smb: client: use unaligned reads in parse_posix_ctxt()

commit b86467c upstream.

The server controls create-context DataOffset, so the POSIX context data
pointer may be misaligned on strict-alignment architectures. Use
get_unaligned_le32() when reading nlink, reparse_tag, and mode.

Fixes: 69dda30 ("cifs: add SMB2_open() arg to return POSIX data")
Cc: stable@vger.kernel.org
Signed-off-by: Zihan Xi <xizh2024@lzu.edu.cn>
Signed-off-by: Ren Wei <n05ec@lzu.edu.cn>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: Zihan Xi

fs/smb/client/smb2pdu.c

@@ -2307,9 +2307,9 @@ parse_posix_ctxt(struct create_context *cc, struct smb2_file_all_info *info,
 
 	memset(posix, 0, sizeof(*posix));
 
-	posix->nlink = le32_to_cpu(*(__le32 *)(beg + 0));
-	posix->reparse_tag = le32_to_cpu(*(__le32 *)(beg + 4));
-	posix->mode = le32_to_cpu(*(__le32 *)(beg + 8));
+	posix->nlink = get_unaligned_le32(beg);
+	posix->reparse_tag = get_unaligned_le32(beg + 4);
+	posix->mode = get_unaligned_le32(beg + 8);
 
 	sid = beg + 12;
 	sid_len = posix_info_sid_size(sid, end);