On 10.06.24 8:23 PM, Kees Cook wrote: > When a flexible array structure has a __counted_by annotation, its use > with DEFINE_RAW_FLEX() will result in the count being zero-initialized. > This is expected since one doesn't want to use RAW with a counted_by > struct. Adjust the tests to check for the condition and for compiler > support. > > Reported-by: Christian Schrefl <[email protected]> > Closes: > https://lore.kernel.org/all/[email protected]/ > Suggested-by: Nathan Chancellor <[email protected]> > Signed-off-by: Kees Cook <[email protected]> > --- Thanks for the quick fix!
Seems reasonable and the test passes now. Tested-by: Christian Schrefl <[email protected]> Reviewed-by: Christian Schrefl <[email protected]> > Cc: "Gustavo A. R. Silva" <[email protected]> > Cc: [email protected] > --- > lib/overflow_kunit.c | 20 +++++++++++++++++--- > 1 file changed, 17 insertions(+), 3 deletions(-) > > diff --git a/lib/overflow_kunit.c b/lib/overflow_kunit.c > index 4ef31b0bb74d..d305b0c054bb 100644 > --- a/lib/overflow_kunit.c > +++ b/lib/overflow_kunit.c > @@ -1178,14 +1178,28 @@ struct foo { > s16 array[] __counted_by(counter); > }; > > +struct bar { > + int a; > + u32 counter; > + s16 array[]; > +}; > + > static void DEFINE_FLEX_test(struct kunit *test) > { > - DEFINE_RAW_FLEX(struct foo, two, array, 2); > + /* Using _RAW_ on a __counted_by struct will initialize "counter" to > zero */ > + DEFINE_RAW_FLEX(struct foo, two_but_zero, array, 2); > +#if __has_attribute(__counted_by__) > + int expected_raw_size = sizeof(struct foo); > +#else > + int expected_raw_size = sizeof(struct foo) + 2 * sizeof(s16); > +#endif > + /* Without annotation, it will always be on-stack size. */ > + DEFINE_RAW_FLEX(struct bar, two, array, 2); > DEFINE_FLEX(struct foo, eight, array, counter, 8); > DEFINE_FLEX(struct foo, empty, array, counter, 0); > > - KUNIT_EXPECT_EQ(test, __struct_size(two), > - sizeof(struct foo) + sizeof(s16) + sizeof(s16)); > + KUNIT_EXPECT_EQ(test, __struct_size(two_but_zero), expected_raw_size); > + KUNIT_EXPECT_EQ(test, __struct_size(two), sizeof(struct bar) + 2 * > sizeof(s16)); > KUNIT_EXPECT_EQ(test, __struct_size(eight), 24); > KUNIT_EXPECT_EQ(test, __struct_size(empty), sizeof(struct foo)); > }
