From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 83716C77B7C for ; Thu, 4 May 2023 20:30:02 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id D2FDF6B0075; Thu, 4 May 2023 16:30:01 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id CE07A6B0078; Thu, 4 May 2023 16:30:01 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id BA752900002; Thu, 4 May 2023 16:30:01 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from mail.ispras.ru (mail.ispras.ru [83.149.199.84]) by kanga.kvack.org (Postfix) with ESMTP id 755A06B0075 for ; Thu, 4 May 2023 16:30:01 -0400 (EDT) Received: from mail.ispras.ru (unknown [83.149.199.84]) by mail.ispras.ru (Postfix) with ESMTPSA id A34C640755D7; Thu, 4 May 2023 20:29:58 +0000 (UTC) DKIM-Filter: OpenDKIM Filter v2.11.0 mail.ispras.ru A34C640755D7 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ispras.ru; s=default; t=1683232198; bh=kDImfhQO/qI/3ff441daw4emlLBdlJ25y15oGU/S5Rk=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=e+RFPFYosHbunosEgZSAtO4gQnjK8cOTlpUe/5ro/wgIOBQ0VYifbz8821Aydfznj KJVFZq7mNQz4m0fkikY83Ghvyw+gCRD96lmI4GP9XTdkH7kJp50lTO5Y6b8tLp9P0J mz8PN9GDgATrUsp63aoHEwnlf/KC8F+fXr4Ibr14= MIME-Version: 1.0 Date: Thu, 04 May 2023 23:29:58 +0300 From: Alexey Izbyshev To: Florent Revest Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, akpm@linux-foundation.org, catalin.marinas@arm.com, anshuman.khandual@arm.com, joey.gouly@arm.com, mhocko@suse.com, keescook@chromium.org, david@redhat.com, peterx@redhat.com, nd@arm.com, broonie@kernel.org, szabolcs.nagy@arm.com Subject: Re: [PATCH 4/4] kselftest: vm: Add tests for no-inherit memory-deny-write-execute In-Reply-To: <20230504170942.822147-5-revest@chromium.org> References: <20230504170942.822147-1-revest@chromium.org> <20230504170942.822147-5-revest@chromium.org> User-Agent: Roundcube Webmail/1.4.4 Message-ID: <66900d0ad42797a55259061f757beece@ispras.ru> X-Sender: izbyshev@ispras.ru Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 2023-05-04 20:09, Florent Revest wrote: > Add some tests to cover the new PR_MDWE_NO_INHERIT flag of the > PR_SET_MDWE prctl. > > Signed-off-by: Florent Revest > --- > tools/testing/selftests/mm/mdwe_test.c | 95 ++++++++++++++++++++++++-- > 1 file changed, 89 insertions(+), 6 deletions(-) > > diff --git a/tools/testing/selftests/mm/mdwe_test.c > b/tools/testing/selftests/mm/mdwe_test.c > index 91aa9c3099e7..9f08ed1b99ae 100644 > --- a/tools/testing/selftests/mm/mdwe_test.c > +++ b/tools/testing/selftests/mm/mdwe_test.c > @@ -22,6 +22,8 @@ > > TEST(prctl_flags) > { > + EXPECT_LT(prctl(PR_SET_MDWE, PR_MDWE_NO_INHERIT, 0L, 0L, 7L), 0); > + PR_MDWE_NO_INHERIT is defined to an int constant, so passing it to prctl() without a cast to long or similar may produce wrong code on 64-bit targets (ABIs typically don't require the compiler to clear the upper 32 bits of a 64-bit register when passing a 32-bit argument, so va_arg(arg, unsigned long) in prctl() implementation might get junk). Arguably, defining PR_MDWE_* to plain int constants is a bug, or at least a footgun for users of uapi headers. Thanks, Alexey > EXPECT_LT(prctl(PR_SET_MDWE, 7L, 0L, 0L, 0L), 0); > EXPECT_LT(prctl(PR_SET_MDWE, 0L, 7L, 0L, 0L), 0); > EXPECT_LT(prctl(PR_SET_MDWE, 0L, 0L, 7L, 0L), 0); > @@ -33,6 +35,66 @@ TEST(prctl_flags) > EXPECT_LT(prctl(PR_GET_MDWE, 0L, 0L, 0L, 7L), 0); > } > > +FIXTURE(consecutive_prctl_flags) {}; > +FIXTURE_SETUP(consecutive_prctl_flags) {} > +FIXTURE_TEARDOWN(consecutive_prctl_flags) {} > + > +FIXTURE_VARIANT(consecutive_prctl_flags) > +{ > + unsigned long first_flags; > + unsigned long second_flags; > + bool should_work; > +}; > + > +FIXTURE_VARIANT_ADD(consecutive_prctl_flags, same) > +{ > + .first_flags = PR_MDWE_REFUSE_EXEC_GAIN, > + .second_flags = PR_MDWE_REFUSE_EXEC_GAIN, > + .should_work = true, > +}; > + > +FIXTURE_VARIANT_ADD(consecutive_prctl_flags, cant_disable_mdwe) > +{ > + .first_flags = PR_MDWE_REFUSE_EXEC_GAIN, > + .second_flags = 0, > + .should_work = false, > +}; > + > +FIXTURE_VARIANT_ADD(consecutive_prctl_flags, > cant_disable_mdwe_no_inherit) > +{ > + .first_flags = PR_MDWE_REFUSE_EXEC_GAIN | PR_MDWE_NO_INHERIT, > + .second_flags = 0, > + .should_work = false, > +}; > + > +FIXTURE_VARIANT_ADD(consecutive_prctl_flags, can_lower_privileges) > +{ > + .first_flags = PR_MDWE_REFUSE_EXEC_GAIN | PR_MDWE_NO_INHERIT, > + .second_flags = PR_MDWE_REFUSE_EXEC_GAIN, > + .should_work = true, > +}; > + > +FIXTURE_VARIANT_ADD(consecutive_prctl_flags, cant_gain_privileges) > +{ > + .first_flags = PR_MDWE_REFUSE_EXEC_GAIN, > + .second_flags = PR_MDWE_REFUSE_EXEC_GAIN | PR_MDWE_NO_INHERIT, > + .should_work = false, > +}; > + > +TEST_F(consecutive_prctl_flags, two_prctls) > +{ > + int ret; > + > + EXPECT_EQ(prctl(PR_SET_MDWE, variant->first_flags, 0L, 0L, 0L), 0); > + > + ret = prctl(PR_SET_MDWE, variant->second_flags, 0L, 0L, 0L); > + if (variant->should_work) { > + EXPECT_EQ(ret, 0); > + } else { > + EXPECT_NE(ret, 0); > + } > +} > + > FIXTURE(mdwe) > { > void *p; > @@ -45,28 +107,45 @@ FIXTURE_VARIANT(mdwe) > { > bool enabled; > bool forked; > + bool inherit; > }; > > FIXTURE_VARIANT_ADD(mdwe, stock) > { > .enabled = false, > .forked = false, > + .inherit = false, > }; > > FIXTURE_VARIANT_ADD(mdwe, enabled) > { > .enabled = true, > .forked = false, > + .inherit = true, > }; > > -FIXTURE_VARIANT_ADD(mdwe, forked) > +FIXTURE_VARIANT_ADD(mdwe, inherited) > { > .enabled = true, > .forked = true, > + .inherit = true, > }; > > +FIXTURE_VARIANT_ADD(mdwe, not_inherited) > +{ > + .enabled = true, > + .forked = true, > + .inherit = false, > +}; > + > +static bool executable_map_should_fail(const FIXTURE_VARIANT(mdwe) > *variant) > +{ > + return variant->enabled && (!variant->forked || variant->inherit); > +} > + > FIXTURE_SETUP(mdwe) > { > + unsigned long mdwe_flags; > int ret, status; > > self->p = NULL; > @@ -76,13 +155,17 @@ FIXTURE_SETUP(mdwe) > if (!variant->enabled) > return; > > - ret = prctl(PR_SET_MDWE, PR_MDWE_REFUSE_EXEC_GAIN, 0L, 0L, 0L); > + mdwe_flags = PR_MDWE_REFUSE_EXEC_GAIN; > + if (!variant->inherit) > + mdwe_flags |= PR_MDWE_NO_INHERIT; > + > + ret = prctl(PR_SET_MDWE, mdwe_flags, 0L, 0L, 0L); > ASSERT_EQ(ret, 0) { > TH_LOG("PR_SET_MDWE failed or unsupported"); > } > > ret = prctl(PR_GET_MDWE, 0L, 0L, 0L, 0L); > - ASSERT_EQ(ret, 1); > + ASSERT_EQ(ret, mdwe_flags); > > if (variant->forked) { > self->pid = fork(); > @@ -113,7 +196,7 @@ TEST_F(mdwe, mmap_READ_EXEC) > TEST_F(mdwe, mmap_WRITE_EXEC) > { > self->p = mmap(NULL, self->size, PROT_WRITE | PROT_EXEC, self->flags, > 0, 0); > - if (variant->enabled) { > + if (executable_map_should_fail(variant)) { > EXPECT_EQ(self->p, MAP_FAILED); > } else { > EXPECT_NE(self->p, MAP_FAILED); > @@ -139,7 +222,7 @@ TEST_F(mdwe, mprotect_add_EXEC) > ASSERT_NE(self->p, MAP_FAILED); > > ret = mprotect(self->p, self->size, PROT_READ | PROT_EXEC); > - if (variant->enabled) { > + if (executable_map_should_fail(variant)) { > EXPECT_LT(ret, 0); > } else { > EXPECT_EQ(ret, 0); > @@ -154,7 +237,7 @@ TEST_F(mdwe, mprotect_WRITE_EXEC) > ASSERT_NE(self->p, MAP_FAILED); > > ret = mprotect(self->p, self->size, PROT_WRITE | PROT_EXEC); > - if (variant->enabled) { > + if (executable_map_should_fail(variant)) { > EXPECT_LT(ret, 0); > } else { > EXPECT_EQ(ret, 0);