From: Igor Stoppa <igor.stoppa@gmail.com>
To: Andy Lutomirski <luto@amacapital.net>,
Kees Cook <keescook@chromium.org>,
Matthew Wilcox <willy@infradead.org>
Cc: igor.stoppa@huawei.com, Nadav Amit <nadav.amit@gmail.com>,
Peter Zijlstra <peterz@infradead.org>,
Dave Hansen <dave.hansen@linux.intel.com>,
linux-integrity@vger.kernel.org,
kernel-hardening@lists.openwall.com, linux-mm@kvack.org,
linux-kernel@vger.kernel.org
Subject: [PATCH 4/6] rodata_test: add verification for __wr_after_init
Date: Tue, 4 Dec 2018 14:18:03 +0200 [thread overview]
Message-ID: <20181204121805.4621-5-igor.stoppa@huawei.com> (raw)
In-Reply-To: <20181204121805.4621-1-igor.stoppa@huawei.com>
The write protection of the __wr_after_init data can be verified with the
same methodology used for const data.
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: linux-integrity@vger.kernel.org
CC: kernel-hardening@lists.openwall.com
CC: linux-mm@kvack.org
CC: linux-kernel@vger.kernel.org
---
mm/rodata_test.c | 17 ++++++++++++++++-
1 file changed, 16 insertions(+), 1 deletion(-)
diff --git a/mm/rodata_test.c b/mm/rodata_test.c
index 3c1e515ca9b1..a98d088ad9cc 100644
--- a/mm/rodata_test.c
+++ b/mm/rodata_test.c
@@ -16,7 +16,19 @@
#define INIT_TEST_VAL 0xC3
+/*
+ * Note: __ro_after_init data is, for every practical effect, equivalent to
+ * const data, since they are even write protected at the same time; there
+ * is no need for separate testing.
+ * __wr_after_init data, otoh, is altered also after the write protection
+ * takes place and it cannot be exploitable for altering more permanent
+ * data.
+ */
+
static const int rodata_test_data = INIT_TEST_VAL;
+static int wr_after_init_test_data __wr_after_init = INIT_TEST_VAL;
+extern long __start_wr_after_init;
+extern long __end_wr_after_init;
static bool test_data(char *data_type, const int *data,
unsigned long start, unsigned long end)
@@ -60,6 +72,9 @@ void rodata_test(void)
{
if (test_data("rodata", &rodata_test_data,
(unsigned long)&__start_rodata,
- (unsigned long)&__end_rodata))
+ (unsigned long)&__end_rodata) &&
+ test_data("wr after init data", &wr_after_init_test_data,
+ (unsigned long)&__start_wr_after_init,
+ (unsigned long)&__end_wr_after_init))
pr_info("all tests were successful\n");
}
--
2.19.1
next prev parent reply other threads:[~2018-12-04 12:18 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-04 12:17 [RFC v1 PATCH 0/6] hardening: statically allocated protected memory Igor Stoppa
2018-12-04 12:18 ` [PATCH 1/6] __wr_after_init: linker section and label Igor Stoppa
2018-12-04 12:18 ` [PATCH 2/6] __wr_after_init: write rare for static allocation Igor Stoppa
2018-12-05 23:13 ` Andy Lutomirski
2018-12-06 9:44 ` Peter Zijlstra
2018-12-09 22:32 ` Igor Stoppa
2018-12-10 9:59 ` Peter Zijlstra
2018-12-09 22:09 ` Igor Stoppa
2018-12-12 9:49 ` Martin Schwidefsky
2018-12-19 22:50 ` Igor Stoppa
2018-12-06 4:44 ` Matthew Wilcox
2018-12-09 22:22 ` Igor Stoppa
2018-12-04 12:18 ` [PATCH 3/6] rodata_test: refactor tests Igor Stoppa
2018-12-04 12:18 ` Igor Stoppa [this message]
2018-12-04 12:18 ` [PATCH 5/6] __wr_after_init: test write rare functionality Igor Stoppa
2018-12-04 12:18 ` [PATCH 6/6] __wr_after_init: lkdtm test Igor Stoppa
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20181204121805.4621-5-igor.stoppa@huawei.com \
--to=igor.stoppa@gmail.com \
--cc=dave.hansen@linux.intel.com \
--cc=igor.stoppa@huawei.com \
--cc=keescook@chromium.org \
--cc=kernel-hardening@lists.openwall.com \
--cc=linux-integrity@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=luto@amacapital.net \
--cc=nadav.amit@gmail.com \
--cc=peterz@infradead.org \
--cc=willy@infradead.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).