From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-vk0-f69.google.com (mail-vk0-f69.google.com [209.85.213.69]) by kanga.kvack.org (Postfix) with ESMTP id DB7616B0003 for ; Mon, 12 Feb 2018 18:43:58 -0500 (EST) Received: by mail-vk0-f69.google.com with SMTP id c17so10151343vke.1 for ; Mon, 12 Feb 2018 15:43:58 -0800 (PST) Received: from mail-sor-f65.google.com (mail-sor-f65.google.com. [209.85.220.65]) by mx.google.com with SMTPS id g88sor3416029uag.139.2018.02.12.15.43.57 for (Google Transport Security); Mon, 12 Feb 2018 15:43:57 -0800 (PST) MIME-Version: 1.0 In-Reply-To: <20180212165301.17933-6-igor.stoppa@huawei.com> References: <20180212165301.17933-1-igor.stoppa@huawei.com> <20180212165301.17933-6-igor.stoppa@huawei.com> From: Kees Cook Date: Mon, 12 Feb 2018 15:43:56 -0800 Message-ID: Subject: Re: [PATCH 5/6] Pmalloc: self-test Content-Type: text/plain; charset="UTF-8" Sender: owner-linux-mm@kvack.org List-ID: To: Igor Stoppa Cc: Matthew Wilcox , Randy Dunlap , Jonathan Corbet , Michal Hocko , Laura Abbott , Jerome Glisse , Christoph Hellwig , Christoph Lameter , linux-security-module , Linux-MM , LKML , Kernel Hardening On Mon, Feb 12, 2018 at 8:53 AM, Igor Stoppa wrote: > Add basic self-test functionality for pmalloc. > > Signed-off-by: Igor Stoppa > --- > mm/Kconfig | 9 ++++++++ > mm/Makefile | 1 + > mm/pmalloc-selftest.c | 64 +++++++++++++++++++++++++++++++++++++++++++++++++++ > mm/pmalloc-selftest.h | 24 +++++++++++++++++++ > mm/pmalloc.c | 2 ++ > 5 files changed, 100 insertions(+) > create mode 100644 mm/pmalloc-selftest.c > create mode 100644 mm/pmalloc-selftest.h > > diff --git a/mm/Kconfig b/mm/Kconfig > index be578fbdce6d..098aefef78b1 100644 > --- a/mm/Kconfig > +++ b/mm/Kconfig > @@ -766,3 +766,12 @@ config PROTECTABLE_MEMORY > depends on ARCH_HAS_SET_MEMORY > select GENERIC_ALLOCATOR > default y > + > +config PROTECTABLE_MEMORY_SELFTEST > + bool "Run self test for pmalloc memory allocator" > + depends on ARCH_HAS_SET_MEMORY > + select PROTECTABLE_MEMORY > + default n > + help > + Tries to verify that pmalloc works correctly and that the memory > + is effectively protected. > diff --git a/mm/Makefile b/mm/Makefile > index 959fdbdac118..f7bbbfde6967 100644 > --- a/mm/Makefile > +++ b/mm/Makefile > @@ -66,6 +66,7 @@ obj-$(CONFIG_SPARSEMEM_VMEMMAP) += sparse-vmemmap.o > obj-$(CONFIG_SLOB) += slob.o > obj-$(CONFIG_MMU_NOTIFIER) += mmu_notifier.o > obj-$(CONFIG_PROTECTABLE_MEMORY) += pmalloc.o > +obj-$(CONFIG_PROTECTABLE_MEMORY_SELFTEST) += pmalloc-selftest.o Nit: self-test modules are traditionally named "test_$thing.o" (outside of the tools/ directory). > obj-$(CONFIG_KSM) += ksm.o > obj-$(CONFIG_PAGE_POISONING) += page_poison.o > obj-$(CONFIG_SLAB) += slab.o > diff --git a/mm/pmalloc-selftest.c b/mm/pmalloc-selftest.c > new file mode 100644 > index 000000000000..97ba52d17f69 > --- /dev/null > +++ b/mm/pmalloc-selftest.c > @@ -0,0 +1,64 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * pmalloc-selftest.c > + * > + * (C) Copyright 2018 Huawei Technologies Co. Ltd. > + * Author: Igor Stoppa > + */ > + > +#include > +#include > + > +#include "pmalloc-selftest.h" > + > +#define SIZE_1 (PAGE_SIZE * 3) > +#define SIZE_2 1000 > + > +#define validate_alloc(expected, variable, size) \ > + pr_notice("must be " expected ": %s", \ > + is_pmalloc_object(variable, size) > 0 ? "ok" : "no") > + > +#define is_alloc_ok(variable, size) \ > + validate_alloc("ok", variable, size) > + > +#define is_alloc_no(variable, size) \ > + validate_alloc("no", variable, size) > + > +void pmalloc_selftest(void) > +{ > + struct gen_pool *pool_unprot; > + struct gen_pool *pool_prot; > + void *var_prot, *var_unprot, *var_vmall; > + > + pr_notice("pmalloc self-test"); > + pool_unprot = pmalloc_create_pool("unprotected", 0); > + pool_prot = pmalloc_create_pool("protected", 0); > + BUG_ON(!(pool_unprot && pool_prot)); > + > + var_unprot = pmalloc(pool_unprot, SIZE_1 - 1, GFP_KERNEL); > + var_prot = pmalloc(pool_prot, SIZE_1, GFP_KERNEL); > + *(int *)var_prot = 0; > + var_vmall = vmalloc(SIZE_2); > + is_alloc_ok(var_unprot, 10); > + is_alloc_ok(var_unprot, SIZE_1); > + is_alloc_ok(var_unprot, PAGE_SIZE); > + is_alloc_no(var_unprot, SIZE_1 + 1); > + is_alloc_no(var_vmall, 10); > + > + > + pfree(pool_unprot, var_unprot); > + vfree(var_vmall); > + > + pmalloc_protect_pool(pool_prot); > + > + /* > + * This will intentionally trigger a WARN because the pool being > + * destroyed is not protected, which is unusual and should happen > + * on error paths only, where probably other warnings are already > + * displayed. > + */ > + pmalloc_destroy_pool(pool_unprot); > + > + /* This must not cause WARNings */ > + pmalloc_destroy_pool(pool_prot); > +} I wonder if lkdtm should grow a test too, to validate the RO-ness of the allocations at the right time in API usage? Otherwise, yay! Selftests! -Kees > diff --git a/mm/pmalloc-selftest.h b/mm/pmalloc-selftest.h > new file mode 100644 > index 000000000000..58a5a0cbec14 > --- /dev/null > +++ b/mm/pmalloc-selftest.h > @@ -0,0 +1,24 @@ > +/* SPDX-License-Identifier: GPL-2.0 */ > +/* > + * pmalloc-selftest.h > + * > + * (C) Copyright 2018 Huawei Technologies Co. Ltd. > + * Author: Igor Stoppa > + */ > + > + > +#ifndef __MM_PMALLOC_SELFTEST_H > +#define __MM_PMALLOC_SELFTEST_H > + > + > +#ifdef CONFIG_PROTECTABLE_MEMORY_SELFTEST > + > +void pmalloc_selftest(void); > + > +#else > + > +static inline void pmalloc_selftest(void){}; > + > +#endif > + > +#endif > diff --git a/mm/pmalloc.c b/mm/pmalloc.c > index abddba90a9f6..eb445c574b19 100644 > --- a/mm/pmalloc.c > +++ b/mm/pmalloc.c > @@ -22,6 +22,7 @@ > #include > > #include > +#include "pmalloc-selftest.h" > /* > * pmalloc_data contains the data specific to a pmalloc pool, > * in a format compatible with the design of gen_alloc. > @@ -494,6 +495,7 @@ static int __init pmalloc_late_init(void) > } > } > mutex_unlock(&pmalloc_mutex); > + pmalloc_selftest(); > return 0; > } > late_initcall(pmalloc_late_init); > -- > 2.14.1 > -- Kees Cook Pixel Security -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org