Vulnerabilidades

*** Pendiente de traducción *** In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> vsock/virtio: read virtqueues under worker locks<br /> <br /> Commit bd50c5dc182b ("vsock/virtio: add support for device<br /> suspend/resume") made the *_run flags transition from false to true when<br /> restore installs replacement virtqueues. The RX, TX and event workers<br /> read their virtqueue before locking and checking the corresponding flag,<br /> so a worker delayed across freeze and restore can observe the replacement<br /> queue&amp;#39;s running state while retaining a pointer to the deleted queue.<br /> <br /> Read each virtqueue under its mutex after checking the run flag, keeping<br /> the pointer and state in the same queue generation.

*** Pendiente de traducción *** In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> vxlan: do not arm the ageing timer on a device that is down<br /> <br /> vxlan_changelink() arms vxlan-&gt;age_timer whenever the requested ageing<br /> interval differs from the configured one:<br /> <br /> if (conf.age_interval != vxlan-&gt;cfg.age_interval)<br /> mod_timer(&amp;vxlan-&gt;age_timer, jiffies);<br /> <br /> There is no netif_running() test, so the timer is armed even on a device<br /> that was never brought up. The only synchronous cancel in the driver is<br /> the timer_delete_sync() in vxlan_stop(), which is .ndo_stop.<br /> netif_close_many() drops devices without IFF_UP before<br /> __dev_close_many() runs, so that cancel is skipped for such a device.<br /> <br /> vxlan_setup() sets dev-&gt;needs_free_netdev = true and age_timer is a<br /> member of struct vxlan_dev, so free_netdev() releases the allocation the<br /> timer lives in while it is still queued on a timer_base.<br /> expire_timers() unlinks the entry before it loads timer-&gt;function, so<br /> the timer core writes through the freed object&amp;#39;s list pointers:<br /> <br /> BUG: KASAN: slab-use-after-free in __run_timers+0x208/0x654<br /> Write of size 8 at addr ffff00001adace68 by task true/192<br /> __asan_store8+0x84/0xac<br /> __run_timers+0x208/0x654<br /> run_timer_softirq+0x154/0x18c<br /> Allocated by task 189:<br /> alloc_netdev_mqs+0x64/0x720<br /> rtnl_create_link+0x4ac/0x520<br /> rtnl_newlink+0x758/0xd00<br /> Freed by task 191:<br /> netdev_release+0x40/0x58<br /> netdev_run_todo+0x4a4/0x8c0<br /> rtnl_dellink+0x200/0x4e8<br /> <br /> The rtnl operations involved are netns-scoped, so an unprivileged user<br /> can perform them in a new user and network namespace.<br /> <br /> Arming the timer on a down device never had an effect: vxlan_cleanup()<br /> returns early on !netif_running(), and vxlan_open() arms the timer for<br /> any non-zero interval once the device is brought up. Add the missing<br /> test.<br /> <br /> Discovered by XBOW, triaged by Baul Lee

*** Pendiente de traducción *** In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> xdp: reject clones that overrun skb_shared_info tailroom<br /> <br /> xdpf_clone() clones broadcast copies into a single page and sets<br /> frame_sz to PAGE_SIZE. __xdp_build_skb_from_frame() later treats that<br /> page like a normal XDP frame and expects the usual skb_shared_info<br /> tailroom at the end of the buffer.<br /> <br /> The current check only rejects frames whose linear xdp_frame header,<br /> headroom, and packet data exceed PAGE_SIZE. A source frame backed by a<br /> larger allocation can still satisfy that check while extending into the<br /> clone&amp;#39;s required shared-info area. When such a clone is converted back<br /> into an skb, build_skb_around() places skb_shared_info over live packet<br /> bytes and later writes can corrupt XDP return metadata.<br /> <br /> Reject clones unless their linear area fits inside<br /> SKB_WITH_OVERHEAD(PAGE_SIZE), matching the tailroom requirement already<br /> enforced by the XDP-to-skb conversion path.

*** Pendiente de traducción *** In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> dibs: initialise dibs-&gt;lock in dibs_dev_alloc()<br /> <br /> dibs-&gt;lock is initialised by dibs_dev_add(), but a dibs device can<br /> already take interrupts before that call: ism_probe() runs<br /> ism_dev_init(), and hence request_irq(), before it calls<br /> dibs_dev_add(). No client can have registered a dmb at that point, so<br /> no dmb interrupt can occur, but a GID event interrupt can, and<br /> ism_handle_irq() takes dibs-&gt;lock unconditionally on entry, before it<br /> inspects anything else.<br /> <br /> Initialise the lock in dibs_dev_alloc() instead, so that it is valid as<br /> soon as a driver can publish the device to its interrupt handler.

*** Pendiente de traducción *** In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> KVM: SVM: Serialize accesses to the owner and mirror list with separate lock<br /> <br /> Interaction between KVM_CAP_VM_MOVE_ENC_CONTEXT_FROM and<br /> KVM_CAP_VM_COPY_ENC_CONTEXT_FROM can cause two separate issues:<br /> <br /> - in sev_migrate_from(), when the destination KVM is a mirror, the mirror<br /> entry is moved from the source&amp;#39;s list to the owner&amp;#39;s mirror_vms list,<br /> without holding the owner&amp;#39;s lock unlike other writers of the owner&amp;#39;s<br /> mirror list (sev_vm_copy_enc_context_from(), sev_vm_destroy()).<br /> A concurrent COPY or destroy can race with sev_migrate_from() and<br /> corrupt the list.<br /> <br /> - In sev_vm_destroy(), the *owner* is still active and could receive<br /> concurrently a KVM_CAP_VM_MOVE_ENC_CONTEXT_FROM that causes<br /> sev-&gt;enc_context_owner to change. In this case the incorrect VM<br /> receives kvm_put_kvm().<br /> <br /> The second issue needs particular care because the owner could disappear<br /> altogether (even though the race window is impossibly small) between<br /> reading it and locking it. There is thus no way to perform the checks<br /> under the owner lock without putting struct kvm under SLAB_TYPESAFE_BY_RCU<br /> (which would allow kvm_get_kvm_safe() under RCU critical section).<br /> <br /> It is much simpler to just use a global lock, since the critical<br /> sections are so small and the new lock is always a leaf lock.

*** Pendiente de traducción *** In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> veth: fix skb length accounting after XDP frag adjustment<br /> <br /> veth exposes non-linear skb fragments through an xdp_buff. If an XDP<br /> program adjusts the fragment area, veth_xdp_rcv_skb() copies<br /> xdp_frags_size back to skb-&gt;data_len but leaves skb-&gt;len containing the<br /> old fragment contribution.<br /> <br /> After a fragment shrink, this makes skb_headlen() larger than the actual<br /> linear area. In the reproduced UDP receive path, __skb_datagram_iter()<br /> copied 1024 bytes past the actual linear tail to userspace, starting at<br /> struct skb_shared_info. The copied bytes included the affected skb&amp;#39;s<br /> nr_frags, xdp_frags_size, and a kernel pointer from<br /> skb_shinfo(skb)-&gt;frags[0]. Real packet data was displaced by the same<br /> amount and truncated at the end.<br /> <br /> Subtract the old data_len before replacing it and add the new data_len<br /> afterwards, keeping skb-&gt;len and skb-&gt;data_len synchronized.<br /> <br /> Additionally, bpf_xdp_pull_data() can advance data_end while leaving<br /> frags present. The skb is then still non-linear, so the old<br /> __skb_put(skb, off) triggers SKB_LINEAR_ASSERT().<br /> <br /> Use skb_set_tail_pointer() and update skb-&gt;len explicitly instead,<br /> following bpf_prog_run_generic_xdp(). Unlike __skb_put(),<br /> skb_set_tail_pointer() does not require a linear skb.<br /> <br /> A 60000-byte UDP datagram on a veth pair with MTU 64000 was shortened by<br /> 1024 bytes from its fragment area. Before the fix, all 10 runs produced<br /> corrupted payloads. After the fix, all 10 runs matched the expected<br /> payload exactly. A forced-tailroom reproducer also exercises<br /> bpf_xdp_pull_data() with frags still present; the old code triggers<br /> SKB_LINEAR_ASSERT(), while this fix passes 10/10 runs.

*** Pendiente de traducción *** In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> eventfs: Fix use-after-free in eventfs_remove_rec()<br /> <br /> eventfs_remove_rec() recursively removes the child at the current loop<br /> position. After the recursive call returns, list_for_each_entry() advances<br /> by reading list.next from the removed child.<br /> <br /> If free_ei() drops the final reference, release_ei() reuses the list/rcu<br /> union to queue an SRCU callback. The child may be freed before that read.<br /> The eventfs_mutex serializes list updates, but it does not keep the removed<br /> child alive or prevent the SRCU callback from running.<br /> <br /> Use list_for_each_entry_safe() to save the next sibling before recursively<br /> removing the current child.

*** Pendiente de traducción *** In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> smb: client: Fix use-after-free in cifs_try_adding_channels()<br /> <br /> cifs_try_adding_channels() takes a temporary reference to an interface<br /> before dropping iface_lock. If cifs_ses_add_channel() fails, it drops<br /> that reference and then increments iface-&gt;weight_fulfilled.<br /> <br /> A concurrent interface list refresh can remove the list reference while<br /> channel creation is in progress. In that case, the failure-path<br /> kref_put() releases the last reference and frees iface. Updating<br /> weight_fulfilled afterward then accesses freed memory.<br /> <br /> Increment weight_fulfilled before dropping the temporary reference,<br /> keeping iface alive for the final access.

*** Pendiente de traducción *** In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> tipc: read le-&gt;link under the node lock in tipc_node_link_down()<br /> <br /> tipc_node_link_down() caches the link pointer before taking n-&gt;lock:<br /> <br /> struct tipc_link *l = le-&gt;link; /* unlocked */<br /> <br /> if (!l)<br /> return;<br /> tipc_node_write_lock(n);<br /> if (!tipc_link_is_establishing(l)) { /* deref l */<br /> ...<br /> tipc_link_reset(l); /* write into l */<br /> if (delete) {<br /> kfree(l);<br /> le-&gt;link = NULL;<br /> <br /> The delete=true caller frees that very object under n-&gt;lock, so the lock<br /> does not protect the cached pointer against it:<br /> <br /> - CPU A, delete=false: tipc_rcv() on TIPC_LINK_DOWN_EVT, or the link<br /> supervision timer via tipc_node_timeout(), reads l unlocked and then<br /> dereferences it under n-&gt;lock;<br /> - CPU B, delete=true: netlink TIPC_NL_BEARER_DISABLE -&gt; bearer_disable()<br /> -&gt; tipc_node_delete_links() -&gt; tipc_node_link_down(n, bearer_id, true)<br /> -&gt; kfree(l).<br /> <br /> The link is freed with plain kfree(), not kfree_rcu(), and for UDP bearers<br /> disable_media() only schedules the asynchronous cleanup_bearer() work, so<br /> its synchronize_net() runs after the links are already gone. An in-flight<br /> CPU A that has read l therefore dereferences freed memory once B frees it:<br /> a use-after-free read in tipc_link_is_establishing(), and a use-after-free<br /> write via tipc_link_reset() on the establishing branch.<br /> <br /> The following trace was captured on 7.2.0-rc5-00284-gaf39eb111ce6:<br /> <br /> BUG: KASAN: slab-use-after-free in tipc_link_is_establishing (net/tipc/link.c:285)<br /> Read of size 4 at addr ffff88802e2aa068 by task swapper/2/0<br /> tipc_link_is_establishing (net/tipc/link.c:285)<br /> tipc_node_link_down (net/tipc/node.c:1076)<br /> tipc_node_timeout (net/tipc/node.c:843)<br /> Allocated by task 9549:<br /> tipc_link_create (net/tipc/link.c:490)<br /> tipc_node_check_dest (net/tipc/node.c:1279)<br /> tipc_disc_rcv (net/tipc/discover.c:252)<br /> tipc_udp_recv (net/tipc/udp_media.c:389)<br /> Freed by task 9549:<br /> tipc_node_link_down (net/tipc/node.c:1084)<br /> tipc_node_delete_links (net/tipc/node.c:1320)<br /> bearer_disable (net/tipc/bearer.c:414)<br /> __tipc_nl_bearer_disable (net/tipc/bearer.c:992)<br /> <br /> Move the le-&gt;link read inside tipc_node_write_lock(), so it is serialised<br /> against the kfree() in the delete path. A racing teardown now either has<br /> not run yet, and we see a valid link, or has already run, and we see NULL.

*** Pendiente de traducción *** In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> tls: don&amp;#39;t leave a full plaintext sk_msg ring unpushed<br /> <br /> When the copy path in tls_sw_sendmsg_locked() adds the fragment that fills<br /> the plaintext sk_msg ring, it does not set full_record, so the record is<br /> left full and unpushed. A later splice() then adds to an already full<br /> ring: sk_msg_page_add() has no fullness check of its own, so sg.end wraps<br /> onto sg.start and the ring appears empty. Fragments added after that<br /> overwrite live entries, and sg.size no longer matches what is reachable<br /> between sg.start and sg.end, so pushing the record runs the scatterwalk off<br /> the end of the scatterlist.<br /> <br /> An unprivileged user can trigger this on a loopback TCP socket with the<br /> "tls" ULP attached:<br /> <br /> BUG: kernel NULL pointer dereference, address: 0000000000000008<br /> RIP: 0010:memcpy_from_scatterwalk+0x32/0xc0<br /> Call Trace:<br /> skcipher_walk_next+0x1d1/0x2c0<br /> gcm_encrypt_aesni_avx+0x1e9/0x220<br /> bpf_exec_tx_verdict+0x3bb/0x860<br /> tls_sw_sendmsg+0xa1a/0xca0<br /> __sys_sendto+0x1da/0x1f0<br /> <br /> Set full_record in the copy path when the ring becomes full, and push a<br /> record that is already full on entry to the sendmsg loop.

*** Pendiente de traducción *** In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> tls: rx: restore msg_iter before TLS 1.3 optimistic retry<br /> <br /> tls_decrypt_sg() advances msg-&gt;msg_iter when it maps user pages for<br /> the optimistic TLS 1.3 zero-copy path. If the decrypted record turns<br /> out not to be unpadded application data, tls_decrypt_sw() retries into<br /> a kernel skb, but leaves the iterator advanced.<br /> <br /> The subsequent copy from the skb then writes decrypted bytes again at<br /> a later point in the caller iovecs while recvmsg() reports only the<br /> post-retry length. A TLS peer can trigger this after the receiver<br /> enables TLS_RX_EXPECT_NO_PAD.<br /> <br /> Revert the iterator by the number of bytes consumed by the optimistic<br /> mapping before retrying without zero-copy.<br /> <br /> Add a selftest which sends a TLS 1.3 control record with<br /> TLS_RX_EXPECT_NO_PAD enabled and verifies that recvmsg() does not<br /> overwrite later iovecs beyond the returned length.

*** Pendiente de traducción *** In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> vsock/virtio: avoid refilling the RX queue after teardown<br /> <br /> Commit b917507e5ad9 ("vsock/virtio: stop workers during the .remove()")<br /> made the RX worker jump to its common exit when rx_run is clear. That<br /> exit still refills the RX queue when the buffer count is low, so work<br /> queued across virtio_vsock_vqs_del() can add buffers after the virtqueues<br /> have been deleted.<br /> <br /> BUG: KASAN: slab-use-after-free in virtqueue_add_sgs<br /> Read of size 4 by task kworker/0:1<br /> Workqueue: virtio_vsock virtio_transport_rx_work<br /> Call Trace:<br /> virtqueue_add_sgs (drivers/virtio/virtio_ring.c:2796)<br /> virtio_vsock_rx_fill (net/vmw_vsock/virtio_transport.c:332)<br /> virtio_transport_rx_work (net/vmw_vsock/virtio_transport.c:701)<br /> process_one_work (kernel/workqueue.c:3314)<br /> worker_thread (kernel/workqueue.c:3478)<br /> kthread (kernel/kthread.c:436)<br /> ret_from_fork (arch/x86/kernel/process.c:158)<br /> ret_from_fork_asm (arch/x86/entry/entry_64.S:245)<br /> ...<br /> Freed by task 141:<br /> kfree (mm/slub.c:6566)<br /> vp_del_vq (drivers/virtio/virtio_pci_common.c:259)<br /> vp_del_vqs (drivers/virtio/virtio_pci_common.c:285)<br /> virtio_vsock_freeze (net/vmw_vsock/virtio_transport.c:912)<br /> virtio_device_freeze (drivers/virtio/virtio.c:658)<br /> virtio_pci_freeze (drivers/virtio/virtio_pci_common.c:601)<br /> pci_pm_freeze (drivers/pci/pci-driver.c:1098)<br /> device_suspend (drivers/base/power/main.c:1968)<br /> Kernel panic - not syncing: KASAN: panic_on_warn set ...<br /> <br /> Jump to a no-refill exit when rx_run is clear, leaving the normal exit<br /> to replenish a running queue.