lkml.org 
[lkml]   [2021]   [Nov]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 4.19 252/323] fortify: Explicitly disable Clang support
    Date
    From: Kees Cook <keescook@chromium.org>

    commit a52f8a59aef46b59753e583bf4b28fccb069ce64 upstream.

    Clang has never correctly compiled the FORTIFY_SOURCE defenses due to
    a couple bugs:

    Eliding inlines with matching __builtin_* names
    https://bugs.llvm.org/show_bug.cgi?id=50322

    Incorrect __builtin_constant_p() of some globals
    https://bugs.llvm.org/show_bug.cgi?id=41459

    In the process of making improvements to the FORTIFY_SOURCE defenses, the
    first (silent) bug (coincidentally) becomes worked around, but exposes
    the latter which breaks the build. As such, Clang must not be used with
    CONFIG_FORTIFY_SOURCE until at least latter bug is fixed (in Clang 13),
    and the fortify routines have been rearranged.

    Update the Kconfig to reflect the reality of the current situation.

    Signed-off-by: Kees Cook <keescook@chromium.org>
    Acked-by: Nick Desaulniers <ndesaulniers@google.com>
    Link: https://lore.kernel.org/lkml/CAKwvOd=A+ueGV2ihdy5GtgR2fQbcXjjAtVxv3=cPjffpebZB7A@mail.gmail.com
    Cc: Nathan Chancellor <nathan@kernel.org>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    ---
    security/Kconfig | 3 +++
    1 file changed, 3 insertions(+)

    --- a/security/Kconfig
    +++ b/security/Kconfig
    @@ -191,6 +191,9 @@ config HARDENED_USERCOPY_PAGESPAN
    config FORTIFY_SOURCE
    bool "Harden common str/mem functions against buffer overflows"
    depends on ARCH_HAS_FORTIFY_SOURCE
    + # https://bugs.llvm.org/show_bug.cgi?id=50322
    + # https://bugs.llvm.org/show_bug.cgi?id=41459
    + depends on !CC_IS_CLANG
    help
    Detect overflows of buffers in common string and memory functions
    where the compiler can determine and validate the buffer sizes.

    \
     
     \ /
      Last update: 2021-11-24 14:13    [W:4.268 / U:0.196 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site