Similar to the existing slab overflow and stack exhaustion tests, add
VMALLOC_LINEAR_OVERFLOW (and rename the slab test SLAB_LINEAR_OVERFLOW).
Signed-off-by: Kees Cook <[email protected]>
---
drivers/misc/lkdtm/core.c | 3 ++-
drivers/misc/lkdtm/heap.c | 21 ++++++++++++++++++++-
drivers/misc/lkdtm/lkdtm.h | 3 ++-
tools/testing/selftests/lkdtm/tests.txt | 3 ++-
4 files changed, 26 insertions(+), 4 deletions(-)
diff --git a/drivers/misc/lkdtm/core.c b/drivers/misc/lkdtm/core.c
index b2aff4d87c01..c3a5ad21b3d2 100644
--- a/drivers/misc/lkdtm/core.c
+++ b/drivers/misc/lkdtm/core.c
@@ -119,7 +119,8 @@ static const struct crashtype crashtypes[] = {
CRASHTYPE(UNALIGNED_LOAD_STORE_WRITE),
CRASHTYPE(FORTIFY_OBJECT),
CRASHTYPE(FORTIFY_SUBOBJECT),
- CRASHTYPE(OVERWRITE_ALLOCATION),
+ CRASHTYPE(SLAB_LINEAR_OVERFLOW),
+ CRASHTYPE(VMALLOC_LINEAR_OVERFLOW),
CRASHTYPE(WRITE_AFTER_FREE),
CRASHTYPE(READ_AFTER_FREE),
CRASHTYPE(WRITE_BUDDY_AFTER_FREE),
diff --git a/drivers/misc/lkdtm/heap.c b/drivers/misc/lkdtm/heap.c
index 1323bc16f113..5d491c22e09a 100644
--- a/drivers/misc/lkdtm/heap.c
+++ b/drivers/misc/lkdtm/heap.c
@@ -5,18 +5,37 @@
*/
#include "lkdtm.h"
#include <linux/slab.h>
+#include <linux/vmalloc.h>
#include <linux/sched.h>
static struct kmem_cache *double_free_cache;
static struct kmem_cache *a_cache;
static struct kmem_cache *b_cache;
+/*
+ * If there aren't guard pages, it's likely that a consecutive allocation will
+ * let us overflow into the second allocation without overwriting something real.
+ */
+void lkdtm_VMALLOC_LINEAR_OVERFLOW(void)
+{
+ char *one, *two;
+
+ one = vzalloc(PAGE_SIZE);
+ two = vzalloc(PAGE_SIZE);
+
+ pr_info("Attempting vmalloc linear overflow ...\n");
+ memset(one, 0xAA, PAGE_SIZE + 1);
+
+ vfree(two);
+ vfree(one);
+}
+
/*
* This tries to stay within the next largest power-of-2 kmalloc cache
* to avoid actually overwriting anything important if it's not detected
* correctly.
*/
-void lkdtm_OVERWRITE_ALLOCATION(void)
+void lkdtm_SLAB_LINEAR_OVERFLOW(void)
{
size_t len = 1020;
u32 *data = kmalloc(len, GFP_KERNEL);
diff --git a/drivers/misc/lkdtm/lkdtm.h b/drivers/misc/lkdtm/lkdtm.h
index 5ae48c64df24..5a852d0beee0 100644
--- a/drivers/misc/lkdtm/lkdtm.h
+++ b/drivers/misc/lkdtm/lkdtm.h
@@ -38,7 +38,8 @@ void lkdtm_FORTIFY_SUBOBJECT(void);
/* heap.c */
void __init lkdtm_heap_init(void);
void __exit lkdtm_heap_exit(void);
-void lkdtm_OVERWRITE_ALLOCATION(void);
+void lkdtm_VMALLOC_LINEAR_OVERFLOW(void);
+void lkdtm_SLAB_LINEAR_OVERFLOW(void);
void lkdtm_WRITE_AFTER_FREE(void);
void lkdtm_READ_AFTER_FREE(void);
void lkdtm_WRITE_BUDDY_AFTER_FREE(void);
diff --git a/tools/testing/selftests/lkdtm/tests.txt b/tools/testing/selftests/lkdtm/tests.txt
index 11ef159be0fd..322a1d2439e3 100644
--- a/tools/testing/selftests/lkdtm/tests.txt
+++ b/tools/testing/selftests/lkdtm/tests.txt
@@ -15,7 +15,8 @@ UNSET_SMEP CR4 bits went missing
DOUBLE_FAULT
CORRUPT_PAC
UNALIGNED_LOAD_STORE_WRITE
-#OVERWRITE_ALLOCATION Corrupts memory on failure
+VMALLOC_LINEAR_OVERFLOW
+SLAB_LINEAR_OVERFLOW
#WRITE_AFTER_FREE Corrupts memory on failure
READ_AFTER_FREE
#WRITE_BUDDY_AFTER_FREE Corrupts memory on failure
--
2.25.1