mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-09-27 12:57:53 +00:00
page_poison: play nicely with KASAN
[ Upstream commit 4117992df6
]
KASAN does not play well with the page poisoning (CONFIG_PAGE_POISONING).
It triggers false positives in the allocation path:
BUG: KASAN: use-after-free in memchr_inv+0x2ea/0x330
Read of size 8 at addr ffff88881f800000 by task swapper/0
CPU: 0 PID: 0 Comm: swapper Not tainted 5.0.0-rc1+ #54
Call Trace:
dump_stack+0xe0/0x19a
print_address_description.cold.2+0x9/0x28b
kasan_report.cold.3+0x7a/0xb5
__asan_report_load8_noabort+0x19/0x20
memchr_inv+0x2ea/0x330
kernel_poison_pages+0x103/0x3d5
get_page_from_freelist+0x15e7/0x4d90
because KASAN has not yet unpoisoned the shadow page for allocation
before it checks memchr_inv() but only found a stale poison pattern.
Also, false positives in free path,
BUG: KASAN: slab-out-of-bounds in kernel_poison_pages+0x29e/0x3d5
Write of size 4096 at addr ffff8888112cc000 by task swapper/0/1
CPU: 5 PID: 1 Comm: swapper/0 Not tainted 5.0.0-rc1+ #55
Call Trace:
dump_stack+0xe0/0x19a
print_address_description.cold.2+0x9/0x28b
kasan_report.cold.3+0x7a/0xb5
check_memory_region+0x22d/0x250
memset+0x28/0x40
kernel_poison_pages+0x29e/0x3d5
__free_pages_ok+0x75f/0x13e0
due to KASAN adds poisoned redzones around slab objects, but the page
poisoning needs to poison the whole page.
Link: http://lkml.kernel.org/r/20190114233405.67843-1-cai@lca.pw
Signed-off-by: Qian Cai <cai@lca.pw>
Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
parent
31f1a862e0
commit
d49efeb18f
2 changed files with 5 additions and 1 deletions
|
@ -1764,8 +1764,8 @@ inline void post_alloc_hook(struct page *page, unsigned int order,
|
|||
|
||||
arch_alloc_page(page, order);
|
||||
kernel_map_pages(page, 1 << order, 1);
|
||||
kernel_poison_pages(page, 1 << order, 1);
|
||||
kasan_alloc_pages(page, order);
|
||||
kernel_poison_pages(page, 1 << order, 1);
|
||||
set_page_owner(page, order, gfp_flags);
|
||||
}
|
||||
|
||||
|
|
|
@ -6,6 +6,7 @@
|
|||
#include <linux/page_ext.h>
|
||||
#include <linux/poison.h>
|
||||
#include <linux/ratelimit.h>
|
||||
#include <linux/kasan.h>
|
||||
|
||||
static bool want_page_poisoning __read_mostly;
|
||||
|
||||
|
@ -34,7 +35,10 @@ static void poison_page(struct page *page)
|
|||
{
|
||||
void *addr = kmap_atomic(page);
|
||||
|
||||
/* KASAN still think the page is in-use, so skip it. */
|
||||
kasan_disable_current();
|
||||
memset(addr, PAGE_POISON, PAGE_SIZE);
|
||||
kasan_enable_current();
|
||||
kunmap_atomic(addr);
|
||||
}
|
||||
|
||||
|
|
Loading…
Reference in a new issue