From 087aaffcdf9c91667c93923fbc05fa8fb6bc7d3a Mon Sep 17 00:00:00 2001 From: Nicolas Pitre Date: Wed, 22 Sep 2010 18:34:36 -0400 Subject: ARM: implement CONFIG_STRICT_DEVMEM by disabling access to RAM via /dev/mem There are very few legitimate use cases, if any, for directly accessing system RAM through /dev/mem. So let's mimic what they do on x86 and forbid it when CONFIG_STRICT_DEVMEM is turned on. Signed-off-by: Nicolas Pitre --- arch/arm/include/asm/io.h | 1 + 1 file changed, 1 insertion(+) (limited to 'arch/arm/include/asm') diff --git a/arch/arm/include/asm/io.h b/arch/arm/include/asm/io.h index 1261b1f9..815efa2 100644 --- a/arch/arm/include/asm/io.h +++ b/arch/arm/include/asm/io.h @@ -294,6 +294,7 @@ extern void pci_iounmap(struct pci_dev *dev, void __iomem *addr); #define ARCH_HAS_VALID_PHYS_ADDR_RANGE extern int valid_phys_addr_range(unsigned long addr, size_t size); extern int valid_mmap_phys_addr_range(unsigned long pfn, size_t size); +extern int devmem_is_allowed(unsigned long pfn); #endif /* -- cgit v1.1 From 70c70d97809c3cdb8ff04f38ee3718c5385a2a4d Mon Sep 17 00:00:00 2001 From: Nicolas Pitre Date: Thu, 26 Aug 2010 15:08:35 -0700 Subject: ARM: SECCOMP support Signed-off-by: Nicolas Pitre --- arch/arm/include/asm/seccomp.h | 11 +++++++++++ arch/arm/include/asm/thread_info.h | 2 ++ 2 files changed, 13 insertions(+) create mode 100644 arch/arm/include/asm/seccomp.h (limited to 'arch/arm/include/asm') diff --git a/arch/arm/include/asm/seccomp.h b/arch/arm/include/asm/seccomp.h new file mode 100644 index 0000000..52b156b --- /dev/null +++ b/arch/arm/include/asm/seccomp.h @@ -0,0 +1,11 @@ +#ifndef _ASM_ARM_SECCOMP_H +#define _ASM_ARM_SECCOMP_H + +#include + +#define __NR_seccomp_read __NR_read +#define __NR_seccomp_write __NR_write +#define __NR_seccomp_exit __NR_exit +#define __NR_seccomp_sigreturn __NR_rt_sigreturn + +#endif /* _ASM_ARM_SECCOMP_H */ diff --git a/arch/arm/include/asm/thread_info.h b/arch/arm/include/asm/thread_info.h index 763e29f..7b5cc8d 100644 --- a/arch/arm/include/asm/thread_info.h +++ b/arch/arm/include/asm/thread_info.h @@ -144,6 +144,7 @@ extern void vfp_flush_hwstate(struct thread_info *); #define TIF_MEMDIE 18 /* is terminating due to OOM killer */ #define TIF_FREEZE 19 #define TIF_RESTORE_SIGMASK 20 +#define TIF_SECCOMP 21 #define _TIF_SIGPENDING (1 << TIF_SIGPENDING) #define _TIF_NEED_RESCHED (1 << TIF_NEED_RESCHED) @@ -153,6 +154,7 @@ extern void vfp_flush_hwstate(struct thread_info *); #define _TIF_USING_IWMMXT (1 << TIF_USING_IWMMXT) #define _TIF_FREEZE (1 << TIF_FREEZE) #define _TIF_RESTORE_SIGMASK (1 << TIF_RESTORE_SIGMASK) +#define _TIF_SECCOMP (1 << TIF_SECCOMP) /* * Change these and you break ASM code in entry-common.S -- cgit v1.1 From ec706dab290c486837d4a825870ab052bf200279 Mon Sep 17 00:00:00 2001 From: Nicolas Pitre Date: Thu, 26 Aug 2010 23:10:50 -0400 Subject: ARM: add a vma entry for the user accessible vector page The kernel makes the high vector page visible to user space. This page contains (amongst others) small code segments that can be executed in user space. Make this page visible through ptrace and /proc//mem in order to let gdb perform code parsing needed for proper unwinding. For example, the ERESTART_RESTARTBLOCK handler actually has a stack frame -- it returns to a PC value stored on the user's stack. To unwind after a "sleep" system call was interrupted twice, GDB would have to recognize this situation and understand that stack frame layout -- which it currently cannot do. We could fix this by hard-coding addresses in the vector page range into GDB, but that isn't really portable as not all of those addresses are guaranteed to remain stable across kernel releases. And having the gdb process make an exception for this page and get content from its own address space for it looks strange, and it is not future proof either. Being located above PAGE_OFFSET, this vma cannot be deleted by user space code. Signed-off-by: Nicolas Pitre --- arch/arm/include/asm/elf.h | 4 ++++ arch/arm/include/asm/mmu_context.h | 29 ++++++++++++++++++++++++++++- 2 files changed, 32 insertions(+), 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 5747a8b..8bb66bc 100644 --- a/arch/arm/include/asm/elf.h +++ b/arch/arm/include/asm/elf.h @@ -127,4 +127,8 @@ struct mm_struct; extern unsigned long arch_randomize_brk(struct mm_struct *mm); #define arch_randomize_brk arch_randomize_brk +extern int vectors_user_mapping(void); +#define arch_setup_additional_pages(bprm, uses_interp) vectors_user_mapping() +#define ARCH_HAS_SETUP_ADDITIONAL_PAGES + #endif diff --git a/arch/arm/include/asm/mmu_context.h b/arch/arm/include/asm/mmu_context.h index a0b3cac..71605d9 100644 --- a/arch/arm/include/asm/mmu_context.h +++ b/arch/arm/include/asm/mmu_context.h @@ -18,7 +18,6 @@ #include #include #include -#include void __check_kvm_seq(struct mm_struct *mm); @@ -134,4 +133,32 @@ switch_mm(struct mm_struct *prev, struct mm_struct *next, #define deactivate_mm(tsk,mm) do { } while (0) #define activate_mm(prev,next) switch_mm(prev, next, NULL) +/* + * We are inserting a "fake" vma for the user-accessible vector page so + * gdb and friends can get to it through ptrace and /proc//mem. + * But we also want to remove it before the generic code gets to see it + * during process exit or the unmapping of it would cause total havoc. + * (the macro is used as remove_vma() is static to mm/mmap.c) + */ +#define arch_exit_mmap(mm) \ +do { \ + struct vm_area_struct *high_vma = find_vma(mm, 0xffff0000); \ + if (high_vma) { \ + BUG_ON(high_vma->vm_next); /* it should be last */ \ + if (high_vma->vm_prev) \ + high_vma->vm_prev->vm_next = NULL; \ + else \ + mm->mmap = NULL; \ + rb_erase(&high_vma->vm_rb, &mm->mm_rb); \ + mm->mmap_cache = NULL; \ + mm->map_count--; \ + remove_vma(high_vma); \ + } \ +} while (0) + +static inline void arch_dup_mmap(struct mm_struct *oldmm, + struct mm_struct *mm) +{ +} + #endif -- cgit v1.1