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fortify: Add KUnit tests for runtime overflows
With fortify overflows able to be redirected, we can use KUnit to exercise the overflow conditions. Add tests for every API covered by CONFIG_FORTIFY_SOURCE, except for memset() and memcpy(), which are special-cased for now. Disable warnings in the Makefile since we're explicitly testing known-bad string handling code patterns. Note that this makes the LKDTM FORTIFY_STR* tests obsolete, but those can be removed separately. Signed-off-by: Kees Cook <keescook@chromium.org>
This commit is contained in:
Kees Cook
parent
4ce615e798
commit
fa4a3f86d4
@ -402,6 +402,8 @@ obj-$(CONFIG_OVERFLOW_KUNIT_TEST) += overflow_kunit.o
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CFLAGS_stackinit_kunit.o += $(call cc-disable-warning, switch-unreachable)
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obj-$(CONFIG_STACKINIT_KUNIT_TEST) += stackinit_kunit.o
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CFLAGS_fortify_kunit.o += $(call cc-disable-warning, unsequenced)
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CFLAGS_fortify_kunit.o += $(call cc-disable-warning, stringop-overread)
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CFLAGS_fortify_kunit.o += $(call cc-disable-warning, stringop-truncation)
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CFLAGS_fortify_kunit.o += $(DISABLE_STRUCTLEAK_PLUGIN)
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obj-$(CONFIG_FORTIFY_KUNIT_TEST) += fortify_kunit.o
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obj-$(CONFIG_STRCAT_KUNIT_TEST) += strcat_kunit.o
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@ -1,7 +1,7 @@
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// SPDX-License-Identifier: GPL-2.0
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/*
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* Runtime test cases for CONFIG_FORTIFY_SOURCE that aren't expected to
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* Oops the kernel on success. (For those, see drivers/misc/lkdtm/fortify.c)
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* Runtime test cases for CONFIG_FORTIFY_SOURCE. For testing memcpy(),
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* see FORTIFY_MEM_* tests in LKDTM (drivers/misc/lkdtm/fortify.c).
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*
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* For corner cases with UBSAN, try testing with:
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*
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@ -346,6 +346,594 @@ DEFINE_ALLOC_SIZE_TEST_PAIR(kvmalloc)
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} while (0)
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DEFINE_ALLOC_SIZE_TEST_PAIR(devm_kmalloc)
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/*
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* We can't have an array at the end of a structure or else
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* builds without -fstrict-flex-arrays=3 will report them as
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* being an unknown length. Additionally, add bytes before
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* and after the string to catch over/underflows if tests
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* fail.
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*/
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struct fortify_padding {
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unsigned long bytes_before;
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char buf[32];
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unsigned long bytes_after;
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};
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/* Force compiler into not being able to resolve size at compile-time. */
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static volatile int unconst;
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static void strlen_test(struct kunit *test)
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{
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struct fortify_padding pad = { };
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int i, end = sizeof(pad.buf) - 1;
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/* Fill 31 bytes with valid characters. */
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for (i = 0; i < sizeof(pad.buf) - 1; i++)
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pad.buf[i] = i + '0';
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/* Trailing bytes are still %NUL. */
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KUNIT_EXPECT_EQ(test, pad.buf[end], '\0');
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KUNIT_EXPECT_EQ(test, pad.bytes_after, 0);
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/* String is terminated, so strlen() is valid. */
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KUNIT_EXPECT_EQ(test, strlen(pad.buf), end);
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KUNIT_EXPECT_EQ(test, fortify_read_overflows, 0);
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/* Make string unterminated, and recount. */
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pad.buf[end] = 'A';
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end = sizeof(pad.buf);
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KUNIT_EXPECT_EQ(test, strlen(pad.buf), end);
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KUNIT_EXPECT_EQ(test, fortify_read_overflows, 1);
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}
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static void strnlen_test(struct kunit *test)
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{
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struct fortify_padding pad = { };
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int i, end = sizeof(pad.buf) - 1;
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/* Fill 31 bytes with valid characters. */
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for (i = 0; i < sizeof(pad.buf) - 1; i++)
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pad.buf[i] = i + '0';
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/* Trailing bytes are still %NUL. */
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KUNIT_EXPECT_EQ(test, pad.buf[end], '\0');
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KUNIT_EXPECT_EQ(test, pad.bytes_after, 0);
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/* String is terminated, so strnlen() is valid. */
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KUNIT_EXPECT_EQ(test, strnlen(pad.buf, sizeof(pad.buf)), end);
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KUNIT_EXPECT_EQ(test, fortify_read_overflows, 0);
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/* A truncated strnlen() will be safe, too. */
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KUNIT_EXPECT_EQ(test, strnlen(pad.buf, sizeof(pad.buf) / 2),
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sizeof(pad.buf) / 2);
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KUNIT_EXPECT_EQ(test, fortify_read_overflows, 0);
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/* Make string unterminated, and recount. */
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pad.buf[end] = 'A';
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end = sizeof(pad.buf);
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/* Reading beyond with strncpy() will fail. */
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KUNIT_EXPECT_EQ(test, strnlen(pad.buf, end + 1), end);
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KUNIT_EXPECT_EQ(test, fortify_read_overflows, 1);
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KUNIT_EXPECT_EQ(test, strnlen(pad.buf, end + 2), end);
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KUNIT_EXPECT_EQ(test, fortify_read_overflows, 2);
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/* Early-truncated is safe still, though. */
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KUNIT_EXPECT_EQ(test, strnlen(pad.buf, end), end);
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KUNIT_EXPECT_EQ(test, fortify_read_overflows, 2);
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end = sizeof(pad.buf) / 2;
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KUNIT_EXPECT_EQ(test, strnlen(pad.buf, end), end);
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KUNIT_EXPECT_EQ(test, fortify_read_overflows, 2);
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}
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static void strcpy_test(struct kunit *test)
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{
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struct fortify_padding pad = { };
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char src[sizeof(pad.buf) + 1] = { };
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int i;
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/* Fill 31 bytes with valid characters. */
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for (i = 0; i < sizeof(src) - 2; i++)
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src[i] = i + '0';
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/* Destination is %NUL-filled to start with. */
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KUNIT_EXPECT_EQ(test, pad.bytes_before, 0);
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KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 1], '\0');
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KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 2], '\0');
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KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 3], '\0');
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KUNIT_EXPECT_EQ(test, pad.bytes_after, 0);
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/* Legitimate strcpy() 1 less than of max size. */
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KUNIT_ASSERT_TRUE(test, strcpy(pad.buf, src)
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== pad.buf);
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KUNIT_EXPECT_EQ(test, fortify_read_overflows, 0);
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KUNIT_EXPECT_EQ(test, fortify_write_overflows, 0);
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/* Only last byte should be %NUL */
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KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 1], '\0');
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KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 2], '\0');
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KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 3], '\0');
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src[sizeof(src) - 2] = 'A';
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/* But now we trip the overflow checking. */
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KUNIT_ASSERT_TRUE(test, strcpy(pad.buf, src)
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== pad.buf);
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KUNIT_EXPECT_EQ(test, fortify_read_overflows, 0);
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KUNIT_EXPECT_EQ(test, fortify_write_overflows, 1);
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/* Trailing %NUL -- thanks to FORTIFY. */
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KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 1], '\0');
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KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 2], '\0');
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KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 2], '\0');
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/* And we will not have gone beyond. */
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KUNIT_EXPECT_EQ(test, pad.bytes_after, 0);
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src[sizeof(src) - 1] = 'A';
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/* And for sure now, two bytes past. */
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KUNIT_ASSERT_TRUE(test, strcpy(pad.buf, src)
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== pad.buf);
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/*
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* Which trips both the strlen() on the unterminated src,
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* and the resulting copy attempt.
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*/
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KUNIT_EXPECT_EQ(test, fortify_read_overflows, 1);
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KUNIT_EXPECT_EQ(test, fortify_write_overflows, 2);
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/* Trailing %NUL -- thanks to FORTIFY. */
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KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 1], '\0');
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KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 2], '\0');
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KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 2], '\0');
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/* And we will not have gone beyond. */
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KUNIT_EXPECT_EQ(test, pad.bytes_after, 0);
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}
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static void strncpy_test(struct kunit *test)
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{
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struct fortify_padding pad = { };
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char src[] = "Copy me fully into a small buffer and I will overflow!";
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/* Destination is %NUL-filled to start with. */
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KUNIT_EXPECT_EQ(test, pad.bytes_before, 0);
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KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 1], '\0');
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KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 2], '\0');
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KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 3], '\0');
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KUNIT_EXPECT_EQ(test, pad.bytes_after, 0);
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/* Legitimate strncpy() 1 less than of max size. */
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KUNIT_ASSERT_TRUE(test, strncpy(pad.buf, src,
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sizeof(pad.buf) + unconst - 1)
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== pad.buf);
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KUNIT_EXPECT_EQ(test, fortify_write_overflows, 0);
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/* Only last byte should be %NUL */
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KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 1], '\0');
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KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 2], '\0');
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KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 3], '\0');
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/* Legitimate (though unterminated) max-size strncpy. */
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KUNIT_ASSERT_TRUE(test, strncpy(pad.buf, src,
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sizeof(pad.buf) + unconst)
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== pad.buf);
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KUNIT_EXPECT_EQ(test, fortify_write_overflows, 0);
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/* No trailing %NUL -- thanks strncpy API. */
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KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 1], '\0');
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KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 2], '\0');
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KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 2], '\0');
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/* But we will not have gone beyond. */
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KUNIT_EXPECT_EQ(test, pad.bytes_after, 0);
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/* Now verify that FORTIFY is working... */
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KUNIT_ASSERT_TRUE(test, strncpy(pad.buf, src,
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sizeof(pad.buf) + unconst + 1)
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== pad.buf);
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/* Should catch the overflow. */
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KUNIT_EXPECT_EQ(test, fortify_write_overflows, 1);
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KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 1], '\0');
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KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 2], '\0');
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KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 2], '\0');
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/* And we will not have gone beyond. */
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KUNIT_EXPECT_EQ(test, pad.bytes_after, 0);
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/* And further... */
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KUNIT_ASSERT_TRUE(test, strncpy(pad.buf, src,
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sizeof(pad.buf) + unconst + 2)
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== pad.buf);
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/* Should catch the overflow. */
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KUNIT_EXPECT_EQ(test, fortify_write_overflows, 2);
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KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 1], '\0');
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KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 2], '\0');
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KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 2], '\0');
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/* And we will not have gone beyond. */
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KUNIT_EXPECT_EQ(test, pad.bytes_after, 0);
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}
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static void strscpy_test(struct kunit *test)
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{
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struct fortify_padding pad = { };
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char src[] = "Copy me fully into a small buffer and I will overflow!";
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/* Destination is %NUL-filled to start with. */
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KUNIT_EXPECT_EQ(test, pad.bytes_before, 0);
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KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 1], '\0');
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KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 2], '\0');
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KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 3], '\0');
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KUNIT_EXPECT_EQ(test, pad.bytes_after, 0);
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/* Legitimate strscpy() 1 less than of max size. */
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KUNIT_ASSERT_EQ(test, strscpy(pad.buf, src,
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sizeof(pad.buf) + unconst - 1),
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-E2BIG);
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KUNIT_EXPECT_EQ(test, fortify_write_overflows, 0);
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/* Keeping space for %NUL, last two bytes should be %NUL */
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KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 1], '\0');
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KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 2], '\0');
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KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 3], '\0');
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/* Legitimate max-size strscpy. */
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KUNIT_ASSERT_EQ(test, strscpy(pad.buf, src,
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sizeof(pad.buf) + unconst),
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-E2BIG);
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KUNIT_EXPECT_EQ(test, fortify_write_overflows, 0);
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/* A trailing %NUL will exist. */
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KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 1], '\0');
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KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 2], '\0');
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KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 2], '\0');
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/* Now verify that FORTIFY is working... */
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KUNIT_ASSERT_EQ(test, strscpy(pad.buf, src,
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sizeof(pad.buf) + unconst + 1),
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-E2BIG);
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/* Should catch the overflow. */
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KUNIT_EXPECT_EQ(test, fortify_write_overflows, 1);
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KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 1], '\0');
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KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 2], '\0');
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KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 2], '\0');
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/* And we will not have gone beyond. */
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KUNIT_EXPECT_EQ(test, pad.bytes_after, 0);
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/* And much further... */
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KUNIT_ASSERT_EQ(test, strscpy(pad.buf, src,
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sizeof(src) * 2 + unconst),
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-E2BIG);
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/* Should catch the overflow. */
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KUNIT_EXPECT_EQ(test, fortify_write_overflows, 2);
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KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 1], '\0');
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KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 2], '\0');
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KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 2], '\0');
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/* And we will not have gone beyond. */
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KUNIT_EXPECT_EQ(test, pad.bytes_after, 0);
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}
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static void strcat_test(struct kunit *test)
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{
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struct fortify_padding pad = { };
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char src[sizeof(pad.buf) / 2] = { };
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char one[] = "A";
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char two[] = "BC";
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int i;
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/* Fill 15 bytes with valid characters. */
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for (i = 0; i < sizeof(src) - 1; i++)
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src[i] = i + 'A';
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/* Destination is %NUL-filled to start with. */
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KUNIT_EXPECT_EQ(test, pad.bytes_before, 0);
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KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 1], '\0');
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KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 2], '\0');
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KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 3], '\0');
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KUNIT_EXPECT_EQ(test, pad.bytes_after, 0);
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/* Legitimate strcat() using less than half max size. */
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KUNIT_ASSERT_TRUE(test, strcat(pad.buf, src) == pad.buf);
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KUNIT_EXPECT_EQ(test, fortify_write_overflows, 0);
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/* Legitimate strcat() now 2 bytes shy of end. */
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KUNIT_ASSERT_TRUE(test, strcat(pad.buf, src) == pad.buf);
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KUNIT_EXPECT_EQ(test, fortify_write_overflows, 0);
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/* Last two bytes should be %NUL */
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KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 1], '\0');
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KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 2], '\0');
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KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 3], '\0');
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/* Add one more character to the end. */
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KUNIT_ASSERT_TRUE(test, strcat(pad.buf, one) == pad.buf);
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KUNIT_EXPECT_EQ(test, fortify_write_overflows, 0);
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/* Last byte should be %NUL */
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KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 1], '\0');
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KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 2], '\0');
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KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 3], '\0');
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/* And this one char will overflow. */
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KUNIT_ASSERT_TRUE(test, strcat(pad.buf, one) == pad.buf);
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KUNIT_EXPECT_EQ(test, fortify_write_overflows, 1);
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/* Last byte should be %NUL thanks to FORTIFY. */
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KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 1], '\0');
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KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 2], '\0');
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KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 3], '\0');
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KUNIT_EXPECT_EQ(test, pad.bytes_after, 0);
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/* And adding two will overflow more. */
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KUNIT_ASSERT_TRUE(test, strcat(pad.buf, two) == pad.buf);
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KUNIT_EXPECT_EQ(test, fortify_write_overflows, 2);
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/* Last byte should be %NUL thanks to FORTIFY. */
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KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 1], '\0');
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KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 2], '\0');
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KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 3], '\0');
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KUNIT_EXPECT_EQ(test, pad.bytes_after, 0);
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}
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static void strncat_test(struct kunit *test)
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{
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struct fortify_padding pad = { };
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char src[sizeof(pad.buf)] = { };
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int i, partial;
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/* Fill 31 bytes with valid characters. */
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partial = sizeof(src) / 2 - 1;
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for (i = 0; i < partial; i++)
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src[i] = i + 'A';
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/* Destination is %NUL-filled to start with. */
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KUNIT_EXPECT_EQ(test, pad.bytes_before, 0);
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KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 1], '\0');
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KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 2], '\0');
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KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 3], '\0');
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KUNIT_EXPECT_EQ(test, pad.bytes_after, 0);
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/* 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))
|
||||
@ -373,6 +961,21 @@ static struct kunit_case fortify_test_cases[] = {
|
||||
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),
|
||||
{}
|
||||
};
|
||||
|
||||
|
||||
Loading…
Reference in New Issue
Block a user