diff options
| author | Kees Cook <keescook@chromium.org> | 2021-06-23 13:39:32 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-06-24 15:32:07 +0200 |
| commit | 9c4f6ebc3665b33f15ee97ba1eb2c9bed341b8e6 (patch) | |
| tree | ee929c0ca5be163d95c89008ade223ee80473d9c /drivers | |
| parent | a15676ac8f24a9ac5fd881cf17be4be13fa0910a (diff) | |
lkdtm/heap: Add vmalloc linear overflow test
Similar to the existing slab overflow and stack exhaustion tests, add
VMALLOC_LINEAR_OVERFLOW (and rename the slab test SLAB_LINEAR_OVERFLOW).
Additionally unmarks the test as destructive. (It should be safe in the
face of misbehavior.)
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20210623203936.3151093-6-keescook@chromium.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/misc/lkdtm/core.c | 3 | ||||
| -rw-r--r-- | drivers/misc/lkdtm/heap.c | 22 | ||||
| -rw-r--r-- | drivers/misc/lkdtm/lkdtm.h | 3 |
3 files changed, 25 insertions, 3 deletions
diff --git a/drivers/misc/lkdtm/core.c b/drivers/misc/lkdtm/core.c index 8024b6a5cc7f..645b31e98c77 100644 --- a/drivers/misc/lkdtm/core.c +++ b/drivers/misc/lkdtm/core.c @@ -120,7 +120,8 @@ 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..36be5e353cd0 100644 --- a/drivers/misc/lkdtm/heap.c +++ b/drivers/misc/lkdtm/heap.c @@ -5,6 +5,7 @@ */ #include "lkdtm.h" #include <linux/slab.h> +#include <linux/vmalloc.h> #include <linux/sched.h> static struct kmem_cache *double_free_cache; @@ -12,17 +13,36 @@ 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); if (!data) return; + pr_info("Attempting slab linear overflow ...\n"); data[1024 / sizeof(u32)] = 0x12345678; kfree(data); } diff --git a/drivers/misc/lkdtm/lkdtm.h b/drivers/misc/lkdtm/lkdtm.h index 99f90d3e5e9c..c6baf4f1e1db 100644 --- a/drivers/misc/lkdtm/lkdtm.h +++ b/drivers/misc/lkdtm/lkdtm.h @@ -39,7 +39,8 @@ 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); |