The Linux kernel before 3.15.4 on Intel processors does not properly restrict use of a non-canonical value for the saved RIP address in the case of a system call that does not use IRET, which allows local users to leverage a race condition and gain privileges, or cause a denial of service (double fault), via a crafted application that makes ptrace and fork system calls.

Race condition in the client in IBM Tivoli Storage Manager (TSM) 5.4.0.0 through 5.4.3.6, 5.5.0.0 through 5.5.4.3, 6.1.0.0 through 6.1.5.6, 6.2 before 6.2.5.4, 6.3 before 6.3.2.3, 6.4 before 6.4.2.1, and 7.1 before 7.1.1 on UNIX and Linux allows local users to obtain root privileges via unspecified vectors.

The Linux kernel through 3.14.5 does not properly consider the presence of hugetlb entries, which allows local users to cause a denial of service (memory corruption or system crash) by accessing certain memory locations, as demonstrated by triggering a race condition via numa_maps read operations during hugepage migration, related to fs/proc/task_mmu.c and mm/mempolicy.c.

Race condition in the mac80211 subsystem in the Linux kernel before 3.13.7 allows remote attackers to cause a denial of service (system crash) via network traffic that improperly interacts with the WLAN_STA_PS_STA state (aka power-save mode), related to sta_info.c and tx.c.

Race condition in the ath_tx_aggr_sleep function in drivers/net/wireless/ath/ath9k/xmit.c in the Linux kernel before 3.13.7 allows remote attackers to cause a denial of service (system crash) via a large amount of network traffic that triggers certain list deletions.

Race condition in the tlv handler functionality in the snd_ctl_elem_user_tlv function in sound/core/control.c in the ALSA control implementation in the Linux kernel before 3.15.2 allows local users to obtain sensitive information from kernel memory by leveraging /dev/snd/controlCX access.

Incorrect handling of picture ID in WebRTC in Google Chrome prior to 58.0.3029.96 for Mac, Windows, and Linux allowed a remote attacker to trigger a race condition via a crafted HTML page.

Race condition in the ALSA subsystem in the Linux kernel before 4.13.8 allows local users to cause a denial of service (use-after-free) or possibly have unspecified other impact via crafted /dev/snd/seq ioctl calls, related to sound/core/seq/seq_clientmgr.c and sound/core/seq/seq_ports.c.

In the Linux kernel, the following vulnerability has been resolved: nouveau: fix instmem race condition around ptr stores Running a lot of VK CTS in parallel against nouveau, once every few hours you might see something like this crash. BUG: kernel NULL pointer dereference, address: 0000000000000008 PGD 8000000114e6e067 P4D 8000000114e6e067 PUD 109046067 PMD 0 Oops: 0000 [#1] PREEMPT SMP PTI CPU: 7 PID: 53891 Comm: deqp-vk Not tainted 6.8.0-rc6+ #27 Hardware name: Gigabyte Technology Co., Ltd. Z390 I AORUS PRO WIFI/Z390 I AORUS PRO WIFI-CF, BIOS F8 11/05/2021 RIP: 0010:gp100_vmm_pgt_mem+0xe3/0x180 [nouveau] Code: c7 48 01 c8 49 89 45 58 85 d2 0f 84 95 00 00 00 41 0f b7 46 12 49 8b 7e 08 89 da 42 8d 2c f8 48 8b 47 08 41 83 c7 01 48 89 ee <48> 8b 40 08 ff d0 0f 1f 00 49 8b 7e 08 48 89 d9 48 8d 75 04 48 c1 RSP: 0000:ffffac20c5857838 EFLAGS: 00010202 RAX: 0000000000000000 RBX: 00000000004d8001 RCX: 0000000000000001 RDX: 00000000004d8001 RSI: 00000000000006d8 RDI: ffffa07afe332180 RBP: 00000000000006d8 R08: ffffac20c5857ad0 R09: 0000000000ffff10 R10: 0000000000000001 R11: ffffa07af27e2de0 R12: 000000000000001c R13: ffffac20c5857ad0 R14: ffffa07a96fe9040 R15: 000000000000001c FS: 00007fe395eed7c0(0000) GS:ffffa07e2c980000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000008 CR3: 000000011febe001 CR4: 00000000003706f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: ... ? gp100_vmm_pgt_mem+0xe3/0x180 [nouveau] ? gp100_vmm_pgt_mem+0x37/0x180 [nouveau] nvkm_vmm_iter+0x351/0xa20 [nouveau] ? __pfx_nvkm_vmm_ref_ptes+0x10/0x10 [nouveau] ? __pfx_gp100_vmm_pgt_mem+0x10/0x10 [nouveau] ? __pfx_gp100_vmm_pgt_mem+0x10/0x10 [nouveau] ? __lock_acquire+0x3ed/0x2170 ? __pfx_gp100_vmm_pgt_mem+0x10/0x10 [nouveau] nvkm_vmm_ptes_get_map+0xc2/0x100 [nouveau] ? __pfx_nvkm_vmm_ref_ptes+0x10/0x10 [nouveau] ? __pfx_gp100_vmm_pgt_mem+0x10/0x10 [nouveau] nvkm_vmm_map_locked+0x224/0x3a0 [nouveau] Adding any sort of useful debug usually makes it go away, so I hand wrote the function in a line, and debugged the asm. Every so often pt->memory->ptrs is NULL. This ptrs ptr is set in the nv50_instobj_acquire called from nvkm_kmap. If Thread A and Thread B both get to nv50_instobj_acquire around the same time, and Thread A hits the refcount_set line, and in lockstep thread B succeeds at refcount_inc_not_zero, there is a chance the ptrs value won't have been stored since refcount_set is unordered. Force a memory barrier here, I picked smp_mb, since we want it on all CPUs and it's write followed by a read. v2: use paired smp_rmb/smp_wmb.

Race condition in the do_add_counters function in netfilter for Linux kernel 2.6.16 allows local users with CAP_NET_ADMIN capabilities to read kernel memory by triggering the race condition in a way that produces a size value that is inconsistent with allocated memory, which leads to a buffer over-read in IPT_ENTRY_ITERATE.

An issue was discovered in the Linux kernel through 4.17.2. vbg_misc_device_ioctl() in drivers/virt/vboxguest/vboxguest_linux.c reads the same user data twice with copy_from_user. The header part of the user data is double-fetched, and a malicious user thread can tamper with the critical variables (hdr.size_in and hdr.size_out) in the header between the two fetches because of a race condition, leading to severe kernel errors, such as buffer over-accesses. This bug can cause a local denial of service and information leakage.

The n_tty_write function in drivers/tty/n_tty.c in the Linux kernel through 3.14.3 does not properly manage tty driver access in the "LECHO & !OPOST" case, which allows local users to cause a denial of service (memory corruption and system crash) or gain privileges by triggering a race condition involving read and write operations with long strings.

In the Linux kernel before 5.4.16, a race condition in tty->disc_data handling in the slip and slcan line discipline could lead to a use-after-free, aka CID-0ace17d56824. This affects drivers/net/slip/slip.c and drivers/net/can/slcan.c.

Race condition in the inet_frag_intern function in net/ipv4/inet_fragment.c in the Linux kernel through 3.13.6 allows remote attackers to cause a denial of service (use-after-free error) or possibly have unspecified other impact via a large series of fragmented ICMP Echo Request packets to a system with a heavy CPU load.

Multiple race conditions in ipc/shm.c in the Linux kernel before 3.12.2 allow local users to cause a denial of service (use-after-free and system crash) or possibly have unspecified other impact via a crafted application that uses shmctl IPC_RMID operations in conjunction with other shm system calls.

A race condition in navigation in Google Chrome prior to 58.0.3029.81 for Linux, Windows, and Mac allowed a remote attacker to spoof the contents of the Omnibox (URL bar) via a crafted HTML page.

In the Linux kernel 4.19 through 5.6.7 on the s390 platform, code execution may occur because of a race condition, as demonstrated by code in enable_sacf_uaccess in arch/s390/lib/uaccess.c that fails to protect against a concurrent page table upgrade, aka CID-3f777e19d171. A crash could also occur.

The __mptctl_ioctl function in drivers/message/fusion/mptctl.c in the Linux kernel before 5.4.14 allows local users to hold an incorrect lock during the ioctl operation and trigger a race condition, i.e., a "double fetch" vulnerability, aka CID-28d76df18f0a. NOTE: the vendor states "The security impact of this bug is not as bad as it could have been because these operations are all privileged and root already has enormous destructive power."

In the Linux kernel, the following vulnerability has been resolved: tty: n_gsm: fix race condition in status line change on dead connections gsm_cleanup_mux() cleans up the gsm by closing all DLCIs, stopping all timers, removing the virtual tty devices and clearing the data queues. This procedure, however, may cause subsequent changes of the virtual modem status lines of a DLCI. More data is being added the outgoing data queue and the deleted kick timer is restarted to handle this. At this point many resources have already been removed by the cleanup procedure. Thus, a kernel panic occurs. Fix this by proving in gsm_modem_update() that the cleanup procedure has not been started and the mux is still alive. Note that writing to a virtual tty is already protected by checks against the DLCI specific connection state.

Race condition in the smb_send_rqst function in fs/cifs/transport.c in the Linux kernel before 3.7.2 allows local users to cause a denial of service (NULL pointer dereference and OOPS) or possibly have unspecified other impact via vectors involving a reconnection event.

In the Linux kernel, the following vulnerability has been resolved: exfat: fix random stack corruption after get_block When get_block is called with a buffer_head allocated on the stack, such as do_mpage_readpage, stack corruption due to buffer_head UAF may occur in the following race condition situation. <CPU 0> <CPU 1> mpage_read_folio <<bh on stack>> do_mpage_readpage exfat_get_block bh_read __bh_read get_bh(bh) submit_bh wait_on_buffer ... end_buffer_read_sync __end_buffer_read_notouch unlock_buffer <<keep going>> ... ... ... ... <<bh is not valid out of mpage_read_folio>> . . another_function <<variable A on stack>> put_bh(bh) atomic_dec(bh->b_count) * stack corruption here * This patch returns -EAGAIN if a folio does not have buffers when bh_read needs to be called. By doing this, the caller can fallback to functions like block_read_full_folio(), create a buffer_head in the folio, and then call get_block again. Let's do not call bh_read() with on-stack buffer_head.

An issue was discovered in set_con2fb_map in drivers/video/fbdev/core/fbcon.c in the Linux kernel before 6.2.12. Because an assignment occurs only for the first vc, the fbcon_registered_fb and fbcon_display arrays can be desynchronized in fbcon_mode_deleted (the con2fb_map points at the old fb_info).

An issue was discovered in the Linux kernel before 6.3.2. A use-after-free was found in cedrus_remove in drivers/staging/media/sunxi/cedrus/cedrus.c.

An issue was discovered in the Linux kernel before 6.3.2. A use-after-free was found in saa7134_finidev in drivers/media/pci/saa7134/saa7134-core.c.

An issue was discovered in the Linux kernel through 6.3.8. A use-after-free was found in ravb_remove in drivers/net/ethernet/renesas/ravb_main.c.

A race condition occurred between the functions lmLogClose and txEnd in JFS, in the Linux Kernel, executed in different threads. This flaw allows a local attacker with normal user privileges to crash the system or leak internal kernel information.

A race condition vulnerability was found in the vmwgfx driver in the Linux kernel. The flaw exists within the handling of GEM objects. The issue results from improper locking when performing operations on an object. This flaw allows a local privileged user to disclose information in the context of the kernel.

In a Linux KVM guest that has PV TLB enabled, a process in the guest kernel may be able to read memory locations from another process in the same guest. This problem is limit to the host running linux kernel 4.10 with a guest running linux kernel 4.16 or later. The problem mainly affects AMD processors but Intel CPUs cannot be ruled out.

A flaw was found in the Linux kernel's ksmbd, a high-performance in-kernel SMB server. The specific flaw exists within the processing of SMB2_TREE_DISCONNECT commands. The issue results from the lack of proper locking when performing operations on an object. An attacker can leverage this vulnerability to execute code in the context of the kernel.

The Linux kernel before 6.2.9 has a race condition and resultant use-after-free in drivers/net/ethernet/qualcomm/emac/emac.c if a physically proximate attacker unplugs an emac based device.

In the Linux kernel, the following vulnerability has been resolved: tcp: TX zerocopy should not sense pfmemalloc status We got a recent syzbot report [1] showing a possible misuse of pfmemalloc page status in TCP zerocopy paths. Indeed, for pages coming from user space or other layers, using page_is_pfmemalloc() is moot, and possibly could give false positives. There has been attempts to make page_is_pfmemalloc() more robust, but not using it in the first place in this context is probably better, removing cpu cycles. Note to stable teams : You need to backport 84ce071e38a6 ("net: introduce __skb_fill_page_desc_noacc") as a prereq. Race is more probable after commit c07aea3ef4d4 ("mm: add a signature in struct page") because page_is_pfmemalloc() is now using low order bit from page->lru.next, which can change more often than page->index. Low order bit should never be set for lru.next (when used as an anchor in LRU list), so KCSAN report is mostly a false positive. Backporting to older kernel versions seems not necessary. [1] BUG: KCSAN: data-race in lru_add_fn / tcp_build_frag write to 0xffffea0004a1d2c8 of 8 bytes by task 18600 on cpu 0: __list_add include/linux/list.h:73 [inline] list_add include/linux/list.h:88 [inline] lruvec_add_folio include/linux/mm_inline.h:105 [inline] lru_add_fn+0x440/0x520 mm/swap.c:228 folio_batch_move_lru+0x1e1/0x2a0 mm/swap.c:246 folio_batch_add_and_move mm/swap.c:263 [inline] folio_add_lru+0xf1/0x140 mm/swap.c:490 filemap_add_folio+0xf8/0x150 mm/filemap.c:948 __filemap_get_folio+0x510/0x6d0 mm/filemap.c:1981 pagecache_get_page+0x26/0x190 mm/folio-compat.c:104 grab_cache_page_write_begin+0x2a/0x30 mm/folio-compat.c:116 ext4_da_write_begin+0x2dd/0x5f0 fs/ext4/inode.c:2988 generic_perform_write+0x1d4/0x3f0 mm/filemap.c:3738 ext4_buffered_write_iter+0x235/0x3e0 fs/ext4/file.c:270 ext4_file_write_iter+0x2e3/0x1210 call_write_iter include/linux/fs.h:2187 [inline] new_sync_write fs/read_write.c:491 [inline] vfs_write+0x468/0x760 fs/read_write.c:578 ksys_write+0xe8/0x1a0 fs/read_write.c:631 __do_sys_write fs/read_write.c:643 [inline] __se_sys_write fs/read_write.c:640 [inline] __x64_sys_write+0x3e/0x50 fs/read_write.c:640 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd read to 0xffffea0004a1d2c8 of 8 bytes by task 18611 on cpu 1: page_is_pfmemalloc include/linux/mm.h:1740 [inline] __skb_fill_page_desc include/linux/skbuff.h:2422 [inline] skb_fill_page_desc include/linux/skbuff.h:2443 [inline] tcp_build_frag+0x613/0xb20 net/ipv4/tcp.c:1018 do_tcp_sendpages+0x3e8/0xaf0 net/ipv4/tcp.c:1075 tcp_sendpage_locked net/ipv4/tcp.c:1140 [inline] tcp_sendpage+0x89/0xb0 net/ipv4/tcp.c:1150 inet_sendpage+0x7f/0xc0 net/ipv4/af_inet.c:833 kernel_sendpage+0x184/0x300 net/socket.c:3561 sock_sendpage+0x5a/0x70 net/socket.c:1054 pipe_to_sendpage+0x128/0x160 fs/splice.c:361 splice_from_pipe_feed fs/splice.c:415 [inline] __splice_from_pipe+0x222/0x4d0 fs/splice.c:559 splice_from_pipe fs/splice.c:594 [inline] generic_splice_sendpage+0x89/0xc0 fs/splice.c:743 do_splice_from fs/splice.c:764 [inline] direct_splice_actor+0x80/0xa0 fs/splice.c:931 splice_direct_to_actor+0x305/0x620 fs/splice.c:886 do_splice_direct+0xfb/0x180 fs/splice.c:974 do_sendfile+0x3bf/0x910 fs/read_write.c:1249 __do_sys_sendfile64 fs/read_write.c:1317 [inline] __se_sys_sendfile64 fs/read_write.c:1303 [inline] __x64_sys_sendfile64+0x10c/0x150 fs/read_write.c:1303 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd value changed: 0x0000000000000000 -> 0xffffea0004a1d288 Reported by Kernel Concurrency Sanitizer on: CPU: 1 PID: 18611 Comm: syz-executor.4 Not tainted 6.0.0-rc2-syzkaller-00248-ge022620b5d05-dirty #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/22/2022

In the Linux kernel, the following vulnerability has been resolved: riscv: fix race when vmap stack overflow Currently, when detecting vmap stack overflow, riscv firstly switches to the so called shadow stack, then use this shadow stack to call the get_overflow_stack() to get the overflow stack. However, there's a race here if two or more harts use the same shadow stack at the same time. To solve this race, we introduce spin_shadow_stack atomic var, which will be swap between its own address and 0 in atomic way, when the var is set, it means the shadow_stack is being used; when the var is cleared, it means the shadow_stack isn't being used. [Palmer: Add AQ to the swap, and also some comments.]

Race condition in the International Components for Unicode (ICU) functionality in Google Chrome before 25.0.1364.97 on Windows and Linux, and before 25.0.1364.99 on Mac OS X, allows remote attackers to cause a denial of service or possibly have unspecified other impact via unknown vectors.

A race condition was found in util-linux before 2.32.1 in the way su handled the management of child processes. A local authenticated attacker could use this flaw to kill other processes with root privileges under specific conditions.

In the Linux kernel, the following vulnerability has been resolved: binder: fix node UAF in binder_add_freeze_work() In binder_add_freeze_work() we iterate over the proc->nodes with the proc->inner_lock held. However, this lock is temporarily dropped in order to acquire the node->lock first (lock nesting order). This can race with binder_node_release() and trigger a use-after-free: ================================================================== BUG: KASAN: slab-use-after-free in _raw_spin_lock+0xe4/0x19c Write of size 4 at addr ffff53c04c29dd04 by task freeze/640 CPU: 5 UID: 0 PID: 640 Comm: freeze Not tainted 6.11.0-07343-ga727812a8d45 #17 Hardware name: linux,dummy-virt (DT) Call trace: _raw_spin_lock+0xe4/0x19c binder_add_freeze_work+0x148/0x478 binder_ioctl+0x1e70/0x25ac __arm64_sys_ioctl+0x124/0x190 Allocated by task 637: __kmalloc_cache_noprof+0x12c/0x27c binder_new_node+0x50/0x700 binder_transaction+0x35ac/0x6f74 binder_thread_write+0xfb8/0x42a0 binder_ioctl+0x18f0/0x25ac __arm64_sys_ioctl+0x124/0x190 Freed by task 637: kfree+0xf0/0x330 binder_thread_read+0x1e88/0x3a68 binder_ioctl+0x16d8/0x25ac __arm64_sys_ioctl+0x124/0x190 ================================================================== Fix the race by taking a temporary reference on the node before releasing the proc->inner lock. This ensures the node remains alive while in use.

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---

An issue was discovered in the Linux kernel through 6.0.9. drivers/char/xillybus/xillyusb.c has a race condition and use-after-free during physical removal of a USB device.

In the Linux kernel, the following vulnerability has been resolved: net/mlx5: fs, lock FTE when checking if active The referenced commits introduced a two-step process for deleting FTEs: - Lock the FTE, delete it from hardware, set the hardware deletion function to NULL and unlock the FTE. - Lock the parent flow group, delete the software copy of the FTE, and remove it from the xarray. However, this approach encounters a race condition if a rule with the same match value is added simultaneously. In this scenario, fs_core may set the hardware deletion function to NULL prematurely, causing a panic during subsequent rule deletions. To prevent this, ensure the active flag of the FTE is checked under a lock, which will prevent the fs_core layer from attaching a new steering rule to an FTE that is in the process of deletion. [ 438.967589] MOSHE: 2496 mlx5_del_flow_rules del_hw_func [ 438.968205] ------------[ cut here ]------------ [ 438.968654] refcount_t: decrement hit 0; leaking memory. [ 438.969249] WARNING: CPU: 0 PID: 8957 at lib/refcount.c:31 refcount_warn_saturate+0xfb/0x110 [ 438.970054] Modules linked in: act_mirred cls_flower act_gact sch_ingress openvswitch nsh mlx5_vdpa vringh vhost_iotlb vdpa mlx5_ib mlx5_core xt_conntrack xt_MASQUERADE nf_conntrack_netlink nfnetlink xt_addrtype iptable_nat nf_nat br_netfilter rpcsec_gss_krb5 auth_rpcgss oid_registry overlay rpcrdma rdma_ucm ib_iser libiscsi scsi_transport_iscsi ib_umad rdma_cm ib_ipoib iw_cm ib_cm ib_uverbs ib_core zram zsmalloc fuse [last unloaded: cls_flower] [ 438.973288] CPU: 0 UID: 0 PID: 8957 Comm: tc Not tainted 6.12.0-rc1+ #8 [ 438.973888] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014 [ 438.974874] RIP: 0010:refcount_warn_saturate+0xfb/0x110 [ 438.975363] Code: 40 66 3b 82 c6 05 16 e9 4d 01 01 e8 1f 7c a0 ff 0f 0b c3 cc cc cc cc 48 c7 c7 10 66 3b 82 c6 05 fd e8 4d 01 01 e8 05 7c a0 ff <0f> 0b c3 cc cc cc cc 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 90 [ 438.976947] RSP: 0018:ffff888124a53610 EFLAGS: 00010286 [ 438.977446] RAX: 0000000000000000 RBX: ffff888119d56de0 RCX: 0000000000000000 [ 438.978090] RDX: ffff88852c828700 RSI: ffff88852c81b3c0 RDI: ffff88852c81b3c0 [ 438.978721] RBP: ffff888120fa0e88 R08: 0000000000000000 R09: ffff888124a534b0 [ 438.979353] R10: 0000000000000001 R11: 0000000000000001 R12: ffff888119d56de0 [ 438.979979] R13: ffff888120fa0ec0 R14: ffff888120fa0ee8 R15: ffff888119d56de0 [ 438.980607] FS: 00007fe6dcc0f800(0000) GS:ffff88852c800000(0000) knlGS:0000000000000000 [ 438.983984] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 438.984544] CR2: 00000000004275e0 CR3: 0000000186982001 CR4: 0000000000372eb0 [ 438.985205] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 438.985842] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 438.986507] Call Trace: [ 438.986799] <TASK> [ 438.987070] ? __warn+0x7d/0x110 [ 438.987426] ? refcount_warn_saturate+0xfb/0x110 [ 438.987877] ? report_bug+0x17d/0x190 [ 438.988261] ? prb_read_valid+0x17/0x20 [ 438.988659] ? handle_bug+0x53/0x90 [ 438.989054] ? exc_invalid_op+0x14/0x70 [ 438.989458] ? asm_exc_invalid_op+0x16/0x20 [ 438.989883] ? refcount_warn_saturate+0xfb/0x110 [ 438.990348] mlx5_del_flow_rules+0x2f7/0x340 [mlx5_core] [ 438.990932] __mlx5_eswitch_del_rule+0x49/0x170 [mlx5_core] [ 438.991519] ? mlx5_lag_is_sriov+0x3c/0x50 [mlx5_core] [ 438.992054] ? xas_load+0x9/0xb0 [ 438.992407] mlx5e_tc_rule_unoffload+0x45/0xe0 [mlx5_core] [ 438.993037] mlx5e_tc_del_fdb_flow+0x2a6/0x2e0 [mlx5_core] [ 438.993623] mlx5e_flow_put+0x29/0x60 [mlx5_core] [ 438.994161] mlx5e_delete_flower+0x261/0x390 [mlx5_core] [ 438.994728] tc_setup_cb_destroy+0xb9/0x190 [ 438.995150] fl_hw_destroy_filter+0x94/0xc0 [cls_flower] [ 438.995650] fl_change+0x11a4/0x13c0 [cls_flower] [ 438.996105] tc_new_tfilter+0x347/0xbc0 [ 438.996503] ? __ ---truncated---

In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix use-after-free in SMB request handling A race condition exists between SMB request handling in `ksmbd_conn_handler_loop()` and the freeing of `ksmbd_conn` in the workqueue handler `handle_ksmbd_work()`. This leads to a UAF. - KASAN: slab-use-after-free Read in handle_ksmbd_work - KASAN: slab-use-after-free in rtlock_slowlock_locked This race condition arises as follows: - `ksmbd_conn_handler_loop()` waits for `conn->r_count` to reach zero: `wait_event(conn->r_count_q, atomic_read(&conn->r_count) == 0);` - Meanwhile, `handle_ksmbd_work()` decrements `conn->r_count` using `atomic_dec_return(&conn->r_count)`, and if it reaches zero, calls `ksmbd_conn_free()`, which frees `conn`. - However, after `handle_ksmbd_work()` decrements `conn->r_count`, it may still access `conn->r_count_q` in the following line: `waitqueue_active(&conn->r_count_q)` or `wake_up(&conn->r_count_q)` This results in a UAF, as `conn` has already been freed. The discovery of this UAF can be referenced in the following PR for syzkaller's support for SMB requests.

An issue was discovered in the Linux kernel through 6.0.9. drivers/media/dvb-core/dvb_net.c has a .disconnect versus dvb_device_open race condition that leads to a use-after-free.

An issue was discovered in the Linux kernel through 6.0.9. drivers/media/dvb-core/dvbdev.c has a use-after-free, related to dvb_register_device dynamically allocating fops.

In the Linux kernel, the following vulnerability has been resolved: mm/mremap: fix move_normal_pmd/retract_page_tables race In mremap(), move_page_tables() looks at the type of the PMD entry and the specified address range to figure out by which method the next chunk of page table entries should be moved. At that point, the mmap_lock is held in write mode, but no rmap locks are held yet. For PMD entries that point to page tables and are fully covered by the source address range, move_pgt_entry(NORMAL_PMD, ...) is called, which first takes rmap locks, then does move_normal_pmd(). move_normal_pmd() takes the necessary page table locks at source and destination, then moves an entire page table from the source to the destination. The problem is: The rmap locks, which protect against concurrent page table removal by retract_page_tables() in the THP code, are only taken after the PMD entry has been read and it has been decided how to move it. So we can race as follows (with two processes that have mappings of the same tmpfs file that is stored on a tmpfs mount with huge=advise); note that process A accesses page tables through the MM while process B does it through the file rmap: process A process B ========= ========= mremap mremap_to move_vma move_page_tables get_old_pmd alloc_new_pmd *** PREEMPT *** madvise(MADV_COLLAPSE) do_madvise madvise_walk_vmas madvise_vma_behavior madvise_collapse hpage_collapse_scan_file collapse_file retract_page_tables i_mmap_lock_read(mapping) pmdp_collapse_flush i_mmap_unlock_read(mapping) move_pgt_entry(NORMAL_PMD, ...) take_rmap_locks move_normal_pmd drop_rmap_locks When this happens, move_normal_pmd() can end up creating bogus PMD entries in the line `pmd_populate(mm, new_pmd, pmd_pgtable(pmd))`. The effect depends on arch-specific and machine-specific details; on x86, you can end up with physical page 0 mapped as a page table, which is likely exploitable for user->kernel privilege escalation. Fix the race by letting process B recheck that the PMD still points to a page table after the rmap locks have been taken. Otherwise, we bail and let the caller fall back to the PTE-level copying path, which will then bail immediately at the pmd_none() check. Bug reachability: Reaching this bug requires that you can create shmem/file THP mappings - anonymous THP uses different code that doesn't zap stuff under rmap locks. File THP is gated on an experimental config flag (CONFIG_READ_ONLY_THP_FOR_FS), so on normal distro kernels you need shmem THP to hit this bug. As far as I know, getting shmem THP normally requires that you can mount your own tmpfs with the right mount flags, which would require creating your own user+mount namespace; though I don't know if some distros maybe enable shmem THP by default or something like that. Bug impact: This issue can likely be used for user->kernel privilege escalation when it is reachable.

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.

A race condition in the x86 KVM subsystem in the Linux kernel through 6.1-rc6 allows guest OS users to cause a denial of service (host OS crash or host OS memory corruption) when nested virtualisation and the TDP MMU are enabled.

An issue was discovered in the Linux kernel through 6.0.9. drivers/media/dvb-core/dvb_frontend.c has a race condition that can cause a use-after-free when a device is disconnected.

Race condition in drivers/tty/n_hdlc.c in the Linux kernel through 4.10.1 allows local users to gain privileges or cause a denial of service (double free) by setting the HDLC line discipline.

An issue was discovered in the Linux kernel through 6.0.6. drivers/char/pcmcia/cm4040_cs.c has a race condition and resultant use-after-free if a physically proximate attacker removes a PCMCIA device while calling open(), aka a race condition between cm4040_open() and reader_detach().

The dm_get_from_kobject function in drivers/md/dm.c in the Linux kernel before 4.14.3 allow local users to cause a denial of service (BUG) by leveraging a race condition with __dm_destroy during creation and removal of DM devices.

An issue was discovered in the Linux kernel through 6.0.6. drivers/char/pcmcia/scr24x_cs.c has a race condition and resultant use-after-free if a physically proximate attacker removes a PCMCIA device while calling open(), aka a race condition between scr24x_open() and scr24x_remove().