The kernel fails to compile with CONFIG_PROTECTED_VIRTUALIZATION_GUEST
set but CONFIG_KVM unset.
This patch fixes the issue by making the needed variable always available.
Link: https://lkml.kernel.org/r/20200423120114.2027410-1-imbrenda@linux.ibm.com
Fixes: a0f60f8431 ("s390/protvirt: Add sysfs firmware interface for Ultravisor information")
Reported-by: kbuild test robot <lkp@intel.com>
Reported-by: Philipp Rudo <prudo@linux.ibm.com>
Suggested-by: Philipp Rudo <prudo@linux.ibm.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Vasily Gorbik <gor@linux.ibm.com>
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Switching tracers include instruction patching. To prevent that a
instruction is patched while it's read the instruction patching is done
in stop_machine 'context'. This also means that any function called
during stop_machine must not be traced. Thus add 'notrace' to all
functions called within stop_machine.
Fixes: 1ec2772e0c ("s390/diag: add a statistic for diagnose calls")
Fixes: 38f2c691a4 ("s390: improve wait logic of stop_machine")
Fixes: 4ecf0a43e7 ("processor: get rid of cpu_relax_yield")
Signed-off-by: Philipp Rudo <prudo@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
- Update maintainers. Niklas Schnelle takes over zpci and Vineeth Vijayan
common io code.
- Extend cpuinfo to include topology information.
- Add new extended counters for IBM z15 and sampling buffer allocation
rework in perf code.
- Add control over zeroing out memory during system restart.
- CCA protected key block version 2 support and other fixes/improvements
in crypto code.
- Convert to new fallthrough; annotations.
- Replace zero-length arrays with flexible-arrays.
- QDIO debugfs and other small improvements.
- Drop 2-level paging support optimization for compat tasks. Varios
mm cleanups.
- Remove broken and unused hibernate / power management support.
- Remove fake numa support which does not bring any benefits.
- Exclude offline CPUs from CPU topology masks to be more consistent
with other architectures.
- Prevent last branching instruction address leaking to userspace.
- Other small various fixes and improvements all over the code.
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Merge tag 's390-5.7-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux
Pull s390 updates from Vasily Gorbik:
- Update maintainers. Niklas Schnelle takes over zpci and Vineeth
Vijayan common io code.
- Extend cpuinfo to include topology information.
- Add new extended counters for IBM z15 and sampling buffer allocation
rework in perf code.
- Add control over zeroing out memory during system restart.
- CCA protected key block version 2 support and other
fixes/improvements in crypto code.
- Convert to new fallthrough; annotations.
- Replace zero-length arrays with flexible-arrays.
- QDIO debugfs and other small improvements.
- Drop 2-level paging support optimization for compat tasks. Varios mm
cleanups.
- Remove broken and unused hibernate / power management support.
- Remove fake numa support which does not bring any benefits.
- Exclude offline CPUs from CPU topology masks to be more consistent
with other architectures.
- Prevent last branching instruction address leaking to userspace.
- Other small various fixes and improvements all over the code.
* tag 's390-5.7-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (57 commits)
s390/mm: cleanup init_new_context() callback
s390/mm: cleanup virtual memory constants usage
s390/mm: remove page table downgrade support
s390/qdio: set qdio_irq->cdev at allocation time
s390/qdio: remove unused function declarations
s390/ccwgroup: remove pm support
s390/ap: remove power management code from ap bus and drivers
s390/zcrypt: use kvmalloc instead of kmalloc for 256k alloc
s390/mm: cleanup arch_get_unmapped_area() and friends
s390/ism: remove pm support
s390/cio: use fallthrough;
s390/vfio: use fallthrough;
s390/zcrypt: use fallthrough;
s390: use fallthrough;
s390/cpum_sf: Fix wrong page count in error message
s390/diag: fix display of diagnose call statistics
s390/ap: Remove ap device suspend and resume callbacks
s390/pci: Improve handling of unset UID
s390/pci: Fix zpci_alloc_domain() over allocation
s390/qdio: pass ISC as parameter to chsc_sadc()
...
Here are 3 SPDX patches for 5.7-rc1.
One fixes up the SPDX tag for a single driver, while the other two go
through the tree and add SPDX tags for all of the .gitignore files as
needed.
Nothing too complex, but you will get a merge conflict with your current
tree, that should be trivial to handle (one file modified by two things,
one file deleted.)
All 3 of these have been in linux-next for a while, with no reported
issues other than the merge conflict.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'spdx-5.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/spdx
Pull SPDX updates from Greg KH:
"Here are three SPDX patches for 5.7-rc1.
One fixes up the SPDX tag for a single driver, while the other two go
through the tree and add SPDX tags for all of the .gitignore files as
needed.
Nothing too complex, but you will get a merge conflict with your
current tree, that should be trivial to handle (one file modified by
two things, one file deleted.)
All three of these have been in linux-next for a while, with no
reported issues other than the merge conflict"
* tag 'spdx-5.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/spdx:
ASoC: MT6660: make spdxcheck.py happy
.gitignore: add SPDX License Identifier
.gitignore: remove too obvious comments
* GICv4.1 support
* 32bit host removal
PPC:
* secure (encrypted) using under the Protected Execution Framework
ultravisor
s390:
* allow disabling GISA (hardware interrupt injection) and protected
VMs/ultravisor support.
x86:
* New dirty bitmap flag that sets all bits in the bitmap when dirty
page logging is enabled; this is faster because it doesn't require bulk
modification of the page tables.
* Initial work on making nested SVM event injection more similar to VMX,
and less buggy.
* Various cleanups to MMU code (though the big ones and related
optimizations were delayed to 5.8). Instead of using cr3 in function
names which occasionally means eptp, KVM too has standardized on "pgd".
* A large refactoring of CPUID features, which now use an array that
parallels the core x86_features.
* Some removal of pointer chasing from kvm_x86_ops, which will also be
switched to static calls as soon as they are available.
* New Tigerlake CPUID features.
* More bugfixes, optimizations and cleanups.
Generic:
* selftests: cleanups, new MMU notifier stress test, steal-time test
* CSV output for kvm_stat.
KVM/MIPS has been broken since 5.5, it does not compile due to a patch committed
by MIPS maintainers. I had already prepared a fix, but the MIPS maintainers
prefer to fix it in generic code rather than KVM so they are taking care of it.
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull kvm updates from Paolo Bonzini:
"ARM:
- GICv4.1 support
- 32bit host removal
PPC:
- secure (encrypted) using under the Protected Execution Framework
ultravisor
s390:
- allow disabling GISA (hardware interrupt injection) and protected
VMs/ultravisor support.
x86:
- New dirty bitmap flag that sets all bits in the bitmap when dirty
page logging is enabled; this is faster because it doesn't require
bulk modification of the page tables.
- Initial work on making nested SVM event injection more similar to
VMX, and less buggy.
- Various cleanups to MMU code (though the big ones and related
optimizations were delayed to 5.8). Instead of using cr3 in
function names which occasionally means eptp, KVM too has
standardized on "pgd".
- A large refactoring of CPUID features, which now use an array that
parallels the core x86_features.
- Some removal of pointer chasing from kvm_x86_ops, which will also
be switched to static calls as soon as they are available.
- New Tigerlake CPUID features.
- More bugfixes, optimizations and cleanups.
Generic:
- selftests: cleanups, new MMU notifier stress test, steal-time test
- CSV output for kvm_stat"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (277 commits)
x86/kvm: fix a missing-prototypes "vmread_error"
KVM: x86: Fix BUILD_BUG() in __cpuid_entry_get_reg() w/ CONFIG_UBSAN=y
KVM: VMX: Add a trampoline to fix VMREAD error handling
KVM: SVM: Annotate svm_x86_ops as __initdata
KVM: VMX: Annotate vmx_x86_ops as __initdata
KVM: x86: Drop __exit from kvm_x86_ops' hardware_unsetup()
KVM: x86: Copy kvm_x86_ops by value to eliminate layer of indirection
KVM: x86: Set kvm_x86_ops only after ->hardware_setup() completes
KVM: VMX: Configure runtime hooks using vmx_x86_ops
KVM: VMX: Move hardware_setup() definition below vmx_x86_ops
KVM: x86: Move init-only kvm_x86_ops to separate struct
KVM: Pass kvm_init()'s opaque param to additional arch funcs
s390/gmap: return proper error code on ksm unsharing
KVM: selftests: Fix cosmetic copy-paste error in vm_mem_region_move()
KVM: Fix out of range accesses to memslots
KVM: X86: Micro-optimize IPI fastpath delay
KVM: X86: Delay read msr data iff writes ICR MSR
KVM: PPC: Book3S HV: Add a capability for enabling secure guests
KVM: arm64: GICv4.1: Expose HW-based SGIs in debugfs
KVM: arm64: GICv4.1: Allow non-trapping WFI when using HW SGIs
...
When perf record -e SF_CYCLES_BASIC_DIAG runs with very high
frequency, the samples arrive faster than the perf process can
save them to file. Eventually, for longer running processes, this
leads to the siutation where the trace buffers allocated by perf
slowly fills up. At one point the auxiliary trace buffer is full
and the CPU Measurement sampling facility is turned off. Furthermore
a warning is printed to the kernel log buffer:
cpum_sf: The AUX buffer with 0 pages for the diagnostic-sampling
mode is full
The number of allocated pages for the auxiliary trace buffer is shown
as zero pages. That is wrong.
Fix this by saving the number of allocated pages before entering the
work loop in the interrupt handler. When the interrupt handler processes
the samples, it may detect the buffer full condition and stop sampling,
reducing the buffer size to zero.
Print the correct value in the error message:
cpum_sf: The AUX buffer with 256 pages for the diagnostic-sampling
mode is full
Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Show the full diag statistic table and not just parts of it.
The issue surfaced in a KVM guest with a number of vcpus
defined smaller than NR_DIAG_STAT.
Fixes: 1ec2772e0c ("s390/diag: add a statistic for diagnose calls")
Cc: stable@vger.kernel.org
Signed-off-by: Michael Mueller <mimu@linux.ibm.com>
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Hibernation is known to be broken for many years on s390. Given that
there aren't any real use cases, remove the code instead of spending
time to fix and maintain it.
Without hibernate support it doesn't make too much sense to keep power
management support; therefore remove it completely.
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Acked-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
In the past there were no per-CPU information in /proc/cpuinfo
other than CPU frequency. Hence, for machines without CPU MHz
feature there were nothing to show. Now CPU topology and IDs
still could be shown, so do not skip this information from the
output.
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
[heiko.carstens@de.ibm.com: moved comparison]
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
/proc/cpuinfo should not print information about CPU 0 when it is offline.
Fixes: 281eaa8cb6 ("s390/cpuinfo: simplify locking and skip offline cpus early")
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
[heiko.carstens@de.ibm.com: shortened commit message]
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Show number of online CPUs within a package (which is
the socket in case of s390). For what it worth, present
that value as "siblings" field - just like x86 does.
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Show number of cores that run at least one SMT thread
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Re-IPL for both CCW and FCP is currently done by using diag 308 with the
"Load Clear" subcode, which means that all memory will be cleared.
This can increase re-IPL duration considerably on very large machines.
For CCW devices, there is also a "Load Normal" subcode that was only used
for dump kernels so far. For FCP devices, a similar "Load Normal" subcode
was introduced with z14. The "Load Normal" diag 308 subcode allows to
re-IPL without clearing memory.
This patch adds a new "clear" sysfs attribute to /sys/firmware/reipl for
both the ccw and fcp subdirectories, which can be set to either "0" or "1"
to disable or enable re-IPL with memory clearing. The default value is "0",
which disables memory clearing.
Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
The CPU topology masks on s390 contain also bits of CPUs which
are offline. Currently this is already a problem, since common
code scheduler expects e.g. cpu_smt_mask() to reflect reality.
This update changes the described behaviour and s390 starts to
behave like all other architectures.
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Variable cpus_with_topology is a leftover that became
unneeded once the fake NUMA support has been removed.
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Show CPU physical address as reported by STAP instruction
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Every time a new architecture defines the IMA architecture specific
functions - arch_ima_get_secureboot() and arch_ima_get_policy(), the IMA
include file needs to be updated. To avoid this "noise", this patch
defines a new IMA Kconfig IMA_SECURE_AND_OR_TRUSTED_BOOT option, allowing
the different architectures to select it.
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Nayna Jain <nayna@linux.ibm.com>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Philipp Rudo <prudo@linux.ibm.com> (s390)
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
request_irq() is preferred over setup_irq(). Invocations of setup_irq()
occur after memory allocators are ready.
Per tglx[1], setup_irq() existed in olden days when allocators were not
ready by the time early interrupts were initialized.
Hence replace setup_irq() by request_irq().
[1] https://lkml.kernel.org/r/alpine.DEB.2.20.1710191609480.1971@nanos
Signed-off-by: afzal mohammed <afzal.mohd.ma@gmail.com>
Message-Id: <20200304005049.5291-1-afzal.mohd.ma@gmail.com>
[heiko.carstens@de.ibm.com: replace pr_err with panic]
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
This update adjusts /proc/cpuinfo format to meet some user level
programs expectations. It also makes the layout consistent with
x86 where CPU topology is presented as blocks of key-value pairs.
Reviewed-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
When userspace executes a syscall or gets interrupted,
BEAR contains a kernel address when returning to userspace.
This make it pretty easy to figure out where the kernel is
mapped even with KASLR enabled. To fix this, add lpswe to
lowcore and always execute it there, so userspace sees only
the lowcore address of lpswe. For this we have to extend
both critical_cleanup and the SWITCH_ASYNC macro to also check
for lpswe addresses in lowcore.
Fixes: b2d24b97b2 ("s390/kernel: add support for kernel address space layout randomization (KASLR)")
Cc: <stable@vger.kernel.org> # v5.2+
Reviewed-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
That information, e.g. the maximum number of guests or installed
Ultravisor facilities, is interesting for QEMU, Libvirt and
administrators.
Let's provide an easily parsable API to get that information.
Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
This provides the basic ultravisor calls and page table handling to cope
with secure guests:
- provide arch_make_page_accessible
- make pages accessible after unmapping of secure guests
- provide the ultravisor commands convert to/from secure
- provide the ultravisor commands pin/unpin shared
- provide callbacks to make pages secure (inacccessible)
- we check for the expected pin count to only make pages secure if the
host is not accessing them
- we fence hugetlbfs for secure pages
- add missing radix-tree include into gmap.h
The basic idea is that a page can have 3 states: secure, normal or
shared. The hypervisor can call into a firmware function called
ultravisor that allows to change the state of a page: convert from/to
secure. The convert from secure will encrypt the page and make it
available to the host and host I/O. The convert to secure will remove
the host capability to access this page.
The design is that on convert to secure we will wait until writeback and
page refs are indicating no host usage. At the same time the convert
from secure (export to host) will be called in common code when the
refcount or the writeback bit is already set. This avoids races between
convert from and to secure.
Then there is also the concept of shared pages. Those are kind of secure
where the host can still access those pages. We need to be notified when
the guest "unshares" such a page, basically doing a convert to secure by
then. There is a call "pin shared page" that we use instead of convert
from secure when possible.
We do use PG_arch_1 as an optimization to minimize the convert from
secure/pin shared.
Several comments have been added in the code to explain the logic in
the relevant places.
Co-developed-by: Ulrich Weigand <Ulrich.Weigand@de.ibm.com>
Signed-off-by: Ulrich Weigand <Ulrich.Weigand@de.ibm.com>
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
[borntraeger@de.ibm.com: patch merging, splitting, fixing]
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Before being able to host protected virtual machines, donate some of
the memory to the ultravisor. Besides that the ultravisor might impose
addressing limitations for memory used to back protected VM storage. Treat
that limit as protected virtualization host's virtual memory limit.
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
[borntraeger@de.ibm.com: patch merging, splitting, fixing]
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Add "prot_virt" command line option which controls if the kernel
protected VMs support is enabled at early boot time. This has to be
done early, because it needs large amounts of memory and will disable
some features like STP time sync for the lpar.
Extend ultravisor info definitions and expose it via uv_info struct
filled in during startup.
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
[borntraeger@de.ibm.com: patch merging, splitting, fixing]
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
It turned out that fake numa support is rather useless on s390, since
there are no scenarios where there is any performance or other benefit
when used.
However it does provide maintenance cost and breaks from time to time.
Therefore remove it.
CONFIG_NUMA is still supported with a very small backend and only one
node. This way userspace applications which require NUMA interfaces
continue to work.
Note that NODES_SHIFT is set to 1 (= 2 nodes) instead of 0 (= 1 node),
since there is quite a bit of kernel code which assumes that more than
one node is possible if CONFIG_NUMA is enabled.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Adjust sampling buffer allocation depending on
frequency and correct comments. Investigation on the
interrupt handler revealed that almost always one interupt
services one SDB, even when running with the maximum frequency
of 100000. Very rarely there have been 2 SBD serviced per
interrupt.
Therefore reduce the number of SBD per CPU. Each SDB is one
page in size. The new formula results in
freq:4000 n_sdb:32 new:16
freq:10000 n_sdb:80 new:16
freq:20000 n_sdb:159 new:17
freq:40000 n_sdb:318 new:19
freq:50000 n_sdb:397 new:20
freq:62500 n_sdb:497 new:22
freq:83333 n_sdb:662 new:24
freq:100000 n_sdb:794 new:25
Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
- Add KPROBES_ON_FTRACE support.
- Add EP11 AES secure keys support.
- PAES rework and prerequisites for paes-s390 ciphers selftests.
- Fix page table upgrade for hugetlbfs.
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Merge tag 's390-5.6-2' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux
Pull more s390 updates from Vasily Gorbik:
"The second round of s390 fixes and features for 5.6:
- Add KPROBES_ON_FTRACE support
- Add EP11 AES secure keys support
- PAES rework and prerequisites for paes-s390 ciphers selftests
- Fix page table upgrade for hugetlbfs"
* tag 's390-5.6-2' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
s390/pkey/zcrypt: Support EP11 AES secure keys
s390/zcrypt: extend EP11 card and queue sysfs attributes
s390/zcrypt: add new low level ep11 functions support file
s390/zcrypt: ep11 structs rework, export zcrypt_send_ep11_cprb
s390/zcrypt: enable card/domain autoselect on ep11 cprbs
s390/crypto: enable clear key values for paes ciphers
s390/pkey: Add support for key blob with clear key value
s390/crypto: Rework on paes implementation
s390: support KPROBES_ON_FTRACE
s390/mm: fix dynamic pagetable upgrade for hugetlbfs
Add the new kernel command line parameter 'dfltcc=' to configure s390
zlib hardware support.
Format: { on | off | def_only | inf_only | always }
on: s390 zlib hardware support for compression on
level 1 and decompression (default)
off: No s390 zlib hardware support
def_only: s390 zlib hardware support for deflate
only (compression on level 1)
inf_only: s390 zlib hardware support for inflate
only (decompression)
always: Same as 'on' but ignores the selected compression
level always using hardware support (used for debugging)
Link: http://lkml.kernel.org/r/20200103223334.20669-5-zaslonko@linux.ibm.com
Signed-off-by: Mikhail Zaslonko <zaslonko@linux.ibm.com>
Cc: Chris Mason <clm@fb.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: David Sterba <dsterba@suse.com>
Cc: Eduard Shishkin <edward6@linux.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Ilya Leoshkevich <iii@linux.ibm.com>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
On the s390 platform memblock.physmem array is being built by directly
calling into memblock_add_range() which is a low level function not
intended to be used outside of memblock. Hence lets conditionally add
helper functions for physmem array when HAVE_MEMBLOCK_PHYS_MAP is
enabled. Also use MAX_NUMNODES instead of 0 as node ID similar to
memblock_add() and memblock_reserve(). Make memblock_add_range() a
static function as it is no longer getting used outside of memblock.
Link: http://lkml.kernel.org/r/1578283835-21969-1-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Mike Rapoport <rppt@linux.ibm.com>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Collin Walling <walling@linux.ibm.com>
Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Cc: Philipp Rudo <prudo@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Instead of using our own kprobes-on-ftrace handling convert the
code to support KPROBES_ON_FTRACE.
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
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Merge tag 'threads-v5.6' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux
Pull thread management updates from Christian Brauner:
"Sargun Dhillon over the last cycle has worked on the pidfd_getfd()
syscall.
This syscall allows for the retrieval of file descriptors of a process
based on its pidfd. A task needs to have ptrace_may_access()
permissions with PTRACE_MODE_ATTACH_REALCREDS (suggested by Oleg and
Andy) on the target.
One of the main use-cases is in combination with seccomp's user
notification feature. As a reminder, seccomp's user notification
feature was made available in v5.0. It allows a task to retrieve a
file descriptor for its seccomp filter. The file descriptor is usually
handed of to a more privileged supervising process. The supervisor can
then listen for syscall events caught by the seccomp filter of the
supervisee and perform actions in lieu of the supervisee, usually
emulating syscalls. pidfd_getfd() is needed to expand its uses.
There are currently two major users that wait on pidfd_getfd() and one
future user:
- Netflix, Sargun said, is working on a service mesh where users
should be able to connect to a dns-based VIP. When a user connects
to e.g. 1.2.3.4:80 that runs e.g. service "foo" they will be
redirected to an envoy process. This service mesh uses seccomp user
notifications and pidfd to intercept all connect calls and instead
of connecting them to 1.2.3.4:80 connects them to e.g.
127.0.0.1:8080.
- LXD uses the seccomp notifier heavily to intercept and emulate
mknod() and mount() syscalls for unprivileged containers/processes.
With pidfd_getfd() more uses-cases e.g. bridging socket connections
will be possible.
- The patchset has also seen some interest from the browser corner.
Right now, Firefox is using a SECCOMP_RET_TRAP sandbox managed by a
broker process. In the future glibc will start blocking all signals
during dlopen() rendering this type of sandbox impossible. Hence,
in the future Firefox will switch to a seccomp-user-nofication
based sandbox which also makes use of file descriptor retrieval.
The thread for this can be found at
https://sourceware.org/ml/libc-alpha/2019-12/msg00079.html
With pidfd_getfd() it is e.g. possible to bridge socket connections
for the supervisee (binding to a privileged port) and taking actions
on file descriptors on behalf of the supervisee in general.
Sargun's first version was using an ioctl on pidfds but various people
pushed for it to be a proper syscall which he duely implemented as
well over various review cycles. Selftests are of course included.
I've also added instructions how to deal with merge conflicts below.
There's also a small fix coming from the kernel mentee project to
correctly annotate struct sighand_struct with __rcu to fix various
sparse warnings. We've received a few more such fixes and even though
they are mostly trivial I've decided to postpone them until after -rc1
since they came in rather late and I don't want to risk introducing
build warnings.
Finally, there's a new prctl() command PR_{G,S}ET_IO_FLUSHER which is
needed to avoid allocation recursions triggerable by storage drivers
that have userspace parts that run in the IO path (e.g. dm-multipath,
iscsi, etc). These allocation recursions deadlock the device.
The new prctl() allows such privileged userspace components to avoid
allocation recursions by setting the PF_MEMALLOC_NOIO and
PF_LESS_THROTTLE flags. The patch carries the necessary acks from the
relevant maintainers and is routed here as part of prctl()
thread-management."
* tag 'threads-v5.6' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux:
prctl: PR_{G,S}ET_IO_FLUSHER to support controlling memory reclaim
sched.h: Annotate sighand_struct with __rcu
test: Add test for pidfd getfd
arch: wire up pidfd_getfd syscall
pid: Implement pidfd_getfd syscall
vfs, fdtable: Add fget_task helper
Pull openat2 support from Al Viro:
"This is the openat2() series from Aleksa Sarai.
I'm afraid that the rest of namei stuff will have to wait - it got
zero review the last time I'd posted #work.namei, and there had been a
leak in the posted series I'd caught only last weekend. I was going to
repost it on Monday, but the window opened and the odds of getting any
review during that... Oh, well.
Anyway, openat2 part should be ready; that _did_ get sane amount of
review and public testing, so here it comes"
From Aleksa's description of the series:
"For a very long time, extending openat(2) with new features has been
incredibly frustrating. This stems from the fact that openat(2) is
possibly the most famous counter-example to the mantra "don't silently
accept garbage from userspace" -- it doesn't check whether unknown
flags are present[1].
This means that (generally) the addition of new flags to openat(2) has
been fraught with backwards-compatibility issues (O_TMPFILE has to be
defined as __O_TMPFILE|O_DIRECTORY|[O_RDWR or O_WRONLY] to ensure old
kernels gave errors, since it's insecure to silently ignore the
flag[2]). All new security-related flags therefore have a tough road
to being added to openat(2).
Furthermore, the need for some sort of control over VFS's path
resolution (to avoid malicious paths resulting in inadvertent
breakouts) has been a very long-standing desire of many userspace
applications.
This patchset is a revival of Al Viro's old AT_NO_JUMPS[3] patchset
(which was a variant of David Drysdale's O_BENEATH patchset[4] which
was a spin-off of the Capsicum project[5]) with a few additions and
changes made based on the previous discussion within [6] as well as
others I felt were useful.
In line with the conclusions of the original discussion of
AT_NO_JUMPS, the flag has been split up into separate flags. However,
instead of being an openat(2) flag it is provided through a new
syscall openat2(2) which provides several other improvements to the
openat(2) interface (see the patch description for more details). The
following new LOOKUP_* flags are added:
LOOKUP_NO_XDEV:
Blocks all mountpoint crossings (upwards, downwards, or through
absolute links). Absolute pathnames alone in openat(2) do not
trigger this. Magic-link traversal which implies a vfsmount jump is
also blocked (though magic-link jumps on the same vfsmount are
permitted).
LOOKUP_NO_MAGICLINKS:
Blocks resolution through /proc/$pid/fd-style links. This is done
by blocking the usage of nd_jump_link() during resolution in a
filesystem. The term "magic-links" is used to match with the only
reference to these links in Documentation/, but I'm happy to change
the name.
It should be noted that this is different to the scope of
~LOOKUP_FOLLOW in that it applies to all path components. However,
you can do openat2(NO_FOLLOW|NO_MAGICLINKS) on a magic-link and it
will *not* fail (assuming that no parent component was a
magic-link), and you will have an fd for the magic-link.
In order to correctly detect magic-links, the introduction of a new
LOOKUP_MAGICLINK_JUMPED state flag was required.
LOOKUP_BENEATH:
Disallows escapes to outside the starting dirfd's
tree, using techniques such as ".." or absolute links. Absolute
paths in openat(2) are also disallowed.
Conceptually this flag is to ensure you "stay below" a certain
point in the filesystem tree -- but this requires some additional
to protect against various races that would allow escape using
"..".
Currently LOOKUP_BENEATH implies LOOKUP_NO_MAGICLINKS, because it
can trivially beam you around the filesystem (breaking the
protection). In future, there might be similar safety checks done
as in LOOKUP_IN_ROOT, but that requires more discussion.
In addition, two new flags are added that expand on the above ideas:
LOOKUP_NO_SYMLINKS:
Does what it says on the tin. No symlink resolution is allowed at
all, including magic-links. Just as with LOOKUP_NO_MAGICLINKS this
can still be used with NOFOLLOW to open an fd for the symlink as
long as no parent path had a symlink component.
LOOKUP_IN_ROOT:
This is an extension of LOOKUP_BENEATH that, rather than blocking
attempts to move past the root, forces all such movements to be
scoped to the starting point. This provides chroot(2)-like
protection but without the cost of a chroot(2) for each filesystem
operation, as well as being safe against race attacks that
chroot(2) is not.
If a race is detected (as with LOOKUP_BENEATH) then an error is
generated, and similar to LOOKUP_BENEATH it is not permitted to
cross magic-links with LOOKUP_IN_ROOT.
The primary need for this is from container runtimes, which
currently need to do symlink scoping in userspace[7] when opening
paths in a potentially malicious container.
There is a long list of CVEs that could have bene mitigated by
having RESOLVE_THIS_ROOT (such as CVE-2017-1002101,
CVE-2017-1002102, CVE-2018-15664, and CVE-2019-5736, just to name a
few).
In order to make all of the above more usable, I'm working on
libpathrs[8] which is a C-friendly library for safe path resolution.
It features a userspace-emulated backend if the kernel doesn't support
openat2(2). Hopefully we can get userspace to switch to using it, and
thus get openat2(2) support for free once it's ready.
Future work would include implementing things like
RESOLVE_NO_AUTOMOUNT and possibly a RESOLVE_NO_REMOTE (to allow
programs to be sure they don't hit DoSes though stale NFS handles)"
* 'work.openat2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
Documentation: path-lookup: include new LOOKUP flags
selftests: add openat2(2) selftests
open: introduce openat2(2) syscall
namei: LOOKUP_{IN_ROOT,BENEATH}: permit limited ".." resolution
namei: LOOKUP_IN_ROOT: chroot-like scoped resolution
namei: LOOKUP_BENEATH: O_BENEATH-like scoped resolution
namei: LOOKUP_NO_XDEV: block mountpoint crossing
namei: LOOKUP_NO_MAGICLINKS: block magic-link resolution
namei: LOOKUP_NO_SYMLINKS: block symlink resolution
namei: allow set_root() to produce errors
namei: allow nd_jump_link() to produce errors
nsfs: clean-up ns_get_path() signature to return int
namei: only return -ECHILD from follow_dotdot_rcu()
Here are the big set of tty and serial driver updates for 5.6-rc1
Included in here are:
- dummy_con cleanups (touches lots of arch code)
- sysrq logic cleanups (touches lots of serial drivers)
- samsung driver fixes (wasn't really being built)
- conmakeshash move to tty subdir out of scripts
- lots of small tty/serial driver updates
All of these have been in linux-next for a while with no reported
issues.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'tty-5.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty
Pull tty/serial driver updates from Greg KH:
"Here are the big set of tty and serial driver updates for 5.6-rc1
Included in here are:
- dummy_con cleanups (touches lots of arch code)
- sysrq logic cleanups (touches lots of serial drivers)
- samsung driver fixes (wasn't really being built)
- conmakeshash move to tty subdir out of scripts
- lots of small tty/serial driver updates
All of these have been in linux-next for a while with no reported
issues"
* tag 'tty-5.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (140 commits)
tty: n_hdlc: Use flexible-array member and struct_size() helper
tty: baudrate: SPARC supports few more baud rates
tty: baudrate: Synchronise baud_table[] and baud_bits[]
tty: serial: meson_uart: Add support for kernel debugger
serial: imx: fix a race condition in receive path
serial: 8250_bcm2835aux: Document struct bcm2835aux_data
serial: 8250_bcm2835aux: Use generic remapping code
serial: 8250_bcm2835aux: Allocate uart_8250_port on stack
serial: 8250_bcm2835aux: Suppress register_port error on -EPROBE_DEFER
serial: 8250_bcm2835aux: Suppress clk_get error on -EPROBE_DEFER
serial: 8250_bcm2835aux: Fix line mismatch on driver unbind
serial_core: Remove unused member in uart_port
vt: Correct comment documenting do_take_over_console()
vt: Delete comment referencing non-existent unbind_con_driver()
arch/xtensa/setup: Drop dummy_con initialization
arch/x86/setup: Drop dummy_con initialization
arch/unicore32/setup: Drop dummy_con initialization
arch/sparc/setup: Drop dummy_con initialization
arch/sh/setup: Drop dummy_con initialization
arch/s390/setup: Drop dummy_con initialization
...
- Add clang 10 build support.
- Fix BUG() implementation to contain precise bug address, which is
relevant for kprobes.
- Make ftraced function appear in a stacktrace.
- Minor perf improvements and refactoring.
- Possible deadlock and recovery fixes in pci code.
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Merge tag 's390-5.6-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux
Pull s390 updates from Vasily Gorbik:
- Add clang 10 build support.
- Fix BUG() implementation to contain precise bug address, which is
relevant for kprobes.
- Make ftraced function appear in a stacktrace.
- Minor perf improvements and refactoring.
- Possible deadlock and recovery fixes in pci code.
* tag 's390-5.6-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
s390: fix __EMIT_BUG() macro
s390/ftrace: generate traced function stack frame
s390: adjust -mpacked-stack support check for clang 10
s390/jump_label: use "i" constraint for clang
s390/cpum_sf: Use DIV_ROUND_UP
s390/cpum_sf: Use kzalloc and minor changes
s390/cpum_sf: Convert debug trace to common layout
s390/pci: Fix possible deadlock in recover_store()
s390/pci: Recover handle in clp_set_pci_fn()
Pull scheduler updates from Ingo Molnar:
"These were the main changes in this cycle:
- More -rt motivated separation of CONFIG_PREEMPT and
CONFIG_PREEMPTION.
- Add more low level scheduling topology sanity checks and warnings
to filter out nonsensical topologies that break scheduling.
- Extend uclamp constraints to influence wakeup CPU placement
- Make the RT scheduler more aware of asymmetric topologies and CPU
capacities, via uclamp metrics, if CONFIG_UCLAMP_TASK=y
- Make idle CPU selection more consistent
- Various fixes, smaller cleanups, updates and enhancements - please
see the git log for details"
* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (58 commits)
sched/fair: Define sched_idle_cpu() only for SMP configurations
sched/topology: Assert non-NUMA topology masks don't (partially) overlap
idle: fix spelling mistake "iterrupts" -> "interrupts"
sched/fair: Remove redundant call to cpufreq_update_util()
sched/psi: create /proc/pressure and /proc/pressure/{io|memory|cpu} only when psi enabled
sched/fair: Fix sgc->{min,max}_capacity calculation for SD_OVERLAP
sched/fair: calculate delta runnable load only when it's needed
sched/cputime: move rq parameter in irqtime_account_process_tick
stop_machine: Make stop_cpus() static
sched/debug: Reset watchdog on all CPUs while processing sysrq-t
sched/core: Fix size of rq::uclamp initialization
sched/uclamp: Fix a bug in propagating uclamp value in new cgroups
sched/fair: Load balance aggressively for SCHED_IDLE CPUs
sched/fair : Improve update_sd_pick_busiest for spare capacity case
watchdog: Remove soft_lockup_hrtimer_cnt and related code
sched/rt: Make RT capacity-aware
sched/fair: Make EAS wakeup placement consider uclamp restrictions
sched/fair: Make task_fits_capacity() consider uclamp restrictions
sched/uclamp: Rename uclamp_util_with() into uclamp_rq_util_with()
sched/uclamp: Make uclamp util helpers use and return UL values
...
Setting a kprobe on getname_flags() failed:
$ echo 'p:tmr1 getname_flags +0(%r2):ustring' > kprobe_events
-bash: echo: write error: Invalid argument
Debugging the kprobes code showed that the address of
getname_flags() is contained in the __bug_table. Kprobes
doesn't allow to set probes at BUG() locations.
$ objdump -j __bug_table -x build/fs/namei.o
[..]
0000000000000108 R_390_PC32 .text+0x00000000000075a8
000000000000010c R_390_PC32 .L223+0x0000000000000004
I was expecting getname_flags() to start with a BUG(), but:
7598: e3 20 10 00 00 04 lg %r2,0(%r1)
759e: c0 f4 00 00 00 00 jg 759e <putname+0x7e>
75a0: R_390_PLT32DBL kmem_cache_free+0x2
75a4: a7 f4 00 01 j 75a6 <putname+0x86>
00000000000075a8 <getname_flags>:
75a8: c0 04 00 00 00 00 brcl 0,75a8 <getname_flags>
75ae: eb 6f f0 48 00 24 stmg %r6,%r15,72(%r15)
75b4: b9 04 00 ef lgr %r14,%r15
75b8: e3 f0 ff a8 ff 71 lay %r15,-88(%r15)
So the BUG() is actually the last opcode of the previous function.
Fix this by switching to using the MONITOR CALL (MC) instruction,
and set the entry in __bug_table to the beginning of that MC.
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Currently backtrace from ftraced function does not contain ftraced
function itself. e.g. for "path_openat":
arch_stack_walk+0x15c/0x2d8
stack_trace_save+0x50/0x68
stack_trace_call+0x15e/0x3d8
ftrace_graph_caller+0x0/0x1c <-- ftrace code
do_filp_open+0x7c/0xe8 <-- ftraced function caller
do_open_execat+0x76/0x1b8
open_exec+0x52/0x78
load_elf_binary+0x180/0x1160
search_binary_handler+0x8e/0x288
load_script+0x2a8/0x2b8
search_binary_handler+0x8e/0x288
__do_execve_file.isra.39+0x6fa/0xb40
__s390x_sys_execve+0x56/0x68
system_call+0xdc/0x2d8
Ftraced function is expected in the backtrace by ftrace kselftests, which
are now failing. It would also be nice to have it for clarity reasons.
"ftrace_caller" itself is called without stack frame allocated for it
and does not store its caller (ftraced function). Instead it simply
allocates a stack frame for "ftrace_trace_function" and sets backchain
to point to ftraced function stack frame (which contains ftraced function
caller in saved r14).
To fix this issue make "ftrace_caller" allocate a stack frame
for itself just to store ftraced function for the stack unwinder.
As a result backtrace looks like the following:
arch_stack_walk+0x15c/0x2d8
stack_trace_save+0x50/0x68
stack_trace_call+0x15e/0x3d8
ftrace_graph_caller+0x0/0x1c <-- ftrace code
path_openat+0x6/0xd60 <-- ftraced function
do_filp_open+0x7c/0xe8 <-- ftraced function caller
do_open_execat+0x76/0x1b8
open_exec+0x52/0x78
load_elf_binary+0x180/0x1160
search_binary_handler+0x8e/0x288
load_script+0x2a8/0x2b8
search_binary_handler+0x8e/0x288
__do_execve_file.isra.39+0x6fa/0xb40
__s390x_sys_execve+0x56/0x68
system_call+0xdc/0x2d8
Reported-by: Sven Schnelle <sven.schnelle@ibm.com>
Tested-by: Sven Schnelle <sven.schnelle@ibm.com>
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Use macro DIV_ROUND_UP() for calculation of number of SDBT
SDBT pages required for index pages. This macro is already
used throughout the file.
Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Use kzalloc() to allocate auxiliary buffer structure initialized
with all zeroes to avoid random value in trace output.
Avoid double access to SBD hardware flags.
Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Convert debug traces to print the head/alert/empty marks
consistently as decimal numbers. Add some trace statements
to enable easier debugging during auxiliary tracing.
Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
/* Background. */
For a very long time, extending openat(2) with new features has been
incredibly frustrating. This stems from the fact that openat(2) is
possibly the most famous counter-example to the mantra "don't silently
accept garbage from userspace" -- it doesn't check whether unknown flags
are present[1].
This means that (generally) the addition of new flags to openat(2) has
been fraught with backwards-compatibility issues (O_TMPFILE has to be
defined as __O_TMPFILE|O_DIRECTORY|[O_RDWR or O_WRONLY] to ensure old
kernels gave errors, since it's insecure to silently ignore the
flag[2]). All new security-related flags therefore have a tough road to
being added to openat(2).
Userspace also has a hard time figuring out whether a particular flag is
supported on a particular kernel. While it is now possible with
contemporary kernels (thanks to [3]), older kernels will expose unknown
flag bits through fcntl(F_GETFL). Giving a clear -EINVAL during
openat(2) time matches modern syscall designs and is far more
fool-proof.
In addition, the newly-added path resolution restriction LOOKUP flags
(which we would like to expose to user-space) don't feel related to the
pre-existing O_* flag set -- they affect all components of path lookup.
We'd therefore like to add a new flag argument.
Adding a new syscall allows us to finally fix the flag-ignoring problem,
and we can make it extensible enough so that we will hopefully never
need an openat3(2).
/* Syscall Prototype. */
/*
* open_how is an extensible structure (similar in interface to
* clone3(2) or sched_setattr(2)). The size parameter must be set to
* sizeof(struct open_how), to allow for future extensions. All future
* extensions will be appended to open_how, with their zero value
* acting as a no-op default.
*/
struct open_how { /* ... */ };
int openat2(int dfd, const char *pathname,
struct open_how *how, size_t size);
/* Description. */
The initial version of 'struct open_how' contains the following fields:
flags
Used to specify openat(2)-style flags. However, any unknown flag
bits or otherwise incorrect flag combinations (like O_PATH|O_RDWR)
will result in -EINVAL. In addition, this field is 64-bits wide to
allow for more O_ flags than currently permitted with openat(2).
mode
The file mode for O_CREAT or O_TMPFILE.
Must be set to zero if flags does not contain O_CREAT or O_TMPFILE.
resolve
Restrict path resolution (in contrast to O_* flags they affect all
path components). The current set of flags are as follows (at the
moment, all of the RESOLVE_ flags are implemented as just passing
the corresponding LOOKUP_ flag).
RESOLVE_NO_XDEV => LOOKUP_NO_XDEV
RESOLVE_NO_SYMLINKS => LOOKUP_NO_SYMLINKS
RESOLVE_NO_MAGICLINKS => LOOKUP_NO_MAGICLINKS
RESOLVE_BENEATH => LOOKUP_BENEATH
RESOLVE_IN_ROOT => LOOKUP_IN_ROOT
open_how does not contain an embedded size field, because it is of
little benefit (userspace can figure out the kernel open_how size at
runtime fairly easily without it). It also only contains u64s (even
though ->mode arguably should be a u16) to avoid having padding fields
which are never used in the future.
Note that as a result of the new how->flags handling, O_PATH|O_TMPFILE
is no longer permitted for openat(2). As far as I can tell, this has
always been a bug and appears to not be used by userspace (and I've not
seen any problems on my machines by disallowing it). If it turns out
this breaks something, we can special-case it and only permit it for
openat(2) but not openat2(2).
After input from Florian Weimer, the new open_how and flag definitions
are inside a separate header from uapi/linux/fcntl.h, to avoid problems
that glibc has with importing that header.
/* Testing. */
In a follow-up patch there are over 200 selftests which ensure that this
syscall has the correct semantics and will correctly handle several
attack scenarios.
In addition, I've written a userspace library[4] which provides
convenient wrappers around openat2(RESOLVE_IN_ROOT) (this is necessary
because no other syscalls support RESOLVE_IN_ROOT, and thus lots of care
must be taken when using RESOLVE_IN_ROOT'd file descriptors with other
syscalls). During the development of this patch, I've run numerous
verification tests using libpathrs (showing that the API is reasonably
usable by userspace).
/* Future Work. */
Additional RESOLVE_ flags have been suggested during the review period.
These can be easily implemented separately (such as blocking auto-mount
during resolution).
Furthermore, there are some other proposed changes to the openat(2)
interface (the most obvious example is magic-link hardening[5]) which
would be a good opportunity to add a way for userspace to restrict how
O_PATH file descriptors can be re-opened.
Another possible avenue of future work would be some kind of
CHECK_FIELDS[6] flag which causes the kernel to indicate to userspace
which openat2(2) flags and fields are supported by the current kernel
(to avoid userspace having to go through several guesses to figure it
out).
[1]: https://lwn.net/Articles/588444/
[2]: https://lore.kernel.org/lkml/CA+55aFyyxJL1LyXZeBsf2ypriraj5ut1XkNDsunRBqgVjZU_6Q@mail.gmail.com
[3]: commit 629e014bb8 ("fs: completely ignore unknown open flags")
[4]: https://sourceware.org/bugzilla/show_bug.cgi?id=17523
[5]: https://lore.kernel.org/lkml/20190930183316.10190-2-cyphar@cyphar.com/
[6]: https://youtu.be/ggD-eb3yPVs
Suggested-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: Aleksa Sarai <cyphar@cyphar.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
con_init in tty/vt.c will now set conswitchp to dummy_con if it's unset.
Drop it from arch setup code.
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Link: https://lore.kernel.org/r/20191218214506.49252-20-nivedita@alum.mit.edu
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This wires up the pidfd_getfd syscall for all architectures.
Signed-off-by: Sargun Dhillon <sargun@sargun.me>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20200107175927.4558-4-sargun@sargun.me
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
The new machine loader on z15 always creates an IPL Report block and
thus sets the IPL_PL_FLAG_IPLSR even when secure boot is disabled. This
causes the wrong message being printed at boot. Fix this by checking for
IPL_PL_FLAG_SIPL instead.
Fixes: 9641b8cc73 ("s390/ipl: read IPL report at early boot")
Signed-off-by: Philipp Rudo <prudo@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
