In the Linux kernel, the following vulnerability has been resolved:
locking/ww_mutex/test: Fix potential workqueue corruption
In some cases running with the test-ww_mutex code, I was seeing
odd behavior where sometimes it seemed flush_workqueue was
returning before all the work threads were finished.
Often this would cause strange crashes as the mutexes would be
freed while they were being used.
Looking at the code, there is a lifetime problem as the
controlling thread that spawns the work allocates the
"struct stress" structures that are passed to the workqueue
threads. Then when the workqueue threads are finished,
they free the stress struct that was passed to them.
Unfortunately the workqueue work_struct node is in the stress
struct. Which means the work_struct is freed before the work
thread returns and while flush_workqueue is waiting.
It seems like a better idea to have the controlling thread
both allocate and free the stress structures, so that we can
be sure we don't corrupt the workqueue by freeing the structure
prematurely.
So this patch reworks the test to do so, and with this change
I no longer see the early flush_workqueue returns.
In the Linux kernel, the following vulnerability has been resolved:
llc: verify mac len before reading mac header
LLC reads the mac header with eth_hdr without verifying that the skb
has an Ethernet header.
Syzbot was able to enter llc_rcv on a tun device. Tun can insert
packets without mac len and with user configurable skb->protocol
(passing a tun_pi header when not configuring IFF_NO_PI).
BUG: KMSAN: uninit-value in llc_station_ac_send_test_r net/llc/llc_station.c:81 [inline]
BUG: KMSAN: uninit-value in llc_station_rcv+0x6fb/0x1290 net/llc/llc_station.c:111
llc_station_ac_send_test_r net/llc/llc_station.c:81 [inline]
llc_station_rcv+0x6fb/0x1290 net/llc/llc_station.c:111
llc_rcv+0xc5d/0x14a0 net/llc/llc_input.c:218
__netif_receive_skb_one_core net/core/dev.c:5523 [inline]
__netif_receive_skb+0x1a6/0x5a0 net/core/dev.c:5637
netif_receive_skb_internal net/core/dev.c:5723 [inline]
netif_receive_skb+0x58/0x660 net/core/dev.c:5782
tun_rx_batched+0x3ee/0x980 drivers/net/tun.c:1555
tun_get_user+0x54c5/0x69c0 drivers/net/tun.c:2002
Add a mac_len test before all three eth_hdr(skb) calls under net/llc.
There are further uses in include/net/llc_pdu.h. All these are
protected by a test skb->protocol == ETH_P_802_2. Which does not
protect against this tun scenario.
But the mac_len test added in this patch in llc_fixup_skb will
indirectly protect those too. That is called from llc_rcv before any
other LLC code.
It is tempting to just add a blanket mac_len check in llc_rcv, but
not sure whether that could break valid LLC paths that do not assume
an Ethernet header. 802.2 LLC may be used on top of non-802.3
protocols in principle. The below referenced commit shows that used
to, on top of Token Ring.
At least one of the three eth_hdr uses goes back to before the start
of git history. But the one that syzbot exercises is introduced in
this commit. That commit is old enough (2008), that effectively all
stable kernels should receive this.
In the Linux kernel, the following vulnerability has been resolved:
drm/panel: fix a possible null pointer dereference
In versatile_panel_get_modes(), the return value of drm_mode_duplicate()
is assigned to mode, which will lead to a NULL pointer dereference
on failure of drm_mode_duplicate(). Add a check to avoid npd.
In the Linux kernel, the following vulnerability has been resolved:
drm/amdkfd: Fix a race condition of vram buffer unref in svm code
prange->svm_bo unref can happen in both mmu callback and a callback after
migrate to system ram. Both are async call in different tasks. Sync svm_bo
unref operation to avoid random "use-after-free".
In the Linux kernel, the following vulnerability has been resolved:
drm/panel/panel-tpo-tpg110: fix a possible null pointer dereference
In tpg110_get_modes(), the return value of drm_mode_duplicate() is
assigned to mode, which will lead to a NULL pointer dereference on
failure of drm_mode_duplicate(). Add a check to avoid npd.
In the Linux kernel, the following vulnerability has been resolved:
wifi: ath12k: fix possible out-of-bound read in ath12k_htt_pull_ppdu_stats()
len is extracted from HTT message and could be an unexpected value in
case errors happen, so add validation before using to avoid possible
out-of-bound read in the following message iteration and parsing.
The same issue also applies to ppdu_info->ppdu_stats.common.num_users,
so validate it before using too.
These are found during code review.
Compile test only.
In the Linux kernel, the following vulnerability has been resolved:
cpu/hotplug: Don't offline the last non-isolated CPU
If a system has isolated CPUs via the "isolcpus=" command line parameter,
then an attempt to offline the last housekeeping CPU will result in a
WARN_ON() when rebuilding the scheduler domains and a subsequent panic due
to and unhandled empty CPU mas in partition_sched_domains_locked().
cpuset_hotplug_workfn()
rebuild_sched_domains_locked()
ndoms = generate_sched_domains(&doms, &attr);
cpumask_and(doms[0], top_cpuset.effective_cpus, housekeeping_cpumask(HK_FLAG_DOMAIN));
Thus results in an empty CPU mask which triggers the warning and then the
subsequent crash:
WARNING: CPU: 4 PID: 80 at kernel/sched/topology.c:2366 build_sched_domains+0x120c/0x1408
Call trace:
build_sched_domains+0x120c/0x1408
partition_sched_domains_locked+0x234/0x880
rebuild_sched_domains_locked+0x37c/0x798
rebuild_sched_domains+0x30/0x58
cpuset_hotplug_workfn+0x2a8/0x930
Unable to handle kernel paging request at virtual address fffe80027ab37080
partition_sched_domains_locked+0x318/0x880
rebuild_sched_domains_locked+0x37c/0x798
Aside of the resulting crash, it does not make any sense to offline the last
last housekeeping CPU.
Prevent this by masking out the non-housekeeping CPUs when selecting a
target CPU for initiating the CPU unplug operation via the work queue.
In the Linux kernel, the following vulnerability has been resolved:
wifi: mac80211: don't return unset power in ieee80211_get_tx_power()
We can get a UBSAN warning if ieee80211_get_tx_power() returns the
INT_MIN value mac80211 internally uses for "unset power level".
UBSAN: signed-integer-overflow in net/wireless/nl80211.c:3816:5
-2147483648 * 100 cannot be represented in type 'int'
CPU: 0 PID: 20433 Comm: insmod Tainted: G WC OE
Call Trace:
dump_stack+0x74/0x92
ubsan_epilogue+0x9/0x50
handle_overflow+0x8d/0xd0
__ubsan_handle_mul_overflow+0xe/0x10
nl80211_send_iface+0x688/0x6b0 [cfg80211]
[...]
cfg80211_register_wdev+0x78/0xb0 [cfg80211]
cfg80211_netdev_notifier_call+0x200/0x620 [cfg80211]
[...]
ieee80211_if_add+0x60e/0x8f0 [mac80211]
ieee80211_register_hw+0xda5/0x1170 [mac80211]
In this case, simply return an error instead, to indicate
that no data is available.
In the Linux kernel, the following vulnerability has been resolved:
scsi: libfc: Fix potential NULL pointer dereference in fc_lport_ptp_setup()
fc_lport_ptp_setup() did not check the return value of fc_rport_create()
which can return NULL and would cause a NULL pointer dereference. Address
this issue by checking return value of fc_rport_create() and log error
message on fc_rport_create() failed.