In the Linux kernel, the following vulnerability has been resolved:
serial: protect uart_port_dtr_rts() in uart_shutdown() too
Commit af224ca2df29 (serial: core: Prevent unsafe uart port access, part
3) added few uport == NULL checks. It added one to uart_shutdown(), so
the commit assumes, uport can be NULL in there. But right after that
protection, there is an unprotected "uart_port_dtr_rts(uport, false);"
call. That is invoked only if HUPCL is set, so I assume that is the
reason why we do not see lots of these reports.
Or it cannot be NULL at this point at all for some reason :P.
Until the above is investigated, stay on the safe side and move this
dereference to the if too.
I got this inconsistency from Coverity under CID 1585130. Thanks.
In the Linux kernel, the following vulnerability has been resolved:
netfilter: xtables: avoid NFPROTO_UNSPEC where needed
syzbot managed to call xt_cluster match via ebtables:
WARNING: CPU: 0 PID: 11 at net/netfilter/xt_cluster.c:72 xt_cluster_mt+0x196/0x780
[..]
ebt_do_table+0x174b/0x2a40
Module registers to NFPROTO_UNSPEC, but it assumes ipv4/ipv6 packet
processing. As this is only useful to restrict locally terminating
TCP/UDP traffic, register this for ipv4 and ipv6 family only.
Pablo points out that this is a general issue, direct users of the
set/getsockopt interface can call into targets/matches that were only
intended for use with ip(6)tables.
Check all UNSPEC matches and targets for similar issues:
- matches and targets are fine except if they assume skb_network_header()
is valid -- this is only true when called from inet layer: ip(6) stack
pulls the ip/ipv6 header into linear data area.
- targets that return XT_CONTINUE or other xtables verdicts must be
restricted too, they are incompatbile with the ebtables traverser, e.g.
EBT_CONTINUE is a completely different value than XT_CONTINUE.
Most matches/targets are changed to register for NFPROTO_IPV4/IPV6, as
they are provided for use by ip(6)tables.
The MARK target is also used by arptables, so register for NFPROTO_ARP too.
While at it, bail out if connbytes fails to enable the corresponding
conntrack family.
This change passes the selftests in iptables.git.
In the Linux kernel, the following vulnerability has been resolved:
net: Fix an unsafe loop on the list
The kernel may crash when deleting a genetlink family if there are still
listeners for that family:
Oops: Kernel access of bad area, sig: 11 [#1]
...
NIP [c000000000c080bc] netlink_update_socket_mc+0x3c/0xc0
LR [c000000000c0f764] __netlink_clear_multicast_users+0x74/0xc0
Call Trace:
__netlink_clear_multicast_users+0x74/0xc0
genl_unregister_family+0xd4/0x2d0
Change the unsafe loop on the list to a safe one, because inside the
loop there is an element removal from this list.
In the Linux kernel, the following vulnerability has been resolved:
net/9p: Fix a potential socket leak in p9_socket_open
Both p9_fd_create_tcp() and p9_fd_create_unix() will call
p9_socket_open(). If the creation of p9_trans_fd fails,
p9_fd_create_tcp() and p9_fd_create_unix() will return an
error directly instead of releasing the cscoket, which will
result in a socket leak.
This patch adds sock_release() to fix the leak issue.
In the Linux kernel, the following vulnerability has been resolved:
net: phy: fix null-ptr-deref while probe() failed
I got a null-ptr-deref report as following when doing fault injection test:
BUG: kernel NULL pointer dereference, address: 0000000000000058
Oops: 0000 [#1] PREEMPT SMP KASAN PTI
CPU: 1 PID: 253 Comm: 507-spi-dm9051 Tainted: G B N 6.1.0-rc3+
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014
RIP: 0010:klist_put+0x2d/0xd0
Call Trace:
<TASK>
klist_remove+0xf1/0x1c0
device_release_driver_internal+0x23e/0x2d0
bus_remove_device+0x1bd/0x240
device_del+0x357/0x770
phy_device_remove+0x11/0x30
mdiobus_unregister+0xa5/0x140
release_nodes+0x6a/0xa0
devres_release_all+0xf8/0x150
device_unbind_cleanup+0x19/0xd0
//probe path:
phy_device_register()
device_add()
phy_connect
phy_attach_direct() //set device driver
probe() //it's failed, driver is not bound
device_bind_driver() // probe failed, it's not called
//remove path:
phy_device_remove()
device_del()
device_release_driver_internal()
__device_release_driver() //dev->drv is not NULL
klist_remove() <- knode_driver is not added yet, cause null-ptr-deref
In phy_attach_direct(), after setting the 'dev->driver', probe() fails,
device_bind_driver() is not called, so the knode_driver->n_klist is not
set, then it causes null-ptr-deref in __device_release_driver() while
deleting device. Fix this by setting dev->driver to NULL in the error
path in phy_attach_direct().
In the Linux kernel, the following vulnerability has been resolved:
hwmon: (ibmpex) Fix possible UAF when ibmpex_register_bmc() fails
Smatch report warning as follows:
drivers/hwmon/ibmpex.c:509 ibmpex_register_bmc() warn:
'&data->list' not removed from list
If ibmpex_find_sensors() fails in ibmpex_register_bmc(), data will
be freed, but data->list will not be removed from driver_data.bmc_data,
then list traversal may cause UAF.
Fix by removeing it from driver_data.bmc_data before free().
In the Linux kernel, the following vulnerability has been resolved:
btrfs: qgroup: fix sleep from invalid context bug in btrfs_qgroup_inherit()
Syzkaller reported BUG as follows:
BUG: sleeping function called from invalid context at
include/linux/sched/mm.h:274
Call Trace:
<TASK>
dump_stack_lvl+0xcd/0x134
__might_resched.cold+0x222/0x26b
kmem_cache_alloc+0x2e7/0x3c0
update_qgroup_limit_item+0xe1/0x390
btrfs_qgroup_inherit+0x147b/0x1ee0
create_subvol+0x4eb/0x1710
btrfs_mksubvol+0xfe5/0x13f0
__btrfs_ioctl_snap_create+0x2b0/0x430
btrfs_ioctl_snap_create_v2+0x25a/0x520
btrfs_ioctl+0x2a1c/0x5ce0
__x64_sys_ioctl+0x193/0x200
do_syscall_64+0x35/0x80
Fix this by calling qgroup_dirty() on @dstqgroup, and update limit item in
btrfs_run_qgroups() later outside of the spinlock context.
In the Linux kernel, the following vulnerability has been resolved:
tracing: Free buffers when a used dynamic event is removed
After 65536 dynamic events have been added and removed, the "type" field
of the event then uses the first type number that is available (not
currently used by other events). A type number is the identifier of the
binary blobs in the tracing ring buffer (known as events) to map them to
logic that can parse the binary blob.
The issue is that if a dynamic event (like a kprobe event) is traced and
is in the ring buffer, and then that event is removed (because it is
dynamic, which means it can be created and destroyed), if another dynamic
event is created that has the same number that new event's logic on
parsing the binary blob will be used.
To show how this can be an issue, the following can crash the kernel:
# cd /sys/kernel/tracing
# for i in `seq 65536`; do
echo 'p:kprobes/foo do_sys_openat2 $arg1:u32' > kprobe_events
# done
For every iteration of the above, the writing to the kprobe_events will
remove the old event and create a new one (with the same format) and
increase the type number to the next available on until the type number
reaches over 65535 which is the max number for the 16 bit type. After it
reaches that number, the logic to allocate a new number simply looks for
the next available number. When an dynamic event is removed, that number
is then available to be reused by the next dynamic event created. That is,
once the above reaches the max number, the number assigned to the event in
that loop will remain the same.
Now that means deleting one dynamic event and created another will reuse
the previous events type number. This is where bad things can happen.
After the above loop finishes, the kprobes/foo event which reads the
do_sys_openat2 function call's first parameter as an integer.
# echo 1 > kprobes/foo/enable
# cat /etc/passwd > /dev/null
# cat trace
cat-2211 [005] .... 2007.849603: foo: (do_sys_openat2+0x0/0x130) arg1=4294967196
cat-2211 [005] .... 2007.849620: foo: (do_sys_openat2+0x0/0x130) arg1=4294967196
cat-2211 [005] .... 2007.849838: foo: (do_sys_openat2+0x0/0x130) arg1=4294967196
cat-2211 [005] .... 2007.849880: foo: (do_sys_openat2+0x0/0x130) arg1=4294967196
# echo 0 > kprobes/foo/enable
Now if we delete the kprobe and create a new one that reads a string:
# echo 'p:kprobes/foo do_sys_openat2 +0($arg2):string' > kprobe_events
And now we can the trace:
# cat trace
sendmail-1942 [002] ..... 530.136320: foo: (do_sys_openat2+0x0/0x240) arg1= cat-2046 [004] ..... 530.930817: foo: (do_sys_openat2+0x0/0x240) arg1="������������������������������������������������������������������������������������������������"
cat-2046 [004] ..... 530.930961: foo: (do_sys_openat2+0x0/0x240) arg1="������������������������������������������������������������������������������������������������"
cat-2046 [004] ..... 530.934278: foo: (do_sys_openat2+0x0/0x240) arg1="������������������������������������������������������������������������������������������������"
cat-2046 [004] ..... 530.934563: foo: (do_sys_openat2+0x0/0x240) arg1="���������������������������������������
---truncated---