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authorKees Cook <keescook@chromium.org>2020-04-06 20:12:34 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2020-04-07 10:43:44 -0700
commitae2e1aad3e48e495878d9f149e437a308bfdaefa (patch)
tree51204c710f66a91ce13b44dc400aea830f30e511
parent277a10850f9f4cb3429faf59293e2c89b1a320be (diff)
drivers/misc/lkdtm/bugs.c: add arithmetic overflow and array bounds checks
Adds LKDTM tests for arithmetic overflow (both signed and unsigned), as well as array bounds checking. Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Dmitry Vyukov <dvyukov@google.com> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Konovalov <andreyknvl@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Dan Carpenter <dan.carpenter@oracle.com> Cc: Elena Petrova <lenaptr@google.com> Cc: "Gustavo A. R. Silva" <gustavo@embeddedor.com> Link: http://lkml.kernel.org/r/20200227193516.32566-4-keescook@chromium.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--drivers/misc/lkdtm/bugs.c75
-rw-r--r--drivers/misc/lkdtm/core.c3
-rw-r--r--drivers/misc/lkdtm/lkdtm.h3
3 files changed, 81 insertions, 0 deletions
diff --git a/drivers/misc/lkdtm/bugs.c b/drivers/misc/lkdtm/bugs.c
index cc92bc3ed820..886459e0ddd9 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>
#ifdef CONFIG_X86_32
#include <asm/desc.h>
@@ -175,6 +176,80 @@ 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;
+ volatile 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 5ce4ac8c06fc..a5e344df9166 100644
--- a/drivers/misc/lkdtm/core.c
+++ b/drivers/misc/lkdtm/core.c
@@ -130,6 +130,9 @@ 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 8d13d0176624..601a2156a0d4 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);