigned long fsmagic;
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uuid_t fsuuid;
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kuid_t uid;
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kuid_t fowner;
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bool (*uid_op)(kuid_t, kuid_t); /* Handlers for operators */
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bool (*fowner_op)(kuid_t, kuid_t); /* uid_eq(), uid_gt(), uid_lt() */
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int pcr;
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struct {
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void *rule; /* LSM file metadata specific */
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void *args_p; /* audit value */
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int type; /* audit type */
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} lsm[MAX_LSM_RULES];
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char *fsname;
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struct ima_template_desc *template;
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};
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/*
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* Without LSM specific knowledge, the default policy can only be
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* written in terms of .action, .func, .mask, .fsmagic, .uid, and .fowner
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*/
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/*
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* The minimum rule set to allow for full TCB coverage. Measures all files
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* opened or mmap for exec and everything read by root. Dangerous because
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* normal users can easily run the machine out of memory simply building
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* and running executables.
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*/
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static struct ima_rule_entry dont_measure_rules[] __ro_after_init = {
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{.action = DONT_MEASURE, .fsmagic = PROC_SUPER_MAGIC, .flags = IMA_FSMAGIC},
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{.action = DONT_MEASURE, .fsmagic = SYSFS_MAGIC, .flags = IMA_FSMAGIC},
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{.action = DONT_MEASURE, .fsmagic = DEBUGFS_MAGIC, .flags = IMA_FSMAGIC},
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{.action = DONT_MEASURE, .fsmagic = TMPFS_MAGIC, .flags = IMA_FSMAGIC},
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{.action = DONT_MEASURE, .fsmagic = DEVPTS_SUPER_MAGIC, .flags = IMA_FSMAGIC},
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{.action = DONT_MEASURE, .fsmagic = BINFMTFS_MAGIC, .flags = IMA_FSMAGIC},
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{.action = DONT_MEASURE, .fsmagic = SECURITYFS_MAGIC, .flags = IMA_FSMAGIC},
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{.action = DONT_MEASURE, .fsmagic = SELINUX_MAGIC, .flags = IMA_FSMAGIC},
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{.action = DONT_MEASURE, .fsmagic = SMACK_MAGIC, .flags = IMA_FSMAGIC},
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{.action = DONT_MEASURE, .fsmagic = CGROUP_SUPER_MAGIC,
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.flags = IMA_FSMAGIC},
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{.action = DONT_MEASURE, .fsmagic = CGROUP2_SUPER_MAGIC,
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.flags = IMA_FSMAGIC},
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{.action = DONT_MEASURE, .fsmagic = NSFS_MAGIC, .flags = IMA_FSMAGIC},
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{.action = DONT_MEASURE, .fsmagic = EFIVARFS_MAGIC, .flags = IMA_FSMAGIC}
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};
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static struct ima_rule_entry original_measurement_rules[] __ro_after_init = {
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{.action = MEASURE, .func = MMAP_CHECK, .mask = MAY_EXEC,
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.flags = IMA_FUNC | IMA_MASK},
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{.action = MEASURE, .func = BPRM_CHECK, .mask = MAY_EXEC,
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.flags = IMA_FUNC | IMA_MASK},
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{.action = MEASURE, .func = FILE_CHECK, .mask = MAY_READ,
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.uid = GLOBAL_ROOT_UID, .uid_op = &uid_eq,
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.flags = IMA_FUNC | IMA_MASK | IMA_UID},
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{.action = MEASURE, .func = MODULE_CHECK, .flags = IMA_FUNC},
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{.action = MEASURE, .func = FIRMWARE_CHECK, .flags = IMA_FUNC},
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};
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static struct ima_rule_entry default_measurement_rules[] __ro_after_init = {
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{.action = MEASURE, .func = MMAP_CHECK, .mask = MAY_EXEC,
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.flags = IMA_FUNC | IMA_MASK},
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{.action = MEASURE, .func = BPRM_CHECK, .mask = MAY_EXEC,
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.flags = IMA_FUNC | IMA_MASK},
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{.action = MEASURE, .func = FILE_CHECK, .mask = MAY_READ,
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.uid = GLOBAL_ROOT_UID, .uid_op = &uid_eq,
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.flags = IMA_FUNC | IMA_INMASK | IMA_EUID},
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{.action = MEASURE, .func = FILE_CHECK, .mask = MAY_READ,
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.uid = GLOBAL_ROOT_UID, .uid_op = &uid_eq,
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.flags = IMA_FUNC | IMA_INMASK | IMA_UID},
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{.action = MEASURE, .func = MODULE_CHECK, .flags = IMA_FUNC},
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{.action = MEASURE, .func = FIRMWARE_CHECK, .flags = IMA_FUNC},
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{.action = MEASURE, .func = POLICY_CHECK, .flags = IMA_FUNC},
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};
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static struct ima_rule_entry default_appraise_rules[] __ro_after_init = {
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{.action = DONT_APPRAISE, .fsmagic = PROC_SUPER_MAGIC, .flags = IMA_FSMAGIC},
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{.action = DONT_APPRAISE, .fsmagic = SYSFS_MAGIC, .flags = IMA_FSMAGIC},
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{.action = DONT_APPRAISE, .fsmagic = DEBUGFS_MAGIC, .flags = IMA_FSMAGIC},
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{.action = DONT_APPRAISE, .fsmagic = TMPFS_MAGIC, .flags = IMA_FSMAGIC},
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{.action = DONT_APPRAISE, .fsmagic = RAMFS_MAGIC, .flags = IMA_FSMAGIC},
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{.action = DONT_APPRAISE, .fsmagic = DEVPTS_SUPER_MAGIC, .flags = IMA_FSMAGIC},
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{.action = DONT_APPRAISE, .fsmagic = BINFMTFS_MAGIC, .flags = IMA_FSMAGIC},
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{.action = DONT_APPRAISE, .fsmagic = SECURITYFS_MAGIC, .flags = IMA_FSMAGIC},
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{.action = DONT_APPRAISE, .fsmagic = SELINUX_MAGIC, .flags = IMA_FSMAGIC},
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{.action = DONT_APPRAISE, .fsmagic = SMACK_MAGIC, .flags = IMA_FSMAGIC},
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{.action = DONT_APPRAISE, .fsmagic = NSFS_MAGIC, .flags = IMA_FSMAGIC},
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{.action = DONT_APPRAISE, .fsmagic = EFIVARFS_MAGIC, .flags = IMA_FSMAGIC},
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{.action = DONT_APPRAISE, .fsmagic = CGROUP_SUPER_MAGIC, .flags = IMA_FSMAGIC},
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{.action = DONT_APPRAISE, .fsmagic = CGROUP2_SUPER_MAGIC, .flags = IMA_FSMAGIC},
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#ifdef CONFIG_IMA_WRITE_POLICY
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{.action = APPRAISE, .func = POLICY_CHECK,
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.flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
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#endif
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#ifndef CONFIG_IMA_APPRAISE_SIGNED_INIT
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{.action = APPRAISE, .fowner = GLOBAL_ROOT_UID, .fowner_op = &uid_eq,
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.flags = IMA_FOWNER},
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#else
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/* force signature */
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{.action = APPRAISE, .fowner = GLOBAL_ROOT_UID, .fowner_op = &uid_eq,
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.flags = IMA_FOWNER | IMA_DIGSIG_REQUIRED},
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#endif
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};
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static struct ima_rule_entry build_appraise_rules[] __ro_after_init = {
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#ifdef CONFIG_IMA_APPRAISE_REQUIRE_MODULE_SIGS
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{.action = APPRAISE, .func = MODULE_CHECK,
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.flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
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#endif
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#ifdef CONFIG_IMA_APPRAISE_REQUIRE_FIRMWARE_SIGS
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{.action = APPRAISE, .func = FIRMWARE_CHECK,
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.flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
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#endif
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#ifdef CONFIG_IMA_APPRAISE_REQUIRE_KEXEC_SIGS
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{.action = APPRAISE, .func = KEXEC_KERNEL_CHECK,
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.flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
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#endif
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#ifdef CONFIG_IMA_APPRAISE_REQUIRE_POLICY_SIGS
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{.action = APPRAISE, .func = POLICY_CHECK,
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.flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
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#endif
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};
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static struct ima_rule_entry secure_boot_rules[] __ro_after_init = {
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{.action = APPRAISE, .func = MODULE_CHECK,
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.flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
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{.action = APPRAISE, .func = FIRMWARE_CHECK,
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.flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
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{.action = APPRAISE, .func = KEXEC_KERNEL_CHECK,
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.flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
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{.action = APPRAISE, .func = POLICY_CHECK,
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.flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
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};
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/* An array of architecture specific rules */
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static struct ima_rule_entry *arch_policy_entry __ro_after_init;
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static LIST_HEAD(ima_default_rules);
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static LIST_HEAD(ima_policy_rules);
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static LIST_HEAD(ima_temp_rules);
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static struct list_head *ima_rules;
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static int ima_policy __initdata;
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static int __init default_measure_policy_setup(char *str)
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{
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if (ima_policy)
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return 1;
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ima_policy = ORIGINAL_TCB;
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return 1;
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}
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__setup("ima_tcb", default_measure_policy_setup);
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static bool ima_use_appraise_tcb __initdata;
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static bool ima_use_secure_boot __initdata;
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static bool ima_fail_unverifiable_sigs __ro_after_init;
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static int __init policy_setup(char *str)
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{
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char *p;
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while ((p = strsep(&str, " |\n")) != NULL) {
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if (*p == ' ')
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continue;
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if ((strcmp(p, "tcb") == 0) && !ima_policy)
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ima_policy = DEFAULT_TCB;
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else if (strcmp(p, "appraise_tcb") == 0)
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ima_use_appraise_tcb = true;
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else if (strcmp(p, "secure_boot") == 0)
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ima_use_secure_boot = true;
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else if (strcmp(p, "fail_securely") == 0)
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ima_fail_unverifiable_sigs = true;
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}
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return 1;
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}
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__setup("ima_policy=", policy_setup);
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static int __init default_appraise_policy_setup(char *str)
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{
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ima_use_appraise_tcb = true;
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return 1;
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}
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__setup("ima_appraise_tcb", default_appraise_policy_setup);
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static void ima_lsm_free_rule(struct ima_rule_entry *entry)
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{
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int i;
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for (i = 0; i < MAX_LSM_RULES; i++) {
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kfree(entry->lsm[i].rule);
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kfree(entry->lsm[i].args_p);
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}
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kfree(entry);
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}
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static struct ima_rule_entry *ima_lsm_copy_rule(struct ima_rule_entry *entry)
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{
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struct ima_rule_entry *nentry;
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int i, result;
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nentry = kmalloc(sizeof(*nentry), GFP_KERNEL);
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if (!nentry)
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return NULL;
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/*
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* Immutable elements are copied over as pointers and data; only
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* lsm rules can change
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*/
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memcpy(nentry, entry, sizeof(*nentry));
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memset(nentry->lsm, 0, FIELD_SIZEOF(struct ima_rule_entry, lsm));
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for (i = 0; i < MAX_LSM_RULES; i++) {
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if (!entry->lsm[i].rule)
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continue;
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nentry->lsm[i].type = entry->lsm[i].type;
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nentry->lsm[i].args_p = kstrdup(entry->lsm[i].args_p,
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GFP_KERNEL);
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if (!nentry->lsm[i].args_p)
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goto out_err;
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result = security_filter_rule_init(nentry->lsm[i].type,
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Audit_equal,
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nentry->lsm[i].args_p,
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&nentry->lsm[i].rule);
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if (result == -EINVAL)
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pr_warn("ima: rule for LSM \'%d\' is undefined\n",
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entry->lsm[i].type);
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}
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return nentry;
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out_err:
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ima_lsm_free_rule(nentry);
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return NULL;
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}
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static int ima_lsm_update_rule(struct ima_rule_entry *entry)
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{
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struct ima_rule_entry *nentry;
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nentry = ima_lsm_copy_rule(entry);
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if (!nentry)
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return -ENOMEM;
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list_replace_rcu(&entry->list, &nentry->list);
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synchronize_rcu();
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ima_lsm_free_rule(entry);
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return 0;
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}
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/*
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* The LSM policy can be reloaded, leaving the IMA LSM based rules referring
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* to the old, stale LSM policy. Update the IMA LSM based rules to reflect
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* the reloaded LSM policy.
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*/
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static void ima_lsm_update_rules(void)
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{
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struct ima_rule_entry *entry, *e;
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int i, result, needs_update;
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list_for_each_entry_safe(entry, e, &ima_policy_rules, list) {
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needs_update = 0;
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for (i = 0; i < MAX_LSM_RULES; i++) {
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if (entry->lsm[i].rule) {
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needs_update = 1;
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break;
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}
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}
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if (!needs_update)
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continue;
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result = ima_lsm_update_rule(entry);
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if (result) {
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pr_err("ima: lsm rule update error %d\n",
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result);
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return;
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}
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}
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}
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int ima_lsm_policy_change(struct notifier_block *nb, unsigned long event,
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void *lsm_data)
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{
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if (event != LSM_POLICY_CHANGE)
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return NOTIFY_DONE;
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ima_lsm_update_rules();
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return NOTIFY_OK;
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}
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/**
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* ima_match_rules - determine whether an inode matches the measure rule.
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* @rule: a pointer to a rule
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* @inode: a pointer to an inode
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* @cred: a pointer to a credentials structure for user validation
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* @secid: the secid of the task to be validated
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* @func: LIM hook identifier
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* @mask: requested action (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC)
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*
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* Returns true on rule match, false on failure.
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*/
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static bool ima_match_rules(struct ima_rule_entry *rule, struct inode *inode,
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const struct cred *cred, u32 secid,
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enum ima_hooks func, int mask)
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{
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int i;
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if (func == KEXEC_CMDLINE) {
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if ((rule->flags & IMA_FUNC) && (rule->func == func))
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return true;
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return false;
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}
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if ((rule->flags & IMA_FUNC) &&
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(rule->func != func && func != POST_SETATTR))
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return false;
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if ((rule->flags & IMA_MASK) &&
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(rule->mask != mask && func != POST_SETATTR))
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return false;
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if ((rule->flags & IMA_INMASK) &&
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(!(rule->mask & mask) && func != POST_SETATTR))
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return false;
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if ((rule->flags & IMA_FSMAGIC)
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&& rule->fsmagic != inode->i_sb->s_magic)
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return false;
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if ((rule->flags & IMA_FSNAME)
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&& strcmp(rule->fsname, inode->i_sb->s_type->name))
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return false;
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if ((rule->flags & IMA_FSUUID) &&
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!uuid_equal(&rule->fsuuid, &inode->i_sb->s_uuid))
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return false;
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if ((rule->flags & IMA_UID) && !rule->uid_op(cred->uid, rule->uid))
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return false;
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if (rule->flags & IMA_EUID) {
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if (has_capability_noaudit(current, CAP_SETUID)) {
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if (!rule->uid_op(cred->euid, rule->uid)
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&& !rule->uid_op(cred->suid, rule->uid)
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&& !rule->uid_op(cred->uid, rule->uid))
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return false;
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} else if (!rule->uid_op(cred->euid, rule->uid))
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return false;
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}
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if ((rule->flags & IMA_FOWNER) &&
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!rule->fowner_op(inode->i_uid, rule->fowner))
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return false;
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for (i = 0; i < MAX_LSM_RULES; i++) {
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int rc = 0;
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|
u32 osid;
|
|
|
|
if (!rule->lsm[i].rule)
|
|
continue;
|
|
|
|
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);
|
|
break;
|
|
case LSM_SUBJ_USER:
|
|
case LSM_SUBJ_ROLE:
|
|
case LSM_SUBJ_TYPE:
|
|
rc = security_filter_rule_match(secid,
|
|
rule->lsm[i].type,
|
|
Audit_equal,
|
|
rule->lsm[i].rule);
|
|
default:
|
|
break;
|
|
}
|
|
if (!rc)
|
|
return false;
|
|
}
|
|
return true;
|
|
}
|
|
|
|
/*
|
|
* 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)
|
|
* @pcr: set the pcr to extend
|
|
* @template_desc: the template that should be used for this rule
|
|
*
|
|
* 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)
|
|
{
|
|
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))
|
|
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) {
|
|
temp_ima_appraise |= ima_appraise_flag(entries[i].func);
|
|
if (entries[i].func == POLICY_CHECK)
|
|
temp_ima_appraise |= IMA_APPRAISE_POLICY;
|
|
}
|
|
}
|
|
}
|
|
|
|
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);
|
|
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_rules = &ima_default_rules;
|
|
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();
|
|
}
|
|
|
|
/* 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_permit_directio,
|
|
Opt_pcr, Opt_template, 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_permit_directio, "permit_directio"},
|
|
{Opt_pcr, "pcr=%s"},
|
|
{Opt_template, "template=%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 = security_filter_rule_init(entry->lsm[lsm_rule].type,
|
|
Audit_equal,
|
|
entry->lsm[lsm_rule].args_p,
|
|
&entry->lsm[lsm_rule].rule);
|
|
if (!entry->lsm[lsm_rule].rule) {
|
|
kfree(entry->lsm[lsm_rule].args_p);
|
|
return -EINVAL;
|
|
}
|
|
|
|
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);
|
|
}
|
|
|
|
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
|
|
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_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;
|
|
/* fall through */
|
|
case Opt_uid_lt:
|
|
case Opt_euid_lt:
|
|
if ((token == Opt_uid_lt) || (token == Opt_euid_lt))
|
|
entry->uid_op = &uid_lt;
|
|
/* fall through */
|
|
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;
|
|
/* fall through */
|
|
case Opt_fowner_lt:
|
|
if (token == Opt_fowner_lt)
|
|
entry->fowner_op = &uid_lt;
|
|
/* fall through */
|
|
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:
|
|
if (entry->action != APPRAISE) {
|
|
result = -EINVAL;
|
|
break;
|
|
}
|
|
|
|
ima_log_string(ab, "appraise_type", args[0].from);
|
|
if ((strcmp(args[0].from, "imasig")) == 0)
|
|
entry->flags |= IMA_DIGSIG_REQUIRED;
|
|
else if (ima_hook_supports_modsig(entry->func) &&
|
|
strcmp(args[0].from, "imasig|modsig") == 0)
|
|
entry->flags |= IMA_DIGSIG_REQUIRED |
|
|
IMA_MODSIG_ALLOWED;
|
|
else
|
|
result = -EINVAL;
|
|
break;
|
|
case Opt_permit_directio:
|
|
entry->flags |= IMA_PERMIT_DIRECTIO;
|
|
break;
|
|
case Opt_pcr:
|
|
if (entry->action != MEASURE) {
|
|
result = -EINVAL;
|
|
break;
|
|
}
|
|
ima_log_string(ab, "pcr", args[0].from);
|
|
|
|
result = kstrtoint(args[0].from, 10, &entry->pcr);
|
|
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 && (entry->action == UNKNOWN))
|
|
result = -EINVAL;
|
|
else if (entry->action == APPRAISE)
|
|
temp_ima_appraise |= ima_appraise_flag(entry->func);
|
|
|
|
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) {
|
|
kfree(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;
|
|
int i;
|
|
|
|
temp_ima_appraise = 0;
|
|
list_for_each_entry_safe(entry, tmp, &ima_temp_rules, list) {
|
|
for (i = 0; i < MAX_LSM_RULES; i++)
|
|
kfree(entry->lsm[i].args_p);
|
|
|
|
list_del(&entry->list);
|
|
kfree(entry);
|
|
}
|
|
}
|
|
|
|
#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"
|
|
};
|
|
|
|
#define __ima_hook_stringify(str) (#str),
|
|
|
|
static const char *const func_tokens[] = {
|
|
__ima_hooks(__ima_hook_stringify)
|
|
};
|
|
|
|
void *ima_policy_start(struct seq_file *m, loff_t *pos)
|
|
{
|
|
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);
|
|
}
|
|
|
|
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();
|
|
|
|
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_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),
|
|
(char *)entry->lsm[i].args_p);
|
|
break;
|
|
case LSM_OBJ_ROLE:
|
|
seq_printf(m, pt(Opt_obj_role),
|
|
(char *)entry->lsm[i].args_p);
|
|
break;
|
|
case LSM_OBJ_TYPE:
|
|
seq_printf(m, pt(Opt_obj_type),
|
|
(char *)entry->lsm[i].args_p);
|
|
break;
|
|
case LSM_SUBJ_USER:
|
|
seq_printf(m, pt(Opt_subj_user),
|
|
(char *)entry->lsm[i].args_p);
|
|
break;
|
|
case LSM_SUBJ_ROLE:
|
|
seq_printf(m, pt(Opt_subj_role),
|
|
(char *)entry->lsm[i].args_p);
|
|
break;
|
|
case LSM_SUBJ_TYPE:
|
|
seq_printf(m, pt(Opt_subj_type),
|
|
(char *)entry->lsm[i].args_p);
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
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_PERMIT_DIRECTIO)
|
|
seq_puts(m, "permit_directio ");
|
|
rcu_read_unlock();
|
|
seq_puts(m, "\n");
|
|
return 0;
|
|
}
|
|
#endif /* CONFIG_IMA_READ_POLICY */
|