Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

1 files changed, 1303 insertions, 0 deletions

diff --git a/fs/posix_acl.c b/fs/posix_acl.c
new file mode 100644
index 000000000..18b302f94
--- /dev/null
+++ b/fs/posix_acl.c
@@ -0,0 +1,1303 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2002,2003 by Andreas Gruenbacher <a.gruenbacher@computer.org>
+ *
+ * Fixes from William Schumacher incorporated on 15 March 2001.
+ *    (Reported by Charles Bertsch, <CBertsch@microtest.com>).
+ */
+
+/*
+ *  This file contains generic functions for manipulating
+ *  POSIX 1003.1e draft standard 17 ACLs.
+ */
+
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/atomic.h>
+#include <linux/fs.h>
+#include <linux/sched.h>
+#include <linux/cred.h>
+#include <linux/posix_acl.h>
+#include <linux/posix_acl_xattr.h>
+#include <linux/xattr.h>
+#include <linux/export.h>
+#include <linux/user_namespace.h>
+#include <linux/namei.h>
+#include <linux/mnt_idmapping.h>
+#include <linux/iversion.h>
+#include <linux/security.h>
+#include <linux/fsnotify.h>
+#include <linux/filelock.h>
+
+#include "internal.h"
+
+static struct posix_acl **acl_by_type(struct inode *inode, int type)
+{
+	switch (type) {
+	case ACL_TYPE_ACCESS:
+		return &inode->i_acl;
+	case ACL_TYPE_DEFAULT:
+		return &inode->i_default_acl;
+	default:
+		BUG();
+	}
+}
+
+struct posix_acl *get_cached_acl(struct inode *inode, int type)
+{
+	struct posix_acl **p = acl_by_type(inode, type);
+	struct posix_acl *acl;
+
+	for (;;) {
+		rcu_read_lock();
+		acl = rcu_dereference(*p);
+		if (!acl || is_uncached_acl(acl) ||
+		    refcount_inc_not_zero(&acl->a_refcount))
+			break;
+		rcu_read_unlock();
+		cpu_relax();
+	}
+	rcu_read_unlock();
+	return acl;
+}
+EXPORT_SYMBOL(get_cached_acl);
+
+struct posix_acl *get_cached_acl_rcu(struct inode *inode, int type)
+{
+	struct posix_acl *acl = rcu_dereference(*acl_by_type(inode, type));
+
+	if (acl == ACL_DONT_CACHE) {
+		struct posix_acl *ret;
+
+		ret = inode->i_op->get_inode_acl(inode, type, LOOKUP_RCU);
+		if (!IS_ERR(ret))
+			acl = ret;
+	}
+
+	return acl;
+}
+EXPORT_SYMBOL(get_cached_acl_rcu);
+
+void set_cached_acl(struct inode *inode, int type, struct posix_acl *acl)
+{
+	struct posix_acl **p = acl_by_type(inode, type);
+	struct posix_acl *old;
+
+	old = xchg(p, posix_acl_dup(acl));
+	if (!is_uncached_acl(old))
+		posix_acl_release(old);
+}
+EXPORT_SYMBOL(set_cached_acl);
+
+static void __forget_cached_acl(struct posix_acl **p)
+{
+	struct posix_acl *old;
+
+	/*
+	 * ACL_DONT_CACHE is expected to be a "const" value and xchg it with
+	 * ACL_NOT_CACHED would enable acl caching for the inode -
+	 * clearly not what the caller has intended.
+	 */
+	if (READ_ONCE(*p) == ACL_DONT_CACHE)
+		return;
+	old = xchg(p, ACL_NOT_CACHED);
+	if (!is_uncached_acl(old))
+		posix_acl_release(old);
+}
+
+void forget_cached_acl(struct inode *inode, int type)
+{
+	__forget_cached_acl(acl_by_type(inode, type));
+}
+EXPORT_SYMBOL(forget_cached_acl);
+
+void forget_all_cached_acls(struct inode *inode)
+{
+	__forget_cached_acl(&inode->i_acl);
+	__forget_cached_acl(&inode->i_default_acl);
+}
+EXPORT_SYMBOL(forget_all_cached_acls);
+
+static struct posix_acl *__get_acl(struct mnt_idmap *idmap,
+				   struct dentry *dentry, struct inode *inode,
+				   int type)
+{
+	struct posix_acl *sentinel;
+	struct posix_acl **p;
+	struct posix_acl *acl;
+
+	/*
+	 * The sentinel is used to detect when another operation like
+	 * set_cached_acl() or forget_cached_acl() races with get_inode_acl().
+	 * It is guaranteed that is_uncached_acl(sentinel) is true.
+	 */
+
+	acl = get_cached_acl(inode, type);
+	if (!is_uncached_acl(acl))
+		return acl;
+
+	if (!IS_POSIXACL(inode))
+		return NULL;
+
+	sentinel = uncached_acl_sentinel(current);
+	p = acl_by_type(inode, type);
+
+	/*
+	 * If the ACL isn't being read yet, set our sentinel.  Otherwise, the
+	 * current value of the ACL will not be ACL_NOT_CACHED and so our own
+	 * sentinel will not be set; another task will update the cache.  We
+	 * could wait for that other task to complete its job, but it's easier
+	 * to just call ->get_inode_acl to fetch the ACL ourself.  (This is
+	 * going to be an unlikely race.)
+	 */
+	cmpxchg(p, ACL_NOT_CACHED, sentinel);
+
+	/*
+	 * Normally, the ACL returned by ->get{_inode}_acl will be cached.
+	 * A filesystem can prevent that by calling
+	 * forget_cached_acl(inode, type) in ->get{_inode}_acl.
+	 *
+	 * If the filesystem doesn't have a get{_inode}_ acl() function at all,
+	 * we'll just create the negative cache entry.
+	 */
+	if (dentry && inode->i_op->get_acl) {
+		acl = inode->i_op->get_acl(idmap, dentry, type);
+	} else if (inode->i_op->get_inode_acl) {
+		acl = inode->i_op->get_inode_acl(inode, type, false);
+	} else {
+		set_cached_acl(inode, type, NULL);
+		return NULL;
+	}
+	if (IS_ERR(acl)) {
+		/*
+		 * Remove our sentinel so that we don't block future attempts
+		 * to cache the ACL.
+		 */
+		cmpxchg(p, sentinel, ACL_NOT_CACHED);
+		return acl;
+	}
+
+	/*
+	 * Cache the result, but only if our sentinel is still in place.
+	 */
+	posix_acl_dup(acl);
+	if (unlikely(!try_cmpxchg(p, &sentinel, acl)))
+		posix_acl_release(acl);
+	return acl;
+}
+
+struct posix_acl *get_inode_acl(struct inode *inode, int type)
+{
+	return __get_acl(&nop_mnt_idmap, NULL, inode, type);
+}
+EXPORT_SYMBOL(get_inode_acl);
+
+/*
+ * Init a fresh posix_acl
+ */
+void
+posix_acl_init(struct posix_acl *acl, int count)
+{
+	refcount_set(&acl->a_refcount, 1);
+	acl->a_count = count;
+}
+EXPORT_SYMBOL(posix_acl_init);
+
+/*
+ * Allocate a new ACL with the specified number of entries.
+ */
+struct posix_acl *
+posix_acl_alloc(unsigned int count, gfp_t flags)
+{
+	struct posix_acl *acl;
+
+	acl = kmalloc_flex(*acl, a_entries, count, flags);
+	if (acl)
+		posix_acl_init(acl, count);
+	return acl;
+}
+EXPORT_SYMBOL(posix_acl_alloc);
+
+/*
+ * Clone an ACL.
+ */
+struct posix_acl *
+posix_acl_clone(const struct posix_acl *acl, gfp_t flags)
+{
+	struct posix_acl *clone = NULL;
+
+	if (acl) {
+		clone = kmemdup(acl, struct_size(acl, a_entries, acl->a_count),
+				flags);
+		if (clone)
+			refcount_set(&clone->a_refcount, 1);
+	}
+	return clone;
+}
+EXPORT_SYMBOL_GPL(posix_acl_clone);
+
+/*
+ * Check if an acl is valid. Returns 0 if it is, or -E... otherwise.
+ */
+int
+posix_acl_valid(struct user_namespace *user_ns, const struct posix_acl *acl)
+{
+	const struct posix_acl_entry *pa, *pe;
+	int state = ACL_USER_OBJ;
+	int needs_mask = 0;
+
+	FOREACH_ACL_ENTRY(pa, acl, pe) {
+		if (pa->e_perm & ~(ACL_READ|ACL_WRITE|ACL_EXECUTE))
+			return -EINVAL;
+		switch (pa->e_tag) {
+			case ACL_USER_OBJ:
+				if (state == ACL_USER_OBJ) {
+					state = ACL_USER;
+					break;
+				}
+				return -EINVAL;
+
+			case ACL_USER:
+				if (state != ACL_USER)
+					return -EINVAL;
+				if (!kuid_has_mapping(user_ns, pa->e_uid))
+					return -EINVAL;
+				needs_mask = 1;
+				break;
+
+			case ACL_GROUP_OBJ:
+				if (state == ACL_USER) {
+					state = ACL_GROUP;
+					break;
+				}
+				return -EINVAL;
+
+			case ACL_GROUP:
+				if (state != ACL_GROUP)
+					return -EINVAL;
+				if (!kgid_has_mapping(user_ns, pa->e_gid))
+					return -EINVAL;
+				needs_mask = 1;
+				break;
+
+			case ACL_MASK:
+				if (state != ACL_GROUP)
+					return -EINVAL;
+				state = ACL_OTHER;
+				break;
+
+			case ACL_OTHER:
+				if (state == ACL_OTHER ||
+				    (state == ACL_GROUP && !needs_mask)) {
+					state = 0;
+					break;
+				}
+				return -EINVAL;
+
+			default:
+				return -EINVAL;
+		}
+	}
+	if (state == 0)
+		return 0;
+	return -EINVAL;
+}
+EXPORT_SYMBOL(posix_acl_valid);
+
+/*
+ * Returns 0 if the acl can be exactly represented in the traditional
+ * file mode permission bits, or else 1. Returns -E... on error.
+ */
+int
+posix_acl_equiv_mode(const struct posix_acl *acl, umode_t *mode_p)
+{
+	const struct posix_acl_entry *pa, *pe;
+	umode_t mode = 0;
+	int not_equiv = 0;
+
+	/*
+	 * A null ACL can always be presented as mode bits.
+	 */
+	if (!acl)
+		return 0;
+
+	FOREACH_ACL_ENTRY(pa, acl, pe) {
+		switch (pa->e_tag) {
+			case ACL_USER_OBJ:
+				mode |= (pa->e_perm & S_IRWXO) << 6;
+				break;
+			case ACL_GROUP_OBJ:
+				mode |= (pa->e_perm & S_IRWXO) << 3;
+				break;
+			case ACL_OTHER:
+				mode |= pa->e_perm & S_IRWXO;
+				break;
+			case ACL_MASK:
+				mode = (mode & ~S_IRWXG) |
+				       ((pa->e_perm & S_IRWXO) << 3);
+				not_equiv = 1;
+				break;
+			case ACL_USER:
+			case ACL_GROUP:
+				not_equiv = 1;
+				break;
+			default:
+				return -EINVAL;
+		}
+	}
+        if (mode_p)
+                *mode_p = (*mode_p & ~S_IRWXUGO) | mode;
+        return not_equiv;
+}
+EXPORT_SYMBOL(posix_acl_equiv_mode);
+
+/*
+ * Create an ACL representing the file mode permission bits of an inode.
+ */
+struct posix_acl *
+posix_acl_from_mode(umode_t mode, gfp_t flags)
+{
+	struct posix_acl *acl = posix_acl_alloc(3, flags);
+	if (!acl)
+		return ERR_PTR(-ENOMEM);
+
+	acl->a_entries[0].e_tag  = ACL_USER_OBJ;
+	acl->a_entries[0].e_perm = (mode & S_IRWXU) >> 6;
+
+	acl->a_entries[1].e_tag  = ACL_GROUP_OBJ;
+	acl->a_entries[1].e_perm = (mode & S_IRWXG) >> 3;
+
+	acl->a_entries[2].e_tag  = ACL_OTHER;
+	acl->a_entries[2].e_perm = (mode & S_IRWXO);
+	return acl;
+}
+EXPORT_SYMBOL(posix_acl_from_mode);
+
+/*
+ * Return 0 if current is granted want access to the inode
+ * by the acl. Returns -E... otherwise.
+ */
+int
+posix_acl_permission(struct mnt_idmap *idmap, struct inode *inode,
+		     const struct posix_acl *acl, int want)
+{
+	const struct posix_acl_entry *pa, *pe, *mask_obj;
+	struct user_namespace *fs_userns = i_user_ns(inode);
+	int found = 0;
+	vfsuid_t vfsuid;
+	vfsgid_t vfsgid;
+
+	want &= MAY_READ | MAY_WRITE | MAY_EXEC;
+
+	FOREACH_ACL_ENTRY(pa, acl, pe) {
+                switch(pa->e_tag) {
+                        case ACL_USER_OBJ:
+				/* (May have been checked already) */
+				vfsuid = i_uid_into_vfsuid(idmap, inode);
+				if (vfsuid_eq_kuid(vfsuid, current_fsuid()))
+                                        goto check_perm;
+                                break;
+                        case ACL_USER:
+				vfsuid = make_vfsuid(idmap, fs_userns,
+						     pa->e_uid);
+				if (vfsuid_eq_kuid(vfsuid, current_fsuid()))
+                                        goto mask;
+				break;
+                        case ACL_GROUP_OBJ:
+				vfsgid = i_gid_into_vfsgid(idmap, inode);
+				if (vfsgid_in_group_p(vfsgid)) {
+					found = 1;
+					if ((pa->e_perm & want) == want)
+						goto mask;
+                                }
+				break;
+                        case ACL_GROUP:
+				vfsgid = make_vfsgid(idmap, fs_userns,
+						     pa->e_gid);
+				if (vfsgid_in_group_p(vfsgid)) {
+					found = 1;
+					if ((pa->e_perm & want) == want)
+						goto mask;
+                                }
+                                break;
+                        case ACL_MASK:
+                                break;
+                        case ACL_OTHER:
+				if (found)
+					return -EACCES;
+				else
+					goto check_perm;
+			default:
+				return -EIO;
+                }
+        }
+	return -EIO;
+
+mask:
+	for (mask_obj = pa+1; mask_obj != pe; mask_obj++) {
+		if (mask_obj->e_tag == ACL_MASK) {
+			if ((pa->e_perm & mask_obj->e_perm & want) == want)
+				return 0;
+			return -EACCES;
+		}
+	}
+
+check_perm:
+	if ((pa->e_perm & want) == want)
+		return 0;
+	return -EACCES;
+}
+
+/*
+ * Modify acl when creating a new inode. The caller must ensure the acl is
+ * only referenced once.
+ *
+ * mode_p initially must contain the mode parameter to the open() / creat()
+ * system calls. All permissions that are not granted by the acl are removed.
+ * The permissions in the acl are changed to reflect the mode_p parameter.
+ */
+static int posix_acl_create_masq(struct posix_acl *acl, umode_t *mode_p)
+{
+	struct posix_acl_entry *pa, *pe;
+	struct posix_acl_entry *group_obj = NULL, *mask_obj = NULL;
+	umode_t mode = *mode_p;
+	int not_equiv = 0;
+
+	/* assert(atomic_read(acl->a_refcount) == 1); */
+
+	FOREACH_ACL_ENTRY(pa, acl, pe) {
+                switch(pa->e_tag) {
+                        case ACL_USER_OBJ:
+				pa->e_perm &= (mode >> 6) | ~S_IRWXO;
+				mode &= (pa->e_perm << 6) | ~S_IRWXU;
+				break;
+
+			case ACL_USER:
+			case ACL_GROUP:
+				not_equiv = 1;
+				break;
+
+                        case ACL_GROUP_OBJ:
+				group_obj = pa;
+                                break;
+
+                        case ACL_OTHER:
+				pa->e_perm &= mode | ~S_IRWXO;
+				mode &= pa->e_perm | ~S_IRWXO;
+                                break;
+
+                        case ACL_MASK:
+				mask_obj = pa;
+				not_equiv = 1;
+                                break;
+
+			default:
+				return -EIO;
+                }
+        }
+
+	if (mask_obj) {
+		mask_obj->e_perm &= (mode >> 3) | ~S_IRWXO;
+		mode &= (mask_obj->e_perm << 3) | ~S_IRWXG;
+	} else {
+		if (!group_obj)
+			return -EIO;
+		group_obj->e_perm &= (mode >> 3) | ~S_IRWXO;
+		mode &= (group_obj->e_perm << 3) | ~S_IRWXG;
+	}
+
+	*mode_p = (*mode_p & ~S_IRWXUGO) | mode;
+        return not_equiv;
+}
+
+/*
+ * Modify the ACL for the chmod syscall.
+ */
+static int __posix_acl_chmod_masq(struct posix_acl *acl, umode_t mode)
+{
+	struct posix_acl_entry *group_obj = NULL, *mask_obj = NULL;
+	struct posix_acl_entry *pa, *pe;
+
+	/* assert(atomic_read(acl->a_refcount) == 1); */
+
+	FOREACH_ACL_ENTRY(pa, acl, pe) {
+		switch(pa->e_tag) {
+			case ACL_USER_OBJ:
+				pa->e_perm = (mode & S_IRWXU) >> 6;
+				break;
+
+			case ACL_USER:
+			case ACL_GROUP:
+				break;
+
+			case ACL_GROUP_OBJ:
+				group_obj = pa;
+				break;
+
+			case ACL_MASK:
+				mask_obj = pa;
+				break;
+
+			case ACL_OTHER:
+				pa->e_perm = (mode & S_IRWXO);
+				break;
+
+			default:
+				return -EIO;
+		}
+	}
+
+	if (mask_obj) {
+		mask_obj->e_perm = (mode & S_IRWXG) >> 3;
+	} else {
+		if (!group_obj)
+			return -EIO;
+		group_obj->e_perm = (mode & S_IRWXG) >> 3;
+	}
+
+	return 0;
+}
+
+int
+__posix_acl_create(struct posix_acl **acl, gfp_t gfp, umode_t *mode_p)
+{
+	struct posix_acl *clone = posix_acl_clone(*acl, gfp);
+	int err = -ENOMEM;
+	if (clone) {
+		err = posix_acl_create_masq(clone, mode_p);
+		if (err < 0) {
+			posix_acl_release(clone);
+			clone = NULL;
+		}
+	}
+	posix_acl_release(*acl);
+	*acl = clone;
+	return err;
+}
+EXPORT_SYMBOL(__posix_acl_create);
+
+int
+__posix_acl_chmod(struct posix_acl **acl, gfp_t gfp, umode_t mode)
+{
+	struct posix_acl *clone = posix_acl_clone(*acl, gfp);
+	int err = -ENOMEM;
+	if (clone) {
+		err = __posix_acl_chmod_masq(clone, mode);
+		if (err) {
+			posix_acl_release(clone);
+			clone = NULL;
+		}
+	}
+	posix_acl_release(*acl);
+	*acl = clone;
+	return err;
+}
+EXPORT_SYMBOL(__posix_acl_chmod);
+
+/**
+ * posix_acl_chmod - chmod a posix acl
+ *
+ * @idmap:	idmap of the mount @inode was found from
+ * @dentry:	dentry to check permissions on
+ * @mode:	the new mode of @inode
+ *
+ * If the dentry has been found through an idmapped mount the idmap of
+ * the vfsmount must be passed through @idmap. This function will then
+ * take care to map the inode according to @idmap before checking
+ * permissions. On non-idmapped mounts or if permission checking is to be
+ * performed on the raw inode simply pass @nop_mnt_idmap.
+ */
+int
+ posix_acl_chmod(struct mnt_idmap *idmap, struct dentry *dentry,
+		    umode_t mode)
+{
+	struct inode *inode = d_inode(dentry);
+	struct posix_acl *acl;
+	int ret = 0;
+
+	if (!IS_POSIXACL(inode))
+		return 0;
+	if (!inode->i_op->set_acl)
+		return -EOPNOTSUPP;
+
+	acl = get_inode_acl(inode, ACL_TYPE_ACCESS);
+	if (IS_ERR_OR_NULL(acl)) {
+		if (acl == ERR_PTR(-EOPNOTSUPP))
+			return 0;
+		return PTR_ERR(acl);
+	}
+
+	ret = __posix_acl_chmod(&acl, GFP_KERNEL, mode);
+	if (ret)
+		return ret;
+	ret = inode->i_op->set_acl(idmap, dentry, acl, ACL_TYPE_ACCESS);
+	posix_acl_release(acl);
+	return ret;
+}
+EXPORT_SYMBOL(posix_acl_chmod);
+
+int
+posix_acl_create(struct inode *dir, umode_t *mode,
+		struct posix_acl **default_acl, struct posix_acl **acl)
+{
+	struct posix_acl *p;
+	struct posix_acl *clone;
+	int ret;
+
+	*acl = NULL;
+	*default_acl = NULL;
+
+	if (S_ISLNK(*mode) || !IS_POSIXACL(dir))
+		return 0;
+
+	p = get_inode_acl(dir, ACL_TYPE_DEFAULT);
+	if (!p || p == ERR_PTR(-EOPNOTSUPP)) {
+		*mode &= ~current_umask();
+		return 0;
+	}
+	if (IS_ERR(p))
+		return PTR_ERR(p);
+
+	ret = -ENOMEM;
+	clone = posix_acl_clone(p, GFP_NOFS);
+	if (!clone)
+		goto err_release;
+
+	ret = posix_acl_create_masq(clone, mode);
+	if (ret < 0)
+		goto err_release_clone;
+
+	if (ret == 0)
+		posix_acl_release(clone);
+	else
+		*acl = clone;
+
+	if (!S_ISDIR(*mode))
+		posix_acl_release(p);
+	else
+		*default_acl = p;
+
+	return 0;
+
+err_release_clone:
+	posix_acl_release(clone);
+err_release:
+	posix_acl_release(p);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(posix_acl_create);
+
+/**
+ * posix_acl_update_mode  -  update mode in set_acl
+ * @idmap:	idmap of the mount @inode was found from
+ * @inode:	target inode
+ * @mode_p:	mode (pointer) for update
+ * @acl:	acl pointer
+ *
+ * Update the file mode when setting an ACL: compute the new file permission
+ * bits based on the ACL.  In addition, if the ACL is equivalent to the new
+ * file mode, set *@acl to NULL to indicate that no ACL should be set.
+ *
+ * As with chmod, clear the setgid bit if the caller is not in the owning group
+ * or capable of CAP_FSETID (see inode_change_ok).
+ *
+ * If the inode has been found through an idmapped mount the idmap of
+ * the vfsmount must be passed through @idmap. This function will then
+ * take care to map the inode according to @idmap before checking
+ * permissions. On non-idmapped mounts or if permission checking is to be
+ * performed on the raw inode simply pass @nop_mnt_idmap.
+ *
+ * Called from set_acl inode operations.
+ */
+int posix_acl_update_mode(struct mnt_idmap *idmap,
+			  struct inode *inode, umode_t *mode_p,
+			  struct posix_acl **acl)
+{
+	umode_t mode = inode->i_mode;
+	int error;
+
+	error = posix_acl_equiv_mode(*acl, &mode);
+	if (error < 0)
+		return error;
+	if (error == 0)
+		*acl = NULL;
+	if (!in_group_or_capable(idmap, inode,
+				 i_gid_into_vfsgid(idmap, inode)))
+		mode &= ~S_ISGID;
+	*mode_p = mode;
+	return 0;
+}
+EXPORT_SYMBOL(posix_acl_update_mode);
+
+/*
+ * Fix up the uids and gids in posix acl extended attributes in place.
+ */
+static int posix_acl_fix_xattr_common(const void *value, size_t size)
+{
+	const struct posix_acl_xattr_header *header = value;
+	int count;
+
+	if (!header)
+		return -EINVAL;
+	if (size < sizeof(struct posix_acl_xattr_header))
+		return -EINVAL;
+	if (header->a_version != cpu_to_le32(POSIX_ACL_XATTR_VERSION))
+		return -EOPNOTSUPP;
+
+	count = posix_acl_xattr_count(size);
+	if (count < 0)
+		return -EINVAL;
+
+	return count;
+}
+
+/**
+ * posix_acl_from_xattr - convert POSIX ACLs from backing store to VFS format
+ * @userns: the filesystem's idmapping
+ * @value: the uapi representation of POSIX ACLs
+ * @size: the size of @void
+ *
+ * Filesystems that store POSIX ACLs in the unaltered uapi format should use
+ * posix_acl_from_xattr() when reading them from the backing store and
+ * converting them into the struct posix_acl VFS format. The helper is
+ * specifically intended to be called from the acl inode operation.
+ *
+ * The posix_acl_from_xattr() function will map the raw {g,u}id values stored
+ * in ACL_{GROUP,USER} entries into idmapping in @userns.
+ *
+ * Note that posix_acl_from_xattr() does not take idmapped mounts into account.
+ * If it did it calling it from the get acl inode operation would return POSIX
+ * ACLs mapped according to an idmapped mount which would mean that the value
+ * couldn't be cached for the filesystem. Idmapped mounts are taken into
+ * account on the fly during permission checking or right at the VFS -
+ * userspace boundary before reporting them to the user.
+ *
+ * Return: Allocated struct posix_acl on success, NULL for a valid header but
+ *         without actual POSIX ACL entries, or ERR_PTR() encoded error code.
+ */
+struct posix_acl *posix_acl_from_xattr(struct user_namespace *userns,
+				       const void *value, size_t size)
+{
+	const struct posix_acl_xattr_header *header = value;
+	const struct posix_acl_xattr_entry *entry = (const void *)(header + 1), *end;
+	int count;
+	struct posix_acl *acl;
+	struct posix_acl_entry *acl_e;
+
+	count = posix_acl_fix_xattr_common(value, size);
+	if (count < 0)
+		return ERR_PTR(count);
+	if (count == 0)
+		return NULL;
+
+	acl = posix_acl_alloc(count, GFP_NOFS);
+	if (!acl)
+		return ERR_PTR(-ENOMEM);
+	acl_e = acl->a_entries;
+
+	for (end = entry + count; entry != end; acl_e++, entry++) {
+		acl_e->e_tag  = le16_to_cpu(entry->e_tag);
+		acl_e->e_perm = le16_to_cpu(entry->e_perm);
+
+		switch(acl_e->e_tag) {
+			case ACL_USER_OBJ:
+			case ACL_GROUP_OBJ:
+			case ACL_MASK:
+			case ACL_OTHER:
+				break;
+
+			case ACL_USER:
+				acl_e->e_uid = make_kuid(userns,
+						le32_to_cpu(entry->e_id));
+				if (!uid_valid(acl_e->e_uid))
+					goto fail;
+				break;
+			case ACL_GROUP:
+				acl_e->e_gid = make_kgid(userns,
+						le32_to_cpu(entry->e_id));
+				if (!gid_valid(acl_e->e_gid))
+					goto fail;
+				break;
+
+			default:
+				goto fail;
+		}
+	}
+	return acl;
+
+fail:
+	posix_acl_release(acl);
+	return ERR_PTR(-EINVAL);
+}
+EXPORT_SYMBOL (posix_acl_from_xattr);
+
+/*
+ * Convert from in-memory to extended attribute representation.
+ */
+void *
+posix_acl_to_xattr(struct user_namespace *user_ns, const struct posix_acl *acl,
+		   size_t *sizep, gfp_t gfp)
+{
+	struct posix_acl_xattr_header *ext_acl;
+	struct posix_acl_xattr_entry *ext_entry;
+	size_t size;
+	int n;
+
+	size = posix_acl_xattr_size(acl->a_count);
+	ext_acl = kmalloc(size, gfp);
+	if (!ext_acl)
+		return NULL;
+
+	ext_entry = (void *)(ext_acl + 1);
+	ext_acl->a_version = cpu_to_le32(POSIX_ACL_XATTR_VERSION);
+
+	for (n=0; n < acl->a_count; n++, ext_entry++) {
+		const struct posix_acl_entry *acl_e = &acl->a_entries[n];
+		ext_entry->e_tag  = cpu_to_le16(acl_e->e_tag);
+		ext_entry->e_perm = cpu_to_le16(acl_e->e_perm);
+		switch(acl_e->e_tag) {
+		case ACL_USER:
+			ext_entry->e_id =
+				cpu_to_le32(from_kuid(user_ns, acl_e->e_uid));
+			break;
+		case ACL_GROUP:
+			ext_entry->e_id =
+				cpu_to_le32(from_kgid(user_ns, acl_e->e_gid));
+			break;
+		default:
+			ext_entry->e_id = cpu_to_le32(ACL_UNDEFINED_ID);
+			break;
+		}
+	}
+	*sizep = size;
+	return ext_acl;
+}
+EXPORT_SYMBOL (posix_acl_to_xattr);
+
+/**
+ * vfs_posix_acl_to_xattr - convert from kernel to userspace representation
+ * @idmap: idmap of the mount
+ * @inode: inode the posix acls are set on
+ * @acl: the posix acls as represented by the vfs
+ * @buffer: the buffer into which to convert @acl
+ * @size: size of @buffer
+ *
+ * This converts @acl from the VFS representation in the filesystem idmapping
+ * to the uapi form reportable to userspace. And mount and caller idmappings
+ * are handled appropriately.
+ *
+ * Return: On success, the size of the stored uapi posix acls, on error a
+ * negative errno.
+ */
+static ssize_t vfs_posix_acl_to_xattr(struct mnt_idmap *idmap,
+				      struct inode *inode,
+				      const struct posix_acl *acl, void *buffer,
+				      size_t size)
+
+{
+	struct posix_acl_xattr_header *ext_acl = buffer;
+	struct posix_acl_xattr_entry *ext_entry;
+	struct user_namespace *fs_userns, *caller_userns;
+	ssize_t real_size, n;
+	vfsuid_t vfsuid;
+	vfsgid_t vfsgid;
+
+	real_size = posix_acl_xattr_size(acl->a_count);
+	if (!buffer)
+		return real_size;
+	if (real_size > size)
+		return -ERANGE;
+
+	ext_entry = (void *)(ext_acl + 1);
+	ext_acl->a_version = cpu_to_le32(POSIX_ACL_XATTR_VERSION);
+
+	fs_userns = i_user_ns(inode);
+	caller_userns = current_user_ns();
+	for (n=0; n < acl->a_count; n++, ext_entry++) {
+		const struct posix_acl_entry *acl_e = &acl->a_entries[n];
+		ext_entry->e_tag  = cpu_to_le16(acl_e->e_tag);
+		ext_entry->e_perm = cpu_to_le16(acl_e->e_perm);
+		switch(acl_e->e_tag) {
+		case ACL_USER:
+			vfsuid = make_vfsuid(idmap, fs_userns, acl_e->e_uid);
+			ext_entry->e_id = cpu_to_le32(from_kuid(
+				caller_userns, vfsuid_into_kuid(vfsuid)));
+			break;
+		case ACL_GROUP:
+			vfsgid = make_vfsgid(idmap, fs_userns, acl_e->e_gid);
+			ext_entry->e_id = cpu_to_le32(from_kgid(
+				caller_userns, vfsgid_into_kgid(vfsgid)));
+			break;
+		default:
+			ext_entry->e_id = cpu_to_le32(ACL_UNDEFINED_ID);
+			break;
+		}
+	}
+	return real_size;
+}
+
+int
+set_posix_acl(struct mnt_idmap *idmap, struct dentry *dentry,
+	      int type, struct posix_acl *acl)
+{
+	struct inode *inode = d_inode(dentry);
+
+	if (!IS_POSIXACL(inode))
+		return -EOPNOTSUPP;
+	if (!inode->i_op->set_acl)
+		return -EOPNOTSUPP;
+
+	if (type == ACL_TYPE_DEFAULT && !S_ISDIR(inode->i_mode))
+		return acl ? -EACCES : 0;
+	if (!inode_owner_or_capable(idmap, inode))
+		return -EPERM;
+
+	if (acl) {
+		int ret = posix_acl_valid(inode->i_sb->s_user_ns, acl);
+		if (ret)
+			return ret;
+	}
+	return inode->i_op->set_acl(idmap, dentry, acl, type);
+}
+EXPORT_SYMBOL(set_posix_acl);
+
+int posix_acl_listxattr(struct inode *inode, char **buffer,
+			ssize_t *remaining_size)
+{
+	int err;
+
+	if (!IS_POSIXACL(inode))
+		return 0;
+
+	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;
+	}
+
+	return 0;
+}
+
+static bool
+posix_acl_xattr_list(struct dentry *dentry)
+{
+	return IS_POSIXACL(d_backing_inode(dentry));
+}
+
+/*
+ * nop_posix_acl_access - legacy xattr handler for access POSIX ACLs
+ *
+ * This is the legacy POSIX ACL access xattr handler. It is used by some
+ * filesystems to implement their ->listxattr() inode operation. New code
+ * should never use them.
+ */
+const struct xattr_handler nop_posix_acl_access = {
+	.name = XATTR_NAME_POSIX_ACL_ACCESS,
+	.list = posix_acl_xattr_list,
+};
+EXPORT_SYMBOL_GPL(nop_posix_acl_access);
+
+/*
+ * nop_posix_acl_default - legacy xattr handler for default POSIX ACLs
+ *
+ * This is the legacy POSIX ACL default xattr handler. It is used by some
+ * filesystems to implement their ->listxattr() inode operation. New code
+ * should never use them.
+ */
+const struct xattr_handler nop_posix_acl_default = {
+	.name = XATTR_NAME_POSIX_ACL_DEFAULT,
+	.list = posix_acl_xattr_list,
+};
+EXPORT_SYMBOL_GPL(nop_posix_acl_default);
+
+int simple_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
+		   struct posix_acl *acl, int type)
+{
+	int error;
+	struct inode *inode = d_inode(dentry);
+
+	if (type == ACL_TYPE_ACCESS) {
+		error = posix_acl_update_mode(idmap, inode,
+				&inode->i_mode, &acl);
+		if (error)
+			return error;
+	}
+
+	inode_set_ctime_current(inode);
+	if (IS_I_VERSION(inode))
+		inode_inc_iversion(inode);
+	set_cached_acl(inode, type, acl);
+	return 0;
+}
+
+int simple_acl_create(struct inode *dir, struct inode *inode)
+{
+	struct posix_acl *default_acl, *acl;
+	int error;
+
+	error = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl);
+	if (error)
+		return error;
+
+	set_cached_acl(inode, ACL_TYPE_DEFAULT, default_acl);
+	set_cached_acl(inode, ACL_TYPE_ACCESS, acl);
+
+	if (default_acl)
+		posix_acl_release(default_acl);
+	if (acl)
+		posix_acl_release(acl);
+	return 0;
+}
+
+static int vfs_set_acl_idmapped_mnt(struct mnt_idmap *idmap,
+				    struct user_namespace *fs_userns,
+				    struct posix_acl *acl)
+{
+	for (int n = 0; n < acl->a_count; n++) {
+		struct posix_acl_entry *acl_e = &acl->a_entries[n];
+
+		switch (acl_e->e_tag) {
+		case ACL_USER:
+			acl_e->e_uid = from_vfsuid(idmap, fs_userns,
+						   VFSUIDT_INIT(acl_e->e_uid));
+			break;
+		case ACL_GROUP:
+			acl_e->e_gid = from_vfsgid(idmap, fs_userns,
+						   VFSGIDT_INIT(acl_e->e_gid));
+			break;
+		}
+	}
+
+	return 0;
+}
+
+/**
+ * vfs_set_acl - set posix acls
+ * @idmap: idmap of the mount
+ * @dentry: the dentry based on which to set the posix acls
+ * @acl_name: the name of the posix acl
+ * @kacl: the posix acls in the appropriate VFS format
+ *
+ * This function sets @kacl. The caller must all posix_acl_release() on @kacl
+ * afterwards.
+ *
+ * Return: On success 0, on error negative errno.
+ */
+int vfs_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
+		const char *acl_name, struct posix_acl *kacl)
+{
+	int acl_type;
+	int error;
+	struct inode *inode = d_inode(dentry);
+	struct delegated_inode delegated_inode = { };
+
+	acl_type = posix_acl_type(acl_name);
+	if (acl_type < 0)
+		return -EINVAL;
+
+	if (kacl) {
+		/*
+		 * If we're on an idmapped mount translate from mount specific
+		 * vfs{g,u}id_t into global filesystem k{g,u}id_t.
+		 * Afterwards we can cache the POSIX ACLs filesystem wide and -
+		 * if this is a filesystem with a backing store - ultimately
+		 * translate them to backing store values.
+		 */
+		error = vfs_set_acl_idmapped_mnt(idmap, i_user_ns(inode), kacl);
+		if (error)
+			return error;
+	}
+
+retry_deleg:
+	inode_lock(inode);
+
+	/*
+	 * We only care about restrictions the inode struct itself places upon
+	 * us otherwise POSIX ACLs aren't subject to any VFS restrictions.
+	 */
+	error = may_write_xattr(idmap, inode);
+	if (error)
+		goto out_inode_unlock;
+
+	error = security_inode_set_acl(idmap, dentry, acl_name, kacl);
+	if (error)
+		goto out_inode_unlock;
+
+	error = try_break_deleg(inode, 0, &delegated_inode);
+	if (error)
+		goto out_inode_unlock;
+
+	if (likely(!is_bad_inode(inode)))
+		error = set_posix_acl(idmap, dentry, acl_type, kacl);
+	else
+		error = -EIO;
+	if (!error) {
+		fsnotify_xattr(dentry);
+		security_inode_post_set_acl(dentry, acl_name, kacl);
+	}
+
+out_inode_unlock:
+	inode_unlock(inode);
+
+	if (is_delegated(&delegated_inode)) {
+		error = break_deleg_wait(&delegated_inode);
+		if (!error)
+			goto retry_deleg;
+	}
+
+	return error;
+}
+EXPORT_SYMBOL_GPL(vfs_set_acl);
+
+/**
+ * vfs_get_acl - get posix acls
+ * @idmap: idmap of the mount
+ * @dentry: the dentry based on which to retrieve the posix acls
+ * @acl_name: the name of the posix acl
+ *
+ * This function retrieves @kacl from the filesystem. The caller must all
+ * posix_acl_release() on @kacl.
+ *
+ * Return: On success POSIX ACLs in VFS format, on error negative errno.
+ */
+struct posix_acl *vfs_get_acl(struct mnt_idmap *idmap,
+			      struct dentry *dentry, const char *acl_name)
+{
+	struct inode *inode = d_inode(dentry);
+	struct posix_acl *acl;
+	int acl_type, error;
+
+	acl_type = posix_acl_type(acl_name);
+	if (acl_type < 0)
+		return ERR_PTR(-EINVAL);
+
+	/*
+	 * The VFS has no restrictions on reading POSIX ACLs so calling
+	 * something like xattr_permission() isn't needed. Only LSMs get a say.
+	 */
+	error = security_inode_get_acl(idmap, dentry, acl_name);
+	if (error)
+		return ERR_PTR(error);
+
+	if (!IS_POSIXACL(inode))
+		return ERR_PTR(-EOPNOTSUPP);
+	if (S_ISLNK(inode->i_mode))
+		return ERR_PTR(-EOPNOTSUPP);
+
+	acl = __get_acl(idmap, dentry, inode, acl_type);
+	if (IS_ERR(acl))
+		return acl;
+	if (!acl)
+		return ERR_PTR(-ENODATA);
+
+	return acl;
+}
+EXPORT_SYMBOL_GPL(vfs_get_acl);
+
+/**
+ * vfs_remove_acl - remove posix acls
+ * @idmap: idmap of the mount
+ * @dentry: the dentry based on which to retrieve the posix acls
+ * @acl_name: the name of the posix acl
+ *
+ * This function removes posix acls.
+ *
+ * Return: On success 0, on error negative errno.
+ */
+int vfs_remove_acl(struct mnt_idmap *idmap, struct dentry *dentry,
+		   const char *acl_name)
+{
+	int acl_type;
+	int error;
+	struct inode *inode = d_inode(dentry);
+	struct delegated_inode delegated_inode = { };
+
+	acl_type = posix_acl_type(acl_name);
+	if (acl_type < 0)
+		return -EINVAL;
+
+retry_deleg:
+	inode_lock(inode);
+
+	/*
+	 * We only care about restrictions the inode struct itself places upon
+	 * us otherwise POSIX ACLs aren't subject to any VFS restrictions.
+	 */
+	error = may_write_xattr(idmap, inode);
+	if (error)
+		goto out_inode_unlock;
+
+	error = security_inode_remove_acl(idmap, dentry, acl_name);
+	if (error)
+		goto out_inode_unlock;
+
+	error = try_break_deleg(inode, 0, &delegated_inode);
+	if (error)
+		goto out_inode_unlock;
+
+	if (likely(!is_bad_inode(inode)))
+		error = set_posix_acl(idmap, dentry, acl_type, NULL);
+	else
+		error = -EIO;
+	if (!error) {
+		fsnotify_xattr(dentry);
+		security_inode_post_remove_acl(idmap, dentry, acl_name);
+	}
+
+out_inode_unlock:
+	inode_unlock(inode);
+
+	if (is_delegated(&delegated_inode)) {
+		error = break_deleg_wait(&delegated_inode);
+		if (!error)
+			goto retry_deleg;
+	}
+
+	return error;
+}
+EXPORT_SYMBOL_GPL(vfs_remove_acl);
+
+int do_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
+	       const char *acl_name, const void *kvalue, size_t size)
+{
+	int error;
+	struct posix_acl *acl = NULL;
+
+	if (size) {
+		/*
+		 * Note that posix_acl_from_xattr() uses GFP_NOFS when it
+		 * probably doesn't need to here.
+		 */
+		acl = posix_acl_from_xattr(current_user_ns(), kvalue, size);
+		if (IS_ERR(acl))
+			return PTR_ERR(acl);
+	}
+
+	error = vfs_set_acl(idmap, dentry, acl_name, acl);
+	posix_acl_release(acl);
+	return error;
+}
+
+ssize_t do_get_acl(struct mnt_idmap *idmap, struct dentry *dentry,
+		   const char *acl_name, void *kvalue, size_t size)
+{
+	ssize_t error;
+	struct posix_acl *acl;
+
+	acl = vfs_get_acl(idmap, dentry, acl_name);
+	if (IS_ERR(acl))
+		return PTR_ERR(acl);
+
+	error = vfs_posix_acl_to_xattr(idmap, d_inode(dentry),
+				       acl, kvalue, size);
+	posix_acl_release(acl);
+	return error;
+}