Linux Linux Kernel vulnerabilities

In the Linux kernel, the following vulnerability has been resolved: can: xilinx_can: xcan_write_frame(): fix use-after-free of transmitted SKB can_put_echo_skb() takes ownership of the SKB and it may be freed during or after the call. However, xilinx_can xcan_write_frame() keeps using SKB after the call. Fix that by only calling can_put_echo_skb() after the code is done touching the SKB. The tx_lock is held for the entire xcan_write_frame() execution and also on the can_get_echo_skb() side so the order of operations does not matter. An earlier fix commit 3d3c817c3a40 ("can: xilinx_can: Fix usage of skb memory") did not move the can_put_echo_skb() call far enough. [mkl: add "commit" in front of sha1 in patch description] [mkl: fix indention]

In the Linux kernel, the following vulnerability has been resolved: dmaengine: idxd: Fix double free in idxd_setup_wqs() The clean up in idxd_setup_wqs() has had a couple bugs because the error handling is a bit subtle. It's simpler to just re-write it in a cleaner way. The issues here are: 1) If "idxd->max_wqs" is <= 0 then we call put_device(conf_dev) when "conf_dev" hasn't been initialized. 2) If kzalloc_node() fails then again "conf_dev" is invalid. It's either uninitialized or it points to the "conf_dev" from the previous iteration so it leads to a double free. It's better to free partial loop iterations within the loop and then the unwinding at the end can handle whole loop iterations. I also renamed the labels to describe what the goto does and not where the goto was located.

In the Linux kernel, the following vulnerability has been resolved: dmaengine: ti: edma: Fix memory allocation size for queue_priority_map Fix a critical memory allocation bug in edma_setup_from_hw() where queue_priority_map was allocated with insufficient memory. The code declared queue_priority_map as s8 (*)[2] (pointer to array of 2 s8), but allocated memory using sizeof(s8) instead of the correct size. This caused out-of-bounds memory writes when accessing: queue_priority_map[i][0] = i; queue_priority_map[i][1] = i; The bug manifested as kernel crashes with "Oops - undefined instruction" on ARM platforms (BeagleBoard-X15) during EDMA driver probe, as the memory corruption triggered kernel hardening features on Clang. Change the allocation to use sizeof(*queue_priority_map) which automatically gets the correct size for the 2D array structure.

In the Linux kernel, the following vulnerability has been resolved: dmaengine: idxd: Remove improper idxd_free The call to idxd_free() introduces a duplicate put_device() leading to a reference count underflow: refcount_t: underflow; use-after-free. WARNING: CPU: 15 PID: 4428 at lib/refcount.c:28 refcount_warn_saturate+0xbe/0x110 ... Call Trace: <TASK> idxd_remove+0xe4/0x120 [idxd] pci_device_remove+0x3f/0xb0 device_release_driver_internal+0x197/0x200 driver_detach+0x48/0x90 bus_remove_driver+0x74/0xf0 pci_unregister_driver+0x2e/0xb0 idxd_exit_module+0x34/0x7a0 [idxd] __do_sys_delete_module.constprop.0+0x183/0x280 do_syscall_64+0x54/0xd70 entry_SYSCALL_64_after_hwframe+0x76/0x7e The idxd_unregister_devices() which is invoked at the very beginning of idxd_remove(), already takes care of the necessary put_device() through the following call path: idxd_unregister_devices() -> device_unregister() -> put_device() In addition, when CONFIG_DEBUG_KOBJECT_RELEASE is enabled, put_device() may trigger asynchronous cleanup via schedule_delayed_work(). If idxd_free() is called immediately after, it can result in a use-after-free. Remove the improper idxd_free() to avoid both the refcount underflow and potential memory corruption during module unload.

In the Linux kernel, the following vulnerability has been resolved: erofs: fix runtime warning on truncate_folio_batch_exceptionals() Commit 0e2f80afcfa6("fs/dax: ensure all pages are idle prior to filesystem unmount") introduced the WARN_ON_ONCE to capture whether the filesystem has removed all DAX entries or not and applied the fix to xfs and ext4. Apply the missed fix on erofs to fix the runtime warning: [ 5.266254] ------------[ cut here ]------------ [ 5.266274] WARNING: CPU: 6 PID: 3109 at mm/truncate.c:89 truncate_folio_batch_exceptionals+0xff/0x260 [ 5.266294] Modules linked in: [ 5.266999] CPU: 6 UID: 0 PID: 3109 Comm: umount Tainted: G S 6.16.0+ #6 PREEMPT(voluntary) [ 5.267012] Tainted: [S]=CPU_OUT_OF_SPEC [ 5.267017] Hardware name: Dell Inc. OptiPlex 5000/05WXFV, BIOS 1.5.1 08/24/2022 [ 5.267024] RIP: 0010:truncate_folio_batch_exceptionals+0xff/0x260 [ 5.267076] Code: 00 00 41 39 df 7f 11 eb 78 83 c3 01 49 83 c4 08 41 39 df 74 6c 48 63 f3 48 83 fe 1f 0f 83 3c 01 00 00 43 f6 44 26 08 01 74 df <0f> 0b 4a 8b 34 22 4c 89 ef 48 89 55 90 e8 ff 54 1f 00 48 8b 55 90 [ 5.267083] RSP: 0018:ffffc900013f36c8 EFLAGS: 00010202 [ 5.267095] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 [ 5.267101] RDX: ffffc900013f3790 RSI: 0000000000000000 RDI: ffff8882a1407898 [ 5.267108] RBP: ffffc900013f3740 R08: 0000000000000000 R09: 0000000000000000 [ 5.267113] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 [ 5.267119] R13: ffff8882a1407ab8 R14: ffffc900013f3888 R15: 0000000000000001 [ 5.267125] FS: 00007aaa8b437800(0000) GS:ffff88850025b000(0000) knlGS:0000000000000000 [ 5.267132] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 5.267138] CR2: 00007aaa8b3aac10 CR3: 000000024f764000 CR4: 0000000000f52ef0 [ 5.267144] PKRU: 55555554 [ 5.267150] Call Trace: [ 5.267154] <TASK> [ 5.267181] truncate_inode_pages_range+0x118/0x5e0 [ 5.267193] ? save_trace+0x54/0x390 [ 5.267296] truncate_inode_pages_final+0x43/0x60 [ 5.267309] evict+0x2a4/0x2c0 [ 5.267339] dispose_list+0x39/0x80 [ 5.267352] evict_inodes+0x150/0x1b0 [ 5.267376] generic_shutdown_super+0x41/0x180 [ 5.267390] kill_block_super+0x1b/0x50 [ 5.267402] erofs_kill_sb+0x81/0x90 [erofs] [ 5.267436] deactivate_locked_super+0x32/0xb0 [ 5.267450] deactivate_super+0x46/0x60 [ 5.267460] cleanup_mnt+0xc3/0x170 [ 5.267475] __cleanup_mnt+0x12/0x20 [ 5.267485] task_work_run+0x5d/0xb0 [ 5.267499] exit_to_user_mode_loop+0x144/0x170 [ 5.267512] do_syscall_64+0x2b9/0x7c0 [ 5.267523] ? __lock_acquire+0x665/0x2ce0 [ 5.267535] ? __lock_acquire+0x665/0x2ce0 [ 5.267560] ? lock_acquire+0xcd/0x300 [ 5.267573] ? find_held_lock+0x31/0x90 [ 5.267582] ? mntput_no_expire+0x97/0x4e0 [ 5.267606] ? mntput_no_expire+0xa1/0x4e0 [ 5.267625] ? mntput+0x24/0x50 [ 5.267634] ? path_put+0x1e/0x30 [ 5.267647] ? do_faccessat+0x120/0x2f0 [ 5.267677] ? do_syscall_64+0x1a2/0x7c0 [ 5.267686] ? from_kgid_munged+0x17/0x30 [ 5.267703] ? from_kuid_munged+0x13/0x30 [ 5.267711] ? __do_sys_getuid+0x3d/0x50 [ 5.267724] ? do_syscall_64+0x1a2/0x7c0 [ 5.267732] ? irqentry_exit+0x77/0xb0 [ 5.267743] ? clear_bhb_loop+0x30/0x80 [ 5.267752] ? clear_bhb_loop+0x30/0x80 [ 5.267765] entry_SYSCALL_64_after_hwframe+0x76/0x7e [ 5.267772] RIP: 0033:0x7aaa8b32a9fb [ 5.267781] Code: c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 f3 0f 1e fa 31 f6 e9 05 00 00 00 0f 1f 44 00 00 f3 0f 1e fa b8 a6 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 05 c3 0f 1f 40 00 48 8b 15 e9 83 0d 00 f7 d8 [ 5.267787] RSP: 002b:00007ffd7c4c9468 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [ 5.267796] RAX: 0000000000000000 RBX: 00005a61592a8b00 RCX: 00007aaa8b32a9fb [ 5.267802] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00005a61592b2080 [ 5.267806] RBP: 00007ffd7c4c9540 R08: 00007aaa8b403b20 R09: 0000000000000020 [ 5.267812] R10: 0000000000000001 R11: 0000000000000246 R12: 00005a61592a8c00 [ 5.267817] R13: 00000000 ---truncated---

In the Linux kernel, the following vulnerability has been resolved: wifi: cfg80211: fix use-after-free in cmp_bss() Following bss_free() quirk introduced in commit 776b3580178f ("cfg80211: track hidden SSID networks properly"), adjust cfg80211_update_known_bss() to free the last beacon frame elements only if they're not shared via the corresponding 'hidden_beacon_bss' pointer.

In the Linux kernel, the following vulnerability has been resolved: wifi: mt76: mt7915: fix list corruption after hardware restart Since stations are recreated from scratch, all lists that wcids are added to must be cleared before calling ieee80211_restart_hw. Set wcid->sta = 0 for each wcid entry in order to ensure that they are not added again before they are ready.

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: vhci: Prevent use-after-free by removing debugfs files early Move the creation of debugfs files into a dedicated function, and ensure they are explicitly removed during vhci_release(), before associated data structures are freed. Previously, debugfs files such as "force_suspend", "force_wakeup", and others were created under hdev->debugfs but not removed in vhci_release(). Since vhci_release() frees the backing vhci_data structure, any access to these files after release would result in use-after-free errors. Although hdev->debugfs is later freed in hci_release_dev(), user can access files after vhci_data is freed but before hdev->debugfs is released.

In the Linux kernel, the following vulnerability has been resolved: fs: writeback: fix use-after-free in __mark_inode_dirty() An use-after-free issue occurred when __mark_inode_dirty() get the bdi_writeback that was in the progress of switching. CPU: 1 PID: 562 Comm: systemd-random- Not tainted 6.6.56-gb4403bd46a8e #1 ...... pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : __mark_inode_dirty+0x124/0x418 lr : __mark_inode_dirty+0x118/0x418 sp : ffffffc08c9dbbc0 ........ Call trace: __mark_inode_dirty+0x124/0x418 generic_update_time+0x4c/0x60 file_modified+0xcc/0xd0 ext4_buffered_write_iter+0x58/0x124 ext4_file_write_iter+0x54/0x704 vfs_write+0x1c0/0x308 ksys_write+0x74/0x10c __arm64_sys_write+0x1c/0x28 invoke_syscall+0x48/0x114 el0_svc_common.constprop.0+0xc0/0xe0 do_el0_svc+0x1c/0x28 el0_svc+0x40/0xe4 el0t_64_sync_handler+0x120/0x12c el0t_64_sync+0x194/0x198 Root cause is: systemd-random-seed kworker ---------------------------------------------------------------------- ___mark_inode_dirty inode_switch_wbs_work_fn spin_lock(&inode->i_lock); inode_attach_wb locked_inode_to_wb_and_lock_list get inode->i_wb spin_unlock(&inode->i_lock); spin_lock(&wb->list_lock) spin_lock(&inode->i_lock) inode_io_list_move_locked spin_unlock(&wb->list_lock) spin_unlock(&inode->i_lock) spin_lock(&old_wb->list_lock) inode_do_switch_wbs spin_lock(&inode->i_lock) inode->i_wb = new_wb spin_unlock(&inode->i_lock) spin_unlock(&old_wb->list_lock) wb_put_many(old_wb, nr_switched) cgwb_release old wb released wb_wakeup_delayed() accesses wb, then trigger the use-after-free issue Fix this race condition by holding inode spinlock until wb_wakeup_delayed() finished.

In the Linux kernel, the following vulnerability has been resolved: wifi: brcmfmac: fix use-after-free when rescheduling brcmf_btcoex_info work The brcmf_btcoex_detach() only shuts down the btcoex timer, if the flag timer_on is false. However, the brcmf_btcoex_timerfunc(), which runs as timer handler, sets timer_on to false. This creates critical race conditions: 1.If brcmf_btcoex_detach() is called while brcmf_btcoex_timerfunc() is executing, it may observe timer_on as false and skip the call to timer_shutdown_sync(). 2.The brcmf_btcoex_timerfunc() may then reschedule the brcmf_btcoex_info worker after the cancel_work_sync() has been executed, resulting in use-after-free bugs. The use-after-free bugs occur in two distinct scenarios, depending on the timing of when the brcmf_btcoex_info struct is freed relative to the execution of its worker thread. Scenario 1: Freed before the worker is scheduled The brcmf_btcoex_info is deallocated before the worker is scheduled. A race condition can occur when schedule_work(&bt_local->work) is called after the target memory has been freed. The sequence of events is detailed below: CPU0 | CPU1 brcmf_btcoex_detach | brcmf_btcoex_timerfunc | bt_local->timer_on = false; if (cfg->btcoex->timer_on) | ... | cancel_work_sync(); | ... | kfree(cfg->btcoex); // FREE | | schedule_work(&bt_local->work); // USE Scenario 2: Freed after the worker is scheduled The brcmf_btcoex_info is freed after the worker has been scheduled but before or during its execution. In this case, statements within the brcmf_btcoex_handler() — such as the container_of macro and subsequent dereferences of the brcmf_btcoex_info object will cause a use-after-free access. The following timeline illustrates this scenario: CPU0 | CPU1 brcmf_btcoex_detach | brcmf_btcoex_timerfunc | bt_local->timer_on = false; if (cfg->btcoex->timer_on) | ... | cancel_work_sync(); | ... | schedule_work(); // Reschedule | kfree(cfg->btcoex); // FREE | brcmf_btcoex_handler() // Worker /* | btci = container_of(....); // USE The kfree() above could | ... also occur at any point | btci-> // USE during the worker's execution| */ | To resolve the race conditions, drop the conditional check and call timer_shutdown_sync() directly. It can deactivate the timer reliably, regardless of its current state. Once stopped, the timer_on state is then set to false.

In the Linux kernel, the following vulnerability has been resolved: ptp: ocp: fix use-after-free bugs causing by ptp_ocp_watchdog The ptp_ocp_detach() only shuts down the watchdog timer if it is pending. However, if the timer handler is already running, the timer_delete_sync() is not called. This leads to race conditions where the devlink that contains the ptp_ocp is deallocated while the timer handler is still accessing it, resulting in use-after-free bugs. The following details one of the race scenarios. (thread 1) | (thread 2) ptp_ocp_remove() | ptp_ocp_detach() | ptp_ocp_watchdog() if (timer_pending(&bp->watchdog))| bp = timer_container_of() timer_delete_sync() | | devlink_free(devlink) //free | | bp-> //use Resolve this by unconditionally calling timer_delete_sync() to ensure the timer is reliably deactivated, preventing any access after free.

In the Linux kernel, the following vulnerability has been resolved: ice: fix NULL access of tx->in_use in ice_ptp_ts_irq The E810 device has support for a "low latency" firmware interface to access and read the Tx timestamps. This interface does not use the standard Tx timestamp logic, due to the latency overhead of proxying sideband command requests over the firmware AdminQ. The logic still makes use of the Tx timestamp tracking structure, ice_ptp_tx, as it uses the same "ready" bitmap to track which Tx timestamps complete. Unfortunately, the ice_ptp_ts_irq() function does not check if the tracker is initialized before its first access. This results in NULL dereference or use-after-free bugs similar to the following: [245977.278756] BUG: kernel NULL pointer dereference, address: 0000000000000000 [245977.278774] RIP: 0010:_find_first_bit+0x19/0x40 [245977.278796] Call Trace: [245977.278809] ? ice_misc_intr+0x364/0x380 [ice] This can occur if a Tx timestamp interrupt races with the driver reset logic. Fix this by only checking the in_use bitmap (and other fields) if the tracker is marked as initialized. The reset flow will clear the init field under lock before it tears the tracker down, thus preventing any use-after-free or NULL access.

In the Linux kernel, the following vulnerability has been resolved: ice: fix NULL access of tx->in_use in ice_ll_ts_intr Recent versions of the E810 firmware have support for an extra interrupt to handle report of the "low latency" Tx timestamps coming from the specialized low latency firmware interface. Instead of polling the registers, software can wait until the low latency interrupt is fired. This logic makes use of the Tx timestamp tracking structure, ice_ptp_tx, as it uses the same "ready" bitmap to track which Tx timestamps complete. Unfortunately, the ice_ll_ts_intr() function does not check if the tracker is initialized before its first access. This results in NULL dereference or use-after-free bugs similar to the issues fixed in the ice_ptp_ts_irq() function. Fix this by only checking the in_use bitmap (and other fields) if the tracker is marked as initialized. The reset flow will clear the init field under lock before it tears the tracker down, thus preventing any use-after-free or NULL access.

In the Linux kernel, the following vulnerability has been resolved: i40e: Fix potential invalid access when MAC list is empty list_first_entry() never returns NULL - if the list is empty, it still returns a pointer to an invalid object, leading to potential invalid memory access when dereferenced. Fix this by using list_first_entry_or_null instead of list_first_entry.

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: Fix use-after-free in l2cap_sock_cleanup_listen() syzbot reported the splat below without a repro. In the splat, a single thread calling bt_accept_dequeue() freed sk and touched it after that. The root cause would be the racy l2cap_sock_cleanup_listen() call added by the cited commit. bt_accept_dequeue() is called under lock_sock() except for l2cap_sock_release(). Two threads could see the same socket during the list iteration in bt_accept_dequeue(): CPU1 CPU2 (close()) ---- ---- sock_hold(sk) sock_hold(sk); lock_sock(sk) <-- block close() sock_put(sk) bt_accept_unlink(sk) sock_put(sk) <-- refcnt by bt_accept_enqueue() release_sock(sk) lock_sock(sk) sock_put(sk) bt_accept_unlink(sk) sock_put(sk) <-- last refcnt bt_accept_unlink(sk) <-- UAF Depending on the timing, the other thread could show up in the "Freed by task" part. Let's call l2cap_sock_cleanup_listen() under lock_sock() in l2cap_sock_release(). [0]: BUG: KASAN: slab-use-after-free in debug_spin_lock_before kernel/locking/spinlock_debug.c:86 [inline] BUG: KASAN: slab-use-after-free in do_raw_spin_lock+0x26f/0x2b0 kernel/locking/spinlock_debug.c:115 Read of size 4 at addr ffff88803b7eb1c4 by task syz.5.3276/16995 CPU: 3 UID: 0 PID: 16995 Comm: syz.5.3276 Not tainted syzkaller #0 PREEMPT(full) 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:378 [inline] print_report+0xcd/0x630 mm/kasan/report.c:482 kasan_report+0xe0/0x110 mm/kasan/report.c:595 debug_spin_lock_before kernel/locking/spinlock_debug.c:86 [inline] do_raw_spin_lock+0x26f/0x2b0 kernel/locking/spinlock_debug.c:115 spin_lock_bh include/linux/spinlock.h:356 [inline] release_sock+0x21/0x220 net/core/sock.c:3746 bt_accept_dequeue+0x505/0x600 net/bluetooth/af_bluetooth.c:312 l2cap_sock_cleanup_listen+0x5c/0x2a0 net/bluetooth/l2cap_sock.c:1451 l2cap_sock_release+0x5c/0x210 net/bluetooth/l2cap_sock.c:1425 __sock_release+0xb3/0x270 net/socket.c:649 sock_close+0x1c/0x30 net/socket.c:1439 __fput+0x3ff/0xb70 fs/file_table.c:468 task_work_run+0x14d/0x240 kernel/task_work.c:227 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] exit_to_user_mode_loop+0xeb/0x110 kernel/entry/common.c:43 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline] do_syscall_64+0x3f6/0x4c0 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f2accf8ebe9 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffdb6cb1378 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4 RAX: 0000000000000000 RBX: 00000000000426fb RCX: 00007f2accf8ebe9 RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003 RBP: 00007f2acd1b7da0 R08: 0000000000000001 R09: 00000012b6cb166f R10: 0000001b30e20000 R11: 0000000000000246 R12: 00007f2acd1b609c R13: 00007f2acd1b6090 R14: ffffffffffffffff R15: 00007ffdb6cb1490 </TASK> Allocated by task 5326: 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:388 [inline] __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:405 kasan_kmalloc include/linux/kasan.h:260 [inline] __do_kmalloc_node mm/slub.c:4365 [inline] __kmalloc_nopro ---truncated---