From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030301AbWBTQOF (ORCPT ); Mon, 20 Feb 2006 11:14:05 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1030302AbWBTQOF (ORCPT ); Mon, 20 Feb 2006 11:14:05 -0500 Received: from moutng.kundenserver.de ([212.227.126.186]:743 "EHLO moutng.kundenserver.de") by vger.kernel.org with ESMTP id S1030301AbWBTQOD (ORCPT ); Mon, 20 Feb 2006 11:14:03 -0500 From: Arnd Bergmann To: Mishin Dmitry Subject: Re: [PATCH 1/2] iptables 32bit compat layer Date: Mon, 20 Feb 2006 16:55:26 +0100 User-Agent: KMail/1.9.1 Cc: "David S. Miller" , linux-kernel@vger.kernel.org, netfilter-devel@lists.netfilter.org, rusty@rustcorp.com.au, akpm@osdl.org, devel@openvz.org References: <200602201110.39092.dim@openvz.org> In-Reply-To: <200602201110.39092.dim@openvz.org> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 8bit Content-Disposition: inline Message-Id: <200602201655.27093.arnd@arndb.de> X-Provags-ID: kundenserver.de abuse@kundenserver.de login:c48f057754fc1b1a557605ab9fa6da41 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Monday 20 February 2006 09:10, Mishin Dmitry wrote: > --- ./include/linux/netfilter/x_tables.h.iptcompat      2006-02-15 16:16:02.000000000 +0300 > +++ ./include/linux/netfilter/x_tables.h        2006-02-15 18:53:09.000000000 +0300 >  struct xt_match >  { >         struct list_head list; > @@ -118,6 +125,10 @@ struct xt_match >         /* Called when entry of this type deleted. */ >         void (*destroy)(void *matchinfo, unsigned int matchinfosize); >   > +#ifdef CONFIG_COMPAT > +       /* Called when userspace align differs from kernel space one */ > +       int (*compat)(void *match, void **dstptr, int *size, int convert); > +#endif >         /* Set this to THIS_MODULE if you are a module, otherwise NULL */ >         struct module *me; >  }; Is CONFIG_COMPAT the right conditional here? If the code is only used for architectures that have different aligments, it should not need be compiled in for the other architectures. > @@ -154,6 +165,10 @@ struct xt_target >         /* Called when entry of this type deleted. */ >         void (*destroy)(void *targinfo, unsigned int targinfosize); >   > +#ifdef CONFIG_COMPAT > +       /* Called when userspace align differs from kernel space one */ > +       int (*compat)(void *target, void **dstptr, int *size, int convert); > +#endif >         /* Set this to THIS_MODULE if you are a module, otherwise NULL */ >         struct module *me; >  }; > @@ -233,6 +248,34 @@ extern void xt_proto_fini(int af); >  extern struct xt_table_info *xt_alloc_table_info(unsigned int size); >  extern void xt_free_table_info(struct xt_table_info *info); >   > +#ifdef CONFIG_COMPAT > +#include > + > +/* FIXME: this works only on 32 bit tasks > + * need to change whole approach in order to calculate align as function of > + * current task alignment */ > + > +struct compat_xt_counters > +{ > +       u_int32_t cnt[4]; > +}; Hmm, maybe we should have something like typedef u64 __attribute__((aligned(4))) compat_u64; in order to get the right alignment on the architectures where it makes a difference. Do all compiler versions get that right? > --- ./include/linux/netfilter_ipv4/ip_tables.h.iptcompat        2006-02-15 16:06:41.000000000 +0300 > +++ ./include/linux/netfilter_ipv4/ip_tables.h  2006-02-15 16:37:12.000000000 +0300 > @@ -364,5 +365,62 @@ extern unsigned int ipt_do_table(struct >                                  void *userdata); >   >  #define IPT_ALIGN(s) XT_ALIGN(s) > + > +#ifdef CONFIG_COMPAT > +#include > + > +struct compat_ipt_getinfo > +{ > +       char name[IPT_TABLE_MAXNAMELEN]; > +       compat_uint_t valid_hooks; > +       compat_uint_t hook_entry[NF_IP_NUMHOOKS]; > +       compat_uint_t underflow[NF_IP_NUMHOOKS]; > +       compat_uint_t num_entries; > +       compat_uint_t size; > +}; This structure looks like it does not need any conversions. You should probably just use struct ipt_getinfo then. > + > +struct compat_ipt_entry_match > +{ > +       union { > +               struct { > +                       u_int16_t match_size; > +                       char name[IPT_FUNCTION_MAXNAMELEN]; > +               } user; > +               u_int16_t match_size; > +       } u; > +       unsigned char data[0]; > +}; > + > +struct compat_ipt_entry_target > +{ > +       union { > +               struct { > +                       u_int16_t target_size; > +                       char name[IPT_FUNCTION_MAXNAMELEN]; > +               } user; > +               u_int16_t target_size; > +       } u; > +       unsigned char data[0]; > +}; Dito > +#define COMPAT_IPT_ALIGN(s)    COMPAT_XT_ALIGN(s) > + > +extern int ipt_match_align_compat(void *match, void **dstptr, > +               int *size, int off, int convert); > +extern int ipt_target_align_compat(void *target, void **dstptr, > +               int *size, int off, int convert); > + > +#endif /* CONFIG_COMPAT */ >  #endif /*__KERNEL__*/ >  #endif /* _IPTABLES_H */ > --- ./include/net/compat.h.iptcompat    2006-01-03 06:21:10.000000000 +0300 > +++ ./include/net/compat.h      2006-02-15 18:45:49.000000000 +0300 > @@ -23,6 +23,14 @@ struct compat_cmsghdr { >         compat_int_t    cmsg_type; >  }; >   > +#if defined(CONFIG_X86_64) > +#define is_current_32bits() (current_thread_info()->flags & _TIF_IA32) > +#elif defined(CONFIG_IA64) > +#define is_current_32bits() (IS_IA32_PROCESS(ia64_task_regs(current))) > +#else > +#define is_current_32bits()    0 > +#endif > + This definition looks very wrong to me. For x86_64, the right thing to check should be TS_COMPAT, no _TIF_IA32, since you can also call the 64 bit syscall entry point from a i386 task running on x86_64. For most other architectures, is_current_32bits returns something that is not reflected in the name. I would e.g. expect the function to return '1' on i386 and the correct task state on other compat platforms, instead of a bogus '0'. There have been long discussions about the inclusions of the 'is_compat_task' macro. Let's at least not define a second function that does almost the same but gets it wrong. I would much rather have either an extra 'compat' argument to to sock_setsockopt and proto_ops->setsockopt than to spread the use of is_compat_task further. >  #else /* defined(CONFIG_COMPAT) */ >  #define compat_msghdr  msghdr          /* to avoid compiler warnings */ >  #endif /* defined(CONFIG_COMPAT) */ > --- ./net/compat.c.iptcompat    2006-01-03 06:21:10.000000000 +0300 > +++ ./net/compat.c      2006-02-15 16:38:45.000000000 +0300 > @@ -308,107 +308,6 @@ void scm_detach_fds_compat(struct msghdr >  } >   >  /* > - * For now, we assume that the compatibility and native version > - * of struct ipt_entry are the same - sfr.  FIXME > - */ > -struct compat_ipt_replace { > -       char                    name[IPT_TABLE_MAXNAMELEN]; > -       u32                     valid_hooks; > -       u32                     num_entries; > -       u32                     size; > -       u32                     hook_entry[NF_IP_NUMHOOKS]; > -       u32                     underflow[NF_IP_NUMHOOKS]; > -       u32                     num_counters; > -       compat_uptr_t           counters;       /* struct ipt_counters * */ > -       struct ipt_entry        entries[0]; > -}; Is the FIXME above the only reason that the code needs to be changed? What is the reason that you did not just address this in the compat_sys_setsockopt implementation? Arnd <><