In the Linux kernel, the following vulnerability has been resolved:
llc: do not use skb_get() before dev_queue_xmit()
syzbot is able to crash hosts [1], using llc and devices
not supporting IFF_TX_SKB_SHARING.
In this case, e1000 driver calls eth_skb_pad(), while
the skb is shared.
Simply replace skb_get() by skb_clone() in net/llc/llc_s_ac.c
Note that e1000 driver might have an issue with pktgen,
because it does not clear IFF_TX_SKB_SHARING, this is an
orthogonal change.
We need to audit other skb_get() uses in net/llc.
[1]
kernel BUG at net/core/skbuff.c:2178 !
Oops: invalid opcode: 0000 [#1] PREEMPT SMP KASAN NOPTI
CPU: 0 UID: 0 PID: 16371 Comm: syz.2.2764 Not tainted 6.14.0-rc4-syzkaller-00052-gac9c34d1e45a #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
RIP: 0010:pskb_expand_head+0x6ce/0x1240 net/core/skbuff.c:2178
Call Trace:
<TASK>
__skb_pad+0x18a/0x610 net/core/skbuff.c:2466
__skb_put_padto include/linux/skbuff.h:3843 [inline]
skb_put_padto include/linux/skbuff.h:3862 [inline]
eth_skb_pad include/linux/etherdevice.h:656 [inline]
e1000_xmit_frame+0x2d99/0x5800 drivers/net/ethernet/intel/e1000/e1000_main.c:3128
__netdev_start_xmit include/linux/netdevice.h:5151 [inline]
netdev_start_xmit include/linux/netdevice.h:5160 [inline]
xmit_one net/core/dev.c:3806 [inline]
dev_hard_start_xmit+0x9a/0x7b0 net/core/dev.c:3822
sch_direct_xmit+0x1ae/0xc30 net/sched/sch_generic.c:343
__dev_xmit_skb net/core/dev.c:4045 [inline]
__dev_queue_xmit+0x13d4/0x43e0 net/core/dev.c:4621
dev_queue_xmit include/linux/netdevice.h:3313 [inline]
llc_sap_action_send_test_c+0x268/0x320 net/llc/llc_s_ac.c:144
llc_exec_sap_trans_actions net/llc/llc_sap.c:153 [inline]
llc_sap_next_state net/llc/llc_sap.c:182 [inline]
llc_sap_state_process+0x239/0x510 net/llc/llc_sap.c:209
llc_ui_sendmsg+0xd0d/0x14e0 net/llc/af_llc.c:993
sock_sendmsg_nosec net/socket.c:718 [inline]
In the Linux kernel, the following vulnerability has been resolved:
usb: renesas_usbhs: Flush the notify_hotplug_work
When performing continuous unbind/bind operations on the USB drivers
available on the Renesas RZ/G2L SoC, a kernel crash with the message
"Unable to handle kernel NULL pointer dereference at virtual address"
may occur. This issue points to the usbhsc_notify_hotplug() function.
Flush the delayed work to avoid its execution when driver resources are
unavailable.
In the Linux kernel, the following vulnerability has been resolved:
vlan: enforce underlying device type
Currently, VLAN devices can be created on top of non-ethernet devices.
Besides the fact that it doesn't make much sense, this also causes a
bug which leaks the address of a kernel function to usermode.
When creating a VLAN device, we initialize GARP (garp_init_applicant)
and MRP (mrp_init_applicant) for the underlying device.
As part of the initialization process, we add the multicast address of
each applicant to the underlying device, by calling dev_mc_add.
__dev_mc_add uses dev->addr_len to determine the length of the new
multicast address.
This causes an out-of-bounds read if dev->addr_len is greater than 6,
since the multicast addresses provided by GARP and MRP are only 6
bytes long.
This behaviour can be reproduced using the following commands:
ip tunnel add gretest mode ip6gre local ::1 remote ::2 dev lo
ip l set up dev gretest
ip link add link gretest name vlantest type vlan id 100
Then, the following command will display the address of garp_pdu_rcv:
ip maddr show | grep 01:80:c2:00:00:21
Fix the bug by enforcing the type of the underlying device during VLAN
device initialization.
In the Linux kernel, the following vulnerability has been resolved:
ppp: Fix KMSAN uninit-value warning with bpf
Syzbot caught an "KMSAN: uninit-value" warning [1], which is caused by the
ppp driver not initializing a 2-byte header when using socket filter.
The following code can generate a PPP filter BPF program:
'''
struct bpf_program fp;
pcap_t *handle;
handle = pcap_open_dead(DLT_PPP_PPPD, 65535);
pcap_compile(handle, &fp, "ip and outbound", 0, 0);
bpf_dump(&fp, 1);
'''
Its output is:
'''
(000) ldh [2]
(001) jeq #0x21 jt 2 jf 5
(002) ldb [0]
(003) jeq #0x1 jt 4 jf 5
(004) ret #65535
(005) ret #0
'''
Wen can find similar code at the following link:
https://github.com/ppp-project/ppp/blob/master/pppd/options.c#L1680
The maintainer of this code repository is also the original maintainer
of the ppp driver.
As you can see the BPF program skips 2 bytes of data and then reads the
'Protocol' field to determine if it's an IP packet. Then it read the first
byte of the first 2 bytes to determine the direction.
The issue is that only the first byte indicating direction is initialized
in current ppp driver code while the second byte is not initialized.
For normal BPF programs generated by libpcap, uninitialized data won't be
used, so it's not a problem. However, for carefully crafted BPF programs,
such as those generated by syzkaller [2], which start reading from offset
0, the uninitialized data will be used and caught by KMSAN.
[1] https://syzkaller.appspot.com/bug?extid=853242d9c9917165d791
[2] https://syzkaller.appspot.com/text?tag=ReproC&x=11994913980000
In the Linux kernel, the following vulnerability has been resolved:
wifi: nl80211: reject cooked mode if it is set along with other flags
It is possible to set both MONITOR_FLAG_COOK_FRAMES and MONITOR_FLAG_ACTIVE
flags simultaneously on the same monitor interface from the userspace. This
causes a sub-interface to be created with no IEEE80211_SDATA_IN_DRIVER bit
set because the monitor interface is in the cooked state and it takes
precedence over all other states. When the interface is then being deleted
the kernel calls WARN_ONCE() from check_sdata_in_driver() because of missing
that bit.
Fix this by rejecting MONITOR_FLAG_COOK_FRAMES if it is set along with
other flags.
Found by Linux Verification Center (linuxtesting.org) with Syzkaller.
In the Linux kernel, the following vulnerability has been resolved:
wifi: cfg80211: regulatory: improve invalid hints checking
Syzbot keeps reporting an issue [1] that occurs when erroneous symbols
sent from userspace get through into user_alpha2[] via
regulatory_hint_user() call. Such invalid regulatory hints should be
rejected.
While a sanity check from commit 47caf685a685 ("cfg80211: regulatory:
reject invalid hints") looks to be enough to deter these very cases,
there is a way to get around it due to 2 reasons.
1) The way isalpha() works, symbols other than latin lower and
upper letters may be used to determine a country/domain.
For instance, greek letters will also be considered upper/lower
letters and for such characters isalpha() will return true as well.
However, ISO-3166-1 alpha2 codes should only hold latin
characters.
2) While processing a user regulatory request, between
reg_process_hint_user() and regulatory_hint_user() there happens to
be a call to queue_regulatory_request() which modifies letters in
request->alpha2[] with toupper(). This works fine for latin symbols,
less so for weird letter characters from the second part of _ctype[].
Syzbot triggers a warning in is_user_regdom_saved() by first sending
over an unexpected non-latin letter that gets malformed by toupper()
into a character that ends up failing isalpha() check.
Prevent this by enhancing is_an_alpha2() to ensure that incoming
symbols are latin letters and nothing else.
[1] Syzbot report:
------------[ cut here ]------------
Unexpected user alpha2: A�
WARNING: CPU: 1 PID: 964 at net/wireless/reg.c:442 is_user_regdom_saved net/wireless/reg.c:440 [inline]
WARNING: CPU: 1 PID: 964 at net/wireless/reg.c:442 restore_alpha2 net/wireless/reg.c:3424 [inline]
WARNING: CPU: 1 PID: 964 at net/wireless/reg.c:442 restore_regulatory_settings+0x3c0/0x1e50 net/wireless/reg.c:3516
Modules linked in:
CPU: 1 UID: 0 PID: 964 Comm: kworker/1:2 Not tainted 6.12.0-rc5-syzkaller-00044-gc1e939a21eb1 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Workqueue: events_power_efficient crda_timeout_work
RIP: 0010:is_user_regdom_saved net/wireless/reg.c:440 [inline]
RIP: 0010:restore_alpha2 net/wireless/reg.c:3424 [inline]
RIP: 0010:restore_regulatory_settings+0x3c0/0x1e50 net/wireless/reg.c:3516
...
Call Trace:
<TASK>
crda_timeout_work+0x27/0x50 net/wireless/reg.c:542
process_one_work kernel/workqueue.c:3229 [inline]
process_scheduled_works+0xa65/0x1850 kernel/workqueue.c:3310
worker_thread+0x870/0xd30 kernel/workqueue.c:3391
kthread+0x2f2/0x390 kernel/kthread.c:389
ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
</TASK>
In the Linux kernel, the following vulnerability has been resolved:
cifs: fix potential memory leaks in session setup
Make sure to free cifs_ses::auth_key.response before allocating it as
we might end up leaking memory in reconnect or mounting.
In the Linux kernel, the following vulnerability has been resolved:
netlink: prevent potential spectre v1 gadgets
Most netlink attributes are parsed and validated from
__nla_validate_parse() or validate_nla()
u16 type = nla_type(nla);
if (type == 0 || type > maxtype) {
/* error or continue */
}
@type is then used as an array index and can be used
as a Spectre v1 gadget.
array_index_nospec() can be used to prevent leaking
content of kernel memory to malicious users.
This should take care of vast majority of netlink uses,
but an audit is needed to take care of others where
validation is not yet centralized in core netlink functions.
In the Linux kernel, the following vulnerability has been resolved:
ALSA: hda/via: Avoid potential array out-of-bound in add_secret_dac_path()
snd_hda_get_connections() can return a negative error code.
It may lead to accessing 'conn' array at a negative index.
Found by Linux Verification Center (linuxtesting.org) with SVACE.