Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 262 insertions, 0 deletions

diff --git a/fs/smb/client/namespace.c b/fs/smb/client/namespace.c
new file mode 100644
index 000000000..a6968573b
--- /dev/null
+++ b/fs/smb/client/namespace.c
@@ -0,0 +1,262 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *   Contains mounting routines used for handling traversal via SMB junctions.
+ *
+ *   Copyright (c) 2007 Igor Mammedov
+ *   Copyright (C) International Business Machines  Corp., 2008
+ *   Author(s): Igor Mammedov (niallain@gmail.com)
+ *		Steve French (sfrench@us.ibm.com)
+ *   Copyright (c) 2023 Paulo Alcantara <palcantara@suse.de>
+ */
+
+#include <linux/dcache.h>
+#include <linux/mount.h>
+#include <linux/namei.h>
+#include <linux/slab.h>
+#include <linux/vfs.h>
+#include <linux/fs.h>
+#include <linux/inet.h>
+#include "cifsglob.h"
+#include "cifsproto.h"
+#include "cifsfs.h"
+#include "cifs_debug.h"
+#include "fs_context.h"
+
+static LIST_HEAD(cifs_automount_list);
+
+static void cifs_expire_automounts(struct work_struct *work);
+static DECLARE_DELAYED_WORK(cifs_automount_task,
+			    cifs_expire_automounts);
+static int cifs_mountpoint_expiry_timeout = 500 * HZ;
+
+static void cifs_expire_automounts(struct work_struct *work)
+{
+	struct list_head *list = &cifs_automount_list;
+
+	mark_mounts_for_expiry(list);
+	if (!list_empty(list))
+		schedule_delayed_work(&cifs_automount_task,
+				      cifs_mountpoint_expiry_timeout);
+}
+
+void cifs_release_automount_timer(void)
+{
+	if (WARN_ON(!list_empty(&cifs_automount_list)))
+		return;
+	cancel_delayed_work_sync(&cifs_automount_task);
+}
+
+/**
+ * cifs_build_devname - build a devicename from a UNC and optional prepath
+ * @nodename:	pointer to UNC string
+ * @prepath:	pointer to prefixpath (or NULL if there isn't one)
+ *
+ * Build a new cifs devicename after chasing a DFS referral. Allocate a buffer
+ * big enough to hold the final thing. Copy the UNC from the nodename, and
+ * concatenate the prepath onto the end of it if there is one.
+ *
+ * Returns pointer to the built string, or a ERR_PTR. Caller is responsible
+ * for freeing the returned string.
+ */
+char *
+cifs_build_devname(char *nodename, const char *prepath)
+{
+	size_t pplen;
+	size_t unclen;
+	char *dev;
+	char *pos;
+
+	/* skip over any preceding delimiters */
+	nodename += strspn(nodename, "\\");
+	if (!*nodename)
+		return ERR_PTR(-EINVAL);
+
+	/* get length of UNC and set pos to last char */
+	unclen = strlen(nodename);
+	pos = nodename + unclen - 1;
+
+	/* trim off any trailing delimiters */
+	while (*pos == '\\') {
+		--pos;
+		--unclen;
+	}
+
+	/* allocate a buffer:
+	 * +2 for preceding "//"
+	 * +1 for delimiter between UNC and prepath
+	 * +1 for trailing NULL
+	 */
+	pplen = prepath ? strlen(prepath) : 0;
+	dev = kmalloc(2 + unclen + 1 + pplen + 1, GFP_KERNEL);
+	if (!dev)
+		return ERR_PTR(-ENOMEM);
+
+	pos = dev;
+	/* add the initial "//" */
+	*pos = '/';
+	++pos;
+	*pos = '/';
+	++pos;
+
+	/* copy in the UNC portion from referral */
+	memcpy(pos, nodename, unclen);
+	pos += unclen;
+
+	/* copy the prefixpath remainder (if there is one) */
+	if (pplen) {
+		*pos = '/';
+		++pos;
+		memcpy(pos, prepath, pplen);
+		pos += pplen;
+	}
+
+	/* NULL terminator */
+	*pos = '\0';
+
+	convert_delimiter(dev, '/');
+	return dev;
+}
+
+static bool is_dfs_mount(struct dentry *dentry)
+{
+	struct cifs_sb_info *cifs_sb = CIFS_SB(dentry->d_sb);
+	struct cifs_tcon *tcon = cifs_sb_master_tcon(cifs_sb);
+	bool ret;
+
+	spin_lock(&tcon->tc_lock);
+	ret = !!tcon->origin_fullpath;
+	spin_unlock(&tcon->tc_lock);
+	return ret;
+}
+
+/* Return full path out of a dentry set for automount */
+static char *automount_fullpath(struct dentry *dentry, void *page)
+{
+	struct cifs_sb_info *cifs_sb = CIFS_SB(dentry->d_sb);
+	struct cifs_tcon *tcon = cifs_sb_master_tcon(cifs_sb);
+	size_t len;
+	char *s;
+
+	spin_lock(&tcon->tc_lock);
+	if (!tcon->origin_fullpath) {
+		spin_unlock(&tcon->tc_lock);
+		return build_path_from_dentry_optional_prefix(dentry,
+							      page,
+							      true);
+	}
+	spin_unlock(&tcon->tc_lock);
+
+	s = dentry_path_raw(dentry, page, PATH_MAX);
+	if (IS_ERR(s))
+		return s;
+	/* for root, we want "" */
+	if (!s[1])
+		s++;
+
+	spin_lock(&tcon->tc_lock);
+	len = strlen(tcon->origin_fullpath);
+	if (s < (char *)page + len) {
+		spin_unlock(&tcon->tc_lock);
+		return ERR_PTR(-ENAMETOOLONG);
+	}
+
+	s -= len;
+	memcpy(s, tcon->origin_fullpath, len);
+	spin_unlock(&tcon->tc_lock);
+	convert_delimiter(s, '/');
+
+	return s;
+}
+
+/*
+ * Create a vfsmount that we can automount
+ */
+static struct vfsmount *cifs_do_automount(struct path *path)
+{
+	int rc;
+	struct dentry *mntpt = path->dentry;
+	struct fs_context *fc;
+	void *page = NULL;
+	struct smb3_fs_context *ctx, *cur_ctx;
+	struct smb3_fs_context tmp;
+	char *full_path;
+	struct vfsmount *mnt;
+
+	if (IS_ROOT(mntpt))
+		return ERR_PTR(-ESTALE);
+
+	cur_ctx = CIFS_SB(mntpt->d_sb)->ctx;
+
+	fc = fs_context_for_submount(path->mnt->mnt_sb->s_type, mntpt);
+	if (IS_ERR(fc))
+		return ERR_CAST(fc);
+
+	ctx = smb3_fc2context(fc);
+
+	page = alloc_dentry_path();
+	full_path = automount_fullpath(mntpt, page);
+	if (IS_ERR(full_path)) {
+		mnt = ERR_CAST(full_path);
+		goto out;
+	}
+
+	tmp = *cur_ctx;
+	tmp.source = NULL;
+	tmp.leaf_fullpath = NULL;
+	tmp.UNC = tmp.prepath = NULL;
+	tmp.dfs_root_ses = NULL;
+
+	rc = smb3_fs_context_dup(ctx, &tmp);
+	if (rc) {
+		mnt = ERR_PTR(rc);
+		goto out;
+	}
+
+	rc = smb3_parse_devname(full_path, ctx);
+	if (rc) {
+		mnt = ERR_PTR(rc);
+		goto out;
+	}
+
+	ctx->source = smb3_fs_context_fullpath(ctx, '/');
+	if (IS_ERR(ctx->source)) {
+		mnt = ERR_CAST(ctx->source);
+		ctx->source = NULL;
+		goto out;
+	}
+	ctx->dfs_automount = is_dfs_mount(mntpt);
+	cifs_dbg(FYI, "%s: ctx: source=%s UNC=%s prepath=%s dfs_automount=%d\n",
+		 __func__, ctx->source, ctx->UNC, ctx->prepath, ctx->dfs_automount);
+
+	mnt = fc_mount(fc);
+out:
+	put_fs_context(fc);
+	free_dentry_path(page);
+	return mnt;
+}
+
+/*
+ * Attempt to automount the referral
+ */
+struct vfsmount *cifs_d_automount(struct path *path)
+{
+	struct vfsmount *newmnt;
+
+	cifs_dbg(FYI, "%s: %pd\n", __func__, path->dentry);
+
+	newmnt = cifs_do_automount(path);
+	if (IS_ERR(newmnt)) {
+		cifs_dbg(FYI, "leaving %s [automount failed]\n" , __func__);
+		return newmnt;
+	}
+
+	mntget(newmnt); /* prevent immediate expiration */
+	mnt_set_expiry(newmnt, &cifs_automount_list);
+	schedule_delayed_work(&cifs_automount_task,
+			      cifs_mountpoint_expiry_timeout);
+	cifs_dbg(FYI, "leaving %s [ok]\n" , __func__);
+	return newmnt;
+}
+
+const struct inode_operations cifs_namespace_inode_operations = {
+};