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  1. Jan 17, 2019
    • David Rheinsberg's avatar
      net: introduce SO_BINDTOIFINDEX sockopt · f5dd3d0c
      David Rheinsberg authored
      
      
      This introduces a new generic SOL_SOCKET-level socket option called
      SO_BINDTOIFINDEX. It behaves similar to SO_BINDTODEVICE, but takes a
      network interface index as argument, rather than the network interface
      name.
      
      User-space often refers to network-interfaces via their index, but has
      to temporarily resolve it to a name for a call into SO_BINDTODEVICE.
      This might pose problems when the network-device is renamed
      asynchronously by other parts of the system. When this happens, the
      SO_BINDTODEVICE might either fail, or worse, it might bind to the wrong
      device.
      
      In most cases user-space only ever operates on devices which they
      either manage themselves, or otherwise have a guarantee that the device
      name will not change (e.g., devices that are UP cannot be renamed).
      However, particularly in libraries this guarantee is non-obvious and it
      would be nice if that race-condition would simply not exist. It would
      make it easier for those libraries to operate even in situations where
      the device-name might change under the hood.
      
      A real use-case that we recently hit is trying to start the network
      stack early in the initrd but make it survive into the real system.
      Existing distributions rename network-interfaces during the transition
      from initrd into the real system. This, obviously, cannot affect
      devices that are up and running (unless you also consider moving them
      between network-namespaces). However, the network manager now has to
      make sure its management engine for dormant devices will not run in
      parallel to these renames. Particularly, when you offload operations
      like DHCP into separate processes, these might setup their sockets
      early, and thus have to resolve the device-name possibly running into
      this race-condition.
      
      By avoiding a call to resolve the device-name, we no longer depend on
      the name and can run network setup of dormant devices in parallel to
      the transition off the initrd. The SO_BINDTOIFINDEX ioctl plugs this
      race.
      
      Reviewed-by: default avatarTom Gundersen <teg@jklm.no>
      Signed-off-by: default avatarDavid Herrmann <dh.herrmann@gmail.com>
      Acked-by: default avatarWillem de Bruijn <willemb@google.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      f5dd3d0c
  2. Jan 06, 2019
  3. Dec 14, 2018
    • Firoz Khan's avatar
      mips: generate uapi header and system call table files · 99bf73eb
      Firoz Khan authored
      
      
      System call table generation script must be run to gener-
      ate unistd_(nr_)n64/n32/o32.h and syscall_table_32_o32/
      64_n64/64_n32/64-o32.h files. This patch will have changes
      which will invokes the script.
      
      This patch will generate unistd_(nr_)n64/n32/o32.h and
      syscall_table_32_o32/64_n64/64-n32/64-o32.h files by the
      syscall table generation script invoked by parisc/Make-
      file and the generated files against the removed files
      must be identical.
      
      The generated uapi header file will be included in uapi/-
      asm/unistd.h and generated system call table header file
      will be included by kernel/scall32-o32/64-n64/64-n32/-
      64-o32.Sfile.
      
      Signed-off-by: default avatarFiroz Khan <firoz.khan@linaro.org>
      Signed-off-by: default avatarPaul Burton <paul.burton@mips.com>
      Cc: linux-mips@vger.kernel.org
      Cc: Ralf Baechle <ralf@linux-mips.org>
      Cc: James Hogan <jhogan@kernel.org>
      Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
      Cc: Philippe Ombredanne <pombredanne@nexb.com>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Kate Stewart <kstewart@linuxfoundation.org>
      Cc: y2038@lists.linaro.org
      Cc: linux-kernel@vger.kernel.org
      Cc: linux-arch@vger.kernel.org
      Cc: arnd@arndb.de
      Cc: deepa.kernel@gmail.com
      Cc: marcin.juszkiewicz@linaro.org
      99bf73eb
    • Firoz Khan's avatar
      mips: add +1 to __NR_syscalls in uapi header · be856439
      Firoz Khan authored
      
      
      All other architectures are hold a value for __NR_syscalls will
      be equal to the last system call number +1.
      
      But in mips architecture, __NR_syscalls hold the value equal to
      total number of system exits in the architecture. One of the
      patch in this patch series will genarate uapi header files.
      
      In order to make the implementation common across all architect-
      ures, add +1 to __NR_syscalls, which will be equal to the last
      system call number +1.
      
      Signed-off-by: default avatarFiroz Khan <firoz.khan@linaro.org>
      Signed-off-by: default avatarPaul Burton <paul.burton@mips.com>
      Cc: linux-mips@vger.kernel.org
      Cc: Ralf Baechle <ralf@linux-mips.org>
      Cc: James Hogan <jhogan@kernel.org>
      Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
      Cc: Philippe Ombredanne <pombredanne@nexb.com>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Kate Stewart <kstewart@linuxfoundation.org>
      Cc: y2038@lists.linaro.org
      Cc: linux-kernel@vger.kernel.org
      Cc: linux-arch@vger.kernel.org
      Cc: arnd@arndb.de
      Cc: deepa.kernel@gmail.com
      Cc: marcin.juszkiewicz@linaro.org
      be856439
    • Firoz Khan's avatar
      mips: remove unused macros · a5ee2be9
      Firoz Khan authored
      
      
      Remove __NR_Linux_syscalls from uapi/asm/unistd.h as
      there is no users to use NR_syscalls macro in mips
      kernel.
      
      MAX_SYSCALL_NO can also remove as there is commit
      2957c9e6 ("[MIPS] IRIX: Goodbye and thanks for
      all the fish"), eight years ago.
      
      Signed-off-by: default avatarFiroz Khan <firoz.khan@linaro.org>
      [paul.burton@mips.com:
       - Drop the removal of NR_syscalls which is used by
         kernel/trace/trace.h.]
      Signed-off-by: default avatarPaul Burton <paul.burton@mips.com>
      Cc: linux-mips@vger.kernel.org
      Cc: Ralf Baechle <ralf@linux-mips.org>
      Cc: James Hogan <jhogan@kernel.org>
      Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
      Cc: Philippe Ombredanne <pombredanne@nexb.com>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Kate Stewart <kstewart@linuxfoundation.org>
      Cc: y2038@lists.linaro.org
      Cc: linux-kernel@vger.kernel.org
      Cc: linux-arch@vger.kernel.org
      Cc: arnd@arndb.de
      Cc: deepa.kernel@gmail.com
      Cc: marcin.juszkiewicz@linaro.org
      a5ee2be9
  4. Dec 13, 2018
    • Firoz Khan's avatar
      mips: add __NR_syscalls along with __NR_Linux_syscalls · ef2512c8
      Firoz Khan authored
      
      
      __NR_Linux_syscalls macro holds the number of system call
      exist in mips architecture. We have to change the value of
      __NR_Linux_syscalls, if we add or delete a system call.
      
      One of the patch in this patch series has a script which
      will generate a uapi header based on syscall.tbl file.
      The syscall.tbl file contains the total number of system
      calls information. So we have two option to update __NR-
      _Linux_syscalls value.
      
      1. Update __NR_Linux_syscalls in asm/unistd.h manually
         by counting the no.of system calls. No need to update
         __NR_Linux_syscalls until we either add a new system
         call or delete existing system call.
      
      2. We can keep this feature it above mentioned script,
         that will count the number of syscalls and keep it in
         a generated file. In this case we don't need to expli-
         citly update __NR_Linux_syscalls in asm/unistd.h file.
      
      The 2nd option will be the recommended one. For that, I
      added the __NR_syscalls macro in uapi/asm/unistd.h along
      with __NR_Linux_syscalls. The macro __NR_syscalls also
      added for making the name convention same across all
      architecture. While __NR_syscalls isn't strictly part of
      the uapi, having it as part of the generated header to
      simplifies the implementation. We also need to enclose
      this macro with #ifdef __KERNEL__ to avoid side effects.
      
      Signed-off-by: default avatarFiroz Khan <firoz.khan@linaro.org>
      Signed-off-by: default avatarPaul Burton <paul.burton@mips.com>
      Cc: linux-mips@vger.kernel.org
      Cc: Ralf Baechle <ralf@linux-mips.org>
      Cc: James Hogan <jhogan@kernel.org>
      Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
      Cc: Philippe Ombredanne <pombredanne@nexb.com>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Kate Stewart <kstewart@linuxfoundation.org>
      Cc: y2038@lists.linaro.org
      Cc: linux-kernel@vger.kernel.org
      Cc: linux-arch@vger.kernel.org
      Cc: arnd@arndb.de
      Cc: deepa.kernel@gmail.com
      Cc: marcin.juszkiewicz@linaro.org
      ef2512c8
  5. Dec 07, 2018
  6. Nov 19, 2018
  7. Oct 03, 2018
  8. Oct 02, 2018
  9. Jul 04, 2018
  10. Jun 20, 2018
  11. Apr 20, 2018
    • Arnd Bergmann's avatar
      y2038: mips: Extend sysvipc data structures · 3f3a4b3f
      Arnd Bergmann authored
      
      
      MIPS is the weirdest case for sysvipc, because each of the
      three data structures is done differently:
      
      * msqid64_ds has padding in the right place so we could in theory
        extend this one to just have 64-bit values instead of time_t.
        As this does not work for most of the other combinations,
        we just handle it in the common manner though.
      
      * semid64_ds has no padding for 64-bit time_t, but has two reserved
        'long' fields, which are sufficient to extend the sem_otime
        and sem_ctime fields to 64 bit. In order to do this, the libc
        implementation will have to copy the data into another structure
        that has the fields in a different order. MIPS is the only
        architecture with this problem, so this is best done in MIPS
        specific libc code.
      
      * shmid64_ds is slightly worse than that, because it has three
        time_t fields but only two unused 32-bit words. As a workaround,
        we extend each field only by 16 bits, ending up with 48-bit
        timestamps that user space again has to work around by itself.
      
      The compat versions of the data structures are changed in the
      same way.
      
      Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
      3f3a4b3f
  12. Apr 11, 2018
    • Michal Hocko's avatar
      mm: introduce MAP_FIXED_NOREPLACE · a4ff8e86
      Michal Hocko authored
      Patch series "mm: introduce MAP_FIXED_NOREPLACE", v2.
      
      This has started as a follow up discussion [3][4] resulting in the
      runtime failure caused by hardening patch [5] which removes MAP_FIXED
      from the elf loader because MAP_FIXED is inherently dangerous as it
      might silently clobber an existing underlying mapping (e.g.  stack).
      The reason for the failure is that some architectures enforce an
      alignment for the given address hint without MAP_FIXED used (e.g.  for
      shared or file backed mappings).
      
      One way around this would be excluding those archs which do alignment
      tricks from the hardening [6].  The patch is really trivial but it has
      been objected, rightfully so, that this screams for a more generic
      solution.  We basically want a non-destructive MAP_FIXED.
      
      The first patch introduced MAP_FIXED_NOREPLACE which enforces the given
      address but unlike MAP_FIXED it fails with EEXIST if the given range
      conflicts with an existing one.  The flag is introduced as a completely
      new one rather than a MAP_FIXED extension because of the backward
      compatibility.  We really want a never-clobber semantic even on older
      kernels which do not recognize the flag.  Unfortunately mmap sucks
      wrt flags evaluation because we do not EINVAL on unknown flags.  On
      those kernels we would simply use the traditional hint based semantic so
      the caller can still get a different address (which sucks) but at least
      not silently corrupt an existing mapping.  I do not see a good way
      around that.  Except we won't export expose the new semantic to the
      userspace at all.
      
      It seems there are users who would like to have something like that.
      Jemalloc has been mentioned by Michael Ellerman [7]
      
      Florian Weimer has mentioned the following:
      : glibc ld.so currently maps DSOs without hints.  This means that the kernel
      : will map right next to each other, and the offsets between them a completely
      : predictable.  We would like to change that and supply a random address in a
      : window of the address space.  If there is a conflict, we do not want the
      : kernel to pick a non-random address. Instead, we would try again with a
      : random address.
      
      John Hubbard has mentioned CUDA example
      : a) Searches /proc/<pid>/maps for a "suitable" region of available
      : VA space.  "Suitable" generally means it has to have a base address
      : within a certain limited range (a particular device model might
      : have odd limitations, for example), it has to be large enough, and
      : alignment has to be large enough (again, various devices may have
      : constraints that lead us to do this).
      :
      : This is of course subject to races with other threads in the process.
      :
      : Let's say it finds a region starting at va.
      :
      : b) Next it does:
      :     p = mmap(va, ...)
      :
      : *without* setting MAP_FIXED, of course (so va is just a hint), to
      : attempt to safely reserve that region. If p != va, then in most cases,
      : this is a failure (almost certainly due to another thread getting a
      : mapping from that region before we did), and so this layer now has to
      : call munmap(), before returning a "failure: retry" to upper layers.
      :
      :     IMPROVEMENT: --> if instead, we could call this:
      :
      :             p = mmap(va, ... MAP_FIXED_NOREPLACE ...)
      :
      :         , then we could skip the munmap() call upon failure. This
      :         is a small thing, but it is useful here. (Thanks to Piotr
      :         Jaroszynski and Mark Hairgrove for helping me get that detail
      :         exactly right, btw.)
      :
      : c) After that, CUDA suballocates from p, via:
      :
      :      q = mmap(sub_region_start, ... MAP_FIXED ...)
      :
      : Interestingly enough, "freeing" is also done via MAP_FIXED, and
      : setting PROT_NONE to the subregion. Anyway, I just included (c) for
      : general interest.
      
      Atomic address range probing in the multithreaded programs in general
      sounds like an interesting thing to me.
      
      The second patch simply replaces MAP_FIXED use in elf loader by
      MAP_FIXED_NOREPLACE.  I believe other places which rely on MAP_FIXED
      should follow.  Actually real MAP_FIXED usages should be docummented
      properly and they should be more of an exception.
      
      [1] http://lkml.kernel.org/r/20171116101900.13621-1-mhocko@kernel.org
      [2] http://lkml.kernel.org/r/20171129144219.22867-1-mhocko@kernel.org
      [3] http://lkml.kernel.org/r/20171107162217.382cd754@canb.auug.org.au
      [4] http://lkml.kernel.org/r/1510048229.12079.7.camel@abdul.in.ibm.com
      [5] http://lkml.kernel.org/r/20171023082608.6167-1-mhocko@kernel.org
      [6] http://lkml.kernel.org/r/20171113094203.aofz2e7kueitk55y@dhcp22.suse.cz
      [7] http://lkml.kernel.org/r/87efp1w7vy.fsf@concordia.ellerman.id.au
      
      This patch (of 2):
      
      MAP_FIXED is used quite often to enforce mapping at the particular range.
      The main problem of this flag is, however, that it is inherently dangerous
      because it unmaps existing mappings covered by the requested range.  This
      can cause silent memory corruptions.  Some of them even with serious
      security implications.  While the current semantic might be really
      desiderable in many cases there are others which would want to enforce the
      given range but rather see a failure than a silent memory corruption on a
      clashing range.  Please note that there is no guarantee that a given range
      is obeyed by the mmap even when it is free - e.g.  arch specific code is
      allowed to apply an alignment.
      
      Introduce a new MAP_FIXED_NOREPLACE flag for mmap to achieve this
      behavior.  It has the same semantic as MAP_FIXED wrt.  the given address
      request with a single exception that it fails with EEXIST if the requested
      address is already covered by an existing mapping.  We still do rely on
      get_unmaped_area to handle all the arch specific MAP_FIXED treatment and
      check for a conflicting vma after it returns.
      
      The flag is introduced as a completely new one rather than a MAP_FIXED
      extension because of the backward compatibility.  We really want a
      never-clobber semantic even on older kernels which do not recognize the
      flag.  Unfortunately mmap sucks wrt.  flags evaluation because we do not
      EINVAL on unknown flags.  On those kernels we would simply use the
      traditional hint based semantic so the caller can still get a different
      address (which sucks) but at least not silently corrupt an existing
      mapping.  I do not see a good way around that.
      
      [mpe@ellerman.id.au: fix whitespace]
      [fail on clashing range with EEXIST as per Florian Weimer]
      [set MAP_FIXED before round_hint_to_min as per Khalid Aziz]
      Link: http://lkml.kernel.org/r/20171213092550.2774-2-mhocko@kernel.org
      
      
      Reviewed-by: default avatarKhalid Aziz <khalid.aziz@oracle.com>
      Signed-off-by: default avatarMichal Hocko <mhocko@suse.com>
      Acked-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
      Cc: Khalid Aziz <khalid.aziz@oracle.com>
      Cc: Russell King - ARM Linux <linux@armlinux.org.uk>
      Cc: Andrea Arcangeli <aarcange@redhat.com>
      Cc: Florian Weimer <fweimer@redhat.com>
      Cc: John Hubbard <jhubbard@nvidia.com>
      Cc: Matthew Wilcox <willy@infradead.org>
      Cc: Abdul Haleem <abdhalee@linux.vnet.ibm.com>
      Cc: Joel Stanley <joel@jms.id.au>
      Cc: Kees Cook <keescook@chromium.org>
      Cc: Michal Hocko <mhocko@suse.com>
      Cc: Jason Evans <jasone@google.com>
      Cc: David Goldblatt <davidtgoldblatt@gmail.com>
      Cc: Edward Tomasz Napierała <trasz@FreeBSD.org>
      Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      a4ff8e86
  13. Feb 19, 2018
  14. Feb 11, 2018
    • Al Viro's avatar
      unify {de,}mangle_poll(), get rid of kernel-side POLL... · 7a163b21
      Al Viro authored
      
      
      except, again, POLLFREE and POLL_BUSY_LOOP.
      
      With this, we finally get to the promised end result:
      
       - POLL{IN,OUT,...} are plain integers and *not* in __poll_t, so any
         stray instances of ->poll() still using those will be caught by
         sparse.
      
       - eventpoll.c and select.c warning-free wrt __poll_t
      
       - no more kernel-side definitions of POLL... - userland ones are
         visible through the entire kernel (and used pretty much only for
         mangle/demangle)
      
       - same behavior as after the first series (i.e. sparc et.al. epoll(2)
         working correctly).
      
      Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      7a163b21
  15. Jan 12, 2018
  16. Dec 05, 2017
    • Hendrik Brueckner's avatar
      bpf: correct broken uapi for BPF_PROG_TYPE_PERF_EVENT program type · c895f6f7
      Hendrik Brueckner authored
      
      
      Commit 0515e599 ("bpf: introduce BPF_PROG_TYPE_PERF_EVENT
      program type") introduced the bpf_perf_event_data structure which
      exports the pt_regs structure.  This is OK for multiple architectures
      but fail for s390 and arm64 which do not export pt_regs.  Programs
      using them, for example, the bpf selftest fail to compile on these
      architectures.
      
      For s390, exporting the pt_regs is not an option because s390 wants
      to allow changes to it.  For arm64, there is a user_pt_regs structure
      that covers parts of the pt_regs structure for use by user space.
      
      To solve the broken uapi for s390 and arm64, introduce an abstract
      type for pt_regs and add an asm/bpf_perf_event.h file that concretes
      the type.  An asm-generic header file covers the architectures that
      export pt_regs today.
      
      The arch-specific enablement for s390 and arm64 follows in separate
      commits.
      
      Reported-by: default avatarThomas Richter <tmricht@linux.vnet.ibm.com>
      Fixes: 0515e599 ("bpf: int...
      c895f6f7
  17. Nov 30, 2017
  18. Nov 27, 2017
  19. Nov 03, 2017
    • Dan Williams's avatar
      mm: introduce MAP_SHARED_VALIDATE, a mechanism to safely define new mmap flags · 1c972597
      Dan Williams authored
      
      
      The mmap(2) syscall suffers from the ABI anti-pattern of not validating
      unknown flags. However, proposals like MAP_SYNC need a mechanism to
      define new behavior that is known to fail on older kernels without the
      support. Define a new MAP_SHARED_VALIDATE flag pattern that is
      guaranteed to fail on all legacy mmap implementations.
      
      It is worth noting that the original proposal was for a standalone
      MAP_VALIDATE flag. However, when that  could not be supported by all
      archs Linus observed:
      
          I see why you *think* you want a bitmap. You think you want
          a bitmap because you want to make MAP_VALIDATE be part of MAP_SYNC
          etc, so that people can do
      
          ret = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED
      		    | MAP_SYNC, fd, 0);
      
          and "know" that MAP_SYNC actually takes.
      
          And I'm saying that whole wish is bogus. You're fundamentally
          depending on special semantics, just make it explicit. It's already
          not portable, so don't try to make it so.
      
          Rename that MAP_VALIDATE as MAP_SHARED_VALIDATE, make it have a value
          of 0x3, and make people do
      
          ret = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED_VALIDATE
      		    | MAP_SYNC, fd, 0);
      
          and then the kernel side is easier too (none of that random garbage
          playing games with looking at the "MAP_VALIDATE bit", but just another
          case statement in that map type thing.
      
          Boom. Done.
      
      Similar to ->fallocate() we also want the ability to validate the
      support for new flags on a per ->mmap() 'struct file_operations'
      instance basis.  Towards that end arrange for flags to be generically
      validated against a mmap_supported_flags exported by 'struct
      file_operations'. By default all existing flags are implicitly
      supported, but new flags require MAP_SHARED_VALIDATE and
      per-instance-opt-in.
      
      Cc: Jan Kara <jack@suse.cz>
      Cc: Arnd Bergmann <arnd@arndb.de>
      Cc: Andy Lutomirski <luto@kernel.org>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Suggested-by: default avatarChristoph Hellwig <hch@lst.de>
      Suggested-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      Reviewed-by: default avatarRoss Zwisler <ross.zwisler@linux.intel.com>
      Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
      Signed-off-by: default avatarJan Kara <jack@suse.cz>
      Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
      1c972597
  20. Nov 02, 2017
    • Greg Kroah-Hartman's avatar
      License cleanup: add SPDX license identifier to uapi header files with a license · e2be04c7
      Greg Kroah-Hartman authored
      
      
      Many user space API headers have licensing information, which is either
      incomplete, badly formatted or just a shorthand for referring to the
      license under which the file is supposed to be.  This makes it hard for
      compliance tools to determine the correct license.
      
      Update these files with an SPDX license identifier.  The identifier was
      chosen based on the license information in the file.
      
      GPL/LGPL licensed headers get the matching GPL/LGPL SPDX license
      identifier with the added 'WITH Linux-syscall-note' exception, which is
      the officially assigned exception identifier for the kernel syscall
      exception:
      
         NOTE! This copyright does *not* cover user programs that use kernel
         services by normal system calls - this is merely considered normal use
         of the kernel, and does *not* fall under the heading of "derived work".
      
      This exception makes it possible to include GPL headers into non GPL
      code, without confusing license compliance tools.
      
      Headers which have either explicit dual licensing or are just licensed
      under a non GPL license are updated with the corresponding SPDX
      identifier and the GPLv2 with syscall exception identifier.  The format
      is:
              ((GPL-2.0 WITH Linux-syscall-note) OR SPDX-ID-OF-OTHER-LICENSE)
      
      SPDX license identifiers are a legally binding shorthand, which can be
      used instead of the full boiler plate text.  The update does not remove
      existing license information as this has to be done on a case by case
      basis and the copyright holders might have to be consulted. This will
      happen in a separate step.
      
      This patch is based on work done by Thomas Gleixner and Kate Stewart and
      Philippe Ombredanne.  See the previous patch in this series for the
      methodology of how this patch was researched.
      
      Reviewed-by: default avatarKate Stewart <kstewart@linuxfoundation.org>
      Reviewed-by: default avatarPhilippe Ombredanne <pombredanne@nexb.com>
      Reviewed-by: default avatarThomas Gleixner <tglx@linutronix.de>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      e2be04c7
    • Greg Kroah-Hartman's avatar
      License cleanup: add SPDX license identifier to uapi header files with no license · 6f52b16c
      Greg Kroah-Hartman authored
      
      
      Many user space API headers are missing licensing information, which
      makes it hard for compliance tools to determine the correct license.
      
      By default are files without license information under the default
      license of the kernel, which is GPLV2.  Marking them GPLV2 would exclude
      them from being included in non GPLV2 code, which is obviously not
      intended. The user space API headers fall under the syscall exception
      which is in the kernels COPYING file:
      
         NOTE! This copyright does *not* cover user programs that use kernel
         services by normal system calls - this is merely considered normal use
         of the kernel, and does *not* fall under the heading of "derived work".
      
      otherwise syscall usage would not be possible.
      
      Update the files which contain no license information with an SPDX
      license identifier.  The chosen identifier is 'GPL-2.0 WITH
      Linux-syscall-note' which is the officially assigned identifier for the
      Linux syscall exception.  SPDX license identifiers are 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.  See the previous patch in this series for the
      methodology of how this patch was researched.
      
      Reviewed-by: default avatarKate Stewart <kstewart@linuxfoundation.org>
      Reviewed-by: default avatarPhilippe Ombredanne <pombredanne@nexb.com>
      Reviewed-by: default avatarThomas Gleixner <tglx@linutronix.de>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      6f52b16c
  21. Sep 07, 2017
    • Rik van Riel's avatar
      mm,fork: introduce MADV_WIPEONFORK · d2cd9ede
      Rik van Riel authored
      Introduce MADV_WIPEONFORK semantics, which result in a VMA being empty
      in the child process after fork.  This differs from MADV_DONTFORK in one
      important way.
      
      If a child process accesses memory that was MADV_WIPEONFORK, it will get
      zeroes.  The address ranges are still valid, they are just empty.
      
      If a child process accesses memory that was MADV_DONTFORK, it will get a
      segmentation fault, since those address ranges are no longer valid in
      the child after fork.
      
      Since MADV_DONTFORK also seems to be used to allow very large programs
      to fork in systems with strict memory overcommit restrictions, changing
      the semantics of MADV_DONTFORK might break existing programs.
      
      MADV_WIPEONFORK only works on private, anonymous VMAs.
      
      The use case is libraries that store or cache information, and want to
      know that they need to regenerate it in the child process after fork.
      
      Examples of this would be:
       - systemd/pulseaudio API checks (fail after fork) (replacing a getpid
         check, which is too slow without a PID cache)
       - PKCS#11 API reinitialization check (mandated by specification)
       - glibc's upcoming PRNG (reseed after fork)
       - OpenSSL PRNG (reseed after fork)
      
      The security benefits of a forking server having a re-inialized PRNG in
      every child process are pretty obvious.  However, due to libraries
      having all kinds of internal state, and programs getting compiled with
      many different versions of each library, it is unreasonable to expect
      calling programs to re-initialize everything manually after fork.
      
      A further complication is the proliferation of clone flags, programs
      bypassing glibc's functions to call clone directly, and programs calling
      unshare, causing the glibc pthread_atfork hook to not get called.
      
      It would be better to have the kernel take care of this automatically.
      
      The patch also adds MADV_KEEPONFORK, to undo the effects of a prior
      MADV_WIPEONFORK.
      
      This is similar to the OpenBSD minherit syscall with MAP_INHERIT_ZERO:
      
          https://man.openbsd.org/minherit.2
      
      [akpm@linux-foundation.org: numerically order arch/parisc/include/uapi/asm/mman.h #defines]
      Link: http://lkml.kernel.org/r/20170811212829.29186-3-riel@redhat.com
      
      
      Signed-off-by: default avatarRik van Riel <riel@redhat.com>
      Reported-by: default avatarFlorian Weimer <fweimer@redhat.com>
      Reported-by: default avatarColm MacCártaigh <colm@allcosts.net>
      Reviewed-by: default avatarMike Kravetz <mike.kravetz@oracle.com>
      Cc: "H. Peter Anvin" <hpa@zytor.com>
      Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
      Cc: Andy Lutomirski <luto@amacapital.net>
      Cc: Dave Hansen <dave.hansen@intel.com>
      Cc: Ingo Molnar <mingo@kernel.org>
      Cc: Helge Deller <deller@gmx.de>
      Cc: Kees Cook <keescook@chromium.org>
      Cc: Matthew Wilcox <willy@infradead.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Will Drewry <wad@chromium.org>
      Cc: <linux-api@vger.kernel.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      d2cd9ede
    • Mike Kravetz's avatar
      mm: arch: consolidate mmap hugetlb size encodings · aafd4562
      Mike Kravetz authored
      A non-default huge page size can be encoded in the flags argument of the
      mmap system call.  The definitions for these encodings are in arch
      specific header files.  However, all architectures use the same values.
      
      Consolidate all the definitions in the primary user header file
      (uapi/linux/mman.h).  Include definitions for all known huge page sizes.
      Use the generic encoding definitions in hugetlb_encode.h as the basis
      for these definitions.
      
      Link: http://lkml.kernel.org/r/1501527386-10736-3-git-send-email-mike.kravetz@oracle.com
      
      
      Signed-off-by: default avatarMike Kravetz <mike.kravetz@oracle.com>
      Acked-by: default avatarMichal Hocko <mhocko@suse.com>
      Cc: Andi Kleen <ak@linux.intel.com>
      Cc: Andrea Arcangeli <aarcange@redhat.com>
      Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
      Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
      Cc: Arnd Bergmann <arnd@arndb.de>
      Cc: Davidlohr Bueso <dbueso@suse.de>
      Cc: Matthew Wilcox <willy@infradead.org>
      Cc: Michael Kerrisk <mtk.manpages@gmail.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      aafd4562
  22. Sep 06, 2017
  23. Aug 17, 2017
  24. Aug 04, 2017
  25. Jul 24, 2017
    • Eric W. Biederman's avatar
      signal: Remove kernel interal si_code magic · cc731525
      Eric W. Biederman authored
      
      
      struct siginfo is a union and the kernel since 2.4 has been hiding a union
      tag in the high 16bits of si_code using the values:
      __SI_KILL
      __SI_TIMER
      __SI_POLL
      __SI_FAULT
      __SI_CHLD
      __SI_RT
      __SI_MESGQ
      __SI_SYS
      
      While this looks plausible on the surface, in practice this situation has
      not worked well.
      
      - Injected positive signals are not copied to user space properly
        unless they have these magic high bits set.
      
      - Injected positive signals are not reported properly by signalfd
        unless they have these magic high bits set.
      
      - These kernel internal values leaked to userspace via ptrace_peek_siginfo
      
      - It was possible to inject these kernel internal values and cause the
        the kernel to misbehave.
      
      - Kernel developers got confused and expected these kernel internal values
        in userspace in kernel self tests.
      
      - Kernel developers got confused and set si_code to __SI_FAULT which
        is SI_USER in userspace which causes userspace to think an ordinary user
        sent the signal and that it was not kernel generated.
      
      - The values make it impossible to reorganize the code to transform
        siginfo_copy_to_user into a plain copy_to_user.  As si_code must
        be massaged before being passed to userspace.
      
      So remove these kernel internal si codes and make the kernel code simpler
      and more maintainable.
      
      To replace these kernel internal magic si_codes introduce the helper
      function siginfo_layout, that takes a signal number and an si_code and
      computes which union member of siginfo is being used.  Have
      siginfo_layout return an enumeration so that gcc will have enough
      information to warn if a switch statement does not handle all of union
      members.
      
      A couple of architectures have a messed up ABI that defines signal
      specific duplications of SI_USER which causes more special cases in
      siginfo_layout than I would like.  The good news is only problem
      architectures pay the cost.
      
      Update all of the code that used the previous magic __SI_ values to
      use the new SIL_ values and to call siginfo_layout to get those
      values.  Escept where not all of the cases are handled remove the
      defaults in the switch statements so that if a new case is missed in
      the future the lack will show up at compile time.
      
      Modify the code that copies siginfo si_code to userspace to just copy
      the value and not cast si_code to a short first.  The high bits are no
      longer used to hold a magic union member.
      
      Fixup the siginfo header files to stop including the __SI_ values in
      their constants and for the headers that were missing it to properly
      update the number of si_codes for each signal type.
      
      The fixes to copy_siginfo_from_user32 implementations has the
      interesting property that several of them perviously should never have
      worked as the __SI_ values they depended up where kernel internal.
      With that dependency gone those implementations should work much
      better.
      
      The idea of not passing the __SI_ values out to userspace and then
      not reinserting them has been tested with criu and criu worked without
      changes.
      
      Ref: 2.4.0-test1
      Signed-off-by: default avatar"Eric W. Biederman" <ebiederm@xmission.com>
      cc731525
  26. Jul 20, 2017
    • Eric W. Biederman's avatar
      signal/mips: Document a conflict with SI_USER with SIGFPE · ea1b75cf
      Eric W. Biederman authored
      
      
      Setting si_code to __SI_FAULT results in a userspace seeing
      an si_code of 0.  This is the same si_code as SI_USER.  Posix
      and common sense requires that SI_USER not be a signal specific
      si_code.  As such this use of 0 for the si_code is a pretty
      horribly broken ABI.
      
      This use of of __SI_FAULT is only a decade old.  Which compared
      to the other pieces of kernel code that has made this mistake
      is almost yesterday.
      
      This is probably worth fixing but I don't know mips well enough
      to know what si_code to would be the proper one to use.
      
      Cc: Ralf Baechle <ralf@linux-mips.org>
      Ref: 948a34cf ("[MIPS] Maintain si_code field properly for FP exceptions")
      Signed-off-by: default avatar"Eric W. Biederman" <ebiederm@xmission.com>
      ea1b75cf
  27. Jul 17, 2017
  28. Jun 29, 2017
  29. Jun 28, 2017
  30. Jun 21, 2017
    • David Rheinsberg's avatar
      net: introduce SO_PEERGROUPS getsockopt · 28b5ba2a
      David Rheinsberg authored
      
      
      This adds the new getsockopt(2) option SO_PEERGROUPS on SOL_SOCKET to
      retrieve the auxiliary groups of the remote peer. It is designed to
      naturally extend SO_PEERCRED. That is, the underlying data is from the
      same credentials. Regarding its syntax, it is based on SO_PEERSEC. That
      is, if the provided buffer is too small, ERANGE is returned and @optlen
      is updated. Otherwise, the information is copied, @optlen is set to the
      actual size, and 0 is returned.
      
      While SO_PEERCRED (and thus `struct ucred') already returns the primary
      group, it lacks the auxiliary group vector. However, nearly all access
      controls (including kernel side VFS and SYSVIPC, but also user-space
      polkit, DBus, ...) consider the entire set of groups, rather than just
      the primary group. But this is currently not possible with pure
      SO_PEERCRED. Instead, user-space has to work around this and query the
      system database for the auxiliary groups of a UID retrieved via
      SO_PEERCRED.
      
      Unfortunately, there is no race-free way to query the auxiliary groups
      of the PID/UID retrieved via SO_PEERCRED. Hence, the current user-space
      solution is to use getgrouplist(3p), which itself falls back to NSS and
      whatever is configured in nsswitch.conf(3). This effectively checks
      which groups we *would* assign to the user if it logged in *now*. On
      normal systems it is as easy as reading /etc/group, but with NSS it can
      resort to quering network databases (eg., LDAP), using IPC or network
      communication.
      
      Long story short: Whenever we want to use auxiliary groups for access
      checks on IPC, we need further IPC to talk to the user/group databases,
      rather than just relying on SO_PEERCRED and the incoming socket. This
      is unfortunate, and might even result in dead-locks if the database
      query uses the same IPC as the original request.
      
      So far, those recursions / dead-locks have been avoided by using
      primitive IPC for all crucial NSS modules. However, we want to avoid
      re-inventing the wheel for each NSS module that might be involved in
      user/group queries. Hence, we would preferably make DBus (and other IPC
      that supports access-management based on groups) work without resorting
      to the user/group database. This new SO_PEERGROUPS ioctl would allow us
      to make dbus-daemon work without ever calling into NSS.
      
      Cc: Michal Sekletar <msekleta@redhat.com>
      Cc: Simon McVittie <simon.mcvittie@collabora.co.uk>
      Reviewed-by: default avatarTom Gundersen <teg@jklm.no>
      Signed-off-by: default avatarDavid Herrmann <dh.herrmann@gmail.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      28b5ba2a
  31. Jun 09, 2017
    • Aleksa Sarai's avatar
      tty: add TIOCGPTPEER ioctl · 54ebbfb1
      Aleksa Sarai authored
      
      
      When opening the slave end of a PTY, it is not possible for userspace to
      safely ensure that /dev/pts/$num is actually a slave (in cases where the
      mount namespace in which devpts was mounted is controlled by an
      untrusted process). In addition, there are several unresolvable
      race conditions if userspace were to attempt to detect attacks through
      stat(2) and other similar methods [in addition it is not clear how
      userspace could detect attacks involving FUSE].
      
      Resolve this by providing an interface for userpace to safely open the
      "peer" end of a PTY file descriptor by using the dentry cached by
      devpts. Since it is not possible to have an open master PTY without
      having its slave exposed in /dev/pts this interface is safe. This
      interface currently does not provide a way to get the master pty (since
      it is not clear whether such an interface is safe or even useful).
      
      Cc: Christian Brauner <christian.brauner@ubuntu.com>
      Cc: Valentin Rothberg <vrothberg@suse.com>
      Signed-off-by: default avatarAleksa Sarai <asarai@suse.de>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      54ebbfb1
  32. May 22, 2017
  33. May 10, 2017
    • Nicolas Dichtel's avatar
      uapi: export all headers under uapi directories · fcc8487d
      Nicolas Dichtel authored
      
      
      Regularly, when a new header is created in include/uapi/, the developer
      forgets to add it in the corresponding Kbuild file. This error is usually
      detected after the release is out.
      
      In fact, all headers under uapi directories should be exported, thus it's
      useless to have an exhaustive list.
      
      After this patch, the following files, which were not exported, are now
      exported (with make headers_install_all):
      asm-arc/kvm_para.h
      asm-arc/ucontext.h
      asm-blackfin/shmparam.h
      asm-blackfin/ucontext.h
      asm-c6x/shmparam.h
      asm-c6x/ucontext.h
      asm-cris/kvm_para.h
      asm-h8300/shmparam.h
      asm-h8300/ucontext.h
      asm-hexagon/shmparam.h
      asm-m32r/kvm_para.h
      asm-m68k/kvm_para.h
      asm-m68k/shmparam.h
      asm-metag/kvm_para.h
      asm-metag/shmparam.h
      asm-metag/ucontext.h
      asm-mips/hwcap.h
      asm-mips/reg.h
      asm-mips/ucontext.h
      asm-nios2/kvm_para.h
      asm-nios2/ucontext.h
      asm-openrisc/shmparam.h
      asm-parisc/kvm_para.h
      asm-powerpc/perf_regs.h
      asm-sh/kvm_para.h
      asm-sh/ucontext.h
      asm-tile/shmparam.h
      asm-unicore32/shmparam.h
      asm-unicore32/ucontext.h
      asm-x86/hwcap2.h
      asm-xtensa/kvm_para.h
      drm/armada_drm.h
      drm/etnaviv_drm.h
      drm/vgem_drm.h
      linux/aspeed-lpc-ctrl.h
      linux/auto_dev-ioctl.h
      linux/bcache.h
      linux/btrfs_tree.h
      linux/can/vxcan.h
      linux/cifs/cifs_mount.h
      linux/coresight-stm.h
      linux/cryptouser.h
      linux/fsmap.h
      linux/genwqe/genwqe_card.h
      linux/hash_info.h
      linux/kcm.h
      linux/kcov.h
      linux/kfd_ioctl.h
      linux/lightnvm.h
      linux/module.h
      linux/nbd-netlink.h
      linux/nilfs2_api.h
      linux/nilfs2_ondisk.h
      linux/nsfs.h
      linux/pr.h
      linux/qrtr.h
      linux/rpmsg.h
      linux/sched/types.h
      linux/sed-opal.h
      linux/smc.h
      linux/smc_diag.h
      linux/stm.h
      linux/switchtec_ioctl.h
      linux/vfio_ccw.h
      linux/wil6210_uapi.h
      rdma/bnxt_re-abi.h
      
      Note that I have removed from this list the files which are generated in every
      exported directories (like .install or .install.cmd).
      
      Thanks to Julien Floret <julien.floret@6wind.com> for the tip to get all
      subdirs with a pure makefile command.
      
      For the record, note that exported files for asm directories are a mix of
      files listed by:
       - include/uapi/asm-generic/Kbuild.asm;
       - arch/<arch>/include/uapi/asm/Kbuild;
       - arch/<arch>/include/asm/Kbuild.
      
      Signed-off-by: default avatarNicolas Dichtel <nicolas.dichtel@6wind.com>
      Acked-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
      Acked-by: default avatarRussell King <rmk+kernel@armlinux.org.uk>
      Acked-by: default avatarMark Salter <msalter@redhat.com>
      Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
      Signed-off-by: default avatarMasahiro Yamada <yamada.masahiro@socionext.com>
      fcc8487d
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