In the Linux kernel, the following vulnerability has been resolved: kcm: Serialise kcm_sendmsg() for the same socket. syzkaller reported UAF in kcm_release(). [0] The scenario is 1. Thread A builds a skb with MSG_MORE and sets kcm->seq_skb. 2. Thread A resumes building skb from kcm->seq_skb but is blocked by sk_stream_wait_memory() 3. Thread B calls sendmsg() concurrently, finishes building kcm->seq_skb and puts the skb to the write queue 4. Thread A faces an error and finally frees skb that is already in the write queue 5. kcm_release() does double-free the skb in the write queue When a thread is building a MSG_MORE skb, another thread must not touch it. Let's add a per-sk mutex and serialise kcm_sendmsg(). [0]: BUG: KASAN: slab-use-after-free in __skb_unlink include/linux/skbuff.h:2366 [inline] BUG: KASAN: slab-use-after-free in __skb_dequeue include/linux/skbuff.h:2385 [inline] BUG: KASAN: slab-use-after-free in __skb_queue_purge_reason include/linux/skbuff.h:3175 [inline] BUG: KASAN: slab-use-after-free in __skb_queue_purge include/linux/skbuff.h:3181 [inline] BUG: KASAN: slab-use-after-free in kcm_release+0x170/0x4c8 net/kcm/kcmsock.c:1691 Read of size 8 at addr ffff0000ced0fc80 by task syz-executor329/6167 CPU: 1 PID: 6167 Comm: syz-executor329 Tainted: G B 6.8.0-rc5-syzkaller-g9abbc24128bc #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024 Call trace: dump_backtrace+0x1b8/0x1e4 arch/arm64/kernel/stacktrace.c:291 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:298 __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xd0/0x124 lib/dump_stack.c:106 print_address_description mm/kasan/report.c:377 [inline] print_report+0x178/0x518 mm/kasan/report.c:488 kasan_report+0xd8/0x138 mm/kasan/report.c:601 __asan_report_load8_noabort+0x20/0x2c mm/kasan/report_generic.c:381 __skb_unlink include/linux/skbuff.h:2366 [inline] __skb_dequeue include/linux/skbuff.h:2385 [inline] __skb_queue_purge_reason include/linux/skbuff.h:3175 [inline] __skb_queue_purge include/linux/skbuff.h:3181 [inline] kcm_release+0x170/0x4c8 net/kcm/kcmsock.c:1691 __sock_release net/socket.c:659 [inline] sock_close+0xa4/0x1e8 net/socket.c:1421 __fput+0x30c/0x738 fs/file_table.c:376 ____fput+0x20/0x30 fs/file_table.c:404 task_work_run+0x230/0x2e0 kernel/task_work.c:180 exit_task_work include/linux/task_work.h:38 [inline] do_exit+0x618/0x1f64 kernel/exit.c:871 do_group_exit+0x194/0x22c kernel/exit.c:1020 get_signal+0x1500/0x15ec kernel/signal.c:2893 do_signal+0x23c/0x3b44 arch/arm64/kernel/signal.c:1249 do_notify_resume+0x74/0x1f4 arch/arm64/kernel/entry-common.c:148 exit_to_user_mode_prepare arch/arm64/kernel/entry-common.c:169 [inline] exit_to_user_mode arch/arm64/kernel/entry-common.c:178 [inline] el0_svc+0xac/0x168 arch/arm64/kernel/entry-common.c:713 el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:730 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:598 Allocated by task 6166: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x40/0x78 mm/kasan/common.c:68 kasan_save_alloc_info+0x70/0x84 mm/kasan/generic.c:626 unpoison_slab_object mm/kasan/common.c:314 [inline] __kasan_slab_alloc+0x74/0x8c mm/kasan/common.c:340 kasan_slab_alloc include/linux/kasan.h:201 [inline] slab_post_alloc_hook mm/slub.c:3813 [inline] slab_alloc_node mm/slub.c:3860 [inline] kmem_cache_alloc_node+0x204/0x4c0 mm/slub.c:3903 __alloc_skb+0x19c/0x3d8 net/core/skbuff.c:641 alloc_skb include/linux/skbuff.h:1296 [inline] kcm_sendmsg+0x1d3c/0x2124 net/kcm/kcmsock.c:783 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg net/socket.c:745 [inline] sock_sendmsg+0x220/0x2c0 net/socket.c:768 splice_to_socket+0x7cc/0xd58 fs/splice.c:889 do_splice_from fs/splice.c:941 [inline] direct_splice_actor+0xec/0x1d8 fs/splice.c:1164 splice_direct_to_actor+0x438/0xa0c fs/splice.c:1108 do_splice_direct_actor ---truncated---

Use after free in some Intel(R) Aptio* V UEFI Firmware Integrator Tools may allowed an authenticated user to potentially enable denial of service via local access.

In the Linux kernel, the following vulnerability has been resolved: netem: fix return value if duplicate enqueue fails There is a bug in netem_enqueue() introduced by commit 5845f706388a ("net: netem: fix skb length BUG_ON in __skb_to_sgvec") that can lead to a use-after-free. This commit made netem_enqueue() always return NET_XMIT_SUCCESS when a packet is duplicated, which can cause the parent qdisc's q.qlen to be mistakenly incremented. When this happens qlen_notify() may be skipped on the parent during destruction, leaving a dangling pointer for some classful qdiscs like DRR. There are two ways for the bug happen: - If the duplicated packet is dropped by rootq->enqueue() and then the original packet is also dropped. - If rootq->enqueue() sends the duplicated packet to a different qdisc and the original packet is dropped. In both cases NET_XMIT_SUCCESS is returned even though no packets are enqueued at the netem qdisc. The fix is to defer the enqueue of the duplicate packet until after the original packet has been guaranteed to return NET_XMIT_SUCCESS.

In the Linux kernel, the following vulnerability has been resolved: net: rswitch: Avoid use-after-free in rswitch_poll() The use-after-free is actually in rswitch_tx_free(), which is inlined in rswitch_poll(). Since `skb` and `gq->skbs[gq->dirty]` are in fact the same pointer, the skb is first freed using dev_kfree_skb_any(), then the value in skb->len is used to update the interface statistics. Let's move around the instructions to use skb->len before the skb is freed. This bug is trivial to reproduce using KFENCE. It will trigger a splat every few packets. A simple ARP request or ICMP echo request is enough.

In the Linux kernel, the following vulnerability has been resolved: libceph: fix race between delayed_work() and ceph_monc_stop() The way the delayed work is handled in ceph_monc_stop() is prone to races with mon_fault() and possibly also finish_hunting(). Both of these can requeue the delayed work which wouldn't be canceled by any of the following code in case that happens after cancel_delayed_work_sync() runs -- __close_session() doesn't mess with the delayed work in order to avoid interfering with the hunting interval logic. This part was missed in commit b5d91704f53e ("libceph: behave in mon_fault() if cur_mon < 0") and use-after-free can still ensue on monc and objects that hang off of it, with monc->auth and monc->monmap being particularly susceptible to quickly being reused. To fix this: - clear monc->cur_mon and monc->hunting as part of closing the session in ceph_monc_stop() - bail from delayed_work() if monc->cur_mon is cleared, similar to how it's done in mon_fault() and finish_hunting() (based on monc->hunting) - call cancel_delayed_work_sync() after the session is closed

In the Linux kernel, the following vulnerability has been resolved: thermal/debugfs: Prevent use-after-free from occurring after cdev removal Since thermal_debug_cdev_remove() does not run under cdev->lock, it can run in parallel with thermal_debug_cdev_state_update() and it may free the struct thermal_debugfs object used by the latter after it has been checked against NULL. If that happens, thermal_debug_cdev_state_update() will access memory that has been freed already causing the kernel to crash. Address this by using cdev->lock in thermal_debug_cdev_remove() around the cdev->debugfs value check (in case the same cdev is removed at the same time in two different threads) and its reset to NULL. Cc :6.8+ <stable@vger.kernel.org> # 6.8+

In the Linux kernel, the following vulnerability has been resolved: wifi: brcmfmac: Fix use-after-free bug in brcmf_cfg80211_detach This is the candidate patch of CVE-2023-47233 : https://nvd.nist.gov/vuln/detail/CVE-2023-47233 In brcm80211 driver,it starts with the following invoking chain to start init a timeout worker: ->brcmf_usb_probe ->brcmf_usb_probe_cb ->brcmf_attach ->brcmf_bus_started ->brcmf_cfg80211_attach ->wl_init_priv ->brcmf_init_escan ->INIT_WORK(&cfg->escan_timeout_work, brcmf_cfg80211_escan_timeout_worker); If we disconnect the USB by hotplug, it will call brcmf_usb_disconnect to make cleanup. The invoking chain is : brcmf_usb_disconnect ->brcmf_usb_disconnect_cb ->brcmf_detach ->brcmf_cfg80211_detach ->kfree(cfg); While the timeout woker may still be running. This will cause a use-after-free bug on cfg in brcmf_cfg80211_escan_timeout_worker. Fix it by deleting the timer and canceling the worker in brcmf_cfg80211_detach. [arend.vanspriel@broadcom.com: keep timer delete as is and cancel work just before free]

In the Linux kernel, the following vulnerability has been resolved: nilfs2: fix potential use after free in nilfs_gccache_submit_read_data() In nilfs_gccache_submit_read_data(), brelse(bh) is called to drop the reference count of bh when the call to nilfs_dat_translate() fails. If the reference count hits 0 and its owner page gets unlocked, bh may be freed. However, bh->b_page is dereferenced to put the page after that, which may result in a use-after-free bug. This patch moves the release operation after unlocking and putting the page. NOTE: The function in question is only called in GC, and in combination with current userland tools, address translation using DAT does not occur in that function, so the code path that causes this issue will not be executed. However, it is possible to run that code path by intentionally modifying the userland GC library or by calling the GC ioctl directly. [konishi.ryusuke@gmail.com: NOTE added to the commit log]

There are use-after-free vulnerabilities caused by timer handler in net/rose/rose_timer.c of linux that allow attackers to crash linux kernel without any privileges.

In the Linux kernel, the following vulnerability has been resolved: bpf: Fix racing between bpf_timer_cancel_and_free and bpf_timer_cancel The following race is possible between bpf_timer_cancel_and_free and bpf_timer_cancel. It will lead a UAF on the timer->timer. bpf_timer_cancel(); spin_lock(); t = timer->time; spin_unlock(); bpf_timer_cancel_and_free(); spin_lock(); t = timer->timer; timer->timer = NULL; spin_unlock(); hrtimer_cancel(&t->timer); kfree(t); /* UAF on t */ hrtimer_cancel(&t->timer); In bpf_timer_cancel_and_free, this patch frees the timer->timer after a rcu grace period. This requires a rcu_head addition to the "struct bpf_hrtimer". Another kfree(t) happens in bpf_timer_init, this does not need a kfree_rcu because it is still under the spin_lock and timer->timer has not been visible by others yet. In bpf_timer_cancel, rcu_read_lock() is added because this helper can be used in a non rcu critical section context (e.g. from a sleepable bpf prog). Other timer->timer usages in helpers.c have been audited, bpf_timer_cancel() is the only place where timer->timer is used outside of the spin_lock. Another solution considered is to mark a t->flag in bpf_timer_cancel and clear it after hrtimer_cancel() is done. In bpf_timer_cancel_and_free, it busy waits for the flag to be cleared before kfree(t). This patch goes with a straight forward solution and frees timer->timer after a rcu grace period.

A use-after-free flaw was found in fs/ext4/namei.c:dx_insert_block() in the Linux kernel’s filesystem sub-component. This flaw allows a local attacker with a user privilege to cause a denial of service.

A NULL pointer dereference flaw was found in the Linux kernel’s X.25 set of standardized network protocols functionality in the way a user terminates their session using a simulated Ethernet card and continued usage of this connection. This flaw allows a local user to crash the system.

A use-after-free vulnerabilitity was discovered in drivers/net/hamradio/6pack.c of linux that allows an attacker to crash linux kernel by simulating ax25 device using 6pack driver from user space.

A use-after-free vulnerability was found in the Linux kernel in drivers/net/hamradio. This flaw allows a local attacker with a user privilege to cause a denial of service (DOS) when the mkiss or sixpack device is detached and reclaim resources early.

An issue was discovered in the Linux kernel through 6.4.2. A crafted UDF filesystem image causes a use-after-free write operation in the udf_put_super and udf_close_lvid functions in fs/udf/super.c. NOTE: the suse.com reference has a different perspective about this.

In the Linux kernel, the following vulnerability has been resolved: sched/fair: Prevent dead task groups from regaining cfs_rq's Kevin is reporting crashes which point to a use-after-free of a cfs_rq in update_blocked_averages(). Initial debugging revealed that we've live cfs_rq's (on_list=1) in an about to be kfree()'d task group in free_fair_sched_group(). However, it was unclear how that can happen. His kernel config happened to lead to a layout of struct sched_entity that put the 'my_q' member directly into the middle of the object which makes it incidentally overlap with SLUB's freelist pointer. That, in combination with SLAB_FREELIST_HARDENED's freelist pointer mangling, leads to a reliable access violation in form of a #GP which made the UAF fail fast. Michal seems to have run into the same issue[1]. He already correctly diagnosed that commit a7b359fc6a37 ("sched/fair: Correctly insert cfs_rq's to list on unthrottle") is causing the preconditions for the UAF to happen by re-adding cfs_rq's also to task groups that have no more running tasks, i.e. also to dead ones. His analysis, however, misses the real root cause and it cannot be seen from the crash backtrace only, as the real offender is tg_unthrottle_up() getting called via sched_cfs_period_timer() via the timer interrupt at an inconvenient time. When unregister_fair_sched_group() unlinks all cfs_rq's from the dying task group, it doesn't protect itself from getting interrupted. If the timer interrupt triggers while we iterate over all CPUs or after unregister_fair_sched_group() has finished but prior to unlinking the task group, sched_cfs_period_timer() will execute and walk the list of task groups, trying to unthrottle cfs_rq's, i.e. re-add them to the dying task group. These will later -- in free_fair_sched_group() -- be kfree()'ed while still being linked, leading to the fireworks Kevin and Michal are seeing. To fix this race, ensure the dying task group gets unlinked first. However, simply switching the order of unregistering and unlinking the task group isn't sufficient, as concurrent RCU walkers might still see it, as can be seen below: CPU1: CPU2: : timer IRQ: : do_sched_cfs_period_timer(): : : : distribute_cfs_runtime(): : rcu_read_lock(); : : : unthrottle_cfs_rq(): sched_offline_group(): : : walk_tg_tree_from(…,tg_unthrottle_up,…): list_del_rcu(&tg->list); : (1) : list_for_each_entry_rcu(child, &parent->children, siblings) : : (2) list_del_rcu(&tg->siblings); : : tg_unthrottle_up(): unregister_fair_sched_group(): struct cfs_rq *cfs_rq = tg->cfs_rq[cpu_of(rq)]; : : list_del_leaf_cfs_rq(tg->cfs_rq[cpu]); : : : : if (!cfs_rq_is_decayed(cfs_rq) || cfs_rq->nr_running) (3) : list_add_leaf_cfs_rq(cfs_rq); : : : : : : : : : ---truncated---

In the Linux kernel, the following vulnerability has been resolved: ipmi: Fix UAF when uninstall ipmi_si and ipmi_msghandler module Hi, When testing install and uninstall of ipmi_si.ko and ipmi_msghandler.ko, the system crashed. The log as follows: [ 141.087026] BUG: unable to handle kernel paging request at ffffffffc09b3a5a [ 141.087241] PGD 8fe4c0d067 P4D 8fe4c0d067 PUD 8fe4c0f067 PMD 103ad89067 PTE 0 [ 141.087464] Oops: 0010 [#1] SMP NOPTI [ 141.087580] CPU: 67 PID: 668 Comm: kworker/67:1 Kdump: loaded Not tainted 4.18.0.x86_64 #47 [ 141.088009] Workqueue: events 0xffffffffc09b3a40 [ 141.088009] RIP: 0010:0xffffffffc09b3a5a [ 141.088009] Code: Bad RIP value. [ 141.088009] RSP: 0018:ffffb9094e2c3e88 EFLAGS: 00010246 [ 141.088009] RAX: 0000000000000000 RBX: ffff9abfdb1f04a0 RCX: 0000000000000000 [ 141.088009] RDX: 0000000000000000 RSI: 0000000000000246 RDI: 0000000000000246 [ 141.088009] RBP: 0000000000000000 R08: ffff9abfffee3cb8 R09: 00000000000002e1 [ 141.088009] R10: ffffb9094cb73d90 R11: 00000000000f4240 R12: ffff9abfffee8700 [ 141.088009] R13: 0000000000000000 R14: ffff9abfdb1f04a0 R15: ffff9abfdb1f04a8 [ 141.088009] FS: 0000000000000000(0000) GS:ffff9abfffec0000(0000) knlGS:0000000000000000 [ 141.088009] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 141.088009] CR2: ffffffffc09b3a30 CR3: 0000008fe4c0a001 CR4: 00000000007606e0 [ 141.088009] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 141.088009] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 141.088009] PKRU: 55555554 [ 141.088009] Call Trace: [ 141.088009] ? process_one_work+0x195/0x390 [ 141.088009] ? worker_thread+0x30/0x390 [ 141.088009] ? process_one_work+0x390/0x390 [ 141.088009] ? kthread+0x10d/0x130 [ 141.088009] ? kthread_flush_work_fn+0x10/0x10 [ 141.088009] ? ret_from_fork+0x35/0x40] BUG: unable to handle kernel paging request at ffffffffc0b28a5a [ 200.223240] PGD 97fe00d067 P4D 97fe00d067 PUD 97fe00f067 PMD a580cbf067 PTE 0 [ 200.223464] Oops: 0010 [#1] SMP NOPTI [ 200.223579] CPU: 63 PID: 664 Comm: kworker/63:1 Kdump: loaded Not tainted 4.18.0.x86_64 #46 [ 200.224008] Workqueue: events 0xffffffffc0b28a40 [ 200.224008] RIP: 0010:0xffffffffc0b28a5a [ 200.224008] Code: Bad RIP value. [ 200.224008] RSP: 0018:ffffbf3c8e2a3e88 EFLAGS: 00010246 [ 200.224008] RAX: 0000000000000000 RBX: ffffa0799ad6bca0 RCX: 0000000000000000 [ 200.224008] RDX: 0000000000000000 RSI: 0000000000000246 RDI: 0000000000000246 [ 200.224008] RBP: 0000000000000000 R08: ffff9fe43fde3cb8 R09: 00000000000000d5 [ 200.224008] R10: ffffbf3c8cb53d90 R11: 00000000000f4240 R12: ffff9fe43fde8700 [ 200.224008] R13: 0000000000000000 R14: ffffa0799ad6bca0 R15: ffffa0799ad6bca8 [ 200.224008] FS: 0000000000000000(0000) GS:ffff9fe43fdc0000(0000) knlGS:0000000000000000 [ 200.224008] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 200.224008] CR2: ffffffffc0b28a30 CR3: 00000097fe00a002 CR4: 00000000007606e0 [ 200.224008] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 200.224008] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 200.224008] PKRU: 55555554 [ 200.224008] Call Trace: [ 200.224008] ? process_one_work+0x195/0x390 [ 200.224008] ? worker_thread+0x30/0x390 [ 200.224008] ? process_one_work+0x390/0x390 [ 200.224008] ? kthread+0x10d/0x130 [ 200.224008] ? kthread_flush_work_fn+0x10/0x10 [ 200.224008] ? ret_from_fork+0x35/0x40 [ 200.224008] kernel fault(0x1) notification starting on CPU 63 [ 200.224008] kernel fault(0x1) notification finished on CPU 63 [ 200.224008] CR2: ffffffffc0b28a5a [ 200.224008] ---[ end trace c82a412d93f57412 ]--- The reason is as follows: T1: rmmod ipmi_si. ->ipmi_unregister_smi() -> ipmi_bmc_unregister() -> __ipmi_bmc_unregister() -> kref_put(&bmc->usecount, cleanup_bmc_device); -> schedule_work(&bmc->remove_work); T2: rmmod ipmi_msghandl ---truncated---

In the Linux kernel, the following vulnerability has been resolved: drm/amdgpu: Fix a use-after-free looks like we forget to set ttm->sg to NULL. Hit panic below [ 1235.844104] general protection fault, probably for non-canonical address 0x6b6b6b6b6b6b7b4b: 0000 [#1] SMP DEBUG_PAGEALLOC NOPTI [ 1235.989074] Call Trace: [ 1235.991751] sg_free_table+0x17/0x20 [ 1235.995667] amdgpu_ttm_backend_unbind.cold+0x4d/0xf7 [amdgpu] [ 1236.002288] amdgpu_ttm_backend_destroy+0x29/0x130 [amdgpu] [ 1236.008464] ttm_tt_destroy+0x1e/0x30 [ttm] [ 1236.013066] ttm_bo_cleanup_memtype_use+0x51/0xa0 [ttm] [ 1236.018783] ttm_bo_release+0x262/0xa50 [ttm] [ 1236.023547] ttm_bo_put+0x82/0xd0 [ttm] [ 1236.027766] amdgpu_bo_unref+0x26/0x50 [amdgpu] [ 1236.032809] amdgpu_amdkfd_gpuvm_alloc_memory_of_gpu+0x7aa/0xd90 [amdgpu] [ 1236.040400] kfd_ioctl_alloc_memory_of_gpu+0xe2/0x330 [amdgpu] [ 1236.046912] kfd_ioctl+0x463/0x690 [amdgpu]

In the Linux kernel, the following vulnerability has been resolved: f2fs: fix to avoid racing on fsync_entry_slab by multi filesystem instances As syzbot reported, there is an use-after-free issue during f2fs recovery: Use-after-free write at 0xffff88823bc16040 (in kfence-#10): kmem_cache_destroy+0x1f/0x120 mm/slab_common.c:486 f2fs_recover_fsync_data+0x75b0/0x8380 fs/f2fs/recovery.c:869 f2fs_fill_super+0x9393/0xa420 fs/f2fs/super.c:3945 mount_bdev+0x26c/0x3a0 fs/super.c:1367 legacy_get_tree+0xea/0x180 fs/fs_context.c:592 vfs_get_tree+0x86/0x270 fs/super.c:1497 do_new_mount fs/namespace.c:2905 [inline] path_mount+0x196f/0x2be0 fs/namespace.c:3235 do_mount fs/namespace.c:3248 [inline] __do_sys_mount fs/namespace.c:3456 [inline] __se_sys_mount+0x2f9/0x3b0 fs/namespace.c:3433 do_syscall_64+0x3f/0xb0 arch/x86/entry/common.c:47 entry_SYSCALL_64_after_hwframe+0x44/0xae The root cause is multi f2fs filesystem instances can race on accessing global fsync_entry_slab pointer, result in use-after-free issue of slab cache, fixes to init/destroy this slab cache only once during module init/destroy procedure to avoid this issue.

In the Linux kernel, the following vulnerability has been resolved: userfaultfd: release page in error path to avoid BUG_ON Consider the following sequence of events: 1. Userspace issues a UFFD ioctl, which ends up calling into shmem_mfill_atomic_pte(). We successfully account the blocks, we shmem_alloc_page(), but then the copy_from_user() fails. We return -ENOENT. We don't release the page we allocated. 2. Our caller detects this error code, tries the copy_from_user() after dropping the mmap_lock, and retries, calling back into shmem_mfill_atomic_pte(). 3. Meanwhile, let's say another process filled up the tmpfs being used. 4. So shmem_mfill_atomic_pte() fails to account blocks this time, and immediately returns - without releasing the page. This triggers a BUG_ON in our caller, which asserts that the page should always be consumed, unless -ENOENT is returned. To fix this, detect if we have such a "dangling" page when accounting fails, and if so, release it before returning.

In the Linux kernel, the following vulnerability has been resolved: usb: gadget: f_fs: Clear ffs_eventfd in ffs_data_clear. ffs_data_clear is indirectly called from both ffs_fs_kill_sb and ffs_ep0_release, so it ends up being called twice when userland closes ep0 and then unmounts f_fs. If userland provided an eventfd along with function's USB descriptors, it ends up calling eventfd_ctx_put as many times, causing a refcount underflow. NULL-ify ffs_eventfd to prevent these extraneous eventfd_ctx_put calls. Also, set epfiles to NULL right after de-allocating it, for readability. For completeness, ffs_data_clear actually ends up being called thrice, the last call being before the whole ffs structure gets freed, so when this specific sequence happens there is a second underflow happening (but not being reported): /sys/kernel/debug/tracing# modprobe usb_f_fs /sys/kernel/debug/tracing# echo ffs_data_clear > set_ftrace_filter /sys/kernel/debug/tracing# echo function > current_tracer /sys/kernel/debug/tracing# echo 1 > tracing_on (setup gadget, run and kill function userland process, teardown gadget) /sys/kernel/debug/tracing# echo 0 > tracing_on /sys/kernel/debug/tracing# cat trace smartcard-openp-436 [000] ..... 1946.208786: ffs_data_clear <-ffs_data_closed smartcard-openp-431 [000] ..... 1946.279147: ffs_data_clear <-ffs_data_closed smartcard-openp-431 [000] .n... 1946.905512: ffs_data_clear <-ffs_data_put Warning output corresponding to above trace: [ 1946.284139] WARNING: CPU: 0 PID: 431 at lib/refcount.c:28 refcount_warn_saturate+0x110/0x15c [ 1946.293094] refcount_t: underflow; use-after-free. [ 1946.298164] Modules linked in: usb_f_ncm(E) u_ether(E) usb_f_fs(E) hci_uart(E) btqca(E) btrtl(E) btbcm(E) btintel(E) bluetooth(E) nls_ascii(E) nls_cp437(E) vfat(E) fat(E) bcm2835_v4l2(CE) bcm2835_mmal_vchiq(CE) videobuf2_vmalloc(E) videobuf2_memops(E) sha512_generic(E) videobuf2_v4l2(E) sha512_arm(E) videobuf2_common(E) videodev(E) cpufreq_dt(E) snd_bcm2835(CE) brcmfmac(E) mc(E) vc4(E) ctr(E) brcmutil(E) snd_soc_core(E) snd_pcm_dmaengine(E) drbg(E) snd_pcm(E) snd_timer(E) snd(E) soundcore(E) drm_kms_helper(E) cec(E) ansi_cprng(E) rc_core(E) syscopyarea(E) raspberrypi_cpufreq(E) sysfillrect(E) sysimgblt(E) cfg80211(E) max17040_battery(OE) raspberrypi_hwmon(E) fb_sys_fops(E) regmap_i2c(E) ecdh_generic(E) rfkill(E) ecc(E) bcm2835_rng(E) rng_core(E) vchiq(CE) leds_gpio(E) libcomposite(E) fuse(E) configfs(E) ip_tables(E) x_tables(E) autofs4(E) ext4(E) crc16(E) mbcache(E) jbd2(E) crc32c_generic(E) sdhci_iproc(E) sdhci_pltfm(E) sdhci(E) [ 1946.399633] CPU: 0 PID: 431 Comm: smartcard-openp Tainted: G C OE 5.15.0-1-rpi #1 Debian 5.15.3-1 [ 1946.417950] Hardware name: BCM2835 [ 1946.425442] Backtrace: [ 1946.432048] [<c08d60a0>] (dump_backtrace) from [<c08d62ec>] (show_stack+0x20/0x24) [ 1946.448226] r7:00000009 r6:0000001c r5:c04a948c r4:c0a64e2c [ 1946.458412] [<c08d62cc>] (show_stack) from [<c08d9ae0>] (dump_stack+0x28/0x30) [ 1946.470380] [<c08d9ab8>] (dump_stack) from [<c0123500>] (__warn+0xe8/0x154) [ 1946.482067] r5:c04a948c r4:c0a71dc8 [ 1946.490184] [<c0123418>] (__warn) from [<c08d6948>] (warn_slowpath_fmt+0xa0/0xe4) [ 1946.506758] r7:00000009 r6:0000001c r5:c0a71dc8 r4:c0a71e04 [ 1946.517070] [<c08d68ac>] (warn_slowpath_fmt) from [<c04a948c>] (refcount_warn_saturate+0x110/0x15c) [ 1946.535309] r8:c0100224 r7:c0dfcb84 r6:ffffffff r5:c3b84c00 r4:c24a17c0 [ 1946.546708] [<c04a937c>] (refcount_warn_saturate) from [<c0380134>] (eventfd_ctx_put+0x48/0x74) [ 1946.564476] [<c03800ec>] (eventfd_ctx_put) from [<bf5464e8>] (ffs_data_clear+0xd0/0x118 [usb_f_fs]) [ 1946.582664] r5:c3b84c00 r4:c2695b00 [ 1946.590668] [<bf546418>] (ffs_data_clear [usb_f_fs]) from [<bf547cc0>] (ffs_data_closed+0x9c/0x150 [usb_f_fs]) [ 1946.609608] r5:bf54d014 r4:c2695b00 [ 1946.617522] [<bf547c24>] (ffs_data_closed [usb_f_fs]) from [<bf547da0>] (ffs_fs_kill_sb+0x2c/0x30 [usb_f_fs]) [ 1946.636217] r7:c0dfcb ---truncated---

In the Linux kernel, the following vulnerability has been resolved: usb: mtu3: fix list_head check warning This is caused by uninitialization of list_head. BUG: KASAN: use-after-free in __list_del_entry_valid+0x34/0xe4 Call trace: dump_backtrace+0x0/0x298 show_stack+0x24/0x34 dump_stack+0x130/0x1a8 print_address_description+0x88/0x56c __kasan_report+0x1b8/0x2a0 kasan_report+0x14/0x20 __asan_load8+0x9c/0xa0 __list_del_entry_valid+0x34/0xe4 mtu3_req_complete+0x4c/0x300 [mtu3] mtu3_gadget_stop+0x168/0x448 [mtu3] usb_gadget_unregister_driver+0x204/0x3a0 unregister_gadget_item+0x44/0xa4

In the Linux kernel, the following vulnerability has been resolved: btrfs: abort in rename_exchange if we fail to insert the second ref Error injection stress uncovered a problem where we'd leave a dangling inode ref if we failed during a rename_exchange. This happens because we insert the inode ref for one side of the rename, and then for the other side. If this second inode ref insert fails we'll leave the first one dangling and leave a corrupt file system behind. Fix this by aborting if we did the insert for the first inode ref.

In the Linux kernel, the following vulnerability has been resolved: usb: dwc3: gadget: Free gadget structure only after freeing endpoints As part of commit e81a7018d93a ("usb: dwc3: allocate gadget structure dynamically") the dwc3_gadget_release() was added which will free the dwc->gadget structure upon the device's removal when usb_del_gadget_udc() is called in dwc3_gadget_exit(). However, simply freeing the gadget results a dangling pointer situation: the endpoints created in dwc3_gadget_init_endpoints() have their dep->endpoint.ep_list members chained off the list_head anchored at dwc->gadget->ep_list. Thus when dwc->gadget is freed, the first dwc3_ep in the list now has a dangling prev pointer and likewise for the next pointer of the dwc3_ep at the tail of the list. The dwc3_gadget_free_endpoints() that follows will result in a use-after-free when it calls list_del(). This was caught by enabling KASAN and performing a driver unbind. The recent commit 568262bf5492 ("usb: dwc3: core: Add shutdown callback for dwc3") also exposes this as a panic during shutdown. There are a few possibilities to fix this. One could be to perform a list_del() of the gadget->ep_list itself which removes it from the rest of the dwc3_ep chain. Another approach is what this patch does, by splitting up the usb_del_gadget_udc() call into its separate "del" and "put" components. This allows dwc3_gadget_free_endpoints() to be called before the gadget is finally freed with usb_put_gadget().

In the Linux kernel, the following vulnerability has been resolved: spi: fix use-after-free of the add_lock mutex Commit 6098475d4cb4 ("spi: Fix deadlock when adding SPI controllers on SPI buses") introduced a per-controller mutex. But mutex_unlock() of said lock is called after the controller is already freed: spi_unregister_controller(ctlr) -> put_device(&ctlr->dev) -> spi_controller_release(dev) -> mutex_unlock(&ctrl->add_lock) Move the put_device() after the mutex_unlock().

In the Linux kernel, the following vulnerability has been resolved: RDMA/irdma: Fix KASAN issue with tasklet KASAN testing revealed the following issue assocated with freeing an IRQ. [50006.466686] Call Trace: [50006.466691] <IRQ> [50006.489538] dump_stack+0x5c/0x80 [50006.493475] print_address_description.constprop.6+0x1a/0x150 [50006.499872] ? irdma_sc_process_ceq+0x483/0x790 [irdma] [50006.505742] ? irdma_sc_process_ceq+0x483/0x790 [irdma] [50006.511644] kasan_report.cold.11+0x7f/0x118 [50006.516572] ? irdma_sc_process_ceq+0x483/0x790 [irdma] [50006.522473] irdma_sc_process_ceq+0x483/0x790 [irdma] [50006.528232] irdma_process_ceq+0xb2/0x400 [irdma] [50006.533601] ? irdma_hw_flush_wqes_callback+0x370/0x370 [irdma] [50006.540298] irdma_ceq_dpc+0x44/0x100 [irdma] [50006.545306] tasklet_action_common.isra.14+0x148/0x2c0 [50006.551096] __do_softirq+0x1d0/0xaf8 [50006.555396] irq_exit_rcu+0x219/0x260 [50006.559670] irq_exit+0xa/0x20 [50006.563320] smp_apic_timer_interrupt+0x1bf/0x690 [50006.568645] apic_timer_interrupt+0xf/0x20 [50006.573341] </IRQ> The issue is that a tasklet could be pending on another core racing the delete of the irq. Fix by insuring any scheduled tasklet is killed after deleting the irq.

In the Linux kernel, the following vulnerability has been resolved: net: atlantic: Fix DMA mapping for PTP hwts ring Function aq_ring_hwts_rx_alloc() maps extra AQ_CFG_RXDS_DEF bytes for PTP HWTS ring but then generic aq_ring_free() does not take this into account. Create and use a specific function to free HWTS ring to fix this issue. Trace: [ 215.351607] ------------[ cut here ]------------ [ 215.351612] DMA-API: atlantic 0000:4b:00.0: device driver frees DMA memory with different size [device address=0x00000000fbdd0000] [map size=34816 bytes] [unmap size=32768 bytes] [ 215.351635] WARNING: CPU: 33 PID: 10759 at kernel/dma/debug.c:988 check_unmap+0xa6f/0x2360 ... [ 215.581176] Call Trace: [ 215.583632] <TASK> [ 215.585745] ? show_trace_log_lvl+0x1c4/0x2df [ 215.590114] ? show_trace_log_lvl+0x1c4/0x2df [ 215.594497] ? debug_dma_free_coherent+0x196/0x210 [ 215.599305] ? check_unmap+0xa6f/0x2360 [ 215.603147] ? __warn+0xca/0x1d0 [ 215.606391] ? check_unmap+0xa6f/0x2360 [ 215.610237] ? report_bug+0x1ef/0x370 [ 215.613921] ? handle_bug+0x3c/0x70 [ 215.617423] ? exc_invalid_op+0x14/0x50 [ 215.621269] ? asm_exc_invalid_op+0x16/0x20 [ 215.625480] ? check_unmap+0xa6f/0x2360 [ 215.629331] ? mark_lock.part.0+0xca/0xa40 [ 215.633445] debug_dma_free_coherent+0x196/0x210 [ 215.638079] ? __pfx_debug_dma_free_coherent+0x10/0x10 [ 215.643242] ? slab_free_freelist_hook+0x11d/0x1d0 [ 215.648060] dma_free_attrs+0x6d/0x130 [ 215.651834] aq_ring_free+0x193/0x290 [atlantic] [ 215.656487] aq_ptp_ring_free+0x67/0x110 [atlantic] ... [ 216.127540] ---[ end trace 6467e5964dd2640b ]--- [ 216.132160] DMA-API: Mapped at: [ 216.132162] debug_dma_alloc_coherent+0x66/0x2f0 [ 216.132165] dma_alloc_attrs+0xf5/0x1b0 [ 216.132168] aq_ring_hwts_rx_alloc+0x150/0x1f0 [atlantic] [ 216.132193] aq_ptp_ring_alloc+0x1bb/0x540 [atlantic] [ 216.132213] aq_nic_init+0x4a1/0x760 [atlantic]

In the Linux kernel, the following vulnerability has been resolved: drm/amdgpu: fix use-after-free bug The bug can be triggered by sending a single amdgpu_gem_userptr_ioctl to the AMDGPU DRM driver on any ASICs with an invalid address and size. The bug was reported by Joonkyo Jung <joonkyoj@yonsei.ac.kr>. For example the following code: static void Syzkaller1(int fd) { struct drm_amdgpu_gem_userptr arg; int ret; arg.addr = 0xffffffffffff0000; arg.size = 0x80000000; /*2 Gb*/ arg.flags = 0x7; ret = drmIoctl(fd, 0xc1186451/*amdgpu_gem_userptr_ioctl*/, &arg); } Due to the address and size are not valid there is a failure in amdgpu_hmm_register->mmu_interval_notifier_insert->__mmu_interval_notifier_insert-> check_shl_overflow, but we even the amdgpu_hmm_register failure we still call amdgpu_hmm_unregister into amdgpu_gem_object_free which causes access to a bad address. The following stack is below when the issue is reproduced when Kazan is enabled: [ +0.000014] Hardware name: ASUS System Product Name/ROG STRIX B550-F GAMING (WI-FI), BIOS 1401 12/03/2020 [ +0.000009] RIP: 0010:mmu_interval_notifier_remove+0x327/0x340 [ +0.000017] Code: ff ff 49 89 44 24 08 48 b8 00 01 00 00 00 00 ad de 4c 89 f7 49 89 47 40 48 83 c0 22 49 89 47 48 e8 ce d1 2d 01 e9 32 ff ff ff <0f> 0b e9 16 ff ff ff 4c 89 ef e8 fa 14 b3 ff e9 36 ff ff ff e8 80 [ +0.000014] RSP: 0018:ffffc90002657988 EFLAGS: 00010246 [ +0.000013] RAX: 0000000000000000 RBX: 1ffff920004caf35 RCX: ffffffff8160565b [ +0.000011] RDX: dffffc0000000000 RSI: 0000000000000004 RDI: ffff8881a9f78260 [ +0.000010] RBP: ffffc90002657a70 R08: 0000000000000001 R09: fffff520004caf25 [ +0.000010] R10: 0000000000000003 R11: ffffffff8161d1d6 R12: ffff88810e988c00 [ +0.000010] R13: ffff888126fb5a00 R14: ffff88810e988c0c R15: ffff8881a9f78260 [ +0.000011] FS: 00007ff9ec848540(0000) GS:ffff8883cc880000(0000) knlGS:0000000000000000 [ +0.000012] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ +0.000010] CR2: 000055b3f7e14328 CR3: 00000001b5770000 CR4: 0000000000350ef0 [ +0.000010] Call Trace: [ +0.000006] <TASK> [ +0.000007] ? show_regs+0x6a/0x80 [ +0.000018] ? __warn+0xa5/0x1b0 [ +0.000019] ? mmu_interval_notifier_remove+0x327/0x340 [ +0.000018] ? report_bug+0x24a/0x290 [ +0.000022] ? handle_bug+0x46/0x90 [ +0.000015] ? exc_invalid_op+0x19/0x50 [ +0.000016] ? asm_exc_invalid_op+0x1b/0x20 [ +0.000017] ? kasan_save_stack+0x26/0x50 [ +0.000017] ? mmu_interval_notifier_remove+0x23b/0x340 [ +0.000019] ? mmu_interval_notifier_remove+0x327/0x340 [ +0.000019] ? mmu_interval_notifier_remove+0x23b/0x340 [ +0.000020] ? __pfx_mmu_interval_notifier_remove+0x10/0x10 [ +0.000017] ? kasan_save_alloc_info+0x1e/0x30 [ +0.000018] ? srso_return_thunk+0x5/0x5f [ +0.000014] ? __kasan_kmalloc+0xb1/0xc0 [ +0.000018] ? srso_return_thunk+0x5/0x5f [ +0.000013] ? __kasan_check_read+0x11/0x20 [ +0.000020] amdgpu_hmm_unregister+0x34/0x50 [amdgpu] [ +0.004695] amdgpu_gem_object_free+0x66/0xa0 [amdgpu] [ +0.004534] ? __pfx_amdgpu_gem_object_free+0x10/0x10 [amdgpu] [ +0.004291] ? do_syscall_64+0x5f/0xe0 [ +0.000023] ? srso_return_thunk+0x5/0x5f [ +0.000017] drm_gem_object_free+0x3b/0x50 [drm] [ +0.000489] amdgpu_gem_userptr_ioctl+0x306/0x500 [amdgpu] [ +0.004295] ? __pfx_amdgpu_gem_userptr_ioctl+0x10/0x10 [amdgpu] [ +0.004270] ? srso_return_thunk+0x5/0x5f [ +0.000014] ? __this_cpu_preempt_check+0x13/0x20 [ +0.000015] ? srso_return_thunk+0x5/0x5f [ +0.000013] ? sysvec_apic_timer_interrupt+0x57/0xc0 [ +0.000020] ? srso_return_thunk+0x5/0x5f [ +0.000014] ? asm_sysvec_apic_timer_interrupt+0x1b/0x20 [ +0.000022] ? drm_ioctl_kernel+0x17b/0x1f0 [drm] [ +0.000496] ? __pfx_amdgpu_gem_userptr_ioctl+0x10/0x10 [amdgpu] [ +0.004272] ? drm_ioctl_kernel+0x190/0x1f0 [drm] [ +0.000492] drm_ioctl_kernel+0x140/0x1f0 [drm] [ +0.000497] ? __pfx_amdgpu_gem_userptr_ioctl+0x10/0x10 [amdgpu] [ +0.004297] ? __pfx_drm_ioctl_kernel+0x10/0x10 [d ---truncated---

In the Linux kernel, the following vulnerability has been resolved: ipv6: sr: fix possible use-after-free and null-ptr-deref The pernet operations structure for the subsystem must be registered before registering the generic netlink family.

In the Linux kernel, the following vulnerability has been resolved: spi: lpspi: Avoid potential use-after-free in probe() fsl_lpspi_probe() is allocating/disposing memory manually with spi_alloc_host()/spi_alloc_target(), but uses devm_spi_register_controller(). In case of error after the latter call the memory will be explicitly freed in the probe function by spi_controller_put() call, but used afterwards by "devm" management outside probe() (spi_unregister_controller() <- devm_spi_unregister() below). Unable to handle kernel NULL pointer dereference at virtual address 0000000000000070 ... Call trace: kernfs_find_ns kernfs_find_and_get_ns sysfs_remove_group sysfs_remove_groups device_remove_attrs device_del spi_unregister_controller devm_spi_unregister release_nodes devres_release_all really_probe driver_probe_device __device_attach_driver bus_for_each_drv __device_attach device_initial_probe bus_probe_device deferred_probe_work_func process_one_work worker_thread kthread ret_from_fork

A use-after-free flaw was found in the add_partition in block/partitions/core.c in the Linux kernel. A local attacker with user privileges could cause a denial of service on the system. The issue results from the lack of code cleanup when device_add call fails when adding a partition to the disk.

A vulnerability was found in the Linux kernel, where accessing a deallocated instance in printer_ioctl() printer_ioctl() tries to access of a printer_dev instance. However, use-after-free arises because it had been freed by gprinter_free().

A use-after-free flaw was found in lan78xx_disconnect in drivers/net/usb/lan78xx.c in the network sub-component, net/usb/lan78xx in the Linux Kernel. This flaw allows a local attacker to crash the system when the LAN78XX USB device detaches.

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: Fix possible deadlock in rfcomm_sk_state_change syzbot reports a possible deadlock in rfcomm_sk_state_change [1]. While rfcomm_sock_connect acquires the sk lock and waits for the rfcomm lock, rfcomm_sock_release could have the rfcomm lock and hit a deadlock for acquiring the sk lock. Here's a simplified flow: rfcomm_sock_connect: lock_sock(sk) rfcomm_dlc_open: rfcomm_lock() rfcomm_sock_release: rfcomm_sock_shutdown: rfcomm_lock() __rfcomm_dlc_close: rfcomm_k_state_change: lock_sock(sk) This patch drops the sk lock before calling rfcomm_dlc_open to avoid the possible deadlock and holds sk's reference count to prevent use-after-free after rfcomm_dlc_open completes.

In the Linux kernel, the following vulnerability has been resolved: drm/i915: Fix potential context UAFs gem_context_register() makes the context visible to userspace, and which point a separate thread can trigger the I915_GEM_CONTEXT_DESTROY ioctl. So we need to ensure that nothing uses the ctx ptr after this. And we need to ensure that adding the ctx to the xarray is the *last* thing that gem_context_register() does with the ctx pointer. [tursulin: Stable and fixes tags add/tidy.] (cherry picked from commit bed4b455cf5374e68879be56971c1da563bcd90c)

In the Linux kernel, the following vulnerability has been resolved: nfc: pn533: Wait for out_urb's completion in pn533_usb_send_frame() Fix a use-after-free that occurs in hcd when in_urb sent from pn533_usb_send_frame() is completed earlier than out_urb. Its callback frees the skb data in pn533_send_async_complete() that is used as a transfer buffer of out_urb. Wait before sending in_urb until the callback of out_urb is called. To modify the callback of out_urb alone, separate the complete function of out_urb and ack_urb. Found by a modified version of syzkaller. BUG: KASAN: use-after-free in dummy_timer Call Trace: memcpy (mm/kasan/shadow.c:65) dummy_perform_transfer (drivers/usb/gadget/udc/dummy_hcd.c:1352) transfer (drivers/usb/gadget/udc/dummy_hcd.c:1453) dummy_timer (drivers/usb/gadget/udc/dummy_hcd.c:1972) arch_static_branch (arch/x86/include/asm/jump_label.h:27) static_key_false (include/linux/jump_label.h:207) timer_expire_exit (include/trace/events/timer.h:127) call_timer_fn (kernel/time/timer.c:1475) expire_timers (kernel/time/timer.c:1519) __run_timers (kernel/time/timer.c:1790) run_timer_softirq (kernel/time/timer.c:1803)

In the Linux kernel, the following vulnerability has been resolved: x86/mm, kexec, ima: Use memblock_free_late() from ima_free_kexec_buffer() The code calling ima_free_kexec_buffer() runs long after the memblock allocator has already been torn down, potentially resulting in a use after free in memblock_isolate_range(). With KASAN or KFENCE, this use after free will result in a BUG from the idle task, and a subsequent kernel panic. Switch ima_free_kexec_buffer() over to memblock_free_late() to avoid that bug.

The __do_follow_link function in fs/namei.c in the Linux kernel before 2.6.33 does not properly handle the last pathname component during use of certain filesystems, which allows local users to cause a denial of service (incorrect free operations and system crash) via an open system call.

In the Linux kernel, the following vulnerability has been resolved: smb: client: fix potential UAF in smb2_is_valid_oplock_break() Skip sessions that are being teared down (status == SES_EXITING) to avoid UAF.

A use-after-free vulnerability was found in the siano smsusb module in the Linux kernel. The bug occurs during device initialization when the siano device is plugged in. This flaw allows a local user to crash the system, causing a denial of service condition.

A use-after-free vulnerability was found in the cyttsp4_core driver in the Linux kernel. This issue occurs in the device cleanup routine due to a possible rearming of the watchdog_timer from the workqueue. This could allow a local user to crash the system, causing a denial of service.

A use-after-free vulnerability was found in the cxgb4 driver in the Linux kernel. The bug occurs when the cxgb4 device is detaching due to a possible rearming of the flower_stats_timer from the work queue. This flaw allows a local user to crash the system, causing a denial of service condition.

A use after free flaw was found in hfsplus_put_super in fs/hfsplus/super.c in the Linux Kernel. This flaw could allow a local user to cause a denial of service problem.

In the Linux kernel, the following vulnerability has been resolved: soc: qcom: pmic_glink_altmode: fix drm bridge use-after-free A recent DRM series purporting to simplify support for "transparent bridges" and handling of probe deferrals ironically exposed a use-after-free issue on pmic_glink_altmode probe deferral. This has manifested itself as the display subsystem occasionally failing to initialise and NULL-pointer dereferences during boot of machines like the Lenovo ThinkPad X13s. Specifically, the dp-hpd bridge is currently registered before all resources have been acquired which means that it can also be deregistered on probe deferrals. In the meantime there is a race window where the new aux bridge driver (or PHY driver previously) may have looked up the dp-hpd bridge and stored a (non-reference-counted) pointer to the bridge which is about to be deallocated. When the display controller is later initialised, this triggers a use-after-free when attaching the bridges: dp -> aux -> dp-hpd (freed) which may, for example, result in the freed bridge failing to attach: [drm:drm_bridge_attach [drm]] *ERROR* failed to attach bridge /soc@0/phy@88eb000 to encoder TMDS-31: -16 or a NULL-pointer dereference: Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000 ... Call trace: drm_bridge_attach+0x70/0x1a8 [drm] drm_aux_bridge_attach+0x24/0x38 [aux_bridge] drm_bridge_attach+0x80/0x1a8 [drm] dp_bridge_init+0xa8/0x15c [msm] msm_dp_modeset_init+0x28/0xc4 [msm] The DRM bridge implementation is clearly fragile and implicitly built on the assumption that bridges may never go away. In this case, the fix is to move the bridge registration in the pmic_glink_altmode driver to after all resources have been looked up. Incidentally, with the new dp-hpd bridge implementation, which registers child devices, this is also a requirement due to a long-standing issue in driver core that can otherwise lead to a probe deferral loop (see commit fbc35b45f9f6 ("Add documentation on meaning of -EPROBE_DEFER")). [DB: slightly fixed commit message by adding the word 'commit']

A use-after-free flaw was found in the Linux kernel’s core dump subsystem. This flaw allows a local user to crash the system. Only if patch 390031c94211 ("coredump: Use the vma snapshot in fill_files_note") not applied yet, then kernel could be affected.

A use-after-free flaw was found in io_uring/filetable.c in io_install_fixed_file in the io_uring subcomponent in the Linux Kernel during call cleanup. This flaw may lead to a denial of service.

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: Avoid potential use-after-free in hci_error_reset While handling the HCI_EV_HARDWARE_ERROR event, if the underlying BT controller is not responding, the GPIO reset mechanism would free the hci_dev and lead to a use-after-free in hci_error_reset. Here's the call trace observed on a ChromeOS device with Intel AX201: queue_work_on+0x3e/0x6c __hci_cmd_sync_sk+0x2ee/0x4c0 [bluetooth <HASH:3b4a6>] ? init_wait_entry+0x31/0x31 __hci_cmd_sync+0x16/0x20 [bluetooth <HASH:3b4a 6>] hci_error_reset+0x4f/0xa4 [bluetooth <HASH:3b4a 6>] process_one_work+0x1d8/0x33f worker_thread+0x21b/0x373 kthread+0x13a/0x152 ? pr_cont_work+0x54/0x54 ? kthread_blkcg+0x31/0x31 ret_from_fork+0x1f/0x30 This patch holds the reference count on the hci_dev while processing a HCI_EV_HARDWARE_ERROR event to avoid potential crash.

A use-after-free flaw was found in reconn_set_ipaddr_from_hostname in fs/cifs/connect.c in the Linux kernel. The issue occurs when it forgets to set the free pointer server->hostname to NULL, leading to an invalid pointer request.

In the Linux kernel, the following vulnerability has been resolved: NFC: port100: fix use-after-free in port100_send_complete Syzbot reported UAF in port100_send_complete(). The root case is in missing usb_kill_urb() calls on error handling path of ->probe function. port100_send_complete() accesses devm allocated memory which will be freed on probe failure. We should kill this urbs before returning an error from probe function to prevent reported use-after-free Fail log: BUG: KASAN: use-after-free in port100_send_complete+0x16e/0x1a0 drivers/nfc/port100.c:935 Read of size 1 at addr ffff88801bb59540 by task ksoftirqd/2/26 ... Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 print_address_description.constprop.0.cold+0x8d/0x303 mm/kasan/report.c:255 __kasan_report mm/kasan/report.c:442 [inline] kasan_report.cold+0x83/0xdf mm/kasan/report.c:459 port100_send_complete+0x16e/0x1a0 drivers/nfc/port100.c:935 __usb_hcd_giveback_urb+0x2b0/0x5c0 drivers/usb/core/hcd.c:1670 ... Allocated by task 1255: kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38 kasan_set_track mm/kasan/common.c:45 [inline] set_alloc_info mm/kasan/common.c:436 [inline] ____kasan_kmalloc mm/kasan/common.c:515 [inline] ____kasan_kmalloc mm/kasan/common.c:474 [inline] __kasan_kmalloc+0xa6/0xd0 mm/kasan/common.c:524 alloc_dr drivers/base/devres.c:116 [inline] devm_kmalloc+0x96/0x1d0 drivers/base/devres.c:823 devm_kzalloc include/linux/device.h:209 [inline] port100_probe+0x8a/0x1320 drivers/nfc/port100.c:1502 Freed by task 1255: kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38 kasan_set_track+0x21/0x30 mm/kasan/common.c:45 kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:370 ____kasan_slab_free mm/kasan/common.c:366 [inline] ____kasan_slab_free+0xff/0x140 mm/kasan/common.c:328 kasan_slab_free include/linux/kasan.h:236 [inline] __cache_free mm/slab.c:3437 [inline] kfree+0xf8/0x2b0 mm/slab.c:3794 release_nodes+0x112/0x1a0 drivers/base/devres.c:501 devres_release_all+0x114/0x190 drivers/base/devres.c:530 really_probe+0x626/0xcc0 drivers/base/dd.c:670

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_core: Fix leaking sent_cmd skb sent_cmd memory is not freed before freeing hci_dev causing it to leak it contents.