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 keescook@chromium.org --- 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