Re: [PATCH v8 7/7] selftest: test system mappings are sealed.

Jeff Xu
2025-03-03T19:47:33Z

On Mon, Mar 3, 2025 at 8:43 AM Lorenzo Stoakes
<lorenzo.stoakes@oracle.com> wrote:
>
> On Mon, Mar 03, 2025 at 12:08:49PM +0000, Lorenzo Stoakes wrote:
> >
> > On Mon, Mar 03, 2025 at 05:09:21AM +0000, jeffxu@chromium.org wrote:
> > > From: Jeff Xu <jeffxu@chromium.org>
> > >
> > > Add sysmap_is_sealed.c to test system mappings are sealed.
> > >
> > > Note: CONFIG_MSEAL_SYSTEM_MAPPINGS must be set, as indicated in
> > > config file.
> > >
> > > Signed-off-by: Jeff Xu <jeffxu@chromium.org>
> >
> > We do need to add this to the general selftests Makefile, but this code is
> > fine, so have a:
> >
> > Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
> >
> > Congratulations! :) and thanks for addressing the issues that were raised,
> > appreciate your efforts on this.
> >
> > Maybe you could send a fix patch? As it's such a small fix.
> >
> > Cheers, Lorenzo
> >
> >
> > > ---
> > > .../mseal_system_mappings/.gitignore | 2 +
> > > .../selftests/mseal_system_mappings/Makefile | 6 +
> > > .../selftests/mseal_system_mappings/config | 1 +
> > > .../mseal_system_mappings/sysmap_is_sealed.c | 113 ++++++++++++++++++
> >
> > Can you add this to tools/testing/selftests/Makefile? I _think_ adding:
> >
> > TARGETS += mm
> >
> > Should do it. Thanks!
>
> Obviously I meant to say:
>
> TARGETS += mseal_system_mappings
>
> Doh! :)
>
Yes. I will add that in v9.

This new selftest requires linux-kselftest@vger.kernel.org's approval.

As previously discussed [1], the KCONFIG: MSEAL_SYSTEM_MAPPINGS is
disabled by default. Hopefully, the selftest automation will be able
to detect and parse the "config" in the new
selftests/mseal_system_mappings/config at runtime.

Thanks
-Jeff
[1] https://lore.kernel.org/all/60f5b979-2969-4cb0-ad3d-262908869c5f@lucifer.local/

> >
> > > 4 files changed, 122 insertions(+)
> > > create mode 100644 tools/testing/selftests/mseal_system_mappings/.gitignore
> > > create mode 100644 tools/testing/selftests/mseal_system_mappings/Makefile
> > > create mode 100644 tools/testing/selftests/mseal_system_mappings/config
> > > create mode 100644 tools/testing/selftests/mseal_system_mappings/sysmap_is_sealed.c
> > >
> > > diff --git a/tools/testing/selftests/mseal_system_mappings/.gitignore b/tools/testing/selftests/mseal_system_mappings/.gitignore
> > > new file mode 100644
> > > index 000000000000..319c497a595e
> > > --- /dev/null
> > > +++ b/tools/testing/selftests/mseal_system_mappings/.gitignore
> > > @@ -0,0 +1,2 @@
> > > +# SPDX-License-Identifier: GPL-2.0-only
> > > +sysmap_is_sealed
> > > diff --git a/tools/testing/selftests/mseal_system_mappings/Makefile b/tools/testing/selftests/mseal_system_mappings/Makefile
> > > new file mode 100644
> > > index 000000000000..2b4504e2f52f
> > > --- /dev/null
> > > +++ b/tools/testing/selftests/mseal_system_mappings/Makefile
> > > @@ -0,0 +1,6 @@
> > > +# SPDX-License-Identifier: GPL-2.0-only
> > > +CFLAGS += -std=c99 -pthread -Wall $(KHDR_INCLUDES)
> > > +
> > > +TEST_GEN_PROGS := sysmap_is_sealed
> > > +
> > > +include ../lib.mk
> > > diff --git a/tools/testing/selftests/mseal_system_mappings/config b/tools/testing/selftests/mseal_system_mappings/config
> > > new file mode 100644
> > > index 000000000000..675cb9f37b86
> > > --- /dev/null
> > > +++ b/tools/testing/selftests/mseal_system_mappings/config
> > > @@ -0,0 +1 @@
> > > +CONFIG_MSEAL_SYSTEM_MAPPINGS=y
> > > diff --git a/tools/testing/selftests/mseal_system_mappings/sysmap_is_sealed.c b/tools/testing/selftests/mseal_system_mappings/sysmap_is_sealed.c
> > > new file mode 100644
> > > index 000000000000..c1e93794a58b
> > > --- /dev/null
> > > +++ b/tools/testing/selftests/mseal_system_mappings/sysmap_is_sealed.c
> > > @@ -0,0 +1,113 @@
> > > +// SPDX-License-Identifier: GPL-2.0-only
> > > +/*
> > > + * test system mappings are sealed when
> > > + * KCONFIG_MSEAL_SYSTEM_MAPPINGS=y
> > > + */
> > > +
> > > +#define _GNU_SOURCE
> > > +#include <stdio.h>
> > > +#include <errno.h>
> > > +#include <unistd.h>
> > > +#include <string.h>
> > > +#include <stdbool.h>
> > > +
> > > +#include "../kselftest.h"
> > > +#include "../kselftest_harness.h"
> > > +
> > > +#define VDSO_NAME "[vdso]"
> > > +#define VVAR_NAME "[vvar]"
> > > +#define VVAR_VCLOCK_NAME "[vvar_vclock]"
> > > +#define UPROBES_NAME "[uprobes]"
> > > +#define SIGPAGE_NAME "[sigpage]"
> > > +#define VECTORS_NAME "[vectors]"
> > > +
> > > +#define VMFLAGS "VmFlags:"
> > > +#define MSEAL_FLAGS "sl"
> > > +#define MAX_LINE_LEN 512
> > > +
> > > +bool has_mapping(char *name, FILE *maps)
> > > +{
> > > + char line[MAX_LINE_LEN];
> > > +
> > > + while (fgets(line, sizeof(line), maps)) {
> > > + if (strstr(line, name))
> > > + return true;
> > > + }
> > > +
> > > + return false;
> > > +}
> > > +
> > > +bool mapping_is_sealed(char *name, FILE *maps)
> > > +{
> > > + char line[MAX_LINE_LEN];
> > > +
> > > + while (fgets(line, sizeof(line), maps)) {
> > > + if (!strncmp(line, VMFLAGS, strlen(VMFLAGS))) {
> > > + if (strstr(line, MSEAL_FLAGS))
> > > + return true;
> > > +
> > > + return false;
> > > + }
> > > + }
> > > +
> > > + return false;
> > > +}
> > > +
> > > +FIXTURE(basic) {
> > > + FILE *maps;
> > > +};
> > > +
> > > +FIXTURE_SETUP(basic)
> > > +{
> > > + self->maps = fopen("/proc/self/smaps", "r");
> > > + if (!self->maps)
> > > + SKIP(return, "Could not open /proc/self/smap, errno=%d",
> > > + errno);
> > > +};
> > > +
> > > +FIXTURE_TEARDOWN(basic)
> > > +{
> > > + if (self->maps)
> > > + fclose(self->maps);
> > > +};
> > > +
> > > +FIXTURE_VARIANT(basic)
> > > +{
> > > + char *name;
> > > +};
> > > +
> > > +FIXTURE_VARIANT_ADD(basic, vdso) {
> > > + .name = VDSO_NAME,
> > > +};
> > > +
> > > +FIXTURE_VARIANT_ADD(basic, vvar) {
> > > + .name = VVAR_NAME,
> > > +};
> > > +
> > > +FIXTURE_VARIANT_ADD(basic, vvar_vclock) {
> > > + .name = VVAR_VCLOCK_NAME,
> > > +};
> > > +
> > > +FIXTURE_VARIANT_ADD(basic, sigpage) {
> > > + .name = SIGPAGE_NAME,
> > > +};
> > > +
> > > +FIXTURE_VARIANT_ADD(basic, vectors) {
> > > + .name = VECTORS_NAME,
> > > +};
> > > +
> > > +FIXTURE_VARIANT_ADD(basic, uprobes) {
> > > + .name = UPROBES_NAME,
> > > +};
> > > +
> > > +TEST_F(basic, is_sealed)
> > > +{
> > > + if (!has_mapping(variant->name, self->maps)) {
> > > + SKIP(return, "could not found the mapping, %s",
> > > + variant->name);
> > > + }
> > > +
> > > + EXPECT_TRUE(mapping_is_sealed(variant->name, self->maps));
> > > +};
> > > +
> > > +TEST_HARNESS_MAIN
> > > --
> > > 2.48.1.711.g2feabab25a-goog
> > >