In the Linux kernel, the following vulnerability has been resolved:
net/9p: use a dedicated spinlock for trans_fd
Shamelessly copying the explanation from Tetsuo Handa's suggested
patch[1] (slightly reworded):
syzbot is reporting inconsistent lock state in p9_req_put()[2],
for p9_tag_remove() from p9_req_put() from IRQ context is using
spin_lock_irqsave() on "struct p9_client"->lock but trans_fd
(not from IRQ context) is using spin_lock().
Since the locks actually protect different things in client.c and in
trans_fd.c, just replace trans_fd.c's lock by a new one specific to the
transport (client.c's protect the idr for fid/tag allocations,
while trans_fd.c's protects its own req list and request status field
that acts as the transport's state machine)
In the Linux kernel, the following vulnerability has been resolved:
netlink: Bounds-check struct nlmsgerr creation
In preparation for FORTIFY_SOURCE doing bounds-check on memcpy(),
switch from __nlmsg_put to nlmsg_put(), and explain the bounds check
for dealing with the memcpy() across a composite flexible array struct.
Avoids this future run-time warning:
memcpy: detected field-spanning write (size 32) of single field "&errmsg->msg" at net/netlink/af_netlink.c:2447 (size 16)
In the Linux kernel, the following vulnerability has been resolved:
9p/trans_fd: always use O_NONBLOCK read/write
syzbot is reporting hung task at p9_fd_close() [1], for p9_mux_poll_stop()
from p9_conn_destroy() from p9_fd_close() is failing to interrupt already
started kernel_read() from p9_fd_read() from p9_read_work() and/or
kernel_write() from p9_fd_write() from p9_write_work() requests.
Since p9_socket_open() sets O_NONBLOCK flag, p9_mux_poll_stop() does not
need to interrupt kernel_read()/kernel_write(). However, since p9_fd_open()
does not set O_NONBLOCK flag, but pipe blocks unless signal is pending,
p9_mux_poll_stop() needs to interrupt kernel_read()/kernel_write() when
the file descriptor refers to a pipe. In other words, pipe file descriptor
needs to be handled as if socket file descriptor.
We somehow need to interrupt kernel_read()/kernel_write() on pipes.
A minimal change, which this patch is doing, is to set O_NONBLOCK flag
from p9_fd_open(), for O_NONBLOCK flag does not affect reading/writing
of regular files. But this approach changes O_NONBLOCK flag on userspace-
supplied file descriptors (which might break userspace programs), and
O_NONBLOCK flag could be changed by userspace. It would be possible to set
O_NONBLOCK flag every time p9_fd_read()/p9_fd_write() is invoked, but still
remains small race window for clearing O_NONBLOCK flag.
If we don't want to manipulate O_NONBLOCK flag, we might be able to
surround kernel_read()/kernel_write() with set_thread_flag(TIF_SIGPENDING)
and recalc_sigpending(). Since p9_read_work()/p9_write_work() works are
processed by kernel threads which process global system_wq workqueue,
signals could not be delivered from remote threads when p9_mux_poll_stop()
from p9_conn_destroy() from p9_fd_close() is called. Therefore, calling
set_thread_flag(TIF_SIGPENDING)/recalc_sigpending() every time would be
needed if we count on signals for making kernel_read()/kernel_write()
non-blocking.
[Dominique: add comment at Christian's suggestion]
In the Linux kernel, the following vulnerability has been resolved:
gfs2: Check sb_bsize_shift after reading superblock
Fuzzers like to scribble over sb_bsize_shift but in reality it's very
unlikely that this field would be corrupted on its own. Nevertheless it
should be checked to avoid the possibility of messy mount errors due to
bad calculations. It's always a fixed value based on the block size so
we can just check that it's the expected value.
Tested with:
mkfs.gfs2 -O -p lock_nolock /dev/vdb
for i in 0 -1 64 65 32 33; do
gfs2_edit -p sb field sb_bsize_shift $i /dev/vdb
mount /dev/vdb /mnt/test && umount /mnt/test
done
Before this patch we get a withdraw after
[ 76.413681] gfs2: fsid=loop0.0: fatal: invalid metadata block
[ 76.413681] bh = 19 (type: exp=5, found=4)
[ 76.413681] function = gfs2_meta_buffer, file = fs/gfs2/meta_io.c, line = 492
and with UBSAN configured we also get complaints like
[ 76.373395] UBSAN: shift-out-of-bounds in fs/gfs2/ops_fstype.c:295:19
[ 76.373815] shift exponent 4294967287 is too large for 64-bit type 'long unsigned int'
After the patch, these complaints don't appear, mount fails immediately
and we get an explanation in dmesg.
In the Linux kernel, the following vulnerability has been resolved:
ntfs: check overflow when iterating ATTR_RECORDs
Kernel iterates over ATTR_RECORDs in mft record in ntfs_attr_find().
Because the ATTR_RECORDs are next to each other, kernel can get the next
ATTR_RECORD from end address of current ATTR_RECORD, through current
ATTR_RECORD length field.
The problem is that during iteration, when kernel calculates the end
address of current ATTR_RECORD, kernel may trigger an integer overflow bug
in executing `a = (ATTR_RECORD*)((u8*)a + le32_to_cpu(a->length))`. This
may wrap, leading to a forever iteration on 32bit systems.
This patch solves it by adding some checks on calculating end address
of current ATTR_RECORD during iteration.
In the Linux kernel, the following vulnerability has been resolved:
PM: hibernate: Avoid deadlock in hibernate_compressor_param_set()
syzbot reported a deadlock in lock_system_sleep() (see below).
The write operation to "/sys/module/hibernate/parameters/compressor"
conflicts with the registration of ieee80211 device, resulting in a deadlock
when attempting to acquire system_transition_mutex under param_lock.
To avoid this deadlock, change hibernate_compressor_param_set() to use
mutex_trylock() for attempting to acquire system_transition_mutex and
return -EBUSY when it fails.
Task flags need not be saved or adjusted before calling
mutex_trylock(&system_transition_mutex) because the caller is not going
to end up waiting for this mutex and if it runs concurrently with system
suspend in progress, it will be frozen properly when it returns to user
space.
syzbot report:
syz-executor895/5833 is trying to acquire lock:
ffffffff8e0828c8 (system_transition_mutex){+.+.}-{4:4}, at: lock_system_sleep+0x87/0xa0 kernel/power/main.c:56
but task is already holding lock:
ffffffff8e07dc68 (param_lock){+.+.}-{4:4}, at: kernel_param_lock kernel/params.c:607 [inline]
ffffffff8e07dc68 (param_lock){+.+.}-{4:4}, at: param_attr_store+0xe6/0x300 kernel/params.c:586
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #3 (param_lock){+.+.}-{4:4}:
__mutex_lock_common kernel/locking/mutex.c:585 [inline]
__mutex_lock+0x19b/0xb10 kernel/locking/mutex.c:730
ieee80211_rate_control_ops_get net/mac80211/rate.c:220 [inline]
rate_control_alloc net/mac80211/rate.c:266 [inline]
ieee80211_init_rate_ctrl_alg+0x18d/0x6b0 net/mac80211/rate.c:1015
ieee80211_register_hw+0x20cd/0x4060 net/mac80211/main.c:1531
mac80211_hwsim_new_radio+0x304e/0x54e0 drivers/net/wireless/virtual/mac80211_hwsim.c:5558
init_mac80211_hwsim+0x432/0x8c0 drivers/net/wireless/virtual/mac80211_hwsim.c:6910
do_one_initcall+0x128/0x700 init/main.c:1257
do_initcall_level init/main.c:1319 [inline]
do_initcalls init/main.c:1335 [inline]
do_basic_setup init/main.c:1354 [inline]
kernel_init_freeable+0x5c7/0x900 init/main.c:1568
kernel_init+0x1c/0x2b0 init/main.c:1457
ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
-> #2 (rtnl_mutex){+.+.}-{4:4}:
__mutex_lock_common kernel/locking/mutex.c:585 [inline]
__mutex_lock+0x19b/0xb10 kernel/locking/mutex.c:730
wg_pm_notification drivers/net/wireguard/device.c:80 [inline]
wg_pm_notification+0x49/0x180 drivers/net/wireguard/device.c:64
notifier_call_chain+0xb7/0x410 kernel/notifier.c:85
notifier_call_chain_robust kernel/notifier.c:120 [inline]
blocking_notifier_call_chain_robust kernel/notifier.c:345 [inline]
blocking_notifier_call_chain_robust+0xc9/0x170 kernel/notifier.c:333
pm_notifier_call_chain_robust+0x27/0x60 kernel/power/main.c:102
snapshot_open+0x189/0x2b0 kernel/power/user.c:77
misc_open+0x35a/0x420 drivers/char/misc.c:179
chrdev_open+0x237/0x6a0 fs/char_dev.c:414
do_dentry_open+0x735/0x1c40 fs/open.c:956
vfs_open+0x82/0x3f0 fs/open.c:1086
do_open fs/namei.c:3830 [inline]
path_openat+0x1e88/0x2d80 fs/namei.c:3989
do_filp_open+0x20c/0x470 fs/namei.c:4016
do_sys_openat2+0x17a/0x1e0 fs/open.c:1428
do_sys_open fs/open.c:1443 [inline]
__do_sys_openat fs/open.c:1459 [inline]
__se_sys_openat fs/open.c:1454 [inline]
__x64_sys_openat+0x175/0x210 fs/open.c:1454
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #1 ((pm_chain_head).rwsem){++++}-{4:4}:
down_read+0x9a/0x330 kernel/locking/rwsem.c:1524
blocking_notifier_call_chain_robust kerne
---truncated---
In the Linux kernel, the following vulnerability has been resolved:
PCI: vmd: Make vmd_dev::cfg_lock a raw_spinlock_t type
The access to the PCI config space via pci_ops::read and pci_ops::write is
a low-level hardware access. The functions can be accessed with disabled
interrupts even on PREEMPT_RT. The pci_lock is a raw_spinlock_t for this
purpose.
A spinlock_t becomes a sleeping lock on PREEMPT_RT, so it cannot be
acquired with disabled interrupts. The vmd_dev::cfg_lock is accessed in
the same context as the pci_lock.
Make vmd_dev::cfg_lock a raw_spinlock_t type so it can be used with
interrupts disabled.
This was reported as:
BUG: sleeping function called from invalid context at kernel/locking/spinlock_rt.c:48
Call Trace:
rt_spin_lock+0x4e/0x130
vmd_pci_read+0x8d/0x100 [vmd]
pci_user_read_config_byte+0x6f/0xe0
pci_read_config+0xfe/0x290
sysfs_kf_bin_read+0x68/0x90
[bigeasy: reword commit message]
Tested-off-by: Luis Claudio R. Goncalves <lgoncalv@redhat.com>
[kwilczynski: commit log]
[bhelgaas: add back report info from
https://lore.kernel.org/lkml/20241218115951.83062-1-ryotkkr98@gmail.com/]
In the Linux kernel, the following vulnerability has been resolved:
net: vlan: don't propagate flags on open
With the device instance lock, there is now a possibility of a deadlock:
[ 1.211455] ============================================
[ 1.211571] WARNING: possible recursive locking detected
[ 1.211687] 6.14.0-rc5-01215-g032756b4ca7a-dirty #5 Not tainted
[ 1.211823] --------------------------------------------
[ 1.211936] ip/184 is trying to acquire lock:
[ 1.212032] ffff8881024a4c30 (&dev->lock){+.+.}-{4:4}, at: dev_set_allmulti+0x4e/0xb0
[ 1.212207]
[ 1.212207] but task is already holding lock:
[ 1.212332] ffff8881024a4c30 (&dev->lock){+.+.}-{4:4}, at: dev_open+0x50/0xb0
[ 1.212487]
[ 1.212487] other info that might help us debug this:
[ 1.212626] Possible unsafe locking scenario:
[ 1.212626]
[ 1.212751] CPU0
[ 1.212815] ----
[ 1.212871] lock(&dev->lock);
[ 1.212944] lock(&dev->lock);
[ 1.213016]
[ 1.213016] *** DEADLOCK ***
[ 1.213016]
[ 1.213143] May be due to missing lock nesting notation
[ 1.213143]
[ 1.213294] 3 locks held by ip/184:
[ 1.213371] #0: ffffffff838b53e0 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock+0x1b/0xa0
[ 1.213543] #1: ffffffff84e5fc70 (&net->rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock+0x37/0xa0
[ 1.213727] #2: ffff8881024a4c30 (&dev->lock){+.+.}-{4:4}, at: dev_open+0x50/0xb0
[ 1.213895]
[ 1.213895] stack backtrace:
[ 1.213991] CPU: 0 UID: 0 PID: 184 Comm: ip Not tainted 6.14.0-rc5-01215-g032756b4ca7a-dirty #5
[ 1.213993] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014
[ 1.213994] Call Trace:
[ 1.213995] <TASK>
[ 1.213996] dump_stack_lvl+0x8e/0xd0
[ 1.214000] print_deadlock_bug+0x28b/0x2a0
[ 1.214020] lock_acquire+0xea/0x2a0
[ 1.214027] __mutex_lock+0xbf/0xd40
[ 1.214038] dev_set_allmulti+0x4e/0xb0 # real_dev->flags & IFF_ALLMULTI
[ 1.214040] vlan_dev_open+0xa5/0x170 # ndo_open on vlandev
[ 1.214042] __dev_open+0x145/0x270
[ 1.214046] __dev_change_flags+0xb0/0x1e0
[ 1.214051] netif_change_flags+0x22/0x60 # IFF_UP vlandev
[ 1.214053] dev_change_flags+0x61/0xb0 # for each device in group from dev->vlan_info
[ 1.214055] vlan_device_event+0x766/0x7c0 # on netdevsim0
[ 1.214058] notifier_call_chain+0x78/0x120
[ 1.214062] netif_open+0x6d/0x90
[ 1.214064] dev_open+0x5b/0xb0 # locks netdevsim0
[ 1.214066] bond_enslave+0x64c/0x1230
[ 1.214075] do_set_master+0x175/0x1e0 # on netdevsim0
[ 1.214077] do_setlink+0x516/0x13b0
[ 1.214094] rtnl_newlink+0xaba/0xb80
[ 1.214132] rtnetlink_rcv_msg+0x440/0x490
[ 1.214144] netlink_rcv_skb+0xeb/0x120
[ 1.214150] netlink_unicast+0x1f9/0x320
[ 1.214153] netlink_sendmsg+0x346/0x3f0
[ 1.214157] __sock_sendmsg+0x86/0xb0
[ 1.214160] ____sys_sendmsg+0x1c8/0x220
[ 1.214164] ___sys_sendmsg+0x28f/0x2d0
[ 1.214179] __x64_sys_sendmsg+0xef/0x140
[ 1.214184] do_syscall_64+0xec/0x1d0
[ 1.214190] entry_SYSCALL_64_after_hwframe+0x77/0x7f
[ 1.214191] RIP: 0033:0x7f2d1b4a7e56
Device setup:
netdevsim0 (down)
^ ^
bond netdevsim1.100@netdevsim1 allmulticast=on (down)
When we enslave the lower device (netdevsim0) which has a vlan, we
propagate vlan's allmuti/promisc flags during ndo_open. This causes
(re)locking on of the real_dev.
Propagate allmulti/promisc on flags change, not on the open. There
is a slight semantics change that vlans that are down now propagate
the flags, but this seems unlikely to result in the real issues.
Reproducer:
echo 0 1 > /sys/bus/netdevsim/new_device
dev_path=$(ls -d /sys/bus/netdevsim/devices/netdevsim0/net/*)
dev=$(echo $dev_path | rev | cut -d/ -f1 | rev)
ip link set dev $dev name netdevsim0
ip link set dev netdevsim0 up
ip link add link netdevsim0 name netdevsim0.100 type vlan id 100
ip link set dev netdevsim0.100 allm
---truncated---
In the Linux kernel, the following vulnerability has been resolved:
jfs: add sanity check for agwidth in dbMount
The width in dmapctl of the AG is zero, it trigger a divide error when
calculating the control page level in dbAllocAG.
To avoid this issue, add a check for agwidth in dbAllocAG.