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  1. Dec 26, 2021
  3. Dec 23, 2021
  5. Dec 22, 2021
  7. Dec 21, 2021
    • Wu Bo's avatar
      ipmi: Fix UAF when uninstall ipmi_si and ipmi_msghandler module · ffb76a86
      Wu Bo authored 
      Hi,

When testing install and uninstall of ipmi_si.ko and ipmi_msghandler.ko,
the system crashed.

The log as follows:
[  141.087026] BUG: unable to handle kernel paging request at ffffffffc09b3a5a
[  141.087241] PGD 8fe4c0d067 P4D 8fe4c0d067 PUD 8fe4c0f067 PMD 103ad89067 PTE 0
[  141.087464] Oops: 0010 [#1] SMP NOPTI
[  141.087580] CPU: 67 PID: 668 Comm: kworker/67:1 Kdump: loaded Not tainted 4.18.0.x86_64 #47
[  141.088009] Workqueue: events 0xffffffffc09b3a40
[  141.088009] RIP: 0010:0xffffffffc09b3a5a
[  141.088009] Code: Bad RIP value.
[  141.088009] RSP: 0018:ffffb9094e2c3e88 EFLAGS: 00010246
[  141.088009] RAX: 0000000000000000 RBX: ffff9abfdb1f04a0 RCX: 0000000000000000
[  141.088009] RDX: 0000000000000000 RSI: 0000000000000246 RDI: 0000000000000246
[  141.088009] RBP: 0000000000000000 R08: ffff9abfffee3cb8 R09: 00000000000002e1
[  141.088009] R10: ffffb9094cb73d90 R11: 00000000000f4240 R12: ffff9abfffee8700
[  141.088009] R13: 0000000000000000 R14: ffff9abfdb1f04a0 R15: ffff9abfdb1f04a8
[  141.088009] FS:  0000000000000000(0000) GS:ffff9abfffec0000(0000) knlGS:0000000000000000
[  141.088009] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  141.088009] CR2: ffffffffc09b3a30 CR3: 0000008fe4c0a001 CR4: 00000000007606e0
[  141.088009] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  141.088009] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[  141.088009] PKRU: 55555554
[  141.088009] Call Trace:
[  141.088009]  ? process_one_work+0x195/0x390
[  141.088009]  ? worker_thread+0x30/0x390
[  141.088009]  ? process_one_work+0x390/0x390
[  141.088009]  ? kthread+0x10d/0x130
[  141.088009]  ? kthread_flush_work_fn+0x10/0x10
[  141.088009]  ? ret_from_fork+0x35/0x40] BUG: unable to handle kernel paging request at ffffffffc0b28a5a
[  200.223240] PGD 97fe00d067 P4D 97fe00d067 PUD 97fe00f067 PMD a580cbf067 PTE 0
[  200.223464] Oops: 0010 [#1] SMP NOPTI
[  200.223579] CPU: 63 PID: 664 Comm: kworker/63:1 Kdump: loaded Not tainted 4.18.0.x86_64 #46
[  200.224008] Workqueue: events 0xffffffffc0b28a40
[  200.224008] RIP: 0010:0xffffffffc0b28a5a
[  200.224008] Code: Bad RIP value.
[  200.224008] RSP: 0018:ffffbf3c8e2a3e88 EFLAGS: 00010246
[  200.224008] RAX: 0000000000000000 RBX: ffffa0799ad6bca0 RCX: 0000000000000000
[  200.224008] RDX: 0000000000000000 RSI: 0000000000000246 RDI: 0000000000000246
[  200.224008] RBP: 0000000000000000 R08: ffff9fe43fde3cb8 R09: 00000000000000d5
[  200.224008] R10: ffffbf3c8cb53d90 R11: 00000000000f4240 R12: ffff9fe43fde8700
[  200.224008] R13: 0000000000000000 R14: ffffa0799ad6bca0 R15: ffffa0799ad6bca8
[  200.224008] FS:  0000000000000000(0000) GS:ffff9fe43fdc0000(0000) knlGS:0000000000000000
[  200.224008] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  200.224008] CR2: ffffffffc0b28a30 CR3: 00000097fe00a002 CR4: 00000000007606e0
[  200.224008] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  200.224008] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[  200.224008] PKRU: 55555554
[  200.224008] Call Trace:
[  200.224008]  ? process_one_work+0x195/0x390
[  200.224008]  ? worker_thread+0x30/0x390
[  200.224008]  ? process_one_work+0x390/0x390
[  200.224008]  ? kthread+0x10d/0x130
[  200.224008]  ? kthread_flush_work_fn+0x10/0x10
[  200.224008]  ? ret_from_fork+0x35/0x40
[  200.224008] kernel fault(0x1) notification starting on CPU 63
[  200.224008] kernel fault(0x1) notification finished on CPU 63
[  200.224008] CR2: ffffffffc0b28a5a
[  200.224008] ---[ end trace c82a412d93f57412 ]---

The reason is as follows:
T1: rmmod ipmi_si.
    ->ipmi_unregister_smi()
        -> ipmi_bmc_unregister()
            -> __ipmi_bmc_unregister()
                -> kref_put(&bmc->usecount, cleanup_bmc_device);
                    -> schedule_work(&bmc->remove_work);

T2: rmmod ipmi_msghandler.
    ipmi_msghander module uninstalled, and the module space
    will be freed.

T3: bmc->remove_work doing cleanup the bmc resource.
    -> cleanup_bmc_work()
        -> platform_device_unregister(&bmc->pdev);
            -> platform_device_del(pdev);
                -> device_del(&pdev->dev);
                    -> kobject_uevent(&dev->kobj, KOBJ_REMOVE);
                        -> kobject_uevent_env()
                            -> dev_uevent()
                                -> if (dev->type && dev->type->name)

   'dev->type'(bmc_device_type) pointer space has freed when uninstall
    ipmi_msghander module, 'dev->type->name' cause the system crash.

drivers/char/ipmi/ipmi_msghandler.c:
2820 static const struct device_type bmc_device_type = {
2821         .groups         = bmc_dev_attr_groups,
2822 };

Steps to reproduce:
Add a time delay in cleanup_bmc_work() function,
and uninstall ipmi_si and ipmi_msghandler module.

2910 static void cleanup_bmc_work(struct work_struct *work)
2911 {
2912         struct bmc_device *bmc = container_of(work, struct bmc_device,
2913                                               remove_work);
2914         int id = bmc->pdev.id; /* Unregister overwrites id */
2915
2916         msleep(3000);   <---
2917         platform_device_unregister(&bmc->pdev);
2918         ida_simple_remove(&ipmi_bmc_ida, id);
2919 }

Use 'remove_work_wq' instead of 'system_wq' to solve this issues.

Fixes: b2cfd8ab

 ("ipmi: Rework device id and guid handling to catch changing BMCs")
Signed-off-by: default avatarWu Bo <wubo40@huawei.com>
Message-Id: <1640070034-56671-1-git-send-email-wubo40@huawei.com>
Signed-off-by: default avatarCorey Minyard <cminyard@mvista.com>
      ffb76a86
    • Linus Torvalds's avatar
      Merge tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma · 6e0567b7
      Linus Torvalds authored 
      Pull rdma fixes from Jason Gunthorpe:
 "Last fixes before holidays. Nothing very exciting:

   - Work around a HW bug in HNS HIP08

   - Recent memory leak regression in qib

   - Incorrect use of kfree() for vmalloc memory in hns"

* tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma:
  RDMA/hns: Replace kfree() with kvfree()
  IB/qib: Fix memory leak in qib_user_sdma_queue_pkts()
  RDMA/hns: Fix RNR retransmission issue for HIP08
      6e0567b7
    • Linus Torvalds's avatar
      Merge tag 'spi-fix-v5.16-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi · 86085fe7
      Linus Torvalds authored 
      Pull spi fix from Mark Brown:
 "One small fix for a long standing issue with error handling on probe
  in the Armada driver"

* tag 'spi-fix-v5.16-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi:
  spi: change clk_disable_unprepare to clk_unprepare
      86085fe7
    • Linus Torvalds's avatar
      Merge tag 'regulator-fix-v5.16-rc6' of... · 3856c1b3
      Linus Torvalds authored 
      Merge tag 'regulator-fix-v5.16-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regulator

Pull regulator fix from Mark Brown:
 "Binding fix for v5.16

  This fixes problems validating DT bindings using op_mode which wasn't
  described as it should have been when converting to DT schema"

* tag 'regulator-fix-v5.16-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regulator:
  regulator: dt-bindings: samsung,s5m8767: add missing op_mode to bucks
      3856c1b3
  9. Dec 20, 2021
    • Linus Torvalds's avatar
      Merge branch 'xsa' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip · 59b3f944
      Linus Torvalds authored 
      Merge xen fixes from Juergen Gross:
 "Fixes for two issues related to Xen and malicious guests:

   - Guest can force the netback driver to hog large amounts of memory

   - Denial of Service in other guests due to event storms"

* 'xsa' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  xen/netback: don't queue unlimited number of packages
  xen/netback: fix rx queue stall detection
  xen/console: harden hvc_xen against event channel storms
  xen/netfront: harden netfront against event channel storms
  xen/blkfront: harden blkfront against event channel storms
      59b3f944
    • Helge Deller's avatar
      parisc: Clear stale IIR value on instruction access rights trap · 484730e5
      Helge Deller authored 
      

When a trap 7 (Instruction access rights) occurs, this means the CPU
couldn't execute an instruction due to missing execute permissions on
the memory region.  In this case it seems the CPU didn't even fetched
the instruction from memory and thus did not store it in the cr19 (IIR)
register before calling the trap handler. So, the trap handler will find
some random old stale value in cr19.

This patch simply overwrites the stale IIR value with a constant magic
"bad food" value (0xbaadf00d), in the hope people don't start to try to
understand the various random IIR values in trap 7 dumps.

Noticed-by: default avatarJohn David Anglin <dave.anglin@bell.net>
Signed-off-by: default avatarHelge Deller <deller@gmx.de>
      484730e5
    • Sean Christopherson's avatar
      KVM: selftests: Add test to verify TRIPLE_FAULT on invalid L2 guest state · ab1ef344
      Sean Christopherson authored 
      Add a selftest to attempt to enter L2 with invalid guests state by
exiting to userspace via I/O from L2, and then using KVM_SET_SREGS to set
invalid guest state (marking TR unusable is arbitrary chosen for its
relative simplicity).

This is a regression test for a bug introduced by commit c8607e4a


("KVM: x86: nVMX: don't fail nested VM entry on invalid guest state if
!from_vmentry"), which incorrectly set vmx->fail=true when L2 had invalid
guest state and ultimately triggered a WARN due to nested_vmx_vmexit()
seeing vmx->fail==true while attempting to synthesize a nested VM-Exit.

The is also a functional test to verify that KVM sythesizes TRIPLE_FAULT
for L2, which is somewhat arbitrary behavior, instead of emulating L2.
KVM should never emulate L2 due to invalid guest state, as it's
architecturally impossible for L1 to run an L2 guest with invalid state
as nested VM-Enter should always fail, i.e. L1 needs to do the emulation.
Stuffing state via KVM ioctl() is a non-architctural, out-of-band case,
hence the TRIPLE_FAULT being rather arbitrary.

Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
Message-Id: <20211207193006.120997-5-seanjc@google.com>
Reviewed-by: default avatarMaxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      ab1ef344
    • Sean Christopherson's avatar
      KVM: VMX: Fix stale docs for kvm-intel.emulate_invalid_guest_state · 0ff29701
      Sean Christopherson authored 
      Update the documentation for kvm-intel's emulate_invalid_guest_state to
rectify the description of KVM's default behavior, and to document that
the behavior and thus parameter only applies to L1.

Fixes: a27685c3

 ("KVM: VMX: Emulate invalid guest state by default")
Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
Message-Id: <20211207193006.120997-4-seanjc@google.com>
Reviewed-by: default avatarMaxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      0ff29701
    • Sean Christopherson's avatar
      KVM: nVMX: Synthesize TRIPLE_FAULT for L2 if emulation is required · cd0e615c
      Sean Christopherson authored 
      

Synthesize a triple fault if L2 guest state is invalid at the time of
VM-Enter, which can happen if L1 modifies SMRAM or if userspace stuffs
guest state via ioctls(), e.g. KVM_SET_SREGS.  KVM should never emulate
invalid guest state, since from L1's perspective, it's architecturally
impossible for L2 to have invalid state while L2 is running in hardware.
E.g. attempts to set CR0 or CR4 to unsupported values will either VM-Exit
or #GP.

Modifying vCPU state via RSM+SMRAM and ioctl() are the only paths that
can trigger this scenario, as nested VM-Enter correctly rejects any
attempt to enter L2 with invalid state.

RSM is a straightforward case as (a) KVM follows AMD's SMRAM layout and
behavior, and (b) Intel's SDM states that loading reserved CR0/CR4 bits
via RSM results in shutdown, i.e. there is precedent for KVM's behavior.
Following AMD's SMRAM layout is important as AMD's layout saves/restores
the descriptor cache information, including CS.RPL and SS.RPL, and also
defines all the fields relevant to invalid guest state as read-only, i.e.
so long as the vCPU had valid state before the SMI, which is guaranteed
for L2, RSM will generate valid state unless SMRAM was modified.  Intel's
layout saves/restores only the selector, which means that scenarios where
the selector and cached RPL don't match, e.g. conforming code segments,
would yield invalid guest state.  Intel CPUs fudge around this issued by
stuffing SS.RPL and CS.RPL on RSM.  Per Intel's SDM on the "Default
Treatment of RSM", paraphrasing for brevity:

  IF internal storage indicates that the [CPU was post-VMXON]
  THEN
     enter VMX operation (root or non-root);
     restore VMX-critical state as defined in Section 34.14.1;
     set to their fixed values any bits in CR0 and CR4 whose values must
     be fixed in VMX operation [unless coming from an unrestricted guest];
     IF RFLAGS.VM = 0 AND (in VMX root operation OR the
        “unrestricted guest” VM-execution control is 0)
     THEN
       CS.RPL := SS.DPL;
       SS.RPL := SS.DPL;
     FI;
     restore current VMCS pointer;
  FI;

Note that Intel CPUs also overwrite the fixed CR0/CR4 bits, whereas KVM
will sythesize TRIPLE_FAULT in this scenario.  KVM's behavior is allowed
as both Intel and AMD define CR0/CR4 SMRAM fields as read-only, i.e. the
only way for CR0 and/or CR4 to have illegal values is if they were
modified by the L1 SMM handler, and Intel's SDM "SMRAM State Save Map"
section states "modifying these registers will result in unpredictable
behavior".

KVM's ioctl() behavior is less straightforward.  Because KVM allows
ioctls() to be executed in any order, rejecting an ioctl() if it would
result in invalid L2 guest state is not an option as KVM cannot know if
a future ioctl() would resolve the invalid state, e.g. KVM_SET_SREGS, or
drop the vCPU out of L2, e.g. KVM_SET_NESTED_STATE.  Ideally, KVM would
reject KVM_RUN if L2 contained invalid guest state, but that carries the
risk of a false positive, e.g. if RSM loaded invalid guest state and KVM
exited to userspace.  Setting a flag/request to detect such a scenario is
undesirable because (a) it's extremely unlikely to add value to KVM as a
whole, and (b) KVM would need to consider ioctl() interactions with such
a flag, e.g. if userspace migrated the vCPU while the flag were set.

Cc: stable@vger.kernel.org
Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
Message-Id: <20211207193006.120997-3-seanjc@google.com>
Reviewed-by: default avatarMaxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      cd0e615c
    • Sean Christopherson's avatar
      KVM: VMX: Always clear vmx->fail on emulation_required · a80dfc02
      Sean Christopherson authored 
      Revert a relatively recent change that set vmx->fail if the vCPU is in L2
and emulation_required is true, as that behavior is completely bogus.
Setting vmx->fail and synthesizing a VM-Exit is contradictory and wrong:

  (a) it's impossible to have both a VM-Fail and VM-Exit
  (b) vmcs.EXIT_REASON is not modified on VM-Fail
  (c) emulation_required refers to guest state and guest state checks are
      always VM-Exits, not VM-Fails.

For KVM specifically, emulation_required is handled before nested exits
in __vmx_handle_exit(), thus setting vmx->fail has no immediate effect,
i.e. KVM calls into handle_invalid_guest_state() and vmx->fail is ignored.
Setting vmx->fail can ultimately result in a WARN in nested_vmx_vmexit()
firing when tearing down the VM as KVM never expects vmx->fail to be set
when L2 is active, KVM always reflects those errors into L1.

  ------------[ cut here ]------------
  WARNING: CPU: 0 PID: 21158 at arch/x86/kvm/vmx/nested.c:4548
                                nested_vmx_vmexit+0x16bd/0x17e0
                                arch/x86/kvm/vmx/nested.c:4547
  Modules linked in:
  CPU: 0 PID: 21158 Comm: syz-executor.1 Not tainted 5.16.0-rc3-syzkaller #0
  Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
  RIP: 0010:nested_vmx_vmexit+0x16bd/0x17e0 arch/x86/kvm/vmx/nested.c:4547
  Code: <0f> 0b e9 2e f8 ff ff e8 57 b3 5d 00 0f 0b e9 00 f1 ff ff 89 e9 80
  Call Trace:
   vmx_leave_nested arch/x86/kvm/vmx/nested.c:6220 [inline]
   nested_vmx_free_vcpu+0x83/0xc0 arch/x86/kvm/vmx/nested.c:330
   vmx_free_vcpu+0x11f/0x2a0 arch/x86/kvm/vmx/vmx.c:6799
   kvm_arch_vcpu_destroy+0x6b/0x240 arch/x86/kvm/x86.c:10989
   kvm_vcpu_destroy+0x29/0x90 arch/x86/kvm/../../../virt/kvm/kvm_main.c:441
   kvm_free_vcpus arch/x86/kvm/x86.c:11426 [inline]
   kvm_arch_destroy_vm+0x3ef/0x6b0 arch/x86/kvm/x86.c:11545
   kvm_destroy_vm arch/x86/kvm/../../../virt/kvm/kvm_main.c:1189 [inline]
   kvm_put_kvm+0x751/0xe40 arch/x86/kvm/../../../virt/kvm/kvm_main.c:1220
   kvm_vcpu_release+0x53/0x60 arch/x86/kvm/../../../virt/kvm/kvm_main.c:3489
   __fput+0x3fc/0x870 fs/file_table.c:280
   task_work_run+0x146/0x1c0 kernel/task_work.c:164
   exit_task_work include/linux/task_work.h:32 [inline]
   do_exit+0x705/0x24f0 kernel/exit.c:832
   do_group_exit+0x168/0x2d0 kernel/exit.c:929
   get_signal+0x1740/0x2120 kernel/signal.c:2852
   arch_do_signal_or_restart+0x9c/0x730 arch/x86/kernel/signal.c:868
   handle_signal_work kernel/entry/common.c:148 [inline]
   exit_to_user_mode_loop kernel/entry/common.c:172 [inline]
   exit_to_user_mode_prepare+0x191/0x220 kernel/entry/common.c:207
   __syscall_exit_to_user_mode_work kernel/entry/common.c:289 [inline]
   syscall_exit_to_user_mode+0x2e/0x70 kernel/entry/common.c:300
   do_syscall_64+0x53/0xd0 arch/x86/entry/common.c:86
   entry_SYSCALL_64_after_hwframe+0x44/0xae

Fixes: c8607e4a

 ("KVM: x86: nVMX: don't fail nested VM entry on invalid guest state if !from_vmentry")
Reported-by: default avatar <syzbot+f1d2136db9c80d4733e8@syzkaller.appspotmail.com>
Reviewed-by: default avatarMaxim Levitsky <mlevitsk@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
Message-Id: <20211207193006.120997-2-seanjc@google.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      a80dfc02
    • Andrew Jones's avatar
      selftests: KVM: Fix non-x86 compiling · 577e022b
      Andrew Jones authored 
      Attempting to compile on a non-x86 architecture fails with

include/kvm_util.h: In function ‘vm_compute_max_gfn’:
include/kvm_util.h:79:21: error: dereferencing pointer to incomplete type ‘struct kvm_vm’
  return ((1ULL << vm->pa_bits) >> vm->page_shift) - 1;
                     ^~

This is because the declaration of struct kvm_vm is in
lib/kvm_util_internal.h as an effort to make it private to
the test lib code. We can still provide arch specific functions,
though, by making the generic function symbols weak. Do that to
fix the compile error.

Fixes: c8cc43c1

 ("selftests: KVM: avoid failures due to reserved HyperTransport region")
Cc: stable@vger.kernel.org
Signed-off-by: default avatarAndrew Jones <drjones@redhat.com>
Message-Id: <20211214151842.848314-1-drjones@redhat.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      577e022b
    • Marc Orr's avatar
      KVM: x86: Always set kvm_run->if_flag · c5063551
      Marc Orr authored 
      The kvm_run struct's if_flag is a part of the userspace/kernel API. The
SEV-ES patches failed to set this flag because it's no longer needed by
QEMU (according to the comment in the source code). However, other
hypervisors may make use of this flag. Therefore, set the flag for
guests with encrypted registers (i.e., with guest_state_protected set).

Fixes: f1c6366e

 ("KVM: SVM: Add required changes to support intercepts under SEV-ES")
Signed-off-by: default avatarMarc Orr <marcorr@google.com>
Message-Id: <20211209155257.128747-1-marcorr@google.com>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Reviewed-by: default avatarMaxim Levitsky <mlevitsk@redhat.com>
      c5063551
    • Sean Christopherson's avatar
      KVM: x86/mmu: Don't advance iterator after restart due to yielding · 3a0f64de
      Sean Christopherson authored 
      After dropping mmu_lock in the TDP MMU, restart the iterator during
tdp_iter_next() and do not advance the iterator.  Advancing the iterator
results in skipping the top-level SPTE and all its children, which is
fatal if any of the skipped SPTEs were not visited before yielding.

When zapping all SPTEs, i.e. when min_level == root_level, restarting the
iter and then invoking tdp_iter_next() is always fatal if the current gfn
has as a valid SPTE, as advancing the iterator results in try_step_side()
skipping the current gfn, which wasn't visited before yielding.

Sprinkle WARNs on iter->yielded being true in various helpers that are
often used in conjunction with yielding, and tag the helper with
__must_check to reduce the probabily of improper usage.

Failing to zap a top-level SPTE manifests in one of two ways.  If a valid
SPTE is skipped by both kvm_tdp_mmu_zap_all() and kvm_tdp_mmu_put_root(),
the shadow page will be leaked and KVM will WARN accordingly.

  WARNING: CPU: 1 PID: 3509 at arch/x86/kvm/mmu/tdp_mmu.c:46 [kvm]
  RIP: 0010:kvm_mmu_uninit_tdp_mmu+0x3e/0x50 [kvm]
  Call Trace:
   <TASK>
   kvm_arch_destroy_vm+0x130/0x1b0 [kvm]
   kvm_destroy_vm+0x162/0x2a0 [kvm]
   kvm_vcpu_release+0x34/0x60 [kvm]
   __fput+0x82/0x240
   task_work_run+0x5c/0x90
   do_exit+0x364/0xa10
   ? futex_unqueue+0x38/0x60
   do_group_exit+0x33/0xa0
   get_signal+0x155/0x850
   arch_do_signal_or_restart+0xed/0x750
   exit_to_user_mode_prepare+0xc5/0x120
   syscall_exit_to_user_mode+0x1d/0x40
   do_syscall_64+0x48/0xc0
   entry_SYSCALL_64_after_hwframe+0x44/0xae

If kvm_tdp_mmu_zap_all() skips a gfn/SPTE but that SPTE is then zapped by
kvm_tdp_mmu_put_root(), KVM triggers a use-after-free in the form of
marking a struct page as dirty/accessed after it has been put back on the
free list.  This directly triggers a WARN due to encountering a page with
page_count() == 0, but it can also lead to data corruption and additional
errors in the kernel.

  WARNING: CPU: 7 PID: 1995658 at arch/x86/kvm/../../../virt/kvm/kvm_main.c:171
  RIP: 0010:kvm_is_zone_device_pfn.part.0+0x9e/0xd0 [kvm]
  Call Trace:
   <TASK>
   kvm_set_pfn_dirty+0x120/0x1d0 [kvm]
   __handle_changed_spte+0x92e/0xca0 [kvm]
   __handle_changed_spte+0x63c/0xca0 [kvm]
   __handle_changed_spte+0x63c/0xca0 [kvm]
   __handle_changed_spte+0x63c/0xca0 [kvm]
   zap_gfn_range+0x549/0x620 [kvm]
   kvm_tdp_mmu_put_root+0x1b6/0x270 [kvm]
   mmu_free_root_page+0x219/0x2c0 [kvm]
   kvm_mmu_free_roots+0x1b4/0x4e0 [kvm]
   kvm_mmu_unload+0x1c/0xa0 [kvm]
   kvm_arch_destroy_vm+0x1f2/0x5c0 [kvm]
   kvm_put_kvm+0x3b1/0x8b0 [kvm]
   kvm_vcpu_release+0x4e/0x70 [kvm]
   __fput+0x1f7/0x8c0
   task_work_run+0xf8/0x1a0
   do_exit+0x97b/0x2230
   do_group_exit+0xda/0x2a0
   get_signal+0x3be/0x1e50
   arch_do_signal_or_restart+0x244/0x17f0
   exit_to_user_mode_prepare+0xcb/0x120
   syscall_exit_to_user_mode+0x1d/0x40
   do_syscall_64+0x4d/0x90
   entry_SYSCALL_64_after_hwframe+0x44/0xae

Note, the underlying bug existed even before commit 1af4a960 ("KVM:
x86/mmu: Yield in TDU MMU iter even if no SPTES changed") moved calls to
tdp_mmu_iter_cond_resched() to the beginning of loops, as KVM could still
incorrectly advance past a top-level entry when yielding on a lower-level
entry.  But with respect to leaking shadow pages, the bug was introduced
by yielding before processing the current gfn.

Alternatively, tdp_mmu_iter_cond_resched() could simply fall through, or
callers could jump to their "retry" label.  The downside of that approach
is that tdp_mmu_iter_cond_resched() _must_ be called before anything else
in the loop, and there's no easy way to enfornce that requirement.

Ideally, KVM would handling the cond_resched() fully within the iterator
macro (the code is actually quite clean) and avoid this entire class of
bugs, but that is extremely difficult do while also supporting yielding
after tdp_mmu_set_spte_atomic() fails.  Yielding after failing to set a
SPTE is very desirable as the "owner" of the REMOVED_SPTE isn't strictly
bounded, e.g. if it's zapping a high-level shadow page, the REMOVED_SPTE
may block operations on the SPTE for a significant amount of time.

Fixes: faaf05b0 ("kvm: x86/mmu: Support zapping SPTEs in the TDP MMU")
Fixes: 1af4a960

 ("KVM: x86/mmu: Yield in TDU MMU iter even if no SPTES changed")
Reported-by: default avatarIgnat Korchagin <ignat@cloudflare.com>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
Message-Id: <20211214033528.123268-1-seanjc@google.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      3a0f64de
    • 蒋家盛's avatar
      HID: potential dereference of null pointer · 13251ce1
      蒋家盛 authored 
      The return value of devm_kzalloc() needs to be checked.
To avoid hdev->dev->driver_data to be null in case of the failure of
alloc.

Fixes: 14c9c014

 ("HID: add vivaldi HID driver")
Cc: stable@vger.kernel.org
Signed-off-by: default avatarJiasheng Jiang <jiasheng@iscas.ac.cn>
Signed-off-by: default avatarBenjamin Tissoires <benjamin.tissoires@redhat.com>
Link: https://lore.kernel.org/r/20211215083605.117638-1-jiasheng@iscas.ac.cn
      13251ce1
    • Benjamin Tissoires's avatar
      HID: holtek: fix mouse probing · 93a2207c
      Benjamin Tissoires authored 
      An overlook from the previous commit: we don't even parse or start the
device, meaning that the device is not presented to user space.

Fixes: 93020953 ("HID: check for valid USB device for many HID drivers")
Cc: stable@vger.kernel.org
Link: https://bugs.archlinux.org/task/73048
Link: https://bugzilla.kernel.org/show_bug.cgi?id=215341
Link: https://lore.kernel.org/r/e4efbf13-bd8d-0370-629b-6c80c0044b15@leemhuis.info/


Signed-off-by: default avatarBenjamin Tissoires <benjamin.tissoires@redhat.com>
      93a2207c
    • Wei Wang's avatar
      KVM: x86: remove PMU FIXED_CTR3 from msrs_to_save_all · 9fb12fe5
      Wei Wang authored 
      

The fixed counter 3 is used for the Topdown metrics, which hasn't been
enabled for KVM guests. Userspace accessing to it will fail as it's not
included in get_fixed_pmc(). This breaks KVM selftests on ICX+ machines,
which have this counter.

To reproduce it on ICX+ machines, ./state_test reports:
==== Test Assertion Failure ====
lib/x86_64/processor.c:1078: r == nmsrs
pid=4564 tid=4564 - Argument list too long
1  0x000000000040b1b9: vcpu_save_state at processor.c:1077
2  0x0000000000402478: main at state_test.c:209 (discriminator 6)
3  0x00007fbe21ed5f92: ?? ??:0
4  0x000000000040264d: _start at ??:?
 Unexpected result from KVM_GET_MSRS, r: 17 (failed MSR was 0x30c)

With this patch, it works well.

Signed-off-by: default avatarWei Wang <wei.w.wang@intel.com>
Message-Id: <20211217124934.32893-1-wei.w.wang@intel.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      9fb12fe5
    • Linus Torvalds's avatar
      Linux 5.16-rc6 · a7904a53
      Linus Torvalds authored
      a7904a53