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02bf43c7b7
-----BEGIN PGP SIGNATURE----- iHUEABYKAB0WIQRAhzRXHqcMeLMyaSiRxhvAZXjcogUCY5bw/wAKCRCRxhvAZXjc ol79AQCsHS9s78dLUvdasfQ1023dyF9zaQ8XGkDO6tRssJzGAAD7B8odxDsfQgjQ Qzzn9YPZVUgHjd4xBg21UVPmRP5snwQ= =wYgr -----END PGP SIGNATURE----- Merge tag 'fs.xattr.simple.rework.rbtree.rwlock.v6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/idmapping Pull simple-xattr updates from Christian Brauner: "This ports the simple xattr infrastucture to rely on a simple rbtree protected by a read-write lock instead of a linked list protected by a spinlock. A while ago we received reports about scaling issues for filesystems using the simple xattr infrastructure that also support setting a larger number of xattrs. Specifically, cgroups and tmpfs. Both cgroupfs and tmpfs can be mounted by unprivileged users in unprivileged containers and root in an unprivileged container can set an unrestricted number of security.* xattrs and privileged users can also set unlimited trusted.* xattrs. A few more words on further that below. Other xattrs such as user.* are restricted for kernfs-based instances to a fairly limited number. As there are apparently users that have a fairly large number of xattrs we should scale a bit better. Using a simple linked list protected by a spinlock used for set, get, and list operations doesn't scale well if users use a lot of xattrs even if it's not a crazy number. Let's switch to a simple rbtree protected by a rwlock. It scales way better and gets rid of the perf issues some people reported. We originally had fancier solutions even using an rcu+seqlock protected rbtree but we had concerns about being to clever and also that deletion from an rbtree with rcu+seqlock isn't entirely safe. The rbtree plus rwlock is perfectly fine. By far the most common operation is getting an xattr. While setting an xattr is not and should be comparatively rare. And listxattr() often only happens when copying xattrs between files or together with the contents to a new file. Holding a lock across listxattr() is unproblematic because it doesn't list the values of xattrs. It can only be used to list the names of all xattrs set on a file. And the number of xattr names that can be listed with listxattr() is limited to XATTR_LIST_MAX aka 65536 bytes. If a larger buffer is passed then vfs_listxattr() caps it to XATTR_LIST_MAX and if more xattr names are found it will return -E2BIG. In short, the maximum amount of memory that can be retrieved via listxattr() is limited and thus listxattr() bounded. Of course, the API is broken as documented on xattr(7) already. While I have no idea how the xattr api ended up in this state we should probably try to come up with something here at some point. An iterator pattern similar to readdir() as an alternative to listxattr() or something else. Right now it is extremly strange that users can set millions of xattrs but then can't use listxattr() to know which xattrs are actually set. And it's really trivial to do: for i in {1..1000000}; do setfattr -n security.$i -v $i ./file1; done And around 5000 xattrs it's impossible to use listxattr() to figure out which xattrs are actually set. So I have suggested that we try to limit the number of xattrs for simple xattrs at least. But that's a future patch and I don't consider it very urgent. A bonus of this port to rbtree+rwlock is that we shrink the memory consumption for users of the simple xattr infrastructure. This also adds kernel documentation to all the functions" * tag 'fs.xattr.simple.rework.rbtree.rwlock.v6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/idmapping: xattr: use rbtree for simple_xattrs
1392 lines
35 KiB
C
1392 lines
35 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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File: fs/xattr.c
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Extended attribute handling.
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Copyright (C) 2001 by Andreas Gruenbacher <a.gruenbacher@computer.org>
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Copyright (C) 2001 SGI - Silicon Graphics, Inc <linux-xfs@oss.sgi.com>
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Copyright (c) 2004 Red Hat, Inc., James Morris <jmorris@redhat.com>
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*/
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#include <linux/fs.h>
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#include <linux/slab.h>
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#include <linux/file.h>
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#include <linux/xattr.h>
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#include <linux/mount.h>
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#include <linux/namei.h>
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#include <linux/security.h>
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#include <linux/evm.h>
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#include <linux/syscalls.h>
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#include <linux/export.h>
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#include <linux/fsnotify.h>
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#include <linux/audit.h>
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#include <linux/vmalloc.h>
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#include <linux/posix_acl_xattr.h>
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#include <linux/uaccess.h>
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#include "internal.h"
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static const char *
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strcmp_prefix(const char *a, const char *a_prefix)
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{
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while (*a_prefix && *a == *a_prefix) {
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a++;
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a_prefix++;
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}
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return *a_prefix ? NULL : a;
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}
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/*
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* In order to implement different sets of xattr operations for each xattr
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* prefix, a filesystem should create a null-terminated array of struct
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* xattr_handler (one for each prefix) and hang a pointer to it off of the
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* s_xattr field of the superblock.
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*/
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#define for_each_xattr_handler(handlers, handler) \
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if (handlers) \
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for ((handler) = *(handlers)++; \
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(handler) != NULL; \
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(handler) = *(handlers)++)
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/*
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* Find the xattr_handler with the matching prefix.
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*/
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static const struct xattr_handler *
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xattr_resolve_name(struct inode *inode, const char **name)
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{
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const struct xattr_handler **handlers = inode->i_sb->s_xattr;
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const struct xattr_handler *handler;
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if (!(inode->i_opflags & IOP_XATTR)) {
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if (unlikely(is_bad_inode(inode)))
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return ERR_PTR(-EIO);
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return ERR_PTR(-EOPNOTSUPP);
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}
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for_each_xattr_handler(handlers, handler) {
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const char *n;
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n = strcmp_prefix(*name, xattr_prefix(handler));
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if (n) {
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if (!handler->prefix ^ !*n) {
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if (*n)
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continue;
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return ERR_PTR(-EINVAL);
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}
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*name = n;
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return handler;
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}
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}
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return ERR_PTR(-EOPNOTSUPP);
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}
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/**
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* may_write_xattr - check whether inode allows writing xattr
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* @mnt_userns: User namespace of the mount the inode was found from
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* @inode: the inode on which to set an xattr
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*
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* Check whether the inode allows writing xattrs. Specifically, we can never
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* set or remove an extended attribute on a read-only filesystem or on an
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* immutable / append-only inode.
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*
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* We also need to ensure that the inode has a mapping in the mount to
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* not risk writing back invalid i_{g,u}id values.
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*
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* Return: On success zero is returned. On error a negative errno is returned.
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*/
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int may_write_xattr(struct user_namespace *mnt_userns, struct inode *inode)
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{
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if (IS_IMMUTABLE(inode))
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return -EPERM;
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if (IS_APPEND(inode))
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return -EPERM;
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if (HAS_UNMAPPED_ID(mnt_userns, inode))
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return -EPERM;
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return 0;
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}
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/*
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* Check permissions for extended attribute access. This is a bit complicated
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* because different namespaces have very different rules.
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*/
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static int
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xattr_permission(struct user_namespace *mnt_userns, struct inode *inode,
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const char *name, int mask)
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{
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if (mask & MAY_WRITE) {
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int ret;
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ret = may_write_xattr(mnt_userns, inode);
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if (ret)
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return ret;
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}
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/*
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* No restriction for security.* and system.* from the VFS. Decision
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* on these is left to the underlying filesystem / security module.
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*/
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if (!strncmp(name, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN) ||
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!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
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return 0;
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/*
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* The trusted.* namespace can only be accessed by privileged users.
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*/
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if (!strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN)) {
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if (!capable(CAP_SYS_ADMIN))
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return (mask & MAY_WRITE) ? -EPERM : -ENODATA;
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return 0;
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}
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/*
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* In the user.* namespace, only regular files and directories can have
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* extended attributes. For sticky directories, only the owner and
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* privileged users can write attributes.
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*/
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if (!strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN)) {
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if (!S_ISREG(inode->i_mode) && !S_ISDIR(inode->i_mode))
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return (mask & MAY_WRITE) ? -EPERM : -ENODATA;
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if (S_ISDIR(inode->i_mode) && (inode->i_mode & S_ISVTX) &&
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(mask & MAY_WRITE) &&
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!inode_owner_or_capable(mnt_userns, inode))
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return -EPERM;
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}
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return inode_permission(mnt_userns, inode, mask);
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}
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/*
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* Look for any handler that deals with the specified namespace.
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*/
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int
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xattr_supported_namespace(struct inode *inode, const char *prefix)
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{
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const struct xattr_handler **handlers = inode->i_sb->s_xattr;
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const struct xattr_handler *handler;
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size_t preflen;
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if (!(inode->i_opflags & IOP_XATTR)) {
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if (unlikely(is_bad_inode(inode)))
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return -EIO;
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return -EOPNOTSUPP;
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}
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preflen = strlen(prefix);
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for_each_xattr_handler(handlers, handler) {
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if (!strncmp(xattr_prefix(handler), prefix, preflen))
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return 0;
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}
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return -EOPNOTSUPP;
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}
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EXPORT_SYMBOL(xattr_supported_namespace);
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int
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__vfs_setxattr(struct user_namespace *mnt_userns, struct dentry *dentry,
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struct inode *inode, const char *name, const void *value,
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size_t size, int flags)
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{
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const struct xattr_handler *handler;
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if (is_posix_acl_xattr(name))
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return -EOPNOTSUPP;
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handler = xattr_resolve_name(inode, &name);
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if (IS_ERR(handler))
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return PTR_ERR(handler);
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if (!handler->set)
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return -EOPNOTSUPP;
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if (size == 0)
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value = ""; /* empty EA, do not remove */
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return handler->set(handler, mnt_userns, dentry, inode, name, value,
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size, flags);
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}
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EXPORT_SYMBOL(__vfs_setxattr);
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/**
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* __vfs_setxattr_noperm - perform setxattr operation without performing
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* permission checks.
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*
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* @mnt_userns: user namespace of the mount the inode was found from
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* @dentry: object to perform setxattr on
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* @name: xattr name to set
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* @value: value to set @name to
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* @size: size of @value
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* @flags: flags to pass into filesystem operations
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*
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* returns the result of the internal setxattr or setsecurity operations.
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*
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* This function requires the caller to lock the inode's i_mutex before it
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* is executed. It also assumes that the caller will make the appropriate
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* permission checks.
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*/
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int __vfs_setxattr_noperm(struct user_namespace *mnt_userns,
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struct dentry *dentry, const char *name,
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const void *value, size_t size, int flags)
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{
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struct inode *inode = dentry->d_inode;
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int error = -EAGAIN;
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int issec = !strncmp(name, XATTR_SECURITY_PREFIX,
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XATTR_SECURITY_PREFIX_LEN);
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if (issec)
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inode->i_flags &= ~S_NOSEC;
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if (inode->i_opflags & IOP_XATTR) {
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error = __vfs_setxattr(mnt_userns, dentry, inode, name, value,
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size, flags);
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if (!error) {
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fsnotify_xattr(dentry);
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security_inode_post_setxattr(dentry, name, value,
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size, flags);
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}
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} else {
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if (unlikely(is_bad_inode(inode)))
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return -EIO;
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}
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if (error == -EAGAIN) {
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error = -EOPNOTSUPP;
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if (issec) {
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const char *suffix = name + XATTR_SECURITY_PREFIX_LEN;
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error = security_inode_setsecurity(inode, suffix, value,
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size, flags);
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if (!error)
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fsnotify_xattr(dentry);
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}
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}
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return error;
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}
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/**
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* __vfs_setxattr_locked - set an extended attribute while holding the inode
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* lock
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*
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* @mnt_userns: user namespace of the mount of the target inode
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* @dentry: object to perform setxattr on
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* @name: xattr name to set
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* @value: value to set @name to
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* @size: size of @value
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* @flags: flags to pass into filesystem operations
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* @delegated_inode: on return, will contain an inode pointer that
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* a delegation was broken on, NULL if none.
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*/
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int
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__vfs_setxattr_locked(struct user_namespace *mnt_userns, struct dentry *dentry,
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const char *name, const void *value, size_t size,
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int flags, struct inode **delegated_inode)
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{
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struct inode *inode = dentry->d_inode;
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int error;
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error = xattr_permission(mnt_userns, inode, name, MAY_WRITE);
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if (error)
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return error;
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error = security_inode_setxattr(mnt_userns, dentry, name, value, size,
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flags);
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if (error)
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goto out;
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error = try_break_deleg(inode, delegated_inode);
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if (error)
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goto out;
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error = __vfs_setxattr_noperm(mnt_userns, dentry, name, value,
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size, flags);
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out:
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return error;
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}
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EXPORT_SYMBOL_GPL(__vfs_setxattr_locked);
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int
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vfs_setxattr(struct user_namespace *mnt_userns, struct dentry *dentry,
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const char *name, const void *value, size_t size, int flags)
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{
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struct inode *inode = dentry->d_inode;
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struct inode *delegated_inode = NULL;
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const void *orig_value = value;
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int error;
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if (size && strcmp(name, XATTR_NAME_CAPS) == 0) {
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error = cap_convert_nscap(mnt_userns, dentry, &value, size);
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if (error < 0)
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return error;
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size = error;
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}
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retry_deleg:
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inode_lock(inode);
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error = __vfs_setxattr_locked(mnt_userns, dentry, name, value, size,
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flags, &delegated_inode);
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inode_unlock(inode);
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if (delegated_inode) {
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error = break_deleg_wait(&delegated_inode);
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if (!error)
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goto retry_deleg;
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|
}
|
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if (value != orig_value)
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kfree(value);
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return error;
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}
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EXPORT_SYMBOL_GPL(vfs_setxattr);
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|
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static ssize_t
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xattr_getsecurity(struct user_namespace *mnt_userns, struct inode *inode,
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const char *name, void *value, size_t size)
|
|
{
|
|
void *buffer = NULL;
|
|
ssize_t len;
|
|
|
|
if (!value || !size) {
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len = security_inode_getsecurity(mnt_userns, inode, name,
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&buffer, false);
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goto out_noalloc;
|
|
}
|
|
|
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len = security_inode_getsecurity(mnt_userns, inode, name, &buffer,
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true);
|
|
if (len < 0)
|
|
return len;
|
|
if (size < len) {
|
|
len = -ERANGE;
|
|
goto out;
|
|
}
|
|
memcpy(value, buffer, len);
|
|
out:
|
|
kfree(buffer);
|
|
out_noalloc:
|
|
return len;
|
|
}
|
|
|
|
/*
|
|
* 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. The xattr value buffer should
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|
* always be freed by the caller, even on error.
|
|
*
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|
* Returns the result of alloc, if failed, or the getxattr operation.
|
|
*/
|
|
int
|
|
vfs_getxattr_alloc(struct user_namespace *mnt_userns, struct dentry *dentry,
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|
const char *name, char **xattr_value, size_t xattr_size,
|
|
gfp_t flags)
|
|
{
|
|
const struct xattr_handler *handler;
|
|
struct inode *inode = dentry->d_inode;
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|
char *value = *xattr_value;
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|
int error;
|
|
|
|
error = xattr_permission(mnt_userns, inode, name, MAY_READ);
|
|
if (error)
|
|
return error;
|
|
|
|
handler = xattr_resolve_name(inode, &name);
|
|
if (IS_ERR(handler))
|
|
return PTR_ERR(handler);
|
|
if (!handler->get)
|
|
return -EOPNOTSUPP;
|
|
error = handler->get(handler, dentry, inode, 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 = handler->get(handler, dentry, inode, name, value, error);
|
|
*xattr_value = value;
|
|
return error;
|
|
}
|
|
|
|
ssize_t
|
|
__vfs_getxattr(struct dentry *dentry, struct inode *inode, const char *name,
|
|
void *value, size_t size)
|
|
{
|
|
const struct xattr_handler *handler;
|
|
|
|
if (is_posix_acl_xattr(name))
|
|
return -EOPNOTSUPP;
|
|
|
|
handler = xattr_resolve_name(inode, &name);
|
|
if (IS_ERR(handler))
|
|
return PTR_ERR(handler);
|
|
if (!handler->get)
|
|
return -EOPNOTSUPP;
|
|
return handler->get(handler, dentry, inode, name, value, size);
|
|
}
|
|
EXPORT_SYMBOL(__vfs_getxattr);
|
|
|
|
ssize_t
|
|
vfs_getxattr(struct user_namespace *mnt_userns, struct dentry *dentry,
|
|
const char *name, void *value, size_t size)
|
|
{
|
|
struct inode *inode = dentry->d_inode;
|
|
int error;
|
|
|
|
error = xattr_permission(mnt_userns, 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(mnt_userns, inode, suffix, value,
|
|
size);
|
|
/*
|
|
* Only overwrite the return value if a security module
|
|
* is actually active.
|
|
*/
|
|
if (ret == -EOPNOTSUPP)
|
|
goto nolsm;
|
|
return ret;
|
|
}
|
|
nolsm:
|
|
return __vfs_getxattr(dentry, inode, name, value, size);
|
|
}
|
|
EXPORT_SYMBOL_GPL(vfs_getxattr);
|
|
|
|
ssize_t
|
|
vfs_listxattr(struct dentry *dentry, char *list, size_t size)
|
|
{
|
|
struct inode *inode = d_inode(dentry);
|
|
ssize_t error;
|
|
|
|
error = security_inode_listxattr(dentry);
|
|
if (error)
|
|
return error;
|
|
if (inode->i_op->listxattr && (inode->i_opflags & IOP_XATTR)) {
|
|
error = inode->i_op->listxattr(dentry, list, size);
|
|
} else {
|
|
error = security_inode_listsecurity(inode, list, size);
|
|
if (size && error > size)
|
|
error = -ERANGE;
|
|
}
|
|
return error;
|
|
}
|
|
EXPORT_SYMBOL_GPL(vfs_listxattr);
|
|
|
|
int
|
|
__vfs_removexattr(struct user_namespace *mnt_userns, struct dentry *dentry,
|
|
const char *name)
|
|
{
|
|
struct inode *inode = d_inode(dentry);
|
|
const struct xattr_handler *handler;
|
|
|
|
if (is_posix_acl_xattr(name))
|
|
return -EOPNOTSUPP;
|
|
|
|
handler = xattr_resolve_name(inode, &name);
|
|
if (IS_ERR(handler))
|
|
return PTR_ERR(handler);
|
|
if (!handler->set)
|
|
return -EOPNOTSUPP;
|
|
return handler->set(handler, mnt_userns, dentry, inode, name, NULL, 0,
|
|
XATTR_REPLACE);
|
|
}
|
|
EXPORT_SYMBOL(__vfs_removexattr);
|
|
|
|
/**
|
|
* __vfs_removexattr_locked - set an extended attribute while holding the inode
|
|
* lock
|
|
*
|
|
* @mnt_userns: user namespace of the mount of the target inode
|
|
* @dentry: object to perform setxattr on
|
|
* @name: name of xattr to remove
|
|
* @delegated_inode: on return, will contain an inode pointer that
|
|
* a delegation was broken on, NULL if none.
|
|
*/
|
|
int
|
|
__vfs_removexattr_locked(struct user_namespace *mnt_userns,
|
|
struct dentry *dentry, const char *name,
|
|
struct inode **delegated_inode)
|
|
{
|
|
struct inode *inode = dentry->d_inode;
|
|
int error;
|
|
|
|
error = xattr_permission(mnt_userns, inode, name, MAY_WRITE);
|
|
if (error)
|
|
return error;
|
|
|
|
error = security_inode_removexattr(mnt_userns, dentry, name);
|
|
if (error)
|
|
goto out;
|
|
|
|
error = try_break_deleg(inode, delegated_inode);
|
|
if (error)
|
|
goto out;
|
|
|
|
error = __vfs_removexattr(mnt_userns, dentry, name);
|
|
|
|
if (!error) {
|
|
fsnotify_xattr(dentry);
|
|
evm_inode_post_removexattr(dentry, name);
|
|
}
|
|
|
|
out:
|
|
return error;
|
|
}
|
|
EXPORT_SYMBOL_GPL(__vfs_removexattr_locked);
|
|
|
|
int
|
|
vfs_removexattr(struct user_namespace *mnt_userns, struct dentry *dentry,
|
|
const char *name)
|
|
{
|
|
struct inode *inode = dentry->d_inode;
|
|
struct inode *delegated_inode = NULL;
|
|
int error;
|
|
|
|
retry_deleg:
|
|
inode_lock(inode);
|
|
error = __vfs_removexattr_locked(mnt_userns, dentry,
|
|
name, &delegated_inode);
|
|
inode_unlock(inode);
|
|
|
|
if (delegated_inode) {
|
|
error = break_deleg_wait(&delegated_inode);
|
|
if (!error)
|
|
goto retry_deleg;
|
|
}
|
|
|
|
return error;
|
|
}
|
|
EXPORT_SYMBOL_GPL(vfs_removexattr);
|
|
|
|
/*
|
|
* Extended attribute SET operations
|
|
*/
|
|
|
|
int setxattr_copy(const char __user *name, struct xattr_ctx *ctx)
|
|
{
|
|
int error;
|
|
|
|
if (ctx->flags & ~(XATTR_CREATE|XATTR_REPLACE))
|
|
return -EINVAL;
|
|
|
|
error = strncpy_from_user(ctx->kname->name, name,
|
|
sizeof(ctx->kname->name));
|
|
if (error == 0 || error == sizeof(ctx->kname->name))
|
|
return -ERANGE;
|
|
if (error < 0)
|
|
return error;
|
|
|
|
error = 0;
|
|
if (ctx->size) {
|
|
if (ctx->size > XATTR_SIZE_MAX)
|
|
return -E2BIG;
|
|
|
|
ctx->kvalue = vmemdup_user(ctx->cvalue, ctx->size);
|
|
if (IS_ERR(ctx->kvalue)) {
|
|
error = PTR_ERR(ctx->kvalue);
|
|
ctx->kvalue = NULL;
|
|
}
|
|
}
|
|
|
|
return error;
|
|
}
|
|
|
|
int do_setxattr(struct mnt_idmap *idmap, struct dentry *dentry,
|
|
struct xattr_ctx *ctx)
|
|
{
|
|
if (is_posix_acl_xattr(ctx->kname->name))
|
|
return do_set_acl(idmap, dentry, ctx->kname->name,
|
|
ctx->kvalue, ctx->size);
|
|
|
|
return vfs_setxattr(mnt_idmap_owner(idmap), dentry, ctx->kname->name,
|
|
ctx->kvalue, ctx->size, ctx->flags);
|
|
}
|
|
|
|
static long
|
|
setxattr(struct mnt_idmap *idmap, struct dentry *d,
|
|
const char __user *name, const void __user *value, size_t size,
|
|
int flags)
|
|
{
|
|
struct xattr_name kname;
|
|
struct xattr_ctx ctx = {
|
|
.cvalue = value,
|
|
.kvalue = NULL,
|
|
.size = size,
|
|
.kname = &kname,
|
|
.flags = flags,
|
|
};
|
|
int error;
|
|
|
|
error = setxattr_copy(name, &ctx);
|
|
if (error)
|
|
return error;
|
|
|
|
error = do_setxattr(idmap, d, &ctx);
|
|
|
|
kvfree(ctx.kvalue);
|
|
return error;
|
|
}
|
|
|
|
static int path_setxattr(const char __user *pathname,
|
|
const char __user *name, const void __user *value,
|
|
size_t size, int flags, unsigned int lookup_flags)
|
|
{
|
|
struct path path;
|
|
int error;
|
|
|
|
retry:
|
|
error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path);
|
|
if (error)
|
|
return error;
|
|
error = mnt_want_write(path.mnt);
|
|
if (!error) {
|
|
error = setxattr(mnt_idmap(path.mnt), path.dentry, name,
|
|
value, size, flags);
|
|
mnt_drop_write(path.mnt);
|
|
}
|
|
path_put(&path);
|
|
if (retry_estale(error, lookup_flags)) {
|
|
lookup_flags |= LOOKUP_REVAL;
|
|
goto retry;
|
|
}
|
|
return error;
|
|
}
|
|
|
|
SYSCALL_DEFINE5(setxattr, const char __user *, pathname,
|
|
const char __user *, name, const void __user *, value,
|
|
size_t, size, int, flags)
|
|
{
|
|
return path_setxattr(pathname, name, value, size, flags, LOOKUP_FOLLOW);
|
|
}
|
|
|
|
SYSCALL_DEFINE5(lsetxattr, const char __user *, pathname,
|
|
const char __user *, name, const void __user *, value,
|
|
size_t, size, int, flags)
|
|
{
|
|
return path_setxattr(pathname, name, value, size, flags, 0);
|
|
}
|
|
|
|
SYSCALL_DEFINE5(fsetxattr, int, fd, const char __user *, name,
|
|
const void __user *,value, size_t, size, int, flags)
|
|
{
|
|
struct fd f = fdget(fd);
|
|
int error = -EBADF;
|
|
|
|
if (!f.file)
|
|
return error;
|
|
audit_file(f.file);
|
|
error = mnt_want_write_file(f.file);
|
|
if (!error) {
|
|
error = setxattr(file_mnt_idmap(f.file),
|
|
f.file->f_path.dentry, name,
|
|
value, size, flags);
|
|
mnt_drop_write_file(f.file);
|
|
}
|
|
fdput(f);
|
|
return error;
|
|
}
|
|
|
|
/*
|
|
* Extended attribute GET operations
|
|
*/
|
|
ssize_t
|
|
do_getxattr(struct mnt_idmap *idmap, struct dentry *d,
|
|
struct xattr_ctx *ctx)
|
|
{
|
|
ssize_t error;
|
|
char *kname = ctx->kname->name;
|
|
|
|
if (ctx->size) {
|
|
if (ctx->size > XATTR_SIZE_MAX)
|
|
ctx->size = XATTR_SIZE_MAX;
|
|
ctx->kvalue = kvzalloc(ctx->size, GFP_KERNEL);
|
|
if (!ctx->kvalue)
|
|
return -ENOMEM;
|
|
}
|
|
|
|
if (is_posix_acl_xattr(ctx->kname->name))
|
|
error = do_get_acl(idmap, d, kname, ctx->kvalue, ctx->size);
|
|
else
|
|
error = vfs_getxattr(mnt_idmap_owner(idmap), d, kname,
|
|
ctx->kvalue, ctx->size);
|
|
if (error > 0) {
|
|
if (ctx->size && copy_to_user(ctx->value, ctx->kvalue, error))
|
|
error = -EFAULT;
|
|
} else if (error == -ERANGE && ctx->size >= XATTR_SIZE_MAX) {
|
|
/* The file system tried to returned a value bigger
|
|
than XATTR_SIZE_MAX bytes. Not possible. */
|
|
error = -E2BIG;
|
|
}
|
|
|
|
return error;
|
|
}
|
|
|
|
static ssize_t
|
|
getxattr(struct mnt_idmap *idmap, struct dentry *d,
|
|
const char __user *name, void __user *value, size_t size)
|
|
{
|
|
ssize_t error;
|
|
struct xattr_name kname;
|
|
struct xattr_ctx ctx = {
|
|
.value = value,
|
|
.kvalue = NULL,
|
|
.size = size,
|
|
.kname = &kname,
|
|
.flags = 0,
|
|
};
|
|
|
|
error = strncpy_from_user(kname.name, name, sizeof(kname.name));
|
|
if (error == 0 || error == sizeof(kname.name))
|
|
error = -ERANGE;
|
|
if (error < 0)
|
|
return error;
|
|
|
|
error = do_getxattr(idmap, d, &ctx);
|
|
|
|
kvfree(ctx.kvalue);
|
|
return error;
|
|
}
|
|
|
|
static ssize_t path_getxattr(const char __user *pathname,
|
|
const char __user *name, void __user *value,
|
|
size_t size, unsigned int lookup_flags)
|
|
{
|
|
struct path path;
|
|
ssize_t error;
|
|
retry:
|
|
error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path);
|
|
if (error)
|
|
return error;
|
|
error = getxattr(mnt_idmap(path.mnt), path.dentry, name, value, size);
|
|
path_put(&path);
|
|
if (retry_estale(error, lookup_flags)) {
|
|
lookup_flags |= LOOKUP_REVAL;
|
|
goto retry;
|
|
}
|
|
return error;
|
|
}
|
|
|
|
SYSCALL_DEFINE4(getxattr, const char __user *, pathname,
|
|
const char __user *, name, void __user *, value, size_t, size)
|
|
{
|
|
return path_getxattr(pathname, name, value, size, LOOKUP_FOLLOW);
|
|
}
|
|
|
|
SYSCALL_DEFINE4(lgetxattr, const char __user *, pathname,
|
|
const char __user *, name, void __user *, value, size_t, size)
|
|
{
|
|
return path_getxattr(pathname, name, value, size, 0);
|
|
}
|
|
|
|
SYSCALL_DEFINE4(fgetxattr, int, fd, const char __user *, name,
|
|
void __user *, value, size_t, size)
|
|
{
|
|
struct fd f = fdget(fd);
|
|
ssize_t error = -EBADF;
|
|
|
|
if (!f.file)
|
|
return error;
|
|
audit_file(f.file);
|
|
error = getxattr(file_mnt_idmap(f.file), f.file->f_path.dentry,
|
|
name, value, size);
|
|
fdput(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 = kvmalloc(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;
|
|
}
|
|
|
|
kvfree(klist);
|
|
|
|
return error;
|
|
}
|
|
|
|
static ssize_t path_listxattr(const char __user *pathname, char __user *list,
|
|
size_t size, unsigned int lookup_flags)
|
|
{
|
|
struct path path;
|
|
ssize_t error;
|
|
retry:
|
|
error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path);
|
|
if (error)
|
|
return error;
|
|
error = listxattr(path.dentry, list, size);
|
|
path_put(&path);
|
|
if (retry_estale(error, lookup_flags)) {
|
|
lookup_flags |= LOOKUP_REVAL;
|
|
goto retry;
|
|
}
|
|
return error;
|
|
}
|
|
|
|
SYSCALL_DEFINE3(listxattr, const char __user *, pathname, char __user *, list,
|
|
size_t, size)
|
|
{
|
|
return path_listxattr(pathname, list, size, LOOKUP_FOLLOW);
|
|
}
|
|
|
|
SYSCALL_DEFINE3(llistxattr, const char __user *, pathname, char __user *, list,
|
|
size_t, size)
|
|
{
|
|
return path_listxattr(pathname, list, size, 0);
|
|
}
|
|
|
|
SYSCALL_DEFINE3(flistxattr, int, fd, char __user *, list, size_t, size)
|
|
{
|
|
struct fd f = fdget(fd);
|
|
ssize_t error = -EBADF;
|
|
|
|
if (!f.file)
|
|
return error;
|
|
audit_file(f.file);
|
|
error = listxattr(f.file->f_path.dentry, list, size);
|
|
fdput(f);
|
|
return error;
|
|
}
|
|
|
|
/*
|
|
* Extended attribute REMOVE operations
|
|
*/
|
|
static long
|
|
removexattr(struct mnt_idmap *idmap, 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;
|
|
|
|
if (is_posix_acl_xattr(kname))
|
|
return vfs_remove_acl(mnt_idmap_owner(idmap), d, kname);
|
|
|
|
return vfs_removexattr(mnt_idmap_owner(idmap), d, kname);
|
|
}
|
|
|
|
static int path_removexattr(const char __user *pathname,
|
|
const char __user *name, unsigned int lookup_flags)
|
|
{
|
|
struct path path;
|
|
int error;
|
|
retry:
|
|
error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path);
|
|
if (error)
|
|
return error;
|
|
error = mnt_want_write(path.mnt);
|
|
if (!error) {
|
|
error = removexattr(mnt_idmap(path.mnt), path.dentry, name);
|
|
mnt_drop_write(path.mnt);
|
|
}
|
|
path_put(&path);
|
|
if (retry_estale(error, lookup_flags)) {
|
|
lookup_flags |= LOOKUP_REVAL;
|
|
goto retry;
|
|
}
|
|
return error;
|
|
}
|
|
|
|
SYSCALL_DEFINE2(removexattr, const char __user *, pathname,
|
|
const char __user *, name)
|
|
{
|
|
return path_removexattr(pathname, name, LOOKUP_FOLLOW);
|
|
}
|
|
|
|
SYSCALL_DEFINE2(lremovexattr, const char __user *, pathname,
|
|
const char __user *, name)
|
|
{
|
|
return path_removexattr(pathname, name, 0);
|
|
}
|
|
|
|
SYSCALL_DEFINE2(fremovexattr, int, fd, const char __user *, name)
|
|
{
|
|
struct fd f = fdget(fd);
|
|
int error = -EBADF;
|
|
|
|
if (!f.file)
|
|
return error;
|
|
audit_file(f.file);
|
|
error = mnt_want_write_file(f.file);
|
|
if (!error) {
|
|
error = removexattr(file_mnt_idmap(f.file),
|
|
f.file->f_path.dentry, name);
|
|
mnt_drop_write_file(f.file);
|
|
}
|
|
fdput(f);
|
|
return error;
|
|
}
|
|
|
|
/*
|
|
* 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) {
|
|
if (!handler->name ||
|
|
(handler->list && !handler->list(dentry)))
|
|
continue;
|
|
size += strlen(handler->name) + 1;
|
|
}
|
|
} else {
|
|
char *buf = buffer;
|
|
size_t len;
|
|
|
|
for_each_xattr_handler(handlers, handler) {
|
|
if (!handler->name ||
|
|
(handler->list && !handler->list(dentry)))
|
|
continue;
|
|
len = strlen(handler->name);
|
|
if (len + 1 > buffer_size)
|
|
return -ERANGE;
|
|
memcpy(buf, handler->name, len + 1);
|
|
buf += len + 1;
|
|
buffer_size -= len + 1;
|
|
}
|
|
size = buf - buffer;
|
|
}
|
|
return size;
|
|
}
|
|
EXPORT_SYMBOL(generic_listxattr);
|
|
|
|
/**
|
|
* xattr_full_name - Compute full attribute name from suffix
|
|
*
|
|
* @handler: handler of the xattr_handler operation
|
|
* @name: name passed to the xattr_handler operation
|
|
*
|
|
* The get and set xattr handler operations are called with the remainder of
|
|
* the attribute name after skipping the handler's prefix: for example, "foo"
|
|
* is passed to the get operation of a handler with prefix "user." to get
|
|
* attribute "user.foo". The full name is still "there" in the name though.
|
|
*
|
|
* Note: the list xattr handler operation when called from the vfs is passed a
|
|
* NULL name; some file systems use this operation internally, with varying
|
|
* semantics.
|
|
*/
|
|
const char *xattr_full_name(const struct xattr_handler *handler,
|
|
const char *name)
|
|
{
|
|
size_t prefix_len = strlen(xattr_prefix(handler));
|
|
|
|
return name - prefix_len;
|
|
}
|
|
EXPORT_SYMBOL(xattr_full_name);
|
|
|
|
/**
|
|
* free_simple_xattr - free an xattr object
|
|
* @xattr: the xattr object
|
|
*
|
|
* Free the xattr object. Can handle @xattr being NULL.
|
|
*/
|
|
static inline void free_simple_xattr(struct simple_xattr *xattr)
|
|
{
|
|
if (xattr)
|
|
kfree(xattr->name);
|
|
kvfree(xattr);
|
|
}
|
|
|
|
/**
|
|
* simple_xattr_alloc - allocate new xattr object
|
|
* @value: value of the xattr object
|
|
* @size: size of @value
|
|
*
|
|
* Allocate a new xattr object and initialize respective members. The caller is
|
|
* responsible for handling the name of the xattr.
|
|
*
|
|
* Return: On success a new xattr object is returned. On failure NULL is
|
|
* returned.
|
|
*/
|
|
struct simple_xattr *simple_xattr_alloc(const void *value, size_t size)
|
|
{
|
|
struct simple_xattr *new_xattr;
|
|
size_t len;
|
|
|
|
/* wrap around? */
|
|
len = sizeof(*new_xattr) + size;
|
|
if (len < sizeof(*new_xattr))
|
|
return NULL;
|
|
|
|
new_xattr = kvmalloc(len, GFP_KERNEL);
|
|
if (!new_xattr)
|
|
return NULL;
|
|
|
|
new_xattr->size = size;
|
|
memcpy(new_xattr->value, value, size);
|
|
return new_xattr;
|
|
}
|
|
|
|
/**
|
|
* rbtree_simple_xattr_cmp - compare xattr name with current rbtree xattr entry
|
|
* @key: xattr name
|
|
* @node: current node
|
|
*
|
|
* Compare the xattr name with the xattr name attached to @node in the rbtree.
|
|
*
|
|
* Return: Negative value if continuing left, positive if continuing right, 0
|
|
* if the xattr attached to @node matches @key.
|
|
*/
|
|
static int rbtree_simple_xattr_cmp(const void *key, const struct rb_node *node)
|
|
{
|
|
const char *xattr_name = key;
|
|
const struct simple_xattr *xattr;
|
|
|
|
xattr = rb_entry(node, struct simple_xattr, rb_node);
|
|
return strcmp(xattr->name, xattr_name);
|
|
}
|
|
|
|
/**
|
|
* rbtree_simple_xattr_node_cmp - compare two xattr rbtree nodes
|
|
* @new_node: new node
|
|
* @node: current node
|
|
*
|
|
* Compare the xattr attached to @new_node with the xattr attached to @node.
|
|
*
|
|
* Return: Negative value if continuing left, positive if continuing right, 0
|
|
* if the xattr attached to @new_node matches the xattr attached to @node.
|
|
*/
|
|
static int rbtree_simple_xattr_node_cmp(struct rb_node *new_node,
|
|
const struct rb_node *node)
|
|
{
|
|
struct simple_xattr *xattr;
|
|
xattr = rb_entry(new_node, struct simple_xattr, rb_node);
|
|
return rbtree_simple_xattr_cmp(xattr->name, node);
|
|
}
|
|
|
|
/**
|
|
* simple_xattr_get - get an xattr object
|
|
* @xattrs: the header of the xattr object
|
|
* @name: the name of the xattr to retrieve
|
|
* @buffer: the buffer to store the value into
|
|
* @size: the size of @buffer
|
|
*
|
|
* Try to find and retrieve the xattr object associated with @name.
|
|
* If @buffer is provided store the value of @xattr in @buffer
|
|
* otherwise just return the length. The size of @buffer is limited
|
|
* to XATTR_SIZE_MAX which currently is 65536.
|
|
*
|
|
* Return: On success the length of the xattr value is returned. On error a
|
|
* negative error code is returned.
|
|
*/
|
|
int simple_xattr_get(struct simple_xattrs *xattrs, const char *name,
|
|
void *buffer, size_t size)
|
|
{
|
|
struct simple_xattr *xattr = NULL;
|
|
struct rb_node *rbp;
|
|
int ret = -ENODATA;
|
|
|
|
read_lock(&xattrs->lock);
|
|
rbp = rb_find(name, &xattrs->rb_root, rbtree_simple_xattr_cmp);
|
|
if (rbp) {
|
|
xattr = rb_entry(rbp, struct simple_xattr, rb_node);
|
|
ret = xattr->size;
|
|
if (buffer) {
|
|
if (size < xattr->size)
|
|
ret = -ERANGE;
|
|
else
|
|
memcpy(buffer, xattr->value, xattr->size);
|
|
}
|
|
}
|
|
read_unlock(&xattrs->lock);
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* simple_xattr_set - set an xattr object
|
|
* @xattrs: the header of the xattr object
|
|
* @name: the name of the xattr to retrieve
|
|
* @value: the value to store along the xattr
|
|
* @size: the size of @value
|
|
* @flags: the flags determining how to set the xattr
|
|
* @removed_size: the size of the removed xattr
|
|
*
|
|
* Set a new xattr object.
|
|
* If @value is passed a new xattr object will be allocated. If XATTR_REPLACE
|
|
* is specified in @flags a matching xattr object for @name must already exist.
|
|
* If it does it will be replaced with the new xattr object. If it doesn't we
|
|
* fail. If XATTR_CREATE is specified and a matching xattr does already exist
|
|
* we fail. If it doesn't we create a new xattr. If @flags is zero we simply
|
|
* insert the new xattr replacing any existing one.
|
|
*
|
|
* If @value is empty and a matching xattr object is found we delete it if
|
|
* XATTR_REPLACE is specified in @flags or @flags is zero.
|
|
*
|
|
* If @value is empty and no matching xattr object for @name is found we do
|
|
* nothing if XATTR_CREATE is specified in @flags or @flags is zero. For
|
|
* XATTR_REPLACE we fail as mentioned above.
|
|
*
|
|
* Return: On success zero and on error a negative error code is returned.
|
|
*/
|
|
int simple_xattr_set(struct simple_xattrs *xattrs, const char *name,
|
|
const void *value, size_t size, int flags,
|
|
ssize_t *removed_size)
|
|
{
|
|
struct simple_xattr *xattr = NULL, *new_xattr = NULL;
|
|
struct rb_node *parent = NULL, **rbp;
|
|
int err = 0, ret;
|
|
|
|
if (removed_size)
|
|
*removed_size = -1;
|
|
|
|
/* value == NULL means remove */
|
|
if (value) {
|
|
new_xattr = simple_xattr_alloc(value, size);
|
|
if (!new_xattr)
|
|
return -ENOMEM;
|
|
|
|
new_xattr->name = kstrdup(name, GFP_KERNEL);
|
|
if (!new_xattr->name) {
|
|
free_simple_xattr(new_xattr);
|
|
return -ENOMEM;
|
|
}
|
|
}
|
|
|
|
write_lock(&xattrs->lock);
|
|
rbp = &xattrs->rb_root.rb_node;
|
|
while (*rbp) {
|
|
parent = *rbp;
|
|
ret = rbtree_simple_xattr_cmp(name, *rbp);
|
|
if (ret < 0)
|
|
rbp = &(*rbp)->rb_left;
|
|
else if (ret > 0)
|
|
rbp = &(*rbp)->rb_right;
|
|
else
|
|
xattr = rb_entry(*rbp, struct simple_xattr, rb_node);
|
|
if (xattr)
|
|
break;
|
|
}
|
|
|
|
if (xattr) {
|
|
/* Fail if XATTR_CREATE is requested and the xattr exists. */
|
|
if (flags & XATTR_CREATE) {
|
|
err = -EEXIST;
|
|
goto out_unlock;
|
|
}
|
|
|
|
if (new_xattr)
|
|
rb_replace_node(&xattr->rb_node, &new_xattr->rb_node,
|
|
&xattrs->rb_root);
|
|
else
|
|
rb_erase(&xattr->rb_node, &xattrs->rb_root);
|
|
if (!err && removed_size)
|
|
*removed_size = xattr->size;
|
|
} else {
|
|
/* Fail if XATTR_REPLACE is requested but no xattr is found. */
|
|
if (flags & XATTR_REPLACE) {
|
|
err = -ENODATA;
|
|
goto out_unlock;
|
|
}
|
|
|
|
/*
|
|
* If XATTR_CREATE or no flags are specified together with a
|
|
* new value simply insert it.
|
|
*/
|
|
if (new_xattr) {
|
|
rb_link_node(&new_xattr->rb_node, parent, rbp);
|
|
rb_insert_color(&new_xattr->rb_node, &xattrs->rb_root);
|
|
}
|
|
|
|
/*
|
|
* If XATTR_CREATE or no flags are specified and neither an
|
|
* old or new xattr exist then we don't need to do anything.
|
|
*/
|
|
}
|
|
|
|
out_unlock:
|
|
write_unlock(&xattrs->lock);
|
|
if (err)
|
|
free_simple_xattr(new_xattr);
|
|
else
|
|
free_simple_xattr(xattr);
|
|
return err;
|
|
|
|
}
|
|
|
|
static bool xattr_is_trusted(const char *name)
|
|
{
|
|
return !strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN);
|
|
}
|
|
|
|
static int xattr_list_one(char **buffer, ssize_t *remaining_size,
|
|
const char *name)
|
|
{
|
|
size_t len = strlen(name) + 1;
|
|
if (*buffer) {
|
|
if (*remaining_size < len)
|
|
return -ERANGE;
|
|
memcpy(*buffer, name, len);
|
|
*buffer += len;
|
|
}
|
|
*remaining_size -= len;
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* simple_xattr_list - list all xattr objects
|
|
* @inode: inode from which to get the xattrs
|
|
* @xattrs: the header of the xattr object
|
|
* @buffer: the buffer to store all xattrs into
|
|
* @size: the size of @buffer
|
|
*
|
|
* List all xattrs associated with @inode. If @buffer is NULL we returned
|
|
* the required size of the buffer. If @buffer is provided we store the
|
|
* xattrs value into it provided it is big enough.
|
|
*
|
|
* Note, the number of xattr names that can be listed with listxattr(2) is
|
|
* limited to XATTR_LIST_MAX aka 65536 bytes. If a larger buffer is passed
|
|
* then vfs_listxattr() caps it to XATTR_LIST_MAX and if more xattr names
|
|
* are found it will return -E2BIG.
|
|
*
|
|
* Return: On success the required size or the size of the copied xattrs is
|
|
* returned. On error a negative error code is returned.
|
|
*/
|
|
ssize_t simple_xattr_list(struct inode *inode, struct simple_xattrs *xattrs,
|
|
char *buffer, size_t size)
|
|
{
|
|
bool trusted = ns_capable_noaudit(&init_user_ns, CAP_SYS_ADMIN);
|
|
struct simple_xattr *xattr;
|
|
struct rb_node *rbp;
|
|
ssize_t remaining_size = size;
|
|
int err = 0;
|
|
|
|
#ifdef CONFIG_FS_POSIX_ACL
|
|
if (IS_POSIXACL(inode)) {
|
|
if (inode->i_acl) {
|
|
err = xattr_list_one(&buffer, &remaining_size,
|
|
XATTR_NAME_POSIX_ACL_ACCESS);
|
|
if (err)
|
|
return err;
|
|
}
|
|
if (inode->i_default_acl) {
|
|
err = xattr_list_one(&buffer, &remaining_size,
|
|
XATTR_NAME_POSIX_ACL_DEFAULT);
|
|
if (err)
|
|
return err;
|
|
}
|
|
}
|
|
#endif
|
|
|
|
read_lock(&xattrs->lock);
|
|
for (rbp = rb_first(&xattrs->rb_root); rbp; rbp = rb_next(rbp)) {
|
|
xattr = rb_entry(rbp, struct simple_xattr, rb_node);
|
|
|
|
/* skip "trusted." attributes for unprivileged callers */
|
|
if (!trusted && xattr_is_trusted(xattr->name))
|
|
continue;
|
|
|
|
err = xattr_list_one(&buffer, &remaining_size, xattr->name);
|
|
if (err)
|
|
break;
|
|
}
|
|
read_unlock(&xattrs->lock);
|
|
|
|
return err ? err : size - remaining_size;
|
|
}
|
|
|
|
/**
|
|
* rbtree_simple_xattr_less - compare two xattr rbtree nodes
|
|
* @new_node: new node
|
|
* @node: current node
|
|
*
|
|
* Compare the xattr attached to @new_node with the xattr attached to @node.
|
|
* Note that this function technically tolerates duplicate entries.
|
|
*
|
|
* Return: True if insertion point in the rbtree is found.
|
|
*/
|
|
static bool rbtree_simple_xattr_less(struct rb_node *new_node,
|
|
const struct rb_node *node)
|
|
{
|
|
return rbtree_simple_xattr_node_cmp(new_node, node) < 0;
|
|
}
|
|
|
|
/**
|
|
* simple_xattr_add - add xattr objects
|
|
* @xattrs: the header of the xattr object
|
|
* @new_xattr: the xattr object to add
|
|
*
|
|
* Add an xattr object to @xattrs. This assumes no replacement or removal
|
|
* of matching xattrs is wanted. Should only be called during inode
|
|
* initialization when a few distinct initial xattrs are supposed to be set.
|
|
*/
|
|
void simple_xattr_add(struct simple_xattrs *xattrs,
|
|
struct simple_xattr *new_xattr)
|
|
{
|
|
write_lock(&xattrs->lock);
|
|
rb_add(&new_xattr->rb_node, &xattrs->rb_root, rbtree_simple_xattr_less);
|
|
write_unlock(&xattrs->lock);
|
|
}
|
|
|
|
/**
|
|
* simple_xattrs_init - initialize new xattr header
|
|
* @xattrs: header to initialize
|
|
*
|
|
* Initialize relevant fields of a an xattr header.
|
|
*/
|
|
void simple_xattrs_init(struct simple_xattrs *xattrs)
|
|
{
|
|
xattrs->rb_root = RB_ROOT;
|
|
rwlock_init(&xattrs->lock);
|
|
}
|
|
|
|
/**
|
|
* simple_xattrs_free - free xattrs
|
|
* @xattrs: xattr header whose xattrs to destroy
|
|
*
|
|
* Destroy all xattrs in @xattr. When this is called no one can hold a
|
|
* reference to any of the xattrs anymore.
|
|
*/
|
|
void simple_xattrs_free(struct simple_xattrs *xattrs)
|
|
{
|
|
struct rb_node *rbp;
|
|
|
|
rbp = rb_first(&xattrs->rb_root);
|
|
while (rbp) {
|
|
struct simple_xattr *xattr;
|
|
struct rb_node *rbp_next;
|
|
|
|
rbp_next = rb_next(rbp);
|
|
xattr = rb_entry(rbp, struct simple_xattr, rb_node);
|
|
rb_erase(&xattr->rb_node, &xattrs->rb_root);
|
|
free_simple_xattr(xattr);
|
|
rbp = rbp_next;
|
|
}
|
|
}
|