From 00c743264e4a1cc632b6a43be04c65845122ed84 Mon Sep 17 00:00:00 2001
From: Steve French <stfrench@microsoft.com>
Date: Thu, 22 Oct 2020 22:03:14 -0500
Subject: [PATCH] smb3: add support for stat of WSL reparse points for special
 file types
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

This is needed so when mounting to Windows we do not
misinterpret various special files created by Linux (WSL) as symlinks

With this patch:
  File: /mnt1/char
  Size: 0          Blocks: 0          IO Block: 16384  character special file
Device: 34h/52d Inode: 844424930132069  Links: 1     Device type: 0,0
Access: (0755/crwxr-xr-x)  Uid: (    0/    root)   Gid: (    0/    root)
Access: 2020-10-21 17:46:51.839458900 -0500
Modify: 2020-10-21 17:46:51.839458900 -0500
Change: 2020-10-21 18:30:39.797358800 -0500
 Birth: -
  File: /mnt1/fifo
  Size: 0          Blocks: 0          IO Block: 16384  fifo
Device: 34h/52d Inode: 1125899906842722  Links: 1
Access: (0755/prwxr-xr-x)  Uid: (    0/    root)   Gid: (    0/    root)
Access: 2020-10-21 16:21:37.259249700 -0500
Modify: 2020-10-21 16:21:37.259249700 -0500
Change: 2020-10-21 18:30:39.797358800 -0500
 Birth: -
  File: /mnt1/block
  Size: 0          Blocks: 0          IO Block: 16384  block special file
Device: 34h/52d Inode: 844424930132068  Links: 1     Device type: 0,0
Access: (0755/brwxr-xr-x)  Uid: (    0/    root)   Gid: (    0/    root)
Access: 2020-10-21 17:10:47.913103200 -0500
Modify: 2020-10-21 17:10:47.913103200 -0500
Change: 2020-10-21 18:30:39.796725500 -0500
 Birth: -

without the patch all show up incorrectly as symlinks with annoying "operation not supported error also returned"
  File: /mnt1/charstat: cannot read symbolic link '/mnt1/char': Operation not supported

  Size: 0          Blocks: 0          IO Block: 16384  symbolic link
Device: 34h/52d Inode: 844424930132069  Links: 1
Access: (0000/l---------)  Uid: (    0/    root)   Gid: (    0/    root)
Access: 2020-10-21 17:46:51.839458900 -0500
Modify: 2020-10-21 17:46:51.839458900 -0500
Change: 2020-10-21 18:30:39.797358800 -0500
 Birth: -
  File: /mnt1/fifostat: cannot read symbolic link '/mnt1/fifo': Operation not supported

  Size: 0          Blocks: 0          IO Block: 16384  symbolic link
Device: 34h/52d Inode: 1125899906842722  Links: 1
Access: (0000/l---------)  Uid: (    0/    root)   Gid: (    0/    root)
Access: 2020-10-21 16:21:37.259249700 -0500
Modify: 2020-10-21 16:21:37.259249700 -0500
Change: 2020-10-21 18:30:39.797358800 -0500
 Birth: -
  File: /mnt1/blockstat: cannot read symbolic link '/mnt1/block': Operation not supported

  Size: 0          Blocks: 0          IO Block: 16384  symbolic link
Device: 34h/52d Inode: 844424930132068  Links: 1
Access: (0000/l---------)  Uid: (    0/    root)   Gid: (    0/    root)
Access: 2020-10-21 17:10:47.913103200 -0500
Modify: 2020-10-21 17:10:47.913103200 -0500
Change: 2020-10-21 18:30:39.796725500 -0500

Signed-off-by: Steve French <stfrench@microsoft.com>
---
 fs/cifs/cifsglob.h  |   4 ++
 fs/cifs/inode.c     |  44 ++++++++++++---
 fs/cifs/smb2inode.c |  12 ++--
 fs/cifs/smb2ops.c   | 135 ++++++++++++++++++++++++++++++++++++++++++++
 fs/cifs/smb2pdu.h   |   5 ++
 fs/cifs/smb2proto.h |   3 +
 6 files changed, 189 insertions(+), 14 deletions(-)

diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index b6925aeeb621..484ec2d8c5c9 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -298,6 +298,10 @@ struct smb_version_operations {
 	/* query file data from the server */
 	int (*query_file_info)(const unsigned int, struct cifs_tcon *,
 			       struct cifs_fid *, FILE_ALL_INFO *);
+	/* query reparse tag from srv to determine which type of special file */
+	int (*query_reparse_tag)(const unsigned int xid, struct cifs_tcon *tcon,
+				struct cifs_sb_info *cifs_sb, const char *path,
+				__u32 *reparse_tag);
 	/* get server index number */
 	int (*get_srv_inum)(const unsigned int, struct cifs_tcon *,
 			    struct cifs_sb_info *, const char *,
diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c
index daec31be8571..9ee5f304592f 100644
--- a/fs/cifs/inode.c
+++ b/fs/cifs/inode.c
@@ -656,7 +656,7 @@ smb311_posix_info_to_fattr(struct cifs_fattr *fattr, struct smb311_posix_qinfo *
 static void
 cifs_all_info_to_fattr(struct cifs_fattr *fattr, FILE_ALL_INFO *info,
 		       struct super_block *sb, bool adjust_tz,
-		       bool symlink)
+		       bool symlink, u32 reparse_tag)
 {
 	struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
 	struct cifs_tcon *tcon = cifs_sb_master_tcon(cifs_sb);
@@ -684,8 +684,22 @@ cifs_all_info_to_fattr(struct cifs_fattr *fattr, FILE_ALL_INFO *info,
 	fattr->cf_createtime = le64_to_cpu(info->CreationTime);
 
 	fattr->cf_nlink = le32_to_cpu(info->NumberOfLinks);
-
-	if (symlink) {
+	if (reparse_tag == IO_REPARSE_TAG_LX_SYMLINK) {
+		fattr->cf_mode |= S_IFLNK | cifs_sb->mnt_file_mode;
+		fattr->cf_dtype = DT_LNK;
+	} else if (reparse_tag == IO_REPARSE_TAG_LX_FIFO) {
+		fattr->cf_mode |= S_IFIFO | cifs_sb->mnt_file_mode;
+		fattr->cf_dtype = DT_FIFO;
+	} else if (reparse_tag == IO_REPARSE_TAG_AF_UNIX) {
+		fattr->cf_mode |= S_IFSOCK | cifs_sb->mnt_file_mode;
+		fattr->cf_dtype = DT_SOCK;
+	} else if (reparse_tag == IO_REPARSE_TAG_LX_CHR) {
+		fattr->cf_mode |= S_IFCHR | cifs_sb->mnt_file_mode;
+		fattr->cf_dtype = DT_CHR;
+	} else if (reparse_tag == IO_REPARSE_TAG_LX_BLK) {
+		fattr->cf_mode |= S_IFBLK | cifs_sb->mnt_file_mode;
+		fattr->cf_dtype = DT_BLK;
+	} else if (symlink) { /* TODO add more reparse tag checks */
 		fattr->cf_mode = S_IFLNK;
 		fattr->cf_dtype = DT_LNK;
 	} else if (fattr->cf_cifsattrs & ATTR_DIRECTORY) {
@@ -740,8 +754,9 @@ cifs_get_file_info(struct file *filp)
 	rc = server->ops->query_file_info(xid, tcon, &cfile->fid, &find_data);
 	switch (rc) {
 	case 0:
+		/* TODO: add support to query reparse tag */
 		cifs_all_info_to_fattr(&fattr, &find_data, inode->i_sb, false,
-				       false);
+				       false, 0 /* no reparse tag */);
 		break;
 	case -EREMOTE:
 		cifs_create_dfs_fattr(&fattr, inode->i_sb);
@@ -910,12 +925,13 @@ cifs_get_inode_info(struct inode **inode,
 	struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
 	bool adjust_tz = false;
 	struct cifs_fattr fattr = {0};
-	bool symlink = false;
+	bool is_reparse_point = false;
 	FILE_ALL_INFO *data = in_data;
 	FILE_ALL_INFO *tmp_data = NULL;
 	void *smb1_backup_rsp_buf = NULL;
 	int rc = 0;
 	int tmprc = 0;
+	__u32 reparse_tag = 0;
 
 	tlink = cifs_sb_tlink(cifs_sb);
 	if (IS_ERR(tlink))
@@ -938,8 +954,8 @@ cifs_get_inode_info(struct inode **inode,
 			goto out;
 		}
 		rc = server->ops->query_path_info(xid, tcon, cifs_sb,
-						  full_path, tmp_data,
-						  &adjust_tz, &symlink);
+						 full_path, tmp_data,
+						 &adjust_tz, &is_reparse_point);
 		data = tmp_data;
 	}
 
@@ -949,7 +965,19 @@ cifs_get_inode_info(struct inode **inode,
 
 	switch (rc) {
 	case 0:
-		cifs_all_info_to_fattr(&fattr, data, sb, adjust_tz, symlink);
+		/*
+		 * If the file is a reparse point, it is more complicated
+		 * since we have to check if its reparse tag matches a known
+		 * special file type e.g. symlink or fifo or char etc.
+		 */
+		if ((le32_to_cpu(data->Attributes) & ATTR_REPARSE) &&
+		    server->ops->query_reparse_tag) {
+			rc = server->ops->query_reparse_tag(xid, tcon, cifs_sb,
+						full_path, &reparse_tag);
+			cifs_dbg(FYI, "reparse tag 0x%x\n", reparse_tag);
+		}
+		cifs_all_info_to_fattr(&fattr, data, sb, adjust_tz,
+				       is_reparse_point, reparse_tag);
 		break;
 	case -EREMOTE:
 		/* DFS link, no metadata available on this server */
diff --git a/fs/cifs/smb2inode.c b/fs/cifs/smb2inode.c
index df6212e55e10..1f900b81c34a 100644
--- a/fs/cifs/smb2inode.c
+++ b/fs/cifs/smb2inode.c
@@ -506,7 +506,7 @@ move_smb2_info_to_cifs(FILE_ALL_INFO *dst, struct smb2_file_all_info *src)
 int
 smb2_query_path_info(const unsigned int xid, struct cifs_tcon *tcon,
 		     struct cifs_sb_info *cifs_sb, const char *full_path,
-		     FILE_ALL_INFO *data, bool *adjust_tz, bool *symlink)
+		     FILE_ALL_INFO *data, bool *adjust_tz, bool *reparse)
 {
 	int rc;
 	struct smb2_file_all_info *smb2_data;
@@ -516,7 +516,7 @@ smb2_query_path_info(const unsigned int xid, struct cifs_tcon *tcon,
 	struct cached_fid *cfid = NULL;
 
 	*adjust_tz = false;
-	*symlink = false;
+	*reparse = false;
 
 	smb2_data = kzalloc(sizeof(struct smb2_file_all_info) + PATH_MAX * 2,
 			    GFP_KERNEL);
@@ -548,7 +548,7 @@ smb2_query_path_info(const unsigned int xid, struct cifs_tcon *tcon,
 			      FILE_READ_ATTRIBUTES, FILE_OPEN, create_options,
 			      ACL_NO_MODE, smb2_data, SMB2_OP_QUERY_INFO, cfile);
 	if (rc == -EOPNOTSUPP) {
-		*symlink = true;
+		*reparse = true;
 		create_options |= OPEN_REPARSE_POINT;
 
 		/* Failed on a symbolic link - query a reparse point info */
@@ -570,7 +570,7 @@ smb2_query_path_info(const unsigned int xid, struct cifs_tcon *tcon,
 int
 smb311_posix_query_path_info(const unsigned int xid, struct cifs_tcon *tcon,
 		     struct cifs_sb_info *cifs_sb, const char *full_path,
-		     struct smb311_posix_qinfo *data, bool *adjust_tz, bool *symlink)
+		     struct smb311_posix_qinfo *data, bool *adjust_tz, bool *reparse)
 {
 	int rc;
 	__u32 create_options = 0;
@@ -578,7 +578,7 @@ smb311_posix_query_path_info(const unsigned int xid, struct cifs_tcon *tcon,
 	struct smb311_posix_qinfo *smb2_data;
 
 	*adjust_tz = false;
-	*symlink = false;
+	*reparse = false;
 
 	/* BB TODO: Make struct larger when add support for parsing owner SIDs */
 	smb2_data = kzalloc(sizeof(struct smb311_posix_qinfo),
@@ -599,7 +599,7 @@ smb311_posix_query_path_info(const unsigned int xid, struct cifs_tcon *tcon,
 			      ACL_NO_MODE, smb2_data, SMB2_OP_POSIX_QUERY_INFO, cfile);
 	if (rc == -EOPNOTSUPP) {
 		/* BB TODO: When support for special files added to Samba re-verify this path */
-		*symlink = true;
+		*reparse = true;
 		create_options |= OPEN_REPARSE_POINT;
 
 		/* Failed on a symbolic link - query a reparse point info */
diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index 3cde719ec41b..0fe87f397ac5 100644
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -3034,6 +3034,138 @@ smb2_query_symlink(const unsigned int xid, struct cifs_tcon *tcon,
 	return rc;
 }
 
+int
+smb2_query_reparse_tag(const unsigned int xid, struct cifs_tcon *tcon,
+		   struct cifs_sb_info *cifs_sb, const char *full_path,
+		   __u32 *tag)
+{
+	int rc;
+	__le16 *utf16_path = NULL;
+	__u8 oplock = SMB2_OPLOCK_LEVEL_NONE;
+	struct cifs_open_parms oparms;
+	struct cifs_fid fid;
+	struct kvec err_iov = {NULL, 0};
+	struct TCP_Server_Info *server = cifs_pick_channel(tcon->ses);
+	int flags = 0;
+	struct smb_rqst rqst[3];
+	int resp_buftype[3];
+	struct kvec rsp_iov[3];
+	struct kvec open_iov[SMB2_CREATE_IOV_SIZE];
+	struct kvec io_iov[SMB2_IOCTL_IOV_SIZE];
+	struct kvec close_iov[1];
+	struct smb2_create_rsp *create_rsp;
+	struct smb2_ioctl_rsp *ioctl_rsp;
+	struct reparse_data_buffer *reparse_buf;
+	u32 plen;
+
+	cifs_dbg(FYI, "%s: path: %s\n", __func__, full_path);
+
+	if (smb3_encryption_required(tcon))
+		flags |= CIFS_TRANSFORM_REQ;
+
+	memset(rqst, 0, sizeof(rqst));
+	resp_buftype[0] = resp_buftype[1] = resp_buftype[2] = CIFS_NO_BUFFER;
+	memset(rsp_iov, 0, sizeof(rsp_iov));
+
+	utf16_path = cifs_convert_path_to_utf16(full_path, cifs_sb);
+	if (!utf16_path)
+		return -ENOMEM;
+
+	/*
+	 * setup smb2open - TODO add optimization to call cifs_get_readable_path
+	 * to see if there is a handle already open that we can use
+	 */
+	memset(&open_iov, 0, sizeof(open_iov));
+	rqst[0].rq_iov = open_iov;
+	rqst[0].rq_nvec = SMB2_CREATE_IOV_SIZE;
+
+	memset(&oparms, 0, sizeof(oparms));
+	oparms.tcon = tcon;
+	oparms.desired_access = FILE_READ_ATTRIBUTES;
+	oparms.disposition = FILE_OPEN;
+	oparms.create_options = cifs_create_options(cifs_sb, OPEN_REPARSE_POINT);
+	oparms.fid = &fid;
+	oparms.reconnect = false;
+
+	rc = SMB2_open_init(tcon, server,
+			    &rqst[0], &oplock, &oparms, utf16_path);
+	if (rc)
+		goto query_rp_exit;
+	smb2_set_next_command(tcon, &rqst[0]);
+
+
+	/* IOCTL */
+	memset(&io_iov, 0, sizeof(io_iov));
+	rqst[1].rq_iov = io_iov;
+	rqst[1].rq_nvec = SMB2_IOCTL_IOV_SIZE;
+
+	rc = SMB2_ioctl_init(tcon, server,
+			     &rqst[1], fid.persistent_fid,
+			     fid.volatile_fid, FSCTL_GET_REPARSE_POINT,
+			     true /* is_fctl */, NULL, 0,
+			     CIFSMaxBufSize -
+			     MAX_SMB2_CREATE_RESPONSE_SIZE -
+			     MAX_SMB2_CLOSE_RESPONSE_SIZE);
+	if (rc)
+		goto query_rp_exit;
+
+	smb2_set_next_command(tcon, &rqst[1]);
+	smb2_set_related(&rqst[1]);
+
+
+	/* Close */
+	memset(&close_iov, 0, sizeof(close_iov));
+	rqst[2].rq_iov = close_iov;
+	rqst[2].rq_nvec = 1;
+
+	rc = SMB2_close_init(tcon, server,
+			     &rqst[2], COMPOUND_FID, COMPOUND_FID, false);
+	if (rc)
+		goto query_rp_exit;
+
+	smb2_set_related(&rqst[2]);
+
+	rc = compound_send_recv(xid, tcon->ses, server,
+				flags, 3, rqst,
+				resp_buftype, rsp_iov);
+
+	create_rsp = rsp_iov[0].iov_base;
+	if (create_rsp && create_rsp->sync_hdr.Status)
+		err_iov = rsp_iov[0];
+	ioctl_rsp = rsp_iov[1].iov_base;
+
+	/*
+	 * Open was successful and we got an ioctl response.
+	 */
+	if (rc == 0) {
+		/* See MS-FSCC 2.3.23 */
+
+		reparse_buf = (struct reparse_data_buffer *)
+			((char *)ioctl_rsp +
+			 le32_to_cpu(ioctl_rsp->OutputOffset));
+		plen = le32_to_cpu(ioctl_rsp->OutputCount);
+
+		if (plen + le32_to_cpu(ioctl_rsp->OutputOffset) >
+		    rsp_iov[1].iov_len) {
+			cifs_tcon_dbg(FYI, "srv returned invalid ioctl len: %d\n",
+				 plen);
+			rc = -EIO;
+			goto query_rp_exit;
+		}
+		*tag = le32_to_cpu(reparse_buf->ReparseTag);
+	}
+
+ query_rp_exit:
+	kfree(utf16_path);
+	SMB2_open_free(&rqst[0]);
+	SMB2_ioctl_free(&rqst[1]);
+	SMB2_close_free(&rqst[2]);
+	free_rsp_buf(resp_buftype[0], rsp_iov[0].iov_base);
+	free_rsp_buf(resp_buftype[1], rsp_iov[1].iov_base);
+	free_rsp_buf(resp_buftype[2], rsp_iov[2].iov_base);
+	return rc;
+}
+
 static struct cifs_ntsd *
 get_smb2_acl_by_fid(struct cifs_sb_info *cifs_sb,
 		const struct cifs_fid *cifsfid, u32 *pacllen)
@@ -4986,6 +5118,8 @@ struct smb_version_operations smb30_operations = {
 	.can_echo = smb2_can_echo,
 	.echo = SMB2_echo,
 	.query_path_info = smb2_query_path_info,
+	/* WSL tags introduced long after smb2.1, enable for SMB3, 3.11 only */
+	.query_reparse_tag = smb2_query_reparse_tag,
 	.get_srv_inum = smb2_get_srv_inum,
 	.query_file_info = smb2_query_file_info,
 	.set_path_size = smb2_set_path_size,
@@ -5097,6 +5231,7 @@ struct smb_version_operations smb311_operations = {
 	.can_echo = smb2_can_echo,
 	.echo = SMB2_echo,
 	.query_path_info = smb2_query_path_info,
+	.query_reparse_tag = smb2_query_reparse_tag,
 	.get_srv_inum = smb2_get_srv_inum,
 	.query_file_info = smb2_query_file_info,
 	.set_path_size = smb2_set_path_size,
diff --git a/fs/cifs/smb2pdu.h b/fs/cifs/smb2pdu.h
index 171f54965703..14244d288b80 100644
--- a/fs/cifs/smb2pdu.h
+++ b/fs/cifs/smb2pdu.h
@@ -1691,6 +1691,11 @@ struct smb2_file_eof_info { /* encoding of request for level 10 */
 	__le64 EndOfFile; /* new end of file value */
 } __packed; /* level 20 Set */
 
+struct smb2_file_reparse_point_info {
+	__le64 IndexNumber;
+	__le32 Tag;
+} __packed;
+
 struct smb2_file_network_open_info {
 	__le64 CreationTime;
 	__le64 LastAccessTime;
diff --git a/fs/cifs/smb2proto.h b/fs/cifs/smb2proto.h
index 67c50d78caa1..d4110447ee3a 100644
--- a/fs/cifs/smb2proto.h
+++ b/fs/cifs/smb2proto.h
@@ -77,6 +77,9 @@ extern void close_shroot_lease(struct cached_fid *cfid);
 extern void close_shroot_lease_locked(struct cached_fid *cfid);
 extern void move_smb2_info_to_cifs(FILE_ALL_INFO *dst,
 				   struct smb2_file_all_info *src);
+extern int smb2_query_reparse_tag(const unsigned int xid, struct cifs_tcon *tcon,
+				struct cifs_sb_info *cifs_sb, const char *path,
+				__u32 *reparse_tag);
 extern int smb2_query_path_info(const unsigned int xid, struct cifs_tcon *tcon,
 				struct cifs_sb_info *cifs_sb,
 				const char *full_path, FILE_ALL_INFO *data,
-- 
2.25.1

