Commit d5ecebc4 authored by Steve French's avatar Steve French
Browse files

smb3: Allow query of symlinks stored as reparse points 



The 'NFS' style symlinks (see MS-FSCC 2.1.2.4) were not
being queried properly in query_symlink. Fix this.

Signed-off-by: default avatarSteve French <stfrench@microsoft.com>
Reviewed-by: default avatarRonnie Sahlberg <lsahlber@redhat.com>
parent f2caf901

fs/cifs/smb2ops.c

+54 −6
Original line number Diff line number Diff line
@@ -2373,6 +2373,39 @@ smb2_get_dfs_refer(const unsigned int xid, struct cifs_ses *ses, 
	return rc;

}



static int

parse_reparse_posix(struct reparse_posix_data *symlink_buf,

		      u32 plen, char **target_path,

		      struct cifs_sb_info *cifs_sb)

{

	unsigned int len;



	/* See MS-FSCC 2.1.2.6 for the 'NFS' style reparse tags */

	len = le16_to_cpu(symlink_buf->ReparseDataLength);



	if (len + sizeof(struct reparse_data_buffer) > plen) {

		cifs_dbg(VFS, "srv returned malformed symlink buffer\n");

		return -EINVAL;

	}



	if (le64_to_cpu(symlink_buf->InodeType) != NFS_SPECFILE_LNK) {

		cifs_dbg(VFS, "%lld not a supported symlink type\n",

			le64_to_cpu(symlink_buf->InodeType));

		return -EOPNOTSUPP;

	}



	*target_path = cifs_strndup_from_utf16(

				symlink_buf->PathBuffer,

				len, true, cifs_sb->local_nls);

	if (!(*target_path))

		return -ENOMEM;



	convert_delimiter(*target_path, '/');

	cifs_dbg(FYI, "%s: target path: %s\n", __func__, *target_path);



	return 0;

}



static int

parse_reparse_symlink(struct reparse_symlink_data_buffer *symlink_buf,

		      u32 plen, char **target_path,
@@ -2381,11 +2414,7 @@ parse_reparse_symlink(struct reparse_symlink_data_buffer *symlink_buf, 
	unsigned int sub_len;

	unsigned int sub_offset;



	/* We only handle Symbolic Link : MS-FSCC 2.1.2.4 */

	if (le32_to_cpu(symlink_buf->ReparseTag) != IO_REPARSE_TAG_SYMLINK) {

		cifs_dbg(VFS, "srv returned invalid symlink buffer\n");

		return -EIO;

	}

	/* We handle Symbolic Link reparse tag here. See: MS-FSCC 2.1.2.4 */



	sub_offset = le16_to_cpu(symlink_buf->SubstituteNameOffset);

	sub_len = le16_to_cpu(symlink_buf->SubstituteNameLength);
@@ -2407,6 +2436,25 @@ parse_reparse_symlink(struct reparse_symlink_data_buffer *symlink_buf, 
	return 0;

}



static int

parse_reparse_point(struct reparse_symlink_data_buffer *buf,

		      u32 plen, char **target_path,

		      struct cifs_sb_info *cifs_sb)

{

	/* See MS-FSCC 2.1.2 */

	if (le32_to_cpu(buf->ReparseTag) == IO_REPARSE_TAG_NFS)

		return parse_reparse_posix((struct reparse_posix_data *)buf,

			plen, target_path, cifs_sb);

	else if (le32_to_cpu(buf->ReparseTag) == IO_REPARSE_TAG_SYMLINK)

		return parse_reparse_symlink(buf, plen, target_path,

					cifs_sb);



	cifs_dbg(VFS, "srv returned invalid symlink buffer tag:%d\n",

		le32_to_cpu(buf->ReparseTag));



	return -EIO;

}



#define SMB2_SYMLINK_STRUCT_SIZE \

	(sizeof(struct smb2_err_rsp) - 1 + sizeof(struct smb2_symlink_err_rsp))
@@ -2547,7 +2595,7 @@ smb2_query_symlink(const unsigned int xid, struct cifs_tcon *tcon, 
			goto querty_exit;

		}



		rc = parse_reparse_symlink(

		rc = parse_reparse_point(

			(struct reparse_symlink_data_buffer *)reparse_buf,

			plen, target_path, cifs_sb);

		goto querty_exit;