mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-12-05 10:04:12 +08:00
c7b87de23b
When an EVM protected extended attribute is removed, update 'security.evm'. Signed-off-by: Mimi Zohar <zohar@us.ibm.com> Acked-by: Serge Hallyn <serge.hallyn@ubuntu.com>
760 lines
17 KiB
C
760 lines
17 KiB
C
/*
|
|
File: fs/xattr.c
|
|
|
|
Extended attribute handling.
|
|
|
|
Copyright (C) 2001 by Andreas Gruenbacher <a.gruenbacher@computer.org>
|
|
Copyright (C) 2001 SGI - Silicon Graphics, Inc <linux-xfs@oss.sgi.com>
|
|
Copyright (c) 2004 Red Hat, Inc., James Morris <jmorris@redhat.com>
|
|
*/
|
|
#include <linux/fs.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/file.h>
|
|
#include <linux/xattr.h>
|
|
#include <linux/mount.h>
|
|
#include <linux/namei.h>
|
|
#include <linux/security.h>
|
|
#include <linux/evm.h>
|
|
#include <linux/syscalls.h>
|
|
#include <linux/module.h>
|
|
#include <linux/fsnotify.h>
|
|
#include <linux/audit.h>
|
|
#include <asm/uaccess.h>
|
|
|
|
|
|
/*
|
|
* Check permissions for extended attribute access. This is a bit complicated
|
|
* because different namespaces have very different rules.
|
|
*/
|
|
static int
|
|
xattr_permission(struct inode *inode, const char *name, int mask)
|
|
{
|
|
/*
|
|
* We can never set or remove an extended attribute on a read-only
|
|
* filesystem or on an immutable / append-only inode.
|
|
*/
|
|
if (mask & MAY_WRITE) {
|
|
if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
|
|
return -EPERM;
|
|
}
|
|
|
|
/*
|
|
* No restriction for security.* and system.* from the VFS. Decision
|
|
* on these is left to the underlying filesystem / security module.
|
|
*/
|
|
if (!strncmp(name, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN) ||
|
|
!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
|
|
return 0;
|
|
|
|
/*
|
|
* The trusted.* namespace can only be accessed by privileged users.
|
|
*/
|
|
if (!strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN)) {
|
|
if (!capable(CAP_SYS_ADMIN))
|
|
return (mask & MAY_WRITE) ? -EPERM : -ENODATA;
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* In the user.* namespace, only regular files and directories can have
|
|
* extended attributes. For sticky directories, only the owner and
|
|
* privileged users can write attributes.
|
|
*/
|
|
if (!strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN)) {
|
|
if (!S_ISREG(inode->i_mode) && !S_ISDIR(inode->i_mode))
|
|
return (mask & MAY_WRITE) ? -EPERM : -ENODATA;
|
|
if (S_ISDIR(inode->i_mode) && (inode->i_mode & S_ISVTX) &&
|
|
(mask & MAY_WRITE) && !inode_owner_or_capable(inode))
|
|
return -EPERM;
|
|
}
|
|
|
|
return inode_permission(inode, mask);
|
|
}
|
|
|
|
/**
|
|
* __vfs_setxattr_noperm - perform setxattr operation without performing
|
|
* permission checks.
|
|
*
|
|
* @dentry - object to perform setxattr on
|
|
* @name - xattr name to set
|
|
* @value - value to set @name to
|
|
* @size - size of @value
|
|
* @flags - flags to pass into filesystem operations
|
|
*
|
|
* returns the result of the internal setxattr or setsecurity operations.
|
|
*
|
|
* This function requires the caller to lock the inode's i_mutex before it
|
|
* is executed. It also assumes that the caller will make the appropriate
|
|
* permission checks.
|
|
*/
|
|
int __vfs_setxattr_noperm(struct dentry *dentry, const char *name,
|
|
const void *value, size_t size, int flags)
|
|
{
|
|
struct inode *inode = dentry->d_inode;
|
|
int error = -EOPNOTSUPP;
|
|
int issec = !strncmp(name, XATTR_SECURITY_PREFIX,
|
|
XATTR_SECURITY_PREFIX_LEN);
|
|
|
|
if (issec)
|
|
inode->i_flags &= ~S_NOSEC;
|
|
if (inode->i_op->setxattr) {
|
|
error = inode->i_op->setxattr(dentry, name, value, size, flags);
|
|
if (!error) {
|
|
fsnotify_xattr(dentry);
|
|
security_inode_post_setxattr(dentry, name, value,
|
|
size, flags);
|
|
}
|
|
} else if (issec) {
|
|
const char *suffix = name + XATTR_SECURITY_PREFIX_LEN;
|
|
error = security_inode_setsecurity(inode, suffix, value,
|
|
size, flags);
|
|
if (!error)
|
|
fsnotify_xattr(dentry);
|
|
}
|
|
|
|
return error;
|
|
}
|
|
|
|
|
|
int
|
|
vfs_setxattr(struct dentry *dentry, const char *name, const void *value,
|
|
size_t size, int flags)
|
|
{
|
|
struct inode *inode = dentry->d_inode;
|
|
int error;
|
|
|
|
error = xattr_permission(inode, name, MAY_WRITE);
|
|
if (error)
|
|
return error;
|
|
|
|
mutex_lock(&inode->i_mutex);
|
|
error = security_inode_setxattr(dentry, name, value, size, flags);
|
|
if (error)
|
|
goto out;
|
|
|
|
error = __vfs_setxattr_noperm(dentry, name, value, size, flags);
|
|
|
|
out:
|
|
mutex_unlock(&inode->i_mutex);
|
|
return error;
|
|
}
|
|
EXPORT_SYMBOL_GPL(vfs_setxattr);
|
|
|
|
ssize_t
|
|
xattr_getsecurity(struct inode *inode, const char *name, void *value,
|
|
size_t size)
|
|
{
|
|
void *buffer = NULL;
|
|
ssize_t len;
|
|
|
|
if (!value || !size) {
|
|
len = security_inode_getsecurity(inode, name, &buffer, false);
|
|
goto out_noalloc;
|
|
}
|
|
|
|
len = security_inode_getsecurity(inode, name, &buffer, true);
|
|
if (len < 0)
|
|
return len;
|
|
if (size < len) {
|
|
len = -ERANGE;
|
|
goto out;
|
|
}
|
|
memcpy(value, buffer, len);
|
|
out:
|
|
security_release_secctx(buffer, len);
|
|
out_noalloc:
|
|
return len;
|
|
}
|
|
EXPORT_SYMBOL_GPL(xattr_getsecurity);
|
|
|
|
/*
|
|
* vfs_getxattr_alloc - allocate memory, if necessary, before calling getxattr
|
|
*
|
|
* Allocate memory, if not already allocated, or re-allocate correct size,
|
|
* before retrieving the extended attribute.
|
|
*
|
|
* Returns the result of alloc, if failed, or the getxattr operation.
|
|
*/
|
|
ssize_t
|
|
vfs_getxattr_alloc(struct dentry *dentry, const char *name, char **xattr_value,
|
|
size_t xattr_size, gfp_t flags)
|
|
{
|
|
struct inode *inode = dentry->d_inode;
|
|
char *value = *xattr_value;
|
|
int error;
|
|
|
|
error = xattr_permission(inode, name, MAY_READ);
|
|
if (error)
|
|
return error;
|
|
|
|
if (!inode->i_op->getxattr)
|
|
return -EOPNOTSUPP;
|
|
|
|
error = inode->i_op->getxattr(dentry, name, NULL, 0);
|
|
if (error < 0)
|
|
return error;
|
|
|
|
if (!value || (error > xattr_size)) {
|
|
value = krealloc(*xattr_value, error + 1, flags);
|
|
if (!value)
|
|
return -ENOMEM;
|
|
memset(value, 0, error + 1);
|
|
}
|
|
|
|
error = inode->i_op->getxattr(dentry, name, value, error);
|
|
*xattr_value = value;
|
|
return error;
|
|
}
|
|
|
|
/* Compare an extended attribute value with the given value */
|
|
int vfs_xattr_cmp(struct dentry *dentry, const char *xattr_name,
|
|
const char *value, size_t size, gfp_t flags)
|
|
{
|
|
char *xattr_value = NULL;
|
|
int rc;
|
|
|
|
rc = vfs_getxattr_alloc(dentry, xattr_name, &xattr_value, 0, flags);
|
|
if (rc < 0)
|
|
return rc;
|
|
|
|
if ((rc != size) || (memcmp(xattr_value, value, rc) != 0))
|
|
rc = -EINVAL;
|
|
else
|
|
rc = 0;
|
|
kfree(xattr_value);
|
|
return rc;
|
|
}
|
|
|
|
ssize_t
|
|
vfs_getxattr(struct dentry *dentry, const char *name, void *value, size_t size)
|
|
{
|
|
struct inode *inode = dentry->d_inode;
|
|
int error;
|
|
|
|
error = xattr_permission(inode, name, MAY_READ);
|
|
if (error)
|
|
return error;
|
|
|
|
error = security_inode_getxattr(dentry, name);
|
|
if (error)
|
|
return error;
|
|
|
|
if (!strncmp(name, XATTR_SECURITY_PREFIX,
|
|
XATTR_SECURITY_PREFIX_LEN)) {
|
|
const char *suffix = name + XATTR_SECURITY_PREFIX_LEN;
|
|
int ret = xattr_getsecurity(inode, suffix, value, size);
|
|
/*
|
|
* Only overwrite the return value if a security module
|
|
* is actually active.
|
|
*/
|
|
if (ret == -EOPNOTSUPP)
|
|
goto nolsm;
|
|
return ret;
|
|
}
|
|
nolsm:
|
|
if (inode->i_op->getxattr)
|
|
error = inode->i_op->getxattr(dentry, name, value, size);
|
|
else
|
|
error = -EOPNOTSUPP;
|
|
|
|
return error;
|
|
}
|
|
EXPORT_SYMBOL_GPL(vfs_getxattr);
|
|
|
|
ssize_t
|
|
vfs_listxattr(struct dentry *d, char *list, size_t size)
|
|
{
|
|
ssize_t error;
|
|
|
|
error = security_inode_listxattr(d);
|
|
if (error)
|
|
return error;
|
|
error = -EOPNOTSUPP;
|
|
if (d->d_inode->i_op->listxattr) {
|
|
error = d->d_inode->i_op->listxattr(d, list, size);
|
|
} else {
|
|
error = security_inode_listsecurity(d->d_inode, list, size);
|
|
if (size && error > size)
|
|
error = -ERANGE;
|
|
}
|
|
return error;
|
|
}
|
|
EXPORT_SYMBOL_GPL(vfs_listxattr);
|
|
|
|
int
|
|
vfs_removexattr(struct dentry *dentry, const char *name)
|
|
{
|
|
struct inode *inode = dentry->d_inode;
|
|
int error;
|
|
|
|
if (!inode->i_op->removexattr)
|
|
return -EOPNOTSUPP;
|
|
|
|
error = xattr_permission(inode, name, MAY_WRITE);
|
|
if (error)
|
|
return error;
|
|
|
|
error = security_inode_removexattr(dentry, name);
|
|
if (error)
|
|
return error;
|
|
|
|
mutex_lock(&inode->i_mutex);
|
|
error = inode->i_op->removexattr(dentry, name);
|
|
mutex_unlock(&inode->i_mutex);
|
|
|
|
if (!error) {
|
|
fsnotify_xattr(dentry);
|
|
evm_inode_post_removexattr(dentry, name);
|
|
}
|
|
return error;
|
|
}
|
|
EXPORT_SYMBOL_GPL(vfs_removexattr);
|
|
|
|
|
|
/*
|
|
* Extended attribute SET operations
|
|
*/
|
|
static long
|
|
setxattr(struct dentry *d, const char __user *name, const void __user *value,
|
|
size_t size, int flags)
|
|
{
|
|
int error;
|
|
void *kvalue = NULL;
|
|
char kname[XATTR_NAME_MAX + 1];
|
|
|
|
if (flags & ~(XATTR_CREATE|XATTR_REPLACE))
|
|
return -EINVAL;
|
|
|
|
error = strncpy_from_user(kname, name, sizeof(kname));
|
|
if (error == 0 || error == sizeof(kname))
|
|
error = -ERANGE;
|
|
if (error < 0)
|
|
return error;
|
|
|
|
if (size) {
|
|
if (size > XATTR_SIZE_MAX)
|
|
return -E2BIG;
|
|
kvalue = memdup_user(value, size);
|
|
if (IS_ERR(kvalue))
|
|
return PTR_ERR(kvalue);
|
|
}
|
|
|
|
error = vfs_setxattr(d, kname, kvalue, size, flags);
|
|
kfree(kvalue);
|
|
return error;
|
|
}
|
|
|
|
SYSCALL_DEFINE5(setxattr, const char __user *, pathname,
|
|
const char __user *, name, const void __user *, value,
|
|
size_t, size, int, flags)
|
|
{
|
|
struct path path;
|
|
int error;
|
|
|
|
error = user_path(pathname, &path);
|
|
if (error)
|
|
return error;
|
|
error = mnt_want_write(path.mnt);
|
|
if (!error) {
|
|
error = setxattr(path.dentry, name, value, size, flags);
|
|
mnt_drop_write(path.mnt);
|
|
}
|
|
path_put(&path);
|
|
return error;
|
|
}
|
|
|
|
SYSCALL_DEFINE5(lsetxattr, const char __user *, pathname,
|
|
const char __user *, name, const void __user *, value,
|
|
size_t, size, int, flags)
|
|
{
|
|
struct path path;
|
|
int error;
|
|
|
|
error = user_lpath(pathname, &path);
|
|
if (error)
|
|
return error;
|
|
error = mnt_want_write(path.mnt);
|
|
if (!error) {
|
|
error = setxattr(path.dentry, name, value, size, flags);
|
|
mnt_drop_write(path.mnt);
|
|
}
|
|
path_put(&path);
|
|
return error;
|
|
}
|
|
|
|
SYSCALL_DEFINE5(fsetxattr, int, fd, const char __user *, name,
|
|
const void __user *,value, size_t, size, int, flags)
|
|
{
|
|
struct file *f;
|
|
struct dentry *dentry;
|
|
int error = -EBADF;
|
|
|
|
f = fget(fd);
|
|
if (!f)
|
|
return error;
|
|
dentry = f->f_path.dentry;
|
|
audit_inode(NULL, dentry);
|
|
error = mnt_want_write_file(f);
|
|
if (!error) {
|
|
error = setxattr(dentry, name, value, size, flags);
|
|
mnt_drop_write(f->f_path.mnt);
|
|
}
|
|
fput(f);
|
|
return error;
|
|
}
|
|
|
|
/*
|
|
* Extended attribute GET operations
|
|
*/
|
|
static ssize_t
|
|
getxattr(struct dentry *d, const char __user *name, void __user *value,
|
|
size_t size)
|
|
{
|
|
ssize_t error;
|
|
void *kvalue = NULL;
|
|
char kname[XATTR_NAME_MAX + 1];
|
|
|
|
error = strncpy_from_user(kname, name, sizeof(kname));
|
|
if (error == 0 || error == sizeof(kname))
|
|
error = -ERANGE;
|
|
if (error < 0)
|
|
return error;
|
|
|
|
if (size) {
|
|
if (size > XATTR_SIZE_MAX)
|
|
size = XATTR_SIZE_MAX;
|
|
kvalue = kzalloc(size, GFP_KERNEL);
|
|
if (!kvalue)
|
|
return -ENOMEM;
|
|
}
|
|
|
|
error = vfs_getxattr(d, kname, kvalue, size);
|
|
if (error > 0) {
|
|
if (size && copy_to_user(value, kvalue, error))
|
|
error = -EFAULT;
|
|
} else if (error == -ERANGE && size >= XATTR_SIZE_MAX) {
|
|
/* The file system tried to returned a value bigger
|
|
than XATTR_SIZE_MAX bytes. Not possible. */
|
|
error = -E2BIG;
|
|
}
|
|
kfree(kvalue);
|
|
return error;
|
|
}
|
|
|
|
SYSCALL_DEFINE4(getxattr, const char __user *, pathname,
|
|
const char __user *, name, void __user *, value, size_t, size)
|
|
{
|
|
struct path path;
|
|
ssize_t error;
|
|
|
|
error = user_path(pathname, &path);
|
|
if (error)
|
|
return error;
|
|
error = getxattr(path.dentry, name, value, size);
|
|
path_put(&path);
|
|
return error;
|
|
}
|
|
|
|
SYSCALL_DEFINE4(lgetxattr, const char __user *, pathname,
|
|
const char __user *, name, void __user *, value, size_t, size)
|
|
{
|
|
struct path path;
|
|
ssize_t error;
|
|
|
|
error = user_lpath(pathname, &path);
|
|
if (error)
|
|
return error;
|
|
error = getxattr(path.dentry, name, value, size);
|
|
path_put(&path);
|
|
return error;
|
|
}
|
|
|
|
SYSCALL_DEFINE4(fgetxattr, int, fd, const char __user *, name,
|
|
void __user *, value, size_t, size)
|
|
{
|
|
struct file *f;
|
|
ssize_t error = -EBADF;
|
|
|
|
f = fget(fd);
|
|
if (!f)
|
|
return error;
|
|
audit_inode(NULL, f->f_path.dentry);
|
|
error = getxattr(f->f_path.dentry, name, value, size);
|
|
fput(f);
|
|
return error;
|
|
}
|
|
|
|
/*
|
|
* Extended attribute LIST operations
|
|
*/
|
|
static ssize_t
|
|
listxattr(struct dentry *d, char __user *list, size_t size)
|
|
{
|
|
ssize_t error;
|
|
char *klist = NULL;
|
|
|
|
if (size) {
|
|
if (size > XATTR_LIST_MAX)
|
|
size = XATTR_LIST_MAX;
|
|
klist = kmalloc(size, GFP_KERNEL);
|
|
if (!klist)
|
|
return -ENOMEM;
|
|
}
|
|
|
|
error = vfs_listxattr(d, klist, size);
|
|
if (error > 0) {
|
|
if (size && copy_to_user(list, klist, error))
|
|
error = -EFAULT;
|
|
} else if (error == -ERANGE && size >= XATTR_LIST_MAX) {
|
|
/* The file system tried to returned a list bigger
|
|
than XATTR_LIST_MAX bytes. Not possible. */
|
|
error = -E2BIG;
|
|
}
|
|
kfree(klist);
|
|
return error;
|
|
}
|
|
|
|
SYSCALL_DEFINE3(listxattr, const char __user *, pathname, char __user *, list,
|
|
size_t, size)
|
|
{
|
|
struct path path;
|
|
ssize_t error;
|
|
|
|
error = user_path(pathname, &path);
|
|
if (error)
|
|
return error;
|
|
error = listxattr(path.dentry, list, size);
|
|
path_put(&path);
|
|
return error;
|
|
}
|
|
|
|
SYSCALL_DEFINE3(llistxattr, const char __user *, pathname, char __user *, list,
|
|
size_t, size)
|
|
{
|
|
struct path path;
|
|
ssize_t error;
|
|
|
|
error = user_lpath(pathname, &path);
|
|
if (error)
|
|
return error;
|
|
error = listxattr(path.dentry, list, size);
|
|
path_put(&path);
|
|
return error;
|
|
}
|
|
|
|
SYSCALL_DEFINE3(flistxattr, int, fd, char __user *, list, size_t, size)
|
|
{
|
|
struct file *f;
|
|
ssize_t error = -EBADF;
|
|
|
|
f = fget(fd);
|
|
if (!f)
|
|
return error;
|
|
audit_inode(NULL, f->f_path.dentry);
|
|
error = listxattr(f->f_path.dentry, list, size);
|
|
fput(f);
|
|
return error;
|
|
}
|
|
|
|
/*
|
|
* Extended attribute REMOVE operations
|
|
*/
|
|
static long
|
|
removexattr(struct dentry *d, const char __user *name)
|
|
{
|
|
int error;
|
|
char kname[XATTR_NAME_MAX + 1];
|
|
|
|
error = strncpy_from_user(kname, name, sizeof(kname));
|
|
if (error == 0 || error == sizeof(kname))
|
|
error = -ERANGE;
|
|
if (error < 0)
|
|
return error;
|
|
|
|
return vfs_removexattr(d, kname);
|
|
}
|
|
|
|
SYSCALL_DEFINE2(removexattr, const char __user *, pathname,
|
|
const char __user *, name)
|
|
{
|
|
struct path path;
|
|
int error;
|
|
|
|
error = user_path(pathname, &path);
|
|
if (error)
|
|
return error;
|
|
error = mnt_want_write(path.mnt);
|
|
if (!error) {
|
|
error = removexattr(path.dentry, name);
|
|
mnt_drop_write(path.mnt);
|
|
}
|
|
path_put(&path);
|
|
return error;
|
|
}
|
|
|
|
SYSCALL_DEFINE2(lremovexattr, const char __user *, pathname,
|
|
const char __user *, name)
|
|
{
|
|
struct path path;
|
|
int error;
|
|
|
|
error = user_lpath(pathname, &path);
|
|
if (error)
|
|
return error;
|
|
error = mnt_want_write(path.mnt);
|
|
if (!error) {
|
|
error = removexattr(path.dentry, name);
|
|
mnt_drop_write(path.mnt);
|
|
}
|
|
path_put(&path);
|
|
return error;
|
|
}
|
|
|
|
SYSCALL_DEFINE2(fremovexattr, int, fd, const char __user *, name)
|
|
{
|
|
struct file *f;
|
|
struct dentry *dentry;
|
|
int error = -EBADF;
|
|
|
|
f = fget(fd);
|
|
if (!f)
|
|
return error;
|
|
dentry = f->f_path.dentry;
|
|
audit_inode(NULL, dentry);
|
|
error = mnt_want_write_file(f);
|
|
if (!error) {
|
|
error = removexattr(dentry, name);
|
|
mnt_drop_write(f->f_path.mnt);
|
|
}
|
|
fput(f);
|
|
return error;
|
|
}
|
|
|
|
|
|
static const char *
|
|
strcmp_prefix(const char *a, const char *a_prefix)
|
|
{
|
|
while (*a_prefix && *a == *a_prefix) {
|
|
a++;
|
|
a_prefix++;
|
|
}
|
|
return *a_prefix ? NULL : a;
|
|
}
|
|
|
|
/*
|
|
* In order to implement different sets of xattr operations for each xattr
|
|
* prefix with the generic xattr API, a filesystem should create a
|
|
* null-terminated array of struct xattr_handler (one for each prefix) and
|
|
* hang a pointer to it off of the s_xattr field of the superblock.
|
|
*
|
|
* The generic_fooxattr() functions will use this list to dispatch xattr
|
|
* operations to the correct xattr_handler.
|
|
*/
|
|
#define for_each_xattr_handler(handlers, handler) \
|
|
for ((handler) = *(handlers)++; \
|
|
(handler) != NULL; \
|
|
(handler) = *(handlers)++)
|
|
|
|
/*
|
|
* Find the xattr_handler with the matching prefix.
|
|
*/
|
|
static const struct xattr_handler *
|
|
xattr_resolve_name(const struct xattr_handler **handlers, const char **name)
|
|
{
|
|
const struct xattr_handler *handler;
|
|
|
|
if (!*name)
|
|
return NULL;
|
|
|
|
for_each_xattr_handler(handlers, handler) {
|
|
const char *n = strcmp_prefix(*name, handler->prefix);
|
|
if (n) {
|
|
*name = n;
|
|
break;
|
|
}
|
|
}
|
|
return handler;
|
|
}
|
|
|
|
/*
|
|
* Find the handler for the prefix and dispatch its get() operation.
|
|
*/
|
|
ssize_t
|
|
generic_getxattr(struct dentry *dentry, const char *name, void *buffer, size_t size)
|
|
{
|
|
const struct xattr_handler *handler;
|
|
|
|
handler = xattr_resolve_name(dentry->d_sb->s_xattr, &name);
|
|
if (!handler)
|
|
return -EOPNOTSUPP;
|
|
return handler->get(dentry, name, buffer, size, handler->flags);
|
|
}
|
|
|
|
/*
|
|
* Combine the results of the list() operation from every xattr_handler in the
|
|
* list.
|
|
*/
|
|
ssize_t
|
|
generic_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size)
|
|
{
|
|
const struct xattr_handler *handler, **handlers = dentry->d_sb->s_xattr;
|
|
unsigned int size = 0;
|
|
|
|
if (!buffer) {
|
|
for_each_xattr_handler(handlers, handler) {
|
|
size += handler->list(dentry, NULL, 0, NULL, 0,
|
|
handler->flags);
|
|
}
|
|
} else {
|
|
char *buf = buffer;
|
|
|
|
for_each_xattr_handler(handlers, handler) {
|
|
size = handler->list(dentry, buf, buffer_size,
|
|
NULL, 0, handler->flags);
|
|
if (size > buffer_size)
|
|
return -ERANGE;
|
|
buf += size;
|
|
buffer_size -= size;
|
|
}
|
|
size = buf - buffer;
|
|
}
|
|
return size;
|
|
}
|
|
|
|
/*
|
|
* Find the handler for the prefix and dispatch its set() operation.
|
|
*/
|
|
int
|
|
generic_setxattr(struct dentry *dentry, const char *name, const void *value, size_t size, int flags)
|
|
{
|
|
const struct xattr_handler *handler;
|
|
|
|
if (size == 0)
|
|
value = ""; /* empty EA, do not remove */
|
|
handler = xattr_resolve_name(dentry->d_sb->s_xattr, &name);
|
|
if (!handler)
|
|
return -EOPNOTSUPP;
|
|
return handler->set(dentry, name, value, size, flags, handler->flags);
|
|
}
|
|
|
|
/*
|
|
* Find the handler for the prefix and dispatch its set() operation to remove
|
|
* any associated extended attribute.
|
|
*/
|
|
int
|
|
generic_removexattr(struct dentry *dentry, const char *name)
|
|
{
|
|
const struct xattr_handler *handler;
|
|
|
|
handler = xattr_resolve_name(dentry->d_sb->s_xattr, &name);
|
|
if (!handler)
|
|
return -EOPNOTSUPP;
|
|
return handler->set(dentry, name, NULL, 0,
|
|
XATTR_REPLACE, handler->flags);
|
|
}
|
|
|
|
EXPORT_SYMBOL(generic_getxattr);
|
|
EXPORT_SYMBOL(generic_listxattr);
|
|
EXPORT_SYMBOL(generic_setxattr);
|
|
EXPORT_SYMBOL(generic_removexattr);
|