[v2] fortify: Add KUnit tests for runtime overflows

[PATCH v2 01/10] kunit: tool: Enable CONFIG_FORTIFY_SOURCE under UML

Posted by Kees Cook 2 years, 10 months ago

Since commit ba38961a069b ("um: Enable FORTIFY_SOURCE"), it's possible
to run the FORTIFY tests under UML. Enable CONFIG_FORTIFY_SOURCE when
running with --altests to gain additional coverage, and by default under
UML.

Signed-off-by: Kees Cook <keescook@chromium.org>
---
 tools/testing/kunit/configs/all_tests.config | 2 ++
 tools/testing/kunit/configs/arch_uml.config  | 3 +++
 2 files changed, 5 insertions(+)

diff --git a/tools/testing/kunit/configs/all_tests.config b/tools/testing/kunit/configs/all_tests.config
index f990cbb73250..0393940c706a 100644
--- a/tools/testing/kunit/configs/all_tests.config
+++ b/tools/testing/kunit/configs/all_tests.config
@@ -9,6 +9,8 @@ CONFIG_KUNIT=y
 CONFIG_KUNIT_EXAMPLE_TEST=y
 CONFIG_KUNIT_ALL_TESTS=y
 
+CONFIG_FORTIFY_SOURCE=y
+
 CONFIG_IIO=y
 
 CONFIG_EXT4_FS=y
diff --git a/tools/testing/kunit/configs/arch_uml.config b/tools/testing/kunit/configs/arch_uml.config
index e824ce43b05a..54ad8972681a 100644
--- a/tools/testing/kunit/configs/arch_uml.config
+++ b/tools/testing/kunit/configs/arch_uml.config
@@ -3,3 +3,6 @@
 # Enable virtio/pci, as a lot of tests require it.
 CONFIG_VIRTIO_UML=y
 CONFIG_UML_PCI_OVER_VIRTIO=y
+
+# Enable FORTIFY_SOURCE for wider checking.
+CONFIG_FORTIFY_SOURCE=y
-- 
2.34.1

Re: [PATCH v2 01/10] kunit: tool: Enable CONFIG_FORTIFY_SOURCE under UML

Posted by Nick Desaulniers 2 years, 10 months ago

On Fri, Apr 7, 2023 at 12:27 PM Kees Cook <keescook@chromium.org> wrote:
>
> Since commit ba38961a069b ("um: Enable FORTIFY_SOURCE"), it's possible
> to run the FORTIFY tests under UML. Enable CONFIG_FORTIFY_SOURCE when
> running with --altests to gain additional coverage, and by default under

two L's in alltest?

> UML.
>
> Signed-off-by: Kees Cook <keescook@chromium.org>
> ---
>  tools/testing/kunit/configs/all_tests.config | 2 ++
>  tools/testing/kunit/configs/arch_uml.config  | 3 +++
>  2 files changed, 5 insertions(+)
>
> diff --git a/tools/testing/kunit/configs/all_tests.config b/tools/testing/kunit/configs/all_tests.config
> index f990cbb73250..0393940c706a 100644
> --- a/tools/testing/kunit/configs/all_tests.config
> +++ b/tools/testing/kunit/configs/all_tests.config
> @@ -9,6 +9,8 @@ CONFIG_KUNIT=y
>  CONFIG_KUNIT_EXAMPLE_TEST=y
>  CONFIG_KUNIT_ALL_TESTS=y
>
> +CONFIG_FORTIFY_SOURCE=y
> +
>  CONFIG_IIO=y
>
>  CONFIG_EXT4_FS=y
> diff --git a/tools/testing/kunit/configs/arch_uml.config b/tools/testing/kunit/configs/arch_uml.config
> index e824ce43b05a..54ad8972681a 100644
> --- a/tools/testing/kunit/configs/arch_uml.config
> +++ b/tools/testing/kunit/configs/arch_uml.config
> @@ -3,3 +3,6 @@
>  # Enable virtio/pci, as a lot of tests require it.
>  CONFIG_VIRTIO_UML=y
>  CONFIG_UML_PCI_OVER_VIRTIO=y
> +
> +# Enable FORTIFY_SOURCE for wider checking.
> +CONFIG_FORTIFY_SOURCE=y
> --
> 2.34.1
>


-- 
Thanks,
~Nick Desaulniers

Re: [PATCH v2 01/10] kunit: tool: Enable CONFIG_FORTIFY_SOURCE under UML

Posted by Kees Cook 2 years, 9 months ago

On Fri, Apr 07, 2023 at 04:33:43PM -0700, Nick Desaulniers wrote:
> On Fri, Apr 7, 2023 at 12:27 PM Kees Cook <keescook@chromium.org> wrote:
> >
> > Since commit ba38961a069b ("um: Enable FORTIFY_SOURCE"), it's possible
> > to run the FORTIFY tests under UML. Enable CONFIG_FORTIFY_SOURCE when
> > running with --altests to gain additional coverage, and by default under
> 
> two L's in alltest?

Oops. Fixed. :)

-- 
Kees Cook

Re: [PATCH v2 01/10] kunit: tool: Enable CONFIG_FORTIFY_SOURCE under UML

Posted by Nick Desaulniers 2 years, 10 months ago

On Fri, Apr 7, 2023 at 4:33 PM Nick Desaulniers <ndesaulniers@google.com> wrote:
>
> On Fri, Apr 7, 2023 at 12:27 PM Kees Cook <keescook@chromium.org> wrote:
> >
> > Since commit ba38961a069b ("um: Enable FORTIFY_SOURCE"), it's possible
> > to run the FORTIFY tests under UML. Enable CONFIG_FORTIFY_SOURCE when
> > running with --altests to gain additional coverage, and by default under
>
> two L's in alltest?

Also, while testing this series:
```
$ LLVM=1 ./tools/testing/kunit/kunit.py run
...
[16:40:09] ================== fortify (24 subtests) ===================
[16:40:09] [PASSED] known_sizes_test
[16:40:09] [PASSED] control_flow_split_test
[16:40:09] [PASSED] alloc_size_kmalloc_const_test
[16:40:09]     # alloc_size_kmalloc_dynamic_test: EXPECTATION FAILED
at lib/fortify_kunit.c:249
[16:40:09]     Expected __builtin_dynamic_object_size(p, 1) == expected, but
[16:40:09]         __builtin_dynamic_object_size(p, 1) == -1
(0xffffffffffffffff)
[16:40:09]         expected == 11 (0xb)
[16:40:09] __alloc_size() not working with __bdos on kmemdup("hello
there", len, gfp)
[16:40:09] [FAILED] alloc_size_kmalloc_dynamic_test
[16:40:09] [PASSED] alloc_size_vmalloc_const_test
[16:40:09] [PASSED] alloc_size_vmalloc_dynamic_test
[16:40:09] [PASSED] alloc_size_kvmalloc_const_test
[16:40:09] [PASSED] alloc_size_kvmalloc_dynamic_test
[16:40:09] [PASSED] alloc_size_devm_kmalloc_const_test
[16:40:09] [PASSED] alloc_size_devm_kmalloc_dynamic_test
[16:40:09] [PASSED] strlen_test
[16:40:09] [PASSED] strnlen_test
[16:40:09] [PASSED] strcpy_test
[16:40:09] [PASSED] strncpy_test
[16:40:09] [PASSED] strlcpy_test
[16:40:09] [PASSED] strscpy_test
[16:40:09] [PASSED] strcat_test
[16:40:09] [PASSED] strncat_test
[16:40:09] [PASSED] strlcat_test
[16:40:09] [PASSED] memscan_test
[16:40:09] [PASSED] memchr_test
[16:40:09] [PASSED] memchr_inv_test
[16:40:09] [PASSED] memcmp_test
[16:40:09] [PASSED] kmemdup_test
[16:40:09] # fortify: pass:23 fail:1 skip:0 total:24
[16:40:09] # Totals: pass:23 fail:1 skip:0 total:24
[16:40:09] ===================== [FAILED] fortify =====================
```
It would be cool to understand that failure in BDOS BEFORE turning on
these tests by default.

>
> > UML.
> >
> > Signed-off-by: Kees Cook <keescook@chromium.org>
> > ---
> >  tools/testing/kunit/configs/all_tests.config | 2 ++
> >  tools/testing/kunit/configs/arch_uml.config  | 3 +++
> >  2 files changed, 5 insertions(+)
> >
> > diff --git a/tools/testing/kunit/configs/all_tests.config b/tools/testing/kunit/configs/all_tests.config
> > index f990cbb73250..0393940c706a 100644
> > --- a/tools/testing/kunit/configs/all_tests.config
> > +++ b/tools/testing/kunit/configs/all_tests.config
> > @@ -9,6 +9,8 @@ CONFIG_KUNIT=y
> >  CONFIG_KUNIT_EXAMPLE_TEST=y
> >  CONFIG_KUNIT_ALL_TESTS=y
> >
> > +CONFIG_FORTIFY_SOURCE=y
> > +
> >  CONFIG_IIO=y
> >
> >  CONFIG_EXT4_FS=y
> > diff --git a/tools/testing/kunit/configs/arch_uml.config b/tools/testing/kunit/configs/arch_uml.config
> > index e824ce43b05a..54ad8972681a 100644
> > --- a/tools/testing/kunit/configs/arch_uml.config
> > +++ b/tools/testing/kunit/configs/arch_uml.config
> > @@ -3,3 +3,6 @@
> >  # Enable virtio/pci, as a lot of tests require it.
> >  CONFIG_VIRTIO_UML=y
> >  CONFIG_UML_PCI_OVER_VIRTIO=y
> > +
> > +# Enable FORTIFY_SOURCE for wider checking.
> > +CONFIG_FORTIFY_SOURCE=y
> > --
> > 2.34.1
> >
>
>
> --
> Thanks,
> ~Nick Desaulniers



-- 
Thanks,
~Nick Desaulniers

Re: [PATCH v2 01/10] kunit: tool: Enable CONFIG_FORTIFY_SOURCE under UML

Posted by Kees Cook 2 years, 9 months ago

On Fri, Apr 07, 2023 at 04:42:27PM -0700, Nick Desaulniers wrote:
> On Fri, Apr 7, 2023 at 4:33 PM Nick Desaulniers <ndesaulniers@google.com> wrote:
> >
> > On Fri, Apr 7, 2023 at 12:27 PM Kees Cook <keescook@chromium.org> wrote:
> > >
> > > Since commit ba38961a069b ("um: Enable FORTIFY_SOURCE"), it's possible
> > > to run the FORTIFY tests under UML. Enable CONFIG_FORTIFY_SOURCE when
> > > running with --altests to gain additional coverage, and by default under
> >
> > two L's in alltest?
> 
> Also, while testing this series:
> ```
> $ LLVM=1 ./tools/testing/kunit/kunit.py run
> ...
> [16:40:09] ================== fortify (24 subtests) ===================
> [16:40:09] [PASSED] known_sizes_test
> [16:40:09] [PASSED] control_flow_split_test
> [16:40:09] [PASSED] alloc_size_kmalloc_const_test
> [16:40:09]     # alloc_size_kmalloc_dynamic_test: EXPECTATION FAILED
> at lib/fortify_kunit.c:249
> [16:40:09]     Expected __builtin_dynamic_object_size(p, 1) == expected, but
> [16:40:09]         __builtin_dynamic_object_size(p, 1) == -1
> (0xffffffffffffffff)
> [16:40:09]         expected == 11 (0xb)
> [16:40:09] __alloc_size() not working with __bdos on kmemdup("hello
> there", len, gfp)

I'm still tracking this down. I'm not sure what's happening here, but it
seems to be Clang-specific, and due to some interaction with the changes
I made for Kunit examination. WHY it happens I haven't found yet.

-- 
Kees Cook

Re: [PATCH v2 01/10] kunit: tool: Enable CONFIG_FORTIFY_SOURCE under UML

Posted by Nick Desaulniers 2 years, 8 months ago

On Wed, May 10, 2023 at 12:24 PM Kees Cook <keescook@chromium.org> wrote:
>
> On Fri, Apr 07, 2023 at 04:42:27PM -0700, Nick Desaulniers wrote:
> > On Fri, Apr 7, 2023 at 4:33 PM Nick Desaulniers <ndesaulniers@google.com> wrote:
> > >
> > > On Fri, Apr 7, 2023 at 12:27 PM Kees Cook <keescook@chromium.org> wrote:
> > > >
> > > > Since commit ba38961a069b ("um: Enable FORTIFY_SOURCE"), it's possible
> > > > to run the FORTIFY tests under UML. Enable CONFIG_FORTIFY_SOURCE when
> > > > running with --altests to gain additional coverage, and by default under
> > >
> > > two L's in alltest?
> >
> > Also, while testing this series:
> > ```
> > $ LLVM=1 ./tools/testing/kunit/kunit.py run
> > ...
> > [16:40:09] ================== fortify (24 subtests) ===================
> > [16:40:09] [PASSED] known_sizes_test
> > [16:40:09] [PASSED] control_flow_split_test
> > [16:40:09] [PASSED] alloc_size_kmalloc_const_test
> > [16:40:09]     # alloc_size_kmalloc_dynamic_test: EXPECTATION FAILED
> > at lib/fortify_kunit.c:249
> > [16:40:09]     Expected __builtin_dynamic_object_size(p, 1) == expected, but
> > [16:40:09]         __builtin_dynamic_object_size(p, 1) == -1
> > (0xffffffffffffffff)
> > [16:40:09]         expected == 11 (0xb)
> > [16:40:09] __alloc_size() not working with __bdos on kmemdup("hello
> > there", len, gfp)
>
> I'm still tracking this down. I'm not sure what's happening here, but it
> seems to be Clang-specific, and due to some interaction with the changes
> I made for Kunit examination. WHY it happens I haven't found yet.

Was this what exposed https://github.com/llvm/llvm-project/issues/62789?

-- 
Thanks,
~Nick Desaulniers

Re: [PATCH v2 01/10] kunit: tool: Enable CONFIG_FORTIFY_SOURCE under UML

Posted by Kees Cook 2 years, 8 months ago

On Mon, May 22, 2023 at 12:43:51PM -0700, Nick Desaulniers wrote:
> On Wed, May 10, 2023 at 12:24 PM Kees Cook <keescook@chromium.org> wrote:
> >
> > On Fri, Apr 07, 2023 at 04:42:27PM -0700, Nick Desaulniers wrote:
> > > On Fri, Apr 7, 2023 at 4:33 PM Nick Desaulniers <ndesaulniers@google.com> wrote:
> > > >
> > > > On Fri, Apr 7, 2023 at 12:27 PM Kees Cook <keescook@chromium.org> wrote:
> > > > >
> > > > > Since commit ba38961a069b ("um: Enable FORTIFY_SOURCE"), it's possible
> > > > > to run the FORTIFY tests under UML. Enable CONFIG_FORTIFY_SOURCE when
> > > > > running with --altests to gain additional coverage, and by default under
> > > >
> > > > two L's in alltest?
> > >
> > > Also, while testing this series:
> > > ```
> > > $ LLVM=1 ./tools/testing/kunit/kunit.py run
> > > ...
> > > [16:40:09] ================== fortify (24 subtests) ===================
> > > [16:40:09] [PASSED] known_sizes_test
> > > [16:40:09] [PASSED] control_flow_split_test
> > > [16:40:09] [PASSED] alloc_size_kmalloc_const_test
> > > [16:40:09]     # alloc_size_kmalloc_dynamic_test: EXPECTATION FAILED
> > > at lib/fortify_kunit.c:249
> > > [16:40:09]     Expected __builtin_dynamic_object_size(p, 1) == expected, but
> > > [16:40:09]         __builtin_dynamic_object_size(p, 1) == -1
> > > (0xffffffffffffffff)
> > > [16:40:09]         expected == 11 (0xb)
> > > [16:40:09] __alloc_size() not working with __bdos on kmemdup("hello
> > > there", len, gfp)
> >
> > I'm still tracking this down. I'm not sure what's happening here, but it
> > seems to be Clang-specific, and due to some interaction with the changes
> > I made for Kunit examination. WHY it happens I haven't found yet.
> 
> Was this what exposed https://github.com/llvm/llvm-project/issues/62789?

Nope -- I found this while working on:
https://lore.kernel.org/lkml/20230517225838.never.965-kees@kernel.org/

i.e. I was surprised I could use static initializers with a flexible
array, and then I went and verified various related behaviors between
GCC and Clang.

-- 
Kees Cook