Eric Lee / smarc-fsl-linux-kernel

19 Mar, 2018

1 commit

  • 0ced0c46b   Fix misannotated out-of-line _copy_to_user() ... Browse Code »

    [ Upstream commit a0e94598e6b6c0d1df6a5fa14eb7c767ca817a20 ]

    Destination is a kernel pointer and source - a userland one
    in _copy_from_user(); _copy_to_user() is the other way round.

    Fixes: d597580d37377 ("generic ...copy_..._user primitives")
    Signed-off-by: Christophe Leroy
    Signed-off-by: Al Viro
    Signed-off-by: Sasha Levin
    Signed-off-by: Greg Kroah-Hartman

    Christophe Leroy
     

02 Nov, 2017

1 commit

  • b24413180   License cleanup: add SPDX GPL-2.0 license identifier to files with no license ... Browse Code »

    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
     

30 Jun, 2017

1 commit

29 Mar, 2017

1 commit

31 Aug, 2016

1 commit

  • 0d025d271   mm/usercopy: get rid of CONFIG_DEBUG_STRICT_USER_COPY_CHECKS ... Browse Code »

    There are three usercopy warnings which are currently being silenced for
    gcc 4.6 and newer:

    1) "copy_from_user() buffer size is too small" compile warning/error

    This is a static warning which happens when object size and copy size
    are both const, and copy size > object size. I didn't see any false
    positives for this one. So the function warning attribute seems to
    be working fine here.

    Note this scenario is always a bug and so I think it should be
    changed to *always* be an error, regardless of
    CONFIG_DEBUG_STRICT_USER_COPY_CHECKS.

    2) "copy_from_user() buffer size is not provably correct" compile warning

    This is another static warning which happens when I enable
    __compiletime_object_size() for new compilers (and
    CONFIG_DEBUG_STRICT_USER_COPY_CHECKS). It happens when object size
    is const, but copy size is *not*. In this case there's no way to
    compare the two at build time, so it gives the warning. (Note the
    warning is a byproduct of the fact that gcc has no way of knowing
    whether the overflow function will be called, so the call isn't dead
    code and the warning attribute is activated.)

    So this warning seems to only indicate "this is an unusual pattern,
    maybe you should check it out" rather than "this is a bug".

    I get 102(!) of these warnings with allyesconfig and the
    __compiletime_object_size() gcc check removed. I don't know if there
    are any real bugs hiding in there, but from looking at a small
    sample, I didn't see any. According to Kees, it does sometimes find
    real bugs. But the false positive rate seems high.

    3) "Buffer overflow detected" runtime warning

    This is a runtime warning where object size is const, and copy size >
    object size.

    All three warnings (both static and runtime) were completely disabled
    for gcc 4.6 with the following commit:

    2fb0815c9ee6 ("gcc4: disable __compiletime_object_size for GCC 4.6+")

    That commit mistakenly assumed that the false positives were caused by a
    gcc bug in __compiletime_object_size(). But in fact,
    __compiletime_object_size() seems to be working fine. The false
    positives were instead triggered by #2 above. (Though I don't have an
    explanation for why the warnings supposedly only started showing up in
    gcc 4.6.)

    So remove warning #2 to get rid of all the false positives, and re-enable
    warnings #1 and #3 by reverting the above commit.

    Furthermore, since #1 is a real bug which is detected at compile time,
    upgrade it to always be an error.

    Having done all that, CONFIG_DEBUG_STRICT_USER_COPY_CHECKS is no longer
    needed.

    Signed-off-by: Josh Poimboeuf
    Cc: Kees Cook
    Cc: Thomas Gleixner
    Cc: Ingo Molnar
    Cc: "H . Peter Anvin"
    Cc: Andy Lutomirski
    Cc: Steven Rostedt
    Cc: Brian Gerst
    Cc: Peter Zijlstra
    Cc: Frederic Weisbecker
    Cc: Byungchul Park
    Cc: Nilay Vaish
    Signed-off-by: Linus Torvalds

    Josh Poimboeuf
     

01 May, 2013

1 commit

  • 446f24d11   Kconfig: consolidate CONFIG_DEBUG_STRICT_USER_COPY_CHECKS ... Browse Code »

    The help text for this config is duplicated across the x86, parisc, and
    s390 Kconfig.debug files. Arnd Bergman noted that the help text was
    slightly misleading and should be fixed to state that enabling this
    option isn't a problem when using pre 4.4 gcc.

    To simplify the rewording, consolidate the text into lib/Kconfig.debug
    and modify it there to be more explicit about when you should say N to
    this config.

    Also, make the text a bit more generic by stating that this option
    enables compile time checks so we can cover architectures which emit
    warnings vs. ones which emit errors. The details of how an
    architecture decided to implement the checks isn't as important as the
    concept of compile time checking of copy_from_user() calls.

    While we're doing this, remove all the copy_from_user_overflow() code
    that's duplicated many times and place it into lib/ so that any
    architecture supporting this option can get the function for free.

    Signed-off-by: Stephen Boyd
    Acked-by: Arnd Bergmann
    Acked-by: Ingo Molnar
    Acked-by: H. Peter Anvin
    Cc: Arjan van de Ven
    Acked-by: Helge Deller
    Cc: Heiko Carstens
    Cc: Stephen Rothwell
    Cc: Chris Metcalf
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Stephen Boyd