In the Linux kernel, the following vulnerability has been resolved: f2fs: fix to avoid panic in f2fs_evict_inode As syzbot [1] reported as below: R10: 0000000000000100 R11: 0000000000000206 R12: 00007ffe17473450 R13: 00007f28b1c10854 R14: 000000000000dae5 R15: 00007ffe17474520 </TASK> ---[ end trace 0000000000000000 ]--- ================================================================== BUG: KASAN: use-after-free in __list_del_entry_valid+0xa6/0x130 lib/list_debug.c:62 Read of size 8 at addr ffff88812d962278 by task syz-executor/564 CPU: 1 PID: 564 Comm: syz-executor Tainted: G W 6.1.129-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Call Trace: <TASK> __dump_stack+0x21/0x24 lib/dump_stack.c:88 dump_stack_lvl+0xee/0x158 lib/dump_stack.c:106 print_address_description+0x71/0x210 mm/kasan/report.c:316 print_report+0x4a/0x60 mm/kasan/report.c:427 kasan_report+0x122/0x150 mm/kasan/report.c:531 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report_generic.c:351 __list_del_entry_valid+0xa6/0x130 lib/list_debug.c:62 __list_del_entry include/linux/list.h:134 [inline] list_del_init include/linux/list.h:206 [inline] f2fs_inode_synced+0xf7/0x2e0 fs/f2fs/super.c:1531 f2fs_update_inode+0x74/0x1c40 fs/f2fs/inode.c:585 f2fs_update_inode_page+0x137/0x170 fs/f2fs/inode.c:703 f2fs_write_inode+0x4ec/0x770 fs/f2fs/inode.c:731 write_inode fs/fs-writeback.c:1460 [inline] __writeback_single_inode+0x4a0/0xab0 fs/fs-writeback.c:1677 writeback_single_inode+0x221/0x8b0 fs/fs-writeback.c:1733 sync_inode_metadata+0xb6/0x110 fs/fs-writeback.c:2789 f2fs_sync_inode_meta+0x16d/0x2a0 fs/f2fs/checkpoint.c:1159 block_operations fs/f2fs/checkpoint.c:1269 [inline] f2fs_write_checkpoint+0xca3/0x2100 fs/f2fs/checkpoint.c:1658 kill_f2fs_super+0x231/0x390 fs/f2fs/super.c:4668 deactivate_locked_super+0x98/0x100 fs/super.c:332 deactivate_super+0xaf/0xe0 fs/super.c:363 cleanup_mnt+0x45f/0x4e0 fs/namespace.c:1186 __cleanup_mnt+0x19/0x20 fs/namespace.c:1193 task_work_run+0x1c6/0x230 kernel/task_work.c:203 exit_task_work include/linux/task_work.h:39 [inline] do_exit+0x9fb/0x2410 kernel/exit.c:871 do_group_exit+0x210/0x2d0 kernel/exit.c:1021 __do_sys_exit_group kernel/exit.c:1032 [inline] __se_sys_exit_group kernel/exit.c:1030 [inline] __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1030 x64_sys_call+0x7b4/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:232 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f28b1b8e169 Code: Unable to access opcode bytes at 0x7f28b1b8e13f. RSP: 002b:00007ffe174710a8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 00007f28b1c10879 RCX: 00007f28b1b8e169 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000001 RBP: 0000000000000002 R08: 00007ffe1746ee47 R09: 00007ffe17472360 R10: 0000000000000009 R11: 0000000000000246 R12: 00007ffe17472360 R13: 00007f28b1c10854 R14: 000000000000dae5 R15: 00007ffe17474520 </TASK> Allocated by task 569: kasan_save_stack mm/kasan/common.c:45 [inline] kasan_set_track+0x4b/0x70 mm/kasan/common.c:52 kasan_save_alloc_info+0x25/0x30 mm/kasan/generic.c:505 __kasan_slab_alloc+0x72/0x80 mm/kasan/common.c:328 kasan_slab_alloc include/linux/kasan.h:201 [inline] slab_post_alloc_hook+0x4f/0x2c0 mm/slab.h:737 slab_alloc_node mm/slub.c:3398 [inline] slab_alloc mm/slub.c:3406 [inline] __kmem_cache_alloc_lru mm/slub.c:3413 [inline] kmem_cache_alloc_lru+0x104/0x220 mm/slub.c:3429 alloc_inode_sb include/linux/fs.h:3245 [inline] f2fs_alloc_inode+0x2d/0x340 fs/f2fs/super.c:1419 alloc_inode fs/inode.c:261 [inline] iget_locked+0x186/0x880 fs/inode.c:1373 f2fs_iget+0x55/0x4c60 fs/f2fs/inode.c:483 f2fs_lookup+0x366/0xab0 fs/f2fs/namei.c:487 __lookup_slow+0x2a3/0x3d0 fs/namei.c:1690 lookup_slow+0x57/0x70 fs/namei.c:1707 walk_component+0x2e6/0x410 fs/namei ---truncated---

In the Linux kernel, the following vulnerability has been resolved: drm/nouveau: prime: fix ttm_bo_delayed_delete oops Fix an oops in ttm_bo_delayed_delete which results from dererencing a dangling pointer: Oops: general protection fault, probably for non-canonical address 0x6b6b6b6b6b6b6b7b: 0000 [#1] PREEMPT SMP CPU: 4 UID: 0 PID: 1082 Comm: kworker/u65:2 Not tainted 6.14.0-rc4-00267-g505460b44513-dirty #216 Hardware name: LENOVO 82N6/LNVNB161216, BIOS GKCN65WW 01/16/2024 Workqueue: ttm ttm_bo_delayed_delete [ttm] RIP: 0010:dma_resv_iter_first_unlocked+0x55/0x290 Code: 31 f6 48 c7 c7 00 2b fa aa e8 97 bd 52 ff e8 a2 c1 53 00 5a 85 c0 74 48 e9 88 01 00 00 4c 89 63 20 4d 85 e4 0f 84 30 01 00 00 <41> 8b 44 24 10 c6 43 2c 01 48 89 df 89 43 28 e8 97 fd ff ff 4c 8b RSP: 0018:ffffbf9383473d60 EFLAGS: 00010202 RAX: 0000000000000001 RBX: ffffbf9383473d88 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffbf9383473d78 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 6b6b6b6b6b6b6b6b R13: ffffa003bbf78580 R14: ffffa003a6728040 R15: 00000000000383cc FS: 0000000000000000(0000) GS:ffffa00991c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000758348024dd0 CR3: 000000012c259000 CR4: 0000000000f50ef0 PKRU: 55555554 Call Trace: <TASK> ? __die_body.cold+0x19/0x26 ? die_addr+0x3d/0x70 ? exc_general_protection+0x159/0x460 ? asm_exc_general_protection+0x27/0x30 ? dma_resv_iter_first_unlocked+0x55/0x290 dma_resv_wait_timeout+0x56/0x100 ttm_bo_delayed_delete+0x69/0xb0 [ttm] process_one_work+0x217/0x5c0 worker_thread+0x1c8/0x3d0 ? apply_wqattrs_cleanup.part.0+0xc0/0xc0 kthread+0x10b/0x240 ? kthreads_online_cpu+0x140/0x140 ret_from_fork+0x40/0x70 ? kthreads_online_cpu+0x140/0x140 ret_from_fork_asm+0x11/0x20 </TASK> The cause of this is: - drm_prime_gem_destroy calls dma_buf_put(dma_buf) which releases the reference to the shared dma_buf. The reference count is 0, so the dma_buf is destroyed, which in turn decrements the corresponding amdgpu_bo reference count to 0, and the amdgpu_bo is destroyed - calling drm_gem_object_release then dma_resv_fini (which destroys the reservation object), then finally freeing the amdgpu_bo. - nouveau_bo obj->bo.base.resv is now a dangling pointer to the memory formerly allocated to the amdgpu_bo. - nouveau_gem_object_del calls ttm_bo_put(&nvbo->bo) which calls ttm_bo_release, which schedules ttm_bo_delayed_delete. - ttm_bo_delayed_delete runs and dereferences the dangling resv pointer, resulting in a general protection fault. Fix this by moving the drm_prime_gem_destroy call from nouveau_gem_object_del to nouveau_bo_del_ttm. This ensures that it will be run after ttm_bo_delayed_delete.

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: 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: qlcnic: prevent ->dcb use-after-free on qlcnic_dcb_enable() failure adapter->dcb would get silently freed inside qlcnic_dcb_enable() in case qlcnic_dcb_attach() would return an error, which always happens under OOM conditions. This would lead to use-after-free because both of the existing callers invoke qlcnic_dcb_get_info() on the obtained pointer, which is potentially freed at that point. Propagate errors from qlcnic_dcb_enable(), and instead free the dcb pointer at callsite using qlcnic_dcb_free(). This also removes the now unused qlcnic_clear_dcb_ops() helper, which was a simple wrapper around kfree() also causing memory leaks for partially initialized dcb. Found by Linux Verification Center (linuxtesting.org) with the SVACE static analysis tool.

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.

In the Linux kernel, the following vulnerability has been resolved: usb: gadget: Fix use-after-free bug by not setting udc->dev.driver The syzbot fuzzer found a use-after-free bug: BUG: KASAN: use-after-free in dev_uevent+0x712/0x780 drivers/base/core.c:2320 Read of size 8 at addr ffff88802b934098 by task udevd/3689 CPU: 2 PID: 3689 Comm: udevd Not tainted 5.17.0-rc4-syzkaller-00229-g4f12b742eb2b #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014 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 dev_uevent+0x712/0x780 drivers/base/core.c:2320 uevent_show+0x1b8/0x380 drivers/base/core.c:2391 dev_attr_show+0x4b/0x90 drivers/base/core.c:2094 Although the bug manifested in the driver core, the real cause was a race with the gadget core. dev_uevent() does: if (dev->driver) add_uevent_var(env, "DRIVER=%s", dev->driver->name); and between the test and the dereference of dev->driver, the gadget core sets dev->driver to NULL. The race wouldn't occur if the gadget core registered its devices on a real bus, using the standard synchronization techniques of the driver core. However, it's not necessary to make such a large change in order to fix this bug; all we need to do is make sure that udc->dev.driver is always NULL. In fact, there is no reason for udc->dev.driver ever to be set to anything, let alone to the value it currently gets: the address of the gadget's driver. After all, a gadget driver only knows how to manage a gadget, not how to manage a UDC. This patch simply removes the statements in the gadget core that touch udc->dev.driver.

An issue was discovered in the Linux kernel 5.10.x before 5.10.155. A use-after-free in io_sqpoll_wait_sq in fs/io_uring.c allows an attacker to crash the kernel, resulting in denial of service. finish_wait can be skipped. An attack can occur in some situations by forking a process and then quickly terminating it. NOTE: later kernel versions, such as the 5.15 longterm series, substantially changed the implementation of io_sqpoll_wait_sq.

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: 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: 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: 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]

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---

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 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.

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: net/mlx5e: Fix crash caused by calling __xfrm_state_delete() twice The km.state is not checked in driver's delayed work. When xfrm_state_check_expire() is called, the state can be reset to XFRM_STATE_EXPIRED, even if it is XFRM_STATE_DEAD already. This happens when xfrm state is deleted, but not freed yet. As __xfrm_state_delete() is called again in xfrm timer, the following crash occurs. To fix this issue, skip xfrm_state_check_expire() if km.state is not XFRM_STATE_VALID. Oops: general protection fault, probably for non-canonical address 0xdead000000000108: 0000 [#1] SMP CPU: 5 UID: 0 PID: 7448 Comm: kworker/u102:2 Not tainted 6.11.0-rc2+ #1 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014 Workqueue: mlx5e_ipsec: eth%d mlx5e_ipsec_handle_sw_limits [mlx5_core] RIP: 0010:__xfrm_state_delete+0x3d/0x1b0 Code: 0f 84 8b 01 00 00 48 89 fd c6 87 c8 00 00 00 05 48 8d bb 40 10 00 00 e8 11 04 1a 00 48 8b 95 b8 00 00 00 48 8b 85 c0 00 00 00 <48> 89 42 08 48 89 10 48 8b 55 10 48 b8 00 01 00 00 00 00 ad de 48 RSP: 0018:ffff88885f945ec8 EFLAGS: 00010246 RAX: dead000000000122 RBX: ffffffff82afa940 RCX: 0000000000000036 RDX: dead000000000100 RSI: 0000000000000000 RDI: ffffffff82afb980 RBP: ffff888109a20340 R08: ffff88885f945ea0 R09: 0000000000000000 R10: 0000000000000000 R11: ffff88885f945ff8 R12: 0000000000000246 R13: ffff888109a20340 R14: ffff88885f95f420 R15: ffff88885f95f400 FS: 0000000000000000(0000) GS:ffff88885f940000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f2163102430 CR3: 00000001128d6001 CR4: 0000000000370eb0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <IRQ> ? die_addr+0x33/0x90 ? exc_general_protection+0x1a2/0x390 ? asm_exc_general_protection+0x22/0x30 ? __xfrm_state_delete+0x3d/0x1b0 ? __xfrm_state_delete+0x2f/0x1b0 xfrm_timer_handler+0x174/0x350 ? __xfrm_state_delete+0x1b0/0x1b0 __hrtimer_run_queues+0x121/0x270 hrtimer_run_softirq+0x88/0xd0 handle_softirqs+0xcc/0x270 do_softirq+0x3c/0x50 </IRQ> <TASK> __local_bh_enable_ip+0x47/0x50 mlx5e_ipsec_handle_sw_limits+0x7d/0x90 [mlx5_core] process_one_work+0x137/0x2d0 worker_thread+0x28d/0x3a0 ? rescuer_thread+0x480/0x480 kthread+0xb8/0xe0 ? kthread_park+0x80/0x80 ret_from_fork+0x2d/0x50 ? kthread_park+0x80/0x80 ret_from_fork_asm+0x11/0x20 </TASK>

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: ACPICA: Refuse to evaluate a method if arguments are missing As reported in [1], a platform firmware update that increased the number of method parameters and forgot to update a least one of its callers, caused ACPICA to crash due to use-after-free. Since this a result of a clear AML issue that arguably cannot be fixed up by the interpreter (it cannot produce missing data out of thin air), address it by making ACPICA refuse to evaluate a method if the caller attempts to pass fewer arguments than expected to it.

In the Linux kernel, the following vulnerability has been resolved: wifi: ath12k: fix node corruption in ar->arvifs list In current WLAN recovery code flow, ath12k_core_halt() only reinitializes the "arvifs" list head. This will cause the list node immediately following the list head to become an invalid list node. Because the prev of that node still points to the list head "arvifs", but the next of the list head "arvifs" no longer points to that list node. When a WLAN recovery occurs during the execution of a vif removal, and it happens before the spin_lock_bh(&ar->data_lock) in ath12k_mac_vdev_delete(), list_del() will detect the previously mentioned situation, thereby triggering a kernel panic. The fix is to remove and reinitialize all vif list nodes from the list head "arvifs" during WLAN halt. The reinitialization is to make the list nodes valid, ensuring that the list_del() in ath12k_mac_vdev_delete() can execute normally. Call trace: __list_del_entry_valid_or_report+0xd4/0x100 (P) ath12k_mac_remove_link_interface.isra.0+0xf8/0x2e4 [ath12k] ath12k_scan_vdev_clean_work+0x40/0x164 [ath12k] cfg80211_wiphy_work+0xfc/0x100 process_one_work+0x164/0x2d0 worker_thread+0x254/0x380 kthread+0xfc/0x100 ret_from_fork+0x10/0x20 The change is mostly copied from the ath11k patch: https://lore.kernel.org/all/20250320053145.3445187-1-quic_stonez@quicinc.com/ Tested-on: QCN9274 hw2.0 PCI WLAN.WBE.1.4.1-00199-QCAHKSWPL_SILICONZ-1

mm/rmap.c in the Linux kernel before 5.19.7 has a use-after-free related to leaf anon_vma double reuse.

In drivers/media/dvb-core/dmxdev.c in the Linux kernel through 5.19.10, there is a use-after-free caused by refcount races, affecting dvb_demux_open and dvb_dmxdev_release.

A use-after-free(UAF) vulnerability was found in function 'vmw_execbuf_tie_context' in drivers/gpu/vmxgfx/vmxgfx_execbuf.c in Linux kernel's vmwgfx driver with device file '/dev/dri/renderD128 (or Dxxx)'. This flaw allows a local attacker with a user account on the system to gain privilege, causing a denial of service(DoS).

A use-after-free(UAF) vulnerability was found in function 'vmw_cmd_res_check' in drivers/gpu/vmxgfx/vmxgfx_execbuf.c in Linux kernel's vmwgfx driver with device file '/dev/dri/renderD128 (or Dxxx)'. This flaw allows a local attacker with a user account on the system to gain privilege, causing a denial of service(DoS).

A flaw was found in the Linux kernel’s networking code. A use-after-free was found in the way the sch_sfb enqueue function used the socket buffer (SKB) cb field after the same SKB had been enqueued (and freed) into a child qdisc. This flaw allows a local, unprivileged user to crash the system, causing a denial of service.

In the Linux kernel, the following vulnerability has been resolved: vdpa: fix use-after-free on vp_vdpa_remove When vp_vdpa driver is unbind, vp_vdpa is freed in vdpa_unregister_device and then vp_vdpa->mdev.pci_dev is dereferenced in vp_modern_remove, triggering use-after-free. Call Trace of unbinding driver free vp_vdpa : do_syscall_64 vfs_write kernfs_fop_write_iter device_release_driver_internal pci_device_remove vp_vdpa_remove vdpa_unregister_device kobject_release device_release kfree Call Trace of dereference vp_vdpa->mdev.pci_dev: vp_modern_remove pci_release_selected_regions pci_release_region pci_resource_len pci_resource_end (dev)->resource[(bar)].end

In the Linux kernel, the following vulnerability has been resolved: mm/migrate_device: don't add folio to be freed to LRU in migrate_device_finalize() If migration succeeded, we called folio_migrate_flags()->mem_cgroup_migrate() to migrate the memcg from the old to the new folio. This will set memcg_data of the old folio to 0. Similarly, if migration failed, memcg_data of the dst folio is left unset. If we call folio_putback_lru() on such folios (memcg_data == 0), we will add the folio to be freed to the LRU, making memcg code unhappy. Running the hmm selftests: # ./hmm-tests ... # RUN hmm.hmm_device_private.migrate ... [ 102.078007][T14893] page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x7ff27d200 pfn:0x13cc00 [ 102.079974][T14893] anon flags: 0x17ff00000020018(uptodate|dirty|swapbacked|node=0|zone=2|lastcpupid=0x7ff) [ 102.082037][T14893] raw: 017ff00000020018 dead000000000100 dead000000000122 ffff8881353896c9 [ 102.083687][T14893] raw: 00000007ff27d200 0000000000000000 00000001ffffffff 0000000000000000 [ 102.085331][T14893] page dumped because: VM_WARN_ON_ONCE_FOLIO(!memcg && !mem_cgroup_disabled()) [ 102.087230][T14893] ------------[ cut here ]------------ [ 102.088279][T14893] WARNING: CPU: 0 PID: 14893 at ./include/linux/memcontrol.h:726 folio_lruvec_lock_irqsave+0x10e/0x170 [ 102.090478][T14893] Modules linked in: [ 102.091244][T14893] CPU: 0 UID: 0 PID: 14893 Comm: hmm-tests Not tainted 6.13.0-09623-g6c216bc522fd #151 [ 102.093089][T14893] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-2.fc40 04/01/2014 [ 102.094848][T14893] RIP: 0010:folio_lruvec_lock_irqsave+0x10e/0x170 [ 102.096104][T14893] Code: ... [ 102.099908][T14893] RSP: 0018:ffffc900236c37b0 EFLAGS: 00010293 [ 102.101152][T14893] RAX: 0000000000000000 RBX: ffffea0004f30000 RCX: ffffffff8183f426 [ 102.102684][T14893] RDX: ffff8881063cb880 RSI: ffffffff81b8117f RDI: ffff8881063cb880 [ 102.104227][T14893] RBP: 0000000000000000 R08: 0000000000000005 R09: 0000000000000000 [ 102.105757][T14893] R10: 0000000000000001 R11: 0000000000000002 R12: ffffc900236c37d8 [ 102.107296][T14893] R13: ffff888277a2bcb0 R14: 000000000000001f R15: 0000000000000000 [ 102.108830][T14893] FS: 00007ff27dbdd740(0000) GS:ffff888277a00000(0000) knlGS:0000000000000000 [ 102.110643][T14893] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 102.111924][T14893] CR2: 00007ff27d400000 CR3: 000000010866e000 CR4: 0000000000750ef0 [ 102.113478][T14893] PKRU: 55555554 [ 102.114172][T14893] Call Trace: [ 102.114805][T14893] <TASK> [ 102.115397][T14893] ? folio_lruvec_lock_irqsave+0x10e/0x170 [ 102.116547][T14893] ? __warn.cold+0x110/0x210 [ 102.117461][T14893] ? folio_lruvec_lock_irqsave+0x10e/0x170 [ 102.118667][T14893] ? report_bug+0x1b9/0x320 [ 102.119571][T14893] ? handle_bug+0x54/0x90 [ 102.120494][T14893] ? exc_invalid_op+0x17/0x50 [ 102.121433][T14893] ? asm_exc_invalid_op+0x1a/0x20 [ 102.122435][T14893] ? __wake_up_klogd.part.0+0x76/0xd0 [ 102.123506][T14893] ? dump_page+0x4f/0x60 [ 102.124352][T14893] ? folio_lruvec_lock_irqsave+0x10e/0x170 [ 102.125500][T14893] folio_batch_move_lru+0xd4/0x200 [ 102.126577][T14893] ? __pfx_lru_add+0x10/0x10 [ 102.127505][T14893] __folio_batch_add_and_move+0x391/0x720 [ 102.128633][T14893] ? __pfx_lru_add+0x10/0x10 [ 102.129550][T14893] folio_putback_lru+0x16/0x80 [ 102.130564][T14893] migrate_device_finalize+0x9b/0x530 [ 102.131640][T14893] dmirror_migrate_to_device.constprop.0+0x7c5/0xad0 [ 102.133047][T14893] dmirror_fops_unlocked_ioctl+0x89b/0xc80 Likely, nothing else goes wrong: putting the last folio reference will remove the folio from the LRU again. So besides memcg complaining, adding the folio to be freed to the LRU is just an unnecessary step. The new flow resembles what we have in migrate_folio_move(): add the dst to the lru, rem ---truncated---

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: block: RCU protect disk->conv_zones_bitmap Ensure that a disk revalidation changing the conventional zones bitmap of a disk does not cause invalid memory references when using the disk_zone_is_conv() helper by RCU protecting the disk->conv_zones_bitmap pointer. disk_zone_is_conv() is modified to operate under the RCU read lock and the function disk_set_conv_zones_bitmap() is added to update a disk conv_zones_bitmap pointer using rcu_replace_pointer() with the disk zone_wplugs_lock spinlock held. disk_free_zone_resources() is modified to call disk_update_zone_resources() with a NULL bitmap pointer to free the disk conv_zones_bitmap. disk_set_conv_zones_bitmap() is also used in disk_update_zone_resources() to set the new (revalidated) bitmap and free the old one.

In the Linux kernel, the following vulnerability has been resolved: virtio_net: correct netdev_tx_reset_queue() invocation point When virtnet_close is followed by virtnet_open, some TX completions can possibly remain unconsumed, until they are finally processed during the first NAPI poll after the netdev_tx_reset_queue(), resulting in a crash [1]. Commit b96ed2c97c79 ("virtio_net: move netdev_tx_reset_queue() call before RX napi enable") was not sufficient to eliminate all BQL crash cases for virtio-net. This issue can be reproduced with the latest net-next master by running: `while :; do ip l set DEV down; ip l set DEV up; done` under heavy network TX load from inside the machine. netdev_tx_reset_queue() can actually be dropped from virtnet_open path; the device is not stopped in any case. For BQL core part, it's just like traffic nearly ceases to exist for some period. For stall detector added to BQL, even if virtnet_close could somehow lead to some TX completions delayed for long, followed by virtnet_open, we can just take it as stall as mentioned in commit 6025b9135f7a ("net: dqs: add NIC stall detector based on BQL"). Note also that users can still reset stall_max via sysfs. So, drop netdev_tx_reset_queue() from virtnet_enable_queue_pair(). This eliminates the BQL crashes. As a result, netdev_tx_reset_queue() is now explicitly required in freeze/restore path. This patch adds it to immediately after free_unused_bufs(), following the rule of thumb: netdev_tx_reset_queue() should follow any SKB freeing not followed by netdev_tx_completed_queue(). This seems the most consistent and streamlined approach, and now netdev_tx_reset_queue() runs whenever free_unused_bufs() is done. [1]: ------------[ cut here ]------------ kernel BUG at lib/dynamic_queue_limits.c:99! Oops: invalid opcode: 0000 [#1] PREEMPT SMP NOPTI CPU: 7 UID: 0 PID: 1598 Comm: ip Tainted: G N 6.12.0net-next_main+ #2 Tainted: [N]=TEST Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), \ BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014 RIP: 0010:dql_completed+0x26b/0x290 Code: b7 c2 49 89 e9 44 89 da 89 c6 4c 89 d7 e8 ed 17 47 00 58 65 ff 0d 4d 27 90 7e 0f 85 fd fe ff ff e8 ea 53 8d ff e9 f3 fe ff ff <0f> 0b 01 d2 44 89 d1 29 d1 ba 00 00 00 00 0f 48 ca e9 28 ff ff ff RSP: 0018:ffffc900002b0d08 EFLAGS: 00010297 RAX: 0000000000000000 RBX: ffff888102398c80 RCX: 0000000080190009 RDX: 0000000000000000 RSI: 000000000000006a RDI: 0000000000000000 RBP: ffff888102398c00 R08: 0000000000000000 R09: 0000000000000000 R10: 00000000000000ca R11: 0000000000015681 R12: 0000000000000001 R13: ffffc900002b0d68 R14: ffff88811115e000 R15: ffff8881107aca40 FS: 00007f41ded69500(0000) GS:ffff888667dc0000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000556ccc2dc1a0 CR3: 0000000104fd8003 CR4: 0000000000772ef0 PKRU: 55555554 Call Trace: <IRQ> ? die+0x32/0x80 ? do_trap+0xd9/0x100 ? dql_completed+0x26b/0x290 ? dql_completed+0x26b/0x290 ? do_error_trap+0x6d/0xb0 ? dql_completed+0x26b/0x290 ? exc_invalid_op+0x4c/0x60 ? dql_completed+0x26b/0x290 ? asm_exc_invalid_op+0x16/0x20 ? dql_completed+0x26b/0x290 __free_old_xmit+0xff/0x170 [virtio_net] free_old_xmit+0x54/0xc0 [virtio_net] virtnet_poll+0xf4/0xe30 [virtio_net] ? __update_load_avg_cfs_rq+0x264/0x2d0 ? update_curr+0x35/0x260 ? reweight_entity+0x1be/0x260 __napi_poll.constprop.0+0x28/0x1c0 net_rx_action+0x329/0x420 ? enqueue_hrtimer+0x35/0x90 ? trace_hardirqs_on+0x1d/0x80 ? kvm_sched_clock_read+0xd/0x20 ? sched_clock+0xc/0x30 ? kvm_sched_clock_read+0xd/0x20 ? sched_clock+0xc/0x30 ? sched_clock_cpu+0xd/0x1a0 handle_softirqs+0x138/0x3e0 do_softirq.part.0+0x89/0xc0 </IRQ> <TASK> __local_bh_enable_ip+0xa7/0xb0 virtnet_open+0xc8/0x310 [virtio_net] __dev_open+0xfa/0x1b0 __dev_change_flags+0x1de/0x250 dev_change_flags+0x22/0x60 do_setlink.isra.0+0x2df/0x10b0 ? rtnetlink_rcv_msg+0x34f/0x3f0 ? netlink_rcv_skb+0x54/0x100 ? netlink_unicas ---truncated---

In the Linux kernel, the following vulnerability has been resolved: block, bfq: fix possible UAF for bfqq->bic with merge chain 1) initial state, three tasks: Process 1 Process 2 Process 3 (BIC1) (BIC2) (BIC3) | Λ | Λ | Λ | | | | | | V | V | V | bfqq1 bfqq2 bfqq3 process ref: 1 1 1 2) bfqq1 merged to bfqq2: Process 1 Process 2 Process 3 (BIC1) (BIC2) (BIC3) | | | Λ \--------------\| | | V V | bfqq1--------->bfqq2 bfqq3 process ref: 0 2 1 3) bfqq2 merged to bfqq3: Process 1 Process 2 Process 3 (BIC1) (BIC2) (BIC3) here -> Λ | | \--------------\ \-------------\| V V bfqq1--------->bfqq2---------->bfqq3 process ref: 0 1 3 In this case, IO from Process 1 will get bfqq2 from BIC1 first, and then get bfqq3 through merge chain, and finially handle IO by bfqq3. Howerver, current code will think bfqq2 is owned by BIC1, like initial state, and set bfqq2->bic to BIC1. bfq_insert_request -> by Process 1 bfqq = bfq_init_rq(rq) bfqq = bfq_get_bfqq_handle_split bfqq = bic_to_bfqq -> get bfqq2 from BIC1 bfqq->ref++ rq->elv.priv[0] = bic rq->elv.priv[1] = bfqq if (bfqq_process_refs(bfqq) == 1) bfqq->bic = bic -> record BIC1 to bfqq2 __bfq_insert_request new_bfqq = bfq_setup_cooperator -> get bfqq3 from bfqq2->new_bfqq bfqq_request_freed(bfqq) new_bfqq->ref++ rq->elv.priv[1] = new_bfqq -> handle IO by bfqq3 Fix the problem by checking bfqq is from merge chain fist. And this might fix a following problem reported by our syzkaller(unreproducible): ================================================================== BUG: KASAN: slab-use-after-free in bfq_do_early_stable_merge block/bfq-iosched.c:5692 [inline] BUG: KASAN: slab-use-after-free in bfq_do_or_sched_stable_merge block/bfq-iosched.c:5805 [inline] BUG: KASAN: slab-use-after-free in bfq_get_queue+0x25b0/0x2610 block/bfq-iosched.c:5889 Write of size 1 at addr ffff888123839eb8 by task kworker/0:1H/18595 CPU: 0 PID: 18595 Comm: kworker/0:1H Tainted: G L 6.6.0-07439-gba2303cacfda #6 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014 Workqueue: kblockd blk_mq_requeue_work Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x91/0xf0 lib/dump_stack.c:106 print_address_description mm/kasan/report.c:364 [inline] print_report+0x10d/0x610 mm/kasan/report.c:475 kasan_report+0x8e/0xc0 mm/kasan/report.c:588 bfq_do_early_stable_merge block/bfq-iosched.c:5692 [inline] bfq_do_or_sched_stable_merge block/bfq-iosched.c:5805 [inline] bfq_get_queue+0x25b0/0x2610 block/bfq-iosched.c:5889 bfq_get_bfqq_handle_split+0x169/0x5d0 block/bfq-iosched.c:6757 bfq_init_rq block/bfq-iosched.c:6876 [inline] bfq_insert_request block/bfq-iosched.c:6254 [inline] bfq_insert_requests+0x1112/0x5cf0 block/bfq-iosched.c:6304 blk_mq_insert_request+0x290/0x8d0 block/blk-mq.c:2593 blk_mq_requeue_work+0x6bc/0xa70 block/blk-mq.c:1502 process_one_work kernel/workqueue.c:2627 [inline] process_scheduled_works+0x432/0x13f0 kernel/workqueue.c:2700 worker_thread+0x6f2/0x1160 kernel/workqueue.c:2781 kthread+0x33c/0x440 kernel/kthread.c:388 ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1b/0x30 arch/x86/entry/entry_64.S:305 </TASK> Allocated by task 20776: kasan_save_stack+0x20/0x40 mm/kasan/common.c:45 kasan_set_track+0x25/0x30 mm/kasan/common.c:52 __kasan_slab_alloc+0x87/0x90 mm/kasan/common.c:328 kasan_slab_alloc include/linux/kasan.h:188 [inline] slab_post_alloc_hook mm/slab.h:763 [inline] slab_alloc_node mm/slub.c:3458 [inline] kmem_cache_alloc_node+0x1a4/0x6f0 mm/slub.c:3503 ioc_create_icq block/blk-ioc.c:370 [inline] ---truncated---

In the Linux kernel, the following vulnerability has been resolved: smb: client: fix NULL ptr deref in crypto_aead_setkey() Neither SMB3.0 or SMB3.02 supports encryption negotiate context, so when SMB2_GLOBAL_CAP_ENCRYPTION flag is set in the negotiate response, the client uses AES-128-CCM as the default cipher. See MS-SMB2 3.3.5.4. Commit b0abcd65ec54 ("smb: client: fix UAF in async decryption") added a @server->cipher_type check to conditionally call smb3_crypto_aead_allocate(), but that check would always be false as @server->cipher_type is unset for SMB3.02. Fix the following KASAN splat by setting @server->cipher_type for SMB3.02 as well. mount.cifs //srv/share /mnt -o vers=3.02,seal,... BUG: KASAN: null-ptr-deref in crypto_aead_setkey+0x2c/0x130 Read of size 8 at addr 0000000000000020 by task mount.cifs/1095 CPU: 1 UID: 0 PID: 1095 Comm: mount.cifs Not tainted 6.12.0 #1 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-3.fc41 04/01/2014 Call Trace: <TASK> dump_stack_lvl+0x5d/0x80 ? crypto_aead_setkey+0x2c/0x130 kasan_report+0xda/0x110 ? crypto_aead_setkey+0x2c/0x130 crypto_aead_setkey+0x2c/0x130 crypt_message+0x258/0xec0 [cifs] ? __asan_memset+0x23/0x50 ? __pfx_crypt_message+0x10/0x10 [cifs] ? mark_lock+0xb0/0x6a0 ? hlock_class+0x32/0xb0 ? mark_lock+0xb0/0x6a0 smb3_init_transform_rq+0x352/0x3f0 [cifs] ? lock_acquire.part.0+0xf4/0x2a0 smb_send_rqst+0x144/0x230 [cifs] ? __pfx_smb_send_rqst+0x10/0x10 [cifs] ? hlock_class+0x32/0xb0 ? smb2_setup_request+0x225/0x3a0 [cifs] ? __pfx_cifs_compound_last_callback+0x10/0x10 [cifs] compound_send_recv+0x59b/0x1140 [cifs] ? __pfx_compound_send_recv+0x10/0x10 [cifs] ? __create_object+0x5e/0x90 ? hlock_class+0x32/0xb0 ? do_raw_spin_unlock+0x9a/0xf0 cifs_send_recv+0x23/0x30 [cifs] SMB2_tcon+0x3ec/0xb30 [cifs] ? __pfx_SMB2_tcon+0x10/0x10 [cifs] ? lock_acquire.part.0+0xf4/0x2a0 ? __pfx_lock_release+0x10/0x10 ? do_raw_spin_trylock+0xc6/0x120 ? lock_acquire+0x3f/0x90 ? _get_xid+0x16/0xd0 [cifs] ? __pfx_SMB2_tcon+0x10/0x10 [cifs] ? cifs_get_smb_ses+0xcdd/0x10a0 [cifs] cifs_get_smb_ses+0xcdd/0x10a0 [cifs] ? __pfx_cifs_get_smb_ses+0x10/0x10 [cifs] ? cifs_get_tcp_session+0xaa0/0xca0 [cifs] cifs_mount_get_session+0x8a/0x210 [cifs] dfs_mount_share+0x1b0/0x11d0 [cifs] ? __pfx___lock_acquire+0x10/0x10 ? __pfx_dfs_mount_share+0x10/0x10 [cifs] ? lock_acquire.part.0+0xf4/0x2a0 ? find_held_lock+0x8a/0xa0 ? hlock_class+0x32/0xb0 ? lock_release+0x203/0x5d0 cifs_mount+0xb3/0x3d0 [cifs] ? do_raw_spin_trylock+0xc6/0x120 ? __pfx_cifs_mount+0x10/0x10 [cifs] ? lock_acquire+0x3f/0x90 ? find_nls+0x16/0xa0 ? smb3_update_mnt_flags+0x372/0x3b0 [cifs] cifs_smb3_do_mount+0x1e2/0xc80 [cifs] ? __pfx_vfs_parse_fs_string+0x10/0x10 ? __pfx_cifs_smb3_do_mount+0x10/0x10 [cifs] smb3_get_tree+0x1bf/0x330 [cifs] vfs_get_tree+0x4a/0x160 path_mount+0x3c1/0xfb0 ? kasan_quarantine_put+0xc7/0x1d0 ? __pfx_path_mount+0x10/0x10 ? kmem_cache_free+0x118/0x3e0 ? user_path_at+0x74/0xa0 __x64_sys_mount+0x1a6/0x1e0 ? __pfx___x64_sys_mount+0x10/0x10 ? mark_held_locks+0x1a/0x90 do_syscall_64+0xbb/0x1d0 entry_SYSCALL_64_after_hwframe+0x77/0x7f

In the Linux kernel, the following vulnerability has been resolved: iommu/s390: Implement blocking domain This fixes a crash when surprise hot-unplugging a PCI device. This crash happens because during hot-unplug __iommu_group_set_domain_nofail() attaching the default domain fails when the platform no longer recognizes the device as it has already been removed and we end up with a NULL domain pointer and UAF. This is exactly the case referred to in the second comment in __iommu_device_set_domain() and just as stated there if we can instead attach the blocking domain the UAF is prevented as this can handle the already removed device. Implement the blocking domain to use this handling. With this change, the crash is fixed but we still hit a warning attempting to change DMA ownership on a blocked device.

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: ACPI: battery: Fix possible crash when unregistering a battery hook When a battery hook returns an error when adding a new battery, then the battery hook is automatically unregistered. However the battery hook provider cannot know that, so it will later call battery_hook_unregister() on the already unregistered battery hook, resulting in a crash. Fix this by using the list head to mark already unregistered battery hooks as already being unregistered so that they can be ignored by battery_hook_unregister().

In the Linux kernel, the following vulnerability has been resolved: drm/xe: Don't free job in TDR Freeing job in TDR is not safe as TDR can pass the run_job thread resulting in UAF. It is only safe for free job to naturally be called by the scheduler. Rather free job in TDR, add to pending list. (cherry picked from commit ea2f6a77d0c40d97f4a4dc93fee4afe15d94926d)

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: 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/ncsi: Disable the ncsi work before freeing the associated structure The work function can run after the ncsi device is freed, resulting in use-after-free bugs or kernel panic.

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: mptcp: pm: fix UaF read in mptcp_pm_nl_rm_addr_or_subflow Syzkaller reported this splat: ================================================================== BUG: KASAN: slab-use-after-free in mptcp_pm_nl_rm_addr_or_subflow+0xb44/0xcc0 net/mptcp/pm_netlink.c:881 Read of size 4 at addr ffff8880569ac858 by task syz.1.2799/14662 CPU: 0 UID: 0 PID: 14662 Comm: syz.1.2799 Not tainted 6.12.0-rc2-syzkaller-00307-g36c254515dc6 #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 Call Trace: <TASK> __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:377 [inline] print_report+0xc3/0x620 mm/kasan/report.c:488 kasan_report+0xd9/0x110 mm/kasan/report.c:601 mptcp_pm_nl_rm_addr_or_subflow+0xb44/0xcc0 net/mptcp/pm_netlink.c:881 mptcp_pm_nl_rm_subflow_received net/mptcp/pm_netlink.c:914 [inline] mptcp_nl_remove_id_zero_address+0x305/0x4a0 net/mptcp/pm_netlink.c:1572 mptcp_pm_nl_del_addr_doit+0x5c9/0x770 net/mptcp/pm_netlink.c:1603 genl_family_rcv_msg_doit+0x202/0x2f0 net/netlink/genetlink.c:1115 genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline] genl_rcv_msg+0x565/0x800 net/netlink/genetlink.c:1210 netlink_rcv_skb+0x165/0x410 net/netlink/af_netlink.c:2551 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1219 netlink_unicast_kernel net/netlink/af_netlink.c:1331 [inline] netlink_unicast+0x53c/0x7f0 net/netlink/af_netlink.c:1357 netlink_sendmsg+0x8b8/0xd70 net/netlink/af_netlink.c:1901 sock_sendmsg_nosec net/socket.c:729 [inline] __sock_sendmsg net/socket.c:744 [inline] ____sys_sendmsg+0x9ae/0xb40 net/socket.c:2607 ___sys_sendmsg+0x135/0x1e0 net/socket.c:2661 __sys_sendmsg+0x117/0x1f0 net/socket.c:2690 do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline] __do_fast_syscall_32+0x73/0x120 arch/x86/entry/common.c:386 do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411 entry_SYSENTER_compat_after_hwframe+0x84/0x8e RIP: 0023:0xf7fe4579 Code: b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00 RSP: 002b:00000000f574556c EFLAGS: 00000296 ORIG_RAX: 0000000000000172 RAX: ffffffffffffffda RBX: 000000000000000b RCX: 0000000020000140 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000296 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 </TASK> Allocated by task 5387: kasan_save_stack+0x33/0x60 mm/kasan/common.c:47 kasan_save_track+0x14/0x30 mm/kasan/common.c:68 poison_kmalloc_redzone mm/kasan/common.c:377 [inline] __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:394 kmalloc_noprof include/linux/slab.h:878 [inline] kzalloc_noprof include/linux/slab.h:1014 [inline] subflow_create_ctx+0x87/0x2a0 net/mptcp/subflow.c:1803 subflow_ulp_init+0xc3/0x4d0 net/mptcp/subflow.c:1956 __tcp_set_ulp net/ipv4/tcp_ulp.c:146 [inline] tcp_set_ulp+0x326/0x7f0 net/ipv4/tcp_ulp.c:167 mptcp_subflow_create_socket+0x4ae/0x10a0 net/mptcp/subflow.c:1764 __mptcp_subflow_connect+0x3cc/0x1490 net/mptcp/subflow.c:1592 mptcp_pm_create_subflow_or_signal_addr+0xbda/0x23a0 net/mptcp/pm_netlink.c:642 mptcp_pm_nl_fully_established net/mptcp/pm_netlink.c:650 [inline] mptcp_pm_nl_work+0x3a1/0x4f0 net/mptcp/pm_netlink.c:943 mptcp_worker+0x15a/0x1240 net/mptcp/protocol.c:2777 process_one_work+0x958/0x1b30 kernel/workqueue.c:3229 process_scheduled_works kernel/workqueue.c:3310 [inline] worker_thread+0x6c8/0xf00 kernel/workqueue.c:3391 kthread+0x2c1/0x3a0 kernel/kthread.c:389 ret_from_fork+0x45/0x80 arch/x86/ke ---truncated---

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.

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. :)

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: 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

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.