From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: Alexander Potapenko <glider@google.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>,
Andrew Morton <akpm@linux-foundation.org>,
Andrey Konovalov <andreyknvl@google.com>,
Andy Lutomirski <luto@kernel.org>,
Ard Biesheuvel <ard.biesheuvel@linaro.org>,
Arnd Bergmann <arnd@arndb.de>, Borislav Petkov <bp@alien8.de>,
Christoph Hellwig <hch@lst.de>, Christoph Lameter <cl@linux.com>,
David Rientjes <rientjes@google.com>,
Dmitry Vyukov <dvyukov@google.com>,
Eric Dumazet <edumazet@google.com>,
Herbert Xu <herbert@gondor.apana.org.au>,
Ilya Leoshkevich <iii@linux.ibm.com>,
Ingo Molnar <mingo@redhat.com>, Jens Axboe <axboe@kernel.dk>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
Kees Cook <keescook@chromium.org>, Marco Elver <elver@google.com>,
Matthew Wilcox <willy@infradead.org>,
"Michael S. Tsirkin" <mst@redhat.com>,
Pekka Enberg <penberg@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Petr Mladek <pmladek@suse.com>,
Steven Rostedt <rostedt@goodmis.org>,
Thomas Gleixner <tglx@linutronix.de>,
Vasily Gorbik <gor@linux.ibm.com>,
Vegard Nossum <vegard.nossum@oracle.com>,
Vlastimil Babka <vbabka@suse.cz>,
linux-mm@kvack.org, linux-arch@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 41/43] security: kmsan: fix interoperability with auto-initialization
Date: Tue, 14 Dec 2021 17:38:06 +0100 [thread overview]
Message-ID: <YbjIbpFRqMac/X8s@kroah.com> (raw)
In-Reply-To: <20211214162050.660953-42-glider@google.com>
On Tue, Dec 14, 2021 at 05:20:48PM +0100, Alexander Potapenko wrote:
> Heap and stack initialization is great, but not when we are trying
> uses of uninitialized memory. When the kernel is built with KMSAN,
> having kernel memory initialization enabled may introduce false
> negatives.
>
> We disable CONFIG_INIT_STACK_ALL_PATTERN and CONFIG_INIT_STACK_ALL_ZERO
> under CONFIG_KMSAN, making it impossible to auto-initialize stack
> variables in KMSAN builds. We also disable CONFIG_INIT_ON_ALLOC_DEFAULT_ON
> and CONFIG_INIT_ON_FREE_DEFAULT_ON to prevent accidental use of heap
> auto-initialization.
>
> We however still let the users enable heap auto-initialization at
> boot-time (by setting init_on_alloc=1 or init_on_free=1), in which case
> a warning is printed.
>
> Signed-off-by: Alexander Potapenko <glider@google.com>
> ---
> Link: https://linux-review.googlesource.com/id/I86608dd867018683a14ae1870f1928ad925f42e9
> ---
> mm/page_alloc.c | 4 ++++
> security/Kconfig.hardening | 4 ++++
> 2 files changed, 8 insertions(+)
>
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index fa8029b714a81..4218dea0c76a2 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -855,6 +855,10 @@ void init_mem_debugging_and_hardening(void)
> else
> static_branch_disable(&init_on_free);
>
> + if (IS_ENABLED(CONFIG_KMSAN) &&
> + (_init_on_alloc_enabled_early || _init_on_free_enabled_early))
> + pr_info("mem auto-init: please make sure init_on_alloc and init_on_free are disabled when running KMSAN\n");
> +
> #ifdef CONFIG_DEBUG_PAGEALLOC
> if (!debug_pagealloc_enabled())
> return;
> diff --git a/security/Kconfig.hardening b/security/Kconfig.hardening
> index d051f8ceefddd..bd13a46024457 100644
> --- a/security/Kconfig.hardening
> +++ b/security/Kconfig.hardening
> @@ -106,6 +106,7 @@ choice
> config INIT_STACK_ALL_PATTERN
> bool "pattern-init everything (strongest)"
> depends on CC_HAS_AUTO_VAR_INIT_PATTERN
> + depends on !KMSAN
> help
> Initializes everything on the stack (including padding)
> with a specific debug value. This is intended to eliminate
> @@ -124,6 +125,7 @@ choice
> config INIT_STACK_ALL_ZERO
> bool "zero-init everything (strongest and safest)"
> depends on CC_HAS_AUTO_VAR_INIT_ZERO
> + depends on !KMSAN
So this means KMSAN is a developer debugging feature only and should
never be turned on on a real device/server that has users?
thanks,
greg k-h
next prev parent reply other threads:[~2021-12-14 16:38 UTC|newest]
Thread overview: 75+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-14 16:20 [PATCH 00/43] Add KernelMemorySanitizer infrastructure Alexander Potapenko
2021-12-14 16:20 ` [PATCH 01/43] arch/x86: add missing include to sparsemem.h Alexander Potapenko
2021-12-14 16:20 ` [PATCH 02/43] stackdepot: reserve 5 extra bits in depot_stack_handle_t Alexander Potapenko
2021-12-14 16:20 ` [PATCH 03/43] kasan: common: adapt to the new prototype of __stack_depot_save() Alexander Potapenko
2021-12-14 16:20 ` [PATCH 04/43] instrumented.h: allow instrumenting both sides of copy_from_user() Alexander Potapenko
2021-12-14 16:20 ` [PATCH 05/43] asm: x86: instrument usercopy in get_user() and __put_user_size() Alexander Potapenko
2021-12-14 16:20 ` [PATCH 06/43] asm-generic: instrument usercopy in cacheflush.h Alexander Potapenko
2021-12-14 16:20 ` [PATCH 07/43] compiler_attributes.h: add __disable_sanitizer_instrumentation Alexander Potapenko
2021-12-15 13:24 ` Mark Rutland
2021-12-15 13:33 ` Marco Elver
2021-12-14 16:20 ` [PATCH 08/43] kmsan: add ReST documentation Alexander Potapenko
2021-12-14 16:20 ` [PATCH 09/43] kmsan: introduce __no_sanitize_memory and __no_kmsan_checks Alexander Potapenko
2021-12-15 13:27 ` Mark Rutland
2021-12-14 16:20 ` [PATCH 10/43] kmsan: pgtable: reduce vmalloc space Alexander Potapenko
2021-12-15 13:36 ` Mark Rutland
2022-03-18 14:14 ` Alexander Potapenko
2021-12-14 16:20 ` [PATCH 11/43] libnvdimm/pfn_dev: increase MAX_STRUCT_PAGE_SIZE Alexander Potapenko
2021-12-14 16:20 ` [PATCH 12/43] kcsan: clang: retire CONFIG_KCSAN_KCOV_BROKEN Alexander Potapenko
2021-12-15 13:33 ` Mark Rutland
2021-12-15 13:39 ` Marco Elver
2021-12-15 14:43 ` Mark Rutland
2022-03-18 14:34 ` Alexander Potapenko
2021-12-14 16:20 ` [PATCH 13/43] kmsan: add KMSAN runtime core Alexander Potapenko
2021-12-14 16:34 ` Greg Kroah-Hartman
2021-12-16 10:33 ` Alexander Potapenko
2021-12-17 16:22 ` Greg Kroah-Hartman
2022-03-21 14:12 ` Alexander Potapenko
[not found] ` <CACT4Y+Y_torRwzh0eDMn+pJh=YT26hGrAPA499WqN1dV+4bDHA@mail.gmail.com>
2022-03-21 13:17 ` Alexander Potapenko
2021-12-14 16:20 ` [PATCH 14/43] MAINTAINERS: add entry for KMSAN Alexander Potapenko
2021-12-14 16:20 ` [PATCH 15/43] kmsan: mm: maintain KMSAN metadata for page operations Alexander Potapenko
2021-12-14 16:20 ` [PATCH 16/43] kmsan: mm: call KMSAN hooks from SLUB code Alexander Potapenko
2022-01-07 17:22 ` Vlastimil Babka
2022-03-25 13:15 ` Alexander Potapenko
2021-12-14 16:20 ` [PATCH 17/43] kmsan: handle task creation and exiting Alexander Potapenko
2021-12-14 16:20 ` [PATCH 18/43] kmsan: unpoison @tlb in arch_tlb_gather_mmu() Alexander Potapenko
2021-12-14 16:20 ` [PATCH 19/43] kmsan: init: call KMSAN initialization routines Alexander Potapenko
2021-12-14 16:20 ` [PATCH 20/43] instrumented.h: add KMSAN support Alexander Potapenko
2021-12-14 16:20 ` [PATCH 21/43] kmsan: mark noinstr as __no_sanitize_memory Alexander Potapenko
2021-12-15 13:49 ` Mark Rutland
2021-12-14 16:20 ` [PATCH 22/43] kmsan: initialize the output of READ_ONCE_NOCHECK() Alexander Potapenko
2021-12-14 16:20 ` [PATCH 23/43] kmsan: make READ_ONCE_TASK_STACK() return initialized values Alexander Potapenko
2021-12-14 16:20 ` [PATCH 24/43] kmsan: disable KMSAN instrumentation for certain kernel parts Alexander Potapenko
2021-12-15 13:53 ` Mark Rutland
2021-12-14 16:20 ` [PATCH 25/43] kmsan: skip shadow checks in files doing context switches Alexander Potapenko
2021-12-15 14:13 ` Mark Rutland
2021-12-15 16:28 ` Alexander Potapenko
2021-12-15 17:22 ` Mark Rutland
2021-12-14 16:20 ` [PATCH 26/43] kmsan: virtio: check/unpoison scatterlist in vring_map_one_sg() Alexander Potapenko
2022-01-06 12:46 ` Michael S. Tsirkin
2021-12-14 16:20 ` [PATCH 27/43] x86: kmsan: add iomem support Alexander Potapenko
2021-12-14 16:20 ` [PATCH 28/43] kmsan: dma: unpoison DMA mappings Alexander Potapenko
2021-12-14 16:20 ` [PATCH 29/43] kmsan: handle memory sent to/from USB Alexander Potapenko
2021-12-14 16:20 ` [PATCH 30/43] kmsan: add tests for KMSAN Alexander Potapenko
2021-12-14 16:20 ` [PATCH 31/43] kmsan: disable strscpy() optimization under KMSAN Alexander Potapenko
2021-12-14 16:20 ` [PATCH 32/43] crypto: kmsan: disable accelerated configs " Alexander Potapenko
2021-12-14 16:20 ` [PATCH 33/43] kmsan: disable physical page merging in biovec Alexander Potapenko
2021-12-15 14:17 ` Mark Rutland
2021-12-15 16:30 ` Alexander Potapenko
2021-12-14 16:20 ` [PATCH 34/43] kmsan: block: skip bio block merging logic for KMSAN Alexander Potapenko
2021-12-14 16:20 ` [PATCH 35/43] x86: kmsan: use __msan_ string functions where possible Alexander Potapenko
2021-12-14 16:20 ` [PATCH 36/43] x86: kmsan: sync metadata pages on page fault Alexander Potapenko
2021-12-14 16:20 ` [PATCH 37/43] x86: kasan: kmsan: support CONFIG_GENERIC_CSUM on x86, enable it for KASAN/KMSAN Alexander Potapenko
2021-12-14 16:20 ` [PATCH 38/43] x86: fs: kmsan: disable CONFIG_DCACHE_WORD_ACCESS Alexander Potapenko
2021-12-14 16:20 ` [PATCH 39/43] x86: kmsan: handle register passing from uninstrumented code Alexander Potapenko
2021-12-17 21:51 ` Thomas Gleixner
2021-12-20 14:35 ` Alexander Potapenko
2021-12-14 16:20 ` [PATCH 40/43] kmsan: kcov: unpoison area->list in kcov_remote_area_put() Alexander Potapenko
2021-12-14 16:20 ` [PATCH 41/43] security: kmsan: fix interoperability with auto-initialization Alexander Potapenko
2021-12-14 16:38 ` Greg Kroah-Hartman [this message]
2021-12-14 17:00 ` Alexander Potapenko
2021-12-14 17:33 ` Greg Kroah-Hartman
2021-12-14 16:20 ` [PATCH 42/43] objtool: kmsan: list KMSAN API functions as uaccess-safe Alexander Potapenko
2021-12-14 16:20 ` [PATCH 43/43] x86: kmsan: enable KMSAN builds for x86 Alexander Potapenko
2021-12-14 16:36 ` [PATCH 00/43] Add KernelMemorySanitizer infrastructure Greg Kroah-Hartman
2021-12-16 10:12 ` Alexander Potapenko
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=YbjIbpFRqMac/X8s@kroah.com \
--to=gregkh@linuxfoundation.org \
--cc=akpm@linux-foundation.org \
--cc=andreyknvl@google.com \
--cc=ard.biesheuvel@linaro.org \
--cc=arnd@arndb.de \
--cc=axboe@kernel.dk \
--cc=bp@alien8.de \
--cc=cl@linux.com \
--cc=dvyukov@google.com \
--cc=edumazet@google.com \
--cc=elver@google.com \
--cc=glider@google.com \
--cc=gor@linux.ibm.com \
--cc=hch@lst.de \
--cc=herbert@gondor.apana.org.au \
--cc=iamjoonsoo.kim@lge.com \
--cc=iii@linux.ibm.com \
--cc=keescook@chromium.org \
--cc=linux-arch@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=luto@kernel.org \
--cc=mingo@redhat.com \
--cc=mst@redhat.com \
--cc=penberg@kernel.org \
--cc=peterz@infradead.org \
--cc=pmladek@suse.com \
--cc=rientjes@google.com \
--cc=rostedt@goodmis.org \
--cc=tglx@linutronix.de \
--cc=vbabka@suse.cz \
--cc=vegard.nossum@oracle.com \
--cc=viro@zeniv.linux.org.uk \
--cc=willy@infradead.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).