// SPDX-License-Identifier: GPL-2.0
/*
- * Runtime test cases for CONFIG_FORTIFY_SOURCE that aren't expected to
- * Oops the kernel on success. (For those, see drivers/misc/lkdtm/fortify.c)
+ * Runtime test cases for CONFIG_FORTIFY_SOURCE. For testing memcpy(),
+ * see FORTIFY_MEM_* tests in LKDTM (drivers/misc/lkdtm/fortify.c).
*
* For corner cases with UBSAN, try testing with:
*
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+/* Redefine fortify_panic() to track failures. */
+void fortify_add_kunit_error(int write);
+#define fortify_panic(func, write, avail, size, retfail) do { \
+ __fortify_report(FORTIFY_REASON(func, write), avail, size); \
+ fortify_add_kunit_error(write); \
+ return (retfail); \
+} while (0)
+
#include <kunit/device.h>
#include <kunit/test.h>
+#include <kunit/test-bug.h>
#include <linux/device.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/vmalloc.h>
+/* Handle being built without CONFIG_FORTIFY_SOURCE */
+#ifndef __compiletime_strlen
+# define __compiletime_strlen __builtin_strlen
+#endif
+
+static struct kunit_resource read_resource;
+static struct kunit_resource write_resource;
+static int fortify_read_overflows;
+static int fortify_write_overflows;
+
static const char array_of_10[] = "this is 10";
static const char *ptr_of_11 = "this is 11!";
static char array_unknown[] = "compiler thinks I might change";
+void fortify_add_kunit_error(int write)
+{
+ struct kunit_resource *resource;
+ struct kunit *current_test;
+
+ current_test = kunit_get_current_test();
+ if (!current_test)
+ return;
+
+ resource = kunit_find_named_resource(current_test,
+ write ? "fortify_write_overflows"
+ : "fortify_read_overflows");
+ if (!resource)
+ return;
+
+ (*(int *)resource->data)++;
+ kunit_put_resource(resource);
+}
+
static void known_sizes_test(struct kunit *test)
{
KUNIT_EXPECT_EQ(test, __compiletime_strlen("88888888"), 8);
} while (0)
DEFINE_ALLOC_SIZE_TEST_PAIR(devm_kmalloc)
+/*
+ * We can't have an array at the end of a structure or else
+ * builds without -fstrict-flex-arrays=3 will report them as
+ * being an unknown length. Additionally, add bytes before
+ * and after the string to catch over/underflows if tests
+ * fail.
+ */
+struct fortify_padding {
+ unsigned long bytes_before;
+ char buf[32];
+ unsigned long bytes_after;
+};
+/* Force compiler into not being able to resolve size at compile-time. */
+static volatile int unconst;
+
+static void strlen_test(struct kunit *test)
+{
+ struct fortify_padding pad = { };
+ int i, end = sizeof(pad.buf) - 1;
+
+ /* Fill 31 bytes with valid characters. */
+ for (i = 0; i < sizeof(pad.buf) - 1; i++)
+ pad.buf[i] = i + '0';
+ /* Trailing bytes are still %NUL. */
+ KUNIT_EXPECT_EQ(test, pad.buf[end], '\0');
+ KUNIT_EXPECT_EQ(test, pad.bytes_after, 0);
+
+ /* String is terminated, so strlen() is valid. */
+ KUNIT_EXPECT_EQ(test, strlen(pad.buf), end);
+ KUNIT_EXPECT_EQ(test, fortify_read_overflows, 0);
+
+ /* Make string unterminated, and recount. */
+ pad.buf[end] = 'A';
+ end = sizeof(pad.buf);
+ KUNIT_EXPECT_EQ(test, strlen(pad.buf), end);
+ KUNIT_EXPECT_EQ(test, fortify_read_overflows, 1);
+}
+
+static void strnlen_test(struct kunit *test)
+{
+ struct fortify_padding pad = { };
+ int i, end = sizeof(pad.buf) - 1;
+
+ /* Fill 31 bytes with valid characters. */
+ for (i = 0; i < sizeof(pad.buf) - 1; i++)
+ pad.buf[i] = i + '0';
+ /* Trailing bytes are still %NUL. */
+ KUNIT_EXPECT_EQ(test, pad.buf[end], '\0');
+ KUNIT_EXPECT_EQ(test, pad.bytes_after, 0);
+
+ /* String is terminated, so strnlen() is valid. */
+ KUNIT_EXPECT_EQ(test, strnlen(pad.buf, sizeof(pad.buf)), end);
+ KUNIT_EXPECT_EQ(test, fortify_read_overflows, 0);
+ /* A truncated strnlen() will be safe, too. */
+ KUNIT_EXPECT_EQ(test, strnlen(pad.buf, sizeof(pad.buf) / 2),
+ sizeof(pad.buf) / 2);
+ KUNIT_EXPECT_EQ(test, fortify_read_overflows, 0);
+
+ /* Make string unterminated, and recount. */
+ pad.buf[end] = 'A';
+ end = sizeof(pad.buf);
+ /* Reading beyond with strncpy() will fail. */
+ KUNIT_EXPECT_EQ(test, strnlen(pad.buf, end + 1), end);
+ KUNIT_EXPECT_EQ(test, fortify_read_overflows, 1);
+ KUNIT_EXPECT_EQ(test, strnlen(pad.buf, end + 2), end);
+ KUNIT_EXPECT_EQ(test, fortify_read_overflows, 2);
+
+ /* Early-truncated is safe still, though. */
+ KUNIT_EXPECT_EQ(test, strnlen(pad.buf, end), end);
+ KUNIT_EXPECT_EQ(test, fortify_read_overflows, 2);
+
+ end = sizeof(pad.buf) / 2;
+ KUNIT_EXPECT_EQ(test, strnlen(pad.buf, end), end);
+ KUNIT_EXPECT_EQ(test, fortify_read_overflows, 2);
+}
+
+static void strcpy_test(struct kunit *test)
+{
+ struct fortify_padding pad = { };
+ char src[sizeof(pad.buf) + 1] = { };
+ int i;
+
+ /* Fill 31 bytes with valid characters. */
+ for (i = 0; i < sizeof(src) - 2; i++)
+ src[i] = i + '0';
+
+ /* Destination is %NUL-filled to start with. */
+ KUNIT_EXPECT_EQ(test, pad.bytes_before, 0);
+ KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 1], '\0');
+ KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 2], '\0');
+ KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 3], '\0');
+ KUNIT_EXPECT_EQ(test, pad.bytes_after, 0);
+
+ /* Legitimate strcpy() 1 less than of max size. */
+ KUNIT_ASSERT_TRUE(test, strcpy(pad.buf, src)
+ == pad.buf);
+ KUNIT_EXPECT_EQ(test, fortify_read_overflows, 0);
+ KUNIT_EXPECT_EQ(test, fortify_write_overflows, 0);
+ /* Only last byte should be %NUL */
+ KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 1], '\0');
+ KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 2], '\0');
+ KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 3], '\0');
+
+ src[sizeof(src) - 2] = 'A';
+ /* But now we trip the overflow checking. */
+ KUNIT_ASSERT_TRUE(test, strcpy(pad.buf, src)
+ == pad.buf);
+ KUNIT_EXPECT_EQ(test, fortify_read_overflows, 0);
+ KUNIT_EXPECT_EQ(test, fortify_write_overflows, 1);
+ /* Trailing %NUL -- thanks to FORTIFY. */
+ KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 1], '\0');
+ KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 2], '\0');
+ KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 2], '\0');
+ /* And we will not have gone beyond. */
+ KUNIT_EXPECT_EQ(test, pad.bytes_after, 0);
+
+ src[sizeof(src) - 1] = 'A';
+ /* And for sure now, two bytes past. */
+ KUNIT_ASSERT_TRUE(test, strcpy(pad.buf, src)
+ == pad.buf);
+ /*
+ * Which trips both the strlen() on the unterminated src,
+ * and the resulting copy attempt.
+ */
+ KUNIT_EXPECT_EQ(test, fortify_read_overflows, 1);
+ KUNIT_EXPECT_EQ(test, fortify_write_overflows, 2);
+ /* Trailing %NUL -- thanks to FORTIFY. */
+ KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 1], '\0');
+ KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 2], '\0');
+ KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 2], '\0');
+ /* And we will not have gone beyond. */
+ KUNIT_EXPECT_EQ(test, pad.bytes_after, 0);
+}
+
+static void strncpy_test(struct kunit *test)
+{
+ struct fortify_padding pad = { };
+ char src[] = "Copy me fully into a small buffer and I will overflow!";
+
+ /* Destination is %NUL-filled to start with. */
+ KUNIT_EXPECT_EQ(test, pad.bytes_before, 0);
+ KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 1], '\0');
+ KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 2], '\0');
+ KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 3], '\0');
+ KUNIT_EXPECT_EQ(test, pad.bytes_after, 0);
+
+ /* Legitimate strncpy() 1 less than of max size. */
+ KUNIT_ASSERT_TRUE(test, strncpy(pad.buf, src,
+ sizeof(pad.buf) + unconst - 1)
+ == pad.buf);
+ KUNIT_EXPECT_EQ(test, fortify_write_overflows, 0);
+ /* Only last byte should be %NUL */
+ KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 1], '\0');
+ KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 2], '\0');
+ KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 3], '\0');
+
+ /* Legitimate (though unterminated) max-size strncpy. */
+ KUNIT_ASSERT_TRUE(test, strncpy(pad.buf, src,
+ sizeof(pad.buf) + unconst)
+ == pad.buf);
+ KUNIT_EXPECT_EQ(test, fortify_write_overflows, 0);
+ /* No trailing %NUL -- thanks strncpy API. */
+ KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 1], '\0');
+ KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 2], '\0');
+ KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 2], '\0');
+ /* But we will not have gone beyond. */
+ KUNIT_EXPECT_EQ(test, pad.bytes_after, 0);
+
+ /* Now verify that FORTIFY is working... */
+ KUNIT_ASSERT_TRUE(test, strncpy(pad.buf, src,
+ sizeof(pad.buf) + unconst + 1)
+ == pad.buf);
+ /* Should catch the overflow. */
+ KUNIT_EXPECT_EQ(test, fortify_write_overflows, 1);
+ KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 1], '\0');
+ KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 2], '\0');
+ KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 2], '\0');
+ /* And we will not have gone beyond. */
+ KUNIT_EXPECT_EQ(test, pad.bytes_after, 0);
+
+ /* And further... */
+ KUNIT_ASSERT_TRUE(test, strncpy(pad.buf, src,
+ sizeof(pad.buf) + unconst + 2)
+ == pad.buf);
+ /* Should catch the overflow. */
+ KUNIT_EXPECT_EQ(test, fortify_write_overflows, 2);
+ KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 1], '\0');
+ KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 2], '\0');
+ KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 2], '\0');
+ /* And we will not have gone beyond. */
+ KUNIT_EXPECT_EQ(test, pad.bytes_after, 0);
+}
+
+static void strscpy_test(struct kunit *test)
+{
+ struct fortify_padding pad = { };
+ char src[] = "Copy me fully into a small buffer and I will overflow!";
+
+ /* Destination is %NUL-filled to start with. */
+ KUNIT_EXPECT_EQ(test, pad.bytes_before, 0);
+ KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 1], '\0');
+ KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 2], '\0');
+ KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 3], '\0');
+ KUNIT_EXPECT_EQ(test, pad.bytes_after, 0);
+
+ /* Legitimate strscpy() 1 less than of max size. */
+ KUNIT_ASSERT_EQ(test, strscpy(pad.buf, src,
+ sizeof(pad.buf) + unconst - 1),
+ -E2BIG);
+ KUNIT_EXPECT_EQ(test, fortify_write_overflows, 0);
+ /* Keeping space for %NUL, last two bytes should be %NUL */
+ KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 1], '\0');
+ KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 2], '\0');
+ KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 3], '\0');
+
+ /* Legitimate max-size strscpy. */
+ KUNIT_ASSERT_EQ(test, strscpy(pad.buf, src,
+ sizeof(pad.buf) + unconst),
+ -E2BIG);
+ KUNIT_EXPECT_EQ(test, fortify_write_overflows, 0);
+ /* A trailing %NUL will exist. */
+ KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 1], '\0');
+ KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 2], '\0');
+ KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 2], '\0');
+
+ /* Now verify that FORTIFY is working... */
+ KUNIT_ASSERT_EQ(test, strscpy(pad.buf, src,
+ sizeof(pad.buf) + unconst + 1),
+ -E2BIG);
+ /* Should catch the overflow. */
+ KUNIT_EXPECT_EQ(test, fortify_write_overflows, 1);
+ KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 1], '\0');
+ KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 2], '\0');
+ KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 2], '\0');
+ /* And we will not have gone beyond. */
+ KUNIT_EXPECT_EQ(test, pad.bytes_after, 0);
+
+ /* And much further... */
+ KUNIT_ASSERT_EQ(test, strscpy(pad.buf, src,
+ sizeof(src) * 2 + unconst),
+ -E2BIG);
+ /* Should catch the overflow. */
+ KUNIT_EXPECT_EQ(test, fortify_write_overflows, 2);
+ KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 1], '\0');
+ KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 2], '\0');
+ KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 2], '\0');
+ /* And we will not have gone beyond. */
+ KUNIT_EXPECT_EQ(test, pad.bytes_after, 0);
+}
+
+static void strcat_test(struct kunit *test)
+{
+ struct fortify_padding pad = { };
+ char src[sizeof(pad.buf) / 2] = { };
+ char one[] = "A";
+ char two[] = "BC";
+ int i;
+
+ /* Fill 15 bytes with valid characters. */
+ for (i = 0; i < sizeof(src) - 1; i++)
+ src[i] = i + 'A';
+
+ /* Destination is %NUL-filled to start with. */
+ KUNIT_EXPECT_EQ(test, pad.bytes_before, 0);
+ KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 1], '\0');
+ KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 2], '\0');
+ KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 3], '\0');
+ KUNIT_EXPECT_EQ(test, pad.bytes_after, 0);
+
+ /* Legitimate strcat() using less than half max size. */
+ KUNIT_ASSERT_TRUE(test, strcat(pad.buf, src) == pad.buf);
+ KUNIT_EXPECT_EQ(test, fortify_write_overflows, 0);
+ /* Legitimate strcat() now 2 bytes shy of end. */
+ KUNIT_ASSERT_TRUE(test, strcat(pad.buf, src) == pad.buf);
+ KUNIT_EXPECT_EQ(test, fortify_write_overflows, 0);
+ /* Last two bytes should be %NUL */
+ KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 1], '\0');
+ KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 2], '\0');
+ KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 3], '\0');
+
+ /* Add one more character to the end. */
+ KUNIT_ASSERT_TRUE(test, strcat(pad.buf, one) == pad.buf);
+ KUNIT_EXPECT_EQ(test, fortify_write_overflows, 0);
+ /* Last byte should be %NUL */
+ KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 1], '\0');
+ KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 2], '\0');
+ KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 3], '\0');
+
+ /* And this one char will overflow. */
+ KUNIT_ASSERT_TRUE(test, strcat(pad.buf, one) == pad.buf);
+ KUNIT_EXPECT_EQ(test, fortify_write_overflows, 1);
+ /* Last byte should be %NUL thanks to FORTIFY. */
+ KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 1], '\0');
+ KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 2], '\0');
+ KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 3], '\0');
+ KUNIT_EXPECT_EQ(test, pad.bytes_after, 0);
+
+ /* And adding two will overflow more. */
+ KUNIT_ASSERT_TRUE(test, strcat(pad.buf, two) == pad.buf);
+ KUNIT_EXPECT_EQ(test, fortify_write_overflows, 2);
+ /* Last byte should be %NUL thanks to FORTIFY. */
+ KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 1], '\0');
+ KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 2], '\0');
+ KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 3], '\0');
+ KUNIT_EXPECT_EQ(test, pad.bytes_after, 0);
+}
+
+static void strncat_test(struct kunit *test)
+{
+ struct fortify_padding pad = { };
+ char src[sizeof(pad.buf)] = { };
+ int i, partial;
+
+ /* Fill 31 bytes with valid characters. */
+ partial = sizeof(src) / 2 - 1;
+ for (i = 0; i < partial; i++)
+ src[i] = i + 'A';
+
+ /* Destination is %NUL-filled to start with. */
+ KUNIT_EXPECT_EQ(test, pad.bytes_before, 0);
+ KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 1], '\0');
+ KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 2], '\0');
+ KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 3], '\0');
+ KUNIT_EXPECT_EQ(test, pad.bytes_after, 0);
+
+ /* Legitimate strncat() using less than half max size. */
+ KUNIT_ASSERT_TRUE(test, strncat(pad.buf, src, partial) == pad.buf);
+ KUNIT_EXPECT_EQ(test, fortify_read_overflows, 0);
+ KUNIT_EXPECT_EQ(test, fortify_write_overflows, 0);
+ /* Legitimate strncat() now 2 bytes shy of end. */
+ KUNIT_ASSERT_TRUE(test, strncat(pad.buf, src, partial) == pad.buf);
+ KUNIT_EXPECT_EQ(test, fortify_read_overflows, 0);
+ KUNIT_EXPECT_EQ(test, fortify_write_overflows, 0);
+ /* Last two bytes should be %NUL */
+ KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 1], '\0');
+ KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 2], '\0');
+ KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 3], '\0');
+
+ /* Add one more character to the end. */
+ KUNIT_ASSERT_TRUE(test, strncat(pad.buf, src, 1) == pad.buf);
+ KUNIT_EXPECT_EQ(test, fortify_read_overflows, 0);
+ KUNIT_EXPECT_EQ(test, fortify_write_overflows, 0);
+ /* Last byte should be %NUL */
+ KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 1], '\0');
+ KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 2], '\0');
+ KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 3], '\0');
+
+ /* And this one char will overflow. */
+ KUNIT_ASSERT_TRUE(test, strncat(pad.buf, src, 1) == pad.buf);
+ KUNIT_EXPECT_EQ(test, fortify_read_overflows, 0);
+ KUNIT_EXPECT_EQ(test, fortify_write_overflows, 1);
+ /* Last byte should be %NUL thanks to FORTIFY. */
+ KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 1], '\0');
+ KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 2], '\0');
+ KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 3], '\0');
+ KUNIT_EXPECT_EQ(test, pad.bytes_after, 0);
+
+ /* And adding two will overflow more. */
+ KUNIT_ASSERT_TRUE(test, strncat(pad.buf, src, 2) == pad.buf);
+ KUNIT_EXPECT_EQ(test, fortify_read_overflows, 0);
+ KUNIT_EXPECT_EQ(test, fortify_write_overflows, 2);
+ /* Last byte should be %NUL thanks to FORTIFY. */
+ KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 1], '\0');
+ KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 2], '\0');
+ KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 3], '\0');
+ KUNIT_EXPECT_EQ(test, pad.bytes_after, 0);
+
+ /* Force an unterminated destination, and overflow. */
+ pad.buf[sizeof(pad.buf) - 1] = 'A';
+ KUNIT_ASSERT_TRUE(test, strncat(pad.buf, src, 1) == pad.buf);
+ /* This will have tripped both strlen() and strcat(). */
+ KUNIT_EXPECT_EQ(test, fortify_read_overflows, 1);
+ KUNIT_EXPECT_EQ(test, fortify_write_overflows, 3);
+ KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 1], '\0');
+ KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 2], '\0');
+ KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 3], '\0');
+ /* But we should not go beyond the end. */
+ KUNIT_EXPECT_EQ(test, pad.bytes_after, 0);
+}
+
+static void strlcat_test(struct kunit *test)
+{
+ struct fortify_padding pad = { };
+ char src[sizeof(pad.buf)] = { };
+ int i, partial;
+ int len = sizeof(pad.buf) + unconst;
+
+ /* Fill 15 bytes with valid characters. */
+ partial = sizeof(src) / 2 - 1;
+ for (i = 0; i < partial; i++)
+ src[i] = i + 'A';
+
+ /* Destination is %NUL-filled to start with. */
+ KUNIT_EXPECT_EQ(test, pad.bytes_before, 0);
+ KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 1], '\0');
+ KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 2], '\0');
+ KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 3], '\0');
+ KUNIT_EXPECT_EQ(test, pad.bytes_after, 0);
+
+ /* Legitimate strlcat() using less than half max size. */
+ KUNIT_ASSERT_EQ(test, strlcat(pad.buf, src, len), partial);
+ KUNIT_EXPECT_EQ(test, fortify_read_overflows, 0);
+ KUNIT_EXPECT_EQ(test, fortify_write_overflows, 0);
+ /* Legitimate strlcat() now 2 bytes shy of end. */
+ KUNIT_ASSERT_EQ(test, strlcat(pad.buf, src, len), partial * 2);
+ KUNIT_EXPECT_EQ(test, fortify_read_overflows, 0);
+ KUNIT_EXPECT_EQ(test, fortify_write_overflows, 0);
+ /* Last two bytes should be %NUL */
+ KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 1], '\0');
+ KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 2], '\0');
+ KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 3], '\0');
+
+ /* Add one more character to the end. */
+ KUNIT_ASSERT_EQ(test, strlcat(pad.buf, "Q", len), partial * 2 + 1);
+ KUNIT_EXPECT_EQ(test, fortify_read_overflows, 0);
+ KUNIT_EXPECT_EQ(test, fortify_write_overflows, 0);
+ /* Last byte should be %NUL */
+ KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 1], '\0');
+ KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 2], '\0');
+ KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 3], '\0');
+
+ /* And this one char will overflow. */
+ KUNIT_ASSERT_EQ(test, strlcat(pad.buf, "V", len * 2), len);
+ KUNIT_EXPECT_EQ(test, fortify_read_overflows, 0);
+ KUNIT_EXPECT_EQ(test, fortify_write_overflows, 1);
+ /* Last byte should be %NUL thanks to FORTIFY. */
+ KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 1], '\0');
+ KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 2], '\0');
+ KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 3], '\0');
+ KUNIT_EXPECT_EQ(test, pad.bytes_after, 0);
+
+ /* And adding two will overflow more. */
+ KUNIT_ASSERT_EQ(test, strlcat(pad.buf, "QQ", len * 2), len + 1);
+ KUNIT_EXPECT_EQ(test, fortify_read_overflows, 0);
+ KUNIT_EXPECT_EQ(test, fortify_write_overflows, 2);
+ /* Last byte should be %NUL thanks to FORTIFY. */
+ KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 1], '\0');
+ KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 2], '\0');
+ KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 3], '\0');
+ KUNIT_EXPECT_EQ(test, pad.bytes_after, 0);
+
+ /* Force an unterminated destination, and overflow. */
+ pad.buf[sizeof(pad.buf) - 1] = 'A';
+ KUNIT_ASSERT_EQ(test, strlcat(pad.buf, "TT", len * 2), len + 2);
+ /* This will have tripped both strlen() and strlcat(). */
+ KUNIT_EXPECT_EQ(test, fortify_read_overflows, 2);
+ KUNIT_EXPECT_EQ(test, fortify_write_overflows, 2);
+ KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 1], '\0');
+ KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 2], '\0');
+ KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 3], '\0');
+ /* But we should not go beyond the end. */
+ KUNIT_EXPECT_EQ(test, pad.bytes_after, 0);
+
+ /* Force an unterminated source, and overflow. */
+ memset(src, 'B', sizeof(src));
+ pad.buf[sizeof(pad.buf) - 1] = '\0';
+ KUNIT_ASSERT_EQ(test, strlcat(pad.buf, src, len * 3), len - 1 + sizeof(src));
+ /* This will have tripped both strlen() and strlcat(). */
+ KUNIT_EXPECT_EQ(test, fortify_read_overflows, 3);
+ KUNIT_EXPECT_EQ(test, fortify_write_overflows, 3);
+ KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 1], '\0');
+ /* But we should not go beyond the end. */
+ KUNIT_EXPECT_EQ(test, pad.bytes_after, 0);
+}
+
+static void memscan_test(struct kunit *test)
+{
+ char haystack[] = "Where oh where is my memory range?";
+ char *mem = haystack + strlen("Where oh where is ");
+ char needle = 'm';
+ size_t len = sizeof(haystack) + unconst;
+
+ KUNIT_ASSERT_PTR_EQ(test, memscan(haystack, needle, len),
+ mem);
+ KUNIT_EXPECT_EQ(test, fortify_read_overflows, 0);
+ /* Catch too-large range. */
+ KUNIT_ASSERT_PTR_EQ(test, memscan(haystack, needle, len + 1),
+ NULL);
+ KUNIT_EXPECT_EQ(test, fortify_read_overflows, 1);
+ KUNIT_ASSERT_PTR_EQ(test, memscan(haystack, needle, len * 2),
+ NULL);
+ KUNIT_EXPECT_EQ(test, fortify_read_overflows, 2);
+}
+
+static void memchr_test(struct kunit *test)
+{
+ char haystack[] = "Where oh where is my memory range?";
+ char *mem = haystack + strlen("Where oh where is ");
+ char needle = 'm';
+ size_t len = sizeof(haystack) + unconst;
+
+ KUNIT_ASSERT_PTR_EQ(test, memchr(haystack, needle, len),
+ mem);
+ KUNIT_EXPECT_EQ(test, fortify_read_overflows, 0);
+ /* Catch too-large range. */
+ KUNIT_ASSERT_PTR_EQ(test, memchr(haystack, needle, len + 1),
+ NULL);
+ KUNIT_EXPECT_EQ(test, fortify_read_overflows, 1);
+ KUNIT_ASSERT_PTR_EQ(test, memchr(haystack, needle, len * 2),
+ NULL);
+ KUNIT_EXPECT_EQ(test, fortify_read_overflows, 2);
+}
+
+static void memchr_inv_test(struct kunit *test)
+{
+ char haystack[] = "Where oh where is my memory range?";
+ char *mem = haystack + 1;
+ char needle = 'W';
+ size_t len = sizeof(haystack) + unconst;
+
+ /* Normal search is okay. */
+ KUNIT_ASSERT_PTR_EQ(test, memchr_inv(haystack, needle, len),
+ mem);
+ KUNIT_EXPECT_EQ(test, fortify_read_overflows, 0);
+ /* Catch too-large range. */
+ KUNIT_ASSERT_PTR_EQ(test, memchr_inv(haystack, needle, len + 1),
+ NULL);
+ KUNIT_EXPECT_EQ(test, fortify_read_overflows, 1);
+ KUNIT_ASSERT_PTR_EQ(test, memchr_inv(haystack, needle, len * 2),
+ NULL);
+ KUNIT_EXPECT_EQ(test, fortify_read_overflows, 2);
+}
+
+static void memcmp_test(struct kunit *test)
+{
+ char one[] = "My mind is going ...";
+ char two[] = "My mind is going ... I can feel it.";
+ size_t one_len = sizeof(one) + unconst - 1;
+ size_t two_len = sizeof(two) + unconst - 1;
+
+ /* We match the first string (ignoring the %NUL). */
+ KUNIT_ASSERT_EQ(test, memcmp(one, two, one_len), 0);
+ KUNIT_EXPECT_EQ(test, fortify_read_overflows, 0);
+ /* Still in bounds, but no longer matching. */
+ KUNIT_ASSERT_EQ(test, memcmp(one, two, one_len + 1), -32);
+ KUNIT_EXPECT_EQ(test, fortify_read_overflows, 0);
+
+ /* Catch too-large ranges. */
+ KUNIT_ASSERT_EQ(test, memcmp(one, two, one_len + 2), INT_MIN);
+ KUNIT_EXPECT_EQ(test, fortify_read_overflows, 1);
+
+ KUNIT_ASSERT_EQ(test, memcmp(two, one, two_len + 2), INT_MIN);
+ KUNIT_EXPECT_EQ(test, fortify_read_overflows, 2);
+}
+
+static void kmemdup_test(struct kunit *test)
+{
+ char src[] = "I got Doom running on it!";
+ char *copy;
+ size_t len = sizeof(src) + unconst;
+
+ /* Copy is within bounds. */
+ copy = kmemdup(src, len, GFP_KERNEL);
+ KUNIT_EXPECT_NOT_NULL(test, copy);
+ KUNIT_EXPECT_EQ(test, fortify_read_overflows, 0);
+ kfree(copy);
+
+ /* Without %NUL. */
+ copy = kmemdup(src, len - 1, GFP_KERNEL);
+ KUNIT_EXPECT_NOT_NULL(test, copy);
+ KUNIT_EXPECT_EQ(test, fortify_read_overflows, 0);
+ kfree(copy);
+
+ /* Tiny bounds. */
+ copy = kmemdup(src, 1, GFP_KERNEL);
+ KUNIT_EXPECT_NOT_NULL(test, copy);
+ KUNIT_EXPECT_EQ(test, fortify_read_overflows, 0);
+ kfree(copy);
+
+ /* Out of bounds by 1 byte. */
+ copy = kmemdup(src, len + 1, GFP_KERNEL);
+ KUNIT_EXPECT_NULL(test, copy);
+ KUNIT_EXPECT_EQ(test, fortify_read_overflows, 1);
+ kfree(copy);
+
+ /* Way out of bounds. */
+ copy = kmemdup(src, len * 2, GFP_KERNEL);
+ KUNIT_EXPECT_NULL(test, copy);
+ KUNIT_EXPECT_EQ(test, fortify_read_overflows, 2);
+ kfree(copy);
+
+ /* Starting offset causing out of bounds. */
+ copy = kmemdup(src + 1, len, GFP_KERNEL);
+ KUNIT_EXPECT_NULL(test, copy);
+ KUNIT_EXPECT_EQ(test, fortify_read_overflows, 3);
+ kfree(copy);
+}
+
+static int fortify_test_init(struct kunit *test)
+{
+ if (!IS_ENABLED(CONFIG_FORTIFY_SOURCE))
+ kunit_skip(test, "Not built with CONFIG_FORTIFY_SOURCE=y");
+
+ fortify_read_overflows = 0;
+ kunit_add_named_resource(test, NULL, NULL, &read_resource,
+ "fortify_read_overflows",
+ &fortify_read_overflows);
+ fortify_write_overflows = 0;
+ kunit_add_named_resource(test, NULL, NULL, &write_resource,
+ "fortify_write_overflows",
+ &fortify_write_overflows);
+ return 0;
+}
+
static struct kunit_case fortify_test_cases[] = {
KUNIT_CASE(known_sizes_test),
KUNIT_CASE(control_flow_split_test),
KUNIT_CASE(alloc_size_kvmalloc_dynamic_test),
KUNIT_CASE(alloc_size_devm_kmalloc_const_test),
KUNIT_CASE(alloc_size_devm_kmalloc_dynamic_test),
+ KUNIT_CASE(strlen_test),
+ KUNIT_CASE(strnlen_test),
+ KUNIT_CASE(strcpy_test),
+ KUNIT_CASE(strncpy_test),
+ KUNIT_CASE(strscpy_test),
+ KUNIT_CASE(strcat_test),
+ KUNIT_CASE(strncat_test),
+ KUNIT_CASE(strlcat_test),
+ /* skip memset: performs bounds checking on whole structs */
+ /* skip memcpy: still using warn-and-overwrite instead of hard-fail */
+ KUNIT_CASE(memscan_test),
+ KUNIT_CASE(memchr_test),
+ KUNIT_CASE(memchr_inv_test),
+ KUNIT_CASE(memcmp_test),
+ KUNIT_CASE(kmemdup_test),
{}
};
static struct kunit_suite fortify_test_suite = {
.name = "fortify",
+ .init = fortify_test_init,
.test_cases = fortify_test_cases,
};
projects / linux-block.git / blobdiff