The vsyscall code is entry code too, so move it to arch/x86/entry/vsyscall/.
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
#
# Makefile for the x86 low level entry code
#
-obj-y := entry_$(BITS).o thunk_$(BITS).o
+obj-y := entry_$(BITS).o thunk_$(BITS).o syscall_$(BITS).o
+
obj-y += vdso/
+obj-y += vsyscall/
-obj-$(CONFIG_IA32_EMULATION) += ia32entry.o
+obj-$(CONFIG_IA32_EMULATION) += ia32entry.o syscall_32.o
--- /dev/null
+/* System call table for i386. */
+
+#include <linux/linkage.h>
+#include <linux/sys.h>
+#include <linux/cache.h>
+#include <asm/asm-offsets.h>
+
+#ifdef CONFIG_IA32_EMULATION
+#define SYM(sym, compat) compat
+#else
+#define SYM(sym, compat) sym
+#define ia32_sys_call_table sys_call_table
+#define __NR_ia32_syscall_max __NR_syscall_max
+#endif
+
+#define __SYSCALL_I386(nr, sym, compat) extern asmlinkage void SYM(sym, compat)(void) ;
+#include <asm/syscalls_32.h>
+#undef __SYSCALL_I386
+
+#define __SYSCALL_I386(nr, sym, compat) [nr] = SYM(sym, compat),
+
+typedef asmlinkage void (*sys_call_ptr_t)(void);
+
+extern asmlinkage void sys_ni_syscall(void);
+
+__visible const sys_call_ptr_t ia32_sys_call_table[__NR_ia32_syscall_max+1] = {
+ /*
+ * Smells like a compiler bug -- it doesn't work
+ * when the & below is removed.
+ */
+ [0 ... __NR_ia32_syscall_max] = &sys_ni_syscall,
+#include <asm/syscalls_32.h>
+};
--- /dev/null
+/* System call table for x86-64. */
+
+#include <linux/linkage.h>
+#include <linux/sys.h>
+#include <linux/cache.h>
+#include <asm/asm-offsets.h>
+#include <asm/syscall.h>
+
+#define __SYSCALL_COMMON(nr, sym, compat) __SYSCALL_64(nr, sym, compat)
+
+#ifdef CONFIG_X86_X32_ABI
+# define __SYSCALL_X32(nr, sym, compat) __SYSCALL_64(nr, sym, compat)
+#else
+# define __SYSCALL_X32(nr, sym, compat) /* nothing */
+#endif
+
+#define __SYSCALL_64(nr, sym, compat) extern asmlinkage void sym(void) ;
+#include <asm/syscalls_64.h>
+#undef __SYSCALL_64
+
+#define __SYSCALL_64(nr, sym, compat) [nr] = sym,
+
+extern void sys_ni_syscall(void);
+
+asmlinkage const sys_call_ptr_t sys_call_table[__NR_syscall_max+1] = {
+ /*
+ * Smells like a compiler bug -- it doesn't work
+ * when the & below is removed.
+ */
+ [0 ... __NR_syscall_max] = &sys_ni_syscall,
+#include <asm/syscalls_64.h>
+};
--- /dev/null
+#
+# Makefile for the x86 low level vsyscall code
+#
+obj-y := vsyscall_gtod.o
+
+obj-$(CONFIG_X86_VSYSCALL_EMULATION) += vsyscall_64.o vsyscall_emu_64.o
+
--- /dev/null
+/*
+ * Copyright (c) 2012-2014 Andy Lutomirski <luto@amacapital.net>
+ *
+ * Based on the original implementation which is:
+ * Copyright (C) 2001 Andrea Arcangeli <andrea@suse.de> SuSE
+ * Copyright 2003 Andi Kleen, SuSE Labs.
+ *
+ * Parts of the original code have been moved to arch/x86/vdso/vma.c
+ *
+ * This file implements vsyscall emulation. vsyscalls are a legacy ABI:
+ * Userspace can request certain kernel services by calling fixed
+ * addresses. This concept is problematic:
+ *
+ * - It interferes with ASLR.
+ * - It's awkward to write code that lives in kernel addresses but is
+ * callable by userspace at fixed addresses.
+ * - The whole concept is impossible for 32-bit compat userspace.
+ * - UML cannot easily virtualize a vsyscall.
+ *
+ * As of mid-2014, I believe that there is no new userspace code that
+ * will use a vsyscall if the vDSO is present. I hope that there will
+ * soon be no new userspace code that will ever use a vsyscall.
+ *
+ * The code in this file emulates vsyscalls when notified of a page
+ * fault to a vsyscall address.
+ */
+
+#include <linux/kernel.h>
+#include <linux/timer.h>
+#include <linux/syscalls.h>
+#include <linux/ratelimit.h>
+
+#include <asm/vsyscall.h>
+#include <asm/unistd.h>
+#include <asm/fixmap.h>
+#include <asm/traps.h>
+
+#define CREATE_TRACE_POINTS
+#include "vsyscall_trace.h"
+
+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);
+
+static void warn_bad_vsyscall(const char *level, struct pt_regs *regs,
+ const char *message)
+{
+ if (!show_unhandled_signals)
+ return;
+
+ printk_ratelimited("%s%s[%d] %s ip:%lx cs:%lx sp:%lx ax:%lx si:%lx di:%lx\n",
+ level, current->comm, task_pid_nr(current),
+ message, regs->ip, regs->cs,
+ regs->sp, regs->ax, regs->si, regs->di);
+}
+
+static int addr_to_vsyscall_nr(unsigned long addr)
+{
+ int nr;
+
+ if ((addr & ~0xC00UL) != VSYSCALL_ADDR)
+ return -EINVAL;
+
+ nr = (addr & 0xC00UL) >> 10;
+ if (nr >= 3)
+ return -EINVAL;
+
+ return nr;
+}
+
+static bool write_ok_or_segv(unsigned long ptr, size_t size)
+{
+ /*
+ * XXX: if access_ok, get_user, and put_user handled
+ * sig_on_uaccess_error, this could go away.
+ */
+
+ if (!access_ok(VERIFY_WRITE, (void __user *)ptr, size)) {
+ siginfo_t info;
+ struct thread_struct *thread = ¤t->thread;
+
+ thread->error_code = 6; /* user fault, no page, write */
+ thread->cr2 = ptr;
+ thread->trap_nr = X86_TRAP_PF;
+
+ memset(&info, 0, sizeof(info));
+ info.si_signo = SIGSEGV;
+ info.si_errno = 0;
+ info.si_code = SEGV_MAPERR;
+ info.si_addr = (void __user *)ptr;
+
+ force_sig_info(SIGSEGV, &info, current);
+ return false;
+ } else {
+ return true;
+ }
+}
+
+bool emulate_vsyscall(struct pt_regs *regs, unsigned long address)
+{
+ struct task_struct *tsk;
+ unsigned long caller;
+ int vsyscall_nr, syscall_nr, tmp;
+ int prev_sig_on_uaccess_error;
+ long ret;
+
+ /*
+ * 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.
+ */
+
+ WARN_ON_ONCE(address != regs->ip);
+
+ if (vsyscall_mode == NONE) {
+ warn_bad_vsyscall(KERN_INFO, regs,
+ "vsyscall attempted with vsyscall=none");
+ return false;
+ }
+
+ vsyscall_nr = addr_to_vsyscall_nr(address);
+
+ trace_emulate_vsyscall(vsyscall_nr);
+
+ if (vsyscall_nr < 0) {
+ warn_bad_vsyscall(KERN_WARNING, regs,
+ "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,
+ "vsyscall with bad stack (exploit attempt?)");
+ goto sigsegv;
+ }
+
+ tsk = current;
+
+ /*
+ * Check for access_ok violations and find the syscall nr.
+ *
+ * NULL is a valid user pointer (in the access_ok sense) on 32-bit and
+ * 64-bit, so we don't need to special-case it here. For all the
+ * vsyscalls, NULL means "don't write anything" not "write it at
+ * address 0".
+ */
+ switch (vsyscall_nr) {
+ case 0:
+ if (!write_ok_or_segv(regs->di, sizeof(struct timeval)) ||
+ !write_ok_or_segv(regs->si, sizeof(struct timezone))) {
+ ret = -EFAULT;
+ goto check_fault;
+ }
+
+ syscall_nr = __NR_gettimeofday;
+ break;
+
+ case 1:
+ if (!write_ok_or_segv(regs->di, sizeof(time_t))) {
+ ret = -EFAULT;
+ goto check_fault;
+ }
+
+ syscall_nr = __NR_time;
+ break;
+
+ case 2:
+ if (!write_ok_or_segv(regs->di, sizeof(unsigned)) ||
+ !write_ok_or_segv(regs->si, sizeof(unsigned))) {
+ ret = -EFAULT;
+ goto check_fault;
+ }
+
+ syscall_nr = __NR_getcpu;
+ break;
+ }
+
+ /*
+ * Handle seccomp. regs->ip must be the original value.
+ * See seccomp_send_sigsys and Documentation/prctl/seccomp_filter.txt.
+ *
+ * We could optimize the seccomp disabled case, but performance
+ * here doesn't matter.
+ */
+ regs->orig_ax = syscall_nr;
+ regs->ax = -ENOSYS;
+ tmp = secure_computing();
+ if ((!tmp && regs->orig_ax != syscall_nr) || regs->ip != address) {
+ warn_bad_vsyscall(KERN_DEBUG, regs,
+ "seccomp tried to change syscall nr or ip");
+ do_exit(SIGSYS);
+ }
+ regs->orig_ax = -1;
+ if (tmp)
+ goto do_ret; /* skip requested */
+
+ /*
+ * With a real vsyscall, page faults cause SIGSEGV. We want to
+ * preserve that behavior to make writing exploits harder.
+ */
+ prev_sig_on_uaccess_error = current_thread_info()->sig_on_uaccess_error;
+ current_thread_info()->sig_on_uaccess_error = 1;
+
+ ret = -EFAULT;
+ switch (vsyscall_nr) {
+ case 0:
+ ret = sys_gettimeofday(
+ (struct timeval __user *)regs->di,
+ (struct timezone __user *)regs->si);
+ break;
+
+ case 1:
+ ret = sys_time((time_t __user *)regs->di);
+ break;
+
+ case 2:
+ ret = sys_getcpu((unsigned __user *)regs->di,
+ (unsigned __user *)regs->si,
+ NULL);
+ break;
+ }
+
+ current_thread_info()->sig_on_uaccess_error = prev_sig_on_uaccess_error;
+
+check_fault:
+ if (ret == -EFAULT) {
+ /* Bad news -- userspace fed a bad pointer to a vsyscall. */
+ warn_bad_vsyscall(KERN_INFO, regs,
+ "vsyscall fault (exploit attempt?)");
+
+ /*
+ * If we failed to generate a signal for any reason,
+ * generate one here. (This should be impossible.)
+ */
+ if (WARN_ON_ONCE(!sigismember(&tsk->pending.signal, SIGBUS) &&
+ !sigismember(&tsk->pending.signal, SIGSEGV)))
+ goto sigsegv;
+
+ return true; /* Don't emulate the ret. */
+ }
+
+ regs->ax = ret;
+
+do_ret:
+ /* Emulate a ret instruction. */
+ regs->ip = caller;
+ regs->sp += 8;
+ return true;
+
+sigsegv:
+ force_sig(SIGSEGV, current);
+ return true;
+}
+
+/*
+ * A pseudo VMA to allow ptrace access for the vsyscall page. This only
+ * covers the 64bit vsyscall page now. 32bit has a real VMA now and does
+ * not need special handling anymore:
+ */
+static const char *gate_vma_name(struct vm_area_struct *vma)
+{
+ return "[vsyscall]";
+}
+static struct vm_operations_struct gate_vma_ops = {
+ .name = gate_vma_name,
+};
+static struct vm_area_struct gate_vma = {
+ .vm_start = VSYSCALL_ADDR,
+ .vm_end = VSYSCALL_ADDR + PAGE_SIZE,
+ .vm_page_prot = PAGE_READONLY_EXEC,
+ .vm_flags = VM_READ | VM_EXEC,
+ .vm_ops = &gate_vma_ops,
+};
+
+struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
+{
+#ifdef CONFIG_IA32_EMULATION
+ if (!mm || mm->context.ia32_compat)
+ return NULL;
+#endif
+ if (vsyscall_mode == NONE)
+ return NULL;
+ return &gate_vma;
+}
+
+int in_gate_area(struct mm_struct *mm, unsigned long addr)
+{
+ struct vm_area_struct *vma = get_gate_vma(mm);
+
+ if (!vma)
+ return 0;
+
+ return (addr >= vma->vm_start) && (addr < vma->vm_end);
+}
+
+/*
+ * Use this when you have no reliable mm, typically from interrupt
+ * context. It is less reliable than using a task's mm and may give
+ * false positives.
+ */
+int in_gate_area_no_mm(unsigned long addr)
+{
+ return vsyscall_mode != NONE && (addr & PAGE_MASK) == VSYSCALL_ADDR;
+}
+
+void __init map_vsyscall(void)
+{
+ extern char __vsyscall_page;
+ unsigned long physaddr_vsyscall = __pa_symbol(&__vsyscall_page);
+
+ if (vsyscall_mode != NONE)
+ __set_fixmap(VSYSCALL_PAGE, physaddr_vsyscall,
+ vsyscall_mode == NATIVE
+ ? PAGE_KERNEL_VSYSCALL
+ : PAGE_KERNEL_VVAR);
+
+ BUILD_BUG_ON((unsigned long)__fix_to_virt(VSYSCALL_PAGE) !=
+ (unsigned long)VSYSCALL_ADDR);
+}
--- /dev/null
+/*
+ * vsyscall_emu_64.S: Vsyscall emulation page
+ *
+ * Copyright (c) 2011 Andy Lutomirski
+ *
+ * Subject to the GNU General Public License, version 2
+ */
+
+#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
+
+ .balign 1024, 0xcc
+ mov $__NR_time, %rax
+ syscall
+ ret
+
+ .balign 1024, 0xcc
+ mov $__NR_getcpu, %rax
+ syscall
+ ret
+
+ .balign 4096, 0xcc
+
+ .size __vsyscall_page, 4096
--- /dev/null
+/*
+ * Copyright (C) 2001 Andrea Arcangeli <andrea@suse.de> SuSE
+ * Copyright 2003 Andi Kleen, SuSE Labs.
+ *
+ * Modified for x86 32 bit architecture by
+ * Stefani Seibold <stefani@seibold.net>
+ * sponsored by Rohde & Schwarz GmbH & Co. KG Munich/Germany
+ *
+ * Thanks to hpa@transmeta.com for some useful hint.
+ * Special thanks to Ingo Molnar for his early experience with
+ * a different vsyscall implementation for Linux/IA32 and for the name.
+ *
+ */
+
+#include <linux/timekeeper_internal.h>
+#include <asm/vgtod.h>
+#include <asm/vvar.h>
+
+DEFINE_VVAR(struct vsyscall_gtod_data, vsyscall_gtod_data);
+
+void update_vsyscall_tz(void)
+{
+ vsyscall_gtod_data.tz_minuteswest = sys_tz.tz_minuteswest;
+ vsyscall_gtod_data.tz_dsttime = sys_tz.tz_dsttime;
+}
+
+void update_vsyscall(struct timekeeper *tk)
+{
+ struct vsyscall_gtod_data *vdata = &vsyscall_gtod_data;
+
+ gtod_write_begin(vdata);
+
+ /* copy vsyscall data */
+ vdata->vclock_mode = tk->tkr_mono.clock->archdata.vclock_mode;
+ vdata->cycle_last = tk->tkr_mono.cycle_last;
+ vdata->mask = tk->tkr_mono.mask;
+ vdata->mult = tk->tkr_mono.mult;
+ vdata->shift = tk->tkr_mono.shift;
+
+ vdata->wall_time_sec = tk->xtime_sec;
+ vdata->wall_time_snsec = tk->tkr_mono.xtime_nsec;
+
+ vdata->monotonic_time_sec = tk->xtime_sec
+ + tk->wall_to_monotonic.tv_sec;
+ vdata->monotonic_time_snsec = tk->tkr_mono.xtime_nsec
+ + ((u64)tk->wall_to_monotonic.tv_nsec
+ << tk->tkr_mono.shift);
+ while (vdata->monotonic_time_snsec >=
+ (((u64)NSEC_PER_SEC) << tk->tkr_mono.shift)) {
+ vdata->monotonic_time_snsec -=
+ ((u64)NSEC_PER_SEC) << tk->tkr_mono.shift;
+ vdata->monotonic_time_sec++;
+ }
+
+ vdata->wall_time_coarse_sec = tk->xtime_sec;
+ vdata->wall_time_coarse_nsec = (long)(tk->tkr_mono.xtime_nsec >>
+ tk->tkr_mono.shift);
+
+ vdata->monotonic_time_coarse_sec =
+ vdata->wall_time_coarse_sec + tk->wall_to_monotonic.tv_sec;
+ vdata->monotonic_time_coarse_nsec =
+ vdata->wall_time_coarse_nsec + tk->wall_to_monotonic.tv_nsec;
+
+ while (vdata->monotonic_time_coarse_nsec >= NSEC_PER_SEC) {
+ vdata->monotonic_time_coarse_nsec -= NSEC_PER_SEC;
+ vdata->monotonic_time_coarse_sec++;
+ }
+
+ gtod_write_end(vdata);
+}
--- /dev/null
+#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/entry/vsyscall/
+#define TRACE_INCLUDE_FILE vsyscall_trace
+#include <trace/define_trace.h>
obj-$(CONFIG_X86_32) += i386_ksyms_32.o
obj-$(CONFIG_X86_64) += sys_x86_64.o x8664_ksyms_64.o
obj-$(CONFIG_X86_64) += mcount_64.o
-obj-y += syscall_$(BITS).o vsyscall_gtod.o
-obj-$(CONFIG_IA32_EMULATION) += syscall_32.o
-obj-$(CONFIG_X86_VSYSCALL_EMULATION) += vsyscall_64.o vsyscall_emu_64.o
obj-$(CONFIG_X86_ESPFIX64) += espfix_64.o
obj-$(CONFIG_SYSFS) += ksysfs.o
obj-y += bootflag.o e820.o
+++ /dev/null
-/* System call table for i386. */
-
-#include <linux/linkage.h>
-#include <linux/sys.h>
-#include <linux/cache.h>
-#include <asm/asm-offsets.h>
-
-#ifdef CONFIG_IA32_EMULATION
-#define SYM(sym, compat) compat
-#else
-#define SYM(sym, compat) sym
-#define ia32_sys_call_table sys_call_table
-#define __NR_ia32_syscall_max __NR_syscall_max
-#endif
-
-#define __SYSCALL_I386(nr, sym, compat) extern asmlinkage void SYM(sym, compat)(void) ;
-#include <asm/syscalls_32.h>
-#undef __SYSCALL_I386
-
-#define __SYSCALL_I386(nr, sym, compat) [nr] = SYM(sym, compat),
-
-typedef asmlinkage void (*sys_call_ptr_t)(void);
-
-extern asmlinkage void sys_ni_syscall(void);
-
-__visible const sys_call_ptr_t ia32_sys_call_table[__NR_ia32_syscall_max+1] = {
- /*
- * Smells like a compiler bug -- it doesn't work
- * when the & below is removed.
- */
- [0 ... __NR_ia32_syscall_max] = &sys_ni_syscall,
-#include <asm/syscalls_32.h>
-};
+++ /dev/null
-/* System call table for x86-64. */
-
-#include <linux/linkage.h>
-#include <linux/sys.h>
-#include <linux/cache.h>
-#include <asm/asm-offsets.h>
-#include <asm/syscall.h>
-
-#define __SYSCALL_COMMON(nr, sym, compat) __SYSCALL_64(nr, sym, compat)
-
-#ifdef CONFIG_X86_X32_ABI
-# define __SYSCALL_X32(nr, sym, compat) __SYSCALL_64(nr, sym, compat)
-#else
-# define __SYSCALL_X32(nr, sym, compat) /* nothing */
-#endif
-
-#define __SYSCALL_64(nr, sym, compat) extern asmlinkage void sym(void) ;
-#include <asm/syscalls_64.h>
-#undef __SYSCALL_64
-
-#define __SYSCALL_64(nr, sym, compat) [nr] = sym,
-
-extern void sys_ni_syscall(void);
-
-asmlinkage const sys_call_ptr_t sys_call_table[__NR_syscall_max+1] = {
- /*
- * Smells like a compiler bug -- it doesn't work
- * when the & below is removed.
- */
- [0 ... __NR_syscall_max] = &sys_ni_syscall,
-#include <asm/syscalls_64.h>
-};
+++ /dev/null
-/*
- * Copyright (c) 2012-2014 Andy Lutomirski <luto@amacapital.net>
- *
- * Based on the original implementation which is:
- * Copyright (C) 2001 Andrea Arcangeli <andrea@suse.de> SuSE
- * Copyright 2003 Andi Kleen, SuSE Labs.
- *
- * Parts of the original code have been moved to arch/x86/vdso/vma.c
- *
- * This file implements vsyscall emulation. vsyscalls are a legacy ABI:
- * Userspace can request certain kernel services by calling fixed
- * addresses. This concept is problematic:
- *
- * - It interferes with ASLR.
- * - It's awkward to write code that lives in kernel addresses but is
- * callable by userspace at fixed addresses.
- * - The whole concept is impossible for 32-bit compat userspace.
- * - UML cannot easily virtualize a vsyscall.
- *
- * As of mid-2014, I believe that there is no new userspace code that
- * will use a vsyscall if the vDSO is present. I hope that there will
- * soon be no new userspace code that will ever use a vsyscall.
- *
- * The code in this file emulates vsyscalls when notified of a page
- * fault to a vsyscall address.
- */
-
-#include <linux/kernel.h>
-#include <linux/timer.h>
-#include <linux/syscalls.h>
-#include <linux/ratelimit.h>
-
-#include <asm/vsyscall.h>
-#include <asm/unistd.h>
-#include <asm/fixmap.h>
-#include <asm/traps.h>
-
-#define CREATE_TRACE_POINTS
-#include "vsyscall_trace.h"
-
-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);
-
-static void warn_bad_vsyscall(const char *level, struct pt_regs *regs,
- const char *message)
-{
- if (!show_unhandled_signals)
- return;
-
- printk_ratelimited("%s%s[%d] %s ip:%lx cs:%lx sp:%lx ax:%lx si:%lx di:%lx\n",
- level, current->comm, task_pid_nr(current),
- message, regs->ip, regs->cs,
- regs->sp, regs->ax, regs->si, regs->di);
-}
-
-static int addr_to_vsyscall_nr(unsigned long addr)
-{
- int nr;
-
- if ((addr & ~0xC00UL) != VSYSCALL_ADDR)
- return -EINVAL;
-
- nr = (addr & 0xC00UL) >> 10;
- if (nr >= 3)
- return -EINVAL;
-
- return nr;
-}
-
-static bool write_ok_or_segv(unsigned long ptr, size_t size)
-{
- /*
- * XXX: if access_ok, get_user, and put_user handled
- * sig_on_uaccess_error, this could go away.
- */
-
- if (!access_ok(VERIFY_WRITE, (void __user *)ptr, size)) {
- siginfo_t info;
- struct thread_struct *thread = ¤t->thread;
-
- thread->error_code = 6; /* user fault, no page, write */
- thread->cr2 = ptr;
- thread->trap_nr = X86_TRAP_PF;
-
- memset(&info, 0, sizeof(info));
- info.si_signo = SIGSEGV;
- info.si_errno = 0;
- info.si_code = SEGV_MAPERR;
- info.si_addr = (void __user *)ptr;
-
- force_sig_info(SIGSEGV, &info, current);
- return false;
- } else {
- return true;
- }
-}
-
-bool emulate_vsyscall(struct pt_regs *regs, unsigned long address)
-{
- struct task_struct *tsk;
- unsigned long caller;
- int vsyscall_nr, syscall_nr, tmp;
- int prev_sig_on_uaccess_error;
- long ret;
-
- /*
- * 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.
- */
-
- WARN_ON_ONCE(address != regs->ip);
-
- if (vsyscall_mode == NONE) {
- warn_bad_vsyscall(KERN_INFO, regs,
- "vsyscall attempted with vsyscall=none");
- return false;
- }
-
- vsyscall_nr = addr_to_vsyscall_nr(address);
-
- trace_emulate_vsyscall(vsyscall_nr);
-
- if (vsyscall_nr < 0) {
- warn_bad_vsyscall(KERN_WARNING, regs,
- "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,
- "vsyscall with bad stack (exploit attempt?)");
- goto sigsegv;
- }
-
- tsk = current;
-
- /*
- * Check for access_ok violations and find the syscall nr.
- *
- * NULL is a valid user pointer (in the access_ok sense) on 32-bit and
- * 64-bit, so we don't need to special-case it here. For all the
- * vsyscalls, NULL means "don't write anything" not "write it at
- * address 0".
- */
- switch (vsyscall_nr) {
- case 0:
- if (!write_ok_or_segv(regs->di, sizeof(struct timeval)) ||
- !write_ok_or_segv(regs->si, sizeof(struct timezone))) {
- ret = -EFAULT;
- goto check_fault;
- }
-
- syscall_nr = __NR_gettimeofday;
- break;
-
- case 1:
- if (!write_ok_or_segv(regs->di, sizeof(time_t))) {
- ret = -EFAULT;
- goto check_fault;
- }
-
- syscall_nr = __NR_time;
- break;
-
- case 2:
- if (!write_ok_or_segv(regs->di, sizeof(unsigned)) ||
- !write_ok_or_segv(regs->si, sizeof(unsigned))) {
- ret = -EFAULT;
- goto check_fault;
- }
-
- syscall_nr = __NR_getcpu;
- break;
- }
-
- /*
- * Handle seccomp. regs->ip must be the original value.
- * See seccomp_send_sigsys and Documentation/prctl/seccomp_filter.txt.
- *
- * We could optimize the seccomp disabled case, but performance
- * here doesn't matter.
- */
- regs->orig_ax = syscall_nr;
- regs->ax = -ENOSYS;
- tmp = secure_computing();
- if ((!tmp && regs->orig_ax != syscall_nr) || regs->ip != address) {
- warn_bad_vsyscall(KERN_DEBUG, regs,
- "seccomp tried to change syscall nr or ip");
- do_exit(SIGSYS);
- }
- regs->orig_ax = -1;
- if (tmp)
- goto do_ret; /* skip requested */
-
- /*
- * With a real vsyscall, page faults cause SIGSEGV. We want to
- * preserve that behavior to make writing exploits harder.
- */
- prev_sig_on_uaccess_error = current_thread_info()->sig_on_uaccess_error;
- current_thread_info()->sig_on_uaccess_error = 1;
-
- ret = -EFAULT;
- switch (vsyscall_nr) {
- case 0:
- ret = sys_gettimeofday(
- (struct timeval __user *)regs->di,
- (struct timezone __user *)regs->si);
- break;
-
- case 1:
- ret = sys_time((time_t __user *)regs->di);
- break;
-
- case 2:
- ret = sys_getcpu((unsigned __user *)regs->di,
- (unsigned __user *)regs->si,
- NULL);
- break;
- }
-
- current_thread_info()->sig_on_uaccess_error = prev_sig_on_uaccess_error;
-
-check_fault:
- if (ret == -EFAULT) {
- /* Bad news -- userspace fed a bad pointer to a vsyscall. */
- warn_bad_vsyscall(KERN_INFO, regs,
- "vsyscall fault (exploit attempt?)");
-
- /*
- * If we failed to generate a signal for any reason,
- * generate one here. (This should be impossible.)
- */
- if (WARN_ON_ONCE(!sigismember(&tsk->pending.signal, SIGBUS) &&
- !sigismember(&tsk->pending.signal, SIGSEGV)))
- goto sigsegv;
-
- return true; /* Don't emulate the ret. */
- }
-
- regs->ax = ret;
-
-do_ret:
- /* Emulate a ret instruction. */
- regs->ip = caller;
- regs->sp += 8;
- return true;
-
-sigsegv:
- force_sig(SIGSEGV, current);
- return true;
-}
-
-/*
- * A pseudo VMA to allow ptrace access for the vsyscall page. This only
- * covers the 64bit vsyscall page now. 32bit has a real VMA now and does
- * not need special handling anymore:
- */
-static const char *gate_vma_name(struct vm_area_struct *vma)
-{
- return "[vsyscall]";
-}
-static struct vm_operations_struct gate_vma_ops = {
- .name = gate_vma_name,
-};
-static struct vm_area_struct gate_vma = {
- .vm_start = VSYSCALL_ADDR,
- .vm_end = VSYSCALL_ADDR + PAGE_SIZE,
- .vm_page_prot = PAGE_READONLY_EXEC,
- .vm_flags = VM_READ | VM_EXEC,
- .vm_ops = &gate_vma_ops,
-};
-
-struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
-{
-#ifdef CONFIG_IA32_EMULATION
- if (!mm || mm->context.ia32_compat)
- return NULL;
-#endif
- if (vsyscall_mode == NONE)
- return NULL;
- return &gate_vma;
-}
-
-int in_gate_area(struct mm_struct *mm, unsigned long addr)
-{
- struct vm_area_struct *vma = get_gate_vma(mm);
-
- if (!vma)
- return 0;
-
- return (addr >= vma->vm_start) && (addr < vma->vm_end);
-}
-
-/*
- * Use this when you have no reliable mm, typically from interrupt
- * context. It is less reliable than using a task's mm and may give
- * false positives.
- */
-int in_gate_area_no_mm(unsigned long addr)
-{
- return vsyscall_mode != NONE && (addr & PAGE_MASK) == VSYSCALL_ADDR;
-}
-
-void __init map_vsyscall(void)
-{
- extern char __vsyscall_page;
- unsigned long physaddr_vsyscall = __pa_symbol(&__vsyscall_page);
-
- if (vsyscall_mode != NONE)
- __set_fixmap(VSYSCALL_PAGE, physaddr_vsyscall,
- vsyscall_mode == NATIVE
- ? PAGE_KERNEL_VSYSCALL
- : PAGE_KERNEL_VVAR);
-
- BUILD_BUG_ON((unsigned long)__fix_to_virt(VSYSCALL_PAGE) !=
- (unsigned long)VSYSCALL_ADDR);
-}
+++ /dev/null
-/*
- * vsyscall_emu_64.S: Vsyscall emulation page
- *
- * Copyright (c) 2011 Andy Lutomirski
- *
- * Subject to the GNU General Public License, version 2
- */
-
-#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
-
- .balign 1024, 0xcc
- mov $__NR_time, %rax
- syscall
- ret
-
- .balign 1024, 0xcc
- mov $__NR_getcpu, %rax
- syscall
- ret
-
- .balign 4096, 0xcc
-
- .size __vsyscall_page, 4096
+++ /dev/null
-/*
- * Copyright (C) 2001 Andrea Arcangeli <andrea@suse.de> SuSE
- * Copyright 2003 Andi Kleen, SuSE Labs.
- *
- * Modified for x86 32 bit architecture by
- * Stefani Seibold <stefani@seibold.net>
- * sponsored by Rohde & Schwarz GmbH & Co. KG Munich/Germany
- *
- * Thanks to hpa@transmeta.com for some useful hint.
- * Special thanks to Ingo Molnar for his early experience with
- * a different vsyscall implementation for Linux/IA32 and for the name.
- *
- */
-
-#include <linux/timekeeper_internal.h>
-#include <asm/vgtod.h>
-#include <asm/vvar.h>
-
-DEFINE_VVAR(struct vsyscall_gtod_data, vsyscall_gtod_data);
-
-void update_vsyscall_tz(void)
-{
- vsyscall_gtod_data.tz_minuteswest = sys_tz.tz_minuteswest;
- vsyscall_gtod_data.tz_dsttime = sys_tz.tz_dsttime;
-}
-
-void update_vsyscall(struct timekeeper *tk)
-{
- struct vsyscall_gtod_data *vdata = &vsyscall_gtod_data;
-
- gtod_write_begin(vdata);
-
- /* copy vsyscall data */
- vdata->vclock_mode = tk->tkr_mono.clock->archdata.vclock_mode;
- vdata->cycle_last = tk->tkr_mono.cycle_last;
- vdata->mask = tk->tkr_mono.mask;
- vdata->mult = tk->tkr_mono.mult;
- vdata->shift = tk->tkr_mono.shift;
-
- vdata->wall_time_sec = tk->xtime_sec;
- vdata->wall_time_snsec = tk->tkr_mono.xtime_nsec;
-
- vdata->monotonic_time_sec = tk->xtime_sec
- + tk->wall_to_monotonic.tv_sec;
- vdata->monotonic_time_snsec = tk->tkr_mono.xtime_nsec
- + ((u64)tk->wall_to_monotonic.tv_nsec
- << tk->tkr_mono.shift);
- while (vdata->monotonic_time_snsec >=
- (((u64)NSEC_PER_SEC) << tk->tkr_mono.shift)) {
- vdata->monotonic_time_snsec -=
- ((u64)NSEC_PER_SEC) << tk->tkr_mono.shift;
- vdata->monotonic_time_sec++;
- }
-
- vdata->wall_time_coarse_sec = tk->xtime_sec;
- vdata->wall_time_coarse_nsec = (long)(tk->tkr_mono.xtime_nsec >>
- tk->tkr_mono.shift);
-
- vdata->monotonic_time_coarse_sec =
- vdata->wall_time_coarse_sec + tk->wall_to_monotonic.tv_sec;
- vdata->monotonic_time_coarse_nsec =
- vdata->wall_time_coarse_nsec + tk->wall_to_monotonic.tv_nsec;
-
- while (vdata->monotonic_time_coarse_nsec >= NSEC_PER_SEC) {
- vdata->monotonic_time_coarse_nsec -= NSEC_PER_SEC;
- vdata->monotonic_time_coarse_sec++;
- }
-
- gtod_write_end(vdata);
-}
+++ /dev/null
-#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>
projects / linux-2.6-block.git / commitdiff