From nobody Mon Feb 9 19:26:49 2026 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.15]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5F63D145674 for ; Tue, 12 Mar 2024 22:29:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.15 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1710282554; cv=none; b=b9iev4w30z8ied/BilL/erGzWaulC7OfuUqQYQJX5E6nk4ob5jsw7ysE7GfLm+0dV1pCevReL4RUw2lI+7sW1ClP8G5FumvPvai0/aaMjlCce8kSmZSscc1v9fxHJ/bDQgFMNapmWCKppjTFbNzqassIVMJJoFtfHq0Zh6BjbZg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1710282554; c=relaxed/simple; bh=9Kz1B1g9YBWVQVBA7u5n8sBfRhBddgPHEWEy/INdrdY=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=HIDaueI3VY54MGTDaicJCnFobKIMg0HKnwGJaPDoNiXldwlFZaOCv9sku8ekOnHJ0JL0v1yuGUVmb10bGcwgbO0JQLfAgpRBYNj0wxz9f24hghu6Q/mL3kNIZ+DiN4iUWRfk5ffTie1m/BJcxwzoUX5yUcgbAPx24GWFh5VMmqs= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com; spf=pass smtp.mailfrom=intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=e8ZO6C39; arc=none smtp.client-ip=192.198.163.15 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="e8ZO6C39" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1710282553; x=1741818553; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=9Kz1B1g9YBWVQVBA7u5n8sBfRhBddgPHEWEy/INdrdY=; b=e8ZO6C39lQATqSmUewTLf/q93OfAJeT8nyWFJx5ZM0q4yK4BtupB2wYu /q4HH50m397PQn1hreOnAYB04BTXrxAY2wTj6E0h9FYC1ggBfzjiGWBQD OFP7nISyj/OyMmMjo0kCAZrmKtnhri8ib5xlRlGdVYpf7+6RxqS5jDtq3 a0JzGcRfC/9gKAqC4gWGOlHkL/2FyREzjyEjRMGqAcYHf9A03cT7mfAhP 16indzBY7i3NC9H1144dQJ0orsk1KQK4/6eK9avIZSZnXKxG+x5WRCVG1 d5Qx4p/X2Czo3XFoDIHPLVXcFW82P4iTH5KPqTIMHmk/Cn3ykZssl14R8 A==; X-IronPort-AV: E=McAfee;i="6600,9927,11011"; a="5192091" X-IronPort-AV: E=Sophos;i="6.07,119,1708416000"; d="scan'208";a="5192091" Received: from orviesa004.jf.intel.com ([10.64.159.144]) by fmvoesa109.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 Mar 2024 15:29:05 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.07,119,1708416000"; d="scan'208";a="16356888" Received: from gargayus-mobl1.amr.corp.intel.com (HELO rpedgeco-desk4.intel.com) ([10.255.231.196]) by orviesa004-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 Mar 2024 15:29:05 -0700 From: Rick Edgecombe To: Liam.Howlett@oracle.com, akpm@linux-foundation.org, bp@alien8.de, broonie@kernel.org, dave.hansen@linux.intel.com, debug@rivosinc.com, hpa@zytor.com, keescook@chromium.org, kirill.shutemov@linux.intel.com, luto@kernel.org, mingo@redhat.com, peterz@infradead.org, tglx@linutronix.de, x86@kernel.org, christophe.leroy@csgroup.eu Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, rick.p.edgecombe@intel.com Subject: [PATCH v3 12/12] selftests/x86: Add placement guard gap test for shstk Date: Tue, 12 Mar 2024 15:28:43 -0700 Message-Id: <20240312222843.2505560-13-rick.p.edgecombe@intel.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20240312222843.2505560-1-rick.p.edgecombe@intel.com> References: <20240312222843.2505560-1-rick.p.edgecombe@intel.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" The existing shadow stack test for guard gaps just checks that new mappings are not placed in an existing mapping's guard gap. Add one that checks that new mappings are not placed such that preexisting mappings are in the new mappings guard gap. Signed-off-by: Rick Edgecombe --- .../testing/selftests/x86/test_shadow_stack.c | 67 +++++++++++++++++-- 1 file changed, 63 insertions(+), 4 deletions(-) diff --git a/tools/testing/selftests/x86/test_shadow_stack.c b/tools/testin= g/selftests/x86/test_shadow_stack.c index 757e6527f67e..ee909a7927f9 100644 --- a/tools/testing/selftests/x86/test_shadow_stack.c +++ b/tools/testing/selftests/x86/test_shadow_stack.c @@ -556,7 +556,7 @@ struct node { * looked at the shadow stack gaps. * 5. See if it landed in the gap. */ -int test_guard_gap(void) +int test_guard_gap_other_gaps(void) { void *free_area, *shstk, *test_map =3D (void *)0xFFFFFFFFFFFFFFFF; struct node *head =3D NULL, *cur; @@ -593,11 +593,64 @@ int test_guard_gap(void) if (shstk - test_map - PAGE_SIZE !=3D PAGE_SIZE) return 1; =20 - printf("[OK]\tGuard gap test\n"); + printf("[OK]\tGuard gap test, other mapping's gaps\n"); =20 return 0; } =20 +/* Tests respecting the guard gap of the mapping getting placed */ +int test_guard_gap_new_mappings_gaps(void) +{ + void *free_area, *shstk_start, *test_map =3D (void *)0xFFFFFFFFFFFFFFFF; + struct node *head =3D NULL, *cur; + int ret =3D 0; + + free_area =3D mmap(0, PAGE_SIZE * 4, PROT_READ | PROT_WRITE, + MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); + munmap(free_area, PAGE_SIZE * 4); + + /* Test letting map_shadow_stack find a free space */ + shstk_start =3D mmap(free_area, PAGE_SIZE, PROT_READ | PROT_WRITE, + MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); + if (shstk_start =3D=3D MAP_FAILED || shstk_start !=3D free_area) + return 1; + + while (test_map > shstk_start) { + test_map =3D (void *)syscall(__NR_map_shadow_stack, 0, PAGE_SIZE, 0); + if (test_map =3D=3D MAP_FAILED) { + printf("[INFO]\tmap_shadow_stack MAP_FAILED\n"); + ret =3D 1; + break; + } + + cur =3D malloc(sizeof(*cur)); + cur->mapping =3D test_map; + + cur->next =3D head; + head =3D cur; + + if (test_map =3D=3D free_area + PAGE_SIZE) { + printf("[INFO]\tNew mapping has other mapping in guard gap!\n"); + ret =3D 1; + break; + } + } + + while (head) { + cur =3D head; + head =3D cur->next; + munmap(cur->mapping, PAGE_SIZE); + free(cur); + } + + munmap(shstk_start, PAGE_SIZE); + + if (!ret) + printf("[OK]\tGuard gap test, placement mapping's gaps\n"); + + return ret; +} + /* * Too complicated to pull it out of the 32 bit header, but also get the * 64 bit one needed above. Just define a copy here. @@ -850,9 +903,15 @@ int main(int argc, char *argv[]) goto out; } =20 - if (test_guard_gap()) { + if (test_guard_gap_other_gaps()) { ret =3D 1; - printf("[FAIL]\tGuard gap test\n"); + printf("[FAIL]\tGuard gap test, other mappings' gaps\n"); + goto out; + } + + if (test_guard_gap_new_mappings_gaps()) { + ret =3D 1; + printf("[FAIL]\tGuard gap test, placement mapping's gaps\n"); goto out; } =20 --=20 2.34.1