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, 380 insertions, 0 deletions

diff --git a/security/inode.c b/security/inode.c
new file mode 100644
index 000000000..080402367
--- /dev/null
+++ b/security/inode.c
@@ -0,0 +1,380 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  inode.c - securityfs
+ *
+ *  Copyright (C) 2005 Greg Kroah-Hartman <gregkh@suse.de>
+ *
+ *  Based on fs/debugfs/inode.c which had the following copyright notice:
+ *    Copyright (C) 2004 Greg Kroah-Hartman <greg@kroah.com>
+ *    Copyright (C) 2004 IBM Inc.
+ */
+
+/* #define DEBUG */
+#include <linux/sysfs.h>
+#include <linux/kobject.h>
+#include <linux/fs.h>
+#include <linux/fs_context.h>
+#include <linux/mount.h>
+#include <linux/pagemap.h>
+#include <linux/init.h>
+#include <linux/namei.h>
+#include <linux/security.h>
+#include <linux/lsm_hooks.h>
+#include <linux/magic.h>
+
+#include "lsm.h"
+
+static struct vfsmount *mount;
+static int mount_count;
+
+static void securityfs_free_inode(struct inode *inode)
+{
+	if (S_ISLNK(inode->i_mode))
+		kfree_const(inode->i_link);
+	free_inode_nonrcu(inode);
+}
+
+static const struct super_operations securityfs_super_operations = {
+	.statfs		= simple_statfs,
+	.free_inode	= securityfs_free_inode,
+};
+
+static int securityfs_fill_super(struct super_block *sb, struct fs_context *fc)
+{
+	static const struct tree_descr files[] = {{""}};
+	int error;
+
+	error = simple_fill_super(sb, SECURITYFS_MAGIC, files);
+	if (error)
+		return error;
+
+	sb->s_op = &securityfs_super_operations;
+
+	return 0;
+}
+
+static int securityfs_get_tree(struct fs_context *fc)
+{
+	return get_tree_single(fc, securityfs_fill_super);
+}
+
+static const struct fs_context_operations securityfs_context_ops = {
+	.get_tree	= securityfs_get_tree,
+};
+
+static int securityfs_init_fs_context(struct fs_context *fc)
+{
+	fc->ops = &securityfs_context_ops;
+	return 0;
+}
+
+static struct file_system_type fs_type = {
+	.owner =	THIS_MODULE,
+	.name =		"securityfs",
+	.init_fs_context = securityfs_init_fs_context,
+	.kill_sb =	kill_anon_super,
+};
+
+/**
+ * securityfs_create_dentry - create a dentry in the securityfs filesystem
+ *
+ * @name: a pointer to a string containing the name of the file to create.
+ * @mode: the permission that the file should have
+ * @parent: a pointer to the parent dentry for this file.  This should be a
+ *          directory dentry if set.  If this parameter is %NULL, then the
+ *          file will be created in the root of the securityfs filesystem.
+ * @data: a pointer to something that the caller will want to get to later
+ *        on.  The inode.i_private pointer will point to this value on
+ *        the open() call.
+ * @fops: a pointer to a struct file_operations that should be used for
+ *        this file.
+ * @iops: a point to a struct of inode_operations that should be used for
+ *        this file/dir
+ *
+ * This is the basic "create a file/dir/symlink" function for
+ * securityfs.  It allows for a wide range of flexibility in creating
+ * a file, or a directory (if you want to create a directory, the
+ * securityfs_create_dir() function is recommended to be used
+ * instead).
+ *
+ * This function returns a pointer to a dentry if it succeeds.  This
+ * pointer must be passed to the securityfs_remove() function when the
+ * file is to be removed (no automatic cleanup happens if your module
+ * is unloaded, you are responsible here).  If an error occurs, the
+ * function will return the error value (via ERR_PTR).
+ *
+ * If securityfs is not enabled in the kernel, the value %-ENODEV is
+ * returned.
+ */
+static struct dentry *securityfs_create_dentry(const char *name, umode_t mode,
+					struct dentry *parent, void *data,
+					const struct file_operations *fops,
+					const struct inode_operations *iops)
+{
+	struct dentry *dentry;
+	struct inode *dir, *inode;
+	int error;
+	bool pinned = false;
+
+	if (!(mode & S_IFMT))
+		mode = (mode & S_IALLUGO) | S_IFREG;
+
+	pr_debug("securityfs: creating file '%s'\n",name);
+
+	if (!parent) {
+		error = simple_pin_fs(&fs_type, &mount, &mount_count);
+		if (error)
+			return ERR_PTR(error);
+		pinned = true;
+		parent = mount->mnt_root;
+	}
+
+	inode = new_inode(parent->d_sb);
+	if (unlikely(!inode)) {
+		dentry = ERR_PTR(-ENOMEM);
+		goto out;
+	}
+
+	dir = d_inode(parent);
+
+	dentry = simple_start_creating(parent, name);
+	if (IS_ERR(dentry)) {
+		iput(inode);
+		goto out;
+	}
+	inode->i_ino = get_next_ino();
+	inode->i_mode = mode;
+	simple_inode_init_ts(inode);
+	inode->i_private = data;
+	if (S_ISDIR(mode)) {
+		inode->i_op = &simple_dir_inode_operations;
+		inode->i_fop = &simple_dir_operations;
+		inc_nlink(inode);
+		inc_nlink(dir);
+	} else if (S_ISLNK(mode)) {
+		inode->i_op = iops ? iops : &simple_symlink_inode_operations;
+		inode->i_link = data;
+	} else {
+		inode->i_fop = fops;
+	}
+	d_make_persistent(dentry, inode);
+	simple_done_creating(dentry);
+	return dentry; // borrowed
+
+out:
+	if (pinned)
+		simple_release_fs(&mount, &mount_count);
+	return dentry;
+}
+
+/**
+ * securityfs_create_file - create a file in the securityfs filesystem
+ *
+ * @name: a pointer to a string containing the name of the file to create.
+ * @mode: the permission that the file should have
+ * @parent: a pointer to the parent dentry for this file.  This should be a
+ *          directory dentry if set.  If this parameter is %NULL, then the
+ *          file will be created in the root of the securityfs filesystem.
+ * @data: a pointer to something that the caller will want to get to later
+ *        on.  The inode.i_private pointer will point to this value on
+ *        the open() call.
+ * @fops: a pointer to a struct file_operations that should be used for
+ *        this file.
+ *
+ * This function creates a file in securityfs with the given @name.
+ *
+ * This function returns a pointer to a dentry if it succeeds.  This
+ * pointer must be passed to the securityfs_remove() function when the file is
+ * to be removed (no automatic cleanup happens if your module is unloaded,
+ * you are responsible here).  If an error occurs, the function will return
+ * the error value (via ERR_PTR).
+ *
+ * If securityfs is not enabled in the kernel, the value %-ENODEV is
+ * returned.
+ */
+struct dentry *securityfs_create_file(const char *name, umode_t mode,
+				      struct dentry *parent, void *data,
+				      const struct file_operations *fops)
+{
+	return securityfs_create_dentry(name, mode, parent, data, fops, NULL);
+}
+EXPORT_SYMBOL_GPL(securityfs_create_file);
+
+/**
+ * securityfs_create_dir - create a directory in the securityfs filesystem
+ *
+ * @name: a pointer to a string containing the name of the directory to
+ *        create.
+ * @parent: a pointer to the parent dentry for this file.  This should be a
+ *          directory dentry if set.  If this parameter is %NULL, then the
+ *          directory will be created in the root of the securityfs filesystem.
+ *
+ * This function creates a directory in securityfs with the given @name.
+ *
+ * This function returns a pointer to a dentry if it succeeds.  This
+ * pointer must be passed to the securityfs_remove() function when the file is
+ * to be removed (no automatic cleanup happens if your module is unloaded,
+ * you are responsible here).  If an error occurs, the function will return
+ * the error value (via ERR_PTR).
+ *
+ * If securityfs is not enabled in the kernel, the value %-ENODEV is
+ * returned.
+ */
+struct dentry *securityfs_create_dir(const char *name, struct dentry *parent)
+{
+	return securityfs_create_file(name, S_IFDIR | 0755, parent, NULL, NULL);
+}
+EXPORT_SYMBOL_GPL(securityfs_create_dir);
+
+/**
+ * securityfs_create_symlink - create a symlink in the securityfs filesystem
+ *
+ * @name: a pointer to a string containing the name of the symlink to
+ *        create.
+ * @parent: a pointer to the parent dentry for the symlink.  This should be a
+ *          directory dentry if set.  If this parameter is %NULL, then the
+ *          directory will be created in the root of the securityfs filesystem.
+ * @target: a pointer to a string containing the name of the symlink's target.
+ *          If this parameter is %NULL, then the @iops parameter needs to be
+ *          setup to handle .readlink and .get_link inode_operations.
+ * @iops: a pointer to the struct inode_operations to use for the symlink. If
+ *        this parameter is %NULL, then the default simple_symlink_inode
+ *        operations will be used.
+ *
+ * This function creates a symlink in securityfs with the given @name.
+ *
+ * This function returns a pointer to a dentry if it succeeds.  This
+ * pointer must be passed to the securityfs_remove() function when the file is
+ * to be removed (no automatic cleanup happens if your module is unloaded,
+ * you are responsible here).  If an error occurs, the function will return
+ * the error value (via ERR_PTR).
+ *
+ * If securityfs is not enabled in the kernel, the value %-ENODEV is
+ * returned.
+ */
+struct dentry *securityfs_create_symlink(const char *name,
+					 struct dentry *parent,
+					 const char *target,
+					 const struct inode_operations *iops)
+{
+	struct dentry *dent;
+	const char *link = NULL;
+
+	if (target) {
+		link = kstrdup_const(target, GFP_KERNEL);
+		if (!link)
+			return ERR_PTR(-ENOMEM);
+	}
+	dent = securityfs_create_dentry(name, S_IFLNK | 0444, parent,
+					(void *)link, NULL, iops);
+	if (IS_ERR(dent))
+		kfree_const(link);
+
+	return dent;
+}
+EXPORT_SYMBOL_GPL(securityfs_create_symlink);
+
+static void remove_one(struct dentry *victim)
+{
+	if (victim->d_parent == victim->d_sb->s_root)
+		simple_release_fs(&mount, &mount_count);
+}
+
+/**
+ * securityfs_remove - removes a file or directory from the securityfs filesystem
+ *
+ * @dentry: a pointer to a the dentry of the file or directory to be removed.
+ *
+ * This function removes a file or directory in securityfs that was previously
+ * created with a call to another securityfs function (like
+ * securityfs_create_file() or variants thereof.)
+ *
+ * This function is required to be called in order for the file to be
+ * removed. No automatic cleanup of files will happen when a module is
+ * removed; you are responsible here.
+ *
+ * AV: when applied to directory it will take all children out; no need to call
+ * it for descendents if ancestor is getting killed.
+ */
+void securityfs_remove(struct dentry *dentry)
+{
+	if (IS_ERR_OR_NULL(dentry))
+		return;
+
+	simple_pin_fs(&fs_type, &mount, &mount_count);
+	simple_recursive_removal(dentry, remove_one);
+	simple_release_fs(&mount, &mount_count);
+}
+EXPORT_SYMBOL_GPL(securityfs_remove);
+
+#ifdef CONFIG_SECURITY
+#include <linux/spinlock.h>
+
+static struct dentry *lsm_dentry;
+
+static ssize_t lsm_read(struct file *filp, char __user *buf, size_t count,
+			loff_t *ppos)
+{
+	int i;
+	static char *str;
+	static size_t len;
+	static DEFINE_SPINLOCK(lock);
+
+	/* NOTE: we never free or modify the string once it is set */
+
+	if (unlikely(!str || !len)) {
+		char *str_tmp;
+		size_t len_tmp = 0;
+
+		for (i = 0; i < lsm_active_cnt; i++)
+			/* the '+ 1' accounts for either a comma or a NUL */
+			len_tmp += strlen(lsm_idlist[i]->name) + 1;
+
+		str_tmp = kmalloc(len_tmp, GFP_KERNEL);
+		if (!str_tmp)
+			return -ENOMEM;
+		str_tmp[0] = '\0';
+
+		for (i = 0; i < lsm_active_cnt; i++) {
+			if (i > 0)
+				strcat(str_tmp, ",");
+			strcat(str_tmp, lsm_idlist[i]->name);
+		}
+
+		spin_lock(&lock);
+		if (!str) {
+			str = str_tmp;
+			len = len_tmp - 1;
+		} else
+			kfree(str_tmp);
+		spin_unlock(&lock);
+	}
+
+	return simple_read_from_buffer(buf, count, ppos, str, len);
+}
+
+static const struct file_operations lsm_ops = {
+	.read = lsm_read,
+	.llseek = generic_file_llseek,
+};
+#endif
+
+int __init securityfs_init(void)
+{
+	int retval;
+
+	retval = sysfs_create_mount_point(kernel_kobj, "security");
+	if (retval)
+		return retval;
+
+	retval = register_filesystem(&fs_type);
+	if (retval) {
+		sysfs_remove_mount_point(kernel_kobj, "security");
+		return retval;
+	}
+#ifdef CONFIG_SECURITY
+	lsm_dentry = securityfs_create_file("lsm", 0444, NULL, NULL,
+						&lsm_ops);
+#endif
+	return 0;
+}