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uma: Add KASAN state transitions

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- Add a UMA_ZONE_NOKASAN flag to indicate that items from a particular
  zone should not be sanitized.  This is applied implicitly for NOFREE
  and cache zones.
- Add KASAN call backs which get invoked:
  1) when a slab is imported into a keg
  2) when an item is allocated from a zone
  3) when an item is freed to a zone
  4) when a slab is freed back to the VM

  In state transitions 1 and 3, memory is poisoned so that accesses will
  trigger a panic.  In state transitions 2 and 4, memory is marked
  valid.
- Disable trashing if KASAN is enabled.  It just adds extra CPU overhead
  to catch problems that are detected by KASAN.

MFC after:	2 weeks
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D29456
This commit is contained in:
Mark Johnston 2021-04-13 17:39:50 -04:00
parent f115c06121
commit 09c8cb717d
2 changed files with 144 additions and 21 deletions
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7
sys/vm/uma.h
View File

@ -276,6 +276,11 @@ uma_zone_t uma_zcache_create(const char *name, int size, uma_ctor ctor,
*
* See sys/smr.h for more details.
*/
#define UMA_ZONE_NOKASAN 0x80000 /*
* Disable KASAN verification. This is
* implied by NOFREE. Cache zones are
* not verified by default.
*/
/* In use by UMA_ZFLAGs: 0xffe00000 */
/*
@ -286,7 +291,7 @@ uma_zone_t uma_zcache_create(const char *name, int size, uma_ctor ctor,
#define UMA_ZONE_INHERIT \
(UMA_ZONE_NOTOUCH | UMA_ZONE_MALLOC | UMA_ZONE_NOFREE | \
UMA_ZONE_VM | UMA_ZONE_NOTPAGE | UMA_ZONE_PCPU | \
UMA_ZONE_FIRSTTOUCH | UMA_ZONE_ROUNDROBIN)
UMA_ZONE_FIRSTTOUCH | UMA_ZONE_ROUNDROBIN | UMA_ZONE_NOKASAN)
/* Definitions for align */
#define UMA_ALIGN_PTR (sizeof(void *) - 1) /* Alignment fit for ptr */

158
sys/vm/uma_core.c
View File

@ -58,6 +58,7 @@ __FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/asan.h>
#include <sys/bitset.h>
#include <sys/domainset.h>
#include <sys/eventhandler.h>
@ -318,6 +319,7 @@ static void bucket_zone_drain(void);
static uma_bucket_t zone_alloc_bucket(uma_zone_t, void *, int, int);
static void *slab_alloc_item(uma_keg_t keg, uma_slab_t slab);
static void slab_free_item(uma_zone_t zone, uma_slab_t slab, void *item);
static size_t slab_sizeof(int nitems);
static uma_keg_t uma_kcreate(uma_zone_t zone, size_t size, uma_init uminit,
uma_fini fini, int align, uint32_t flags);
static int zone_import(void *, void **, int, int, int);
@ -531,6 +533,94 @@ bucket_zone_drain(void)
uma_zone_reclaim(ubz->ubz_zone, UMA_RECLAIM_DRAIN);
}
#ifdef KASAN
static void
kasan_mark_item_valid(uma_zone_t zone, void *item)
{
void *pcpu_item;
size_t sz, rsz;
int i;
if ((zone->uz_flags & UMA_ZONE_NOKASAN) != 0)
return;
sz = zone->uz_size;
rsz = roundup2(sz, KASAN_SHADOW_SCALE);
if ((zone->uz_flags & UMA_ZONE_PCPU) == 0) {
kasan_mark(item, sz, rsz, 0);
} else {
pcpu_item = zpcpu_base_to_offset(item);
for (i = 0; i <= mp_maxid; i++)
kasan_mark(zpcpu_get_cpu(pcpu_item, i), sz, rsz, 0);
}
}
static void
kasan_mark_item_invalid(uma_zone_t zone, void *item)
{
void *pcpu_item;
size_t sz;
int i;
if ((zone->uz_flags & UMA_ZONE_NOKASAN) != 0)
return;
sz = roundup2(zone->uz_size, KASAN_SHADOW_SCALE);
if ((zone->uz_flags & UMA_ZONE_PCPU) == 0) {
kasan_mark(item, 0, sz, KASAN_UMA_FREED);
} else {
pcpu_item = zpcpu_base_to_offset(item);
for (i = 0; i <= mp_maxid; i++)
kasan_mark(zpcpu_get_cpu(pcpu_item, i), 0, sz, 0);
}
}
static void
kasan_mark_slab_valid(uma_keg_t keg, void *mem)
{
size_t sz;
if ((keg->uk_flags & UMA_ZONE_NOKASAN) == 0) {
sz = keg->uk_ppera * PAGE_SIZE;
kasan_mark(mem, sz, sz, 0);
}
}
static void
kasan_mark_slab_invalid(uma_keg_t keg, void *mem)
{
size_t sz;
if ((keg->uk_flags & UMA_ZONE_NOKASAN) == 0) {
if ((keg->uk_flags & UMA_ZFLAG_OFFPAGE) != 0)
sz = keg->uk_ppera * PAGE_SIZE;
else
sz = keg->uk_pgoff;
kasan_mark(mem, 0, sz, KASAN_UMA_FREED);
}
}
#else /* !KASAN */
static void
kasan_mark_item_valid(uma_zone_t zone __unused, void *item __unused)
{
}
static void
kasan_mark_item_invalid(uma_zone_t zone __unused, void *item __unused)
{
}
static void
kasan_mark_slab_valid(uma_keg_t keg __unused, void *mem __unused)
{
}
static void
kasan_mark_slab_invalid(uma_keg_t keg __unused, void *mem __unused)
{
}
#endif /* KASAN */
/*
* Acquire the domain lock and record contention.
*/
@ -1156,8 +1246,11 @@ bucket_drain(uma_zone_t zone, uma_bucket_t bucket)
zone->uz_size, NULL, SKIP_NONE);
}
if (zone->uz_fini)
for (i = 0; i < bucket->ub_cnt; i++)
for (i = 0; i < bucket->ub_cnt; i++) {
kasan_mark_item_valid(zone, bucket->ub_bucket[i]);
zone->uz_fini(bucket->ub_bucket[i], zone->uz_size);
kasan_mark_item_invalid(zone, bucket->ub_bucket[i]);
}
zone->uz_release(zone->uz_arg, bucket->ub_bucket, bucket->ub_cnt);
if (zone->uz_max_items > 0)
zone_free_limit(zone, bucket->ub_cnt);
@ -1362,6 +1455,7 @@ static void
keg_free_slab(uma_keg_t keg, uma_slab_t slab, int start)
{
uint8_t *mem;
size_t size;
int i;
uint8_t flags;
@ -1369,10 +1463,11 @@ keg_free_slab(uma_keg_t keg, uma_slab_t slab, int start)
keg->uk_name, keg, slab, PAGE_SIZE * keg->uk_ppera);
mem = slab_data(slab, keg);
flags = slab->us_flags;
i = start;
size = PAGE_SIZE * keg->uk_ppera;
kasan_mark_slab_valid(keg, mem);
if (keg->uk_fini != NULL) {
for (i--; i > -1; i--)
for (i = start - 1; i > -1; i--)
#ifdef INVARIANTS
/*
* trash_fini implies that dtor was trash_dtor. trash_fini
@ -1387,11 +1482,13 @@ keg_free_slab(uma_keg_t keg, uma_slab_t slab, int start)
#endif
keg->uk_fini(slab_item(slab, keg, i), keg->uk_size);
}
if (keg->uk_flags & UMA_ZFLAG_OFFPAGE)
flags = slab->us_flags;
if (keg->uk_flags & UMA_ZFLAG_OFFPAGE) {
zone_free_item(slabzone(keg->uk_ipers), slab_tohashslab(slab),
NULL, SKIP_NONE);
keg->uk_freef(mem, PAGE_SIZE * keg->uk_ppera, flags);
uma_total_dec(PAGE_SIZE * keg->uk_ppera);
}
keg->uk_freef(mem, size, flags);
uma_total_dec(size);
}
static void
@ -1535,7 +1632,6 @@ keg_alloc_slab(uma_keg_t keg, uma_zone_t zone, int domain, int flags,
int aflags)
{
uma_domain_t dom;
uma_alloc allocf;
uma_slab_t slab;
unsigned long size;
uint8_t *mem;
@ -1545,7 +1641,6 @@ keg_alloc_slab(uma_keg_t keg, uma_zone_t zone, int domain, int flags,
KASSERT(domain >= 0 && domain < vm_ndomains,
("keg_alloc_slab: domain %d out of range", domain));
allocf = keg->uk_allocf;
slab = NULL;
mem = NULL;
if (keg->uk_flags & UMA_ZFLAG_OFFPAGE) {
@ -1574,7 +1669,7 @@ keg_alloc_slab(uma_keg_t keg, uma_zone_t zone, int domain, int flags,
/* zone is passed for legacy reasons. */
size = keg->uk_ppera * PAGE_SIZE;
mem = allocf(zone, size, domain, &sflags, aflags);
mem = keg->uk_allocf(zone, size, domain, &sflags, aflags);
if (mem == NULL) {
if (keg->uk_flags & UMA_ZFLAG_OFFPAGE)
zone_free_item(slabzone(keg->uk_ipers),
@ -1589,7 +1684,7 @@ keg_alloc_slab(uma_keg_t keg, uma_zone_t zone, int domain, int flags,
/* Point the slab into the allocated memory */
if (!(keg->uk_flags & UMA_ZFLAG_OFFPAGE))
slab = (uma_slab_t )(mem + keg->uk_pgoff);
slab = (uma_slab_t)(mem + keg->uk_pgoff);
else
slab_tohashslab(slab)->uhs_data = mem;
@ -1617,6 +1712,7 @@ keg_alloc_slab(uma_keg_t keg, uma_zone_t zone, int domain, int flags,
goto fail;
}
}
kasan_mark_slab_invalid(keg, mem);
KEG_LOCK(keg, domain);
CTR3(KTR_UMA, "keg_alloc_slab: allocated slab %p for %s(%p)",
@ -2604,9 +2700,12 @@ zone_ctor(void *mem, int size, void *udata, int flags)
STAILQ_INIT(&zdom->uzd_buckets);
}
#ifdef INVARIANTS
#if defined(INVARIANTS) && !defined(KASAN)
if (arg->uminit == trash_init && arg->fini == trash_fini)
zone->uz_flags |= UMA_ZFLAG_TRASH | UMA_ZFLAG_CTORDTOR;
#elif defined(KASAN)
if ((arg->flags & (UMA_ZONE_NOFREE | UMA_ZFLAG_CACHE)) != 0)
arg->flags |= UMA_ZONE_NOKASAN;
#endif
/*
@ -3029,7 +3128,7 @@ uma_zcreate(const char *name, size_t size, uma_ctor ctor, uma_dtor dtor,
args.dtor = dtor;
args.uminit = uminit;
args.fini = fini;
#ifdef INVARIANTS
#if defined(INVARIANTS) && !defined(KASAN)
/*
* Inject procedures which check for memory use after free if we are
* allowed to scramble the memory while it is not allocated. This
@ -3186,12 +3285,17 @@ item_ctor(uma_zone_t zone, int uz_flags, int size, void *udata, int flags,
{
#ifdef INVARIANTS
bool skipdbg;
#endif
kasan_mark_item_valid(zone, item);
#ifdef INVARIANTS
skipdbg = uma_dbg_zskip(zone, item);
if (!skipdbg && (zone->uz_flags & UMA_ZFLAG_TRASH) != 0 &&
if (!skipdbg && (uz_flags & UMA_ZFLAG_TRASH) != 0 &&
zone->uz_ctor != trash_ctor)
trash_ctor(item, size, udata, flags);
#endif
/* Check flags before loading ctor pointer. */
if (__predict_false((uz_flags & UMA_ZFLAG_CTORDTOR) != 0) &&
__predict_false(zone->uz_ctor != NULL) &&
@ -3234,6 +3338,7 @@ item_dtor(uma_zone_t zone, void *item, int size, void *udata,
trash_dtor(item, size, udata);
#endif
}
kasan_mark_item_invalid(zone, item);
}
#ifdef NUMA
@ -3955,7 +4060,7 @@ static uma_bucket_t
zone_alloc_bucket(uma_zone_t zone, void *udata, int domain, int flags)
{
uma_bucket_t bucket;
int maxbucket, cnt;
int error, maxbucket, cnt;
CTR3(KTR_UMA, "zone_alloc_bucket zone %s(%p) domain %d", zone->uz_name,
zone, domain);
@ -3990,10 +4095,15 @@ zone_alloc_bucket(uma_zone_t zone, void *udata, int domain, int flags)
if (bucket->ub_cnt != 0 && zone->uz_init != NULL) {
int i;
for (i = 0; i < bucket->ub_cnt; i++)
if (zone->uz_init(bucket->ub_bucket[i], zone->uz_size,
flags) != 0)
for (i = 0; i < bucket->ub_cnt; i++) {
kasan_mark_item_valid(zone, bucket->ub_bucket[i]);
error = zone->uz_init(bucket->ub_bucket[i],
zone->uz_size, flags);
kasan_mark_item_invalid(zone, bucket->ub_bucket[i]);
if (error != 0)
break;
}
/*
* If we couldn't initialize the whole bucket, put the
* rest back onto the freelist.
@ -4060,7 +4170,12 @@ zone_alloc_item(uma_zone_t zone, void *udata, int domain, int flags)
* to be both zone-init'd as well as zone-ctor'd.
*/
if (zone->uz_init != NULL) {
if (zone->uz_init(item, zone->uz_size, flags) != 0) {
int error;
kasan_mark_item_valid(zone, item);
error = zone->uz_init(item, zone->uz_size, flags);
kasan_mark_item_invalid(zone, item);
if (error != 0) {
zone_free_item(zone, item, udata, SKIP_FINI | SKIP_CNT);
goto fail_cnt;
}
@ -4542,8 +4657,11 @@ zone_free_item(uma_zone_t zone, void *item, void *udata, enum zfreeskip skip)
item_dtor(zone, item, zone->uz_size, udata, skip);
if (skip < SKIP_FINI && zone->uz_fini)
if (skip < SKIP_FINI && zone->uz_fini) {
kasan_mark_item_valid(zone, item);
zone->uz_fini(item, zone->uz_size);
kasan_mark_item_invalid(zone, item);
}
zone->uz_release(zone->uz_arg, &item, 1);