Linux

In the Linux kernel, the following vulnerability has been resolved: MIPS: DEC: Prevent initial console buffer from landing in XKPHYS In 64-bit configurations calling the initial console output handler from a kernel thread other than the initial one will result in a situation where the stack has been placed in the XKPHYS 64-bit memory segment and consequently so has been the buffer allocated there that is used as the argument corresponding to the `%s' output conversion specifier for the firmware's printf() entry point. This 64-bit address will then be truncated by 32-bit firmware, resulting in an attempt to access the wrong memory location, which in turn will cause all kinds of unpredictable behaviour, such as a kernel crash: Console: colour dummy device 160x64 Calibrating delay loop... 49.36 BogoMIPS (lpj=192512) pid_max: default: 32768 minimum: 301 CPU 0 Unable to handle kernel paging request at virtual address 000000000203bd00, epc == ffffffffbfc08364, ra == ffffffffbfc08800 Oops[#1]: CPU: 0 PID: 0 Comm: swapper Not tainted 5.18.0-rc2-00254-gfb649bda6f56-dirty #121 $ 0 : 0000000000000000 0000000000000001 0000000000000023 ffffffff80684ba0 $ 4 : 000000000203bd00 ffffffffbfc0f3b4 ffffffffffffffff 0000000000000073 $ 8 : 0a303d7469000000 0000000000000000 0000000000000073 ffffffffbfc0f473 $12 : 0000000000000002 0000000000000000 ffffffff80684c1c 0000000000000000 $16 : 0000000000000000 ffffffff80596dc9 0000000000000000 ffffffffbfc09240 $20 : ffffffff80684c40 ffffffffbfc0f400 000000000000002d 000000000000002b $24 : ffffffffffffffbf 000000000203bd00 $28 : ffffffff805f0000 ffffffff80684b58 0000000000000030 ffffffffbfc08800 Hi : 0000000000000000 Lo : 0000000000000aa8 epc : ffffffffbfc08364 0xffffffffbfc08364 ra : ffffffffbfc08800 0xffffffffbfc08800 Status: 140120e2 KX SX UX KERNEL EXL Cause : 00000008 (ExcCode 02) BadVA : 000000000203bd00 PrId : 00000430 (R4000SC) Modules linked in: Process swapper (pid: 0, threadinfo=(____ptrval____), task=(____ptrval____), tls=0000000000000000) Stack : 0000000000000000 0000000000000000 0000000000000000 0000004d0000004d 80684cc0806a2a40 80596dc80000004d 8061000000000000 bfc0850c80684c38 0000000000000000 000000000203bd00 0000000000000000 0000000000000000 0000000000000000 00000000bfc0f3b4 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000002500000000 0000000000000000 0000000000000000 802c1a7400000000 0203bd0080596dc8 0203bd4d69000000 6c61632000000018 5f746567646e6172 6c616320625f6d6f 5f736e5f6d6f7266 206361323778302b 303d74696e726320 806a0a38806b0000 806a0a38806b0000 00000000806b0000 80683c58806b0000 ... Call Trace: Code: a082ffff 03e00008 00601021 <80820000> 00001821 10400005 24840001 80820000 24630001 ---[ end trace 0000000000000000 ]--- Kernel panic - not syncing: Fatal exception in interrupt KN04 V2.1k (PC: 0xa0026768, SP: 0x806848e8) >> In this case the pointer in $4 was truncated from 0x980000000203bd00 to 0x000000000203bd00. This may happen when no final console driver has been enabled in the configuration and consequently the initial console continues being used late into bootstrap or with an upcoming change that will switch the zs driver to use a platform device, which in turn will make the console handover happen only after other kernel threads have already been started. Fix the issue by making the buffer static and initdata, and therefore placed in the CKSEG0 32-bit compatibility segment, observing that the console output handler is called with the console lock held, implying no need for this code to be reentrant. Add an assertion to verify the buffer actually has been placed in a compatibility segment.Show less

In the Linux kernel, the following vulnerability has been resolved: pwrseq: core: fix use-after-free in pwrseq_debugfs_seq_next() pwrseq_debugfs_seq_next() declares 'next' with __free(put_device), which causes put_device() to be called on the returned pointer when the variable goes out of scope. This results in a use-after-free since the seq_file framework receives a pointer whose reference has already been dropped. Simply removing __free(put_device) would fix the UAF but would leak the reference acquired by bus_find_next_device(), as stop() only calls up_read(&pwrseq_sem) and never releases the device reference. Fix this by making the reference counting consistent across all seq_file callbacks, matching the standard pattern used by PCI and SCSI: - start(): use get_device() so it returns a referenced pointer. - next(): explicitly put_device(curr) to release the previous device's reference (no NULL check needed - the seq_file framework only calls next() while the previous return was non-NULL). - stop(): put_device(data) to release the last iterated device's reference, with a NULL guard since stop() may be called with NULL when start() returned NULL or next() reached end-of-sequence.Show less

In the Linux kernel, the following vulnerability has been resolved: LoongArch: Report dying CPU to RCU in stop_this_cpu() This is a port of MIPS commit 9f3f3bdc6d9dac1 ("MIPS: smp: report dying CPU to RCU in stop_this_cpu()"). smp_send_stop() parks all secondary CPUs in stop_this_cpu(). And the function marks the CPU offline for the scheduler via set_cpu_online(false) but never informs RCU, so RCU keeps expecting a quiescent state from CPUs that are now spinning forever with interrupts disabled. As long as nothing waits for an RCU grace period after smp_send_stop() this is harmless, which is why it went unnoticed. However, since commit 91840be8f710370 ("irq_work: Fix use-after-free in irq_work_single() on PREEMPT_RT"), irq_work_sync() calls synchronize_rcu() on architectures without an irq_work self-IPI, i.e. where arch_irq_work_has_interrupt() returns false. Any irq_work_sync() issued in the reboot/shutdown/halt path after smp_send_stop() then blocks on a grace period that can never complete, hanging the reboot: WARNING: CPU: 0 PID: 15 at kernel/irq_work.c:144 irq_work_queue_on ... rcu: INFO: rcu_sched detected stalls on CPUs/tasks: rcu: Offline CPU 1 blocking current GP. rcu: Offline CPU 2 blocking current GP. rcu: Offline CPU 3 blocking current GP. This issue needs some hacks to reproduce, and it was not noticed on LoongArch because arch_irq_work_has_interrupt() usually returns true. Call rcutree_report_cpu_dead() once interrupts are disabled, mirroring the generic CPU-hotplug offline path, so RCU stops waiting on the parked CPUs and grace periods can still complete. LoongArch shuts down all CPUs here without going through the CPU-hotplug mechanism, so this report is not otherwise issued.Show less

In the Linux kernel, the following vulnerability has been resolved: fpga: region: fix use-after-free in child_regions_with_firmware() Move of_node_put(child_region) after the error print to avoid accessing freed memory when pr_err() references child_region. [ Yilun: Fix the Fixes tag ]Show less

In the Linux kernel, the following vulnerability has been resolved: MIPS: smp: report dying CPU to RCU in stop_this_cpu() smp_send_stop() parks all secondary CPUs in stop_this_cpu(). The function marks the CPU offline for the scheduler via set_cpu_online(false) but never informs RCU, so RCU keeps expecting a quiescent state from CPUs that are now spinning forever with interrupts disabled. As long as nothing waits for an RCU grace period after smp_send_stop() this is harmless, which is why it went unnoticed. Since commit 91840be8f710 ("irq_work: Fix use-after-free in irq_work_single() on PREEMPT_RT") however, irq_work_sync() calls synchronize_rcu() on architectures without an irq_work self-IPI, i.e. where arch_irq_work_has_interrupt() returns false. That is the asm-generic default used by MIPS. Any irq_work_sync() issued in the reboot/shutdown path after smp_send_stop() then blocks on a grace period that can never complete, hanging the reboot: WARNING: CPU: 0 PID: 15 at kernel/irq_work.c:144 irq_work_queue_on ... rcu: INFO: rcu_sched detected stalls on CPUs/tasks: rcu: Offline CPU 1 blocking current GP. rcu: Offline CPU 2 blocking current GP. rcu: Offline CPU 3 blocking current GP. This issue was noticed on several Realtek MIPS switch SoCs (MIPS interAptiv) and came up during kernel bump downstream in OpenWrt from 6.18.33 to 6.18.34, after the backport of the patch to the 6.18 stable branch. The patch also has been backported all the way back to 6.1. Call rcutree_report_cpu_dead() once interrupts are disabled, mirroring the generic CPU-hotplug offline path, so RCU stops waiting on the parked CPUs and grace periods can still complete. MIPS shuts down all CPUs here without going through the CPU-hotplug mechanism, so this report is not otherwise issued. Reporting a dying CPU to RCU outside the regular hotplug offline path is not unprecedented: arm64 does the same in cpu_die_early(). There it is an exception for a CPU that was coming online and is aborting bringup, rather than the default shutdown action as on MIPS.Show less

In the Linux kernel, the following vulnerability has been resolved: KVM: x86: hyper-v: Bound the bank index when querying sparse banks When checking if a VP ID is included in a sparse bank set, explicitly check that the ID can actually be contained in a sparse bank (the TLFS allows for a maximum of 64 banks of 64 vCPUs each). When handling a paravirtual TLB flush for L2, the VP ID is copied verbatim from the enlightened VMCS, without any bounds check, i.e. isn't guaranteed to be under the limit of 4096. Failure to check the bounds of the VP ID leads to an out-of-bounds read when testing the sparse bank, and super strictly speaking could lead to KVM performing an unnecessary TLB flush for an L2 vCPU. ================================================================== BUG: KASAN: use-after-free in hv_is_vp_in_sparse_set+0x85/0x100 [kvm] Read of size 8 at addr ffff88811ba5f598 by task hyperv_evmcs/2802 CPU: 12 UID: 1000 PID: 2802 Comm: hyperv_evmcs Not tainted 7.1.0-rc2 #7 PREEMPT Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 Call Trace: <TASK> dump_stack_lvl+0x51/0x60 print_report+0xcb/0x5d0 kasan_report+0xb4/0xe0 kasan_check_range+0x35/0x1b0 hv_is_vp_in_sparse_set+0x85/0x100 [kvm] kvm_hv_flush_tlb+0xe9e/0x16c0 [kvm] kvm_hv_hypercall+0xe6b/0x1e60 [kvm] vmx_handle_exit+0x485/0x1b60 [kvm_intel] kvm_arch_vcpu_ioctl_run+0x22e3/0x5070 [kvm] kvm_vcpu_ioctl+0x5d0/0x10c0 [kvm] __x64_sys_ioctl+0x129/0x1a0 do_syscall_64+0xb9/0xcf0 entry_SYSCALL_64_after_hwframe+0x4b/0x53 RIP: 0033:0x7f0e62d1a9bf </TASK> The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffffffffffffffff pfn:0x11ba5f flags: 0x4000000000000000(zone=1) raw: 4000000000000000 0000000000000000 00000000ffffffff 0000000000000000 raw: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88811ba5f480: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff88811ba5f500: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff >ffff88811ba5f580: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ^ ffff88811ba5f600: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff88811ba5f680: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ================================================================== Disabling lock debugging due to kernel taint Opportunistically add a compile time assertion to ensure the maximum number of sparse banks exactly matches the number of possible bits in the passed in mask. [sean: add KASAN splat, drop comment, add assert, massage changelog]Show less

In the Linux kernel, the following vulnerability has been resolved: power: reset: linkstation-poweroff: fix use-after-free in the linkstation_poweroff_init() Move of_node_put(dn) after the of_match_node() call, which still needs the node pointer. The node reference is correctly released after use.Show less

In the Linux kernel, the following vulnerability has been resolved: fbdev: modedb: fix a possible UAF in fb_find_mode() If mode_option is NULL, it is assigned from mode_option_buf: if (!mode_option) { fb_get_options(NULL, &mode_option_buf); mode_option = mode_option_buf; } Later, name is assigned from mode_option: const char *name = mode_option; However, mode_option_buf is freed before name is no longer used: kfree(mode_option_buf); while name is still accessed by: if ((name_matches(db[i], name, namelen) || Since name aliases mode_option_buf, this may result in a use-after-free. Fix this by extending the lifetime of mode_option_buf until the end of the function by using scope-based resource management for cleanup.Show less

In the Linux kernel, the following vulnerability has been resolved: drivers/base/memory: set mem->altmap after successful device registration If __add_memory_block() fails at xa_store() (under memory pressure for example), device_unregister() is called, which eventually triggers memory_block_release() with mem->altmap still set, causing a WARN_ON(mem->altmap). This was triggered by modifying virtio-mem driver. Fix this by delaying the assignment of mem->altmap until after __add_memory_block() has succeeded.Show less

In the Linux kernel, the following vulnerability has been resolved: ASoC: codecs: simple-mux: Fix enum control bounds check simple_mux_control_put() rejects values greater than e->items, but enum control values are zero based. For the two-entry mux used by this driver, valid values are 0 and 1, so value 2 must be rejected as well. Accepting e->items can store an invalid mux state, pass it to the GPIO setter, and pass it on to the DAPM mux update path where it is used as an index into the enum text array. Use the same >= e->items check used by the ASoC enum helpers.Show less

In the Linux kernel, the following vulnerability has been resolved: usb: gadget: net2280: Fix double free in probe error path usb_initialize_gadget() installs gadget_release() as the release callback for the embedded gadget device. The struct net2280 instance is therefore released through gadget_release() when the gadget device's last reference is dropped. The probe error path calls net2280_remove(), which tears down the partially initialized device and drops the gadget reference with usb_put_gadget(). Calling kfree(dev) afterwards can free the same object again. Drop the explicit kfree() and let the gadget device release callback handle the final free. This issue was found by a static analysis tool I am developing.Show less

In the Linux kernel, the following vulnerability has been resolved: gpio: rockchip: teardown bugs and resource leaks Address several teardown issues and resource leaks in the driver's remove path and error handling: 1. Debounce clock reference leak: The debounce clock (bank->db_clk) is obtained using of_clk_get() which increments the clock's reference count, but clk_put() is never called. Register a devm action to cleanly release it on unbind. Note that of_clk_get(..., 1) remains necessary over devm_clk_get() because the DT binding does not define clock-names, precluding name-based lookup. 2. Unregistered chained IRQ handler: The chained IRQ handler is not disconnected in remove(). If a stray interrupt fires after the driver is removed, the kernel attempts to execute a stale handler, leading to a panic. Fix this by clearing the handler in remove(). 3. IRQ domain leak: The linear IRQ domain and its generic chips are allocated manually during probe but never removed. Remove the IRQ domain during driver teardown to free the associated generic chips and mappings. [Bartosz: don't emit an error message on devres allocation failure]Show less

In the Linux kernel, the following vulnerability has been resolved: media: rc: igorplugusb: fix control request setup packet Commit eac69475b01f ("media: rc: igorplugusb: heed coherency rules") changed the control request storage from an embedded struct to an allocated pointer so it can obey DMA coherency rules. However, the driver still passes &ir->request to usb_fill_control_urb(). That points the URB setup packet at the pointer field itself rather than at the allocated struct usb_ctrlrequest. USB core then interprets pointer bytes as the setup packet. This can produce an invalid bRequestType and trigger the control direction warning reported by syzbot: usb 2-1: BOGUS control dir, pipe 80003580 doesn't match bRequestType 0 Pass ir->request itself as the setup packet.Show less

In the Linux kernel, the following vulnerability has been resolved: mm/damon/sysfs-schemes: delete tried region in regions_rmdirs() DAMON sysfs maintains the DAMOS tried region directory objects via a linked list. When the user requests refresh of the directories, DAMON sysfs removes all the region directories first, and then generate updated regions directory on the empty space. The removal function (damon_sysfs_scheme_regions_rm_dirs()) only puts the kobj objects. Deletion of the container region object from the linked list is done inside the kobj release callback function. If somehow the callback invocation is delayed, the list will contain regions list that gonna be freed. If the updated region directories creation is started in this situation, the list can be corrupted and use-after-free can happen. Because the kobj objects are managed by only DAMON sysfs, the issue cannot happen in normal situation. But, such delays can be made on kernels that built with CONFIG_DEBUG_KOBJECT_RELEASE. On the kernel, the issue can indeed be reproduced like below. # damo start --damos_action stat # cd /sys/kernel/mm/damon/admin/kdamonds/0/ # for i in {1..10}; do echo update_schemes_tried_regions > state; done # dmesg | grep underflow [ 89.296152] refcount_t: underflow; use-after-free. Fix the issue by removing the region object from the list when decrementing the reference count. Also update damos_sysfs_populate_region_dir() to add the region object to the list only after the kobject_init_and_add() is success, so that fail of kobject_init_and_add() is not leaving the deallocated object on the list. The issue was discovered [1] by Sashiko.Show less

In the Linux kernel, the following vulnerability has been resolved: gpio: shared: fix deadlock on shared proxy's parent removal Commit 710abda58055 ("gpio: shared: call gpio_chip::of_xlate() if set") used the mutex embedded in struct gpio_shared_entry to protect the offset field which now can be modified after assignment. The critical section however is too wide and introduced a potential deadlock on the removal of the shared GPIO proxy's parent. Make the critical section shorter - only protect the offset when it's being read. While at it: mention the fact that the entry lock is now also used to protect against concurrent access to the offset field in the structure's documentation.Show less

In the Linux kernel, the following vulnerability has been resolved: Input: elan_i2c - validate firmware size before use Ensure that the firmware file is large enough to contain the expected number of pages and the signature (which resides at the end of the firmware blob) before accessing them to prevent potential out-of-bounds reads.Show less

In the Linux kernel, the following vulnerability has been resolved: i2c: davinci: fix division by zero on missing clock-frequency When the 'clock-frequency' property is missing from the device tree, the driver falls back to DAVINCI_I2C_DEFAULT_BUS_FREQ. However, this macro was defined in kHz (100), whereas the device tree property is expected in Hz. The probe function divided the fallback value by 1000, causing integer truncation that resulted in dev->bus_freq = 0. This triggered a deterministic division-by-zero kernel panic when calculating clock dividers later in the probe sequence. Fix this by redefining DAVINCI_I2C_DEFAULT_BUS_FREQ in Hz (100000) to match the expected device tree property unit, allowing the existing division logic to work correctly for both cases.Show less

In the Linux kernel, the following vulnerability has been resolved: x86/ftrace: Relocate %rip-relative percpu refs in dynamic trampolines With CONFIG_CALL_DEPTH_TRACKING enabled on an x86 retbleed-affected platform (eg: Skylake), with retbleed=stuff, registering a dynamic ftrace trampoline crashes on the first call into the traced function: BUG: unable to handle page fault for address: ffff88817ae18880 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page PGD 4b53067 P4D 4b53067 PUD 0 Oops: Oops: 0002 [#1] SMP PTI CPU: 3 UID: 0 PID: 187 Comm: usleep Not tainted 7.0.10 #243 PREEMPT(full) Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.17.0-2-2 04/01/2014 Code: 24 78 00 00 00 00 48 89 ea 48 89 54 24 20 48 8b b4 24 b8 00 00 00 48 8b bc 24 b0 00 00 00 48 89 bc 24 80 00 00 00 48 83 ef 05 <65> 48 c1 3d 1f a8 b6 02 05 48 8b 15 f6 00 00 00 4c 89 3c 24 4c 89 Call Trace: <TASK> ? find_held_lock ? exc_page_fault ? lock_release ? __x64_sys_clock_nanosleep ? lockdep_hardirqs_on_prepare ? trace_hardirqs_on __x64_sys_clock_nanosleep do_syscall_64 ? exc_page_fault ? call_depth_return_thunk entry_SYSCALL_64_after_hwframe ... Kernel panic - not syncing: Fatal exception This small reproducer allows to easily trigger the crash: # echo 'p __x64_sys_clock_nanosleep' > /sys/kernel/tracing/kprobe_events # echo 1 > /sys/kernel/tracing/events/kprobes/p___x64_sys_clock_nanosleep_0/enable # usleep 1 Monitoring the crash under GDB points to the exact instruction in charge of incrementing the call depth: sarq $5, %gs:__x86_call_depth(%rip) This instruction matches the one inserted by the ftrace_regs_caller from ftrace_64.S. This emitted code was likely working fine until the introduction of 59bec00ace28 ("x86/percpu: Introduce %rip-relative addressing to PER_CPU_VAR()"): it has made the call depth accounting addressing relative to $rip, instead of being based on an absolute address. As this code exact location depends on where the trampoline lives in memory, the corresponding displacement needs to be adjusted at runtime to actually correctly find the per-cpu __x86_call_depth value, otherwise the targeted address is wrong, leading to the page fault seen above. Fix the %rip-relative displacement of the copied CALL_DEPTH_ACCOUNT instruction (from ftrace_regs_caller) by calling text_poke_apply_relocation(), as it is done for example by the x86 BPF JIT compiler through x86_call_depth_emit_accounting(). This corrects both CALL_DEPTH_ACCOUNT slots, in ftrace_caller and ftrace_regs_caller. [ bp: Massage. ]Show less

In the Linux kernel, the following vulnerability has been resolved: tty: serial: pch_uart: add check for dma_alloc_coherent() Add a check for dma_alloc_coherent() failure to prevent a potential NULL pointer dereference in dma_handle_rx(). Properly release DMA channels and the PCI device reference using a goto ladder if the allocation fails.Show less

In the Linux kernel, the following vulnerability has been resolved: usb: gadget: uvc: hold opts->lock across XU walks in uvc_function_bind uvc_function_bind() walks &opts->extension_units twice without holding opts->lock: - directly, for the iExtension string-descriptor fixup loop; - indirectly, four times via uvc_copy_descriptors() (once per speed), where the helper iterates uvc->desc.extension_units (which aliases &opts->extension_units) to size and emit XU descriptors. The configfs side (uvcg_extension_make / uvcg_extension_drop, in drivers/usb/gadget/function/uvc_configfs.c) takes opts->lock around its list_add_tail / list_del operations. A privileged userspace process that holds the configfs subtree open and writes the gadget UDC name to bind the function while concurrently rmdir()'ing an extensions subdir can race uvcg_extension_drop() against the bind-time list walks and dereference a freed struct uvcg_extension. Hold opts->lock from the start of the XU string-descriptor fixup through the last uvc_copy_descriptors() call, releasing on the descriptor-error path via a new error_unlock label that drops the lock before falling through to the existing error label. This matches the locking discipline of the configfs callbacks and removes the only remaining unsynchronised reader of the XU list during bind. Reachability: only privileged processes that can mount configfs and write to gadget UDC files can trigger the race, so this is a correctness fix rather than a security boundary.Show less