*/
#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) && !is_owner_or_cap(inode))
+ return -EPERM;
+ }
+
+ return permission(inode, mask, NULL);
+}
+
+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 = -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);
+ }
+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 && 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;
}
}
- down(&d->d_inode->i_sem);
- error = security_inode_setxattr(d, kname, kvalue, size, flags);
- if (error)
- goto out;
- error = -EOPNOTSUPP;
- if (d->d_inode->i_op && d->d_inode->i_op->setxattr) {
- error = d->d_inode->i_op->setxattr(d, kname, kvalue,
- size, flags);
- if (!error) {
- fsnotify_xattr(d);
- security_inode_post_setxattr(d, kname, kvalue,
- size, flags);
- }
- } else if (!strncmp(kname, XATTR_SECURITY_PREFIX,
- sizeof XATTR_SECURITY_PREFIX - 1)) {
- const char *suffix = kname + sizeof XATTR_SECURITY_PREFIX - 1;
- error = security_inode_setsecurity(d->d_inode, suffix, kvalue,
- size, flags);
- if (!error)
- fsnotify_xattr(d);
- }
-out:
- up(&d->d_inode->i_sem);
+ 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)
+sys_setxattr(const char __user *path, const char __user *name,
+ const void __user *value, size_t size, int flags)
{
struct nameidata nd;
int error;
error = user_path_walk(path, &nd);
if (error)
return error;
- error = setxattr(nd.dentry, name, value, size, flags);
- path_release(&nd);
+ error = mnt_want_write(nd.path.mnt);
+ if (!error) {
+ error = setxattr(nd.path.dentry, name, value, size, flags);
+ mnt_drop_write(nd.path.mnt);
+ }
+ path_put(&nd.path);
return error;
}
asmlinkage long
-sys_lsetxattr(char __user *path, char __user *name, void __user *value,
- size_t size, int flags)
+sys_lsetxattr(const char __user *path, const char __user *name,
+ const void __user *value, size_t size, int flags)
{
struct nameidata nd;
int error;
error = user_path_walk_link(path, &nd);
if (error)
return error;
- error = setxattr(nd.dentry, name, value, size, flags);
- path_release(&nd);
+ error = mnt_want_write(nd.path.mnt);
+ if (!error) {
+ error = setxattr(nd.path.dentry, name, value, size, flags);
+ mnt_drop_write(nd.path.mnt);
+ }
+ path_put(&nd.path);
return error;
}
asmlinkage long
-sys_fsetxattr(int fd, char __user *name, void __user *value,
+sys_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(f->f_path.mnt);
+ 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;
return -ENOMEM;
}
- error = security_inode_getxattr(d, kname);
- if (error)
- goto out;
- error = -EOPNOTSUPP;
- if (d->d_inode->i_op && d->d_inode->i_op->getxattr)
- error = d->d_inode->i_op->getxattr(d, kname, kvalue, size);
-
- if (!strncmp(kname, XATTR_SECURITY_PREFIX,
- sizeof XATTR_SECURITY_PREFIX - 1)) {
- const char *suffix = kname + sizeof XATTR_SECURITY_PREFIX - 1;
- int rv = security_inode_getsecurity(d->d_inode, suffix, kvalue,
- size, error);
- /* Security module active: overwrite error value */
- if (rv != -EOPNOTSUPP)
- error = rv;
- }
+ error = vfs_getxattr(d, kname, kvalue, size);
if (error > 0) {
if (size && copy_to_user(value, kvalue, error))
error = -EFAULT;
than XATTR_SIZE_MAX bytes. Not possible. */
error = -E2BIG;
}
-out:
kfree(kvalue);
return error;
}
asmlinkage ssize_t
-sys_getxattr(char __user *path, char __user *name, void __user *value,
- size_t size)
+sys_getxattr(const char __user *path, const char __user *name,
+ void __user *value, size_t size)
{
struct nameidata nd;
ssize_t error;
error = user_path_walk(path, &nd);
if (error)
return error;
- error = getxattr(nd.dentry, name, value, size);
- path_release(&nd);
+ error = getxattr(nd.path.dentry, name, value, size);
+ path_put(&nd.path);
return error;
}
asmlinkage ssize_t
-sys_lgetxattr(char __user *path, char __user *name, void __user *value,
+sys_lgetxattr(const char __user *path, const char __user *name, void __user *value,
size_t size)
{
struct nameidata nd;
error = user_path_walk_link(path, &nd);
if (error)
return error;
- error = getxattr(nd.dentry, name, value, size);
- path_release(&nd);
+ error = getxattr(nd.path.dentry, name, value, size);
+ path_put(&nd.path);
return error;
}
asmlinkage ssize_t
-sys_fgetxattr(int fd, char __user *name, void __user *value, size_t size)
+sys_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 = security_inode_listxattr(d);
- if (error)
- goto out;
- error = -EOPNOTSUPP;
- if (d->d_inode->i_op && d->d_inode->i_op->listxattr) {
- error = d->d_inode->i_op->listxattr(d, klist, size);
- } else {
- error = security_inode_listsecurity(d->d_inode, klist, size);
- if (size && error > size)
- error = -ERANGE;
- }
+ error = vfs_listxattr(d, klist, size);
if (error > 0) {
if (size && copy_to_user(list, klist, error))
error = -EFAULT;
than XATTR_LIST_MAX bytes. Not possible. */
error = -E2BIG;
}
-out:
kfree(klist);
return error;
}
asmlinkage ssize_t
-sys_listxattr(char __user *path, char __user *list, size_t size)
+sys_listxattr(const char __user *path, char __user *list, size_t size)
{
struct nameidata nd;
ssize_t error;
error = user_path_walk(path, &nd);
if (error)
return error;
- error = listxattr(nd.dentry, list, size);
- path_release(&nd);
+ error = listxattr(nd.path.dentry, list, size);
+ path_put(&nd.path);
return error;
}
asmlinkage ssize_t
-sys_llistxattr(char __user *path, char __user *list, size_t size)
+sys_llistxattr(const char __user *path, char __user *list, size_t size)
{
struct nameidata nd;
ssize_t error;
error = user_path_walk_link(path, &nd);
if (error)
return error;
- error = listxattr(nd.dentry, list, size);
- path_release(&nd);
+ error = listxattr(nd.path.dentry, list, size);
+ path_put(&nd.path);
return error;
}
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);
- if (!error)
- fsnotify_xattr(d);
- }
-out:
- return error;
+ return vfs_removexattr(d, kname);
}
asmlinkage long
-sys_removexattr(char __user *path, char __user *name)
+sys_removexattr(const char __user *path, const char __user *name)
{
struct nameidata nd;
int error;
error = user_path_walk(path, &nd);
if (error)
return error;
- error = removexattr(nd.dentry, name);
- path_release(&nd);
+ error = mnt_want_write(nd.path.mnt);
+ if (!error) {
+ error = removexattr(nd.path.dentry, name);
+ mnt_drop_write(nd.path.mnt);
+ }
+ path_put(&nd.path);
return error;
}
asmlinkage long
-sys_lremovexattr(char __user *path, char __user *name)
+sys_lremovexattr(const char __user *path, const char __user *name)
{
struct nameidata nd;
int error;
error = user_path_walk_link(path, &nd);
if (error)
return error;
- error = removexattr(nd.dentry, name);
- path_release(&nd);
+ error = mnt_want_write(nd.path.mnt);
+ if (!error) {
+ error = removexattr(nd.path.dentry, name);
+ mnt_drop_write(nd.path.mnt);
+ }
+ path_put(&nd.path);
return error;
}
asmlinkage long
-sys_fremovexattr(int fd, char __user *name)
+sys_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(f->f_path.mnt);
+ if (!error) {
+ error = removexattr(dentry, name);
+ mnt_drop_write(f->f_path.mnt);
+ }
fput(f);
return error;
}