// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2005,2006,2007,2008 IBM Corporation
*
* Authors:
* Kylene Hall <[email protected]>
* Reiner Sailer <[email protected]>
* Mimi Zohar <[email protected]>
*
* File: ima_fs.c
* implemenents security file system for reporting
* current measurement list and IMA statistics
*/
#include <linux/fcntl.h>
#include <linux/kernel_read_file.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/seq_file.h>
#include <linux/rculist.h>
#include <linux/rcupdate.h>
#include <linux/parser.h>
#include <linux/vmalloc.h>
#include "ima.h"
static DEFINE_MUTEX(ima_write_mutex);
bool ima_canonical_fmt;
static int __init default_canonical_fmt_setup(char *str)
{
#ifdef __BIG_ENDIAN
ima_canonical_fmt = true;
#endif
return 1;
}
__setup("ima_canonical_fmt", default_canonical_fmt_setup);
static int valid_policy = 1;
static ssize_t ima_show_htable_value(char __user *buf, size_t count,
loff_t *ppos, atomic_long_t *val)
{
char tmpbuf[32]; /* greater than largest 'long' string value */
ssize_t len;
len = scnprintf(tmpbuf, sizeof(tmpbuf), "%li\n", atomic_long_read(val));
return simple_read_from_buffer(buf, count, ppos, tmpbuf, len);
}
static ssize_t ima_show_htable_violations(struct file *filp,
char __user *buf,
size_t count, loff_t *ppos)
{
return ima_show_htable_value(buf, count, ppos, &ima_htable.violations);
}
static const struct file_operations ima_htable_violations_ops = {
.read = ima_show_htable_violations,
.llseek = generic_file_llseek,
};
static ssize_t ima_show_measurements_count(struct file *filp,
char __user *buf,
size_t count, loff_t *ppos)
{
return ima_show_htable_value(buf, count, ppos, &ima_htable.len);
}
static const struct file_operations ima_measurements_count_ops = {
.read = ima_show_measurements_count,
.llseek = generic_file_llseek,
};
/* returns pointer to hlist_node */
static void *ima_measurements_start(struct seq_file *m, loff_t *pos)
{
loff_t l = *pos;
struct ima_queue_entry *qe;
/* we need a lock since pos could point beyond last element */
rcu_read_lock();
list_for_each_entry_rcu(qe, &ima_measurements, later) {
if (!l--) {
rcu_read_unlock();
return qe;
}
}
rcu_read_unlock();
return NULL;
}
static void *ima_measurements_next(struct seq_file *m, void *v, loff_t *pos)
{
struct ima_queue_entry *qe = v;
/* lock protects when reading beyond last element
* against concurrent list-extension
*/
rcu_read_lock();
qe = list_entry_rcu(qe->later.next, struct ima_queue_entry, later);
rcu_read_unlock();
(*pos)++;
return (&qe->later == &ima_measurements) ? NULL : qe;
}
static void ima_measurements_stop(struct seq_file *m, void *v)
{
}
void ima_putc(struct seq_file *m, void *data, int datalen)
{
while (datalen--)
seq_putc(m, *(char *)data++);
}
static struct dentry **ascii_securityfs_measurement_lists __ro_after_init;
static struct dentry **binary_securityfs_measurement_lists __ro_after_init;
static int securityfs_measurement_list_count __ro_after_init;
static void lookup_template_data_hash_algo(int *algo_idx, enum hash_algo *algo,
struct seq_file *m,
struct dentry **lists)
{
struct dentry *dentry;
int i;
dentry = file_dentry(m->file);
for (i = 0; i < securityfs_measurement_list_count; i++) {
if (dentry == lists[i]) {
*algo_idx = i;
*algo = ima_algo_array[i].algo;
break;
}
}
}
/* print format:
* 32bit-le=pcr#
* char[n]=template digest
* 32bit-le=template name size
* char[n]=template name
* [eventdata length]
* eventdata[n]=template specific data
*/
int ima_measurements_show(struct seq_file *m, void *v)
{
/* the list never shrinks, so we don't need a lock here */
struct ima_queue_entry *qe = v;
struct ima_template_entry *e;
char *template_name;
u32 pcr, namelen, template_data_len; /* temporary fields */
bool is_ima_template = false;
enum hash_algo algo;
int i, algo_idx;
algo_idx = ima_sha1_idx;
algo = HASH_ALGO_SHA1;
if (m->file != NULL)
lookup_template_data_hash_algo(&algo_idx, &algo, m,
binary_securityfs_measurement_lists);
/* get entry */
e = qe->entry;
if (e == NULL)
return -1;
template_name = (e->template_desc->name[0] != '\0') ?
e->template_desc->name : e->template_desc->fmt;
/*
* 1st: PCRIndex
* PCR used defaults to the same (config option) in
* little-endian format, unless set in policy
*/
pcr = !ima_canonical_fmt ? e->pcr : (__force u32)cpu_to_le32(e->pcr);
ima_putc(m, &pcr, sizeof(e->pcr));
/* 2nd: template digest */
ima_putc(m, e->digests[algo_idx].digest, hash_digest_size[algo]);
/* 3rd: template name size */
namelen = !ima_canonical_fmt ? strlen(template_name) :
(__force u32)cpu_to_le32(strlen(template_name));
ima_putc(m, &namelen, sizeof(namelen));
/* 4th: template name */
ima_putc(m, template_name, strlen(template_name));
/* 5th: template length (except for 'ima' template) */
if (strcmp(template_name, IMA_TEMPLATE_IMA_NAME) == 0)
is_ima_template = true;
if (!is_ima_template) {
template_data_len = !ima_canonical_fmt ? e->template_data_len :
(__force u32)cpu_to_le32(e->template_data_len);
ima_putc(m, &template_data_len, sizeof(e->template_data_len));
}
/* 6th: template specific data */
for (i = 0; i < e->template_desc->num_fields; i++) {
enum ima_show_type show = IMA_SHOW_BINARY;
const struct ima_template_field *field =
e->template_desc->fields[i];
if (is_ima_template && strcmp(field->field_id, "d") == 0)
show = IMA_SHOW_BINARY_NO_FIELD_LEN;
if (is_ima_template && strcmp(field->field_id, "n") == 0)
show = IMA_SHOW_BINARY_OLD_STRING_FMT;
field->field_show(m, show, &e->template_data[i]);
}
return 0;
}
static const struct seq_operations ima_measurments_seqops = {
.start = ima_measurements_start,
.next = ima_measurements_next,
.stop = ima_measurements_stop,
.show = ima_measurements_show
};
static int ima_measurements_open(struct inode *inode, struct file *file)
{
return seq_open(file, &ima_measurments_seqops);
}
static const struct file_operations ima_measurements_ops = {
.open = ima_measurements_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release,
};
void ima_print_digest(struct seq_file *m, u8 *digest, u32 size)
{
u32 i;
for (i = 0; i < size; i++)
seq_printf(m, "%02x", *(digest + i));
}
/* print in ascii */
static int ima_ascii_measurements_show(struct seq_file *m, void *v)
{
/* the list never shrinks, so we don't need a lock here */
struct ima_queue_entry *qe = v;
struct ima_template_entry *e;
char *template_name;
enum hash_algo algo;
int i, algo_idx;
algo_idx = ima_sha1_idx;
algo = HASH_ALGO_SHA1;
if (m->file != NULL)
lookup_template_data_hash_algo(&algo_idx, &algo, m,
ascii_securityfs_measurement_lists);
/* get entry */
e = qe->entry;
if (e == NULL)
return -1;
template_name = (e->template_desc->name[0] != '\0') ?
e->template_desc->name : e->template_desc->fmt;
/* 1st: PCR used (config option) */
seq_printf(m, "%2d ", e->pcr);
/* 2nd: template hash */
ima_print_digest(m, e->digests[algo_idx].digest, hash_digest_size[algo]);
/* 3th: template name */
seq_printf(m, " %s", template_name);
/* 4th: template specific data */
for (i = 0; i < e->template_desc->num_fields; i++) {
seq_puts(m, " ");
if (e->template_data[i].len == 0)
continue;
e->template_desc->fields[i]->field_show(m, IMA_SHOW_ASCII,
&e->template_data[i]);
}
seq_puts(m, "\n");
return 0;
}
static const struct seq_operations ima_ascii_measurements_seqops = {
.start = ima_measurements_start,
.next = ima_measurements_next,
.stop = ima_measurements_stop,
.show = ima_ascii_measurements_show
};
static int ima_ascii_measurements_open(struct inode *inode, struct file *file)
{
return seq_open(file, &ima_ascii_measurements_seqops);
}
static const struct file_operations ima_ascii_measurements_ops = {
.open = ima_ascii_measurements_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release,
};
static ssize_t ima_read_policy(char *path)
{
void *data = NULL;
char *datap;
size_t size;
int rc, pathlen = strlen(path);
char *p;
/* remove \n */
datap = path;
strsep(&datap, "\n");
rc = kernel_read_file_from_path(path, 0, &data, INT_MAX, NULL,
READING_POLICY);
if (rc < 0) {
pr_err("Unable to open file: %s (%d)", path, rc);
return rc;
}
size = rc;
rc = 0;
datap = data;
while (size > 0 && (p = strsep(&datap, "\n"))) {
pr_debug("rule: %s\n", p);
rc = ima_parse_add_rule(p);
if (rc < 0)
break;
size -= rc;
}
vfree(data);
if (rc < 0)
return rc;
else if (size)
return -EINVAL;
else
return pathlen;
}
static ssize_t ima_write_policy(struct file *file, const char __user *buf,
size_t datalen, loff_t *ppos)
{
char *data;
ssize_t result;
if (datalen >= PAGE_SIZE)
datalen = PAGE_SIZE - 1;
/* No partial writes. */
result = -EINVAL;
if (*ppos != 0)
goto out;
data = memdup_user_nul(buf, datalen);
if (IS_ERR(data)) {
result = PTR_ERR(data);
goto out;
}
result = mutex_lock_interruptible(&ima_write_mutex);
if (result < 0)
goto out_free;
if (data[0] == '/') {
result = ima_read_policy(data);
} else if (ima_appraise & IMA_APPRAISE_POLICY) {
pr_err("signed policy file (specified as an absolute pathname) required\n");
integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL, NULL,
"policy_update", "signed policy required",
1, 0);
result = -EACCES;
} else {
result = ima_parse_add_rule(data);
}
mutex_unlock(&ima_write_mutex);
out_free:
kfree(data);
out:
if (result < 0)
valid_policy = 0;
return result;
}
static struct dentry *ima_dir;
static struct dentry *ima_symlink;
static struct dentry *binary_runtime_measurements;
static struct dentry *ascii_runtime_measurements;
static struct dentry *runtime_measurements_count;
static struct dentry *violations;
static struct dentry *ima_policy;
enum ima_fs_flags {
IMA_FS_BUSY,
};
static unsigned long ima_fs_flags;
#ifdef CONFIG_IMA_READ_POLICY
static const struct seq_operations ima_policy_seqops = {
.start = ima_policy_start,
.next = ima_policy_next,
.stop = ima_policy_stop,
.show = ima_policy_show,
};
#endif
static void __init remove_securityfs_measurement_lists(struct dentry **lists)
{
int i;
if (lists) {
for (i = 0; i < securityfs_measurement_list_count; i++)
securityfs_remove(lists[i]);
kfree(lists);
}
}
static int __init create_securityfs_measurement_lists(void)
{
char file_name[NAME_MAX + 1];
struct dentry *dentry;
u16 algo;
int i;
securityfs_measurement_list_count = NR_BANKS(ima_tpm_chip);
if (ima_sha1_idx >= NR_BANKS(ima_tpm_chip))
securityfs_measurement_list_count++;
ascii_securityfs_measurement_lists =
kcalloc(securityfs_measurement_list_count, sizeof(struct dentry *),
GFP_KERNEL);
if (!ascii_securityfs_measurement_lists)
return -ENOMEM;
binary_securityfs_measurement_lists =
kcalloc(securityfs_measurement_list_count, sizeof(struct dentry *),
GFP_KERNEL);
if (!binary_securityfs_measurement_lists)
return -ENOMEM;
for (i = 0; i < securityfs_measurement_list_count; i++) {
algo = ima_algo_array[i].algo;
sprintf(file_name, "ascii_runtime_measurements_%s",
hash_algo_name[algo]);
dentry = securityfs_create_file(file_name, S_IRUSR | S_IRGRP,
ima_dir, NULL,
&ima_ascii_measurements_ops);
if (IS_ERR(dentry))
return PTR_ERR(dentry);
ascii_securityfs_measurement_lists[i] = dentry;
sprintf(file_name, "binary_runtime_measurements_%s",
hash_algo_name[algo]);
dentry = securityfs_create_file(file_name, S_IRUSR | S_IRGRP,
ima_dir, NULL,
&ima_measurements_ops);
if (IS_ERR(dentry))
return PTR_ERR(dentry);
binary_securityfs_measurement_lists[i] = dentry;
}
return 0;
}
/*
* ima_open_policy: sequentialize access to the policy file
*/
static int ima_open_policy(struct inode *inode, struct file *filp)
{
if (!(filp->f_flags & O_WRONLY)) {
#ifndef CONFIG_IMA_READ_POLICY
return -EACCES;
#else
if ((filp->f_flags & O_ACCMODE) != O_RDONLY)
return -EACCES;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
return seq_open(filp, &ima_policy_seqops);
#endif
}
if (test_and_set_bit(IMA_FS_BUSY, &ima_fs_flags))
return -EBUSY;
return 0;
}
/*
* ima_release_policy - start using the new measure policy rules.
*
* Initially, ima_measure points to the default policy rules, now
* point to the new policy rules, and remove the securityfs policy file,
* assuming a valid policy.
*/
static int ima_release_policy(struct inode *inode, struct file *file)
{
const char *cause = valid_policy ? "completed" : "failed";
if ((file->f_flags & O_ACCMODE) == O_RDONLY)
return seq_release(inode, file);
if (valid_policy && ima_check_policy() < 0) {
cause = "failed";
valid_policy = 0;
}
pr_info("policy update %s\n", cause);
integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL, NULL,
"policy_update", cause, !valid_policy, 0);
if (!valid_policy) {
ima_delete_rules();
valid_policy = 1;
clear_bit(IMA_FS_BUSY, &ima_fs_flags);
return 0;
}
ima_update_policy();
#if !defined(CONFIG_IMA_WRITE_POLICY) && !defined(CONFIG_IMA_READ_POLICY)
securityfs_remove(ima_policy);
ima_policy = NULL;
#elif defined(CONFIG_IMA_WRITE_POLICY)
clear_bit(IMA_FS_BUSY, &ima_fs_flags);
#elif defined(CONFIG_IMA_READ_POLICY)
inode->i_mode &= ~S_IWUSR;
#endif
return 0;
}
static const struct file_operations ima_measure_policy_ops = {
.open = ima_open_policy,
.write = ima_write_policy,
.read = seq_read,
.release = ima_release_policy,
.llseek = generic_file_llseek,
};
int __init ima_fs_init(void)
{
int ret;
ascii_securityfs_measurement_lists = NULL;
binary_securityfs_measurement_lists = NULL;
ima_dir = securityfs_create_dir("ima", integrity_dir);
if (IS_ERR(ima_dir))
return PTR_ERR(ima_dir);
ima_symlink = securityfs_create_symlink("ima", NULL, "integrity/ima",
NULL);
if (IS_ERR(ima_symlink)) {
ret = PTR_ERR(ima_symlink);
goto out;
}
ret = create_securityfs_measurement_lists();
if (ret != 0)
goto out;
binary_runtime_measurements =
securityfs_create_symlink("binary_runtime_measurements", ima_dir,
"binary_runtime_measurements_sha1", NULL);
if (IS_ERR(binary_runtime_measurements)) {
ret = PTR_ERR(binary_runtime_measurements);
goto out;
}
ascii_runtime_measurements =
securityfs_create_symlink("ascii_runtime_measurements", ima_dir,
"ascii_runtime_measurements_sha1", NULL);
if (IS_ERR(ascii_runtime_measurements)) {
ret = PTR_ERR(ascii_runtime_measurements);
goto out;
}
runtime_measurements_count =
securityfs_create_file("runtime_measurements_count",
S_IRUSR | S_IRGRP, ima_dir, NULL,
&ima_measurements_count_ops);
if (IS_ERR(runtime_measurements_count)) {
ret = PTR_ERR(runtime_measurements_count);
goto out;
}
violations =
securityfs_create_file("violations", S_IRUSR | S_IRGRP,
ima_dir, NULL, &ima_htable_violations_ops);
if (IS_ERR(violations)) {
ret = PTR_ERR(violations);
goto out;
}
ima_policy = securityfs_create_file("policy", POLICY_FILE_FLAGS,
ima_dir, NULL,
&ima_measure_policy_ops);
if (IS_ERR(ima_policy)) {
ret = PTR_ERR(ima_policy);
goto out;
}
return 0;
out:
securityfs_remove(ima_policy);
securityfs_remove(violations);
securityfs_remove(runtime_measurements_count);
securityfs_remove(ascii_runtime_measurements);
securityfs_remove(binary_runtime_measurements);
remove_securityfs_measurement_lists(ascii_securityfs_measurement_lists);
remove_securityfs_measurement_lists(binary_securityfs_measurement_lists);
securityfs_measurement_list_count = 0;
securityfs_remove(ima_symlink);
securityfs_remove(ima_dir);
return ret;
}
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