In the Linux kernel, the following vulnerability has been resolved:
dpaa2-switch: prevent ZERO_SIZE_PTR dereference when num_ifs is zero
The driver allocates arrays for ports, FDBs, and filter blocks using
kcalloc() with ethsw->sw_attr.num_ifs as the element count. When the
device reports zero interfaces (either due to hardware configuration
or firmware issues), kcalloc(0, ...) returns ZERO_SIZE_PTR (0x10)
instead of NULL.
Later in dpaa2_switch_probe(), the NAPI initialization unconditionally
accesses ethsw->ports[0]->netdev, which attempts to dereference
ZERO_SIZE_PTR (address 0x10), resulting in a kernel panic.
Add a check to ensure num_ifs is greater than zero after retrieving
device attributes. This prevents the zero-sized allocations and
subsequent invalid pointer dereference.
In the Linux kernel, the following vulnerability has been resolved:
spi: tegra210-quad: Protect curr_xfer check in IRQ handler
Now that all other accesses to curr_xfer are done under the lock,
protect the curr_xfer NULL check in tegra_qspi_isr_thread() with the
spinlock. Without this protection, the following race can occur:
CPU0 (ISR thread) CPU1 (timeout path)
---------------- -------------------
if (!tqspi->curr_xfer)
// sees non-NULL
spin_lock()
tqspi->curr_xfer = NULL
spin_unlock()
handle_*_xfer()
spin_lock()
t = tqspi->curr_xfer // NULL!
... t->len ... // NULL dereference!
With this patch, all curr_xfer accesses are now properly synchronized.
Although all accesses to curr_xfer are done under the lock, in
tegra_qspi_isr_thread() it checks for NULL, releases the lock and
reacquires it later in handle_cpu_based_xfer()/handle_dma_based_xfer().
There is a potential for an update in between, which could cause a NULL
pointer dereference.
To handle this, add a NULL check inside the handlers after acquiring
the lock. This ensures that if the timeout path has already cleared
curr_xfer, the handler will safely return without dereferencing the
NULL pointer.
In the Linux kernel, the following vulnerability has been resolved:
ALSA: usb-audio: Prevent excessive number of frames
In this case, the user constructed the parameters with maxpacksize 40
for rate 22050 / pps 1000, and packsize[0] 22 packsize[1] 23. The buffer
size for each data URB is maxpacksize * packets, which in this example
is 40 * 6 = 240; When the user performs a write operation to send audio
data into the ALSA PCM playback stream, the calculated number of frames
is packsize[0] * packets = 264, which exceeds the allocated URB buffer
size, triggering the out-of-bounds (OOB) issue reported by syzbot [1].
Added a check for the number of single data URB frames when calculating
the number of frames to prevent [1].
[1]
BUG: KASAN: slab-out-of-bounds in copy_to_urb+0x261/0x460 sound/usb/pcm.c:1487
Write of size 264 at addr ffff88804337e800 by task syz.0.17/5506
Call Trace:
copy_to_urb+0x261/0x460 sound/usb/pcm.c:1487
prepare_playback_urb+0x953/0x13d0 sound/usb/pcm.c:1611
prepare_outbound_urb+0x377/0xc50 sound/usb/endpoint.c:333
In the Linux kernel, the following vulnerability has been resolved:
macvlan: fix error recovery in macvlan_common_newlink()
valis provided a nice repro to crash the kernel:
ip link add p1 type veth peer p2
ip link set address 00:00:00:00:00:20 dev p1
ip link set up dev p1
ip link set up dev p2
ip link add mv0 link p2 type macvlan mode source
ip link add invalid% link p2 type macvlan mode source macaddr add 00:00:00:00:00:20
ping -c1 -I p1 1.2.3.4
He also gave a very detailed analysis:
<quote valis>
The issue is triggered when a new macvlan link is created with
MACVLAN_MODE_SOURCE mode and MACVLAN_MACADDR_ADD (or
MACVLAN_MACADDR_SET) parameter, lower device already has a macvlan
port and register_netdevice() called from macvlan_common_newlink()
fails (e.g. because of the invalid link name).
In this case macvlan_hash_add_source is called from
macvlan_change_sources() / macvlan_common_newlink():
This adds a reference to vlan to the port's vlan_source_hash using
macvlan_source_entry.
vlan is a pointer to the priv data of the link that is being created.
When register_netdevice() fails, the error is returned from
macvlan_newlink() to rtnl_newlink_create():
if (ops->newlink)
err = ops->newlink(dev, ¶ms, extack);
else
err = register_netdevice(dev);
if (err < 0) {
free_netdev(dev);
goto out;
}
and free_netdev() is called, causing a kvfree() on the struct
net_device that is still referenced in the source entry attached to
the lower device's macvlan port.
Now all packets sent on the macvlan port with a matching source mac
address will trigger a use-after-free in macvlan_forward_source().
</quote valis>
With all that, my fix is to make sure we call macvlan_flush_sources()
regardless of @create value whenever "goto destroy_macvlan_port;"
path is taken.
Many thanks to valis for following up on this issue.
In the Linux kernel, the following vulnerability has been resolved:
linkwatch: use __dev_put() in callers to prevent UAF
After linkwatch_do_dev() calls __dev_put() to release the linkwatch
reference, the device refcount may drop to 1. At this point,
netdev_run_todo() can proceed (since linkwatch_sync_dev() sees an
empty list and returns without blocking), wait for the refcount to
become 1 via netdev_wait_allrefs_any(), and then free the device
via kobject_put().
This creates a use-after-free when __linkwatch_run_queue() tries to
call netdev_unlock_ops() on the already-freed device.
Note that adding netdev_lock_ops()/netdev_unlock_ops() pair in
netdev_run_todo() before kobject_put() would not work, because
netdev_lock_ops() is conditional - it only locks when
netdev_need_ops_lock() returns true. If the device doesn't require
ops_lock, linkwatch won't hold any lock, and netdev_run_todo()
acquiring the lock won't provide synchronization.
Fix this by moving __dev_put() from linkwatch_do_dev() to its
callers. The device reference logically pairs with de-listing the
device, so it's reasonable for the caller that did the de-listing
to release it. This allows placing __dev_put() after all device
accesses are complete, preventing UAF.
The bug can be reproduced by adding mdelay(2000) after
linkwatch_do_dev() in __linkwatch_run_queue(), then running:
ip tuntap add mode tun name tun_test
ip link set tun_test up
ip link set tun_test carrier off
ip link set tun_test carrier on
sleep 0.5
ip tuntap del mode tun name tun_test
KASAN report:
==================================================================
BUG: KASAN: use-after-free in netdev_need_ops_lock include/net/netdev_lock.h:33 [inline]
BUG: KASAN: use-after-free in netdev_unlock_ops include/net/netdev_lock.h:47 [inline]
BUG: KASAN: use-after-free in __linkwatch_run_queue+0x865/0x8a0 net/core/link_watch.c:245
Read of size 8 at addr ffff88804de5c008 by task kworker/u32:10/8123
CPU: 0 UID: 0 PID: 8123 Comm: kworker/u32:10 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Workqueue: events_unbound linkwatch_event
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:378 [inline]
print_report+0x156/0x4c9 mm/kasan/report.c:482
kasan_report+0xdf/0x1a0 mm/kasan/report.c:595
netdev_need_ops_lock include/net/netdev_lock.h:33 [inline]
netdev_unlock_ops include/net/netdev_lock.h:47 [inline]
__linkwatch_run_queue+0x865/0x8a0 net/core/link_watch.c:245
linkwatch_event+0x8f/0xc0 net/core/link_watch.c:304
process_one_work+0x9c2/0x1840 kernel/workqueue.c:3257
process_scheduled_works kernel/workqueue.c:3340 [inline]
worker_thread+0x5da/0xe40 kernel/workqueue.c:3421
kthread+0x3b3/0x730 kernel/kthread.c:463
ret_from_fork+0x754/0xaf0 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
</TASK>
==================================================================
In the Linux kernel, the following vulnerability has been resolved:
scsi: target: iscsi: Fix use-after-free in iscsit_dec_session_usage_count()
In iscsit_dec_session_usage_count(), the function calls complete() while
holding the sess->session_usage_lock. Similar to the connection usage count
logic, the waiter signaled by complete() (e.g., in the session release
path) may wake up and free the iscsit_session structure immediately.
This creates a race condition where the current thread may attempt to
execute spin_unlock_bh() on a session structure that has already been
deallocated, resulting in a KASAN slab-use-after-free.
To resolve this, release the session_usage_lock before calling complete()
to ensure all dereferences of the sess pointer are finished before the
waiter is allowed to proceed with deallocation.
In the Linux kernel, the following vulnerability has been resolved:
rust_binder: correctly handle FDA objects of length zero
Fix a bug where an empty FDA (fd array) object with 0 fds would cause an
out-of-bounds error. The previous implementation used `skip == 0` to
mean "this is a pointer fixup", but 0 is also the correct skip length
for an empty FDA. If the FDA is at the end of the buffer, then this
results in an attempt to write 8-bytes out of bounds. This is caught and
results in an EINVAL error being returned to userspace.
The pattern of using `skip == 0` as a special value originates from the
C-implementation of Binder. As part of fixing this bug, this pattern is
replaced with a Rust enum.
I considered the alternate option of not pushing a fixup when the length
is zero, but I think it's cleaner to just get rid of the zero-is-special
stuff.
The root cause of this bug was diagnosed by Gemini CLI on first try. I
used the following prompt:
> There appears to be a bug in @drivers/android/binder/thread.rs where
> the Fixups oob bug is triggered with 316 304 316 324. This implies
> that we somehow ended up with a fixup where buffer A has a pointer to
> buffer B, but the pointer is located at an index in buffer A that is
> out of bounds. Please investigate the code to find the bug. You may
> compare with @drivers/android/binder.c that implements this correctly.
In the Linux kernel, the following vulnerability has been resolved:
cgroup/dmem: avoid pool UAF
An UAF issue was observed:
BUG: KASAN: slab-use-after-free in page_counter_uncharge+0x65/0x150
Write of size 8 at addr ffff888106715440 by task insmod/527
CPU: 4 UID: 0 PID: 527 Comm: insmod 6.19.0-rc7-next-20260129+ #11
Tainted: [O]=OOT_MODULE
Call Trace:
<TASK>
dump_stack_lvl+0x82/0xd0
kasan_report+0xca/0x100
kasan_check_range+0x39/0x1c0
page_counter_uncharge+0x65/0x150
dmem_cgroup_uncharge+0x1f/0x260
Allocated by task 527:
Freed by task 0:
The buggy address belongs to the object at ffff888106715400
which belongs to the cache kmalloc-512 of size 512
The buggy address is located 64 bytes inside of
freed 512-byte region [ffff888106715400, ffff888106715600)
The buggy address belongs to the physical page:
Memory state around the buggy address:
ffff888106715300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff888106715380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888106715400: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff888106715480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888106715500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
The issue occurs because a pool can still be held by a caller after its
associated memory region is unregistered. The current implementation frees
the pool even if users still hold references to it (e.g., before uncharge
operations complete).
This patch adds a reference counter to each pool, ensuring that a pool is
only freed when its reference count drops to zero.
In the Linux kernel, the following vulnerability has been resolved:
HID: Intel-thc-hid: Intel-thc: Add safety check for reading DMA buffer
Add DMA buffer readiness check before reading DMA buffer to avoid
unexpected NULL pointer accessing.