Contributors: 10
| Author |
Tokens |
Token Proportion |
Commits |
Commit Proportion |
| Heiko Carstens |
589 |
92.32% |
5 |
23.81% |
| Vasily Gorbik |
16 |
2.51% |
6 |
28.57% |
| Linus Torvalds (pre-git) |
10 |
1.57% |
2 |
9.52% |
| Martin Schwidefsky |
9 |
1.41% |
2 |
9.52% |
| Sven Schnelle |
7 |
1.10% |
1 |
4.76% |
| Linus Torvalds |
2 |
0.31% |
1 |
4.76% |
| Alexander Gordeev |
2 |
0.31% |
1 |
4.76% |
| Paul Gortmaker |
1 |
0.16% |
1 |
4.76% |
| Mike Rapoport |
1 |
0.16% |
1 |
4.76% |
| Greg Kroah-Hartman |
1 |
0.16% |
1 |
4.76% |
| Total |
638 |
|
21 |
|
// SPDX-License-Identifier: GPL-2.0
#ifndef pr_fmt
#define pr_fmt(fmt) "stackprot: " fmt
#endif
#include <linux/export.h>
#include <linux/uaccess.h>
#include <linux/printk.h>
#include <asm/abs_lowcore.h>
#include <asm/sections.h>
#include <asm/machine.h>
#include <asm/asm-offsets.h>
#include <asm/arch-stackprotector.h>
#ifdef __DECOMPRESSOR
#define DEBUGP boot_debug
#define EMERGP boot_emerg
#define PANIC boot_panic
#else /* __DECOMPRESSOR */
#define DEBUGP pr_debug
#define EMERGP pr_emerg
#define PANIC panic
#endif /* __DECOMPRESSOR */
int __bootdata_preserved(stack_protector_debug);
unsigned long __stack_chk_guard;
EXPORT_SYMBOL(__stack_chk_guard);
struct insn_ril {
u8 opc1 : 8;
u8 r1 : 4;
u8 opc2 : 4;
u32 imm;
} __packed;
/*
* Convert a virtual instruction address to a real instruction address. The
* decompressor needs to patch instructions within the kernel image based on
* their virtual addresses, while dynamic address translation is still
* disabled. Therefore a translation from virtual kernel image addresses to
* the corresponding physical addresses is required.
*
* After dynamic address translation is enabled and when the kernel needs to
* patch instructions such a translation is not required since the addresses
* are identical.
*/
static struct insn_ril *vaddress_to_insn(unsigned long vaddress)
{
#ifdef __DECOMPRESSOR
return (struct insn_ril *)__kernel_pa(vaddress);
#else
return (struct insn_ril *)vaddress;
#endif
}
static unsigned long insn_to_vaddress(struct insn_ril *insn)
{
#ifdef __DECOMPRESSOR
return (unsigned long)__kernel_va(insn);
#else
return (unsigned long)insn;
#endif
}
#define INSN_RIL_STRING_SIZE (sizeof(struct insn_ril) * 2 + 1)
static void insn_ril_to_string(char *str, struct insn_ril *insn)
{
u8 *ptr = (u8 *)insn;
int i;
for (i = 0; i < sizeof(*insn); i++)
hex_byte_pack(&str[2 * i], ptr[i]);
str[2 * i] = 0;
}
static void stack_protector_dump(struct insn_ril *old, struct insn_ril *new)
{
char ostr[INSN_RIL_STRING_SIZE];
char nstr[INSN_RIL_STRING_SIZE];
insn_ril_to_string(ostr, old);
insn_ril_to_string(nstr, new);
DEBUGP("%016lx: %s -> %s\n", insn_to_vaddress(old), ostr, nstr);
}
static int stack_protector_verify(struct insn_ril *insn, unsigned long kernel_start)
{
char istr[INSN_RIL_STRING_SIZE];
unsigned long vaddress, offset;
/* larl */
if (insn->opc1 == 0xc0 && insn->opc2 == 0x0)
return 0;
/* lgrl */
if (insn->opc1 == 0xc4 && insn->opc2 == 0x8)
return 0;
insn_ril_to_string(istr, insn);
vaddress = insn_to_vaddress(insn);
if (__is_defined(__DECOMPRESSOR)) {
offset = (unsigned long)insn - kernel_start + TEXT_OFFSET;
EMERGP("Unexpected instruction at %016lx/%016lx: %s\n", vaddress, offset, istr);
PANIC("Stackprotector error\n");
} else {
EMERGP("Unexpected instruction at %016lx: %s\n", vaddress, istr);
}
return -EINVAL;
}
int __stack_protector_apply(unsigned long *start, unsigned long *end, unsigned long kernel_start)
{
unsigned long canary, *loc;
struct insn_ril *insn, new;
int rc;
/*
* Convert LARL/LGRL instructions to LLILF so register R1 contains the
* address of the per-cpu / per-process stack canary:
*
* LARL/LGRL R1,__stack_chk_guard => LLILF R1,__lc_stack_canary
*/
canary = __LC_STACK_CANARY;
if (machine_has_relocated_lowcore())
canary += LOWCORE_ALT_ADDRESS;
for (loc = start; loc < end; loc++) {
insn = vaddress_to_insn(*loc);
rc = stack_protector_verify(insn, kernel_start);
if (rc)
return rc;
new = *insn;
new.opc1 = 0xc0;
new.opc2 = 0xf;
new.imm = canary;
if (stack_protector_debug)
stack_protector_dump(insn, &new);
s390_kernel_write(insn, &new, sizeof(*insn));
}
return 0;
}
#ifdef __DECOMPRESSOR
void __stack_protector_apply_early(unsigned long kernel_start)
{
unsigned long *start, *end;
start = (unsigned long *)vmlinux.stack_prot_start;
end = (unsigned long *)vmlinux.stack_prot_end;
__stack_protector_apply(start, end, kernel_start);
}
#endif