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, 467 insertions, 0 deletions

diff --git a/fs/smb/client/dfs.c b/fs/smb/client/dfs.c
new file mode 100644
index 000000000..f65a8a90b
--- /dev/null
+++ b/fs/smb/client/dfs.c
@@ -0,0 +1,467 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2022 Paulo Alcantara <palcantara@suse.de>
+ */
+
+#include "cifsproto.h"
+#include "cifs_debug.h"
+#include "dns_resolve.h"
+#include "fs_context.h"
+#include "dfs.h"
+
+#define DFS_DOM(ctx) (ctx->dfs_root_ses ? ctx->dfs_root_ses->dns_dom : NULL)
+
+/**
+ * dfs_parse_target_referral - set fs context for dfs target referral
+ *
+ * @full_path: full path in UNC format.
+ * @ref: dfs referral pointer.
+ * @ctx: smb3 fs context pointer.
+ *
+ * Return zero if dfs referral was parsed correctly, otherwise non-zero.
+ */
+int dfs_parse_target_referral(const char *full_path, const struct dfs_info3_param *ref,
+			      struct smb3_fs_context *ctx)
+{
+	int rc;
+	const char *prepath = NULL;
+	char *path;
+
+	if (!full_path || !*full_path || !ref || !ctx)
+		return -EINVAL;
+
+	if (WARN_ON_ONCE(!ref->node_name || ref->path_consumed < 0))
+		return -EINVAL;
+
+	if (strlen(full_path) - ref->path_consumed) {
+		prepath = full_path + ref->path_consumed;
+		/* skip initial delimiter */
+		if (*prepath == '/' || *prepath == '\\')
+			prepath++;
+	}
+
+	path = cifs_build_devname(ref->node_name, prepath);
+	if (IS_ERR(path))
+		return PTR_ERR(path);
+
+	rc = smb3_parse_devname(path, ctx);
+	if (rc)
+		goto out;
+
+	rc = dns_resolve_unc(DFS_DOM(ctx), path,
+			     (struct sockaddr *)&ctx->dstaddr);
+out:
+	kfree(path);
+	return rc;
+}
+
+static int get_session(struct cifs_mount_ctx *mnt_ctx, const char *full_path)
+{
+	struct smb3_fs_context *ctx = mnt_ctx->fs_ctx;
+	int rc;
+
+	ctx->leaf_fullpath = (char *)full_path;
+	ctx->dns_dom = DFS_DOM(ctx);
+	rc = cifs_mount_get_session(mnt_ctx);
+	ctx->leaf_fullpath = ctx->dns_dom = NULL;
+
+	return rc;
+}
+
+/*
+ * Get an active reference of @ses so that next call to cifs_put_tcon() won't
+ * release it as any new DFS referrals must go through its IPC tcon.
+ */
+static void set_root_smb_session(struct cifs_mount_ctx *mnt_ctx)
+{
+	struct smb3_fs_context *ctx = mnt_ctx->fs_ctx;
+	struct cifs_ses *ses = mnt_ctx->ses;
+
+	if (ses) {
+		spin_lock(&cifs_tcp_ses_lock);
+		cifs_smb_ses_inc_refcount(ses);
+		spin_unlock(&cifs_tcp_ses_lock);
+	}
+	ctx->dfs_root_ses = ses;
+}
+
+static inline int parse_dfs_target(struct smb3_fs_context *ctx,
+				   struct dfs_ref_walk *rw,
+				   struct dfs_info3_param *tgt)
+{
+	int rc;
+	const char *fpath = ref_walk_fpath(rw) + 1;
+
+	rc = ref_walk_get_tgt(rw, tgt);
+	if (!rc)
+		rc = dfs_parse_target_referral(fpath, tgt, ctx);
+	return rc;
+}
+
+static int setup_dfs_ref(struct dfs_info3_param *tgt, struct dfs_ref_walk *rw)
+{
+	struct cifs_sb_info *cifs_sb = rw->mnt_ctx->cifs_sb;
+	struct smb3_fs_context *ctx = rw->mnt_ctx->fs_ctx;
+	char *ref_path, *full_path;
+	int rc;
+
+	set_root_smb_session(rw->mnt_ctx);
+	ref_walk_ses(rw) = ctx->dfs_root_ses;
+
+	full_path = smb3_fs_context_fullpath(ctx, CIFS_DIR_SEP(cifs_sb));
+	if (IS_ERR(full_path))
+		return PTR_ERR(full_path);
+
+	if (!tgt || (tgt->server_type == DFS_TYPE_LINK &&
+		     DFS_INTERLINK(tgt->flags)))
+		ref_path = dfs_get_path(cifs_sb, ctx->UNC);
+	else
+		ref_path = dfs_get_path(cifs_sb, full_path);
+	if (IS_ERR(ref_path)) {
+		rc = PTR_ERR(ref_path);
+		kfree(full_path);
+		return rc;
+	}
+	ref_walk_path(rw) = ref_path;
+	ref_walk_fpath(rw) = full_path;
+
+	return dfs_get_referral(rw->mnt_ctx,
+				ref_walk_path(rw) + 1,
+				ref_walk_tl(rw));
+}
+
+static int __dfs_referral_walk(struct dfs_ref_walk *rw)
+{
+	struct smb3_fs_context *ctx = rw->mnt_ctx->fs_ctx;
+	struct cifs_mount_ctx *mnt_ctx = rw->mnt_ctx;
+	struct dfs_info3_param tgt = {};
+	int rc = -ENOENT;
+
+again:
+	do {
+		ctx->dfs_root_ses = ref_walk_ses(rw);
+		while (ref_walk_next_tgt(rw)) {
+			rc = parse_dfs_target(ctx, rw, &tgt);
+			if (rc)
+				continue;
+
+			cifs_mount_put_conns(mnt_ctx);
+			rc = get_session(mnt_ctx, ref_walk_path(rw));
+			if (rc)
+				continue;
+
+			rc = cifs_mount_get_tcon(mnt_ctx);
+			if (rc) {
+				if (tgt.server_type == DFS_TYPE_LINK &&
+				    DFS_INTERLINK(tgt.flags))
+					rc = -EREMOTE;
+			} else {
+				rc = cifs_is_path_remote(mnt_ctx);
+				if (!rc) {
+					ref_walk_set_tgt_hint(rw);
+					break;
+				}
+			}
+			if (rc == -EREMOTE) {
+				rc = ref_walk_advance(rw);
+				if (!rc) {
+					rc = setup_dfs_ref(&tgt, rw);
+					if (rc)
+						break;
+					ref_walk_mark_end(rw);
+					goto again;
+				}
+			}
+		}
+	} while (rc && ref_walk_descend(rw));
+
+	free_dfs_info_param(&tgt);
+	return rc;
+}
+
+static int dfs_referral_walk(struct cifs_mount_ctx *mnt_ctx,
+			     struct dfs_ref_walk **rw)
+{
+	int rc;
+
+	*rw = ref_walk_alloc();
+	if (IS_ERR(*rw)) {
+		rc = PTR_ERR(*rw);
+		*rw = NULL;
+		return rc;
+	}
+
+	ref_walk_init(*rw, mnt_ctx);
+	rc = setup_dfs_ref(NULL, *rw);
+	if (!rc)
+		rc = __dfs_referral_walk(*rw);
+	return rc;
+}
+
+static int __dfs_mount_share(struct cifs_mount_ctx *mnt_ctx)
+{
+	struct cifs_sb_info *cifs_sb = mnt_ctx->cifs_sb;
+	struct smb3_fs_context *ctx = mnt_ctx->fs_ctx;
+	struct dfs_ref_walk *rw = NULL;
+	struct cifs_tcon *tcon;
+	char *origin_fullpath;
+	int rc;
+
+	origin_fullpath = dfs_get_path(cifs_sb, ctx->source);
+	if (IS_ERR(origin_fullpath))
+		return PTR_ERR(origin_fullpath);
+
+	rc = dfs_referral_walk(mnt_ctx, &rw);
+	if (!rc) {
+		/*
+		 * Prevent superblock from being created with any missing
+		 * connections.
+		 */
+		if (WARN_ON(!mnt_ctx->server))
+			rc = -EHOSTDOWN;
+		else if (WARN_ON(!mnt_ctx->ses))
+			rc = -EACCES;
+		else if (WARN_ON(!mnt_ctx->tcon))
+			rc = -ENOENT;
+	}
+	if (rc)
+		goto out;
+
+	tcon = mnt_ctx->tcon;
+	spin_lock(&tcon->tc_lock);
+	tcon->origin_fullpath = origin_fullpath;
+	origin_fullpath = NULL;
+	ref_walk_set_tcon(rw, tcon);
+	spin_unlock(&tcon->tc_lock);
+	queue_delayed_work(dfscache_wq, &tcon->dfs_cache_work,
+			   dfs_cache_get_ttl() * HZ);
+
+out:
+	kfree(origin_fullpath);
+	ref_walk_free(rw);
+	return rc;
+}
+
+/*
+ * If @ctx->dfs_automount, then update @ctx->dstaddr earlier with the DFS root
+ * server from where we'll start following any referrals.  Otherwise rely on the
+ * value provided by mount(2) as the user might not have dns_resolver key set up
+ * and therefore failing to upcall to resolve UNC hostname under @ctx->source.
+ */
+static int update_fs_context_dstaddr(struct smb3_fs_context *ctx)
+{
+	struct sockaddr *addr = (struct sockaddr *)&ctx->dstaddr;
+	int rc = 0;
+
+	if (!ctx->nodfs && ctx->dfs_automount) {
+		rc = dns_resolve_unc(NULL, ctx->source, addr);
+		if (!rc)
+			cifs_set_port(addr, ctx->port);
+		ctx->dfs_automount = false;
+	}
+	return rc;
+}
+
+int dfs_mount_share(struct cifs_mount_ctx *mnt_ctx)
+{
+	struct smb3_fs_context *ctx = mnt_ctx->fs_ctx;
+	bool nodfs = ctx->nodfs;
+	int rc;
+
+	rc = update_fs_context_dstaddr(ctx);
+	if (rc)
+		return rc;
+
+	rc = get_session(mnt_ctx, NULL);
+	if (rc)
+		return rc;
+
+	/*
+	 * If called with 'nodfs' mount option, then skip DFS resolving.  Otherwise unconditionally
+	 * try to get an DFS referral (even cached) to determine whether it is an DFS mount.
+	 *
+	 * Skip prefix path to provide support for DFS referrals from w2k8 servers which don't seem
+	 * to respond with PATH_NOT_COVERED to requests that include the prefix.
+	 */
+	if (!nodfs) {
+		rc = dfs_get_referral(mnt_ctx, ctx->UNC + 1, NULL);
+		if (rc) {
+			cifs_dbg(FYI, "%s: no dfs referral for %s: %d\n",
+				 __func__, ctx->UNC + 1, rc);
+			cifs_dbg(FYI, "%s: assuming non-dfs mount...\n", __func__);
+			nodfs = true;
+		}
+	}
+	if (nodfs) {
+		rc = cifs_mount_get_tcon(mnt_ctx);
+		if (!rc)
+			rc = cifs_is_path_remote(mnt_ctx);
+		return rc;
+	}
+
+	if (!ctx->dfs_conn) {
+		ctx->dfs_conn = true;
+		cifs_mount_put_conns(mnt_ctx);
+		rc = get_session(mnt_ctx, NULL);
+	}
+	if (!rc)
+		rc = __dfs_mount_share(mnt_ctx);
+	return rc;
+}
+
+static int target_share_matches_server(struct TCP_Server_Info *server, char *share,
+				       bool *target_match)
+{
+	int rc = 0;
+	const char *dfs_host;
+	size_t dfs_host_len;
+
+	*target_match = true;
+	extract_unc_hostname(share, &dfs_host, &dfs_host_len);
+
+	/* Check if hostnames or addresses match */
+	cifs_server_lock(server);
+	if (dfs_host_len != strlen(server->hostname) ||
+	    strncasecmp(dfs_host, server->hostname, dfs_host_len)) {
+		cifs_dbg(FYI, "%s: %.*s doesn't match %s\n", __func__,
+			 (int)dfs_host_len, dfs_host, server->hostname);
+		rc = match_target_ip(server, dfs_host, dfs_host_len, target_match);
+		if (rc)
+			cifs_dbg(VFS, "%s: failed to match target ip: %d\n", __func__, rc);
+	}
+	cifs_server_unlock(server);
+	return rc;
+}
+
+static int tree_connect_dfs_target(const unsigned int xid,
+				   struct cifs_tcon *tcon,
+				   struct cifs_sb_info *cifs_sb,
+				   char *tree, bool islink,
+				   struct dfs_cache_tgt_list *tl)
+{
+	const struct smb_version_operations *ops = tcon->ses->server->ops;
+	struct TCP_Server_Info *server = tcon->ses->server;
+	struct dfs_cache_tgt_iterator *tit;
+	char *share = NULL, *prefix = NULL;
+	bool target_match;
+	int rc = -ENOENT;
+
+	/* Try to tree connect to all dfs targets */
+	for (tit = dfs_cache_get_tgt_iterator(tl);
+	     tit; tit = dfs_cache_get_next_tgt(tl, tit)) {
+		kfree(share);
+		kfree(prefix);
+		share = prefix = NULL;
+
+		/* Check if share matches with tcp ses */
+		rc = dfs_cache_get_tgt_share(server->leaf_fullpath + 1, tit, &share, &prefix);
+		if (rc) {
+			cifs_dbg(VFS, "%s: failed to parse target share: %d\n", __func__, rc);
+			break;
+		}
+
+		rc = target_share_matches_server(server, share, &target_match);
+		if (rc)
+			break;
+		if (!target_match) {
+			rc = -EHOSTUNREACH;
+			continue;
+		}
+
+		dfs_cache_noreq_update_tgthint(server->leaf_fullpath + 1, tit);
+		scnprintf(tree, MAX_TREE_SIZE, "\\%s", share);
+		rc = ops->tree_connect(xid, tcon->ses, tree,
+				       tcon, tcon->ses->local_nls);
+		if (islink && !rc && cifs_sb)
+			rc = cifs_update_super_prepath(cifs_sb, prefix);
+		break;
+	}
+
+	kfree(share);
+	kfree(prefix);
+	dfs_cache_free_tgts(tl);
+	return rc;
+}
+
+int cifs_tree_connect(const unsigned int xid, struct cifs_tcon *tcon)
+{
+	int rc;
+	struct TCP_Server_Info *server = tcon->ses->server;
+	const struct smb_version_operations *ops = server->ops;
+	DFS_CACHE_TGT_LIST(tl);
+	struct cifs_sb_info *cifs_sb = NULL;
+	struct super_block *sb = NULL;
+	struct dfs_info3_param ref = {0};
+	char *tree;
+
+	/* only send once per connect */
+	spin_lock(&tcon->tc_lock);
+
+	/* if tcon is marked for needing reconnect, update state */
+	if (tcon->need_reconnect)
+		tcon->status = TID_NEED_TCON;
+
+	if (tcon->status == TID_GOOD) {
+		spin_unlock(&tcon->tc_lock);
+		return 0;
+	}
+
+	if (tcon->status != TID_NEW &&
+	    tcon->status != TID_NEED_TCON) {
+		spin_unlock(&tcon->tc_lock);
+		return -EHOSTDOWN;
+	}
+
+	tcon->status = TID_IN_TCON;
+	spin_unlock(&tcon->tc_lock);
+
+	tree = kzalloc(MAX_TREE_SIZE, GFP_KERNEL);
+	if (!tree) {
+		rc = -ENOMEM;
+		goto out;
+	}
+
+	if (tcon->ipc) {
+		cifs_server_lock(server);
+		scnprintf(tree, MAX_TREE_SIZE, "\\\\%s\\IPC$", server->hostname);
+		cifs_server_unlock(server);
+		rc = ops->tree_connect(xid, tcon->ses, tree,
+				       tcon, tcon->ses->local_nls);
+		goto out;
+	}
+
+	sb = cifs_get_dfs_tcon_super(tcon);
+	if (!IS_ERR(sb))
+		cifs_sb = CIFS_SB(sb);
+
+	/* Tree connect to last share in @tcon->tree_name if no DFS referral */
+	if (!server->leaf_fullpath ||
+	    dfs_cache_noreq_find(server->leaf_fullpath + 1, &ref, &tl)) {
+		rc = ops->tree_connect(xid, tcon->ses, tcon->tree_name,
+				       tcon, tcon->ses->local_nls);
+		goto out;
+	}
+
+	rc = tree_connect_dfs_target(xid, tcon, cifs_sb, tree, ref.server_type == DFS_TYPE_LINK,
+				     &tl);
+	free_dfs_info_param(&ref);
+
+out:
+	kfree(tree);
+	cifs_put_tcp_super(sb);
+
+	if (rc) {
+		spin_lock(&tcon->tc_lock);
+		if (tcon->status == TID_IN_TCON)
+			tcon->status = TID_NEED_TCON;
+		spin_unlock(&tcon->tc_lock);
+	} else {
+		spin_lock(&tcon->tc_lock);
+		if (tcon->status == TID_IN_TCON)
+			tcon->status = TID_GOOD;
+		tcon->need_reconnect = false;
+		spin_unlock(&tcon->tc_lock);
+	}
+
+	return rc;
+}