27 May, 2020

1 commit

  • commit 33cd65e73abd693c00c4156cf23677c453b41b3b upstream.

    During early boot, while KASAN is not yet initialized, it is possible to
    enter reporting code-path and end up in kasan_report().

    While uninitialized, the branch there prevents generating any reports,
    however, under certain circumstances when branches are being traced
    (TRACE_BRANCH_PROFILING), we may recurse deep enough to cause kernel
    reboots without warning.

    To prevent similar issues in future, we should disable branch tracing
    for the core runtime.

    [elver@google.com: remove duplicate DISABLE_BRANCH_PROFILING, per Qian Cai]
    Link: https://lore.kernel.org/lkml/20200517011732.GE24705@shao2-debian/
    Link: http://lkml.kernel.org/r/20200522075207.157349-1-elver@google.com
    Reported-by: kernel test robot
    Signed-off-by: Marco Elver
    Signed-off-by: Andrew Morton
    Reviewed-by: Andrey Konovalov
    Cc: Dmitry Vyukov
    Cc: Alexander Potapenko
    Cc: Andrey Ryabinin
    Cc: Qian Cai
    Cc:
    Link: http://lkml.kernel.org/r//20200517011732.GE24705@shao2-debian/
    Link: http://lkml.kernel.org/r/20200519182459.87166-1-elver@google.com
    Signed-off-by: Linus Torvalds
    Signed-off-by: Greg Kroah-Hartman

    Marco Elver
     

13 Jul, 2019

1 commit

  • This changes {,__}kasan_check_{read,write} functions to return a boolean
    denoting if the access was valid or not.

    [sfr@canb.auug.org.au: include types.h for "bool"]
    Link: http://lkml.kernel.org/r/20190705184949.13cdd021@canb.auug.org.au
    Link: http://lkml.kernel.org/r/20190626142014.141844-3-elver@google.com
    Signed-off-by: Marco Elver
    Signed-off-by: Stephen Rothwell
    Reviewed-by: Andrey Ryabinin
    Cc: Dmitry Vyukov
    Cc: Alexander Potapenko
    Cc: Andrey Konovalov
    Cc: Christoph Lameter
    Cc: Pekka Enberg
    Cc: David Rientjes
    Cc: Joonsoo Kim
    Cc: Mark Rutland
    Cc: Kees Cook
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Marco Elver
     

06 Mar, 2019

1 commit

  • Use after scope bugs detector seems to be almost entirely useless for
    the linux kernel. It exists over two years, but I've seen only one
    valid bug so far [1]. And the bug was fixed before it has been
    reported. There were some other use-after-scope reports, but they were
    false-positives due to different reasons like incompatibility with
    structleak plugin.

    This feature significantly increases stack usage, especially with GCC <
    9 version, and causes a 32K stack overflow. It probably adds
    performance penalty too.

    Given all that, let's remove use-after-scope detector entirely.

    While preparing this patch I've noticed that we mistakenly enable
    use-after-scope detection for clang compiler regardless of
    CONFIG_KASAN_EXTRA setting. This is also fixed now.

    [1] http://lkml.kernel.org/r/

    Link: http://lkml.kernel.org/r/20190111185842.13978-1-aryabinin@virtuozzo.com
    Signed-off-by: Andrey Ryabinin
    Acked-by: Will Deacon [arm64]
    Cc: Qian Cai
    Cc: Alexander Potapenko
    Cc: Dmitry Vyukov
    Cc: Catalin Marinas
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Andrey Ryabinin
     

29 Dec, 2018

3 commits

  • This patch adds a "SPDX-License-Identifier: GPL-2.0" mark to all source
    files under mm/kasan.

    Link: http://lkml.kernel.org/r/bce2d1e618afa5142e81961ab8fa4b4165337380.1544099024.git.andreyknvl@google.com
    Signed-off-by: Andrey Konovalov
    Reviewed-by: Andrey Ryabinin
    Reviewed-by: Dmitry Vyukov
    Cc: Christoph Lameter
    Cc: Mark Rutland
    Cc: Will Deacon
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Andrey Konovalov
     
  • This commit splits the current CONFIG_KASAN config option into two:
    1. CONFIG_KASAN_GENERIC, that enables the generic KASAN mode (the one
    that exists now);
    2. CONFIG_KASAN_SW_TAGS, that enables the software tag-based KASAN mode.

    The name CONFIG_KASAN_SW_TAGS is chosen as in the future we will have
    another hardware tag-based KASAN mode, that will rely on hardware memory
    tagging support in arm64.

    With CONFIG_KASAN_SW_TAGS enabled, compiler options are changed to
    instrument kernel files with -fsantize=kernel-hwaddress (except the ones
    for which KASAN_SANITIZE := n is set).

    Both CONFIG_KASAN_GENERIC and CONFIG_KASAN_SW_TAGS support both
    CONFIG_KASAN_INLINE and CONFIG_KASAN_OUTLINE instrumentation modes.

    This commit also adds empty placeholder (for now) implementation of
    tag-based KASAN specific hooks inserted by the compiler and adjusts
    common hooks implementation.

    While this commit adds the CONFIG_KASAN_SW_TAGS config option, this option
    is not selectable, as it depends on HAVE_ARCH_KASAN_SW_TAGS, which we will
    enable once all the infrastracture code has been added.

    Link: http://lkml.kernel.org/r/b2550106eb8a68b10fefbabce820910b115aa853.1544099024.git.andreyknvl@google.com
    Signed-off-by: Andrey Konovalov
    Reviewed-by: Andrey Ryabinin
    Reviewed-by: Dmitry Vyukov
    Cc: Christoph Lameter
    Cc: Mark Rutland
    Cc: Will Deacon
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Andrey Konovalov
     
  • We now have two KASAN modes: generic KASAN and tag-based KASAN. Rename
    kasan.c to generic.c to reflect that. Also rename kasan_init.c to init.c
    as it contains initialization code for both KASAN modes.

    Link: http://lkml.kernel.org/r/88c6fd2a883e459e6242030497230e5fb0d44d44.1544099024.git.andreyknvl@google.com
    Signed-off-by: Andrey Konovalov
    Reviewed-by: Andrey Ryabinin
    Reviewed-by: Dmitry Vyukov
    Cc: Christoph Lameter
    Cc: Mark Rutland
    Cc: Will Deacon
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Andrey Konovalov