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selinuxfs.c
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/* Updated: Karl MacMillan <kmacmillan@tresys.com>
*
* Added conditional policy language extensions
*
* Updated: Hewlett-Packard <paul@paul-moore.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>
#include <linux/kobject.h>
#include <linux/ctype.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",
"redhat1",
"always_check_network"
};
unsigned int selinux_checkreqprot = CONFIG_SECURITY_SELINUX_CHECKREQPROT_VALUE;
static int __init checkreqprot_setup(char *str)
{
unsigned long checkreqprot;
if (!kstrtoul(str, 0, &checkreqprot))
selinux_checkreqprot = checkreqprot ? 1 : 0;
return 1;
}
__setup("checkreqprot=", checkreqprot_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;
static char policy_opened;
/* global data for policy capabilities */
static struct dentry *policycap_dir;
/* Check whether a task is allowed to use a security operation. */
static int task_has_security(struct task_struct *tsk,
u32 perms)
{
const struct task_security_struct *tsec;
u32 sid = 0;
rcu_read_lock();
tsec = __task_cred(tsk)->security;
if (tsec)
sid = tsec->sid;
rcu_read_unlock();
if (!tsec)
return -EACCES;
return avc_has_perm(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_STATUS, /* export current status using mmap() */
SEL_POLICY, /* allow userspace to read the in kernel policy */
SEL_VALIDATE_TRANS, /* compute validatetrans decision */
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 = NULL;
ssize_t length;
int new_value;
if (count >= PAGE_SIZE)
return -ENOMEM;
/* No partial writes. */
if (*ppos != 0)
return -EINVAL;
page = memdup_user_nul(buf, count);
if (IS_ERR(page))
return PTR_ERR(page);
length = -EINVAL;
if (sscanf(page, "%d", &new_value) != 1)
goto out;
new_value = !!new_value;
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,
from_kuid(&init_user_ns, audit_get_loginuid(current)),
audit_get_sessionid(current));
selinux_enforcing = new_value;
if (selinux_enforcing)
avc_ss_reset(0);
selnl_notify_setenforce(selinux_enforcing);
selinux_status_update_setenforce(selinux_enforcing);
}
length = count;
out:
kfree(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,
.llseek = generic_file_llseek,
};
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 = file_inode(filp)->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,
.llseek = generic_file_llseek,
};
static int sel_open_handle_status(struct inode *inode, struct file *filp)
{
struct page *status = selinux_kernel_status_page();
if (!status)
return -ENOMEM;
filp->private_data = status;
return 0;
}
static ssize_t sel_read_handle_status(struct file *filp, char __user *buf,
size_t count, loff_t *ppos)
{
struct page *status = filp->private_data;
BUG_ON(!status);
return simple_read_from_buffer(buf, count, ppos,
page_address(status),
sizeof(struct selinux_kernel_status));
}
static int sel_mmap_handle_status(struct file *filp,
struct vm_area_struct *vma)
{
struct page *status = filp->private_data;
unsigned long size = vma->vm_end - vma->vm_start;
BUG_ON(!status);
/* only allows one page from the head */
if (vma->vm_pgoff > 0 || size != PAGE_SIZE)
return -EIO;
/* disallow writable mapping */
if (vma->vm_flags & VM_WRITE)
return -EPERM;
/* disallow mprotect() turns it into writable */
vma->vm_flags &= ~VM_MAYWRITE;
return remap_pfn_range(vma, vma->vm_start,
page_to_pfn(status),
size, vma->vm_page_prot);
}
static const struct file_operations sel_handle_status_ops = {
.open = sel_open_handle_status,
.read = sel_read_handle_status,
.mmap = sel_mmap_handle_status,
.llseek = generic_file_llseek,
};
#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;
if (count >= PAGE_SIZE)
return -ENOMEM;
/* No partial writes. */
if (*ppos != 0)
return -EINVAL;
page = memdup_user_nul(buf, count);
if (IS_ERR(page))
return PTR_ERR(page);
length = -EINVAL;
if (sscanf(page, "%d", &new_value) != 1)
goto out;
if (new_value) {
length = selinux_disable();
if (length)
goto out;
audit_log(current->audit_context, GFP_KERNEL, AUDIT_MAC_STATUS,
"selinux=0 auid=%u ses=%u",
from_kuid(&init_user_ns, audit_get_loginuid(current)),
audit_get_sessionid(current));
}
length = count;
out:
kfree(page);
return length;
}
#else
#define sel_write_disable NULL
#endif
static const struct file_operations sel_disable_ops = {
.write = sel_write_disable,
.llseek = generic_file_llseek,
};
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,
.llseek = generic_file_llseek,
};
/* 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 struct dentry *sel_make_dir(struct dentry *dir, const char *name,
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",
security_mls_enabled());
return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
}
static const struct file_operations sel_mls_ops = {
.read = sel_read_mls,
.llseek = generic_file_llseek,
};
struct policy_load_memory {
size_t len;
void *data;
};
static int sel_open_policy(struct inode *inode, struct file *filp)
{
struct policy_load_memory *plm = NULL;
int rc;
BUG_ON(filp->private_data);
mutex_lock(&sel_mutex);
rc = task_has_security(current, SECURITY__READ_POLICY);
if (rc)
goto err;
rc = -EBUSY;
if (policy_opened)
goto err;
rc = -ENOMEM;
plm = kzalloc(sizeof(*plm), GFP_KERNEL);
if (!plm)
goto err;
if (i_size_read(inode) != security_policydb_len()) {
inode_lock(inode);
i_size_write(inode, security_policydb_len());
inode_unlock(inode);
}
rc = security_read_policy(&plm->data, &plm->len);
if (rc)
goto err;
policy_opened = 1;
filp->private_data = plm;
mutex_unlock(&sel_mutex);
return 0;
err:
mutex_unlock(&sel_mutex);
if (plm)
vfree(plm->data);
kfree(plm);
return rc;
}
static int sel_release_policy(struct inode *inode, struct file *filp)
{
struct policy_load_memory *plm = filp->private_data;
BUG_ON(!plm);
policy_opened = 0;
vfree(plm->data);
kfree(plm);
return 0;
}
static ssize_t sel_read_policy(struct file *filp, char __user *buf,
size_t count, loff_t *ppos)
{
struct policy_load_memory *plm = filp->private_data;
int ret;
mutex_lock(&sel_mutex);
ret = task_has_security(current, SECURITY__READ_POLICY);
if (ret)
goto out;
ret = simple_read_from_buffer(buf, count, ppos, plm->data, plm->len);
out:
mutex_unlock(&sel_mutex);
return ret;
}
static int sel_mmap_policy_fault(struct vm_area_struct *vma,
struct vm_fault *vmf)
{
struct policy_load_memory *plm = vma->vm_file->private_data;
unsigned long offset;
struct page *page;
if (vmf->flags & (FAULT_FLAG_MKWRITE | FAULT_FLAG_WRITE))
return VM_FAULT_SIGBUS;
offset = vmf->pgoff << PAGE_SHIFT;
if (offset >= roundup(plm->len, PAGE_SIZE))
return VM_FAULT_SIGBUS;
page = vmalloc_to_page(plm->data + offset);
get_page(page);
vmf->page = page;
return 0;
}
static const struct vm_operations_struct sel_mmap_policy_ops = {
.fault = sel_mmap_policy_fault,
.page_mkwrite = sel_mmap_policy_fault,
};
static int sel_mmap_policy(struct file *filp, struct vm_area_struct *vma)
{
if (vma->vm_flags & VM_SHARED) {
/* do not allow mprotect to make mapping writable */
vma->vm_flags &= ~VM_MAYWRITE;
if (vma->vm_flags & VM_WRITE)
return -EACCES;
}
vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP;
vma->vm_ops = &sel_mmap_policy_ops;
return 0;
}
static const struct file_operations sel_policy_ops = {
.open = sel_open_policy,
.read = sel_read_policy,
.mmap = sel_mmap_policy,
.release = sel_release_policy,
.llseek = generic_file_llseek,
};
static ssize_t sel_write_load(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
ssize_t length;
void *data = NULL;
mutex_lock(&sel_mutex);
length = task_has_security(current, SECURITY__LOAD_POLICY);
if (length)
goto out;
/* No partial writes. */
length = -EINVAL;
if (*ppos != 0)
goto out;
length = -EFBIG;
if (count > 64 * 1024 * 1024)
goto out;
length = -ENOMEM;
data = vmalloc(count);
if (!data)
goto out;
length = -EFAULT;
if (copy_from_user(data, buf, count) != 0)
goto out;
length = security_load_policy(data, count);
if (length)
goto out;
length = sel_make_bools();
if (length)
goto out1;
length = sel_make_classes();
if (length)
goto out1;
length = sel_make_policycap();
if (length)
goto out1;
length = count;
out1:
audit_log(current->audit_context, GFP_KERNEL, AUDIT_MAC_POLICY_LOAD,
"policy loaded auid=%u ses=%u",
from_kuid(&init_user_ns, 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,
.llseek = generic_file_llseek,
};
static ssize_t sel_write_context(struct file *file, char *buf, size_t size)
{
char *canon = NULL;
u32 sid, len;
ssize_t length;
length = task_has_security(current, SECURITY__CHECK_CONTEXT);
if (length)
goto out;
length = security_context_to_sid(buf, size, &sid, GFP_KERNEL);
if (length)
goto out;
length = security_sid_to_context(sid, &canon, &len);
if (length)
goto out;
length = -ERANGE;
if (len > SIMPLE_TRANSACTION_LIMIT) {
printk(KERN_ERR "SELinux: %s: context size (%u) exceeds "
"payload max\n", __func__, len);
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;
/* No partial writes. */
if (*ppos != 0)
return -EINVAL;
page = memdup_user_nul(buf, count);
if (IS_ERR(page))
return PTR_ERR(page);
length = -EINVAL;
if (sscanf(page, "%u", &new_value) != 1)
goto out;
selinux_checkreqprot = new_value ? 1 : 0;
length = count;
out:
kfree(page);
return length;
}
static const struct file_operations sel_checkreqprot_ops = {
.read = sel_read_checkreqprot,
.write = sel_write_checkreqprot,
.llseek = generic_file_llseek,
};
static ssize_t sel_write_validatetrans(struct file *file,
const char __user *buf,
size_t count, loff_t *ppos)
{
char *oldcon = NULL, *newcon = NULL, *taskcon = NULL;
char *req = NULL;
u32 osid, nsid, tsid;
u16 tclass;
int rc;
rc = task_has_security(current, SECURITY__VALIDATE_TRANS);
if (rc)
goto out;
rc = -ENOMEM;
if (count >= PAGE_SIZE)
goto out;
/* No partial writes. */
rc = -EINVAL;
if (*ppos != 0)
goto out;
rc = -ENOMEM;
req = kzalloc(count + 1, GFP_KERNEL);
if (!req)
goto out;
rc = -EFAULT;
if (copy_from_user(req, buf, count))
goto out;
rc = -ENOMEM;
oldcon = kzalloc(count + 1, GFP_KERNEL);
if (!oldcon)
goto out;
newcon = kzalloc(count + 1, GFP_KERNEL);
if (!newcon)
goto out;
taskcon = kzalloc(count + 1, GFP_KERNEL);
if (!taskcon)
goto out;
rc = -EINVAL;
if (sscanf(req, "%s %s %hu %s", oldcon, newcon, &tclass, taskcon) != 4)
goto out;
rc = security_context_str_to_sid(oldcon, &osid, GFP_KERNEL);
if (rc)
goto out;
rc = security_context_str_to_sid(newcon, &nsid, GFP_KERNEL);
if (rc)
goto out;
rc = security_context_str_to_sid(taskcon, &tsid, GFP_KERNEL);
if (rc)
goto out;
rc = security_validate_transition_user(osid, nsid, tsid, tclass);
if (!rc)
rc = count;
out:
kfree(req);
kfree(oldcon);
kfree(newcon);
kfree(taskcon);
return rc;
}
static const struct file_operations sel_transition_ops = {
.write = sel_write_validatetrans,
.llseek = generic_file_llseek,
};
/*
* 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_inode(file)->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,
.llseek = generic_file_llseek,
};
/*
* 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 = NULL, *tcon = NULL;
u32 ssid, tsid;
u16 tclass;
struct av_decision avd;
ssize_t length;
length = task_has_security(current, SECURITY__COMPUTE_AV);
if (length)
goto out;
length = -ENOMEM;
scon = kzalloc(size + 1, GFP_KERNEL);
if (!scon)
goto out;
length = -ENOMEM;
tcon = kzalloc(size + 1, GFP_KERNEL);
if (!tcon)
goto out;
length = -EINVAL;
if (sscanf(buf, "%s %s %hu", scon, tcon, &tclass) != 3)
goto out;
length = security_context_str_to_sid(scon, &ssid, GFP_KERNEL);
if (length)
goto out;
length = security_context_str_to_sid(tcon, &tsid, GFP_KERNEL);
if (length)
goto out;
security_compute_av_user(ssid, tsid, tclass, &avd);
length = scnprintf(buf, SIMPLE_TRANSACTION_LIMIT,
"%x %x %x %x %u %x",
avd.allowed, 0xffffffff,
avd.auditallow, avd.auditdeny,
avd.seqno, avd.flags);
out:
kfree(tcon);
kfree(scon);
return length;
}
static ssize_t sel_write_create(struct file *file, char *buf, size_t size)
{
char *scon = NULL, *tcon = NULL;
char *namebuf = NULL, *objname = NULL;
u32 ssid, tsid, newsid;
u16 tclass;
ssize_t length;
char *newcon = NULL;
u32 len;
int nargs;
length = task_has_security(current, SECURITY__COMPUTE_CREATE);
if (length)
goto out;
length = -ENOMEM;
scon = kzalloc(size + 1, GFP_KERNEL);
if (!scon)
goto out;
length = -ENOMEM;
tcon = kzalloc(size + 1, GFP_KERNEL);
if (!tcon)
goto out;
length = -ENOMEM;
namebuf = kzalloc(size + 1, GFP_KERNEL);
if (!namebuf)
goto out;
length = -EINVAL;
nargs = sscanf(buf, "%s %s %hu %s", scon, tcon, &tclass, namebuf);
if (nargs < 3 || nargs > 4)
goto out;
if (nargs == 4) {
/*
* If and when the name of new object to be queried contains
* either whitespace or multibyte characters, they shall be
* encoded based on the percentage-encoding rule.
* If not encoded, the sscanf logic picks up only left-half
* of the supplied name; splitted by a whitespace unexpectedly.
*/
char *r, *w;
int c1, c2;
r = w = namebuf;
do {
c1 = *r++;
if (c1 == '+')
c1 = ' ';
else if (c1 == '%') {
c1 = hex_to_bin(*r++);
if (c1 < 0)
goto out;
c2 = hex_to_bin(*r++);
if (c2 < 0)
goto out;
c1 = (c1 << 4) | c2;
}
*w++ = c1;
} while (c1 != '\0');
objname = namebuf;
}
length = security_context_str_to_sid(scon, &ssid, GFP_KERNEL);
if (length)
goto out;
length = security_context_str_to_sid(tcon, &tsid, GFP_KERNEL);
if (length)
goto out;
length = security_transition_sid_user(ssid, tsid, tclass,
objname, &newsid);
if (length)
goto out;
length = security_sid_to_context(newsid, &newcon, &len);
if (length)
goto out;
length = -ERANGE;
if (len > SIMPLE_TRANSACTION_LIMIT) {
printk(KERN_ERR "SELinux: %s: context size (%u) exceeds "
"payload max\n", __func__, len);
goto out;
}
memcpy(buf, newcon, len);
length = len;
out:
kfree(newcon);
kfree(namebuf);
kfree(tcon);
kfree(scon);
return length;
}
static ssize_t sel_write_relabel(struct file *file, char *buf, size_t size)
{
char *scon = NULL, *tcon = NULL;
u32 ssid, tsid, newsid;
u16 tclass;
ssize_t length;
char *newcon = NULL;
u32 len;
length = task_has_security(current, SECURITY__COMPUTE_RELABEL);
if (length)
goto out;
length = -ENOMEM;
scon = kzalloc(size + 1, GFP_KERNEL);
if (!scon)
goto out;
length = -ENOMEM;
tcon = kzalloc(size + 1, GFP_KERNEL);
if (!tcon)
goto out;
length = -EINVAL;
if (sscanf(buf, "%s %s %hu", scon, tcon, &tclass) != 3)
goto out;
length = security_context_str_to_sid(scon, &ssid, GFP_KERNEL);
if (length)
goto out;
length = security_context_str_to_sid(tcon, &tsid, GFP_KERNEL);
if (length)
goto out;
length = security_change_sid(ssid, tsid, tclass, &newsid);
if (length)
goto out;
length = security_sid_to_context(newsid, &newcon, &len);
if (length)
goto out;
length = -ERANGE;
if (len > SIMPLE_TRANSACTION_LIMIT)
goto out;
memcpy(buf, newcon, len);
length = len;
out:
kfree(newcon);
kfree(tcon);
kfree(scon);
return length;
}
static ssize_t sel_write_user(struct file *file, char *buf, size_t size)
{
char *con = NULL, *user = NULL, *ptr;
u32 sid, *sids = NULL;
ssize_t length;
char *newcon;
int i, rc;
u32 len, nsids;
length = task_has_security(current, SECURITY__COMPUTE_USER);
if (length)
goto out;
length = -ENOMEM;
con = kzalloc(size + 1, GFP_KERNEL);
if (!con)
goto out;
length = -ENOMEM;
user = kzalloc(size + 1, GFP_KERNEL);
if (!user)
goto out;
length = -EINVAL;
if (sscanf(buf, "%s %s", con, user) != 2)
goto out;
length = security_context_str_to_sid(con, &sid, GFP_KERNEL);
if (length)
goto out;
length = security_get_user_sids(sid, user, &sids, &nsids);