[patch 3/3] vdso: randomize the i386 vDSO by moving it into a vma

From: Ingo Molnar
Date: Mon May 22 2006 - 20:01:41 EST

From: Ingo Molnar <mingo@xxxxxxx>

move the i386 VDSO down into a vma and thus randomize it.

besides the security implications, this feature also helps debuggers,
which can COW a vma-backed VDSO just like a normal DSO and can thus do
single-stepping and other debugging features.

It's good for hypervisors (Xen, VMWare) too, which typically live in the
same high-mapped address space as the VDSO, hence whenever the VDSO is
used, they get lots of guest pagefaults and have to fix such guest
accesses up - which slows things down instead of speeding things up
(the primary purpose of the VDSO).

there's a new CONFIG_COMPAT_VDSO (default=y) option, which provides support
for older glibcs that still rely on a prelinked high-mapped VDSO.
Newer distributions (using glibc 2.3.3 or later) can turn this option
off. Turning it off is also recommended for security reasons: attackers
cannot use the predictable high-mapped VDSO page as syscall trampoline
anymore.

there is a new vdso=[0|1] boot option as well, and a runtime
/proc/sys/vm/vdso_enabled sysctl switch, that allows the VDSO
to be turned on/off.

(this version of the VDSO-randomization patch also has working ELF
coredumping, the previous patch crashed in the coredumping code.)

This code is a combined work of the exec-shield VDSO randomization
code and Gerd Hoffmann's hypervisor-centric VDSO patch. Rusty Russell
started this patch and i completed it.

Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
Signed-off-by: Arjan van de Ven <arjan@xxxxxxxxxxxxx>
---
Documentation/kernel-parameters.txt | 4 +
arch/i386/Kconfig | 11 ++
arch/i386/kernel/asm-offsets.c | 4 -
arch/i386/kernel/entry.S | 8 +-
arch/i386/kernel/signal.c | 4 -
arch/i386/kernel/sysenter.c | 131 +++++++++++++++++++++++++++++++++--
arch/i386/kernel/vsyscall-sysenter.S | 4 -
arch/i386/kernel/vsyscall.lds.S | 4 -
fs/proc/task_mmu.c | 30 ++++----
include/asm-i386/elf.h | 53 ++++++++++----
include/asm-i386/fixmap.h | 10 --
include/asm-i386/mmu.h | 1
include/asm-i386/page.h | 6 +
include/asm-i386/thread_info.h | 1
include/linux/sched.h | 1
include/linux/sysctl.h | 1
kernel/sysctl.c | 13 +++
17 files changed, 237 insertions(+), 49 deletions(-)

Index: linux-vdso-rand.q/Documentation/kernel-parameters.txt
===================================================================
--- linux-vdso-rand.q.orig/Documentation/kernel-parameters.txt
+++ linux-vdso-rand.q/Documentation/kernel-parameters.txt
@@ -1652,6 +1652,10 @@ running once the system is up.
usbhid.mousepoll=
[USBHID] The interval which mice are to be polled at.

+ vdso= [IA-32]
+ vdso=1: enable VDSO (default)
+ vdso=0: disable VDSO mapping
+
video= [FB] Frame buffer configuration
See Documentation/fb/modedb.txt.

Index: linux-vdso-rand.q/arch/i386/Kconfig
===================================================================
--- linux-vdso-rand.q.orig/arch/i386/Kconfig
+++ linux-vdso-rand.q/arch/i386/Kconfig
@@ -762,6 +762,17 @@ config HOTPLUG_CPU
enable suspend on SMP systems. CPUs can be controlled through
/sys/devices/system/cpu.

+config COMPAT_VDSO
+ bool "Compat VDSO support"
+ default y
+ help
+ Map the VDSO to the predictable old-style address too.
+ ---help---
+ Say N here if you are running a sufficiently recent glibc
+ version (2.3.3 or later), to remove the high-mapped
+ VDSO mapping and to exclusively use the randomized VDSO.
+
+ If unsure, say Y.

endmenu

Index: linux-vdso-rand.q/arch/i386/kernel/asm-offsets.c
===================================================================
--- linux-vdso-rand.q.orig/arch/i386/kernel/asm-offsets.c
+++ linux-vdso-rand.q/arch/i386/kernel/asm-offsets.c
@@ -13,6 +13,7 @@
#include <asm/fixmap.h>
#include <asm/processor.h>
#include <asm/thread_info.h>
+#include <asm/elf.h>

#define DEFINE(sym, val) \
asm volatile("\n->" #sym " %0 " #val : : "i" (val))
@@ -53,6 +54,7 @@ void foo(void)
OFFSET(TI_preempt_count, thread_info, preempt_count);
OFFSET(TI_addr_limit, thread_info, addr_limit);
OFFSET(TI_restart_block, thread_info, restart_block);
+ OFFSET(TI_sysenter_return, thread_info, sysenter_return);
BLANK();

OFFSET(EXEC_DOMAIN_handler, exec_domain, handler);
@@ -68,5 +70,5 @@ void foo(void)
sizeof(struct tss_struct));

DEFINE(PAGE_SIZE_asm, PAGE_SIZE);
- DEFINE(VSYSCALL_BASE, __fix_to_virt(FIX_VSYSCALL));
+ DEFINE(VDSO_PRELINK, VDSO_PRELINK);
}
Index: linux-vdso-rand.q/arch/i386/kernel/entry.S
===================================================================
--- linux-vdso-rand.q.orig/arch/i386/kernel/entry.S
+++ linux-vdso-rand.q/arch/i386/kernel/entry.S
@@ -184,8 +184,12 @@ sysenter_past_esp:
pushl %ebp
pushfl
pushl $(__USER_CS)
- pushl $SYSENTER_RETURN
-
+ /*
+ * Push current_thread_info()->sysenter_return to the stack.
+ * A tiny bit of offset fixup is necessary - 4*4 means the 4 words
+ * pushed above; +8 corresponds to copy_thread's esp0 setting.
+ */
+ pushl (TI_sysenter_return-THREAD_SIZE+8+4*4)(%esp)
/*
* Load the potential sixth argument from user stack.
* Careful about security.
Index: linux-vdso-rand.q/arch/i386/kernel/signal.c
===================================================================
--- linux-vdso-rand.q.orig/arch/i386/kernel/signal.c
+++ linux-vdso-rand.q/arch/i386/kernel/signal.c
@@ -351,7 +351,7 @@ static int setup_frame(int sig, struct k
goto give_sigsegv;
}

- restorer = &__kernel_sigreturn;
+ restorer = (void *)VDSO_SYM(&__kernel_sigreturn);
if (ka->sa.sa_flags & SA_RESTORER)
restorer = ka->sa.sa_restorer;

@@ -447,7 +447,7 @@ static int setup_rt_frame(int sig, struc
goto give_sigsegv;

/* Set up to return from userspace. */
- restorer = &__kernel_rt_sigreturn;
+ restorer = (void *)VDSO_SYM(&__kernel_rt_sigreturn);
if (ka->sa.sa_flags & SA_RESTORER)
restorer = ka->sa.sa_restorer;
err |= __put_user(restorer, &frame->pretcode);
Index: linux-vdso-rand.q/arch/i386/kernel/sysenter.c
===================================================================
--- linux-vdso-rand.q.orig/arch/i386/kernel/sysenter.c
+++ linux-vdso-rand.q/arch/i386/kernel/sysenter.c
@@ -2,6 +2,8 @@
* linux/arch/i386/kernel/sysenter.c
*
* (C) Copyright 2002 Linus Torvalds
+ * Portions based on the vdso-randomization code from exec-shield:
+ * Copyright(C) 2005-2006, Red Hat, Inc., Ingo Molnar
*
* This file contains the needed initializations to support sysenter.
*/
@@ -13,12 +15,31 @@
#include <linux/gfp.h>
#include <linux/string.h>
#include <linux/elf.h>
+#include <linux/mm.h>
+#include <linux/module.h>

#include <asm/cpufeature.h>
#include <asm/msr.h>
#include <asm/pgtable.h>
#include <asm/unistd.h>

+/*
+ * Should the kernel map a VDSO page into processes and pass its
+ * address down to glibc upon exec()?
+ */
+unsigned int __read_mostly vdso_enabled = 1;
+
+EXPORT_SYMBOL_GPL(vdso_enabled);
+
+static int __init vdso_setup(char *s)
+{
+ vdso_enabled = simple_strtoul(s, NULL, 0);
+
+ return 1;
+}
+
+__setup("vdso=", vdso_setup);
+
extern asmlinkage void sysenter_entry(void);

void enable_sep_cpu(void)
@@ -45,23 +66,125 @@ void enable_sep_cpu(void)
*/
extern const char vsyscall_int80_start, vsyscall_int80_end;
extern const char vsyscall_sysenter_start, vsyscall_sysenter_end;
+static void *syscall_page;

int __init sysenter_setup(void)
{
- void *page = (void *)get_zeroed_page(GFP_ATOMIC);
+ syscall_page = (void *)get_zeroed_page(GFP_ATOMIC);

- __set_fixmap(FIX_VSYSCALL, __pa(page), PAGE_READONLY_EXEC);
+#ifdef CONFIG_COMPAT_VDSO
+ __set_fixmap(FIX_VDSO, __pa(syscall_page), PAGE_READONLY);
+ printk("Compat vDSO mapped to %08lx.\n", __fix_to_virt(FIX_VDSO));
+#else
+ /*
+ * In the non-compat case the ELF coredumping code needs the fixmap:
+ */
+ __set_fixmap(FIX_VDSO, __pa(syscall_page), PAGE_KERNEL_RO);
+#endif

if (!boot_cpu_has(X86_FEATURE_SEP)) {
- memcpy(page,
+ memcpy(syscall_page,
&vsyscall_int80_start,
&vsyscall_int80_end - &vsyscall_int80_start);
return 0;
}

- memcpy(page,
+ memcpy(syscall_page,
&vsyscall_sysenter_start,
&vsyscall_sysenter_end - &vsyscall_sysenter_start);

return 0;
}
+
+static struct page *syscall_nopage(struct vm_area_struct *vma,
+ unsigned long adr, int *type)
+{
+ struct page *p = virt_to_page(adr - vma->vm_start + syscall_page);
+ get_page(p);
+ return p;
+}
+
+/* Prevent VMA merging */
+static void syscall_vma_close(struct vm_area_struct *vma)
+{
+}
+
+static struct vm_operations_struct syscall_vm_ops = {
+ .close = syscall_vma_close,
+ .nopage = syscall_nopage,
+};
+
+/* Defined in vsyscall-sysenter.S */
+extern void SYSENTER_RETURN;
+
+/* Setup a VMA at program startup for the vsyscall page */
+int arch_setup_additional_pages(struct linux_binprm *bprm, int exstack)
+{
+ struct vm_area_struct *vma;
+ struct mm_struct *mm = current->mm;
+ unsigned long addr;
+ int ret;
+
+ 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;
+ }
+
+ vma = kmem_cache_zalloc(vm_area_cachep, SLAB_KERNEL);
+ if (!vma) {
+ ret = -ENOMEM;
+ goto up_fail;
+ }
+
+ vma->vm_start = addr;
+ vma->vm_end = addr + PAGE_SIZE;
+ /* MAYWRITE to allow gdb to COW and set breakpoints */
+ vma->vm_flags = VM_READ|VM_EXEC|VM_MAYREAD|VM_MAYEXEC|VM_MAYWRITE;
+ vma->vm_flags |= mm->def_flags;
+ vma->vm_page_prot = protection_map[vma->vm_flags & 7];
+ vma->vm_ops = &syscall_vm_ops;
+ vma->vm_mm = mm;
+
+ ret = insert_vm_struct(mm, vma);
+ if (ret)
+ goto free_vma;
+
+ current->mm->context.vdso = (void *)addr;
+ current_thread_info()->sysenter_return =
+ (void *)VDSO_SYM(&SYSENTER_RETURN);
+ mm->total_vm++;
+ up_write(&mm->mmap_sem);
+
+ return 0;
+
+free_vma:
+ kmem_cache_free(vm_area_cachep, vma);
+up_fail:
+ up_write(&mm->mmap_sem);
+
+ return ret;
+}
+
+const char *arch_vma_name(struct vm_area_struct *vma)
+{
+ if (vma->vm_mm && vma->vm_start == (long)vma->vm_mm->context.vdso)
+ return "[vdso]";
+ return NULL;
+}
+
+struct vm_area_struct *get_gate_vma(struct task_struct *tsk)
+{
+ return NULL;
+}
+
+int in_gate_area(struct task_struct *task, unsigned long addr)
+{
+ return 0;
+}
+
+int in_gate_area_no_task(unsigned long addr)
+{
+ return 0;
+}
Index: linux-vdso-rand.q/arch/i386/kernel/vsyscall-sysenter.S
===================================================================
--- linux-vdso-rand.q.orig/arch/i386/kernel/vsyscall-sysenter.S
+++ linux-vdso-rand.q/arch/i386/kernel/vsyscall-sysenter.S
@@ -42,10 +42,10 @@ __kernel_vsyscall:
/* 7: align return point with nop's to make disassembly easier */
.space 7,0x90

- /* 14: System call restart point is here! (SYSENTER_RETURN - 2) */
+ /* 14: System call restart point is here! (SYSENTER_RETURN-2) */
jmp .Lenter_kernel
/* 16: System call normal return point is here! */
- .globl SYSENTER_RETURN /* Symbol used by entry.S. */
+ .globl SYSENTER_RETURN /* Symbol used by sysenter.c */
SYSENTER_RETURN:
pop %ebp
.Lpop_ebp:
Index: linux-vdso-rand.q/arch/i386/kernel/vsyscall.lds.S
===================================================================
--- linux-vdso-rand.q.orig/arch/i386/kernel/vsyscall.lds.S
+++ linux-vdso-rand.q/arch/i386/kernel/vsyscall.lds.S
@@ -7,7 +7,7 @@

SECTIONS
{
- . = VSYSCALL_BASE + SIZEOF_HEADERS;
+ . = VDSO_PRELINK + SIZEOF_HEADERS;

.hash : { *(.hash) } :text
.dynsym : { *(.dynsym) }
@@ -20,7 +20,7 @@ SECTIONS
For the layouts to match, we need to skip more than enough
space for the dynamic symbol table et al. If this amount
is insufficient, ld -shared will barf. Just increase it here. */
- . = VSYSCALL_BASE + 0x400;
+ . = VDSO_PRELINK + 0x400;

.text : { *(.text) } :text =0x90909090
.note : { *(.note.*) } :text :note
Index: linux-vdso-rand.q/fs/proc/task_mmu.c
===================================================================
--- linux-vdso-rand.q.orig/fs/proc/task_mmu.c
+++ linux-vdso-rand.q/fs/proc/task_mmu.c
@@ -118,6 +118,11 @@ struct mem_size_stats
unsigned long private_dirty;
};

+__attribute__((weak)) const char *arch_vma_name(struct vm_area_struct *vma)
+{
+ return NULL;
+}
+
static int show_map_internal(struct seq_file *m, void *v, struct mem_size_stats *mss)
{
struct task_struct *task = m->private;
@@ -153,22 +158,23 @@ static int show_map_internal(struct seq_
pad_len_spaces(m, len);
seq_path(m, file->f_vfsmnt, file->f_dentry, "\n");
} else {
- if (mm) {
- if (vma->vm_start <= mm->start_brk &&
+ const char *name = arch_vma_name(vma);
+ if (!name) {
+ if (mm) {
+ if (vma->vm_start <= mm->start_brk &&
vma->vm_end >= mm->brk) {
- pad_len_spaces(m, len);
- seq_puts(m, "[heap]");
- } else {
- if (vma->vm_start <= mm->start_stack &&
- vma->vm_end >= mm->start_stack) {
-
- pad_len_spaces(m, len);
- seq_puts(m, "[stack]");
+ name = "[heap]";
+ } else if (vma->vm_start <= mm->start_stack &&
+ vma->vm_end >= mm->start_stack) {
+ name = "[stack]";
}
+ } else {
+ name = "[vdso]";
}
- } else {
+ }
+ if (name) {
pad_len_spaces(m, len);
- seq_puts(m, "[vdso]");
+ seq_puts(m, name);
}
}
seq_putc(m, '\n');
Index: linux-vdso-rand.q/include/asm-i386/elf.h
===================================================================
--- linux-vdso-rand.q.orig/include/asm-i386/elf.h
+++ linux-vdso-rand.q/include/asm-i386/elf.h
@@ -10,6 +10,7 @@
#include <asm/processor.h>
#include <asm/system.h> /* for savesegment */
#include <asm/auxvec.h>
+#include <asm/desc.h>

#include <linux/utsname.h>

@@ -129,15 +130,41 @@ extern int dump_task_extended_fpu (struc
#define ELF_CORE_COPY_FPREGS(tsk, elf_fpregs) dump_task_fpu(tsk, elf_fpregs)
#define ELF_CORE_COPY_XFPREGS(tsk, elf_xfpregs) dump_task_extended_fpu(tsk, elf_xfpregs)

-#define VSYSCALL_BASE (__fix_to_virt(FIX_VSYSCALL))
-#define VSYSCALL_EHDR ((const struct elfhdr *) VSYSCALL_BASE)
-#define VSYSCALL_ENTRY ((unsigned long) &__kernel_vsyscall)
+#define VDSO_HIGH_BASE (__fix_to_virt(FIX_VDSO))
+#define VDSO_BASE ((unsigned long)current->mm->context.vdso)
+
+#ifdef CONFIG_COMPAT_VDSO
+# define VDSO_COMPAT_BASE VDSO_HIGH_BASE
+# define VDSO_PRELINK VDSO_HIGH_BASE
+#else
+# define VDSO_COMPAT_BASE VDSO_BASE
+# define VDSO_PRELINK 0
+#endif
+
+#define VDSO_COMPAT_SYM(x) \
+ (VDSO_COMPAT_BASE + (unsigned long)(x) - VDSO_PRELINK)
+
+#define VDSO_SYM(x) \
+ (VDSO_BASE + (unsigned long)(x) - VDSO_PRELINK)
+
+#define VDSO_HIGH_EHDR ((const struct elfhdr *) VDSO_HIGH_BASE)
+#define VDSO_EHDR ((const struct elfhdr *) VDSO_COMPAT_BASE)
+
extern void __kernel_vsyscall;

+#define VDSO_ENTRY VDSO_SYM(&__kernel_vsyscall)
+
+#define ARCH_HAS_SETUP_ADDITIONAL_PAGES
+struct linux_binprm;
+extern int arch_setup_additional_pages(struct linux_binprm *bprm,
+ int executable_stack);
+
+extern unsigned int vdso_enabled;
+
#define ARCH_DLINFO \
-do { \
- NEW_AUX_ENT(AT_SYSINFO, VSYSCALL_ENTRY); \
- NEW_AUX_ENT(AT_SYSINFO_EHDR, VSYSCALL_BASE); \
+do if (vdso_enabled) { \
+ NEW_AUX_ENT(AT_SYSINFO, VDSO_ENTRY); \
+ NEW_AUX_ENT(AT_SYSINFO_EHDR, VDSO_COMPAT_BASE); \
} while (0)

/*
@@ -148,15 +175,15 @@ do { \
* Dumping its extra ELF program headers includes all the other information
* a debugger needs to easily find how the vsyscall DSO was being used.
*/
-#define ELF_CORE_EXTRA_PHDRS (VSYSCALL_EHDR->e_phnum)
+#define ELF_CORE_EXTRA_PHDRS (VDSO_HIGH_EHDR->e_phnum)
#define ELF_CORE_WRITE_EXTRA_PHDRS \
do { \
const struct elf_phdr *const vsyscall_phdrs = \
- (const struct elf_phdr *) (VSYSCALL_BASE \
- + VSYSCALL_EHDR->e_phoff); \
+ (const struct elf_phdr *) (VDSO_HIGH_BASE \
+ + VDSO_HIGH_EHDR->e_phoff); \
int i; \
Elf32_Off ofs = 0; \
- for (i = 0; i < VSYSCALL_EHDR->e_phnum; ++i) { \
+ for (i = 0; i < VDSO_HIGH_EHDR->e_phnum; ++i) { \
struct elf_phdr phdr = vsyscall_phdrs[i]; \
if (phdr.p_type == PT_LOAD) { \
BUG_ON(ofs != 0); \
@@ -174,10 +201,10 @@ do { \
#define ELF_CORE_WRITE_EXTRA_DATA \
do { \
const struct elf_phdr *const vsyscall_phdrs = \
- (const struct elf_phdr *) (VSYSCALL_BASE \
- + VSYSCALL_EHDR->e_phoff); \
+ (const struct elf_phdr *) (VDSO_HIGH_BASE \
+ + VDSO_HIGH_EHDR->e_phoff); \
int i; \
- for (i = 0; i < VSYSCALL_EHDR->e_phnum; ++i) { \
+ for (i = 0; i < VDSO_HIGH_EHDR->e_phnum; ++i) { \
if (vsyscall_phdrs[i].p_type == PT_LOAD) \
DUMP_WRITE((void *) vsyscall_phdrs[i].p_vaddr, \
PAGE_ALIGN(vsyscall_phdrs[i].p_memsz)); \
Index: linux-vdso-rand.q/include/asm-i386/fixmap.h
===================================================================
--- linux-vdso-rand.q.orig/include/asm-i386/fixmap.h
+++ linux-vdso-rand.q/include/asm-i386/fixmap.h
@@ -52,7 +52,7 @@
*/
enum fixed_addresses {
FIX_HOLE,
- FIX_VSYSCALL,
+ FIX_VDSO,
#ifdef CONFIG_X86_LOCAL_APIC
FIX_APIC_BASE, /* local (CPU) APIC) -- required for SMP or not */
#endif
@@ -116,14 +116,6 @@ extern void __set_fixmap (enum fixed_add
#define __fix_to_virt(x) (FIXADDR_TOP - ((x) << PAGE_SHIFT))
#define __virt_to_fix(x) ((FIXADDR_TOP - ((x)&PAGE_MASK)) >> PAGE_SHIFT)

-/*
- * This is the range that is readable by user mode, and things
- * acting like user mode such as get_user_pages.
- */
-#define FIXADDR_USER_START (__fix_to_virt(FIX_VSYSCALL))
-#define FIXADDR_USER_END (FIXADDR_USER_START + PAGE_SIZE)
-
-
extern void __this_fixmap_does_not_exist(void);

/*
Index: linux-vdso-rand.q/include/asm-i386/mmu.h
===================================================================
--- linux-vdso-rand.q.orig/include/asm-i386/mmu.h
+++ linux-vdso-rand.q/include/asm-i386/mmu.h
@@ -12,6 +12,7 @@ typedef struct {
int size;
struct semaphore sem;
void *ldt;
+ void *vdso;
} mm_context_t;

#endif
Index: linux-vdso-rand.q/include/asm-i386/page.h
===================================================================
--- linux-vdso-rand.q.orig/include/asm-i386/page.h
+++ linux-vdso-rand.q/include/asm-i386/page.h
@@ -97,6 +97,8 @@ typedef struct { unsigned long pgprot; }

#ifndef __ASSEMBLY__

+struct vm_area_struct;
+
/*
* This much address space is reserved for vmalloc() and iomap()
* as well as fixmap mappings.
@@ -107,6 +109,7 @@ extern int sysctl_legacy_va_layout;

extern int page_is_ram(unsigned long pagenr);

+const char *arch_vma_name(struct vm_area_struct *vma);
#endif /* __ASSEMBLY__ */

#ifdef __ASSEMBLY__
@@ -121,7 +124,7 @@ extern int page_is_ram(unsigned long pag

#define PAGE_OFFSET ((unsigned long)__PAGE_OFFSET)
#define VMALLOC_RESERVE ((unsigned long)__VMALLOC_RESERVE)
-#define MAXMEM (-__PAGE_OFFSET-__VMALLOC_RESERVE)
+#define MAXMEM (__FIXADDR_TOP-__PAGE_OFFSET-__VMALLOC_RESERVE)
#define __pa(x) ((unsigned long)(x)-PAGE_OFFSET)
#define __va(x) ((void *)((unsigned long)(x)+PAGE_OFFSET))
#define pfn_to_kaddr(pfn) __va((pfn) << PAGE_SHIFT)
@@ -137,6 +140,7 @@ extern int page_is_ram(unsigned long pag
((current->personality & READ_IMPLIES_EXEC) ? VM_EXEC : 0 ) | \
VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC)

+#define __HAVE_ARCH_GATE_AREA 1
#endif /* __KERNEL__ */

#include <asm-generic/memory_model.h>
Index: linux-vdso-rand.q/include/asm-i386/thread_info.h
===================================================================
--- linux-vdso-rand.q.orig/include/asm-i386/thread_info.h
+++ linux-vdso-rand.q/include/asm-i386/thread_info.h
@@ -38,6 +38,7 @@ struct thread_info {
0-0xBFFFFFFF for user-thead
0-0xFFFFFFFF for kernel-thread
*/
+ void *sysenter_return;
struct restart_block restart_block;

unsigned long previous_esp; /* ESP of the previous stack in case
Index: linux-vdso-rand.q/include/linux/sched.h
===================================================================
--- linux-vdso-rand.q.orig/include/linux/sched.h
+++ linux-vdso-rand.q/include/linux/sched.h
@@ -40,6 +40,7 @@
#include <linux/auxvec.h> /* For AT_VECTOR_SIZE */

struct exec_domain;
+extern int print_fatal_signals;

/*
* cloning flags:
Index: linux-vdso-rand.q/include/linux/sysctl.h
===================================================================
--- linux-vdso-rand.q.orig/include/linux/sysctl.h
+++ linux-vdso-rand.q/include/linux/sysctl.h
@@ -187,6 +187,7 @@ enum
VM_PERCPU_PAGELIST_FRACTION=30,/* int: fraction of pages in each percpu_pagelist */
VM_ZONE_RECLAIM_MODE=31, /* reclaim local zone memory before going off node */
VM_ZONE_RECLAIM_INTERVAL=32, /* time period to wait after reclaim failure */
+ VM_VDSO_ENABLED=33, /* map VDSO into new processes? */
};


Index: linux-vdso-rand.q/kernel/sysctl.c
===================================================================
--- linux-vdso-rand.q.orig/kernel/sysctl.c
+++ linux-vdso-rand.q/kernel/sysctl.c
@@ -72,7 +72,6 @@ extern int printk_ratelimit_burst;
extern int pid_max_min, pid_max_max;
extern int sysctl_drop_caches;
extern int percpu_pagelist_fraction;
-extern int print_fatal_signals;

#if defined(CONFIG_X86_LOCAL_APIC) && defined(CONFIG_X86)
int unknown_nmi_panic;
@@ -924,6 +923,18 @@ static ctl_table vm_table[] = {
.strategy = &sysctl_jiffies,
},
#endif
+#ifdef CONFIG_X86_32
+ {
+ .ctl_name = VM_VDSO_ENABLED,
+ .procname = "vdso_enabled",
+ .data = &vdso_enabled,
+ .maxlen = sizeof(vdso_enabled),
+ .mode = 0644,
+ .proc_handler = &proc_dointvec,
+ .strategy = &sysctl_intvec,
+ .extra1 = &zero,
+ },
+#endif
{ .ctl_name = 0 }
};

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/