From: Kees Cook <keescook@chromium.org>
To: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Kees Cook <keescook@chromium.org>,
Elena Petrova <lenaptr@google.com>,
Alexander Potapenko <glider@google.com>,
Dmitry Vyukov <dvyukov@google.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Dan Carpenter <dan.carpenter@oracle.com>,
"Gustavo A. R. Silva" <gustavo@embeddedor.com>,
Arnd Bergmann <arnd@arndb.de>,
Ard Biesheuvel <ard.biesheuvel@linaro.org>,
Andrew Morton <akpm@linux-foundation.org>,
kasan-dev@googlegroups.com, linux-kernel@vger.kernel.org,
kernel-hardening@lists.openwall.com
Subject: [PATCH 3/3] lkdtm/bugs: Add arithmetic overflow and array bounds checks
Date: Tue, 19 Nov 2019 17:06:36 -0800 [thread overview]
Message-ID: <20191120010636.27368-4-keescook@chromium.org> (raw)
In-Reply-To: <20191120010636.27368-1-keescook@chromium.org>
Adds LKDTM tests for arithmetic overflow (both signed and unsigned),
as well as array bounds checking.
Signed-off-by: Kees Cook <keescook@chromium.org>
---
drivers/misc/lkdtm/bugs.c | 75 ++++++++++++++++++++++++++++++++++++++
drivers/misc/lkdtm/core.c | 3 ++
drivers/misc/lkdtm/lkdtm.h | 3 ++
3 files changed, 81 insertions(+)
diff --git a/drivers/misc/lkdtm/bugs.c b/drivers/misc/lkdtm/bugs.c
index 7284a22b1a09..8b4ef30f53c6 100644
--- a/drivers/misc/lkdtm/bugs.c
+++ b/drivers/misc/lkdtm/bugs.c
@@ -11,6 +11,7 @@
#include <linux/sched/signal.h>
#include <linux/sched/task_stack.h>
#include <linux/uaccess.h>
+#include <linux/slab.h>
struct lkdtm_list {
struct list_head node;
@@ -171,6 +172,80 @@ void lkdtm_HUNG_TASK(void)
schedule();
}
+volatile unsigned int huge = INT_MAX - 2;
+volatile unsigned int ignored;
+
+void lkdtm_OVERFLOW_SIGNED(void)
+{
+ int value;
+
+ value = huge;
+ pr_info("Normal signed addition ...\n");
+ value += 1;
+ ignored = value;
+
+ pr_info("Overflowing signed addition ...\n");
+ value += 4;
+ ignored = value;
+}
+
+
+void lkdtm_OVERFLOW_UNSIGNED(void)
+{
+ unsigned int value;
+
+ value = huge;
+ pr_info("Normal unsigned addition ...\n");
+ value += 1;
+ ignored = value;
+
+ pr_info("Overflowing unsigned addition ...\n");
+ value += 4;
+ ignored = value;
+}
+
+/* Intentially using old-style flex array definition of 1 byte. */
+struct array_bounds_flex_array {
+ int one;
+ int two;
+ char data[1];
+};
+
+struct array_bounds {
+ int one;
+ int two;
+ char data[8];
+ int three;
+};
+
+void lkdtm_ARRAY_BOUNDS(void)
+{
+ struct array_bounds_flex_array *not_checked;
+ struct array_bounds *checked;
+ int i;
+
+ not_checked = kmalloc(sizeof(*not_checked) * 2, GFP_KERNEL);
+ checked = kmalloc(sizeof(*checked) * 2, GFP_KERNEL);
+
+ pr_info("Array access within bounds ...\n");
+ /* For both, touch all bytes in the actual member size. */
+ for (i = 0; i < sizeof(checked->data); i++)
+ checked->data[i] = 'A';
+ /*
+ * For the uninstrumented flex array member, also touch 1 byte
+ * beyond to verify it is correctly uninstrumented.
+ */
+ for (i = 0; i < sizeof(not_checked->data) + 1; i++)
+ not_checked->data[i] = 'A';
+
+ pr_info("Array access beyond bounds ...\n");
+ for (i = 0; i < sizeof(checked->data) + 1; i++)
+ checked->data[i] = 'B';
+
+ kfree(not_checked);
+ kfree(checked);
+}
+
void lkdtm_CORRUPT_LIST_ADD(void)
{
/*
diff --git a/drivers/misc/lkdtm/core.c b/drivers/misc/lkdtm/core.c
index cbc4c9045a99..25879f7b0768 100644
--- a/drivers/misc/lkdtm/core.c
+++ b/drivers/misc/lkdtm/core.c
@@ -129,6 +129,9 @@ static const struct crashtype crashtypes[] = {
CRASHTYPE(HARDLOCKUP),
CRASHTYPE(SPINLOCKUP),
CRASHTYPE(HUNG_TASK),
+ CRASHTYPE(OVERFLOW_SIGNED),
+ CRASHTYPE(OVERFLOW_UNSIGNED),
+ CRASHTYPE(ARRAY_BOUNDS),
CRASHTYPE(EXEC_DATA),
CRASHTYPE(EXEC_STACK),
CRASHTYPE(EXEC_KMALLOC),
diff --git a/drivers/misc/lkdtm/lkdtm.h b/drivers/misc/lkdtm/lkdtm.h
index ab446e0bde97..2cd0c5031eea 100644
--- a/drivers/misc/lkdtm/lkdtm.h
+++ b/drivers/misc/lkdtm/lkdtm.h
@@ -22,6 +22,9 @@ void lkdtm_SOFTLOCKUP(void);
void lkdtm_HARDLOCKUP(void);
void lkdtm_SPINLOCKUP(void);
void lkdtm_HUNG_TASK(void);
+void lkdtm_OVERFLOW_SIGNED(void);
+void lkdtm_OVERFLOW_UNSIGNED(void);
+void lkdtm_ARRAY_BOUNDS(void);
void lkdtm_CORRUPT_LIST_ADD(void);
void lkdtm_CORRUPT_LIST_DEL(void);
void lkdtm_CORRUPT_USER_DS(void);
--
2.17.1
prev parent reply other threads:[~2019-11-20 1:06 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-20 1:06 [PATCH 0/3] ubsan: Split out bounds checker Kees Cook
2019-11-20 1:06 ` [PATCH 1/3] ubsan: Add trap instrumentation option Kees Cook
2019-11-21 12:52 ` Andrey Ryabinin
2019-11-21 17:20 ` Kees Cook
2019-11-21 17:57 ` Kees Cook
2019-11-20 1:06 ` [PATCH 2/3] ubsan: Split "bounds" checker from other options Kees Cook
2019-11-21 12:54 ` Andrey Ryabinin
2019-11-20 1:06 ` Kees Cook [this message]
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=20191120010636.27368-4-keescook@chromium.org \
--to=keescook@chromium.org \
--cc=akpm@linux-foundation.org \
--cc=ard.biesheuvel@linaro.org \
--cc=arnd@arndb.de \
--cc=aryabinin@virtuozzo.com \
--cc=dan.carpenter@oracle.com \
--cc=dvyukov@google.com \
--cc=glider@google.com \
--cc=gustavo@embeddedor.com \
--cc=kasan-dev@googlegroups.com \
--cc=kernel-hardening@lists.openwall.com \
--cc=lenaptr@google.com \
--cc=linux-kernel@vger.kernel.org \
--cc=torvalds@linux-foundation.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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.