Merge branch 'x86-kaslr-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull perparatory x86 kasrl changes from Ingo Molnar:
 "This contains changes from the ongoing KASLR work, by Kees Cook.

  The main changes are the use of a read-only IDT on x86 (which
  decouples the userspace visible virtual IDT address from the physical
  address), and a rework of ELF relocation support, in preparation of
  random, boot-time kernel image relocation."

* 'x86-kaslr-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86, relocs: Refactor the relocs tool to merge 32- and 64-bit ELF
  x86, relocs: Build separate 32/64-bit tools
  x86, relocs: Add 64-bit ELF support to relocs tool
  x86, relocs: Consolidate processing logic
  x86, relocs: Generalize ELF structure names
  x86: Use a read-only IDT alias on all CPUs
This commit is contained in:
Linus Torvalds 2013-04-30 08:37:24 -07:00
commit 01c7cd0ef5
10 changed files with 661 additions and 306 deletions

View File

@ -104,9 +104,7 @@ enum fixed_addresses {
FIX_LI_PCIA, /* Lithium PCI Bridge A */
FIX_LI_PCIB, /* Lithium PCI Bridge B */
#endif
#ifdef CONFIG_X86_F00F_BUG
FIX_F00F_IDT, /* Virtual mapping for IDT */
#endif
FIX_RO_IDT, /* Virtual mapping for read-only IDT */
#ifdef CONFIG_X86_CYCLONE_TIMER
FIX_CYCLONE_TIMER, /*cyclone timer register*/
#endif

View File

@ -176,20 +176,6 @@ int __cpuinit ppro_with_ram_bug(void)
return 0;
}
#ifdef CONFIG_X86_F00F_BUG
static void __cpuinit trap_init_f00f_bug(void)
{
__set_fixmap(FIX_F00F_IDT, __pa_symbol(idt_table), PAGE_KERNEL_RO);
/*
* Update the IDT descriptor and reload the IDT so that
* it uses the read-only mapped virtual address.
*/
idt_descr.address = fix_to_virt(FIX_F00F_IDT);
load_idt(&idt_descr);
}
#endif
static void __cpuinit intel_smp_check(struct cpuinfo_x86 *c)
{
/* calling is from identify_secondary_cpu() ? */
@ -218,8 +204,7 @@ static void __cpuinit intel_workarounds(struct cpuinfo_x86 *c)
/*
* All current models of Pentium and Pentium with MMX technology CPUs
* have the F0 0F bug, which lets nonprivileged users lock up the
* system.
* Note that the workaround only should be initialized once...
* system. Announce that the fault handler will be checking for it.
*/
clear_cpu_bug(c, X86_BUG_F00F);
if (!paravirt_enabled() && c->x86 == 5) {
@ -227,7 +212,6 @@ static void __cpuinit intel_workarounds(struct cpuinfo_x86 *c)
set_cpu_bug(c, X86_BUG_F00F);
if (!f00f_workaround_enabled) {
trap_init_f00f_bug();
printk(KERN_NOTICE "Intel Pentium with F0 0F bug - workaround enabled.\n");
f00f_workaround_enabled = 1;
}

View File

@ -56,6 +56,7 @@
#include <asm/i387.h>
#include <asm/fpu-internal.h>
#include <asm/mce.h>
#include <asm/fixmap.h>
#include <asm/mach_traps.h>
#ifdef CONFIG_X86_64
@ -768,6 +769,14 @@ void __init trap_init(void)
set_bit(SYSCALL_VECTOR, used_vectors);
#endif
/*
* Set the IDT descriptor to a fixed read-only location, so that the
* "sidt" instruction will not leak the location of the kernel, and
* to defend the IDT against arbitrary memory write vulnerabilities.
* It will be reloaded in cpu_init() */
__set_fixmap(FIX_RO_IDT, __pa_symbol(idt_table), PAGE_KERNEL_RO);
idt_descr.address = fix_to_virt(FIX_RO_IDT);
/*
* Should be a barrier for any external CPU state:
*/

View File

@ -39,4 +39,5 @@ $(obj)/insn_sanity.o: $(srctree)/arch/x86/lib/insn.c $(srctree)/arch/x86/lib/ina
HOST_EXTRACFLAGS += -I$(srctree)/tools/include
hostprogs-y += relocs
relocs-objs := relocs_32.o relocs_64.o relocs_common.o
relocs: $(obj)/relocs

File diff suppressed because it is too large Load Diff

36
arch/x86/tools/relocs.h Normal file
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@ -0,0 +1,36 @@
#ifndef RELOCS_H
#define RELOCS_H
#include <stdio.h>
#include <stdarg.h>
#include <stdlib.h>
#include <stdint.h>
#include <inttypes.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <elf.h>
#include <byteswap.h>
#define USE_BSD
#include <endian.h>
#include <regex.h>
#include <tools/le_byteshift.h>
void die(char *fmt, ...);
#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
enum symtype {
S_ABS,
S_REL,
S_SEG,
S_LIN,
S_NSYMTYPES
};
void process_32(FILE *fp, int use_real_mode, int as_text,
int show_absolute_syms, int show_absolute_relocs);
void process_64(FILE *fp, int use_real_mode, int as_text,
int show_absolute_syms, int show_absolute_relocs);
#endif /* RELOCS_H */

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@ -0,0 +1,17 @@
#include "relocs.h"
#define ELF_BITS 32
#define ELF_MACHINE EM_386
#define ELF_MACHINE_NAME "i386"
#define SHT_REL_TYPE SHT_REL
#define Elf_Rel ElfW(Rel)
#define ELF_CLASS ELFCLASS32
#define ELF_R_SYM(val) ELF32_R_SYM(val)
#define ELF_R_TYPE(val) ELF32_R_TYPE(val)
#define ELF_ST_TYPE(o) ELF32_ST_TYPE(o)
#define ELF_ST_BIND(o) ELF32_ST_BIND(o)
#define ELF_ST_VISIBILITY(o) ELF32_ST_VISIBILITY(o)
#include "relocs.c"

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@ -0,0 +1,17 @@
#include "relocs.h"
#define ELF_BITS 64
#define ELF_MACHINE EM_X86_64
#define ELF_MACHINE_NAME "x86_64"
#define SHT_REL_TYPE SHT_RELA
#define Elf_Rel Elf64_Rela
#define ELF_CLASS ELFCLASS64
#define ELF_R_SYM(val) ELF64_R_SYM(val)
#define ELF_R_TYPE(val) ELF64_R_TYPE(val)
#define ELF_ST_TYPE(o) ELF64_ST_TYPE(o)
#define ELF_ST_BIND(o) ELF64_ST_BIND(o)
#define ELF_ST_VISIBILITY(o) ELF64_ST_VISIBILITY(o)
#include "relocs.c"

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@ -0,0 +1,76 @@
#include "relocs.h"
void die(char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
vfprintf(stderr, fmt, ap);
va_end(ap);
exit(1);
}
static void usage(void)
{
die("relocs [--abs-syms|--abs-relocs|--text|--realmode] vmlinux\n");
}
int main(int argc, char **argv)
{
int show_absolute_syms, show_absolute_relocs;
int as_text, use_real_mode;
const char *fname;
FILE *fp;
int i;
unsigned char e_ident[EI_NIDENT];
show_absolute_syms = 0;
show_absolute_relocs = 0;
as_text = 0;
use_real_mode = 0;
fname = NULL;
for (i = 1; i < argc; i++) {
char *arg = argv[i];
if (*arg == '-') {
if (strcmp(arg, "--abs-syms") == 0) {
show_absolute_syms = 1;
continue;
}
if (strcmp(arg, "--abs-relocs") == 0) {
show_absolute_relocs = 1;
continue;
}
if (strcmp(arg, "--text") == 0) {
as_text = 1;
continue;
}
if (strcmp(arg, "--realmode") == 0) {
use_real_mode = 1;
continue;
}
}
else if (!fname) {
fname = arg;
continue;
}
usage();
}
if (!fname) {
usage();
}
fp = fopen(fname, "r");
if (!fp) {
die("Cannot open %s: %s\n", fname, strerror(errno));
}
if (fread(&e_ident, 1, EI_NIDENT, fp) != EI_NIDENT) {
die("Cannot read %s: %s", fname, strerror(errno));
}
rewind(fp);
if (e_ident[EI_CLASS] == ELFCLASS64)
process_64(fp, use_real_mode, as_text,
show_absolute_syms, show_absolute_relocs);
else
process_32(fp, use_real_mode, as_text,
show_absolute_syms, show_absolute_relocs);
fclose(fp);
return 0;
}

View File

@ -2043,9 +2043,7 @@ static void xen_set_fixmap(unsigned idx, phys_addr_t phys, pgprot_t prot)
switch (idx) {
case FIX_BTMAP_END ... FIX_BTMAP_BEGIN:
#ifdef CONFIG_X86_F00F_BUG
case FIX_F00F_IDT:
#endif
case FIX_RO_IDT:
#ifdef CONFIG_X86_32
case FIX_WP_TEST:
case FIX_VDSO: