From 9849d1dfef022eaab8bc60a0643c57de912c599e Mon Sep 17 00:00:00 2001 From: Brett Mastbergen Date: Tue, 9 Sep 2025 10:38:01 -0400 Subject: [PATCH 1/4] posix-cpu-timers: fix race between handle_posix_cpu_timers() and posix_cpu_timer_del() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit jira VULN-136688 cve CVE-2025-38352 commit-author Oleg Nesterov commit f90fff1e152dedf52b932240ebbd670d83330eca upstream-diff Used 5.4 LT 78a4b8e3795b31dae58762bc091bb0f4f74a2200 version If an exiting non-autoreaping task has already passed exit_notify() and calls handle_posix_cpu_timers() from IRQ, it can be reaped by its parent or debugger right after unlock_task_sighand(). If a concurrent posix_cpu_timer_del() runs at that moment, it won't be able to detect timer->it.cpu.firing != 0: cpu_timer_task_rcu() and/or lock_task_sighand() will fail. Add the tsk->exit_state check into run_posix_cpu_timers() to fix this. This fix is not needed if CONFIG_POSIX_CPU_TIMERS_TASK_WORK=y, because exit_task_work() is called before exit_notify(). But the check still makes sense, task_work_add(&tsk->posix_cputimers_work.work) will fail anyway in this case. Cc: stable@vger.kernel.org Reported-by: Benoît Sevens Fixes: 0bdd2ed4138e ("sched: run_posix_cpu_timers: Don't check ->exit_state, use lock_task_sighand()") Signed-off-by: Oleg Nesterov Signed-off-by: Linus Torvalds (cherry picked from commit f90fff1e152dedf52b932240ebbd670d83330eca) Signed-off-by: Brett Mastbergen --- kernel/time/posix-cpu-timers.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/kernel/time/posix-cpu-timers.c b/kernel/time/posix-cpu-timers.c index bd856eee9ba46..ffe1f0bfd8675 100644 --- a/kernel/time/posix-cpu-timers.c +++ b/kernel/time/posix-cpu-timers.c @@ -1122,6 +1122,15 @@ void run_posix_cpu_timers(void) lockdep_assert_irqs_disabled(); + /* + * Ensure that release_task(tsk) can't happen while + * handle_posix_cpu_timers() is running. Otherwise, a concurrent + * posix_cpu_timer_del() may fail to lock_task_sighand(tsk) and + * miss timer->it.cpu.firing != 0. + */ + if (tsk->exit_state) + return; + /* * The fast path checks that there are no expired thread or thread * group timers. If that's so, just return. From 372a456700a339d3f7536535fe4effacc8404b50 Mon Sep 17 00:00:00 2001 From: Brett Mastbergen Date: Tue, 9 Sep 2025 10:44:26 -0400 Subject: [PATCH 2/4] devlink: Fix use-after-free after a failed reload jira VULN-3798 cve CVE-2022-3625 commit-author Ido Schimmel commit 6b4db2e528f650c7fb712961aac36455468d5902 After a failed devlink reload, devlink parameters are still registered, which means user space can set and get their values. In the case of the mlxsw "acl_region_rehash_interval" parameter, these operations will trigger a use-after-free [1]. Fix this by rejecting set and get operations while in the failed state. Return the "-EOPNOTSUPP" error code which does not abort the parameters dump, but instead causes it to skip over the problematic parameter. Another possible fix is to perform these checks in the mlxsw parameter callbacks, but other drivers might be affected by the same problem and I am not aware of scenarios where these stricter checks will cause a regression. [1] mlxsw_spectrum3 0000:00:10.0: Port 125: Failed to register netdev mlxsw_spectrum3 0000:00:10.0: Failed to create ports ================================================================== BUG: KASAN: use-after-free in mlxsw_sp_acl_tcam_vregion_rehash_intrvl_get+0xbd/0xd0 drivers/net/ethernet/mellanox/mlxsw/spectrum_acl_tcam.c:904 Read of size 4 at addr ffff8880099dcfd8 by task kworker/u4:4/777 CPU: 1 PID: 777 Comm: kworker/u4:4 Not tainted 5.19.0-rc7-custom-126601-gfe26f28c586d #1 Hardware name: QEMU MSN4700, BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014 Workqueue: netns cleanup_net Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x92/0xbd lib/dump_stack.c:106 print_address_description mm/kasan/report.c:313 [inline] print_report.cold+0x5e/0x5cf mm/kasan/report.c:429 kasan_report+0xb9/0xf0 mm/kasan/report.c:491 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report_generic.c:306 mlxsw_sp_acl_tcam_vregion_rehash_intrvl_get+0xbd/0xd0 drivers/net/ethernet/mellanox/mlxsw/spectrum_acl_tcam.c:904 mlxsw_sp_acl_region_rehash_intrvl_get+0x49/0x60 drivers/net/ethernet/mellanox/mlxsw/spectrum_acl.c:1106 mlxsw_sp_params_acl_region_rehash_intrvl_get+0x33/0x80 drivers/net/ethernet/mellanox/mlxsw/spectrum.c:3854 devlink_param_get net/core/devlink.c:4981 [inline] devlink_nl_param_fill+0x238/0x12d0 net/core/devlink.c:5089 devlink_param_notify+0xe5/0x230 net/core/devlink.c:5168 devlink_ns_change_notify net/core/devlink.c:4417 [inline] devlink_ns_change_notify net/core/devlink.c:4396 [inline] devlink_reload+0x15f/0x700 net/core/devlink.c:4507 devlink_pernet_pre_exit+0x112/0x1d0 net/core/devlink.c:12272 ops_pre_exit_list net/core/net_namespace.c:152 [inline] cleanup_net+0x494/0xc00 net/core/net_namespace.c:582 process_one_work+0x9fc/0x1710 kernel/workqueue.c:2289 worker_thread+0x675/0x10b0 kernel/workqueue.c:2436 kthread+0x30c/0x3d0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306 The buggy address belongs to the physical page: page:ffffea0000267700 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x99dc flags: 0x100000000000000(node=0|zone=1) raw: 0100000000000000 0000000000000000 dead000000000122 0000000000000000 raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880099dce80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff8880099dcf00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff >ffff8880099dcf80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ^ ffff8880099dd000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff8880099dd080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ================================================================== Fixes: 98bbf70c1c41 ("mlxsw: spectrum: add "acl_region_rehash_interval" devlink param") Signed-off-by: Ido Schimmel Reviewed-by: Jiri Pirko Signed-off-by: David S. Miller (cherry picked from commit 6b4db2e528f650c7fb712961aac36455468d5902) Signed-off-by: Brett Mastbergen --- net/core/devlink.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/net/core/devlink.c b/net/core/devlink.c index 4fbee9024c131..89c08394f1ae4 100644 --- a/net/core/devlink.c +++ b/net/core/devlink.c @@ -4353,7 +4353,7 @@ static int devlink_param_get(struct devlink *devlink, const struct devlink_param *param, struct devlink_param_gset_ctx *ctx) { - if (!param->get) + if (!param->get || devlink->reload_failed) return -EOPNOTSUPP; return param->get(devlink, param->id, ctx); } @@ -4362,7 +4362,7 @@ static int devlink_param_set(struct devlink *devlink, const struct devlink_param *param, struct devlink_param_gset_ctx *ctx) { - if (!param->set) + if (!param->set || devlink->reload_failed) return -EOPNOTSUPP; return param->set(devlink, param->id, ctx); } From 9cea3c94ec89a6681ce69691f6625e96646a676b Mon Sep 17 00:00:00 2001 From: Brett Mastbergen Date: Tue, 9 Sep 2025 10:48:39 -0400 Subject: [PATCH 3/4] KVM: x86: do not report a vCPU as preempted outside instruction boundaries jira VULN-3802 cve CVE-2022-39189 commit-author Paolo Bonzini commit 6cd88243c7e03845a450795e134b488fc2afb736 If a vCPU is outside guest mode and is scheduled out, it might be in the process of making a memory access. A problem occurs if another vCPU uses the PV TLB flush feature during the period when the vCPU is scheduled out, and a virtual address has already been translated but has not yet been accessed, because this is equivalent to using a stale TLB entry. To avoid this, only report a vCPU as preempted if sure that the guest is at an instruction boundary. A rescheduling request will be delivered to the host physical CPU as an external interrupt, so for simplicity consider any vmexit *not* instruction boundary except for external interrupts. It would in principle be okay to report the vCPU as preempted also if it is sleeping in kvm_vcpu_block(): a TLB flush IPI will incur the vmentry/vmexit overhead unnecessarily, and optimistic spinning is also unlikely to succeed. However, leave it for later because right now kvm_vcpu_check_block() is doing memory accesses. Even though the TLB flush issue only applies to virtual memory address, it's very much preferrable to be conservative. Reported-by: Jann Horn Signed-off-by: Paolo Bonzini (cherry picked from commit 6cd88243c7e03845a450795e134b488fc2afb736) Signed-off-by: Brett Mastbergen --- arch/x86/include/asm/kvm_host.h | 3 +++ arch/x86/kvm/svm/svm.c | 2 ++ arch/x86/kvm/vmx/vmx.c | 1 + arch/x86/kvm/x86.c | 22 ++++++++++++++++++++++ 4 files changed, 28 insertions(+) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index c108053d930b9..8085bb6e11c6e 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -639,6 +639,7 @@ struct kvm_vcpu_arch { u64 ia32_misc_enable_msr; u64 smbase; u64 smi_count; + bool at_instruction_boundary; bool tpr_access_reporting; bool xsaves_enabled; bool xfd_no_write_intercept; @@ -1256,6 +1257,8 @@ struct kvm_vcpu_stat { u64 nested_run; u64 directed_yield_attempted; u64 directed_yield_successful; + u64 preemption_reported; + u64 preemption_other; u64 guest_mode; }; diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index 520738227587f..b994fdab10820 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -4255,6 +4255,8 @@ static int svm_check_intercept(struct kvm_vcpu *vcpu, static void svm_handle_exit_irqoff(struct kvm_vcpu *vcpu) { + if (to_svm(vcpu)->vmcb->control.exit_code == SVM_EXIT_INTR) + vcpu->arch.at_instruction_boundary = true; } static void svm_sched_in(struct kvm_vcpu *vcpu, int cpu) diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index 0a8a11a3e0f96..f6e908936366d 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -6521,6 +6521,7 @@ static void handle_external_interrupt_irqoff(struct kvm_vcpu *vcpu) return; handle_interrupt_nmi_irqoff(vcpu, gate_offset(desc)); + vcpu->arch.at_instruction_boundary = true; } static void vmx_handle_exit_irqoff(struct kvm_vcpu *vcpu) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index b92821f209fa1..4bffb4d329305 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -278,6 +278,8 @@ const struct _kvm_stats_desc kvm_vcpu_stats_desc[] = { STATS_DESC_COUNTER(VCPU, nested_run), STATS_DESC_COUNTER(VCPU, directed_yield_attempted), STATS_DESC_COUNTER(VCPU, directed_yield_successful), + STATS_DESC_COUNTER(VCPU, preemption_reported), + STATS_DESC_COUNTER(VCPU, preemption_other), STATS_DESC_ICOUNTER(VCPU, guest_mode) }; @@ -4462,6 +4464,19 @@ static void kvm_steal_time_set_preempted(struct kvm_vcpu *vcpu) struct kvm_host_map map; struct kvm_steal_time *st; + /* + * The vCPU can be marked preempted if and only if the VM-Exit was on + * an instruction boundary and will not trigger guest emulation of any + * kind (see vcpu_run). Vendor specific code controls (conservatively) + * when this is true, for example allowing the vCPU to be marked + * preempted if and only if the VM-Exit was due to a host interrupt. + */ + if (!vcpu->arch.at_instruction_boundary) { + vcpu->stat.preemption_other++; + return; + } + + vcpu->stat.preemption_reported++; if (!(vcpu->arch.st.msr_val & KVM_MSR_ENABLED)) return; @@ -10040,6 +10055,13 @@ static int vcpu_run(struct kvm_vcpu *vcpu) vcpu->arch.l1tf_flush_l1d = true; for (;;) { + /* + * If another guest vCPU requests a PV TLB flush in the middle + * of instruction emulation, the rest of the emulation could + * use a stale page translation. Assume that any code after + * this point can start executing an instruction. + */ + vcpu->arch.at_instruction_boundary = false; if (kvm_vcpu_running(vcpu)) { r = vcpu_enter_guest(vcpu); } else { From ad7c1e339c050204ad2307d817a7ac015d70d45e Mon Sep 17 00:00:00 2001 From: Brett Mastbergen Date: Tue, 9 Sep 2025 10:51:31 -0400 Subject: [PATCH 4/4] wifi: cfg80211: fix u8 overflow in cfg80211_update_notlisted_nontrans() jira VULN-3805 cve CVE-2022-41674 commit-author Johannes Berg commit aebe9f4639b13a1f4e9a6b42cdd2e38c617b442d In the copy code of the elements, we do the following calculation to reach the end of the MBSSID element: /* copy the IEs after MBSSID */ cpy_len = mbssid[1] + 2; This looks fine, however, cpy_len is a u8, the same as mbssid[1], so the addition of two can overflow. In this case the subsequent memcpy() will overflow the allocated buffer, since it copies 256 bytes too much due to the way the allocation and memcpy() sizes are calculated. Fix this by using size_t for the cpy_len variable. This fixes CVE-2022-41674. Reported-by: Soenke Huster Tested-by: Soenke Huster Fixes: 0b8fb8235be8 ("cfg80211: Parsing of Multiple BSSID information in scanning") Reviewed-by: Kees Cook Signed-off-by: Johannes Berg (cherry picked from commit aebe9f4639b13a1f4e9a6b42cdd2e38c617b442d) Signed-off-by: Brett Mastbergen --- net/wireless/scan.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/wireless/scan.c b/net/wireless/scan.c index 22e92be619388..4abc971b5df39 100644 --- a/net/wireless/scan.c +++ b/net/wireless/scan.c @@ -2240,7 +2240,7 @@ cfg80211_update_notlisted_nontrans(struct wiphy *wiphy, size_t new_ie_len; struct cfg80211_bss_ies *new_ies; const struct cfg80211_bss_ies *old; - u8 cpy_len; + size_t cpy_len; lockdep_assert_held(&wiphy_to_rdev(wiphy)->bss_lock);