From: Alexander Potapenko <glider@google.com>
To: 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>, 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>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
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>,
Mark Rutland <mark.rutland@arm.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: [PATCH v2 32/48] kmsan: disable strscpy() optimization under KMSAN
Date: Tue, 29 Mar 2022 14:40:01 +0200 [thread overview]
Message-ID: <20220329124017.737571-33-glider@google.com> (raw)
In-Reply-To: <20220329124017.737571-1-glider@google.com>
Disable the efficient 8-byte reading under KMSAN to avoid false positives.
Signed-off-by: Alexander Potapenko <glider@google.com>
---
Link: https://linux-review.googlesource.com/id/Iffd8336965e88fce915db2e6a9d6524422975f69
---
lib/string.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/lib/string.c b/lib/string.c
index 485777c9da832..4ece4c7e7831b 100644
--- a/lib/string.c
+++ b/lib/string.c
@@ -197,6 +197,14 @@ ssize_t strscpy(char *dest, const char *src, size_t count)
max = 0;
#endif
+ /*
+ * read_word_at_a_time() below may read uninitialized bytes after the
+ * trailing zero and use them in comparisons. Disable this optimization
+ * under KMSAN to prevent false positive reports.
+ */
+ if (IS_ENABLED(CONFIG_KMSAN))
+ max = 0;
+
while (max >= sizeof(unsigned long)) {
unsigned long c, data;
--
2.35.1.1021.g381101b075-goog
next prev parent reply other threads:[~2022-03-29 12:41 UTC|newest]
Thread overview: 57+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-29 12:39 [PATCH v2 00/48] Add KernelMemorySanitizer infrastructure Alexander Potapenko
2022-03-29 12:39 ` [PATCH v2 01/48] x86: add missing include to sparsemem.h Alexander Potapenko
2022-03-29 12:39 ` [PATCH v2 02/48] stackdepot: reserve 5 extra bits in depot_stack_handle_t Alexander Potapenko
2022-03-29 12:39 ` [PATCH v2 03/48] kasan: common: adapt to the new prototype of __stack_depot_save() Alexander Potapenko
2022-03-29 12:39 ` [PATCH v2 04/48] instrumented.h: allow instrumenting both sides of copy_from_user() Alexander Potapenko
2022-03-29 12:39 ` [PATCH v2 05/48] x86: asm: instrument usercopy in get_user() and __put_user_size() Alexander Potapenko
2022-03-29 12:39 ` [PATCH v2 06/48] asm-generic: instrument usercopy in cacheflush.h Alexander Potapenko
2022-03-29 12:39 ` [PATCH v2 07/48] kmsan: add ReST documentation Alexander Potapenko
2022-03-29 12:39 ` [PATCH v2 08/48] kmsan: introduce __no_sanitize_memory and __no_kmsan_checks Alexander Potapenko
2022-03-29 12:39 ` [PATCH v2 09/48] kmsan: mark noinstr as __no_sanitize_memory Alexander Potapenko
2022-03-29 12:39 ` [PATCH v2 10/48] x86: kmsan: pgtable: reduce vmalloc space Alexander Potapenko
2022-03-29 12:39 ` [PATCH v2 11/48] libnvdimm/pfn_dev: increase MAX_STRUCT_PAGE_SIZE Alexander Potapenko
2022-03-29 12:39 ` [PATCH v2 12/48] kcsan: clang: retire CONFIG_KCSAN_KCOV_BROKEN Alexander Potapenko
2022-03-30 6:00 ` Marco Elver
2022-03-29 12:39 ` [PATCH v2 13/48] kmsan: add KMSAN runtime core Alexander Potapenko
2022-03-30 8:58 ` Peter Zijlstra
2022-03-30 9:41 ` Peter Zijlstra
2022-04-04 14:39 ` Alexander Potapenko
2022-03-29 12:39 ` [PATCH v2 14/48] kmsan: implement kmsan_init(), initialize READ_ONCE_NOCHECK() Alexander Potapenko
2022-03-29 12:39 ` [PATCH v2 15/48] kmsan: disable instrumentation of unsupported common kernel code Alexander Potapenko
2022-03-29 12:39 ` [PATCH v2 16/48] MAINTAINERS: add entry for KMSAN Alexander Potapenko
2022-03-29 12:39 ` [PATCH v2 17/48] kmsan: mm: maintain KMSAN metadata for page operations Alexander Potapenko
2022-03-29 12:39 ` [PATCH v2 18/48] kmsan: mm: call KMSAN hooks from SLUB code Alexander Potapenko
2022-03-29 12:39 ` [PATCH v2 19/48] kmsan: handle task creation and exiting Alexander Potapenko
2022-03-29 12:39 ` [PATCH v2 20/48] kmsan: init: call KMSAN initialization routines Alexander Potapenko
2022-03-29 12:39 ` [PATCH v2 21/48] instrumented.h: add KMSAN support Alexander Potapenko
2022-03-29 12:39 ` [PATCH v2 22/48] kmsan: unpoison @tlb in arch_tlb_gather_mmu() Alexander Potapenko
2022-03-29 12:39 ` [PATCH v2 23/48] kmsan: add iomap support Alexander Potapenko
2022-03-29 12:39 ` [PATCH v2 24/48] Input: libps2: mark data received in __ps2_command() as initialized Alexander Potapenko
2022-03-29 12:39 ` [PATCH v2 25/48] kmsan: dma: unpoison DMA mappings Alexander Potapenko
2022-03-29 12:39 ` [PATCH v2 26/48] kmsan: virtio: check/unpoison scatterlist in vring_map_one_sg() Alexander Potapenko
2022-03-29 12:39 ` [PATCH v2 27/48] kmsan: handle memory sent to/from USB Alexander Potapenko
2022-03-29 12:39 ` [PATCH v2 28/48] kmsan: instrumentation.h: add instrumentation_begin_with_regs() Alexander Potapenko
2022-03-29 12:39 ` [PATCH v2 29/48] kmsan: entry: handle register passing from uninstrumented code Alexander Potapenko
2022-03-29 12:39 ` [PATCH v2 30/48] kmsan: add tests for KMSAN Alexander Potapenko
2022-03-29 12:40 ` [PATCH v2 31/48] kernel: kmsan: don't instrument stacktrace.c Alexander Potapenko
2022-04-04 14:56 ` Alexander Potapenko
2022-03-29 12:40 ` Alexander Potapenko [this message]
2022-03-29 12:40 ` [PATCH v2 33/48] crypto: kmsan: disable accelerated configs under KMSAN Alexander Potapenko
2022-03-29 12:40 ` [PATCH v2 34/48] kmsan: disable physical page merging in biovec Alexander Potapenko
2022-03-29 12:40 ` [PATCH v2 35/48] kmsan: block: skip bio block merging logic for KMSAN Alexander Potapenko
2022-03-29 12:40 ` [PATCH v2 36/48] kmsan: kcov: unpoison area->list in kcov_remote_area_put() Alexander Potapenko
2022-03-29 12:40 ` [PATCH v2 37/48] security: kmsan: fix interoperability with auto-initialization Alexander Potapenko
2022-03-29 12:40 ` [PATCH v2 38/48] objtool: kmsan: list KMSAN API functions as uaccess-safe Alexander Potapenko
2022-03-30 8:46 ` Peter Zijlstra
2022-04-14 15:30 ` Alexander Potapenko
2022-04-14 15:38 ` Peter Zijlstra
2022-03-29 12:40 ` [PATCH v2 39/48] x86: kmsan: make READ_ONCE_TASK_STACK() return initialized values Alexander Potapenko
2022-03-29 12:40 ` [PATCH v2 40/48] x86: kmsan: disable instrumentation of unsupported code Alexander Potapenko
2022-03-29 12:40 ` [PATCH v2 41/48] x86: kmsan: skip shadow checks in __switch_to() Alexander Potapenko
2022-03-29 12:40 ` [PATCH v2 42/48] x86: kmsan: handle open-coded assembly in lib/iomem.c Alexander Potapenko
2022-03-29 12:40 ` [PATCH v2 43/48] x86: kmsan: use __msan_ string functions where possible Alexander Potapenko
2022-03-29 12:40 ` [PATCH v2 44/48] x86: kmsan: sync metadata pages on page fault Alexander Potapenko
2022-03-29 12:40 ` [PATCH v2 45/48] x86: kasan: kmsan: support CONFIG_GENERIC_CSUM on x86, enable it for KASAN/KMSAN Alexander Potapenko
2022-03-29 12:40 ` [PATCH v2 46/48] x86: fs: kmsan: disable CONFIG_DCACHE_WORD_ACCESS Alexander Potapenko
2022-03-29 12:40 ` [PATCH v2 47/48] x86: kmsan: handle register passing from uninstrumented code Alexander Potapenko
2022-03-29 12:40 ` [PATCH v2 48/48] x86: kmsan: enable KMSAN builds for x86 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=20220329124017.737571-33-glider@google.com \
--to=glider@google.com \
--cc=akpm@linux-foundation.org \
--cc=andreyknvl@google.com \
--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=gor@linux.ibm.com \
--cc=gregkh@linuxfoundation.org \
--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=mark.rutland@arm.com \
--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 NNTP newsgroup(s).