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.

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.

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.

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.

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.

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---

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: 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: phy: ti: tusb1210: Resolve charger-det crash if charger psy is unregistered The power_supply frame-work is not really designed for there to be long living in kernel references to power_supply devices. Specifically unregistering a power_supply while some other code has a reference to it triggers a WARN in power_supply_unregister(): WARN_ON(atomic_dec_return(&psy->use_cnt)); Folllowed by the power_supply still getting removed and the backing data freed anyway, leaving the tusb1210 charger-detect code with a dangling reference, resulting in a crash the next time tusb1210_get_online() is called. Fix this by only holding the reference in tusb1210_get_online() freeing it at the end of the function. Note this still leaves a theoretical race window, but it avoids the issue when manually rmmod-ing the charger chip driver during development.

In the Linux kernel, the following vulnerability has been resolved: bpf: Fix too early release of tcx_entry Pedro Pinto and later independently also Hyunwoo Kim and Wongi Lee reported an issue that the tcx_entry can be released too early leading to a use after free (UAF) when an active old-style ingress or clsact qdisc with a shared tc block is later replaced by another ingress or clsact instance. Essentially, the sequence to trigger the UAF (one example) can be as follows: 1. A network namespace is created 2. An ingress qdisc is created. This allocates a tcx_entry, and &tcx_entry->miniq is stored in the qdisc's miniqp->p_miniq. At the same time, a tcf block with index 1 is created. 3. chain0 is attached to the tcf block. chain0 must be connected to the block linked to the ingress qdisc to later reach the function tcf_chain0_head_change_cb_del() which triggers the UAF. 4. Create and graft a clsact qdisc. This causes the ingress qdisc created in step 1 to be removed, thus freeing the previously linked tcx_entry: rtnetlink_rcv_msg() => tc_modify_qdisc() => qdisc_create() => clsact_init() [a] => qdisc_graft() => qdisc_destroy() => __qdisc_destroy() => ingress_destroy() [b] => tcx_entry_free() => kfree_rcu() // tcx_entry freed 5. Finally, the network namespace is closed. This registers the cleanup_net worker, and during the process of releasing the remaining clsact qdisc, it accesses the tcx_entry that was already freed in step 4, causing the UAF to occur: cleanup_net() => ops_exit_list() => default_device_exit_batch() => unregister_netdevice_many() => unregister_netdevice_many_notify() => dev_shutdown() => qdisc_put() => clsact_destroy() [c] => tcf_block_put_ext() => tcf_chain0_head_change_cb_del() => tcf_chain_head_change_item() => clsact_chain_head_change() => mini_qdisc_pair_swap() // UAF There are also other variants, the gist is to add an ingress (or clsact) qdisc with a specific shared block, then to replace that qdisc, waiting for the tcx_entry kfree_rcu() to be executed and subsequently accessing the current active qdisc's miniq one way or another. The correct fix is to turn the miniq_active boolean into a counter. What can be observed, at step 2 above, the counter transitions from 0->1, at step [a] from 1->2 (in order for the miniq object to remain active during the replacement), then in [b] from 2->1 and finally [c] 1->0 with the eventual release. The reference counter in general ranges from [0,2] and it does not need to be atomic since all access to the counter is protected by the rtnl mutex. With this in place, there is no longer a UAF happening and the tcx_entry is freed at the correct time.

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.

In the Linux kernel, the following vulnerability has been resolved: scsi: qla2xxx: Fix use after free on unload System crash is observed with stack trace warning of use after free. There are 2 signals to tell dpc_thread to terminate (UNLOADING flag and kthread_stop). On setting the UNLOADING flag when dpc_thread happens to run at the time and sees the flag, this causes dpc_thread to exit and clean up itself. When kthread_stop is called for final cleanup, this causes use after free. Remove UNLOADING signal to terminate dpc_thread. Use the kthread_stop as the main signal to exit dpc_thread. [596663.812935] kernel BUG at mm/slub.c:294! [596663.812950] invalid opcode: 0000 [#1] SMP PTI [596663.812957] CPU: 13 PID: 1475935 Comm: rmmod Kdump: loaded Tainted: G IOE --------- - - 4.18.0-240.el8.x86_64 #1 [596663.812960] Hardware name: HP ProLiant DL380p Gen8, BIOS P70 08/20/2012 [596663.812974] RIP: 0010:__slab_free+0x17d/0x360 ... [596663.813008] Call Trace: [596663.813022] ? __dentry_kill+0x121/0x170 [596663.813030] ? _cond_resched+0x15/0x30 [596663.813034] ? _cond_resched+0x15/0x30 [596663.813039] ? wait_for_completion+0x35/0x190 [596663.813048] ? try_to_wake_up+0x63/0x540 [596663.813055] free_task+0x5a/0x60 [596663.813061] kthread_stop+0xf3/0x100 [596663.813103] qla2x00_remove_one+0x284/0x440 [qla2xxx]

In the Linux kernel, the following vulnerability has been resolved: fbdev: efifb: Register sysfs groups through driver core The driver core can register and cleanup sysfs groups already. Make use of that functionality to simplify the error handling and cleanup. Also avoid a UAF race during unregistering where the sysctl attributes were usable after the info struct was freed.

In the Linux kernel, the following vulnerability has been resolved: net: microchip: vcap api: Fix memory leaks in vcap_api_encode_rule_test() Commit a3c1e45156ad ("net: microchip: vcap: Fix use-after-free error in kunit test") fixed the use-after-free error, but introduced below memory leaks by removing necessary vcap_free_rule(), add it to fix it. unreferenced object 0xffffff80ca58b700 (size 192): comm "kunit_try_catch", pid 1215, jiffies 4294898264 hex dump (first 32 bytes): 00 12 7a 00 05 00 00 00 0a 00 00 00 64 00 00 00 ..z.........d... 00 00 00 00 00 00 00 00 00 04 0b cc 80 ff ff ff ................ backtrace (crc 9c09c3fe): [<0000000052a0be73>] kmemleak_alloc+0x34/0x40 [<0000000043605459>] __kmalloc_cache_noprof+0x26c/0x2f4 [<0000000040a01b8d>] vcap_alloc_rule+0x3cc/0x9c4 [<000000003fe86110>] vcap_api_encode_rule_test+0x1ac/0x16b0 [<00000000b3595fc4>] kunit_try_run_case+0x13c/0x3ac [<0000000010f5d2bf>] kunit_generic_run_threadfn_adapter+0x80/0xec [<00000000c5d82c9a>] kthread+0x2e8/0x374 [<00000000f4287308>] ret_from_fork+0x10/0x20 unreferenced object 0xffffff80cc0b0400 (size 64): comm "kunit_try_catch", pid 1215, jiffies 4294898265 hex dump (first 32 bytes): 80 04 0b cc 80 ff ff ff 18 b7 58 ca 80 ff ff ff ..........X..... 39 00 00 00 02 00 00 00 06 05 04 03 02 01 ff ff 9............... backtrace (crc daf014e9): [<0000000052a0be73>] kmemleak_alloc+0x34/0x40 [<0000000043605459>] __kmalloc_cache_noprof+0x26c/0x2f4 [<000000000ff63fd4>] vcap_rule_add_key+0x2cc/0x528 [<00000000dfdb1e81>] vcap_api_encode_rule_test+0x224/0x16b0 [<00000000b3595fc4>] kunit_try_run_case+0x13c/0x3ac [<0000000010f5d2bf>] kunit_generic_run_threadfn_adapter+0x80/0xec [<00000000c5d82c9a>] kthread+0x2e8/0x374 [<00000000f4287308>] ret_from_fork+0x10/0x20 unreferenced object 0xffffff80cc0b0700 (size 64): comm "kunit_try_catch", pid 1215, jiffies 4294898265 hex dump (first 32 bytes): 80 07 0b cc 80 ff ff ff 28 b7 58 ca 80 ff ff ff ........(.X..... 3c 00 00 00 00 00 00 00 01 2f 03 b3 ec ff ff ff <......../...... backtrace (crc 8d877792): [<0000000052a0be73>] kmemleak_alloc+0x34/0x40 [<0000000043605459>] __kmalloc_cache_noprof+0x26c/0x2f4 [<000000006eadfab7>] vcap_rule_add_action+0x2d0/0x52c [<00000000323475d1>] vcap_api_encode_rule_test+0x4d4/0x16b0 [<00000000b3595fc4>] kunit_try_run_case+0x13c/0x3ac [<0000000010f5d2bf>] kunit_generic_run_threadfn_adapter+0x80/0xec [<00000000c5d82c9a>] kthread+0x2e8/0x374 [<00000000f4287308>] ret_from_fork+0x10/0x20 unreferenced object 0xffffff80cc0b0900 (size 64): comm "kunit_try_catch", pid 1215, jiffies 4294898266 hex dump (first 32 bytes): 80 09 0b cc 80 ff ff ff 80 06 0b cc 80 ff ff ff ................ 7d 00 00 00 01 00 00 00 00 00 00 00 ff 00 00 00 }............... backtrace (crc 34181e56): [<0000000052a0be73>] kmemleak_alloc+0x34/0x40 [<0000000043605459>] __kmalloc_cache_noprof+0x26c/0x2f4 [<000000000ff63fd4>] vcap_rule_add_key+0x2cc/0x528 [<00000000991e3564>] vcap_val_rule+0xcf0/0x13e8 [<00000000fc9868e5>] vcap_api_encode_rule_test+0x678/0x16b0 [<00000000b3595fc4>] kunit_try_run_case+0x13c/0x3ac [<0000000010f5d2bf>] kunit_generic_run_threadfn_adapter+0x80/0xec [<00000000c5d82c9a>] kthread+0x2e8/0x374 [<00000000f4287308>] ret_from_fork+0x10/0x20 unreferenced object 0xffffff80cc0b0980 (size 64): comm "kunit_try_catch", pid 1215, jiffies 4294898266 hex dump (first 32 bytes): 18 b7 58 ca 80 ff ff ff 00 09 0b cc 80 ff ff ff ..X............. 67 00 00 00 00 00 00 00 01 01 74 88 c0 ff ff ff g.........t..... backtrace (crc 275fd9be): [<0000000052a0be73>] kmemleak_alloc+0x34/0x40 [<0000000043605459>] __kmalloc_cache_noprof+0x26c/0x2f4 [<000000000ff63fd4>] vcap_rule_add_key+0x2cc/0x528 [<000000001396a1a2>] test_add_de ---truncated---

In the Linux kernel, the following vulnerability has been resolved: thermal: core: Free tzp copy along with the thermal zone The object pointed to by tz->tzp may still be accessed after being freed in thermal_zone_device_unregister(), so move the freeing of it to the point after the removal completion has been completed at which it cannot be accessed any more.

In the Linux kernel, the following vulnerability has been resolved: btrfs: wait for fixup workers before stopping cleaner kthread during umount During unmount, at close_ctree(), we have the following steps in this order: 1) Park the cleaner kthread - this doesn't destroy the kthread, it basically halts its execution (wake ups against it work but do nothing); 2) We stop the cleaner kthread - this results in freeing the respective struct task_struct; 3) We call btrfs_stop_all_workers() which waits for any jobs running in all the work queues and then free the work queues. Syzbot reported a case where a fixup worker resulted in a crash when doing a delayed iput on its inode while attempting to wake up the cleaner at btrfs_add_delayed_iput(), because the task_struct of the cleaner kthread was already freed. This can happen during unmount because we don't wait for any fixup workers still running before we call kthread_stop() against the cleaner kthread, which stops and free all its resources. Fix this by waiting for any fixup workers at close_ctree() before we call kthread_stop() against the cleaner and run pending delayed iputs. The stack traces reported by syzbot were the following: BUG: KASAN: slab-use-after-free in __lock_acquire+0x77/0x2050 kernel/locking/lockdep.c:5065 Read of size 8 at addr ffff8880272a8a18 by task kworker/u8:3/52 CPU: 1 UID: 0 PID: 52 Comm: kworker/u8:3 Not tainted 6.12.0-rc1-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 Workqueue: btrfs-fixup btrfs_work_helper Call Trace: <TASK> __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:377 [inline] print_report+0x169/0x550 mm/kasan/report.c:488 kasan_report+0x143/0x180 mm/kasan/report.c:601 __lock_acquire+0x77/0x2050 kernel/locking/lockdep.c:5065 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5825 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xd5/0x120 kernel/locking/spinlock.c:162 class_raw_spinlock_irqsave_constructor include/linux/spinlock.h:551 [inline] try_to_wake_up+0xb0/0x1480 kernel/sched/core.c:4154 btrfs_writepage_fixup_worker+0xc16/0xdf0 fs/btrfs/inode.c:2842 btrfs_work_helper+0x390/0xc50 fs/btrfs/async-thread.c:314 process_one_work kernel/workqueue.c:3229 [inline] process_scheduled_works+0xa63/0x1850 kernel/workqueue.c:3310 worker_thread+0x870/0xd30 kernel/workqueue.c:3391 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 </TASK> Allocated by task 2: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3f/0x80 mm/kasan/common.c:68 unpoison_slab_object mm/kasan/common.c:319 [inline] __kasan_slab_alloc+0x66/0x80 mm/kasan/common.c:345 kasan_slab_alloc include/linux/kasan.h:247 [inline] slab_post_alloc_hook mm/slub.c:4086 [inline] slab_alloc_node mm/slub.c:4135 [inline] kmem_cache_alloc_node_noprof+0x16b/0x320 mm/slub.c:4187 alloc_task_struct_node kernel/fork.c:180 [inline] dup_task_struct+0x57/0x8c0 kernel/fork.c:1107 copy_process+0x5d1/0x3d50 kernel/fork.c:2206 kernel_clone+0x223/0x880 kernel/fork.c:2787 kernel_thread+0x1bc/0x240 kernel/fork.c:2849 create_kthread kernel/kthread.c:412 [inline] kthreadd+0x60d/0x810 kernel/kthread.c:765 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 Freed by task 61: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3f/0x80 mm/kasan/common.c:68 kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:579 poison_slab_object mm/kasan/common.c:247 [inline] __kasan_slab_free+0x59/0x70 mm/kasan/common.c:264 kasan_slab_free include/linux/kasan.h:230 [inline] slab_free_h ---truncated---

In the Linux kernel, the following vulnerability has been resolved: ksmbd: add refcnt to ksmbd_conn struct When sending an oplock break request, opinfo->conn is used, But freed ->conn can be used on multichannel. This patch add a reference count to the ksmbd_conn struct so that it can be freed when it is no longer used.

In the Linux kernel, the following vulnerability has been resolved: scsi: pm80xx: Set phy->enable_completion only when we wait for it pm8001_phy_control() populates the enable_completion pointer with a stack address, sends a PHY_LINK_RESET / PHY_HARD_RESET, waits 300 ms, and returns. The problem arises when a phy control response comes late. After 300 ms the pm8001_phy_control() function returns and the passed enable_completion stack address is no longer valid. Late phy control response invokes complete() on a dangling enable_completion pointer which leads to a kernel crash.

In the Linux kernel, the following vulnerability has been resolved: crypto: iaa - Fix potential use after free bug The free_device_compression_mode(iaa_device, device_mode) function frees "device_mode" but it iss passed to iaa_compression_modes[i]->free() a few lines later resulting in a use after free. The good news is that, so far as I can tell, nothing implements the ->free() function and the use after free happens in dead code. But, with this fix, when something does implement it, we'll be ready. :)

In the Linux kernel, the following vulnerability has been resolved: nilfs2: fix missing cleanup on rollforward recovery error In an error injection test of a routine for mount-time recovery, KASAN found a use-after-free bug. It turned out that if data recovery was performed using partial logs created by dsync writes, but an error occurred before starting the log writer to create a recovered checkpoint, the inodes whose data had been recovered were left in the ns_dirty_files list of the nilfs object and were not freed. Fix this issue by cleaning up inodes that have read the recovery data if the recovery routine fails midway before the log writer starts.

In the Linux kernel, the following vulnerability has been resolved: scsi: lpfc: Handle mailbox timeouts in lpfc_get_sfp_info The MBX_TIMEOUT return code is not handled in lpfc_get_sfp_info and the routine unconditionally frees submitted mailbox commands regardless of return status. The issue is that for MBX_TIMEOUT cases, when firmware returns SFP information at a later time, that same mailbox memory region references previously freed memory in its cmpl routine. Fix by adding checks for the MBX_TIMEOUT return code. During mailbox resource cleanup, check the mbox flag to make sure that the wait did not timeout. If the MBOX_WAKE flag is not set, then do not free the resources because it will be freed when firmware completes the mailbox at a later time in its cmpl routine. Also, increase the timeout from 30 to 60 seconds to accommodate boot scripts requiring longer timeouts.

In the Linux kernel, the following vulnerability has been resolved: xen: privcmd: Fix possible access to a freed kirqfd instance Nothing prevents simultaneous ioctl calls to privcmd_irqfd_assign() and privcmd_irqfd_deassign(). If that happens, it is possible that a kirqfd created and added to the irqfds_list by privcmd_irqfd_assign() may get removed by another thread executing privcmd_irqfd_deassign(), while the former is still using it after dropping the locks. This can lead to a situation where an already freed kirqfd instance may be accessed and cause kernel oops. Use SRCU locking to prevent the same, as is done for the KVM implementation for irqfds.

In the Linux kernel, the following vulnerability has been resolved: cgroup/cpuset: Prevent UAF in proc_cpuset_show() An UAF can happen when /proc/cpuset is read as reported in [1]. This can be reproduced by the following methods: 1.add an mdelay(1000) before acquiring the cgroup_lock In the cgroup_path_ns function. 2.$cat /proc/<pid>/cpuset repeatly. 3.$mount -t cgroup -o cpuset cpuset /sys/fs/cgroup/cpuset/ $umount /sys/fs/cgroup/cpuset/ repeatly. The race that cause this bug can be shown as below: (umount) | (cat /proc/<pid>/cpuset) css_release | proc_cpuset_show css_release_work_fn | css = task_get_css(tsk, cpuset_cgrp_id); css_free_rwork_fn | cgroup_path_ns(css->cgroup, ...); cgroup_destroy_root | mutex_lock(&cgroup_mutex); rebind_subsystems | cgroup_free_root | | // cgrp was freed, UAF | cgroup_path_ns_locked(cgrp,..); When the cpuset is initialized, the root node top_cpuset.css.cgrp will point to &cgrp_dfl_root.cgrp. In cgroup v1, the mount operation will allocate cgroup_root, and top_cpuset.css.cgrp will point to the allocated &cgroup_root.cgrp. When the umount operation is executed, top_cpuset.css.cgrp will be rebound to &cgrp_dfl_root.cgrp. The problem is that when rebinding to cgrp_dfl_root, there are cases where the cgroup_root allocated by setting up the root for cgroup v1 is cached. This could lead to a Use-After-Free (UAF) if it is subsequently freed. The descendant cgroups of cgroup v1 can only be freed after the css is released. However, the css of the root will never be released, yet the cgroup_root should be freed when it is unmounted. This means that obtaining a reference to the css of the root does not guarantee that css.cgrp->root will not be freed. Fix this problem by using rcu_read_lock in proc_cpuset_show(). As cgroup_root is kfree_rcu after commit d23b5c577715 ("cgroup: Make operations on the cgroup root_list RCU safe"), css->cgroup won't be freed during the critical section. To call cgroup_path_ns_locked, css_set_lock is needed, so it is safe to replace task_get_css with task_css. [1] https://syzkaller.appspot.com/bug?extid=9b1ff7be974a403aa4cd

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: ionic: fix kernel panic in XDP_TX action In the XDP_TX path, ionic driver sends a packet to the TX path with rx page and corresponding dma address. After tx is done, ionic_tx_clean() frees that page. But RX ring buffer isn't reset to NULL. So, it uses a freed page, which causes kernel panic. BUG: unable to handle page fault for address: ffff8881576c110c PGD 773801067 P4D 773801067 PUD 87f086067 PMD 87efca067 PTE 800ffffea893e060 Oops: Oops: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC KASAN NOPTI CPU: 1 PID: 25 Comm: ksoftirqd/1 Not tainted 6.9.0+ #11 Hardware name: ASUS System Product Name/PRIME Z690-P D4, BIOS 0603 11/01/2021 RIP: 0010:bpf_prog_f0b8caeac1068a55_balancer_ingress+0x3b/0x44f Code: 00 53 41 55 41 56 41 57 b8 01 00 00 00 48 8b 5f 08 4c 8b 77 00 4c 89 f7 48 83 c7 0e 48 39 d8 RSP: 0018:ffff888104e6fa28 EFLAGS: 00010283 RAX: 0000000000000002 RBX: ffff8881576c1140 RCX: 0000000000000002 RDX: ffffffffc0051f64 RSI: ffffc90002d33048 RDI: ffff8881576c110e RBP: ffff888104e6fa88 R08: 0000000000000000 R09: ffffed1027a04a23 R10: 0000000000000000 R11: 0000000000000000 R12: ffff8881b03a21a8 R13: ffff8881589f800f R14: ffff8881576c1100 R15: 00000001576c1100 FS: 0000000000000000(0000) GS:ffff88881ae00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffff8881576c110c CR3: 0000000767a90000 CR4: 00000000007506f0 PKRU: 55555554 Call Trace: <TASK> ? __die+0x20/0x70 ? page_fault_oops+0x254/0x790 ? __pfx_page_fault_oops+0x10/0x10 ? __pfx_is_prefetch.constprop.0+0x10/0x10 ? search_bpf_extables+0x165/0x260 ? fixup_exception+0x4a/0x970 ? exc_page_fault+0xcb/0xe0 ? asm_exc_page_fault+0x22/0x30 ? 0xffffffffc0051f64 ? bpf_prog_f0b8caeac1068a55_balancer_ingress+0x3b/0x44f ? do_raw_spin_unlock+0x54/0x220 ionic_rx_service+0x11ab/0x3010 [ionic 9180c3001ab627d82bbc5f3ebe8a0decaf6bb864] ? ionic_tx_clean+0x29b/0xc60 [ionic 9180c3001ab627d82bbc5f3ebe8a0decaf6bb864] ? __pfx_ionic_tx_clean+0x10/0x10 [ionic 9180c3001ab627d82bbc5f3ebe8a0decaf6bb864] ? __pfx_ionic_rx_service+0x10/0x10 [ionic 9180c3001ab627d82bbc5f3ebe8a0decaf6bb864] ? ionic_tx_cq_service+0x25d/0xa00 [ionic 9180c3001ab627d82bbc5f3ebe8a0decaf6bb864] ? __pfx_ionic_rx_service+0x10/0x10 [ionic 9180c3001ab627d82bbc5f3ebe8a0decaf6bb864] ionic_cq_service+0x69/0x150 [ionic 9180c3001ab627d82bbc5f3ebe8a0decaf6bb864] ionic_txrx_napi+0x11a/0x540 [ionic 9180c3001ab627d82bbc5f3ebe8a0decaf6bb864] __napi_poll.constprop.0+0xa0/0x440 net_rx_action+0x7e7/0xc30 ? __pfx_net_rx_action+0x10/0x10

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.

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: genirq/irqdesc: Prevent use-after-free in irq_find_at_or_after() irq_find_at_or_after() dereferences the interrupt descriptor which is returned by mt_find() while neither holding sparse_irq_lock nor RCU read lock, which means the descriptor can be freed between mt_find() and the dereference: CPU0 CPU1 desc = mt_find() delayed_free_desc(desc) irq_desc_get_irq(desc) The use-after-free is reported by KASAN: Call trace: irq_get_next_irq+0x58/0x84 show_stat+0x638/0x824 seq_read_iter+0x158/0x4ec proc_reg_read_iter+0x94/0x12c vfs_read+0x1e0/0x2c8 Freed by task 4471: slab_free_freelist_hook+0x174/0x1e0 __kmem_cache_free+0xa4/0x1dc kfree+0x64/0x128 irq_kobj_release+0x28/0x3c kobject_put+0xcc/0x1e0 delayed_free_desc+0x14/0x2c rcu_do_batch+0x214/0x720 Guard the access with a RCU read lock section.

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.

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]

A flaw was found in the Linux kernel's implementation of GRO in versions before 5.2. This flaw allows an attacker with local access to crash the system.

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

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 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.

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: 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: 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: 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

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']