In __apic_accept_irq() interface trig_mode is int and actually on some code
paths it is set above u8:

kvm_apic_set_irq() extracts it from 'struct kvm_lapic_irq' where trig_mode
is u16. This is done on purpose as e.g. kvm_set_msi_irq() sets it to
(1 << 15) & e->msi.data

kvm_apic_local_deliver sets it to reg & (1 << 15).

Fix the immediate issue by making 'tm' into u16. We may also want to adjust
__apic_accept_irq() interface and use proper sizes for vector, level,
trig_mode but this is not urgent.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

These were found with smatch, and then generalized when applicable.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Changed passing argument as "0 to NULL" which resolves below sparse warning

arch/x86/kvm/x86.c:3096:61: warning: Using plain integer as NULL pointer
Signed-off-by: Hariprasad Kelam <hariprasad.kelam@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Add a simple test for SMM, based on VMX.  The test implements its own
sync between the guest and the host as using our ucall library seems to
be too cumbersome: SMI handler is happening in real-address mode.

This patch also fixes KVM_SET_NESTED_STATE to happen after
KVM_SET_VCPU_EVENTS, in fact it places it last.  This is because
KVM needs to know whether the processor is in SMM or not.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

-no-pie was added to GCC at the same time as their configuration option
--enable-default-pie.  Compilers that were built before do not have
-no-pie, but they also do not need it.  Detect the option at build
time.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Starting state migration after an IO exit without first completing IO
may result in test failures.  We already have two tests that need this
(this patch in fact fixes evmcs_test, similar to what was fixed for
state_test in commit 0f73bbc8, "KVM: selftests: complete IO before
migrating guest state", 2019-03-13) and a third is coming.  So, move the
code to vcpu_save_state, and while at it do not access register state
until after I/O is complete.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Invoking the 64-bit variation on a 32-bit kenrel will crash the guest,
trigger a WARN, and/or lead to a buffer overrun in the host, e.g.
rsm_load_state_64() writes r8-r15 unconditionally, but enum kvm_reg and
thus x86_emulate_ctxt._regs only define r8-r15 for CONFIG_X86_64.

KVM allows userspace to report long mode support via CPUID, even though
the guest is all but guaranteed to crash if it actually tries to enable
long mode.  But, a pure 32-bit guest that is ignorant of long mode will
happily plod along.

SMM complicates things as 64-bit CPUs use a different SMRAM save state
area.  KVM handles this correctly for 64-bit kernels, e.g. uses the
legacy save state map if userspace has hid long mode from the guest,
but doesn't fare well when userspace reports long mode support on a
32-bit host kernel (32-bit KVM doesn't support 64-bit guests).

Since the alternative is to crash the guest, e.g. by not loading state
or explicitly requesting shutdown, unconditionally use the legacy SMRAM
save state map for 32-bit KVM.  If a guest has managed to get far enough
to handle SMIs when running under a weird/buggy userspace hypervisor,
then don't deliberately crash the guest since there are no downsides
(from KVM's perspective) to allow it to continue running.

Fixes: 660a5d51 ("KVM: x86: save/load state on SMM switch")
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Neither AMD nor Intel CPUs have an EFER field in the legacy SMRAM save
state area, i.e. don't save/restore EFER across SMM transitions.  KVM
somewhat models this, e.g. doesn't clear EFER on entry to SMM if the
guest doesn't support long mode.  But during RSM, KVM unconditionally
clears EFER so that it can get back to pure 32-bit mode in order to
start loading CRs with their actual non-SMM values.

Clear EFER only when it will be written when loading the non-SMM state
so as to preserve bits that can theoretically be set on 32-bit vCPUs,
e.g. KVM always emulates EFER_SCE.

And because CR4.PAE is cleared only to play nice with EFER, wrap that
code in the long mode check as well.  Note, this may result in a
compiler warning about cr4 being consumed uninitialized.  Re-read CR4
even though it's technically unnecessary, as doing so allows for more
readable code and RSM emulation is not a performance critical path.

Fixes: 660a5d51 ("KVM: x86: save/load state on SMM switch")
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

RSM emulation is currently broken on VMX when the interrupted guest has
CR4.VMXE=1.  Stop dancing around the issue of HF_SMM_MASK being set when
loading SMSTATE into architectural state, e.g. by toggling it for
problematic flows, and simply clear HF_SMM_MASK prior to loading
architectural state (from SMRAM save state area).
Reported-by: Jon Doron <arilou@gmail.com>
Cc: Jim Mattson <jmattson@google.com>
Cc: Liran Alon <liran.alon@oracle.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Fixes: 5bea5123 ("KVM: VMX: check nested state and CR4.VMXE against SMM")
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Tested-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Prepare for clearing HF_SMM_MASK prior to loading state from the SMRAM
save state map, i.e. kvm_smm_changed() needs to be called after state
has been loaded and so cannot be done automatically when setting
hflags from RSM.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

RSM emulation is currently broken on VMX when the interrupted guest has
CR4.VMXE=1.  Rather than dance around the issue of HF_SMM_MASK being set
when loading SMSTATE into architectural state, ideally RSM emulation
itself would be reworked to clear HF_SMM_MASK prior to loading non-SMM
architectural state.

Ostensibly, the only motivation for having HF_SMM_MASK set throughout
the loading of state from the SMRAM save state area is so that the
memory accesses from GET_SMSTATE() are tagged with role.smm.  Load
all of the SMRAM save state area from guest memory at the beginning of
RSM emulation, and load state from the buffer instead of reading guest
memory one-by-one.

This paves the way for clearing HF_SMM_MASK prior to loading state,
and also aligns RSM with the enter_smm() behavior, which fills a
buffer and writes SMRAM save state in a single go.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Issue was discovered when running kvm-unit-tests on KVM running as L1 on
top of Hyper-V.

When vmx_instruction_intercept unit-test attempts to run RDPMC to test
RDPMC-exiting, it is intercepted by L1 KVM which it's EXIT_REASON_RDPMC
handler raise #GP because vCPU exposed by Hyper-V doesn't support PMU.
Instead of unit-test expectation to be reflected with EXIT_REASON_RDPMC.

The reason vmx_instruction_intercept unit-test attempts to run RDPMC
even though Hyper-V doesn't support PMU is because L1 expose to L2
support for RDPMC-exiting. Which is reasonable to assume that is
supported only in case CPU supports PMU to being with.

Above issue can easily be simulated by modifying
vmx_instruction_intercept config in x86/unittests.cfg to run QEMU with
"-cpu host,+vmx,-pmu" and run unit-test.

To handle issue, change KVM to expose RDPMC-exiting only when guest
supports PMU.
Reported-by: Saar Amar <saaramar@microsoft.com>
Reviewed-by: Mihai Carabas <mihai.carabas@oracle.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Before this change, reading a VMware pseduo PMC will succeed even when
PMU is not supported by guest. This can easily be seen by running
kvm-unit-test vmware_backdoors with "-cpu host,-pmu" option.
Reviewed-by: Mihai Carabas <mihai.carabas@oracle.com>
Signed-off-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

guest xcr0 could leak into host when MCE happens in guest mode. Because
do_machine_check() could schedule out at a few places.

For example:

kvm_load_guest_xcr0
...
kvm_x86_ops->run(vcpu) {
  vmx_vcpu_run
    vmx_complete_atomic_exit
      kvm_machine_check
        do_machine_check
          do_memory_failure
            memory_failure
              lock_page

In this case, host_xcr0 is 0x2ff, guest vcpu xcr0 is 0xff. After schedule
out, host cpu has guest xcr0 loaded (0xff).

In __switch_to {
     switch_fpu_finish
       copy_kernel_to_fpregs
         XRSTORS

If any bit i in XSTATE_BV[i] == 1 and xcr0[i] == 0, XRSTORS will
generate #GP (In this case, bit 9). Then ex_handler_fprestore kicks in
and tries to reinitialize fpu by restoring init fpu state. Same story as
last #GP, except we get DOUBLE FAULT this time.

Cc: stable@vger.kernel.org
Signed-off-by: WANG Chao <chao.wang@ucloud.cn>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

I noticed that apic test from kvm-unit-tests always hangs on my EPYC 7401P,
the hanging test nmi-after-sti is trying to deliver 30000 NMIs and tracing
shows that we're sometimes able to deliver a few but never all.

When we're trying to inject an NMI we may fail to do so immediately for
various reasons, however, we still need to inject it so enable_nmi_window()
arms nmi_singlestep mode. #DB occurs as expected, but we're not checking
for pending NMIs before entering the guest and unless there's a different
event to process, the NMI will never get delivered.

Make KVM_REQ_EVENT request on the vCPU from db_interception() to make sure
pending NMIs are checked and possibly injected.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Only clear the valid bit when invalidate logical APIC id entry.
The current logic clear the valid bit, but also set the rest of
the bits (including reserved bits) to 1.

Fixes: 98d90582 ('svm: Fix AVIC DFR and LDR handling')
Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

This reverts commit bb218fbc.

As Oren Twaig pointed out the old discussion:

  https://patchwork.kernel.org/patch/8292231/

that the change coud potentially cause an extra IPI to be sent to
the destination vcpu because the AVIC hardware already set the IRR bit
before the incomplete IPI #VMEXIT with id=1 (target vcpu is not running).
Since writting to ICR and ICR2 will also set the IRR. If something triggers
the destination vcpu to get scheduled before the emulation finishes, then
this could result in an additional IPI.

Also, the issue mentioned in the commit bb218fbc was misdiagnosed.

Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Reported-by: Oren Twaig <oren@scalemp.com>
Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

KVM bases its memory usage limits on the total number of guest pages
across all memslots. However, those limits, and the calculations to
produce them, use 32 bit unsigned integers. This can result in overflow
if a VM has more guest pages that can be represented by a u32. As a
result of this overflow, KVM can use a low limit on the number of MMU
pages it will allocate. This makes KVM unable to map all of guest memory
at once, prompting spurious faults.

Tested: Ran all kvm-unit-tests on an Intel Haswell machine. This patch
	introduced no new failures.
Signed-off-by: Ben Gardon <bgardon@google.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

The remaining failures of vmx.flat when EPT is disabled are caused by
incorrectly reflecting VMfails to the L1 hypervisor.  What happens is
that nested_vmx_restore_host_state corrupts the guest CR3, reloading it
with the host's shadow CR3 instead, because it blindly loads GUEST_CR3
from the vmcs01.

For simplicity let's just always use hardware VMCS checks when EPT is
disabled.  This way, nested_vmx_restore_host_state is not reached at
all (or at least shouldn't be reached).
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

As mentioned in the comment, there are some special cases where we can simply
clear the TPR shadow bit from the CPU-based execution controls in the vmcs02.
Handle them so that we can remove some XFAILs from vmx.flat.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

A recently introduced helper for handling zap vs. remote flush
incorrectly bails early, effectively leaking defunct shadow pages.
Manifests as a slab BUG when exiting KVM due to the shadow pages
being alive when their associated cache is destroyed.

==========================================================================
BUG kvm_mmu_page_header: Objects remaining in kvm_mmu_page_header on ...
--------------------------------------------------------------------------
Disabling lock debugging due to kernel taint
INFO: Slab 0x00000000fc436387 objects=26 used=23 fp=0x00000000d023caee ...
CPU: 6 PID: 4315 Comm: rmmod Tainted: G    B             5.1.0-rc2+ #19
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
Call Trace:
 dump_stack+0x46/0x5b
 slab_err+0xad/0xd0
 ? on_each_cpu_mask+0x3c/0x50
 ? ksm_migrate_page+0x60/0x60
 ? on_each_cpu_cond_mask+0x7c/0xa0
 ? __kmalloc+0x1ca/0x1e0
 __kmem_cache_shutdown+0x13a/0x310
 shutdown_cache+0xf/0x130
 kmem_cache_destroy+0x1d5/0x200
 kvm_mmu_module_exit+0xa/0x30 [kvm]
 kvm_arch_exit+0x45/0x60 [kvm]
 kvm_exit+0x6f/0x80 [kvm]
 vmx_exit+0x1a/0x50 [kvm_intel]
 __x64_sys_delete_module+0x153/0x1f0
 ? exit_to_usermode_loop+0x88/0xc0
 do_syscall_64+0x4f/0x100
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Fixes: a2113634 ("KVM: x86/mmu: Split remote_flush+zap case out of kvm_mmu_flush_or_zap()")
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Badly-designed systems might have (for example) active-high wake pins
that default to high (e.g., because of external pull ups) until they
have an active firmware which starts driving it low.  This can cause an
interrupt storm in the time between request_irq() and disable_irq().

We don't support shared interrupts here, so let's just pre-configure the
interrupt to avoid auto-enabling it.

Fixes: fd913ef7 ("Bluetooth: btusb: Add out-of-band wakeup support")
Fixes: 5364a0b4 ("arm64: dts: rockchip: move QCA6174A wakeup pin into its USB node")
Signed-off-by: Brian Norris <briannorris@chromium.org>
Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull MIPS fixes from Paul Burton:
 "A few minor MIPS fixes:

   - Provide struct pt_regs * from get_irq_regs() to kgdb_nmicallback()
     when handling an IPI triggered by kgdb_roundup_cpus(), matching the
     behavior of other architectures & resolving kgdb issues for SMP
     systems.

   - Defer a pointer dereference until after a NULL check in the
     irq_shutdown callback for SGI IP27 HUB interrupts.

   - A defconfig update for the MSCC Ocelot to enable some necessary
     drivers"

* tag 'mips_fixes_5.1_2' of git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux:
  MIPS: generic: Add switchdev, pinctrl and fit to ocelot_defconfig
  MIPS: SGI-IP27: Fix use of unchecked pointer in shutdown_bridge_irq
  MIPS: KGDB: fix kgdb support for SMP platforms.

Pull misc fixes from Al Viro:
 "A few regression fixes from this cycle"

* 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  aio: use kmem_cache_free() instead of kfree()
  iov_iter: Fix build error without CONFIG_CRYPTO
  aio: Fix an error code in __io_submit_one()

Pull networking fixes from David Miller:

 1) Off by one and bounds checking fixes in NFC, from Dan Carpenter.

 2) There have been many weird regressions in r8169 since we turned ASPM
    support on, some are still not understood nor completely resolved.
    Let's turn this back off for now. From Heiner Kallweit.

 3) Signess fixes for ethtool speed value handling, from Michael
    Zhivich.

 4) Handle timestamps properly in macb driver, from Paul Thomas.

 5) Two erspan fixes, it's the usual "skb ->data potentially reallocated
    and we're holding a stale protocol header pointer". From Lorenzo
    Bianconi.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net:
  bnxt_en: Reset device on RX buffer errors.
  bnxt_en: Improve RX consumer index validity check.
  net: macb driver, check for SKBTX_HW_TSTAMP
  qlogic: qlcnic: fix use of SPEED_UNKNOWN ethtool constant
  broadcom: tg3: fix use of SPEED_UNKNOWN ethtool constant
  ethtool: avoid signed-unsigned comparison in ethtool_validate_speed()
  net: ip6_gre: fix possible use-after-free in ip6erspan_rcv
  net: ip_gre: fix possible use-after-free in erspan_rcv
  r8169: disable ASPM again
  MAINTAINERS: ieee802154: update documentation file pattern
  net: vrf: Fix ping failed when vrf mtu is set to 0
  selftests: add a tc matchall test case
  nfc: nci: Potential off by one in ->pipes[] array
  NFC: nci: Add some bounds checking in nci_hci_cmd_received()

Pull TPM fixes from James Morris:
 "From Jarkko: These are critical fixes for v5.1. Contains also couple
  of new selftests for v5.1 features (partial reads in /dev/tpm0)"

* 'fixes-v5.1' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security:
  selftests/tpm2: Open tpm dev in unbuffered mode
  selftests/tpm2: Extend tests to cover partial reads
  KEYS: trusted: fix -Wvarags warning
  tpm: Fix the type of the return value in calc_tpm2_event_size()
  KEYS: trusted: allow trusted.ko to initialize w/o a TPM
  tpm: fix an invalid condition in tpm_common_poll
  tpm: turn on TPM on suspend for TPM 1.x

Pull xtensa fixes from Max Filippov:

 - fix syscall number passed to trace_sys_exit

 - fix syscall number initialization in start_thread

 - fix level interpretation in the return_address

 - fix format string warning in init_pmd

* tag 'xtensa-20190408' of git://github.com/jcmvbkbc/linux-xtensa:
  xtensa: fix format string warning in init_pmd
  xtensa: fix return_address
  xtensa: fix initialization of pt_regs::syscall in start_thread
  xtensa: use actual syscall number in do_syscall_trace_leave

Michael Chan says:

====================
bnxt_en: 2 bug fixes.

The first patch prevents possible driver crash if we get a bad RX index
from the hardware.  The second patch resets the device when the hardware
reports buffer error to recover from the error.

Please queue these for -stable also.  Thanks.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

If the RX completion indicates RX buffers errors, the RX ring will be
disabled by firmware and no packets will be received on that ring from
that point on.  Recover by resetting the device.

Fixes: c0c050c5 ("bnxt_en: New Broadcom ethernet driver.")
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

There is logic to check that the RX/TPA consumer index is the expected
index to work around a hardware problem.  However, the potentially bad
consumer index is first used to index into an array to reference an entry.
This can potentially crash if the bad consumer index is beyond legal
range.  Improve the logic to use the consumer index for dereferencing
after the validity check and log an error message.

Fixes: fa7e2812 ("bnxt_en: Add workaround to detect bad opaque in rx completion (part 2)")
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Make sure SKBTX_HW_TSTAMP (i.e. SOF_TIMESTAMPING_TX_HARDWARE) has been
enabled for this skb. It does fix the issue where normal socks that
aren't expecting a timestamp will not wake up on select, but when a
user does want a SOF_TIMESTAMPING_TX_HARDWARE it does work.
Signed-off-by: Paul Thomas <pthomas8589@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Michael Zhivich says:

====================
ethtool: fix use of SPEED_UNKNOWN constant

This patch series addresses 2 related issues:

1. ethtool_validate_speed() triggers a "signed-unsigned comparison"
warning due to type difference of SPEED_UNKNOWN constant (int)
and argument to ethtool_validate_speed (__u32).

2. some drivers use u16 storage for SPEED_UNKNOWN constant,
resulting in value truncation and thus failure to test against
SPEED_UNKNOWN correctly.

This revised series addresses several feedback comments:
- split up the patch in to series
- do not unnecessarily change drivers that use "int" storage
  for speed values
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

qlcnic driver uses u16 to store SPEED_UKNOWN ethtool constant,
which is defined as -1, resulting in value truncation and
thus incorrect test results against SPEED_UNKNOWN.

For example, the following test will print "False":

    u16 speed = SPEED_UNKNOWN;

    if (speed == SPEED_UNKNOWN)
        printf("True");
    else
        printf("False");

Change storage of speed to use u32 to avoid this issue.
Signed-off-by: Michael Zhivich <mzhivich@akamai.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

tg3 driver uses u16 to store SPEED_UKNOWN ethtool constant,
which is defined as -1, resulting in value truncation and
thus incorrect test results against SPEED_UNKNOWN.

For example, the following test will print "False":

	u16 speed = SPEED_UNKNOWN;

	if (speed == SPEED_UNKNOWN)
	    printf("True");
	else
	    printf("False");

Change storage of speed to use u32 to avoid this issue.
Signed-off-by: Michael Zhivich <mzhivich@akamai.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

When building C++ userspace code that includes ethtool.h
with "-Werror -Wall", g++ complains about signed-unsigned comparison in
ethtool_validate_speed() due to definition of SPEED_UNKNOWN as -1.

Explicitly cast SPEED_UNKNOWN to __u32 to match type of
ethtool_validate_speed() argument.
Signed-off-by: Michael Zhivich <mzhivich@akamai.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Lorenzo Bianconi says:

====================
fix possible use-after-free in erspan_v{4,6}

Similar to what I did in commit bb9bd814 ("ipv6: sit: reset ip
header pointer in ipip6_rcv"), fix possible use-after-free in
erspan_rcv and ip6erspan_rcv extracting tunnel metadata since the
packet can be 'uncloned' running __iptunnel_pull_header
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

erspan_v6 tunnels run __iptunnel_pull_header on received skbs to remove
erspan header. This can determine a possible use-after-free accessing
pkt_md pointer in ip6erspan_rcv since the packet will be 'uncloned'
running pskb_expand_head if it is a cloned gso skb (e.g if the packet has
been sent though a veth device). Fix it resetting pkt_md pointer after
__iptunnel_pull_header

Fixes: 1d7e2ed2 ("net: erspan: refactor existing erspan code")
Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

erspan tunnels run __iptunnel_pull_header on received skbs to remove
gre and erspan headers. This can determine a possible use-after-free
accessing pkt_md pointer in erspan_rcv since the packet will be 'uncloned'
running pskb_expand_head if it is a cloned gso skb (e.g if the packet has
been sent though a veth device). Fix it resetting pkt_md pointer after
__iptunnel_pull_header

Fixes: 1d7e2ed2 ("net: erspan: refactor existing erspan code")
Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

In order to have control over how many bytes are read or written
the device needs to be opened in unbuffered mode.
Signed-off-by: Tadeusz Struk <tadeusz.struk@intel.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Tested-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: James Morris <james.morris@microsoft.com>

Three new tests added:
1. Send get random cmd, read header in 1st read, read the rest in second
   read - expect success
2. Send get random cmd, read only part of the response, send another
   get random command, read the response - expect success
3. Send get random cmd followed by another get random cmd, without
   reading the first response - expect the second cmd to fail with -EBUSY
Signed-off-by: Tadeusz Struk <tadeusz.struk@intel.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Tested-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: James Morris <james.morris@microsoft.com>