[LTS 8.6] imon: CVE-2025-39993, kvm: CVE-2026-23401, CVE-2023-30456, CVE-2022-45869, CVE-2022-1852#1356
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[LTS 8.6] imon: CVE-2025-39993, kvm: CVE-2026-23401, CVE-2023-30456, CVE-2022-45869, CVE-2022-1852#1356pvts-mat wants to merge 9 commits into
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…IO SPTE jira VULN-180393 cve CVE-2026-23401 commit-author Sean Christopherson <seanjc@google.com> commit aad885e upstream-diff Used linux-5.15.y's backport 20656cd1f243d3a154aac5dd1b823110b6906fe1 for the clean cherry-pick. Just like that version the LTS 8.6 misses 1075d41 ("KVM: x86/mmu: Expand and clean up page fault stats"). Strictly speaking, the upstream's `kvm_flush_remote_tlbs_gfn(vcpu->kvm, gfn, level)' call corresponds to LTS 8.6-native `kvm_flush_remote_tlbs_with_address(vcpu->kvm, gfn & -KVM_PAGES_PER_HPAGE(level), KVM_PAGES_PER_HPAGE(level))'. See the non-backported commits: - 9ffe926 ("KVM: x86/mmu: Fix wrong gfn range of tlb flushing in kvm_set_pte_rmapp()"), - 8c63e8c ("KVM: x86/mmu: Rename kvm_flush_remote_tlbs_with_address()"), - c667a3b ("KVM: x86/mmu: Move round_gfn_for_level() helper into mmu_internal.h"). Nevertheless preserved linux-5.15.y's `kvm_flush_remote_tlbs_with_address()' call without `gfn' rounding, as that's exactly how it's used in the same function a few lines later, strongly suggesting that the issues raised in commit 9ffe926 don't apply here. When installing an emulated MMIO SPTE, do so *after* dropping/zapping the existing SPTE (if it's shadow-present). While commit a54aa15 was right about it being impossible to convert a shadow-present SPTE to an MMIO SPTE due to a _guest_ write, it failed to account for writes to guest memory that are outside the scope of KVM. E.g. if host userspace modifies a shadowed gPTE to switch from a memslot to emulted MMIO and then the guest hits a relevant page fault, KVM will install the MMIO SPTE without first zapping the shadow-present SPTE. ------------[ cut here ]------------ is_shadow_present_pte(*sptep) WARNING: arch/x86/kvm/mmu/mmu.c:484 at mark_mmio_spte+0xb2/0xc0 [kvm], CPU#0: vmx_ept_stale_r/4292 Modules linked in: kvm_intel kvm irqbypass CPU: 0 UID: 1000 PID: 4292 Comm: vmx_ept_stale_r Not tainted 7.0.0-rc2-eafebd2d2ab0-sink-vm ctrliq#319 PREEMPT Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 RIP: 0010:mark_mmio_spte+0xb2/0xc0 [kvm] Call Trace: <TASK> mmu_set_spte+0x237/0x440 [kvm] ept_page_fault+0x535/0x7f0 [kvm] kvm_mmu_do_page_fault+0xee/0x1f0 [kvm] kvm_mmu_page_fault+0x8d/0x620 [kvm] vmx_handle_exit+0x18c/0x5a0 [kvm_intel] kvm_arch_vcpu_ioctl_run+0xc55/0x1c20 [kvm] kvm_vcpu_ioctl+0x2d5/0x980 [kvm] __x64_sys_ioctl+0x8a/0xd0 do_syscall_64+0xb5/0x730 entry_SYSCALL_64_after_hwframe+0x4b/0x53 RIP: 0033:0x47fa3f </TASK> ---[ end trace 0000000000000000 ]--- Reported-by: Alexander Bulekov <bkov@amazon.com> Debugged-by: Alexander Bulekov <bkov@amazon.com> Suggested-by: Fred Griffoul <fgriffo@amazon.co.uk> Fixes: a54aa15 ("KVM: x86/mmu: Handle MMIO SPTEs directly in mmu_set_spte()") Cc: stable@vger.kernel.org Signed-off-by: Sean Christopherson <seanjc@google.com> (cherry picked from commit 20656cd1f243d3a154aac5dd1b823110b6906fe1) Signed-off-by: Marcin Wcisło <marcin.wcislo@conclusive.pl>
jira VULN-158816 cve-pre CVE-2025-39993 commit-author Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> commit db264d4 upstream-diff Context conflict solved due to missing cf33069 ("media: rc: Add support for another iMON 0xffdc device") Since usb_register_dev() from imon_init_display() from imon_probe() holds minor_rwsem while display_open() which holds driver_lock and ictx->lock is called with minor_rwsem held from usb_open(), holding driver_lock or ictx->lock when calling usb_register_dev() causes circular locking dependency problem. Since usb_deregister_dev() from imon_disconnect() holds minor_rwsem while display_open() which holds driver_lock is called with minor_rwsem held, holding driver_lock when calling usb_deregister_dev() also causes circular locking dependency problem. Sean Young explained that the problem is there are imon devices which have two usb interfaces, even though it is one device. The probe and disconnect function of both usb interfaces can run concurrently. Alan Stern responded that the driver and USB cores guarantee that when an interface is probed, both the interface and its USB device are locked. Ditto for when the disconnect callback gets run. So concurrent probing/ disconnection of multiple interfaces on the same device is not possible. Therefore, we don't need locks for handling race between imon_probe() and imon_disconnect(). But we still need to handle race between display_open() /vfd_write()/lcd_write()/display_close() and imon_disconnect(), for disconnect event can happen while file descriptors are in use. Since "struct file"->private_data is set by display_open(), vfd_write()/ lcd_write()/display_close() can assume that "struct file"->private_data is not NULL even after usb_set_intfdata(interface, NULL) was called. Replace insufficiently held driver_lock with refcount_t based management. Add a boolean flag for recording whether imon_disconnect() was already called. Use RCU for accessing this boolean flag and refcount_t. Since the boolean flag for imon_disconnect() is shared, disconnect event on either intf0 or intf1 affects both interfaces. But I assume that this change does not matter, for usually disconnect event would not happen while interfaces are in use. Link: https://syzkaller.appspot.com/bug?extid=c558267ad910fc494497 Reported-by: syzbot <syzbot+c558267ad910fc494497@syzkaller.appspotmail.com> Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Tested-by: syzbot <syzbot+c558267ad910fc494497@syzkaller.appspotmail.com> Cc: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Sean Young <sean@mess.org> Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org> (cherry picked from commit db264d4) Signed-off-by: Marcin Wcisło <marcin.wcislo@conclusive.pl>
jira VULN-158816 cve-pre CVE-2025-39993 commit-author Gautam Menghani <gautammenghani201@gmail.com> commit 813ceef The function send_packet() has a race condition as follows: func send_packet() { // do work call usb_submit_urb() mutex_unlock() wait_for_event_interruptible() <-- lock gone mutex_lock() } func vfd_write() { mutex_lock() call send_packet() <- prev call is not completed mutex_unlock() } When the mutex is unlocked and the function send_packet() waits for the call to complete, vfd_write() can start another call, which leads to the "URB submitted while active" warning in usb_submit_urb(). Fix this by removing the mutex_unlock() call in send_packet() and using mutex_lock_interruptible(). Link: https://syzkaller.appspot.com/bug?id=e378e6a51fbe6c5cc43e34f131cc9a315ef0337e Fixes: 21677cf ("V4L/DVB: ir-core: add imon driver") Reported-by: syzbot+0c3cb6dc05fbbdc3ad66@syzkaller.appspotmail.com Signed-off-by: Gautam Menghani <gautammenghani201@gmail.com> Signed-off-by: Sean Young <sean@mess.org> Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org> (cherry picked from commit 813ceef) Signed-off-by: Marcin Wcisło <marcin.wcislo@conclusive.pl>
jira VULN-158816 cve-pre CVE-2025-39993 commit-author Ricardo Ribalda <ribalda@chromium.org> commit 2414789 Lets fix a race between mutex_is_lock() and mutex_lock(). <-mutex is not locked if (!mutex_is_locked(&ictx->lock)) { unlock = true; <- mutex is locked externaly mutex_lock(&ictx->lock); } Let's use mutex_trylock() that does mutex_is_lock() and mutex_lock() atomically. Fix the following cocci warning: drivers/media/rc/imon.c:1167:1-7: preceding lock on line 1153 Fixes: 23ef710 ("[media] imon: add conditional locking in change_protocol") Signed-off-by: Ricardo Ribalda <ribalda@chromium.org> Signed-off-by: Sean Young <sean@mess.org> Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl> (cherry picked from commit 2414789) Signed-off-by: Marcin Wcisło <marcin.wcislo@conclusive.pl>
jira VULN-158816 cve-pre CVE-2025-39993 commit-author Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> commit 7019553 Move mutex_trylock() in imon_ir_change_protocol() to the beginning, for memcpy() which modifies ictx->usb_tx_buf should be protected by ictx->lock. Also, verify at the beginning of send_packet() that ictx->lock is held in case send_packet() is by error called from imon_ir_change_protocol() when mutex_trylock() failed due to concurrent requests. Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Signed-off-by: Sean Young <sean@mess.org> Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org> (cherry picked from commit 7019553) Signed-off-by: Marcin Wcisło <marcin.wcislo@conclusive.pl>
jira VULN-158816 cve CVE-2025-39993 commit-author Larshin Sergey <Sergey.Larshin@kaspersky.com> commit fa0f61c Syzbot reports a KASAN issue as below: BUG: KASAN: use-after-free in __create_pipe include/linux/usb.h:1945 [inline] BUG: KASAN: use-after-free in send_packet+0xa2d/0xbc0 drivers/media/rc/imon.c:627 Read of size 4 at addr ffff8880256fb000 by task syz-executor314/4465 CPU: 2 PID: 4465 Comm: syz-executor314 Not tainted 6.0.0-rc1-syzkaller #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014 Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 print_address_description mm/kasan/report.c:317 [inline] print_report.cold+0x2ba/0x6e9 mm/kasan/report.c:433 kasan_report+0xb1/0x1e0 mm/kasan/report.c:495 __create_pipe include/linux/usb.h:1945 [inline] send_packet+0xa2d/0xbc0 drivers/media/rc/imon.c:627 vfd_write+0x2d9/0x550 drivers/media/rc/imon.c:991 vfs_write+0x2d7/0xdd0 fs/read_write.c:576 ksys_write+0x127/0x250 fs/read_write.c:631 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd The iMON driver improperly releases the usb_device reference in imon_disconnect without coordinating with active users of the device. Specifically, the fields usbdev_intf0 and usbdev_intf1 are not protected by the users counter (ictx->users). During probe, imon_init_intf0 or imon_init_intf1 increments the usb_device reference count depending on the interface. However, during disconnect, usb_put_dev is called unconditionally, regardless of actual usage. As a result, if vfd_write or other operations are still in progress after disconnect, this can lead to a use-after-free of the usb_device pointer. Thread 1 vfd_write Thread 2 imon_disconnect ... if usb_put_dev(ictx->usbdev_intf0) else usb_put_dev(ictx->usbdev_intf1) ... while send_packet if pipe = usb_sndintpipe( ictx->usbdev_intf0) UAF else pipe = usb_sndctrlpipe( ictx->usbdev_intf0, 0) UAF Guard access to usbdev_intf0 and usbdev_intf1 after disconnect by checking ictx->disconnected in all writer paths. Add early return with -ENODEV in send_packet(), vfd_write(), lcd_write() and display_open() if the device is no longer present. Set and read ictx->disconnected under ictx->lock to ensure memory synchronization. Acquire the lock in imon_disconnect() before setting the flag to synchronize with any ongoing operations. Ensure writers exit early and safely after disconnect before the USB core proceeds with cleanup. Found by Linux Verification Center (linuxtesting.org) with Syzkaller. Reported-by: syzbot+f1a69784f6efe748c3bf@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=f1a69784f6efe748c3bf Fixes: 21677cf ("V4L/DVB: ir-core: add imon driver") Cc: stable@vger.kernel.org Signed-off-by: Larshin Sergey <Sergey.Larshin@kaspersky.com> Signed-off-by: Sean Young <sean@mess.org> Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org> (cherry picked from commit fa0f61c) Signed-off-by: Marcin Wcisło <marcin.wcislo@conclusive.pl>
jira VULN-3974 cve CVE-2023-30456 commit-author Paolo Bonzini <pbonzini@redhat.com> commit 112e660 The effective values of the guest CR0 and CR4 registers may differ from those included in the VMCS12. In particular, disabling EPT forces CR4.PAE=1 and disabling unrestricted guest mode forces CR0.PG=CR0.PE=1. Therefore, checks on these bits cannot be delegated to the processor and must be performed by KVM. Reported-by: Reima ISHII <ishiir@g.ecc.u-tokyo.ac.jp> Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> (cherry picked from commit 112e660) Signed-off-by: Marcin Wcisło <marcin.wcislo@conclusive.pl>
jira VULN-3954 cve CVE-2022-45869 commit-author Kazuki Takiguchi <takiguchi.kazuki171@gmail.com> commit 47b0c2e upstream-diff Used linux-5.15.y backport f88a697 for the clean pick. The modified function `direct_page_fault' is the same in both versions make_mmu_pages_available() must be called with mmu_lock held for write. However, if the TDP MMU is used, it will be called with mmu_lock held for read. This function does nothing unless shadow pages are used, so there is no race unless nested TDP is used. Since nested TDP uses shadow pages, old shadow pages may be zapped by this function even when the TDP MMU is enabled. Since shadow pages are never allocated by kvm_tdp_mmu_map(), a race condition can be avoided by not calling make_mmu_pages_available() if the TDP MMU is currently in use. I encountered this when repeatedly starting and stopping nested VM. It can be artificially caused by allocating a large number of nested TDP SPTEs. For example, the following BUG and general protection fault are caused in the host kernel. pte_list_remove: 00000000cd54fc10 many->many ------------[ cut here ]------------ kernel BUG at arch/x86/kvm/mmu/mmu.c:963! invalid opcode: 0000 [ctrliq#1] PREEMPT SMP NOPTI RIP: 0010:pte_list_remove.cold+0x16/0x48 [kvm] Call Trace: <TASK> drop_spte+0xe0/0x180 [kvm] mmu_page_zap_pte+0x4f/0x140 [kvm] __kvm_mmu_prepare_zap_page+0x62/0x3e0 [kvm] kvm_mmu_zap_oldest_mmu_pages+0x7d/0xf0 [kvm] direct_page_fault+0x3cb/0x9b0 [kvm] kvm_tdp_page_fault+0x2c/0xa0 [kvm] kvm_mmu_page_fault+0x207/0x930 [kvm] npf_interception+0x47/0xb0 [kvm_amd] svm_invoke_exit_handler+0x13c/0x1a0 [kvm_amd] svm_handle_exit+0xfc/0x2c0 [kvm_amd] kvm_arch_vcpu_ioctl_run+0xa79/0x1780 [kvm] kvm_vcpu_ioctl+0x29b/0x6f0 [kvm] __x64_sys_ioctl+0x95/0xd0 do_syscall_64+0x5c/0x90 general protection fault, probably for non-canonical address 0xdead000000000122: 0000 [ctrliq#1] PREEMPT SMP NOPTI RIP: 0010:kvm_mmu_commit_zap_page.part.0+0x4b/0xe0 [kvm] Call Trace: <TASK> kvm_mmu_zap_oldest_mmu_pages+0xae/0xf0 [kvm] direct_page_fault+0x3cb/0x9b0 [kvm] kvm_tdp_page_fault+0x2c/0xa0 [kvm] kvm_mmu_page_fault+0x207/0x930 [kvm] npf_interception+0x47/0xb0 [kvm_amd] CVE: CVE-2022-45869 Fixes: a2855af ("KVM: x86/mmu: Allow parallel page faults for the TDP MMU") Signed-off-by: Kazuki Takiguchi <takiguchi.kazuki171@gmail.com> Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> (cherry picked from commit f88a697) Signed-off-by: Marcin Wcisło <marcin.wcislo@conclusive.pl>
jira VULN-3154 cve CVE-2022-1852 commit-author Sean Christopherson <seanjc@google.com> commit fee060c Whenever x86_decode_emulated_instruction() detects a breakpoint, it returns the value that kvm_vcpu_check_breakpoint() writes into its pass-by-reference second argument. Unfortunately this is completely bogus because the expected outcome of x86_decode_emulated_instruction is an EMULATION_* value. Then, if kvm_vcpu_check_breakpoint() does "*r = 0" (corresponding to a KVM_EXIT_DEBUG userspace exit), it is misunderstood as EMULATION_OK and x86_emulate_instruction() is called without having decoded the instruction. This causes various havoc from running with a stale emulation context. The fix is to move the call to kvm_vcpu_check_breakpoint() where it was before commit 4aa2691 ("KVM: x86: Factor out x86 instruction emulation with decoding") introduced x86_decode_emulated_instruction(). The other caller of the function does not need breakpoint checks, because it is invoked as part of a vmexit and the processor has already checked those before executing the instruction that #GP'd. This fixes CVE-2022-1852. Reported-by: Qiuhao Li <qiuhao@sysec.org> Reported-by: Gaoning Pan <pgn@zju.edu.cn> Reported-by: Yongkang Jia <kangel@zju.edu.cn> Fixes: 4aa2691 ("KVM: x86: Factor out x86 instruction emulation with decoding") Cc: stable@vger.kernel.org Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20220311032801.3467418-2-seanjc@google.com> [Rewrote commit message according to Qiuhao's report, since a patch already existed to fix the bug. - Paolo] Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> (cherry picked from commit fee060c) Signed-off-by: Marcin Wcisło <marcin.wcislo@conclusive.pl>
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[LTS 8.6]
Commits
CVE-2022-1852
CVE-2022-45869
CVE-2023-30456
CVE-2025-39993
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The
imonmodule had a bunch of synchronization fixes building one upon the other. This batch of prerequisites follows the general pattern found in other versions having CVE-2025-39993 fix backported:CVE-2026-23401
For details see the PR for the LTS 9.2 solution with the same situation.
kABI check: passed
Boot test: passed
boot-test.log
Kselftests: passed relative
Reference
kselftests–ciqlts8_6–run1.log
kselftests–ciqlts8_6–run2.log
kselftests–ciqlts8_6–run3.log
Patch
kselftests–ciqlts8_6-CVE-batch-36–run1.log
kselftests–ciqlts8_6-CVE-batch-36–run2.log
kselftests–ciqlts8_6-CVE-batch-36–run3.log
Comparison
The tests results for the reference and the patch are the same.
full-tests-results-comparison.log