aboutsummaryrefslogtreecommitdiff
path: root/lib
diff options
context:
space:
mode:
authorAndrey Ryabinin <aryabinin@virtuozzo.com>2018-10-26 15:02:34 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2018-10-26 16:25:18 -0700
commit0c96350a2d2f64fe777b444c995f6bb633c5d069 (patch)
tree84bffc58274336874b81d5f8de99e2011931d44c /lib
parent19a2ca0fb560fd7be7b5293c6b652c6d6078dcde (diff)
downloadlinux-0c96350a2d2f64fe777b444c995f6bb633c5d069.tar.gz
lib/test_kasan.c: add tests for several string/memory API functions
Arch code may have asm implementation of string/memory API functions instead of using generic one from lib/string.c. KASAN don't see memory accesses in asm code, thus can miss many bugs. E.g. on ARM64 KASAN don't see bugs in memchr(), memcmp(), str[r]chr(), str[n]cmp(), str[n]len(). Add tests for these functions to be sure that we notice the problem on other architectures. Link: http://lkml.kernel.org/r/20180920135631.23833-3-aryabinin@virtuozzo.com Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Alexander Potapenko <glider@google.com> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Kyeongdon Kim <kyeongdon.kim@lge.com> Cc: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'lib')
-rw-r--r--lib/test_kasan.c70
1 files changed, 70 insertions, 0 deletions
diff --git a/lib/test_kasan.c b/lib/test_kasan.c
index ec657105edbf..51b78405bf24 100644
--- a/lib/test_kasan.c
+++ b/lib/test_kasan.c
@@ -579,6 +579,73 @@ static noinline void __init kmem_cache_invalid_free(void)
kmem_cache_destroy(cache);
}
+static noinline void __init kasan_memchr(void)
+{
+ char *ptr;
+ size_t size = 24;
+
+ pr_info("out-of-bounds in memchr\n");
+ ptr = kmalloc(size, GFP_KERNEL | __GFP_ZERO);
+ if (!ptr)
+ return;
+
+ memchr(ptr, '1', size + 1);
+ kfree(ptr);
+}
+
+static noinline void __init kasan_memcmp(void)
+{
+ char *ptr;
+ size_t size = 24;
+ int arr[9];
+
+ pr_info("out-of-bounds in memcmp\n");
+ ptr = kmalloc(size, GFP_KERNEL | __GFP_ZERO);
+ if (!ptr)
+ return;
+
+ memset(arr, 0, sizeof(arr));
+ memcmp(ptr, arr, size+1);
+ kfree(ptr);
+}
+
+static noinline void __init kasan_strings(void)
+{
+ char *ptr;
+ size_t size = 24;
+
+ pr_info("use-after-free in strchr\n");
+ ptr = kmalloc(size, GFP_KERNEL | __GFP_ZERO);
+ if (!ptr)
+ return;
+
+ kfree(ptr);
+
+ /*
+ * Try to cause only 1 invalid access (less spam in dmesg).
+ * For that we need ptr to point to zeroed byte.
+ * Skip metadata that could be stored in freed object so ptr
+ * will likely point to zeroed byte.
+ */
+ ptr += 16;
+ strchr(ptr, '1');
+
+ pr_info("use-after-free in strrchr\n");
+ strrchr(ptr, '1');
+
+ pr_info("use-after-free in strcmp\n");
+ strcmp(ptr, "2");
+
+ pr_info("use-after-free in strncmp\n");
+ strncmp(ptr, "2", 1);
+
+ pr_info("use-after-free in strlen\n");
+ strlen(ptr);
+
+ pr_info("use-after-free in strnlen\n");
+ strnlen(ptr, 1);
+}
+
static int __init kmalloc_tests_init(void)
{
/*
@@ -618,6 +685,9 @@ static int __init kmalloc_tests_init(void)
use_after_scope_test();
kmem_cache_double_free();
kmem_cache_invalid_free();
+ kasan_memchr();
+ kasan_memcmp();
+ kasan_strings();
kasan_restore_multi_shot(multishot);