From: Alexander Popov <alex.popov@linux.com>
To: Kees Cook <keescook@chromium.org>, Jann Horn <jannh@google.com>,
Will Deacon <will@kernel.org>,
Andrey Ryabinin <aryabinin@virtuozzo.com>,
Alexander Potapenko <glider@google.com>,
Dmitry Vyukov <dvyukov@google.com>,
Christoph Lameter <cl@linux.com>,
Pekka Enberg <penberg@kernel.org>,
David Rientjes <rientjes@google.com>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
Andrew Morton <akpm@linux-foundation.org>,
Masahiro Yamada <masahiroy@kernel.org>,
Masami Hiramatsu <mhiramat@kernel.org>,
Steven Rostedt <rostedt@goodmis.org>,
Peter Zijlstra <peterz@infradead.org>,
Krzysztof Kozlowski <krzk@kernel.org>,
Patrick Bellasi <patrick.bellasi@arm.com>,
David Howells <dhowells@redhat.com>,
Eric Biederman <ebiederm@xmission.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Laura Abbott <labbott@redhat.com>, Arnd Bergmann <arnd@arndb.de>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Daniel Micay <danielmicay@gmail.com>,
Andrey Konovalov <andreyknvl@google.com>,
Matthew Wilcox <willy@infradead.org>,
Pavel Machek <pavel@denx.de>,
Valentin Schneider <valentin.schneider@arm.com>,
kasan-dev@googlegroups.com, linux-mm@kvack.org,
kernel-hardening@lists.openwall.com,
linux-kernel@vger.kernel.org,
Alexander Popov <alex.popov@linux.com>
Cc: notify@kernel.org
Subject: [PATCH RFC v2 3/6] mm: Integrate SLAB_QUARANTINE with init_on_free
Date: Tue, 29 Sep 2020 21:35:10 +0300 [thread overview]
Message-ID: <20200929183513.380760-4-alex.popov@linux.com> (raw)
In-Reply-To: <20200929183513.380760-1-alex.popov@linux.com>
Having slab quarantine without memory erasing is harmful.
If the quarantined objects are not cleaned and contain data, then:
1. they will be useful for use-after-free exploitation,
2. there is no chance to detect use-after-free access.
So we want the quarantined objects to be erased.
Enable init_on_free that cleans objects before placing them into
the quarantine. CONFIG_PAGE_POISONING should be disabled since it
cuts off init_on_free.
Signed-off-by: Alexander Popov <alex.popov@linux.com>
---
init/Kconfig | 3 ++-
mm/page_alloc.c | 22 ++++++++++++++++++++++
2 files changed, 24 insertions(+), 1 deletion(-)
diff --git a/init/Kconfig b/init/Kconfig
index 358c8ce818f4..cd4cee71fd4e 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -1933,7 +1933,8 @@ config SLAB_FREELIST_HARDENED
config SLAB_QUARANTINE
bool "Enable slab freelist quarantine"
- depends on !KASAN && (SLAB || SLUB)
+ depends on !KASAN && (SLAB || SLUB) && !PAGE_POISONING
+ select INIT_ON_FREE_DEFAULT_ON
help
Enable slab freelist quarantine to delay reusing of freed slab
objects. If this feature is enabled, freed objects are stored
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index fab5e97dc9ca..f67118e88500 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -168,6 +168,27 @@ static int __init early_init_on_alloc(char *buf)
}
early_param("init_on_alloc", early_init_on_alloc);
+#ifdef CONFIG_SLAB_QUARANTINE
+static int __init early_init_on_free(char *buf)
+{
+ /*
+ * Having slab quarantine without memory erasing is harmful.
+ * If the quarantined objects are not cleaned and contain data, then:
+ * 1. they will be useful for use-after-free exploitation,
+ * 2. use-after-free access may not be detected.
+ * So we want the quarantined objects to be erased.
+ *
+ * Enable init_on_free that cleans objects before placing them into
+ * the quarantine. CONFIG_PAGE_POISONING should be disabled since it
+ * cuts off init_on_free.
+ */
+ BUILD_BUG_ON(!IS_ENABLED(CONFIG_INIT_ON_FREE_DEFAULT_ON));
+ BUILD_BUG_ON(IS_ENABLED(CONFIG_PAGE_POISONING));
+ pr_info("mem auto-init: init_on_free is on for CONFIG_SLAB_QUARANTINE\n");
+
+ return 0;
+}
+#else /* CONFIG_SLAB_QUARANTINE */
static int __init early_init_on_free(char *buf)
{
int ret;
@@ -184,6 +205,7 @@ static int __init early_init_on_free(char *buf)
static_branch_disable(&init_on_free);
return ret;
}
+#endif /* CONFIG_SLAB_QUARANTINE */
early_param("init_on_free", early_init_on_free);
/*
--
2.26.2
next prev parent reply other threads:[~2020-09-29 18:35 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-29 18:35 [PATCH RFC v2 0/6] Break heap spraying needed for exploiting use-after-free Alexander Popov
2020-09-29 18:35 ` [PATCH RFC v2 1/6] mm: Extract SLAB_QUARANTINE from KASAN Alexander Popov
2020-09-29 18:35 ` [PATCH RFC v2 2/6] mm/slab: Perform init_on_free earlier Alexander Popov
2020-09-30 12:50 ` Alexander Potapenko
2020-10-01 19:48 ` Alexander Popov
2020-12-03 19:50 ` Alexander Popov
2020-12-03 20:49 ` Andrew Morton
2020-12-04 11:54 ` Alexander Popov
2020-09-29 18:35 ` Alexander Popov [this message]
2020-09-29 18:35 ` [PATCH RFC v2 4/6] mm: Implement slab quarantine randomization Alexander Popov
2020-09-29 18:35 ` [PATCH RFC v2 5/6] lkdtm: Add heap quarantine tests Alexander Popov
2020-09-29 18:35 ` [PATCH RFC v2 6/6] mm: Add heap quarantine verbose debugging (not for merge) Alexander Popov
2020-10-01 19:42 ` [PATCH RFC v2 0/6] Break heap spraying needed for exploiting use-after-free Alexander Popov
2020-10-05 22:56 ` Jann Horn
2020-10-06 0:44 ` Matthew Wilcox
2020-10-06 0:48 ` Jann Horn
2020-10-06 2:09 ` Kees Cook
2020-10-06 2:16 ` Jann Horn
2020-10-06 2:19 ` Daniel Micay
2020-10-06 8:35 ` Christopher Lameter
2020-10-06 8:32 ` Christopher Lameter
2020-10-06 17:56 ` Alexander Popov
2020-10-06 18:37 ` Jann Horn
2020-10-06 19:25 ` Alexander Popov
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