1. 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
      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: 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>
  2. 04 Oct, 2017 1 commit
  3. 09 Sep, 2017 1 commit
    • Matthew Wilcox's avatar
      alpha: add support for memset16 · 92ce4c3e
      Matthew Wilcox authored
      Alpha already had an optimised fill-memory-with-16-bit-quantity
      assembler routine called memsetw().  It has a slightly different calling
      convention from memset16() in that it takes a byte count, not a count of
      words.  That's the same convention used by ARM's __memset routines, so
      rename Alpha's routine to match and add a memset16() wrapper around it.
      Then convert Alpha's scr_memsetw() to call memset16() instead of
      Link: http://lkml.kernel.org/r/20170720184539.31609-6-willy@infradead.orgSigned-off-by: default avatarMatthew Wilcox <mawilcox@microsoft.com>
      Cc: Richard Henderson <rth@twiddle.net>
      Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
      Cc: Matt Turner <mattst88@gmail.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: Michael Ellerman <mpe@ellerman.id.au>
      Cc: Minchan Kim <minchan@kernel.org>
      Cc: Ralf Baechle <ralf@linux-mips.org>
      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: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
  4. 07 Sep, 2017 2 commits
    • 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
      This is similar to the OpenBSD minherit syscall with MAP_INHERIT_ZERO:
      [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.comSigned-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>
    • 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.comSigned-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>
  5. 04 Sep, 2017 10 commits
  6. 29 Aug, 2017 8 commits
  7. 25 Aug, 2017 1 commit
    • Jiri Slaby's avatar
      futex: Remove duplicated code and fix undefined behaviour · 30d6e0a4
      Jiri Slaby authored
      There is code duplicated over all architecture's headers for
      futex_atomic_op_inuser. Namely op decoding, access_ok check for uaddr,
      and comparison of the result.
      Remove this duplication and leave up to the arches only the needed
      assembly which is now in arch_futex_atomic_op_inuser.
      This effectively distributes the Will Deacon's arm64 fix for undefined
      behaviour reported by UBSAN to all architectures. The fix was done in
      commit 5f16a046 (arm64: futex: Fix undefined behaviour with
      FUTEX_OP_OPARG_SHIFT usage). Look there for an example dump.
      And as suggested by Thomas, check for negative oparg too, because it was
      also reported to cause undefined behaviour report.
      Note that s390 removed access_ok check in d12a2970 ("s390/uaccess:
      remove pointless access_ok() checks") as access_ok there returns true.
      We introduce it back to the helper for the sake of simplicity (it gets
      optimized away anyway).
      Signed-off-by: default avatarJiri Slaby <jslaby@suse.cz>
      Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
      Acked-by: default avatarRussell King <rmk+kernel@armlinux.org.uk>
      Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
      Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com> [s390]
      Acked-by: Chris Metcalf <cmetcalf@mellanox.com> [for tile]
      Reviewed-by: default avatarDarren Hart (VMware) <dvhart@infradead.org>
      Reviewed-by: Will Deacon <will.deacon@arm.com> [core/arm64]
      Cc: linux-mips@linux-mips.org
      Cc: Rich Felker <dalias@libc.org>
      Cc: linux-ia64@vger.kernel.org
      Cc: linux-sh@vger.kernel.org
      Cc: peterz@infradead.org
      Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
      Cc: Max Filippov <jcmvbkbc@gmail.com>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: sparclinux@vger.kernel.org
      Cc: Jonas Bonn <jonas@southpole.se>
      Cc: linux-s390@vger.kernel.org
      Cc: linux-arch@vger.kernel.org
      Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
      Cc: linux-hexagon@vger.kernel.org
      Cc: Helge Deller <deller@gmx.de>
      Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
      Cc: Catalin Marinas <catalin.marinas@arm.com>
      Cc: Matt Turner <mattst88@gmail.com>
      Cc: linux-snps-arc@lists.infradead.org
      Cc: Fenghua Yu <fenghua.yu@intel.com>
      Cc: Arnd Bergmann <arnd@arndb.de>
      Cc: linux-xtensa@linux-xtensa.org
      Cc: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
      Cc: openrisc@lists.librecores.org
      Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
      Cc: Stafford Horne <shorne@gmail.com>
      Cc: linux-arm-kernel@lists.infradead.org
      Cc: Richard Henderson <rth@twiddle.net>
      Cc: Chris Zankel <chris@zankel.net>
      Cc: Michal Simek <monstr@monstr.eu>
      Cc: Tony Luck <tony.luck@intel.com>
      Cc: linux-parisc@vger.kernel.org
      Cc: Vineet Gupta <vgupta@synopsys.com>
      Cc: Ralf Baechle <ralf@linux-mips.org>
      Cc: Richard Kuo <rkuo@codeaurora.org>
      Cc: linux-alpha@vger.kernel.org
      Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
      Cc: linuxppc-dev@lists.ozlabs.org
      Cc: "David S. Miller" <davem@davemloft.net>
      Link: http://lkml.kernel.org/r/20170824073105.3901-1-jslaby@suse.cz
  8. 17 Aug, 2017 1 commit
  9. 04 Aug, 2017 1 commit
  10. 03 Aug, 2017 1 commit
    • Lorenzo Pieralisi's avatar
      alpha/PCI: Replace pci_fixup_irqs() call with host bridge IRQ mapping hooks · 0e4c2eeb
      Lorenzo Pieralisi authored
      The pci_fixup_irqs() function allocates IRQs for all PCI devices present in
      a system; those PCI devices possibly belong to different PCI bus trees (and
      possibly rooted at different host bridges) and may well be enabled (ie
      probed and bound to a driver) by the time pci_fixup_irqs() is called when
      probing a given host bridge driver.
      Furthermore, current kernel code relying on pci_fixup_irqs() to assign
      legacy PCI IRQs to devices does not work at all for hotplugged devices in
      that the code carrying out the IRQ fixup is called at host bridge driver
      probe time, which just cannot take into account devices hotplugged after
      the system has booted.
      The introduction of map/swizzle function hooks in struct pci_host_bridge
      allows us to define per-bridge map/swizzle functions that can be used at
      device probe time in PCI core code to allocate IRQs for a given device
      (through pci_assign_irq()).
      Convert PCI host bridge initialization code to the
      pci_scan_root_bus_bridge() API (that allows to pass a struct
      pci_host_bridge with initialized map/swizzle pointers) and remove the
      pci_fixup_irqs() call from arch code.
      Signed-off-by: default avatarLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
      Signed-off-by: default avatarBjorn Helgaas <bhelgaas@google.com>
      Cc: Richard Henderson <rth@twiddle.net>
      Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
  11. 24 Jul, 2017 1 commit
    • 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:
      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
      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
      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
      Ref: 2.4.0-test1
      Signed-off-by: default avatar"Eric W. Biederman" <ebiederm@xmission.com>
  12. 20 Jul, 2017 1 commit
    • Eric W. Biederman's avatar
      signal/alpha: Document a conflict with SI_USER for SIGTRAP · e2bd64d9
      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.
      Given that alpha is on it's last legs I don't know that it is worth
      fixing this, but it is worth documenting what is going on so that
      no one decides to copy this bad decision.
      This was introduced during the 2.5 development cycle so this
      mess has had a long time for people to be able to depend upon it.
      v2: Added FPE_FIXME for alpha as Helge Deller <deller@gmx.de> pointed out
          with his alternate patch one of the cases is SIGFPE not SIGTRAP.
      Cc: Helge Deller <deller@gmx.de>
      Cc: Richard Henderson <rth@twiddle.net>
      Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
      Cc: Matt Turner <mattst88@gmail.com>
      Cc: linux-alpha@vger.kernel.org
      Acked-by: default avatarRichard Henderson <rth@twiddle.net>
      History Tree: https://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git
      Ref: 0a635c7a84cf ("Fill in siginfo_t.")
      Signed-off-by: default avatar"Eric W. Biederman" <ebiederm@xmission.com>
  13. 17 Jul, 2017 1 commit
  14. 21 Jun, 2017 1 commit
    • David Herrmann's avatar
      net: introduce SO_PEERGROUPS getsockopt · 28b5ba2a
      David Herrmann 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
      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
      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>
  15. 09 Jun, 2017 1 commit
    • 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>
  16. 27 May, 2017 4 commits
  17. 22 May, 2017 1 commit
  18. 21 May, 2017 2 commits
  19. 16 May, 2017 1 commit