Linux Kernel

In the Linux kernel, the following vulnerability has been resolved: bpf: Fix deadlock when freeing cgroup storage The following commit bc235cdb423a ("bpf: Prevent deadlock from recursive bpf_task_storage_[get|delete]") first introduced deadlock prevention for fentry/fexit programs attaching on bpf_task_storage helpers. That commit also employed the logic in map free path in its v6 version. Later bpf_cgrp_storage was first introduced in c4bcfb38a95e ("bpf: Implement cgroup storage available to non-cgroup-attached bpf progs") which faces the same issue as bpf_task_storage, instead of its busy counter, NULL was passed to bpf_local_storage_map_free() which opened a window to cause deadlock: <TASK> (acquiring local_storage->lock) _raw_spin_lock_irqsave+0x3d/0x50 bpf_local_storage_update+0xd1/0x460 bpf_cgrp_storage_get+0x109/0x130 bpf_prog_a4d4a370ba857314_cgrp_ptr+0x139/0x170 ? __bpf_prog_enter_recur+0x16/0x80 bpf_trampoline_6442485186+0x43/0xa4 cgroup_storage_ptr+0x9/0x20 (holding local_storage->lock) bpf_selem_unlink_storage_nolock.constprop.0+0x135/0x160 bpf_selem_unlink_storage+0x6f/0x110 bpf_local_storage_map_free+0xa2/0x110 bpf_map_free_deferred+0x5b/0x90 process_one_work+0x17c/0x390 worker_thread+0x251/0x360 kthread+0xd2/0x100 ret_from_fork+0x34/0x50 ret_from_fork_asm+0x1a/0x30 </TASK> Progs: - A: SEC("fentry/cgroup_storage_ptr") - cgid (BPF_MAP_TYPE_HASH) Record the id of the cgroup the current task belonging to in this hash map, using the address of the cgroup as the map key. - cgrpa (BPF_MAP_TYPE_CGRP_STORAGE) If current task is a kworker, lookup the above hash map using function parameter @owner as the key to get its corresponding cgroup id which is then used to get a trusted pointer to the cgroup through bpf_cgroup_from_id(). This trusted pointer can then be passed to bpf_cgrp_storage_get() to finally trigger the deadlock issue. - B: SEC("tp_btf/sys_enter") - cgrpb (BPF_MAP_TYPE_CGRP_STORAGE) The only purpose of this prog is to fill Prog A's hash map by calling bpf_cgrp_storage_get() for as many userspace tasks as possible. Steps to reproduce: - Run A; - while (true) { Run B; Destroy B; } Fix this issue by passing its busy counter to the free procedure so it can be properly incremented before storage/smap locking.Show less

In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix racy issue from session lookup and expire Increment the session reference count within the lock for lookup to avoid racy issue with session expire.Show less

In the Linux kernel, the following vulnerability has been resolved: drm/panthor: avoid garbage value in panthor_ioctl_dev_query() 'priorities_info' is uninitialized, and the uninitialized value is copied to user object when calling PANTHOR_UOBJ_SET(). Using memset to initialize 'priorities_info' to avoid this garbage value problem.Show less

In the Linux kernel, the following vulnerability has been resolved: amdkfd: properly free gang_ctx_bo when failed to init user queue The destructor of a gtt bo is declared as void amdgpu_amdkfd_free_gtt_mem(struct amdgpu_device *adev, void **mem_obj); Which takes void** as the second parameter. GCC allows passing void* to the function because void* can be implicitly casted to any other types, so it can pass compiling. However, passing this void* parameter into the function's execution process(which expects void** and dereferencing void**) will result in errors.Show less

In the Linux kernel, the following vulnerability has been resolved: cpufreq/amd-pstate: Fix cpufreq_policy ref counting amd_pstate_update_limits() takes a cpufreq_policy reference but doesn't decrement the refcount in one of the exit paths, fix that.Show less

In the Linux kernel, the following vulnerability has been resolved: thermal/netlink: Prevent userspace segmentation fault by adjusting UAPI header The intel-lpmd tool [1], which uses the THERMAL_GENL_ATTR_CPU_CAPABILITY attribute to receive HFI events from kernel space, encounters a segmentation fault after commit 1773572863c4 ("thermal: netlink: Add the commands and the events for the thresholds"). The issue arises because the THERMAL_GENL_ATTR_CPU_CAPABILITY raw value was changed while intel_lpmd still uses the old value. Although intel_lpmd can be updated to check the THERMAL_GENL_VERSION and use the appropriate THERMAL_GENL_ATTR_CPU_CAPABILITY value, the commit itself is questionable. The commit introduced a new element in the middle of enum thermal_genl_attr, which affects many existing attributes and introduces potential risks and unnecessary maintenance burdens for userspace thermal netlink event users. Solve the issue by moving the newly introduced THERMAL_GENL_ATTR_TZ_PREV_TEMP attribute to the end of the enum thermal_genl_attr. This ensures that all existing thermal generic netlink attributes remain unaffected. [ rjw: Subject edits ]Show less

In the Linux kernel, the following vulnerability has been resolved: KVM: x86: Load DR6 with guest value only before entering .vcpu_run() loop Move the conditional loading of hardware DR6 with the guest's DR6 value out of the core .vcpu_run() loop to fix a bug where KVM can load hardware with a stale vcpu->arch.dr6. When the guest accesses a DR and host userspace isn't debugging the guest, KVM disables DR interception and loads the guest's values into hardware on VM-Enter and saves them on VM-Exit. This allows the guest to access DRs at will, e.g. so that a sequence of DR accesses to configure a breakpoint only generates one VM-Exit. For DR0-DR3, the logic/behavior is identical between VMX and SVM, and also identical between KVM_DEBUGREG_BP_ENABLED (userspace debugging the guest) and KVM_DEBUGREG_WONT_EXIT (guest using DRs), and so KVM handles loading DR0-DR3 in common code, _outside_ of the core kvm_x86_ops.vcpu_run() loop. But for DR6, the guest's value doesn't need to be loaded into hardware for KVM_DEBUGREG_BP_ENABLED, and SVM provides a dedicated VMCB field whereas VMX requires software to manually load the guest value, and so loading the guest's value into DR6 is handled by {svm,vmx}_vcpu_run(), i.e. is done _inside_ the core run loop. Unfortunately, saving the guest values on VM-Exit is initiated by common x86, again outside of the core run loop. If the guest modifies DR6 (in hardware, when DR interception is disabled), and then the next VM-Exit is a fastpath VM-Exit, KVM will reload hardware DR6 with vcpu->arch.dr6 and clobber the guest's actual value. The bug shows up primarily with nested VMX because KVM handles the VMX preemption timer in the fastpath, and the window between hardware DR6 being modified (in guest context) and DR6 being read by guest software is orders of magnitude larger in a nested setup. E.g. in non-nested, the VMX preemption timer would need to fire precisely between #DB injection and the #DB handler's read of DR6, whereas with a KVM-on-KVM setup, the window where hardware DR6 is "dirty" extends all the way from L1 writing DR6 to VMRESUME (in L1). L1's view: ========== <L1 disables DR interception> CPU 0/KVM-7289 [023] d.... 2925.640961: kvm_entry: vcpu 0 A: L1 Writes DR6 CPU 0/KVM-7289 [023] d.... 2925.640963: <hack>: Set DRs, DR6 = 0xffff0ff1 B: CPU 0/KVM-7289 [023] d.... 2925.640967: kvm_exit: vcpu 0 reason EXTERNAL_INTERRUPT intr_info 0x800000ec D: L1 reads DR6, arch.dr6 = 0 CPU 0/KVM-7289 [023] d.... 2925.640969: <hack>: Sync DRs, DR6 = 0xffff0ff0 CPU 0/KVM-7289 [023] d.... 2925.640976: kvm_entry: vcpu 0 L2 reads DR6, L1 disables DR interception CPU 0/KVM-7289 [023] d.... 2925.640980: kvm_exit: vcpu 0 reason DR_ACCESS info1 0x0000000000000216 CPU 0/KVM-7289 [023] d.... 2925.640983: kvm_entry: vcpu 0 CPU 0/KVM-7289 [023] d.... 2925.640983: <hack>: Set DRs, DR6 = 0xffff0ff0 L2 detects failure CPU 0/KVM-7289 [023] d.... 2925.640987: kvm_exit: vcpu 0 reason HLT L1 reads DR6 (confirms failure) CPU 0/KVM-7289 [023] d.... 2925.640990: <hack>: Sync DRs, DR6 = 0xffff0ff0 L0's view: ========== L2 reads DR6, arch.dr6 = 0 CPU 23/KVM-5046 [001] d.... 3410.005610: kvm_exit: vcpu 23 reason DR_ACCESS info1 0x0000000000000216 CPU 23/KVM-5046 [001] ..... 3410.005610: kvm_nested_vmexit: vcpu 23 reason DR_ACCESS info1 0x0000000000000216 L2 => L1 nested VM-Exit CPU 23/KVM-5046 [001] ..... 3410.005610: kvm_nested_vmexit_inject: reason: DR_ACCESS ext_inf1: 0x0000000000000216 CPU 23/KVM-5046 [001] d.... 3410.005610: kvm_entry: vcpu 23 CPU 23/KVM-5046 [001] d.... 3410.005611: kvm_exit: vcpu 23 reason VMREAD CPU 23/KVM-5046 [001] d.... 3410.005611: kvm_entry: vcpu 23 CPU 23/KVM-5046 [001] d.... 3410. ---truncated---Show less

In the Linux kernel, the following vulnerability has been resolved: usb: gadget: core: flush gadget workqueue after device removal device_del() can lead to new work being scheduled in gadget->work workqueue. This is observed, for example, with the dwc3 driver with the following call stack: device_del() gadget_unbind_driver() usb_gadget_disconnect_locked() dwc3_gadget_pullup() dwc3_gadget_soft_disconnect() usb_gadget_set_state() schedule_work(&gadget->work) Move flush_work() after device_del() to ensure the workqueue is cleaned up.Show less

In the Linux kernel, the following vulnerability has been resolved: io_uring/kbuf: reallocate buf lists on upgrade IORING_REGISTER_PBUF_RING can reuse an old struct io_buffer_list if it was created for legacy selected buffer and has been emptied. It violates the requirement that most of the field should stay stable after publish. Always reallocate it instead.Show less

In the Linux kernel, the following vulnerability has been resolved: usb: gadget: f_midi: fix MIDI Streaming descriptor lengths While the MIDI jacks are configured correctly, and the MIDIStreaming endpoint descriptors are filled with the correct information, bNumEmbMIDIJack and bLength are set incorrectly in these descriptors. This does not matter when the numbers of in and out ports are equal, but when they differ the host will receive broken descriptors with uninitialized stack memory leaking into the descriptor for whichever value is smaller. The precise meaning of "in" and "out" in the port counts is not clearly defined and can be confusing. But elsewhere the driver consistently uses this to match the USB meaning of IN and OUT viewed from the host, so that "in" ports send data to the host and "out" ports receive data from it.Show less

In the Linux kernel, the following vulnerability has been resolved: seccomp: passthrough uretprobe systemcall without filtering When attaching uretprobes to processes running inside docker, the attached process is segfaulted when encountering the retprobe. The reason is that now that uretprobe is a system call the default seccomp filters in docker block it as they only allow a specific set of known syscalls. This is true for other userspace applications which use seccomp to control their syscall surface. Since uretprobe is a "kernel implementation detail" system call which is not used by userspace application code directly, it is impractical and there's very little point in forcing all userspace applications to explicitly allow it in order to avoid crashing tracked processes. Pass this systemcall through seccomp without depending on configuration. Note: uretprobe is currently only x86_64 and isn't expected to ever be supported in i386. [kees: minimized changes for easier backporting, tweaked commit log]Show less

In the Linux kernel, the following vulnerability has been resolved: iommu/vt-d: Avoid use of NULL after WARN_ON_ONCE There is a WARN_ON_ONCE to catch an unlikely situation when domain_remove_dev_pasid can't find the `pasid`. In case it nevertheless happens we must avoid using a NULL pointer.Show less

In the Linux kernel, the following vulnerability has been resolved: block: don't revert iter for -EIOCBQUEUED blkdev_read_iter() has a few odd checks, like gating the position and count adjustment on whether or not the result is bigger-than-or-equal to zero (where bigger than makes more sense), and not checking the return value of blkdev_direct_IO() before doing an iov_iter_revert(). The latter can lead to attempting to revert with a negative value, which when passed to iov_iter_revert() as an unsigned value will lead to throwing a WARN_ON() because unroll is bigger than MAX_RW_COUNT. Be sane and don't revert for -EIOCBQUEUED, like what is done in other spots.Show less

In the Linux kernel, the following vulnerability has been resolved: PCI: Avoid putting some root ports into D3 on TUXEDO Sirius Gen1 commit 9d26d3a8f1b0 ("PCI: Put PCIe ports into D3 during suspend") sets the policy that all PCIe ports are allowed to use D3. When the system is suspended if the port is not power manageable by the platform and won't be used for wakeup via a PME this sets up the policy for these ports to go into D3hot. This policy generally makes sense from an OSPM perspective but it leads to problems with wakeup from suspend on the TUXEDO Sirius 16 Gen 1 with a specific old BIOS. This manifests as a system hang. On the affected Device + BIOS combination, add a quirk for the root port of the problematic controller to ensure that these root ports are not put into D3hot at suspend. This patch is based on https://lore.kernel.org/linux-pci/20230708214457.1229-2-mario.limonciello@amd.com but with the added condition both in the documentation and in the code to apply only to the TUXEDO Sirius 16 Gen 1 with a specific old BIOS and only the affected root ports.Show less

In the Linux kernel, the following vulnerability has been resolved: landlock: Handle weird files A corrupted filesystem (e.g. bcachefs) might return weird files. Instead of throwing a warning and allowing access to such file, treat them as regular files.Show less

In the Linux kernel, the following vulnerability has been resolved: RDMA/rxe: Fix the warning "__rxe_cleanup+0x12c/0x170 [rdma_rxe]" The Call Trace is as below: " <TASK> ? show_regs.cold+0x1a/0x1f ? __rxe_cleanup+0x12c/0x170 [rdma_rxe] ? __warn+0x84/0xd0 ? __rxe_cleanup+0x12c/0x170 [rdma_rxe] ? report_bug+0x105/0x180 ? handle_bug+0x46/0x80 ? exc_invalid_op+0x19/0x70 ? asm_exc_invalid_op+0x1b/0x20 ? __rxe_cleanup+0x12c/0x170 [rdma_rxe] ? __rxe_cleanup+0x124/0x170 [rdma_rxe] rxe_destroy_qp.cold+0x24/0x29 [rdma_rxe] ib_destroy_qp_user+0x118/0x190 [ib_core] rdma_destroy_qp.cold+0x43/0x5e [rdma_cm] rtrs_cq_qp_destroy.cold+0x1d/0x2b [rtrs_core] rtrs_srv_close_work.cold+0x1b/0x31 [rtrs_server] process_one_work+0x21d/0x3f0 worker_thread+0x4a/0x3c0 ? process_one_work+0x3f0/0x3f0 kthread+0xf0/0x120 ? kthread_complete_and_exit+0x20/0x20 ret_from_fork+0x22/0x30 </TASK> " When too many rdma resources are allocated, rxe needs more time to handle these rdma resources. Sometimes with the current timeout, rxe can not release the rdma resources correctly. Compared with other rdma drivers, a bigger timeout is used.Show less

In the Linux kernel, the following vulnerability has been resolved: drm/v3d: Stop active perfmon if it is being destroyed If the active performance monitor (`v3d->active_perfmon`) is being destroyed, stop it first. Currently, the active perfmon is not stopped during destruction, leaving the `v3d->active_perfmon` pointer stale. This can lead to undefined behavior and instability. This patch ensures that the active perfmon is stopped before being destroyed, aligning with the behavior introduced in commit 7d1fd3638ee3 ("drm/v3d: Stop the active perfmon before being destroyed").Show less

In the Linux kernel, the following vulnerability has been resolved: tomoyo: don't emit warning in tomoyo_write_control() syzbot is reporting too large allocation warning at tomoyo_write_control(), for one can write a very very long line without new line character. To fix this warning, I use __GFP_NOWARN rather than checking for KMALLOC_MAX_SIZE, for practically a valid line should be always shorter than 32KB where the "too small to fail" memory-allocation rule applies. One might try to write a valid line that is longer than 32KB, but such request will likely fail with -ENOMEM. Therefore, I feel that separately returning -EINVAL when a line is longer than KMALLOC_MAX_SIZE is redundant. There is no need to distinguish over-32KB and over-KMALLOC_MAX_SIZE.Show less

In the Linux kernel, the following vulnerability has been resolved: firmware: qcom: scm: Fix missing read barrier in qcom_scm_get_tzmem_pool() Commit 2e4955167ec5 ("firmware: qcom: scm: Fix __scm and waitq completion variable initialization") introduced a write barrier in probe function to store global '__scm' variable. We all known barriers are paired (see memory-barriers.txt: "Note that write barriers should normally be paired with read or address-dependency barriers"), therefore accessing it from concurrent contexts requires read barrier. Previous commit added such barrier in qcom_scm_is_available(), so let's use that directly. Lack of this read barrier can result in fetching stale '__scm' variable value, NULL, and dereferencing it. Note that barrier in qcom_scm_is_available() satisfies here the control dependency.Show less

In the Linux kernel, the following vulnerability has been resolved: KVM: Explicitly verify target vCPU is online in kvm_get_vcpu() Explicitly verify the target vCPU is fully online _prior_ to clamping the index in kvm_get_vcpu(). If the index is "bad", the nospec clamping will generate '0', i.e. KVM will return vCPU0 instead of NULL. In practice, the bug is unlikely to cause problems, as it will only come into play if userspace or the guest is buggy or misbehaving, e.g. KVM may send interrupts to vCPU0 instead of dropping them on the floor. However, returning vCPU0 when it shouldn't exist per online_vcpus is problematic now that KVM uses an xarray for the vCPUs array, as KVM needs to insert into the xarray before publishing the vCPU to userspace (see commit c5b077549136 ("KVM: Convert the kvm->vcpus array to a xarray")), i.e. before vCPU creation is guaranteed to succeed. As a result, incorrectly providing access to vCPU0 will trigger a use-after-free if vCPU0 is dereferenced and kvm_vm_ioctl_create_vcpu() bails out of vCPU creation due to an error and frees vCPU0. Commit afb2acb2e3a3 ("KVM: Fix vcpu_array[0] races") papered over that issue, but in doing so introduced an unsolvable teardown conundrum. Preventing accesses to vCPU0 before it's fully online will allow reverting commit afb2acb2e3a3, without re-introducing the vcpu_array[0] UAF race.Show less