From 1713ce7c43755fe8b0f31ea317513129bf784909 Mon Sep 17 00:00:00 2001 From: Nathan Lynch Date: Wed, 25 Mar 2015 19:13:16 +0100 Subject: ARM: 8329/1: miscellaneous vdso infrastructure, preparation Define the layout of the data structure shared between kernel and userspace. Track the vdso address in the mm_context; needed for communicating AT_SYSINFO_EHDR to the ELF loader. Add declarations for arm_install_vdso; implementation is in a following patch. Define AT_SYSINFO_EHDR, and, if CONFIG_VDSO=y, report the vdso shared object address via the ELF auxiliary vector. Note - this adds the AT_SYSINFO_EHDR in a new user-visible header asm/auxvec.h; this is consistent with other architectures. Signed-off-by: Nathan Lynch Signed-off-by: Russell King --- arch/arm/include/asm/Kbuild | 1 - arch/arm/include/asm/auxvec.h | 1 + arch/arm/include/asm/elf.h | 9 ++++++ arch/arm/include/asm/mmu.h | 3 ++ arch/arm/include/asm/vdso.h | 32 +++++++++++++++++++ arch/arm/include/asm/vdso_datapage.h | 60 ++++++++++++++++++++++++++++++++++++ 6 files changed, 105 insertions(+), 1 deletion(-) create mode 100644 arch/arm/include/asm/auxvec.h create mode 100644 arch/arm/include/asm/vdso.h create mode 100644 arch/arm/include/asm/vdso_datapage.h (limited to 'arch/arm/include/asm') diff --git a/arch/arm/include/asm/Kbuild b/arch/arm/include/asm/Kbuild index fe74c0d1e485..eb0f43f3e3f1 100644 --- a/arch/arm/include/asm/Kbuild +++ b/arch/arm/include/asm/Kbuild @@ -1,6 +1,5 @@ -generic-y += auxvec.h generic-y += bitsperlong.h generic-y += cputime.h generic-y += current.h diff --git a/arch/arm/include/asm/auxvec.h b/arch/arm/include/asm/auxvec.h new file mode 100644 index 000000000000..fbd388c46299 --- /dev/null +++ b/arch/arm/include/asm/auxvec.h @@ -0,0 +1 @@ +#include diff --git a/arch/arm/include/asm/elf.h b/arch/arm/include/asm/elf.h index afb9cafd3786..ac3f17fb4c8d 100644 --- a/arch/arm/include/asm/elf.h +++ b/arch/arm/include/asm/elf.h @@ -1,7 +1,9 @@ #ifndef __ASMARM_ELF_H #define __ASMARM_ELF_H +#include #include +#include /* * ELF register definitions.. @@ -130,6 +132,13 @@ extern unsigned long arch_randomize_brk(struct mm_struct *mm); #define arch_randomize_brk arch_randomize_brk #ifdef CONFIG_MMU +#ifdef CONFIG_VDSO +#define ARCH_DLINFO \ +do { \ + NEW_AUX_ENT(AT_SYSINFO_EHDR, \ + (elf_addr_t)current->mm->context.vdso); \ +} while (0) +#endif #define ARCH_HAS_SETUP_ADDITIONAL_PAGES 1 struct linux_binprm; int arch_setup_additional_pages(struct linux_binprm *, int); diff --git a/arch/arm/include/asm/mmu.h b/arch/arm/include/asm/mmu.h index 64fd15159b7d..a5b47421059d 100644 --- a/arch/arm/include/asm/mmu.h +++ b/arch/arm/include/asm/mmu.h @@ -11,6 +11,9 @@ typedef struct { #endif unsigned int vmalloc_seq; unsigned long sigpage; +#ifdef CONFIG_VDSO + unsigned long vdso; +#endif } mm_context_t; #ifdef CONFIG_CPU_HAS_ASID diff --git a/arch/arm/include/asm/vdso.h b/arch/arm/include/asm/vdso.h new file mode 100644 index 000000000000..d0295f1dd1a3 --- /dev/null +++ b/arch/arm/include/asm/vdso.h @@ -0,0 +1,32 @@ +#ifndef __ASM_VDSO_H +#define __ASM_VDSO_H + +#ifdef __KERNEL__ + +#ifndef __ASSEMBLY__ + +struct mm_struct; + +#ifdef CONFIG_VDSO + +void arm_install_vdso(struct mm_struct *mm, unsigned long addr); + +extern char vdso_start, vdso_end; + +extern unsigned int vdso_total_pages; + +#else /* CONFIG_VDSO */ + +static inline void arm_install_vdso(struct mm_struct *mm, unsigned long addr) +{ +} + +#define vdso_total_pages 0 + +#endif /* CONFIG_VDSO */ + +#endif /* __ASSEMBLY__ */ + +#endif /* __KERNEL__ */ + +#endif /* __ASM_VDSO_H */ diff --git a/arch/arm/include/asm/vdso_datapage.h b/arch/arm/include/asm/vdso_datapage.h new file mode 100644 index 000000000000..9be259442fca --- /dev/null +++ b/arch/arm/include/asm/vdso_datapage.h @@ -0,0 +1,60 @@ +/* + * Adapted from arm64 version. + * + * Copyright (C) 2012 ARM Limited + * + * 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 + * published by the Free Software Foundation. + * + * This program 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 General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see . + */ +#ifndef __ASM_VDSO_DATAPAGE_H +#define __ASM_VDSO_DATAPAGE_H + +#ifdef __KERNEL__ + +#ifndef __ASSEMBLY__ + +#include + +/* Try to be cache-friendly on systems that don't implement the + * generic timer: fit the unconditionally updated fields in the first + * 32 bytes. + */ +struct vdso_data { + u32 seq_count; /* sequence count - odd during updates */ + u16 tk_is_cntvct; /* fall back to syscall if false */ + u16 cs_shift; /* clocksource shift */ + u32 xtime_coarse_sec; /* coarse time */ + u32 xtime_coarse_nsec; + + u32 wtm_clock_sec; /* wall to monotonic offset */ + u32 wtm_clock_nsec; + u32 xtime_clock_sec; /* CLOCK_REALTIME - seconds */ + u32 cs_mult; /* clocksource multiplier */ + + u64 cs_cycle_last; /* last cycle value */ + u64 cs_mask; /* clocksource mask */ + + u64 xtime_clock_snsec; /* CLOCK_REALTIME sub-ns base */ + u32 tz_minuteswest; /* timezone info for gettimeofday(2) */ + u32 tz_dsttime; +}; + +union vdso_data_store { + struct vdso_data data; + u8 page[PAGE_SIZE]; +}; + +#endif /* !__ASSEMBLY__ */ + +#endif /* __KERNEL__ */ + +#endif /* __ASM_VDSO_DATAPAGE_H */ -- cgit v1.2.2 From 8defb3367fcd19d1af64c07792aade0747b54e0f Mon Sep 17 00:00:00 2001 From: Andrey Ryabinin Date: Fri, 20 Mar 2015 15:42:27 +0100 Subject: ARM: 8320/1: fix integer overflow in ELF_ET_DYN_BASE Usually ELF_ET_DYN_BASE is 2/3 of TASK_SIZE. With 3G/1G user/kernel split this is not so, because 2*TASK_SIZE overflows 32 bits, so the actual value of ELF_ET_DYN_BASE is: (2 * TASK_SIZE / 3) = 0x2a000000 When ASLR is disabled PIE binaries will load at ELF_ET_DYN_BASE address. On 32bit platforms AddressSanitzer uses addresses [0x20000000 - 0x40000000] for shadow memory [1]. So ASan doesn't work for PIE binaries when ASLR disabled as it fails to map shadow memory. Also after Kees's 'split ET_DYN ASLR from mmap ASLR' patchset PIE binaries has a high chance of loading somewhere in between [0x2a000000 - 0x40000000] even if ASLR enabled. This makes ASan with PIE absolutely incompatible. Fix overflow by dividing TASK_SIZE prior to multiplying. After this patch ELF_ET_DYN_BASE equals to (for CONFIG_VMSPLIT_3G=y): (TASK_SIZE / 3 * 2) = 0x7f555554 [1] https://code.google.com/p/address-sanitizer/wiki/AddressSanitizerAlgorithm#Mapping Signed-off-by: Andrey Ryabinin Reported-by: Maria Guseva Cc: stable@vger.kernel.org Signed-off-by: Russell King --- arch/arm/include/asm/elf.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/arm/include/asm') diff --git a/arch/arm/include/asm/elf.h b/arch/arm/include/asm/elf.h index afb9cafd3786..674d03f4ba15 100644 --- a/arch/arm/include/asm/elf.h +++ b/arch/arm/include/asm/elf.h @@ -115,7 +115,7 @@ int dump_task_regs(struct task_struct *t, elf_gregset_t *elfregs); 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. */ -#define ELF_ET_DYN_BASE (2 * TASK_SIZE / 3) +#define ELF_ET_DYN_BASE (TASK_SIZE / 3 * 2) /* When the program starts, a1 contains a pointer to a function to be registered with atexit, as per the SVR4 ABI. A value of 0 means we -- cgit v1.2.2