In the Linux kernel, the following vulnerability has been resolved: bpf, sockmap: Fix race between element replace and close() Element replace (with a socket different from the one stored) may race with socket's close() link popping & unlinking. __sock_map_delete() unconditionally unrefs the (wrong) element: // set map[0] = s0 map_update_elem(map, 0, s0) // drop fd of s0 close(s0) sock_map_close() lock_sock(sk) (s0!) sock_map_remove_links(sk) link = sk_psock_link_pop() sock_map_unlink(sk, link) sock_map_delete_from_link // replace map[0] with s1 map_update_elem(map, 0, s1) sock_map_update_elem (s1!) lock_sock(sk) sock_map_update_common psock = sk_psock(sk) spin_lock(&stab->lock) osk = stab->sks[idx] sock_map_add_link(..., &stab->sks[idx]) sock_map_unref(osk, &stab->sks[idx]) psock = sk_psock(osk) sk_psock_put(sk, psock) if (refcount_dec_and_test(&psock)) sk_psock_drop(sk, psock) spin_unlock(&stab->lock) unlock_sock(sk) __sock_map_delete spin_lock(&stab->lock) sk = *psk // s1 replaced s0; sk == s1 if (!sk_test || sk_test == sk) // sk_test (s0) != sk (s1); no branch sk = xchg(psk, NULL) if (sk) sock_map_unref(sk, psk) // unref s1; sks[idx] will dangle psock = sk_psock(sk) sk_psock_put(sk, psock) if (refcount_dec_and_test()) sk_psock_drop(sk, psock) spin_unlock(&stab->lock) release_sock(sk) Then close(map) enqueues bpf_map_free_deferred, which finally calls sock_map_free(). This results in some refcount_t warnings along with a KASAN splat [1]. Fix __sock_map_delete(), do not allow sock_map_unref() on elements that may have been replaced. [1]: BUG: KASAN: slab-use-after-free in sock_map_free+0x10e/0x330 Write of size 4 at addr ffff88811f5b9100 by task kworker/u64:12/1063 CPU: 14 UID: 0 PID: 1063 Comm: kworker/u64:12 Not tainted 6.12.0+ #125 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014 Workqueue: events_unbound bpf_map_free_deferred Call Trace: <TASK> dump_stack_lvl+0x68/0x90 print_report+0x174/0x4f6 kasan_report+0xb9/0x190 kasan_check_range+0x10f/0x1e0 sock_map_free+0x10e/0x330 bpf_map_free_deferred+0x173/0x320 process_one_work+0x846/0x1420 worker_thread+0x5b3/0xf80 kthread+0x29e/0x360 ret_from_fork+0x2d/0x70 ret_from_fork_asm+0x1a/0x30 </TASK> Allocated by task 1202: kasan_save_stack+0x1e/0x40 kasan_save_track+0x10/0x30 __kasan_slab_alloc+0x85/0x90 kmem_cache_alloc_noprof+0x131/0x450 sk_prot_alloc+0x5b/0x220 sk_alloc+0x2c/0x870 unix_create1+0x88/0x8a0 unix_create+0xc5/0x180 __sock_create+0x241/0x650 __sys_socketpair+0x1ce/0x420 __x64_sys_socketpair+0x92/0x100 do_syscall_64+0x93/0x180 entry_SYSCALL_64_after_hwframe+0x76/0x7e Freed by task 46: kasan_save_stack+0x1e/0x40 kasan_save_track+0x10/0x30 kasan_save_free_info+0x37/0x60 __kasan_slab_free+0x4b/0x70 kmem_cache_free+0x1a1/0x590 __sk_destruct+0x388/0x5a0 sk_psock_destroy+0x73e/0xa50 process_one_work+0x846/0x1420 worker_thread+0x5b3/0xf80 kthread+0x29e/0x360 ret_from_fork+0x2d/0x70 ret_from_fork_asm+0x1a/0x30 The bu ---truncated---

In the Linux kernel, the following vulnerability has been resolved: net: seeq: Fix use after free vulnerability in ether3 Driver Due to Race Condition In the ether3_probe function, a timer is initialized with a callback function ether3_ledoff, bound to &prev(dev)->timer. Once the timer is started, there is a risk of a race condition if the module or device is removed, triggering the ether3_remove function to perform cleanup. The sequence of operations that may lead to a UAF bug is as follows: CPU0 CPU1 | ether3_ledoff ether3_remove | free_netdev(dev); | put_devic | kfree(dev); | | ether3_outw(priv(dev)->regs.config2 |= CFG2_CTRLO, REG_CONFIG2); | // use dev Fix it by ensuring that the timer is canceled before proceeding with the cleanup in ether3_remove.

In the Linux kernel, the following vulnerability has been resolved: jfs: Fix uaf in dbFreeBits [syzbot reported] ================================================================== BUG: KASAN: slab-use-after-free in __mutex_lock_common kernel/locking/mutex.c:587 [inline] BUG: KASAN: slab-use-after-free in __mutex_lock+0xfe/0xd70 kernel/locking/mutex.c:752 Read of size 8 at addr ffff8880229254b0 by task syz-executor357/5216 CPU: 0 UID: 0 PID: 5216 Comm: syz-executor357 Not tainted 6.11.0-rc3-syzkaller-00156-gd7a5aa4b3c00 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/27/2024 Call Trace: <TASK> __dump_stack lib/dump_stack.c:93 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:119 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 __mutex_lock_common kernel/locking/mutex.c:587 [inline] __mutex_lock+0xfe/0xd70 kernel/locking/mutex.c:752 dbFreeBits+0x7ea/0xd90 fs/jfs/jfs_dmap.c:2390 dbFreeDmap fs/jfs/jfs_dmap.c:2089 [inline] dbFree+0x35b/0x680 fs/jfs/jfs_dmap.c:409 dbDiscardAG+0x8a9/0xa20 fs/jfs/jfs_dmap.c:1650 jfs_ioc_trim+0x433/0x670 fs/jfs/jfs_discard.c:100 jfs_ioctl+0x2d0/0x3e0 fs/jfs/ioctl.c:131 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:907 [inline] __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:893 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 Freed by task 5218: 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+0xe0/0x150 mm/kasan/common.c:240 __kasan_slab_free+0x37/0x60 mm/kasan/common.c:256 kasan_slab_free include/linux/kasan.h:184 [inline] slab_free_hook mm/slub.c:2252 [inline] slab_free mm/slub.c:4473 [inline] kfree+0x149/0x360 mm/slub.c:4594 dbUnmount+0x11d/0x190 fs/jfs/jfs_dmap.c:278 jfs_mount_rw+0x4ac/0x6a0 fs/jfs/jfs_mount.c:247 jfs_remount+0x3d1/0x6b0 fs/jfs/super.c:454 reconfigure_super+0x445/0x880 fs/super.c:1083 vfs_cmd_reconfigure fs/fsopen.c:263 [inline] vfs_fsconfig_locked fs/fsopen.c:292 [inline] __do_sys_fsconfig fs/fsopen.c:473 [inline] __se_sys_fsconfig+0xb6e/0xf80 fs/fsopen.c:345 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f [Analysis] There are two paths (dbUnmount and jfs_ioc_trim) that generate race condition when accessing bmap, which leads to the occurrence of uaf. Use the lock s_umount to synchronize them, in order to avoid uaf caused by race condition.

In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix user-after-free from session log off There is racy issue between smb2 session log off and smb2 session setup. It will cause user-after-free from session log off. This add session_lock when setting SMB2_SESSION_EXPIRED and referece count to session struct not to free session while it is being used.

In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix slab-use-after-free in ksmbd_smb2_session_create There is a race condition between ksmbd_smb2_session_create and ksmbd_expire_session. This patch add missing sessions_table_lock while adding/deleting session from global session table.

In the Linux kernel, the following vulnerability has been resolved: i3c: master: cdns: Fix use after free vulnerability in cdns_i3c_master Driver Due to Race Condition In the cdns_i3c_master_probe function, &master->hj_work is bound with cdns_i3c_master_hj. And cdns_i3c_master_interrupt can call cnds_i3c_master_demux_ibis function to start the work. If we remove the module which will call cdns_i3c_master_remove to make cleanup, it will free master->base through i3c_master_unregister while the work mentioned above will be used. The sequence of operations that may lead to a UAF bug is as follows: CPU0 CPU1 | cdns_i3c_master_hj cdns_i3c_master_remove | i3c_master_unregister(&master->base) | device_unregister(&master->dev) | device_release | //free master->base | | i3c_master_do_daa(&master->base) | //use master->base Fix it by ensuring that the work is canceled before proceeding with the cleanup in cdns_i3c_master_remove.

In the Linux kernel, the following vulnerability has been resolved: nfsd: fix race between laundromat and free_stateid There is a race between laundromat handling of revoked delegations and a client sending free_stateid operation. Laundromat thread finds that delegation has expired and needs to be revoked so it marks the delegation stid revoked and it puts it on a reaper list but then it unlock the state lock and the actual delegation revocation happens without the lock. Once the stid is marked revoked a racing free_stateid processing thread does the following (1) it calls list_del_init() which removes it from the reaper list and (2) frees the delegation stid structure. The laundromat thread ends up not calling the revoke_delegation() function for this particular delegation but that means it will no release the lock lease that exists on the file. Now, a new open for this file comes in and ends up finding that lease list isn't empty and calls nfsd_breaker_owns_lease() which ends up trying to derefence a freed delegation stateid. Leading to the followint use-after-free KASAN warning: kernel: ================================================================== kernel: BUG: KASAN: slab-use-after-free in nfsd_breaker_owns_lease+0x140/0x160 [nfsd] kernel: Read of size 8 at addr ffff0000e73cd0c8 by task nfsd/6205 kernel: kernel: CPU: 2 UID: 0 PID: 6205 Comm: nfsd Kdump: loaded Not tainted 6.11.0-rc7+ #9 kernel: Hardware name: Apple Inc. Apple Virtualization Generic Platform, BIOS 2069.0.0.0.0 08/03/2024 kernel: Call trace: kernel: dump_backtrace+0x98/0x120 kernel: show_stack+0x1c/0x30 kernel: dump_stack_lvl+0x80/0xe8 kernel: print_address_description.constprop.0+0x84/0x390 kernel: print_report+0xa4/0x268 kernel: kasan_report+0xb4/0xf8 kernel: __asan_report_load8_noabort+0x1c/0x28 kernel: nfsd_breaker_owns_lease+0x140/0x160 [nfsd] kernel: nfsd_file_do_acquire+0xb3c/0x11d0 [nfsd] kernel: nfsd_file_acquire_opened+0x84/0x110 [nfsd] kernel: nfs4_get_vfs_file+0x634/0x958 [nfsd] kernel: nfsd4_process_open2+0xa40/0x1a40 [nfsd] kernel: nfsd4_open+0xa08/0xe80 [nfsd] kernel: nfsd4_proc_compound+0xb8c/0x2130 [nfsd] kernel: nfsd_dispatch+0x22c/0x718 [nfsd] kernel: svc_process_common+0x8e8/0x1960 [sunrpc] kernel: svc_process+0x3d4/0x7e0 [sunrpc] kernel: svc_handle_xprt+0x828/0xe10 [sunrpc] kernel: svc_recv+0x2cc/0x6a8 [sunrpc] kernel: nfsd+0x270/0x400 [nfsd] kernel: kthread+0x288/0x310 kernel: ret_from_fork+0x10/0x20 This patch proposes a fixed that's based on adding 2 new additional stid's sc_status values that help coordinate between the laundromat and other operations (nfsd4_free_stateid() and nfsd4_delegreturn()). First to make sure, that once the stid is marked revoked, it is not removed by the nfsd4_free_stateid(), the laundromat take a reference on the stateid. Then, coordinating whether the stid has been put on the cl_revoked list or we are processing FREE_STATEID and need to make sure to remove it from the list, each check that state and act accordingly. If laundromat has added to the cl_revoke list before the arrival of FREE_STATEID, then nfsd4_free_stateid() knows to remove it from the list. If nfsd4_free_stateid() finds that operations arrived before laundromat has placed it on cl_revoke list, it marks the state freed and then laundromat will no longer add it to the list. Also, for nfsd4_delegreturn() when looking for the specified stid, we need to access stid that are marked removed or freeable, it means the laundromat has started processing it but hasn't finished and this delegreturn needs to return nfserr_deleg_revoked and not nfserr_bad_stateid. The latter will not trigger a FREE_STATEID and the lack of it will leave this stid on the cl_revoked list indefinitely.

In the Linux kernel, the following vulnerability has been resolved: media: venus: fix use after free bug in venus_remove due to race condition in venus_probe, core->work is bound with venus_sys_error_handler, which is used to handle error. The code use core->sys_err_done to make sync work. The core->work is started in venus_event_notify. If we call venus_remove, there might be an unfished work. The possible sequence is as follows: CPU0 CPU1 |venus_sys_error_handler venus_remove | hfi_destroy | venus_hfi_destroy | kfree(hdev); | |hfi_reinit |venus_hfi_queues_reinit |//use hdev Fix it by canceling the work in venus_remove.

In the Linux kernel, the following vulnerability has been resolved: nbd: fix race between timeout and normal completion If request timetout is handled by nbd_requeue_cmd(), normal completion has to be stopped for avoiding to complete this requeued request, other use-after-free can be triggered. Fix the race by clearing NBD_CMD_INFLIGHT in nbd_requeue_cmd(), meantime make sure that cmd->lock is grabbed for clearing the flag and the requeue.

In the Linux kernel, the following vulnerability has been resolved: i3c: master: svc: Fix use after free vulnerability in svc_i3c_master Driver Due to Race Condition In the svc_i3c_master_probe function, &master->hj_work is bound with svc_i3c_master_hj_work, &master->ibi_work is bound with svc_i3c_master_ibi_work. And svc_i3c_master_ibi_work can start the hj_work, svc_i3c_master_irq_handler can start the ibi_work. If we remove the module which will call svc_i3c_master_remove to make cleanup, it will free master->base through i3c_master_unregister while the work mentioned above will be used. The sequence of operations that may lead to a UAF bug is as follows: CPU0 CPU1 | svc_i3c_master_hj_work svc_i3c_master_remove | i3c_master_unregister(&master->base)| device_unregister(&master->dev) | device_release | //free master->base | | i3c_master_do_daa(&master->base) | //use master->base Fix it by ensuring that the work is canceled before proceeding with the cleanup in svc_i3c_master_remove.

In the Linux kernel, the following vulnerability has been resolved: arm64/sve: Discard stale CPU state when handling SVE traps The logic for handling SVE traps manipulates saved FPSIMD/SVE state incorrectly, and a race with preemption can result in a task having TIF_SVE set and TIF_FOREIGN_FPSTATE clear even though the live CPU state is stale (e.g. with SVE traps enabled). This has been observed to result in warnings from do_sve_acc() where SVE traps are not expected while TIF_SVE is set: | if (test_and_set_thread_flag(TIF_SVE)) | WARN_ON(1); /* SVE access shouldn't have trapped */ Warnings of this form have been reported intermittently, e.g. https://lore.kernel.org/linux-arm-kernel/CA+G9fYtEGe_DhY2Ms7+L7NKsLYUomGsgqpdBj+QwDLeSg=JhGg@mail.gmail.com/ https://lore.kernel.org/linux-arm-kernel/000000000000511e9a060ce5a45c@google.com/ The race can occur when the SVE trap handler is preempted before and after manipulating the saved FPSIMD/SVE state, starting and ending on the same CPU, e.g. | void do_sve_acc(unsigned long esr, struct pt_regs *regs) | { | // Trap on CPU 0 with TIF_SVE clear, SVE traps enabled | // task->fpsimd_cpu is 0. | // per_cpu_ptr(&fpsimd_last_state, 0) is task. | | ... | | // Preempted; migrated from CPU 0 to CPU 1. | // TIF_FOREIGN_FPSTATE is set. | | get_cpu_fpsimd_context(); | | if (test_and_set_thread_flag(TIF_SVE)) | WARN_ON(1); /* SVE access shouldn't have trapped */ | | sve_init_regs() { | if (!test_thread_flag(TIF_FOREIGN_FPSTATE)) { | ... | } else { | fpsimd_to_sve(current); | current->thread.fp_type = FP_STATE_SVE; | } | } | | put_cpu_fpsimd_context(); | | // Preempted; migrated from CPU 1 to CPU 0. | // task->fpsimd_cpu is still 0 | // If per_cpu_ptr(&fpsimd_last_state, 0) is still task then: | // - Stale HW state is reused (with SVE traps enabled) | // - TIF_FOREIGN_FPSTATE is cleared | // - A return to userspace skips HW state restore | } Fix the case where the state is not live and TIF_FOREIGN_FPSTATE is set by calling fpsimd_flush_task_state() to detach from the saved CPU state. This ensures that a subsequent context switch will not reuse the stale CPU state, and will instead set TIF_FOREIGN_FPSTATE, forcing the new state to be reloaded from memory prior to a return to userspace.

In the Linux kernel, the following vulnerability has been resolved: btrfs: fix race setting file private on concurrent lseek using same fd When doing concurrent lseek(2) system calls against the same file descriptor, using multiple threads belonging to the same process, we have a short time window where a race happens and can result in a memory leak. The race happens like this: 1) A program opens a file descriptor for a file and then spawns two threads (with the pthreads library for example), lets call them task A and task B; 2) Task A calls lseek with SEEK_DATA or SEEK_HOLE and ends up at file.c:find_desired_extent() while holding a read lock on the inode; 3) At the start of find_desired_extent(), it extracts the file's private_data pointer into a local variable named 'private', which has a value of NULL; 4) Task B also calls lseek with SEEK_DATA or SEEK_HOLE, locks the inode in shared mode and enters file.c:find_desired_extent(), where it also extracts file->private_data into its local variable 'private', which has a NULL value; 5) Because it saw a NULL file private, task A allocates a private structure and assigns to the file structure; 6) Task B also saw a NULL file private so it also allocates its own file private and then assigns it to the same file structure, since both tasks are using the same file descriptor. At this point we leak the private structure allocated by task A. Besides the memory leak, there's also the detail that both tasks end up using the same cached state record in the private structure (struct btrfs_file_private::llseek_cached_state), which can result in a use-after-free problem since one task can free it while the other is still using it (only one task took a reference count on it). Also, sharing the cached state is not a good idea since it could result in incorrect results in the future - right now it should not be a problem because it end ups being used only in extent-io-tree.c:count_range_bits() where we do range validation before using the cached state. Fix this by protecting the private assignment and check of a file while holding the inode's spinlock and keep track of the task that allocated the private, so that it's used only by that task in order to prevent user-after-free issues with the cached state record as well as potentially using it incorrectly in the future.

In the Linux kernel, the following vulnerability has been resolved: mptcp: pm: Fix uaf in __timer_delete_sync There are two paths to access mptcp_pm_del_add_timer, result in a race condition: CPU1 CPU2 ==== ==== net_rx_action napi_poll netlink_sendmsg __napi_poll netlink_unicast process_backlog netlink_unicast_kernel __netif_receive_skb genl_rcv __netif_receive_skb_one_core netlink_rcv_skb NF_HOOK genl_rcv_msg ip_local_deliver_finish genl_family_rcv_msg ip_protocol_deliver_rcu genl_family_rcv_msg_doit tcp_v4_rcv mptcp_pm_nl_flush_addrs_doit tcp_v4_do_rcv mptcp_nl_remove_addrs_list tcp_rcv_established mptcp_pm_remove_addrs_and_subflows tcp_data_queue remove_anno_list_by_saddr mptcp_incoming_options mptcp_pm_del_add_timer mptcp_pm_del_add_timer kfree(entry) In remove_anno_list_by_saddr(running on CPU2), after leaving the critical zone protected by "pm.lock", the entry will be released, which leads to the occurrence of uaf in the mptcp_pm_del_add_timer(running on CPU1). Keeping a reference to add_timer inside the lock, and calling sk_stop_timer_sync() with this reference, instead of "entry->add_timer". Move list_del(&entry->list) to mptcp_pm_del_add_timer and inside the pm lock, do not directly access any members of the entry outside the pm lock, which can avoid similar "entry->x" uaf.

In the Linux kernel, the following vulnerability has been resolved: net/mlx5: Fix a race on command flush flow Fix a refcount use after free warning due to a race on command entry. Such race occurs when one of the commands releases its last refcount and frees its index and entry while another process running command flush flow takes refcount to this command entry. The process which handles commands flush may see this command as needed to be flushed if the other process released its refcount but didn't release the index yet. Fix it by adding the needed spin lock. It fixes the following warning trace: refcount_t: addition on 0; use-after-free. WARNING: CPU: 11 PID: 540311 at lib/refcount.c:25 refcount_warn_saturate+0x80/0xe0 ... RIP: 0010:refcount_warn_saturate+0x80/0xe0 ... Call Trace: <TASK> mlx5_cmd_trigger_completions+0x293/0x340 [mlx5_core] mlx5_cmd_flush+0x3a/0xf0 [mlx5_core] enter_error_state+0x44/0x80 [mlx5_core] mlx5_fw_fatal_reporter_err_work+0x37/0xe0 [mlx5_core] process_one_work+0x1be/0x390 worker_thread+0x4d/0x3d0 ? rescuer_thread+0x350/0x350 kthread+0x141/0x160 ? set_kthread_struct+0x40/0x40 ret_from_fork+0x1f/0x30 </TASK>

net/xfrm/xfrm_policy.c in the Linux kernel through 4.12.3, when CONFIG_XFRM_MIGRATE is enabled, does not ensure that the dir value of xfrm_userpolicy_id is XFRM_POLICY_MAX or less, which allows local users to cause a denial of service (out-of-bounds access) or possibly have unspecified other impact via an XFRM_MSG_MIGRATE xfrm Netlink message.

Race condition in kernel/ucount.c in the Linux kernel through 4.10.2 allows local users to cause a denial of service (use-after-free and system crash) or possibly have unspecified other impact via crafted system calls that leverage certain decrement behavior that causes incorrect interaction between put_ucounts and get_ucounts.