| Message ID | 20240610182301.work.272-kees@kernel.org (mailing list archive) |
|---|---|
| State | Mainlined |
| Commit | 9dd5134c61580ba4c219296c37e08ff64c109a74 |
| Headers | show |
| Series | kunit/overflow: Adjust for __counted_by with DEFINE_RAW_FLEX() | expand |
On Mon, Jun 10, 2024 at 11:23:05AM -0700, 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 <chrisi.schrefl@gmail.com> > Closes: https://lore.kernel.org/all/0bfc6b38-8bc5-4971-b6fb-dc642a73fbfe@gmail.com/ > Suggested-by: Nathan Chancellor <nathan@kernel.org> > Signed-off-by: Kees Cook <kees@kernel.org> Seems reasonable to me. Reviewed-by: Nathan Chancellor <nathan@kernel.org> > --- > Cc: "Gustavo A. R. Silva" <gustavoars@kernel.org> > Cc: linux-hardening@vger.kernel.org > --- > 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)); > } > -- > 2.34.1 >
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 <chrisi.schrefl@gmail.com> > Closes: https://lore.kernel.org/all/0bfc6b38-8bc5-4971-b6fb-dc642a73fbfe@gmail.com/ > Suggested-by: Nathan Chancellor <nathan@kernel.org> > Signed-off-by: Kees Cook <kees@kernel.org> > --- Thanks for the quick fix! Seems reasonable and the test passes now. Tested-by: Christian Schrefl <chrisi.schrefl@gmail.com> Reviewed-by: Christian Schrefl <chrisi.schrefl@gmail.com> > Cc: "Gustavo A. R. Silva" <gustavoars@kernel.org> > Cc: linux-hardening@vger.kernel.org > --- > 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)); > }
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)); }
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 <chrisi.schrefl@gmail.com> Closes: https://lore.kernel.org/all/0bfc6b38-8bc5-4971-b6fb-dc642a73fbfe@gmail.com/ Suggested-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Kees Cook <kees@kernel.org> --- Cc: "Gustavo A. R. Silva" <gustavoars@kernel.org> Cc: linux-hardening@vger.kernel.org --- lib/overflow_kunit.c | 20 +++++++++++++++++--- 1 file changed, 17 insertions(+), 3 deletions(-)