Sicherheitslücken in linux-kvm · Seite 188

__legitimize_mnt(): check for MNT_SYNC_UMOUNT should be under mount_lock

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.

smb: client: Fix use-after-free in cifs_fill_dirent

In the Linux kernel, the following vulnerability has been resolved: smb: client: Fix use-after-free in cifs_fill_dirent There is a race condition in the readdir concurrency process, which may access the rsp buffer after it has been released, triggering the following KASAN warning. ================================================================== BUG: KASAN: slab-use-after-free in cifs_fill_dirent+0xb03/0xb60 [cifs] Read of size 4 at addr ffff8880099b819c by task a.out/342975 CPU: 2 UID: 0 PID: 342975 Comm: a.out Not tainted 6.15.0-rc6+ #240 PREEMPT(full) Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.1-2.fc37 04/01

serial: mctrl_gpio: split disable_ms into sync and no_sync APIs

In the Linux kernel, the following vulnerability has been resolved: serial: mctrl_gpio: split disable_ms into sync and no_sync APIs The following splat has been observed on a SAMA5D27 platform using atmel_serial: BUG: sleeping function called from invalid context at kernel/irq/manage.c:738 in_atomic(): 1, irqs_disabled(): 128, non_block: 0, pid: 27, name: kworker/u5:0 preempt_count: 1, expected: 0 INFO: lockdep is turned off. irq event stamp: 0 hardirqs last enabled at (0): [<00000000>] 0x0 hardirqs last disabled at (0): [<c01588f0>] copy_process+0x1c4c/0x7bec softirqs last enabled at (0): [<c0158944>] copy_process+0x1ca0/0x7bec softirqs

vxlan: Annotate FDB data races

In the Linux kernel, the following vulnerability has been resolved: vxlan: Annotate FDB data races The 'used' and 'updated' fields in the FDB entry structure can be accessed concurrently by multiple threads, leading to reports such as [1]. Can be reproduced using [2]. Suppress these reports by annotating these accesses using READ_ONCE() / WRITE_ONCE(). [1] BUG: KCSAN: data-race in vxlan_xmit / vxlan_xmit write to 0xffff942604d263a8 of 8 bytes by task 286 on cpu 0: vxlan_xmit+0xb29/0x2380 dev_hard_start_xmit+0x84/0x2f0 __dev_queue_xmit+0x45a/0x1650 packet_xmit+0x100/0x150 packet_sendmsg+0x2114/0x2ac0 __sys_sendto+0x318/0x330 __x64_

btrfs: correct the order of prelim_ref arguments in btrfs__prelim_ref

In the Linux kernel, the following vulnerability has been resolved: btrfs: correct the order of prelim_ref arguments in btrfs__prelim_ref btrfs_prelim_ref() calls the old and new reference variables in the incorrect order. This causes a NULL pointer dereference because oldref is passed as NULL to trace_btrfs_prelim_ref_insert(). Note, trace_btrfs_prelim_ref_insert() is being called with newref as oldref (and oldref as NULL) on purpose in order to print out the values of newref. To reproduce: echo 1 > /sys/kernel/debug/tracing/events/btrfs/btrfs_prelim_ref_insert/enable Perform some writeback operations. Backtrace: BUG: kernel NULL point

RDMA/rxe: Fix slab-use-after-free Read in rxe_queue_cleanup bug

In the Linux kernel, the following vulnerability has been resolved: RDMA/rxe: Fix slab-use-after-free Read in rxe_queue_cleanup bug Call Trace: <TASK> __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x7d/0xa0 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xcf/0x610 mm/kasan/report.c:489 kasan_report+0xb5/0xe0 mm/kasan/report.c:602 rxe_queue_cleanup+0xd0/0xe0 drivers/infiniband/sw/rxe/rxe_queue.c:195 rxe_cq_cleanup+0x3f/0x50 drivers/infiniband/sw/rxe/rxe_cq.c:132 __rxe_cleanup+0x168/0x300 drivers/infiniband/sw/rxe/rxe_pool.c:232 rxe_create_cq+0x22e/0x3a0 drivers/infiniband/sw/rx

nfs: handle failure of nfs_get_lock_context in unlock path

In the Linux kernel, the following vulnerability has been resolved: nfs: handle failure of nfs_get_lock_context in unlock path When memory is insufficient, the allocation of nfs_lock_context in nfs_get_lock_context() fails and returns -ENOMEM. If we mistakenly treat an nfs4_unlockdata structure (whose l_ctx member has been set to -ENOMEM) as valid and proceed to execute rpc_run_task(), this will trigger a NULL pointer dereference in nfs4_locku_prepare. For example: BUG: kernel NULL pointer dereference, address: 000000000000000c PGD 0 P4D 0 Oops: Oops: 0000 [#1] SMP PTI CPU: 15 UID: 0 PID: 12 Comm: kworker/u64:0 Not tainted 6.15.0-rc2-dirty

can: bcm: add locking for bcm_op runtime updates

In the Linux kernel, the following vulnerability has been resolved: can: bcm: add locking for bcm_op runtime updates The CAN broadcast manager (CAN BCM) can send a sequence of CAN frames via hrtimer. The content and also the length of the sequence can be changed resp reduced at runtime where the 'currframe' counter is then set to zero. Although this appeared to be a safe operation the updates of 'currframe' can be triggered from user space and hrtimer context in bcm_can_tx(). Anderson Nascimento created a proof of concept that triggered a KASAN slab-out-of-bounds read access which can be prevented with a spin_lock_bh. At the rework of bcm

sch_hfsc: Fix qlen accounting bug when using peek in hfsc_enqueue()

In the Linux kernel, the following vulnerability has been resolved: sch_hfsc: Fix qlen accounting bug when using peek in hfsc_enqueue() When enqueuing the first packet to an HFSC class, hfsc_enqueue() calls the child qdisc's peek() operation before incrementing sch->q.qlen and sch->qstats.backlog. If the child qdisc uses qdisc_peek_dequeued(), this may trigger an immediate dequeue and potential packet drop. In such cases, qdisc_tree_reduce_backlog() is called, but the HFSC qdisc's qlen and backlog have not yet been updated, leading to inconsistent queue accounting. This can leave an empty HFSC class in the active list, causing further conse

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openvswitch: Fix unsafe attribute parsing in output_userspace()

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.

module: ensure that kobject_put() is safe for module type kobjects

In the Linux kernel, the following vulnerability has been resolved: module: ensure that kobject_put() is safe for module type kobjects In 'lookup_or_create_module_kobject()', an internal kobject is created using 'module_ktype'. So call to 'kobject_put()' on error handling path causes an attempt to use an uninitialized completion pointer in 'module_kobject_release()'. In this scenario, we just want to release kobject without an extra synchronization required for a regular module unloading process, so adding an extra check whether 'complete()' is actually required makes 'kobject_put()' safe.

net_sched: Flush gso_skb list too during ->change()

In the Linux kernel, the following vulnerability has been resolved: net_sched: Flush gso_skb list too during ->change() Previously, when reducing a qdisc's limit via the ->change() operation, only the main skb queue was trimmed, potentially leaving packets in the gso_skb list. This could result in NULL pointer dereference when we only check sch->limit against sch->q.qlen. This patch introduces a new helper, qdisc_dequeue_internal(), which ensures both the gso_skb list and the main queue are properly flushed when trimming excess packets. All relevant qdiscs (codel, fq, fq_codel, fq_pie, hhf, pie) are updated to use this helper in their ->ch

CVE-2025-27558

IEEE P802.11-REVme D1.1 through D7.0 allows FragAttacks against mesh networks. In mesh networks using Wi-Fi Protected Access (WPA, WPA2, or WPA3) or Wired Equivalent Privacy (WEP), an adversary can exploit this vulnerability to inject arbitrary frames towards devices that support receiving non-SSP A-MSDU frames. NOTE: this issue exists because of an incorrect fix for CVE-2020-24588. P802.11-REVme, as of early 2025, is a planned release of the 802.11 standard.

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parisc: Fix double SIGFPE crash

In the Linux kernel, the following vulnerability has been resolved: parisc: Fix double SIGFPE crash Camm noticed that on parisc a SIGFPE exception will crash an application with a second SIGFPE in the signal handler. Dave analyzed it, and it happens because glibc uses a double-word floating-point store to atomically update function descriptors. As a result of lazy binding, we hit a floating-point store in fpe_func almost immediately. When the T bit is set, an assist exception trap occurs when when the co-processor encounters *any* floating-point instruction except for a double store of register %fr0. The latter cancels all pending traps.

wifi: brcm80211: fmac: Add error handling for brcmf_usb_dl_writeimage()

In the Linux kernel, the following vulnerability has been resolved: wifi: brcm80211: fmac: Add error handling for brcmf_usb_dl_writeimage() The function brcmf_usb_dl_writeimage() calls the function brcmf_usb_dl_cmd() but dose not check its return value. The 'state.state' and the 'state.bytes' are uninitialized if the function brcmf_usb_dl_cmd() fails. It is dangerous to use uninitialized variables in the conditions. Add error handling for brcmf_usb_dl_cmd() to jump to error handling path if the brcmf_usb_dl_cmd() fails and the 'state.state' and the 'state.bytes' are uninitialized. Improve the error message to report more detailed error in

UBUNTU-CVE-2025-37976

Rejected reason: This CVE ID has been rejected or withdrawn by its CVE Numbering Authority.

net: phy: leds: fix memory leak

In the Linux kernel, the following vulnerability has been resolved: net: phy: leds: fix memory leak A network restart test on a router led to an out-of-memory condition, which was traced to a memory leak in the PHY LED trigger code. The root cause is misuse of the devm API. The registration function (phy_led_triggers_register) is called from phy_attach_direct, not phy_probe, and the unregister function (phy_led_triggers_unregister) is called from phy_detach, not phy_remove. This means the register and unregister functions can be called multiple times for the same PHY device, but devm-allocated memory is not freed until the driver is unboun

qibfs: fix _another_ leak

In the Linux kernel, the following vulnerability has been resolved: qibfs: fix _another_ leak failure to allocate inode => leaked dentry... this one had been there since the initial merge; to be fair, if we are that far OOM, the odds of failing at that particular allocation are low...

wifi: wl1251: fix memory leak in wl1251_tx_work

In the Linux kernel, the following vulnerability has been resolved: wifi: wl1251: fix memory leak in wl1251_tx_work The skb dequeued from tx_queue is lost when wl1251_ps_elp_wakeup fails with a -ETIMEDOUT error. Fix that by queueing the skb back to tx_queue.

block: fix resource leak in blk_register_queue() error path

In the Linux kernel, the following vulnerability has been resolved: block: fix resource leak in blk_register_queue() error path When registering a queue fails after blk_mq_sysfs_register() is successful but the function later encounters an error, we need to clean up the blk_mq_sysfs resources. Add the missing blk_mq_sysfs_unregister() call in the error path to properly clean up these resources and prevent a memory leak.