mirror of
https://github.com/torvalds/linux.git
synced 2025-08-15 22:21:42 +02:00
kunit/fortify: Replace "volatile" with OPTIMIZER_HIDE_VAR()
It does seem that using "volatile" isn't going to be sane compared to using OPTIMIZER_HIDE_VAR() going forward. Some strange interactions[1] with the sanitizers have been observed in the self-test code, so replace the logic. Reported-by: Nathan Chancellor <nathan@kernel.org> Closes: https://github.com/ClangBuiltLinux/linux/issues/2075 [1] Link: https://lore.kernel.org/r/20250312000439.work.112-kees@kernel.org Signed-off-by: Kees Cook <kees@kernel.org>
This commit is contained in:
Kees Cook
parent
416cf1f4d9
commit
6ee149f61b
1 changed files with 77 additions and 62 deletions
|
|
@ -411,8 +411,6 @@ struct fortify_padding {
|
|||
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 fortify_test_strlen(struct kunit *test)
|
||||
{
|
||||
|
|
@ -537,57 +535,56 @@ static void fortify_test_strncpy(struct kunit *test)
|
|||
{
|
||||
struct fortify_padding pad = { };
|
||||
char src[] = "Copy me fully into a small buffer and I will overflow!";
|
||||
size_t sizeof_buf = sizeof(pad.buf);
|
||||
|
||||
OPTIMIZER_HIDE_VAR(sizeof_buf);
|
||||
|
||||
/* 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.buf[sizeof_buf - 1], '\0');
|
||||
KUNIT_EXPECT_EQ(test, pad.buf[sizeof_buf - 2], '\0');
|
||||
KUNIT_EXPECT_EQ(test, pad.buf[sizeof_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)
|
||||
KUNIT_ASSERT_TRUE(test, strncpy(pad.buf, src, sizeof_buf - 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');
|
||||
KUNIT_EXPECT_EQ(test, pad.buf[sizeof_buf - 1], '\0');
|
||||
KUNIT_EXPECT_NE(test, pad.buf[sizeof_buf - 2], '\0');
|
||||
KUNIT_EXPECT_NE(test, pad.buf[sizeof_buf - 3], '\0');
|
||||
|
||||
/* Legitimate (though unterminated) max-size strncpy. */
|
||||
KUNIT_ASSERT_TRUE(test, strncpy(pad.buf, src,
|
||||
sizeof(pad.buf) + unconst)
|
||||
KUNIT_ASSERT_TRUE(test, strncpy(pad.buf, src, sizeof_buf)
|
||||
== 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');
|
||||
KUNIT_EXPECT_NE(test, pad.buf[sizeof_buf - 1], '\0');
|
||||
KUNIT_EXPECT_NE(test, pad.buf[sizeof_buf - 2], '\0');
|
||||
KUNIT_EXPECT_NE(test, pad.buf[sizeof_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)
|
||||
KUNIT_ASSERT_TRUE(test, strncpy(pad.buf, src, sizeof_buf + 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');
|
||||
KUNIT_EXPECT_NE(test, pad.buf[sizeof_buf - 1], '\0');
|
||||
KUNIT_EXPECT_NE(test, pad.buf[sizeof_buf - 2], '\0');
|
||||
KUNIT_EXPECT_NE(test, pad.buf[sizeof_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)
|
||||
KUNIT_ASSERT_TRUE(test, strncpy(pad.buf, src, sizeof_buf + 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');
|
||||
KUNIT_EXPECT_NE(test, pad.buf[sizeof_buf - 1], '\0');
|
||||
KUNIT_EXPECT_NE(test, pad.buf[sizeof_buf - 2], '\0');
|
||||
KUNIT_EXPECT_NE(test, pad.buf[sizeof_buf - 2], '\0');
|
||||
/* And we will not have gone beyond. */
|
||||
KUNIT_EXPECT_EQ(test, pad.bytes_after, 0);
|
||||
}
|
||||
|
|
@ -596,55 +593,56 @@ static void fortify_test_strscpy(struct kunit *test)
|
|||
{
|
||||
struct fortify_padding pad = { };
|
||||
char src[] = "Copy me fully into a small buffer and I will overflow!";
|
||||
size_t sizeof_buf = sizeof(pad.buf);
|
||||
size_t sizeof_src = sizeof(src);
|
||||
|
||||
OPTIMIZER_HIDE_VAR(sizeof_buf);
|
||||
OPTIMIZER_HIDE_VAR(sizeof_src);
|
||||
|
||||
/* 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.buf[sizeof_buf - 1], '\0');
|
||||
KUNIT_EXPECT_EQ(test, pad.buf[sizeof_buf - 2], '\0');
|
||||
KUNIT_EXPECT_EQ(test, pad.buf[sizeof_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),
|
||||
KUNIT_ASSERT_EQ(test, strscpy(pad.buf, src, sizeof_buf - 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');
|
||||
KUNIT_EXPECT_EQ(test, pad.buf[sizeof_buf - 1], '\0');
|
||||
KUNIT_EXPECT_EQ(test, pad.buf[sizeof_buf - 2], '\0');
|
||||
KUNIT_EXPECT_NE(test, pad.buf[sizeof_buf - 3], '\0');
|
||||
|
||||
/* Legitimate max-size strscpy. */
|
||||
KUNIT_ASSERT_EQ(test, strscpy(pad.buf, src,
|
||||
sizeof(pad.buf) + unconst),
|
||||
KUNIT_ASSERT_EQ(test, strscpy(pad.buf, src, sizeof_buf),
|
||||
-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');
|
||||
KUNIT_EXPECT_EQ(test, pad.buf[sizeof_buf - 1], '\0');
|
||||
KUNIT_EXPECT_NE(test, pad.buf[sizeof_buf - 2], '\0');
|
||||
KUNIT_EXPECT_NE(test, pad.buf[sizeof_buf - 2], '\0');
|
||||
|
||||
/* Now verify that FORTIFY is working... */
|
||||
KUNIT_ASSERT_EQ(test, strscpy(pad.buf, src,
|
||||
sizeof(pad.buf) + unconst + 1),
|
||||
KUNIT_ASSERT_EQ(test, strscpy(pad.buf, src, sizeof_buf + 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');
|
||||
KUNIT_EXPECT_EQ(test, pad.buf[sizeof_buf - 1], '\0');
|
||||
KUNIT_EXPECT_NE(test, pad.buf[sizeof_buf - 2], '\0');
|
||||
KUNIT_EXPECT_NE(test, pad.buf[sizeof_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),
|
||||
KUNIT_ASSERT_EQ(test, strscpy(pad.buf, src, sizeof_src * 2),
|
||||
-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');
|
||||
KUNIT_EXPECT_EQ(test, pad.buf[sizeof_buf - 1], '\0');
|
||||
KUNIT_EXPECT_NE(test, pad.buf[sizeof_buf - 2], '\0');
|
||||
KUNIT_EXPECT_NE(test, pad.buf[sizeof_buf - 2], '\0');
|
||||
/* And we will not have gone beyond. */
|
||||
KUNIT_EXPECT_EQ(test, pad.bytes_after, 0);
|
||||
}
|
||||
|
|
@ -784,7 +782,9 @@ static void fortify_test_strlcat(struct kunit *test)
|
|||
struct fortify_padding pad = { };
|
||||
char src[sizeof(pad.buf)] = { };
|
||||
int i, partial;
|
||||
int len = sizeof(pad.buf) + unconst;
|
||||
int len = sizeof(pad.buf);
|
||||
|
||||
OPTIMIZER_HIDE_VAR(len);
|
||||
|
||||
/* Fill 15 bytes with valid characters. */
|
||||
partial = sizeof(src) / 2 - 1;
|
||||
|
|
@ -874,28 +874,32 @@ struct fortify_zero_sized {
|
|||
#define __fortify_test(memfunc) \
|
||||
static void fortify_test_##memfunc(struct kunit *test) \
|
||||
{ \
|
||||
struct fortify_zero_sized zero = { }; \
|
||||
struct fortify_zero_sized empty = { }; \
|
||||
struct fortify_padding pad = { }; \
|
||||
char srcA[sizeof(pad.buf) + 2]; \
|
||||
char srcB[sizeof(pad.buf) + 2]; \
|
||||
size_t len = sizeof(pad.buf) + unconst; \
|
||||
size_t len = sizeof(pad.buf); \
|
||||
size_t zero = 0; \
|
||||
\
|
||||
OPTIMIZER_HIDE_VAR(len); \
|
||||
OPTIMIZER_HIDE_VAR(zero); \
|
||||
\
|
||||
memset(srcA, 'A', sizeof(srcA)); \
|
||||
KUNIT_ASSERT_EQ(test, srcA[0], 'A'); \
|
||||
memset(srcB, 'B', sizeof(srcB)); \
|
||||
KUNIT_ASSERT_EQ(test, srcB[0], 'B'); \
|
||||
\
|
||||
memfunc(pad.buf, srcA, 0 + unconst); \
|
||||
memfunc(pad.buf, srcA, zero); \
|
||||
KUNIT_EXPECT_EQ(test, pad.buf[0], '\0'); \
|
||||
KUNIT_EXPECT_EQ(test, fortify_read_overflows, 0); \
|
||||
KUNIT_EXPECT_EQ(test, fortify_write_overflows, 0); \
|
||||
memfunc(pad.buf + 1, srcB, 1 + unconst); \
|
||||
memfunc(pad.buf + 1, srcB, zero + 1); \
|
||||
KUNIT_EXPECT_EQ(test, pad.buf[0], '\0'); \
|
||||
KUNIT_EXPECT_EQ(test, pad.buf[1], 'B'); \
|
||||
KUNIT_EXPECT_EQ(test, pad.buf[2], '\0'); \
|
||||
KUNIT_EXPECT_EQ(test, fortify_read_overflows, 0); \
|
||||
KUNIT_EXPECT_EQ(test, fortify_write_overflows, 0); \
|
||||
memfunc(pad.buf, srcA, 1 + unconst); \
|
||||
memfunc(pad.buf, srcA, zero + 1); \
|
||||
KUNIT_EXPECT_EQ(test, pad.buf[0], 'A'); \
|
||||
KUNIT_EXPECT_EQ(test, pad.buf[1], 'B'); \
|
||||
KUNIT_EXPECT_EQ(test, fortify_read_overflows, 0); \
|
||||
|
|
@ -921,10 +925,10 @@ static void fortify_test_##memfunc(struct kunit *test) \
|
|||
/* Reset error counter. */ \
|
||||
fortify_write_overflows = 0; \
|
||||
/* Copy nothing into nothing: no errors. */ \
|
||||
memfunc(zero.buf, srcB, 0 + unconst); \
|
||||
memfunc(empty.buf, srcB, zero); \
|
||||
KUNIT_EXPECT_EQ(test, fortify_read_overflows, 0); \
|
||||
KUNIT_EXPECT_EQ(test, fortify_write_overflows, 0); \
|
||||
memfunc(zero.buf, srcB, 1 + unconst); \
|
||||
memfunc(empty.buf, srcB, zero + 1); \
|
||||
KUNIT_EXPECT_EQ(test, fortify_read_overflows, 0); \
|
||||
KUNIT_EXPECT_EQ(test, fortify_write_overflows, 1); \
|
||||
}
|
||||
|
|
@ -936,7 +940,9 @@ static void fortify_test_memscan(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;
|
||||
size_t len = sizeof(haystack);
|
||||
|
||||
OPTIMIZER_HIDE_VAR(len);
|
||||
|
||||
KUNIT_ASSERT_PTR_EQ(test, memscan(haystack, needle, len),
|
||||
mem);
|
||||
|
|
@ -955,7 +961,9 @@ static void fortify_test_memchr(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;
|
||||
size_t len = sizeof(haystack);
|
||||
|
||||
OPTIMIZER_HIDE_VAR(len);
|
||||
|
||||
KUNIT_ASSERT_PTR_EQ(test, memchr(haystack, needle, len),
|
||||
mem);
|
||||
|
|
@ -974,7 +982,9 @@ static void fortify_test_memchr_inv(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;
|
||||
size_t len = sizeof(haystack);
|
||||
|
||||
OPTIMIZER_HIDE_VAR(len);
|
||||
|
||||
/* Normal search is okay. */
|
||||
KUNIT_ASSERT_PTR_EQ(test, memchr_inv(haystack, needle, len),
|
||||
|
|
@ -993,8 +1003,11 @@ static void fortify_test_memcmp(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;
|
||||
size_t one_len = sizeof(one) - 1;
|
||||
size_t two_len = sizeof(two) - 1;
|
||||
|
||||
OPTIMIZER_HIDE_VAR(one_len);
|
||||
OPTIMIZER_HIDE_VAR(two_len);
|
||||
|
||||
/* We match the first string (ignoring the %NUL). */
|
||||
KUNIT_ASSERT_EQ(test, memcmp(one, two, one_len), 0);
|
||||
|
|
@ -1015,7 +1028,9 @@ static void fortify_test_kmemdup(struct kunit *test)
|
|||
{
|
||||
char src[] = "I got Doom running on it!";
|
||||
char *copy;
|
||||
size_t len = sizeof(src) + unconst;
|
||||
size_t len = sizeof(src);
|
||||
|
||||
OPTIMIZER_HIDE_VAR(len);
|
||||
|
||||
/* Copy is within bounds. */
|
||||
copy = kmemdup(src, len, GFP_KERNEL);
|
||||
|
|
|
|||
Loading…
Add table
Add a link
Reference in a new issue