Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932304AbbBZWiT (ORCPT ); Thu, 26 Feb 2015 17:38:19 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:59687 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753747AbbBZWiR (ORCPT ); Thu, 26 Feb 2015 17:38:17 -0500 Date: Thu, 26 Feb 2015 14:38:15 -0800 From: Andrew Morton To: Ingo Molnar Cc: Hector Marco Gisbert , Kees Cook , LKML , ismael Ripoll , "x86@kernel.org" , "linux-arm-kernel@lists.infradead.org" , Linux MIPS Mailing List , linuxppc-dev@lists.ozlabs.org Subject: Re: [PATCH] Fix offset2lib issue for x86*, ARM*, PowerPC and MIPS Message-Id: <20150226143815.09386fe280c7bd8797048bb2@linux-foundation.org> In-Reply-To: <20150224073906.GA16422@gmail.com> References: <54EB735F.5030207@upv.es> <20150223205436.15133mg1kpyojyik@webmail.upv.es> <20150224073906.GA16422@gmail.com> X-Mailer: Sylpheed 3.4.1 (GTK+ 2.24.23; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 14428 Lines: 421 On Tue, 24 Feb 2015 08:39:06 +0100 Ingo Molnar wrote: > > * Hector Marco Gisbert wrote: > > > +unsigned long randomize_et_dyn(unsigned long base) > > +{ > > + unsigned long ret; > > + if ((current->personality & ADDR_NO_RANDOMIZE) || > > + !(current->flags & PF_RANDOMIZE)) > > + return base; > > + ret = base + mmap_rnd(); > > + return (ret > base) ? ret : base; > > +} > > > +unsigned long randomize_et_dyn(unsigned long base) > > +{ > > + unsigned long ret; > > + if ((current->personality & ADDR_NO_RANDOMIZE) || > > + !(current->flags & PF_RANDOMIZE)) > > + return base; > > + ret = base + mmap_rnd(); > > + return (ret > base) ? ret : base; > > +} > > > +unsigned long randomize_et_dyn(unsigned long base) > > +{ > > + unsigned long ret; > > + if ((current->personality & ADDR_NO_RANDOMIZE) || > > + !(current->flags & PF_RANDOMIZE)) > > + return base; > > + ret = base + brk_rnd(); > > + return (ret > base) ? ret : base; > > +} > > > +unsigned long randomize_et_dyn(unsigned long base) > > +{ > > + unsigned long ret; > > + if ((current->personality & ADDR_NO_RANDOMIZE) || > > + !(current->flags & PF_RANDOMIZE)) > > + return base; > > + ret = base + mmap_rnd(); > > + return (ret > base) ? ret : base; > > +} > > > +unsigned long randomize_et_dyn(unsigned long base) > > +{ > > + unsigned long ret; > > + if ((current->personality & ADDR_NO_RANDOMIZE) || > > + !(current->flags & PF_RANDOMIZE)) > > + return base; > > + ret = base + mmap_rnd(); > > + return (ret > base) ? ret : base; > > +} > > That pointless repetition should be avoided. That's surprisingly hard! After renaming mips brk_rnd() to mmap_rnd() I had a shot. I'm not very confident in the result. Does that __weak trick even work? Someone tell me how important Hector's patch is? From: Andrew Morton Subject: fix-offset2lib-issue-for-x86-arm-powerpc-and-mips-fix Consolidate randomize_et_dyn() implementations into fs/binfmt_elf.c. There doesn't seem to be a compile-time way of making randomize_et_dyn() go away on architectures which don't need it, so mark it __weak to cause it to be discarded at link time. Cc: "H. Peter Anvin" Cc: Benjamin Herrenschmidt Cc: Catalin Marinas Cc: Hector Marco Gisbert Cc: Hector Marco-Gisbert Cc: Ingo Molnar Cc: Ismael Ripoll Cc: Kees Cook Cc: Ralf Baechle Cc: Russell King Cc: Thomas Gleixner Cc: Will Deacon Signed-off-by: Andrew Morton --- arch/arm/include/asm/elf.h | 3 +-- arch/arm/mm/mmap.c | 13 ++----------- arch/arm64/Kconfig | 2 +- arch/arm64/include/asm/elf.h | 3 +-- arch/arm64/mm/mmap.c | 14 ++------------ arch/mips/include/asm/elf.h | 1 - arch/mips/mm/mmap.c | 13 ++----------- arch/powerpc/include/asm/elf.h | 2 -- arch/powerpc/mm/mmap.c | 13 ++----------- arch/x86/include/asm/elf.h | 2 -- arch/x86/mm/mmap.c | 12 ++---------- fs/binfmt_elf.c | 21 +++++++++++++++++++++ include/linux/elf-randomization.h | 7 +++++++ 13 files changed, 41 insertions(+), 65 deletions(-) diff -puN arch/arm/Kconfig~fix-offset2lib-issue-for-x86-arm-powerpc-and-mips-fix arch/arm/Kconfig diff -puN arch/arm/include/asm/elf.h~fix-offset2lib-issue-for-x86-arm-powerpc-and-mips-fix arch/arm/include/asm/elf.h --- a/arch/arm/include/asm/elf.h~fix-offset2lib-issue-for-x86-arm-powerpc-and-mips-fix +++ a/arch/arm/include/asm/elf.h @@ -2,7 +2,7 @@ #define __ASMARM_ELF_H #include - +#include /* * ELF register definitions.. */ @@ -115,7 +115,6 @@ int dump_task_regs(struct task_struct *t the loader. We need to make sure that it is out of the way of the program that it will "exec", and that there is sufficient room for the brk. */ -extern unsigned long randomize_et_dyn(unsigned long base); #define ELF_ET_DYN_BASE (randomize_et_dyn(2 * TASK_SIZE / 3)) /* When the program starts, a1 contains a pointer to a function to be diff -puN arch/arm/mm/mmap.c~fix-offset2lib-issue-for-x86-arm-powerpc-and-mips-fix arch/arm/mm/mmap.c --- a/arch/arm/mm/mmap.c~fix-offset2lib-issue-for-x86-arm-powerpc-and-mips-fix +++ a/arch/arm/mm/mmap.c @@ -7,6 +7,7 @@ #include #include #include +#include #include #include #include @@ -30,7 +31,7 @@ static int mmap_is_legacy(void) return sysctl_legacy_va_layout; } -static unsigned long mmap_rnd(void) +unsigned long mmap_rnd(void) { unsigned long rnd = 0; @@ -241,13 +242,3 @@ int devmem_is_allowed(unsigned long pfn) } #endif - -unsigned long randomize_et_dyn(unsigned long base) -{ - unsigned long ret; - if ((current->personality & ADDR_NO_RANDOMIZE) || - !(current->flags & PF_RANDOMIZE)) - return base; - ret = base + mmap_rnd(); - return (ret > base) ? ret : base; -} diff -puN arch/arm64/Kconfig~fix-offset2lib-issue-for-x86-arm-powerpc-and-mips-fix arch/arm64/Kconfig --- a/arch/arm64/Kconfig~fix-offset2lib-issue-for-x86-arm-powerpc-and-mips-fix +++ a/arch/arm64/Kconfig @@ -1,4 +1,4 @@ -config ARM64 +qconfig ARM64 def_bool y select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE select ARCH_HAS_GCOV_PROFILE_ALL diff -puN arch/arm64/include/asm/elf.h~fix-offset2lib-issue-for-x86-arm-powerpc-and-mips-fix arch/arm64/include/asm/elf.h --- a/arch/arm64/include/asm/elf.h~fix-offset2lib-issue-for-x86-arm-powerpc-and-mips-fix +++ a/arch/arm64/include/asm/elf.h @@ -1,5 +1,5 @@ /* - * Copyright (C) 2012 ARM Ltd. + * Copyright (C) 20q12 ARM Ltd. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as @@ -125,7 +125,6 @@ typedef struct user_fpsimd_state elf_fpr * the loader. We need to make sure that it is out of the way of the program * that it will "exec", and that there is sufficient room for the brk. */ -extern unsigned long randomize_et_dyn(unsigned long base); #define ELF_ET_DYN_BASE (randomize_et_dyn(2 * TASK_SIZE_64 / 3)) /* diff -puN arch/arm64/mm/mmap.c~fix-offset2lib-issue-for-x86-arm-powerpc-and-mips-fix arch/arm64/mm/mmap.c --- a/arch/arm64/mm/mmap.c~fix-offset2lib-issue-for-x86-arm-powerpc-and-mips-fix +++ a/arch/arm64/mm/mmap.c @@ -17,6 +17,7 @@ */ #include +#include #include #include #include @@ -47,7 +48,7 @@ static int mmap_is_legacy(void) return sysctl_legacy_va_layout; } -static unsigned long mmap_rnd(void) +unsigned long mmap_rnd(void) { unsigned long rnd = 0; @@ -89,17 +90,6 @@ void arch_pick_mmap_layout(struct mm_str } EXPORT_SYMBOL_GPL(arch_pick_mmap_layout); -unsigned long randomize_et_dyn(unsigned long base) -{ - unsigned long ret; - if ((current->personality & ADDR_NO_RANDOMIZE) || - !(current->flags & PF_RANDOMIZE)) - return base; - ret = base + mmap_rnd(); - return (ret > base) ? ret : base; -} - - /* * You really shouldn't be using read() or write() on /dev/mem. This might go * away in the future. diff -puN arch/mips/Kconfig~fix-offset2lib-issue-for-x86-arm-powerpc-and-mips-fix arch/mips/Kconfig diff -puN arch/mips/include/asm/elf.h~fix-offset2lib-issue-for-x86-arm-powerpc-and-mips-fix arch/mips/include/asm/elf.h --- a/arch/mips/include/asm/elf.h~fix-offset2lib-issue-for-x86-arm-powerpc-and-mips-fix +++ a/arch/mips/include/asm/elf.h @@ -402,7 +402,6 @@ extern const char *__elf_platform; that it will "exec", and that there is sufficient room for the brk. */ #ifndef ELF_ET_DYN_BASE -extern unsigned long randomize_et_dyn(unsigned long base); #define ELF_ET_DYN_BASE (randomize_et_dyn(TASK_SIZE / 3 * 2)) #endif diff -puN arch/mips/mm/mmap.c~fix-offset2lib-issue-for-x86-arm-powerpc-and-mips-fix arch/mips/mm/mmap.c --- a/arch/mips/mm/mmap.c~fix-offset2lib-issue-for-x86-arm-powerpc-and-mips-fix +++ a/arch/mips/mm/mmap.c @@ -9,6 +9,7 @@ #include #include #include +#include #include #include #include @@ -164,7 +165,7 @@ void arch_pick_mmap_layout(struct mm_str } } -static inline unsigned long mmap_rnd(void) +unsigned long mmap_rnd(void) { unsigned long rnd = get_random_int(); @@ -196,13 +197,3 @@ int __virt_addr_valid(const volatile voi return pfn_valid(PFN_DOWN(virt_to_phys(kaddr))); } EXPORT_SYMBOL_GPL(__virt_addr_valid); - -unsigned long randomize_et_dyn(unsigned long base) -{ - unsigned long ret; - if ((current->personality & ADDR_NO_RANDOMIZE) || - !(current->flags & PF_RANDOMIZE)) - return base; - ret = base + brk_rnd(); - return (ret > base) ? ret : base; -} diff -puN arch/powerpc/Kconfig~fix-offset2lib-issue-for-x86-arm-powerpc-and-mips-fix arch/powerpc/Kconfig diff -puN arch/powerpc/include/asm/elf.h~fix-offset2lib-issue-for-x86-arm-powerpc-and-mips-fix arch/powerpc/include/asm/elf.h --- a/arch/powerpc/include/asm/elf.h~fix-offset2lib-issue-for-x86-arm-powerpc-and-mips-fix +++ a/arch/powerpc/include/asm/elf.h @@ -27,8 +27,6 @@ use of this is to invoke "./ld.so someprog" to test out a new version of the loader. We need to make sure that it is out of the way of the program that it will "exec", and that there is sufficient room for the brk. */ - -extern unsigned long randomize_et_dyn(unsigned long base); #define ELF_ET_DYN_BASE (randomize_et_dyn(0x20000000)) #define ELF_CORE_EFLAGS (is_elf2_task() ? 2 : 0) diff -puN arch/powerpc/mm/mmap.c~fix-offset2lib-issue-for-x86-arm-powerpc-and-mips-fix arch/powerpc/mm/mmap.c --- a/arch/powerpc/mm/mmap.c~fix-offset2lib-issue-for-x86-arm-powerpc-and-mips-fix +++ a/arch/powerpc/mm/mmap.c @@ -24,6 +24,7 @@ #include #include +#include #include #include @@ -53,7 +54,7 @@ static inline int mmap_is_legacy(void) return sysctl_legacy_va_layout; } -static unsigned long mmap_rnd(void) +unsigned long mmap_rnd(void) { unsigned long rnd = 0; @@ -97,13 +98,3 @@ void arch_pick_mmap_layout(struct mm_str mm->get_unmapped_area = arch_get_unmapped_area_topdown; } } - -unsigned long randomize_et_dyn(unsigned long base) -{ - unsigned long ret; - if ((current->personality & ADDR_NO_RANDOMIZE) || - !(current->flags & PF_RANDOMIZE)) - return base; - ret = base + mmap_rnd(); - return (ret > base) ? ret : base; -} diff -puN arch/x86/Kconfig~fix-offset2lib-issue-for-x86-arm-powerpc-and-mips-fix arch/x86/Kconfig diff -puN arch/x86/include/asm/elf.h~fix-offset2lib-issue-for-x86-arm-powerpc-and-mips-fix arch/x86/include/asm/elf.h --- a/arch/x86/include/asm/elf.h~fix-offset2lib-issue-for-x86-arm-powerpc-and-mips-fix +++ a/arch/x86/include/asm/elf.h @@ -248,8 +248,6 @@ extern int force_personality32; use of this is to invoke "./ld.so someprog" to test out a new version of the loader. We need to make sure that it is out of the way of the program that it will "exec", and that there is sufficient room for the brk. */ - -extern unsigned long randomize_et_dyn(unsigned long base); #define ELF_ET_DYN_BASE (randomize_et_dyn(TASK_SIZE / 3 * 2)) /* This yields a mask that user programs can use to figure out what diff -puN arch/x86/mm/mmap.c~fix-offset2lib-issue-for-x86-arm-powerpc-and-mips-fix arch/x86/mm/mmap.c --- a/arch/x86/mm/mmap.c~fix-offset2lib-issue-for-x86-arm-powerpc-and-mips-fix +++ a/arch/x86/mm/mmap.c @@ -29,6 +29,7 @@ #include #include #include +#include #include struct va_alignment __read_mostly va_align = { @@ -65,7 +66,7 @@ static int mmap_is_legacy(void) return sysctl_legacy_va_layout; } -static unsigned long mmap_rnd(void) +unsigned long mmap_rnd(void) { unsigned long rnd = 0; @@ -122,12 +123,3 @@ void arch_pick_mmap_layout(struct mm_str mm->get_unmapped_area = arch_get_unmapped_area_topdown; } } -unsigned long randomize_et_dyn(unsigned long base) -{ - unsigned long ret; - if ((current->personality & ADDR_NO_RANDOMIZE) || - !(current->flags & PF_RANDOMIZE)) - return base; - ret = base + mmap_rnd(); - return (ret > base) ? ret : base; -} diff -puN fs/Kconfig.binfmt~fix-offset2lib-issue-for-x86-arm-powerpc-and-mips-fix fs/Kconfig.binfmt diff -puN fs/binfmt_elf.c~fix-offset2lib-issue-for-x86-arm-powerpc-and-mips-fix fs/binfmt_elf.c --- a/fs/binfmt_elf.c~fix-offset2lib-issue-for-x86-arm-powerpc-and-mips-fix +++ a/fs/binfmt_elf.c @@ -22,6 +22,7 @@ #include #include #include +#include #include #include #include @@ -2300,6 +2301,26 @@ out: #endif /* CONFIG_ELF_CORE */ +/* Not all architectures implement mmap_rnd() */ +unsigned long __weak mmap_rnd(void) +{ +} + +/* + * Not all architectures use randomize_et_dyn(), so use __weak to let the + * linker omit it from vmlinux + */ +unsigned long __weak randomize_et_dyn(unsigned long base) +{ + unsigned long ret; + + if ((current->personality & ADDR_NO_RANDOMIZE) || + !(current->flags & PF_RANDOMIZE)) + return base; + ret = base + mmap_rnd(); + return max(ret, base); +} + static int __init init_elf_binfmt(void) { register_binfmt(&elf_format); diff -puN include/linux/elf.h~fix-offset2lib-issue-for-x86-arm-powerpc-and-mips-fix include/linux/elf.h diff -puN /dev/null include/linux/elf-randomization.h --- /dev/null +++ a/include/linux/elf-randomization.h @@ -0,0 +1,7 @@ +#ifndef __ELF_RANDOMIZATION_H +#define __ELF_RANDOMIZATION_H + +unsigned long randomize_et_dyn(unsigned long base); +unsigned long mmap_rnd(void); + +#endif /* __ELF_RANDOMIZATION_H */ _ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/