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[PATCH OLK-6.6] x86/fpu: Clear XSTATE_BV[i] in guest XSAVE state whenever XFD[i]=1
by Zhang Kunbo 28 Jan '26

28 Jan '26

From: Sean Christopherson <seanjc(a)google.com> stable inclusion from stable-v6.12.67 commit f577508cc8a0adb8b4ebe9480bba7683b6149930 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/13516 CVE: CVE-2026-23005 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id… -------------------------------- commit b45f721775947a84996deb5c661602254ce25ce6 upstream. When loading guest XSAVE state via KVM_SET_XSAVE, and when updating XFD in response to a guest WRMSR, clear XFD-disabled features in the saved (or to be restored) XSTATE_BV to ensure KVM doesn't attempt to load state for features that are disabled via the guest's XFD. Because the kernel executes XRSTOR with the guest's XFD, saving XSTATE_BV[i]=1 with XFD[i]=1 will cause XRSTOR to #NM and panic the kernel. E.g. if fpu_update_guest_xfd() sets XFD without clearing XSTATE_BV: ------------[ cut here ]------------ WARNING: arch/x86/kernel/traps.c:1524 at exc_device_not_available+0x101/0x110, CPU#29: amx_test/848 Modules linked in: kvm_intel kvm irqbypass CPU: 29 UID: 1000 PID: 848 Comm: amx_test Not tainted 6.19.0-rc2-ffa07f7fd437-x86_amx_nm_xfd_non_init-vm #171 NONE Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 RIP: 0010:exc_device_not_available+0x101/0x110 Call Trace: <TASK> asm_exc_device_not_available+0x1a/0x20 RIP: 0010:restore_fpregs_from_fpstate+0x36/0x90 switch_fpu_return+0x4a/0xb0 kvm_arch_vcpu_ioctl_run+0x1245/0x1e40 [kvm] kvm_vcpu_ioctl+0x2c3/0x8f0 [kvm] __x64_sys_ioctl+0x8f/0xd0 do_syscall_64+0x62/0x940 entry_SYSCALL_64_after_hwframe+0x4b/0x53 </TASK> ---[ end trace 0000000000000000 ]--- This can happen if the guest executes WRMSR(MSR_IA32_XFD) to set XFD[18] = 1, and a host IRQ triggers kernel_fpu_begin() prior to the vmexit handler's call to fpu_update_guest_xfd(). and if userspace stuffs XSTATE_BV[i]=1 via KVM_SET_XSAVE: ------------[ cut here ]------------ WARNING: arch/x86/kernel/traps.c:1524 at exc_device_not_available+0x101/0x110, CPU#14: amx_test/867 Modules linked in: kvm_intel kvm irqbypass CPU: 14 UID: 1000 PID: 867 Comm: amx_test Not tainted 6.19.0-rc2-2dace9faccd6-x86_amx_nm_xfd_non_init-vm #168 NONE Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 RIP: 0010:exc_device_not_available+0x101/0x110 Call Trace: <TASK> asm_exc_device_not_available+0x1a/0x20 RIP: 0010:restore_fpregs_from_fpstate+0x36/0x90 fpu_swap_kvm_fpstate+0x6b/0x120 kvm_load_guest_fpu+0x30/0x80 [kvm] kvm_arch_vcpu_ioctl_run+0x85/0x1e40 [kvm] kvm_vcpu_ioctl+0x2c3/0x8f0 [kvm] __x64_sys_ioctl+0x8f/0xd0 do_syscall_64+0x62/0x940 entry_SYSCALL_64_after_hwframe+0x4b/0x53 </TASK> ---[ end trace 0000000000000000 ]--- The new behavior is consistent with the AMX architecture. Per Intel's SDM, XSAVE saves XSTATE_BV as '0' for components that are disabled via XFD (and non-compacted XSAVE saves the initial configuration of the state component): If XSAVE, XSAVEC, XSAVEOPT, or XSAVES is saving the state component i, the instruction does not generate #NM when XCR0[i] = IA32_XFD[i] = 1; instead, it operates as if XINUSE[i] = 0 (and the state component was in its initial state): it saves bit i of XSTATE_BV field of the XSAVE header as 0; in addition, XSAVE saves the initial configuration of the state component (the other instructions do not save state component i). Alternatively, KVM could always do XRSTOR with XFD=0, e.g. by using a constant XFD based on the set of enabled features when XSAVEing for a struct fpu_guest. However, having XSTATE_BV[i]=1 for XFD-disabled features can only happen in the above interrupt case, or in similar scenarios involving preemption on preemptible kernels, because fpu_swap_kvm_fpstate()'s call to save_fpregs_to_fpstate() saves the outgoing FPU state with the current XFD; and that is (on all but the first WRMSR to XFD) the guest XFD. Therefore, XFD can only go out of sync with XSTATE_BV in the above interrupt case, or in similar scenarios involving preemption on preemptible kernels, and it we can consider it (de facto) part of KVM ABI that KVM_GET_XSAVE returns XSTATE_BV[i]=0 for XFD-disabled features. Reported-by: Paolo Bonzini <pbonzini(a)redhat.com> Cc: stable(a)vger.kernel.org Fixes: 820a6ee944e7 ("kvm: x86: Add emulation for IA32_XFD", 2022-01-14) Signed-off-by: Sean Christopherson <seanjc(a)google.com> [Move clearing of XSTATE_BV from fpu_copy_uabi_to_guest_fpstate to kvm_vcpu_ioctl_x86_set_xsave. - Paolo] Reviewed-by: Binbin Wu <binbin.wu(a)linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini(a)redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Conflicts: arch/x86/kvm/x86.c [Context difference. ] Signed-off-by: Zhang Kunbo <zhangkunbo(a)huawei.com> --- arch/x86/kernel/fpu/core.c | 32 +++++++++++++++++++++++++++++--- arch/x86/kvm/x86.c | 9 +++++++++ 2 files changed, 38 insertions(+), 3 deletions(-) diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c index 1f0871be9d53..fd53ff26cd42 100644 --- a/arch/x86/kernel/fpu/core.c +++ b/arch/x86/kernel/fpu/core.c @@ -296,10 +296,29 @@ EXPORT_SYMBOL_GPL(fpu_enable_guest_xfd_features); #ifdef CONFIG_X86_64 void fpu_update_guest_xfd(struct fpu_guest *guest_fpu, u64 xfd) { + struct fpstate *fpstate = guest_fpu->fpstate; + fpregs_lock(); - guest_fpu->fpstate->xfd = xfd; - if (guest_fpu->fpstate->in_use) - xfd_update_state(guest_fpu->fpstate); + + /* + * KVM's guest ABI is that setting XFD[i]=1 *can* immediately revert the + * save state to its initial configuration. Likewise, KVM_GET_XSAVE does + * the same as XSAVE and returns XSTATE_BV[i]=0 whenever XFD[i]=1. + * + * If the guest's FPU state is in hardware, just update XFD: the XSAVE + * in fpu_swap_kvm_fpstate will clear XSTATE_BV[i] whenever XFD[i]=1. + * + * If however the guest's FPU state is NOT resident in hardware, clear + * disabled components in XSTATE_BV now, or a subsequent XRSTOR will + * attempt to load disabled components and generate #NM _in the host_. + */ + if (xfd && test_thread_flag(TIF_NEED_FPU_LOAD)) + fpstate->regs.xsave.header.xfeatures &= ~xfd; + + fpstate->xfd = xfd; + if (fpstate->in_use) + xfd_update_state(fpstate); + fpregs_unlock(); } EXPORT_SYMBOL_GPL(fpu_update_guest_xfd); @@ -407,6 +426,13 @@ int fpu_copy_uabi_to_guest_fpstate(struct fpu_guest *gfpu, const void *buf, if (ustate->xsave.header.xfeatures & ~xcr0) return -EINVAL; + /* + * Disabled features must be in their initial state, otherwise XRSTOR + * causes an exception. + */ + if (WARN_ON_ONCE(ustate->xsave.header.xfeatures & kstate->xfd)) + return -EINVAL; + /* * Nullify @vpkru to preserve its current value if PKRU's bit isn't set * in the header. KVM's odd ABI is to leave PKRU untouched in this diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 2139f728aecc..57fc6916906b 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -5541,9 +5541,18 @@ static void kvm_vcpu_ioctl_x86_get_xsave(struct kvm_vcpu *vcpu, static int kvm_vcpu_ioctl_x86_set_xsave(struct kvm_vcpu *vcpu, struct kvm_xsave *guest_xsave) { + union fpregs_state *xstate = (union fpregs_state *)guest_xsave->region; + if (fpstate_is_confidential(&vcpu->arch.guest_fpu)) return 0; + /* + * For backwards compatibility, do not expect disabled features to be in + * their initial state. XSTATE_BV[i] must still be cleared whenever + * XFD[i]=1, or XRSTOR would cause a #NM. + */ + xstate->xsave.header.xfeatures &= ~vcpu->arch.guest_fpu.fpstate->xfd; + return fpu_copy_uabi_to_guest_fpstate(&vcpu->arch.guest_fpu, guest_xsave->region, kvm_caps.supported_xcr0, -- 2.34.1

2 1

[PATCH OLK-6.6] x86/fpu: Clear XSTATE_BV[i] in guest XSAVE state whenever XFD[i]=1
by Zhang Kunbo 28 Jan '26

28 Jan '26

From: Sean Christopherson <seanjc(a)google.com> stable inclusion from stable-v6.12.67 commit f577508cc8a0adb8b4ebe9480bba7683b6149930 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/13516 CVE: CVE-2026-23005 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id… -------------------------------- commit b45f721775947a84996deb5c661602254ce25ce6 upstream. When loading guest XSAVE state via KVM_SET_XSAVE, and when updating XFD in response to a guest WRMSR, clear XFD-disabled features in the saved (or to be restored) XSTATE_BV to ensure KVM doesn't attempt to load state for features that are disabled via the guest's XFD. Because the kernel executes XRSTOR with the guest's XFD, saving XSTATE_BV[i]=1 with XFD[i]=1 will cause XRSTOR to #NM and panic the kernel. E.g. if fpu_update_guest_xfd() sets XFD without clearing XSTATE_BV: ------------[ cut here ]------------ WARNING: arch/x86/kernel/traps.c:1524 at exc_device_not_available+0x101/0x110, CPU#29: amx_test/848 Modules linked in: kvm_intel kvm irqbypass CPU: 29 UID: 1000 PID: 848 Comm: amx_test Not tainted 6.19.0-rc2-ffa07f7fd437-x86_amx_nm_xfd_non_init-vm #171 NONE Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 RIP: 0010:exc_device_not_available+0x101/0x110 Call Trace: <TASK> asm_exc_device_not_available+0x1a/0x20 RIP: 0010:restore_fpregs_from_fpstate+0x36/0x90 switch_fpu_return+0x4a/0xb0 kvm_arch_vcpu_ioctl_run+0x1245/0x1e40 [kvm] kvm_vcpu_ioctl+0x2c3/0x8f0 [kvm] __x64_sys_ioctl+0x8f/0xd0 do_syscall_64+0x62/0x940 entry_SYSCALL_64_after_hwframe+0x4b/0x53 </TASK> ---[ end trace 0000000000000000 ]--- This can happen if the guest executes WRMSR(MSR_IA32_XFD) to set XFD[18] = 1, and a host IRQ triggers kernel_fpu_begin() prior to the vmexit handler's call to fpu_update_guest_xfd(). and if userspace stuffs XSTATE_BV[i]=1 via KVM_SET_XSAVE: ------------[ cut here ]------------ WARNING: arch/x86/kernel/traps.c:1524 at exc_device_not_available+0x101/0x110, CPU#14: amx_test/867 Modules linked in: kvm_intel kvm irqbypass CPU: 14 UID: 1000 PID: 867 Comm: amx_test Not tainted 6.19.0-rc2-2dace9faccd6-x86_amx_nm_xfd_non_init-vm #168 NONE Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 RIP: 0010:exc_device_not_available+0x101/0x110 Call Trace: <TASK> asm_exc_device_not_available+0x1a/0x20 RIP: 0010:restore_fpregs_from_fpstate+0x36/0x90 fpu_swap_kvm_fpstate+0x6b/0x120 kvm_load_guest_fpu+0x30/0x80 [kvm] kvm_arch_vcpu_ioctl_run+0x85/0x1e40 [kvm] kvm_vcpu_ioctl+0x2c3/0x8f0 [kvm] __x64_sys_ioctl+0x8f/0xd0 do_syscall_64+0x62/0x940 entry_SYSCALL_64_after_hwframe+0x4b/0x53 </TASK> ---[ end trace 0000000000000000 ]--- The new behavior is consistent with the AMX architecture. Per Intel's SDM, XSAVE saves XSTATE_BV as '0' for components that are disabled via XFD (and non-compacted XSAVE saves the initial configuration of the state component): If XSAVE, XSAVEC, XSAVEOPT, or XSAVES is saving the state component i, the instruction does not generate #NM when XCR0[i] = IA32_XFD[i] = 1; instead, it operates as if XINUSE[i] = 0 (and the state component was in its initial state): it saves bit i of XSTATE_BV field of the XSAVE header as 0; in addition, XSAVE saves the initial configuration of the state component (the other instructions do not save state component i). Alternatively, KVM could always do XRSTOR with XFD=0, e.g. by using a constant XFD based on the set of enabled features when XSAVEing for a struct fpu_guest. However, having XSTATE_BV[i]=1 for XFD-disabled features can only happen in the above interrupt case, or in similar scenarios involving preemption on preemptible kernels, because fpu_swap_kvm_fpstate()'s call to save_fpregs_to_fpstate() saves the outgoing FPU state with the current XFD; and that is (on all but the first WRMSR to XFD) the guest XFD. Therefore, XFD can only go out of sync with XSTATE_BV in the above interrupt case, or in similar scenarios involving preemption on preemptible kernels, and it we can consider it (de facto) part of KVM ABI that KVM_GET_XSAVE returns XSTATE_BV[i]=0 for XFD-disabled features. Reported-by: Paolo Bonzini <pbonzini(a)redhat.com> Cc: stable(a)vger.kernel.org Fixes: 820a6ee944e7 ("kvm: x86: Add emulation for IA32_XFD", 2022-01-14) Signed-off-by: Sean Christopherson <seanjc(a)google.com> [Move clearing of XSTATE_BV from fpu_copy_uabi_to_guest_fpstate to kvm_vcpu_ioctl_x86_set_xsave. - Paolo] Reviewed-by: Binbin Wu <binbin.wu(a)linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini(a)redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Conflicts: arch/x86/kvm/x86.c [Context difference. ] Signed-off-by: Zhang Kunbo <zhangkunbo(a)huawei.com> --- arch/x86/kernel/fpu/core.c | 32 +++++++++++++++++++++++++++++--- arch/x86/kvm/x86.c | 9 +++++++++ 2 files changed, 38 insertions(+), 3 deletions(-) diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c index 1f0871be9d53..fd53ff26cd42 100644 --- a/arch/x86/kernel/fpu/core.c +++ b/arch/x86/kernel/fpu/core.c @@ -296,10 +296,29 @@ EXPORT_SYMBOL_GPL(fpu_enable_guest_xfd_features); #ifdef CONFIG_X86_64 void fpu_update_guest_xfd(struct fpu_guest *guest_fpu, u64 xfd) { + struct fpstate *fpstate = guest_fpu->fpstate; + fpregs_lock(); - guest_fpu->fpstate->xfd = xfd; - if (guest_fpu->fpstate->in_use) - xfd_update_state(guest_fpu->fpstate); + + /* + * KVM's guest ABI is that setting XFD[i]=1 *can* immediately revert the + * save state to its initial configuration. Likewise, KVM_GET_XSAVE does + * the same as XSAVE and returns XSTATE_BV[i]=0 whenever XFD[i]=1. + * + * If the guest's FPU state is in hardware, just update XFD: the XSAVE + * in fpu_swap_kvm_fpstate will clear XSTATE_BV[i] whenever XFD[i]=1. + * + * If however the guest's FPU state is NOT resident in hardware, clear + * disabled components in XSTATE_BV now, or a subsequent XRSTOR will + * attempt to load disabled components and generate #NM _in the host_. + */ + if (xfd && test_thread_flag(TIF_NEED_FPU_LOAD)) + fpstate->regs.xsave.header.xfeatures &= ~xfd; + + fpstate->xfd = xfd; + if (fpstate->in_use) + xfd_update_state(fpstate); + fpregs_unlock(); } EXPORT_SYMBOL_GPL(fpu_update_guest_xfd); @@ -407,6 +426,13 @@ int fpu_copy_uabi_to_guest_fpstate(struct fpu_guest *gfpu, const void *buf, if (ustate->xsave.header.xfeatures & ~xcr0) return -EINVAL; + /* + * Disabled features must be in their initial state, otherwise XRSTOR + * causes an exception. + */ + if (WARN_ON_ONCE(ustate->xsave.header.xfeatures & kstate->xfd)) + return -EINVAL; + /* * Nullify @vpkru to preserve its current value if PKRU's bit isn't set * in the header. KVM's odd ABI is to leave PKRU untouched in this diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 2139f728aecc..57fc6916906b 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -5541,9 +5541,18 @@ static void kvm_vcpu_ioctl_x86_get_xsave(struct kvm_vcpu *vcpu, static int kvm_vcpu_ioctl_x86_set_xsave(struct kvm_vcpu *vcpu, struct kvm_xsave *guest_xsave) { + union fpregs_state *xstate = (union fpregs_state *)guest_xsave->region; + if (fpstate_is_confidential(&vcpu->arch.guest_fpu)) return 0; + /* + * For backwards compatibility, do not expect disabled features to be in + * their initial state. XSTATE_BV[i] must still be cleared whenever + * XFD[i]=1, or XRSTOR would cause a #NM. + */ + xstate->xsave.header.xfeatures &= ~vcpu->arch.guest_fpu.fpstate->xfd; + return fpu_copy_uabi_to_guest_fpstate(&vcpu->arch.guest_fpu, guest_xsave->region, kvm_caps.supported_xcr0, -- 2.34.1

2 1

[PATCH v11 00/14] arm64: entry: Convert to Generic Entry
by Jinjie Ruan 28 Jan '26

28 Jan '26

Currently, x86, Riscv, Loongarch use the Generic Entry which makes maintainers' work easier and codes more elegant. arm64 has already successfully switched to the Generic IRQ Entry in commit b3cf07851b6c ("arm64: entry: Switch to generic IRQ entry"), it is time to completely convert arm64 to Generic Entry. The goal is to bring arm64 in line with other architectures that already use the generic entry infrastructure, reducing duplicated code and making it easier to share future changes in entry/exit paths, such as "Syscall User Dispatch". This patch set is rebased on arm64 (for-next/entry). And the performance was measured on Kunpeng 920 using "perf bench basic syscall" with "arm64.nopauth selinux=0 audit=1". After switch to Generic Entry, the performance are below: | Metric | W/O Generic Framework | With Generic Framework | Change | | ---------- | --------------------- | ---------------------- | ------ | | Total time | 2.487 [sec] | 2.393[sec] | ↓3.8% | | usecs/op | 0.248780 | 0.239361 | ↓3.8% | | ops/sec | 4,019,620 | 4,177,789 | ↑3.9% | Compared to earlier with arch specific handling, the performance improved by approximately 3.9%. On the basis of optimizing syscall_get_arguments()[1], el0_svc_common() and syscall_exit_work(), the performance are below: | Metric | W/O Generic Entry | With Generic Entry opt| Change | | ---------- | ----------------- | ------------------ | ------ | | Total time | 2.487 [sec] | 2.264 [sec] | ↓9.0% | | usecs/op | 0.248780 | 0.226481 | ↓9.0% | | ops/sec | 4,019,620 | 4,415,383 | ↑9.8% | Therefore, after the optimization, ARM64 System Call performance improved by approximately 9%. It was tested ok with following test cases on kunpeng920 and QEMU virt platform: - Perf tests. - Different `dynamic preempt` mode switch. - Pseudo NMI tests. - Stress-ng CPU stress test. - Hackbench stress test. - MTE test case in Documentation/arch/arm64/memory-tagging-extension.rst and all test cases in tools/testing/selftests/arm64/mte/*. - "sud" selftest testcase. - get_set_sud, get_syscall_info, set_syscall_info, peeksiginfo in tools/testing/selftests/ptrace. - breakpoint_test_arm64 in selftests/breakpoints. - syscall-abi and ptrace in tools/testing/selftests/arm64/abi - fp-ptrace, sve-ptrace, za-ptrace in selftests/arm64/fp. - vdso_test_getrandom in tools/testing/selftests/vDSO - Strace tests. The test QEMU configuration is as follows: qemu-system-aarch64 \ -M virt,gic-version=3,virtualization=on,mte=on \ -cpu max,pauth-impdef=on \ -kernel Image \ -smp 8,sockets=1,cores=4,threads=2 \ -m 512m \ -nographic \ -no-reboot \ -device virtio-rng-pci \ -append "root=/dev/vda rw console=ttyAMA0 kgdboc=ttyAMA0,115200 \ earlycon preempt=voluntary irqchip.gicv3_pseudo_nmi=1" \ -drive if=none,file=images/rootfs.ext4,format=raw,id=hd0 \ -device virtio-blk-device,drive=hd0 \ [1]: https://kernel.googlesource.com/pub/scm/linux/kernel/git/akpm/mm/+/89bf683c… Changes in v11: - Remove unused syscall in syscall_trace_enter(). - Update and provide a detailed explanation of the differences after moving rseq_syscall() before audit_syscall_exit(). - Rebased on arm64 (for-next/entry), and remove the first applied 3 patchs. - syscall_exit_to_user_mode_work() for arch reuse instead of adding new syscall_exit_to_user_mode_work_prepare() helper. - Link to v10: https://lore.kernel.org/all/20251222114737.1334364-1-ruanjinjie@huawei.com/ Changes in v10: - Rebased on v6.19-rc1, rename syscall_exit_to_user_mode_prepare() to syscall_exit_to_user_mode_work_prepare() to avoid conflict. - Also inline syscall_trace_enter(). - Support aarch64 for sud_benchmark. - Update and correct the commit message. - Add Reviewed-by. - Link to v9: https://lore.kernel.org/all/20251204082123.2792067-1-ruanjinjie@huawei.com/ Changes in v9: - Move "Return early for ptrace_report_syscall_entry() error" patch ahead to make it not introduce a regression. - Not check _TIF_SECCOMP/SYSCALL_EMU for syscall_exit_work() in a separate patch. - Do not report_syscall_exit() for PTRACE_SYSEMU_SINGLESTEP in a separate patch. - Add two performance patch to improve the arm64 performance. - Add Reviewed-by. - Link to v8: https://lore.kernel.org/all/20251126071446.3234218-1-ruanjinjie@huawei.com/ Changes in v8: - Rename "report_syscall_enter()" to "report_syscall_entry()". - Add ptrace_save_reg() to avoid duplication. - Remove unused _TIF_WORK_MASK in a standalone patch. - Align syscall_trace_enter() return value with the generic version. - Use "scno" instead of regs->syscallno in el0_svc_common(). - Move rseq_syscall() ahead in a standalone patch to clarify it clearly. - Rename "syscall_trace_exit()" to "syscall_exit_work()". - Keep the goto in el0_svc_common(). - No argument was passed to __secure_computing() and check -1 not -1L. - Remove "Add has_syscall_work() helper" patch. - Move "Add syscall_exit_to_user_mode_prepare() helper" patch later. - Add miss header for asm/entry-common.h. - Update the implementation of arch_syscall_is_vdso_sigreturn(). - Add "ARCH_SYSCALL_WORK_EXIT" to be defined as "SECCOMP | SYSCALL_EMU" to keep the behaviour unchanged. - Add more testcases test. - Add Reviewed-by. - Update the commit message. - Link to v7: https://lore.kernel.org/all/20251117133048.53182-1-ruanjinjie@huawei.com/ Chanegs in v7: - Support "Syscall User Dispatch" by implementing arch_syscall_is_vdso_sigreturn() as kemal suggested. - Add aarch64 support for "sud" selftest testcase, which tested ok with the patch series. - Fix the kernel test robot warning for arch_ptrace_report_syscall_entry() and arch_ptrace_report_syscall_exit() in asm/entry-common.h. - Add perf syscall performance test. - Link to v6: https://lore.kernel.org/all/20250916082611.2972008-1-ruanjinjie@huawei.com/ Changes in v6: - Rebased on v6.17-rc5-next as arm64 generic irq entry has merged. - Update the commit message. - Link to v5: https://lore.kernel.org/all/20241206101744.4161990-1-ruanjinjie@huawei.com/ Changes in v5: - Not change arm32 and keep inerrupts_enabled() macro for gicv3 driver. - Move irqentry_state definition into arch/arm64/kernel/entry-common.c. - Avoid removing the __enter_from_*() and __exit_to_*() wrappers. - Update "irqentry_state_t ret/irq_state" to "state" to keep it consistently. - Use generic irq entry header for PREEMPT_DYNAMIC after split the generic entry. - Also refactor the ARM64 syscall code. - Introduce arch_ptrace_report_syscall_entry/exit(), instead of arch_pre/post_report_syscall_entry/exit() to simplify code. - Make the syscall patches clear separation. - Update the commit message. - Link to v4: https://lore.kernel.org/all/20241025100700.3714552-1-ruanjinjie@huawei.com/ Changes in v4: - Rework/cleanup split into a few patches as Mark suggested. - Replace interrupts_enabled() macro with regs_irqs_disabled(), instead of left it here. - Remove rcu and lockdep state in pt_regs by using temporary irqentry_state_t as Mark suggested. - Remove some unnecessary intermediate functions to make it clear. - Rework preempt irq and PREEMPT_DYNAMIC code to make the switch more clear. - arch_prepare_*_entry/exit() -> arch_pre_*_entry/exit(). - Expand the arch functions comment. - Make arch functions closer to its caller. - Declare saved_reg in for block. - Remove arch_exit_to_kernel_mode_prepare(), arch_enter_from_kernel_mode(). - Adjust "Add few arch functions to use generic entry" patch to be the penultimate. - Update the commit message. - Add suggested-by. - Link to v3: https://lore.kernel.org/all/20240629085601.470241-1-ruanjinjie@huawei.com/ Changes in v3: - Test the MTE test cases. - Handle forget_syscall() in arch_post_report_syscall_entry() - Make the arch funcs not use __weak as Thomas suggested, so move the arch funcs to entry-common.h, and make arch_forget_syscall() folded in arch_post_report_syscall_entry() as suggested. - Move report_single_step() to thread_info.h for arm64 - Change __always_inline() to inline, add inline for the other arch funcs. - Remove unused signal.h for entry-common.h. - Add Suggested-by. - Update the commit message. Changes in v2: - Add tested-by. - Fix a bug that not call arch_post_report_syscall_entry() in syscall_trace_enter() if ptrace_report_syscall_entry() return not zero. - Refactor report_syscall(). - Add comment for arch_prepare_report_syscall_exit(). - Adjust entry-common.h header file inclusion to alphabetical order. - Update the commit message. Jinjie Ruan (13): entry: Remove unused syscall in syscall_trace_enter() arm64/ptrace: Refactor syscall_trace_enter/exit() arm64: ptrace: Move rseq_syscall() before audit_syscall_exit() arm64: syscall: Rework el0_svc_common() arm64/ptrace: Not check _TIF_SECCOMP/SYSCALL_EMU for syscall_exit_work() arm64/ptrace: Do not report_syscall_exit() for PTRACE_SYSEMU_SINGLESTEP arm64/ptrace: Expand secure_computing() in place arm64/ptrace: Use syscall_get_arguments() helper entry: Rework syscall_exit_to_user_mode_work() for arch reuse entry: Add arch_ptrace_report_syscall_entry/exit() arm64: entry: Convert to generic entry arm64: Inline el0_svc_common() entry: Inline syscall_exit_work() and syscall_trace_enter() kemal (1): selftests: sud_test: Support aarch64 arch/arm64/Kconfig | 2 +- arch/arm64/include/asm/entry-common.h | 76 +++++++++ arch/arm64/include/asm/syscall.h | 19 ++- arch/arm64/include/asm/thread_info.h | 16 +- arch/arm64/kernel/debug-monitors.c | 7 + arch/arm64/kernel/ptrace.c | 115 ------------- arch/arm64/kernel/signal.c | 2 +- arch/arm64/kernel/syscall.c | 29 +--- include/linux/entry-common.h | 158 ++++++++++++++++-- kernel/entry/common.h | 7 - kernel/entry/syscall-common.c | 96 +---------- kernel/entry/syscall_user_dispatch.c | 4 +- .../syscall_user_dispatch/sud_benchmark.c | 2 +- .../syscall_user_dispatch/sud_test.c | 4 + 14 files changed, 268 insertions(+), 269 deletions(-) delete mode 100644 kernel/entry/common.h -- 2.34.1

1 14

[PATCH OLK-6.6 0/2] Fix exception when umount with release dev fd
by Hongbo Li 28 Jan '26

28 Jan '26

Fix exception when umount with release dev fd. Hongbo Li (2): mfs: Fix wild-memory-access error when mfs event is destroy. mfs: Do not release the async event immediately when read failed fs/mfs/cache.c | 2 ++ fs/mfs/dev.c | 12 ++++++++---- fs/mfs/super.c | 6 +++++- 3 files changed, 15 insertions(+), 5 deletions(-) -- 2.34.1

2 3

[PATCH OLK-6.6] tracing: Fix crash on synthetic stacktrace field usage
by Tengda Wu 28 Jan '26

28 Jan '26

From: Steven Rostedt <rostedt(a)goodmis.org> mainline inclusion from mainline-v6.19-rc4 commit 90f9f5d64cae4e72defd96a2a22760173cb3c9ec category: bugfix bugzilla: https://atomgit.com/openeuler/kernel/issues/8435 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?… -------------------------------- When creating a synthetic event based on an existing synthetic event that had a stacktrace field and the new synthetic event used that field a kernel crash occurred: ~# cd /sys/kernel/tracing ~# echo 's:stack unsigned long stack[];' > dynamic_events ~# echo 'hist:keys=prev_pid:s0=common_stacktrace if prev_state & 3' >> events/sched/sched_switch/trigger ~# echo 'hist:keys=next_pid:s1=$s0:onmatch(sched.sched_switch).trace(stack,$s1)' >> events/sched/sched_switch/trigger The above creates a synthetic event that takes a stacktrace when a task schedules out in a non-running state and passes that stacktrace to the sched_switch event when that task schedules back in. It triggers the "stack" synthetic event that has a stacktrace as its field (called "stack"). ~# echo 's:syscall_stack s64 id; unsigned long stack[];' >> dynamic_events ~# echo 'hist:keys=common_pid:s2=stack' >> events/synthetic/stack/trigger ~# echo 'hist:keys=common_pid:s3=$s2,i0=id:onmatch(synthetic.stack).trace(syscall_stack,$i0,$s3)' >> events/raw_syscalls/sys_exit/trigger The above makes another synthetic event called "syscall_stack" that attaches the first synthetic event (stack) to the sys_exit trace event and records the stacktrace from the stack event with the id of the system call that is exiting. When enabling this event (or using it in a historgram): ~# echo 1 > events/synthetic/syscall_stack/enable Produces a kernel crash! BUG: unable to handle page fault for address: 0000000000400010 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: Oops: 0000 [#1] SMP PTI CPU: 6 UID: 0 PID: 1257 Comm: bash Not tainted 6.16.3+deb14-amd64 #1 PREEMPT(lazy) Debian 6.16.3-1 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.17.0-debian-1.17.0-1 04/01/2014 RIP: 0010:trace_event_raw_event_synth+0x90/0x380 Code: c5 00 00 00 00 85 d2 0f 84 e1 00 00 00 31 db eb 34 0f 1f 00 66 66 2e 0f 1f 84 00 00 00 00 00 66 66 2e 0f 1f 84 00 00 00 00 00 <49> 8b 04 24 48 83 c3 01 8d 0c c5 08 00 00 00 01 cd 41 3b 5d 40 0f RSP: 0018:ffffd2670388f958 EFLAGS: 00010202 RAX: ffff8ba1065cc100 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000001 RSI: fffff266ffda7b90 RDI: ffffd2670388f9b0 RBP: 0000000000000010 R08: ffff8ba104e76000 R09: ffffd2670388fa50 R10: ffff8ba102dd42e0 R11: ffffffff9a908970 R12: 0000000000400010 R13: ffff8ba10a246400 R14: ffff8ba10a710220 R15: fffff266ffda7b90 FS: 00007fa3bc63f740(0000) GS:ffff8ba2e0f48000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000400010 CR3: 0000000107f9e003 CR4: 0000000000172ef0 Call Trace: <TASK> ? __tracing_map_insert+0x208/0x3a0 action_trace+0x67/0x70 event_hist_trigger+0x633/0x6d0 event_triggers_call+0x82/0x130 trace_event_buffer_commit+0x19d/0x250 trace_event_raw_event_sys_exit+0x62/0xb0 syscall_exit_work+0x9d/0x140 do_syscall_64+0x20a/0x2f0 ? trace_event_raw_event_sched_switch+0x12b/0x170 ? save_fpregs_to_fpstate+0x3e/0x90 ? _raw_spin_unlock+0xe/0x30 ? finish_task_switch.isra.0+0x97/0x2c0 ? __rseq_handle_notify_resume+0xad/0x4c0 ? __schedule+0x4b8/0xd00 ? restore_fpregs_from_fpstate+0x3c/0x90 ? switch_fpu_return+0x5b/0xe0 ? do_syscall_64+0x1ef/0x2f0 ? do_fault+0x2e9/0x540 ? __handle_mm_fault+0x7d1/0xf70 ? count_memcg_events+0x167/0x1d0 ? handle_mm_fault+0x1d7/0x2e0 ? do_user_addr_fault+0x2c3/0x7f0 entry_SYSCALL_64_after_hwframe+0x76/0x7e The reason is that the stacktrace field is not labeled as such, and is treated as a normal field and not as a dynamic event that it is. In trace_event_raw_event_synth() the event is field is still treated as a dynamic array, but the retrieval of the data is considered a normal field, and the reference is just the meta data: // Meta data is retrieved instead of a dynamic array str_val = (char *)(long)var_ref_vals[val_idx]; // Then when it tries to process it: len = *((unsigned long *)str_val) + 1; It triggers a kernel page fault. To fix this, first when defining the fields of the first synthetic event, set the filter type to FILTER_STACKTRACE. This is used later by the second synthetic event to know that this field is a stacktrace. When creating the field of the new synthetic event, have it use this FILTER_STACKTRACE to know to create a stacktrace field to copy the stacktrace into. Cc: stable(a)vger.kernel.org Cc: Masami Hiramatsu <mhiramat(a)kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers(a)efficios.com> Cc: Tom Zanussi <zanussi(a)kernel.org> Link: https://patch.msgid.link/20260122194824.6905a38e@gandalf.local.home Fixes: 00cf3d672a9d ("tracing: Allow synthetic events to pass around stacktraces") Signed-off-by: Steven Rostedt (Google) <rostedt(a)goodmis.org> Signed-off-by: Tengda Wu <wutengda2(a)huawei.com> --- kernel/trace/trace_events_hist.c | 9 +++++++++ kernel/trace/trace_events_synth.c | 8 +++++++- 2 files changed, 16 insertions(+), 1 deletion(-) diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c index 2d6f3c63bc62..f22aa4afaa6d 100644 --- a/kernel/trace/trace_events_hist.c +++ b/kernel/trace/trace_events_hist.c @@ -2047,6 +2047,15 @@ static struct hist_field *create_hist_field(struct hist_trigger_data *hist_data, hist_field->fn_num = HIST_FIELD_FN_RELDYNSTRING; else hist_field->fn_num = HIST_FIELD_FN_PSTRING; + } else if (field->filter_type == FILTER_STACKTRACE) { + flags |= HIST_FIELD_FL_STACKTRACE; + + hist_field->size = MAX_FILTER_STR_VAL; + hist_field->type = kstrdup_const(field->type, GFP_KERNEL); + if (!hist_field->type) + goto free; + + hist_field->fn_num = HIST_FIELD_FN_STACK; } else { hist_field->size = field->size; hist_field->is_signed = field->is_signed; diff --git a/kernel/trace/trace_events_synth.c b/kernel/trace/trace_events_synth.c index 794e72dbb12d..13c2d3ad7185 100644 --- a/kernel/trace/trace_events_synth.c +++ b/kernel/trace/trace_events_synth.c @@ -137,7 +137,9 @@ static int synth_event_define_fields(struct trace_event_call *call) struct synth_event *event = call->data; unsigned int i, size, n_u64; char *name, *type; + int filter_type; bool is_signed; + bool is_stack; int ret = 0; for (i = 0, n_u64 = 0; i < event->n_fields; i++) { @@ -145,8 +147,12 @@ static int synth_event_define_fields(struct trace_event_call *call) is_signed = event->fields[i]->is_signed; type = event->fields[i]->type; name = event->fields[i]->name; + is_stack = event->fields[i]->is_stack; + + filter_type = is_stack ? FILTER_STACKTRACE : FILTER_OTHER; + ret = trace_define_field(call, type, name, offset, size, - is_signed, FILTER_OTHER); + is_signed, filter_type); if (ret) break; -- 2.34.1

2 1

[PATCH OLK-6.6] ima: don't clear IMA_DIGSIG flag when setting or removing non-IMA xattr
by Zhao Yipeng 27 Jan '26

27 Jan '26

From: Coiby Xu <coxu(a)redhat.com> stable inclusion from stable-v6.6.117 commit d2993a7e98eb70c737c6f5365a190e79c72b8407 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/11626 CVE: CVE-2025-68183 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id… -------------------------------- [ Upstream commit 88b4cbcf6b041ae0f2fc8a34554a5b6a83a2b7cd ] Currently when both IMA and EVM are in fix mode, the IMA signature will be reset to IMA hash if a program first stores IMA signature in security.ima and then writes/removes some other security xattr for the file. For example, on Fedora, after booting the kernel with "ima_appraise=fix evm=fix ima_policy=appraise_tcb" and installing rpm-plugin-ima, installing/reinstalling a package will not make good reference IMA signature generated. Instead IMA hash is generated, # getfattr -m - -d -e hex /usr/bin/bash # file: usr/bin/bash security.ima=0x0404... This happens because when setting security.selinux, the IMA_DIGSIG flag that had been set early was cleared. As a result, IMA hash is generated when the file is closed. Similarly, IMA signature can be cleared on file close after removing security xattr like security.evm or setting/removing ACL. Prevent replacing the IMA file signature with a file hash, by preventing the IMA_DIGSIG flag from being reset. Here's a minimal C reproducer which sets security.selinux as the last step which can also replaced by removing security.evm or setting ACL, #include <stdio.h> #include <sys/xattr.h> #include <fcntl.h> #include <unistd.h> #include <string.h> #include <stdlib.h> int main() { const char* file_path = "/usr/sbin/test_binary"; const char* hex_string = "030204d33204490066306402304"; int length = strlen(hex_string); char* ima_attr_value; int fd; fd = open(file_path, O_WRONLY|O_CREAT|O_EXCL, 0644); if (fd == -1) { perror("Error opening file"); return 1; } ima_attr_value = (char*)malloc(length / 2 ); for (int i = 0, j = 0; i < length; i += 2, j++) { sscanf(hex_string + i, "%2hhx", &ima_attr_value[j]); } if (fsetxattr(fd, "security.ima", ima_attr_value, length/2, 0) == -1) { perror("Error setting extended attribute"); close(fd); return 1; } const char* selinux_value= "system_u:object_r:bin_t:s0"; if (fsetxattr(fd, "security.selinux", selinux_value, strlen(selinux_value), 0) == -1) { perror("Error setting extended attribute"); close(fd); return 1; } close(fd); return 0; } Signed-off-by: Coiby Xu <coxu(a)redhat.com> Signed-off-by: Mimi Zohar <zohar(a)linux.ibm.com> Signed-off-by: Sasha Levin <sashal(a)kernel.org> Signed-off-by: Zhao Yipeng <zhaoyipeng5(a)huawei.com> --- security/integrity/ima/ima_appraise.c | 23 ++++++++++++++++++----- 1 file changed, 18 insertions(+), 5 deletions(-) diff --git a/security/integrity/ima/ima_appraise.c b/security/integrity/ima/ima_appraise.c index 8a54399d212d..a9e31d8addc6 100644 --- a/security/integrity/ima/ima_appraise.c +++ b/security/integrity/ima/ima_appraise.c @@ -809,6 +809,15 @@ static int ima_protect_xattr(struct dentry *dentry, const char *xattr_name, return 0; } +/* + * ima_reset_appraise_flags - reset ima_iint_cache flags + * + * @digsig: whether to clear/set IMA_DIGSIG flag, tristate values + * 0: clear IMA_DIGSIG + * 1: set IMA_DIGSIG + * -1: don't change IMA_DIGSIG + * + */ static void ima_reset_appraise_flags(struct inode *inode, int digsig) { struct integrity_iint_cache *iint; @@ -821,9 +830,9 @@ static void ima_reset_appraise_flags(struct inode *inode, int digsig) return; iint->measured_pcrs = 0; set_bit(IMA_CHANGE_XATTR, &iint->atomic_flags); - if (digsig) + if (digsig == 1) set_bit(IMA_DIGSIG, &iint->atomic_flags); - else + else if (digsig == 0) clear_bit(IMA_DIGSIG, &iint->atomic_flags); } @@ -908,6 +917,8 @@ int ima_inode_setxattr(struct dentry *dentry, const char *xattr_name, digsig = (xvalue->type == EVM_IMA_XATTR_DIGSIG); } else if (!strcmp(xattr_name, XATTR_NAME_EVM) && xattr_value_len > 0) { digsig = (xvalue->type == EVM_XATTR_PORTABLE_DIGSIG); + } else { + digsig = -1; } if (result == 1 || evm_revalidate_status(xattr_name)) { ima_reset_appraise_flags(d_backing_inode(dentry), digsig); @@ -921,18 +932,20 @@ int ima_inode_set_acl(struct mnt_idmap *idmap, struct dentry *dentry, const char *acl_name, struct posix_acl *kacl) { if (evm_revalidate_status(acl_name)) - ima_reset_appraise_flags(d_backing_inode(dentry), 0); + ima_reset_appraise_flags(d_backing_inode(dentry), -1); return 0; } int ima_inode_removexattr(struct dentry *dentry, const char *xattr_name) { - int result; + int result, digsig = -1; result = ima_protect_xattr(dentry, xattr_name, NULL, 0); if (result == 1 || evm_revalidate_status(xattr_name)) { - ima_reset_appraise_flags(d_backing_inode(dentry), 0); + if (!strcmp(xattr_name, XATTR_NAME_IMA)) + digsig = 0; + ima_reset_appraise_flags(d_backing_inode(dentry), digsig); if (result == 1) result = 0; } -- 2.34.1

2 1

[PATCH OLK-5.10] wifi: prevent A-MSDU attacks in mesh networks
by Zhang Yuwei 27 Jan '26

27 Jan '26

From: Mathy Vanhoef <Mathy.Vanhoef(a)kuleuven.be> stable inclusion from stable-v6.1.146 commit e2c8a3c0388aef6bfc4aabfba07bc7dff16eea80 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/7758 CVE: CVE-2025-27558 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id… -------------------------------- commit 737bb912ebbe4571195c56eba557c4d7315b26fb upstream. This patch is a mitigation to prevent the A-MSDU spoofing vulnerability for mesh networks. The initial update to the IEEE 802.11 standard, in response to the FragAttacks, missed this case (CVE-2025-27558). It can be considered a variant of CVE-2020-24588 but for mesh networks. This patch tries to detect if a standard MSDU was turned into an A-MSDU by an adversary. This is done by parsing a received A-MSDU as a standard MSDU, calculating the length of the Mesh Control header, and seeing if the 6 bytes after this header equal the start of an rfc1042 header. If equal, this is a strong indication of an ongoing attack attempt. This defense was tested with mac80211_hwsim against a mesh network that uses an empty Mesh Address Extension field, i.e., when four addresses are used, and when using a 12-byte Mesh Address Extension field, i.e., when six addresses are used. Functionality of normal MSDUs and A-MSDUs was also tested, and confirmed working, when using both an empty and 12-byte Mesh Address Extension field. It was also tested with mac80211_hwsim that A-MSDU attacks in non-mesh networks keep being detected and prevented. Note that the vulnerability being patched, and the defense being implemented, was also discussed in the following paper and in the following IEEE 802.11 presentation: https://papers.mathyvanhoef.com/wisec2025.pdf https://mentor.ieee.org/802.11/dcn/25/11-25-0949-00-000m-a-msdu-mesh-spoof-… Cc: stable(a)vger.kernel.org Signed-off-by: Mathy Vanhoef <Mathy.Vanhoef(a)kuleuven.be> Link: https://patch.msgid.link/20250616004635.224344-1-Mathy.Vanhoef@kuleuven.be Signed-off-by: Johannes Berg <johannes.berg(a)intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Conflicts: net/wireless/util.c [Fanhua Li: context conflict] Signed-off-by: Fanhua Li <lifanhua5(a)huawei.com> --- net/wireless/util.c | 51 +++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 49 insertions(+), 2 deletions(-) diff --git a/net/wireless/util.c b/net/wireless/util.c index 15773db362a1..81ac8d1da085 100644 --- a/net/wireless/util.c +++ b/net/wireless/util.c @@ -742,6 +742,51 @@ __ieee80211_amsdu_copy(struct sk_buff *skb, unsigned int hlen, return frame; } +/* + * Detects if an MSDU frame was maliciously converted into an A-MSDU + * frame by an adversary. This is done by parsing the received frame + * as if it were a regular MSDU, even though the A-MSDU flag is set. + * + * For non-mesh interfaces, detection involves checking whether the + * payload, when interpreted as an MSDU, begins with a valid RFC1042 + * header. This is done by comparing the A-MSDU subheader's destination + * address to the start of the RFC1042 header. + * + * For mesh interfaces, the MSDU includes a 6-byte Mesh Control field + * and an optional variable-length Mesh Address Extension field before + * the RFC1042 header. The position of the RFC1042 header must therefore + * be calculated based on the mesh header length. + * + * Since this function intentionally parses an A-MSDU frame as an MSDU, + * it only assumes that the A-MSDU subframe header is present, and + * beyond this it performs its own bounds checks under the assumption + * that the frame is instead parsed as a non-aggregated MSDU. + */ +static bool +is_amsdu_aggregation_attack(struct ethhdr *eth, struct sk_buff *skb, + enum nl80211_iftype iftype) +{ + int offset; + + /* Non-mesh case can be directly compared */ + if (iftype != NL80211_IFTYPE_MESH_POINT) + return ether_addr_equal(eth->h_dest, rfc1042_header); + + offset = __ieee80211_get_mesh_hdrlen(eth->h_dest[0]); + if (offset == 6) { + /* Mesh case with empty address extension field */ + return ether_addr_equal(eth->h_source, rfc1042_header); + } else if (offset + ETH_ALEN <= skb->len) { + /* Mesh case with non-empty address extension field */ + u8 temp[ETH_ALEN]; + + skb_copy_bits(skb, offset, temp, ETH_ALEN); + return ether_addr_equal(temp, rfc1042_header); + } + + return false; +} + void ieee80211_amsdu_to_8023s(struct sk_buff *skb, struct sk_buff_head *list, const u8 *addr, enum nl80211_iftype iftype, const unsigned int extra_headroom, @@ -774,8 +819,10 @@ void ieee80211_amsdu_to_8023s(struct sk_buff *skb, struct sk_buff_head *list, /* the last MSDU has no padding */ if (subframe_len > remaining) goto purge; - /* mitigate A-MSDU aggregation injection attacks */ - if (ether_addr_equal(eth.h_dest, rfc1042_header)) + /* mitigate A-MSDU aggregation injection attacks, to be + * checked when processing first subframe (offset == 0). + */ + if (offset == 0 && is_amsdu_aggregation_attack(&eth, skb, iftype)) goto purge; offset += sizeof(struct ethhdr); -- 2.22.0

2 1

[PATCH OLK-6.6] wifi: prevent A-MSDU attacks in mesh networks
by Zhang Yuwei 27 Jan '26

27 Jan '26

From: Mathy Vanhoef <Mathy.Vanhoef(a)kuleuven.be> stable inclusion from stable-v6.6.99 commit ec6392061de6681148b63ee6c8744da833498cdd category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/7758 CVE: CVE-2025-27558 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id… -------------------------------- commit 737bb912ebbe4571195c56eba557c4d7315b26fb upstream. This patch is a mitigation to prevent the A-MSDU spoofing vulnerability for mesh networks. The initial update to the IEEE 802.11 standard, in response to the FragAttacks, missed this case (CVE-2025-27558). It can be considered a variant of CVE-2020-24588 but for mesh networks. This patch tries to detect if a standard MSDU was turned into an A-MSDU by an adversary. This is done by parsing a received A-MSDU as a standard MSDU, calculating the length of the Mesh Control header, and seeing if the 6 bytes after this header equal the start of an rfc1042 header. If equal, this is a strong indication of an ongoing attack attempt. This defense was tested with mac80211_hwsim against a mesh network that uses an empty Mesh Address Extension field, i.e., when four addresses are used, and when using a 12-byte Mesh Address Extension field, i.e., when six addresses are used. Functionality of normal MSDUs and A-MSDUs was also tested, and confirmed working, when using both an empty and 12-byte Mesh Address Extension field. It was also tested with mac80211_hwsim that A-MSDU attacks in non-mesh networks keep being detected and prevented. Note that the vulnerability being patched, and the defense being implemented, was also discussed in the following paper and in the following IEEE 802.11 presentation: https://papers.mathyvanhoef.com/wisec2025.pdf https://mentor.ieee.org/802.11/dcn/25/11-25-0949-00-000m-a-msdu-mesh-spoof-… Cc: stable(a)vger.kernel.org Signed-off-by: Mathy Vanhoef <Mathy.Vanhoef(a)kuleuven.be> Link: https://patch.msgid.link/20250616004635.224344-1-Mathy.Vanhoef@kuleuven.be Signed-off-by: Johannes Berg <johannes.berg(a)intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Signed-off-by: Wang Hai <wanghai38(a)huawei.com> --- net/wireless/util.c | 52 +++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 50 insertions(+), 2 deletions(-) diff --git a/net/wireless/util.c b/net/wireless/util.c index 7acd8d0db61a..24e5af65da58 100644 --- a/net/wireless/util.c +++ b/net/wireless/util.c @@ -826,6 +826,52 @@ bool ieee80211_is_valid_amsdu(struct sk_buff *skb, u8 mesh_hdr) } EXPORT_SYMBOL(ieee80211_is_valid_amsdu); + +/* + * Detects if an MSDU frame was maliciously converted into an A-MSDU + * frame by an adversary. This is done by parsing the received frame + * as if it were a regular MSDU, even though the A-MSDU flag is set. + * + * For non-mesh interfaces, detection involves checking whether the + * payload, when interpreted as an MSDU, begins with a valid RFC1042 + * header. This is done by comparing the A-MSDU subheader's destination + * address to the start of the RFC1042 header. + * + * For mesh interfaces, the MSDU includes a 6-byte Mesh Control field + * and an optional variable-length Mesh Address Extension field before + * the RFC1042 header. The position of the RFC1042 header must therefore + * be calculated based on the mesh header length. + * + * Since this function intentionally parses an A-MSDU frame as an MSDU, + * it only assumes that the A-MSDU subframe header is present, and + * beyond this it performs its own bounds checks under the assumption + * that the frame is instead parsed as a non-aggregated MSDU. + */ +static bool +is_amsdu_aggregation_attack(struct ethhdr *eth, struct sk_buff *skb, + enum nl80211_iftype iftype) +{ + int offset; + + /* Non-mesh case can be directly compared */ + if (iftype != NL80211_IFTYPE_MESH_POINT) + return ether_addr_equal(eth->h_dest, rfc1042_header); + + offset = __ieee80211_get_mesh_hdrlen(eth->h_dest[0]); + if (offset == 6) { + /* Mesh case with empty address extension field */ + return ether_addr_equal(eth->h_source, rfc1042_header); + } else if (offset + ETH_ALEN <= skb->len) { + /* Mesh case with non-empty address extension field */ + u8 temp[ETH_ALEN]; + + skb_copy_bits(skb, offset, temp, ETH_ALEN); + return ether_addr_equal(temp, rfc1042_header); + } + + return false; +} + void ieee80211_amsdu_to_8023s(struct sk_buff *skb, struct sk_buff_head *list, const u8 *addr, enum nl80211_iftype iftype, const unsigned int extra_headroom, @@ -867,8 +913,10 @@ void ieee80211_amsdu_to_8023s(struct sk_buff *skb, struct sk_buff_head *list, /* the last MSDU has no padding */ if (subframe_len > remaining) goto purge; - /* mitigate A-MSDU aggregation injection attacks */ - if (ether_addr_equal(hdr.eth.h_dest, rfc1042_header)) + /* mitigate A-MSDU aggregation injection attacks, to be + * checked when processing first subframe (offset == 0). + */ + if (offset == 0 && is_amsdu_aggregation_attack(&hdr.eth, skb, iftype)) goto purge; offset += sizeof(struct ethhdr); -- 2.22.0

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[PATCH OLK-5.10] wifi: prevent A-MSDU attacks in mesh networks
by Fanhua Li 27 Jan '26

27 Jan '26

From: Mathy Vanhoef <Mathy.Vanhoef(a)kuleuven.be> stable inclusion from stable-v6.1.146 commit e2c8a3c0388aef6bfc4aabfba07bc7dff16eea80 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/9288 CVE: CVE-2025-38512 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id… -------------------------------- commit 737bb912ebbe4571195c56eba557c4d7315b26fb upstream. This patch is a mitigation to prevent the A-MSDU spoofing vulnerability for mesh networks. The initial update to the IEEE 802.11 standard, in response to the FragAttacks, missed this case (CVE-2025-27558). It can be considered a variant of CVE-2020-24588 but for mesh networks. This patch tries to detect if a standard MSDU was turned into an A-MSDU by an adversary. This is done by parsing a received A-MSDU as a standard MSDU, calculating the length of the Mesh Control header, and seeing if the 6 bytes after this header equal the start of an rfc1042 header. If equal, this is a strong indication of an ongoing attack attempt. This defense was tested with mac80211_hwsim against a mesh network that uses an empty Mesh Address Extension field, i.e., when four addresses are used, and when using a 12-byte Mesh Address Extension field, i.e., when six addresses are used. Functionality of normal MSDUs and A-MSDUs was also tested, and confirmed working, when using both an empty and 12-byte Mesh Address Extension field. It was also tested with mac80211_hwsim that A-MSDU attacks in non-mesh networks keep being detected and prevented. Note that the vulnerability being patched, and the defense being implemented, was also discussed in the following paper and in the following IEEE 802.11 presentation: https://papers.mathyvanhoef.com/wisec2025.pdf https://mentor.ieee.org/802.11/dcn/25/11-25-0949-00-000m-a-msdu-mesh-spoof-… Cc: stable(a)vger.kernel.org Signed-off-by: Mathy Vanhoef <Mathy.Vanhoef(a)kuleuven.be> Link: https://patch.msgid.link/20250616004635.224344-1-Mathy.Vanhoef@kuleuven.be Signed-off-by: Johannes Berg <johannes.berg(a)intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Conflicts: net/wireless/util.c [Fanhua Li: context conflict] Signed-off-by: Fanhua Li <lifanhua5(a)huawei.com> --- net/wireless/util.c | 51 +++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 49 insertions(+), 2 deletions(-) diff --git a/net/wireless/util.c b/net/wireless/util.c index 15773db362a15..81ac8d1da0854 100644 --- a/net/wireless/util.c +++ b/net/wireless/util.c @@ -742,6 +742,51 @@ __ieee80211_amsdu_copy(struct sk_buff *skb, unsigned int hlen, return frame; } +/* + * Detects if an MSDU frame was maliciously converted into an A-MSDU + * frame by an adversary. This is done by parsing the received frame + * as if it were a regular MSDU, even though the A-MSDU flag is set. + * + * For non-mesh interfaces, detection involves checking whether the + * payload, when interpreted as an MSDU, begins with a valid RFC1042 + * header. This is done by comparing the A-MSDU subheader's destination + * address to the start of the RFC1042 header. + * + * For mesh interfaces, the MSDU includes a 6-byte Mesh Control field + * and an optional variable-length Mesh Address Extension field before + * the RFC1042 header. The position of the RFC1042 header must therefore + * be calculated based on the mesh header length. + * + * Since this function intentionally parses an A-MSDU frame as an MSDU, + * it only assumes that the A-MSDU subframe header is present, and + * beyond this it performs its own bounds checks under the assumption + * that the frame is instead parsed as a non-aggregated MSDU. + */ +static bool +is_amsdu_aggregation_attack(struct ethhdr *eth, struct sk_buff *skb, + enum nl80211_iftype iftype) +{ + int offset; + + /* Non-mesh case can be directly compared */ + if (iftype != NL80211_IFTYPE_MESH_POINT) + return ether_addr_equal(eth->h_dest, rfc1042_header); + + offset = __ieee80211_get_mesh_hdrlen(eth->h_dest[0]); + if (offset == 6) { + /* Mesh case with empty address extension field */ + return ether_addr_equal(eth->h_source, rfc1042_header); + } else if (offset + ETH_ALEN <= skb->len) { + /* Mesh case with non-empty address extension field */ + u8 temp[ETH_ALEN]; + + skb_copy_bits(skb, offset, temp, ETH_ALEN); + return ether_addr_equal(temp, rfc1042_header); + } + + return false; +} + void ieee80211_amsdu_to_8023s(struct sk_buff *skb, struct sk_buff_head *list, const u8 *addr, enum nl80211_iftype iftype, const unsigned int extra_headroom, @@ -774,8 +819,10 @@ void ieee80211_amsdu_to_8023s(struct sk_buff *skb, struct sk_buff_head *list, /* the last MSDU has no padding */ if (subframe_len > remaining) goto purge; - /* mitigate A-MSDU aggregation injection attacks */ - if (ether_addr_equal(eth.h_dest, rfc1042_header)) + /* mitigate A-MSDU aggregation injection attacks, to be + * checked when processing first subframe (offset == 0). + */ + if (offset == 0 && is_amsdu_aggregation_attack(&eth, skb, iftype)) goto purge; offset += sizeof(struct ethhdr); -- 2.43.0

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[PATCH OLK-5.10] mlxsw: spectrum_router: Fix neighbour use-after-free
by Cai Xinchen 27 Jan '26

27 Jan '26

From: Ido Schimmel <idosch(a)nvidia.com> stable inclusion from stable-v5.10.248 commit a2dfe6758fc63e542105bee8b17a3a7485684db0 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/13354 CVE: CVE-2025-68801 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id… -------------------------------- [ Upstream commit 8b0e69763ef948fb872a7767df4be665d18f5fd4 ] We sometimes observe use-after-free when dereferencing a neighbour [1]. The problem seems to be that the driver stores a pointer to the neighbour, but without holding a reference on it. A reference is only taken when the neighbour is used by a nexthop. Fix by simplifying the reference counting scheme. Always take a reference when storing a neighbour pointer in a neighbour entry. Avoid taking a referencing when the neighbour is used by a nexthop as the neighbour entry associated with the nexthop already holds a reference. Tested by running the test that uncovered the problem over 300 times. Without this patch the problem was reproduced after a handful of iterations. [1] BUG: KASAN: slab-use-after-free in mlxsw_sp_neigh_entry_update+0x2d4/0x310 Read of size 8 at addr ffff88817f8e3420 by task ip/3929 CPU: 3 UID: 0 PID: 3929 Comm: ip Not tainted 6.18.0-rc4-virtme-g36b21a067510 #3 PREEMPT(full) Hardware name: Nvidia SN5600/VMOD0013, BIOS 5.13 05/31/2023 Call Trace: <TASK> dump_stack_lvl+0x6f/0xa0 print_address_description.constprop.0+0x6e/0x300 print_report+0xfc/0x1fb kasan_report+0xe4/0x110 mlxsw_sp_neigh_entry_update+0x2d4/0x310 mlxsw_sp_router_rif_gone_sync+0x35f/0x510 mlxsw_sp_rif_destroy+0x1ea/0x730 mlxsw_sp_inetaddr_port_vlan_event+0xa1/0x1b0 __mlxsw_sp_inetaddr_lag_event+0xcc/0x130 __mlxsw_sp_inetaddr_event+0xf5/0x3c0 mlxsw_sp_router_netdevice_event+0x1015/0x1580 notifier_call_chain+0xcc/0x150 call_netdevice_notifiers_info+0x7e/0x100 __netdev_upper_dev_unlink+0x10b/0x210 netdev_upper_dev_unlink+0x79/0xa0 vrf_del_slave+0x18/0x50 do_set_master+0x146/0x7d0 do_setlink.isra.0+0x9a0/0x2880 rtnl_newlink+0x637/0xb20 rtnetlink_rcv_msg+0x6fe/0xb90 netlink_rcv_skb+0x123/0x380 netlink_unicast+0x4a3/0x770 netlink_sendmsg+0x75b/0xc90 __sock_sendmsg+0xbe/0x160 ____sys_sendmsg+0x5b2/0x7d0 ___sys_sendmsg+0xfd/0x180 __sys_sendmsg+0x124/0x1c0 do_syscall_64+0xbb/0xfd0 entry_SYSCALL_64_after_hwframe+0x4b/0x53 [...] Allocated by task 109: kasan_save_stack+0x30/0x50 kasan_save_track+0x14/0x30 __kasan_kmalloc+0x7b/0x90 __kmalloc_noprof+0x2c1/0x790 neigh_alloc+0x6af/0x8f0 ___neigh_create+0x63/0xe90 mlxsw_sp_nexthop_neigh_init+0x430/0x7e0 mlxsw_sp_nexthop_type_init+0x212/0x960 mlxsw_sp_nexthop6_group_info_init.constprop.0+0x81f/0x1280 mlxsw_sp_nexthop6_group_get+0x392/0x6a0 mlxsw_sp_fib6_entry_create+0x46a/0xfd0 mlxsw_sp_router_fib6_replace+0x1ed/0x5f0 mlxsw_sp_router_fib6_event_work+0x10a/0x2a0 process_one_work+0xd57/0x1390 worker_thread+0x4d6/0xd40 kthread+0x355/0x5b0 ret_from_fork+0x1d4/0x270 ret_from_fork_asm+0x11/0x20 Freed by task 154: kasan_save_stack+0x30/0x50 kasan_save_track+0x14/0x30 __kasan_save_free_info+0x3b/0x60 __kasan_slab_free+0x43/0x70 kmem_cache_free_bulk.part.0+0x1eb/0x5e0 kvfree_rcu_bulk+0x1f2/0x260 kfree_rcu_work+0x130/0x1b0 process_one_work+0xd57/0x1390 worker_thread+0x4d6/0xd40 kthread+0x355/0x5b0 ret_from_fork+0x1d4/0x270 ret_from_fork_asm+0x11/0x20 Last potentially related work creation: kasan_save_stack+0x30/0x50 kasan_record_aux_stack+0x8c/0xa0 kvfree_call_rcu+0x93/0x5b0 mlxsw_sp_router_neigh_event_work+0x67d/0x860 process_one_work+0xd57/0x1390 worker_thread+0x4d6/0xd40 kthread+0x355/0x5b0 ret_from_fork+0x1d4/0x270 ret_from_fork_asm+0x11/0x20 Fixes: 6cf3c971dc84 ("mlxsw: spectrum_router: Add private neigh table") Signed-off-by: Ido Schimmel <idosch(a)nvidia.com> Reviewed-by: Petr Machata <petrm(a)nvidia.com> Signed-off-by: Petr Machata <petrm(a)nvidia.com> Reviewed-by: Simon Horman <horms(a)kernel.org> Link: https://patch.msgid.link/92d75e21d95d163a41b5cea67a15cd33f547cba6.176469565… Signed-off-by: Jakub Kicinski <kuba(a)kernel.org> Signed-off-by: Sasha Levin <sashal(a)kernel.org> Signed-off-by: Cai Xinchen <caixinchen1(a)huawei.com> --- .../ethernet/mellanox/mlxsw/spectrum_router.c | 17 +++++++++-------- 1 file changed, 9 insertions(+), 8 deletions(-) diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c index d2887ae508bb..e22ee1336d74 100644 --- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c +++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c @@ -2032,6 +2032,7 @@ mlxsw_sp_neigh_entry_alloc(struct mlxsw_sp *mlxsw_sp, struct neighbour *n, if (!neigh_entry) return NULL; + neigh_hold(n); neigh_entry->key.n = n; neigh_entry->rif = rif; INIT_LIST_HEAD(&neigh_entry->nexthop_list); @@ -2041,6 +2042,7 @@ mlxsw_sp_neigh_entry_alloc(struct mlxsw_sp *mlxsw_sp, struct neighbour *n, static void mlxsw_sp_neigh_entry_free(struct mlxsw_sp_neigh_entry *neigh_entry) { + neigh_release(neigh_entry->key.n); kfree(neigh_entry); } @@ -3607,6 +3609,8 @@ mlxsw_sp_nexthop_dead_neigh_replace(struct mlxsw_sp *mlxsw_sp, if (err) goto err_neigh_entry_insert; + neigh_release(old_n); + read_lock_bh(&n->lock); nud_state = n->nud_state; dead = n->dead; @@ -3615,14 +3619,10 @@ mlxsw_sp_nexthop_dead_neigh_replace(struct mlxsw_sp *mlxsw_sp, list_for_each_entry(nh, &neigh_entry->nexthop_list, neigh_list_node) { - neigh_release(old_n); - neigh_clone(n); __mlxsw_sp_nexthop_neigh_update(nh, !entry_connected); mlxsw_sp_nexthop_group_refresh(mlxsw_sp, nh->nh_grp); } - neigh_release(n); - return 0; err_neigh_entry_insert: @@ -3711,6 +3711,11 @@ static int mlxsw_sp_nexthop_neigh_init(struct mlxsw_sp *mlxsw_sp, } } + /* Release the reference taken by neigh_lookup() / neigh_create() since + * neigh_entry already holds one. + */ + neigh_release(n); + /* If that is the first nexthop connected to that neigh, add to * nexthop_neighs_list */ @@ -3737,11 +3742,9 @@ static void mlxsw_sp_nexthop_neigh_fini(struct mlxsw_sp *mlxsw_sp, struct mlxsw_sp_nexthop *nh) { struct mlxsw_sp_neigh_entry *neigh_entry = nh->neigh_entry; - struct neighbour *n; if (!neigh_entry) return; - n = neigh_entry->key.n; __mlxsw_sp_nexthop_neigh_update(nh, true); list_del(&nh->neigh_list_node); @@ -3755,8 +3758,6 @@ static void mlxsw_sp_nexthop_neigh_fini(struct mlxsw_sp *mlxsw_sp, if (!neigh_entry->connected && list_empty(&neigh_entry->nexthop_list)) mlxsw_sp_neigh_entry_destroy(mlxsw_sp, neigh_entry); - - neigh_release(n); } static bool mlxsw_sp_ipip_netdev_ul_up(struct net_device *ol_dev) -- 2.34.1

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