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

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Message-ID: <d945816e-b01f-4a7c-b698-23ec356280f3@lucifer.local>
Date: Mon, 3 Mar 2025 12:08:49 +0000
From: Lorenzo Stoakes <lorenzo.stoakes@...cle.com>
To: jeffxu@...omium.org
Cc: akpm@...ux-foundation.org, keescook@...omium.org, jannh@...gle.com,
        torvalds@...ux-foundation.org, vbabka@...e.cz, Liam.Howlett@...cle.com,
        adhemerval.zanella@...aro.org, oleg@...hat.com, avagin@...il.com,
        benjamin@...solutions.net, linux-kernel@...r.kernel.org,
        linux-hardening@...r.kernel.org, linux-mm@...ck.org,
        linux-kselftest@...r.kernel.org, jorgelo@...omium.org,
        sroettger@...gle.com, hch@....de, ojeda@...nel.org,
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        mpe@...erman.id.au, aleksandr.mikhalitsyn@...onical.com,
        mike.rapoport@...il.com
Subject: Re: [PATCH v8 7/7] selftest: test system mappings are sealed.


On Mon, Mar 03, 2025 at 05:09:21AM +0000, jeffxu@...omium.org wrote:
> From: Jeff Xu <jeffxu@...omium.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@...omium.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@...cle.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!

>  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
>