From 3375cfafa7961c6ae0e509c31c3b3cef9ad1f03d Mon Sep 17 00:00:00 2001 From: Florian Weimer Date: Mon, 23 May 2016 19:43:09 +0200 Subject: Make padding in struct sockaddr_storage explicit [BZ #20111] This avoids aliasing issues with GCC 6 in -fno-strict-aliasing mode. (With implicit padding, not all data is copied.) This change makes it explicit that struct sockaddr_storage is only 126 bytes large on m68k (unlike elsewhere, where we end up with the requested 128 bytes). The new test case makes sure that this does not happen on other architectures. --- sysdeps/unix/sysv/linux/bits/socket.h | 8 +++--- sysdeps/unix/sysv/linux/m68k/bits/sockaddr.h | 42 ++++++++++++++++++++++++++++ 2 files changed, 46 insertions(+), 4 deletions(-) create mode 100644 sysdeps/unix/sysv/linux/m68k/bits/sockaddr.h (limited to 'sysdeps/unix/sysv/linux') diff --git a/sysdeps/unix/sysv/linux/bits/socket.h b/sysdeps/unix/sysv/linux/bits/socket.h index a57048c04d..2eb95f7e20 100644 --- a/sysdeps/unix/sysv/linux/bits/socket.h +++ b/sysdeps/unix/sysv/linux/bits/socket.h @@ -175,16 +175,16 @@ struct sockaddr /* Structure large enough to hold any socket address (with the historical - exception of AF_UNIX). We reserve 128 bytes. */ + exception of AF_UNIX). */ #define __ss_aligntype unsigned long int -#define _SS_SIZE 128 -#define _SS_PADSIZE (_SS_SIZE - (2 * sizeof (__ss_aligntype))) +#define _SS_PADSIZE \ + (_SS_SIZE - __SOCKADDR_COMMON_SIZE - sizeof (__ss_aligntype)) struct sockaddr_storage { __SOCKADDR_COMMON (ss_); /* Address family, etc. */ - __ss_aligntype __ss_align; /* Force desired alignment. */ char __ss_padding[_SS_PADSIZE]; + __ss_aligntype __ss_align; /* Force desired alignment. */ }; diff --git a/sysdeps/unix/sysv/linux/m68k/bits/sockaddr.h b/sysdeps/unix/sysv/linux/m68k/bits/sockaddr.h new file mode 100644 index 0000000000..5721f99fd9 --- /dev/null +++ b/sysdeps/unix/sysv/linux/m68k/bits/sockaddr.h @@ -0,0 +1,42 @@ +/* Definition of struct sockaddr_* members and sizes, Linux/m68k version. + Copyright (C) 1995-2016 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + . */ + +/* + * Never include this file directly; use instead. + */ + +#ifndef _BITS_SOCKADDR_H +#define _BITS_SOCKADDR_H 1 + + +/* POSIX.1g specifies this type name for the `sa_family' member. */ +typedef unsigned short int sa_family_t; + +/* This macro is used to declare the initial common members + of the data types used for socket addresses, `struct sockaddr', + `struct sockaddr_in', `struct sockaddr_un', etc. */ + +#define __SOCKADDR_COMMON(sa_prefix) \ + sa_family_t sa_prefix##family + +#define __SOCKADDR_COMMON_SIZE (sizeof (unsigned short int)) + +/* Size of struct sockaddr_storage. */ +#define _SS_SIZE 126 + +#endif /* bits/sockaddr.h */ -- cgit 1.4.1