From: Igor Stoppa <igor.stoppa@huawei.com>
To: <david@fromorbit.com>, <willy@infradead.org>,
<keescook@chromium.org>, <mhocko@kernel.org>
Cc: <labbott@redhat.com>, <linux-security-module@vger.kernel.org>,
<linux-mm@kvack.org>, <linux-kernel@vger.kernel.org>,
<kernel-hardening@lists.openwall.com>,
Igor Stoppa <igor.stoppa@huawei.com>
Subject: [PATCH 6/7] lkdtm: crash on overwriting protected pmalloc var
Date: Fri, 23 Feb 2018 16:48:06 +0200 [thread overview]
Message-ID: <20180223144807.1180-7-igor.stoppa@huawei.com> (raw)
In-Reply-To: <20180223144807.1180-1-igor.stoppa@huawei.com>
Verify that pmalloc read-only protection is in place: trying to
overwrite a protected variable will crash the kernel.
Signed-off-by: Igor Stoppa <igor.stoppa@huawei.com>
---
drivers/misc/lkdtm.h | 1 +
drivers/misc/lkdtm_core.c | 3 +++
drivers/misc/lkdtm_perms.c | 28 ++++++++++++++++++++++++++++
3 files changed, 32 insertions(+)
diff --git a/drivers/misc/lkdtm.h b/drivers/misc/lkdtm.h
index 9e513dcfd809..dcda3ae76ceb 100644
--- a/drivers/misc/lkdtm.h
+++ b/drivers/misc/lkdtm.h
@@ -38,6 +38,7 @@ void lkdtm_READ_BUDDY_AFTER_FREE(void);
void __init lkdtm_perms_init(void);
void lkdtm_WRITE_RO(void);
void lkdtm_WRITE_RO_AFTER_INIT(void);
+void lkdtm_WRITE_RO_PMALLOC(void);
void lkdtm_WRITE_KERN(void);
void lkdtm_EXEC_DATA(void);
void lkdtm_EXEC_STACK(void);
diff --git a/drivers/misc/lkdtm_core.c b/drivers/misc/lkdtm_core.c
index 2154d1bfd18b..c9fd42bda6ee 100644
--- a/drivers/misc/lkdtm_core.c
+++ b/drivers/misc/lkdtm_core.c
@@ -155,6 +155,9 @@ static const struct crashtype crashtypes[] = {
CRASHTYPE(ACCESS_USERSPACE),
CRASHTYPE(WRITE_RO),
CRASHTYPE(WRITE_RO_AFTER_INIT),
+#ifdef CONFIG_PROTECTABLE_MEMORY
+ CRASHTYPE(WRITE_RO_PMALLOC),
+#endif
CRASHTYPE(WRITE_KERN),
CRASHTYPE(REFCOUNT_INC_OVERFLOW),
CRASHTYPE(REFCOUNT_ADD_OVERFLOW),
diff --git a/drivers/misc/lkdtm_perms.c b/drivers/misc/lkdtm_perms.c
index 53b85c9d16b8..0ac9023fd2b0 100644
--- a/drivers/misc/lkdtm_perms.c
+++ b/drivers/misc/lkdtm_perms.c
@@ -9,6 +9,7 @@
#include <linux/vmalloc.h>
#include <linux/mman.h>
#include <linux/uaccess.h>
+#include <linux/pmalloc.h>
#include <asm/cacheflush.h>
/* Whether or not to fill the target memory area with do_nothing(). */
@@ -104,6 +105,33 @@ void lkdtm_WRITE_RO_AFTER_INIT(void)
*ptr ^= 0xabcd1234;
}
+#ifdef CONFIG_PROTECTABLE_MEMORY
+void lkdtm_WRITE_RO_PMALLOC(void)
+{
+ struct gen_pool *pool;
+ int *i;
+
+ pool = pmalloc_create_pool("pool", 0);
+ if (unlikely(!pool)) {
+ pr_info("Failed preparing pool for pmalloc test.");
+ return;
+ }
+
+ i = (int *)pmalloc(pool, sizeof(int), GFP_KERNEL);
+ if (unlikely(!i)) {
+ pr_info("Failed allocating memory for pmalloc test.");
+ pmalloc_destroy_pool(pool);
+ return;
+ }
+
+ *i = INT_MAX;
+ pmalloc_protect_pool(pool);
+
+ pr_info("attempting bad pmalloc write at %p\n", i);
+ *i = 0;
+}
+#endif
+
void lkdtm_WRITE_KERN(void)
{
size_t size;
--
2.14.1
next prev parent reply other threads:[~2018-02-23 14:48 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-23 14:48 [RFC PATCH v17 0/7] mm: security: ro protection for dynamic data Igor Stoppa
2018-02-23 14:48 ` [PATCH 1/7] genalloc: track beginning of allocations Igor Stoppa
2018-02-23 22:28 ` J Freyensee
2018-02-26 12:09 ` Igor Stoppa
2018-02-26 17:32 ` J Freyensee
2018-02-26 18:44 ` Igor Stoppa
2018-02-25 3:37 ` kbuild test robot
2018-02-23 14:48 ` [PATCH 2/7] genalloc: selftest Igor Stoppa
2018-02-23 22:42 ` J Freyensee
2018-02-26 12:11 ` Igor Stoppa
2018-02-26 17:46 ` J Freyensee
2018-02-26 18:00 ` Igor Stoppa
2018-02-26 19:12 ` Matthew Wilcox
2018-02-26 19:26 ` Igor Stoppa
2018-02-23 14:48 ` [PATCH 3/7] struct page: add field for vm_struct Igor Stoppa
2018-02-25 3:38 ` Matthew Wilcox
2018-02-26 16:37 ` Igor Stoppa
2018-02-23 14:48 ` [PATCH 4/7] Protectable Memory Igor Stoppa
2018-02-24 0:10 ` J Freyensee
2018-02-26 14:28 ` Igor Stoppa
2018-02-26 18:25 ` J Freyensee
2018-02-25 2:33 ` kbuild test robot
2018-02-23 14:48 ` [PATCH 5/7] Pmalloc selftest Igor Stoppa
2018-03-06 16:59 ` J Freyensee
2018-02-23 14:48 ` Igor Stoppa [this message]
2018-02-25 3:46 ` [PATCH 6/7] lkdtm: crash on overwriting protected pmalloc var kbuild test robot
2018-03-06 17:05 ` J Freyensee
2018-03-06 17:08 ` J Freyensee
2018-02-23 14:48 ` [PATCH 7/7] Documentation for Pmalloc Igor Stoppa
2018-02-24 0:26 ` J Freyensee
2018-02-26 15:39 ` Igor Stoppa
2018-02-26 18:32 ` J Freyensee
2018-02-28 20:06 [RFC PATCH v18 0/7] mm: security: ro protection for dynamic data Igor Stoppa
2018-02-28 20:06 ` [PATCH 6/7] lkdtm: crash on overwriting protected pmalloc var Igor Stoppa
2018-03-06 17:20 ` J Freyensee
2018-03-07 13:18 ` Igor Stoppa
2018-03-07 17:26 ` J Freyensee
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