A flaw was found in the crypto subsystem of the Linux kernel before version kernel-4.15-rc4. The "null skcipher" was being dropped when each af_alg_ctx was freed instead of when the aead_tfm was freed. This can cause the null skcipher to be freed while it is still in use leading to a local user being able to crash the system or possibly escalate privileges.

In the Linux kernel, the following vulnerability has been resolved: mISDN: Fix a use after free in hfcmulti_tx() Don't dereference *sp after calling dev_kfree_skb(*sp).

kernel/ucount.c in the Linux kernel 5.14 through 5.16.4, when unprivileged user namespaces are enabled, allows a use-after-free and privilege escalation because a ucounts object can outlive its namespace.

A use-after-free vulnerability in the Linux kernel's netfilter: nf_tables component can be exploited to achieve local privilege escalation. The nft_verdict_init() function allows positive values as drop error within the hook verdict, and hence the nf_hook_slow() function can cause a double free vulnerability when NF_DROP is issued with a drop error which resembles NF_ACCEPT. We recommend upgrading past commit f342de4e2f33e0e39165d8639387aa6c19dff660.

A memory leak flaw was found in the Linux kernel’s io_uring functionality in how a user registers a buffer ring with IORING_REGISTER_PBUF_RING, mmap() it, and then frees it. This flaw allows a local user to crash or potentially escalate their privileges on the system.

io_uring use work_flags to determine which identity need to grab from the calling process to make sure it is consistent with the calling process when executing IORING_OP. Some operations are missing some types, which can lead to incorrect reference counts which can then lead to a double free. We recommend upgrading the kernel past commit df3f3bb5059d20ef094d6b2f0256c4bf4127a859

In the Linux kernel, the following vulnerability has been resolved: af_unix: Don't return OOB skb in manage_oob(). syzbot reported use-after-free in unix_stream_recv_urg(). [0] The scenario is 1. send(MSG_OOB) 2. recv(MSG_OOB) -> The consumed OOB remains in recv queue 3. send(MSG_OOB) 4. recv() -> manage_oob() returns the next skb of the consumed OOB -> This is also OOB, but unix_sk(sk)->oob_skb is not cleared 5. recv(MSG_OOB) -> unix_sk(sk)->oob_skb is used but already freed The recent commit 8594d9b85c07 ("af_unix: Don't call skb_get() for OOB skb.") uncovered the issue. If the OOB skb is consumed and the next skb is peeked in manage_oob(), we still need to check if the skb is OOB. Let's do so by falling back to the following checks in manage_oob() and add the test case in selftest. Note that we need to add a similar check for SIOCATMARK. [0]: BUG: KASAN: slab-use-after-free in unix_stream_read_actor+0xa6/0xb0 net/unix/af_unix.c:2959 Read of size 4 at addr ffff8880326abcc4 by task syz-executor178/5235 CPU: 0 UID: 0 PID: 5235 Comm: syz-executor178 Not tainted 6.11.0-rc5-syzkaller-00742-gfbdaffe41adc #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024 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 unix_stream_read_actor+0xa6/0xb0 net/unix/af_unix.c:2959 unix_stream_recv_urg+0x1df/0x320 net/unix/af_unix.c:2640 unix_stream_read_generic+0x2456/0x2520 net/unix/af_unix.c:2778 unix_stream_recvmsg+0x22b/0x2c0 net/unix/af_unix.c:2996 sock_recvmsg_nosec net/socket.c:1046 [inline] sock_recvmsg+0x22f/0x280 net/socket.c:1068 ____sys_recvmsg+0x1db/0x470 net/socket.c:2816 ___sys_recvmsg net/socket.c:2858 [inline] __sys_recvmsg+0x2f0/0x3e0 net/socket.c:2888 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 RIP: 0033:0x7f5360d6b4e9 Code: 48 83 c4 28 c3 e8 37 17 00 00 0f 1f 80 00 00 00 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 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fff29b3a458 EFLAGS: 00000246 ORIG_RAX: 000000000000002f RAX: ffffffffffffffda RBX: 00007fff29b3a638 RCX: 00007f5360d6b4e9 RDX: 0000000000002001 RSI: 0000000020000640 RDI: 0000000000000003 RBP: 00007f5360dde610 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 R13: 00007fff29b3a628 R14: 0000000000000001 R15: 0000000000000001 </TASK> Allocated by task 5235: 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:312 [inline] __kasan_slab_alloc+0x66/0x80 mm/kasan/common.c:338 kasan_slab_alloc include/linux/kasan.h:201 [inline] slab_post_alloc_hook mm/slub.c:3988 [inline] slab_alloc_node mm/slub.c:4037 [inline] kmem_cache_alloc_node_noprof+0x16b/0x320 mm/slub.c:4080 __alloc_skb+0x1c3/0x440 net/core/skbuff.c:667 alloc_skb include/linux/skbuff.h:1320 [inline] alloc_skb_with_frags+0xc3/0x770 net/core/skbuff.c:6528 sock_alloc_send_pskb+0x91a/0xa60 net/core/sock.c:2815 sock_alloc_send_skb include/net/sock.h:1778 [inline] queue_oob+0x108/0x680 net/unix/af_unix.c:2198 unix_stream_sendmsg+0xd24/0xf80 net/unix/af_unix.c:2351 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg+0x221/0x270 net/socket.c:745 ____sys_sendmsg+0x525/0x7d0 net/socket.c:2597 ___sys_sendmsg net/socket.c:2651 [inline] __sys_sendmsg+0x2b0/0x3a0 net/socket.c:2680 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 Freed by task 5235: kasan_save_stack mm/kasan/common.c:47 ---truncated---

In the Linux kernel, the following vulnerability has been resolved: net/mlx5: Always stop health timer during driver removal Currently, if teardown_hca fails to execute during driver removal, mlx5 does not stop the health timer. Afterwards, mlx5 continue with driver teardown. This may lead to a UAF bug, which results in page fault Oops[1], since the health timer invokes after resources were freed. Hence, stop the health monitor even if teardown_hca fails. [1] mlx5_core 0000:18:00.0: E-Switch: Unload vfs: mode(LEGACY), nvfs(0), necvfs(0), active vports(0) mlx5_core 0000:18:00.0: E-Switch: Disable: mode(LEGACY), nvfs(0), necvfs(0), active vports(0) mlx5_core 0000:18:00.0: E-Switch: Disable: mode(LEGACY), nvfs(0), necvfs(0), active vports(0) mlx5_core 0000:18:00.0: E-Switch: cleanup mlx5_core 0000:18:00.0: wait_func:1155:(pid 1967079): TEARDOWN_HCA(0x103) timeout. Will cause a leak of a command resource mlx5_core 0000:18:00.0: mlx5_function_close:1288:(pid 1967079): tear_down_hca failed, skip cleanup BUG: unable to handle page fault for address: ffffa26487064230 PGD 100c00067 P4D 100c00067 PUD 100e5a067 PMD 105ed7067 PTE 0 Oops: 0000 [#1] PREEMPT SMP PTI CPU: 0 PID: 0 Comm: swapper/0 Tainted: G OE ------- --- 6.7.0-68.fc38.x86_64 #1 Hardware name: Intel Corporation S2600WFT/S2600WFT, BIOS SE5C620.86B.02.01.0013.121520200651 12/15/2020 RIP: 0010:ioread32be+0x34/0x60 RSP: 0018:ffffa26480003e58 EFLAGS: 00010292 RAX: ffffa26487064200 RBX: ffff9042d08161a0 RCX: ffff904c108222c0 RDX: 000000010bbf1b80 RSI: ffffffffc055ddb0 RDI: ffffa26487064230 RBP: ffff9042d08161a0 R08: 0000000000000022 R09: ffff904c108222e8 R10: 0000000000000004 R11: 0000000000000441 R12: ffffffffc055ddb0 R13: ffffa26487064200 R14: ffffa26480003f00 R15: ffff904c108222c0 FS: 0000000000000000(0000) GS:ffff904c10800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffa26487064230 CR3: 00000002c4420006 CR4: 00000000007706f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 PKRU: 55555554 Call Trace: <IRQ> ? __die+0x23/0x70 ? page_fault_oops+0x171/0x4e0 ? exc_page_fault+0x175/0x180 ? asm_exc_page_fault+0x26/0x30 ? __pfx_poll_health+0x10/0x10 [mlx5_core] ? __pfx_poll_health+0x10/0x10 [mlx5_core] ? ioread32be+0x34/0x60 mlx5_health_check_fatal_sensors+0x20/0x100 [mlx5_core] ? __pfx_poll_health+0x10/0x10 [mlx5_core] poll_health+0x42/0x230 [mlx5_core] ? __next_timer_interrupt+0xbc/0x110 ? __pfx_poll_health+0x10/0x10 [mlx5_core] call_timer_fn+0x21/0x130 ? __pfx_poll_health+0x10/0x10 [mlx5_core] __run_timers+0x222/0x2c0 run_timer_softirq+0x1d/0x40 __do_softirq+0xc9/0x2c8 __irq_exit_rcu+0xa6/0xc0 sysvec_apic_timer_interrupt+0x72/0x90 </IRQ> <TASK> asm_sysvec_apic_timer_interrupt+0x1a/0x20 RIP: 0010:cpuidle_enter_state+0xcc/0x440 ? cpuidle_enter_state+0xbd/0x440 cpuidle_enter+0x2d/0x40 do_idle+0x20d/0x270 cpu_startup_entry+0x2a/0x30 rest_init+0xd0/0xd0 arch_call_rest_init+0xe/0x30 start_kernel+0x709/0xa90 x86_64_start_reservations+0x18/0x30 x86_64_start_kernel+0x96/0xa0 secondary_startup_64_no_verify+0x18f/0x19b ---[ end trace 0000000000000000 ]---

In the Linux kernel, the following vulnerability has been resolved: PCI/MSI: Fix UAF in msi_capability_init KFENCE reports the following UAF: BUG: KFENCE: use-after-free read in __pci_enable_msi_range+0x2c0/0x488 Use-after-free read at 0x0000000024629571 (in kfence-#12): __pci_enable_msi_range+0x2c0/0x488 pci_alloc_irq_vectors_affinity+0xec/0x14c pci_alloc_irq_vectors+0x18/0x28 kfence-#12: 0x0000000008614900-0x00000000e06c228d, size=104, cache=kmalloc-128 allocated by task 81 on cpu 7 at 10.808142s: __kmem_cache_alloc_node+0x1f0/0x2bc kmalloc_trace+0x44/0x138 msi_alloc_desc+0x3c/0x9c msi_domain_insert_msi_desc+0x30/0x78 msi_setup_msi_desc+0x13c/0x184 __pci_enable_msi_range+0x258/0x488 pci_alloc_irq_vectors_affinity+0xec/0x14c pci_alloc_irq_vectors+0x18/0x28 freed by task 81 on cpu 7 at 10.811436s: msi_domain_free_descs+0xd4/0x10c msi_domain_free_locked.part.0+0xc0/0x1d8 msi_domain_alloc_irqs_all_locked+0xb4/0xbc pci_msi_setup_msi_irqs+0x30/0x4c __pci_enable_msi_range+0x2a8/0x488 pci_alloc_irq_vectors_affinity+0xec/0x14c pci_alloc_irq_vectors+0x18/0x28 Descriptor allocation done in: __pci_enable_msi_range msi_capability_init msi_setup_msi_desc msi_insert_msi_desc msi_domain_insert_msi_desc msi_alloc_desc ... Freed in case of failure in __msi_domain_alloc_locked() __pci_enable_msi_range msi_capability_init pci_msi_setup_msi_irqs msi_domain_alloc_irqs_all_locked msi_domain_alloc_locked __msi_domain_alloc_locked => fails msi_domain_free_locked ... That failure propagates back to pci_msi_setup_msi_irqs() in msi_capability_init() which accesses the descriptor for unmasking in the error exit path. Cure it by copying the descriptor and using the copy for the error exit path unmask operation. [ tglx: Massaged change log ]

A use-after-free flaw was found in the netfilter subsystem of the Linux kernel. If the catchall element is garbage-collected when the pipapo set is removed, the element can be deactivated twice. This can cause a use-after-free issue on an NFT_CHAIN object or NFT_OBJECT object, allowing a local unprivileged user with CAP_NET_ADMIN capability to escalate their privileges on the system.

In the Linux kernel, the following vulnerability has been resolved: usb: typec: tcpm: fix use-after-free case in tcpm_register_source_caps There could be a potential use-after-free case in tcpm_register_source_caps(). This could happen when: * new (say invalid) source caps are advertised * the existing source caps are unregistered * tcpm_register_source_caps() returns with an error as usb_power_delivery_register_capabilities() fails This causes port->partner_source_caps to hold on to the now freed source caps. Reset port->partner_source_caps value to NULL after unregistering existing source caps.

A use-after-free flaw was found in the Linux Kernel. When a disk is removed, bdi_unregister is called to stop further write-back and waits for associated delayed work to complete. However, wb_inode_writeback_end() may schedule bandwidth estimation work after this has completed, which can result in the timer attempting to access the recently freed bdi_writeback.

A use-after-free flaw was found in the Linux kernel’s pipes functionality in how a user performs manipulations with the pipe post_one_notification() after free_pipe_info() that is already called. This flaw allows a local user to crash or potentially escalate their privileges on the system.

In the Linux kernel, the following vulnerability has been resolved: cachefiles: fix slab-use-after-free in fscache_withdraw_volume() We got the following issue in our fault injection stress test: ================================================================== BUG: KASAN: slab-use-after-free in fscache_withdraw_volume+0x2e1/0x370 Read of size 4 at addr ffff88810680be08 by task ondemand-04-dae/5798 CPU: 0 PID: 5798 Comm: ondemand-04-dae Not tainted 6.8.0-dirty #565 Call Trace: kasan_check_range+0xf6/0x1b0 fscache_withdraw_volume+0x2e1/0x370 cachefiles_withdraw_volume+0x31/0x50 cachefiles_withdraw_cache+0x3ad/0x900 cachefiles_put_unbind_pincount+0x1f6/0x250 cachefiles_daemon_release+0x13b/0x290 __fput+0x204/0xa00 task_work_run+0x139/0x230 Allocated by task 5820: __kmalloc+0x1df/0x4b0 fscache_alloc_volume+0x70/0x600 __fscache_acquire_volume+0x1c/0x610 erofs_fscache_register_volume+0x96/0x1a0 erofs_fscache_register_fs+0x49a/0x690 erofs_fc_fill_super+0x6c0/0xcc0 vfs_get_super+0xa9/0x140 vfs_get_tree+0x8e/0x300 do_new_mount+0x28c/0x580 [...] Freed by task 5820: kfree+0xf1/0x2c0 fscache_put_volume.part.0+0x5cb/0x9e0 erofs_fscache_unregister_fs+0x157/0x1b0 erofs_kill_sb+0xd9/0x1c0 deactivate_locked_super+0xa3/0x100 vfs_get_super+0x105/0x140 vfs_get_tree+0x8e/0x300 do_new_mount+0x28c/0x580 [...] ================================================================== Following is the process that triggers the issue: mount failed | daemon exit ------------------------------------------------------------ deactivate_locked_super cachefiles_daemon_release erofs_kill_sb erofs_fscache_unregister_fs fscache_relinquish_volume __fscache_relinquish_volume fscache_put_volume(fscache_volume, fscache_volume_put_relinquish) zero = __refcount_dec_and_test(&fscache_volume->ref, &ref); cachefiles_put_unbind_pincount cachefiles_daemon_unbind cachefiles_withdraw_cache cachefiles_withdraw_volumes list_del_init(&volume->cache_link) fscache_free_volume(fscache_volume) cache->ops->free_volume cachefiles_free_volume list_del_init(&cachefiles_volume->cache_link); kfree(fscache_volume) cachefiles_withdraw_volume fscache_withdraw_volume fscache_volume->n_accesses // fscache_volume UAF !!! The fscache_volume in cache->volumes must not have been freed yet, but its reference count may be 0. So use the new fscache_try_get_volume() helper function try to get its reference count. If the reference count of fscache_volume is 0, fscache_put_volume() is freeing it, so wait for it to be removed from cache->volumes. If its reference count is not 0, call cachefiles_withdraw_volume() with reference count protection to avoid the above issue.

A use-after-free flaw was found in the Linux kernel’s io_uring subsystem in the way a user sets up a ring with IORING_SETUP_IOPOLL with more than one task completing submissions on this ring. This flaw allows a local user to crash or escalate their privileges on the system.

Use-after-free vulnerability in fs/crypto/ in the Linux kernel before 4.10.7 allows local users to cause a denial of service (NULL pointer dereference) or possibly gain privileges by revoking keyring keys being used for ext4, f2fs, or ubifs encryption, causing cryptographic transform objects to be freed prematurely.

In the Linux kernel, the following vulnerability has been resolved: net: bonding: fix use-after-free after 802.3ad slave unbind commit 0622cab0341c ("bonding: fix 802.3ad aggregator reselection"), resolve case, when there is several aggregation groups in the same bond. bond_3ad_unbind_slave will invalidate (clear) aggregator when __agg_active_ports return zero. So, ad_clear_agg can be executed even, when num_of_ports!=0. Than bond_3ad_unbind_slave can be executed again for, previously cleared aggregator. NOTE: at this time bond_3ad_unbind_slave will not update slave ports list, because lag_ports==NULL. So, here we got slave ports, pointing to freed aggregator memory. Fix with checking actual number of ports in group (as was before commit 0622cab0341c ("bonding: fix 802.3ad aggregator reselection") ), before ad_clear_agg(). The KASAN logs are as follows: [ 767.617392] ================================================================== [ 767.630776] BUG: KASAN: use-after-free in bond_3ad_state_machine_handler+0x13dc/0x1470 [ 767.638764] Read of size 2 at addr ffff00011ba9d430 by task kworker/u8:7/767 [ 767.647361] CPU: 3 PID: 767 Comm: kworker/u8:7 Tainted: G O 5.15.11 #15 [ 767.655329] Hardware name: DNI AmazonGo1 A7040 board (DT) [ 767.660760] Workqueue: lacp_1 bond_3ad_state_machine_handler [ 767.666468] Call trace: [ 767.668930] dump_backtrace+0x0/0x2d0 [ 767.672625] show_stack+0x24/0x30 [ 767.675965] dump_stack_lvl+0x68/0x84 [ 767.679659] print_address_description.constprop.0+0x74/0x2b8 [ 767.685451] kasan_report+0x1f0/0x260 [ 767.689148] __asan_load2+0x94/0xd0 [ 767.692667] bond_3ad_state_machine_handler+0x13dc/0x1470

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: Fix use after free in hci_send_acl This fixes the following trace caused by receiving HCI_EV_DISCONN_PHY_LINK_COMPLETE which does call hci_conn_del without first checking if conn->type is in fact AMP_LINK and in case it is do properly cleanup upper layers with hci_disconn_cfm: ================================================================== BUG: KASAN: use-after-free in hci_send_acl+0xaba/0xc50 Read of size 8 at addr ffff88800e404818 by task bluetoothd/142 CPU: 0 PID: 142 Comm: bluetoothd Not tainted 5.17.0-rc5-00006-gda4022eeac1a #7 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014 Call Trace: <TASK> dump_stack_lvl+0x45/0x59 print_address_description.constprop.0+0x1f/0x150 kasan_report.cold+0x7f/0x11b hci_send_acl+0xaba/0xc50 l2cap_do_send+0x23f/0x3d0 l2cap_chan_send+0xc06/0x2cc0 l2cap_sock_sendmsg+0x201/0x2b0 sock_sendmsg+0xdc/0x110 sock_write_iter+0x20f/0x370 do_iter_readv_writev+0x343/0x690 do_iter_write+0x132/0x640 vfs_writev+0x198/0x570 do_writev+0x202/0x280 do_syscall_64+0x38/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xae RSP: 002b:00007ffce8a099b8 EFLAGS: 00000246 ORIG_RAX: 0000000000000014 Code: 0f 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b8 0f 1f 00 f3 0f 1e fa 64 8b 04 25 18 00 00 00 85 c0 75 10 b8 14 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 51 c3 48 83 ec 28 89 54 24 1c 48 89 74 24 10 RDX: 0000000000000001 RSI: 00007ffce8a099e0 RDI: 0000000000000015 RAX: ffffffffffffffda RBX: 00007ffce8a099e0 RCX: 00007f788fc3cf77 R10: 00007ffce8af7080 R11: 0000000000000246 R12: 000055e4ccf75580 RBP: 0000000000000015 R08: 0000000000000002 R09: 0000000000000001 </TASK> R13: 000055e4ccf754a0 R14: 000055e4ccf75cd0 R15: 000055e4ccf4a6b0 Allocated by task 45: kasan_save_stack+0x1e/0x40 __kasan_kmalloc+0x81/0xa0 hci_chan_create+0x9a/0x2f0 l2cap_conn_add.part.0+0x1a/0xdc0 l2cap_connect_cfm+0x236/0x1000 le_conn_complete_evt+0x15a7/0x1db0 hci_le_conn_complete_evt+0x226/0x2c0 hci_le_meta_evt+0x247/0x450 hci_event_packet+0x61b/0xe90 hci_rx_work+0x4d5/0xc50 process_one_work+0x8fb/0x15a0 worker_thread+0x576/0x1240 kthread+0x29d/0x340 ret_from_fork+0x1f/0x30 Freed by task 45: kasan_save_stack+0x1e/0x40 kasan_set_track+0x21/0x30 kasan_set_free_info+0x20/0x30 __kasan_slab_free+0xfb/0x130 kfree+0xac/0x350 hci_conn_cleanup+0x101/0x6a0 hci_conn_del+0x27e/0x6c0 hci_disconn_phylink_complete_evt+0xe0/0x120 hci_event_packet+0x812/0xe90 hci_rx_work+0x4d5/0xc50 process_one_work+0x8fb/0x15a0 worker_thread+0x576/0x1240 kthread+0x29d/0x340 ret_from_fork+0x1f/0x30 The buggy address belongs to the object at ffff88800c0f0500 The buggy address is located 24 bytes inside of which belongs to the cache kmalloc-128 of size 128 The buggy address belongs to the page: 128-byte region [ffff88800c0f0500, ffff88800c0f0580) flags: 0x100000000000200(slab|node=0|zone=1) page:00000000fe45cd86 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0xc0f0 raw: 0000000000000000 0000000080100010 00000001ffffffff 0000000000000000 raw: 0100000000000200 ffffea00003a2c80 dead000000000004 ffff8880078418c0 page dumped because: kasan: bad access detected ffff88800c0f0400: 00 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc Memory state around the buggy address: >ffff88800c0f0500: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88800c0f0480: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88800c0f0580: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ---truncated---

A flaw was found in the Linux kernel’s implementation of IO-URING. This flaw allows an attacker with local executable permission to create a string of requests that can cause a use-after-free flaw within the kernel. This issue leads to memory corruption and possible privilege escalation.

In the Linux kernel, the following vulnerability has been resolved: net: fix use-after-free in tw_timer_handler A real world panic issue was found as follow in Linux 5.4. BUG: unable to handle page fault for address: ffffde49a863de28 PGD 7e6fe62067 P4D 7e6fe62067 PUD 7e6fe63067 PMD f51e064067 PTE 0 RIP: 0010:tw_timer_handler+0x20/0x40 Call Trace: <IRQ> call_timer_fn+0x2b/0x120 run_timer_softirq+0x1ef/0x450 __do_softirq+0x10d/0x2b8 irq_exit+0xc7/0xd0 smp_apic_timer_interrupt+0x68/0x120 apic_timer_interrupt+0xf/0x20 This issue was also reported since 2017 in the thread [1], unfortunately, the issue was still can be reproduced after fixing DCCP. The ipv4_mib_exit_net is called before tcp_sk_exit_batch when a net namespace is destroyed since tcp_sk_ops is registered befrore ipv4_mib_ops, which means tcp_sk_ops is in the front of ipv4_mib_ops in the list of pernet_list. There will be a use-after-free on net->mib.net_statistics in tw_timer_handler after ipv4_mib_exit_net if there are some inflight time-wait timers. This bug is not introduced by commit f2bf415cfed7 ("mib: add net to NET_ADD_STATS_BH") since the net_statistics is a global variable instead of dynamic allocation and freeing. Actually, commit 61a7e26028b9 ("mib: put net statistics on struct net") introduces the bug since it put net statistics on struct net and free it when net namespace is destroyed. Moving init_ipv4_mibs() to the front of tcp_init() to fix this bug and replace pr_crit() with panic() since continuing is meaningless when init_ipv4_mibs() fails. [1] https://groups.google.com/g/syzkaller/c/p1tn-_Kc6l4/m/smuL_FMAAgAJ?pli=1

In the Linux kernel, the following vulnerability has been resolved: bus: mhi: core: Fix invalid error returning in mhi_queue mhi_queue returns an error when the doorbell is not accessible in the current state. This can happen when the device is in non M0 state, like M3, and needs to be waken-up prior ringing the DB. This case is managed earlier by triggering an asynchronous M3 exit via controller resume/suspend callbacks, that in turn will cause M0 transition and DB update. So, since it's not an error but just delaying of doorbell update, there is no reason to return an error. This also fixes a use after free error for skb case, indeed a caller queuing skb will try to free the skb if the queueing fails, but in that case queueing has been done.

In the Linux kernel, the following vulnerability has been resolved: pid: take a reference when initializing `cad_pid` During boot, kernel_init_freeable() initializes `cad_pid` to the init task's struct pid. Later on, we may change `cad_pid` via a sysctl, and when this happens proc_do_cad_pid() will increment the refcount on the new pid via get_pid(), and will decrement the refcount on the old pid via put_pid(). As we never called get_pid() when we initialized `cad_pid`, we decrement a reference we never incremented, can therefore free the init task's struct pid early. As there can be dangling references to the struct pid, we can later encounter a use-after-free (e.g. when delivering signals). This was spotted when fuzzing v5.13-rc3 with Syzkaller, but seems to have been around since the conversion of `cad_pid` to struct pid in commit 9ec52099e4b8 ("[PATCH] replace cad_pid by a struct pid") from the pre-KASAN stone age of v2.6.19. Fix this by getting a reference to the init task's struct pid when we assign it to `cad_pid`. Full KASAN splat below. ================================================================== BUG: KASAN: use-after-free in ns_of_pid include/linux/pid.h:153 [inline] BUG: KASAN: use-after-free in task_active_pid_ns+0xc0/0xc8 kernel/pid.c:509 Read of size 4 at addr ffff23794dda0004 by task syz-executor.0/273 CPU: 1 PID: 273 Comm: syz-executor.0 Not tainted 5.12.0-00001-g9aef892b2d15 #1 Hardware name: linux,dummy-virt (DT) Call trace: ns_of_pid include/linux/pid.h:153 [inline] task_active_pid_ns+0xc0/0xc8 kernel/pid.c:509 do_notify_parent+0x308/0xe60 kernel/signal.c:1950 exit_notify kernel/exit.c:682 [inline] do_exit+0x2334/0x2bd0 kernel/exit.c:845 do_group_exit+0x108/0x2c8 kernel/exit.c:922 get_signal+0x4e4/0x2a88 kernel/signal.c:2781 do_signal arch/arm64/kernel/signal.c:882 [inline] do_notify_resume+0x300/0x970 arch/arm64/kernel/signal.c:936 work_pending+0xc/0x2dc Allocated by task 0: slab_post_alloc_hook+0x50/0x5c0 mm/slab.h:516 slab_alloc_node mm/slub.c:2907 [inline] slab_alloc mm/slub.c:2915 [inline] kmem_cache_alloc+0x1f4/0x4c0 mm/slub.c:2920 alloc_pid+0xdc/0xc00 kernel/pid.c:180 copy_process+0x2794/0x5e18 kernel/fork.c:2129 kernel_clone+0x194/0x13c8 kernel/fork.c:2500 kernel_thread+0xd4/0x110 kernel/fork.c:2552 rest_init+0x44/0x4a0 init/main.c:687 arch_call_rest_init+0x1c/0x28 start_kernel+0x520/0x554 init/main.c:1064 0x0 Freed by task 270: slab_free_hook mm/slub.c:1562 [inline] slab_free_freelist_hook+0x98/0x260 mm/slub.c:1600 slab_free mm/slub.c:3161 [inline] kmem_cache_free+0x224/0x8e0 mm/slub.c:3177 put_pid.part.4+0xe0/0x1a8 kernel/pid.c:114 put_pid+0x30/0x48 kernel/pid.c:109 proc_do_cad_pid+0x190/0x1b0 kernel/sysctl.c:1401 proc_sys_call_handler+0x338/0x4b0 fs/proc/proc_sysctl.c:591 proc_sys_write+0x34/0x48 fs/proc/proc_sysctl.c:617 call_write_iter include/linux/fs.h:1977 [inline] new_sync_write+0x3ac/0x510 fs/read_write.c:518 vfs_write fs/read_write.c:605 [inline] vfs_write+0x9c4/0x1018 fs/read_write.c:585 ksys_write+0x124/0x240 fs/read_write.c:658 __do_sys_write fs/read_write.c:670 [inline] __se_sys_write fs/read_write.c:667 [inline] __arm64_sys_write+0x78/0xb0 fs/read_write.c:667 __invoke_syscall arch/arm64/kernel/syscall.c:37 [inline] invoke_syscall arch/arm64/kernel/syscall.c:49 [inline] el0_svc_common.constprop.1+0x16c/0x388 arch/arm64/kernel/syscall.c:129 do_el0_svc+0xf8/0x150 arch/arm64/kernel/syscall.c:168 el0_svc+0x28/0x38 arch/arm64/kernel/entry-common.c:416 el0_sync_handler+0x134/0x180 arch/arm64/kernel/entry-common.c:432 el0_sync+0x154/0x180 arch/arm64/kernel/entry.S:701 The buggy address belongs to the object at ffff23794dda0000 which belongs to the cache pid of size 224 The buggy address is located 4 bytes inside of 224-byte region [ff ---truncated---

In the Linux kernel, the following vulnerability has been resolved: media: davinci: vpif: fix use-after-free on driver unbind The driver allocates and registers two platform device structures during probe, but the devices were never deregistered on driver unbind. This results in a use-after-free on driver unbind as the device structures were allocated using devres and would be freed by driver core when remove() returns. Fix this by adding the missing deregistration calls to the remove() callback and failing probe on registration errors. Note that the platform device structures must be freed using a proper release callback to avoid leaking associated resources like device names.

In the Linux kernel, the following vulnerability has been resolved: ubi: Fix race condition between ctrl_cdev_ioctl and ubi_cdev_ioctl Hulk Robot reported a KASAN report about use-after-free: ================================================================== BUG: KASAN: use-after-free in __list_del_entry_valid+0x13d/0x160 Read of size 8 at addr ffff888035e37d98 by task ubiattach/1385 [...] Call Trace: klist_dec_and_del+0xa7/0x4a0 klist_put+0xc7/0x1a0 device_del+0x4d4/0xed0 cdev_device_del+0x1a/0x80 ubi_attach_mtd_dev+0x2951/0x34b0 [ubi] ctrl_cdev_ioctl+0x286/0x2f0 [ubi] Allocated by task 1414: device_add+0x60a/0x18b0 cdev_device_add+0x103/0x170 ubi_create_volume+0x1118/0x1a10 [ubi] ubi_cdev_ioctl+0xb7f/0x1ba0 [ubi] Freed by task 1385: cdev_device_del+0x1a/0x80 ubi_remove_volume+0x438/0x6c0 [ubi] ubi_cdev_ioctl+0xbf4/0x1ba0 [ubi] [...] ================================================================== The lock held by ctrl_cdev_ioctl is ubi_devices_mutex, but the lock held by ubi_cdev_ioctl is ubi->device_mutex. Therefore, the two locks can be concurrent. ctrl_cdev_ioctl contains two operations: ubi_attach and ubi_detach. ubi_detach is bug-free because it uses reference counting to prevent concurrency. However, uif_init and uif_close in ubi_attach may race with ubi_cdev_ioctl. uif_init will race with ubi_cdev_ioctl as in the following stack. cpu1 cpu2 cpu3 _______________________|________________________|______________________ ctrl_cdev_ioctl ubi_attach_mtd_dev uif_init ubi_cdev_ioctl ubi_create_volume cdev_device_add ubi_add_volume // sysfs exist kill_volumes ubi_cdev_ioctl ubi_remove_volume cdev_device_del // first free ubi_free_volume cdev_del // double free cdev_device_del And uif_close will race with ubi_cdev_ioctl as in the following stack. cpu1 cpu2 cpu3 _______________________|________________________|______________________ ctrl_cdev_ioctl ubi_attach_mtd_dev uif_init ubi_cdev_ioctl ubi_create_volume cdev_device_add ubi_debugfs_init_dev //error goto out_uif; uif_close kill_volumes ubi_cdev_ioctl ubi_remove_volume cdev_device_del // first free ubi_free_volume // double free The cause of this problem is that commit 714fb87e8bc0 make device "available" before it becomes accessible via sysfs. Therefore, we roll back the modification. We will fix the race condition between ubi device creation and udev by removing ubi_get_device in vol_attribute_show and dev_attribute_show.This avoids accessing uninitialized ubi_devices[ubi_num]. ubi_get_device is used to prevent devices from being deleted during sysfs execution. However, now kernfs ensures that devices will not be deleted before all reference counting are released. The key process is shown in the following stack. device_del device_remove_attrs device_remove_groups sysfs_remove_groups sysfs_remove_group remove_files kernfs_remove_by_name kernfs_remove_by_name_ns __kernfs_remove kernfs_drain

A use-after-free vulnerability in the Linux kernel's netfilter: nf_tables component can be exploited to achieve local privilege escalation. The function nft_pipapo_walk did not skip inactive elements during set walk which could lead double deactivations of PIPAPO (Pile Packet Policies) elements, leading to use-after-free. We recommend upgrading past commit 317eb9685095678f2c9f5a8189de698c5354316a.

In the Linux kernel, the following vulnerability has been resolved: RDMA/rtrs-clt: destroy sysfs after removing session from active list A session can be removed dynamically by sysfs interface "remove_path" that eventually calls rtrs_clt_remove_path_from_sysfs function. The current rtrs_clt_remove_path_from_sysfs first removes the sysfs interfaces and frees sess->stats object. Second it removes the session from the active list. Therefore some functions could access non-connected session and access the freed sess->stats object even-if they check the session status before accessing the session. For instance rtrs_clt_request and get_next_path_min_inflight check the session status and try to send IO to the session. The session status could be changed when they are trying to send IO but they could not catch the change and update the statistics information in sess->stats object, and generate use-after-free problem. (see: "RDMA/rtrs-clt: Check state of the rtrs_clt_sess before reading its stats") This patch changes the rtrs_clt_remove_path_from_sysfs to remove the session from the active session list and then destroy the sysfs interfaces. Each function still should check the session status because closing or error recovery paths can change the status.

In the Linux kernel, the following vulnerability has been resolved: atm: nicstar: Fix possible use-after-free in nicstar_cleanup() This module's remove path calls del_timer(). However, that function does not wait until the timer handler finishes. This means that the timer handler may still be running after the driver's remove function has finished, which would result in a use-after-free. Fix by calling del_timer_sync(), which makes sure the timer handler has finished, and unable to re-schedule itself.

In the Linux kernel, the following vulnerability has been resolved: gfs2: Fix use-after-free in gfs2_glock_shrink_scan The GLF_LRU flag is checked under lru_lock in gfs2_glock_remove_from_lru() to remove the glock from the lru list in __gfs2_glock_put(). On the shrink scan path, the same flag is cleared under lru_lock but because of cond_resched_lock(&lru_lock) in gfs2_dispose_glock_lru(), progress on the put side can be made without deleting the glock from the lru list. Keep GLF_LRU across the race window opened by cond_resched_lock(&lru_lock) to ensure correct behavior on both sides - clear GLF_LRU after list_del under lru_lock.

In the Linux kernel, the following vulnerability has been resolved: Revert "Revert "block, bfq: honor already-setup queue merges"" A crash [1] happened to be triggered in conjunction with commit 2d52c58b9c9b ("block, bfq: honor already-setup queue merges"). The latter was then reverted by commit ebc69e897e17 ("Revert "block, bfq: honor already-setup queue merges""). Yet, the reverted commit was not the one introducing the bug. In fact, it actually triggered a UAF introduced by a different commit, and now fixed by commit d29bd41428cf ("block, bfq: reset last_bfqq_created on group change"). So, there is no point in keeping commit 2d52c58b9c9b ("block, bfq: honor already-setup queue merges") out. This commit restores it. [1] https://bugzilla.kernel.org/show_bug.cgi?id=214503

In the Linux kernel, the following vulnerability has been resolved: can: vxcan: vxcan_xmit: fix use after free bug After calling netif_rx_ni(skb), dereferencing skb is unsafe. Especially, the canfd_frame cfd which aliases skb memory is accessed after the netif_rx_ni().

In the Linux kernel, the following vulnerability has been resolved: watchdog: Fix possible use-after-free by calling del_timer_sync() This driver's remove path calls del_timer(). However, that function does not wait until the timer handler finishes. This means that the timer handler may still be running after the driver's remove function has finished, which would result in a use-after-free. Fix by calling del_timer_sync(), which makes sure the timer handler has finished, and unable to re-schedule itself.

In the Linux kernel, the following vulnerability has been resolved: RDMA/siw: Fix a use after free in siw_alloc_mr Our code analyzer reported a UAF. In siw_alloc_mr(), it calls siw_mr_add_mem(mr,..). In the implementation of siw_mr_add_mem(), mem is assigned to mr->mem and then mem is freed via kfree(mem) if xa_alloc_cyclic() failed. Here, mr->mem still point to a freed object. After, the execution continue up to the err_out branch of siw_alloc_mr, and the freed mr->mem is used in siw_mr_drop_mem(mr). My patch moves "mr->mem = mem" behind the if (xa_alloc_cyclic(..)<0) {} section, to avoid the uaf.

In the Linux kernel, the following vulnerability has been resolved: bpf: Track subprog poke descriptors correctly and fix use-after-free Subprograms are calling map_poke_track(), but on program release there is no hook to call map_poke_untrack(). However, on program release, the aux memory (and poke descriptor table) is freed even though we still have a reference to it in the element list of the map aux data. When we run map_poke_run(), we then end up accessing free'd memory, triggering KASAN in prog_array_map_poke_run(): [...] [ 402.824689] BUG: KASAN: use-after-free in prog_array_map_poke_run+0xc2/0x34e [ 402.824698] Read of size 4 at addr ffff8881905a7940 by task hubble-fgs/4337 [ 402.824705] CPU: 1 PID: 4337 Comm: hubble-fgs Tainted: G I 5.12.0+ #399 [ 402.824715] Call Trace: [ 402.824719] dump_stack+0x93/0xc2 [ 402.824727] print_address_description.constprop.0+0x1a/0x140 [ 402.824736] ? prog_array_map_poke_run+0xc2/0x34e [ 402.824740] ? prog_array_map_poke_run+0xc2/0x34e [ 402.824744] kasan_report.cold+0x7c/0xd8 [ 402.824752] ? prog_array_map_poke_run+0xc2/0x34e [ 402.824757] prog_array_map_poke_run+0xc2/0x34e [ 402.824765] bpf_fd_array_map_update_elem+0x124/0x1a0 [...] The elements concerned are walked as follows: for (i = 0; i < elem->aux->size_poke_tab; i++) { poke = &elem->aux->poke_tab[i]; [...] The access to size_poke_tab is a 4 byte read, verified by checking offsets in the KASAN dump: [ 402.825004] The buggy address belongs to the object at ffff8881905a7800 which belongs to the cache kmalloc-1k of size 1024 [ 402.825008] The buggy address is located 320 bytes inside of 1024-byte region [ffff8881905a7800, ffff8881905a7c00) The pahole output of bpf_prog_aux: struct bpf_prog_aux { [...] /* --- cacheline 5 boundary (320 bytes) --- */ u32 size_poke_tab; /* 320 4 */ [...] In general, subprograms do not necessarily manage their own data structures. For example, BTF func_info and linfo are just pointers to the main program structure. This allows reference counting and cleanup to be done on the latter which simplifies their management a bit. The aux->poke_tab struct, however, did not follow this logic. The initial proposed fix for this use-after-free bug further embedded poke data tracking into the subprogram with proper reference counting. However, Daniel and Alexei questioned why we were treating these objects special; I agree, its unnecessary. The fix here removes the per subprogram poke table allocation and map tracking and instead simply points the aux->poke_tab pointer at the main programs poke table. This way, map tracking is simplified to the main program and we do not need to manage them per subprogram. This also means, bpf_prog_free_deferred(), which unwinds the program reference counting and kfrees objects, needs to ensure that we don't try to double free the poke_tab when free'ing the subprog structures. This is easily solved by NULL'ing the poke_tab pointer. The second detail is to ensure that per subprogram JIT logic only does fixups on poke_tab[] entries it owns. To do this, we add a pointer in the poke structure to point at the subprogram value so JITs can easily check while walking the poke_tab structure if the current entry belongs to the current program. The aux pointer is stable and therefore suitable for such comparison. On the jit_subprogs() error path, we omit cleaning up the poke->aux field because these are only ever referenced from the JIT side, but on error we will never make it to the JIT, so its fine to leave them dangling. Removing these pointers would complicate the error path for no reason. However, we do need to untrack all poke descriptors from the main program as otherwise they could race with the freeing of JIT memory from the subprograms. Lastly, a748c6975dea3 ("bpf: propagate poke des ---truncated---

In the Linux kernel, the following vulnerability has been resolved: igb: Fix use-after-free error during reset Cleans the next descriptor to watch (next_to_watch) when cleaning the TX ring. Failure to do so can cause invalid memory accesses. If igb_poll() runs while the controller is reset this can lead to the driver try to free a skb that was already freed. (The crash is harder to reproduce with the igb driver, but the same potential problem exists as the code is identical to igc)

In the Linux kernel, the following vulnerability has been resolved: mac80211: fix use-after-free in CCMP/GCMP RX When PN checking is done in mac80211, for fragmentation we need to copy the PN to the RX struct so we can later use it to do a comparison, since commit bf30ca922a0c ("mac80211: check defrag PN against current frame"). Unfortunately, in that commit I used the 'hdr' variable without it being necessarily valid, so use-after-free could occur if it was necessary to reallocate (parts of) the frame. Fix this by reloading the variable after the code that results in the reallocations, if any. This fixes https://bugzilla.kernel.org/show_bug.cgi?id=214401.

In the Linux kernel, the following vulnerability has been resolved: bus: mhi: pci_generic: Fix possible use-after-free in mhi_pci_remove() This driver's remove path calls del_timer(). However, that function does not wait until the timer handler finishes. This means that the timer handler may still be running after the driver's remove function has finished, which would result in a use-after-free. Fix by calling del_timer_sync(), which makes sure the timer handler has finished, and unable to re-schedule itself.

In the Linux kernel, the following vulnerability has been resolved: ath10k: Fix a use after free in ath10k_htc_send_bundle In ath10k_htc_send_bundle, the bundle_skb could be freed by dev_kfree_skb_any(bundle_skb). But the bundle_skb is used later by bundle_skb->len. As skb_len = bundle_skb->len, my patch replaces bundle_skb->len to skb_len after the bundle_skb was freed.

In the Linux kernel, the following vulnerability has been resolved: nfsd: fix use-after-free due to delegation race A delegation break could arrive as soon as we've called vfs_setlease. A delegation break runs a callback which immediately (in nfsd4_cb_recall_prepare) adds the delegation to del_recall_lru. If we then exit nfs4_set_delegation without hashing the delegation, it will be freed as soon as the callback is done with it, without ever being removed from del_recall_lru. Symptoms show up later as use-after-free or list corruption warnings, usually in the laundromat thread. I suspect aba2072f4523 "nfsd: grant read delegations to clients holding writes" made this bug easier to hit, but I looked as far back as v3.0 and it looks to me it already had the same problem. So I'm not sure where the bug was introduced; it may have been there from the beginning.

In the Linux kernel, the following vulnerability has been resolved: net: ti: fix UAF in tlan_remove_one priv is netdev private data and it cannot be used after free_netdev() call. Using priv after free_netdev() can cause UAF bug. Fix it by moving free_netdev() at the end of the function.

In the Linux kernel, the following vulnerability has been resolved: staging: rtl8192e: Fix use after free in _rtl92e_pci_disconnect() The free_rtllib() function frees the "dev" pointer so there is use after free on the next line. Re-arrange things to avoid that.

A use-after-free vulnerability in the Linux kernel's ipv4: igmp component can be exploited to achieve local privilege escalation. A race condition can be exploited to cause a timer be mistakenly registered on a RCU read locked object which is freed by another thread. We recommend upgrading past commit e2b706c691905fe78468c361aaabc719d0a496f1.

In the Linux kernel, the following vulnerability has been resolved: aio: fix use-after-free due to missing POLLFREE handling signalfd_poll() and binder_poll() are special in that they use a waitqueue whose lifetime is the current task, rather than the struct file as is normally the case. This is okay for blocking polls, since a blocking poll occurs within one task; however, non-blocking polls require another solution. This solution is for the queue to be cleared before it is freed, by sending a POLLFREE notification to all waiters. Unfortunately, only eventpoll handles POLLFREE. A second type of non-blocking poll, aio poll, was added in kernel v4.18, and it doesn't handle POLLFREE. This allows a use-after-free to occur if a signalfd or binder fd is polled with aio poll, and the waitqueue gets freed. Fix this by making aio poll handle POLLFREE. A patch by Ramji Jiyani <ramjiyani@google.com> (https://lore.kernel.org/r/20211027011834.2497484-1-ramjiyani@google.com) tried to do this by making aio_poll_wake() always complete the request inline if POLLFREE is seen. However, that solution had two bugs. First, it introduced a deadlock, as it unconditionally locked the aio context while holding the waitqueue lock, which inverts the normal locking order. Second, it didn't consider that POLLFREE notifications are missed while the request has been temporarily de-queued. The second problem was solved by my previous patch. This patch then properly fixes the use-after-free by handling POLLFREE in a deadlock-free way. It does this by taking advantage of the fact that freeing of the waitqueue is RCU-delayed, similar to what eventpoll does.

In the Linux kernel, the following vulnerability has been resolved: cachefiles: fix slab-use-after-free in cachefiles_ondemand_daemon_read() We got the following issue in a fuzz test of randomly issuing the restore command: ================================================================== BUG: KASAN: slab-use-after-free in cachefiles_ondemand_daemon_read+0xb41/0xb60 Read of size 8 at addr ffff888122e84088 by task ondemand-04-dae/963 CPU: 13 PID: 963 Comm: ondemand-04-dae Not tainted 6.8.0-dirty #564 Call Trace: kasan_report+0x93/0xc0 cachefiles_ondemand_daemon_read+0xb41/0xb60 vfs_read+0x169/0xb50 ksys_read+0xf5/0x1e0 Allocated by task 116: kmem_cache_alloc+0x140/0x3a0 cachefiles_lookup_cookie+0x140/0xcd0 fscache_cookie_state_machine+0x43c/0x1230 [...] Freed by task 792: kmem_cache_free+0xfe/0x390 cachefiles_put_object+0x241/0x480 fscache_cookie_state_machine+0x5c8/0x1230 [...] ================================================================== Following is the process that triggers the issue: mount | daemon_thread1 | daemon_thread2 ------------------------------------------------------------ cachefiles_withdraw_cookie cachefiles_ondemand_clean_object(object) cachefiles_ondemand_send_req REQ_A = kzalloc(sizeof(*req) + data_len) wait_for_completion(&REQ_A->done) cachefiles_daemon_read cachefiles_ondemand_daemon_read REQ_A = cachefiles_ondemand_select_req msg->object_id = req->object->ondemand->ondemand_id ------ restore ------ cachefiles_ondemand_restore xas_for_each(&xas, req, ULONG_MAX) xas_set_mark(&xas, CACHEFILES_REQ_NEW) cachefiles_daemon_read cachefiles_ondemand_daemon_read REQ_A = cachefiles_ondemand_select_req copy_to_user(_buffer, msg, n) xa_erase(&cache->reqs, id) complete(&REQ_A->done) ------ close(fd) ------ cachefiles_ondemand_fd_release cachefiles_put_object cachefiles_put_object kmem_cache_free(cachefiles_object_jar, object) REQ_A->object->ondemand->ondemand_id // object UAF !!! When we see the request within xa_lock, req->object must not have been freed yet, so grab the reference count of object before xa_unlock to avoid the above issue.

In drivers/net/ethernet/hisilicon/hns/hns_enet.c in the Linux kernel before 4.13, local users can cause a denial of service (use-after-free and BUG) or possibly have unspecified other impact by leveraging differences in skb handling between hns_nic_net_xmit_hw and hns_nic_net_xmit.

In the Linux kernel, the following vulnerability has been resolved: smb: client: fix potential UAF in smb2_is_valid_lease_break() Skip sessions that are being teared down (status == SES_EXITING) to avoid UAF.

In the Linux kernel, the following vulnerability has been resolved: HSI: ssi_protocol: Fix use after free vulnerability in ssi_protocol Driver Due to Race Condition In the ssi_protocol_probe() function, &ssi->work is bound with ssip_xmit_work(), In ssip_pn_setup(), the ssip_pn_xmit() function within the ssip_pn_ops structure is capable of starting the work. If we remove the module which will call ssi_protocol_remove() to make a cleanup, it will free ssi through kfree(ssi), while the work mentioned above will be used. The sequence of operations that may lead to a UAF bug is as follows: CPU0 CPU1 | ssip_xmit_work ssi_protocol_remove | kfree(ssi); | | struct hsi_client *cl = ssi->cl; | // use ssi Fix it by ensuring that the work is canceled before proceeding with the cleanup in ssi_protocol_remove().

The mq_notify function in the Linux kernel through 4.11.9 does not set the sock pointer to NULL upon entry into the retry logic. During a user-space close of a Netlink socket, it allows attackers to cause a denial of service (use-after-free) or possibly have unspecified other impact.

In the Linux kernel, the following vulnerability has been resolved: IB/mlx5: Fix init stage error handling to avoid double free of same QP and UAF In the unlikely event that workqueue allocation fails and returns NULL in mlx5_mkey_cache_init(), delete the call to mlx5r_umr_resource_cleanup() (which frees the QP) in mlx5_ib_stage_post_ib_reg_umr_init(). This will avoid attempted double free of the same QP when __mlx5_ib_add() does its cleanup. Resolves a splat: Syzkaller reported a UAF in ib_destroy_qp_user workqueue: Failed to create a rescuer kthread for wq "mkey_cache": -EINTR infiniband mlx5_0: mlx5_mkey_cache_init:981:(pid 1642): failed to create work queue infiniband mlx5_0: mlx5_ib_stage_post_ib_reg_umr_init:4075:(pid 1642): mr cache init failed -12 ================================================================== BUG: KASAN: slab-use-after-free in ib_destroy_qp_user (drivers/infiniband/core/verbs.c:2073) Read of size 8 at addr ffff88810da310a8 by task repro_upstream/1642 Call Trace: <TASK> kasan_report (mm/kasan/report.c:590) ib_destroy_qp_user (drivers/infiniband/core/verbs.c:2073) mlx5r_umr_resource_cleanup (drivers/infiniband/hw/mlx5/umr.c:198) __mlx5_ib_add (drivers/infiniband/hw/mlx5/main.c:4178) mlx5r_probe (drivers/infiniband/hw/mlx5/main.c:4402) ... </TASK> Allocated by task 1642: __kmalloc (./include/linux/kasan.h:198 mm/slab_common.c:1026 mm/slab_common.c:1039) create_qp (./include/linux/slab.h:603 ./include/linux/slab.h:720 ./include/rdma/ib_verbs.h:2795 drivers/infiniband/core/verbs.c:1209) ib_create_qp_kernel (drivers/infiniband/core/verbs.c:1347) mlx5r_umr_resource_init (drivers/infiniband/hw/mlx5/umr.c:164) mlx5_ib_stage_post_ib_reg_umr_init (drivers/infiniband/hw/mlx5/main.c:4070) __mlx5_ib_add (drivers/infiniband/hw/mlx5/main.c:4168) mlx5r_probe (drivers/infiniband/hw/mlx5/main.c:4402) ... Freed by task 1642: __kmem_cache_free (mm/slub.c:1826 mm/slub.c:3809 mm/slub.c:3822) ib_destroy_qp_user (drivers/infiniband/core/verbs.c:2112) mlx5r_umr_resource_cleanup (drivers/infiniband/hw/mlx5/umr.c:198) mlx5_ib_stage_post_ib_reg_umr_init (drivers/infiniband/hw/mlx5/main.c:4076 drivers/infiniband/hw/mlx5/main.c:4065) __mlx5_ib_add (drivers/infiniband/hw/mlx5/main.c:4168) mlx5r_probe (drivers/infiniband/hw/mlx5/main.c:4402) ...

In the Linux kernel, the following vulnerability has been resolved: wifi: wilc1000: prevent use-after-free on vif when cleaning up all interfaces wilc_netdev_cleanup currently triggers a KASAN warning, which can be observed on interface registration error path, or simply by removing the module/unbinding device from driver: echo spi0.1 > /sys/bus/spi/drivers/wilc1000_spi/unbind ================================================================== BUG: KASAN: slab-use-after-free in wilc_netdev_cleanup+0x508/0x5cc Read of size 4 at addr c54d1ce8 by task sh/86 CPU: 0 PID: 86 Comm: sh Not tainted 6.8.0-rc1+ #117 Hardware name: Atmel SAMA5 unwind_backtrace from show_stack+0x18/0x1c show_stack from dump_stack_lvl+0x34/0x58 dump_stack_lvl from print_report+0x154/0x500 print_report from kasan_report+0xac/0xd8 kasan_report from wilc_netdev_cleanup+0x508/0x5cc wilc_netdev_cleanup from wilc_bus_remove+0xc8/0xec wilc_bus_remove from spi_remove+0x8c/0xac spi_remove from device_release_driver_internal+0x434/0x5f8 device_release_driver_internal from unbind_store+0xbc/0x108 unbind_store from kernfs_fop_write_iter+0x398/0x584 kernfs_fop_write_iter from vfs_write+0x728/0xf88 vfs_write from ksys_write+0x110/0x1e4 ksys_write from ret_fast_syscall+0x0/0x1c [...] Allocated by task 1: kasan_save_track+0x30/0x5c __kasan_kmalloc+0x8c/0x94 __kmalloc_node+0x1cc/0x3e4 kvmalloc_node+0x48/0x180 alloc_netdev_mqs+0x68/0x11dc alloc_etherdev_mqs+0x28/0x34 wilc_netdev_ifc_init+0x34/0x8ec wilc_cfg80211_init+0x690/0x910 wilc_bus_probe+0xe0/0x4a0 spi_probe+0x158/0x1b0 really_probe+0x270/0xdf4 __driver_probe_device+0x1dc/0x580 driver_probe_device+0x60/0x140 __driver_attach+0x228/0x5d4 bus_for_each_dev+0x13c/0x1a8 bus_add_driver+0x2a0/0x608 driver_register+0x24c/0x578 do_one_initcall+0x180/0x310 kernel_init_freeable+0x424/0x484 kernel_init+0x20/0x148 ret_from_fork+0x14/0x28 Freed by task 86: kasan_save_track+0x30/0x5c kasan_save_free_info+0x38/0x58 __kasan_slab_free+0xe4/0x140 kfree+0xb0/0x238 device_release+0xc0/0x2a8 kobject_put+0x1d4/0x46c netdev_run_todo+0x8fc/0x11d0 wilc_netdev_cleanup+0x1e4/0x5cc wilc_bus_remove+0xc8/0xec spi_remove+0x8c/0xac device_release_driver_internal+0x434/0x5f8 unbind_store+0xbc/0x108 kernfs_fop_write_iter+0x398/0x584 vfs_write+0x728/0xf88 ksys_write+0x110/0x1e4 ret_fast_syscall+0x0/0x1c [...] David Mosberger-Tan initial investigation [1] showed that this use-after-free is due to netdevice unregistration during vif list traversal. When unregistering a net device, since the needs_free_netdev has been set to true during registration, the netdevice object is also freed, and as a consequence, the corresponding vif object too, since it is attached to it as private netdevice data. The next occurrence of the loop then tries to access freed vif pointer to the list to move forward in the list. Fix this use-after-free thanks to two mechanisms: - navigate in the list with list_for_each_entry_safe, which allows to safely modify the list as we go through each element. For each element, remove it from the list with list_del_rcu - make sure to wait for RCU grace period end after each vif removal to make sure it is safe to free the corresponding vif too (through unregister_netdev) Since we are in a RCU "modifier" path (not a "reader" path), and because such path is expected not to be concurrent to any other modifier (we are using the vif_mutex lock), we do not need to use RCU list API, that's why we can benefit from list_for_each_entry_safe. [1] https://lore.kernel.org/linux-wireless/ab077dbe58b1ea5de0a3b2ca21f275a07af967d2.camel@egauge.net/

In the Linux kernel, the following vulnerability has been resolved: devlink: fix possible use-after-free and memory leaks in devlink_init() The pernet operations structure for the subsystem must be registered before registering the generic netlink family. Make an unregister in case of unsuccessful registration.