In the Linux kernel, the following vulnerability has been resolved:
NFSD: Prevent NULL dereference in nfsd4_process_cb_update()
@ses is initialized to NULL. If __nfsd4_find_backchannel() finds no
available backchannel session, setup_callback_client() will try to
dereference @ses and segfault.
In the Linux kernel, the following vulnerability has been resolved:
s390/iucv: MSG_PEEK causes memory leak in iucv_sock_destruct()
Passing MSG_PEEK flag to skb_recv_datagram() increments skb refcount
(skb->users) and iucv_sock_recvmsg() does not decrement skb refcount
at exit.
This results in skb memory leak in skb_queue_purge() and WARN_ON in
iucv_sock_destruct() during socket close. To fix this decrease
skb refcount by one if MSG_PEEK is set in order to prevent memory
leak and WARN_ON.
WARNING: CPU: 2 PID: 6292 at net/iucv/af_iucv.c:286 iucv_sock_destruct+0x144/0x1a0 [af_iucv]
CPU: 2 PID: 6292 Comm: afiucv_test_msg Kdump: loaded Tainted: G W 6.10.0-rc7 #1
Hardware name: IBM 3931 A01 704 (z/VM 7.3.0)
Call Trace:
[<001587c682c4aa98>] iucv_sock_destruct+0x148/0x1a0 [af_iucv]
[<001587c682c4a9d0>] iucv_sock_destruct+0x80/0x1a0 [af_iucv]
[<001587c704117a32>] __sk_destruct+0x52/0x550
[<001587c704104a54>] __sock_release+0xa4/0x230
[<001587c704104c0c>] sock_close+0x2c/0x40
[<001587c702c5f5a8>] __fput+0x2e8/0x970
[<001587c7024148c4>] task_work_run+0x1c4/0x2c0
[<001587c7023b0716>] do_exit+0x996/0x1050
[<001587c7023b13aa>] do_group_exit+0x13a/0x360
[<001587c7023b1626>] __s390x_sys_exit_group+0x56/0x60
[<001587c7022bccca>] do_syscall+0x27a/0x380
[<001587c7049a6a0c>] __do_syscall+0x9c/0x160
[<001587c7049ce8a8>] system_call+0x70/0x98
Last Breaking-Event-Address:
[<001587c682c4a9d4>] iucv_sock_destruct+0x84/0x1a0 [af_iucv]
In the Linux kernel, the following vulnerability has been resolved:
PCI: Fix use-after-free of slot->bus on hot remove
Dennis reports a boot crash on recent Lenovo laptops with a USB4 dock.
Since commit 0fc70886569c ("thunderbolt: Reset USB4 v2 host router") and
commit 59a54c5f3dbd ("thunderbolt: Reset topology created by the boot
firmware"), USB4 v2 and v1 Host Routers are reset on probe of the
thunderbolt driver.
The reset clears the Presence Detect State and Data Link Layer Link Active
bits at the USB4 Host Router's Root Port and thus causes hot removal of the
dock.
The crash occurs when pciehp is unbound from one of the dock's Downstream
Ports: pciehp creates a pci_slot on bind and destroys it on unbind. The
pci_slot contains a pointer to the pci_bus below the Downstream Port, but
a reference on that pci_bus is never acquired. The pci_bus is destroyed
before the pci_slot, so a use-after-free ensues when pci_slot_release()
accesses slot->bus.
In principle this should not happen because pci_stop_bus_device() unbinds
pciehp (and therefore destroys the pci_slot) before the pci_bus is
destroyed by pci_remove_bus_device().
However the stacktrace provided by Dennis shows that pciehp is unbound from
pci_remove_bus_device() instead of pci_stop_bus_device(). To understand
the significance of this, one needs to know that the PCI core uses a two
step process to remove a portion of the hierarchy: It first unbinds all
drivers in the sub-hierarchy in pci_stop_bus_device() and then actually
removes the devices in pci_remove_bus_device(). There is no precaution to
prevent driver binding in-between pci_stop_bus_device() and
pci_remove_bus_device().
In Dennis' case, it seems removal of the hierarchy by pciehp races with
driver binding by pci_bus_add_devices(). pciehp is bound to the
Downstream Port after pci_stop_bus_device() has run, so it is unbound by
pci_remove_bus_device() instead of pci_stop_bus_device(). Because the
pci_bus has already been destroyed at that point, accesses to it result in
a use-after-free.
One might conclude that driver binding needs to be prevented after
pci_stop_bus_device() has run. However it seems risky that pci_slot points
to pci_bus without holding a reference. Solely relying on correct ordering
of driver unbind versus pci_bus destruction is certainly not defensive
programming.
If pci_slot has a need to access data in pci_bus, it ought to acquire a
reference. Amend pci_create_slot() accordingly. Dennis reports that the
crash is not reproducible with this change.
Abridged stacktrace:
pcieport 0000:00:07.0: PME: Signaling with IRQ 156
pcieport 0000:00:07.0: pciehp: Slot #12 AttnBtn- PwrCtrl- MRL- AttnInd- PwrInd- HotPlug+ Surprise+ Interlock- NoCompl+ IbPresDis- LLActRep+
pci_bus 0000:20: dev 00, created physical slot 12
pcieport 0000:00:07.0: pciehp: Slot(12): Card not present
...
pcieport 0000:21:02.0: pciehp: pcie_disable_notification: SLOTCTRL d8 write cmd 0
Oops: general protection fault, probably for non-canonical address 0x6b6b6b6b6b6b6b6b: 0000 [#1] PREEMPT SMP NOPTI
CPU: 13 UID: 0 PID: 134 Comm: irq/156-pciehp Not tainted 6.11.0-devel+ #1
RIP: 0010:dev_driver_string+0x12/0x40
pci_destroy_slot
pciehp_remove
pcie_port_remove_service
device_release_driver_internal
bus_remove_device
device_del
device_unregister
remove_iter
device_for_each_child
pcie_portdrv_remove
pci_device_remove
device_release_driver_internal
bus_remove_device
device_del
pci_remove_bus_device (recursive invocation)
pci_remove_bus_device
pciehp_unconfigure_device
pciehp_disable_slot
pciehp_handle_presence_or_link_change
pciehp_ist
In the Linux kernel, the following vulnerability has been resolved:
KVM: arm64: Get rid of userspace_irqchip_in_use
Improper use of userspace_irqchip_in_use led to syzbot hitting the
following WARN_ON() in kvm_timer_update_irq():
WARNING: CPU: 0 PID: 3281 at arch/arm64/kvm/arch_timer.c:459
kvm_timer_update_irq+0x21c/0x394
Call trace:
kvm_timer_update_irq+0x21c/0x394 arch/arm64/kvm/arch_timer.c:459
kvm_timer_vcpu_reset+0x158/0x684 arch/arm64/kvm/arch_timer.c:968
kvm_reset_vcpu+0x3b4/0x560 arch/arm64/kvm/reset.c:264
kvm_vcpu_set_target arch/arm64/kvm/arm.c:1553 [inline]
kvm_arch_vcpu_ioctl_vcpu_init arch/arm64/kvm/arm.c:1573 [inline]
kvm_arch_vcpu_ioctl+0x112c/0x1b3c arch/arm64/kvm/arm.c:1695
kvm_vcpu_ioctl+0x4ec/0xf74 virt/kvm/kvm_main.c:4658
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:907 [inline]
__se_sys_ioctl fs/ioctl.c:893 [inline]
__arm64_sys_ioctl+0x108/0x184 fs/ioctl.c:893
__invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
invoke_syscall+0x78/0x1b8 arch/arm64/kernel/syscall.c:49
el0_svc_common+0xe8/0x1b0 arch/arm64/kernel/syscall.c:132
do_el0_svc+0x40/0x50 arch/arm64/kernel/syscall.c:151
el0_svc+0x54/0x14c arch/arm64/kernel/entry-common.c:712
el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:730
el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:598
The following sequence led to the scenario:
- Userspace creates a VM and a vCPU.
- The vCPU is initialized with KVM_ARM_VCPU_PMU_V3 during
KVM_ARM_VCPU_INIT.
- Without any other setup, such as vGIC or vPMU, userspace issues
KVM_RUN on the vCPU. Since the vPMU is requested, but not setup,
kvm_arm_pmu_v3_enable() fails in kvm_arch_vcpu_run_pid_change().
As a result, KVM_RUN returns after enabling the timer, but before
incrementing 'userspace_irqchip_in_use':
kvm_arch_vcpu_run_pid_change()
ret = kvm_arm_pmu_v3_enable()
if (!vcpu->arch.pmu.created)
return -EINVAL;
if (ret)
return ret;
[...]
if (!irqchip_in_kernel(kvm))
static_branch_inc(&userspace_irqchip_in_use);
- Userspace ignores the error and issues KVM_ARM_VCPU_INIT again.
Since the timer is already enabled, control moves through the
following flow, ultimately hitting the WARN_ON():
kvm_timer_vcpu_reset()
if (timer->enabled)
kvm_timer_update_irq()
if (!userspace_irqchip())
ret = kvm_vgic_inject_irq()
ret = vgic_lazy_init()
if (unlikely(!vgic_initialized(kvm)))
if (kvm->arch.vgic.vgic_model !=
KVM_DEV_TYPE_ARM_VGIC_V2)
return -EBUSY;
WARN_ON(ret);
Theoretically, since userspace_irqchip_in_use's functionality can be
simply replaced by '!irqchip_in_kernel()', get rid of the static key
to avoid the mismanagement, which also helps with the syzbot issue.
In the Linux kernel, the following vulnerability has been resolved:
ALSA: usb-audio: Fix potential out-of-bound accesses for Extigy and Mbox devices
A bogus device can provide a bNumConfigurations value that exceeds the
initial value used in usb_get_configuration for allocating dev->config.
This can lead to out-of-bounds accesses later, e.g. in
usb_destroy_configuration.
In the Linux kernel, the following vulnerability has been resolved:
xen: Fix the issue of resource not being properly released in xenbus_dev_probe()
This patch fixes an issue in the function xenbus_dev_probe(). In the
xenbus_dev_probe() function, within the if (err) branch at line 313, the
program incorrectly returns err directly without releasing the resources
allocated by err = drv->probe(dev, id). As the return value is non-zero,
the upper layers assume the processing logic has failed. However, the probe
operation was performed earlier without a corresponding remove operation.
Since the probe actually allocates resources, failing to perform the remove
operation could lead to problems.
To fix this issue, we followed the resource release logic of the
xenbus_dev_remove() function by adding a new block fail_remove before the
fail_put block. After entering the branch if (err) at line 313, the
function will use a goto statement to jump to the fail_remove block,
ensuring that the previously acquired resources are correctly released,
thus preventing the reference count leak.
This bug was identified by an experimental static analysis tool developed
by our team. The tool specializes in analyzing reference count operations
and detecting potential issues where resources are not properly managed.
In this case, the tool flagged the missing release operation as a
potential problem, which led to the development of this patch.
In the Linux kernel, the following vulnerability has been resolved:
io_uring: check for overflows in io_pin_pages
WARNING: CPU: 0 PID: 5834 at io_uring/memmap.c:144 io_pin_pages+0x149/0x180 io_uring/memmap.c:144
CPU: 0 UID: 0 PID: 5834 Comm: syz-executor825 Not tainted 6.12.0-next-20241118-syzkaller #0
Call Trace:
<TASK>
__io_uaddr_map+0xfb/0x2d0 io_uring/memmap.c:183
io_rings_map io_uring/io_uring.c:2611 [inline]
io_allocate_scq_urings+0x1c0/0x650 io_uring/io_uring.c:3470
io_uring_create+0x5b5/0xc00 io_uring/io_uring.c:3692
io_uring_setup io_uring/io_uring.c:3781 [inline]
...
</TASK>
io_pin_pages()'s uaddr parameter came directly from the user and can be
garbage. Don't just add size to it as it can overflow.
In the Linux kernel, the following vulnerability has been resolved:
wifi: rtlwifi: Drastically reduce the attempts to read efuse in case of failures
Syzkaller reported a hung task with uevent_show() on stack trace. That
specific issue was addressed by another commit [0], but even with that
fix applied (for example, running v6.12-rc5) we face another type of hung
task that comes from the same reproducer [1]. By investigating that, we
could narrow it to the following path:
(a) Syzkaller emulates a Realtek USB WiFi adapter using raw-gadget and
dummy_hcd infrastructure.
(b) During the probe of rtl8192cu, the driver ends-up performing an efuse
read procedure (which is related to EEPROM load IIUC), and here lies the
issue: the function read_efuse() calls read_efuse_byte() many times, as
loop iterations depending on the efuse size (in our example, 512 in total).
This procedure for reading efuse bytes relies in a loop that performs an
I/O read up to *10k* times in case of failures. We measured the time of
the loop inside read_efuse_byte() alone, and in this reproducer (which
involves the dummy_hcd emulation layer), it takes 15 seconds each. As a
consequence, we have the driver stuck in its probe routine for big time,
exposing a stack trace like below if we attempt to reboot the system, for
example:
task:kworker/0:3 state:D stack:0 pid:662 tgid:662 ppid:2 flags:0x00004000
Workqueue: usb_hub_wq hub_event
Call Trace:
__schedule+0xe22/0xeb6
schedule_timeout+0xe7/0x132
__wait_for_common+0xb5/0x12e
usb_start_wait_urb+0xc5/0x1ef
? usb_alloc_urb+0x95/0xa4
usb_control_msg+0xff/0x184
_usbctrl_vendorreq_sync+0xa0/0x161
_usb_read_sync+0xb3/0xc5
read_efuse_byte+0x13c/0x146
read_efuse+0x351/0x5f0
efuse_read_all_map+0x42/0x52
rtl_efuse_shadow_map_update+0x60/0xef
rtl_get_hwinfo+0x5d/0x1c2
rtl92cu_read_eeprom_info+0x10a/0x8d5
? rtl92c_read_chip_version+0x14f/0x17e
rtl_usb_probe+0x323/0x851
usb_probe_interface+0x278/0x34b
really_probe+0x202/0x4a4
__driver_probe_device+0x166/0x1b2
driver_probe_device+0x2f/0xd8
[...]
We propose hereby to drastically reduce the attempts of doing the I/O
reads in case of failures, restricted to USB devices (given that
they're inherently slower than PCIe ones). By retrying up to 10 times
(instead of 10000), we got reponsiveness in the reproducer, while seems
reasonable to believe that there's no sane USB device implementation in
the field requiring this amount of retries at every I/O read in order
to properly work. Based on that assumption, it'd be good to have it
backported to stable but maybe not since driver implementation (the 10k
number comes from day 0), perhaps up to 6.x series makes sense.
[0] Commit 15fffc6a5624 ("driver core: Fix uevent_show() vs driver detach race")
[1] A note about that: this syzkaller report presents multiple reproducers
that differs by the type of emulated USB device. For this specific case,
check the entry from 2024/08/08 06:23 in the list of crashes; the C repro
is available at https://syzkaller.appspot.com/text?tag=ReproC&x=1521fc83980000.
In the Linux kernel, the following vulnerability has been resolved:
smb: prevent use-after-free due to open_cached_dir error paths
If open_cached_dir() encounters an error parsing the lease from the
server, the error handling may race with receiving a lease break,
resulting in open_cached_dir() freeing the cfid while the queued work is
pending.
Update open_cached_dir() to drop refs rather than directly freeing the
cfid.
Have cached_dir_lease_break(), cfids_laundromat_worker(), and
invalidate_all_cached_dirs() clear has_lease immediately while still
holding cfids->cfid_list_lock, and then use this to also simplify the
reference counting in cfids_laundromat_worker() and
invalidate_all_cached_dirs().
Fixes this KASAN splat (which manually injects an error and lease break
in open_cached_dir()):
==================================================================
BUG: KASAN: slab-use-after-free in smb2_cached_lease_break+0x27/0xb0
Read of size 8 at addr ffff88811cc24c10 by task kworker/3:1/65
CPU: 3 UID: 0 PID: 65 Comm: kworker/3:1 Not tainted 6.12.0-rc6-g255cf264e6e5-dirty #87
Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 11/12/2020
Workqueue: cifsiod smb2_cached_lease_break
Call Trace:
<TASK>
dump_stack_lvl+0x77/0xb0
print_report+0xce/0x660
kasan_report+0xd3/0x110
smb2_cached_lease_break+0x27/0xb0
process_one_work+0x50a/0xc50
worker_thread+0x2ba/0x530
kthread+0x17c/0x1c0
ret_from_fork+0x34/0x60
ret_from_fork_asm+0x1a/0x30
</TASK>
Allocated by task 2464:
kasan_save_stack+0x33/0x60
kasan_save_track+0x14/0x30
__kasan_kmalloc+0xaa/0xb0
open_cached_dir+0xa7d/0x1fb0
smb2_query_path_info+0x43c/0x6e0
cifs_get_fattr+0x346/0xf10
cifs_get_inode_info+0x157/0x210
cifs_revalidate_dentry_attr+0x2d1/0x460
cifs_getattr+0x173/0x470
vfs_statx_path+0x10f/0x160
vfs_statx+0xe9/0x150
vfs_fstatat+0x5e/0xc0
__do_sys_newfstatat+0x91/0xf0
do_syscall_64+0x95/0x1a0
entry_SYSCALL_64_after_hwframe+0x76/0x7e
Freed by task 2464:
kasan_save_stack+0x33/0x60
kasan_save_track+0x14/0x30
kasan_save_free_info+0x3b/0x60
__kasan_slab_free+0x51/0x70
kfree+0x174/0x520
open_cached_dir+0x97f/0x1fb0
smb2_query_path_info+0x43c/0x6e0
cifs_get_fattr+0x346/0xf10
cifs_get_inode_info+0x157/0x210
cifs_revalidate_dentry_attr+0x2d1/0x460
cifs_getattr+0x173/0x470
vfs_statx_path+0x10f/0x160
vfs_statx+0xe9/0x150
vfs_fstatat+0x5e/0xc0
__do_sys_newfstatat+0x91/0xf0
do_syscall_64+0x95/0x1a0
entry_SYSCALL_64_after_hwframe+0x76/0x7e
Last potentially related work creation:
kasan_save_stack+0x33/0x60
__kasan_record_aux_stack+0xad/0xc0
insert_work+0x32/0x100
__queue_work+0x5c9/0x870
queue_work_on+0x82/0x90
open_cached_dir+0x1369/0x1fb0
smb2_query_path_info+0x43c/0x6e0
cifs_get_fattr+0x346/0xf10
cifs_get_inode_info+0x157/0x210
cifs_revalidate_dentry_attr+0x2d1/0x460
cifs_getattr+0x173/0x470
vfs_statx_path+0x10f/0x160
vfs_statx+0xe9/0x150
vfs_fstatat+0x5e/0xc0
__do_sys_newfstatat+0x91/0xf0
do_syscall_64+0x95/0x1a0
entry_SYSCALL_64_after_hwframe+0x76/0x7e
The buggy address belongs to the object at ffff88811cc24c00
which belongs to the cache kmalloc-1k of size 1024
The buggy address is located 16 bytes inside of
freed 1024-byte region [ffff88811cc24c00, ffff88811cc25000)
In the Linux kernel, the following vulnerability has been resolved:
smb: client: fix use-after-free of signing key
Customers have reported use-after-free in @ses->auth_key.response with
SMB2.1 + sign mounts which occurs due to following race:
task A task B
cifs_mount()
dfs_mount_share()
get_session()
cifs_mount_get_session() cifs_send_recv()
cifs_get_smb_ses() compound_send_recv()
cifs_setup_session() smb2_setup_request()
kfree_sensitive() smb2_calc_signature()
crypto_shash_setkey() *UAF*
Fix this by ensuring that we have a valid @ses->auth_key.response by
checking whether @ses->ses_status is SES_GOOD or SES_EXITING with
@ses->ses_lock held. After commit 24a9799aa8ef ("smb: client: fix UAF
in smb2_reconnect_server()"), we made sure to call ->logoff() only
when @ses was known to be good (e.g. valid ->auth_key.response), so
it's safe to access signing key when @ses->ses_status == SES_EXITING.