From: Igor Stoppa <igor.stoppa@gmail.com>
To: unlisted-recipients:; (no To-header on input)
Cc: Igor Stoppa <igor.stoppa@huawei.com>,
Andy Lutomirski <luto@amacapital.net>,
Nadav Amit <nadav.amit@gmail.com>,
Matthew Wilcox <willy@infradead.org>,
Peter Zijlstra <peterz@infradead.org>,
Kees Cook <keescook@chromium.org>,
Dave Hansen <dave.hansen@linux.intel.com>,
Mimi Zohar <zohar@linux.vnet.ibm.com>,
Thiago Jung Bauermann <bauerman@linux.ibm.com>,
Ahmed Soliman <ahmedsoliman@mena.vt.edu>,
linux-integrity@vger.kernel.org,
kernel-hardening@lists.openwall.com, linux-mm@kvack.org,
linux-kernel@vger.kernel.org
Subject: [RFC PATCH v4 08/12] __wr_after_init: lkdtm test
Date: Tue, 12 Feb 2019 01:27:45 +0200 [thread overview]
Message-ID: <8708f8d2c541ce803072acec153f38011b271e90.1549927666.git.igor.stoppa@huawei.com> (raw)
In-Reply-To: <cover.1549927666.git.igor.stoppa@huawei.com>
Verify that trying to modify a variable with the __wr_after_init
attribute will cause a crash.
Signed-off-by: Igor Stoppa <igor.stoppa@huawei.com>
CC: Andy Lutomirski <luto@amacapital.net>
CC: Nadav Amit <nadav.amit@gmail.com>
CC: Matthew Wilcox <willy@infradead.org>
CC: Peter Zijlstra <peterz@infradead.org>
CC: Kees Cook <keescook@chromium.org>
CC: Dave Hansen <dave.hansen@linux.intel.com>
CC: Mimi Zohar <zohar@linux.vnet.ibm.com>
CC: Thiago Jung Bauermann <bauerman@linux.ibm.com>
CC: Ahmed Soliman <ahmedsoliman@mena.vt.edu>
CC: linux-integrity@vger.kernel.org
CC: kernel-hardening@lists.openwall.com
CC: linux-mm@kvack.org
CC: linux-kernel@vger.kernel.org
---
drivers/misc/lkdtm/core.c | 3 +++
drivers/misc/lkdtm/lkdtm.h | 3 +++
drivers/misc/lkdtm/perms.c | 29 +++++++++++++++++++++++++++++
3 files changed, 35 insertions(+)
diff --git a/drivers/misc/lkdtm/core.c b/drivers/misc/lkdtm/core.c
index 2837dc77478e..73c34b17c433 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_PRMEM
+ CRASHTYPE(WRITE_WR_AFTER_INIT),
+#endif
CRASHTYPE(WRITE_KERN),
CRASHTYPE(REFCOUNT_INC_OVERFLOW),
CRASHTYPE(REFCOUNT_ADD_OVERFLOW),
diff --git a/drivers/misc/lkdtm/lkdtm.h b/drivers/misc/lkdtm/lkdtm.h
index 3c6fd327e166..abba2f52ffa6 100644
--- a/drivers/misc/lkdtm/lkdtm.h
+++ b/drivers/misc/lkdtm/lkdtm.h
@@ -38,6 +38,9 @@ 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);
+#ifdef CONFIG_PRMEM
+void lkdtm_WRITE_WR_AFTER_INIT(void);
+#endif
void lkdtm_WRITE_KERN(void);
void lkdtm_EXEC_DATA(void);
void lkdtm_EXEC_STACK(void);
diff --git a/drivers/misc/lkdtm/perms.c b/drivers/misc/lkdtm/perms.c
index 53b85c9d16b8..f681730aa652 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/prmem.h>
#include <asm/cacheflush.h>
/* Whether or not to fill the target memory area with do_nothing(). */
@@ -27,6 +28,10 @@ static const unsigned long rodata = 0xAA55AA55;
/* This is marked __ro_after_init, so it should ultimately be .rodata. */
static unsigned long ro_after_init __ro_after_init = 0x55AA5500;
+/* This is marked __wr_after_init, so it should be in .rodata. */
+static
+unsigned long wr_after_init __wr_after_init = 0x55AA5500;
+
/*
* This just returns to the caller. It is designed to be copied into
* non-executable memory regions.
@@ -104,6 +109,28 @@ void lkdtm_WRITE_RO_AFTER_INIT(void)
*ptr ^= 0xabcd1234;
}
+#ifdef CONFIG_PRMEM
+
+void lkdtm_WRITE_WR_AFTER_INIT(void)
+{
+ unsigned long *ptr = &wr_after_init;
+
+ /*
+ * Verify we were written to during init. Since an Oops
+ * is considered a "success", a failure is to just skip the
+ * real test.
+ */
+ if ((*ptr & 0xAA) != 0xAA) {
+ pr_info("%p was NOT written during init!?\n", ptr);
+ return;
+ }
+
+ pr_info("attempting bad wr_after_init write at %p\n", ptr);
+ *ptr ^= 0xabcd1234;
+}
+
+#endif
+
void lkdtm_WRITE_KERN(void)
{
size_t size;
@@ -200,4 +227,6 @@ void __init lkdtm_perms_init(void)
/* Make sure we can write to __ro_after_init values during __init */
ro_after_init |= 0xAA;
+ /* Make sure we can write to __wr_after_init during __init */
+ wr_after_init |= 0xAA;
}
--
2.19.1
next prev parent reply other threads:[~2019-02-11 23:29 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-11 23:27 [RFC PATCH v4 00/12] hardening: statically allocated protected memory Igor Stoppa
2019-02-11 23:27 ` [RFC PATCH v4 01/12] __wr_after_init: Core and default arch Igor Stoppa
2019-02-12 2:39 ` Matthew Wilcox
2019-02-12 7:20 ` Igor Stoppa
2019-02-11 23:27 ` [RFC PATCH v4 02/12] __wr_after_init: x86_64: memset_user() Igor Stoppa
2019-02-11 23:27 ` [RFC PATCH v4 03/12] __wr_after_init: x86_64: randomize mapping offset Igor Stoppa
2019-02-11 23:27 ` [RFC PATCH v4 04/12] __wr_after_init: x86_64: enable Igor Stoppa
2019-02-11 23:27 ` [RFC PATCH v4 05/12] __wr_after_init: arm64: memset_user() Igor Stoppa
2019-02-11 23:27 ` [RFC PATCH v4 06/12] __wr_after_init: arm64: enable Igor Stoppa
2019-02-11 23:27 ` [RFC PATCH v4 07/12] __wr_after_init: Documentation: self-protection Igor Stoppa
2019-02-11 23:27 ` Igor Stoppa [this message]
2019-02-11 23:27 ` [RFC PATCH v4 09/12] __wr_after_init: rodata_test: refactor tests Igor Stoppa
2019-02-11 23:27 ` [RFC PATCH v4 10/12] __wr_after_init: rodata_test: test __wr_after_init Igor Stoppa
2019-02-11 23:27 ` [RFC PATCH v4 11/12] __wr_after_init: test write rare functionality Igor Stoppa
2019-02-11 23:27 ` [RFC PATCH v4 12/12] IMA: turn ima_policy_flags into __wr_after_init Igor Stoppa
2019-02-12 0:09 ` [RFC PATCH v4 00/12] hardening: statically allocated protected memory Kees Cook
2019-02-12 0:37 ` Igor Stoppa
2019-02-12 0:46 ` Kees Cook
[not found] ` <CAH2bzCRZ5xYOT0R8piqZx4mSGj1_8fNG=Ce4UU8i6F7mYD9m9Q@mail.gmail.com>
2019-02-12 1:26 ` Kees Cook
2019-02-12 7:09 ` Igor Stoppa
2019-02-12 22:39 ` Kees Cook
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