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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: "Eric W. Biederman" <ebiederm@xmission.com>
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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: 948a34cf3988 ("[MIPS] Maintain si_code field properly for FP exceptions")
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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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 was introduced in 2.3.41 so this mess has had a long time for
people to be able to start depending on it.
As this bug has existed for 17 years already I don't know if it is
worth fixing. It is definitely worth documenting what is going
on so that no one decides to copy this bad decision.
Cc: "David S. Miller" <davem@davemloft.net>
Cc: sparclinux@vger.kernel.org
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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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 ia64 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 in 2.3.51 so this mess has had a long time for
people to be able to start depending on it.
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: linux-ia64@vger.kernel.org
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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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: Richard 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: "Eric W. Biederman" <ebiederm@xmission.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull ->s_options removal from Al Viro:
"Preparations for fsmount/fsopen stuff (coming next cycle). Everything
gets moved to explicit ->show_options(), killing ->s_options off +
some cosmetic bits around fs/namespace.c and friends. Basically, the
stuff needed to work with fsmount series with minimum of conflicts
with other work.
It's not strictly required for this merge window, but it would reduce
the PITA during the coming cycle, so it would be nice to have those
bits and pieces out of the way"
* 'work.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
isofs: Fix isofs_show_options()
VFS: Kill off s_options and helpers
orangefs: Implement show_options
9p: Implement show_options
isofs: Implement show_options
afs: Implement show_options
affs: Implement show_options
befs: Implement show_options
spufs: Implement show_options
bpf: Implement show_options
ramfs: Implement show_options
pstore: Implement show_options
omfs: Implement show_options
hugetlbfs: Implement show_options
VFS: Don't use save/replace_mount_options if not using generic_show_options
VFS: Provide empty name qstr
VFS: Make get_filesystem() return the affected filesystem
VFS: Clean up whitespace in fs/namespace.c and fs/super.c
Provide a function to create a NUL-terminated string from unterminated data
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git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull uacess-unaligned removal from Al Viro:
"That stuff had just one user, and an exotic one, at that - binfmt_flat
on arm and m68k"
* 'work.uaccess-unaligned' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
kill {__,}{get,put}_user_unaligned()
binfmt_flat: flat_{get,put}_addr_from_rp() should be able to fail
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Pull MIPS updates from Ralf Baechle:
"Boston platform support:
- Document DT bindings
- Add CLK driver for board clocks
CM:
- Avoid per-core locking with CM3 & higher
- WARN on attempt to lock invalid VP, not BUG
CPS:
- Select CONFIG_SYS_SUPPORTS_SCHED_SMT for MIPSr6
- Prevent multi-core with dcache aliasing
- Handle cores not powering down more gracefully
- Handle spurious VP starts more gracefully
DSP:
- Add lwx & lhx missaligned access support
eBPF:
- Add MIPS support along with many supporting change to add the
required infrastructure
Generic arch code:
- Misc sysmips MIPS_ATOMIC_SET fixes
- Drop duplicate HAVE_SYSCALL_TRACEPOINTS
- Negate error syscall return in trace
- Correct forced syscall errors
- Traced negative syscalls should return -ENOSYS
- Allow samples/bpf/tracex5 to access syscall arguments for sane
traces
- Cleanup from old Kconfig options in defconfigs
- Fix PREF instruction usage by memcpy for MIPS R6
- Fix various special cases in the FPU eulation
- Fix some special cases in MIPS16e2 support
- Fix MIPS I ISA /proc/cpuinfo reporting
- Sort MIPS Kconfig alphabetically
- Fix minimum alignment requirement of IRQ stack as required by
ABI / GCC
- Fix special cases in the module loader
- Perform post-DMA cache flushes on systems with MAARs
- Probe the I6500 CPU
- Cleanup cmpxchg and add support for 1 and 2 byte operations
- Use queued read/write locks (qrwlock)
- Use queued spinlocks (qspinlock)
- Add CPU shared FTLB feature detection
- Handle tlbex-tlbp race condition
- Allow storing pgd in C0_CONTEXT for MIPSr6
- Use current_cpu_type() in m4kc_tlbp_war()
- Support Boston in the generic kernel
Generic platform:
- yamon-dt: Pull YAMON DT shim code out of SEAD-3 board
- yamon-dt: Support > 256MB of RAM
- yamon-dt: Use serial* rather than uart* aliases
- Abstract FDT fixup application
- Set RTC_ALWAYS_BCD to 0
- Add a MAINTAINERS entry
core kernel:
- qspinlock.c: include linux/prefetch.h
Loongson 3:
- Add support
Perf:
- Add I6500 support
SEAD-3:
- Remove GIC timer from DT
- Set interrupt-parent per-device, not at root node
- Fix GIC interrupt specifiers
SMP:
- Skip IPI setup if we only have a single CPU
VDSO:
- Make comment match reality
- Improvements to time code in VDSO"
* 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus: (86 commits)
locking/qspinlock: Include linux/prefetch.h
MIPS: Fix MIPS I ISA /proc/cpuinfo reporting
MIPS: Fix minimum alignment requirement of IRQ stack
MIPS: generic: Support MIPS Boston development boards
MIPS: DTS: img: Don't attempt to build-in all .dtb files
clk: boston: Add a driver for MIPS Boston board clocks
dt-bindings: Document img,boston-clock binding
MIPS: Traced negative syscalls should return -ENOSYS
MIPS: Correct forced syscall errors
MIPS: Negate error syscall return in trace
MIPS: Drop duplicate HAVE_SYSCALL_TRACEPOINTS select
MIPS16e2: Provide feature overrides for non-MIPS16 systems
MIPS: MIPS16e2: Report ASE presence in /proc/cpuinfo
MIPS: MIPS16e2: Subdecode extended LWSP/SWSP instructions
MIPS: MIPS16e2: Identify ASE presence
MIPS: VDSO: Fix a mismatch between comment and preprocessor constant
MIPS: VDSO: Add implementation of gettimeofday() fallback
MIPS: VDSO: Add implementation of clock_gettime() fallback
MIPS: VDSO: Fix conversions in do_monotonic()/do_monotonic_coarse()
MIPS: Use current_cpu_type() in m4kc_tlbp_war()
...
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git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml
Pull UML updates from Richard Weinberger:
"Mostly fixes for UML:
- First round of fixes for PTRACE_GETRESET/SETREGSET
- A printf vs printk cleanup
- Minor improvements"
* 'for-linus-4.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml:
um: Correctly check for PTRACE_GETRESET/SETREGSET
um: v2: Use generic NOTES macro
um: Add kerneldoc for userspace_tramp() and start_userspace()
um: Add kerneldoc for segv_handler
um: stub-data.h: remove superfluous include
um: userspace - be more verbose in ptrace set regs error
um: add dummy ioremap and iounmap functions
um: Allow building and running on older hosts
um: Avoid longjmp/setjmp symbol clashes with libpthread.a
um: console: Ignore console= option
um: Use os_warn to print out pre-boot warning/error messages
um: Add os_warn() for pre-boot warning/error messages
um: Use os_info for the messages on normal path
um: Add os_info() for pre-boot information messages
um: Use printk instead of printf in make_uml_dir
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Pull more KVM updates from Radim Krčmář:
"Second batch of KVM updates for v4.13
Common:
- add uevents for VM creation/destruction
- annotate and properly access RCU-protected objects
s390:
- rename IOCTL added in the first v4.13 merge
x86:
- emulate VMLOAD VMSAVE feature in SVM
- support paravirtual asynchronous page fault while nested
- add Hyper-V userspace interfaces for better migration
- improve master clock corner cases
- extend internal error reporting after EPT misconfig
- correct single-stepping of emulated instructions in SVM
- handle MCE during VM entry
- fix nVMX VM entry checks and nVMX VMCS shadowing"
* tag 'kvm-4.13-2' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (28 commits)
kvm: x86: hyperv: make VP_INDEX managed by userspace
KVM: async_pf: Let guest support delivery of async_pf from guest mode
KVM: async_pf: Force a nested vmexit if the injected #PF is async_pf
KVM: async_pf: Add L1 guest async_pf #PF vmexit handler
KVM: x86: Simplify kvm_x86_ops->queue_exception parameter list
kvm: x86: hyperv: add KVM_CAP_HYPERV_SYNIC2
KVM: x86: make backwards_tsc_observed a per-VM variable
KVM: trigger uevents when creating or destroying a VM
KVM: SVM: Enable Virtual VMLOAD VMSAVE feature
KVM: SVM: Add Virtual VMLOAD VMSAVE feature definition
KVM: SVM: Rename lbr_ctl field in the vmcb control area
KVM: SVM: Prepare for new bit definition in lbr_ctl
KVM: SVM: handle singlestep exception when skipping emulated instructions
KVM: x86: take slots_lock in kvm_free_pit
KVM: s390: Fix KVM_S390_GET_CMMA_BITS ioctl definition
kvm: vmx: Properly handle machine check during VM-entry
KVM: x86: update master clock before computing kvmclock_offset
kvm: nVMX: Shadow "high" parts of shadowed 64-bit VMCS fields
kvm: nVMX: Fix nested_vmx_check_msr_bitmap_controls
kvm: nVMX: Validate the I/O bitmaps on nested VM-entry
...
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git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6
Pull crypto fixes from Herbert Xu:
- fix new compiler warnings in cavium
- set post-op IV properly in caam (this fixes chaining)
- fix potential use-after-free in atmel in case of EBUSY
- fix sleeping in softirq path in chcr
- disable buggy sha1-avx2 driver (may overread and page fault)
- fix use-after-free on signals in caam
* 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6:
crypto: cavium - make several functions static
crypto: chcr - Avoid algo allocation in softirq.
crypto: caam - properly set IV after {en,de}crypt
crypto: atmel - only treat EBUSY as transient if backlog
crypto: af_alg - Avoid sock_graft call warning
crypto: caam - fix signals handling
crypto: sha1-ssse3 - Disable avx2
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Merge even more updates from Andrew Morton:
- a few leftovers
- fault-injector rework
- add a module loader test driver
* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
kmod: throttle kmod thread limit
kmod: add test driver to stress test the module loader
MAINTAINERS: give kmod some maintainer love
xtensa: use generic fb.h
fault-inject: add /proc/<pid>/fail-nth
fault-inject: simplify access check for fail-nth
fault-inject: make fail-nth read/write interface symmetric
fault-inject: parse as natural 1-based value for fail-nth write interface
fault-inject: automatically detect the number base for fail-nth write interface
kernel/watchdog.c: use better pr_fmt prefix
MAINTAINERS: move the befs tree to kernel.org
lib/atomic64_test.c: add a test that atomic64_inc_not_zero() returns an int
mm: fix overflow check in expand_upwards()
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Pull arch/tile updates from Chris Metcalf:
"This adds support for an <arch/intreg.h> to help with removing
__need_xxx #defines from glibc, and removes some dead code in
arch/tile/mm/init.c"
* git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile:
mm, tile: drop arch_{add,remove}_memory
tile: prefer <arch/intreg.h> to __need_int_reg_t
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git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux
Pull powerpc fixes from Michael Ellerman:
"Nothing that really stands out, just a bunch of fixes that have come
in in the last couple of weeks.
None of these are actually fixes for code that is new in 4.13. It's
roughly half older bugs, with fixes going to stable, and half
fixes/updates for Power9.
Thanks to: Aneesh Kumar K.V, Anton Blanchard, Balbir Singh, Benjamin
Herrenschmidt, Madhavan Srinivasan, Michael Neuling, Nicholas Piggin,
Oliver O'Halloran"
* tag 'powerpc-4.13-2' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
powerpc/64: Fix atomic64_inc_not_zero() to return an int
powerpc: Fix emulation of mfocrf in emulate_step()
powerpc: Fix emulation of mcrf in emulate_step()
powerpc/perf: Add POWER9 alternate PM_RUN_CYC and PM_RUN_INST_CMPL events
powerpc/perf: Fix SDAR_MODE value for continous sampling on Power9
powerpc/asm: Mark cr0 as clobbered in mftb()
powerpc/powernv: Fix local TLB flush for boot and MCE on POWER9
powerpc/mm/radix: Synchronize updates to the process table
powerpc/mm/radix: Properly clear process table entry
powerpc/powernv: Tell OPAL about our MMU mode on POWER9
powerpc/kexec: Fix radix to hash kexec due to IAMR/AMOR
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The arch uses a verbatim copy of the asm-generic version and does not
add any own implementations to the header, so use asm-generic/fb.h
instead of duplicating code.
Link: http://lkml.kernel.org/r/20170517083545.2115-1-tklauser@distanz.ch
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Acked-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci
Pull PCI fixes from Bjorn Helgaas:
- fix a typo that broke Rockchip enumeration
- fix a new memory leak in the ARM host bridge failure path
* tag 'pci-v4.13-fixes-1' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci:
PCI: rockchip: Check for pci_scan_root_bus_bridge() failure correctly
ARM/PCI: Fix pcibios_init_resource() struct pci_host_bridge leak
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Hyper-V identifies vCPUs by Virtual Processor Index, which can be
queried via HV_X64_MSR_VP_INDEX msr. It is defined by the spec as a
sequential number which can't exceed the maximum number of vCPUs per VM.
APIC ids can be sparse and thus aren't a valid replacement for VP
indices.
Current KVM uses its internal vcpu index as VP_INDEX. However, to make
it predictable and persistent across VM migrations, the userspace has to
control the value of VP_INDEX.
This patch achieves that, by storing vp_index explicitly on vcpu, and
allowing HV_X64_MSR_VP_INDEX to be set from the host side. For
compatibility it's initialized to KVM vcpu index. Also a few variables
are renamed to make clear distinction betweed this Hyper-V vp_index and
KVM vcpu_id (== APIC id). Besides, a new capability,
KVM_CAP_HYPERV_VP_INDEX, is added to allow the userspace to skip
attempting msr writes where unsupported, to avoid spamming error logs.
Signed-off-by: Roman Kagan <rkagan@virtuozzo.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
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Adds another flag bit (bit 2) to MSR_KVM_ASYNC_PF_EN. If bit 2 is 1,
async page faults are delivered to L1 as #PF vmexits; if bit 2 is 0,
kvm_can_do_async_pf returns 0 if in guest mode.
This is similar to what svm.c wanted to do all along, but it is only
enabled for Linux as L1 hypervisor. Foreign hypervisors must never
receive async page faults as vmexits, because they'd probably be very
confused about that.
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
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Add an nested_apf field to vcpu->arch.exception to identify an async page
fault, and constructs the expected vm-exit information fields. Force a
nested VM exit from nested_vmx_check_exception() if the injected #PF is
async page fault.
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
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This patch adds the L1 guest async page fault #PF vmexit handler, such
by L1 similar to ordinary async page fault.
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
[Passed insn parameters to kvm_mmu_page_fault().]
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
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This patch removes all arguments except the first in
kvm_x86_ops->queue_exception since they can extract the arguments from
vcpu->arch.exception themselves.
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild
Pull more Kbuild updates from Masahiro Yamada:
- Move generic-y of exported headers to uapi/asm/Kbuild for complete
de-coupling of UAPI
- Clean up scripts/Makefile.headersinst
- Fix host programs for 32 bit machine with XFS file system
* tag 'kbuild-v4.13-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (29 commits)
kbuild: Enable Large File Support for hostprogs
kbuild: remove wrapper files handling from Makefile.headersinst
kbuild: split exported generic header creation into uapi-asm-generic
kbuild: do not include old-kbuild-file from Makefile.headersinst
xtensa: move generic-y of exported headers to uapi/asm/Kbuild
unicore32: move generic-y of exported headers to uapi/asm/Kbuild
tile: move generic-y of exported headers to uapi/asm/Kbuild
sparc: move generic-y of exported headers to uapi/asm/Kbuild
sh: move generic-y of exported headers to uapi/asm/Kbuild
parisc: move generic-y of exported headers to uapi/asm/Kbuild
openrisc: move generic-y of exported headers to uapi/asm/Kbuild
nios2: move generic-y of exported headers to uapi/asm/Kbuild
nios2: remove unneeded arch/nios2/include/(generated/)asm/signal.h
microblaze: move generic-y of exported headers to uapi/asm/Kbuild
metag: move generic-y of exported headers to uapi/asm/Kbuild
m68k: move generic-y of exported headers to uapi/asm/Kbuild
m32r: move generic-y of exported headers to uapi/asm/Kbuild
ia64: remove redundant generic-y += kvm_para.h from asm/Kbuild
hexagon: move generic-y of exported headers to uapi/asm/Kbuild
h8300: move generic-y of exported headers to uapi/asm/Kbuild
...
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There is a flaw in the Hyper-V SynIC implementation in KVM: when message
page or event flags page is enabled by setting the corresponding msr,
KVM zeroes it out. This is problematic because on migration the
corresponding MSRs are loaded on the destination, so the content of
those pages is lost.
This went unnoticed so far because the only user of those pages was
in-KVM hyperv synic timers, which could continue working despite that
zeroing.
Newer QEMU uses those pages for Hyper-V VMBus implementation, and
zeroing them breaks the migration.
Besides, in newer QEMU the content of those pages is fully managed by
QEMU, so zeroing them is undesirable even when writing the MSRs from the
guest side.
To support this new scheme, introduce a new capability,
KVM_CAP_HYPERV_SYNIC2, which, when enabled, makes sure that the synic
pages aren't zeroed out in KVM.
Signed-off-by: Roman Kagan <rkagan@virtuozzo.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
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The backwards_tsc_observed global introduced in commit 16a9602 is never
reset to false. If a VM happens to be running while the host is suspended
(a common source of the TSC jumping backwards), master clock will never
be enabled again for any VM. In contrast, if no VM is running while the
host is suspended, master clock is unaffected. This is inconsistent and
unnecessarily strict. Let's track the backwards_tsc_observed variable
separately and let each VM start with a clean slate.
Real world impact: My Windows VMs get slower after my laptop undergoes a
suspend/resume cycle. The only way to get the perf back is unloading and
reloading the kvm module.
Signed-off-by: Ladi Prosek <lprosek@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
|
|
Make the code like the rest of the kernel.
Link: http://lkml.kernel.org/r/1cd3d401626e51ea0e2333a860e76e80bc560a4c.1499284835.git.joe@perches.com
Signed-off-by: Joe Perches <joe@perches.com>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Make the code like the rest of the kernel.
Link: http://lkml.kernel.org/r/f81bb2a67a97b1fd8b6ea99bd350d8a0f6864fb1.1499284835.git.joe@perches.com
Signed-off-by: Joe Perches <joe@perches.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Rich Felker <dalias@libc.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Make the code like the rest of the kernel.
Link: http://lkml.kernel.org/r/756d3fb543e981b9284e756fa27616725a354b28.1499284835.git.joe@perches.com
Signed-off-by: Joe Perches <joe@perches.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Make the code like the rest of the kernel.
Link: http://lkml.kernel.org/r/14db9c166d5b68efa77e337cfe49bb9b29bca3f7.1499284835.git.joe@perches.com
Signed-off-by: Joe Perches <joe@perches.com>
Acked-by: Greg Ungerer <gerg@linux-m68k.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Make the use of inline like the rest of the kernel.
Link: http://lkml.kernel.org/r/f42b2202bd0d4e7ccf79ce5348bb255a035e67bb.1499284835.git.joe@perches.com
Signed-off-by: Joe Perches <joe@perches.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Make the use of inline like the rest of the kernel.
Link: http://lkml.kernel.org/r/d47074493af80ce12590340294bc49618165c30d.1499284835.git.joe@perches.com
Signed-off-by: Joe Perches <joe@perches.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Make the use of asmlinkage like the rest of the kernel.
Link: http://lkml.kernel.org/r/efb2dfed4d9315bf68ec0334c81b65af176a0174.1499284835.git.joe@perches.com
Signed-off-by: Joe Perches <joe@perches.com>
Cc: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Move inline to be like the rest of the kernel.
Link: http://lkml.kernel.org/r/6bf1bec049897c4158f698b866810f47c728f233.1499284835.git.joe@perches.com
Signed-off-by: Joe Perches <joe@perches.com>
Cc: Mikael Starvik <starvik@axis.com>
Cc: Jesper Nilsson <jesper.nilsson@axis.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Convert 'u8 inline' to 'inline u8' to be the same style used by the rest
of the kernel.
Miscellanea:
jornada_ssp_reverse is an odd function.
It is declared inline but is also EXPORT_SYMBOL.
It is also apparently only used by jornada720_ssp.c
Likely the EXPORT_SYMBOL could be removed and the function
converted to static.
The addition of static and removal of EXPORT_SYMBOL was not done.
Link: http://lkml.kernel.org/r/5bd3b2bf39c6c9caf773949f18158f8f5ec08582.1499284835.git.joe@perches.com
Signed-off-by: Joe Perches <joe@perches.com>
Cc: Russell King <linux@armlinux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
asmlinkage is either 'extern "C"' or blank.
Move the uses of asmlinkage before the return types to be similar
to the rest of the kernel.
Link: http://lkml.kernel.org/r/005b8e120650c6a13b541e420f4e3605603fe9e6.1499284835.git.joe@perches.com
Signed-off-by: Joe Perches <joe@perches.com>
Cc: Christoffer Dall <christoffer.dall@linaro.org>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krcmar <rkrcmar@redhat.com>
Cc: Russell King <linux@armlinux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
semantic
__GFP_REPEAT was designed to allow retry-but-eventually-fail semantic to
the page allocator. This has been true but only for allocations
requests larger than PAGE_ALLOC_COSTLY_ORDER. It has been always
ignored for smaller sizes. This is a bit unfortunate because there is
no way to express the same semantic for those requests and they are
considered too important to fail so they might end up looping in the
page allocator for ever, similarly to GFP_NOFAIL requests.
Now that the whole tree has been cleaned up and accidental or misled
usage of __GFP_REPEAT flag has been removed for !costly requests we can
give the original flag a better name and more importantly a more useful
semantic. Let's rename it to __GFP_RETRY_MAYFAIL which tells the user
that the allocator would try really hard but there is no promise of a
success. This will work independent of the order and overrides the
default allocator behavior. Page allocator users have several levels of
guarantee vs. cost options (take GFP_KERNEL as an example)
- GFP_KERNEL & ~__GFP_RECLAIM - optimistic allocation without _any_
attempt to free memory at all. The most light weight mode which even
doesn't kick the background reclaim. Should be used carefully because
it might deplete the memory and the next user might hit the more
aggressive reclaim
- GFP_KERNEL & ~__GFP_DIRECT_RECLAIM (or GFP_NOWAIT)- optimistic
allocation without any attempt to free memory from the current
context but can wake kswapd to reclaim memory if the zone is below
the low watermark. Can be used from either atomic contexts or when
the request is a performance optimization and there is another
fallback for a slow path.
- (GFP_KERNEL|__GFP_HIGH) & ~__GFP_DIRECT_RECLAIM (aka GFP_ATOMIC) -
non sleeping allocation with an expensive fallback so it can access
some portion of memory reserves. Usually used from interrupt/bh
context with an expensive slow path fallback.
- GFP_KERNEL - both background and direct reclaim are allowed and the
_default_ page allocator behavior is used. That means that !costly
allocation requests are basically nofail but there is no guarantee of
that behavior so failures have to be checked properly by callers
(e.g. OOM killer victim is allowed to fail currently).
- GFP_KERNEL | __GFP_NORETRY - overrides the default allocator behavior
and all allocation requests fail early rather than cause disruptive
reclaim (one round of reclaim in this implementation). The OOM killer
is not invoked.
- GFP_KERNEL | __GFP_RETRY_MAYFAIL - overrides the default allocator
behavior and all allocation requests try really hard. The request
will fail if the reclaim cannot make any progress. The OOM killer
won't be triggered.
- GFP_KERNEL | __GFP_NOFAIL - overrides the default allocator behavior
and all allocation requests will loop endlessly until they succeed.
This might be really dangerous especially for larger orders.
Existing users of __GFP_REPEAT are changed to __GFP_RETRY_MAYFAIL
because they already had their semantic. No new users are added.
__alloc_pages_slowpath is changed to bail out for __GFP_RETRY_MAYFAIL if
there is no progress and we have already passed the OOM point.
This means that all the reclaim opportunities have been exhausted except
the most disruptive one (the OOM killer) and a user defined fallback
behavior is more sensible than keep retrying in the page allocator.
[akpm@linux-foundation.org: fix arch/sparc/kernel/mdesc.c]
[mhocko@suse.com: semantic fix]
Link: http://lkml.kernel.org/r/20170626123847.GM11534@dhcp22.suse.cz
[mhocko@kernel.org: address other thing spotted by Vlastimil]
Link: http://lkml.kernel.org/r/20170626124233.GN11534@dhcp22.suse.cz
Link: http://lkml.kernel.org/r/20170623085345.11304-3-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Alex Belits <alex.belits@cavium.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Darrick J. Wong <darrick.wong@oracle.com>
Cc: David Daney <david.daney@cavium.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: NeilBrown <neilb@suse.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Patch series "mm: give __GFP_REPEAT a better semantic".
The main motivation for the change is that the current implementation of
__GFP_REPEAT is not very much useful.
The documentation says:
* __GFP_REPEAT: Try hard to allocate the memory, but the allocation attempt
* _might_ fail. This depends upon the particular VM implementation.
It just fails to mention that this is true only for large (costly) high
order which has been the case since the flag was introduced. A similar
semantic would be really helpful for smal orders as well, though,
because we have places where a failure with a specific fallback error
handling is preferred to a potential endless loop inside the page
allocator.
The earlier cleanup dropped __GFP_REPEAT usage for low (!costly) order
users so only those which might use larger orders have stayed. One new
user added in the meantime is addressed in patch 1.
Let's rename the flag to something more verbose and use it for existing
users. Semantic for those will not change. Then implement low
(!costly) orders failure path which is hit after the page allocator is
about to invoke the oom killer. With that we have a good counterpart
for __GFP_NORETRY and finally can tell try as hard as possible without
the OOM killer.
Xfs code already has an existing annotation for allocations which are
allowed to fail and we can trivially map them to the new gfp flag
because it will provide the semantic KM_MAYFAIL wants. Christoph didn't
consider the new flag really necessary but didn't respond to the OOM
killer aspect of the change so I have kept the patch. If this is still
seen as not really needed I can drop the patch.
kvmalloc will allow also !costly high order allocations to retry hard
before falling back to the vmalloc.
drm/i915 asked for the new semantic explicitly.
Memory migration code, especially for the memory hotplug, should back
off rather than invoking the OOM killer as well.
This patch (of 6):
Commit 3377e227af44 ("MIPS: Add 48-bit VA space (and 4-level page
tables) for 4K pages.") has added a new __GFP_REPEAT user but using this
flag doesn't really make any sense for order-0 request which is the case
here because PUD_ORDER is 0. __GFP_REPEAT has historically effect only
on allocation requests with order > PAGE_ALLOC_COSTLY_ORDER.
This doesn't introduce any functional change. This is a preparatory
patch for later work which renames the flag and redefines its semantic.
Link: http://lkml.kernel.org/r/20170623085345.11304-2-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Alex Belits <alex.belits@cavium.com>
Cc: David Daney <david.daney@cavium.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: NeilBrown <neilb@suse.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
When RLIMIT_STACK is, for example, 256MB, the current code results in a
gap between the top of the task and mmap_base of 256MB, failing to take
into account the amount by which the stack address was randomized. In
other words, the stack gets less than RLIMIT_STACK space.
Ensure that the gap between the stack and mmap_base always takes stack
randomization and the stack guard gap into account.
Inspired by Daniel Micay's linux-hardened tree.
Link: http://lkml.kernel.org/r/20170622200033.25714-4-riel@redhat.com
Signed-off-by: Rik van Riel <riel@redhat.com>
Reported-by: Florian Weimer <fweimer@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Daniel Micay <danielmicay@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
When RLIMIT_STACK is, for example, 256MB, the current code results in a
gap between the top of the task and mmap_base of 256MB, failing to take
into account the amount by which the stack address was randomized. In
other words, the stack gets less than RLIMIT_STACK space.
Ensure that the gap between the stack and mmap_base always takes stack
randomization and the stack guard gap into account.
Obtained from Daniel Micay's linux-hardened tree.
Link: http://lkml.kernel.org/r/20170622200033.25714-3-riel@redhat.com
Signed-off-by: Daniel Micay <danielmicay@gmail.com>
Signed-off-by: Rik van Riel <riel@redhat.com>
Reported-by: Florian Weimer <fweimer@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Daniel Micay <danielmicay@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
When RLIMIT_STACK is, for example, 256MB, the current code results in a
gap between the top of the task and mmap_base of 256MB, failing to take
into account the amount by which the stack address was randomized. In
other words, the stack gets less than RLIMIT_STACK space.
Ensure that the gap between the stack and mmap_base always takes stack
randomization and the stack guard gap into account.
Obtained from Daniel Micay's linux-hardened tree.
Link: http://lkml.kernel.org/r/20170622200033.25714-2-riel@redhat.com
Signed-off-by: Daniel Micay <danielmicay@gmail.com>
Signed-off-by: Rik van Riel <riel@redhat.com>
Reported-by: Florian Weimer <fweimer@redhat.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Daniel Micay <danielmicay@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Use the ascii-armor canary to prevent unterminated C string overflows
from being able to successfully overwrite the canary, even if they
somehow obtain the canary value.
Inspired by execshield ascii-armor and Daniel Micay's linux-hardened
tree.
Link: http://lkml.kernel.org/r/20170524123446.78510066@annuminas.surriel.com
Signed-off-by: Rik van Riel <riel@redhat.com>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Daniel Micay <danielmicay@gmail.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Use the ascii-armor canary to prevent unterminated C string overflows
from being able to successfully overwrite the canary, even if they
somehow obtain the canary value.
Inspired by execshield ascii-armor and Daniel Micay's linux-hardened
tree.
Link: http://lkml.kernel.org/r/20170524155751.424-5-riel@redhat.com
Signed-off-by: Rik van Riel <riel@redhat.com>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Daniel Micay <danielmicay@gmail.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Use the ascii-armor canary to prevent unterminated C string overflows
from being able to successfully overwrite the canary, even if they
somehow obtain the canary value.
Inspired by execshield ascii-armor and Daniel Micay's linux-hardened
tree.
Link: http://lkml.kernel.org/r/20170524155751.424-4-riel@redhat.com
Signed-off-by: Rik van Riel <riel@redhat.com>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Daniel Micay <danielmicay@gmail.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
When building the sh architecture, the compiler doesn't realize that
BUG() doesn't return, so it will complain about functions using BUG()
that are marked with the noreturn attribute:
lib/string.c: In function 'fortify_panic':
>> lib/string.c:986:1: warning: 'noreturn' function does return
}
^
Link: http://lkml.kernel.org/r/20170627192050.GA66784@beast
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Rich Felker <dalias@libc.org>
Cc: Daniel Micay <danielmicay@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
This adds support for compiling with a rough equivalent to the glibc
_FORTIFY_SOURCE=1 feature, providing compile-time and runtime buffer
overflow checks for string.h functions when the compiler determines the
size of the source or destination buffer at compile-time. Unlike glibc,
it covers buffer reads in addition to writes.
GNU C __builtin_*_chk intrinsics are avoided because they would force a
much more complex implementation. They aren't designed to detect read
overflows and offer no real benefit when using an implementation based
on inline checks. Inline checks don't add up to much code size and
allow full use of the regular string intrinsics while avoiding the need
for a bunch of _chk functions and per-arch assembly to avoid wrapper
overhead.
This detects various overflows at compile-time in various drivers and
some non-x86 core kernel code. There will likely be issues caught in
regular use at runtime too.
Future improvements left out of initial implementation for simplicity,
as it's all quite optional and can be done incrementally:
* Some of the fortified string functions (strncpy, strcat), don't yet
place a limit on reads from the source based on __builtin_object_size of
the source buffer.
* Extending coverage to more string functions like strlcat.
* It should be possible to optionally use __builtin_object_size(x, 1) for
some functions (C strings) to detect intra-object overflows (like
glibc's _FORTIFY_SOURCE=2), but for now this takes the conservative
approach to avoid likely compatibility issues.
* The compile-time checks should be made available via a separate config
option which can be enabled by default (or always enabled) once enough
time has passed to get the issues it catches fixed.
Kees said:
"This is great to have. While it was out-of-tree code, it would have
blocked at least CVE-2016-3858 from being exploitable (improper size
argument to strlcpy()). I've sent a number of fixes for
out-of-bounds-reads that this detected upstream already"
[arnd@arndb.de: x86: fix fortified memcpy]
Link: http://lkml.kernel.org/r/20170627150047.660360-1-arnd@arndb.de
[keescook@chromium.org: avoid panic() in favor of BUG()]
Link: http://lkml.kernel.org/r/20170626235122.GA25261@beast
[keescook@chromium.org: move from -mm, add ARCH_HAS_FORTIFY_SOURCE, tweak Kconfig help]
Link: http://lkml.kernel.org/r/20170526095404.20439-1-danielmicay@gmail.com
Link: http://lkml.kernel.org/r/1497903987-21002-8-git-send-email-keescook@chromium.org
Signed-off-by: Daniel Micay <danielmicay@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Daniel Axtens <dja@axtens.net>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Testing the fortified string functions[1] would cause a kernel panic on
boot in test_feature_fixups() due to a buffer overflow in memcmp.
This boils down to things like this:
extern unsigned int ftr_fixup_test1;
extern unsigned int ftr_fixup_test1_orig;
check(memcmp(&ftr_fixup_test1, &ftr_fixup_test1_orig, size) == 0);
We know that these are asm labels so it is safe to read up to 'size'
bytes at those addresses.
However, because we have passed the address of a single unsigned int to
memcmp, the compiler believes the underlying object is in fact a single
unsigned int. So if size > sizeof(unsigned int), there will be a panic
at runtime.
We can fix this by changing the types: instead of calling the asm labels
unsigned ints, call them unsigned int[]s. Therefore the size isn't
incorrectly determined at compile time and we get a regular unsafe
memcmp and no panic.
[1] http://openwall.com/lists/kernel-hardening/2017/05/09/2
Link: http://lkml.kernel.org/r/1497903987-21002-7-git-send-email-keescook@chromium.org
Signed-off-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Kees Cook <keescook@chromium.org>
Suggested-by: Michael Ellerman <mpe@ellerman.id.au>
Tested-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Reviewed-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Daniel Micay <danielmicay@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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prom_init is a bit special; in theory it should be able to be linked
separately to the kernel. To keep this from getting too complex, the
symbols that prom_init.c uses are checked.
Fortification adds symbols, and it gets quite messy as it includes
things like panic(). So just don't fortify prom_init.c for now.
Link: http://lkml.kernel.org/r/1497903987-21002-6-git-send-email-keescook@chromium.org
Signed-off-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Cc: Daniel Micay <danielmicay@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Implement an arch-speicfic watchdog rather than use the perf-based
hardlockup detector.
The new watchdog takes the soft-NMI directly, rather than going through
perf. Perf interrupts are to be made maskable in future, so that would
prevent the perf detector from working in those regions.
Additionally, implement a SMP based detector where all CPUs watch one
another by pinging a shared cpumask. This is because powerpc Book3S
does not have a true periodic local NMI, but some platforms do implement
a true NMI IPI.
If a CPU is stuck with interrupts hard disabled, the soft-NMI watchdog
does not work, but the SMP watchdog will. Even on platforms without a
true NMI IPI to get a good trace from the stuck CPU, other CPUs will
notice the lockup sufficiently to report it and panic.
[npiggin@gmail.com: honor watchdog disable at boot/hotplug]
Link: http://lkml.kernel.org/r/20170621001346.5bb337c9@roar.ozlabs.ibm.com
[npiggin@gmail.com: fix false positive warning at CPU unplug]
Link: http://lkml.kernel.org/r/20170630080740.20766-1-npiggin@gmail.com
[akpm@linux-foundation.org: coding-style fixes]
Link: http://lkml.kernel.org/r/20170616065715.18390-6-npiggin@gmail.com
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Don Zickus <dzickus@redhat.com>
Tested-by: Babu Moger <babu.moger@oracle.com> [sparc]
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Split SOFTLOCKUP_DETECTOR from LOCKUP_DETECTOR, and split
HARDLOCKUP_DETECTOR_PERF from HARDLOCKUP_DETECTOR.
LOCKUP_DETECTOR implies the general boot, sysctl, and programming
interfaces for the lockup detectors.
An architecture that wants to use a hard lockup detector must define
HAVE_HARDLOCKUP_DETECTOR_PERF or HAVE_HARDLOCKUP_DETECTOR_ARCH.
Alternatively an arch can define HAVE_NMI_WATCHDOG, which provides the
minimum arch_touch_nmi_watchdog, and it otherwise does its own thing and
does not implement the LOCKUP_DETECTOR interfaces.
sparc is unusual in that it has started to implement some of the
interfaces, but not fully yet. It should probably be converted to a full
HAVE_HARDLOCKUP_DETECTOR_ARCH.
[npiggin@gmail.com: fix]
Link: http://lkml.kernel.org/r/20170617223522.66c0ad88@roar.ozlabs.ibm.com
Link: http://lkml.kernel.org/r/20170616065715.18390-4-npiggin@gmail.com
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Don Zickus <dzickus@redhat.com>
Reviewed-by: Babu Moger <babu.moger@oracle.com>
Tested-by: Babu Moger <babu.moger@oracle.com> [sparc]
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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For architectures that define HAVE_NMI_WATCHDOG, instead of having them
provide the complete touch_nmi_watchdog() function, just have them
provide arch_touch_nmi_watchdog().
This gives the generic code more flexibility in implementing this
function, and arch implementations don't miss out on touching the
softlockup watchdog or other generic details.
Link: http://lkml.kernel.org/r/20170616065715.18390-3-npiggin@gmail.com
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Don Zickus <dzickus@redhat.com>
Reviewed-by: Babu Moger <babu.moger@oracle.com>
Tested-by: Babu Moger <babu.moger@oracle.com> [sparc]
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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vmcoreinfo_max_size stands for the vmcoreinfo_data, the correct one we
should use is vmcoreinfo_note whose total size is VMCOREINFO_NOTE_SIZE.
Like explained in commit 77019967f06b ("kdump: fix exported size of
vmcoreinfo note"), it should not affect the actual function, but we
better fix it, also this change should be safe and backward compatible.
After this, we can get rid of variable vmcoreinfo_max_size, let's use
the corresponding macros directly, fewer variables means more safety for
vmcoreinfo operation.
[xlpang@redhat.com: fix build warning]
Link: http://lkml.kernel.org/r/1494830606-27736-1-git-send-email-xlpang@redhat.com
Link: http://lkml.kernel.org/r/1493281021-20737-2-git-send-email-xlpang@redhat.com
Signed-off-by: Xunlei Pang <xlpang@redhat.com>
Reviewed-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Reviewed-by: Dave Young <dyoung@redhat.com>
Cc: Hari Bathini <hbathini@linux.vnet.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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