linux/security/integrity/ima/ima_policy.c

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/*
* Copyright (C) 2008 IBM Corporation
* Author: Mimi Zohar <zohar@us.ibm.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, version 2 of the License.
*
* ima_policy.c
* - initialize default measure policy rules
*
*/
#include <linux/module.h>
#include <linux/list.h>
#include <linux/security.h>
#include <linux/magic.h>
#include <linux/parser.h>
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-24 08:04:11 +00:00
#include <linux/slab.h>
#include "ima.h"
/* flags definitions */
#define IMA_FUNC 0x0001
#define IMA_MASK 0x0002
#define IMA_FSMAGIC 0x0004
#define IMA_UID 0x0008
enum ima_action { UNKNOWN = -1, DONT_MEASURE = 0, MEASURE };
#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
};
struct ima_measure_rule_entry {
struct list_head list;
enum ima_action action;
unsigned int flags;
enum ima_hooks func;
int mask;
unsigned long fsmagic;
uid_t uid;
struct {
void *rule; /* LSM file metadata specific */
int type; /* audit type */
} lsm[MAX_LSM_RULES];
};
IMA: Minimal IMA policy and boot param for TCB IMA policy The IMA TCB policy is dangerous. A normal use can use all of a system's memory (which cannot be freed) simply by building and running lots of executables. The TCB policy is also nearly useless because logging in as root often causes a policy violation when dealing with utmp, thus rendering the measurements meaningless. There is no good fix for this in the kernel. A full TCB policy would need to be loaded in userspace using LSM rule matching to get both a protected and useful system. But, if too little is measured before userspace can load a real policy one again ends up with a meaningless set of measurements. One option would be to put the policy load inside the initrd in order to get it early enough in the boot sequence to be useful, but this runs into trouble with the LSM. For IMA to measure the LSM policy and the LSM policy loading mechanism it needs rules to do so, but we already talked about problems with defaulting to such broad rules.... IMA also depends on the files being measured to be on an FS which implements and supports i_version. Since the only FS with this support (ext4) doesn't even use it by default it seems silly to have any IMA rules by default. This should reduce the performance overhead of IMA to near 0 while still letting users who choose to configure their machine as such to inclue the ima_tcb kernel paramenter and get measurements during boot before they can load a customized, reasonable policy in userspace. Signed-off-by: Eric Paris <eparis@redhat.com> Acked-by: Mimi Zohar <zohar@us.ibm.com> Signed-off-by: James Morris <jmorris@namei.org>
2009-05-21 19:47:06 +00:00
/*
* Without LSM specific knowledge, the default policy can only be
* written in terms of .action, .func, .mask, .fsmagic, and .uid
*/
IMA: Minimal IMA policy and boot param for TCB IMA policy The IMA TCB policy is dangerous. A normal use can use all of a system's memory (which cannot be freed) simply by building and running lots of executables. The TCB policy is also nearly useless because logging in as root often causes a policy violation when dealing with utmp, thus rendering the measurements meaningless. There is no good fix for this in the kernel. A full TCB policy would need to be loaded in userspace using LSM rule matching to get both a protected and useful system. But, if too little is measured before userspace can load a real policy one again ends up with a meaningless set of measurements. One option would be to put the policy load inside the initrd in order to get it early enough in the boot sequence to be useful, but this runs into trouble with the LSM. For IMA to measure the LSM policy and the LSM policy loading mechanism it needs rules to do so, but we already talked about problems with defaulting to such broad rules.... IMA also depends on the files being measured to be on an FS which implements and supports i_version. Since the only FS with this support (ext4) doesn't even use it by default it seems silly to have any IMA rules by default. This should reduce the performance overhead of IMA to near 0 while still letting users who choose to configure their machine as such to inclue the ima_tcb kernel paramenter and get measurements during boot before they can load a customized, reasonable policy in userspace. Signed-off-by: Eric Paris <eparis@redhat.com> Acked-by: Mimi Zohar <zohar@us.ibm.com> Signed-off-by: James Morris <jmorris@namei.org>
2009-05-21 19:47:06 +00:00
/*
* The minimum rule set to allow for full TCB coverage. Measures all files
* opened or mmap for exec and everything read by root. Dangerous because
* normal users can easily run the machine out of memory simply building
* and running executables.
*/
static struct ima_measure_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 = SECURITYFS_MAGIC,.flags = IMA_FSMAGIC},
{.action = DONT_MEASURE,.fsmagic = SELINUX_MAGIC,.flags = IMA_FSMAGIC},
{.action = MEASURE,.func = FILE_MMAP,.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 = 0,
IMA: Minimal IMA policy and boot param for TCB IMA policy The IMA TCB policy is dangerous. A normal use can use all of a system's memory (which cannot be freed) simply by building and running lots of executables. The TCB policy is also nearly useless because logging in as root often causes a policy violation when dealing with utmp, thus rendering the measurements meaningless. There is no good fix for this in the kernel. A full TCB policy would need to be loaded in userspace using LSM rule matching to get both a protected and useful system. But, if too little is measured before userspace can load a real policy one again ends up with a meaningless set of measurements. One option would be to put the policy load inside the initrd in order to get it early enough in the boot sequence to be useful, but this runs into trouble with the LSM. For IMA to measure the LSM policy and the LSM policy loading mechanism it needs rules to do so, but we already talked about problems with defaulting to such broad rules.... IMA also depends on the files being measured to be on an FS which implements and supports i_version. Since the only FS with this support (ext4) doesn't even use it by default it seems silly to have any IMA rules by default. This should reduce the performance overhead of IMA to near 0 while still letting users who choose to configure their machine as such to inclue the ima_tcb kernel paramenter and get measurements during boot before they can load a customized, reasonable policy in userspace. Signed-off-by: Eric Paris <eparis@redhat.com> Acked-by: Mimi Zohar <zohar@us.ibm.com> Signed-off-by: James Morris <jmorris@namei.org>
2009-05-21 19:47:06 +00:00
.flags = IMA_FUNC | IMA_MASK | IMA_UID},
};
static LIST_HEAD(measure_default_rules);
static LIST_HEAD(measure_policy_rules);
static struct list_head *ima_measure;
static DEFINE_MUTEX(ima_measure_mutex);
IMA: Minimal IMA policy and boot param for TCB IMA policy The IMA TCB policy is dangerous. A normal use can use all of a system's memory (which cannot be freed) simply by building and running lots of executables. The TCB policy is also nearly useless because logging in as root often causes a policy violation when dealing with utmp, thus rendering the measurements meaningless. There is no good fix for this in the kernel. A full TCB policy would need to be loaded in userspace using LSM rule matching to get both a protected and useful system. But, if too little is measured before userspace can load a real policy one again ends up with a meaningless set of measurements. One option would be to put the policy load inside the initrd in order to get it early enough in the boot sequence to be useful, but this runs into trouble with the LSM. For IMA to measure the LSM policy and the LSM policy loading mechanism it needs rules to do so, but we already talked about problems with defaulting to such broad rules.... IMA also depends on the files being measured to be on an FS which implements and supports i_version. Since the only FS with this support (ext4) doesn't even use it by default it seems silly to have any IMA rules by default. This should reduce the performance overhead of IMA to near 0 while still letting users who choose to configure their machine as such to inclue the ima_tcb kernel paramenter and get measurements during boot before they can load a customized, reasonable policy in userspace. Signed-off-by: Eric Paris <eparis@redhat.com> Acked-by: Mimi Zohar <zohar@us.ibm.com> Signed-off-by: James Morris <jmorris@namei.org>
2009-05-21 19:47:06 +00:00
static bool ima_use_tcb __initdata;
static int __init default_policy_setup(char *str)
{
ima_use_tcb = 1;
return 1;
}
__setup("ima_tcb", default_policy_setup);
/**
* ima_match_rules - determine whether an inode matches the measure rule.
* @rule: a pointer to a rule
* @inode: a pointer to an inode
* @func: LIM hook identifier
* @mask: requested action (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC)
*
* Returns true on rule match, false on failure.
*/
static bool ima_match_rules(struct ima_measure_rule_entry *rule,
struct inode *inode, enum ima_hooks func, int mask)
{
struct task_struct *tsk = current;
int i;
if ((rule->flags & IMA_FUNC) && rule->func != func)
return false;
if ((rule->flags & IMA_MASK) && rule->mask != mask)
return false;
if ((rule->flags & IMA_FSMAGIC)
&& rule->fsmagic != inode->i_sb->s_magic)
return false;
if ((rule->flags & IMA_UID) && rule->uid != tsk->cred->uid)
return false;
for (i = 0; i < MAX_LSM_RULES; i++) {
int rc = 0;
u32 osid, sid;
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,
NULL);
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);
default:
break;
}
if (!rc)
return false;
}
return true;
}
/**
* ima_match_policy - decision based on LSM and other conditions
* @inode: pointer to an inode for which the policy decision is being made
* @func: IMA hook identifier
* @mask: requested action (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC)
*
* 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.)
*/
int ima_match_policy(struct inode *inode, enum ima_hooks func, int mask)
{
struct ima_measure_rule_entry *entry;
list_for_each_entry(entry, ima_measure, list) {
bool rc;
rc = ima_match_rules(entry, inode, func, mask);
if (rc)
return entry->action;
}
return 0;
}
/**
* ima_init_policy - initialize the default measure rules.
*
* ima_measure points to either the measure_default_rules or the
* the new measure_policy_rules.
*/
void __init ima_init_policy(void)
{
IMA: Minimal IMA policy and boot param for TCB IMA policy The IMA TCB policy is dangerous. A normal use can use all of a system's memory (which cannot be freed) simply by building and running lots of executables. The TCB policy is also nearly useless because logging in as root often causes a policy violation when dealing with utmp, thus rendering the measurements meaningless. There is no good fix for this in the kernel. A full TCB policy would need to be loaded in userspace using LSM rule matching to get both a protected and useful system. But, if too little is measured before userspace can load a real policy one again ends up with a meaningless set of measurements. One option would be to put the policy load inside the initrd in order to get it early enough in the boot sequence to be useful, but this runs into trouble with the LSM. For IMA to measure the LSM policy and the LSM policy loading mechanism it needs rules to do so, but we already talked about problems with defaulting to such broad rules.... IMA also depends on the files being measured to be on an FS which implements and supports i_version. Since the only FS with this support (ext4) doesn't even use it by default it seems silly to have any IMA rules by default. This should reduce the performance overhead of IMA to near 0 while still letting users who choose to configure their machine as such to inclue the ima_tcb kernel paramenter and get measurements during boot before they can load a customized, reasonable policy in userspace. Signed-off-by: Eric Paris <eparis@redhat.com> Acked-by: Mimi Zohar <zohar@us.ibm.com> Signed-off-by: James Morris <jmorris@namei.org>
2009-05-21 19:47:06 +00:00
int i, entries;
/* if !ima_use_tcb set entries = 0 so we load NO default rules */
if (ima_use_tcb)
entries = ARRAY_SIZE(default_rules);
else
entries = 0;
IMA: Minimal IMA policy and boot param for TCB IMA policy The IMA TCB policy is dangerous. A normal use can use all of a system's memory (which cannot be freed) simply by building and running lots of executables. The TCB policy is also nearly useless because logging in as root often causes a policy violation when dealing with utmp, thus rendering the measurements meaningless. There is no good fix for this in the kernel. A full TCB policy would need to be loaded in userspace using LSM rule matching to get both a protected and useful system. But, if too little is measured before userspace can load a real policy one again ends up with a meaningless set of measurements. One option would be to put the policy load inside the initrd in order to get it early enough in the boot sequence to be useful, but this runs into trouble with the LSM. For IMA to measure the LSM policy and the LSM policy loading mechanism it needs rules to do so, but we already talked about problems with defaulting to such broad rules.... IMA also depends on the files being measured to be on an FS which implements and supports i_version. Since the only FS with this support (ext4) doesn't even use it by default it seems silly to have any IMA rules by default. This should reduce the performance overhead of IMA to near 0 while still letting users who choose to configure their machine as such to inclue the ima_tcb kernel paramenter and get measurements during boot before they can load a customized, reasonable policy in userspace. Signed-off-by: Eric Paris <eparis@redhat.com> Acked-by: Mimi Zohar <zohar@us.ibm.com> Signed-off-by: James Morris <jmorris@namei.org>
2009-05-21 19:47:06 +00:00
for (i = 0; i < entries; i++)
list_add_tail(&default_rules[i].list, &measure_default_rules);
ima_measure = &measure_default_rules;
}
/**
* 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.
*/
void ima_update_policy(void)
{
const char *op = "policy_update";
const char *cause = "already exists";
int result = 1;
int audit_info = 0;
if (ima_measure == &measure_default_rules) {
ima_measure = &measure_policy_rules;
cause = "complete";
result = 0;
}
integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL,
NULL, op, cause, result, audit_info);
}
enum {
Opt_err = -1,
Opt_measure = 1, Opt_dont_measure,
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
};
static match_table_t policy_tokens = {
{Opt_measure, "measure"},
{Opt_dont_measure, "dont_measure"},
{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_uid, "uid=%s"},
{Opt_err, NULL}
};
static int ima_lsm_rule_init(struct ima_measure_rule_entry *entry,
char *args, int lsm_rule, int audit_type)
{
int result;
if (entry->lsm[lsm_rule].rule)
return -EINVAL;
entry->lsm[lsm_rule].type = audit_type;
result = security_filter_rule_init(entry->lsm[lsm_rule].type,
Audit_equal, args,
&entry->lsm[lsm_rule].rule);
return result;
}
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, " ");
}
static int ima_parse_rule(char *rule, struct ima_measure_rule_entry *entry)
{
struct audit_buffer *ab;
char *p;
int result = 0;
ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_INTEGRITY_RULE);
entry->uid = -1;
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_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, "FILE_MMAP") == 0)
entry->func = FILE_MMAP;
else if (strcmp(args[0].from, "BPRM_CHECK") == 0)
entry->func = BPRM_CHECK;
else
result = -EINVAL;
if (!result)
entry->flags |= IMA_FUNC;
break;
case Opt_mask:
ima_log_string(ab, "mask", args[0].from);
if (entry->mask)
result = -EINVAL;
if ((strcmp(args[0].from, "MAY_EXEC")) == 0)
entry->mask = MAY_EXEC;
else if (strcmp(args[0].from, "MAY_WRITE") == 0)
entry->mask = MAY_WRITE;
else if (strcmp(args[0].from, "MAY_READ") == 0)
entry->mask = MAY_READ;
else if (strcmp(args[0].from, "MAY_APPEND") == 0)
entry->mask = MAY_APPEND;
else
result = -EINVAL;
if (!result)
entry->flags |= IMA_MASK;
break;
case Opt_fsmagic:
ima_log_string(ab, "fsmagic", args[0].from);
if (entry->fsmagic) {
result = -EINVAL;
break;
}
result = strict_strtoul(args[0].from, 16,
&entry->fsmagic);
if (!result)
entry->flags |= IMA_FSMAGIC;
break;
case Opt_uid:
ima_log_string(ab, "uid", args[0].from);
if (entry->uid != -1) {
result = -EINVAL;
break;
}
result = strict_strtoul(args[0].from, 10, &lnum);
if (!result) {
entry->uid = (uid_t) lnum;
if (entry->uid != lnum)
result = -EINVAL;
else
entry->flags |= IMA_UID;
}
break;
case Opt_obj_user:
ima_log_string(ab, "obj_user", args[0].from);
result = ima_lsm_rule_init(entry, args[0].from,
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[0].from,
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[0].from,
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[0].from,
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[0].from,
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[0].from,
LSM_SUBJ_TYPE,
AUDIT_SUBJ_TYPE);
break;
case Opt_err:
ima_log_string(ab, "UNKNOWN", p);
result = -EINVAL;
break;
}
}
if (!result && (entry->action == UNKNOWN))
result = -EINVAL;
audit_log_format(ab, "res=%d", !!result);
audit_log_end(ab);
return result;
}
/**
* ima_parse_add_rule - add a rule to measure_policy_rules
* @rule - ima measurement policy rule
*
* Uses a mutex to protect the policy list from multiple concurrent writers.
* 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";
char *p;
struct ima_measure_rule_entry *entry;
ssize_t result, len;
int audit_info = 0;
/* Prevent installed policy from changing */
if (ima_measure != &measure_default_rules) {
integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL,
NULL, op, "already exists",
-EACCES, audit_info);
return -EACCES;
}
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);
p = strsep(&rule, "\n");
len = strlen(p) + 1;
if (*p == '#') {
kfree(entry);
return len;
}
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;
}
mutex_lock(&ima_measure_mutex);
list_add_tail(&entry->list, &measure_policy_rules);
mutex_unlock(&ima_measure_mutex);
return len;
}
/* ima_delete_rules called to cleanup invalid policy */
void ima_delete_rules(void)
{
struct ima_measure_rule_entry *entry, *tmp;
mutex_lock(&ima_measure_mutex);
list_for_each_entry_safe(entry, tmp, &measure_policy_rules, list) {
list_del(&entry->list);
kfree(entry);
}
mutex_unlock(&ima_measure_mutex);
}