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:
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:
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.
In the Linux kernel, the following vulnerability has been resolved:
ALSA: pcm: Add sanity NULL check for the default mmap fault handler
A driver might allow the mmap access before initializing its
runtime->dma_area properly. Add a proper NULL check before passing to
virt_to_page() for avoiding a panic.
In the Linux kernel, the following vulnerability has been resolved:
SUNRPC: make sure cache entry active before cache_show
The function `c_show` was called with protection from RCU. This only
ensures that `cp` will not be freed. Therefore, the reference count for
`cp` can drop to zero, which will trigger a refcount use-after-free
warning when `cache_get` is called. To resolve this issue, use
`cache_get_rcu` to ensure that `cp` remains active.
------------[ cut here ]------------
refcount_t: addition on 0; use-after-free.
WARNING: CPU: 7 PID: 822 at lib/refcount.c:25
refcount_warn_saturate+0xb1/0x120
CPU: 7 UID: 0 PID: 822 Comm: cat Not tainted 6.12.0-rc3+ #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
1.16.1-2.fc37 04/01/2014
RIP: 0010:refcount_warn_saturate+0xb1/0x120
Call Trace:
<TASK>
c_show+0x2fc/0x380 [sunrpc]
seq_read_iter+0x589/0x770
seq_read+0x1e5/0x270
proc_reg_read+0xe1/0x140
vfs_read+0x125/0x530
ksys_read+0xc1/0x160
do_syscall_64+0x5f/0x170
entry_SYSCALL_64_after_hwframe+0x76/0x7e
In the Linux kernel, the following vulnerability has been resolved:
ALSA: usb-audio: Fix out of bounds reads when finding clock sources
The current USB-audio driver code doesn't check bLength of each
descriptor at traversing for clock descriptors. That is, when a
device provides a bogus descriptor with a shorter bLength, the driver
might hit out-of-bounds reads.
For addressing it, this patch adds sanity checks to the validator
functions for the clock descriptor traversal. When the descriptor
length is shorter than expected, it's skipped in the loop.
For the clock source and clock multiplier descriptors, we can just
check bLength against the sizeof() of each descriptor type.
OTOH, the clock selector descriptor of UAC2 and UAC3 has an array
of bNrInPins elements and two more fields at its tail, hence those
have to be checked in addition to the sizeof() check.
In the Linux kernel, the following vulnerability has been resolved:
NFSD: Prevent a potential integer overflow
If the tag length is >= U32_MAX - 3 then the "length + 4" addition
can result in an integer overflow. Address this by splitting the
decoding into several steps so that decode_cb_compound4res() does
not have to perform arithmetic on the unsafe length value.