[PATCH v3] ksmbd: use LOOKUP_BENEATH to prevent the out of share access

[Hyunchul Lee <hyc.lee@gmail.com>]

instead of removing '..' in a given path, call
kern_path with LOOKUP_BENEATH flag to prevent
the out of share access.

ran various test on this:
smb2-cat-async smb://127.0.0.1/homes/../out_of_share
smb2-cat-async smb://127.0.0.1/homes/foo/../../out_of_share
smbclient //127.0.0.1/homes -c "mkdir ../foo2"
smbclient //127.0.0.1/homes -c "rename bar ../bar"

Cc: Ronnie Sahlberg <ronniesahlberg@gmail.com>
Cc: Ralph Boehme <slow@samba.org>
Cc: Steve French <smfrench@gmail.com>
Cc: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Hyunchul Lee <hyc.lee@gmail.com>
---
Changes from v1:
 - pass path of file that is relative to share to ksmbd vfs functions.
Changes from v2:
 - fix smbtorture smb2.streams.rename, smb2.streams.rename2 failure

 fs/ksmbd/misc.c    | 100 ++++++----------------------
 fs/ksmbd/misc.h    |   7 +-
 fs/ksmbd/smb2pdu.c |  74 ++++++++-------------
 fs/ksmbd/vfs.c     | 162 ++++++++++++++++++++++++---------------------
 fs/ksmbd/vfs.h     |   9 ++-
 5 files changed, 143 insertions(+), 209 deletions(-)

diff --git a/fs/ksmbd/misc.c b/fs/ksmbd/misc.c
index 3eac3c01749f..6a19f4bc692d 100644
--- a/fs/ksmbd/misc.c
+++ b/fs/ksmbd/misc.c
@@ -158,25 +158,21 @@ int parse_stream_name(char *filename, char **stream_name, int *s_type)
  * Return : windows path string or error
  */
 
-char *convert_to_nt_pathname(char *filename, char *sharepath)
+char *convert_to_nt_pathname(char *filename)
 {
 	char *ab_pathname;
-	int len, name_len;
 
-	name_len = strlen(filename);
-	ab_pathname = kmalloc(name_len, GFP_KERNEL);
-	if (!ab_pathname)
-		return NULL;
-
-	ab_pathname[0] = '\\';
-	ab_pathname[1] = '\0';
+	if (strlen(filename) == 0) {
+		ab_pathname = kmalloc(2, GFP_KERNEL);
+		ab_pathname[0] = '\\';
+		ab_pathname[1] = '\0';
+	} else {
+		ab_pathname = kstrdup(filename, GFP_KERNEL);
+		if (!ab_pathname)
+			return NULL;
 
-	len = strlen(sharepath);
-	if (!strncmp(filename, sharepath, len) && name_len != len) {
-		strscpy(ab_pathname, &filename[len], name_len);
 		ksmbd_conv_path_to_windows(ab_pathname);
 	}
-
 	return ab_pathname;
 }
 
@@ -191,77 +187,19 @@ int get_nlink(struct kstat *st)
 	return nlink;
 }
 
-char *ksmbd_conv_path_to_unix(char *path)
+void ksmbd_conv_path_to_unix(char *path)
 {
-	size_t path_len, remain_path_len, out_path_len;
-	char *out_path, *out_next;
-	int i, pre_dotdot_cnt = 0, slash_cnt = 0;
-	bool is_last;
-
 	strreplace(path, '\\', '/');
-	path_len = strlen(path);
-	remain_path_len = path_len;
-	if (path_len == 0)
-		return ERR_PTR(-EINVAL);
-
-	out_path = kzalloc(path_len + 2, GFP_KERNEL);
-	if (!out_path)
-		return ERR_PTR(-ENOMEM);
-	out_path_len = 0;
-	out_next = out_path;
-
-	do {
-		char *name = path + path_len - remain_path_len;
-		char *next = strchrnul(name, '/');
-		size_t name_len = next - name;
-
-		is_last = !next[0];
-		if (name_len == 2 && name[0] == '.' && name[1] == '.') {
-			pre_dotdot_cnt++;
-			/* handle the case that path ends with "/.." */
-			if (is_last)
-				goto follow_dotdot;
-		} else {
-			if (pre_dotdot_cnt) {
-follow_dotdot:
-				slash_cnt = 0;
-				for (i = out_path_len - 1; i >= 0; i--) {
-					if (out_path[i] == '/' &&
-					    ++slash_cnt == pre_dotdot_cnt + 1)
-						break;
-				}
-
-				if (i < 0 &&
-				    slash_cnt != pre_dotdot_cnt) {
-					kfree(out_path);
-					return ERR_PTR(-EINVAL);
-				}
-
-				out_next = &out_path[i+1];
-				*out_next = '\0';
-				out_path_len = i + 1;
-
-			}
-
-			if (name_len != 0 &&
-			    !(name_len == 1 && name[0] == '.') &&
-			    !(name_len == 2 && name[0] == '.' && name[1] == '.')) {
-				next[0] = '\0';
-				sprintf(out_next, "%s/", name);
-				out_next += name_len + 1;
-				out_path_len += name_len + 1;
-				next[0] = '/';
-			}
-			pre_dotdot_cnt = 0;
-		}
+}
 
-		remain_path_len -= name_len + 1;
-	} while (!is_last);
+void ksmbd_strip_last_slash(char *path)
+{
+	int len = strlen(path);
 
-	if (out_path_len > 0)
-		out_path[out_path_len-1] = '\0';
-	path[path_len] = '\0';
-	return out_path;
+	while (len && path[len - 1] == '/') {
+		path[len - 1] = '\0';
+		len--;
+	}
 }
 
 void ksmbd_conv_path_to_windows(char *path)
@@ -298,7 +236,7 @@ char *ksmbd_extract_sharename(char *treename)
  *
  * Return:	converted name on success, otherwise NULL
  */
-char *convert_to_unix_name(struct ksmbd_share_config *share, char *name)
+char *convert_to_unix_name(struct ksmbd_share_config *share, const char *name)
 {
 	int no_slash = 0, name_len, path_len;
 	char *new_name;
diff --git a/fs/ksmbd/misc.h b/fs/ksmbd/misc.h
index b7b10139ada2..253366bd0951 100644
--- a/fs/ksmbd/misc.h
+++ b/fs/ksmbd/misc.h
@@ -14,12 +14,13 @@ struct ksmbd_file;
 int match_pattern(const char *str, size_t len, const char *pattern);
 int ksmbd_validate_filename(char *filename);
 int parse_stream_name(char *filename, char **stream_name, int *s_type);
-char *convert_to_nt_pathname(char *filename, char *sharepath);
+char *convert_to_nt_pathname(char *filename);
 int get_nlink(struct kstat *st);
-char *ksmbd_conv_path_to_unix(char *path);
+void ksmbd_conv_path_to_unix(char *path);
+void ksmbd_strip_last_slash(char *path);
 void ksmbd_conv_path_to_windows(char *path);
 char *ksmbd_extract_sharename(char *treename);
-char *convert_to_unix_name(struct ksmbd_share_config *share, char *name);
+char *convert_to_unix_name(struct ksmbd_share_config *share, const char *name);
 
 #define KSMBD_DIR_INFO_ALIGNMENT	8
 struct ksmbd_dir_info;
diff --git a/fs/ksmbd/smb2pdu.c b/fs/ksmbd/smb2pdu.c
index 9f45779c5f95..bb39b18a6673 100644
--- a/fs/ksmbd/smb2pdu.c
+++ b/fs/ksmbd/smb2pdu.c
@@ -643,7 +643,7 @@ static char *
 smb2_get_name(struct ksmbd_share_config *share, const char *src,
 	      const int maxlen, struct nls_table *local_nls)
 {
-	char *name, *norm_name, *unixname;
+	char *name;
 
 	name = smb_strndup_from_utf16(src, maxlen, 1, local_nls);
 	if (IS_ERR(name)) {
@@ -651,23 +651,9 @@ smb2_get_name(struct ksmbd_share_config *share, const char *src,
 		return name;
 	}
 
-	/* change it to absolute unix name */
-	norm_name = ksmbd_conv_path_to_unix(name);
-	if (IS_ERR(norm_name)) {
-		kfree(name);
-		return norm_name;
-	}
-	kfree(name);
-
-	unixname = convert_to_unix_name(share, norm_name);
-	kfree(norm_name);
-	if (!unixname) {
-		pr_err("can not convert absolute name\n");
-		return ERR_PTR(-ENOMEM);
-	}
-
-	ksmbd_debug(SMB, "absolute name = %s\n", unixname);
-	return unixname;
+	ksmbd_conv_path_to_unix(name);
+	ksmbd_strip_last_slash(name);
+	return name;
 }
 
 int setup_async_work(struct ksmbd_work *work, void (*fn)(void **), void **arg)
@@ -2412,7 +2398,7 @@ static int smb2_creat(struct ksmbd_work *work, struct path *path, char *name,
 			return rc;
 	}
 
-	rc = ksmbd_vfs_kern_path(name, 0, path, 0);
+	rc = ksmbd_vfs_kern_path(work, name, 0, path, 0);
 	if (rc) {
 		pr_err("cannot get linux path (%s), err = %d\n",
 		       name, rc);
@@ -2487,7 +2473,7 @@ int smb2_open(struct ksmbd_work *work)
 	struct oplock_info *opinfo;
 	__le32 *next_ptr = NULL;
 	int req_op_level = 0, open_flags = 0, may_flags = 0, file_info = 0;
-	int rc = 0, len = 0;
+	int rc = 0;
 	int contxt_cnt = 0, query_disk_id = 0;
 	int maximal_access_ctxt = 0, posix_ctxt = 0;
 	int s_type = 0;
@@ -2559,17 +2545,11 @@ int smb2_open(struct ksmbd_work *work)
 			goto err_out1;
 		}
 	} else {
-		len = strlen(share->path);
-		ksmbd_debug(SMB, "share path len %d\n", len);
-		name = kmalloc(len + 1, GFP_KERNEL);
+		name = kstrdup("", GFP_KERNEL);
 		if (!name) {
-			rsp->hdr.Status = STATUS_NO_MEMORY;
 			rc = -ENOMEM;
 			goto err_out1;
 		}
-
-		memcpy(name, share->path, len);
-		*(name + len) = '\0';
 	}
 
 	req_op_level = req->RequestedOplockLevel;
@@ -2692,7 +2672,7 @@ int smb2_open(struct ksmbd_work *work)
 		goto err_out1;
 	}
 
-	rc = ksmbd_vfs_kern_path(name, LOOKUP_NO_SYMLINKS, &path, 1);
+	rc = ksmbd_vfs_kern_path(work, name, LOOKUP_NO_SYMLINKS, &path, 1);
 	if (!rc) {
 		if (req->CreateOptions & FILE_DELETE_ON_CLOSE_LE) {
 			/*
@@ -2721,11 +2701,8 @@ int smb2_open(struct ksmbd_work *work)
 	}
 
 	if (rc) {
-		if (rc == -EACCES) {
-			ksmbd_debug(SMB,
-				    "User does not have right permission\n");
+		if (rc != -ENOENT)
 			goto err_out;
-		}
 		ksmbd_debug(SMB, "can not get linux path for %s, rc = %d\n",
 			    name, rc);
 		rc = 0;
@@ -3229,7 +3206,7 @@ int smb2_open(struct ksmbd_work *work)
 			rsp->hdr.Status = STATUS_INVALID_PARAMETER;
 		else if (rc == -EOPNOTSUPP)
 			rsp->hdr.Status = STATUS_NOT_SUPPORTED;
-		else if (rc == -EACCES || rc == -ESTALE)
+		else if (rc == -EACCES || rc == -ESTALE || rc == -EXDEV)
 			rsp->hdr.Status = STATUS_ACCESS_DENIED;
 		else if (rc == -ENOENT)
 			rsp->hdr.Status = STATUS_OBJECT_NAME_INVALID;
@@ -4345,8 +4322,7 @@ static int get_file_all_info(struct ksmbd_work *work,
 		return -EACCES;
 	}
 
-	filename = convert_to_nt_pathname(fp->filename,
-					  work->tcon->share_conf->path);
+	filename = convert_to_nt_pathname(fp->filename);
 	if (!filename)
 		return -ENOMEM;
 
@@ -4801,7 +4777,7 @@ static int smb2_get_info_filesystem(struct ksmbd_work *work,
 	int rc = 0, len;
 	int fs_infoclass_size = 0;
 
-	rc = ksmbd_vfs_kern_path(share->path, LOOKUP_NO_SYMLINKS, &path, 0);
+	rc = kern_path(share->path, LOOKUP_NO_SYMLINKS, &path);
 	if (rc) {
 		pr_err("cannot create vfs path\n");
 		return -EIO;
@@ -5350,7 +5326,7 @@ static int smb2_rename(struct ksmbd_work *work,
 			goto out;
 
 		len = strlen(new_name);
-		if (new_name[len - 1] != '/') {
+		if (len > 0 && new_name[len - 1] != '/') {
 			pr_err("not allow base filename in rename\n");
 			rc = -ESHARE;
 			goto out;
@@ -5378,11 +5354,14 @@ static int smb2_rename(struct ksmbd_work *work,
 	}
 
 	ksmbd_debug(SMB, "new name %s\n", new_name);
-	rc = ksmbd_vfs_kern_path(new_name, LOOKUP_NO_SYMLINKS, &path, 1);
-	if (rc)
+	rc = ksmbd_vfs_kern_path(work, new_name, LOOKUP_NO_SYMLINKS, &path, 1);
+	if (rc) {
+		if (rc != -ENOENT)
+			goto out;
 		file_present = false;
-	else
+	} else {
 		path_put(&path);
+	}
 
 	if (ksmbd_share_veto_filename(share, new_name)) {
 		rc = -ENOENT;
@@ -5456,11 +5435,14 @@ static int smb2_create_link(struct ksmbd_work *work,
 	}
 
 	ksmbd_debug(SMB, "target name is %s\n", target_name);
-	rc = ksmbd_vfs_kern_path(link_name, LOOKUP_NO_SYMLINKS, &path, 0);
-	if (rc)
+	rc = ksmbd_vfs_kern_path(work, link_name, LOOKUP_NO_SYMLINKS, &path, 0);
+	if (rc) {
+		if (rc != -ENOENT)
+			goto out;
 		file_present = false;
-	else
+	} else {
 		path_put(&path);
+	}
 
 	if (file_info->ReplaceIfExists) {
 		if (file_present) {
@@ -5618,7 +5600,7 @@ static int set_file_allocation_info(struct ksmbd_work *work,
 		 * inode size is retained by backup inode size.
 		 */
 		size = i_size_read(inode);
-		rc = ksmbd_vfs_truncate(work, NULL, fp, alloc_blks * 512);
+		rc = ksmbd_vfs_truncate(work, fp, alloc_blks * 512);
 		if (rc) {
 			pr_err("truncate failed! filename : %s, err %d\n",
 			       fp->filename, rc);
@@ -5653,7 +5635,7 @@ static int set_end_of_file_info(struct ksmbd_work *work, struct ksmbd_file *fp,
 	if (inode->i_sb->s_magic != MSDOS_SUPER_MAGIC) {
 		ksmbd_debug(SMB, "filename : %s truncated to newsize %lld\n",
 			    fp->filename, newsize);
-		rc = ksmbd_vfs_truncate(work, NULL, fp, newsize);
+		rc = ksmbd_vfs_truncate(work, fp, newsize);
 		if (rc) {
 			ksmbd_debug(SMB, "truncate failed! filename : %s err %d\n",
 				    fp->filename, rc);
@@ -5975,7 +5957,7 @@ int smb2_set_info(struct ksmbd_work *work)
 	return 0;
 
 err_out:
-	if (rc == -EACCES || rc == -EPERM)
+	if (rc == -EACCES || rc == -EPERM || rc == -EXDEV)
 		rsp->hdr.Status = STATUS_ACCESS_DENIED;
 	else if (rc == -EINVAL)
 		rsp->hdr.Status = STATUS_INVALID_PARAMETER;
diff --git a/fs/ksmbd/vfs.c b/fs/ksmbd/vfs.c
index 3733e4944c1d..809b6daf1fff 100644
--- a/fs/ksmbd/vfs.c
+++ b/fs/ksmbd/vfs.c
@@ -19,6 +19,8 @@
 #include <linux/sched/xacct.h>
 #include <linux/crc32c.h>
 
+#include "../internal.h"	/* for vfs_path_lookup */
+
 #include "glob.h"
 #include "oplock.h"
 #include "connection.h"
@@ -44,7 +46,6 @@ static char *extract_last_component(char *path)
 		p++;
 	} else {
 		p = NULL;
-		pr_err("Invalid path %s\n", path);
 	}
 	return p;
 }
@@ -155,7 +156,7 @@ int ksmbd_vfs_query_maximal_access(struct user_namespace *user_ns,
 /**
  * ksmbd_vfs_create() - vfs helper for smb create file
  * @work:	work
- * @name:	file name
+ * @name:	file name that is relative to share
  * @mode:	file create mode
  *
  * Return:	0 on success, otherwise error
@@ -166,7 +167,8 @@ int ksmbd_vfs_create(struct ksmbd_work *work, const char *name, umode_t mode)
 	struct dentry *dentry;
 	int err;
 
-	dentry = kern_path_create(AT_FDCWD, name, &path, LOOKUP_NO_SYMLINKS);
+	dentry = ksmbd_vfs_kern_path_create(work, name,
+					    LOOKUP_NO_SYMLINKS, &path);
 	if (IS_ERR(dentry)) {
 		err = PTR_ERR(dentry);
 		if (err != -ENOENT)
@@ -191,7 +193,7 @@ int ksmbd_vfs_create(struct ksmbd_work *work, const char *name, umode_t mode)
 /**
  * ksmbd_vfs_mkdir() - vfs helper for smb create directory
  * @work:	work
- * @name:	directory name
+ * @name:	directory name that is relative to share
  * @mode:	directory create mode
  *
  * Return:	0 on success, otherwise error
@@ -203,8 +205,9 @@ int ksmbd_vfs_mkdir(struct ksmbd_work *work, const char *name, umode_t mode)
 	struct dentry *dentry;
 	int err;
 
-	dentry = kern_path_create(AT_FDCWD, name, &path,
-				  LOOKUP_NO_SYMLINKS | LOOKUP_DIRECTORY);
+	dentry = ksmbd_vfs_kern_path_create(work, name,
+					    LOOKUP_NO_SYMLINKS | LOOKUP_DIRECTORY,
+					    &path);
 	if (IS_ERR(dentry)) {
 		err = PTR_ERR(dentry);
 		if (err != -EEXIST)
@@ -579,7 +582,7 @@ int ksmbd_vfs_fsync(struct ksmbd_work *work, u64 fid, u64 p_id)
 
 /**
  * ksmbd_vfs_remove_file() - vfs helper for smb rmdir or unlink
- * @name:	absolute directory or file name
+ * @name:	directory or file name that is relative to share
  *
  * Return:	0 on success, otherwise error
  */
@@ -593,7 +596,7 @@ int ksmbd_vfs_remove_file(struct ksmbd_work *work, char *name)
 	if (ksmbd_override_fsids(work))
 		return -ENOMEM;
 
-	err = kern_path(name, LOOKUP_NO_SYMLINKS, &path);
+	err = ksmbd_vfs_kern_path(work, name, LOOKUP_NO_SYMLINKS, &path, false);
 	if (err) {
 		ksmbd_debug(VFS, "can't get %s, err %d\n", name, err);
 		ksmbd_revert_fsids(work);
@@ -638,7 +641,7 @@ int ksmbd_vfs_remove_file(struct ksmbd_work *work, char *name)
 /**
  * ksmbd_vfs_link() - vfs helper for creating smb hardlink
  * @oldname:	source file name
- * @newname:	hardlink name
+ * @newname:	hardlink name that is relative to share
  *
  * Return:	0 on success, otherwise error
  */
@@ -659,8 +662,9 @@ int ksmbd_vfs_link(struct ksmbd_work *work, const char *oldname,
 		goto out1;
 	}
 
-	dentry = kern_path_create(AT_FDCWD, newname, &newpath,
-				  LOOKUP_NO_SYMLINKS | LOOKUP_REVAL);
+	dentry = ksmbd_vfs_kern_path_create(work, newname,
+					    LOOKUP_NO_SYMLINKS | LOOKUP_REVAL,
+					    &newpath);
 	if (IS_ERR(dentry)) {
 		err = PTR_ERR(dentry);
 		pr_err("path create err for %s, err %d\n", newname, err);
@@ -781,14 +785,17 @@ int ksmbd_vfs_fp_rename(struct ksmbd_work *work, struct ksmbd_file *fp,
 	int err;
 
 	dst_name = extract_last_component(newname);
-	if (!dst_name)
-		return -EINVAL;
+	if (!dst_name) {
+		dst_name = newname;
+		newname = "";
+	}
 
 	src_dent_parent = dget_parent(fp->filp->f_path.dentry);
 	src_dent = fp->filp->f_path.dentry;
 
-	err = kern_path(newname, LOOKUP_NO_SYMLINKS | LOOKUP_DIRECTORY,
-			&dst_path);
+	err = ksmbd_vfs_kern_path(work, newname,
+				  LOOKUP_NO_SYMLINKS | LOOKUP_DIRECTORY,
+				  &dst_path, false);
 	if (err) {
 		ksmbd_debug(VFS, "Cannot get path for %s [%d]\n", newname, err);
 		goto out;
@@ -834,61 +841,43 @@ int ksmbd_vfs_fp_rename(struct ksmbd_work *work, struct ksmbd_file *fp,
 /**
  * ksmbd_vfs_truncate() - vfs helper for smb file truncate
  * @work:	work
- * @name:	old filename
  * @fid:	file id of old file
  * @size:	truncate to given size
  *
  * Return:	0 on success, otherwise error
  */
-int ksmbd_vfs_truncate(struct ksmbd_work *work, const char *name,
+int ksmbd_vfs_truncate(struct ksmbd_work *work,
 		       struct ksmbd_file *fp, loff_t size)
 {
-	struct path path;
 	int err = 0;
+	struct file *filp;
 
-	if (name) {
-		err = kern_path(name, LOOKUP_NO_SYMLINKS, &path);
-		if (err) {
-			pr_err("cannot get linux path for %s, err %d\n",
-			       name, err);
-			return err;
-		}
-		err = vfs_truncate(&path, size);
-		if (err)
-			pr_err("truncate failed for %s err %d\n",
-			       name, err);
-		path_put(&path);
-	} else {
-		struct file *filp;
-
-		filp = fp->filp;
-
-		/* Do we need to break any of a levelII oplock? */
-		smb_break_all_levII_oplock(work, fp, 1);
+	filp = fp->filp;
 
-		if (!work->tcon->posix_extensions) {
-			struct inode *inode = file_inode(filp);
+	/* Do we need to break any of a levelII oplock? */
+	smb_break_all_levII_oplock(work, fp, 1);
 
-			if (size < inode->i_size) {
-				err = check_lock_range(filp, size,
-						       inode->i_size - 1, WRITE);
-			} else {
-				err = check_lock_range(filp, inode->i_size,
-						       size - 1, WRITE);
-			}
+	if (!work->tcon->posix_extensions) {
+		struct inode *inode = file_inode(filp);
 
-			if (err) {
-				pr_err("failed due to lock\n");
-				return -EAGAIN;
-			}
+		if (size < inode->i_size) {
+			err = check_lock_range(filp, size,
+					       inode->i_size - 1, WRITE);
+		} else {
+			err = check_lock_range(filp, inode->i_size,
+					       size - 1, WRITE);
 		}
 
-		err = vfs_truncate(&filp->f_path, size);
-		if (err)
-			pr_err("truncate failed for filename : %s err %d\n",
-			       fp->filename, err);
+		if (err) {
+			pr_err("failed due to lock\n");
+			return -EAGAIN;
+		}
 	}
 
+	err = vfs_truncate(&filp->f_path, size);
+	if (err)
+		pr_err("truncate failed for filename : %s err %d\n",
+		       fp->filename, err);
 	return err;
 }
 
@@ -1206,27 +1195,30 @@ static int ksmbd_vfs_lookup_in_dir(struct path *dir, char *name, size_t namelen)
 
 /**
  * ksmbd_vfs_kern_path() - lookup a file and get path info
- * @name:	name of file for lookup
+ * @name:	file path that is relative to share
  * @flags:	lookup flags
  * @path:	if lookup succeed, return path info
  * @caseless:	caseless filename lookup
  *
  * Return:	0 on success, otherwise error
  */
-int ksmbd_vfs_kern_path(char *name, unsigned int flags, struct path *path,
-			bool caseless)
+int ksmbd_vfs_kern_path(struct ksmbd_work *work, char *name,
+			unsigned int flags, struct path *path, bool caseless)
 {
+	struct ksmbd_share_config *share_conf = work->tcon->share_conf;
+	char *filepath;
 	int err;
 
-	if (name[0] != '/')
-		return -EINVAL;
-
-	err = kern_path(name, flags, path);
+	flags |= LOOKUP_BENEATH;
+	err = vfs_path_lookup(share_conf->vfs_path.dentry,
+			      share_conf->vfs_path.mnt,
+			      name,
+			      flags,
+			      path);
 	if (!err)
 		return 0;
 
 	if (caseless) {
-		char *filepath;
 		struct path parent;
 		size_t path_len, remain_len;
 
@@ -1235,11 +1227,10 @@ int ksmbd_vfs_kern_path(char *name, unsigned int flags, struct path *path,
 			return -ENOMEM;
 
 		path_len = strlen(filepath);
-		remain_len = path_len - 1;
+		remain_len = path_len;
 
-		err = kern_path("/", flags, &parent);
-		if (err)
-			goto out;
+		parent = share_conf->vfs_path;
+		path_get(&parent);
 
 		while (d_can_lookup(parent.dentry)) {
 			char *filename = filepath + path_len - remain_len;
@@ -1252,21 +1243,21 @@ int ksmbd_vfs_kern_path(char *name, unsigned int flags, struct path *path,
 
 			err = ksmbd_vfs_lookup_in_dir(&parent, filename,
 						      filename_len);
-			if (err) {
-				path_put(&parent);
+			path_put(&parent);
+			if (err)
 				goto out;
-			}
 
-			path_put(&parent);
 			next[0] = '\0';
 
-			err = kern_path(filepath, flags, &parent);
+			err = vfs_path_lookup(share_conf->vfs_path.dentry,
+					      share_conf->vfs_path.mnt,
+					      filepath,
+					      flags,
+					      &parent);
 			if (err)
 				goto out;
-
-			if (is_last) {
-				path->mnt = parent.mnt;
-				path->dentry = parent.dentry;
+			else if (is_last) {
+				*path = parent;
 				goto out;
 			}
 
@@ -1276,12 +1267,29 @@ int ksmbd_vfs_kern_path(char *name, unsigned int flags, struct path *path,
 
 		path_put(&parent);
 		err = -EINVAL;
-out:
-		kfree(filepath);
 	}
+out:
+	kfree(filepath);
 	return err;
 }
 
+struct dentry *ksmbd_vfs_kern_path_create(struct ksmbd_work *work,
+					  const char *name,
+					  unsigned int flags,
+					  struct path *path)
+{
+	char *abs_name;
+	struct dentry *dent;
+
+	abs_name = convert_to_unix_name(work->tcon->share_conf, name);
+	if (!abs_name)
+		return ERR_PTR(-ENOMEM);
+
+	dent = kern_path_create(AT_FDCWD, abs_name, path, flags);
+	kfree(abs_name);
+	return dent;
+}
+
 int ksmbd_vfs_remove_acl_xattrs(struct user_namespace *user_ns,
 				struct dentry *dentry)
 {
diff --git a/fs/ksmbd/vfs.h b/fs/ksmbd/vfs.h
index 85db50abdb24..7b1dcaa3fbdc 100644
--- a/fs/ksmbd/vfs.h
+++ b/fs/ksmbd/vfs.h
@@ -126,7 +126,7 @@ int ksmbd_vfs_link(struct ksmbd_work *work,
 int ksmbd_vfs_getattr(struct path *path, struct kstat *stat);
 int ksmbd_vfs_fp_rename(struct ksmbd_work *work, struct ksmbd_file *fp,
 			char *newname);
-int ksmbd_vfs_truncate(struct ksmbd_work *work, const char *name,
+int ksmbd_vfs_truncate(struct ksmbd_work *work,
 		       struct ksmbd_file *fp, loff_t size);
 struct srv_copychunk;
 int ksmbd_vfs_copy_file_ranges(struct ksmbd_work *work,
@@ -152,8 +152,13 @@ int ksmbd_vfs_xattr_stream_name(char *stream_name, char **xattr_stream_name,
 				size_t *xattr_stream_name_size, int s_type);
 int ksmbd_vfs_remove_xattr(struct user_namespace *user_ns,
 			   struct dentry *dentry, char *attr_name);
-int ksmbd_vfs_kern_path(char *name, unsigned int flags, struct path *path,
+int ksmbd_vfs_kern_path(struct ksmbd_work *work,
+			char *name, unsigned int flags, struct path *path,
 			bool caseless);
+struct dentry *ksmbd_vfs_kern_path_create(struct ksmbd_work *work,
+					  const char *name,
+					  unsigned int flags,
+					  struct path *path);
 int ksmbd_vfs_empty_dir(struct ksmbd_file *fp);
 void ksmbd_vfs_set_fadvise(struct file *filp, __le32 option);
 int ksmbd_vfs_zero_data(struct ksmbd_work *work, struct ksmbd_file *fp,
-- 
2.25.1