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 X-Spam-Level: X-Spam-Status: No, score=-11.4 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT,USER_IN_DEF_DKIM_WL autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B4ECBC43603 for ; Fri, 20 Dec 2019 18:50:03 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 5B411206DA for ; Fri, 20 Dec 2019 18:50:03 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="LyU11/b4" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5B411206DA Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 00B7A8E01A3; Fri, 20 Dec 2019 13:50:03 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id EFEA78E019D; Fri, 20 Dec 2019 13:50:02 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id E177D8E01A3; Fri, 20 Dec 2019 13:50:02 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0213.hostedemail.com [216.40.44.213]) by kanga.kvack.org (Postfix) with ESMTP id C77A78E019D for ; Fri, 20 Dec 2019 13:50:02 -0500 (EST) Received: from smtpin07.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with SMTP id 67C1A5DF0 for ; Fri, 20 Dec 2019 18:50:02 +0000 (UTC) X-FDA: 76286409444.07.stew34_74ac04ee15417 X-HE-Tag: stew34_74ac04ee15417 X-Filterd-Recvd-Size: 18525 Received: from mail-qt1-f202.google.com (mail-qt1-f202.google.com [209.85.160.202]) by imf31.hostedemail.com (Postfix) with ESMTP for ; Fri, 20 Dec 2019 18:50:01 +0000 (UTC) Received: by mail-qt1-f202.google.com with SMTP id l1so6496656qtp.21 for ; Fri, 20 Dec 2019 10:50:01 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:message-id:mime-version:subject:from:to:cc; bh=AZW+OmIBOaOpoOvsmGMOrGmbgApsx36ws5tOhRgrozY=; b=LyU11/b468YoHva63+IC+oTaXVN81UJhiqZgYDHY+RW3FD0IWesZ9jc6p/5iDJeeIY ESdGEilBzeKdOWbQkx7Pe/TNFf6wf6OqmpNx/wreQTJ+atig8SELThMuQcx0pHolUD1l Z3FzEZRbyZL8qA4Fm7W8WepHJV9JGKYnilPWg1xpGsELg43FaRAepowewEChxgrWNOyO /oqsIKBiC9NRHjbppuYwkWg4cMzXUWejfz6O1CPO0zjExp76wpOXapXhWu32Y6aHbTo4 VEAPGwo0DL4ZodVHCOZwAJauHiRvDOB2Zkmho/Wbf+SnBTkxAQTXN7W2HxJS1tDNQC5H ULxw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:message-id:mime-version:subject:from:to:cc; bh=AZW+OmIBOaOpoOvsmGMOrGmbgApsx36ws5tOhRgrozY=; b=Dps+WcuPblxBCJWLdNBa1Tz6KjPlzNwXyvVbVoU0HxLbQLGaKvaOcLCV1oDUan5rN1 DTL4bpskUkTbfnYiInCqZ/a4TH0SvEfj/S4yQOYpiJQscbC7McOvmkNT3mtlmUYlkd7N QbMDEwH7LOVkEa590lmD19x5nruj8edlEN5TJOF1V2PBHnDBBNx4LZTXEydCap8VTljQ BYPtFP9nAXZnIwpHYvPHoCZMiaM+bgkm/kqIzzWuc2zciQwovSOBuOgEhDdOCkzFivmL jhYbHeLdZu0KvCUrUcBHlPEDg8Ttzx6hIMLRmQZttOjIOcOps4CqcO2wWekg6pjeAXrA ysww== X-Gm-Message-State: APjAAAWtmj8EXLjOauvDNLhmUBma1amRdupr6Af3Sjvcho87RNxP9bnz IVMZeDPla43C6DihfIy2CdrrWvnbMUQ= X-Google-Smtp-Source: APXvYqw6n+iDYXBa2aqztkXS5c4b8ZpptiHpEOS5I6w2m0RsjCRbaAvuj5mVakuLQEUUXHkhtqJPAUVSbtU= X-Received: by 2002:a05:6214:42c:: with SMTP id a12mr13403617qvy.172.1576867800696; Fri, 20 Dec 2019 10:50:00 -0800 (PST) Date: Fri, 20 Dec 2019 19:49:13 +0100 Message-Id: <20191220184955.223741-1-glider@google.com> Mime-Version: 1.0 X-Mailer: git-send-email 2.24.1.735.g03f4e72817-goog Subject: [PATCH RFC v4 00/42] Add KernelMemorySanitizer infrastructure From: glider@google.com To: Alexander Viro , Andreas Dilger , Andrew Morton , Andrey Konovalov , Andrey Ryabinin , Andy Lutomirski , Ard Biesheuvel , Arnd Bergmann , Christoph Hellwig , Christoph Hellwig , "Darrick J. Wong" , "David S. Miller" , Dmitry Torokhov , Dmitry Vyukov , Eric Biggers , Eric Dumazet , Eric Van Hensbergen , Greg Kroah-Hartman , Harry Wentland , Herbert Xu , Ilya Leoshkevich , Ingo Molnar , Jason Wang , Jens Axboe , Marek Szyprowski , Marco Elver , Mark Rutland , "Martin K. Petersen" , Martin Schwidefsky , Matthew Wilcox , "Michael S. Tsirkin" , Michal Simek , Petr Mladek , Qian Cai , Randy Dunlap , Robin Murphy , Sergey Senozhatsky , Steven Rostedt , Takashi Iwai , "Theodore Ts'o" , Thomas Gleixner , Vasily Gorbik , Vegard Nossum , Wolfram Sang , linux-mm@kvack.org Cc: glider@google.com, mhocko@suse.com Content-Type: text/plain; charset="UTF-8" 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: KernelMemorySanitizer (KMSAN) is a detector of errors related to uses of uninitialized memory. It relies on compile-time Clang instrumentation (similar to MSan in the userspace: https://clang.llvm.org/docs/MemorySanitizer.html) and tracks the state of every bit of kernel memory, being able to report an error if uninitialized value is used in a condition, dereferenced or copied to userspace, USB or network. KMSAN has reported more than 200 bugs in the past two years, most of them with the help of syzkaller (http://syzkaller.appspot.com). The proposed patchset contains KMSAN runtime implementation together with small changes to other subsystems needed to make KMSAN work. The latter changes fall into several categories: - nice-to-have features that are independent from KMSAN but simplify its implementation (stackdepot changes, CONFIG_GENERIC_CSUM etc.); - Kconfig changes that prohibit options incompatible with KMSAN; - calls to KMSAN runtime functions that help KMSAN do the bookkeeping (e.g. tell it to allocate, copy or delete the metadata); - calls to KMSAN runtime functions that tell KMSAN to check memory escaping the kernel for uninitialized values. These are required to increase the number of true positive error reports; - calls to runtime functions that tell KMSAN to ignore certain memory ranges to avoid false negative reports. Most certainly there can be better ways to deal with every such report. This patchset allows one to boot and run a defconfig+KMSAN kernel on a QEMU without known major false positives. It however doesn't guarantee there are no false positives in drivers of certain devices or less tested subsystems, although KMSAN is actively tested on syzbot with quite a rich config. One may find it handy to review these patches in Gerrit: https://linux-review.googlesource.com/c/linux/kernel/git/torvalds/linux/+/1081 I've ensured the Change-Id: tags stay away from commit descriptions. The patchset was generated relative to Linux v5.5-rc1. Several points worth a separate discussion: 1. Right now KMSAN assumes that contiguous physical pages cannot be accessed as such, unless they were allocated together by a single alloc_pages() call. Some kernel code however does so, which may break under KMSAN. Two possible solutions to this problem are: A. Allocate shadow and origin pages at fixed offset from the kernel page. This is what we already do for vmalloc, but not for page_alloc(), as it turned out to be quite hard. Ideas on how to implement this approach are still welcome, because it'll simplify the rest of the KMSAN runtime a lot. B. Make all accesses touching non-contiguous pages access dummy shadow pages instead, so that such accesses don't produce any uninitialized values. This is quite controversial, as it may prevent true positives from being reported. 2. checkpatch.pl complains a lot about the use of BUG_ON in KMSAN source. I don't have a strong opinion on this, but KMSAN is a debugging tool, so any runtime invariant violation in it renders the tool useless. Therefore it doesn't make much sense to not terminate after a bug in KMSAN. 3. objtool complains a lot about calls to KMSAN runtime with UACCESS enabled. None of these functions is expected to touch userspace memory, but they can be called in the uaccess context, as the compiler adds them to every memory access. Turns out it's not enough to just whitelist KMSAN interface functions in tools/objtool/check.c, as they are viral: after whitelisting them I get warnings about their callees. On the other hand, it's unacceptable to call user_access_save()/user_access_restore() inside these functions, as this slows down the whole runtime heavily. Perhaps this problem can be solved on objtool side, as the mentioned reports aren't errors per se. Alexander Potapenko (42): stackdepot: check depot_index before accessing the stack slab stackdepot: build with -fno-builtin kasan: stackdepot: move filter_irq_stacks() to stackdepot.c stackdepot: reserve 5 extra bits in depot_stack_handle_t kmsan: add ReST documentation kmsan: gfp: introduce __GFP_NO_KMSAN_SHADOW kmsan: introduce __no_sanitize_memory and __SANITIZE_MEMORY__ kmsan: reduce vmalloc space kmsan: add KMSAN runtime core kmsan: KMSAN compiler API implementation kmsan: add KMSAN hooks for kernel subsystems kmsan: stackdepot: don't allocate KMSAN metadata for stackdepot kmsan: define READ_ONCE_NOCHECK() kmsan: make READ_ONCE_TASK_STACK() return initialized values kmsan: x86: sync metadata pages on page fault kmsan: add tests for KMSAN crypto: kmsan: disable accelerated configs under KMSAN kmsan: x86: disable UNWINDER_ORC under KMSAN kmsan: x86/asm: softirq: add KMSAN IRQ entry hooks kmsan: x86: increase stack sizes in KMSAN builds kmsan: disable KMSAN instrumentation for certain kernel parts kmsan: mm: call KMSAN hooks from SLUB code kmsan: mm: maintain KMSAN metadata for page operations kmsan: handle memory sent to/from USB kmsan: handle task creation and exiting kmsan: net: check the value of skb before sending it to the network kmsan: printk: treat the result of vscnprintf() as initialized kmsan: disable instrumentation of certain functions kmsan: unpoison |tlb| in arch_tlb_gather_mmu() kmsan: use __msan_ string functions where possible. kmsan: hooks for copy_to_user() and friends kmsan: init: call KMSAN initialization routines kmsan: enable KMSAN builds kmsan: handle /dev/[u]random kmsan: virtio: check/unpoison scatterlist in vring_map_one_sg() kmsan: disable strscpy() optimization under KMSAN kmsan: add iomap support kmsan: dma: unpoison memory mapped by dma_direct_map_page() kmsan: disable physical page merging in biovec kmsan: ext4: skip block merging logic in ext4_mpage_readpages for KMSAN x86: kasan: kmsan: support CONFIG_GENERIC_CSUM on x86, enable it for KASAN/KMSAN kmsan: x86/uprobes: unpoison regs in arch_uprobe_exception_notify() To: Alexander Potapenko Cc: Alexander Viro Cc: Andreas Dilger Cc: Andrew Morton Cc: Andrey Konovalov Cc: Andrey Ryabinin Cc: Andy Lutomirski Cc: Ard Biesheuvel Cc: Arnd Bergmann Cc: Christoph Hellwig Cc: Christoph Hellwig Cc: Darrick J. Wong Cc: "David S. Miller" Cc: Dmitry Torokhov Cc: Dmitry Vyukov Cc: Eric Biggers Cc: Eric Dumazet Cc: Eric Van Hensbergen Cc: Greg Kroah-Hartman Cc: Harry Wentland Cc: Herbert Xu Cc: Ilya Leoshkevich Cc: Ingo Molnar Cc: Jason Wang Cc: Jens Axboe Cc: Marek Szyprowski Cc: Marco Elver Cc: Mark Rutland Cc: Martin K. Petersen Cc: Martin Schwidefsky Cc: Matthew Wilcox Cc: "Michael S. Tsirkin" Cc: Michal Simek Cc: Petr Mladek Cc: Qian Cai Cc: Randy Dunlap Cc: Robin Murphy Cc: Sergey Senozhatsky Cc: Steven Rostedt Cc: Takashi Iwai Cc: "Theodore Ts'o" Cc: Thomas Gleixner Cc: Vasily Gorbik Cc: Vegard Nossum Cc: Wolfram Sang Cc: linux-mm@kvack.org Documentation/dev-tools/index.rst | 1 + Documentation/dev-tools/kmsan.rst | 424 ++++++++++++++ Makefile | 3 +- arch/x86/Kconfig | 5 + arch/x86/Kconfig.debug | 3 + arch/x86/boot/Makefile | 2 + arch/x86/boot/compressed/Makefile | 2 + arch/x86/boot/compressed/misc.h | 1 + arch/x86/entry/common.c | 2 + arch/x86/entry/entry_64.S | 16 + arch/x86/entry/vdso/Makefile | 4 + arch/x86/include/asm/checksum.h | 10 +- arch/x86/include/asm/irq_regs.h | 2 + arch/x86/include/asm/kmsan.h | 93 +++ arch/x86/include/asm/page_64.h | 13 + arch/x86/include/asm/page_64_types.h | 12 +- arch/x86/include/asm/pgtable_64_types.h | 15 + arch/x86/include/asm/string_64.h | 23 +- arch/x86/include/asm/syscall_wrapper.h | 2 + arch/x86/include/asm/uaccess.h | 10 + arch/x86/include/asm/unwind.h | 10 +- arch/x86/kernel/Makefile | 4 + arch/x86/kernel/apic/apic.c | 3 + arch/x86/kernel/cpu/Makefile | 1 + arch/x86/kernel/dumpstack_64.c | 5 + arch/x86/kernel/process_64.c | 5 + arch/x86/kernel/traps.c | 13 +- arch/x86/kernel/uprobes.c | 7 +- arch/x86/lib/Makefile | 2 + arch/x86/mm/Makefile | 3 + arch/x86/mm/fault.c | 20 + arch/x86/mm/ioremap.c | 3 + arch/x86/realmode/rm/Makefile | 3 + block/blk.h | 7 + crypto/Kconfig | 26 + drivers/char/random.c | 6 + drivers/firmware/efi/libstub/Makefile | 2 + .../firmware/efi/libstub/efi-stub-helper.c | 5 + drivers/firmware/efi/libstub/tpm.c | 5 + drivers/usb/core/urb.c | 2 + drivers/virtio/virtio_ring.c | 10 +- fs/ext4/readpage.c | 10 + include/asm-generic/cacheflush.h | 7 +- include/asm-generic/uaccess.h | 12 +- include/linux/compiler-clang.h | 7 + include/linux/compiler-gcc.h | 5 + include/linux/compiler.h | 14 +- include/linux/gfp.h | 4 +- include/linux/highmem.h | 3 + include/linux/kmsan-checks.h | 127 ++++ include/linux/kmsan.h | 335 +++++++++++ include/linux/mm_types.h | 9 + include/linux/sched.h | 5 + include/linux/stackdepot.h | 10 + include/linux/string.h | 2 + include/linux/uaccess.h | 34 +- init/main.c | 3 + kernel/Makefile | 1 + kernel/dma/direct.c | 1 + kernel/exit.c | 2 + kernel/fork.c | 2 + kernel/kthread.c | 2 + kernel/locking/Makefile | 4 + kernel/printk/printk.c | 6 + kernel/sched/core.c | 22 + kernel/softirq.c | 5 + lib/Kconfig.debug | 2 + lib/Kconfig.kmsan | 22 + lib/Makefile | 7 + lib/iomap.c | 40 ++ lib/ioremap.c | 5 + lib/iov_iter.c | 14 +- lib/stackdepot.c | 69 ++- lib/string.c | 8 + lib/test_kmsan.c | 229 ++++++++ lib/usercopy.c | 8 +- mm/Makefile | 1 + mm/gup.c | 3 + mm/kasan/common.c | 23 - mm/kmsan/Makefile | 11 + mm/kmsan/kmsan.c | 547 ++++++++++++++++++ mm/kmsan/kmsan.h | 161 ++++++ mm/kmsan/kmsan_entry.c | 38 ++ mm/kmsan/kmsan_hooks.c | 416 +++++++++++++ mm/kmsan/kmsan_init.c | 79 +++ mm/kmsan/kmsan_instr.c | 229 ++++++++ mm/kmsan/kmsan_report.c | 143 +++++ mm/kmsan/kmsan_shadow.c | 456 +++++++++++++++ mm/kmsan/kmsan_shadow.h | 30 + mm/memory.c | 2 + mm/mmu_gather.c | 10 + mm/page_alloc.c | 17 + mm/slub.c | 29 +- mm/vmalloc.c | 24 +- net/sched/sch_generic.c | 2 + scripts/Makefile.kmsan | 12 + scripts/Makefile.lib | 6 + 97 files changed, 3988 insertions(+), 72 deletions(-) create mode 100644 Documentation/dev-tools/kmsan.rst create mode 100644 arch/x86/include/asm/kmsan.h create mode 100644 include/linux/kmsan-checks.h create mode 100644 include/linux/kmsan.h create mode 100644 lib/Kconfig.kmsan create mode 100644 lib/test_kmsan.c create mode 100644 mm/kmsan/Makefile create mode 100644 mm/kmsan/kmsan.c create mode 100644 mm/kmsan/kmsan.h create mode 100644 mm/kmsan/kmsan_entry.c create mode 100644 mm/kmsan/kmsan_hooks.c create mode 100644 mm/kmsan/kmsan_init.c create mode 100644 mm/kmsan/kmsan_instr.c create mode 100644 mm/kmsan/kmsan_report.c create mode 100644 mm/kmsan/kmsan_shadow.c create mode 100644 mm/kmsan/kmsan_shadow.h create mode 100644 scripts/Makefile.kmsan -- 2.24.1.735.g03f4e72817-goog