smb: client: parse uid, gid, mode and dev from WSL reparse points

Parse the extended attributes from WSL reparse points to correctly
report uid, gid mode and dev from ther instantiated inodes.

Signed-off-by: Paulo Alcantara <[e-mail]>
Signed-off-by: Steve French <[e-mail]>

fs/smb/client/inode.c

···
 	fattr->cf_bytes = le64_to_cpu(info->AllocationSize);
 	fattr->cf_createtime = le64_to_cpu(info->CreationTime);
 	fattr->cf_nlink = le32_to_cpu(info->NumberOfLinks);
+	fattr->cf_uid = cifs_sb->ctx->linux_uid;
+	fattr->cf_gid = cifs_sb->ctx->linux_gid;
 
 	fattr->cf_mode = cifs_sb->ctx->file_mode;
 	if (cifs_open_data_reparse(data) &&
···
 		fattr->cf_symlink_target = data->symlink_target;
 		data->symlink_target = NULL;
 	}
-
-	fattr->cf_uid = cifs_sb->ctx->linux_uid;
-	fattr->cf_gid = cifs_sb->ctx->linux_gid;
 }
 
 static int

fs/smb/client/readdir.c

···
 					if (likely(reparse_inode_match(inode, fattr))) {
 						fattr->cf_mode = inode->i_mode;
 						fattr->cf_rdev = inode->i_rdev;
+						fattr->cf_uid = inode->i_uid;
+						fattr->cf_gid = inode->i_gid;
 						fattr->cf_eof = CIFS_I(inode)->netfs.remote_i_size;
 						fattr->cf_symlink_target = NULL;
 					} else {

fs/smb/client/reparse.c

···
 {
 	struct cifs_open_info_data data;
 	struct reparse_data_buffer buf;
+	struct smb2_create_ea_ctx *cc;
 	struct inode *new;
+	unsigned int len;
 	struct kvec reparse_iov, xattr_iov;
 	int rc;
 
···
 		.reparse_point = true,
 		.reparse = { .tag = le32_to_cpu(buf.ReparseTag), .buf = &buf, },
 	};
+
+	cc = xattr_iov.iov_base;
+	len = le32_to_cpu(cc->ctx.DataLength);
+	memcpy(data.wsl.eas, &cc->ea, len);
+	data.wsl.eas_len = len;
 
 	new = smb2_get_reparse_inode(&data, inode->i_sb,
 				     xid, tcon, full_path,
···
 	return parse_reparse_point(buf, plen, cifs_sb, true, data);
 }
 
+static void wsl_to_fattr(struct cifs_open_info_data *data,
+			 struct cifs_sb_info *cifs_sb,
+			 u32 tag, struct cifs_fattr *fattr)
+{
+	struct smb2_file_full_ea_info *ea;
+	u32 next = 0;
+
+	switch (tag) {
+	case IO_REPARSE_TAG_LX_SYMLINK:
+		fattr->cf_mode |= S_IFLNK;
+		break;
+	case IO_REPARSE_TAG_LX_FIFO:
+		fattr->cf_mode |= S_IFIFO;
+		break;
+	case IO_REPARSE_TAG_AF_UNIX:
+		fattr->cf_mode |= S_IFSOCK;
+		break;
+	case IO_REPARSE_TAG_LX_CHR:
+		fattr->cf_mode |= S_IFCHR;
+		break;
+	case IO_REPARSE_TAG_LX_BLK:
+		fattr->cf_mode |= S_IFBLK;
+		break;
+	}
+
+	if (!data->wsl.eas_len)
+		goto out;
+
+	ea = (struct smb2_file_full_ea_info *)data->wsl.eas;
+	do {
+		const char *name;
+		void *v;
+		u8 nlen;
+
+		ea = (void *)((u8 *)ea + next);
+		next = le32_to_cpu(ea->next_entry_offset);
+		if (!le16_to_cpu(ea->ea_value_length))
+			continue;
+
+		name = ea->ea_data;
+		nlen = ea->ea_name_length;
+		v = (void *)((u8 *)ea->ea_data + ea->ea_name_length + 1);
+
+		if (!strncmp(name, SMB2_WSL_XATTR_UID, nlen))
+			fattr->cf_uid = wsl_make_kuid(cifs_sb, v);
+		else if (!strncmp(name, SMB2_WSL_XATTR_GID, nlen))
+			fattr->cf_gid = wsl_make_kgid(cifs_sb, v);
+		else if (!strncmp(name, SMB2_WSL_XATTR_MODE, nlen))
+			fattr->cf_mode = (umode_t)le32_to_cpu(*(__le32 *)v);
+		else if (!strncmp(name, SMB2_WSL_XATTR_DEV, nlen))
+			fattr->cf_rdev = wsl_mkdev(v);
+	} while (next);
+out:
+	fattr->cf_dtype = S_DT(fattr->cf_mode);
+}
+
 bool cifs_reparse_point_to_fattr(struct cifs_sb_info *cifs_sb,
 				 struct cifs_fattr *fattr,
 				 struct cifs_open_info_data *data)
···
 
 	switch (tag) {
 	case IO_REPARSE_TAG_LX_SYMLINK:
-		fattr->cf_mode |= S_IFLNK;
-		fattr->cf_dtype = DT_LNK;
-		break;
 	case IO_REPARSE_TAG_LX_FIFO:
-		fattr->cf_mode |= S_IFIFO;
-		fattr->cf_dtype = DT_FIFO;
-		break;
 	case IO_REPARSE_TAG_AF_UNIX:
-		fattr->cf_mode |= S_IFSOCK;
-		fattr->cf_dtype = DT_SOCK;
-		break;
 	case IO_REPARSE_TAG_LX_CHR:
-		fattr->cf_mode |= S_IFCHR;
-		fattr->cf_dtype = DT_CHR;
-		break;
 	case IO_REPARSE_TAG_LX_BLK:
-		fattr->cf_mode |= S_IFBLK;
-		fattr->cf_dtype = DT_BLK;
+		wsl_to_fattr(data, cifs_sb, tag, fattr);
 		break;
 	case 0: /* SMB1 symlink */
 	case IO_REPARSE_TAG_SYMLINK:

fs/smb/client/reparse.h

···
 
 #include <linux/fs.h>
 #include <linux/stat.h>
+#include <linux/uidgid.h>
+#include "fs_context.h"
 #include "cifsglob.h"
 
 static inline dev_t reparse_nfs_mkdev(struct reparse_posix_data *buf)
···
 	u64 v = le64_to_cpu(*(__le64 *)buf->DataBuffer);
 
 	return MKDEV(v >> 32, v & 0xffffffff);
+}
+
+static inline dev_t wsl_mkdev(void *ptr)
+{
+	u64 v = le64_to_cpu(*(__le64 *)ptr);
+
+	return MKDEV(v & 0xffffffff, v >> 32);
+}
+
+static inline kuid_t wsl_make_kuid(struct cifs_sb_info *cifs_sb,
+				   void *ptr)
+{
+	u32 uid = le32_to_cpu(*(__le32 *)ptr);
+
+	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_OVERR_UID)
+		return cifs_sb->ctx->linux_uid;
+	return make_kuid(current_user_ns(), uid);
+}
+
+static inline kgid_t wsl_make_kgid(struct cifs_sb_info *cifs_sb,
+				   void *ptr)
+{
+	u32 gid = le32_to_cpu(*(__le32 *)ptr);
+
+	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_OVERR_GID)
+		return cifs_sb->ctx->linux_gid;
+	return make_kgid(current_user_ns(), gid);
 }
 
 static inline u64 reparse_mode_nfs_type(mode_t mode)