[PATCH] fortify: Adjust KUnit test for modular build

From: Kees Cook
Date: Tue Sep 13 2022 - 14:20:24 EST


A much better "unknown size" string pointer is available directly from
struct test, so use that instead of a global that isn't shared with
modules.

Reported-by: Nathan Chancellor <nathan@xxxxxxxxxx>
Link: https://lore.kernel.org/lkml/YyCOHOchVuE/E7vS@dev-arch.thelio-3990X
Fixes: 875bfd5276f3 ("fortify: Add KUnit test for FORTIFY_SOURCE internals")
Cc: linux-hardening@xxxxxxxxxxxxxxx
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
---
Whoops! Thanks Nathan! :) This fixes it for your reproducer.
---
lib/fortify_kunit.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/lib/fortify_kunit.c b/lib/fortify_kunit.c
index 99bc0ea60d27..409af07f340a 100644
--- a/lib/fortify_kunit.c
+++ b/lib/fortify_kunit.c
@@ -17,7 +17,6 @@

#include <kunit/test.h>
#include <linux/string.h>
-#include <linux/init.h>

static const char array_of_10[] = "this is 10";
static const char *ptr_of_11 = "this is 11!";
@@ -31,7 +30,7 @@ static void known_sizes_test(struct kunit *test)

KUNIT_EXPECT_EQ(test, __compiletime_strlen(array_unknown), SIZE_MAX);
/* Externally defined and dynamically sized string pointer: */
- KUNIT_EXPECT_EQ(test, __compiletime_strlen(saved_command_line), SIZE_MAX);
+ KUNIT_EXPECT_EQ(test, __compiletime_strlen(test->name), SIZE_MAX);
}

/* This is volatile so the optimizer can't perform DCE below. */
--
2.34.1