In the Linux kernel, the following vulnerability has been resolved: KVM: Always flush async #PF workqueue when vCPU is being destroyed Always flush the per-vCPU async #PF workqueue when a vCPU is clearing its completion queue, e.g. when a VM and all its vCPUs is being destroyed. KVM must ensure that none of its workqueue callbacks is running when the last reference to the KVM _module_ is put. Gifting a reference to the associated VM prevents the workqueue callback from dereferencing freed vCPU/VM memory, but does not prevent the KVM module from being unloaded before the callback completes. Drop the misguided VM refcount gifting, as calling kvm_put_kvm() from async_pf_execute() if kvm_put_kvm() flushes the async #PF workqueue will result in deadlock. async_pf_execute() can't return until kvm_put_kvm() finishes, and kvm_put_kvm() can't return until async_pf_execute() finishes: WARNING: CPU: 8 PID: 251 at virt/kvm/kvm_main.c:1435 kvm_put_kvm+0x2d/0x320 [kvm] Modules linked in: vhost_net vhost vhost_iotlb tap kvm_intel kvm irqbypass CPU: 8 PID: 251 Comm: kworker/8:1 Tainted: G W 6.6.0-rc1-e7af8d17224a-x86/gmem-vm #119 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 Workqueue: events async_pf_execute [kvm] RIP: 0010:kvm_put_kvm+0x2d/0x320 [kvm] Call Trace: <TASK> async_pf_execute+0x198/0x260 [kvm] process_one_work+0x145/0x2d0 worker_thread+0x27e/0x3a0 kthread+0xba/0xe0 ret_from_fork+0x2d/0x50 ret_from_fork_asm+0x11/0x20 </TASK> ---[ end trace 0000000000000000 ]--- INFO: task kworker/8:1:251 blocked for more than 120 seconds. Tainted: G W 6.6.0-rc1-e7af8d17224a-x86/gmem-vm #119 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/8:1 state:D stack:0 pid:251 ppid:2 flags:0x00004000 Workqueue: events async_pf_execute [kvm] Call Trace: <TASK> __schedule+0x33f/0xa40 schedule+0x53/0xc0 schedule_timeout+0x12a/0x140 __wait_for_common+0x8d/0x1d0 __flush_work.isra.0+0x19f/0x2c0 kvm_clear_async_pf_completion_queue+0x129/0x190 [kvm] kvm_arch_destroy_vm+0x78/0x1b0 [kvm] kvm_put_kvm+0x1c1/0x320 [kvm] async_pf_execute+0x198/0x260 [kvm] process_one_work+0x145/0x2d0 worker_thread+0x27e/0x3a0 kthread+0xba/0xe0 ret_from_fork+0x2d/0x50 ret_from_fork_asm+0x11/0x20 </TASK> If kvm_clear_async_pf_completion_queue() actually flushes the workqueue, then there's no need to gift async_pf_execute() a reference because all invocations of async_pf_execute() will be forced to complete before the vCPU and its VM are destroyed/freed. And that in turn fixes the module unloading bug as __fput() won't do module_put() on the last vCPU reference until the vCPU has been freed, e.g. if closing the vCPU file also puts the last reference to the KVM module. Note that kvm_check_async_pf_completion() may also take the work item off the completion queue and so also needs to flush the work queue, as the work will not be seen by kvm_clear_async_pf_completion_queue(). Waiting on the workqueue could theoretically delay a vCPU due to waiting for the work to complete, but that's a very, very small chance, and likely a very small delay. kvm_arch_async_page_present_queued() unconditionally makes a new request, i.e. will effectively delay entering the guest, so the remaining work is really just: trace_kvm_async_pf_completed(addr, cr2_or_gpa); __kvm_vcpu_wake_up(vcpu); mmput(mm); and mmput() can't drop the last reference to the page tables if the vCPU is still alive, i.e. the vCPU won't get stuck tearing down page tables. Add a helper to do the flushing, specifically to deal with "wakeup all" work items, as they aren't actually work items, i.e. are never placed in a workqueue. Trying to flush a bogus workqueue entry rightly makes __flush_work() complain (kudos to whoever added that sanity check). Note, commit 5f6de5cbebee ("KVM: Prevent module exit until al ---truncated---

net/bluetooth/hci_request.c in the Linux kernel through 5.12.2 has a race condition for removal of the HCI controller.

The networking implementation in the Linux kernel through 4.3.3, as used in Android and other products, does not validate protocol identifiers for certain protocol families, which allows local users to cause a denial of service (NULL function pointer dereference and system crash) or possibly gain privileges by leveraging CLONE_NEWUSER support to execute a crafted SOCK_RAW application.

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

This vulnerability allows local attackers to escalate privileges on affected installations of Linux Kernel 5.11.15. An attacker must first obtain the ability to execute low-privileged code on the target system in order to exploit this vulnerability. The specific flaw exists within the handling of eBPF programs. The issue results from the lack of proper validation of user-supplied eBPF programs prior to executing them. An attacker can leverage this vulnerability to escalate privileges and execute arbitrary code in the context of the kernel. Was ZDI-CAN-13661.

In PHP versions 7.3.x up to and including 7.3.31, 7.4.x below 7.4.25 and 8.0.x below 8.0.12, when running PHP FPM SAPI with main FPM daemon process running as root and child worker processes running as lower-privileged users, it is possible for the child processes to access memory shared with the main process and write to it, modifying it in a way that would cause the root process to conduct invalid memory reads and writes, which can be used to escalate privileges from local unprivileged user to the root user.

A race condition in Linux kernel SCTP sockets (net/sctp/socket.c) before 5.12-rc8 can lead to kernel privilege escalation from the context of a network service or an unprivileged process. If sctp_destroy_sock is called without sock_net(sk)->sctp.addr_wq_lock then an element is removed from the auto_asconf_splist list without any proper locking. This can be exploited by an attacker with network service privileges to escalate to root or from the context of an unprivileged user directly if a BPF_CGROUP_INET_SOCK_CREATE is attached which denies creation of some SCTP socket.

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: net: do not delay dst_entries_add() in dst_release() dst_entries_add() uses per-cpu data that might be freed at netns dismantle from ip6_route_net_exit() calling dst_entries_destroy() Before ip6_route_net_exit() can be called, we release all the dsts associated with this netns, via calls to dst_release(), which waits an rcu grace period before calling dst_destroy() dst_entries_add() use in dst_destroy() is racy, because dst_entries_destroy() could have been called already. Decrementing the number of dsts must happen sooner. Notes: 1) in CONFIG_XFRM case, dst_destroy() can call dst_release_immediate(child), this might also cause UAF if the child does not have DST_NOCOUNT set. IPSEC maintainers might take a look and see how to address this. 2) There is also discussion about removing this count of dst, which might happen in future kernels.

In the Linux kernel, the following vulnerability has been resolved: drm/amdgpu: Using uninitialized value *size when calling amdgpu_vce_cs_reloc Initialize the size before calling amdgpu_vce_cs_reloc, such as case 0x03000001. V2: To really improve the handling we would actually need to have a separate value of 0xffffffff.(Christian)

In the Linux kernel, the following vulnerability has been resolved: gve: Account for stopped queues when reading NIC stats We now account for the fact that the NIC might send us stats for a subset of queues. Without this change, gve_get_ethtool_stats might make an invalid access on the priv->stats_report->stats array.

In the Linux kernel, the following vulnerability has been resolved: mailbox: mtk-cmdq: Fix pm_runtime_get_sync() warning in mbox shutdown The return value of pm_runtime_get_sync() in cmdq_mbox_shutdown() will return 1 when pm runtime state is active, and we don't want to get the warning message in this case. So we change the return value < 0 for WARN_ON().

In the Linux kernel, the following vulnerability has been resolved: f2fs: compress: fix to cover {reserve,release}_compress_blocks() w/ cp_rwsem lock It needs to cover {reserve,release}_compress_blocks() w/ cp_rwsem lock to avoid racing with checkpoint, otherwise, filesystem metadata including blkaddr in dnode, inode fields and .total_valid_block_count may be corrupted after SPO case.

In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_tables: Fix potential data-race in __nft_expr_type_get() nft_unregister_expr() can concurrent with __nft_expr_type_get(), and there is not any protection when iterate over nf_tables_expressions list in __nft_expr_type_get(). Therefore, there is potential data-race of nf_tables_expressions list entry. Use list_for_each_entry_rcu() to iterate over nf_tables_expressions list in __nft_expr_type_get(), and use rcu_read_lock() in the caller nft_expr_type_get() to protect the entire type query process.

In the Linux kernel, the following vulnerability has been resolved: fs/proc/task_mmu: move mmu notification mechanism inside mm lock Move mmu notification mechanism inside mm lock to prevent race condition in other components which depend on it. The notifier will invalidate memory range. Depending upon the number of iterations, different memory ranges would be invalidated. The following warning would be removed by this patch: WARNING: CPU: 0 PID: 5067 at arch/x86/kvm/../../../virt/kvm/kvm_main.c:734 kvm_mmu_notifier_change_pte+0x860/0x960 arch/x86/kvm/../../../virt/kvm/kvm_main.c:734 There is no behavioural and performance change with this patch when there is no component registered with the mmu notifier. [akpm@linux-foundation.org: narrow the scope of `range', per Sean]

In the Linux kernel, the following vulnerability has been resolved: wifi: iwlegacy: Clear stale interrupts before resuming device iwl4965 fails upon resume from hibernation on my laptop. The reason seems to be a stale interrupt which isn't being cleared out before interrupts are enabled. We end up with a race beween the resume trying to bring things back up, and the restart work (queued form the interrupt handler) trying to bring things down. Eventually the whole thing blows up. Fix the problem by clearing out any stale interrupts before interrupts get enabled during resume. Here's a debug log of the indicent: [ 12.042589] ieee80211 phy0: il_isr ISR inta 0x00000080, enabled 0xaa00008b, fh 0x00000000 [ 12.042625] ieee80211 phy0: il4965_irq_tasklet inta 0x00000080, enabled 0x00000000, fh 0x00000000 [ 12.042651] iwl4965 0000:10:00.0: RF_KILL bit toggled to enable radio. [ 12.042653] iwl4965 0000:10:00.0: On demand firmware reload [ 12.042690] ieee80211 phy0: il4965_irq_tasklet End inta 0x00000000, enabled 0xaa00008b, fh 0x00000000, flags 0x00000282 [ 12.052207] ieee80211 phy0: il4965_mac_start enter [ 12.052212] ieee80211 phy0: il_prep_station Add STA to driver ID 31: ff:ff:ff:ff:ff:ff [ 12.052244] ieee80211 phy0: il4965_set_hw_ready hardware ready [ 12.052324] ieee80211 phy0: il_apm_init Init card's basic functions [ 12.052348] ieee80211 phy0: il_apm_init L1 Enabled; Disabling L0S [ 12.055727] ieee80211 phy0: il4965_load_bsm Begin load bsm [ 12.056140] ieee80211 phy0: il4965_verify_bsm Begin verify bsm [ 12.058642] ieee80211 phy0: il4965_verify_bsm BSM bootstrap uCode image OK [ 12.058721] ieee80211 phy0: il4965_load_bsm BSM write complete, poll 1 iterations [ 12.058734] ieee80211 phy0: __il4965_up iwl4965 is coming up [ 12.058737] ieee80211 phy0: il4965_mac_start Start UP work done. [ 12.058757] ieee80211 phy0: __il4965_down iwl4965 is going down [ 12.058761] ieee80211 phy0: il_scan_cancel_timeout Scan cancel timeout [ 12.058762] ieee80211 phy0: il_do_scan_abort Not performing scan to abort [ 12.058765] ieee80211 phy0: il_clear_ucode_stations Clearing ucode stations in driver [ 12.058767] ieee80211 phy0: il_clear_ucode_stations No active stations found to be cleared [ 12.058819] ieee80211 phy0: _il_apm_stop Stop card, put in low power state [ 12.058827] ieee80211 phy0: _il_apm_stop_master stop master [ 12.058864] ieee80211 phy0: il4965_clear_free_frames 0 frames on pre-allocated heap on clear. [ 12.058869] ieee80211 phy0: Hardware restart was requested [ 16.132299] iwl4965 0000:10:00.0: START_ALIVE timeout after 4000ms. [ 16.132303] ------------[ cut here ]------------ [ 16.132304] Hardware became unavailable upon resume. This could be a software issue prior to suspend or a hardware issue. [ 16.132338] WARNING: CPU: 0 PID: 181 at net/mac80211/util.c:1826 ieee80211_reconfig+0x8f/0x14b0 [mac80211] [ 16.132390] Modules linked in: ctr ccm sch_fq_codel xt_tcpudp xt_multiport xt_state iptable_filter iptable_nat nf_nat nf_conntrack nf_defrag_ipv4 ip_tables x_tables binfmt_misc joydev mousedev btusb btrtl btintel btbcm bluetooth ecdh_generic ecc iTCO_wdt i2c_dev iwl4965 iwlegacy coretemp snd_hda_codec_analog pcspkr psmouse mac80211 snd_hda_codec_generic libarc4 sdhci_pci cqhci sha256_generic sdhci libsha256 firewire_ohci snd_hda_intel snd_intel_dspcfg mmc_core snd_hda_codec snd_hwdep firewire_core led_class iosf_mbi snd_hda_core uhci_hcd lpc_ich crc_itu_t cfg80211 ehci_pci ehci_hcd snd_pcm usbcore mfd_core rfkill snd_timer snd usb_common soundcore video parport_pc parport intel_agp wmi intel_gtt backlight e1000e agpgart evdev [ 16.132456] CPU: 0 UID: 0 PID: 181 Comm: kworker/u8:6 Not tainted 6.11.0-cl+ #143 [ 16.132460] Hardware name: Hewlett-Packard HP Compaq 6910p/30BE, BIOS 68MCU Ver. F.19 07/06/2010 [ 16.132463] Workqueue: async async_run_entry_fn [ 16.132469] RIP: 0010:ieee80211_reconfig+0x8f/0x14b0 [mac80211] [ 16.132501] Code: da 02 00 0 ---truncated---

A vulnerability, which was classified as critical, has been found in Linux Kernel. Affected by this issue is the function tst_timer of the file drivers/atm/idt77252.c of the component IPsec. The manipulation leads to use after free. It is recommended to apply a patch to fix this issue. VDB-211934 is the identifier assigned to this vulnerability.

In the Linux kernel, the following vulnerability has been resolved: media: mediatek: vcodec: adding lock to protect encoder context list Add a lock for the ctx_list, to avoid accessing a NULL pointer within the 'vpu_enc_ipi_handler' function when the ctx_list has been deleted due to an unexpected behavior on the SCP IP block.

In the Linux kernel, the following vulnerability has been resolved: exec: Fix ToCToU between perm check and set-uid/gid usage When opening a file for exec via do_filp_open(), permission checking is done against the file's metadata at that moment, and on success, a file pointer is passed back. Much later in the execve() code path, the file metadata (specifically mode, uid, and gid) is used to determine if/how to set the uid and gid. However, those values may have changed since the permissions check, meaning the execution may gain unintended privileges. For example, if a file could change permissions from executable and not set-id: ---------x 1 root root 16048 Aug 7 13:16 target to set-id and non-executable: ---S------ 1 root root 16048 Aug 7 13:16 target it is possible to gain root privileges when execution should have been disallowed. While this race condition is rare in real-world scenarios, it has been observed (and proven exploitable) when package managers are updating the setuid bits of installed programs. Such files start with being world-executable but then are adjusted to be group-exec with a set-uid bit. For example, "chmod o-x,u+s target" makes "target" executable only by uid "root" and gid "cdrom", while also becoming setuid-root: -rwxr-xr-x 1 root cdrom 16048 Aug 7 13:16 target becomes: -rwsr-xr-- 1 root cdrom 16048 Aug 7 13:16 target But racing the chmod means users without group "cdrom" membership can get the permission to execute "target" just before the chmod, and when the chmod finishes, the exec reaches brpm_fill_uid(), and performs the setuid to root, violating the expressed authorization of "only cdrom group members can setuid to root". Re-check that we still have execute permissions in case the metadata has changed. It would be better to keep a copy from the perm-check time, but until we can do that refactoring, the least-bad option is to do a full inode_permission() call (under inode lock). It is understood that this is safe against dead-locks, but hardly optimal.

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.

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.

Use-after-free vulnerability in the Transform object implementation in Adobe Flash Player before 18.0.0.343 and 19.x through 21.x before 21.0.0.213 on Windows and OS X and before 11.2.202.616 on Linux allows attackers to execute arbitrary code via a flash.geom.Matrix callback, a different vulnerability than CVE-2016-1011, CVE-2016-1013, CVE-2016-1017, and CVE-2016-1031.

Node.js before 16.6.1, 14.17.5, and 12.22.5 is vulnerable to a use after free attack where an attacker might be able to exploit the memory corruption, to change process behavior.

An issue was discovered in the Linux kernel before 4.20. There is a race condition in smp_task_timedout() and smp_task_done() in drivers/scsi/libsas/sas_expander.c, leading to a use-after-free.

An issue was discovered in the Linux kernel before 4.14.16. There is a use-after-free in net/sctp/socket.c for a held lock after a peel off, aka CID-a0ff660058b8.

A vulnerability, which was classified as critical, was found in Linux Kernel. Affected is the function l2cap_conn_del of the file net/bluetooth/l2cap_core.c of the component Bluetooth. The manipulation leads to use after free. It is recommended to apply a patch to fix this issue. The identifier of this vulnerability is VDB-211944.

Use-after-free vulnerability in Adobe Flash Player before 18.0.0.333 and 19.x through 21.x before 21.0.0.182 on Windows and OS X and before 11.2.202.577 on Linux, Adobe AIR before 21.0.0.176, Adobe AIR SDK before 21.0.0.176, and Adobe AIR SDK & Compiler before 21.0.0.176 allows attackers to execute arbitrary code via unspecified vectors, a different vulnerability than CVE-2016-0987, CVE-2016-0988, CVE-2016-0990, CVE-2016-0991, CVE-2016-0994, CVE-2016-0995, CVE-2016-0996, CVE-2016-0997, CVE-2016-0998, and CVE-2016-1000.

In the Linux kernel through 4.19.6, a local user could exploit a use-after-free in the ALSA driver by supplying a malicious USB Sound device (with zero interfaces) that is mishandled in usb_audio_probe in sound/usb/card.c.

Use-after-free vulnerability in the URLRequest object implementation in Adobe Flash Player before 18.0.0.329 and 19.x and 20.x before 20.0.0.306 on Windows and OS X and before 11.2.202.569 on Linux, Adobe AIR before 20.0.0.260, Adobe AIR SDK before 20.0.0.260, and Adobe AIR SDK & Compiler before 20.0.0.260 allows attackers to execute arbitrary code via a URLLoader.load call, a different vulnerability than CVE-2016-0974, CVE-2016-0975, CVE-2016-0982, CVE-2016-0983, and CVE-2016-0984.

curl 7.75.0 through 7.76.1 suffers from a use-after-free vulnerability resulting in already freed memory being used when a TLS 1.3 session ticket arrives over a connection. A malicious server can use this in rare unfortunate circumstances to potentially reach remote code execution in the client. When libcurl at run-time sets up support for TLS 1.3 session tickets on a connection using OpenSSL, it stores pointers to the transfer in-memory object for later retrieval when a session ticket arrives. If the connection is used by multiple transfers (like with a reused HTTP/1.1 connection or multiplexed HTTP/2 connection) that first transfer object might be freed before the new session is established on that connection and then the function will access a memory buffer that might be freed. When using that memory, libcurl might even call a function pointer in the object, making it possible for a remote code execution if the server could somehow manage to get crafted memory content into the correct place in memory.

Use-after-free vulnerability in mm/mprotect.c in the Linux kernel before 2.6.37-rc2 allows local users to cause a denial of service via vectors involving an mprotect system call.

Use after free vulnerability in Adobe Flash Player Desktop Runtime before 20.0.0.267, Adobe Flash Player Extended Support Release before 18.0.0.324, Adobe Flash Player for Google Chrome before 20.0.0.267, Adobe Flash Player for Microsoft Edge and Internet Explorer 11 before 20.0.0.267, Adobe Flash Player for Internet Explorer 10 and 11 before 20.0.0.267, Adobe Flash Player for Linux before 11.2.202.559, AIR Desktop Runtime before 20.0.0.233, AIR SDK before 20.0.0.233, AIR SDK & Compiler before 20.0.0.233, AIR for Android before 20.0.0.233.

Node.js before 16.6.0, 14.17.4, and 12.22.4 is vulnerable to a use after free attack where an attacker might be able to exploit the memory corruption, to change process behavior.

A use-after-free flaw was found in the Linux kernel's Memory Management subsystem when a user wins two races at the same time with a fail in the mas_prev_slot function. This issue could allow a local user to crash the system.

Use-after-free vulnerability in Adobe Flash Player before 18.0.0.268 and 19.x and 20.x before 20.0.0.228 on Windows and OS X and before 11.2.202.554 on Linux, Adobe AIR before 20.0.0.204, Adobe AIR SDK before 20.0.0.204, and Adobe AIR SDK & Compiler before 20.0.0.204 allows attackers to execute arbitrary code via crafted MPEG-4 data, a different vulnerability than CVE-2015-8048, CVE-2015-8049, CVE-2015-8050, CVE-2015-8055, CVE-2015-8056, CVE-2015-8057, CVE-2015-8058, CVE-2015-8059, CVE-2015-8061, CVE-2015-8062, CVE-2015-8063, CVE-2015-8064, CVE-2015-8065, CVE-2015-8066, CVE-2015-8067, CVE-2015-8068, CVE-2015-8069, CVE-2015-8070, CVE-2015-8071, CVE-2015-8401, CVE-2015-8402, CVE-2015-8403, CVE-2015-8404, CVE-2015-8405, CVE-2015-8406, CVE-2015-8410, CVE-2015-8411, CVE-2015-8412, CVE-2015-8413, CVE-2015-8414, CVE-2015-8420, CVE-2015-8421, CVE-2015-8422, CVE-2015-8423, CVE-2015-8424, CVE-2015-8425, CVE-2015-8426, CVE-2015-8427, CVE-2015-8428, CVE-2015-8429, CVE-2015-8430, CVE-2015-8431, CVE-2015-8432, CVE-2015-8433, CVE-2015-8434, CVE-2015-8435, CVE-2015-8436, CVE-2015-8437, CVE-2015-8441, CVE-2015-8442, CVE-2015-8447, CVE-2015-8448, CVE-2015-8449, CVE-2015-8450, CVE-2015-8452, CVE-2015-8454, CVE-2015-8653, CVE-2015-8821, and CVE-2015-8822.

Use-after-free vulnerability in Adobe Flash Player before 18.0.0.268 and 19.x and 20.x before 20.0.0.228 on Windows and OS X and before 11.2.202.554 on Linux, Adobe AIR before 20.0.0.204, Adobe AIR SDK before 20.0.0.204, and Adobe AIR SDK & Compiler before 20.0.0.204 allows attackers to execute arbitrary code via crafted MPEG-4 data, a different vulnerability than CVE-2015-8048, CVE-2015-8049, CVE-2015-8050, CVE-2015-8055, CVE-2015-8056, CVE-2015-8057, CVE-2015-8058, CVE-2015-8059, CVE-2015-8061, CVE-2015-8062, CVE-2015-8063, CVE-2015-8064, CVE-2015-8065, CVE-2015-8066, CVE-2015-8067, CVE-2015-8068, CVE-2015-8069, CVE-2015-8070, CVE-2015-8071, CVE-2015-8401, CVE-2015-8402, CVE-2015-8403, CVE-2015-8404, CVE-2015-8405, CVE-2015-8406, CVE-2015-8410, CVE-2015-8411, CVE-2015-8412, CVE-2015-8413, CVE-2015-8414, CVE-2015-8420, CVE-2015-8421, CVE-2015-8422, CVE-2015-8423, CVE-2015-8424, CVE-2015-8425, CVE-2015-8426, CVE-2015-8427, CVE-2015-8428, CVE-2015-8429, CVE-2015-8430, CVE-2015-8431, CVE-2015-8432, CVE-2015-8433, CVE-2015-8434, CVE-2015-8435, CVE-2015-8436, CVE-2015-8437, CVE-2015-8441, CVE-2015-8442, CVE-2015-8447, CVE-2015-8448, CVE-2015-8449, CVE-2015-8450, CVE-2015-8452, CVE-2015-8454, CVE-2015-8653, CVE-2015-8655, and CVE-2015-8822.

Use after free in Web Sockets in Google Chrome on Linux prior to 88.0.4324.182 allowed a remote attacker to potentially exploit heap corruption via a crafted HTML page.

In the Linux kernel through 4.19, a use-after-free can occur due to a race condition between fanout_add from setsockopt and bind on an AF_PACKET socket. This issue exists because of the 15fe076edea787807a7cdc168df832544b58eba6 incomplete fix for a race condition. The code mishandles a certain multithreaded case involving a packet_do_bind unregister action followed by a packet_notifier register action. Later, packet_release operates on only one of the two applicable linked lists. The attacker can achieve Program Counter control.

Use-after-free vulnerability in ntpd in NTP 4.2.x before 4.2.8p4, and 4.3.x before 4.3.77 allows remote authenticated users to possibly execute arbitrary code or cause a denial of service (crash) via crafted packets.

Use after free in Network Internals in Google Chrome on Linux prior to 89.0.4389.72 allowed a remote attacker to potentially exploit heap corruption via a crafted HTML page.

Use-after-free vulnerability in Adobe Flash Player before 18.0.0.366 and 19.x through 22.x before 22.0.0.209 on Windows and OS X and before 11.2.202.632 on Linux allows attackers to execute arbitrary code via unspecified vectors, a different vulnerability than CVE-2016-4173, CVE-2016-4174, CVE-2016-4222, CVE-2016-4226, CVE-2016-4227, CVE-2016-4228, CVE-2016-4230, CVE-2016-4231, and CVE-2016-4248.

Use-after-free vulnerability in Adobe Flash Player before 18.0.0.352 and 19.x through 21.x before 21.0.0.242 on Windows and OS X and before 11.2.202.621 on Linux allows attackers to execute arbitrary code via unspecified vectors, a different vulnerability than CVE-2016-1097, CVE-2016-1106, CVE-2016-1107, CVE-2016-1108, CVE-2016-1109, CVE-2016-1110, CVE-2016-4108, and CVE-2016-4110.

The IPv6 stack in the Linux kernel before 4.3.3 mishandles options data, which allows local users to gain privileges or cause a denial of service (use-after-free and system crash) via a crafted sendmsg system call.

The snd_ctl_elem_add function in sound/core/control.c in the ALSA control implementation in the Linux kernel before 3.15.2 does not check authorization for SNDRV_CTL_IOCTL_ELEM_REPLACE commands, which allows local users to remove kernel controls and cause a denial of service (use-after-free and system crash) by leveraging /dev/snd/controlCX access for an ioctl call.

A use-after-free vulnerability in the Linux kernel's netfilter: nf_tables component can be exploited to achieve local privilege escalation. The nft_setelem_catchall_deactivate() function checks whether the catch-all set element is active in the current generation instead of the next generation before freeing it, but only flags it inactive in the next generation, making it possible to free the element multiple times, leading to a double free vulnerability. We recommend upgrading past commit b1db244ffd041a49ecc9618e8feb6b5c1afcdaa7.

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.

Use-after-free vulnerability in the DisplayObject class in the ActionScript 3 (AS3) implementation in Adobe Flash Player 13.x through 13.0.0.302 on Windows and OS X, 14.x through 18.0.0.203 on Windows and OS X, 11.x through 11.2.202.481 on Linux, and 12.x through 18.0.0.204 on Linux Chrome installations allows remote attackers to execute arbitrary code or cause a denial of service (memory corruption) via crafted Flash content that leverages improper handling of the opaqueBackground property, as exploited in the wild in July 2015.