1. 15 5月, 2018 1 次提交
    • D
      x86/asm/memcpy_mcsafe: Return bytes remaining · 60622d68
      Dan Williams 提交于
      Machine check safe memory copies are currently deployed in the pmem
      driver whenever reading from persistent memory media, so that -EIO is
      returned rather than triggering a kernel panic. While this protects most
      pmem accesses, it is not complete in the filesystem-dax case. When
      filesystem-dax is enabled reads may bypass the block layer and the
      driver via dax_iomap_actor() and its usage of copy_to_iter().
      
      In preparation for creating a copy_to_iter() variant that can handle
      machine checks, teach memcpy_mcsafe() to return the number of bytes
      remaining rather than -EFAULT when an exception occurs.
      Co-developed-by: NTony Luck <tony.luck@intel.com>
      Signed-off-by: NDan Williams <dan.j.williams@intel.com>
      Cc: Al Viro <viro@zeniv.linux.org.uk>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Cc: Andy Lutomirski <luto@amacapital.net>
      Cc: Borislav Petkov <bp@alien8.de>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Tony Luck <tony.luck@intel.com>
      Cc: hch@lst.de
      Cc: linux-fsdevel@vger.kernel.org
      Cc: linux-nvdimm@lists.01.org
      Link: http://lkml.kernel.org/r/152539238119.31796.14318473522414462886.stgit@dwillia2-desk3.amr.corp.intel.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
      60622d68
  2. 20 1月, 2018 1 次提交
    • T
      string: drop __must_check from strscpy() and restore strscpy() usages in cgroup · 08a77676
      Tejun Heo 提交于
      e7fd37ba ("cgroup: avoid copying strings longer than the buffers")
      converted possibly unsafe strncpy() usages in cgroup to strscpy().
      However, although the callsites are completely fine with truncated
      copied, because strscpy() is marked __must_check, it led to the
      following warnings.
      
        kernel/cgroup/cgroup.c: In function ‘cgroup_file_name’:
        kernel/cgroup/cgroup.c:1400:10: warning: ignoring return value of ‘strscpy’, declared with attribute warn_unused_result [-Wunused-result]
           strscpy(buf, cft->name, CGROUP_FILE_NAME_MAX);
      	       ^
      
      To avoid the warnings, 50034ed4 ("cgroup: use strlcpy() instead of
      strscpy() to avoid spurious warning") switched them to strlcpy().
      
      strlcpy() is worse than strlcpy() because it unconditionally runs
      strlen() on the source string, and the only reason we switched to
      strlcpy() here was because it was lacking __must_check, which doesn't
      reflect any material differences between the two function.  It's just
      that someone added __must_check to strscpy() and not to strlcpy().
      
      These basic string copy operations are used in variety of ways, and
      one of not-so-uncommon use cases is safely handling truncated copies,
      where the caller naturally doesn't care about the return value.  The
      __must_check doesn't match the actual use cases and forces users to
      opt for inferior variants which lack __must_check by happenstance or
      spread ugly (void) casts.
      
      Remove __must_check from strscpy() and restore strscpy() usages in
      cgroup.
      Signed-off-by: NTejun Heo <tj@kernel.org>
      Suggested-by: NLinus Torvalds <torvalds@linux-foundation.org>
      Cc: Ma Shimiao <mashimiao.fnst@cn.fujitsu.com>
      Cc: Arnd Bergmann <arnd@arndb.de>
      Cc: Chris Metcalf <cmetcalf@ezchip.com>
      08a77676
  3. 08 1月, 2018 1 次提交
  4. 15 12月, 2017 1 次提交
    • A
      string.h: workaround for increased stack usage · 146734b0
      Arnd Bergmann 提交于
      The hardened strlen() function causes rather large stack usage in at
      least one file in the kernel, in particular when CONFIG_KASAN is
      enabled:
      
        drivers/media/usb/em28xx/em28xx-dvb.c: In function 'em28xx_dvb_init':
        drivers/media/usb/em28xx/em28xx-dvb.c:2062:1: error: the frame size of 3256 bytes is larger than 204 bytes [-Werror=frame-larger-than=]
      
      Analyzing this problem led to the discovery that gcc fails to merge the
      stack slots for the i2c_board_info[] structures after we strlcpy() into
      them, due to the 'noreturn' attribute on the source string length check.
      
      I reported this as a gcc bug, but it is unlikely to get fixed for gcc-8,
      since it is relatively easy to work around, and it gets triggered
      rarely.  An earlier workaround I did added an empty inline assembly
      statement before the call to fortify_panic(), which works surprisingly
      well, but is really ugly and unintuitive.
      
      This is a new approach to the same problem, this time addressing it by
      not calling the 'extern __real_strnlen()' function for string constants
      where __builtin_strlen() is a compile-time constant and therefore known
      to be safe.
      
      We do this by checking if the last character in the string is a
      compile-time constant '\0'.  If it is, we can assume that strlen() of
      the string is also constant.
      
      As a side-effect, this should also improve the object code output for
      any other call of strlen() on a string constant.
      
      [akpm@linux-foundation.org: add comment]
      Link: http://lkml.kernel.org/r/20171205215143.3085755-1-arnd@arndb.de
      Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82365
      Link: https://patchwork.kernel.org/patch/9980413/
      Link: https://patchwork.kernel.org/patch/9974047/
      Fixes: 6974f0c4 ("include/linux/string.h: add the option of fortified string.h functions")
      Signed-off-by: NArnd Bergmann <arnd@arndb.de>
      Cc: Kees Cook <keescook@chromium.org>
      Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
      Cc: Dmitry Vyukov <dvyukov@google.com>
      Cc: Alexander Potapenko <glider@google.com>
      Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
      Cc: Daniel Micay <danielmicay@gmail.com>
      Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
      Cc: Martin Wilck <mwilck@suse.com>
      Cc: Dan Williams <dan.j.williams@intel.com>
      Cc: <stable@vger.kernel.org>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      146734b0
  5. 02 11月, 2017 1 次提交
    • G
      License cleanup: add SPDX GPL-2.0 license identifier to files with no license · b2441318
      Greg Kroah-Hartman 提交于
      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: NKate Stewart <kstewart@linuxfoundation.org>
      Reviewed-by: NPhilippe Ombredanne <pombredanne@nexb.com>
      Reviewed-by: NThomas Gleixner <tglx@linutronix.de>
      Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      b2441318
  6. 12 9月, 2017 1 次提交
  7. 09 9月, 2017 1 次提交
    • M
      lib/string.c: add multibyte memset functions · 3b3c4bab
      Matthew Wilcox 提交于
      Patch series "Multibyte memset variations", v4.
      
      A relatively common idiom we're missing is a function to fill an area of
      memory with a pattern which is larger than a single byte.  I first
      noticed this with a zram patch which wanted to fill a page with an
      'unsigned long' value.  There turn out to be quite a few places in the
      kernel which can benefit from using an optimised function rather than a
      loop; sometimes text size, sometimes speed, and sometimes both.  The
      optimised PowerPC version (not included here) improves performance by
      about 30% on POWER8 on just the raw memset_l().
      
      Most of the extra lines of code come from the three testcases I added.
      
      This patch (of 8):
      
      memset16(), memset32() and memset64() are like memset(), but allow the
      caller to fill the destination with a value larger than a single byte.
      memset_l() and memset_p() allow the caller to use unsigned long and
      pointer values respectively.
      
      Link: http://lkml.kernel.org/r/20170720184539.31609-2-willy@infradead.orgSigned-off-by: NMatthew Wilcox <mawilcox@microsoft.com>
      Cc: "H. Peter Anvin" <hpa@zytor.com>
      Cc: "James E.J. Bottomley" <jejb@linux.vnet.ibm.com>
      Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
      Cc: David Miller <davem@davemloft.net>
      Cc: Ingo Molnar <mingo@elte.hu>
      Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
      Cc: Matt Turner <mattst88@gmail.com>
      Cc: Michael Ellerman <mpe@ellerman.id.au>
      Cc: Minchan Kim <minchan@kernel.org>
      Cc: Ralf Baechle <ralf@linux-mips.org>
      Cc: Richard Henderson <rth@twiddle.net>
      Cc: Russell King <rmk+kernel@armlinux.org.uk>
      Cc: Sam Ravnborg <sam@ravnborg.org>
      Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      3b3c4bab
  8. 29 8月, 2017 1 次提交
  9. 15 7月, 2017 1 次提交
  10. 13 7月, 2017 1 次提交
    • D
      include/linux/string.h: add the option of fortified string.h functions · 6974f0c4
      Daniel Micay 提交于
      This adds support for compiling with a rough equivalent to the glibc
      _FORTIFY_SOURCE=1 feature, providing compile-time and runtime buffer
      overflow checks for string.h functions when the compiler determines the
      size of the source or destination buffer at compile-time.  Unlike glibc,
      it covers buffer reads in addition to writes.
      
      GNU C __builtin_*_chk intrinsics are avoided because they would force a
      much more complex implementation.  They aren't designed to detect read
      overflows and offer no real benefit when using an implementation based
      on inline checks.  Inline checks don't add up to much code size and
      allow full use of the regular string intrinsics while avoiding the need
      for a bunch of _chk functions and per-arch assembly to avoid wrapper
      overhead.
      
      This detects various overflows at compile-time in various drivers and
      some non-x86 core kernel code.  There will likely be issues caught in
      regular use at runtime too.
      
      Future improvements left out of initial implementation for simplicity,
      as it's all quite optional and can be done incrementally:
      
      * Some of the fortified string functions (strncpy, strcat), don't yet
        place a limit on reads from the source based on __builtin_object_size of
        the source buffer.
      
      * Extending coverage to more string functions like strlcat.
      
      * It should be possible to optionally use __builtin_object_size(x, 1) for
        some functions (C strings) to detect intra-object overflows (like
        glibc's _FORTIFY_SOURCE=2), but for now this takes the conservative
        approach to avoid likely compatibility issues.
      
      * The compile-time checks should be made available via a separate config
        option which can be enabled by default (or always enabled) once enough
        time has passed to get the issues it catches fixed.
      
      Kees said:
       "This is great to have. While it was out-of-tree code, it would have
        blocked at least CVE-2016-3858 from being exploitable (improper size
        argument to strlcpy()). I've sent a number of fixes for
        out-of-bounds-reads that this detected upstream already"
      
      [arnd@arndb.de: x86: fix fortified memcpy]
        Link: http://lkml.kernel.org/r/20170627150047.660360-1-arnd@arndb.de
      [keescook@chromium.org: avoid panic() in favor of BUG()]
        Link: http://lkml.kernel.org/r/20170626235122.GA25261@beast
      [keescook@chromium.org: move from -mm, add ARCH_HAS_FORTIFY_SOURCE, tweak Kconfig help]
      Link: http://lkml.kernel.org/r/20170526095404.20439-1-danielmicay@gmail.com
      Link: http://lkml.kernel.org/r/1497903987-21002-8-git-send-email-keescook@chromium.orgSigned-off-by: NDaniel Micay <danielmicay@gmail.com>
      Signed-off-by: NKees Cook <keescook@chromium.org>
      Signed-off-by: NArnd Bergmann <arnd@arndb.de>
      Acked-by: NKees Cook <keescook@chromium.org>
      Cc: Mark Rutland <mark.rutland@arm.com>
      Cc: Daniel Axtens <dja@axtens.net>
      Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
      Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
      Cc: Chris Metcalf <cmetcalf@ezchip.com>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: "H. Peter Anvin" <hpa@zytor.com>
      Cc: Ingo Molnar <mingo@elte.hu>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      6974f0c4
  11. 06 7月, 2017 1 次提交
  12. 10 6月, 2017 1 次提交
    • D
      x86, uaccess: introduce copy_from_iter_flushcache for pmem / cache-bypass operations · 0aed55af
      Dan Williams 提交于
      The pmem driver has a need to transfer data with a persistent memory
      destination and be able to rely on the fact that the destination writes are not
      cached. It is sufficient for the writes to be flushed to a cpu-store-buffer
      (non-temporal / "movnt" in x86 terms), as we expect userspace to call fsync()
      to ensure data-writes have reached a power-fail-safe zone in the platform. The
      fsync() triggers a REQ_FUA or REQ_FLUSH to the pmem driver which will turn
      around and fence previous writes with an "sfence".
      
      Implement a __copy_from_user_inatomic_flushcache, memcpy_page_flushcache, and
      memcpy_flushcache, that guarantee that the destination buffer is not dirty in
      the cpu cache on completion. The new copy_from_iter_flushcache and sub-routines
      will be used to replace the "pmem api" (include/linux/pmem.h +
      arch/x86/include/asm/pmem.h). The availability of copy_from_iter_flushcache()
      and memcpy_flushcache() are gated by the CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE
      config symbol, and fallback to copy_from_iter_nocache() and plain memcpy()
      otherwise.
      
      This is meant to satisfy the concern from Linus that if a driver wants to do
      something beyond the normal nocache semantics it should be something private to
      that driver [1], and Al's concern that anything uaccess related belongs with
      the rest of the uaccess code [2].
      
      The first consumer of this interface is a new 'copy_from_iter' dax operation so
      that pmem can inject cache maintenance operations without imposing this
      overhead on other dax-capable drivers.
      
      [1]: https://lists.01.org/pipermail/linux-nvdimm/2017-January/008364.html
      [2]: https://lists.01.org/pipermail/linux-nvdimm/2017-April/009942.html
      
      Cc: <x86@kernel.org>
      Cc: Jan Kara <jack@suse.cz>
      Cc: Jeff Moyer <jmoyer@redhat.com>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: Christoph Hellwig <hch@lst.de>
      Cc: Toshi Kani <toshi.kani@hpe.com>
      Cc: "H. Peter Anvin" <hpa@zytor.com>
      Cc: Al Viro <viro@zeniv.linux.org.uk>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Matthew Wilcox <mawilcox@microsoft.com>
      Reviewed-by: NRoss Zwisler <ross.zwisler@linux.intel.com>
      Signed-off-by: NDan Williams <dan.j.williams@intel.com>
      0aed55af
  13. 26 4月, 2017 1 次提交
    • D
      x86, dax, pmem: remove indirection around memcpy_from_pmem() · 6abccd1b
      Dan Williams 提交于
      memcpy_from_pmem() maps directly to memcpy_mcsafe(). The wrapper
      serves no real benefit aside from affording a more generic function name
      than the x86-specific 'mcsafe'. However this would not be the first time
      that x86 terminology leaked into the global namespace. For lack of
      better name, just use memcpy_mcsafe() directly.
      
      This conversion also catches a place where we should have been using
      plain memcpy, acpi_nfit_blk_single_io().
      
      Cc: <x86@kernel.org>
      Cc: Jan Kara <jack@suse.cz>
      Cc: Jeff Moyer <jmoyer@redhat.com>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: Christoph Hellwig <hch@lst.de>
      Cc: "H. Peter Anvin" <hpa@zytor.com>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Matthew Wilcox <mawilcox@microsoft.com>
      Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
      Acked-by: NTony Luck <tony.luck@intel.com>
      Signed-off-by: NDan Williams <dan.j.williams@intel.com>
      6abccd1b
  14. 23 3月, 2017 1 次提交
  15. 20 5月, 2016 1 次提交
    • R
      include/linux: apply __malloc attribute · 48a27055
      Rasmus Villemoes 提交于
      Attach the malloc attribute to a few allocation functions.  This helps
      gcc generate better code by telling it that the return value doesn't
      alias any existing pointers (which is even more valuable given the
      pessimizations implied by -fno-strict-aliasing).
      
      A simple example of what this allows gcc to do can be seen by looking at
      the last part of drm_atomic_helper_plane_reset:
      
      	plane->state = kzalloc(sizeof(*plane->state), GFP_KERNEL);
      
      	if (plane->state) {
      		plane->state->plane = plane;
      		plane->state->rotation = BIT(DRM_ROTATE_0);
      	}
      
      which compiles to
      
          e8 99 bf d6 ff          callq  ffffffff8116d540 <kmem_cache_alloc_trace>
          48 85 c0                test   %rax,%rax
          48 89 83 40 02 00 00    mov    %rax,0x240(%rbx)
          74 11                   je     ffffffff814015c4 <drm_atomic_helper_plane_reset+0x64>
          48 89 18                mov    %rbx,(%rax)
          48 8b 83 40 02 00 00    mov    0x240(%rbx),%rax [*]
          c7 40 40 01 00 00 00    movl   $0x1,0x40(%rax)
      
      With this patch applied, the instruction at [*] is elided, since the
      store to plane->state->plane is known to not alter the value of
      plane->state.
      
      [akpm@linux-foundation.org: coding-style fixes]
      Signed-off-by: NRasmus Villemoes <linux@rasmusvillemoes.dk>
      Cc: Christoph Lameter <cl@linux.com>
      Cc: Pekka Enberg <penberg@kernel.org>
      Cc: David Rientjes <rientjes@google.com>
      Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
      Cc: Andi Kleen <ak@linux.intel.com>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      48a27055
  16. 18 3月, 2016 2 次提交
    • K
      lib: move strtobool() to kstrtobool() · ef951599
      Kees Cook 提交于
      Create the kstrtobool_from_user() helper and move strtobool() logic into
      the new kstrtobool() (matching all the other kstrto* functions).
      Provides an inline wrapper for existing strtobool() callers.
      Signed-off-by: NKees Cook <keescook@chromium.org>
      Cc: Joe Perches <joe@perches.com>
      Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
      Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
      Cc: Daniel Borkmann <daniel@iogearbox.net>
      Cc: Amitkumar Karwar <akarwar@marvell.com>
      Cc: Nishant Sarmukadam <nishants@marvell.com>
      Cc: Kalle Valo <kvalo@codeaurora.org>
      Cc: Steve French <sfrench@samba.org>
      Cc: Michael Ellerman <mpe@ellerman.id.au>
      Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
      Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      ef951599
    • A
      lib/string: introduce match_string() helper · 56b06081
      Andy Shevchenko 提交于
      Occasionally we have to search for an occurrence of a string in an array
      of strings.  Make a simple helper for that purpose.
      Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
      Cc: "David S. Miller" <davem@davemloft.net>
      Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
      Cc: David Airlie <airlied@linux.ie>
      Cc: David Woodhouse <dwmw2@infradead.org>
      Cc: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
      Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
      Cc: Heikki Krogerus <heikki.krogerus@linux.intel.com>
      Cc: Linus Walleij <linus.walleij@linaro.org>
      Cc: Mika Westerberg <mika.westerberg@linux.intel.com>
      Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
      Cc: Sebastian Reichel <sre@kernel.org>
      Cc: Tejun Heo <tj@kernel.org>
      Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      56b06081
  17. 04 1月, 2016 1 次提交
  18. 11 9月, 2015 1 次提交
    • C
      string: provide strscpy() · 30035e45
      Chris Metcalf 提交于
      The strscpy() API is intended to be used instead of strlcpy(),
      and instead of most uses of strncpy().
      
      - Unlike strlcpy(), it doesn't read from memory beyond (src + size).
      
      - Unlike strlcpy() or strncpy(), the API provides an easy way to check
        for destination buffer overflow: an -E2BIG error return value.
      
      - The provided implementation is robust in the face of the source
        buffer being asynchronously changed during the copy, unlike the
        current implementation of strlcpy().
      
      - Unlike strncpy(), the destination buffer will be NUL-terminated
        if the string in the source buffer is too long.
      
      - Also unlike strncpy(), the destination buffer will not be updated
        beyond the NUL termination, avoiding strncpy's behavior of zeroing
        the entire tail end of the destination buffer.  (A memset() after
        the strscpy() can be used if this behavior is desired.)
      
      - The implementation should be reasonably performant on all
        platforms since it uses the asm/word-at-a-time.h API rather than
        simple byte copy.  Kernel-to-kernel string copy is not considered
        to be performance critical in any case.
      Signed-off-by: NChris Metcalf <cmetcalf@ezchip.com>
      30035e45
  19. 26 6月, 2015 1 次提交
    • R
      lib/string.c: introduce strreplace() · 94df2904
      Rasmus Villemoes 提交于
      Strings are sometimes sanitized by replacing a certain character (often
      '/') by another (often '!').  In a few places, this is done the same way
      Schlemiel the Painter would do it.  Others are slightly smarter but still
      do multiple strchr() calls.  Introduce strreplace() to do this using a
      single function call and a single pass over the string.
      
      One would expect the return value to be one of three things: void, s, or
      the number of replacements made.  I chose the fourth, returning a pointer
      to the end of the string.  This is more likely to be useful (for example
      allowing the caller to avoid a strlen call).
      Signed-off-by: NRasmus Villemoes <linux@rasmusvillemoes.dk>
      Cc: "Theodore Ts'o" <tytso@mit.edu>
      Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
      Cc: Neil Brown <neilb@suse.de>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      Cc: Joe Perches <joe@perches.com>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      94df2904
  20. 14 2月, 2015 1 次提交
    • A
      mm/util: add kstrdup_const · a4bb1e43
      Andrzej Hajda 提交于
      kstrdup() is often used to duplicate strings where neither source neither
      destination will be ever modified.  In such case we can just reuse the
      source instead of duplicating it.  The problem is that we must be sure
      that the source is non-modifiable and its life-time is long enough.
      
      I suspect the good candidates for such strings are strings located in
      kernel .rodata section, they cannot be modifed because the section is
      read-only and their life-time is equal to kernel life-time.
      
      This small patchset proposes alternative version of kstrdup -
      kstrdup_const, which returns source string if it is located in .rodata
      otherwise it fallbacks to kstrdup.  To verify if the source is in
      .rodata function checks if the address is between sentinels
      __start_rodata, __end_rodata.  I guess it should work with all
      architectures.
      
      The main patch is accompanied by four patches constifying kstrdup for
      cases where situtation described above happens frequently.
      
      I have tested the patchset on mobile platform (exynos4210-trats) and it
      saves 3272 string allocations.  Since minimal allocation is 32 or 64
      bytes depending on Kconfig options the patchset saves respectively about
      100KB or 200KB of memory.
      
      Stats from tested platform show that the main offender is sysfs:
      
      By caller:
        2260 __kernfs_new_node
          631 clk_register+0xc8/0x1b8
          318 clk_register+0x34/0x1b8
            51 kmem_cache_create
            12 alloc_vfsmnt
      
      By string (with count >= 5):
          883 power
          876 subsystem
          135 parameters
          132 device
           61 iommu_group
          ...
      
      This patch (of 5):
      
      Add an alternative version of kstrdup which returns pointer to constant
      char array.  The function checks if input string is in persistent and
      read-only memory section, if yes it returns the input string, otherwise it
      fallbacks to kstrdup.
      
      kstrdup_const is accompanied by kfree_const performing conditional memory
      deallocation of the string.
      Signed-off-by: NAndrzej Hajda <a.hajda@samsung.com>
      Cc: Marek Szyprowski <m.szyprowski@samsung.com>
      Cc: Kyungmin Park <kyungmin.park@samsung.com>
      Cc: Mike Turquette <mturquette@linaro.org>
      Cc: Alexander Viro <viro@zeniv.linux.org.uk>
      Cc: Christoph Lameter <cl@linux.com>
      Cc: Pekka Enberg <penberg@kernel.org>
      Cc: David Rientjes <rientjes@google.com>
      Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
      Cc: Tejun Heo <tj@kernel.org>
      Cc: Greg KH <greg@kroah.com>
      Cc: Geert Uytterhoeven <geert@linux-m68k.org>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      a4bb1e43
  21. 13 2月, 2015 1 次提交
  22. 17 10月, 2014 1 次提交
    • D
      random: add and use memzero_explicit() for clearing data · d4c5efdb
      Daniel Borkmann 提交于
      zatimend has reported that in his environment (3.16/gcc4.8.3/corei7)
      memset() calls which clear out sensitive data in extract_{buf,entropy,
      entropy_user}() in random driver are being optimized away by gcc.
      
      Add a helper memzero_explicit() (similarly as explicit_bzero() variants)
      that can be used in such cases where a variable with sensitive data is
      being cleared out in the end. Other use cases might also be in crypto
      code. [ I have put this into lib/string.c though, as it's always built-in
      and doesn't need any dependencies then. ]
      
      Fixes kernel bugzilla: 82041
      
      Reported-by: zatimend@hotmail.co.uk
      Signed-off-by: NDaniel Borkmann <dborkman@redhat.com>
      Acked-by: NHannes Frederic Sowa <hannes@stressinduktion.org>
      Cc: Alexey Dobriyan <adobriyan@gmail.com>
      Signed-off-by: NTheodore Ts'o <tytso@mit.edu>
      Cc: stable@vger.kernel.org
      d4c5efdb
  23. 14 10月, 2014 1 次提交
  24. 23 5月, 2014 1 次提交
    • G
      lib: add glibc style strchrnul() variant · 11d200e9
      Grant Likely 提交于
      The strchrnul() variant helpfully returns a the end of the string
      instead of a NULL if the requested character is not found. This can
      simplify string parsing code since it doesn't need to expicitly check
      for a NULL return. If a valid string pointer is passed in, then a valid
      null terminated string will always come back out.
      Signed-off-by: NGrant Likely <grant.likely@linaro.org>
      11d200e9
  25. 18 12月, 2012 1 次提交
  26. 13 10月, 2012 1 次提交
  27. 22 8月, 2012 1 次提交
  28. 31 7月, 2012 1 次提交
    • A
      string: introduce memweight() · 639b9e34
      Akinobu Mita 提交于
      memweight() is the function that counts the total number of bits set in
      memory area.  Unlike bitmap_weight(), memweight() takes pointer and size
      in bytes to specify a memory area which does not need to be aligned to
      long-word boundary.
      
      [akpm@linux-foundation.org: rename `w' to `ret']
      Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
      Cc: Anders Larsen <al@alarsen.net>
      Cc: Alasdair Kergon <agk@redhat.com>
      Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
      Cc: Mark Fasheh <mfasheh@suse.com>
      Cc: Joel Becker <jlbec@evilplan.org>
      Cc: Jan Kara <jack@suse.cz>
      Cc: Andreas Dilger <adilger.kernel@dilger.ca>
      Cc: "Theodore Ts'o" <tytso@mit.edu>
      Cc: Matthew Wilcox <matthew@wil.cx>
      Cc: Mauro Carvalho Chehab <mchehab@infradead.org>
      Cc: Tony Luck <tony.luck@gmail.com>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      639b9e34
  29. 01 11月, 2011 1 次提交
  30. 19 5月, 2011 1 次提交
  31. 26 4月, 2011 1 次提交
  32. 15 1月, 2010 1 次提交
  33. 16 12月, 2009 2 次提交
  34. 29 10月, 2009 1 次提交
  35. 01 4月, 2009 1 次提交
    • L
      memdup_user(): introduce · 610a77e0
      Li Zefan 提交于
      I notice there are many places doing copy_from_user() which follows
      kmalloc():
      
              dst = kmalloc(len, GFP_KERNEL);
              if (!dst)
                      return -ENOMEM;
              if (copy_from_user(dst, src, len)) {
      		kfree(dst);
      		return -EFAULT
      	}
      
      memdup_user() is a wrapper of the above code.  With this new function, we
      don't have to write 'len' twice, which can lead to typos/mistakes.  It
      also produces smaller code and kernel text.
      
      A quick grep shows 250+ places where memdup_user() *may* be used.  I'll
      prepare a patchset to do this conversion.
      Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com>
      Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Cc: Americo Wang <xiyou.wangcong@gmail.com>
      Cc: Alexey Dobriyan <adobriyan@gmail.com>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      610a77e0
  36. 31 3月, 2009 1 次提交
  37. 07 3月, 2009 1 次提交
  38. 03 11月, 2008 1 次提交