/*
* security/tomoyo/tomoyo.c
*
* LSM hooks for TOMOYO Linux.
*
* Copyright (C) 2005-2009 NTT DATA CORPORATION
*
* Version: 2.2.0-pre 2009/02/01
*
*/
#include <linux/security.h>
#include "common.h"
#include "tomoyo.h"
#include "realpath.h"
static int tomoyo_cred_prepare(struct cred *new, const struct cred *old,
gfp_t gfp)
{
/*
* Since "struct tomoyo_domain_info *" is a sharable pointer,
* we don't need to duplicate.
*/
new->security = old->security;
return 0;
}
static int tomoyo_bprm_set_creds(struct linux_binprm *bprm)
{
/*
* Do only if this function is called for the first time of an execve
* operation.
*/
if (bprm->cred_prepared)
return 0;
/*
* Load policy if /sbin/tomoyo-init exists and /sbin/init is requested
* for the first time.
*/
if (!tomoyo_policy_loaded)
tomoyo_load_policy(bprm->filename);
/*
* Tell tomoyo_bprm_check_security() is called for the first time of an
* execve operation.
*/
bprm->cred->security = NULL;
return 0;
}
static int tomoyo_bprm_check_security(struct linux_binprm *bprm)
{
struct tomoyo_domain_info *domain = bprm->cred->security;
/*
* Execute permission is checked against pathname passed to do_execve()
* using current domain.
*/
if (!domain) {
struct tomoyo_domain_info *next_domain = NULL;
int retval = tomoyo_find_next_domain(bprm, &next_domain);
if (!retval)
bprm->cred->security = next_domain;
return retval;
}
/*
* Read permission is checked against interpreters using next domain.
* '1' is the result of open_to_namei_flags(O_RDONLY).
*/
return tomoyo_check_open_permission(domain, &bprm->file->f_path, 1);
}
#ifdef CONFIG_SYSCTL
static int tomoyo_prepend(char **buffer, int *buflen, const char *str)
{
int namelen = strlen(str);
if (*buflen < namelen)
return -ENOMEM;
*buflen -= namelen;
*buffer -= namelen;
memcpy(*buffer, str, namelen);
return 0;
}
/**
* tomoyo_sysctl_path - return the realpath of a ctl_table.
* @table: pointer to "struct ctl_table".
*
* Returns realpath(3) of the @table on success.
* Returns NULL on failure.
*
* This function uses tomoyo_alloc(), so the caller must call tomoyo_free()
* if this function didn't return NULL.
*/
static char *tomoyo_sysctl_path(struct ctl_table *table)
{
int buflen = TOMOYO_MAX_PATHNAME_LEN;
char *buf = tomoyo_alloc(buflen);
char *end = buf + buflen;
int error = -ENOMEM;
if (!buf)
return NULL;
*--end = '\0';
buflen--;
while (table) {
char num[32];
const char *sp = table->procname;
if (!sp) {
memset(num, 0, sizeof(num));
snprintf(num, sizeof(num) - 1, "=%d=", table->ctl_name);
sp = num;
}
if (tomoyo_prepend(&end, &buflen, sp) ||
tomoyo_prepend(&end, &buflen, "/"))
goto out;
table = table->parent;
}
if (tomoyo_prepend(&end, &buflen, "/proc/sys"))
goto out;
error = tomoyo_encode(buf, end - buf, end);
out:
if (!error)
return buf;
tomoyo_free(buf);
return NULL;
}
static int tomoyo_sysctl(struct ctl_table *table, int op)
{
int error;
char *name;
op &= MAY_READ | MAY_WRITE;
if (!op)
return 0;
name = tomoyo_sysctl_path(table);
if (!name)
return -ENOMEM;
error = tomoyo_check_file_perm(tomoyo_domain(), name, op);
tomoyo_free(name);
return error;
}
#endif
static int tomoyo_path_truncate(struct path *path, loff_t length,
unsigned int time_attrs)
{
return tomoyo_check_1path_perm(tomoyo_domain(),
TOMOYO_TYPE_TRUNCATE_ACL,
path);
}
static int tomoyo_path_unlink(struct path *parent, struct dentry *dentry)
{
struct path path = { parent->mnt, dentry };
return tomoyo_check_1path_perm(tomoyo_domain(),
TOMOYO_TYPE_UNLINK_ACL,
&path);
}
static int tomoyo_path_mkdir(struct path *parent, struct dentry *dentry,
int mode)
{
struct path path = { parent->mnt, dentry };
return tomoyo_check_1path_perm(tomoyo_domain(),
TOMOYO_TYPE_MKDIR_ACL,
&path);
}
static int tomoyo_path_rmdir(struct path *parent, struct dentry *dentry)
{
struct path path = { parent->mnt, dentry };
return tomoyo_check_1path_perm(tomoyo_domain(),
TOMOYO_TYPE_RMDIR_ACL,
&path);
}
static int tomoyo_path_symlink(struct path *parent, struct dentry *dentry,
const char *old_name)
{
struct path path = { parent->mnt, dentry };
return tomoyo_check_1path_perm(tomoyo_domain(),
TOMOYO_TYPE_SYMLINK_ACL,
&path);
}
static int tomoyo_path_mknod(struct path *parent, struct dentry *dentry,
int mode, unsigned int dev)
{
struct path path = { parent->mnt, dentry };
int type = TOMOYO_TYPE_CREATE_ACL;
switch (mode & S_IFMT) {
case S_IFCHR:
type = TOMOYO_TYPE_MKCHAR_ACL;
break;
case S_IFBLK:
type = TOMOYO_TYPE_MKBLOCK_ACL;
break;
case S_IFIFO:
type = TOMOYO_TYPE_MKFIFO_ACL;
break;
case S_IFSOCK:
type = TOMOYO_TYPE_MKSOCK_ACL;
break;
}
return tomoyo_check_1path_perm(tomoyo_domain(),
type, &path);
}
static int tomoyo_path_link(struct dentry *old_dentry, struct path *new_dir,
struct dentry *new_dentry)
{
struct path path1 = { new_dir->mnt, old_dentry };
struct path path2 = { new_dir->mnt, new_dentry };
return tomoyo_check_2path_perm(tomoyo_domain(),
TOMOYO_TYPE_LINK_ACL,
&path1, &path2);
}
static int tomoyo_path_rename(struct path *old_parent,
struct dentry *old_dentry,
struct path *new_parent,
struct dentry *new_dentry)
{
struct path path1 = { old_parent->mnt, old_dentry };
struct path path2 = { new_parent->mnt, new_dentry };
return tomoyo_check_2path_perm(tomoyo_domain(),
TOMOYO_TYPE_RENAME_ACL,
&path1, &path2);
}
static int tomoyo_file_fcntl(struct file *file, unsigned int cmd,
unsigned long arg)
{
if (cmd == F_SETFL && ((arg ^ file->f_flags) & O_APPEND))
return tomoyo_check_rewrite_permission(tomoyo_domain(), file);
return 0;
}
static int tomoyo_dentry_open(struct file *f, const struct cred *cred)
{
int flags = f->f_flags;
if ((flags + 1) & O_ACCMODE)
flags++;
flags |= f->f_flags & (O_APPEND | O_TRUNC);
/* Don't check read permission here if called from do_execve(). */
if (current->in_execve)
return 0;
return tomoyo_check_open_permission(tomoyo_domain(), &f->f_path, flags);
}
static struct security_operations tomoyo_security_ops = {
.name = "tomoyo",
.cred_prepare = tomoyo_cred_prepare,
.bprm_set_creds = tomoyo_bprm_set_creds,
.bprm_check_security = tomoyo_bprm_check_security,
#ifdef CONFIG_SYSCTL
.sysctl = tomoyo_sysctl,
#endif
.file_fcntl = tomoyo_file_fcntl,
.dentry_open = tomoyo_dentry_open,
.path_truncate = tomoyo_path_truncate,
.path_unlink = tomoyo_path_unlink,
.path_mkdir = tomoyo_path_mkdir,
.path_rmdir = tomoyo_path_rmdir,
.path_symlink = tomoyo_path_symlink,
.path_mknod = tomoyo_path_mknod,
.path_link = tomoyo_path_link,
.path_rename = tomoyo_path_rename,
};
static int __init tomoyo_init(void)
{
struct cred *cred = (struct cred *) current_cred();
if (!security_module_enable(&tomoyo_security_ops))
return 0;
/* register ourselves with the security framework */
if (register_security(&tomoyo_security_ops))
panic("Failure registering TOMOYO Linux");
printk(KERN_INFO "TOMOYO Linux initialized\n");
cred->security = &tomoyo_kernel_domain;
tomoyo_realpath_init();
return 0;
}
security_initcall(tomoyo_init);
