mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-02 23:46:41 +07:00
52149ba6b0
A user space program can read uninitialised kernel memory by appending to a file from a bad address and then reading the result back. The cause is the copy_from_user function that does not clear the remaining bytes of the kernel buffer after it got a fault on the user space address. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
167 lines
4.5 KiB
C
167 lines
4.5 KiB
C
/*
|
|
* arch/s390/lib/uaccess_mvcos.c
|
|
*
|
|
* Optimized user space space access functions based on mvcos.
|
|
*
|
|
* Copyright (C) IBM Corp. 2006
|
|
* Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
|
|
* Gerald Schaefer (gerald.schaefer@de.ibm.com)
|
|
*/
|
|
|
|
#include <linux/errno.h>
|
|
#include <linux/mm.h>
|
|
#include <asm/uaccess.h>
|
|
#include <asm/futex.h>
|
|
|
|
#ifndef __s390x__
|
|
#define AHI "ahi"
|
|
#define ALR "alr"
|
|
#define CLR "clr"
|
|
#define LHI "lhi"
|
|
#define SLR "slr"
|
|
#else
|
|
#define AHI "aghi"
|
|
#define ALR "algr"
|
|
#define CLR "clgr"
|
|
#define LHI "lghi"
|
|
#define SLR "slgr"
|
|
#endif
|
|
|
|
size_t copy_from_user_mvcos(size_t size, const void __user *ptr, void *x)
|
|
{
|
|
register unsigned long reg0 asm("0") = 0x81UL;
|
|
unsigned long tmp1, tmp2;
|
|
|
|
tmp1 = -4096UL;
|
|
asm volatile(
|
|
"0: .insn ss,0xc80000000000,0(%0,%2),0(%1),0\n"
|
|
" jz 7f\n"
|
|
"1:"ALR" %0,%3\n"
|
|
" "SLR" %1,%3\n"
|
|
" "SLR" %2,%3\n"
|
|
" j 0b\n"
|
|
"2: la %4,4095(%1)\n"/* %4 = ptr + 4095 */
|
|
" nr %4,%3\n" /* %4 = (ptr + 4095) & -4096 */
|
|
" "SLR" %4,%1\n"
|
|
" "CLR" %0,%4\n" /* copy crosses next page boundary? */
|
|
" jnh 4f\n"
|
|
"3: .insn ss,0xc80000000000,0(%4,%2),0(%1),0\n"
|
|
" "SLR" %0,%4\n"
|
|
" "ALR" %2,%4\n"
|
|
"4:"LHI" %4,-1\n"
|
|
" "ALR" %4,%0\n" /* copy remaining size, subtract 1 */
|
|
" bras %3,6f\n" /* memset loop */
|
|
" xc 0(1,%2),0(%2)\n"
|
|
"5: xc 0(256,%2),0(%2)\n"
|
|
" la %2,256(%2)\n"
|
|
"6:"AHI" %4,-256\n"
|
|
" jnm 5b\n"
|
|
" ex %4,0(%3)\n"
|
|
" j 8f\n"
|
|
"7:"SLR" %0,%0\n"
|
|
"8: \n"
|
|
EX_TABLE(0b,2b) EX_TABLE(3b,4b)
|
|
: "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
|
|
: "d" (reg0) : "cc", "memory");
|
|
return size;
|
|
}
|
|
|
|
size_t copy_to_user_mvcos(size_t size, void __user *ptr, const void *x)
|
|
{
|
|
register unsigned long reg0 asm("0") = 0x810000UL;
|
|
unsigned long tmp1, tmp2;
|
|
|
|
tmp1 = -4096UL;
|
|
asm volatile(
|
|
"0: .insn ss,0xc80000000000,0(%0,%1),0(%2),0\n"
|
|
" jz 4f\n"
|
|
"1:"ALR" %0,%3\n"
|
|
" "SLR" %1,%3\n"
|
|
" "SLR" %2,%3\n"
|
|
" j 0b\n"
|
|
"2: la %4,4095(%1)\n"/* %4 = ptr + 4095 */
|
|
" nr %4,%3\n" /* %4 = (ptr + 4095) & -4096 */
|
|
" "SLR" %4,%1\n"
|
|
" "CLR" %0,%4\n" /* copy crosses next page boundary? */
|
|
" jnh 5f\n"
|
|
"3: .insn ss,0xc80000000000,0(%4,%1),0(%2),0\n"
|
|
" "SLR" %0,%4\n"
|
|
" j 5f\n"
|
|
"4:"SLR" %0,%0\n"
|
|
"5: \n"
|
|
EX_TABLE(0b,2b) EX_TABLE(3b,5b)
|
|
: "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
|
|
: "d" (reg0) : "cc", "memory");
|
|
return size;
|
|
}
|
|
|
|
size_t copy_in_user_mvcos(size_t size, void __user *to, const void __user *from)
|
|
{
|
|
register unsigned long reg0 asm("0") = 0x810081UL;
|
|
unsigned long tmp1, tmp2;
|
|
|
|
tmp1 = -4096UL;
|
|
/* FIXME: copy with reduced length. */
|
|
asm volatile(
|
|
"0: .insn ss,0xc80000000000,0(%0,%1),0(%2),0\n"
|
|
" jz 2f\n"
|
|
"1:"ALR" %0,%3\n"
|
|
" "SLR" %1,%3\n"
|
|
" "SLR" %2,%3\n"
|
|
" j 0b\n"
|
|
"2:"SLR" %0,%0\n"
|
|
"3: \n"
|
|
EX_TABLE(0b,3b)
|
|
: "+a" (size), "+a" (to), "+a" (from), "+a" (tmp1), "=a" (tmp2)
|
|
: "d" (reg0) : "cc", "memory");
|
|
return size;
|
|
}
|
|
|
|
size_t clear_user_mvcos(size_t size, void __user *to)
|
|
{
|
|
register unsigned long reg0 asm("0") = 0x810000UL;
|
|
unsigned long tmp1, tmp2;
|
|
|
|
tmp1 = -4096UL;
|
|
asm volatile(
|
|
"0: .insn ss,0xc80000000000,0(%0,%1),0(%4),0\n"
|
|
" jz 4f\n"
|
|
"1:"ALR" %0,%2\n"
|
|
" "SLR" %1,%2\n"
|
|
" j 0b\n"
|
|
"2: la %3,4095(%1)\n"/* %4 = to + 4095 */
|
|
" nr %3,%2\n" /* %4 = (to + 4095) & -4096 */
|
|
" "SLR" %3,%1\n"
|
|
" "CLR" %0,%3\n" /* copy crosses next page boundary? */
|
|
" jnh 5f\n"
|
|
"3: .insn ss,0xc80000000000,0(%3,%1),0(%4),0\n"
|
|
" "SLR" %0,%3\n"
|
|
" j 5f\n"
|
|
"4:"SLR" %0,%0\n"
|
|
"5: \n"
|
|
EX_TABLE(0b,2b) EX_TABLE(3b,5b)
|
|
: "+a" (size), "+a" (to), "+a" (tmp1), "=a" (tmp2)
|
|
: "a" (empty_zero_page), "d" (reg0) : "cc", "memory");
|
|
return size;
|
|
}
|
|
|
|
extern size_t copy_from_user_std_small(size_t, const void __user *, void *);
|
|
extern size_t copy_to_user_std_small(size_t, void __user *, const void *);
|
|
extern size_t strnlen_user_std(size_t, const char __user *);
|
|
extern size_t strncpy_from_user_std(size_t, const char __user *, char *);
|
|
extern int futex_atomic_op(int, int __user *, int, int *);
|
|
extern int futex_atomic_cmpxchg(int __user *, int, int);
|
|
|
|
struct uaccess_ops uaccess_mvcos = {
|
|
.copy_from_user = copy_from_user_mvcos,
|
|
.copy_from_user_small = copy_from_user_std_small,
|
|
.copy_to_user = copy_to_user_mvcos,
|
|
.copy_to_user_small = copy_to_user_std_small,
|
|
.copy_in_user = copy_in_user_mvcos,
|
|
.clear_user = clear_user_mvcos,
|
|
.strnlen_user = strnlen_user_std,
|
|
.strncpy_from_user = strncpy_from_user_std,
|
|
.futex_atomic_op = futex_atomic_op,
|
|
.futex_atomic_cmpxchg = futex_atomic_cmpxchg,
|
|
};
|