*/
#include <linux/fs.h>
#include <linux/slab.h>
-#include <linux/smp_lock.h>
#include <linux/file.h>
#include <linux/xattr.h>
+#include <linux/mount.h>
#include <linux/namei.h>
#include <linux/security.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 a privileged user.
+ */
+ if (!strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN))
+ return (capable(CAP_SYS_ADMIN) ? 0 : -EPERM);
+
+ /* In user.* namespace, only regular files and directories can have
+ * extended attributes. For sticky directories, only the owner and
+ * privileged user 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 -EPERM;
+ 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;
+
+ 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 (!strncmp(name, XATTR_SECURITY_PREFIX,
+ XATTR_SECURITY_PREFIX_LEN)) {
+ 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);
+
+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);
+ return error;
+}
+EXPORT_SYMBOL_GPL(vfs_removexattr);
+
+
/*
* Extended attribute SET operations
*/
static long
-setxattr(struct dentry *d, char __user *name, void __user *value,
+setxattr(struct dentry *d, const char __user *name, const void __user *value,
size_t size, int flags)
{
int error;
if (size) {
if (size > XATTR_SIZE_MAX)
return -E2BIG;
- kvalue = kmalloc(size, GFP_KERNEL);
- if (!kvalue)
- return -ENOMEM;
- if (copy_from_user(kvalue, value, size)) {
- kfree(kvalue);
- return -EFAULT;
- }
+ kvalue = memdup_user(value, size);
+ if (IS_ERR(kvalue))
+ return PTR_ERR(kvalue);
}
- error = -EOPNOTSUPP;
- if (d->d_inode->i_op && d->d_inode->i_op->setxattr) {
- down(&d->d_inode->i_sem);
- error = security_inode_setxattr(d, kname, kvalue, size, flags);
- if (error)
- goto out;
- error = d->d_inode->i_op->setxattr(d, kname, kvalue, size, flags);
- if (!error)
- security_inode_post_setxattr(d, kname, kvalue, size, flags);
-out:
- up(&d->d_inode->i_sem);
- }
- if (kvalue)
- kfree(kvalue);
+ error = vfs_setxattr(d, kname, kvalue, size, flags);
+ kfree(kvalue);
return error;
}
-asmlinkage long
-sys_setxattr(char __user *path, char __user *name, void __user *value,
- size_t size, int flags)
+SYSCALL_DEFINE5(setxattr, const char __user *, pathname,
+ const char __user *, name, const void __user *, value,
+ size_t, size, int, flags)
{
- struct nameidata nd;
+ struct path path;
int error;
- error = user_path_walk(path, &nd);
+ error = user_path(pathname, &path);
if (error)
return error;
- error = setxattr(nd.dentry, name, value, size, flags);
- path_release(&nd);
+ 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;
}
-asmlinkage long
-sys_lsetxattr(char __user *path, char __user *name, void __user *value,
- size_t size, int flags)
+SYSCALL_DEFINE5(lsetxattr, const char __user *, pathname,
+ const char __user *, name, const void __user *, value,
+ size_t, size, int, flags)
{
- struct nameidata nd;
+ struct path path;
int error;
- error = user_path_walk_link(path, &nd);
+ error = user_lpath(pathname, &path);
if (error)
return error;
- error = setxattr(nd.dentry, name, value, size, flags);
- path_release(&nd);
+ 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;
}
-asmlinkage long
-sys_fsetxattr(int fd, char __user *name, void __user *value,
- size_t size, int flags)
+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;
- error = setxattr(f->f_dentry, name, value, size, flags);
+ 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, char __user *name, void __user *value, size_t size)
+getxattr(struct dentry *d, const char __user *name, void __user *value,
+ size_t size)
{
ssize_t error;
void *kvalue = NULL;
if (size) {
if (size > XATTR_SIZE_MAX)
size = XATTR_SIZE_MAX;
- kvalue = kmalloc(size, GFP_KERNEL);
+ kvalue = kzalloc(size, GFP_KERNEL);
if (!kvalue)
return -ENOMEM;
}
- error = -EOPNOTSUPP;
- if (d->d_inode->i_op && d->d_inode->i_op->getxattr) {
- error = security_inode_getxattr(d, kname);
- if (error)
- goto out;
- error = d->d_inode->i_op->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;
- }
+ 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;
}
-out:
- if (kvalue)
- kfree(kvalue);
+ kfree(kvalue);
return error;
}
-asmlinkage ssize_t
-sys_getxattr(char __user *path, char __user *name, void __user *value,
- size_t size)
+SYSCALL_DEFINE4(getxattr, const char __user *, pathname,
+ const char __user *, name, void __user *, value, size_t, size)
{
- struct nameidata nd;
+ struct path path;
ssize_t error;
- error = user_path_walk(path, &nd);
+ error = user_path(pathname, &path);
if (error)
return error;
- error = getxattr(nd.dentry, name, value, size);
- path_release(&nd);
+ error = getxattr(path.dentry, name, value, size);
+ path_put(&path);
return error;
}
-asmlinkage ssize_t
-sys_lgetxattr(char __user *path, char __user *name, void __user *value,
- size_t size)
+SYSCALL_DEFINE4(lgetxattr, const char __user *, pathname,
+ const char __user *, name, void __user *, value, size_t, size)
{
- struct nameidata nd;
+ struct path path;
ssize_t error;
- error = user_path_walk_link(path, &nd);
+ error = user_lpath(pathname, &path);
if (error)
return error;
- error = getxattr(nd.dentry, name, value, size);
- path_release(&nd);
+ error = getxattr(path.dentry, name, value, size);
+ path_put(&path);
return error;
}
-asmlinkage ssize_t
-sys_fgetxattr(int fd, char __user *name, void __user *value, size_t size)
+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;
- error = getxattr(f->f_dentry, name, value, size);
+ audit_inode(NULL, f->f_path.dentry);
+ error = getxattr(f->f_path.dentry, name, value, size);
fput(f);
return error;
}
return -ENOMEM;
}
- error = -EOPNOTSUPP;
- if (d->d_inode->i_op && d->d_inode->i_op->listxattr) {
- error = security_inode_listxattr(d);
- if (error)
- goto out;
- error = d->d_inode->i_op->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;
- }
+ 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;
}
-out:
- if (klist)
- kfree(klist);
+ kfree(klist);
return error;
}
-asmlinkage ssize_t
-sys_listxattr(char __user *path, char __user *list, size_t size)
+SYSCALL_DEFINE3(listxattr, const char __user *, pathname, char __user *, list,
+ size_t, size)
{
- struct nameidata nd;
+ struct path path;
ssize_t error;
- error = user_path_walk(path, &nd);
+ error = user_path(pathname, &path);
if (error)
return error;
- error = listxattr(nd.dentry, list, size);
- path_release(&nd);
+ error = listxattr(path.dentry, list, size);
+ path_put(&path);
return error;
}
-asmlinkage ssize_t
-sys_llistxattr(char __user *path, char __user *list, size_t size)
+SYSCALL_DEFINE3(llistxattr, const char __user *, pathname, char __user *, list,
+ size_t, size)
{
- struct nameidata nd;
+ struct path path;
ssize_t error;
- error = user_path_walk_link(path, &nd);
+ error = user_lpath(pathname, &path);
if (error)
return error;
- error = listxattr(nd.dentry, list, size);
- path_release(&nd);
+ error = listxattr(path.dentry, list, size);
+ path_put(&path);
return error;
}
-asmlinkage ssize_t
-sys_flistxattr(int fd, char __user *list, size_t size)
+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;
- error = listxattr(f->f_dentry, list, size);
+ 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, char __user *name)
+removexattr(struct dentry *d, const char __user *name)
{
int error;
char kname[XATTR_NAME_MAX + 1];
if (error < 0)
return error;
- error = -EOPNOTSUPP;
- if (d->d_inode->i_op && d->d_inode->i_op->removexattr) {
- error = security_inode_removexattr(d, kname);
- if (error)
- goto out;
- down(&d->d_inode->i_sem);
- error = d->d_inode->i_op->removexattr(d, kname);
- up(&d->d_inode->i_sem);
- }
-out:
- return error;
+ return vfs_removexattr(d, kname);
}
-asmlinkage long
-sys_removexattr(char __user *path, char __user *name)
+SYSCALL_DEFINE2(removexattr, const char __user *, pathname,
+ const char __user *, name)
{
- struct nameidata nd;
+ struct path path;
int error;
- error = user_path_walk(path, &nd);
+ error = user_path(pathname, &path);
if (error)
return error;
- error = removexattr(nd.dentry, name);
- path_release(&nd);
+ error = mnt_want_write(path.mnt);
+ if (!error) {
+ error = removexattr(path.dentry, name);
+ mnt_drop_write(path.mnt);
+ }
+ path_put(&path);
return error;
}
-asmlinkage long
-sys_lremovexattr(char __user *path, char __user *name)
+SYSCALL_DEFINE2(lremovexattr, const char __user *, pathname,
+ const char __user *, name)
{
- struct nameidata nd;
+ struct path path;
int error;
- error = user_path_walk_link(path, &nd);
+ error = user_lpath(pathname, &path);
if (error)
return error;
- error = removexattr(nd.dentry, name);
- path_release(&nd);
+ error = mnt_want_write(path.mnt);
+ if (!error) {
+ error = removexattr(path.dentry, name);
+ mnt_drop_write(path.mnt);
+ }
+ path_put(&path);
return error;
}
-asmlinkage long
-sys_fremovexattr(int fd, char __user *name)
+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;
- error = removexattr(f->f_dentry, name);
+ 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;
}
/*
* Find the xattr_handler with the matching prefix.
*/
-static struct xattr_handler *
-xattr_resolve_name(struct xattr_handler **handlers, const char **name)
+static const struct xattr_handler *
+xattr_resolve_name(const struct xattr_handler **handlers, const char **name)
{
- struct xattr_handler *handler;
+ const struct xattr_handler *handler;
if (!*name)
return NULL;
ssize_t
generic_getxattr(struct dentry *dentry, const char *name, void *buffer, size_t size)
{
- struct xattr_handler *handler;
- struct inode *inode = dentry->d_inode;
+ const struct xattr_handler *handler;
- handler = xattr_resolve_name(inode->i_sb->s_xattr, &name);
+ handler = xattr_resolve_name(dentry->d_sb->s_xattr, &name);
if (!handler)
return -EOPNOTSUPP;
- return handler->get(inode, name, buffer, size);
+ return handler->get(dentry, name, buffer, size, handler->flags);
}
/*
ssize_t
generic_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size)
{
- struct inode *inode = dentry->d_inode;
- struct xattr_handler *handler, **handlers = inode->i_sb->s_xattr;
+ 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(inode, NULL, 0, NULL, 0);
+ 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(inode, buf, buffer_size, NULL, 0);
+ size = handler->list(dentry, buf, buffer_size,
+ NULL, 0, handler->flags);
if (size > buffer_size)
return -ERANGE;
buf += size;
int
generic_setxattr(struct dentry *dentry, const char *name, const void *value, size_t size, int flags)
{
- struct xattr_handler *handler;
- struct inode *inode = dentry->d_inode;
+ const struct xattr_handler *handler;
if (size == 0)
value = ""; /* empty EA, do not remove */
- handler = xattr_resolve_name(inode->i_sb->s_xattr, &name);
+ handler = xattr_resolve_name(dentry->d_sb->s_xattr, &name);
if (!handler)
return -EOPNOTSUPP;
- return handler->set(inode, name, value, size, flags);
+ return handler->set(dentry, name, value, size, 0, handler->flags);
}
/*
int
generic_removexattr(struct dentry *dentry, const char *name)
{
- struct xattr_handler *handler;
- struct inode *inode = dentry->d_inode;
+ const struct xattr_handler *handler;
- handler = xattr_resolve_name(inode->i_sb->s_xattr, &name);
+ handler = xattr_resolve_name(dentry->d_sb->s_xattr, &name);
if (!handler)
return -EOPNOTSUPP;
- return handler->set(inode, name, NULL, 0, XATTR_REPLACE);
+ return handler->set(dentry, name, NULL, 0,
+ XATTR_REPLACE, handler->flags);
}
EXPORT_SYMBOL(generic_getxattr);
Code Review / linux-2.6.git / blobdiff