726 lines
20 KiB
C
726 lines
20 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
|
|
/*
|
|
* Integrity Measurement Architecture
|
|
*
|
|
* Copyright (C) 2005,2006,2007,2008 IBM Corporation
|
|
*
|
|
* Authors:
|
|
* Reiner Sailer <sailer@watson.ibm.com>
|
|
* Serge Hallyn <serue@us.ibm.com>
|
|
* Kylene Hall <kylene@us.ibm.com>
|
|
* Mimi Zohar <zohar@us.ibm.com>
|
|
*
|
|
* File: ima_main.c
|
|
* implements the IMA hooks: ima_bprm_check, ima_file_mmap,
|
|
* and ima_file_check.
|
|
*/
|
|
|
|
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
|
|
|
|
#include <linux/module.h>
|
|
#include <linux/file.h>
|
|
#include <linux/binfmts.h>
|
|
#include <linux/mount.h>
|
|
#include <linux/mman.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/xattr.h>
|
|
#include <linux/ima.h>
|
|
#include <linux/iversion.h>
|
|
#include <linux/fs.h>
|
|
|
|
#include "ima.h"
|
|
|
|
#ifdef CONFIG_IMA_APPRAISE
|
|
int ima_appraise = IMA_APPRAISE_ENFORCE;
|
|
#else
|
|
int ima_appraise;
|
|
#endif
|
|
|
|
int ima_hash_algo = HASH_ALGO_SHA1;
|
|
static int hash_setup_done;
|
|
|
|
static struct notifier_block ima_lsm_policy_notifier = {
|
|
.notifier_call = ima_lsm_policy_change,
|
|
};
|
|
|
|
static int __init hash_setup(char *str)
|
|
{
|
|
struct ima_template_desc *template_desc = ima_template_desc_current();
|
|
int i;
|
|
|
|
if (hash_setup_done)
|
|
return 1;
|
|
|
|
if (strcmp(template_desc->name, IMA_TEMPLATE_IMA_NAME) == 0) {
|
|
if (strncmp(str, "sha1", 4) == 0)
|
|
ima_hash_algo = HASH_ALGO_SHA1;
|
|
else if (strncmp(str, "md5", 3) == 0)
|
|
ima_hash_algo = HASH_ALGO_MD5;
|
|
else
|
|
return 1;
|
|
goto out;
|
|
}
|
|
|
|
i = match_string(hash_algo_name, HASH_ALGO__LAST, str);
|
|
if (i < 0)
|
|
return 1;
|
|
|
|
ima_hash_algo = i;
|
|
out:
|
|
hash_setup_done = 1;
|
|
return 1;
|
|
}
|
|
__setup("ima_hash=", hash_setup);
|
|
|
|
/* Prevent mmap'ing a file execute that is already mmap'ed write */
|
|
static int mmap_violation_check(enum ima_hooks func, struct file *file,
|
|
char **pathbuf, const char **pathname,
|
|
char *filename)
|
|
{
|
|
struct inode *inode;
|
|
int rc = 0;
|
|
|
|
if ((func == MMAP_CHECK) && mapping_writably_mapped(file->f_mapping)) {
|
|
rc = -ETXTBSY;
|
|
inode = file_inode(file);
|
|
|
|
if (!*pathbuf) /* ima_rdwr_violation possibly pre-fetched */
|
|
*pathname = ima_d_path(&file->f_path, pathbuf,
|
|
filename);
|
|
integrity_audit_msg(AUDIT_INTEGRITY_DATA, inode, *pathname,
|
|
"mmap_file", "mmapped_writers", rc, 0);
|
|
}
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
* ima_rdwr_violation_check
|
|
*
|
|
* Only invalidate the PCR for measured files:
|
|
* - Opening a file for write when already open for read,
|
|
* results in a time of measure, time of use (ToMToU) error.
|
|
* - Opening a file for read when already open for write,
|
|
* could result in a file measurement error.
|
|
*
|
|
*/
|
|
static void ima_rdwr_violation_check(struct file *file,
|
|
struct integrity_iint_cache *iint,
|
|
int must_measure,
|
|
char **pathbuf,
|
|
const char **pathname,
|
|
char *filename)
|
|
{
|
|
struct inode *inode = file_inode(file);
|
|
fmode_t mode = file->f_mode;
|
|
bool send_tomtou = false, send_writers = false;
|
|
|
|
if (mode & FMODE_WRITE) {
|
|
if (atomic_read(&inode->i_readcount) && IS_IMA(inode)) {
|
|
if (!iint)
|
|
iint = integrity_iint_find(inode);
|
|
/* IMA_MEASURE is set from reader side */
|
|
if (iint && test_bit(IMA_MUST_MEASURE,
|
|
&iint->atomic_flags))
|
|
send_tomtou = true;
|
|
}
|
|
} else {
|
|
if (must_measure)
|
|
set_bit(IMA_MUST_MEASURE, &iint->atomic_flags);
|
|
if (inode_is_open_for_write(inode) && must_measure)
|
|
send_writers = true;
|
|
}
|
|
|
|
if (!send_tomtou && !send_writers)
|
|
return;
|
|
|
|
*pathname = ima_d_path(&file->f_path, pathbuf, filename);
|
|
|
|
if (send_tomtou)
|
|
ima_add_violation(file, *pathname, iint,
|
|
"invalid_pcr", "ToMToU");
|
|
if (send_writers)
|
|
ima_add_violation(file, *pathname, iint,
|
|
"invalid_pcr", "open_writers");
|
|
}
|
|
|
|
static void ima_check_last_writer(struct integrity_iint_cache *iint,
|
|
struct inode *inode, struct file *file)
|
|
{
|
|
fmode_t mode = file->f_mode;
|
|
bool update;
|
|
|
|
if (!(mode & FMODE_WRITE))
|
|
return;
|
|
|
|
mutex_lock(&iint->mutex);
|
|
if (atomic_read(&inode->i_writecount) == 1) {
|
|
update = test_and_clear_bit(IMA_UPDATE_XATTR,
|
|
&iint->atomic_flags);
|
|
if (!IS_I_VERSION(inode) ||
|
|
!inode_eq_iversion(inode, iint->version) ||
|
|
(iint->flags & IMA_NEW_FILE)) {
|
|
iint->flags &= ~(IMA_DONE_MASK | IMA_NEW_FILE);
|
|
iint->measured_pcrs = 0;
|
|
if (update)
|
|
ima_update_xattr(iint, file);
|
|
}
|
|
}
|
|
mutex_unlock(&iint->mutex);
|
|
}
|
|
|
|
/**
|
|
* ima_file_free - called on __fput()
|
|
* @file: pointer to file structure being freed
|
|
*
|
|
* Flag files that changed, based on i_version
|
|
*/
|
|
void ima_file_free(struct file *file)
|
|
{
|
|
struct inode *inode = file_inode(file);
|
|
struct integrity_iint_cache *iint;
|
|
|
|
if (!ima_policy_flag || !S_ISREG(inode->i_mode))
|
|
return;
|
|
|
|
iint = integrity_iint_find(inode);
|
|
if (!iint)
|
|
return;
|
|
|
|
ima_check_last_writer(iint, inode, file);
|
|
}
|
|
|
|
static int process_measurement(struct file *file, const struct cred *cred,
|
|
u32 secid, char *buf, loff_t size, int mask,
|
|
enum ima_hooks func)
|
|
{
|
|
struct inode *inode = file_inode(file);
|
|
struct integrity_iint_cache *iint = NULL;
|
|
struct ima_template_desc *template_desc = NULL;
|
|
char *pathbuf = NULL;
|
|
char filename[NAME_MAX];
|
|
const char *pathname = NULL;
|
|
int rc = 0, action, must_appraise = 0;
|
|
int pcr = CONFIG_IMA_MEASURE_PCR_IDX;
|
|
struct evm_ima_xattr_data *xattr_value = NULL;
|
|
struct modsig *modsig = NULL;
|
|
int xattr_len = 0;
|
|
bool violation_check;
|
|
enum hash_algo hash_algo;
|
|
|
|
if (!ima_policy_flag || !S_ISREG(inode->i_mode))
|
|
return 0;
|
|
|
|
/* Return an IMA_MEASURE, IMA_APPRAISE, IMA_AUDIT action
|
|
* bitmask based on the appraise/audit/measurement policy.
|
|
* Included is the appraise submask.
|
|
*/
|
|
action = ima_get_action(inode, cred, secid, mask, func, &pcr,
|
|
&template_desc);
|
|
violation_check = ((func == FILE_CHECK || func == MMAP_CHECK) &&
|
|
(ima_policy_flag & IMA_MEASURE));
|
|
if (!action && !violation_check)
|
|
return 0;
|
|
|
|
must_appraise = action & IMA_APPRAISE;
|
|
|
|
/* Is the appraise rule hook specific? */
|
|
if (action & IMA_FILE_APPRAISE)
|
|
func = FILE_CHECK;
|
|
|
|
inode_lock(inode);
|
|
|
|
if (action) {
|
|
iint = integrity_inode_get(inode);
|
|
if (!iint)
|
|
rc = -ENOMEM;
|
|
}
|
|
|
|
if (!rc && violation_check)
|
|
ima_rdwr_violation_check(file, iint, action & IMA_MEASURE,
|
|
&pathbuf, &pathname, filename);
|
|
|
|
inode_unlock(inode);
|
|
|
|
if (rc)
|
|
goto out;
|
|
if (!action)
|
|
goto out;
|
|
|
|
mutex_lock(&iint->mutex);
|
|
|
|
if (test_and_clear_bit(IMA_CHANGE_ATTR, &iint->atomic_flags))
|
|
/* reset appraisal flags if ima_inode_post_setattr was called */
|
|
iint->flags &= ~(IMA_APPRAISE | IMA_APPRAISED |
|
|
IMA_APPRAISE_SUBMASK | IMA_APPRAISED_SUBMASK |
|
|
IMA_ACTION_FLAGS);
|
|
|
|
/*
|
|
* Re-evaulate the file if either the xattr has changed or the
|
|
* kernel has no way of detecting file change on the filesystem.
|
|
* (Limited to privileged mounted filesystems.)
|
|
*/
|
|
if (test_and_clear_bit(IMA_CHANGE_XATTR, &iint->atomic_flags) ||
|
|
((inode->i_sb->s_iflags & SB_I_IMA_UNVERIFIABLE_SIGNATURE) &&
|
|
!(inode->i_sb->s_iflags & SB_I_UNTRUSTED_MOUNTER) &&
|
|
!(action & IMA_FAIL_UNVERIFIABLE_SIGS))) {
|
|
iint->flags &= ~IMA_DONE_MASK;
|
|
iint->measured_pcrs = 0;
|
|
}
|
|
|
|
/* Determine if already appraised/measured based on bitmask
|
|
* (IMA_MEASURE, IMA_MEASURED, IMA_XXXX_APPRAISE, IMA_XXXX_APPRAISED,
|
|
* IMA_AUDIT, IMA_AUDITED)
|
|
*/
|
|
iint->flags |= action;
|
|
action &= IMA_DO_MASK;
|
|
action &= ~((iint->flags & (IMA_DONE_MASK ^ IMA_MEASURED)) >> 1);
|
|
|
|
/* If target pcr is already measured, unset IMA_MEASURE action */
|
|
if ((action & IMA_MEASURE) && (iint->measured_pcrs & (0x1 << pcr)))
|
|
action ^= IMA_MEASURE;
|
|
|
|
/* HASH sets the digital signature and update flags, nothing else */
|
|
if ((action & IMA_HASH) &&
|
|
!(test_bit(IMA_DIGSIG, &iint->atomic_flags))) {
|
|
xattr_len = ima_read_xattr(file_dentry(file), &xattr_value);
|
|
if ((xattr_value && xattr_len > 2) &&
|
|
(xattr_value->type == EVM_IMA_XATTR_DIGSIG))
|
|
set_bit(IMA_DIGSIG, &iint->atomic_flags);
|
|
iint->flags |= IMA_HASHED;
|
|
action ^= IMA_HASH;
|
|
set_bit(IMA_UPDATE_XATTR, &iint->atomic_flags);
|
|
}
|
|
|
|
/* Nothing to do, just return existing appraised status */
|
|
if (!action) {
|
|
if (must_appraise) {
|
|
rc = mmap_violation_check(func, file, &pathbuf,
|
|
&pathname, filename);
|
|
if (!rc)
|
|
rc = ima_get_cache_status(iint, func);
|
|
}
|
|
goto out_locked;
|
|
}
|
|
|
|
if ((action & IMA_APPRAISE_SUBMASK) ||
|
|
strcmp(template_desc->name, IMA_TEMPLATE_IMA_NAME) != 0) {
|
|
/* read 'security.ima' */
|
|
xattr_len = ima_read_xattr(file_dentry(file), &xattr_value);
|
|
|
|
/*
|
|
* Read the appended modsig if allowed by the policy, and allow
|
|
* an additional measurement list entry, if needed, based on the
|
|
* template format and whether the file was already measured.
|
|
*/
|
|
if (iint->flags & IMA_MODSIG_ALLOWED) {
|
|
rc = ima_read_modsig(func, buf, size, &modsig);
|
|
|
|
if (!rc && ima_template_has_modsig(template_desc) &&
|
|
iint->flags & IMA_MEASURED)
|
|
action |= IMA_MEASURE;
|
|
}
|
|
}
|
|
|
|
hash_algo = ima_get_hash_algo(xattr_value, xattr_len);
|
|
|
|
rc = ima_collect_measurement(iint, file, buf, size, hash_algo, modsig);
|
|
if (rc != 0 && rc != -EBADF && rc != -EINVAL)
|
|
goto out_locked;
|
|
|
|
if (!pathbuf) /* ima_rdwr_violation possibly pre-fetched */
|
|
pathname = ima_d_path(&file->f_path, &pathbuf, filename);
|
|
|
|
if (action & IMA_MEASURE)
|
|
ima_store_measurement(iint, file, pathname,
|
|
xattr_value, xattr_len, modsig, pcr,
|
|
template_desc);
|
|
if (rc == 0 && (action & IMA_APPRAISE_SUBMASK)) {
|
|
inode_lock(inode);
|
|
rc = ima_appraise_measurement(func, iint, file, pathname,
|
|
xattr_value, xattr_len, modsig);
|
|
inode_unlock(inode);
|
|
if (!rc)
|
|
rc = mmap_violation_check(func, file, &pathbuf,
|
|
&pathname, filename);
|
|
}
|
|
if (action & IMA_AUDIT)
|
|
ima_audit_measurement(iint, pathname);
|
|
|
|
if ((file->f_flags & O_DIRECT) && (iint->flags & IMA_PERMIT_DIRECTIO))
|
|
rc = 0;
|
|
out_locked:
|
|
if ((mask & MAY_WRITE) && test_bit(IMA_DIGSIG, &iint->atomic_flags) &&
|
|
!(iint->flags & IMA_NEW_FILE))
|
|
rc = -EACCES;
|
|
mutex_unlock(&iint->mutex);
|
|
kfree(xattr_value);
|
|
ima_free_modsig(modsig);
|
|
out:
|
|
if (pathbuf)
|
|
__putname(pathbuf);
|
|
if (must_appraise) {
|
|
if (rc && (ima_appraise & IMA_APPRAISE_ENFORCE))
|
|
return -EACCES;
|
|
if (file->f_mode & FMODE_WRITE)
|
|
set_bit(IMA_UPDATE_XATTR, &iint->atomic_flags);
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* ima_file_mmap - based on policy, collect/store measurement.
|
|
* @file: pointer to the file to be measured (May be NULL)
|
|
* @prot: contains the protection that will be applied by the kernel.
|
|
*
|
|
* Measure files being mmapped executable based on the ima_must_measure()
|
|
* policy decision.
|
|
*
|
|
* On success return 0. On integrity appraisal error, assuming the file
|
|
* is in policy and IMA-appraisal is in enforcing mode, return -EACCES.
|
|
*/
|
|
int ima_file_mmap(struct file *file, unsigned long prot)
|
|
{
|
|
u32 secid;
|
|
|
|
if (file && (prot & PROT_EXEC)) {
|
|
security_task_getsecid(current, &secid);
|
|
return process_measurement(file, current_cred(), secid, NULL,
|
|
0, MAY_EXEC, MMAP_CHECK);
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* ima_bprm_check - based on policy, collect/store measurement.
|
|
* @bprm: contains the linux_binprm structure
|
|
*
|
|
* The OS protects against an executable file, already open for write,
|
|
* from being executed in deny_write_access() and an executable file,
|
|
* already open for execute, from being modified in get_write_access().
|
|
* So we can be certain that what we verify and measure here is actually
|
|
* what is being executed.
|
|
*
|
|
* On success return 0. On integrity appraisal error, assuming the file
|
|
* is in policy and IMA-appraisal is in enforcing mode, return -EACCES.
|
|
*/
|
|
int ima_bprm_check(struct linux_binprm *bprm)
|
|
{
|
|
int ret;
|
|
u32 secid;
|
|
|
|
security_task_getsecid(current, &secid);
|
|
ret = process_measurement(bprm->file, current_cred(), secid, NULL, 0,
|
|
MAY_EXEC, BPRM_CHECK);
|
|
if (ret)
|
|
return ret;
|
|
|
|
security_cred_getsecid(bprm->cred, &secid);
|
|
return process_measurement(bprm->file, bprm->cred, secid, NULL, 0,
|
|
MAY_EXEC, CREDS_CHECK);
|
|
}
|
|
|
|
/**
|
|
* ima_path_check - based on policy, collect/store measurement.
|
|
* @file: pointer to the file to be measured
|
|
* @mask: contains MAY_READ, MAY_WRITE, MAY_EXEC or MAY_APPEND
|
|
*
|
|
* Measure files based on the ima_must_measure() policy decision.
|
|
*
|
|
* On success return 0. On integrity appraisal error, assuming the file
|
|
* is in policy and IMA-appraisal is in enforcing mode, return -EACCES.
|
|
*/
|
|
int ima_file_check(struct file *file, int mask)
|
|
{
|
|
u32 secid;
|
|
|
|
security_task_getsecid(current, &secid);
|
|
return process_measurement(file, current_cred(), secid, NULL, 0,
|
|
mask & (MAY_READ | MAY_WRITE | MAY_EXEC |
|
|
MAY_APPEND), FILE_CHECK);
|
|
}
|
|
EXPORT_SYMBOL_GPL(ima_file_check);
|
|
|
|
/**
|
|
* ima_post_create_tmpfile - mark newly created tmpfile as new
|
|
* @file : newly created tmpfile
|
|
*
|
|
* No measuring, appraising or auditing of newly created tmpfiles is needed.
|
|
* Skip calling process_measurement(), but indicate which newly, created
|
|
* tmpfiles are in policy.
|
|
*/
|
|
void ima_post_create_tmpfile(struct inode *inode)
|
|
{
|
|
struct integrity_iint_cache *iint;
|
|
int must_appraise;
|
|
|
|
must_appraise = ima_must_appraise(inode, MAY_ACCESS, FILE_CHECK);
|
|
if (!must_appraise)
|
|
return;
|
|
|
|
/* Nothing to do if we can't allocate memory */
|
|
iint = integrity_inode_get(inode);
|
|
if (!iint)
|
|
return;
|
|
|
|
/* needed for writing the security xattrs */
|
|
set_bit(IMA_UPDATE_XATTR, &iint->atomic_flags);
|
|
iint->ima_file_status = INTEGRITY_PASS;
|
|
}
|
|
|
|
/**
|
|
* ima_post_path_mknod - mark as a new inode
|
|
* @dentry: newly created dentry
|
|
*
|
|
* Mark files created via the mknodat syscall as new, so that the
|
|
* file data can be written later.
|
|
*/
|
|
void ima_post_path_mknod(struct dentry *dentry)
|
|
{
|
|
struct integrity_iint_cache *iint;
|
|
struct inode *inode = dentry->d_inode;
|
|
int must_appraise;
|
|
|
|
must_appraise = ima_must_appraise(inode, MAY_ACCESS, FILE_CHECK);
|
|
if (!must_appraise)
|
|
return;
|
|
|
|
/* Nothing to do if we can't allocate memory */
|
|
iint = integrity_inode_get(inode);
|
|
if (!iint)
|
|
return;
|
|
|
|
/* needed for re-opening empty files */
|
|
iint->flags |= IMA_NEW_FILE;
|
|
}
|
|
|
|
/**
|
|
* ima_read_file - pre-measure/appraise hook decision based on policy
|
|
* @file: pointer to the file to be measured/appraised/audit
|
|
* @read_id: caller identifier
|
|
*
|
|
* Permit reading a file based on policy. The policy rules are written
|
|
* in terms of the policy identifier. Appraising the integrity of
|
|
* a file requires a file descriptor.
|
|
*
|
|
* For permission return 0, otherwise return -EACCES.
|
|
*/
|
|
int ima_read_file(struct file *file, enum kernel_read_file_id read_id)
|
|
{
|
|
/*
|
|
* READING_FIRMWARE_PREALLOC_BUFFER
|
|
*
|
|
* Do devices using pre-allocated memory run the risk of the
|
|
* firmware being accessible to the device prior to the completion
|
|
* of IMA's signature verification any more than when using two
|
|
* buffers?
|
|
*/
|
|
return 0;
|
|
}
|
|
|
|
const int read_idmap[READING_MAX_ID] = {
|
|
[READING_FIRMWARE] = FIRMWARE_CHECK,
|
|
[READING_FIRMWARE_PREALLOC_BUFFER] = FIRMWARE_CHECK,
|
|
[READING_MODULE] = MODULE_CHECK,
|
|
[READING_KEXEC_IMAGE] = KEXEC_KERNEL_CHECK,
|
|
[READING_KEXEC_INITRAMFS] = KEXEC_INITRAMFS_CHECK,
|
|
[READING_POLICY] = POLICY_CHECK
|
|
};
|
|
|
|
/**
|
|
* ima_post_read_file - in memory collect/appraise/audit measurement
|
|
* @file: pointer to the file to be measured/appraised/audit
|
|
* @buf: pointer to in memory file contents
|
|
* @size: size of in memory file contents
|
|
* @read_id: caller identifier
|
|
*
|
|
* Measure/appraise/audit in memory file based on policy. Policy rules
|
|
* are written in terms of a policy identifier.
|
|
*
|
|
* On success return 0. On integrity appraisal error, assuming the file
|
|
* is in policy and IMA-appraisal is in enforcing mode, return -EACCES.
|
|
*/
|
|
int ima_post_read_file(struct file *file, void *buf, loff_t size,
|
|
enum kernel_read_file_id read_id)
|
|
{
|
|
enum ima_hooks func;
|
|
u32 secid;
|
|
|
|
if (!file && read_id == READING_FIRMWARE) {
|
|
if ((ima_appraise & IMA_APPRAISE_FIRMWARE) &&
|
|
(ima_appraise & IMA_APPRAISE_ENFORCE)) {
|
|
pr_err("Prevent firmware loading_store.\n");
|
|
return -EACCES; /* INTEGRITY_UNKNOWN */
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/* permit signed certs */
|
|
if (!file && read_id == READING_X509_CERTIFICATE)
|
|
return 0;
|
|
|
|
if (!file || !buf || size == 0) { /* should never happen */
|
|
if (ima_appraise & IMA_APPRAISE_ENFORCE)
|
|
return -EACCES;
|
|
return 0;
|
|
}
|
|
|
|
func = read_idmap[read_id] ?: FILE_CHECK;
|
|
security_task_getsecid(current, &secid);
|
|
return process_measurement(file, current_cred(), secid, buf, size,
|
|
MAY_READ, func);
|
|
}
|
|
|
|
/**
|
|
* ima_load_data - appraise decision based on policy
|
|
* @id: kernel load data caller identifier
|
|
*
|
|
* Callers of this LSM hook can not measure, appraise, or audit the
|
|
* data provided by userspace. Enforce policy rules requring a file
|
|
* signature (eg. kexec'ed kernel image).
|
|
*
|
|
* For permission return 0, otherwise return -EACCES.
|
|
*/
|
|
int ima_load_data(enum kernel_load_data_id id)
|
|
{
|
|
bool ima_enforce, sig_enforce;
|
|
|
|
ima_enforce =
|
|
(ima_appraise & IMA_APPRAISE_ENFORCE) == IMA_APPRAISE_ENFORCE;
|
|
|
|
switch (id) {
|
|
case LOADING_KEXEC_IMAGE:
|
|
if (IS_ENABLED(CONFIG_KEXEC_SIG)
|
|
&& arch_ima_get_secureboot()) {
|
|
pr_err("impossible to appraise a kernel image without a file descriptor; try using kexec_file_load syscall.\n");
|
|
return -EACCES;
|
|
}
|
|
|
|
if (ima_enforce && (ima_appraise & IMA_APPRAISE_KEXEC)) {
|
|
pr_err("impossible to appraise a kernel image without a file descriptor; try using kexec_file_load syscall.\n");
|
|
return -EACCES; /* INTEGRITY_UNKNOWN */
|
|
}
|
|
break;
|
|
case LOADING_FIRMWARE:
|
|
if (ima_enforce && (ima_appraise & IMA_APPRAISE_FIRMWARE)) {
|
|
pr_err("Prevent firmware sysfs fallback loading.\n");
|
|
return -EACCES; /* INTEGRITY_UNKNOWN */
|
|
}
|
|
break;
|
|
case LOADING_MODULE:
|
|
sig_enforce = is_module_sig_enforced();
|
|
|
|
if (ima_enforce && (!sig_enforce
|
|
&& (ima_appraise & IMA_APPRAISE_MODULES))) {
|
|
pr_err("impossible to appraise a module without a file descriptor. sig_enforce kernel parameter might help\n");
|
|
return -EACCES; /* INTEGRITY_UNKNOWN */
|
|
}
|
|
default:
|
|
break;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* process_buffer_measurement - Measure the buffer to ima log.
|
|
* @buf: pointer to the buffer that needs to be added to the log.
|
|
* @size: size of buffer(in bytes).
|
|
* @eventname: event name to be used for the buffer entry.
|
|
* @cred: a pointer to a credentials structure for user validation.
|
|
* @secid: the secid of the task to be validated.
|
|
*
|
|
* Based on policy, the buffer is measured into the ima log.
|
|
*/
|
|
static void process_buffer_measurement(const void *buf, int size,
|
|
const char *eventname,
|
|
const struct cred *cred, u32 secid)
|
|
{
|
|
int ret = 0;
|
|
struct ima_template_entry *entry = NULL;
|
|
struct integrity_iint_cache iint = {};
|
|
struct ima_event_data event_data = {.iint = &iint,
|
|
.filename = eventname,
|
|
.buf = buf,
|
|
.buf_len = size};
|
|
struct ima_template_desc *template_desc = NULL;
|
|
struct {
|
|
struct ima_digest_data hdr;
|
|
char digest[IMA_MAX_DIGEST_SIZE];
|
|
} hash = {};
|
|
int violation = 0;
|
|
int pcr = CONFIG_IMA_MEASURE_PCR_IDX;
|
|
int action = 0;
|
|
|
|
action = ima_get_action(NULL, cred, secid, 0, KEXEC_CMDLINE, &pcr,
|
|
&template_desc);
|
|
if (!(action & IMA_MEASURE))
|
|
return;
|
|
|
|
iint.ima_hash = &hash.hdr;
|
|
iint.ima_hash->algo = ima_hash_algo;
|
|
iint.ima_hash->length = hash_digest_size[ima_hash_algo];
|
|
|
|
ret = ima_calc_buffer_hash(buf, size, iint.ima_hash);
|
|
if (ret < 0)
|
|
goto out;
|
|
|
|
ret = ima_alloc_init_template(&event_data, &entry, template_desc);
|
|
if (ret < 0)
|
|
goto out;
|
|
|
|
ret = ima_store_template(entry, violation, NULL, buf, pcr);
|
|
|
|
if (ret < 0)
|
|
ima_free_template_entry(entry);
|
|
|
|
out:
|
|
return;
|
|
}
|
|
|
|
/**
|
|
* ima_kexec_cmdline - measure kexec cmdline boot args
|
|
* @buf: pointer to buffer
|
|
* @size: size of buffer
|
|
*
|
|
* Buffers can only be measured, not appraised.
|
|
*/
|
|
void ima_kexec_cmdline(const void *buf, int size)
|
|
{
|
|
u32 secid;
|
|
|
|
if (buf && size != 0) {
|
|
security_task_getsecid(current, &secid);
|
|
process_buffer_measurement(buf, size, "kexec-cmdline",
|
|
current_cred(), secid);
|
|
}
|
|
}
|
|
|
|
static int __init init_ima(void)
|
|
{
|
|
int error;
|
|
|
|
ima_init_template_list();
|
|
hash_setup(CONFIG_IMA_DEFAULT_HASH);
|
|
error = ima_init();
|
|
|
|
if (error && strcmp(hash_algo_name[ima_hash_algo],
|
|
CONFIG_IMA_DEFAULT_HASH) != 0) {
|
|
pr_info("Allocating %s failed, going to use default hash algorithm %s\n",
|
|
hash_algo_name[ima_hash_algo], CONFIG_IMA_DEFAULT_HASH);
|
|
hash_setup_done = 0;
|
|
hash_setup(CONFIG_IMA_DEFAULT_HASH);
|
|
error = ima_init();
|
|
}
|
|
|
|
error = register_blocking_lsm_notifier(&ima_lsm_policy_notifier);
|
|
if (error)
|
|
pr_warn("Couldn't register LSM notifier, error %d\n", error);
|
|
|
|
if (!error)
|
|
ima_update_policy_flag();
|
|
|
|
return error;
|
|
}
|
|
|
|
late_initcall(init_ima); /* Start IMA after the TPM is available */
|