Commit 3bf301e1 authored by Kees Cook's avatar Kees Cook
Browse files

string: Add Kunit tests for strcat() family 



Add tests to make sure the strcat() family of functions behave
correctly.

Signed-off-by: default avatarKees Cook <keescook@chromium.org>
parent a9dc8d04

MAINTAINERS

+1 −0
Original line number Diff line number Diff line
@@ -8061,6 +8061,7 @@ T: git git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux.git for-next/har 
F:	include/linux/fortify-string.h

F:	lib/fortify_kunit.c

F:	lib/memcpy_kunit.c

F:	lib/strcat_kunit.c

F:	lib/strscpy_kunit.c

F:	lib/test_fortify/*

F:	scripts/test_fortify.sh

lib/Kconfig.debug

+5 −0
Original line number Diff line number Diff line
@@ -2662,6 +2662,11 @@ config HW_BREAKPOINT_KUNIT_TEST 


	  If unsure, say N.



config STRCAT_KUNIT_TEST

	tristate "Test strcat() family of functions at runtime" if !KUNIT_ALL_TESTS

	depends on KUNIT

	default KUNIT_ALL_TESTS



config STRSCPY_KUNIT_TEST

	tristate "Test strscpy*() family of functions at runtime" if !KUNIT_ALL_TESTS

	depends on KUNIT

lib/Makefile

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@@ -392,6 +392,7 @@ obj-$(CONFIG_STACKINIT_KUNIT_TEST) += stackinit_kunit.o 
CFLAGS_fortify_kunit.o += $(call cc-disable-warning, unsequenced)

CFLAGS_fortify_kunit.o += $(DISABLE_STRUCTLEAK_PLUGIN)

obj-$(CONFIG_FORTIFY_KUNIT_TEST) += fortify_kunit.o

obj-$(CONFIG_STRCAT_KUNIT_TEST) += strcat_kunit.o

obj-$(CONFIG_STRSCPY_KUNIT_TEST) += strscpy_kunit.o

obj-$(CONFIG_SIPHASH_KUNIT_TEST) += siphash_kunit.o

lib/strcat_kunit.c

0 → 100644
+104 −0
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// SPDX-License-Identifier: GPL-2.0

/*

 * Kernel module for testing 'strcat' family of functions.

 */



#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt



#include <kunit/test.h>

#include <linux/string.h>



static volatile int unconst;



static void strcat_test(struct kunit *test)

{

	char dest[8];



	/* Destination is terminated. */

	memset(dest, 0, sizeof(dest));

	KUNIT_EXPECT_EQ(test, strlen(dest), 0);

	/* Empty copy does nothing. */

	KUNIT_EXPECT_TRUE(test, strcat(dest, "") == dest);

	KUNIT_EXPECT_STREQ(test, dest, "");

	/* 4 characters copied in, stops at %NUL. */

	KUNIT_EXPECT_TRUE(test, strcat(dest, "four\000123") == dest);

	KUNIT_EXPECT_STREQ(test, dest, "four");

	KUNIT_EXPECT_EQ(test, dest[5], '\0');

	/* 2 more characters copied in okay. */

	KUNIT_EXPECT_TRUE(test, strcat(dest, "AB") == dest);

	KUNIT_EXPECT_STREQ(test, dest, "fourAB");

}



static void strncat_test(struct kunit *test)

{

	char dest[8];



	/* Destination is terminated. */

	memset(dest, 0, sizeof(dest));

	KUNIT_EXPECT_EQ(test, strlen(dest), 0);

	/* Empty copy of size 0 does nothing. */

	KUNIT_EXPECT_TRUE(test, strncat(dest, "", 0 + unconst) == dest);

	KUNIT_EXPECT_STREQ(test, dest, "");

	/* Empty copy of size 1 does nothing too. */

	KUNIT_EXPECT_TRUE(test, strncat(dest, "", 1 + unconst) == dest);

	KUNIT_EXPECT_STREQ(test, dest, "");

	/* Copy of max 0 characters should do nothing. */

	KUNIT_EXPECT_TRUE(test, strncat(dest, "asdf", 0 + unconst) == dest);

	KUNIT_EXPECT_STREQ(test, dest, "");



	/* 4 characters copied in, even if max is 8. */

	KUNIT_EXPECT_TRUE(test, strncat(dest, "four\000123", 8 + unconst) == dest);

	KUNIT_EXPECT_STREQ(test, dest, "four");

	KUNIT_EXPECT_EQ(test, dest[5], '\0');

	KUNIT_EXPECT_EQ(test, dest[6], '\0');

	/* 2 characters copied in okay, 2 ignored. */

	KUNIT_EXPECT_TRUE(test, strncat(dest, "ABCD", 2 + unconst) == dest);

	KUNIT_EXPECT_STREQ(test, dest, "fourAB");

}



static void strlcat_test(struct kunit *test)

{

	char dest[8] = "";

	int len = sizeof(dest) + unconst;



	/* Destination is terminated. */

	KUNIT_EXPECT_EQ(test, strlen(dest), 0);

	/* Empty copy is size 0. */

	KUNIT_EXPECT_EQ(test, strlcat(dest, "", len), 0);

	KUNIT_EXPECT_STREQ(test, dest, "");

	/* Size 1 should keep buffer terminated, report size of source only. */

	KUNIT_EXPECT_EQ(test, strlcat(dest, "four", 1 + unconst), 4);

	KUNIT_EXPECT_STREQ(test, dest, "");



	/* 4 characters copied in. */

	KUNIT_EXPECT_EQ(test, strlcat(dest, "four", len), 4);

	KUNIT_EXPECT_STREQ(test, dest, "four");

	/* 2 characters copied in okay, gets to 6 total. */

	KUNIT_EXPECT_EQ(test, strlcat(dest, "AB", len), 6);

	KUNIT_EXPECT_STREQ(test, dest, "fourAB");

	/* 2 characters ignored if max size (7) reached. */

	KUNIT_EXPECT_EQ(test, strlcat(dest, "CD", 7 + unconst), 8);

	KUNIT_EXPECT_STREQ(test, dest, "fourAB");

	/* 1 of 2 characters skipped, now at true max size. */

	KUNIT_EXPECT_EQ(test, strlcat(dest, "EFG", len), 9);

	KUNIT_EXPECT_STREQ(test, dest, "fourABE");

	/* Everything else ignored, now at full size. */

	KUNIT_EXPECT_EQ(test, strlcat(dest, "1234", len), 11);

	KUNIT_EXPECT_STREQ(test, dest, "fourABE");

}



static struct kunit_case strcat_test_cases[] = {

	KUNIT_CASE(strcat_test),

	KUNIT_CASE(strncat_test),

	KUNIT_CASE(strlcat_test),

	{}

};



static struct kunit_suite strcat_test_suite = {

	.name = "strcat",

	.test_cases = strcat_test_cases,

};



kunit_test_suite(strcat_test_suite);



MODULE_LICENSE("GPL");