1. 19 Mar, 2018 1 commit
  2. 02 Nov, 2017 1 commit
    • Greg Kroah-Hartman's avatar
      License cleanup: add SPDX GPL-2.0 license identifier to files with no license · b2441318
      Greg Kroah-Hartman authored
      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 <5
         lines).
      
      All documentation files were explicitly excluded.
      
      The following heuristics were used to determine which SPDX license
      identifiers to apply.
      
       - when both scanners couldn't find any license traces, file was
         considered to have no license information in it, and the top level
         COPYING file license applied.
      
         For non */uapi/* files that summary was:
      
         SPDX license identifier                            # files
         ---------------------------------------------------|-------
         GPL-2.0                                              11139
      
         and resulted in the first patch in this series.
      
         If that file was a */uapi/* path one, it was "GPL-2.0 WITH
         Linux-syscall-note" otherwise it was "GPL-2.0".  Results of that was:
      
         SPDX license identifier                            # files
         ---------------------------------------------------|-------
         GPL-2.0 WITH Linux-syscall-note                        930
      
         and resulted in the second patch in this series.
      
       - if a file had some form of licensing information in it, and was one
         of the */uapi/* ones, it was denoted with the Linux-syscall-note if
         any GPL family license was found in the file or had no licensing in
         it (per prior point).  Results summary:
      
         SPDX license identifier                            # files
         ---------------------------------------------------|------
         GPL-2.0 WITH Linux-syscall-note                       270
         GPL-2.0+ WITH Linux-syscall-note                      169
         ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause)    21
         ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)    17
         LGPL-2.1+ WITH Linux-syscall-note                      15
         GPL-1.0+ WITH Linux-syscall-note                       14
         ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause)    5
         LGPL-2.0+ WITH Linux-syscall-note                       4
         LGPL-2.1 WITH Linux-syscall-note                        3
         ((GPL-2.0 WITH Linux-syscall-note) OR MIT)              3
         ((GPL-2.0 WITH Linux-syscall-note) AND MIT)             1
      
         and that resulted in the third patch in this series.
      
       - when the two scanners agreed on the detected license(s), that became
         the concluded license(s).
      
       - when there was disagreement between the two scanners (one detected a
         license but the other didn't, or they both detected different
         licenses) a manual inspection of the file occurred.
      
       - In most cases a manual inspection of the information in the file
         resulted in a clear resolution of the license that should apply (and
         which scanner probably needed to revisit its heuristics).
      
       - When it was not immediately clear, the license identifier was
         confirmed with lawyers working with the Linux Foundation.
      
       - If there was any question as to the appropriate license identifier,
         the file was flagged for further research and to be revisited later
         in time.
      
      In total, over 70 hours of logged manual review was done on the
      spreadsheet to determine the SPDX license identifiers to apply to the
      source files by Kate, Philippe, Thomas and, in some cases, confirmation
      by lawyers working with the Linux Foundation.
      
      Kate also obtained a third independent scan of the 4.13 code base from
      FOSSology, and compared selected files where the other two scanners
      disagreed against that SPDX file, to see if there was new insights.  The
      Windriver scanner is based on an older version of FOSSology in part, so
      they are related.
      
      Thomas did random spot checks in about 500 files from the spreadsheets
      for the uapi headers and agreed with SPDX license identifier in the
      files he inspected. For the non-uapi files Thomas did random spot checks
      in about 15000 files.
      
      In initial set of patches against 4.14-rc6, 3 files were found to have
      copy/paste license identifier errors, and have been fixed to reflect the
      correct identifier.
      
      Additionally Philippe spent 10 hours this week doing a detailed manual
      inspection and review of the 12,461 patched files from the initial patch
      version early this week with:
       - a full scancode scan run, collecting the matched texts, detected
         license ids and scores
       - reviewing anything where there was a license detected (about 500+
         files) to ensure that the applied SPDX license was correct
       - reviewing anything where there was no detection but the patch license
         was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
         SPDX license was correct
      
      This produced a worksheet with 20 files needing minor correction.  This
      worksheet was then exported into 3 different .csv files for the
      different types of files to be modified.
      
      These .csv files were then reviewed by Greg.  Thomas wrote a script to
      parse the csv files and add the proper SPDX tag to the file, in the
      format that the file expected.  This script was further refined by Greg
      based on the output to detect more types of files automatically and to
      distinguish between header and source .c files (which need different
      comment types.)  Finally Greg ran the script using the .csv files to
      generate the patches.
      Reviewed-by: 's avatarKate Stewart <kstewart@linuxfoundation.org>
      Reviewed-by: 's avatarPhilippe Ombredanne <pombredanne@nexb.com>
      Reviewed-by: 's avatarThomas Gleixner <tglx@linutronix.de>
      Signed-off-by: 's avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      b2441318
  3. 30 Jun, 2017 1 commit
  4. 28 Mar, 2017 1 commit
  5. 30 Aug, 2016 1 commit
    • Josh Poimboeuf's avatar
      mm/usercopy: get rid of CONFIG_DEBUG_STRICT_USER_COPY_CHECKS · 0d025d27
      Josh Poimboeuf authored
      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:
      
        2fb0815c ("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: 's avatarJosh Poimboeuf <jpoimboe@redhat.com>
      Cc: Kees Cook <keescook@chromium.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Ingo Molnar <mingo@kernel.org>
      Cc: "H . Peter Anvin" <hpa@zytor.com>
      Cc: Andy Lutomirski <luto@amacapital.net>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      Cc: Brian Gerst <brgerst@gmail.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Frederic Weisbecker <fweisbec@gmail.com>
      Cc: Byungchul Park <byungchul.park@lge.com>
      Cc: Nilay Vaish <nilayvaish@gmail.com>
      Signed-off-by: 's avatarLinus Torvalds <torvalds@linux-foundation.org>
      0d025d27
  6. 01 May, 2013 1 commit
    • Stephen Boyd's avatar
      Kconfig: consolidate CONFIG_DEBUG_STRICT_USER_COPY_CHECKS · 446f24d1
      Stephen Boyd authored
      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: 's avatarStephen Boyd <sboyd@codeaurora.org>
      Acked-by: 's avatarArnd Bergmann <arnd@arndb.de>
      Acked-by: 's avatarIngo Molnar <mingo@kernel.org>
      Acked-by: 's avatarH. Peter Anvin <hpa@zytor.com>
      Cc: Arjan van de Ven <arjan@linux.intel.com>
      Acked-by: 's avatarHelge Deller <deller@gmx.de>
      Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
      Cc: Stephen Rothwell <sfr@canb.auug.org.au>
      Cc: Chris Metcalf <cmetcalf@tilera.com>
      Signed-off-by: 's avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: 's avatarLinus Torvalds <torvalds@linux-foundation.org>
      446f24d1
  7. 26 Feb, 2010 1 commit
  8. 11 Dec, 2009 1 commit