08 Jun, 2018

1 commit

  • Move the test for -fstack-protector(-strong) option to Kconfig.

    If the compiler does not support the option, the corresponding menu
    is automatically hidden. If STRONG is not supported, it will fall
    back to REGULAR. If REGULAR is not supported, it will be disabled.
    This means, AUTO is implicitly handled by the dependency solver of
    Kconfig, hence removed.

    I also turned the 'choice' into only two boolean symbols. The use of
    'choice' is not a good idea here, because all of all{yes,mod,no}config
    would choose the first visible value, while we want allnoconfig to
    disable as many features as possible.

    X86 has additional shell scripts in case the compiler supports those
    options, but generates broken code. I added CC_HAS_SANE_STACKPROTECTOR
    to test this. I had to add -m32 to gcc-x86_32-has-stack-protector.sh
    to make it work correctly.

    Signed-off-by: Masahiro Yamada
    Acked-by: Kees Cook

    Masahiro Yamada
     

02 Nov, 2017

1 commit

  • Many source files in the tree are missing licensing information, which
    makes it harder for compliance tools to determine the correct license.

    By default all files without license information are under the default
    license of the kernel, which is GPL version 2.

    Update the files which contain no license information with the 'GPL-2.0'
    SPDX license identifier. The SPDX identifier is a legally binding
    shorthand, which can be used instead of the full boiler plate text.

    This patch is based on work done by Thomas Gleixner and Kate Stewart and
    Philippe Ombredanne.

    How this work was done:

    Patches were generated and checked against linux-4.14-rc6 for a subset of
    the use cases:
    - file had no licensing information it it.
    - file was a */uapi/* one with no licensing information in it,
    - file was a */uapi/* one with existing licensing information,

    Further patches will be generated in subsequent months to fix up cases
    where non-standard license headers were used, and references to license
    had to be inferred by heuristics based on keywords.

    The analysis to determine which SPDX License Identifier to be applied to
    a file was done in a spreadsheet of side by side results from of the
    output of two independent scanners (ScanCode & Windriver) producing SPDX
    tag:value files created by Philippe Ombredanne. Philippe prepared the
    base worksheet, and did an initial spot review of a few 1000 files.

    The 4.13 kernel was the starting point of the analysis with 60,537 files
    assessed. Kate Stewart did a file by file comparison of the scanner
    results in the spreadsheet to determine which SPDX license identifier(s)
    to be applied to the file. She confirmed any determination that was not
    immediately clear with lawyers working with the Linux Foundation.

    Criteria used to select files for SPDX license identifier tagging was:
    - Files considered eligible had to be source code files.
    - Make and config files were included as candidates if they contained >5
    lines of source
    - File already had some variant of a license header in it (even if
    Reviewed-by: Philippe Ombredanne
    Reviewed-by: Thomas Gleixner
    Signed-off-by: Greg Kroah-Hartman

    Greg Kroah-Hartman
     

20 Aug, 2014

1 commit


03 Oct, 2012

1 commit

  • The correct syntax for gcc -x is "gcc -x assembler", not
    "gcc -xassembler". Even though the latter happens to work, the former
    is what is documented in the manual page and thus what gcc wrappers
    such as icecream do expect.

    This isn't a cosmetic change. The missing space prevents icecream from
    recognizing compilation tasks it can't handle, leading to silent kernel
    miscompilations.

    Besides me, credits go to Michael Matz and Dirk Mueller for
    investigating the miscompilation issue and tracking it down to this
    incorrect -x parameter syntax.

    Signed-off-by: Jean Delvare
    Acked-by: Ingo Molnar
    Cc: stable@vger.kernel.org
    Cc: Bernhard Walle
    Cc: Michal Marek
    Cc: Ralf Baechle
    Signed-off-by: Michal Marek

    Jean Delvare
     

11 Feb, 2009

1 commit


10 Feb, 2009

1 commit

  • Impact: stack protector for x86_32

    Implement stack protector for x86_32. GDT entry 28 is used for it.
    It's set to point to stack_canary-20 and have the length of 24 bytes.
    CONFIG_CC_STACKPROTECTOR turns off CONFIG_X86_32_LAZY_GS and sets %gs
    to the stack canary segment on entry. As %gs is otherwise unused by
    the kernel, the canary can be anywhere. It's defined as a percpu
    variable.

    x86_32 exception handlers take register frame on stack directly as
    struct pt_regs. With -fstack-protector turned on, gcc copies the
    whole structure after the stack canary and (of course) doesn't copy
    back on return thus losing all changed. For now, -fno-stack-protector
    is added to all files which contain those functions. We definitely
    need something better.

    Signed-off-by: Tejun Heo
    Signed-off-by: Ingo Molnar

    Tejun Heo