In the Linux kernel, the following vulnerability has been resolved: PCI: s390: Fix use-after-free of PCI resources with per-function hotplug On s390 PCI functions may be hotplugged individually even when they belong to a multi-function device. In particular on an SR-IOV device VFs may be removed and later re-added. In commit a50297cf8235 ("s390/pci: separate zbus creation from scanning") it was missed however that struct pci_bus and struct zpci_bus's resource list retained a reference to the PCI functions MMIO resources even though those resources are released and freed on hot-unplug. These stale resources may subsequently be claimed when the PCI function re-appears resulting in use-after-free. One idea of fixing this use-after-free in s390 specific code that was investigated was to simply keep resources around from the moment a PCI function first appeared until the whole virtual PCI bus created for a multi-function device disappears. The problem with this however is that due to the requirement of artificial MMIO addreesses (address cookies) extra logic is then needed to keep the address cookies compatible on re-plug. At the same time the MMIO resources semantically belong to the PCI function so tying their lifecycle to the function seems more logical. Instead a simpler approach is to remove the resources of an individually hot-unplugged PCI function from the PCI bus's resource list while keeping the resources of other PCI functions on the PCI bus untouched. This is done by introducing pci_bus_remove_resource() to remove an individual resource. Similarly the resource also needs to be removed from the struct zpci_bus's resource list. It turns out however, that there is really no need to add the MMIO resources to the struct zpci_bus's resource list at all and instead we can simply use the zpci_bar_struct's resource pointer directly.

In the Linux kernel, the following vulnerability has been resolved: io-wq: check that the predecessor is hashed in io_wq_remove_pending() io_wq_remove_pending() needs to fix up wq->hash_tail[] if the cancelled work was the tail of its hash bucket. When doing this, it checks whether the preceding entry in acct->work_list has the same hash value, but never checks that the predecessor is hashed at all. io_get_work_hash() is simply atomic_read(&work->flags) >> IO_WQ_HASH_SHIFT, and the hash bits are never set for non-hashed work, so it returns 0. Thus, when a hashed bucket-0 work is cancelled while a non-hashed work is its list predecessor, the check spuriously passes and a pointer to the non-hashed io_kiocb is stored in wq->hash_tail[0]. Because non-hashed work is dequeued via the fast path in io_get_next_work(), which never touches hash_tail[], the stale pointer is never cleared. Therefore, after the non-hashed io_kiocb completes and is freed back to req_cachep, wq->hash_tail[0] is a dangling pointer. The io_wq is per-task (tctx->io_wq) and survives ring open/close, so the dangling pointer persists for the lifetime of the task; the next hashed bucket-0 enqueue dereferences it in io_wq_insert_work() and wq_list_add_after() writes through freed memory. Add the missing io_wq_is_hashed() check so a non-hashed predecessor never inherits a hash_tail[] slot.

Use After Free vulnerability in nfc sockets in the Linux Kernel before 5.12.4 allows local attackers to elevate their privileges. In typical configurations, the issue can only be triggered by a privileged local user with the CAP_NET_RAW capability.

In the Linux kernel, the following vulnerability has been resolved: lib: test_hmm: evict device pages on file close to avoid use-after-free Patch series "Minor hmm_test fixes and cleanups". Two bugfixes a cleanup for the HMM kernel selftests. These were mostly reported by Zenghui Yu with special thanks to Lorenzo for analysing and pointing out the problems. This patch (of 3): When dmirror_fops_release() is called it frees the dmirror struct but doesn't migrate device private pages back to system memory first. This leaves those pages with a dangling zone_device_data pointer to the freed dmirror. If a subsequent fault occurs on those pages (eg. during coredump) the dmirror_devmem_fault() callback dereferences the stale pointer causing a kernel panic. This was reported [1] when running mm/ksft_hmm.sh on arm64, where a test failure triggered SIGABRT and the resulting coredump walked the VMAs faulting in the stale device private pages. Fix this by calling dmirror_device_evict_chunk() for each devmem chunk in dmirror_fops_release() to migrate all device private pages back to system memory before freeing the dmirror struct. The function is moved earlier in the file to avoid a forward declaration.

In the Linux kernel, the following vulnerability has been resolved: mtd: docg3: fix use-after-free in docg3_release() In docg3_release(), the docg3 pointer is obtained from cascade->floors[0]->priv before the loop that calls doc_release_device() on each floor. doc_release_device() frees the docg3 struct via kfree(docg3) at line 1881. After the loop, docg3->cascade->bch dereferences the already-freed pointer. Fix this by accessing cascade->bch directly, which is equivalent since docg3->cascade points back to the same cascade struct, and is already available as a local variable. This also removes the now-unused docg3 local variable.

In the Linux kernel, the following vulnerability has been resolved: spi: topcliff-pch: fix use-after-free on unbind Give the driver a chance to flush its queue before releasing the DMA buffers on driver unbind

In the Linux kernel, the following vulnerability has been resolved: pmdomain: mediatek: fix use-after-free in scpsys_get_bus_protection_legacy() In scpsys_get_bus_protection_legacy(), of_find_node_with_property() returns a device node with its reference count incremented. The function then calls of_node_put(node) before checking whether syscon_regmap_lookup_by_phandle() returns an error. If an error occurs, dev_err_probe() dereferences the node pointer to print diagnostic information, but the node memory may have already been freed due to the earlier of_node_put(), leading to a use-after-free vulnerability. Fix this by moving the of_node_put() call after the error check, ensuring the node is still valid when accessed in the error path.

A use-after-free flaw was found in the io_uring in Linux kernel, where a local attacker with a user privilege could cause a denial of service problem on the system The issue results from the lack of validating the existence of an object prior to performing operations on the object by not incrementing the file reference counter while in use. The highest threat from this vulnerability is to data integrity, confidentiality and system availability.

In the Linux kernel, the following vulnerability has been resolved: tee: optee: prevent use-after-free when the client exits before the supplicant Commit 70b0d6b0a199 ("tee: optee: Fix supplicant wait loop") made the client wait as killable so it can be interrupted during shutdown or after a supplicant crash. This changes the original lifetime expectations: the client task can now terminate while the supplicant is still processing its request. If the client exits first it removes the request from its queue and kfree()s it, while the request ID remains in supp->idr. A subsequent lookup on the supplicant path then dereferences freed memory, leading to a use-after-free. Serialise access to the request with supp->mutex: * Hold supp->mutex in optee_supp_recv() and optee_supp_send() while looking up and touching the request. * Let optee_supp_thrd_req() notice that the client has terminated and signal optee_supp_send() accordingly. With these changes the request cannot be freed while the supplicant still has a reference, eliminating the race.

In the Linux kernel, the following vulnerability has been resolved: drm/xe/eustall: Fix drm_dev_put called before stream disable in close In xe_eu_stall_stream_close(), drm_dev_put() is called before the stream is disabled and its resources are freed. If this drops the last reference, the device structures could be freed while the subsequent cleanup code still accesses them, leading to a use-after-free. Fix this by moving drm_dev_put() after all device accesses are complete. This matches the ordering in xe_oa_release(). (cherry picked from commit 35aff528f7297e949e5e19c9cd7fd748cf1cf21c)

In the Linux kernel, the following vulnerability has been resolved: drm/nouveau: avoid a use-after-free when BO init fails nouveau_bo_init() is backed by ttm_bo_init() and ferries its return code back to the caller. On failures, ttm_bo_init() invokes the provided destructor which should de-initialize and free the memory. Thus, when nouveau_bo_init() returns an error the gem object has already been released and the memory freed by nouveau_bo_del_ttm().

An issue was discovered in the Linux kernel before 5.7. The KVM subsystem allows out-of-range access to memslots after a deletion, aka CID-0774a964ef56. This affects arch/s390/kvm/kvm-s390.c, include/linux/kvm_host.h, and virt/kvm/kvm_main.c.

In the Linux kernel, the following vulnerability has been resolved: futex: Drop CLONE_THREAD requirement for private default hash alloc Currently need_futex_hash_allocate_default() depends on strict pthread semantics, abusing CLONE_THREAD. This breaks the non-concurrency assumptions when doing the mm->futex_ref pcpu allocations, leading to bugs[0] when sharing the mm in other ways; ie: BUG: KASAN: slab-use-after-free in futex_hash_put ... where the +1 bias can end up on a percpu counter that mm->futex_ref no longer points at. Loosen the check to cover any CLONE_VM clone, except vfork(). Excluding vfork keeps the existing paths untouched (no overhead), and we can't race in the first place: either the parent is suspended and the child runs alone, or mm->futex_ref is already allocated from an earlier CLONE_VM.

In the Linux kernel, the following vulnerability has been resolved: greybus: raw: fix use-after-free if write is called after disconnect If a user writes to the chardev after disconnect has been called, the kernel panics with the following trace (with CONFIG_INIT_ON_FREE_DEFAULT_ON=y): BUG: kernel NULL pointer dereference, address: 0000000000000218 ... Call Trace: <TASK> gb_operation_create_common+0x61/0x180 gb_operation_create_flags+0x28/0xa0 gb_operation_sync_timeout+0x6f/0x100 raw_write+0x7b/0xc7 [gb_raw] vfs_write+0xcf/0x420 ? task_mm_cid_work+0x136/0x220 ksys_write+0x63/0xe0 do_syscall_64+0xa4/0x290 entry_SYSCALL_64_after_hwframe+0x77/0x7f Disconnect calls gb_connection_destroy, which ends up freeing the connection object. When gb_operation_sync is called in the write file operations, its gets a freed connection as parameter and the kernel panics. The gb_connection_destroy cannot be moved out of the disconnect function, as the Greybus subsystem expect all connections belonging to a bundle to be destroyed when disconnect returns. To prevent this bug, use a rw lock to synchronize access between write and disconnect. This guarantees that the write function doesn't try to use a disconnected connection.

In the Linux kernel, the following vulnerability has been resolved: media: atomisp: Fix use after free in atomisp_alloc_css_stat_bufs() The "s3a_buf" is freed along with all the other items on the "asd->s3a_stats" list. It leads to a double free and a use after free.

In the Linux kernel, the following vulnerability has been resolved: net/sched: taprio: fix use-after-free in advance_sched() on schedule switch In advance_sched(), when should_change_schedules() returns true, switch_schedules() is called to promote the admin schedule to oper. switch_schedules() queues the old oper schedule for RCU freeing via call_rcu(), but 'next' still points into an entry of the old oper schedule. The subsequent 'next->end_time = end_time' and rcu_assign_pointer(q->current_entry, next) are use-after-free. Fix this by selecting 'next' from the new oper schedule immediately after switch_schedules(), and using its pre-calculated end_time. setup_first_end_time() sets the first entry's end_time to base_time + interval when the schedule is installed, so the value is already correct. The deleted 'end_time = sched_base_time(admin)' assignment was also harmful independently: it would overwrite the new first entry's pre-calculated end_time with just base_time.

A use-after-free flaw was found in D-Bus Development branch <= 1.13.16, dbus-1.12.x stable branch <= 1.12.18, and dbus-1.10.x and older branches <= 1.10.30 when a system has multiple usernames sharing the same UID. When a set of policy rules references these usernames, D-Bus may free some memory in the heap, which is still used by data structures necessary for the other usernames sharing the UID, possibly leading to a crash or other undefined behaviors

In the Linux kernel, the following vulnerability has been resolved: ip6mr: fix UAF issue in ip6mr_sk_done() when addrconf_init_net() failed If the initialization fails in calling addrconf_init_net(), devconf_all is the pointer that has been released. Then ip6mr_sk_done() is called to release the net, accessing devconf->mc_forwarding directly causes invalid pointer access. The process is as follows: setup_net() ops_init() addrconf_init_net() all = kmemdup(...) ---> alloc "all" ... net->ipv6.devconf_all = all; __addrconf_sysctl_register() ---> failed ... kfree(all); ---> ipv6.devconf_all invalid ... ops_exit_list() ... ip6mr_sk_done() devconf = net->ipv6.devconf_all; //devconf is invalid pointer if (!devconf || !atomic_read(&devconf->mc_forwarding)) The following is the Call Trace information: BUG: KASAN: use-after-free in ip6mr_sk_done+0x112/0x3a0 Read of size 4 at addr ffff888075508e88 by task ip/14554 Call Trace: <TASK> dump_stack_lvl+0x8e/0xd1 print_report+0x155/0x454 kasan_report+0xba/0x1f0 kasan_check_range+0x35/0x1b0 ip6mr_sk_done+0x112/0x3a0 rawv6_close+0x48/0x70 inet_release+0x109/0x230 inet6_release+0x4c/0x70 sock_release+0x87/0x1b0 igmp6_net_exit+0x6b/0x170 ops_exit_list+0xb0/0x170 setup_net+0x7ac/0xbd0 copy_net_ns+0x2e6/0x6b0 create_new_namespaces+0x382/0xa50 unshare_nsproxy_namespaces+0xa6/0x1c0 ksys_unshare+0x3a4/0x7e0 __x64_sys_unshare+0x2d/0x40 do_syscall_64+0x35/0x80 entry_SYSCALL_64_after_hwframe+0x46/0xb0 RIP: 0033:0x7f7963322547 </TASK> Allocated by task 14554: kasan_save_stack+0x1e/0x40 kasan_set_track+0x21/0x30 __kasan_kmalloc+0xa1/0xb0 __kmalloc_node_track_caller+0x4a/0xb0 kmemdup+0x28/0x60 addrconf_init_net+0x1be/0x840 ops_init+0xa5/0x410 setup_net+0x5aa/0xbd0 copy_net_ns+0x2e6/0x6b0 create_new_namespaces+0x382/0xa50 unshare_nsproxy_namespaces+0xa6/0x1c0 ksys_unshare+0x3a4/0x7e0 __x64_sys_unshare+0x2d/0x40 do_syscall_64+0x35/0x80 entry_SYSCALL_64_after_hwframe+0x46/0xb0 Freed by task 14554: kasan_save_stack+0x1e/0x40 kasan_set_track+0x21/0x30 kasan_save_free_info+0x2a/0x40 ____kasan_slab_free+0x155/0x1b0 slab_free_freelist_hook+0x11b/0x220 __kmem_cache_free+0xa4/0x360 addrconf_init_net+0x623/0x840 ops_init+0xa5/0x410 setup_net+0x5aa/0xbd0 copy_net_ns+0x2e6/0x6b0 create_new_namespaces+0x382/0xa50 unshare_nsproxy_namespaces+0xa6/0x1c0 ksys_unshare+0x3a4/0x7e0 __x64_sys_unshare+0x2d/0x40 do_syscall_64+0x35/0x80 entry_SYSCALL_64_after_hwframe+0x46/0xb0

A locking issue was discovered in the tty subsystem of the Linux kernel through 5.9.13. drivers/tty/tty_jobctrl.c allows a use-after-free attack against TIOCSPGRP, aka CID-54ffccbf053b.

A flaw was found in the Linux kernel’s implementation of MIDI, where an attacker with a local account and the permissions to issue ioctl commands to midi devices could trigger a use-after-free issue. A write to this specific memory while freed and before use causes the flow of execution to change and possibly allow for memory corruption or privilege escalation. The highest threat from this vulnerability is to confidentiality, integrity, as well as system availability.

The Linux kernel 4.9.x before 4.9.233, 4.14.x before 4.14.194, and 4.19.x before 4.19.140 has a use-after-free because skcd->no_refcnt was not considered during a backport of a CVE-2020-14356 patch. This is related to the cgroups feature.

A vulnerability was found in the Linux Kernel where the function sunkbd_reinit having been scheduled by sunkbd_interrupt before sunkbd being freed. Though the dangling pointer is set to NULL in sunkbd_disconnect, there is still an alias in sunkbd_reinit causing Use After Free.

A vulnerability was found in Linux Kernel, where a refcount leak in llcp_sock_connect() causing use-after-free which might lead to privilege escalations.

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: btmtk: avoid UAF in btmtk_process_coredump hci_devcd_append may lead to the release of the skb, so it cannot be accessed once it is called. ================================================================== BUG: KASAN: slab-use-after-free in btmtk_process_coredump+0x2a7/0x2d0 [btmtk] Read of size 4 at addr ffff888033cfabb0 by task kworker/0:3/82 CPU: 0 PID: 82 Comm: kworker/0:3 Tainted: G U 6.6.40-lockdep-03464-g1d8b4eb3060e #1 b0b3c1cc0c842735643fb411799d97921d1f688c Hardware name: Google Yaviks_Ufs/Yaviks_Ufs, BIOS Google_Yaviks_Ufs.15217.552.0 05/07/2024 Workqueue: events btusb_rx_work [btusb] Call Trace: <TASK> dump_stack_lvl+0xfd/0x150 print_report+0x131/0x780 kasan_report+0x177/0x1c0 btmtk_process_coredump+0x2a7/0x2d0 [btmtk 03edd567dd71a65958807c95a65db31d433e1d01] btusb_recv_acl_mtk+0x11c/0x1a0 [btusb 675430d1e87c4f24d0c1f80efe600757a0f32bec] btusb_rx_work+0x9e/0xe0 [btusb 675430d1e87c4f24d0c1f80efe600757a0f32bec] worker_thread+0xe44/0x2cc0 kthread+0x2ff/0x3a0 ret_from_fork+0x51/0x80 ret_from_fork_asm+0x1b/0x30 </TASK> Allocated by task 82: stack_trace_save+0xdc/0x190 kasan_set_track+0x4e/0x80 __kasan_slab_alloc+0x4e/0x60 kmem_cache_alloc+0x19f/0x360 skb_clone+0x132/0xf70 btusb_recv_acl_mtk+0x104/0x1a0 [btusb] btusb_rx_work+0x9e/0xe0 [btusb] worker_thread+0xe44/0x2cc0 kthread+0x2ff/0x3a0 ret_from_fork+0x51/0x80 ret_from_fork_asm+0x1b/0x30 Freed by task 1733: stack_trace_save+0xdc/0x190 kasan_set_track+0x4e/0x80 kasan_save_free_info+0x28/0xb0 ____kasan_slab_free+0xfd/0x170 kmem_cache_free+0x183/0x3f0 hci_devcd_rx+0x91a/0x2060 [bluetooth] worker_thread+0xe44/0x2cc0 kthread+0x2ff/0x3a0 ret_from_fork+0x51/0x80 ret_from_fork_asm+0x1b/0x30 The buggy address belongs to the object at ffff888033cfab40 which belongs to the cache skbuff_head_cache of size 232 The buggy address is located 112 bytes inside of freed 232-byte region [ffff888033cfab40, ffff888033cfac28) The buggy address belongs to the physical page: page:00000000a174ba93 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x33cfa head:00000000a174ba93 order:1 entire_mapcount:0 nr_pages_mapped:0 pincount:0 anon flags: 0x4000000000000840(slab|head|zone=1) page_type: 0xffffffff() raw: 4000000000000840 ffff888100848a00 0000000000000000 0000000000000001 raw: 0000000000000000 0000000080190019 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888033cfaa80: fb fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc ffff888033cfab00: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb >ffff888033cfab80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888033cfac00: fb fb fb fb fb fc fc fc fc fc fc fc fc fc fc fc ffff888033cfac80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== Check if we need to call hci_devcd_complete before calling hci_devcd_append. That requires that we check data->cd_info.cnt >= MTK_COREDUMP_NUM instead of data->cd_info.cnt > MTK_COREDUMP_NUM, as we increment data->cd_info.cnt only once the call to hci_devcd_append succeeds.

In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_queue: hold bridge skb->dev while queued br_pass_frame_up() rewrites skb->dev from the ingress port to the bridge master before queueing bridge LOCAL_IN packets. NFQUEUE only holds references on state.in/out and bridge physdevs, so a queued bridge packet can retain a freed bridge master in skb->dev until reinjection. When the verdict is reinjected later, br_netif_receive_skb() re-enters the receive path with skb->dev still pointing at the freed bridge master, triggering a use-after-free. Store skb->dev in the queue entry, hold a reference on it for the queue lifetime, and use the saved device when dropping queued packets during NETDEV_DOWN handling.

In the Linux kernel, the following vulnerability has been resolved: drm/xe/dma-buf: handle empty bo and UAF races There look to be some nasty races here when triggering the invalidate_mappings hook: 1) We do xe_bo_alloc() followed by the attach, before the actual full bo init step in xe_dma_buf_init_obj(). However the bo is visible on the attachments list after the attach. This is bad since exporter driver, say amdgpu, can at any time call back into our invalidate_mappings hook, with an empty/bogus bo, leading to potential bugs/crashes. 2) Similar to 1) but here we get a UAF, when the invalidate_mappings hook is triggered. For example, we get as far as xe_bo_init_locked() but this fails in some way. But here the bo will be freed on error, but we still have it attached from dma-buf pov, so if the invalidate_mappings is now triggered then the bo we access is gone and we trigger UAF and more bugs/crashes. To fix this, move the attach step until after we actually have a fully set up buffer object. Note that the bo is not published to userspace until later, so not sure what the comment "Don't publish the bo until we have a valid attachment", is referring to. We have at least two different customers reporting hitting a NULL ptr deref in evict_flags when importing something from amdgpu, followed by triggering the evict flow. Hit rate is also pretty low, which would hint at some kind of race, so something like 1) or 2) might explain this. v2: - Shuffle the order of the ops slightly (no functional change) - Improve the comment to better explain the ordering (Matt B) (cherry picked from commit af1f2ad0c59fe4e2f924c526f66e968289d77971)

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: ISO: Fix a use-after-free of the hci_conn pointer In iso_sock_rebind_bc(), the bis pointer is cached, then the socket lock is dropped: bis = iso_pi(sk)->conn->hcon; /* Release the socket before lookups since that requires hci_dev_lock * which shall not be acquired while holding sock_lock for proper * ordering. */ release_sock(sk); hci_dev_lock(bis->hdev); During the unlocked window, could a concurrent close() destroy the connection and free the bis structure, causing hci_dev_lock(bis->hdev) to access memory after it is freed, fix this by using the hdev reference which was safely acquired via iso_conn_get_hdev().

In the Linux kernel, the following vulnerability has been resolved: net: ibm: emac: Fix use-after-free during device removal The driver was using devm_register_netdev() which causes unregister_netdev() to be deferred until the devres cleanup phase, which runs after emac_remove() returns. This creates a use-after-free window where: 1. emac_remove() is called, which tears down hardware (cancels work, detaches modules, unregisters from MAL) 2. emac_remove() returns 3. devres cleanup runs and finally calls unregister_netdev() During step 3, the network stack might still process packets, triggering emac_irq(), emac_poll(), or other handlers that access now-freed hardware resources (dev->emacp, dev->mal, etc.). Fix this by replacing devm_register_netdev() with manual register_netdev() and calling unregister_netdev() at the beginning of emac_remove(), before any hardware teardown. This ensures the network device is fully stopped and unregistered before hardware resources are released. The change is safe because: - dev->ndev is assigned very early in probe (before any error paths that could bypass emac_remove) - platform_set_drvdata() is only called after successful registration, so emac_remove() only runs for fully registered devices - unregister_netdev() is idempotent and safe to call on any registered device

In the Linux kernel, the following vulnerability has been resolved: drm/xe: Fix error cleanup in xe_exec_queue_create_ioctl() Two error handling issues exist in xe_exec_queue_create_ioctl(): 1. When xe_hw_engine_group_add_exec_queue() fails, the error path jumps to put_exec_queue which skips xe_exec_queue_kill(). If the VM is in preempt fence mode, xe_vm_add_compute_exec_queue() has already added the queue to the VM's compute exec queue list. Skipping the kill leaves the queue on that list, leading to a dangling pointer after the queue is freed. 2. When xa_alloc() fails after xe_hw_engine_group_add_exec_queue() has succeeded, the error path does not call xe_hw_engine_group_del_exec_queue() to remove the queue from the hw engine group list. The queue is then freed while still linked into the hw engine group, causing a use-after-free. Fix both by: - Changing the xe_hw_engine_group_add_exec_queue() failure path to jump to kill_exec_queue so that xe_exec_queue_kill() properly removes the queue from the VM's compute list. - Adding a del_hw_engine_group label before kill_exec_queue for the xa_alloc() failure path, which removes the queue from the hw engine group before proceeding with the rest of the cleanup. (cherry picked from commit 37c831f401746a45d510b312b0ed7a77b1e06ec8)

In the Linux kernel, the following vulnerability has been resolved: xfrm: policy: fix use-after-free on inexact bin in xfrm_policy_bysel_ctx() Fix the race by pruning the bin while still holding xfrm_policy_lock, before dropping it. Use __xfrm_policy_inexact_prune_bin() directly since the lock is already held. The wrapper xfrm_policy_inexact_prune_bin() becomes unused and is removed. Race: CPU0 (XFRM_MSG_DELPOLICY) CPU1 (XFRM_MSG_NEWSPDINFO) ========================== ========================== xfrm_policy_bysel_ctx(): spin_lock_bh(xfrm_policy_lock) bin = xfrm_policy_inexact_lookup() __xfrm_policy_unlink(pol) spin_unlock_bh(xfrm_policy_lock) xfrm_policy_kill(ret) // wide window, lock not held xfrm_hash_rebuild(): spin_lock_bh(xfrm_policy_lock) __xfrm_policy_inexact_flush(): kfree_rcu(bin) // bin freed spin_unlock_bh(xfrm_policy_lock) xfrm_policy_inexact_prune_bin(bin) // UAF: bin is freed

In the Linux kernel, the following vulnerability has been resolved: netfilter: nft_tunnel: fix use-after-free on object destroy nft_tunnel_obj_destroy() calls metadata_dst_free() which directly kfree()s the metadata_dst, ignoring the dst_entry refcount. Packets that took a reference via dst_hold() in nft_tunnel_obj_eval() and are still queued (e.g. in a netem qdisc) are left with a dangling pointer. When these packets are eventually dequeued, dst_release() operates on freed memory. Replace metadata_dst_free() with dst_release() so the metadata_dst is freed only after all references are dropped. The dst subsystem already handles metadata_dst cleanup in dst_destroy() when DST_METADATA is set.

In the Linux kernel, the following vulnerability has been resolved: net: skbuff: fix missing zerocopy reference in pskb_carve helpers pskb_carve_inside_header() and pskb_carve_inside_nonlinear() both copy the old skb_shared_info header into a new buffer via memcpy(), which includes the destructor_arg pointer (uarg) for MSG_ZEROCOPY skbs. Neither function calls net_zcopy_get() for the new shinfo, creating an unaccounted holder: every skb_shared_info with destructor_arg set will call skb_zcopy_clear() once when freed, but the corresponding net_zcopy_get() was never called for the new copy. Repeated calls drive uarg->refcnt to zero prematurely, freeing ubuf_info_msgzc while TX skbs still hold live destructor_arg pointers. KASAN reports use-after-free on a freed ubuf_info_msgzc: BUG: KASAN: slab-use-after-free in skb_release_data+0x77b/0x810 Read of size 8 at addr ffff88801574d3e8 by task poc/220 Call Trace: skb_release_data+0x77b/0x810 kfree_skb_list_reason+0x13e/0x610 skb_release_data+0x4cd/0x810 sk_skb_reason_drop+0xf3/0x340 skb_queue_purge_reason+0x282/0x440 rds_tcp_inc_free+0x1e/0x30 rds_recvmsg+0x354/0x1780 __sys_recvmsg+0xdf/0x180 Allocated by task 219: msg_zerocopy_realloc+0x157/0x7b0 tcp_sendmsg_locked+0x2892/0x3ba0 Freed by task 219: ip_recv_error+0x74a/0xb10 tcp_recvmsg+0x475/0x530 The skb consuming the late access still referenced the same uarg via shinfo->destructor_arg copied by pskb_carve_inside_nonlinear() without a refcount bump. This has been verified to be reliably exploitable: a working proof-of-concept achieves full root privilege escalation from an unprivileged local user on a default kernel configuration. The fix follows the pattern of pskb_expand_head() which has the same memcpy/cloned structure. For pskb_carve_inside_header(), net_zcopy_get() is placed after skb_orphan_frags() succeeds, so the orphan error path needs no cleanup. For pskb_carve_inside_nonlinear(), net_zcopy_get() is placed after all failure points and just before skb_release_data(), so no error path needs cleanup at all -- matching pskb_expand_head() more closely and avoiding the need for a balancing net_zcopy_put().

In the Linux kernel, the following vulnerability has been resolved: net: phonet: free phonet_device after RCU grace period phonet_device_destroy() removes a phonet_device from the per-net device list with list_del_rcu(), but frees it immediately. RCU readers walking the same list can still hold a pointer to the object after it has been removed, leading to a slab-use-after-free. Use kfree_rcu(), matching the lifetime rule already used by phonet_address_del() for the same object type.

In the Linux kernel, the following vulnerability has been resolved: zram: fix use-after-free in zram_bvec_write_partial() zram_read_page() picks the sync or async backing device read path based on whether the parent bio is NULL. zram_bvec_write_partial() passes its parent bio down, so for ZRAM_WB slots the read is dispatched asynchronously and zram_read_page() returns 0 while the bio is still in flight. The caller then runs memcpy_from_bvec(), zram_write_page() and __free_page() on the buffer, leaving the async read to write into a freed page. zram_bvec_read_partial() was switched to NULL in commit 4e3c87b9421d ("zram: fix synchronous reads") for the same reason; the write_partial counterpart was missed.

In the Linux kernel, the following vulnerability has been resolved: nvmem: core: fix use-after-free bugs in error paths Fix several instances of error paths in which we call __nvmem_device_put() - which may end up freeing the underlying memory and other resources - and then keep on using the nvmem structure. Always put the reference to the nvmem device as the last step before returning the error code.

In the Linux kernel, the following vulnerability has been resolved: drm/vkms: Fix use after free and double free on init error If the driver initialization fails, the vkms_exit() function might access an uninitialized or freed default_config pointer and it might double free it. Fix both possible errors by initializing default_config only when the driver initialization succeeded.

In the Linux kernel, the following vulnerability has been resolved: bpf, sockmap: Take state lock for af_unix iter When a BPF iterator program updates a sockmap, there is a race condition in unix_stream_bpf_update_proto() where the `peer` pointer can become stale[1] during a state transition TCP_ESTABLISHED -> TCP_CLOSE. CPU0 bpf CPU1 close -------- ---------- // unix_stream_bpf_update_proto() sk_pair = unix_peer(sk) if (unlikely(!sk_pair)) return -EINVAL; // unix_release_sock() skpair = unix_peer(sk); unix_peer(sk) = NULL; sock_put(skpair) sock_hold(sk_pair) // UaF More practically, this fix guarantees that the iterator program is consistently provided with a unix socket that remains stable during iterator execution. [1]: BUG: KASAN: slab-use-after-free in unix_stream_bpf_update_proto+0x155/0x490 Write of size 4 at addr ffff8881178c9a00 by task test_progs/2231 Call Trace: dump_stack_lvl+0x5d/0x80 print_report+0x170/0x4f3 kasan_report+0xe4/0x1c0 kasan_check_range+0x125/0x200 unix_stream_bpf_update_proto+0x155/0x490 sock_map_link+0x71c/0xec0 sock_map_update_common+0xbc/0x600 sock_map_update_elem+0x19a/0x1f0 bpf_prog_bbbf56096cdd4f01_selective_dump_unix+0x20c/0x217 bpf_iter_run_prog+0x21e/0xae0 bpf_iter_unix_seq_show+0x1e0/0x2a0 bpf_seq_read+0x42c/0x10d0 vfs_read+0x171/0xb20 ksys_read+0xff/0x200 do_syscall_64+0xf7/0x5e0 entry_SYSCALL_64_after_hwframe+0x76/0x7e Allocated by task 2236: kasan_save_stack+0x30/0x50 kasan_save_track+0x14/0x30 __kasan_slab_alloc+0x63/0x80 kmem_cache_alloc_noprof+0x1d5/0x680 sk_prot_alloc+0x59/0x210 sk_alloc+0x34/0x470 unix_create1+0x86/0x8a0 unix_stream_connect+0x318/0x15b0 __sys_connect+0xfd/0x130 __x64_sys_connect+0x72/0xd0 do_syscall_64+0xf7/0x5e0 entry_SYSCALL_64_after_hwframe+0x76/0x7e Freed by task 2236: kasan_save_stack+0x30/0x50 kasan_save_track+0x14/0x30 kasan_save_free_info+0x3b/0x70 __kasan_slab_free+0x47/0x70 kmem_cache_free+0x11c/0x590 __sk_destruct+0x432/0x6e0 unix_release_sock+0x9b3/0xf60 unix_release+0x8a/0xf0 __sock_release+0xb0/0x270 sock_close+0x18/0x20 __fput+0x36e/0xac0 fput_close_sync+0xe5/0x1a0 __x64_sys_close+0x7d/0xd0 do_syscall_64+0xf7/0x5e0 entry_SYSCALL_64_after_hwframe+0x76/0x7e

In the Linux kernel, the following vulnerability has been resolved: net: ena: PHC: Fix potential use-after-free in get_timestamp Move the phc->active check and resp pointer assignment to after acquiring the spinlock. Previously, phc->active was checked without holding the lock, and resp was cached from ena_dev->phc.virt_addr before the lock was acquired. If ena_com_phc_destroy() runs between the lockless active check and the lock acquisition, it sets active=false, releases the lock, frees the DMA memory, and sets virt_addr=NULL. The get_timestamp path would then read a NULL virt_addr and dereference it. With both the active check and the pointer read under the lock, destroy cannot free the memory while get_timestamp is using it.

In the Linux kernel, the following vulnerability has been resolved: drm/xe/dma-buf: fix UAF with retry loop Retry doesn't work here, since bo will be freed on error, leading to UAF. However, now that we do the alloc & init before the attach, we can now combine this as one unit and have the init do the alloc for us. This should make the retry safe. Reported by Sashiko. v2: Fix up the error unwind (CI) (cherry picked from commit 479669418253e0f27f8cf5db01a731352ea592e7)

In the Linux kernel, the following vulnerability has been resolved: fs/mbcache: cancel shrink work before destroying the cache mb_cache_destroy() calls shrinker_free() and then frees all cache entries and the cache itself, but it does not cancel the pending c_shrink_work work item first. If mb_cache_entry_create() schedules c_shrink_work via schedule_work() and the work item is still pending or running when mb_cache_destroy() runs, mb_cache_shrink_worker() will access the cache after its memory has been freed, causing a use-after-free. This is only reachable by a privileged user (root or CAP_SYS_ADMIN) who can trigger the last put of a mounted ext2/ext4/ocfs2 filesystem. Cancel the work item with cancel_work_sync() before calling shrinker_free(), ensuring the worker has finished and will not be rescheduled before the cache is torn down.

In the Linux kernel, the following vulnerability has been resolved: mailbox: mailbox-test: free channels on probe error On probe error, free the previously obtained channels. This not only prevents a leak, but also UAF scenarios because the client structure will be removed nonetheless because it was allocated with devm.

In the Linux kernel, the following vulnerability has been resolved: ALSA: timer: Forcibly close timer instances at closing When snd_timer object is freed via snd_timer_free() and still pending snd_timer_instance objects are assigned to the timer object, it tries to unlink all instances and just set NULL to each ti->timer, then releases the resources immediately. The problem is, however, when there are slave timer instances that are associated with a master instance linked to this timer: namely, those slave instances still point to the freed timer object although the master instance is unlinked, which may lead to user-after-free. The bug can be easily triggered particularly when a new userspace-driven timers (CONFIG_SND_UTIMER) is involved, since it can create and delete the timer object via a simple file open/close, while the other applications may keep accessing to that timer. This patch is an attempt to paper over the problem above: now instead of just unlinking, call snd_timer_close[_locked]() forcibly for each pending timer instance, so that all assigned slave timer instances are properly detached, too. Since snd_timer_close() might be called later by the driver that created that instance, the check of SNDRV_TIMER_IFLG_DEAD is added at the beginning, too.

In the Linux kernel, the following vulnerability has been resolved: ice: fix double-free of tx_buf skb If ice_tso() or ice_tx_csum() fail, the error path in ice_xmit_frame_ring() frees the skb, but the 'first' tx_buf still points to it and is marked as valid (ICE_TX_BUF_SKB). 'next_to_use' remains unchanged, so the potential problem will likely fix itself when the next packet is transmitted and the tx_buf gets overwritten. But if there is no next packet and the interface is brought down instead, ice_clean_tx_ring() -> ice_unmap_and_free_tx_buf() will find the tx_buf and free the skb for the second time. The fix is to reset the tx_buf type to ICE_TX_BUF_EMPTY in the error path, so that ice_unmap_and_free_tx_buf(). Move the initialization of 'first' up, to ensure it's already valid in case we hit the linearization error path. The bug was spotted by AI while I had it looking for something else. It also proposed an initial version of the patch. I reproduced the bug and tested the fix by adding code to inject failures, on a build with KASAN. I looked for similar bugs in related Intel drivers and did not find any.

In the Linux kernel, the following vulnerability has been resolved: af_unix: Drop all SCM attributes for SOCKMAP. SOCKMAP can hide inflight fd from AF_UNIX GC. When a socket in SOCKMAP receives skb with inflight fd, sk_psock_verdict_data_ready() looks up the mapped socket and enqueue skb to its psock->ingress_skb. Since neither the old nor the new GC can inspect the psock queue, the hidden skb leaks the inflight sockets. Note that this cannot be detected via kmemleak because inflight sockets are linked to a global list. In addition, SOCKMAP redirect breaks the Tarjan-based GC's assumption that unix_edge.successor is always alive, which is no longer true once skb is redirected, resulting in use-after-free below. [0] Moreover, SOCKMAP does not call scm_stat_del() properly, so unix_show_fdinfo() could report an incorrect fd count. sk_msg_recvmsg() does not support any SCM attributes in the first place. Let's drop all SCM attributes before passing skb to the SOCKMAP layer. [0]: BUG: KASAN: slab-use-after-free in unix_del_edges (net/unix/garbage.c:118 net/unix/garbage.c:181 net/unix/garbage.c:251) Read of size 8 at addr ffff888125362670 by task kworker/56:1/496 CPU: 56 UID: 0 PID: 496 Comm: kworker/56:1 Not tainted 7.0.0-rc7-00263-gb9d8b856689d #3 PREEMPT(lazy) Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.17.0-debian-1.17.0-1 04/01/2014 Workqueue: events sk_psock_backlog Call Trace: <TASK> dump_stack_lvl (lib/dump_stack.c:122) print_report (mm/kasan/report.c:379) kasan_report (mm/kasan/report.c:597) unix_del_edges (net/unix/garbage.c:118 net/unix/garbage.c:181 net/unix/garbage.c:251) unix_destroy_fpl (net/unix/garbage.c:317) unix_destruct_scm (./include/net/scm.h:80 ./include/net/scm.h:86 net/unix/af_unix.c:1976) sk_psock_backlog (./include/linux/skbuff.h:?) process_scheduled_works (kernel/workqueue.c:?) worker_thread (kernel/workqueue.c:?) kthread (kernel/kthread.c:438) ret_from_fork (arch/x86/kernel/process.c:164) ret_from_fork_asm (arch/x86/entry/entry_64.S:258) </TASK> Allocated by task 955: kasan_save_track (mm/kasan/common.c:58 mm/kasan/common.c:78) __kasan_slab_alloc (mm/kasan/common.c:369) kmem_cache_alloc_noprof (mm/slub.c:4539) sk_prot_alloc (net/core/sock.c:2240) sk_alloc (net/core/sock.c:2301) unix_create1 (net/unix/af_unix.c:1099) unix_create (net/unix/af_unix.c:1169) __sock_create (net/socket.c:1606) __sys_socketpair (net/socket.c:1811) __x64_sys_socketpair (net/socket.c:1863 net/socket.c:1860 net/socket.c:1860) do_syscall_64 (arch/x86/entry/syscall_64.c:?) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130) Freed by task 496: kasan_save_track (mm/kasan/common.c:58 mm/kasan/common.c:78) kasan_save_free_info (mm/kasan/generic.c:587) __kasan_slab_free (mm/kasan/common.c:287) kmem_cache_free (mm/slub.c:6165) __sk_destruct (net/core/sock.c:2282 net/core/sock.c:2384) sk_psock_destroy (./include/net/sock.h:?) process_scheduled_works (kernel/workqueue.c:?) worker_thread (kernel/workqueue.c:?) kthread (kernel/kthread.c:438) ret_from_fork (arch/x86/kernel/process.c:164) ret_from_fork_asm (arch/x86/entry/entry_64.S:258)

In the Linux kernel, the following vulnerability has been resolved: media: ivsc: Fix crash at shutdown due to missing mei_cldev_disable() calls Both the ACE and CSI driver are missing a mei_cldev_disable() call in their remove() function. This causes the mei_cl client to stay part of the mei_device->file_list list even though its memory is freed by mei_cl_bus_dev_release() calling kfree(cldev->cl). This leads to a use-after-free when mei_vsc_remove() runs mei_stop() which first removes all mei bus devices calling mei_ace_remove() and mei_csi_remove() followed by mei_cl_bus_dev_release() and then calls mei_cl_all_disconnect() which walks over mei_device->file_list dereferecing the just freed cldev->cl. And mei_vsc_remove() it self is run at shutdown because of the platform_device_unregister(tp->pdev) in vsc_tp_shutdown() When building a kernel with KASAN this leads to the following KASAN report: [ 106.634504] ================================================================== [ 106.634623] BUG: KASAN: slab-use-after-free in mei_cl_set_disconnected (drivers/misc/mei/client.c:783) mei [ 106.634683] Read of size 4 at addr ffff88819cb62018 by task systemd-shutdow/1 [ 106.634729] [ 106.634767] Tainted: [E]=UNSIGNED_MODULE [ 106.634770] Hardware name: Dell Inc. XPS 16 9640/09CK4V, BIOS 1.12.0 02/10/2025 [ 106.634773] Call Trace: [ 106.634777] <TASK> ... [ 106.634871] kasan_report (mm/kasan/report.c:221 mm/kasan/report.c:636) [ 106.634901] mei_cl_set_disconnected (drivers/misc/mei/client.c:783) mei [ 106.634921] mei_cl_all_disconnect (drivers/misc/mei/client.c:2165 (discriminator 4)) mei [ 106.634941] mei_reset (drivers/misc/mei/init.c:163) mei ... [ 106.635042] mei_stop (drivers/misc/mei/init.c:348) mei [ 106.635062] mei_vsc_remove (drivers/misc/mei/mei_dev.h:784 drivers/misc/mei/platform-vsc.c:393) mei_vsc [ 106.635066] platform_remove (drivers/base/platform.c:1424) Add the missing mei_cldev_disable() calls so that the mei_cl gets removed from mei_device->file_list before it is freed to fix this.

In the Linux kernel, the following vulnerability has been resolved: HID: asus: fix UAF via HID_CLAIMED_INPUT validation After hid_hw_start() is called hidinput_connect() will eventually be called to set up the device with the input layer since the HID_CONNECT_DEFAULT connect mask is used. During hidinput_connect() all input and output reports are processed and corresponding hid_inputs are allocated and configured via hidinput_configure_usages(). This process involves slot tagging report fields and configuring usages by setting relevant bits in the capability bitmaps. However it is possible that the capability bitmaps are not set at all leading to the subsequent hidinput_has_been_populated() check to fail leading to the freeing of the hid_input and the underlying input device. This becomes problematic because a malicious HID device like a ASUS ROG N-Key keyboard can trigger the above scenario via a specially crafted descriptor which then leads to a user-after-free when the name of the freed input device is written to later on after hid_hw_start(). Below, report 93 intentionally utilises the HID_UP_UNDEFINED Usage Page which is skipped during usage configuration, leading to the frees. 0x05, 0x0D, // Usage Page (Digitizer) 0x09, 0x05, // Usage (Touch Pad) 0xA1, 0x01, // Collection (Application) 0x85, 0x0D, // Report ID (13) 0x06, 0x00, 0xFF, // Usage Page (Vendor Defined 0xFF00) 0x09, 0xC5, // Usage (0xC5) 0x15, 0x00, // Logical Minimum (0) 0x26, 0xFF, 0x00, // Logical Maximum (255) 0x75, 0x08, // Report Size (8) 0x95, 0x04, // Report Count (4) 0xB1, 0x02, // Feature (Data,Var,Abs) 0x85, 0x5D, // Report ID (93) 0x06, 0x00, 0x00, // Usage Page (Undefined) 0x09, 0x01, // Usage (0x01) 0x15, 0x00, // Logical Minimum (0) 0x26, 0xFF, 0x00, // Logical Maximum (255) 0x75, 0x08, // Report Size (8) 0x95, 0x1B, // Report Count (27) 0x81, 0x02, // Input (Data,Var,Abs) 0xC0, // End Collection Below is the KASAN splat after triggering the UAF: [ 21.672709] ================================================================== [ 21.673700] BUG: KASAN: slab-use-after-free in asus_probe+0xeeb/0xf80 [ 21.673700] Write of size 8 at addr ffff88810a0ac000 by task kworker/1:2/54 [ 21.673700] [ 21.673700] CPU: 1 UID: 0 PID: 54 Comm: kworker/1:2 Not tainted 6.16.0-rc4-g9773391cf4dd-dirty #36 PREEMPT(voluntary) [ 21.673700] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.2-debian-1.16.2-1 04/01/2014 [ 21.673700] Call Trace: [ 21.673700] <TASK> [ 21.673700] dump_stack_lvl+0x5f/0x80 [ 21.673700] print_report+0xd1/0x660 [ 21.673700] kasan_report+0xe5/0x120 [ 21.673700] __asan_report_store8_noabort+0x1b/0x30 [ 21.673700] asus_probe+0xeeb/0xf80 [ 21.673700] hid_device_probe+0x2ee/0x700 [ 21.673700] really_probe+0x1c6/0x6b0 [ 21.673700] __driver_probe_device+0x24f/0x310 [ 21.673700] driver_probe_device+0x4e/0x220 [...] [ 21.673700] [ 21.673700] Allocated by task 54: [ 21.673700] kasan_save_stack+0x3d/0x60 [ 21.673700] kasan_save_track+0x18/0x40 [ 21.673700] kasan_save_alloc_info+0x3b/0x50 [ 21.673700] __kasan_kmalloc+0x9c/0xa0 [ 21.673700] __kmalloc_cache_noprof+0x139/0x340 [ 21.673700] input_allocate_device+0x44/0x370 [ 21.673700] hidinput_connect+0xcb6/0x2630 [ 21.673700] hid_connect+0xf74/0x1d60 [ 21.673700] hid_hw_start+0x8c/0x110 [ 21.673700] asus_probe+0x5a3/0xf80 [ 21.673700] hid_device_probe+0x2ee/0x700 [ 21.673700] really_probe+0x1c6/0x6b0 [ 21.673700] __driver_probe_device+0x24f/0x310 [ 21.673700] driver_probe_device+0x4e/0x220 [...] [ 21.673700] [ 21.673700] Freed by task 54: [ 21.673700] kasan_save_stack+0x3d/0x60 [ 21.673700] kasan_save_track+0x18/0x40 [ 21.673700] kasan_save_free_info+0x3f/0x60 [ 21.673700] __kasan_slab_free+0x3c/0x50 [ 21.673700] kfre ---truncated---

In the Linux kernel, the following vulnerability has been resolved: fs/buffer: fix use-after-free when call bh_read() helper There's issue as follows: BUG: KASAN: stack-out-of-bounds in end_buffer_read_sync+0xe3/0x110 Read of size 8 at addr ffffc9000168f7f8 by task swapper/3/0 CPU: 3 UID: 0 PID: 0 Comm: swapper/3 Not tainted 6.16.0-862.14.0.6.x86_64 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996) Call Trace: <IRQ> dump_stack_lvl+0x55/0x70 print_address_description.constprop.0+0x2c/0x390 print_report+0xb4/0x270 kasan_report+0xb8/0xf0 end_buffer_read_sync+0xe3/0x110 end_bio_bh_io_sync+0x56/0x80 blk_update_request+0x30a/0x720 scsi_end_request+0x51/0x2b0 scsi_io_completion+0xe3/0x480 ? scsi_device_unbusy+0x11e/0x160 blk_complete_reqs+0x7b/0x90 handle_softirqs+0xef/0x370 irq_exit_rcu+0xa5/0xd0 sysvec_apic_timer_interrupt+0x6e/0x90 </IRQ> Above issue happens when do ntfs3 filesystem mount, issue may happens as follows: mount IRQ ntfs_fill_super read_cache_page do_read_cache_folio filemap_read_folio mpage_read_folio do_mpage_readpage ntfs_get_block_vbo bh_read submit_bh wait_on_buffer(bh); blk_complete_reqs scsi_io_completion scsi_end_request blk_update_request end_bio_bh_io_sync end_buffer_read_sync __end_buffer_read_notouch unlock_buffer wait_on_buffer(bh);--> return will return to caller put_bh --> trigger stack-out-of-bounds In the mpage_read_folio() function, the stack variable 'map_bh' is passed to ntfs_get_block_vbo(). Once unlock_buffer() unlocks and wait_on_buffer() returns to continue processing, the stack variable is likely to be reclaimed. Consequently, during the end_buffer_read_sync() process, calling put_bh() may result in stack overrun. If the bh is not allocated on the stack, it belongs to a folio. Freeing a buffer head which belongs to a folio is done by drop_buffers() which will fail to free buffers which are still locked. So it is safe to call put_bh() before __end_buffer_read_notouch().

In the Linux kernel, the following vulnerability has been resolved: net: appletalk: Fix use-after-free in AARP proxy probe The AARP proxy‐probe routine (aarp_proxy_probe_network) sends a probe, releases the aarp_lock, sleeps, then re-acquires the lock. During that window an expire timer thread (__aarp_expire_timer) can remove and kfree() the same entry, leading to a use-after-free. race condition: cpu 0 | cpu 1 atalk_sendmsg() | atif_proxy_probe_device() aarp_send_ddp() | aarp_proxy_probe_network() mod_timer() | lock(aarp_lock) // LOCK!! timeout around 200ms | alloc(aarp_entry) and then call | proxies[hash] = aarp_entry aarp_expire_timeout() | aarp_send_probe() | unlock(aarp_lock) // UNLOCK!! lock(aarp_lock) // LOCK!! | msleep(100); __aarp_expire_timer(&proxies[ct]) | free(aarp_entry) | unlock(aarp_lock) // UNLOCK!! | | lock(aarp_lock) // LOCK!! | UAF aarp_entry !! ================================================================== BUG: KASAN: slab-use-after-free in aarp_proxy_probe_network+0x560/0x630 net/appletalk/aarp.c:493 Read of size 4 at addr ffff8880123aa360 by task repro/13278 CPU: 3 UID: 0 PID: 13278 Comm: repro Not tainted 6.15.2 #3 PREEMPT(full) Call Trace: <TASK> __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1b0 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:408 [inline] print_report+0xc1/0x630 mm/kasan/report.c:521 kasan_report+0xca/0x100 mm/kasan/report.c:634 aarp_proxy_probe_network+0x560/0x630 net/appletalk/aarp.c:493 atif_proxy_probe_device net/appletalk/ddp.c:332 [inline] atif_ioctl+0xb58/0x16c0 net/appletalk/ddp.c:857 atalk_ioctl+0x198/0x2f0 net/appletalk/ddp.c:1818 sock_do_ioctl+0xdc/0x260 net/socket.c:1190 sock_ioctl+0x239/0x6a0 net/socket.c:1311 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:906 [inline] __se_sys_ioctl fs/ioctl.c:892 [inline] __x64_sys_ioctl+0x194/0x200 fs/ioctl.c:892 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcb/0x250 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f </TASK> Allocated: aarp_alloc net/appletalk/aarp.c:382 [inline] aarp_proxy_probe_network+0xd8/0x630 net/appletalk/aarp.c:468 atif_proxy_probe_device net/appletalk/ddp.c:332 [inline] atif_ioctl+0xb58/0x16c0 net/appletalk/ddp.c:857 atalk_ioctl+0x198/0x2f0 net/appletalk/ddp.c:1818 Freed: kfree+0x148/0x4d0 mm/slub.c:4841 __aarp_expire net/appletalk/aarp.c:90 [inline] __aarp_expire_timer net/appletalk/aarp.c:261 [inline] aarp_expire_timeout+0x480/0x6e0 net/appletalk/aarp.c:317 The buggy address belongs to the object at ffff8880123aa300 which belongs to the cache kmalloc-192 of size 192 The buggy address is located 96 bytes inside of freed 192-byte region [ffff8880123aa300, ffff8880123aa3c0) Memory state around the buggy address: ffff8880123aa200: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff8880123aa280: 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc fc >ffff8880123aa300: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880123aa380: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ffff8880123aa400: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ==================================================================

In the Linux kernel, the following vulnerability has been resolved: ftrace: Also allocate and copy hash for reading of filter files Currently the reader of set_ftrace_filter and set_ftrace_notrace just adds the pointer to the global tracer hash to its iterator. Unlike the writer that allocates a copy of the hash, the reader keeps the pointer to the filter hashes. This is problematic because this pointer is static across function calls that release the locks that can update the global tracer hashes. This can cause UAF and similar bugs. Allocate and copy the hash for reading the filter files like it is done for the writers. This not only fixes UAF bugs, but also makes the code a bit simpler as it doesn't have to differentiate when to free the iterator's hash between writers and readers.

In the Linux kernel, the following vulnerability has been resolved: serial: caif: fix use-after-free in caif_serial ldisc_close() There is a use-after-free bug in caif_serial where handle_tx() may access ser->tty after the tty has been freed. The race condition occurs between ldisc_close() and packet transmission: CPU 0 (close) CPU 1 (xmit) ------------- ------------ ldisc_close() tty_kref_put(ser->tty) [tty may be freed here] <-- race window --> caif_xmit() handle_tx() tty = ser->tty // dangling ptr tty->ops->write() // UAF! schedule_work() ser_release() unregister_netdevice() The root cause is that tty_kref_put() is called in ldisc_close() while the network device is still active and can receive packets. Since ser and tty have a 1:1 binding relationship with consistent lifecycles (ser is allocated in ldisc_open and freed in ser_release via unregister_netdevice, and each ser binds exactly one tty), we can safely defer the tty reference release to ser_release() where the network device is unregistered. Fix this by moving tty_kref_put() from ldisc_close() to ser_release(), after unregister_netdevice(). This ensures the tty reference is held as long as the network device exists, preventing the UAF. Note: We save ser->tty before unregister_netdevice() because ser is embedded in netdev's private data and will be freed along with netdev (needs_free_netdev = true). How to reproduce: Add mdelay(500) at the beginning of ldisc_close() to widen the race window, then run the reproducer program [1]. Note: There is a separate deadloop issue in handle_tx() when using PORT_UNKNOWN serial ports (e.g., /dev/ttyS3 in QEMU without proper serial backend). This deadloop exists even without this patch, and is likely caused by inconsistency between uart_write_room() and uart_write() in serial core. It has been addressed in a separate patch [2]. KASAN report: ================================================================== BUG: KASAN: slab-use-after-free in handle_tx+0x5d1/0x620 Read of size 1 at addr ffff8881131e1490 by task caif_uaf_trigge/9929 Call Trace: <TASK> dump_stack_lvl+0x10e/0x1f0 print_report+0xd0/0x630 kasan_report+0xe4/0x120 handle_tx+0x5d1/0x620 dev_hard_start_xmit+0x9d/0x6c0 __dev_queue_xmit+0x6e2/0x4410 packet_xmit+0x243/0x360 packet_sendmsg+0x26cf/0x5500 __sys_sendto+0x4a3/0x520 __x64_sys_sendto+0xe0/0x1c0 do_syscall_64+0xc9/0xf80 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f615df2c0d7 Allocated by task 9930: Freed by task 64: Last potentially related work creation: The buggy address belongs to the object at ffff8881131e1000 which belongs to the cache kmalloc-cg-2k of size 2048 The buggy address is located 1168 bytes inside of freed 2048-byte region [ffff8881131e1000, ffff8881131e1800) The buggy address belongs to the physical page: page_owner tracks the page as allocated page last free pid 9778 tgid 9778 stack trace: Memory state around the buggy address: ffff8881131e1380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881131e1400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8881131e1480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8881131e1500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881131e1580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== [1]: https://gist.github.com/mrpre/f683f244544f7b11e7fa87df9e6c2eeb [2]: https://lore.kernel.org/linux-serial/20260204074327.226165-1-jiayuan.chen@linux.dev/T/#u