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, 527 insertions, 0 deletions

diff --git a/fs/btrfs/xattr.c b/fs/btrfs/xattr.c
new file mode 100644
index 000000000..ab55d10bd
--- /dev/null
+++ b/fs/btrfs/xattr.c
@@ -0,0 +1,527 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2007 Red Hat.  All rights reserved.
+ */
+
+#include <linux/init.h>
+#include <linux/fs.h>
+#include <linux/slab.h>
+#include <linux/rwsem.h>
+#include <linux/xattr.h>
+#include <linux/security.h>
+#include <linux/posix_acl_xattr.h>
+#include <linux/iversion.h>
+#include <linux/sched/mm.h>
+#include "ctree.h"
+#include "fs.h"
+#include "messages.h"
+#include "btrfs_inode.h"
+#include "transaction.h"
+#include "xattr.h"
+#include "disk-io.h"
+#include "props.h"
+#include "locking.h"
+#include "accessors.h"
+#include "dir-item.h"
+
+int btrfs_getxattr(const struct inode *inode, const char *name,
+				void *buffer, size_t size)
+{
+	struct btrfs_dir_item *di;
+	struct btrfs_root *root = BTRFS_I(inode)->root;
+	BTRFS_PATH_AUTO_FREE(path);
+	struct extent_buffer *leaf;
+	unsigned long data_ptr;
+
+	path = btrfs_alloc_path();
+	if (!path)
+		return -ENOMEM;
+
+	/* lookup the xattr by name */
+	di = btrfs_lookup_xattr(NULL, root, path, btrfs_ino(BTRFS_I(inode)),
+			name, strlen(name), 0);
+	if (!di)
+		return -ENODATA;
+	if (IS_ERR(di))
+		return PTR_ERR(di);
+
+	leaf = path->nodes[0];
+	/* if size is 0, that means we want the size of the attr */
+	if (!size)
+		return btrfs_dir_data_len(leaf, di);
+
+	/* now get the data out of our dir_item */
+	if (btrfs_dir_data_len(leaf, di) > size)
+		return -ERANGE;
+
+	/*
+	 * The way things are packed into the leaf is like this
+	 * |struct btrfs_dir_item|name|data|
+	 * where name is the xattr name, so security.foo, and data is the
+	 * content of the xattr.  data_ptr points to the location in memory
+	 * where the data starts in the in memory leaf
+	 */
+	data_ptr = (unsigned long)((char *)(di + 1) +
+				   btrfs_dir_name_len(leaf, di));
+	read_extent_buffer(leaf, buffer, data_ptr,
+			   btrfs_dir_data_len(leaf, di));
+	return btrfs_dir_data_len(leaf, di);
+}
+
+int btrfs_setxattr(struct btrfs_trans_handle *trans, struct inode *inode,
+		   const char *name, const void *value, size_t size, int flags)
+{
+	struct btrfs_dir_item *di = NULL;
+	struct btrfs_root *root = BTRFS_I(inode)->root;
+	BTRFS_PATH_AUTO_FREE(path);
+	size_t name_len = strlen(name);
+	int ret = 0;
+
+	ASSERT(trans);
+
+	if (name_len + size > BTRFS_MAX_XATTR_SIZE(root->fs_info))
+		return -ENOSPC;
+
+	path = btrfs_alloc_path();
+	if (!path)
+		return -ENOMEM;
+	path->skip_release_on_error = true;
+
+	if (!value) {
+		di = btrfs_lookup_xattr(trans, root, path,
+				btrfs_ino(BTRFS_I(inode)), name, name_len, -1);
+		if (!di && (flags & XATTR_REPLACE))
+			ret = -ENODATA;
+		else if (IS_ERR(di))
+			ret = PTR_ERR(di);
+		else if (di)
+			ret = btrfs_delete_one_dir_name(trans, root, path, di);
+		goto out;
+	}
+
+	/*
+	 * For a replace we can't just do the insert blindly.
+	 * Do a lookup first (read-only btrfs_search_slot), and return if xattr
+	 * doesn't exist. If it exists, fall down below to the insert/replace
+	 * path - we can't race with a concurrent xattr delete, because the VFS
+	 * locks the inode's i_mutex before calling setxattr or removexattr.
+	 */
+	if (flags & XATTR_REPLACE) {
+		btrfs_assert_inode_locked(BTRFS_I(inode));
+		di = btrfs_lookup_xattr(NULL, root, path,
+				btrfs_ino(BTRFS_I(inode)), name, name_len, 0);
+		if (!di)
+			ret = -ENODATA;
+		else if (IS_ERR(di))
+			ret = PTR_ERR(di);
+		if (ret)
+			goto out;
+		btrfs_release_path(path);
+		di = NULL;
+	}
+
+	ret = btrfs_insert_xattr_item(trans, root, path, btrfs_ino(BTRFS_I(inode)),
+				      name, name_len, value, size);
+	if (ret == -EOVERFLOW) {
+		/*
+		 * We have an existing item in a leaf, split_leaf couldn't
+		 * expand it. That item might have or not a dir_item that
+		 * matches our target xattr, so lets check.
+		 */
+		ret = 0;
+		btrfs_assert_tree_write_locked(path->nodes[0]);
+		di = btrfs_match_dir_item_name(path, name, name_len);
+		if (!di && !(flags & XATTR_REPLACE)) {
+			ret = -ENOSPC;
+			goto out;
+		}
+	} else if (ret == -EEXIST) {
+		ret = 0;
+		di = btrfs_match_dir_item_name(path, name, name_len);
+		ASSERT(di); /* logic error */
+	} else if (ret) {
+		goto out;
+	}
+
+	if (di && (flags & XATTR_CREATE)) {
+		ret = -EEXIST;
+		goto out;
+	}
+
+	if (di) {
+		/*
+		 * We're doing a replace, and it must be atomic, that is, at
+		 * any point in time we have either the old or the new xattr
+		 * value in the tree. We don't want readers (getxattr and
+		 * listxattrs) to miss a value, this is specially important
+		 * for ACLs.
+		 */
+		const int slot = path->slots[0];
+		struct extent_buffer *leaf = path->nodes[0];
+		const u16 old_data_len = btrfs_dir_data_len(leaf, di);
+		const u32 item_size = btrfs_item_size(leaf, slot);
+		const u32 data_size = sizeof(*di) + name_len + size;
+		unsigned long data_ptr;
+		char *ptr;
+
+		if (size > old_data_len) {
+			if (btrfs_leaf_free_space(leaf) <
+			    (size - old_data_len)) {
+				ret = -ENOSPC;
+				goto out;
+			}
+		}
+
+		if (old_data_len + name_len + sizeof(*di) == item_size) {
+			/* No other xattrs packed in the same leaf item. */
+			if (size > old_data_len)
+				btrfs_extend_item(trans, path, size - old_data_len);
+			else if (size < old_data_len)
+				btrfs_truncate_item(trans, path, data_size, 1);
+		} else {
+			/* There are other xattrs packed in the same item. */
+			ret = btrfs_delete_one_dir_name(trans, root, path, di);
+			if (ret)
+				goto out;
+			btrfs_extend_item(trans, path, data_size);
+		}
+
+		ptr = btrfs_item_ptr(leaf, slot, char);
+		ptr += btrfs_item_size(leaf, slot) - data_size;
+		di = (struct btrfs_dir_item *)ptr;
+		btrfs_set_dir_data_len(leaf, di, size);
+		data_ptr = ((unsigned long)(di + 1)) + name_len;
+		write_extent_buffer(leaf, value, data_ptr, size);
+	} else {
+		/*
+		 * Insert, and we had space for the xattr, so path->slots[0] is
+		 * where our xattr dir_item is and btrfs_insert_xattr_item()
+		 * filled it.
+		 */
+	}
+out:
+	if (!ret) {
+		set_bit(BTRFS_INODE_COPY_EVERYTHING,
+			&BTRFS_I(inode)->runtime_flags);
+		clear_bit(BTRFS_INODE_NO_XATTRS, &BTRFS_I(inode)->runtime_flags);
+	}
+	return ret;
+}
+
+/*
+ * @value: "" makes the attribute to empty, NULL removes it
+ */
+int btrfs_setxattr_trans(struct inode *inode, const char *name,
+			 const void *value, size_t size, int flags)
+{
+	struct btrfs_root *root = BTRFS_I(inode)->root;
+	struct btrfs_trans_handle *trans;
+	const bool start_trans = (current->journal_info == NULL);
+	int ret;
+
+	if (start_trans) {
+		/*
+		 * 1 unit for inserting/updating/deleting the xattr
+		 * 1 unit for the inode item update
+		 */
+		trans = btrfs_start_transaction(root, 2);
+		if (IS_ERR(trans))
+			return PTR_ERR(trans);
+	} else {
+		/*
+		 * This can happen when smack is enabled and a directory is being
+		 * created. It happens through d_instantiate_new(), which calls
+		 * smack_d_instantiate(), which in turn calls __vfs_setxattr() to
+		 * set the transmute xattr (XATTR_NAME_SMACKTRANSMUTE) on the
+		 * inode. We have already reserved space for the xattr and inode
+		 * update at btrfs_mkdir(), so just use the transaction handle.
+		 * We don't join or start a transaction, as that will reset the
+		 * block_rsv of the handle and trigger a warning for the start
+		 * case.
+		 */
+		ASSERT(strncmp(name, XATTR_SECURITY_PREFIX,
+			       XATTR_SECURITY_PREFIX_LEN) == 0);
+		trans = current->journal_info;
+	}
+
+	ret = btrfs_setxattr(trans, inode, name, value, size, flags);
+	if (ret)
+		goto out;
+
+	inode_inc_iversion(inode);
+	inode_set_ctime_current(inode);
+	ret = btrfs_update_inode(trans, BTRFS_I(inode));
+	if (ret)
+		btrfs_abort_transaction(trans, ret);
+out:
+	if (start_trans)
+		btrfs_end_transaction(trans);
+	return ret;
+}
+
+ssize_t btrfs_listxattr(struct dentry *dentry, char *buffer, size_t size)
+{
+	struct btrfs_key found_key;
+	struct btrfs_key key;
+	struct inode *inode = d_inode(dentry);
+	struct btrfs_root *root = BTRFS_I(inode)->root;
+	BTRFS_PATH_AUTO_FREE(path);
+	int iter_ret = 0;
+	int ret = 0;
+	size_t total_size = 0, size_left = size;
+
+	/*
+	 * ok we want all objects associated with this id.
+	 * NOTE: we set key.offset = 0; because we want to start with the
+	 * first xattr that we find and walk forward
+	 */
+	key.objectid = btrfs_ino(BTRFS_I(inode));
+	key.type = BTRFS_XATTR_ITEM_KEY;
+	key.offset = 0;
+
+	path = btrfs_alloc_path();
+	if (!path)
+		return -ENOMEM;
+	path->reada = READA_FORWARD;
+
+	/* search for our xattrs */
+	btrfs_for_each_slot(root, &key, &found_key, path, iter_ret) {
+		struct extent_buffer *leaf;
+		int slot;
+		struct btrfs_dir_item *di;
+		u32 item_size;
+		u32 cur;
+
+		leaf = path->nodes[0];
+		slot = path->slots[0];
+
+		/* check to make sure this item is what we want */
+		if (found_key.objectid != key.objectid)
+			break;
+		if (found_key.type > BTRFS_XATTR_ITEM_KEY)
+			break;
+		if (found_key.type < BTRFS_XATTR_ITEM_KEY)
+			continue;
+
+		di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
+		item_size = btrfs_item_size(leaf, slot);
+		cur = 0;
+		while (cur < item_size) {
+			u16 name_len = btrfs_dir_name_len(leaf, di);
+			u16 data_len = btrfs_dir_data_len(leaf, di);
+			u32 this_len = sizeof(*di) + name_len + data_len;
+			unsigned long name_ptr = (unsigned long)(di + 1);
+
+			total_size += name_len + 1;
+			/*
+			 * We are just looking for how big our buffer needs to
+			 * be.
+			 */
+			if (!size)
+				goto next;
+
+			if (!buffer || (name_len + 1) > size_left) {
+			        iter_ret = -ERANGE;
+				break;
+			}
+
+			read_extent_buffer(leaf, buffer, name_ptr, name_len);
+			buffer[name_len] = '\0';
+
+			size_left -= name_len + 1;
+			buffer += name_len + 1;
+next:
+			cur += this_len;
+			di = (struct btrfs_dir_item *)((char *)di + this_len);
+		}
+	}
+
+	if (iter_ret < 0)
+		ret = iter_ret;
+	else
+		ret = total_size;
+
+	return ret;
+}
+
+static int btrfs_xattr_handler_get(const struct xattr_handler *handler,
+				   struct dentry *unused, struct inode *inode,
+				   const char *name, void *buffer, size_t size)
+{
+	name = xattr_full_name(handler, name);
+	return btrfs_getxattr(inode, name, buffer, size);
+}
+
+static int btrfs_xattr_handler_set(const struct xattr_handler *handler,
+				   struct mnt_idmap *idmap,
+				   struct dentry *unused, struct inode *inode,
+				   const char *name, const void *buffer,
+				   size_t size, int flags)
+{
+	if (btrfs_root_readonly(BTRFS_I(inode)->root))
+		return -EROFS;
+
+	name = xattr_full_name(handler, name);
+	return btrfs_setxattr_trans(inode, name, buffer, size, flags);
+}
+
+static int btrfs_xattr_handler_get_security(const struct xattr_handler *handler,
+					    struct dentry *unused,
+					    struct inode *inode,
+					    const char *name, void *buffer,
+					    size_t size)
+{
+	int ret;
+	bool is_cap = false;
+
+	name = xattr_full_name(handler, name);
+
+	/*
+	 * security.capability doesn't cache the results, so calls into us
+	 * constantly to see if there's a capability xattr.  Cache the result
+	 * here in order to avoid wasting time doing lookups for xattrs we know
+	 * don't exist.
+	 */
+	if (strcmp(name, XATTR_NAME_CAPS) == 0) {
+		is_cap = true;
+		if (test_bit(BTRFS_INODE_NO_CAP_XATTR, &BTRFS_I(inode)->runtime_flags))
+			return -ENODATA;
+	}
+
+	ret = btrfs_getxattr(inode, name, buffer, size);
+	if (ret == -ENODATA && is_cap)
+		set_bit(BTRFS_INODE_NO_CAP_XATTR, &BTRFS_I(inode)->runtime_flags);
+	return ret;
+}
+
+static int btrfs_xattr_handler_set_security(const struct xattr_handler *handler,
+					    struct mnt_idmap *idmap,
+					    struct dentry *unused,
+					    struct inode *inode,
+					    const char *name,
+					    const void *buffer,
+					    size_t size, int flags)
+{
+	if (btrfs_root_readonly(BTRFS_I(inode)->root))
+		return -EROFS;
+
+	name = xattr_full_name(handler, name);
+	if (strcmp(name, XATTR_NAME_CAPS) == 0)
+		clear_bit(BTRFS_INODE_NO_CAP_XATTR, &BTRFS_I(inode)->runtime_flags);
+
+	return btrfs_setxattr_trans(inode, name, buffer, size, flags);
+}
+
+static int btrfs_xattr_handler_set_prop(const struct xattr_handler *handler,
+					struct mnt_idmap *idmap,
+					struct dentry *unused, struct inode *inode,
+					const char *name, const void *value,
+					size_t size, int flags)
+{
+	int ret;
+	struct btrfs_trans_handle *trans;
+	struct btrfs_root *root = BTRFS_I(inode)->root;
+
+	name = xattr_full_name(handler, name);
+	ret = btrfs_validate_prop(BTRFS_I(inode), name, value, size);
+	if (ret)
+		return ret;
+
+	if (btrfs_ignore_prop(BTRFS_I(inode), name))
+		return 0;
+
+	trans = btrfs_start_transaction(root, 2);
+	if (IS_ERR(trans))
+		return PTR_ERR(trans);
+
+	ret = btrfs_set_prop(trans, BTRFS_I(inode), name, value, size, flags);
+	if (!ret) {
+		inode_inc_iversion(inode);
+		inode_set_ctime_current(inode);
+		ret = btrfs_update_inode(trans, BTRFS_I(inode));
+		if (ret)
+			btrfs_abort_transaction(trans, ret);
+	}
+
+	btrfs_end_transaction(trans);
+
+	return ret;
+}
+
+static const struct xattr_handler btrfs_security_xattr_handler = {
+	.prefix = XATTR_SECURITY_PREFIX,
+	.get = btrfs_xattr_handler_get_security,
+	.set = btrfs_xattr_handler_set_security,
+};
+
+static const struct xattr_handler btrfs_trusted_xattr_handler = {
+	.prefix = XATTR_TRUSTED_PREFIX,
+	.get = btrfs_xattr_handler_get,
+	.set = btrfs_xattr_handler_set,
+};
+
+static const struct xattr_handler btrfs_user_xattr_handler = {
+	.prefix = XATTR_USER_PREFIX,
+	.get = btrfs_xattr_handler_get,
+	.set = btrfs_xattr_handler_set,
+};
+
+static const struct xattr_handler btrfs_btrfs_xattr_handler = {
+	.prefix = XATTR_BTRFS_PREFIX,
+	.get = btrfs_xattr_handler_get,
+	.set = btrfs_xattr_handler_set_prop,
+};
+
+const struct xattr_handler * const btrfs_xattr_handlers[] = {
+	&btrfs_security_xattr_handler,
+	&btrfs_trusted_xattr_handler,
+	&btrfs_user_xattr_handler,
+	&btrfs_btrfs_xattr_handler,
+	NULL,
+};
+
+static int btrfs_initxattrs(struct inode *inode,
+			    const struct xattr *xattr_array, void *fs_private)
+{
+	struct btrfs_trans_handle *trans = fs_private;
+	const struct xattr *xattr;
+	unsigned int nofs_flag;
+	char *name;
+	int ret = 0;
+
+	/*
+	 * We're holding a transaction handle, so use a NOFS memory allocation
+	 * context to avoid deadlock if reclaim happens.
+	 */
+	nofs_flag = memalloc_nofs_save();
+	for (xattr = xattr_array; xattr->name != NULL; xattr++) {
+		const size_t name_len = XATTR_SECURITY_PREFIX_LEN +
+					strlen(xattr->name) + 1;
+
+		name = kmalloc(name_len, GFP_KERNEL);
+		if (!name) {
+			ret = -ENOMEM;
+			break;
+		}
+		scnprintf(name, name_len, "%s%s", XATTR_SECURITY_PREFIX, xattr->name);
+
+		if (strcmp(name, XATTR_NAME_CAPS) == 0)
+			clear_bit(BTRFS_INODE_NO_CAP_XATTR, &BTRFS_I(inode)->runtime_flags);
+
+		ret = btrfs_setxattr(trans, inode, name, xattr->value,
+				     xattr->value_len, 0);
+		kfree(name);
+		if (ret < 0)
+			break;
+	}
+	memalloc_nofs_restore(nofs_flag);
+	return ret;
+}
+
+int btrfs_xattr_security_init(struct btrfs_trans_handle *trans,
+			      struct inode *inode, struct inode *dir,
+			      const struct qstr *qstr)
+{
+	return security_inode_init_security(inode, dir, qstr,
+					    &btrfs_initxattrs, trans);
+}