2005-04-16 22:20:36 +00:00
|
|
|
/*
|
|
|
|
* linux/arch/i386/kernel/sysenter.c
|
|
|
|
*
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|
|
|
* (C) Copyright 2002 Linus Torvalds
|
[PATCH] vdso: randomize the i386 vDSO by moving it into a vma
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.
[akpm@osdl.org: cleanups]
[akpm@osdl.org: compile fix]
[akpm@osdl.org: compile fix 2]
[akpm@osdl.org: compile fix 3]
[akpm@osdl.org: revernt MAXMEM change]
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arjan van de Ven <arjan@infradead.org>
Cc: Gerd Hoffmann <kraxel@suse.de>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Zachary Amsden <zach@vmware.com>
Cc: Andi Kleen <ak@muc.de>
Cc: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-27 09:53:50 +00:00
|
|
|
* Portions based on the vdso-randomization code from exec-shield:
|
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|
|
* Copyright(C) 2005-2006, Red Hat, Inc., Ingo Molnar
|
2005-04-16 22:20:36 +00:00
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|
*
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|
* This file contains the needed initializations to support sysenter.
|
|
|
|
*/
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|
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|
#include <linux/init.h>
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|
|
#include <linux/smp.h>
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|
|
#include <linux/thread_info.h>
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|
|
|
#include <linux/sched.h>
|
|
|
|
#include <linux/gfp.h>
|
|
|
|
#include <linux/string.h>
|
|
|
|
#include <linux/elf.h>
|
[PATCH] vdso: randomize the i386 vDSO by moving it into a vma
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.
[akpm@osdl.org: cleanups]
[akpm@osdl.org: compile fix]
[akpm@osdl.org: compile fix 2]
[akpm@osdl.org: compile fix 3]
[akpm@osdl.org: revernt MAXMEM change]
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arjan van de Ven <arjan@infradead.org>
Cc: Gerd Hoffmann <kraxel@suse.de>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Zachary Amsden <zach@vmware.com>
Cc: Andi Kleen <ak@muc.de>
Cc: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-27 09:53:50 +00:00
|
|
|
#include <linux/mm.h>
|
|
|
|
#include <linux/module.h>
|
2005-04-16 22:20:36 +00:00
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|
|
|
|
#include <asm/cpufeature.h>
|
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|
#include <asm/msr.h>
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|
#include <asm/pgtable.h>
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|
#include <asm/unistd.h>
|
2007-05-02 17:27:12 +00:00
|
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|
#include <asm/elf.h>
|
2007-05-02 17:27:12 +00:00
|
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|
#include <asm/tlbflush.h>
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|
enum {
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|
VDSO_DISABLED = 0,
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|
|
VDSO_ENABLED = 1,
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|
|
VDSO_COMPAT = 2,
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|
|
|
};
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|
#ifdef CONFIG_COMPAT_VDSO
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|
#define VDSO_DEFAULT VDSO_COMPAT
|
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|
|
#else
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|
|
#define VDSO_DEFAULT VDSO_ENABLED
|
|
|
|
#endif
|
2005-04-16 22:20:36 +00:00
|
|
|
|
[PATCH] vdso: randomize the i386 vDSO by moving it into a vma
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.
[akpm@osdl.org: cleanups]
[akpm@osdl.org: compile fix]
[akpm@osdl.org: compile fix 2]
[akpm@osdl.org: compile fix 3]
[akpm@osdl.org: revernt MAXMEM change]
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arjan van de Ven <arjan@infradead.org>
Cc: Gerd Hoffmann <kraxel@suse.de>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Zachary Amsden <zach@vmware.com>
Cc: Andi Kleen <ak@muc.de>
Cc: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-27 09:53:50 +00:00
|
|
|
/*
|
|
|
|
* Should the kernel map a VDSO page into processes and pass its
|
|
|
|
* address down to glibc upon exec()?
|
|
|
|
*/
|
2007-05-02 17:27:12 +00:00
|
|
|
unsigned int __read_mostly vdso_enabled = VDSO_DEFAULT;
|
[PATCH] vdso: randomize the i386 vDSO by moving it into a vma
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.
[akpm@osdl.org: cleanups]
[akpm@osdl.org: compile fix]
[akpm@osdl.org: compile fix 2]
[akpm@osdl.org: compile fix 3]
[akpm@osdl.org: revernt MAXMEM change]
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arjan van de Ven <arjan@infradead.org>
Cc: Gerd Hoffmann <kraxel@suse.de>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Zachary Amsden <zach@vmware.com>
Cc: Andi Kleen <ak@muc.de>
Cc: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-27 09:53:50 +00:00
|
|
|
|
|
|
|
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);
|
|
|
|
|
2005-04-16 22:20:36 +00:00
|
|
|
extern asmlinkage void sysenter_entry(void);
|
|
|
|
|
2007-05-02 17:27:12 +00:00
|
|
|
static __init void reloc_symtab(Elf32_Ehdr *ehdr,
|
|
|
|
unsigned offset, unsigned size)
|
|
|
|
{
|
|
|
|
Elf32_Sym *sym = (void *)ehdr + offset;
|
|
|
|
unsigned nsym = size / sizeof(*sym);
|
|
|
|
unsigned i;
|
|
|
|
|
|
|
|
for(i = 0; i < nsym; i++, sym++) {
|
|
|
|
if (sym->st_shndx == SHN_UNDEF ||
|
|
|
|
sym->st_shndx == SHN_ABS)
|
|
|
|
continue; /* skip */
|
|
|
|
|
|
|
|
if (sym->st_shndx > SHN_LORESERVE) {
|
|
|
|
printk(KERN_INFO "VDSO: unexpected st_shndx %x\n",
|
|
|
|
sym->st_shndx);
|
|
|
|
continue;
|
|
|
|
}
|
|
|
|
|
|
|
|
switch(ELF_ST_TYPE(sym->st_info)) {
|
|
|
|
case STT_OBJECT:
|
|
|
|
case STT_FUNC:
|
|
|
|
case STT_SECTION:
|
|
|
|
case STT_FILE:
|
|
|
|
sym->st_value += VDSO_HIGH_BASE;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
static __init void reloc_dyn(Elf32_Ehdr *ehdr, unsigned offset)
|
|
|
|
{
|
|
|
|
Elf32_Dyn *dyn = (void *)ehdr + offset;
|
|
|
|
|
|
|
|
for(; dyn->d_tag != DT_NULL; dyn++)
|
|
|
|
switch(dyn->d_tag) {
|
|
|
|
case DT_PLTGOT:
|
|
|
|
case DT_HASH:
|
|
|
|
case DT_STRTAB:
|
|
|
|
case DT_SYMTAB:
|
|
|
|
case DT_RELA:
|
|
|
|
case DT_INIT:
|
|
|
|
case DT_FINI:
|
|
|
|
case DT_REL:
|
|
|
|
case DT_DEBUG:
|
|
|
|
case DT_JMPREL:
|
|
|
|
case DT_VERSYM:
|
|
|
|
case DT_VERDEF:
|
|
|
|
case DT_VERNEED:
|
|
|
|
case DT_ADDRRNGLO ... DT_ADDRRNGHI:
|
|
|
|
/* definitely pointers needing relocation */
|
|
|
|
dyn->d_un.d_ptr += VDSO_HIGH_BASE;
|
|
|
|
break;
|
|
|
|
|
|
|
|
case DT_ENCODING ... OLD_DT_LOOS-1:
|
|
|
|
case DT_LOOS ... DT_HIOS-1:
|
|
|
|
/* Tags above DT_ENCODING are pointers if
|
|
|
|
they're even */
|
|
|
|
if (dyn->d_tag >= DT_ENCODING &&
|
|
|
|
(dyn->d_tag & 1) == 0)
|
|
|
|
dyn->d_un.d_ptr += VDSO_HIGH_BASE;
|
|
|
|
break;
|
|
|
|
|
|
|
|
case DT_VERDEFNUM:
|
|
|
|
case DT_VERNEEDNUM:
|
|
|
|
case DT_FLAGS_1:
|
|
|
|
case DT_RELACOUNT:
|
|
|
|
case DT_RELCOUNT:
|
|
|
|
case DT_VALRNGLO ... DT_VALRNGHI:
|
|
|
|
/* definitely not pointers */
|
|
|
|
break;
|
|
|
|
|
|
|
|
case OLD_DT_LOOS ... DT_LOOS-1:
|
|
|
|
case DT_HIOS ... DT_VALRNGLO-1:
|
|
|
|
default:
|
|
|
|
if (dyn->d_tag > DT_ENCODING)
|
|
|
|
printk(KERN_INFO "VDSO: unexpected DT_tag %x\n",
|
|
|
|
dyn->d_tag);
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
static __init void relocate_vdso(Elf32_Ehdr *ehdr)
|
|
|
|
{
|
|
|
|
Elf32_Phdr *phdr;
|
|
|
|
Elf32_Shdr *shdr;
|
|
|
|
int i;
|
|
|
|
|
|
|
|
BUG_ON(memcmp(ehdr->e_ident, ELFMAG, 4) != 0 ||
|
|
|
|
!elf_check_arch(ehdr) ||
|
|
|
|
ehdr->e_type != ET_DYN);
|
|
|
|
|
|
|
|
ehdr->e_entry += VDSO_HIGH_BASE;
|
|
|
|
|
|
|
|
/* rebase phdrs */
|
|
|
|
phdr = (void *)ehdr + ehdr->e_phoff;
|
|
|
|
for (i = 0; i < ehdr->e_phnum; i++) {
|
|
|
|
phdr[i].p_vaddr += VDSO_HIGH_BASE;
|
|
|
|
|
|
|
|
/* relocate dynamic stuff */
|
|
|
|
if (phdr[i].p_type == PT_DYNAMIC)
|
|
|
|
reloc_dyn(ehdr, phdr[i].p_offset);
|
|
|
|
}
|
|
|
|
|
|
|
|
/* rebase sections */
|
|
|
|
shdr = (void *)ehdr + ehdr->e_shoff;
|
|
|
|
for(i = 0; i < ehdr->e_shnum; i++) {
|
|
|
|
if (!(shdr[i].sh_flags & SHF_ALLOC))
|
|
|
|
continue;
|
|
|
|
|
|
|
|
shdr[i].sh_addr += VDSO_HIGH_BASE;
|
|
|
|
|
|
|
|
if (shdr[i].sh_type == SHT_SYMTAB ||
|
|
|
|
shdr[i].sh_type == SHT_DYNSYM)
|
|
|
|
reloc_symtab(ehdr, shdr[i].sh_offset,
|
|
|
|
shdr[i].sh_size);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
2005-06-25 21:54:53 +00:00
|
|
|
void enable_sep_cpu(void)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
|
|
|
int cpu = get_cpu();
|
|
|
|
struct tss_struct *tss = &per_cpu(init_tss, cpu);
|
|
|
|
|
2005-06-25 21:54:53 +00:00
|
|
|
if (!boot_cpu_has(X86_FEATURE_SEP)) {
|
|
|
|
put_cpu();
|
|
|
|
return;
|
|
|
|
}
|
|
|
|
|
2007-05-02 17:27:13 +00:00
|
|
|
tss->x86_tss.ss1 = __KERNEL_CS;
|
|
|
|
tss->x86_tss.esp1 = sizeof(struct tss_struct) + (unsigned long) tss;
|
2005-04-16 22:20:36 +00:00
|
|
|
wrmsr(MSR_IA32_SYSENTER_CS, __KERNEL_CS, 0);
|
2007-05-02 17:27:13 +00:00
|
|
|
wrmsr(MSR_IA32_SYSENTER_ESP, tss->x86_tss.esp1, 0);
|
2005-04-16 22:20:36 +00:00
|
|
|
wrmsr(MSR_IA32_SYSENTER_EIP, (unsigned long) sysenter_entry, 0);
|
|
|
|
put_cpu();
|
|
|
|
}
|
|
|
|
|
2007-05-02 17:27:12 +00:00
|
|
|
static struct vm_area_struct gate_vma;
|
|
|
|
|
|
|
|
static int __init gate_vma_init(void)
|
|
|
|
{
|
|
|
|
gate_vma.vm_mm = NULL;
|
|
|
|
gate_vma.vm_start = FIXADDR_USER_START;
|
|
|
|
gate_vma.vm_end = FIXADDR_USER_END;
|
|
|
|
gate_vma.vm_flags = VM_READ | VM_MAYREAD | VM_EXEC | VM_MAYEXEC;
|
|
|
|
gate_vma.vm_page_prot = __P101;
|
|
|
|
/*
|
|
|
|
* Make sure the vDSO gets into every core dump.
|
|
|
|
* Dumping its contents makes post-mortem fully interpretable later
|
|
|
|
* without matching up the same kernel and hardware config to see
|
|
|
|
* what PC values meant.
|
|
|
|
*/
|
|
|
|
gate_vma.vm_flags |= VM_ALWAYSDUMP;
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
2005-04-16 22:20:36 +00:00
|
|
|
/*
|
|
|
|
* These symbols are defined by vsyscall.o to mark the bounds
|
|
|
|
* of the ELF DSO images included therein.
|
|
|
|
*/
|
|
|
|
extern const char vsyscall_int80_start, vsyscall_int80_end;
|
|
|
|
extern const char vsyscall_sysenter_start, vsyscall_sysenter_end;
|
2007-02-08 22:20:42 +00:00
|
|
|
static struct page *syscall_pages[1];
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2007-05-02 17:27:12 +00:00
|
|
|
static void map_compat_vdso(int map)
|
|
|
|
{
|
|
|
|
static int vdso_mapped;
|
|
|
|
|
|
|
|
if (map == vdso_mapped)
|
|
|
|
return;
|
|
|
|
|
|
|
|
vdso_mapped = map;
|
|
|
|
|
|
|
|
__set_fixmap(FIX_VDSO, page_to_pfn(syscall_pages[0]) << PAGE_SHIFT,
|
|
|
|
map ? PAGE_READONLY_EXEC : PAGE_NONE);
|
|
|
|
|
|
|
|
/* flush stray tlbs */
|
|
|
|
flush_tlb_all();
|
|
|
|
}
|
|
|
|
|
2007-05-02 17:27:12 +00:00
|
|
|
int __init sysenter_setup(void)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
2007-02-08 22:20:42 +00:00
|
|
|
void *syscall_page = (void *)get_zeroed_page(GFP_ATOMIC);
|
2007-05-02 17:27:12 +00:00
|
|
|
const void *vsyscall;
|
|
|
|
size_t vsyscall_len;
|
|
|
|
|
2007-02-08 22:20:42 +00:00
|
|
|
syscall_pages[0] = virt_to_page(syscall_page);
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2007-05-02 17:27:12 +00:00
|
|
|
gate_vma_init();
|
|
|
|
|
[PATCH] vdso: randomize the i386 vDSO by moving it into a vma
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.
[akpm@osdl.org: cleanups]
[akpm@osdl.org: compile fix]
[akpm@osdl.org: compile fix 2]
[akpm@osdl.org: compile fix 3]
[akpm@osdl.org: revernt MAXMEM change]
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arjan van de Ven <arjan@infradead.org>
Cc: Gerd Hoffmann <kraxel@suse.de>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Zachary Amsden <zach@vmware.com>
Cc: Andi Kleen <ak@muc.de>
Cc: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-27 09:53:50 +00:00
|
|
|
printk("Compat vDSO mapped to %08lx.\n", __fix_to_virt(FIX_VDSO));
|
2005-04-16 22:20:36 +00:00
|
|
|
|
|
|
|
if (!boot_cpu_has(X86_FEATURE_SEP)) {
|
2007-05-02 17:27:12 +00:00
|
|
|
vsyscall = &vsyscall_int80_start;
|
|
|
|
vsyscall_len = &vsyscall_int80_end - &vsyscall_int80_start;
|
|
|
|
} else {
|
|
|
|
vsyscall = &vsyscall_sysenter_start;
|
|
|
|
vsyscall_len = &vsyscall_sysenter_end - &vsyscall_sysenter_start;
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
2007-05-02 17:27:12 +00:00
|
|
|
memcpy(syscall_page, vsyscall, vsyscall_len);
|
|
|
|
relocate_vdso(syscall_page);
|
2005-04-16 22:20:36 +00:00
|
|
|
|
|
|
|
return 0;
|
|
|
|
}
|
[PATCH] vdso: randomize the i386 vDSO by moving it into a vma
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.
[akpm@osdl.org: cleanups]
[akpm@osdl.org: compile fix]
[akpm@osdl.org: compile fix 2]
[akpm@osdl.org: compile fix 3]
[akpm@osdl.org: revernt MAXMEM change]
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arjan van de Ven <arjan@infradead.org>
Cc: Gerd Hoffmann <kraxel@suse.de>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Zachary Amsden <zach@vmware.com>
Cc: Andi Kleen <ak@muc.de>
Cc: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-27 09:53:50 +00:00
|
|
|
|
|
|
|
/* 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 mm_struct *mm = current->mm;
|
|
|
|
unsigned long addr;
|
2007-05-02 17:27:16 +00:00
|
|
|
int ret = 0;
|
2007-05-02 17:27:12 +00:00
|
|
|
bool compat;
|
[PATCH] vdso: randomize the i386 vDSO by moving it into a vma
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.
[akpm@osdl.org: cleanups]
[akpm@osdl.org: compile fix]
[akpm@osdl.org: compile fix 2]
[akpm@osdl.org: compile fix 3]
[akpm@osdl.org: revernt MAXMEM change]
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arjan van de Ven <arjan@infradead.org>
Cc: Gerd Hoffmann <kraxel@suse.de>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Zachary Amsden <zach@vmware.com>
Cc: Andi Kleen <ak@muc.de>
Cc: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-27 09:53:50 +00:00
|
|
|
|
|
|
|
down_write(&mm->mmap_sem);
|
|
|
|
|
2007-05-02 17:27:12 +00:00
|
|
|
/* Test compat mode once here, in case someone
|
|
|
|
changes it via sysctl */
|
|
|
|
compat = (vdso_enabled == VDSO_COMPAT);
|
|
|
|
|
|
|
|
map_compat_vdso(compat);
|
|
|
|
|
|
|
|
if (compat)
|
|
|
|
addr = VDSO_HIGH_BASE;
|
|
|
|
else {
|
|
|
|
addr = get_unmapped_area(NULL, 0, PAGE_SIZE, 0, 0);
|
|
|
|
if (IS_ERR_VALUE(addr)) {
|
|
|
|
ret = addr;
|
|
|
|
goto up_fail;
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* MAYWRITE to allow gdb to COW and set breakpoints
|
|
|
|
*
|
|
|
|
* Make sure the vDSO gets into every core dump.
|
|
|
|
* Dumping its contents makes post-mortem fully
|
|
|
|
* interpretable later without matching up the same
|
|
|
|
* kernel and hardware config to see what PC values
|
|
|
|
* meant.
|
|
|
|
*/
|
|
|
|
ret = install_special_mapping(mm, addr, PAGE_SIZE,
|
|
|
|
VM_READ|VM_EXEC|
|
|
|
|
VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC|
|
|
|
|
VM_ALWAYSDUMP,
|
|
|
|
syscall_pages);
|
|
|
|
|
|
|
|
if (ret)
|
|
|
|
goto up_fail;
|
|
|
|
}
|
[PATCH] vdso: randomize the i386 vDSO by moving it into a vma
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.
[akpm@osdl.org: cleanups]
[akpm@osdl.org: compile fix]
[akpm@osdl.org: compile fix 2]
[akpm@osdl.org: compile fix 3]
[akpm@osdl.org: revernt MAXMEM change]
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arjan van de Ven <arjan@infradead.org>
Cc: Gerd Hoffmann <kraxel@suse.de>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Zachary Amsden <zach@vmware.com>
Cc: Andi Kleen <ak@muc.de>
Cc: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-27 09:53:50 +00:00
|
|
|
|
|
|
|
current->mm->context.vdso = (void *)addr;
|
|
|
|
current_thread_info()->sysenter_return =
|
2007-05-02 17:27:12 +00:00
|
|
|
(void *)VDSO_SYM(&SYSENTER_RETURN);
|
|
|
|
|
|
|
|
up_fail:
|
[PATCH] vdso: randomize the i386 vDSO by moving it into a vma
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.
[akpm@osdl.org: cleanups]
[akpm@osdl.org: compile fix]
[akpm@osdl.org: compile fix 2]
[akpm@osdl.org: compile fix 3]
[akpm@osdl.org: revernt MAXMEM change]
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arjan van de Ven <arjan@infradead.org>
Cc: Gerd Hoffmann <kraxel@suse.de>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Zachary Amsden <zach@vmware.com>
Cc: Andi Kleen <ak@muc.de>
Cc: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-27 09:53:50 +00:00
|
|
|
up_write(&mm->mmap_sem);
|
2007-05-02 17:27:12 +00:00
|
|
|
|
[PATCH] vdso: randomize the i386 vDSO by moving it into a vma
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.
[akpm@osdl.org: cleanups]
[akpm@osdl.org: compile fix]
[akpm@osdl.org: compile fix 2]
[akpm@osdl.org: compile fix 3]
[akpm@osdl.org: revernt MAXMEM change]
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arjan van de Ven <arjan@infradead.org>
Cc: Gerd Hoffmann <kraxel@suse.de>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Zachary Amsden <zach@vmware.com>
Cc: Andi Kleen <ak@muc.de>
Cc: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-27 09:53:50 +00:00
|
|
|
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)
|
|
|
|
{
|
2007-05-02 17:27:12 +00:00
|
|
|
struct mm_struct *mm = tsk->mm;
|
|
|
|
|
|
|
|
/* Check to see if this task was created in compat vdso mode */
|
|
|
|
if (mm && mm->context.vdso == (void *)VDSO_HIGH_BASE)
|
|
|
|
return &gate_vma;
|
[PATCH] vdso: randomize the i386 vDSO by moving it into a vma
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.
[akpm@osdl.org: cleanups]
[akpm@osdl.org: compile fix]
[akpm@osdl.org: compile fix 2]
[akpm@osdl.org: compile fix 3]
[akpm@osdl.org: revernt MAXMEM change]
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arjan van de Ven <arjan@infradead.org>
Cc: Gerd Hoffmann <kraxel@suse.de>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Zachary Amsden <zach@vmware.com>
Cc: Andi Kleen <ak@muc.de>
Cc: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-27 09:53:50 +00:00
|
|
|
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;
|
|
|
|
}
|