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Change the pattern of KMEM_REDZONE so that the first byte is never '\0'. 

From me and lars@.
This commit is contained in:
maxv 2014-07-03 08:43:49 +00:00
parent a65e94de03
commit 57fd3cffd6
1 changed files with 31 additions and 19 deletions
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50
sys/kern/subr_kmem.c
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@ -1,4 +1,4 @@
/* $NetBSD: subr_kmem.c,v 1.58 2014/07/02 15:00:28 maxv Exp $ */
/* $NetBSD: subr_kmem.c,v 1.59 2014/07/03 08:43:49 maxv Exp $ */
/*-
* Copyright (c) 2009 The NetBSD Foundation, Inc.
@ -90,7 +90,7 @@
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: subr_kmem.c,v 1.58 2014/07/02 15:00:28 maxv Exp $");
__KERNEL_RCSID(0, "$NetBSD: subr_kmem.c,v 1.59 2014/07/03 08:43:49 maxv Exp $");
#include <sys/param.h>
#include <sys/callback.h>
@ -482,16 +482,16 @@ kmem_roundup_size(size_t size)
#else /* defined(_LP64) */
#define PRIME 0x9e3779b1
#endif /* defined(_LP64) */
#endif /* defined(KMEM_POISON) || defined(KMEM_REDZONE) */
#if defined(KMEM_POISON)
static inline uint8_t
kmem_poison_pattern(const void *p)
kmem_pattern_generate(const void *p)
{
return (uint8_t)(((uintptr_t)p) * PRIME
>> ((sizeof(uintptr_t) - sizeof(uint8_t))) * CHAR_BIT);
}
#endif /* defined(KMEM_POISON) || defined(KMEM_REDZONE) */
#if defined(KMEM_POISON)
static int
kmem_poison_ctor(void *arg, void *obj, int flag)
{
@ -511,7 +511,7 @@ kmem_poison_fill(void *p, size_t sz)
cp = p;
ep = cp + sz;
while (cp < ep) {
*cp = kmem_poison_pattern(cp);
*cp = kmem_pattern_generate(cp);
cp++;
}
}
@ -525,7 +525,7 @@ kmem_poison_check(void *p, size_t sz)
cp = p;
ep = cp + sz;
while (cp < ep) {
const uint8_t expected = kmem_poison_pattern(cp);
const uint8_t expected = kmem_pattern_generate(cp);
if (*cp != expected) {
panic("%s: %p: 0x%02x != 0x%02x\n",
@ -562,23 +562,27 @@ kmem_size_check(void *p, size_t sz)
#endif /* defined(KMEM_SIZE) */
#if defined(KMEM_REDZONE)
static inline uint8_t
kmem_redzone_pattern(const void *p)
{
return (uint8_t)(((uintptr_t)p) * PRIME
>> ((sizeof(uintptr_t) - sizeof(uint8_t))) * CHAR_BIT);
}
#define STATIC_BYTE 0xFE
CTASSERT(REDZONE_SIZE > 1);
static void
kmem_redzone_fill(void *p, size_t sz)
{
uint8_t *cp;
uint8_t *cp, pat;
const uint8_t *ep;
cp = (uint8_t *)p + sz;
ep = cp + REDZONE_SIZE;
/*
* We really don't want the first byte of the red zone to be '\0';
* an off-by-one in a string may not be properly detected.
*/
pat = kmem_pattern_generate(cp);
*cp = (pat == '\0') ? STATIC_BYTE: pat;
cp++;
while (cp < ep) {
*cp = kmem_redzone_pattern(cp);
*cp = kmem_pattern_generate(cp);
cp++;
}
}
@ -586,14 +590,22 @@ kmem_redzone_fill(void *p, size_t sz)
static void
kmem_redzone_check(void *p, size_t sz)
{
uint8_t *cp;
uint8_t *cp, pat, expected;
const uint8_t *ep;
cp = (uint8_t *)p + sz;
ep = cp + REDZONE_SIZE;
while (cp < ep) {
const uint8_t expected = kmem_redzone_pattern(cp);
pat = kmem_pattern_generate(cp);
expected = (pat == '\0') ? STATIC_BYTE: pat;
if (expected != *cp) {
panic("%s: %p: 0x%02x != 0x%02x\n",
__func__, cp, *cp, expected);
}
cp++;
while (cp < ep) {
expected = kmem_pattern_generate(cp);
if (*cp != expected) {
panic("%s: %p: 0x%02x != 0x%02x\n",
__func__, cp, *cp, expected);