In the Linux kernel, the following vulnerability has been resolved:
KVM: x86: Reject Hyper-V's SEND_IPI hypercalls if local APIC isn't in-kernel
Advertise support for Hyper-V's SEND_IPI and SEND_IPI_EX hypercalls if and
only if the local API is emulated/virtualized by KVM, and explicitly reject
said hypercalls if the local APIC is emulated in userspace, i.e. don't rely
on userspace to opt-in to KVM_CAP_HYPERV_ENFORCE_CPUID.
Rejecting SEND_IPI and SEND_IPI_EX fixes a NULL-pointer dereference if
Hyper-V enlightenments are exposed to the guest without an in-kernel local
APIC:
dump_stack+0xbe/0xfd
__kasan_report.cold+0x34/0x84
kasan_report+0x3a/0x50
__apic_accept_irq+0x3a/0x5c0
kvm_hv_send_ipi.isra.0+0x34e/0x820
kvm_hv_hypercall+0x8d9/0x9d0
kvm_emulate_hypercall+0x506/0x7e0
__vmx_handle_exit+0x283/0xb60
vmx_handle_exit+0x1d/0xd0
vcpu_enter_guest+0x16b0/0x24c0
vcpu_run+0xc0/0x550
kvm_arch_vcpu_ioctl_run+0x170/0x6d0
kvm_vcpu_ioctl+0x413/0xb20
__se_sys_ioctl+0x111/0x160
do_syscal1_64+0x30/0x40
entry_SYSCALL_64_after_hwframe+0x67/0xd1
Note, checking the sending vCPU is sufficient, as the per-VM irqchip_mode
can't be modified after vCPUs are created, i.e. if one vCPU has an
in-kernel local APIC, then all vCPUs have an in-kernel local APIC.
In the Linux kernel, the following vulnerability has been resolved:
drm/amdgpu: avoid buffer overflow attach in smu_sys_set_pp_table()
It malicious user provides a small pptable through sysfs and then
a bigger pptable, it may cause buffer overflow attack in function
smu_sys_set_pp_table().
In the Linux kernel, the following vulnerability has been resolved:
batman-adv: fix panic during interface removal
Reference counting is used to ensure that
batadv_hardif_neigh_node and batadv_hard_iface
are not freed before/during
batadv_v_elp_throughput_metric_update work is
finished.
But there isn't a guarantee that the hard if will
remain associated with a soft interface up until
the work is finished.
This fixes a crash triggered by reboot that looks
like this:
Call trace:
batadv_v_mesh_free+0xd0/0x4dc [batman_adv]
batadv_v_elp_throughput_metric_update+0x1c/0xa4
process_one_work+0x178/0x398
worker_thread+0x2e8/0x4d0
kthread+0xd8/0xdc
ret_from_fork+0x10/0x20
(the batadv_v_mesh_free call is misleading,
and does not actually happen)
I was able to make the issue happen more reliably
by changing hardif_neigh->bat_v.metric_work work
to be delayed work. This allowed me to track down
and confirm the fix.
[sven@narfation.org: prevent entering batadv_v_elp_get_throughput without
soft_iface]
In the Linux kernel, the following vulnerability has been resolved:
ndisc: use RCU protection in ndisc_alloc_skb()
ndisc_alloc_skb() can be called without RTNL or RCU being held.
Add RCU protection to avoid possible UAF.
In the Linux kernel, the following vulnerability has been resolved:
ipv6: use RCU protection in ip6_default_advmss()
ip6_default_advmss() needs rcu protection to make
sure the net structure it reads does not disappear.
In the Linux kernel, the following vulnerability has been resolved:
ipv4: use RCU protection in __ip_rt_update_pmtu()
__ip_rt_update_pmtu() must use RCU protection to make
sure the net structure it reads does not disappear.
In the Linux kernel, the following vulnerability has been resolved:
clocksource: Use migrate_disable() to avoid calling get_random_u32() in atomic context
The following bug report happened with a PREEMPT_RT kernel:
BUG: sleeping function called from invalid context at kernel/locking/spinlock_rt.c:48
in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 2012, name: kwatchdog
preempt_count: 1, expected: 0
RCU nest depth: 0, expected: 0
get_random_u32+0x4f/0x110
clocksource_verify_choose_cpus+0xab/0x1a0
clocksource_verify_percpu.part.0+0x6b/0x330
clocksource_watchdog_kthread+0x193/0x1a0
It is due to the fact that clocksource_verify_choose_cpus() is invoked with
preemption disabled. This function invokes get_random_u32() to obtain
random numbers for choosing CPUs. The batched_entropy_32 local lock and/or
the base_crng.lock spinlock in driver/char/random.c will be acquired during
the call. In PREEMPT_RT kernel, they are both sleeping locks and so cannot
be acquired in atomic context.
Fix this problem by using migrate_disable() to allow smp_processor_id() to
be reliably used without introducing atomic context. preempt_disable() is
then called after clocksource_verify_choose_cpus() but before the
clocksource measurement is being run to avoid introducing unexpected
latency.
In the Linux kernel, the following vulnerability has been resolved:
net: ipv6: fix dst ref loops in rpl, seg6 and ioam6 lwtunnels
Some lwtunnels have a dst cache for post-transformation dst.
If the packet destination did not change we may end up recording
a reference to the lwtunnel in its own cache, and the lwtunnel
state will never be freed.
Discovered by the ioam6.sh test, kmemleak was recently fixed
to catch per-cpu memory leaks. I'm not sure if rpl and seg6
can actually hit this, but in principle I don't see why not.
In the Linux kernel, the following vulnerability has been resolved:
partitions: mac: fix handling of bogus partition table
Fix several issues in partition probing:
- The bailout for a bad partoffset must use put_dev_sector(), since the
preceding read_part_sector() succeeded.
- If the partition table claims a silly sector size like 0xfff bytes
(which results in partition table entries straddling sector boundaries),
bail out instead of accessing out-of-bounds memory.
- We must not assume that the partition table contains proper NUL
termination - use strnlen() and strncmp() instead of strlen() and
strcmp().
In the Linux kernel, the following vulnerability has been resolved:
vsock: Keep the binding until socket destruction
Preserve sockets bindings; this includes both resulting from an explicit
bind() and those implicitly bound through autobind during connect().
Prevents socket unbinding during a transport reassignment, which fixes a
use-after-free:
1. vsock_create() (refcnt=1) calls vsock_insert_unbound() (refcnt=2)
2. transport->release() calls vsock_remove_bound() without checking if
sk was bound and moved to bound list (refcnt=1)
3. vsock_bind() assumes sk is in unbound list and before
__vsock_insert_bound(vsock_bound_sockets()) calls
__vsock_remove_bound() which does:
list_del_init(&vsk->bound_table); // nop
sock_put(&vsk->sk); // refcnt=0
BUG: KASAN: slab-use-after-free in __vsock_bind+0x62e/0x730
Read of size 4 at addr ffff88816b46a74c by task a.out/2057
dump_stack_lvl+0x68/0x90
print_report+0x174/0x4f6
kasan_report+0xb9/0x190
__vsock_bind+0x62e/0x730
vsock_bind+0x97/0xe0
__sys_bind+0x154/0x1f0
__x64_sys_bind+0x6e/0xb0
do_syscall_64+0x93/0x1b0
entry_SYSCALL_64_after_hwframe+0x76/0x7e
Allocated by task 2057:
kasan_save_stack+0x1e/0x40
kasan_save_track+0x10/0x30
__kasan_slab_alloc+0x85/0x90
kmem_cache_alloc_noprof+0x131/0x450
sk_prot_alloc+0x5b/0x220
sk_alloc+0x2c/0x870
__vsock_create.constprop.0+0x2e/0xb60
vsock_create+0xe4/0x420
__sock_create+0x241/0x650
__sys_socket+0xf2/0x1a0
__x64_sys_socket+0x6e/0xb0
do_syscall_64+0x93/0x1b0
entry_SYSCALL_64_after_hwframe+0x76/0x7e
Freed by task 2057:
kasan_save_stack+0x1e/0x40
kasan_save_track+0x10/0x30
kasan_save_free_info+0x37/0x60
__kasan_slab_free+0x4b/0x70
kmem_cache_free+0x1a1/0x590
__sk_destruct+0x388/0x5a0
__vsock_bind+0x5e1/0x730
vsock_bind+0x97/0xe0
__sys_bind+0x154/0x1f0
__x64_sys_bind+0x6e/0xb0
do_syscall_64+0x93/0x1b0
entry_SYSCALL_64_after_hwframe+0x76/0x7e
refcount_t: addition on 0; use-after-free.
WARNING: CPU: 7 PID: 2057 at lib/refcount.c:25 refcount_warn_saturate+0xce/0x150
RIP: 0010:refcount_warn_saturate+0xce/0x150
__vsock_bind+0x66d/0x730
vsock_bind+0x97/0xe0
__sys_bind+0x154/0x1f0
__x64_sys_bind+0x6e/0xb0
do_syscall_64+0x93/0x1b0
entry_SYSCALL_64_after_hwframe+0x76/0x7e
refcount_t: underflow; use-after-free.
WARNING: CPU: 7 PID: 2057 at lib/refcount.c:28 refcount_warn_saturate+0xee/0x150
RIP: 0010:refcount_warn_saturate+0xee/0x150
vsock_remove_bound+0x187/0x1e0
__vsock_release+0x383/0x4a0
vsock_release+0x90/0x120
__sock_release+0xa3/0x250
sock_close+0x14/0x20
__fput+0x359/0xa80
task_work_run+0x107/0x1d0
do_exit+0x847/0x2560
do_group_exit+0xb8/0x250
__x64_sys_exit_group+0x3a/0x50
x64_sys_call+0xfec/0x14f0
do_syscall_64+0x93/0x1b0
entry_SYSCALL_64_after_hwframe+0x76/0x7e