diff options
Diffstat (limited to 'arch/arm')
| -rw-r--r-- | arch/arm/include/asm/elf.h | 4 | ||||
| -rw-r--r-- | arch/arm/include/asm/mmu.h | 1 | ||||
| -rw-r--r-- | arch/arm/kernel/process.c | 40 | ||||
| -rw-r--r-- | arch/arm/kernel/signal.c | 52 | ||||
| -rw-r--r-- | arch/arm/kernel/signal.h | 12 | ||||
| -rw-r--r-- | arch/arm/kernel/traps.c | 9 |
6 files changed, 87 insertions, 31 deletions
diff --git a/arch/arm/include/asm/elf.h b/arch/arm/include/asm/elf.h index 38050b1..9c9b307 100644 --- a/arch/arm/include/asm/elf.h +++ b/arch/arm/include/asm/elf.h @@ -130,4 +130,8 @@ struct mm_struct; extern unsigned long arch_randomize_brk(struct mm_struct *mm); #define arch_randomize_brk arch_randomize_brk +#define ARCH_HAS_SETUP_ADDITIONAL_PAGES 1 +struct linux_binprm; +int arch_setup_additional_pages(struct linux_binprm *, int); + #endif diff --git a/arch/arm/include/asm/mmu.h b/arch/arm/include/asm/mmu.h index e3d5554..7345e37 100644 --- a/arch/arm/include/asm/mmu.h +++ b/arch/arm/include/asm/mmu.h @@ -8,6 +8,7 @@ typedef struct { atomic64_t id; #endif unsigned int vmalloc_seq; + unsigned long sigpage; } mm_context_t; #ifdef CONFIG_CPU_HAS_ASID diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c index d3ca4f6..566d0d7 100644 --- a/arch/arm/kernel/process.c +++ b/arch/arm/kernel/process.c @@ -428,8 +428,8 @@ unsigned long arch_randomize_brk(struct mm_struct *mm) #ifdef CONFIG_MMU /* * The vectors page is always readable from user space for the - * atomic helpers and the signal restart code. Insert it into the - * gate_vma so that it is visible through ptrace and /proc/<pid>/mem. + * atomic helpers. Insert it into the gate_vma so that it is visible + * through ptrace and /proc/<pid>/mem. */ static struct vm_area_struct gate_vma = { .vm_start = 0xffff0000, @@ -461,6 +461,40 @@ int in_gate_area_no_mm(unsigned long addr) const char *arch_vma_name(struct vm_area_struct *vma) { - return (vma == &gate_vma) ? "[vectors]" : NULL; + return (vma == &gate_vma) ? "[vectors]" : + (vma->vm_mm && vma->vm_start == vma->vm_mm->context.sigpage) ? + "[sigpage]" : NULL; +} + +extern struct page *get_signal_page(void); + +int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp) +{ + struct mm_struct *mm = current->mm; + struct page *page; + unsigned long addr; + int ret; + + page = get_signal_page(); + if (!page) + return -ENOMEM; + + down_write(&mm->mmap_sem); + addr = get_unmapped_area(NULL, 0, PAGE_SIZE, 0, 0); + if (IS_ERR_VALUE(addr)) { + ret = addr; + goto up_fail; + } + + ret = install_special_mapping(mm, addr, PAGE_SIZE, + VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC, + &page); + + if (ret == 0) + mm->context.sigpage = addr; + + up_fail: + up_write(&mm->mmap_sem); + return ret; } #endif diff --git a/arch/arm/kernel/signal.c b/arch/arm/kernel/signal.c index 1c16c35..0f17e06 100644 --- a/arch/arm/kernel/signal.c +++ b/arch/arm/kernel/signal.c @@ -8,6 +8,7 @@ * published by the Free Software Foundation. */ #include <linux/errno.h> +#include <linux/random.h> #include <linux/signal.h> #include <linux/personality.h> #include <linux/uaccess.h> @@ -15,12 +16,11 @@ #include <asm/elf.h> #include <asm/cacheflush.h> +#include <asm/traps.h> #include <asm/ucontext.h> #include <asm/unistd.h> #include <asm/vfp.h> -#include "signal.h" - /* * For ARM syscalls, we encode the syscall number into the instruction. */ @@ -40,11 +40,13 @@ #define SWI_THUMB_SIGRETURN (0xdf00 << 16 | 0x2700 | (__NR_sigreturn - __NR_SYSCALL_BASE)) #define SWI_THUMB_RT_SIGRETURN (0xdf00 << 16 | 0x2700 | (__NR_rt_sigreturn - __NR_SYSCALL_BASE)) -const unsigned long sigreturn_codes[7] = { +static const unsigned long sigreturn_codes[7] = { MOV_R7_NR_SIGRETURN, SWI_SYS_SIGRETURN, SWI_THUMB_SIGRETURN, MOV_R7_NR_RT_SIGRETURN, SWI_SYS_RT_SIGRETURN, SWI_THUMB_RT_SIGRETURN, }; +static unsigned long signal_return_offset; + #ifdef CONFIG_CRUNCH static int preserve_crunch_context(struct crunch_sigframe __user *frame) { @@ -401,12 +403,15 @@ setup_return(struct pt_regs *regs, struct ksignal *ksig, return 1; if ((cpsr & MODE32_BIT) && !IS_ENABLED(CONFIG_ARM_MPU)) { + struct mm_struct *mm = current->mm; + /* - * 32-bit code can use the new high-page - * signal return code support except when the MPU has - * protected the vectors page from PL0 + * 32-bit code can use the signal return page + * except when the MPU has protected the vectors + * page from PL0 */ - retcode = KERN_SIGRETURN_CODE + (idx << 2) + thumb; + retcode = mm->context.sigpage + signal_return_offset + + (idx << 2) + thumb; } else { /* * Ensure that the instruction cache sees @@ -608,3 +613,36 @@ do_work_pending(struct pt_regs *regs, unsigned int thread_flags, int syscall) } while (thread_flags & _TIF_WORK_MASK); return 0; } + +static struct page *signal_page; + +struct page *get_signal_page(void) +{ + if (!signal_page) { + unsigned long ptr; + unsigned offset; + void *addr; + + signal_page = alloc_pages(GFP_KERNEL, 0); + + if (!signal_page) + return NULL; + + addr = page_address(signal_page); + + /* Give the signal return code some randomness */ + offset = 0x200 + (get_random_int() & 0x7fc); + signal_return_offset = offset; + + /* + * Copy signal return handlers into the vector page, and + * set sigreturn to be a pointer to these. + */ + memcpy(addr + offset, sigreturn_codes, sizeof(sigreturn_codes)); + + ptr = (unsigned long)addr + offset; + flush_icache_range(ptr, ptr + sizeof(sigreturn_codes)); + } + + return signal_page; +} diff --git a/arch/arm/kernel/signal.h b/arch/arm/kernel/signal.h deleted file mode 100644 index 5ff067b7..0000000 --- a/arch/arm/kernel/signal.h +++ /dev/null @@ -1,12 +0,0 @@ -/* - * linux/arch/arm/kernel/signal.h - * - * Copyright (C) 2005-2009 Russell King. - * - * 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. - */ -#define KERN_SIGRETURN_CODE (CONFIG_VECTORS_BASE + 0x00000500) - -extern const unsigned long sigreturn_codes[7]; diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c index e3ca35c..ab517fc 100644 --- a/arch/arm/kernel/traps.c +++ b/arch/arm/kernel/traps.c @@ -35,8 +35,6 @@ #include <asm/tls.h> #include <asm/system_misc.h> -#include "signal.h" - static const char *handler[]= { "prefetch abort", "data abort", "address exception", "interrupt" }; void *vectors_page; @@ -850,13 +848,6 @@ void __init early_trap_init(void *vectors_base) kuser_init(vectors_base); - /* - * Copy signal return handlers into the vector page, and - * set sigreturn to be a pointer to these. - */ - memcpy((void *)(vectors + KERN_SIGRETURN_CODE - CONFIG_VECTORS_BASE), - sigreturn_codes, sizeof(sigreturn_codes)); - flush_icache_range(vectors, vectors + PAGE_SIZE * 2); modify_domain(DOMAIN_USER, DOMAIN_CLIENT); #else /* ifndef CONFIG_CPU_V7M */ |