Vulnerabilidades do Debian Debian Linux

In the Linux kernel, the following vulnerability has been resolved: espintcp: remove encap socket caching to avoid reference leak The current scheme for caching the encap socket can lead to reference leaks when we try to delete the netns. The reference chain is: xfrm_state -> enacp_sk -> netns Since the encap socket is a userspace socket, it holds a reference on the netns. If we delete the espintcp state (through flush or individual delete) before removing the netns, the reference on the socket is dropped and the netns is correctly deleted. Otherwise, the netns may not be reachable anymore (if all processes within the ns have terminated), so we cannot delete the xfrm state to drop its reference on the socket. This patch results in a small (~2% in my tests) performance regression. A GC-type mechanism could be added for the socket cache, to clear references if the state hasn't been used "recently", but it's a lot more complex than just not caching the socket.

In the Linux kernel, the following vulnerability has been resolved: dma-buf: insert memory barrier before updating num_fences smp_store_mb() inserts memory barrier after storing operation. It is different with what the comment is originally aiming so Null pointer dereference can be happened if memory update is reordered.

In the Linux kernel, the following vulnerability has been resolved: mm/hugetlb: unshare page tables during VMA split, not before Currently, __split_vma() triggers hugetlb page table unsharing through vm_ops->may_split(). This happens before the VMA lock and rmap locks are taken - which is too early, it allows racing VMA-locked page faults in our process and racing rmap walks from other processes to cause page tables to be shared again before we actually perform the split. Fix it by explicitly calling into the hugetlb unshare logic from __split_vma() in the same place where THP splitting also happens. At that point, both the VMA and the rmap(s) are write-locked. An annoying detail is that we can now call into the helper hugetlb_unshare_pmds() from two different locking contexts: 1. from hugetlb_split(), holding: - mmap lock (exclusively) - VMA lock - file rmap lock (exclusively) 2. hugetlb_unshare_all_pmds(), which I think is designed to be able to call us with only the mmap lock held (in shared mode), but currently only runs while holding mmap lock (exclusively) and VMA lock Backporting note: This commit fixes a racy protection that was introduced in commit b30c14cd6102 ("hugetlb: unshare some PMDs when splitting VMAs"); that commit claimed to fix an issue introduced in 5.13, but it should actually also go all the way back. [jannh@google.com: v2]

In the Linux kernel, the following vulnerability has been resolved: net_sched: prio: fix a race in prio_tune() Gerrard Tai reported a race condition in PRIO, whenever SFQ perturb timer fires at the wrong time. The race is as follows: CPU 0 CPU 1 [1]: lock root [2]: qdisc_tree_flush_backlog() [3]: unlock root | | [5]: lock root | [6]: rehash | [7]: qdisc_tree_reduce_backlog() | [4]: qdisc_put() This can be abused to underflow a parent's qlen. Calling qdisc_purge_queue() instead of qdisc_tree_flush_backlog() should fix the race, because all packets will be purged from the qdisc before releasing the lock.

In the Linux kernel, the following vulnerability has been resolved: ALSA: pcm: Fix race of buffer access at PCM OSS layer The PCM OSS layer tries to clear the buffer with the silence data at initialization (or reconfiguration) of a stream with the explicit call of snd_pcm_format_set_silence() with runtime->dma_area. But this may lead to a UAF because the accessed runtime->dma_area might be freed concurrently, as it's performed outside the PCM ops. For avoiding it, move the code into the PCM core and perform it inside the buffer access lock, so that it won't be changed during the operation.

In the Linux kernel, the following vulnerability has been resolved: scsi: target: iscsi: Fix timeout on deleted connection NOPIN response timer may expire on a deleted connection and crash with such logs: Did not receive response to NOPIN on CID: 0, failing connection for I_T Nexus (null),i,0x00023d000125,iqn.2017-01.com.iscsi.target,t,0x3d BUG: Kernel NULL pointer dereference on read at 0x00000000 NIP strlcpy+0x8/0xb0 LR iscsit_fill_cxn_timeout_err_stats+0x5c/0xc0 [iscsi_target_mod] Call Trace: iscsit_handle_nopin_response_timeout+0xfc/0x120 [iscsi_target_mod] call_timer_fn+0x58/0x1f0 run_timer_softirq+0x740/0x860 __do_softirq+0x16c/0x420 irq_exit+0x188/0x1c0 timer_interrupt+0x184/0x410 That is because nopin response timer may be re-started on nopin timer expiration. Stop nopin timer before stopping the nopin response timer to be sure that no one of them will be re-started.

In the Linux kernel, the following vulnerability has been resolved: __legitimize_mnt(): check for MNT_SYNC_UMOUNT should be under mount_lock ... or we risk stealing final mntput from sync umount - raising mnt_count after umount(2) has verified that victim is not busy, but before it has set MNT_SYNC_UMOUNT; in that case __legitimize_mnt() doesn't see that it's safe to quietly undo mnt_count increment and leaves dropping the reference to caller, where it'll be a full-blown mntput(). Check under mount_lock is needed; leaving the current one done before taking that makes no sense - it's nowhere near common enough to bother with.

In the Linux kernel, the following vulnerability has been resolved: nvmet-tcp: don't restore null sk_state_change queue->state_change is set as part of nvmet_tcp_set_queue_sock(), but if the TCP connection isn't established when nvmet_tcp_set_queue_sock() is called then queue->state_change isn't set and sock->sk->sk_state_change isn't replaced. As such we don't need to restore sock->sk->sk_state_change if queue->state_change is NULL. This avoids NULL pointer dereferences such as this: [ 286.462026][ C0] BUG: kernel NULL pointer dereference, address: 0000000000000000 [ 286.462814][ C0] #PF: supervisor instruction fetch in kernel mode [ 286.463796][ C0] #PF: error_code(0x0010) - not-present page [ 286.464392][ C0] PGD 8000000140620067 P4D 8000000140620067 PUD 114201067 PMD 0 [ 286.465086][ C0] Oops: Oops: 0010 [#1] SMP KASAN PTI [ 286.465559][ C0] CPU: 0 UID: 0 PID: 1628 Comm: nvme Not tainted 6.15.0-rc2+ #11 PREEMPT(voluntary) [ 286.466393][ C0] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-3.fc41 04/01/2014 [ 286.467147][ C0] RIP: 0010:0x0 [ 286.467420][ C0] Code: Unable to access opcode bytes at 0xffffffffffffffd6. [ 286.467977][ C0] RSP: 0018:ffff8883ae008580 EFLAGS: 00010246 [ 286.468425][ C0] RAX: 0000000000000000 RBX: ffff88813fd34100 RCX: ffffffffa386cc43 [ 286.469019][ C0] RDX: 1ffff11027fa68b6 RSI: 0000000000000008 RDI: ffff88813fd34100 [ 286.469545][ C0] RBP: ffff88813fd34160 R08: 0000000000000000 R09: ffffed1027fa682c [ 286.470072][ C0] R10: ffff88813fd34167 R11: 0000000000000000 R12: ffff88813fd344c3 [ 286.470585][ C0] R13: ffff88813fd34112 R14: ffff88813fd34aec R15: ffff888132cdd268 [ 286.471070][ C0] FS: 00007fe3c04c7d80(0000) GS:ffff88840743f000(0000) knlGS:0000000000000000 [ 286.471644][ C0] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 286.472543][ C0] CR2: ffffffffffffffd6 CR3: 000000012daca000 CR4: 00000000000006f0 [ 286.473500][ C0] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 286.474467][ C0] DR3: 0000000000000000 DR6: 00000000ffff07f0 DR7: 0000000000000400 [ 286.475453][ C0] Call Trace: [ 286.476102][ C0] <IRQ> [ 286.476719][ C0] tcp_fin+0x2bb/0x440 [ 286.477429][ C0] tcp_data_queue+0x190f/0x4e60 [ 286.478174][ C0] ? __build_skb_around+0x234/0x330 [ 286.478940][ C0] ? rcu_is_watching+0x11/0xb0 [ 286.479659][ C0] ? __pfx_tcp_data_queue+0x10/0x10 [ 286.480431][ C0] ? tcp_try_undo_loss+0x640/0x6c0 [ 286.481196][ C0] ? seqcount_lockdep_reader_access.constprop.0+0x82/0x90 [ 286.482046][ C0] ? kvm_clock_get_cycles+0x14/0x30 [ 286.482769][ C0] ? ktime_get+0x66/0x150 [ 286.483433][ C0] ? rcu_is_watching+0x11/0xb0 [ 286.484146][ C0] tcp_rcv_established+0x6e4/0x2050 [ 286.484857][ C0] ? rcu_is_watching+0x11/0xb0 [ 286.485523][ C0] ? ipv4_dst_check+0x160/0x2b0 [ 286.486203][ C0] ? __pfx_tcp_rcv_established+0x10/0x10 [ 286.486917][ C0] ? lock_release+0x217/0x2c0 [ 286.487595][ C0] tcp_v4_do_rcv+0x4d6/0x9b0 [ 286.488279][ C0] tcp_v4_rcv+0x2af8/0x3e30 [ 286.488904][ C0] ? raw_local_deliver+0x51b/0xad0 [ 286.489551][ C0] ? rcu_is_watching+0x11/0xb0 [ 286.490198][ C0] ? __pfx_tcp_v4_rcv+0x10/0x10 [ 286.490813][ C0] ? __pfx_raw_local_deliver+0x10/0x10 [ 286.491487][ C0] ? __pfx_nf_confirm+0x10/0x10 [nf_conntrack] [ 286.492275][ C0] ? rcu_is_watching+0x11/0xb0 [ 286.492900][ C0] ip_protocol_deliver_rcu+0x8f/0x370 [ 286.493579][ C0] ip_local_deliver_finish+0x297/0x420 [ 286.494268][ C0] ip_local_deliver+0x168/0x430 [ 286.494867][ C0] ? __pfx_ip_local_deliver+0x10/0x10 [ 286.495498][ C0] ? __pfx_ip_local_deliver_finish+0x10/0x10 [ 286.496204][ C0] ? ip_rcv_finish_core+0x19a/0x1f20 [ 286.496806][ C0] ? lock_release+0x217/0x2c0 [ 286.497414][ C0] ip_rcv+0x455/0x6e0 [ 286.497945][ C0] ? __pfx_ip_rcv+0x10/0x10 [ ---truncated---

In the Linux kernel, the following vulnerability has been resolved: net_sched: hfsc: Address reentrant enqueue adding class to eltree twice Savino says: "We are writing to report that this recent patch (141d34391abbb315d68556b7c67ad97885407547) [1] can be bypassed, and a UAF can still occur when HFSC is utilized with NETEM. The patch only checks the cl->cl_nactive field to determine whether it is the first insertion or not [2], but this field is only incremented by init_vf [3]. By using HFSC_RSC (which uses init_ed) [4], it is possible to bypass the check and insert the class twice in the eltree. Under normal conditions, this would lead to an infinite loop in hfsc_dequeue for the reasons we already explained in this report [5]. However, if TBF is added as root qdisc and it is configured with a very low rate, it can be utilized to prevent packets from being dequeued. This behavior can be exploited to perform subsequent insertions in the HFSC eltree and cause a UAF." To fix both the UAF and the infinite loop, with netem as an hfsc child, check explicitly in hfsc_enqueue whether the class is already in the eltree whenever the HFSC_RSC flag is set. [1] https://web.git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=141d34391abbb315d68556b7c67ad97885407547 [2] https://elixir.bootlin.com/linux/v6.15-rc5/source/net/sched/sch_hfsc.c#L1572 [3] https://elixir.bootlin.com/linux/v6.15-rc5/source/net/sched/sch_hfsc.c#L677 [4] https://elixir.bootlin.com/linux/v6.15-rc5/source/net/sched/sch_hfsc.c#L1574 [5] https://lore.kernel.org/netdev/8DuRWwfqjoRDLDmBMlIfbrsZg9Gx50DHJc1ilxsEBNe2D6NMoigR_eIRIG0LOjMc3r10nUUZtArXx4oZBIdUfZQrwjcQhdinnMis_0G7VEk=@willsroot.io/T/#u

In the Linux kernel, the following vulnerability has been resolved: openvswitch: Fix unsafe attribute parsing in output_userspace() This patch replaces the manual Netlink attribute iteration in output_userspace() with nla_for_each_nested(), which ensures that only well-formed attributes are processed.

In the Linux kernel, the following vulnerability has been resolved: netfilter: ipset: fix region locking in hash types Region locking introduced in v5.6-rc4 contained three macros to handle the region locks: ahash_bucket_start(), ahash_bucket_end() which gave back the start and end hash bucket values belonging to a given region lock and ahash_region() which should give back the region lock belonging to a given hash bucket. The latter was incorrect which can lead to a race condition between the garbage collector and adding new elements when a hash type of set is defined with timeouts.

In the Linux kernel, the following vulnerability has been resolved: Input: mtk-pmic-keys - fix possible null pointer dereference In mtk_pmic_keys_probe, the regs parameter is only set if the button is parsed in the device tree. However, on hardware where the button is left floating, that node will most likely be removed not to enable that input. In that case the code will try to dereference a null pointer. Let's use the regs struct instead as it is defined for all supported platforms. Note that it is ok setting the key reg even if that latter is disabled as the interrupt won't be enabled anyway.

In the Linux kernel, the following vulnerability has been resolved: x86/mm: Eliminate window where TLB flushes may be inadvertently skipped tl;dr: There is a window in the mm switching code where the new CR3 is set and the CPU should be getting TLB flushes for the new mm. But should_flush_tlb() has a bug and suppresses the flush. Fix it by widening the window where should_flush_tlb() sends an IPI. Long Version: === History === There were a few things leading up to this. First, updating mm_cpumask() was observed to be too expensive, so it was made lazier. But being lazy caused too many unnecessary IPIs to CPUs due to the now-lazy mm_cpumask(). So code was added to cull mm_cpumask() periodically[2]. But that culling was a bit too aggressive and skipped sending TLB flushes to CPUs that need them. So here we are again. === Problem === The too-aggressive code in should_flush_tlb() strikes in this window: // Turn on IPIs for this CPU/mm combination, but only // if should_flush_tlb() agrees: cpumask_set_cpu(cpu, mm_cpumask(next)); next_tlb_gen = atomic64_read(&next->context.tlb_gen); choose_new_asid(next, next_tlb_gen, &new_asid, &need_flush); load_new_mm_cr3(need_flush); // ^ After 'need_flush' is set to false, IPIs *MUST* // be sent to this CPU and not be ignored. this_cpu_write(cpu_tlbstate.loaded_mm, next); // ^ Not until this point does should_flush_tlb() // become true! should_flush_tlb() will suppress TLB flushes between load_new_mm_cr3() and writing to 'loaded_mm', which is a window where they should not be suppressed. Whoops. === Solution === Thankfully, the fuzzy "just about to write CR3" window is already marked with loaded_mm==LOADED_MM_SWITCHING. Simply checking for that state in should_flush_tlb() is sufficient to ensure that the CPU is targeted with an IPI. This will cause more TLB flush IPIs. But the window is relatively small and I do not expect this to cause any kind of measurable performance impact. Update the comment where LOADED_MM_SWITCHING is written since it grew yet another user. Peter Z also raised a concern that should_flush_tlb() might not observe 'loaded_mm' and 'is_lazy' in the same order that switch_mm_irqs_off() writes them. Add a barrier to ensure that they are observed in the order they are written.

In the Linux kernel, the following vulnerability has been resolved: bpf: Scrub packet on bpf_redirect_peer When bpf_redirect_peer is used to redirect packets to a device in another network namespace, the skb isn't scrubbed. That can lead skb information from one namespace to be "misused" in another namespace. As one example, this is causing Cilium to drop traffic when using bpf_redirect_peer to redirect packets that just went through IPsec decryption to a container namespace. The following pwru trace shows (1) the packet path from the host's XFRM layer to the container's XFRM layer where it's dropped and (2) the number of active skb extensions at each function. NETNS MARK IFACE TUPLE FUNC 4026533547 d00 eth0 10.244.3.124:35473->10.244.2.158:53 xfrm_rcv_cb .active_extensions = (__u8)2, 4026533547 d00 eth0 10.244.3.124:35473->10.244.2.158:53 xfrm4_rcv_cb .active_extensions = (__u8)2, 4026533547 d00 eth0 10.244.3.124:35473->10.244.2.158:53 gro_cells_receive .active_extensions = (__u8)2, [...] 4026533547 0 eth0 10.244.3.124:35473->10.244.2.158:53 skb_do_redirect .active_extensions = (__u8)2, 4026534999 0 eth0 10.244.3.124:35473->10.244.2.158:53 ip_rcv .active_extensions = (__u8)2, 4026534999 0 eth0 10.244.3.124:35473->10.244.2.158:53 ip_rcv_core .active_extensions = (__u8)2, [...] 4026534999 0 eth0 10.244.3.124:35473->10.244.2.158:53 udp_queue_rcv_one_skb .active_extensions = (__u8)2, 4026534999 0 eth0 10.244.3.124:35473->10.244.2.158:53 __xfrm_policy_check .active_extensions = (__u8)2, 4026534999 0 eth0 10.244.3.124:35473->10.244.2.158:53 __xfrm_decode_session .active_extensions = (__u8)2, 4026534999 0 eth0 10.244.3.124:35473->10.244.2.158:53 security_xfrm_decode_session .active_extensions = (__u8)2, 4026534999 0 eth0 10.244.3.124:35473->10.244.2.158:53 kfree_skb_reason(SKB_DROP_REASON_XFRM_POLICY) .active_extensions = (__u8)2, In this case, there are no XFRM policies in the container's network namespace so the drop is unexpected. When we decrypt the IPsec packet, the XFRM state used for decryption is set in the skb extensions. This information is preserved across the netns switch. When we reach the XFRM policy check in the container's netns, __xfrm_policy_check drops the packet with LINUX_MIB_XFRMINNOPOLS because a (container-side) XFRM policy can't be found that matches the (host-side) XFRM state used for decryption. This patch fixes this by scrubbing the packet when using bpf_redirect_peer, as is done on typical netns switches via veth devices except skb->mark and skb->tstamp are not zeroed.

In the Linux kernel, the following vulnerability has been resolved: xenbus: Use kref to track req lifetime Marek reported seeing a NULL pointer fault in the xenbus_thread callstack: BUG: kernel NULL pointer dereference, address: 0000000000000000 RIP: e030:__wake_up_common+0x4c/0x180 Call Trace: <TASK> __wake_up_common_lock+0x82/0xd0 process_msg+0x18e/0x2f0 xenbus_thread+0x165/0x1c0 process_msg+0x18e is req->cb(req). req->cb is set to xs_wake_up(), a thin wrapper around wake_up(), or xenbus_dev_queue_reply(). It seems like it was xs_wake_up() in this case. It seems like req may have woken up the xs_wait_for_reply(), which kfree()ed the req. When xenbus_thread resumes, it faults on the zero-ed data. Linux Device Drivers 2nd edition states: "Normally, a wake_up call can cause an immediate reschedule to happen, meaning that other processes might run before wake_up returns." ... which would match the behaviour observed. Change to keeping two krefs on each request. One for the caller, and one for xenbus_thread. Each will kref_put() when finished, and the last will free it. This use of kref matches the description in Documentation/core-api/kref.rst

In the Linux kernel, the following vulnerability has been resolved: tracing: Verify event formats that have "%*p.." The trace event verifier checks the formats of trace events to make sure that they do not point at memory that is not in the trace event itself or in data that will never be freed. If an event references data that was allocated when the event triggered and that same data is freed before the event is read, then the kernel can crash by reading freed memory. The verifier runs at boot up (or module load) and scans the print formats of the events and checks their arguments to make sure that dereferenced pointers are safe. If the format uses "%*p.." the verifier will ignore it, and that could be dangerous. Cover this case as well. Also add to the sample code a use case of "%*pbl".