mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-08 05:26:42 +07:00
acd0c93517
- As ima_counts_put() may be called after the inode has been freed, verify that the inode is not NULL, before dereferencing it. - Maintain the IMA file counters in may_open() properly, decrementing any counter increments on subsequent errors. Reported-by: Ciprian Docan <docan@eden.rutgers.edu> Reported-by: J.R. Okajima <hooanon05@yahoo.co.jp> Signed-off-by: Mimi Zohar <zohar@us.ibm.com> Acked-by: Eric Paris <eparis@redhat.com Signed-off-by: James Morris <jmorris@namei.org>
369 lines
9.3 KiB
C
369 lines
9.3 KiB
C
/*
|
|
* 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>
|
|
*
|
|
* 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.
|
|
*
|
|
* File: ima_main.c
|
|
* implements the IMA hooks: ima_bprm_check, ima_file_mmap,
|
|
* and ima_path_check.
|
|
*/
|
|
#include <linux/module.h>
|
|
#include <linux/file.h>
|
|
#include <linux/binfmts.h>
|
|
#include <linux/mount.h>
|
|
#include <linux/mman.h>
|
|
|
|
#include "ima.h"
|
|
|
|
int ima_initialized;
|
|
|
|
char *ima_hash = "sha1";
|
|
static int __init hash_setup(char *str)
|
|
{
|
|
if (strncmp(str, "md5", 3) == 0)
|
|
ima_hash = "md5";
|
|
return 1;
|
|
}
|
|
__setup("ima_hash=", hash_setup);
|
|
|
|
/**
|
|
* ima_file_free - called on __fput()
|
|
* @file: pointer to file structure being freed
|
|
*
|
|
* Flag files that changed, based on i_version;
|
|
* and decrement the iint readcount/writecount.
|
|
*/
|
|
void ima_file_free(struct file *file)
|
|
{
|
|
struct inode *inode = file->f_dentry->d_inode;
|
|
struct ima_iint_cache *iint;
|
|
|
|
if (!ima_initialized || !S_ISREG(inode->i_mode))
|
|
return;
|
|
iint = ima_iint_find_get(inode);
|
|
if (!iint)
|
|
return;
|
|
|
|
mutex_lock(&iint->mutex);
|
|
if (iint->opencount <= 0) {
|
|
printk(KERN_INFO
|
|
"%s: %s open/free imbalance (r:%ld w:%ld o:%ld f:%ld)\n",
|
|
__FUNCTION__, file->f_dentry->d_name.name,
|
|
iint->readcount, iint->writecount,
|
|
iint->opencount, atomic_long_read(&file->f_count));
|
|
if (!(iint->flags & IMA_IINT_DUMP_STACK)) {
|
|
dump_stack();
|
|
iint->flags |= IMA_IINT_DUMP_STACK;
|
|
}
|
|
}
|
|
iint->opencount--;
|
|
|
|
if ((file->f_mode & (FMODE_READ | FMODE_WRITE)) == FMODE_READ)
|
|
iint->readcount--;
|
|
|
|
if (file->f_mode & FMODE_WRITE) {
|
|
iint->writecount--;
|
|
if (iint->writecount == 0) {
|
|
if (iint->version != inode->i_version)
|
|
iint->flags &= ~IMA_MEASURED;
|
|
}
|
|
}
|
|
mutex_unlock(&iint->mutex);
|
|
kref_put(&iint->refcount, iint_free);
|
|
}
|
|
|
|
/* ima_read_write_check - reflect possible reading/writing errors in the PCR.
|
|
*
|
|
* When opening a file for read, if the file is already open for write,
|
|
* the file could change, resulting in a file measurement error.
|
|
*
|
|
* Opening a file for write, if the file is already open for read, results
|
|
* in a time of measure, time of use (ToMToU) error.
|
|
*
|
|
* In either case invalidate the PCR.
|
|
*/
|
|
enum iint_pcr_error { TOMTOU, OPEN_WRITERS };
|
|
static void ima_read_write_check(enum iint_pcr_error error,
|
|
struct ima_iint_cache *iint,
|
|
struct inode *inode,
|
|
const unsigned char *filename)
|
|
{
|
|
switch (error) {
|
|
case TOMTOU:
|
|
if (iint->readcount > 0)
|
|
ima_add_violation(inode, filename, "invalid_pcr",
|
|
"ToMToU");
|
|
break;
|
|
case OPEN_WRITERS:
|
|
if (iint->writecount > 0)
|
|
ima_add_violation(inode, filename, "invalid_pcr",
|
|
"open_writers");
|
|
break;
|
|
}
|
|
}
|
|
|
|
static int get_path_measurement(struct ima_iint_cache *iint, struct file *file,
|
|
const unsigned char *filename)
|
|
{
|
|
int rc = 0;
|
|
|
|
iint->opencount++;
|
|
iint->readcount++;
|
|
|
|
rc = ima_collect_measurement(iint, file);
|
|
if (!rc)
|
|
ima_store_measurement(iint, file, filename);
|
|
return rc;
|
|
}
|
|
|
|
static void ima_update_counts(struct ima_iint_cache *iint, int mask)
|
|
{
|
|
iint->opencount++;
|
|
if ((mask & MAY_WRITE) || (mask == 0))
|
|
iint->writecount++;
|
|
else if (mask & (MAY_READ | MAY_EXEC))
|
|
iint->readcount++;
|
|
}
|
|
|
|
/**
|
|
* ima_path_check - based on policy, collect/store measurement.
|
|
* @path: contains a pointer to the path to be measured
|
|
* @mask: contains MAY_READ, MAY_WRITE or MAY_EXECUTE
|
|
*
|
|
* Measure the file being open for readonly, based on the
|
|
* ima_must_measure() policy decision.
|
|
*
|
|
* Keep read/write counters for all files, but 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.
|
|
*
|
|
* Always return 0 and audit dentry_open failures.
|
|
* (Return code will be based upon measurement appraisal.)
|
|
*/
|
|
int ima_path_check(struct path *path, int mask, int update_counts)
|
|
{
|
|
struct inode *inode = path->dentry->d_inode;
|
|
struct ima_iint_cache *iint;
|
|
struct file *file = NULL;
|
|
int rc;
|
|
|
|
if (!ima_initialized || !S_ISREG(inode->i_mode))
|
|
return 0;
|
|
iint = ima_iint_find_insert_get(inode);
|
|
if (!iint)
|
|
return 0;
|
|
|
|
mutex_lock(&iint->mutex);
|
|
if (update_counts)
|
|
ima_update_counts(iint, mask);
|
|
|
|
rc = ima_must_measure(iint, inode, MAY_READ, PATH_CHECK);
|
|
if (rc < 0)
|
|
goto out;
|
|
|
|
if ((mask & MAY_WRITE) || (mask == 0))
|
|
ima_read_write_check(TOMTOU, iint, inode,
|
|
path->dentry->d_name.name);
|
|
|
|
if ((mask & (MAY_WRITE | MAY_READ | MAY_EXEC)) != MAY_READ)
|
|
goto out;
|
|
|
|
ima_read_write_check(OPEN_WRITERS, iint, inode,
|
|
path->dentry->d_name.name);
|
|
if (!(iint->flags & IMA_MEASURED)) {
|
|
struct dentry *dentry = dget(path->dentry);
|
|
struct vfsmount *mnt = mntget(path->mnt);
|
|
|
|
file = dentry_open(dentry, mnt, O_RDONLY | O_LARGEFILE,
|
|
current_cred());
|
|
if (IS_ERR(file)) {
|
|
int audit_info = 0;
|
|
|
|
integrity_audit_msg(AUDIT_INTEGRITY_PCR, inode,
|
|
dentry->d_name.name,
|
|
"add_measurement",
|
|
"dentry_open failed",
|
|
1, audit_info);
|
|
file = NULL;
|
|
goto out;
|
|
}
|
|
rc = get_path_measurement(iint, file, dentry->d_name.name);
|
|
}
|
|
out:
|
|
mutex_unlock(&iint->mutex);
|
|
if (file)
|
|
fput(file);
|
|
kref_put(&iint->refcount, iint_free);
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(ima_path_check);
|
|
|
|
static int process_measurement(struct file *file, const unsigned char *filename,
|
|
int mask, int function)
|
|
{
|
|
struct inode *inode = file->f_dentry->d_inode;
|
|
struct ima_iint_cache *iint;
|
|
int rc;
|
|
|
|
if (!ima_initialized || !S_ISREG(inode->i_mode))
|
|
return 0;
|
|
iint = ima_iint_find_insert_get(inode);
|
|
if (!iint)
|
|
return -ENOMEM;
|
|
|
|
mutex_lock(&iint->mutex);
|
|
rc = ima_must_measure(iint, inode, mask, function);
|
|
if (rc != 0)
|
|
goto out;
|
|
|
|
rc = ima_collect_measurement(iint, file);
|
|
if (!rc)
|
|
ima_store_measurement(iint, file, filename);
|
|
out:
|
|
mutex_unlock(&iint->mutex);
|
|
kref_put(&iint->refcount, iint_free);
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
* ima_counts_put - decrement file counts
|
|
*
|
|
* File counts are incremented in ima_path_check. On file open
|
|
* error, such as ETXTBSY, decrement the counts to prevent
|
|
* unnecessary imbalance messages.
|
|
*/
|
|
void ima_counts_put(struct path *path, int mask)
|
|
{
|
|
struct inode *inode = path->dentry->d_inode;
|
|
struct ima_iint_cache *iint;
|
|
|
|
/* The inode may already have been freed, freeing the iint
|
|
* with it. Verify the inode is not NULL before dereferencing
|
|
* it.
|
|
*/
|
|
if (!ima_initialized || !inode || !S_ISREG(inode->i_mode))
|
|
return;
|
|
iint = ima_iint_find_insert_get(inode);
|
|
if (!iint)
|
|
return;
|
|
|
|
mutex_lock(&iint->mutex);
|
|
iint->opencount--;
|
|
if ((mask & MAY_WRITE) || (mask == 0))
|
|
iint->writecount--;
|
|
else if (mask & (MAY_READ | MAY_EXEC))
|
|
iint->readcount--;
|
|
mutex_unlock(&iint->mutex);
|
|
|
|
kref_put(&iint->refcount, iint_free);
|
|
}
|
|
|
|
/*
|
|
* ima_counts_get - increment file counts
|
|
*
|
|
* - for IPC shm and shmat file.
|
|
* - for nfsd exported files.
|
|
*
|
|
* Increment the counts for these files to prevent unnecessary
|
|
* imbalance messages.
|
|
*/
|
|
void ima_counts_get(struct file *file)
|
|
{
|
|
struct inode *inode = file->f_dentry->d_inode;
|
|
struct ima_iint_cache *iint;
|
|
|
|
if (!ima_initialized || !S_ISREG(inode->i_mode))
|
|
return;
|
|
iint = ima_iint_find_insert_get(inode);
|
|
if (!iint)
|
|
return;
|
|
mutex_lock(&iint->mutex);
|
|
iint->opencount++;
|
|
if ((file->f_mode & (FMODE_READ | FMODE_WRITE)) == FMODE_READ)
|
|
iint->readcount++;
|
|
|
|
if (file->f_mode & FMODE_WRITE)
|
|
iint->writecount++;
|
|
mutex_unlock(&iint->mutex);
|
|
|
|
kref_put(&iint->refcount, iint_free);
|
|
}
|
|
EXPORT_SYMBOL_GPL(ima_counts_get);
|
|
|
|
/**
|
|
* 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.
|
|
*
|
|
* Return 0 on success, an error code on failure.
|
|
* (Based on the results of appraise_measurement().)
|
|
*/
|
|
int ima_file_mmap(struct file *file, unsigned long prot)
|
|
{
|
|
int rc;
|
|
|
|
if (!file)
|
|
return 0;
|
|
if (prot & PROT_EXEC)
|
|
rc = process_measurement(file, file->f_dentry->d_name.name,
|
|
MAY_EXEC, FILE_MMAP);
|
|
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.
|
|
*
|
|
* Return 0 on success, an error code on failure.
|
|
* (Based on the results of appraise_measurement().)
|
|
*/
|
|
int ima_bprm_check(struct linux_binprm *bprm)
|
|
{
|
|
int rc;
|
|
|
|
rc = process_measurement(bprm->file, bprm->filename,
|
|
MAY_EXEC, BPRM_CHECK);
|
|
return 0;
|
|
}
|
|
|
|
static int __init init_ima(void)
|
|
{
|
|
int error;
|
|
|
|
ima_iintcache_init();
|
|
error = ima_init();
|
|
ima_initialized = 1;
|
|
return error;
|
|
}
|
|
|
|
static void __exit cleanup_ima(void)
|
|
{
|
|
ima_cleanup();
|
|
}
|
|
|
|
late_initcall(init_ima); /* Start IMA after the TPM is available */
|
|
|
|
MODULE_DESCRIPTION("Integrity Measurement Architecture");
|
|
MODULE_LICENSE("GPL");
|