1
linux/security/selinux/selinuxfs.c

1810 lines
39 KiB
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/* Updated: Karl MacMillan <kmacmillan@tresys.com>
*
* Added conditional policy language extensions
*
* Updated: Hewlett-Packard <paul.moore@hp.com>
*
* Added support for the policy capability bitmap
*
* Copyright (C) 2007 Hewlett-Packard Development Company, L.P.
* Copyright (C) 2003 - 2004 Tresys Technology, LLC
* Copyright (C) 2004 Red Hat, Inc., James Morris <jmorris@redhat.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.
*/
#include <linux/kernel.h>
#include <linux/pagemap.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/fs.h>
#include <linux/mutex.h>
#include <linux/init.h>
#include <linux/string.h>
#include <linux/security.h>
#include <linux/major.h>
#include <linux/seq_file.h>
#include <linux/percpu.h>
#include <linux/audit.h>
#include <linux/uaccess.h>
/* selinuxfs pseudo filesystem for exporting the security policy API.
Based on the proc code and the fs/nfsd/nfsctl.c code. */
#include "flask.h"
#include "avc.h"
#include "avc_ss.h"
#include "security.h"
#include "objsec.h"
#include "conditional.h"
/* Policy capability filenames */
static char *policycap_names[] = {
"network_peer_controls",
"open_perms"
};
unsigned int selinux_checkreqprot = CONFIG_SECURITY_SELINUX_CHECKREQPROT_VALUE;
#ifdef CONFIG_SECURITY_SELINUX_ENABLE_SECMARK_DEFAULT
#define SELINUX_COMPAT_NET_VALUE 0
#else
#define SELINUX_COMPAT_NET_VALUE 1
#endif
int selinux_compat_net = SELINUX_COMPAT_NET_VALUE;
static int __init checkreqprot_setup(char *str)
{
unsigned long checkreqprot;
if (!strict_strtoul(str, 0, &checkreqprot))
selinux_checkreqprot = checkreqprot ? 1 : 0;
return 1;
}
__setup("checkreqprot=", checkreqprot_setup);
static int __init selinux_compat_net_setup(char *str)
{
unsigned long compat_net;
if (!strict_strtoul(str, 0, &compat_net))
selinux_compat_net = compat_net ? 1 : 0;
return 1;
}
__setup("selinux_compat_net=", selinux_compat_net_setup);
static DEFINE_MUTEX(sel_mutex);
/* global data for booleans */
static struct dentry *bool_dir;
static int bool_num;
static char **bool_pending_names;
static int *bool_pending_values;
/* global data for classes */
static struct dentry *class_dir;
static unsigned long last_class_ino;
/* global data for policy capabilities */
static struct dentry *policycap_dir;
extern void selnl_notify_setenforce(int val);
/* Check whether a task is allowed to use a security operation. */
static int task_has_security(struct task_struct *tsk,
u32 perms)
{
struct task_security_struct *tsec;
tsec = tsk->security;
if (!tsec)
return -EACCES;
return avc_has_perm(tsec->sid, SECINITSID_SECURITY,
SECCLASS_SECURITY, perms, NULL);
}
enum sel_inos {
SEL_ROOT_INO = 2,
SEL_LOAD, /* load policy */
SEL_ENFORCE, /* get or set enforcing status */
SEL_CONTEXT, /* validate context */
SEL_ACCESS, /* compute access decision */
SEL_CREATE, /* compute create labeling decision */
SEL_RELABEL, /* compute relabeling decision */
SEL_USER, /* compute reachable user contexts */
SEL_POLICYVERS, /* return policy version for this kernel */
SEL_COMMIT_BOOLS, /* commit new boolean values */
SEL_MLS, /* return if MLS policy is enabled */
SEL_DISABLE, /* disable SELinux until next reboot */
SEL_MEMBER, /* compute polyinstantiation membership decision */
SEL_CHECKREQPROT, /* check requested protection, not kernel-applied one */
SEL_COMPAT_NET, /* whether to use old compat network packet controls */
SEL_REJECT_UNKNOWN, /* export unknown reject handling to userspace */
SEL_DENY_UNKNOWN, /* export unknown deny handling to userspace */
SEL_INO_NEXT, /* The next inode number to use */
};
static unsigned long sel_last_ino = SEL_INO_NEXT - 1;
#define SEL_INITCON_INO_OFFSET 0x01000000
#define SEL_BOOL_INO_OFFSET 0x02000000
#define SEL_CLASS_INO_OFFSET 0x04000000
#define SEL_POLICYCAP_INO_OFFSET 0x08000000
#define SEL_INO_MASK 0x00ffffff
#define TMPBUFLEN 12
static ssize_t sel_read_enforce(struct file *filp, char __user *buf,
size_t count, loff_t *ppos)
{
char tmpbuf[TMPBUFLEN];
ssize_t length;
length = scnprintf(tmpbuf, TMPBUFLEN, "%d", selinux_enforcing);
return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
}
#ifdef CONFIG_SECURITY_SELINUX_DEVELOP
static ssize_t sel_write_enforce(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
char *page;
ssize_t length;
int new_value;
if (count >= PAGE_SIZE)
return -ENOMEM;
if (*ppos != 0) {
/* No partial writes. */
return -EINVAL;
}
page = (char *)get_zeroed_page(GFP_KERNEL);
if (!page)
return -ENOMEM;
length = -EFAULT;
if (copy_from_user(page, buf, count))
goto out;
length = -EINVAL;
if (sscanf(page, "%d", &new_value) != 1)
goto out;
if (new_value != selinux_enforcing) {
length = task_has_security(current, SECURITY__SETENFORCE);
if (length)
goto out;
audit_log(current->audit_context, GFP_KERNEL, AUDIT_MAC_STATUS,
"enforcing=%d old_enforcing=%d auid=%u ses=%u",
new_value, selinux_enforcing,
audit_get_loginuid(current),
audit_get_sessionid(current));
selinux_enforcing = new_value;
if (selinux_enforcing)
avc_ss_reset(0);
selnl_notify_setenforce(selinux_enforcing);
}
length = count;
out:
free_page((unsigned long) page);
return length;
}
#else
#define sel_write_enforce NULL
#endif
static const struct file_operations sel_enforce_ops = {
.read = sel_read_enforce,
.write = sel_write_enforce,
};
static ssize_t sel_read_handle_unknown(struct file *filp, char __user *buf,
size_t count, loff_t *ppos)
{
char tmpbuf[TMPBUFLEN];
ssize_t length;
ino_t ino = filp->f_path.dentry->d_inode->i_ino;
int handle_unknown = (ino == SEL_REJECT_UNKNOWN) ?
security_get_reject_unknown() : !security_get_allow_unknown();
length = scnprintf(tmpbuf, TMPBUFLEN, "%d", handle_unknown);
return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
}
static const struct file_operations sel_handle_unknown_ops = {
.read = sel_read_handle_unknown,
};
#ifdef CONFIG_SECURITY_SELINUX_DISABLE
static ssize_t sel_write_disable(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
char *page;
ssize_t length;
int new_value;
extern int selinux_disable(void);
if (count >= PAGE_SIZE)
return -ENOMEM;
if (*ppos != 0) {
/* No partial writes. */
return -EINVAL;
}
page = (char *)get_zeroed_page(GFP_KERNEL);
if (!page)
return -ENOMEM;
length = -EFAULT;
if (copy_from_user(page, buf, count))
goto out;
length = -EINVAL;
if (sscanf(page, "%d", &new_value) != 1)
goto out;
if (new_value) {
length = selinux_disable();
if (length < 0)
goto out;
audit_log(current->audit_context, GFP_KERNEL, AUDIT_MAC_STATUS,
"selinux=0 auid=%u ses=%u",
audit_get_loginuid(current),
audit_get_sessionid(current));
}
length = count;
out:
free_page((unsigned long) page);
return length;
}
#else
#define sel_write_disable NULL
#endif
static const struct file_operations sel_disable_ops = {
.write = sel_write_disable,
};
static ssize_t sel_read_policyvers(struct file *filp, char __user *buf,
size_t count, loff_t *ppos)
{
char tmpbuf[TMPBUFLEN];
ssize_t length;
length = scnprintf(tmpbuf, TMPBUFLEN, "%u", POLICYDB_VERSION_MAX);
return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
}
static const struct file_operations sel_policyvers_ops = {
.read = sel_read_policyvers,
};
/* declaration for sel_write_load */
static int sel_make_bools(void);
static int sel_make_classes(void);
static int sel_make_policycap(void);
/* declaration for sel_make_class_dirs */
static int sel_make_dir(struct inode *dir, struct dentry *dentry,
unsigned long *ino);
static ssize_t sel_read_mls(struct file *filp, char __user *buf,
size_t count, loff_t *ppos)
{
char tmpbuf[TMPBUFLEN];
ssize_t length;
length = scnprintf(tmpbuf, TMPBUFLEN, "%d", selinux_mls_enabled);
return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
}
static const struct file_operations sel_mls_ops = {
.read = sel_read_mls,
};
static ssize_t sel_write_load(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
int ret;
ssize_t length;
void *data = NULL;
mutex_lock(&sel_mutex);
length = task_has_security(current, SECURITY__LOAD_POLICY);
if (length)
goto out;
if (*ppos != 0) {
/* No partial writes. */
length = -EINVAL;
goto out;
}
if ((count > 64 * 1024 * 1024)
|| (data = vmalloc(count)) == NULL) {
length = -ENOMEM;
goto out;
}
length = -EFAULT;
if (copy_from_user(data, buf, count) != 0)
goto out;
length = security_load_policy(data, count);
if (length)
goto out;
ret = sel_make_bools();
if (ret) {
length = ret;
goto out1;
}
ret = sel_make_classes();
if (ret) {
length = ret;
goto out1;
}
ret = sel_make_policycap();
if (ret)
length = ret;
else
length = count;
out1:
audit_log(current->audit_context, GFP_KERNEL, AUDIT_MAC_POLICY_LOAD,
"policy loaded auid=%u ses=%u",
audit_get_loginuid(current),
audit_get_sessionid(current));
out:
mutex_unlock(&sel_mutex);
vfree(data);
return length;
}
static const struct file_operations sel_load_ops = {
.write = sel_write_load,
};
static ssize_t sel_write_context(struct file *file, char *buf, size_t size)
{
char *canon;
u32 sid, len;
ssize_t length;
length = task_has_security(current, SECURITY__CHECK_CONTEXT);
if (length)
return length;
length = security_context_to_sid(buf, size, &sid);
if (length < 0)
return length;
length = security_sid_to_context(sid, &canon, &len);
if (length < 0)
return length;
if (len > SIMPLE_TRANSACTION_LIMIT) {
printk(KERN_ERR "SELinux: %s: context size (%u) exceeds "
"payload max\n", __func__, len);
length = -ERANGE;
goto out;
}
memcpy(buf, canon, len);
length = len;
out:
kfree(canon);
return length;
}
static ssize_t sel_read_checkreqprot(struct file *filp, char __user *buf,
size_t count, loff_t *ppos)
{
char tmpbuf[TMPBUFLEN];
ssize_t length;
length = scnprintf(tmpbuf, TMPBUFLEN, "%u", selinux_checkreqprot);
return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
}
static ssize_t sel_write_checkreqprot(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
char *page;
ssize_t length;
unsigned int new_value;
length = task_has_security(current, SECURITY__SETCHECKREQPROT);
if (length)
return length;
if (count >= PAGE_SIZE)
return -ENOMEM;
if (*ppos != 0) {
/* No partial writes. */
return -EINVAL;
}
page = (char *)get_zeroed_page(GFP_KERNEL);
if (!page)
return -ENOMEM;
length = -EFAULT;
if (copy_from_user(page, buf, count))
goto out;
length = -EINVAL;
if (sscanf(page, "%u", &new_value) != 1)
goto out;
selinux_checkreqprot = new_value ? 1 : 0;
length = count;
out:
free_page((unsigned long) page);
return length;
}
static const struct file_operations sel_checkreqprot_ops = {
.read = sel_read_checkreqprot,
.write = sel_write_checkreqprot,
};
static ssize_t sel_read_compat_net(struct file *filp, char __user *buf,
size_t count, loff_t *ppos)
{
char tmpbuf[TMPBUFLEN];
ssize_t length;
length = scnprintf(tmpbuf, TMPBUFLEN, "%d", selinux_compat_net);
return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
}
static ssize_t sel_write_compat_net(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
char *page;
ssize_t length;
int new_value;
length = task_has_security(current, SECURITY__LOAD_POLICY);
if (length)
return length;
if (count >= PAGE_SIZE)
return -ENOMEM;
if (*ppos != 0) {
/* No partial writes. */
return -EINVAL;
}
page = (char *)get_zeroed_page(GFP_KERNEL);
if (!page)
return -ENOMEM;
length = -EFAULT;
if (copy_from_user(page, buf, count))
goto out;
length = -EINVAL;
if (sscanf(page, "%d", &new_value) != 1)
goto out;
selinux_compat_net = new_value ? 1 : 0;
length = count;
out:
free_page((unsigned long) page);
return length;
}
static const struct file_operations sel_compat_net_ops = {
.read = sel_read_compat_net,
.write = sel_write_compat_net,
};
/*
* Remaining nodes use transaction based IO methods like nfsd/nfsctl.c
*/
static ssize_t sel_write_access(struct file *file, char *buf, size_t size);
static ssize_t sel_write_create(struct file *file, char *buf, size_t size);
static ssize_t sel_write_relabel(struct file *file, char *buf, size_t size);
static ssize_t sel_write_user(struct file *file, char *buf, size_t size);
static ssize_t sel_write_member(struct file *file, char *buf, size_t size);
static ssize_t (*write_op[])(struct file *, char *, size_t) = {
[SEL_ACCESS] = sel_write_access,
[SEL_CREATE] = sel_write_create,
[SEL_RELABEL] = sel_write_relabel,
[SEL_USER] = sel_write_user,
[SEL_MEMBER] = sel_write_member,
[SEL_CONTEXT] = sel_write_context,
};
static ssize_t selinux_transaction_write(struct file *file, const char __user *buf, size_t size, loff_t *pos)
{
ino_t ino = file->f_path.dentry->d_inode->i_ino;
char *data;
ssize_t rv;
if (ino >= ARRAY_SIZE(write_op) || !write_op[ino])
return -EINVAL;
data = simple_transaction_get(file, buf, size);
if (IS_ERR(data))
return PTR_ERR(data);
rv = write_op[ino](file, data, size);
if (rv > 0) {
simple_transaction_set(file, rv);
rv = size;
}
return rv;
}
static const struct file_operations transaction_ops = {
.write = selinux_transaction_write,
.read = simple_transaction_read,
.release = simple_transaction_release,
};
/*
* payload - write methods
* If the method has a response, the response should be put in buf,
* and the length returned. Otherwise return 0 or and -error.
*/
static ssize_t sel_write_access(struct file *file, char *buf, size_t size)
{
char *scon, *tcon;
u32 ssid, tsid;
u16 tclass;
u32 req;
struct av_decision avd;
ssize_t length;
length = task_has_security(current, SECURITY__COMPUTE_AV);
if (length)
return length;
length = -ENOMEM;
scon = kzalloc(size+1, GFP_KERNEL);
if (!scon)
return length;
tcon = kzalloc(size+1, GFP_KERNEL);
if (!tcon)
goto out;
length = -EINVAL;
if (sscanf(buf, "%s %s %hu %x", scon, tcon, &tclass, &req) != 4)
goto out2;
length = security_context_to_sid(scon, strlen(scon)+1, &ssid);
if (length < 0)
goto out2;
length = security_context_to_sid(tcon, strlen(tcon)+1, &tsid);
if (length < 0)
goto out2;
length = security_compute_av(ssid, tsid, tclass, req, &avd);
if (length < 0)
goto out2;
length = scnprintf(buf, SIMPLE_TRANSACTION_LIMIT,
"%x %x %x %x %u",
avd.allowed, avd.decided,
avd.auditallow, avd.auditdeny,
avd.seqno);
out2:
kfree(tcon);
out:
kfree(scon);
return length;
}
static ssize_t sel_write_create(struct file *file, char *buf, size_t size)
{
char *scon, *tcon;
u32 ssid, tsid, newsid;
u16 tclass;
ssize_t length;
char *newcon;
u32 len;
length = task_has_security(current, SECURITY__COMPUTE_CREATE);
if (length)
return length;
length = -ENOMEM;
scon = kzalloc(size+1, GFP_KERNEL);
if (!scon)
return length;
tcon = kzalloc(size+1, GFP_KERNEL);
if (!tcon)
goto out;
length = -EINVAL;
if (sscanf(buf, "%s %s %hu", scon, tcon, &tclass) != 3)
goto out2;
length = security_context_to_sid(scon, strlen(scon)+1, &ssid);
if (length < 0)
goto out2;
length = security_context_to_sid(tcon, strlen(tcon)+1, &tsid);
if (length < 0)
goto out2;
length = security_transition_sid(ssid, tsid, tclass, &newsid);
if (length < 0)
goto out2;
length = security_sid_to_context(newsid, &newcon, &len);
if (length < 0)
goto out2;
if (len > SIMPLE_TRANSACTION_LIMIT) {
printk(KERN_ERR "SELinux: %s: context size (%u) exceeds "
"payload max\n", __func__, len);
length = -ERANGE;
goto out3;
}
memcpy(buf, newcon, len);
length = len;
out3:
kfree(newcon);
out2:
kfree(tcon);
out:
kfree(scon);
return length;
}
static ssize_t sel_write_relabel(struct file *file, char *buf, size_t size)
{
char *scon, *tcon;
u32 ssid, tsid, newsid;
u16 tclass;
ssize_t length;
char *newcon;
u32 len;
length = task_has_security(current, SECURITY__COMPUTE_RELABEL);
if (length)
return length;
length = -ENOMEM;
scon = kzalloc(size+1, GFP_KERNEL);
if (!scon)
return length;
tcon = kzalloc(size+1, GFP_KERNEL);
if (!tcon)
goto out;
length = -EINVAL;
if (sscanf(buf, "%s %s %hu", scon, tcon, &tclass) != 3)
goto out2;
length = security_context_to_sid(scon, strlen(scon)+1, &ssid);
if (length < 0)
goto out2;
length = security_context_to_sid(tcon, strlen(tcon)+1, &tsid);
if (length < 0)
goto out2;
length = security_change_sid(ssid, tsid, tclass, &newsid);
if (length < 0)
goto out2;
length = security_sid_to_context(newsid, &newcon, &len);
if (length < 0)
goto out2;
if (len > SIMPLE_TRANSACTION_LIMIT) {
length = -ERANGE;
goto out3;
}
memcpy(buf, newcon, len);
length = len;
out3:
kfree(newcon);
out2:
kfree(tcon);
out:
kfree(scon);
return length;
}
static ssize_t sel_write_user(struct file *file, char *buf, size_t size)
{
char *con, *user, *ptr;
u32 sid, *sids;
ssize_t length;
char *newcon;
int i, rc;
u32 len, nsids;
length = task_has_security(current, SECURITY__COMPUTE_USER);
if (length)
return length;
length = -ENOMEM;
con = kzalloc(size+1, GFP_KERNEL);
if (!con)
return length;
user = kzalloc(size+1, GFP_KERNEL);
if (!user)
goto out;
length = -EINVAL;
if (sscanf(buf, "%s %s", con, user) != 2)
goto out2;
length = security_context_to_sid(con, strlen(con)+1, &sid);
if (length < 0)
goto out2;
length = security_get_user_sids(sid, user, &sids, &nsids);
if (length < 0)
goto out2;
length = sprintf(buf, "%u", nsids) + 1;
ptr = buf + length;
for (i = 0; i < nsids; i++) {
rc = security_sid_to_context(sids[i], &newcon, &len);
if (rc) {
length = rc;
goto out3;
}
if ((length + len) >= SIMPLE_TRANSACTION_LIMIT) {
kfree(newcon);
length = -ERANGE;
goto out3;
}
memcpy(ptr, newcon, len);
kfree(newcon);
ptr += len;
length += len;
}
out3:
kfree(sids);
out2:
kfree(user);
out:
kfree(con);
return length;
}
static ssize_t sel_write_member(struct file *file, char *buf, size_t size)
{
char *scon, *tcon;
u32 ssid, tsid, newsid;
u16 tclass;
ssize_t length;
char *newcon;
u32 len;
length = task_has_security(current, SECURITY__COMPUTE_MEMBER);
if (length)
return length;
length = -ENOMEM;
scon = kzalloc(size+1, GFP_KERNEL);
if (!scon)
return length;
tcon = kzalloc(size+1, GFP_KERNEL);
if (!tcon)
goto out;
length = -EINVAL;
if (sscanf(buf, "%s %s %hu", scon, tcon, &tclass) != 3)
goto out2;
length = security_context_to_sid(scon, strlen(scon)+1, &ssid);
if (length < 0)
goto out2;
length = security_context_to_sid(tcon, strlen(tcon)+1, &tsid);
if (length < 0)
goto out2;
length = security_member_sid(ssid, tsid, tclass, &newsid);
if (length < 0)
goto out2;
length = security_sid_to_context(newsid, &newcon, &len);
if (length < 0)
goto out2;
if (len > SIMPLE_TRANSACTION_LIMIT) {
printk(KERN_ERR "SELinux: %s: context size (%u) exceeds "
"payload max\n", __func__, len);
length = -ERANGE;
goto out3;
}
memcpy(buf, newcon, len);
length = len;
out3:
kfree(newcon);
out2:
kfree(tcon);
out:
kfree(scon);
return length;
}
static struct inode *sel_make_inode(struct super_block *sb, int mode)
{
struct inode *ret = new_inode(sb);
if (ret) {
ret->i_mode = mode;
ret->i_uid = ret->i_gid = 0;
ret->i_blocks = 0;
ret->i_atime = ret->i_mtime = ret->i_ctime = CURRENT_TIME;
}
return ret;
}
static ssize_t sel_read_bool(struct file *filep, char __user *buf,
size_t count, loff_t *ppos)
{
char *page = NULL;
ssize_t length;
ssize_t ret;
int cur_enforcing;
struct inode *inode = filep->f_path.dentry->d_inode;
unsigned index = inode->i_ino & SEL_INO_MASK;
const char *name = filep->f_path.dentry->d_name.name;
mutex_lock(&sel_mutex);
if (index >= bool_num || strcmp(name, bool_pending_names[index])) {
ret = -EINVAL;
goto out;
}
if (count > PAGE_SIZE) {
ret = -EINVAL;
goto out;
}
page = (char *)get_zeroed_page(GFP_KERNEL);
if (!page) {
ret = -ENOMEM;
goto out;
}
cur_enforcing = security_get_bool_value(index);
if (cur_enforcing < 0) {
ret = cur_enforcing;
goto out;
}
length = scnprintf(page, PAGE_SIZE, "%d %d", cur_enforcing,
bool_pending_values[index]);
ret = simple_read_from_buffer(buf, count, ppos, page, length);
out:
mutex_unlock(&sel_mutex);
if (page)
free_page((unsigned long)page);
return ret;
}
static ssize_t sel_write_bool(struct file *filep, const char __user *buf,
size_t count, loff_t *ppos)
{
char *page = NULL;
ssize_t length;
int new_value;
struct inode *inode = filep->f_path.dentry->d_inode;
unsigned index = inode->i_ino & SEL_INO_MASK;
const char *name = filep->f_path.dentry->d_name.name;
mutex_lock(&sel_mutex);
length = task_has_security(current, SECURITY__SETBOOL);
if (length)
goto out;
if (index >= bool_num || strcmp(name, bool_pending_names[index])) {
length = -EINVAL;
goto out;
}
if (count >= PAGE_SIZE) {
length = -ENOMEM;
goto out;
}
if (*ppos != 0) {
/* No partial writes. */
length = -EINVAL;
goto out;
}
page = (char *)get_zeroed_page(GFP_KERNEL);
if (!page) {
length = -ENOMEM;
goto out;
}
length = -EFAULT;
if (copy_from_user(page, buf, count))
goto out;
length = -EINVAL;
if (sscanf(page, "%d", &new_value) != 1)
goto out;
if (new_value)
new_value = 1;
bool_pending_values[index] = new_value;
length = count;
out:
mutex_unlock(&sel_mutex);
if (page)
free_page((unsigned long) page);
return length;
}
static const struct file_operations sel_bool_ops = {
.read = sel_read_bool,
.write = sel_write_bool,
};
static ssize_t sel_commit_bools_write(struct file *filep,
const char __user *buf,
size_t count, loff_t *ppos)
{
char *page = NULL;
ssize_t length;
int new_value;
mutex_lock(&sel_mutex);
length = task_has_security(current, SECURITY__SETBOOL);
if (length)
goto out;
if (count >= PAGE_SIZE) {
length = -ENOMEM;
goto out;
}
if (*ppos != 0) {
/* No partial writes. */
goto out;
}
page = (char *)get_zeroed_page(GFP_KERNEL);
if (!page) {
length = -ENOMEM;
goto out;
}
length = -EFAULT;
if (copy_from_user(page, buf, count))
goto out;
length = -EINVAL;
if (sscanf(page, "%d", &new_value) != 1)
goto out;
if (new_value && bool_pending_values)
security_set_bools(bool_num, bool_pending_values);
length = count;
out:
mutex_unlock(&sel_mutex);
if (page)
free_page((unsigned long) page);
return length;
}
static const struct file_operations sel_commit_bools_ops = {
.write = sel_commit_bools_write,
};
static void sel_remove_entries(struct dentry *de)
{
struct list_head *node;
spin_lock(&dcache_lock);
node = de->d_subdirs.next;
while (node != &de->d_subdirs) {
[PATCH] shrink dentry struct Some long time ago, dentry struct was carefully tuned so that on 32 bits UP, sizeof(struct dentry) was exactly 128, ie a power of 2, and a multiple of memory cache lines. Then RCU was added and dentry struct enlarged by two pointers, with nice results for SMP, but not so good on UP, because breaking the above tuning (128 + 8 = 136 bytes) This patch reverts this unwanted side effect, by using an union (d_u), where d_rcu and d_child are placed so that these two fields can share their memory needs. At the time d_free() is called (and d_rcu is really used), d_child is known to be empty and not touched by the dentry freeing. Lockless lookups only access d_name, d_parent, d_lock, d_op, d_flags (so the previous content of d_child is not needed if said dentry was unhashed but still accessed by a CPU because of RCU constraints) As dentry cache easily contains millions of entries, a size reduction is worth the extra complexity of the ugly C union. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Cc: Dipankar Sarma <dipankar@in.ibm.com> Cc: Maneesh Soni <maneesh@in.ibm.com> Cc: Miklos Szeredi <miklos@szeredi.hu> Cc: "Paul E. McKenney" <paulmck@us.ibm.com> Cc: Ian Kent <raven@themaw.net> Cc: Paul Jackson <pj@sgi.com> Cc: Al Viro <viro@ftp.linux.org.uk> Cc: Christoph Hellwig <hch@lst.de> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Cc: Neil Brown <neilb@cse.unsw.edu.au> Cc: James Morris <jmorris@namei.org> Cc: Stephen Smalley <sds@epoch.ncsc.mil> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-08 02:03:32 -07:00
struct dentry *d = list_entry(node, struct dentry, d_u.d_child);
list_del_init(node);
if (d->d_inode) {
d = dget_locked(d);
spin_unlock(&dcache_lock);
d_delete(d);
simple_unlink(de->d_inode, d);
dput(d);
spin_lock(&dcache_lock);
}
node = de->d_subdirs.next;
}
spin_unlock(&dcache_lock);
}
#define BOOL_DIR_NAME "booleans"
static int sel_make_bools(void)
{
int i, ret = 0;
ssize_t len;
struct dentry *dentry = NULL;
struct dentry *dir = bool_dir;
struct inode *inode = NULL;
struct inode_security_struct *isec;
char **names = NULL, *page;
int num;
int *values = NULL;
u32 sid;
/* remove any existing files */
kfree(bool_pending_names);
kfree(bool_pending_values);
bool_pending_names = NULL;
bool_pending_values = NULL;
sel_remove_entries(dir);
page = (char *)get_zeroed_page(GFP_KERNEL);
if (!page)
return -ENOMEM;
ret = security_get_bools(&num, &names, &values);
if (ret != 0)
goto out;
for (i = 0; i < num; i++) {
dentry = d_alloc_name(dir, names[i]);
if (!dentry) {
ret = -ENOMEM;
goto err;
}
inode = sel_make_inode(dir->d_sb, S_IFREG | S_IRUGO | S_IWUSR);
if (!inode) {
ret = -ENOMEM;
goto err;
}
len = snprintf(page, PAGE_SIZE, "/%s/%s", BOOL_DIR_NAME, names[i]);
if (len < 0) {
ret = -EINVAL;
goto err;
} else if (len >= PAGE_SIZE) {
ret = -ENAMETOOLONG;
goto err;
}
isec = (struct inode_security_struct *)inode->i_security;
ret = security_genfs_sid("selinuxfs", page, SECCLASS_FILE, &sid);
if (ret)
goto err;
isec->sid = sid;
isec->initialized = 1;
inode->i_fop = &sel_bool_ops;
inode->i_ino = i|SEL_BOOL_INO_OFFSET;
d_add(dentry, inode);
}
bool_num = num;
bool_pending_names = names;
bool_pending_values = values;
out:
free_page((unsigned long)page);
return ret;
err:
if (names) {
for (i = 0; i < num; i++)
kfree(names[i]);
kfree(names);
}
kfree(values);
sel_remove_entries(dir);
ret = -ENOMEM;
goto out;
}
#define NULL_FILE_NAME "null"
struct dentry *selinux_null;
static ssize_t sel_read_avc_cache_threshold(struct file *filp, char __user *buf,
size_t count, loff_t *ppos)
{
char tmpbuf[TMPBUFLEN];
ssize_t length;
length = scnprintf(tmpbuf, TMPBUFLEN, "%u", avc_cache_threshold);
return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
}
static ssize_t sel_write_avc_cache_threshold(struct file *file,
const char __user *buf,
size_t count, loff_t *ppos)
{
char *page;
ssize_t ret;
int new_value;
if (count >= PAGE_SIZE) {
ret = -ENOMEM;
goto out;
}
if (*ppos != 0) {
/* No partial writes. */
ret = -EINVAL;
goto out;
}
page = (char *)get_zeroed_page(GFP_KERNEL);
if (!page) {
ret = -ENOMEM;
goto out;
}
if (copy_from_user(page, buf, count)) {
ret = -EFAULT;
goto out_free;
}
if (sscanf(page, "%u", &new_value) != 1) {
ret = -EINVAL;
goto out;
}
if (new_value != avc_cache_threshold) {
ret = task_has_security(current, SECURITY__SETSECPARAM);
if (ret)
goto out_free;
avc_cache_threshold = new_value;
}
ret = count;
out_free:
free_page((unsigned long)page);
out:
return ret;
}
static ssize_t sel_read_avc_hash_stats(struct file *filp, char __user *buf,
size_t count, loff_t *ppos)
{
char *page;
ssize_t ret = 0;
page = (char *)__get_free_page(GFP_KERNEL);
if (!page) {
ret = -ENOMEM;
goto out;
}
ret = avc_get_hash_stats(page);
if (ret >= 0)
ret = simple_read_from_buffer(buf, count, ppos, page, ret);
free_page((unsigned long)page);
out:
return ret;
}
static const struct file_operations sel_avc_cache_threshold_ops = {
.read = sel_read_avc_cache_threshold,
.write = sel_write_avc_cache_threshold,
};
static const struct file_operations sel_avc_hash_stats_ops = {
.read = sel_read_avc_hash_stats,
};
#ifdef CONFIG_SECURITY_SELINUX_AVC_STATS
static struct avc_cache_stats *sel_avc_get_stat_idx(loff_t *idx)
{
int cpu;
for (cpu = *idx; cpu < NR_CPUS; ++cpu) {
if (!cpu_possible(cpu))
continue;
*idx = cpu + 1;
return &per_cpu(avc_cache_stats, cpu);
}
return NULL;
}
static void *sel_avc_stats_seq_start(struct seq_file *seq, loff_t *pos)
{
loff_t n = *pos - 1;
if (*pos == 0)
return SEQ_START_TOKEN;
return sel_avc_get_stat_idx(&n);
}
static void *sel_avc_stats_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
return sel_avc_get_stat_idx(pos);
}
static int sel_avc_stats_seq_show(struct seq_file *seq, void *v)
{
struct avc_cache_stats *st = v;
if (v == SEQ_START_TOKEN)
seq_printf(seq, "lookups hits misses allocations reclaims "
"frees\n");
else
seq_printf(seq, "%u %u %u %u %u %u\n", st->lookups,
st->hits, st->misses, st->allocations,
st->reclaims, st->frees);
return 0;
}
static void sel_avc_stats_seq_stop(struct seq_file *seq, void *v)
{ }
static const struct seq_operations sel_avc_cache_stats_seq_ops = {
.start = sel_avc_stats_seq_start,
.next = sel_avc_stats_seq_next,
.show = sel_avc_stats_seq_show,
.stop = sel_avc_stats_seq_stop,
};
static int sel_open_avc_cache_stats(struct inode *inode, struct file *file)
{
return seq_open(file, &sel_avc_cache_stats_seq_ops);
}
static const struct file_operations sel_avc_cache_stats_ops = {
.open = sel_open_avc_cache_stats,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release,
};
#endif
static int sel_make_avc_files(struct dentry *dir)
{
int i, ret = 0;
static struct tree_descr files[] = {
{ "cache_threshold",
&sel_avc_cache_threshold_ops, S_IRUGO|S_IWUSR },
{ "hash_stats", &sel_avc_hash_stats_ops, S_IRUGO },
#ifdef CONFIG_SECURITY_SELINUX_AVC_STATS
{ "cache_stats", &sel_avc_cache_stats_ops, S_IRUGO },
#endif
};
for (i = 0; i < ARRAY_SIZE(files); i++) {
struct inode *inode;
struct dentry *dentry;
dentry = d_alloc_name(dir, files[i].name);
if (!dentry) {
ret = -ENOMEM;
goto out;
}
inode = sel_make_inode(dir->d_sb, S_IFREG|files[i].mode);
if (!inode) {
ret = -ENOMEM;
goto out;
}
inode->i_fop = files[i].ops;
inode->i_ino = ++sel_last_ino;
d_add(dentry, inode);
}
out:
return ret;
}
static ssize_t sel_read_initcon(struct file *file, char __user *buf,
size_t count, loff_t *ppos)
{
struct inode *inode;
char *con;
u32 sid, len;
ssize_t ret;
inode = file->f_path.dentry->d_inode;
sid = inode->i_ino&SEL_INO_MASK;
ret = security_sid_to_context(sid, &con, &len);
if (ret < 0)
return ret;
ret = simple_read_from_buffer(buf, count, ppos, con, len);
kfree(con);
return ret;
}
static const struct file_operations sel_initcon_ops = {
.read = sel_read_initcon,
};
static int sel_make_initcon_files(struct dentry *dir)
{
int i, ret = 0;
for (i = 1; i <= SECINITSID_NUM; i++) {
struct inode *inode;
struct dentry *dentry;
dentry = d_alloc_name(dir, security_get_initial_sid_context(i));
if (!dentry) {
ret = -ENOMEM;
goto out;
}
inode = sel_make_inode(dir->d_sb, S_IFREG|S_IRUGO);
if (!inode) {
ret = -ENOMEM;
goto out;
}
inode->i_fop = &sel_initcon_ops;
inode->i_ino = i|SEL_INITCON_INO_OFFSET;
d_add(dentry, inode);
}
out:
return ret;
}
static inline unsigned int sel_div(unsigned long a, unsigned long b)
{
return a / b - (a % b < 0);
}
static inline unsigned long sel_class_to_ino(u16 class)
{
return (class * (SEL_VEC_MAX + 1)) | SEL_CLASS_INO_OFFSET;
}
static inline u16 sel_ino_to_class(unsigned long ino)
{
return sel_div(ino & SEL_INO_MASK, SEL_VEC_MAX + 1);
}
static inline unsigned long sel_perm_to_ino(u16 class, u32 perm)
{
return (class * (SEL_VEC_MAX + 1) + perm) | SEL_CLASS_INO_OFFSET;
}
static inline u32 sel_ino_to_perm(unsigned long ino)
{
return (ino & SEL_INO_MASK) % (SEL_VEC_MAX + 1);
}
static ssize_t sel_read_class(struct file *file, char __user *buf,
size_t count, loff_t *ppos)
{
ssize_t rc, len;
char *page;
unsigned long ino = file->f_path.dentry->d_inode->i_ino;
page = (char *)__get_free_page(GFP_KERNEL);
if (!page) {
rc = -ENOMEM;
goto out;
}
len = snprintf(page, PAGE_SIZE, "%d", sel_ino_to_class(ino));
rc = simple_read_from_buffer(buf, count, ppos, page, len);
free_page((unsigned long)page);
out:
return rc;
}
static const struct file_operations sel_class_ops = {
.read = sel_read_class,
};
static ssize_t sel_read_perm(struct file *file, char __user *buf,
size_t count, loff_t *ppos)
{
ssize_t rc, len;
char *page;
unsigned long ino = file->f_path.dentry->d_inode->i_ino;
page = (char *)__get_free_page(GFP_KERNEL);
if (!page) {
rc = -ENOMEM;
goto out;
}
len = snprintf(page, PAGE_SIZE, "%d", sel_ino_to_perm(ino));
rc = simple_read_from_buffer(buf, count, ppos, page, len);
free_page((unsigned long)page);
out:
return rc;
}
static const struct file_operations sel_perm_ops = {
.read = sel_read_perm,
};
static ssize_t sel_read_policycap(struct file *file, char __user *buf,
size_t count, loff_t *ppos)
{
int value;
char tmpbuf[TMPBUFLEN];
ssize_t length;
unsigned long i_ino = file->f_path.dentry->d_inode->i_ino;
value = security_policycap_supported(i_ino & SEL_INO_MASK);
length = scnprintf(tmpbuf, TMPBUFLEN, "%d", value);
return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
}
static const struct file_operations sel_policycap_ops = {
.read = sel_read_policycap,
};
static int sel_make_perm_files(char *objclass, int classvalue,
struct dentry *dir)
{
int i, rc = 0, nperms;
char **perms;
rc = security_get_permissions(objclass, &perms, &nperms);
if (rc)
goto out;
for (i = 0; i < nperms; i++) {
struct inode *inode;
struct dentry *dentry;
dentry = d_alloc_name(dir, perms[i]);
if (!dentry) {
rc = -ENOMEM;
goto out1;
}
inode = sel_make_inode(dir->d_sb, S_IFREG|S_IRUGO);
if (!inode) {
rc = -ENOMEM;
goto out1;
}
inode->i_fop = &sel_perm_ops;
/* i+1 since perm values are 1-indexed */
inode->i_ino = sel_perm_to_ino(classvalue, i+1);
d_add(dentry, inode);
}
out1:
for (i = 0; i < nperms; i++)
kfree(perms[i]);
kfree(perms);
out:
return rc;
}
static int sel_make_class_dir_entries(char *classname, int index,
struct dentry *dir)
{
struct dentry *dentry = NULL;
struct inode *inode = NULL;
int rc;
dentry = d_alloc_name(dir, "index");
if (!dentry) {
rc = -ENOMEM;
goto out;
}
inode = sel_make_inode(dir->d_sb, S_IFREG|S_IRUGO);
if (!inode) {
rc = -ENOMEM;
goto out;
}
inode->i_fop = &sel_class_ops;
inode->i_ino = sel_class_to_ino(index);
d_add(dentry, inode);
dentry = d_alloc_name(dir, "perms");
if (!dentry) {
rc = -ENOMEM;
goto out;
}
rc = sel_make_dir(dir->d_inode, dentry, &last_class_ino);
if (rc)
goto out;
rc = sel_make_perm_files(classname, index, dentry);
out:
return rc;
}
static void sel_remove_classes(void)
{
struct list_head *class_node;
list_for_each(class_node, &class_dir->d_subdirs) {
struct dentry *class_subdir = list_entry(class_node,
struct dentry, d_u.d_child);
struct list_head *class_subdir_node;
list_for_each(class_subdir_node, &class_subdir->d_subdirs) {
struct dentry *d = list_entry(class_subdir_node,
struct dentry, d_u.d_child);
if (d->d_inode)
if (d->d_inode->i_mode & S_IFDIR)
sel_remove_entries(d);
}
sel_remove_entries(class_subdir);
}
sel_remove_entries(class_dir);
}
static int sel_make_classes(void)
{
int rc = 0, nclasses, i;
char **classes;
/* delete any existing entries */
sel_remove_classes();
rc = security_get_classes(&classes, &nclasses);
if (rc < 0)
goto out;
/* +2 since classes are 1-indexed */
last_class_ino = sel_class_to_ino(nclasses+2);
for (i = 0; i < nclasses; i++) {
struct dentry *class_name_dir;
class_name_dir = d_alloc_name(class_dir, classes[i]);
if (!class_name_dir) {
rc = -ENOMEM;
goto out1;
}
rc = sel_make_dir(class_dir->d_inode, class_name_dir,
&last_class_ino);
if (rc)
goto out1;
/* i+1 since class values are 1-indexed */
rc = sel_make_class_dir_entries(classes[i], i+1,
class_name_dir);
if (rc)
goto out1;
}
out1:
for (i = 0; i < nclasses; i++)
kfree(classes[i]);
kfree(classes);
out:
return rc;
}
static int sel_make_policycap(void)
{
unsigned int iter;
struct dentry *dentry = NULL;
struct inode *inode = NULL;
sel_remove_entries(policycap_dir);
for (iter = 0; iter <= POLICYDB_CAPABILITY_MAX; iter++) {
if (iter < ARRAY_SIZE(policycap_names))
dentry = d_alloc_name(policycap_dir,
policycap_names[iter]);
else
dentry = d_alloc_name(policycap_dir, "unknown");
if (dentry == NULL)
return -ENOMEM;
inode = sel_make_inode(policycap_dir->d_sb, S_IFREG | S_IRUGO);
if (inode == NULL)
return -ENOMEM;
inode->i_fop = &sel_policycap_ops;
inode->i_ino = iter | SEL_POLICYCAP_INO_OFFSET;
d_add(dentry, inode);
}
return 0;
}
static int sel_make_dir(struct inode *dir, struct dentry *dentry,
unsigned long *ino)
{
int ret = 0;
struct inode *inode;
inode = sel_make_inode(dir->i_sb, S_IFDIR | S_IRUGO | S_IXUGO);
if (!inode) {
ret = -ENOMEM;
goto out;
}
inode->i_op = &simple_dir_inode_operations;
inode->i_fop = &simple_dir_operations;
inode->i_ino = ++(*ino);
/* directory inodes start off with i_nlink == 2 (for "." entry) */
inc_nlink(inode);
d_add(dentry, inode);
/* bump link count on parent directory, too */
inc_nlink(dir);
out:
return ret;
}
static int sel_fill_super(struct super_block *sb, void *data, int silent)
{
int ret;
struct dentry *dentry;
struct inode *inode, *root_inode;
struct inode_security_struct *isec;
static struct tree_descr selinux_files[] = {
[SEL_LOAD] = {"load", &sel_load_ops, S_IRUSR|S_IWUSR},
[SEL_ENFORCE] = {"enforce", &sel_enforce_ops, S_IRUGO|S_IWUSR},
[SEL_CONTEXT] = {"context", &transaction_ops, S_IRUGO|S_IWUGO},
[SEL_ACCESS] = {"access", &transaction_ops, S_IRUGO|S_IWUGO},
[SEL_CREATE] = {"create", &transaction_ops, S_IRUGO|S_IWUGO},
[SEL_RELABEL] = {"relabel", &transaction_ops, S_IRUGO|S_IWUGO},
[SEL_USER] = {"user", &transaction_ops, S_IRUGO|S_IWUGO},
[SEL_POLICYVERS] = {"policyvers", &sel_policyvers_ops, S_IRUGO},
[SEL_COMMIT_BOOLS] = {"commit_pending_bools", &sel_commit_bools_ops, S_IWUSR},
[SEL_MLS] = {"mls", &sel_mls_ops, S_IRUGO},
[SEL_DISABLE] = {"disable", &sel_disable_ops, S_IWUSR},
[SEL_MEMBER] = {"member", &transaction_ops, S_IRUGO|S_IWUGO},
[SEL_CHECKREQPROT] = {"checkreqprot", &sel_checkreqprot_ops, S_IRUGO|S_IWUSR},
[SEL_COMPAT_NET] = {"compat_net", &sel_compat_net_ops, S_IRUGO|S_IWUSR},
[SEL_REJECT_UNKNOWN] = {"reject_unknown", &sel_handle_unknown_ops, S_IRUGO},
[SEL_DENY_UNKNOWN] = {"deny_unknown", &sel_handle_unknown_ops, S_IRUGO},
/* last one */ {""}
};
ret = simple_fill_super(sb, SELINUX_MAGIC, selinux_files);
if (ret)
goto err;
root_inode = sb->s_root->d_inode;
dentry = d_alloc_name(sb->s_root, BOOL_DIR_NAME);
if (!dentry) {
ret = -ENOMEM;
goto err;
}
ret = sel_make_dir(root_inode, dentry, &sel_last_ino);
if (ret)
goto err;
bool_dir = dentry;
dentry = d_alloc_name(sb->s_root, NULL_FILE_NAME);
if (!dentry) {
ret = -ENOMEM;
goto err;
}
inode = sel_make_inode(sb, S_IFCHR | S_IRUGO | S_IWUGO);
if (!inode) {
ret = -ENOMEM;
goto err;
}
inode->i_ino = ++sel_last_ino;
isec = (struct inode_security_struct *)inode->i_security;
isec->sid = SECINITSID_DEVNULL;
isec->sclass = SECCLASS_CHR_FILE;
isec->initialized = 1;
init_special_inode(inode, S_IFCHR | S_IRUGO | S_IWUGO, MKDEV(MEM_MAJOR, 3));
d_add(dentry, inode);
selinux_null = dentry;
dentry = d_alloc_name(sb->s_root, "avc");
if (!dentry) {
ret = -ENOMEM;
goto err;
}
ret = sel_make_dir(root_inode, dentry, &sel_last_ino);
if (ret)
goto err;
ret = sel_make_avc_files(dentry);
if (ret)
goto err;
dentry = d_alloc_name(sb->s_root, "initial_contexts");
if (!dentry) {
ret = -ENOMEM;
goto err;
}
ret = sel_make_dir(root_inode, dentry, &sel_last_ino);
if (ret)
goto err;
ret = sel_make_initcon_files(dentry);
if (ret)
goto err;
dentry = d_alloc_name(sb->s_root, "class");
if (!dentry) {
ret = -ENOMEM;
goto err;
}
ret = sel_make_dir(root_inode, dentry, &sel_last_ino);
if (ret)
goto err;
class_dir = dentry;
dentry = d_alloc_name(sb->s_root, "policy_capabilities");
if (!dentry) {
ret = -ENOMEM;
goto err;
}
ret = sel_make_dir(root_inode, dentry, &sel_last_ino);
if (ret)
goto err;
policycap_dir = dentry;
out:
return ret;
err:
printk(KERN_ERR "SELinux: %s: failed while creating inodes\n",
__func__);
goto out;
}
[PATCH] VFS: Permit filesystem to override root dentry on mount Extend the get_sb() filesystem operation to take an extra argument that permits the VFS to pass in the target vfsmount that defines the mountpoint. The filesystem is then required to manually set the superblock and root dentry pointers. For most filesystems, this should be done with simple_set_mnt() which will set the superblock pointer and then set the root dentry to the superblock's s_root (as per the old default behaviour). The get_sb() op now returns an integer as there's now no need to return the superblock pointer. This patch permits a superblock to be implicitly shared amongst several mount points, such as can be done with NFS to avoid potential inode aliasing. In such a case, simple_set_mnt() would not be called, and instead the mnt_root and mnt_sb would be set directly. The patch also makes the following changes: (*) the get_sb_*() convenience functions in the core kernel now take a vfsmount pointer argument and return an integer, so most filesystems have to change very little. (*) If one of the convenience function is not used, then get_sb() should normally call simple_set_mnt() to instantiate the vfsmount. This will always return 0, and so can be tail-called from get_sb(). (*) generic_shutdown_super() now calls shrink_dcache_sb() to clean up the dcache upon superblock destruction rather than shrink_dcache_anon(). This is required because the superblock may now have multiple trees that aren't actually bound to s_root, but that still need to be cleaned up. The currently called functions assume that the whole tree is rooted at s_root, and that anonymous dentries are not the roots of trees which results in dentries being left unculled. However, with the way NFS superblock sharing are currently set to be implemented, these assumptions are violated: the root of the filesystem is simply a dummy dentry and inode (the real inode for '/' may well be inaccessible), and all the vfsmounts are rooted on anonymous[*] dentries with child trees. [*] Anonymous until discovered from another tree. (*) The documentation has been adjusted, including the additional bit of changing ext2_* into foo_* in the documentation. [akpm@osdl.org: convert ipath_fs, do other stuff] Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Al Viro <viro@zeniv.linux.org.uk> Cc: Nathan Scott <nathans@sgi.com> Cc: Roland Dreier <rolandd@cisco.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-23 02:02:57 -07:00
static int sel_get_sb(struct file_system_type *fs_type,
int flags, const char *dev_name, void *data,
struct vfsmount *mnt)
{
[PATCH] VFS: Permit filesystem to override root dentry on mount Extend the get_sb() filesystem operation to take an extra argument that permits the VFS to pass in the target vfsmount that defines the mountpoint. The filesystem is then required to manually set the superblock and root dentry pointers. For most filesystems, this should be done with simple_set_mnt() which will set the superblock pointer and then set the root dentry to the superblock's s_root (as per the old default behaviour). The get_sb() op now returns an integer as there's now no need to return the superblock pointer. This patch permits a superblock to be implicitly shared amongst several mount points, such as can be done with NFS to avoid potential inode aliasing. In such a case, simple_set_mnt() would not be called, and instead the mnt_root and mnt_sb would be set directly. The patch also makes the following changes: (*) the get_sb_*() convenience functions in the core kernel now take a vfsmount pointer argument and return an integer, so most filesystems have to change very little. (*) If one of the convenience function is not used, then get_sb() should normally call simple_set_mnt() to instantiate the vfsmount. This will always return 0, and so can be tail-called from get_sb(). (*) generic_shutdown_super() now calls shrink_dcache_sb() to clean up the dcache upon superblock destruction rather than shrink_dcache_anon(). This is required because the superblock may now have multiple trees that aren't actually bound to s_root, but that still need to be cleaned up. The currently called functions assume that the whole tree is rooted at s_root, and that anonymous dentries are not the roots of trees which results in dentries being left unculled. However, with the way NFS superblock sharing are currently set to be implemented, these assumptions are violated: the root of the filesystem is simply a dummy dentry and inode (the real inode for '/' may well be inaccessible), and all the vfsmounts are rooted on anonymous[*] dentries with child trees. [*] Anonymous until discovered from another tree. (*) The documentation has been adjusted, including the additional bit of changing ext2_* into foo_* in the documentation. [akpm@osdl.org: convert ipath_fs, do other stuff] Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Al Viro <viro@zeniv.linux.org.uk> Cc: Nathan Scott <nathans@sgi.com> Cc: Roland Dreier <rolandd@cisco.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-23 02:02:57 -07:00
return get_sb_single(fs_type, flags, data, sel_fill_super, mnt);
}
static struct file_system_type sel_fs_type = {
.name = "selinuxfs",
.get_sb = sel_get_sb,
.kill_sb = kill_litter_super,
};
struct vfsmount *selinuxfs_mount;
static int __init init_sel_fs(void)
{
int err;
if (!selinux_enabled)
return 0;
err = register_filesystem(&sel_fs_type);
if (!err) {
selinuxfs_mount = kern_mount(&sel_fs_type);
if (IS_ERR(selinuxfs_mount)) {
printk(KERN_ERR "selinuxfs: could not mount!\n");
err = PTR_ERR(selinuxfs_mount);
selinuxfs_mount = NULL;
}
}
return err;
}
__initcall(init_sel_fs);
#ifdef CONFIG_SECURITY_SELINUX_DISABLE
void exit_sel_fs(void)
{
unregister_filesystem(&sel_fs_type);
}
#endif