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  1. Apr 03, 2016
  2. Mar 29, 2016
    • James Hogan's avatar
      MIPS: cpu_name_string: Use raw_smp_processor_id(). · e95008a1
      James Hogan authored
      
      
      If cpu_name_string() is used in non-atomic context when preemption is
      enabled, it can trigger a BUG such as this one:
      
      BUG: using smp_processor_id() in preemptible [00000000] code: unaligned/156
      caller is __show_regs+0x1e4/0x330
      CPU: 2 PID: 156 Comm: unaligned Tainted: G        W       4.3.0-00366-ga3592179816d-dirty #1501
      Stack : ffffffff80900000 ffffffff8019bc18 000000000000005f ffffffff80a20000
               0000000000000000 0000000000000009 ffffffff8019c0e0 ffffffff80835648
               a8000000ff2bdec0 ffffffff80a1e628 000000000000009c 0000000000000002
               ffffffff80840000 a8000000fff2ffb0 0000000000000020 ffffffff8020e43c
               a8000000fff2fcf8 ffffffff80a20000 0000000000000000 ffffffff808f2607
               ffffffff8082b138 ffffffff8019cd1c 0000000000000030 ffffffff8082b138
               0000000000000002 000000000000009c 0000000000000000 0000000000000000
               0000000000000000 a8000000fff2fc40 0000000000000000 ffffffff8044dbf4
               0000000000000000 0000000000000000 0000000000000000 ffffffff8010c400
               ffffffff80855bb0 ffffffff8010d008 0000000000000000 ffffffff8044dbf4
               ...
      Call Trace:
      [<ffffffff8010d008>] show_stack+0x90/0xb0
      [<ffffffff8044dbf4>] dump_stack+0x84/0xe0
      [<ffffffff8046d4ec>] check_preemption_disabled+0x10c/0x110
      [<ffffffff8010c40c>] __show_regs+0x1e4/0x330
      [<ffffffff8010d060>] show_registers+0x28/0xc0
      [<ffffffff80110748>] do_ade+0xcc8/0xce0
      [<ffffffff80105b84>] resume_userspace_check+0x0/0x10
      
      This is possible because cpu_name_string() is used by __show_regs(),
      which is used by both show_regs() and show_registers(). These two
      functions are used by various exception handling functions, only some of
      which ensure that interrupts or preemption is disabled.
      
      However the following have interrupts explicitly enabled or not
      explicitly disabled:
      - do_reserved() (irqs enabled)
      - do_ade() (irqs not disabled)
      
      This can be hit by setting /sys/kernel/debug/mips/unaligned_action to 2,
      and triggering an address error exception, e.g. an unaligned access or
      access to kernel segment from user mode.
      
      To fix the above cases, use raw_smp_processor_id() instead. It is
      unusual for CPU names to be different in the same system, and even if
      they were, its possible the process has migrated between the exception
      of interest and the cpu_name_string() call anyway.
      
      Signed-off-by: default avatarJames Hogan <james.hogan@imgtec.com>
      Cc: linux-mips@linux-mips.org
      Patchwork: https://patchwork.linux-mips.org/patch/12212/
      
      
      Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
      e95008a1
    • Manuel Lauss's avatar
      pcmcia: db1xxx_ss: fix last irq_to_gpio user · e34b6fcf
      Manuel Lauss authored
      
      
      remove the usage of removed irq_to_gpio() function.  On pre-DB1200
      boards, pass the actual carddetect GPIO number instead of the IRQ,
      because we need the gpio to actually test card status (inserted or
      not) and can get the irq number with gpio_to_irq() instead.
      
      Tested on DB1300 and DB1500, this patch fixes PCMCIA on the DB1500,
      which used irq_to_gpio().
      
      Fixes: 832f5dac ("MIPS: Remove all the uses of custom gpio.h")
      Signed-off-by: default avatarManuel Lauss <manuel.lauss@gmail.com>
      Acked-by: default avatarArnd Bergmann <arnd@arndb.de>
      Reviewed-by: default avatarLinus Walleij <linus.walleij@linaro.org>
      Cc: linux-pcmcia@lists.infradead.org
      Cc: Linux-MIPS <linux-mips@linux-mips.org>
      Cc: stable@vger.kernel.org	# v4.3+
      Patchwork: https://patchwork.linux-mips.org/patch/12747/
      
      
      Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
      e34b6fcf
    • Paul Burton's avatar
      MIPS: Fix MSA ld unaligned failure cases · fa8ff601
      Paul Burton authored
      
      
      Copying the content of an MSA vector from user memory may involve TLB
      faults & mapping in pages. This will fail when preemption is disabled
      due to an inability to acquire mmap_sem from do_page_fault, which meant
      such vector loads to unmapped pages would always fail to be emulated.
      Fix this by disabling preemption later only around the updating of
      vector register state.
      
      This change does however introduce a race between performing the load
      into thread context & the thread being preempted, saving its current
      live context & clobbering the loaded value. This should be a rare
      occureence, so optimise for the fast path by simply repeating the load if
      we are preempted.
      
      Additionally if the copy failed then the failure path was taken with
      preemption left disabled, leading to the kernel typically encountering
      further issues around sleeping whilst atomic. The change to where
      preemption is disabled avoids this issue.
      
      Fixes: e4aa1f15 "MIPS: MSA unaligned memory access support"
      Reported-by: default avatarJames Hogan <james.hogan@imgtec.com>
      Signed-off-by: default avatarPaul Burton <paul.burton@imgtec.com>
      Reviewed-by: default avatarJames Hogan <james.hogan@imgtec.com>
      Cc: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
      Cc: Maciej W. Rozycki <macro@linux-mips.org>
      Cc: James Cowgill <James.Cowgill@imgtec.com>
      Cc: Markos Chandras <markos.chandras@imgtec.com>
      Cc: stable <stable@vger.kernel.org> # v4.3
      Cc: linux-mips@linux-mips.org
      Cc: linux-kernel@vger.kernel.org
      Patchwork: https://patchwork.linux-mips.org/patch/12345/
      
      
      Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
      fa8ff601
    • Qais Yousef's avatar
      MIPS: Fix broken malta qemu · 19fb5818
      Qais Yousef authored
      
      
      Malta defconfig compiles with GIC on. Hence when compiling for SMP it causes
      the new IPI code to be activated. But on qemu malta there's no GIC causing a
      BUG_ON(!ipidomain) to be hit in mips_smp_ipi_init().
      
      Since in that configuration one can only run a single core SMP (!), skip IPI
      initialisation if we detect that this is the case. It is a sensible
      behaviour to introduce and should keep such possible configuration to run
      rather than die hard unnecessarily.
      
      Signed-off-by: default avatarQais Yousef <qsyousef@gmail.com>
      Reported-by: default avatarGuenter Roeck <linux@roeck-us.net>
      Tested-by: default avatarGuenter Roeck <linux@roeck-us.net>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: linux-mips@linux-mips.org
      Cc: linux-kernel@vger.kernel.org
      Patchwork: https://patchwork.linux-mips.org/patch/12892/
      
      
      Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
      19fb5818
  3. Mar 25, 2016
    • Alexander Potapenko's avatar
      mm, kasan: stackdepot implementation. Enable stackdepot for SLAB · cd11016e
      Alexander Potapenko authored
      
      
      Implement the stack depot and provide CONFIG_STACKDEPOT.  Stack depot
      will allow KASAN store allocation/deallocation stack traces for memory
      chunks.  The stack traces are stored in a hash table and referenced by
      handles which reside in the kasan_alloc_meta and kasan_free_meta
      structures in the allocated memory chunks.
      
      IRQ stack traces are cut below the IRQ entry point to avoid unnecessary
      duplication.
      
      Right now stackdepot support is only enabled in SLAB allocator.  Once
      KASAN features in SLAB are on par with those in SLUB we can switch SLUB
      to stackdepot as well, thus removing the dependency on SLUB stack
      bookkeeping, which wastes a lot of memory.
      
      This patch is based on the "mm: kasan: stack depots" patch originally
      prepared by Dmitry Chernenkov.
      
      Joonsoo has said that he plans to reuse the stackdepot code for the
      mm/page_owner.c debugging facility.
      
      [akpm@linux-foundation.org: s/depot_stack_handle/depot_stack_handle_t]
      [aryabinin@virtuozzo.com: comment style fixes]
      Signed-off-by: default avatarAlexander Potapenko <glider@google.com>
      Signed-off-by: default avatarAndrey Ryabinin <aryabinin@virtuozzo.com>
      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: Andrey Konovalov <adech.fo@gmail.com>
      Cc: Dmitry Vyukov <dvyukov@google.com>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      Cc: Konstantin Serebryany <kcc@google.com>
      Cc: Dmitry Chernenkov <dmitryc@google.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      cd11016e
    • Alexander Potapenko's avatar
      arch, ftrace: for KASAN put hard/soft IRQ entries into separate sections · be7635e7
      Alexander Potapenko authored
      
      
      KASAN needs to know whether the allocation happens in an IRQ handler.
      This lets us strip everything below the IRQ entry point to reduce the
      number of unique stack traces needed to be stored.
      
      Move the definition of __irq_entry to <linux/interrupt.h> so that the
      users don't need to pull in <linux/ftrace.h>.  Also introduce the
      __softirq_entry macro which is similar to __irq_entry, but puts the
      corresponding functions to the .softirqentry.text section.
      
      Signed-off-by: default avatarAlexander Potapenko <glider@google.com>
      Acked-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      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: Andrey Konovalov <adech.fo@gmail.com>
      Cc: Dmitry Vyukov <dvyukov@google.com>
      Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
      Cc: Konstantin Serebryany <kcc@google.com>
      Cc: Dmitry Chernenkov <dmitryc@google.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      be7635e7
    • Tony Luck's avatar
      [IA64] Enable preadv2 and pwritev2 syscalls for ia64 · 2d5ae5c2
      Tony Luck authored
      
      
      New system calls added in:
            f17d8b35
            vfs: vfs: Define new syscalls preadv2,pwritev2
      
      Signed-off-by: default avatarTony Luck <tony.luck@intel.com>
      2d5ae5c2
  4. Mar 24, 2016
    • Yoshinori Sato's avatar
      h8300: switch EARLYCON · 8cad4892
      Yoshinori Sato authored
      
      
      earlyprintk is architecture specific option.
      earlycon is generic and small footprint.
      
      Signed-off-by: default avatarYoshinori Sato <ysato@users.sourceforge.jp>
      8cad4892
    • Geert Uytterhoeven's avatar
      h8300: dts: Rename the serial port clock to fck · d8581616
      Geert Uytterhoeven authored
      
      
      The clock is really the device functional clock, not the interface
      clock. Rename it.
      
      Signed-off-by: default avatarGeert Uytterhoeven <geert+renesas@glider.be>
      Acked-by: default avatarLaurent Pinchart <laurent.pinchart@ideasonboard.com>
      d8581616
    • Mark Rutland's avatar
      arm64: mm: allow preemption in copy_to_user_page · 691b1e2e
      Mark Rutland authored
      
      
      Currently we disable preemption in copy_to_user_page; a behaviour that
      we inherited from the 32-bit arm code. This was necessary for older
      cores without broadcast data cache maintenance, and ensured that cache
      lines were dirtied and cleaned by the same CPU. On these systems dirty
      cache line migration was not possible, so this was sufficient to
      guarantee coherency.
      
      On contemporary systems, cache coherence protocols permit (dirty) cache
      lines to migrate between CPUs as a result of speculation, prefetching,
      and other behaviours. To account for this, in ARMv8 data cache
      maintenance operations are broadcast and affect all data caches in the
      domain associated with the VA (i.e. ISH for kernel and user mappings).
      
      In __switch_to we ensure that tasks can be safely migrated in the middle
      of a maintenance sequence, using a dsb(ish) to ensure prior explicit
      memory accesses are observed and cache maintenance operations are
      completed before a task can be run on another CPU.
      
      Given the above, it is not necessary to disable preemption in
      copy_to_user_page. This patch removes the preempt_{disable,enable}
      calls, permitting preemption.
      
      Signed-off-by: default avatarMark Rutland <mark.rutland@arm.com>
      Cc: Will Deacon <will.deacon@arm.com>
      Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
      691b1e2e
    • Mark Rutland's avatar
      arm64: consistently use p?d_set_huge · c661cb1c
      Mark Rutland authored
      
      
      Commit 324420bf ("arm64: add support for ioremap() block
      mappings") added new p?d_set_huge functions which do the hard work to
      generate and set a correct block entry.
      
      These differ from open-coded huge page creation in the early page table
      code by explicitly setting the P?D_TYPE_SECT bits (which are implicitly
      retained by mk_sect_prot() for any valid prot), but are otherwise
      identical (and cannot fail on arm64).
      
      For simplicity and consistency, make use of these in the initial page
      table creation code.
      
      Signed-off-by: default avatarMark Rutland <mark.rutland@arm.com>
      Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
      Cc: Will Deacon <will.deacon@arm.com>
      Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
      c661cb1c
    • Ard Biesheuvel's avatar
      arm64: kaslr: use callee saved register to preserve SCTLR across C call · d5e57437
      Ard Biesheuvel authored
      
      
      The KASLR code incorrectly expects the contents of x18 to be preserved
      across a call into C code, and uses it to stash the contents of SCTLR_EL1
      before enabling the MMU. If the MMU needs to be disabled again to create
      the randomized kernel mapping, x18 is written back to SCTLR_EL1, which is
      likely to crash the system if x18 has been clobbered by kasan_early_init()
      or kaslr_early_init(). So use x22 instead, which is not in use so far in
      head.S
      
      Signed-off-by: default avatarArd Biesheuvel <ard.biesheuvel@linaro.org>
      Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
      d5e57437
  5. Mar 23, 2016
  6. Mar 22, 2016
    • Ard Biesheuvel's avatar
      ia64/extable: use generic search and sort routines · 8fe9752e
      Ard Biesheuvel authored
      
      
      Replace the arch specific versions of search_extable() and
      sort_extable() with calls to the generic ones, which now support
      relative exception tables as well.
      
      Signed-off-by: default avatarArd Biesheuvel <ard.biesheuvel@linaro.org>
      Acked-by: default avatarTony Luck <tony.luck@intel.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      8fe9752e
    • Ard Biesheuvel's avatar
      x86/extable: use generic search and sort routines · 29934b0f
      Ard Biesheuvel authored
      
      
      Replace the arch specific versions of search_extable() and
      sort_extable() with calls to the generic ones, which now support
      relative exception tables as well.
      
      Signed-off-by: default avatarArd Biesheuvel <ard.biesheuvel@linaro.org>
      Acked-by: default avatarH. Peter Anvin <hpa@linux.intel.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      29934b0f
    • Ard Biesheuvel's avatar
      s390/extable: use generic search and sort routines · c352e8b6
      Ard Biesheuvel authored
      
      
      Replace the arch specific versions of search_extable() and
      sort_extable() with calls to the generic ones, which now support
      relative exception tables as well.
      
      Signed-off-by: default avatarArd Biesheuvel <ard.biesheuvel@linaro.org>
      Acked-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      c352e8b6
    • Ard Biesheuvel's avatar
      alpha/extable: use generic search and sort routines · e77986b5
      Ard Biesheuvel authored
      
      
      Replace the arch specific versions of search_extable() and
      sort_extable() with calls to the generic ones, which now support
      relative exception tables as well.
      
      Signed-off-by: default avatarArd Biesheuvel <ard.biesheuvel@linaro.org>
      Acked-by: default avatarRichard Henderson <rth@twiddle.net>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      e77986b5
    • Dmitry Vyukov's avatar
      kernel: add kcov code coverage · 5c9a8750
      Dmitry Vyukov authored
      kcov provides code coverage collection for coverage-guided fuzzing
      (randomized testing).  Coverage-guided fuzzing is a testing technique
      that uses coverage feedback to determine new interesting inputs to a
      system.  A notable user-space example is AFL
      (http://lcamtuf.coredump.cx/afl/).  However, this technique is not
      widely used for kernel testing due to missing compiler and kernel
      support.
      
      kcov does not aim to collect as much coverage as possible.  It aims to
      collect more or less stable coverage that is function of syscall inputs.
      To achieve this goal it does not collect coverage in soft/hard
      interrupts and instrumentation of some inherently non-deterministic or
      non-interesting parts of kernel is disbled (e.g.  scheduler, locking).
      
      Currently there is a single coverage collection mode (tracing), but the
      API anticipates additional collection modes.  Initially I also
      implemented a second mode which exposes coverage in a fixed-size hash
      table of counters (what Quentin used in his original patch).  I've
      dropped the second mode for simplicity.
      
      This patch adds the necessary support on kernel side.  The complimentary
      compiler support was added in gcc revision 231296.
      
      We've used this support to build syzkaller system call fuzzer, which has
      found 90 kernel bugs in just 2 months:
      
        https://github.com/google/syzkaller/wiki/Found-Bugs
      
      
      
      We've also found 30+ bugs in our internal systems with syzkaller.
      Another (yet unexplored) direction where kcov coverage would greatly
      help is more traditional "blob mutation".  For example, mounting a
      random blob as a filesystem, or receiving a random blob over wire.
      
      Why not gcov.  Typical fuzzing loop looks as follows: (1) reset
      coverage, (2) execute a bit of code, (3) collect coverage, repeat.  A
      typical coverage can be just a dozen of basic blocks (e.g.  an invalid
      input).  In such context gcov becomes prohibitively expensive as
      reset/collect coverage steps depend on total number of basic
      blocks/edges in program (in case of kernel it is about 2M).  Cost of
      kcov depends only on number of executed basic blocks/edges.  On top of
      that, kernel requires per-thread coverage because there are always
      background threads and unrelated processes that also produce coverage.
      With inlined gcov instrumentation per-thread coverage is not possible.
      
      kcov exposes kernel PCs and control flow to user-space which is
      insecure.  But debugfs should not be mapped as user accessible.
      
      Based on a patch by Quentin Casasnovas.
      
      [akpm@linux-foundation.org: make task_struct.kcov_mode have type `enum kcov_mode']
      [akpm@linux-foundation.org: unbreak allmodconfig]
      [akpm@linux-foundation.org: follow x86 Makefile layout standards]
      Signed-off-by: default avatarDmitry Vyukov <dvyukov@google.com>
      Reviewed-by: default avatarKees Cook <keescook@chromium.org>
      Cc: syzkaller <syzkaller@googlegroups.com>
      Cc: Vegard Nossum <vegard.nossum@oracle.com>
      Cc: Catalin Marinas <catalin.marinas@arm.com>
      Cc: Tavis Ormandy <taviso@google.com>
      Cc: Will Deacon <will.deacon@arm.com>
      Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com>
      Cc: Kostya Serebryany <kcc@google.com>
      Cc: Eric Dumazet <edumazet@google.com>
      Cc: Alexander Potapenko <glider@google.com>
      Cc: Kees Cook <keescook@google.com>
      Cc: Bjorn Helgaas <bhelgaas@google.com>
      Cc: Sasha Levin <sasha.levin@oracle.com>
      Cc: David Drysdale <drysdale@google.com>
      Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
      Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
      Cc: Kirill A. Shutemov <kirill@shutemov.name>
      Cc: Jiri Slaby <jslaby@suse.cz>
      Cc: Ingo Molnar <mingo@elte.hu>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: "H. Peter Anvin" <hpa@zytor.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      5c9a8750
    • Alexandre Bounine's avatar
      rapidio: add global inbound port write interfaces · 9a0b0627
      Alexandre Bounine authored
      
      
      Add new Port Write handler registration interfaces that attach PW
      handlers to local mport device objects.  This is different from old
      interface that attaches PW callback to individual RapidIO device.  The
      new interfaces are intended for use for common event handling (e.g.
      hot-plug notifications) while the old interface is available for
      individual device drivers.
      
      This patch is based on patch proposed by Andre van Herk but preserves
      existing per-device interface and adds lock protection for list
      handling.
      
      Signed-off-by: default avatarAlexandre Bounine <alexandre.bounine@idt.com>
      Cc: Matt Porter <mporter@kernel.crashing.org>
      Cc: Aurelien Jacquiot <a-jacquiot@ti.com>
      Cc: Andre van Herk <andre.van.herk@prodrive-technologies.com>
      Cc: Stephen Rothwell <sfr@canb.auug.org.au>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      9a0b0627
    • Alexandre Bounine's avatar
      powerpc/fsl_rio: changes to mport registration · dd64f4fe
      Alexandre Bounine authored
      
      
      Change mport object initialization/registration sequence to match
      reworked version of rio_register_mport() in the core code.
      
      Signed-off-by: default avatarAlexandre Bounine <alexandre.bounine@idt.com>
      Cc: Matt Porter <mporter@kernel.crashing.org>
      Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
      Cc: Aurelien Jacquiot <a-jacquiot@ti.com>
      Cc: Andre van Herk <andre.van.herk@prodrive-technologies.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      dd64f4fe
    • Jann Horn's avatar
      fs/coredump: prevent fsuid=0 dumps into user-controlled directories · 378c6520
      Jann Horn authored
      
      
      This commit fixes the following security hole affecting systems where
      all of the following conditions are fulfilled:
      
       - The fs.suid_dumpable sysctl is set to 2.
       - The kernel.core_pattern sysctl's value starts with "/". (Systems
         where kernel.core_pattern starts with "|/" are not affected.)
       - Unprivileged user namespace creation is permitted. (This is
         true on Linux >=3.8, but some distributions disallow it by
         default using a distro patch.)
      
      Under these conditions, if a program executes under secure exec rules,
      causing it to run with the SUID_DUMP_ROOT flag, then unshares its user
      namespace, changes its root directory and crashes, the coredump will be
      written using fsuid=0 and a path derived from kernel.core_pattern - but
      this path is interpreted relative to the root directory of the process,
      allowing the attacker to control where a coredump will be written with
      root privileges.
      
      To fix the security issue, always interpret core_pattern for dumps that
      are written under SUID_DUMP_ROOT relative to the root directory of init.
      
      Signed-off-by: default avatarJann Horn <jann@thejh.net>
      Acked-by: default avatarKees Cook <keescook@chromium.org>
      Cc: Al Viro <viro@zeniv.linux.org.uk>
      Cc: "Eric W. Biederman" <ebiederm@xmission.com>
      Cc: Andy Lutomirski <luto@kernel.org>
      Cc: Oleg Nesterov <oleg@redhat.com>
      Cc: <stable@vger.kernel.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      378c6520
    • Andy Lutomirski's avatar
      x86/compat: remove is_compat_task() · f970165b
      Andy Lutomirski authored
      
      
      x86's is_compat_task always checked the current syscall type, not the
      task type.  It has no non-arch users any more, so just remove it to
      avoid confusion.
      
      On x86, nothing should really be checking the task ABI.  There are
      legitimate users for the syscall ABI and for the mm ABI.
      
      Signed-off-by: default avatarAndy Lutomirski <luto@kernel.org>
      Cc: Ingo Molnar <mingo@elte.hu>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: "H. Peter Anvin" <hpa@zytor.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      f970165b
    • Andy Lutomirski's avatar
      sparc/syscall: fix syscall_get_arch · 203f7907
      Andy Lutomirski authored
      
      
      Sparc's syscall_get_arch was buggy: it returned the task arch, not the
      syscall arch.  This could confuse seccomp and audit.
      
      I don't think this is as bad for seccomp as it looks: sparc's 32-bit and
      64-bit syscalls are numbered the same.
      
      Signed-off-by: default avatarAndy Lutomirski <luto@kernel.org>
      Cc: David S. Miller <davem@davemloft.net>
      Cc: Sam Ravnborg <sam@ravnborg.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      203f7907
    • Andy Lutomirski's avatar
      sparc/compat: provide an accurate in_compat_syscall implementation · 069923d8
      Andy Lutomirski authored
      
      
      On sparc64 compat-enabled kernels, any task can make 32-bit and 64-bit
      syscalls.  is_compat_task returns true in 32-bit tasks, which does not
      necessarily imply that the current syscall is 32-bit.
      
      Provide an in_compat_syscall implementation that checks whether the
      current syscall is compat.
      
      As far as I know, sparc is the only architecture on which is_compat_task
      checks the compat status of the task and on which the compat status of a
      syscall can differ from the compat status of the task.  On x86,
      is_compat_task checks the syscall type, not the task type.
      
      [akpm@linux-foundation.org: add comment, per Sam]
      [akpm@linux-foundation.org: update comment, per Andy]
      Signed-off-by: default avatarAndy Lutomirski <luto@kernel.org>
      Acked-by: default avatarDavid S. Miller <davem@davemloft.net>
      Cc: Sam Ravnborg <sam@ravnborg.org>
      Cc: Andy Lutomirski <luto@kernel.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      069923d8
    • Paolo Bonzini's avatar
      KVM: page_track: fix access to NULL slot · a6adb106
      Paolo Bonzini authored
      
      
      This happens when doing the reboot test from virt-tests:
      
      [  131.833653] BUG: unable to handle kernel NULL pointer dereference at           (null)
      [  131.842461] IP: [<ffffffffa0950087>] kvm_page_track_is_active+0x17/0x60 [kvm]
      [  131.850500] PGD 0
      [  131.852763] Oops: 0000 [#1] SMP
      [  132.007188] task: ffff880075fbc500 ti: ffff880850a3c000 task.ti: ffff880850a3c000
      [  132.138891] Call Trace:
      [  132.141639]  [<ffffffffa092bd11>] page_fault_handle_page_track+0x31/0x40 [kvm]
      [  132.149732]  [<ffffffffa093380f>] paging64_page_fault+0xff/0x910 [kvm]
      [  132.172159]  [<ffffffffa092c734>] kvm_mmu_page_fault+0x64/0x110 [kvm]
      [  132.179372]  [<ffffffffa06743c2>] handle_exception+0x1b2/0x430 [kvm_intel]
      [  132.187072]  [<ffffffffa067a301>] vmx_handle_exit+0x1e1/0xc50 [kvm_intel]
      ...
      
      Cc: Xiao Guangrong <guangrong.xiao@linux.intel.com>
      Fixes: 3d0c27ad
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      a6adb106
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