diff options
Diffstat (limited to 'arch/x86/kernel')
| -rw-r--r-- | arch/x86/kernel/Makefile | 13 | ||||
| -rw-r--r-- | arch/x86/kernel/entry_64.S | 1 | ||||
| -rw-r--r-- | arch/x86/kernel/paravirt.c | 4 | ||||
| -rw-r--r-- | arch/x86/kernel/step.c | 2 | ||||
| -rw-r--r-- | arch/x86/kernel/traps.c | 6 | ||||
| -rw-r--r-- | arch/x86/kernel/vmlinux.lds.S | 41 | ||||
| -rw-r--r-- | arch/x86/kernel/vsyscall_64.c | 90 | ||||
| -rw-r--r-- | arch/x86/kernel/vsyscall_emu_64.S | 36 | ||||
| -rw-r--r-- | arch/x86/kernel/vsyscall_trace.h | 29 |
9 files changed, 117 insertions, 105 deletions
diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile index 04105574c8e9..82f2912155a5 100644 --- a/arch/x86/kernel/Makefile +++ b/arch/x86/kernel/Makefile @@ -17,19 +17,6 @@ CFLAGS_REMOVE_ftrace.o = -pg CFLAGS_REMOVE_early_printk.o = -pg endif -# -# vsyscalls (which work on the user stack) should have -# no stack-protector checks: -# -nostackp := $(call cc-option, -fno-stack-protector) -CFLAGS_vsyscall_64.o := $(PROFILING) -g0 $(nostackp) -CFLAGS_hpet.o := $(nostackp) -CFLAGS_paravirt.o := $(nostackp) -GCOV_PROFILE_vsyscall_64.o := n -GCOV_PROFILE_hpet.o := n -GCOV_PROFILE_tsc.o := n -GCOV_PROFILE_paravirt.o := n - obj-y := process_$(BITS).o signal.o entry_$(BITS).o obj-y += traps.o irq.o irq_$(BITS).o dumpstack_$(BITS).o obj-y += time.o ioport.o ldt.o dumpstack.o diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S index e13329d800c8..6419bb05ecd5 100644 --- a/arch/x86/kernel/entry_64.S +++ b/arch/x86/kernel/entry_64.S @@ -1111,7 +1111,6 @@ zeroentry spurious_interrupt_bug do_spurious_interrupt_bug zeroentry coprocessor_error do_coprocessor_error errorentry alignment_check do_alignment_check zeroentry simd_coprocessor_error do_simd_coprocessor_error -zeroentry emulate_vsyscall do_emulate_vsyscall /* Reload gs selector with exception handling */ diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c index 613a7931ecc1..d90272e6bc40 100644 --- a/arch/x86/kernel/paravirt.c +++ b/arch/x86/kernel/paravirt.c @@ -307,6 +307,10 @@ struct pv_info pv_info = { .paravirt_enabled = 0, .kernel_rpl = 0, .shared_kernel_pmd = 1, /* Only used when CONFIG_X86_PAE is set */ + +#ifdef CONFIG_X86_64 + .extra_user_64bit_cs = __USER_CS, +#endif }; struct pv_init_ops pv_init_ops = { diff --git a/arch/x86/kernel/step.c b/arch/x86/kernel/step.c index 7977f0cfe339..c346d1161488 100644 --- a/arch/x86/kernel/step.c +++ b/arch/x86/kernel/step.c @@ -74,7 +74,7 @@ static int is_setting_trap_flag(struct task_struct *child, struct pt_regs *regs) #ifdef CONFIG_X86_64 case 0x40 ... 0x4f: - if (regs->cs != __USER_CS) + if (!user_64bit_mode(regs)) /* 32-bit mode: register increment */ return 0; /* 64-bit mode: REX prefix */ diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index 9682ec50180c..6913369c234c 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -872,12 +872,6 @@ void __init trap_init(void) set_bit(SYSCALL_VECTOR, used_vectors); #endif -#ifdef CONFIG_X86_64 - BUG_ON(test_bit(VSYSCALL_EMU_VECTOR, used_vectors)); - set_system_intr_gate(VSYSCALL_EMU_VECTOR, &emulate_vsyscall); - set_bit(VSYSCALL_EMU_VECTOR, used_vectors); -#endif - /* * Should be a barrier for any external CPU state: */ diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S index 4aa9c54a9b76..0f703f10901a 100644 --- a/arch/x86/kernel/vmlinux.lds.S +++ b/arch/x86/kernel/vmlinux.lds.S @@ -71,7 +71,6 @@ PHDRS { text PT_LOAD FLAGS(5); /* R_E */ data PT_LOAD FLAGS(6); /* RW_ */ #ifdef CONFIG_X86_64 - user PT_LOAD FLAGS(5); /* R_E */ #ifdef CONFIG_SMP percpu PT_LOAD FLAGS(6); /* RW_ */ #endif @@ -154,44 +153,16 @@ SECTIONS #ifdef CONFIG_X86_64 -#define VSYSCALL_ADDR (-10*1024*1024) - -#define VLOAD_OFFSET (VSYSCALL_ADDR - __vsyscall_0 + LOAD_OFFSET) -#define VLOAD(x) (ADDR(x) - VLOAD_OFFSET) - -#define VVIRT_OFFSET (VSYSCALL_ADDR - __vsyscall_0) -#define VVIRT(x) (ADDR(x) - VVIRT_OFFSET) - - . = ALIGN(4096); - __vsyscall_0 = .; - - . = VSYSCALL_ADDR; - .vsyscall : AT(VLOAD(.vsyscall)) { - *(.vsyscall_0) - - . = 1024; - *(.vsyscall_1) - - . = 2048; - *(.vsyscall_2) - - . = 4096; /* Pad the whole page. */ - } :user =0xcc - . = ALIGN(__vsyscall_0 + PAGE_SIZE, PAGE_SIZE); - -#undef VSYSCALL_ADDR -#undef VLOAD_OFFSET -#undef VLOAD -#undef VVIRT_OFFSET -#undef VVIRT - + . = ALIGN(PAGE_SIZE); __vvar_page = .; .vvar : AT(ADDR(.vvar) - LOAD_OFFSET) { + /* work around gold bug 13023 */ + __vvar_beginning_hack = .; - /* Place all vvars at the offsets in asm/vvar.h. */ -#define EMIT_VVAR(name, offset) \ - . = offset; \ + /* Place all vvars at the offsets in asm/vvar.h. */ +#define EMIT_VVAR(name, offset) \ + . = __vvar_beginning_hack + offset; \ *(.vvar_ ## name) #define __VVAR_KERNEL_LDS #include <asm/vvar.h> diff --git a/arch/x86/kernel/vsyscall_64.c b/arch/x86/kernel/vsyscall_64.c index dda7dff9cef7..18ae83dd1cd7 100644 --- a/arch/x86/kernel/vsyscall_64.c +++ b/arch/x86/kernel/vsyscall_64.c @@ -18,9 +18,6 @@ * use the vDSO. */ -/* Disable profiling for userspace code: */ -#define DISABLE_BRANCH_PROFILING - #include <linux/time.h> #include <linux/init.h> #include <linux/kernel.h> @@ -50,12 +47,36 @@ #include <asm/vgtod.h> #include <asm/traps.h> +#define CREATE_TRACE_POINTS +#include "vsyscall_trace.h" + DEFINE_VVAR(int, vgetcpu_mode); DEFINE_VVAR(struct vsyscall_gtod_data, vsyscall_gtod_data) = { .lock = __SEQLOCK_UNLOCKED(__vsyscall_gtod_data.lock), }; +static enum { EMULATE, NATIVE, NONE } vsyscall_mode = EMULATE; + +static int __init vsyscall_setup(char *str) +{ + if (str) { + if (!strcmp("emulate", str)) + vsyscall_mode = EMULATE; + else if (!strcmp("native", str)) + vsyscall_mode = NATIVE; + else if (!strcmp("none", str)) + vsyscall_mode = NONE; + else + return -EINVAL; + + return 0; + } + + return -EINVAL; +} +early_param("vsyscall", vsyscall_setup); + void update_vsyscall_tz(void) { unsigned long flags; @@ -100,7 +121,7 @@ static void warn_bad_vsyscall(const char *level, struct pt_regs *regs, printk("%s%s[%d] %s ip:%lx cs:%lx sp:%lx ax:%lx si:%lx di:%lx\n", level, tsk->comm, task_pid_nr(tsk), - message, regs->ip - 2, regs->cs, + message, regs->ip, regs->cs, regs->sp, regs->ax, regs->si, regs->di); } @@ -118,46 +139,39 @@ static int addr_to_vsyscall_nr(unsigned long addr) return nr; } -void dotraplinkage do_emulate_vsyscall(struct pt_regs *regs, long error_code) +bool emulate_vsyscall(struct pt_regs *regs, unsigned long address) { struct task_struct *tsk; unsigned long caller; int vsyscall_nr; long ret; - local_irq_enable(); - /* - * Real 64-bit user mode code has cs == __USER_CS. Anything else - * is bogus. + * No point in checking CS -- the only way to get here is a user mode + * trap to a high address, which means that we're in 64-bit user code. */ - if (regs->cs != __USER_CS) { - /* - * If we trapped from kernel mode, we might as well OOPS now - * instead of returning to some random address and OOPSing - * then. - */ - BUG_ON(!user_mode(regs)); - /* Compat mode and non-compat 32-bit CS should both segfault. */ - warn_bad_vsyscall(KERN_WARNING, regs, - "illegal int 0xcc from 32-bit mode"); - goto sigsegv; + WARN_ON_ONCE(address != regs->ip); + + if (vsyscall_mode == NONE) { + warn_bad_vsyscall(KERN_INFO, regs, + "vsyscall attempted with vsyscall=none"); + return false; } - /* - * x86-ism here: regs->ip points to the instruction after the int 0xcc, - * and int 0xcc is two bytes long. - */ - vsyscall_nr = addr_to_vsyscall_nr(regs->ip - 2); + vsyscall_nr = addr_to_vsyscall_nr(address); + + trace_emulate_vsyscall(vsyscall_nr); + if (vsyscall_nr < 0) { warn_bad_vsyscall(KERN_WARNING, regs, - "illegal int 0xcc (exploit attempt?)"); + "misaligned vsyscall (exploit attempt or buggy program) -- look up the vsyscall kernel parameter if you need a workaround"); goto sigsegv; } if (get_user(caller, (unsigned long __user *)regs->sp) != 0) { - warn_bad_vsyscall(KERN_WARNING, regs, "int 0xcc with bad stack (exploit attempt?)"); + warn_bad_vsyscall(KERN_WARNING, regs, + "vsyscall with bad stack (exploit attempt?)"); goto sigsegv; } @@ -202,13 +216,11 @@ void dotraplinkage do_emulate_vsyscall(struct pt_regs *regs, long error_code) regs->ip = caller; regs->sp += 8; - local_irq_disable(); - return; + return true; sigsegv: - regs->ip -= 2; /* The faulting instruction should be the int 0xcc. */ force_sig(SIGSEGV, current); - local_irq_disable(); + return true; } /* @@ -256,15 +268,21 @@ cpu_vsyscall_notifier(struct notifier_block *n, unsigned long action, void *arg) void __init map_vsyscall(void) { - extern char __vsyscall_0; - unsigned long physaddr_page0 = __pa_symbol(&__vsyscall_0); + extern char __vsyscall_page; + unsigned long physaddr_vsyscall = __pa_symbol(&__vsyscall_page); extern char __vvar_page; unsigned long physaddr_vvar_page = __pa_symbol(&__vvar_page); - /* Note that VSYSCALL_MAPPED_PAGES must agree with the code below. */ - __set_fixmap(VSYSCALL_FIRST_PAGE, physaddr_page0, PAGE_KERNEL_VSYSCALL); + __set_fixmap(VSYSCALL_FIRST_PAGE, physaddr_vsyscall, + vsyscall_mode == NATIVE + ? PAGE_KERNEL_VSYSCALL + : PAGE_KERNEL_VVAR); + BUILD_BUG_ON((unsigned long)__fix_to_virt(VSYSCALL_FIRST_PAGE) != + (unsigned long)VSYSCALL_START); + __set_fixmap(VVAR_PAGE, physaddr_vvar_page, PAGE_KERNEL_VVAR); - BUILD_BUG_ON((unsigned long)__fix_to_virt(VVAR_PAGE) != (unsigned long)VVAR_ADDRESS); + BUILD_BUG_ON((unsigned long)__fix_to_virt(VVAR_PAGE) != + (unsigned long)VVAR_ADDRESS); } static int __init vsyscall_init(void) diff --git a/arch/x86/kernel/vsyscall_emu_64.S b/arch/x86/kernel/vsyscall_emu_64.S index ffa845eae5ca..c9596a9af159 100644 --- a/arch/x86/kernel/vsyscall_emu_64.S +++ b/arch/x86/kernel/vsyscall_emu_64.S @@ -7,21 +7,31 @@ */ #include <linux/linkage.h> + #include <asm/irq_vectors.h> +#include <asm/page_types.h> +#include <asm/unistd_64.h> + +__PAGE_ALIGNED_DATA + .globl __vsyscall_page + .balign PAGE_SIZE, 0xcc + .type __vsyscall_page, @object +__vsyscall_page: + + mov $__NR_gettimeofday, %rax + syscall + ret -/* The unused parts of the page are filled with 0xcc by the linker script. */ + .balign 1024, 0xcc + mov $__NR_time, %rax + syscall + ret -.section .vsyscall_0, "a" -ENTRY(vsyscall_0) - int $VSYSCALL_EMU_VECTOR -END(vsyscall_0) + .balign 1024, 0xcc + mov $__NR_getcpu, %rax + syscall + ret -.section .vsyscall_1, "a" -ENTRY(vsyscall_1) - int $VSYSCALL_EMU_VECTOR -END(vsyscall_1) + .balign 4096, 0xcc -.section .vsyscall_2, "a" -ENTRY(vsyscall_2) - int $VSYSCALL_EMU_VECTOR -END(vsyscall_2) + .size __vsyscall_page, 4096 diff --git a/arch/x86/kernel/vsyscall_trace.h b/arch/x86/kernel/vsyscall_trace.h new file mode 100644 index 000000000000..a8b2edec54fe --- /dev/null +++ b/arch/x86/kernel/vsyscall_trace.h @@ -0,0 +1,29 @@ +#undef TRACE_SYSTEM +#define TRACE_SYSTEM vsyscall + +#if !defined(__VSYSCALL_TRACE_H) || defined(TRACE_HEADER_MULTI_READ) +#define __VSYSCALL_TRACE_H + +#include <linux/tracepoint.h> + +TRACE_EVENT(emulate_vsyscall, + + TP_PROTO(int nr), + + TP_ARGS(nr), + + TP_STRUCT__entry(__field(int, nr)), + + TP_fast_assign( + __entry->nr = nr; + ), + + TP_printk("nr = %d", __entry->nr) +); + +#endif + +#undef TRACE_INCLUDE_PATH +#define TRACE_INCLUDE_PATH ../../arch/x86/kernel +#define TRACE_INCLUDE_FILE vsyscall_trace +#include <trace/define_trace.h> |