| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| In the Linux kernel, the following vulnerability has been resolved:
dcache: don't put a mountpoint on a dentry that's being removed
rmdir(), unlink() and rename() call dont_mount() on the victim and then
detach_mounts() with the victim's inode locked. do_lock_mount() takes
the inode lock of the mountpoint and checks cant_mount() so a mount
can't show up after detach_mounts().
But attach_recursive_mnt() makes a second mountpoint for the root of the
source mount so that the mounts already located at the destination can
be put on top of it. No inode is locked for that one and d_set_mounted()
only refuses a dentry that is unlinked. Between detach_mounts() and
d_delete() the victim is still hashed:
rmrace: b passed dont_mount() and detach_mounts(), sleeping
T2: move_mount(S, /tmp/plcant/x, BENEATH) = 0 errno 0 ()
T1: rmdir(/tmp/plcant/d/b) = 0 errno 0
109 107 0:61 /d/b//deleted /tmp/plcant/x rw,relatime - tmpfs tmpfs rw
108 109 0:63 / /tmp/plcant/x rw,relatime - tmpfs T rw
A bind mount of the directory that's being removed is moved beneath an
existing mount while the rmdir() is located between the two calls. The
mount ends up on the removed directory and nothing will ever detach it.
Check cant_mount() in d_set_mounted() as well. dont_mount() raises the
flag under d_lock before detach_mounts() runs so either the mountpoint
is set first and detach_mounts() finds the mount or the flag is seen and
the mount is refused. |
| In the Linux kernel, the following vulnerability has been resolved:
namespace: unhash a dentry before detaching the mounts on it
unlink(), rmdir() and rename() remove the entry from the filesystem,
call detach_mounts() on the entry with the inode locked and then call
d_delete() once the inode is unlocked.
The thing is that between detach_mounts() and d_delete() the dentry is
still hashed and positive. But after detach_mounts() nothing covers the
dentry anymore. A lookup that finds this dentry in the dcache can
uncover what the mounts hid.
That's a problem when unlinking files or directories that are
mountpoints in other mount namespaces. Everybody who had the underlying
entry covered can race the detach_mount() call until d_delete() has run.
The race window isn't all that small. It encompasses namespace_unlock()
with a full synchronize_rcu_expedited() grace period and the
inode_unlock() of the entry.
In my experiments three walkers that kept trying read an overmounted
file in 11938 of the 16140 unlinks that removed its mountpoint from a
bind mount of the filesystem within a minute.
Fun fact, d_invalidate() has the same ordering problem but gets it
right. It unhashes the dentry first and detaches the mounts afterwards.
Let's do the same in __detach_mounts():
- A lookup that hasn't found the dentry yet misses it in the dcache and
waits for the directory lock that the caller holds until the name is
gone for good.
- A lockless lookup that found it already fails the mount_lock check
while the dentry still counts as a mountpoint and the d_seq check once
it doesn't, and retries.
This fixes the lockless path. We still need to fix the reference count
lookup in a follow-up patch.
So d_drop() the dentry. The dentry stays positive and held but can't be
found anymore. Then proceed with the detach and unlink.
Reproducer:
The reads were counted with the program below, three walkers for 60 s
in a VM with 4 CPUs. The race window is stretched with the debug patch
pasted here. fs.detach_race_walk_us sleeps in lookup_fast() once it
found a mountpoint dentry and before its mounts are crossed.
fs.detach_race_unlink_us sleeps in vfs_unlink() between detach_mounts()
and d_delete().
// SPDX-License-Identifier: GPL-2.0
/*
* unlink_covered: unlink a file that is a mountpoint in a detached copy of
* its mount, against lookups that open it through that copy.
*
* A is a tmpfs with the file f1 (content SECRET_F) and the plain file
* MARK_A. A' is an open_tree(OPEN_TREE_CLONE) copy of A with MARK_A bound
* on A'/f1, held through an O_PATH fd on its root once the tree fd is
* closed. Walkers open f1 through that fd while the driver unlinks A/f1,
* where nothing is mounted on it. A walker may read MARK_A or get ENOENT.
* A read of SECRET_F is a hit: the name was found after its mount was
* gone. The lockless walks use openat2(RESOLVE_CACHED).
*
* usage: unlink_covered [-t seconds] [-w walkers]
*/
#ifndef _GNU_SOURCE
#define _GNU_SOURCE
#endif
#include <errno.h>
#include <fcntl.h>
#include <pthread.h>
#include <stdatomic.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/mount.h>
#include <sys/stat.h>
#include <sys/syscall.h>
#include <linux/openat2.h>
#ifndef __NR_open_tree
#define __NR_open_tree 428
#endif
#ifndef __NR_move_mount
#define __NR_move_mount 429
#endif
#ifndef __NR_openat2
#define __NR_openat2 437
#endif
#ifndef OPEN_TREE_CLONE
#define OPEN_TREE_CLONE 1
#endif
#ifndef OPEN_TREE_CLOEXEC
#define OPEN_TREE_CLOEXEC O_CLOEXEC
#endif
#ifndef MOVE_MOUNT_F_EMPTY_PATH
#define MOVE_MOUNT_F_EMPTY_PATH 0x00000004
#endif
#define WORK "/tmp/uc"
#define ADIR WORK "/A"
static int duration = 60, nwalkers = 3;
static atomic_int stop, writer_waiting;
static pthread_rwlock_t cur_lock = PTHREAD_RWLOCK_INITIALIZER;
static int cur_fd = -1; /* the root of A', -1 wh
---truncated--- |
| In the Linux kernel, the following vulnerability has been resolved:
namespace: refuse an automount below a mount that is in no namespace
It's possible to add autmounts even when the parent mount isn't in the
mount namespace of the caller. The only requirement we have is that the
parent mount namespace must not be NULL, i.e., unmounted.
Problem is that clone_private_mount() has MNT_NS_INTERNAL which makes
that trivially true. So that passes the test and attach_recursive_mnt()
accepts that as a mount point and funny enough, count_mounts()
dereferences MNT_NS_INTERNAL. The problem is it is an error pointer...
So we can reach this in userspace via fanotify. A filesystem mark on the
lower filesystem of an overlay reports paths on the layer clone and
reading the event hands out a descriptor on it. For example with debugfs
as the lower layer it goes kaboom:
openat(evfd, "tracing", O_DIRECTORY)
Oops: general protection fault
KASAN: null-ptr-deref in range [0x1d0-0x1d7]
RIP: 0010:count_mounts+0x35/0x200
attach_recursive_mnt
finish_automount
And since that sleeping beauty happens under namespace_sem held for
writing every mount operation on the system blocks from then on.
Congrats.
Use is_mounted() instead which rejects unmounted and internal mounts
alike. The open fails with EINVAL just as it did before
clone_private_mount() used MNT_NS_INTERNAL. |
| In the Linux kernel, the following vulnerability has been resolved:
namespace: handle mount locking for automounts correctly
If mounts are propagated across user namespaces, attach_recursive_mnt()
locks every copy of the source mount to protect overmounts from
vanishing and revealing the underlying files or directories.
The user namespace is taken from the caller's mount namespaces since
this is where the mounts end up. Except, that's not always true.
Automounts may legitimately get popped in by tasks located in a
different mount and user namespace during path lookup.
Then check doesn't make sense at that point. The copy in the namespace
of the parent - which may be the host's - is now locked and the host
cannot change the flags of its own mounts anymore.
Here's the reproducer:
- host has debugfs mounted nosuid,nodev,noexec and shared
- tracefs automount below it is not yet active
- hand a child process a directory descriptor on that mount
- child process enters auser and mount namespace
- child process' namespace now holds a locked copy of the host's debugfs
mount that receives propagation from it
- child process stats "tracing/." through the descriptor
- lookup runs on the host's mount so the automount lands below the host's mount
- propagation puts a copy below the child's copy
- both try to clear the flags on the mount they got, with a bind remount:
host, on its own automount: MS_REMOUNT|MS_BIND = EPERM
child, on the copy in its namespace: MS_REMOUNT|MS_BIND = 0
So the lock landed on the host's mount instead of the child's copy.
Congrats. So we need to compare with the owner of the namespace the
mount actually gets mounted on. For all regular cases that is the
caller's mount namespace and so nothing changes.
Detached trees in anonymous mount namespaces by be handed over via
SCM_RIGHTS or inherited in other ways on purpose so the attaching task's
mount namespace is authoritative, not the creator of the detached tree. |
| In the Linux kernel, the following vulnerability has been resolved:
gpio: exar: initialize the ID before registering its cleanup
devm_add_action_or_reset() invokes the cleanup action immediately when
registering the action fails. gpio_exar_probe() currently stores the
allocated ID in exar_gpio only after registering the action, so that
failure makes exar_devm_ida_free() release ID 0. If the allocated ID is
nonzero, this leaks that ID and can free ID 0 belonging to another device.
Store the ID before registering the cleanup action so both the immediate
failure path and normal device teardown release the correct allocation. |
| In the Linux kernel, the following vulnerability has been resolved:
drm/vc4: Free the BO cache size list on teardown
vc4_bo_cache_destroy() purges the cached BOs but never frees the size
list, leaking it on every unbind. |
| In the Linux kernel, the following vulnerability has been resolved:
net/sched: em_text: reject unterminated algo before autoload
This is a follow-up to commit 9c572a83037a ("net/sched: fix potential
stack infoleak in em_text_dump()"), which zero-initialised the dump-side
struct. Sashiko pointed at a pre-existing bug that exposed the change-side
input-validation gap open.
em_text_change() casts the raw netlink attribute payload to struct
tcf_em_text and passes conf->algo, a 16-byte array with no enforced NUL
terminator, to textsearch_prepare(). On the TS_AUTOLOAD retry
textsearch_prepare() calls request_module("ts_%s", algo); vsnprintf()
walks %s until it finds a NUL, so an algo[] with no NUL reads past the
array into the adjacent struct fields and payload and feeds those bytes
to the usermode helper command line. This is an out-of-bounds read and
a kernel memory disclosure.
Reject the attribute when no NUL exists within TC_EM_TEXT_ALGOSIZ bytes,
matching the check xt_string has had since 3ab720881b6e.
Conditions to recreate the bug:
- CAP_NET_ADMIN on the target netns (namespace-local via unshare -Urn
is enough)
- install clsact on an interface, then add a basic filter with one text
ematch whose algo[] is 16 bytes with no NUL (e.g. "A"*16) and
pattern_len at least 1
- the add fails with -ENOENT and the kernel invokes modprobe with a
module name made of "ts_" plus the 16 bytes and the adjacent payload |
| In the Linux kernel, the following vulnerability has been resolved:
amt: send the relay's General Query directly from the receive path
An skb queued in a qdisc can outlive the tunnel it references
through a raw pointer in skb->cb. For example, with igmp_qrv set
to 1 on the relay a tunnel lives for 135s, so a netem delay of
180s on the amt device outlives it; when the tunnel expires and is
freed, the subsequent dequeue triggers a use-after-free in
amt_dev_xmit().
BUG: KASAN: slab-use-after-free in amt_dev_xmit+0x2763/0x2e20
Call Trace:
amt_dev_xmit+0x2763/0x2e20 [drivers/net/amt.c:1262]
dev_hard_start_xmit+0x22f/0x620
sch_direct_xmit+0x12e/0xac0
netem_dequeue+0x333/0xc50
net_tx_action+0x35c/0xa60
amt_send_igmp_gq() and amt_send_mld_gq() are only called from
amt_request_handler(), inside the rcu_read_lock_bh() section of
amt_rcv(). amt_request_handler() already has the tunnel the query is
for: it found or created it inside that section. Queuing the query with
dev_queue_xmit() only leads back into amt_dev_xmit(), which strips the
Ethernet header and calls amt_send_membership_query() for that tunnel.
Make that call directly from the two senders instead, the same way
amt_send_advertisement() transmits from the receive path. The query
never waits in a qdisc, the tunnel is only dereferenced inside the
RCU section that found or created it, and nothing is stored in
skb->cb, so no lookup or refcount is needed. Remove the query branch
of amt_dev_xmit(), amt_skb_cb() and struct amt_skb_cb, which have no
users left.
Behaviour changes:
- The relay's own General Queries no longer pass through the amt
device's egress path: its qdisc, tc egress (clsact/tcx), the
netfilter egress hook and packet taps. They are still visible as
UDP on the underlay.
- A query that is sent successfully is no longer counted as
tx_dropped. The old query branch left through the unlock label,
which counted every sent query as dropped.
- A query that reaches amt_dev_xmit() on a relay from elsewhere,
such as a userspace querier, is now dropped at the IGMP/MLD type
switch. Before, it trusted whatever skb->cb held, and a NULL
tunnel hit the WARN_ON(1). |
| In the Linux kernel, the following vulnerability has been resolved:
cxgb4/ch_ktls: disable softirqs around tid_list erases
chcr_ktls_cpl_act_open_rpl() inserts into tid_list from the receive path
using xa_insert_bh(). The array is shared by the adapter's connections
and initialized with XA_FLAGS_LOCK_BH. However, chcr_ktls_dev_del() and
the chcr_ktls_dev_add() error path use xa_erase(), which takes the XArray
lock without disabling softirqs.
When cleanup runs with softirqs enabled, a receive softirq for another
connection on the same CPU can interrupt the erase and spin on the lock
held by the interrupted task. Use xa_erase_bh() at both sites to match
the insertion path. |
| In the Linux kernel, the following vulnerability has been resolved:
nvmet: use the local P2P device on metadata allocation failure
nvmet_req_alloc_p2pmem_sgls() assigns req->p2p_dev only after the data
and metadata SGL allocations succeed. If the data allocation succeeds
but the metadata allocation fails, out_free_sg passes req->p2p_dev to
pci_p2pmem_free_sgl() before that assignment has taken place.
Pass the local p2p_dev argument instead, so cleanup uses the same PCI
device as the successful data allocation. |
| In the Linux kernel, the following vulnerability has been resolved:
ASoC: adau1372: allow sleepy powerdown GPIOs
gpiod_set_value() emits a WARN when the GPIO provider indicates that it
can sleep, as is typical for I2C controlled GPIO expanders. Since the
powerdown GPIO is only manipulated in process context, use the _cansleep
variant instead. This lets the driver use sleepy GPIOs to power off the
chip. |
| In the Linux kernel, the following vulnerability has been resolved:
flow_dissector: avoid u16 truncation of skb->len when computing thoff
__skb_flow_dissect() computes key_control->thoff using:
key_control->thoff = min_t(u16, nhoff, skb ? skb->len : hlen);
min_t(u16, ...) casts both arguments to u16 before comparing them.
Whenever skb->len (or hlen) modulo 65536 is smaller than nhoff, the
truncated length wins and thoff is set to a bogus small value, even
when the dissection succeeded. For example, an IPv4/TCP frame with
skb->len == 65540 and nhoff == 34 gets thoff == 4, so callers such as
skb_probe_transport_header() point the transport header inside the
Ethernet header.
Such skbs are not exotic:
- At the time of commit d0c081b49137 ("flow_dissector: properly cap
thoff field"), AF_PACKET with PACKET_VNET_HDR could already build GSO
skbs larger than 64KB (MTU checks are skipped for GSO, and
alloc_skb_with_frags() accepted up to MAX_SKB_FRAGS (17) order-0
pages on top of the linear part).
- BIG TCP now makes skbs larger than 64KB common.
- The following patch makes tun_get_user() dissect IFF_TAP frames
before eth_type_trans() pulls the Ethernet header, so a GSO frame
carrying a 65522..65535 byte L3 packet will be dissected with
skb->len in [65536, 65549].
Compare as u32 instead. If the resulting offset cannot be represented
in the u16 key_control->thoff, cap it to U16_MAX and report the
dissection as failed rather than silently returning a wrong transport
offset. thoff is still set on failure, as some callers (such as
eth_get_headlen()) use it regardless of the return value. |
| In the Linux kernel, the following vulnerability has been resolved:
flow_dissector: avoid u16 truncation of hlen in bpf_flow_dissect()
bpf_flow_dissect() sanitizes the offsets returned by the BPF program
with clamp_t(u16, ..., hlen).
If hlen is bigger than 65535, the upper bound is truncated before
the comparison. For instance, with hlen == 65536, both nhoff and
thoff are forced to zero, even if the program returned sane values.
This is the same class of bug as the one fixed in commit 99bda1ecbd56
("flow_dissector: avoid u16 truncation of skb->len when computing
thoff"). That fix does not cover the BPF path, because
__skb_flow_dissect() returns early when a BPF flow dissector
handles the packet.
struct bpf_flow_keys stores nhoff and thoff as u16, so cap hlen
to U16_MAX before clamping.
Found by sashiko while reviewing the commit above. |
| In the Linux kernel, the following vulnerability has been resolved:
HID: steam: Refactor registration
This refactors and simplifies the registration/unregistration flow. Since
we now only perform registration when the client isn't opened anymore, the
logic for handling that can be removed, and the rest of the function
streamlined.
We also remove the previous assumption that we have a serial number to show
we're registered, replacing it with a single purpose boolean.
In a previous refactor the code for unregistering a battery if later
registration steps failed was accidentally left out. As a result, a
lingering power_supply object could get left over after the steam object
was torn down. This is also fixed here. |
| In the Linux kernel, the following vulnerability has been resolved:
ASoC: qcom: lpass-cpu: use DAI table index for playback constraints
The DAI ID is a hardware port ID and is not necessarily the index of
the corresponding entry in variant->dai_driver.
When configuring a DAI with LPAIF_I2SCTL_MODE_QUAD01, the probe code
currently uses dai_id to index variant->dai_driver. This is incorrect
for platforms where DAI IDs are sparse. For example, the IPQ806x MI2S
DAI has ID 4 while it is the only entry in the DAI driver table. If
that DAI is configured for QUAD01 and probe reaches this branch, the
code writes beyond that single entry via dai_driver[4] instead of
updating the DAI being processed.
Use the loop index i when updating the current DAI's playback channel
constraints, while retaining dai_id for indexing the hardware-port
specific playback SD-line mode array.
This fixes the incorrect DAI table access for platforms where the DAI
ID does not match its position in the driver table. |
| In the Linux kernel, the following vulnerability has been resolved:
wifi: ath11k: reset ar->num_stations on hardware start
When (multiple) hw restart occurs, we end up in a situation where we
cannot accept new stations / mesh peers. This seems to be the
'num_stations' in 'struct ath11k' that did not get reset properly in
this case. In ath11k_mac_op_start(), it was indeed the only accounting var
that did not get reset so let's clear it too.
This avoids problems like those:
[1248828.088023] WARNING: CPU: 0 PID: 12281 at net/mac80211/util.c:1682 ieee80211_reconfig_stations+0x98/0xc0
[1248828.088115] Call trace:
[1248828.088116] ieee80211_reconfig_stations+0x98/0xc0 (P)
[1248828.088119] ieee80211_reconfig+0x774/0x1438
[1248828.088123] ieee80211_restart_work+0x10c/0x178
[1248828.088127] process_one_work+0x178/0x3c0
[1248828.088130] worker_thread+0x280/0x440
[1248828.088133] kthread+0xe0/0xf8
[1248828.088137] ret_from_fork+0x10/0x20
[1248828.088141] ---[ end trace 0000000000000000 ]---
[1248836.686604] ath11k_pci 0000:04:00.0: refusing to associate station: too many connected already (128)
[1248836.686609] ath11k_pci 0000:04:00.0: Failed to add station: xx:xx:xx:xx:xx:xx for VDEV: 1
Tested-on: QCN9074 hw1.0 PCI WLAN.HK.2.9.0.1-01977-QCAHKSWPL_SILICONZ-1 |
| In the Linux kernel, the following vulnerability has been resolved:
rtc: dev: zero-initialize struct rtc_wkalrm to prevent information leak
The struct rtc_wkalrm has padding holes after the 'pending' member.
When returned to userspace via the RTC_WKALRM_RD ioctl, uninitialized
kernel stack data residing in these holes may be leaked.
Zero-initialize the struct at declaration to eliminate this information
leak risk.
Fixes smatch warnings:
- drivers/rtc/dev.c:392 rtc_dev_ioctl() warn: check that 'alarm' doesn't
leak information (struct has a hole after 'pending') |
| In the Linux kernel, the following vulnerability has been resolved:
ipv6: sr: use skb_get_hash_net() in seg6_make_flowlabel()
Since commit d58e468b1112 ("flow_dissector: implements flow dissector
BPF hook") __skb_flow_dissect() needs a net pointer, either from
skb->dev, skb->sk, or since commit 3cbf4ffba5ee ("net: plumb network
namespace into __skb_flow_dissect") a caller provided pointer.
syzbot was able to reach seg6_make_flowlabel() with an skb having
neither skb->dev nor skb->sk set: a TIPC UDP bearer sends a discovery
message through an IPv4 route using seg6 encap, while
net.ipv6.seg6_flowlabel is set to 1.
seg6_make_flowlabel() already has a net pointer, use skb_get_hash_net().
WARNING: net/core/flow_dissector.c:1131 at __skb_flow_dissect+0x910/0x5368 net/core/flow_dissector.c:1126, CPU#0: syz.0.17/4930
Call trace:
__skb_flow_dissect+0x910/0x5368 net/core/flow_dissector.c:1126 (P)
__skb_get_hash_net+0xe0/0x29c net/core/flow_dissector.c:1903
skb_get_hash include/linux/skbuff.h:1663 [inline]
seg6_make_flowlabel+0xcc/0x1ec net/ipv6/seg6_iptunnel.c:132
__seg6_do_srh_encap+0x320/0xbf4 net/ipv6/seg6_iptunnel.c:161
seg6_do_srh+0x4b4/0xa44 net/ipv6/seg6_iptunnel.c:431
seg6_output_core+0x164/0x688 net/ipv6/seg6_iptunnel.c:681
seg6_output+0x44/0x1ac net/ipv6/seg6_iptunnel.c:744
lwtunnel_output+0x3d0/0x664 net/core/lwtunnel.c:356
dst_output include/net/dst.h:470 [inline]
ip_local_out+0x110/0x148 net/ipv4/ip_output.c:131
iptunnel_xmit+0x50c/0xd38 net/ipv4/ip_tunnel_core.c:97
udp_tunnel_xmit_skb+0x220/0x348 net/ipv4/udp_tunnel_core.c:187
tipc_udp_xmit+0x75c/0x9c0 net/tipc/udp_media.c:202
tipc_udp_send_msg+0x214/0x374 net/tipc/udp_media.c:274
tipc_bearer_xmit_skb+0x260/0x3b0 net/tipc/bearer.c:576
tipc_enable_bearer net/tipc/bearer.c:366 [inline]
__tipc_nl_bearer_enable+0xc90/0xfb0 net/tipc/bearer.c:1048
tipc_nl_bearer_enable+0x2c/0x48 net/tipc/bearer.c:1057
genl_family_rcv_msg_doit+0x1e4/0x2d4 net/netlink/genetlink.c:1114 |
| In the Linux kernel, the following vulnerability has been resolved:
usb: hub: use shorter 120ms post resume hold for SS root hubs
Holding a USB3 hub PM runtime reference for 200ms at hub resume triggers
an AMD platform issue. Users running Android adb report crashes after
adb has been polling and waking up the USB subsystem once a second for
some time. Vendors are working on a solution. Disabling USB runtime PM
is one way to prevent this issue, but it is also proven that reducing the
hold time to 120ms in resume also mitigates it. See Link for more
details.
Reducing the hold time to 120ms for the USB3 roothub is in itself a valid
change and optimization, as the current 200ms is excessive: a root hub
has no upstream suspended hub whose wake propagation needs to be
accounted for, but still need some time for USB3 link training to
complete.
Keep the 200ms hold for external hubs that commit 8f5b7e2bec1c
("usb: hub: fix detection of high tier USB3 devices behind suspended
hubs") is intended for. |
| In the Linux kernel, the following vulnerability has been resolved:
mtd: spinand: fix NULL pointer dereference with no ECC engine
When "nand-no-ecc-engine" is set in DT, nanddev_get_ecc_engine() takes
the NAND_ECC_ENGINE_TYPE_NONE path and returns success while leaving
nand->ecc.engine NULL. The SPI-NAND code nevertheless dereferences it
unconditionally to test for a pipelined engine, so probing such a
device oopses immediately.
Rather than open-coding the test three times, add a
nand_ecc_is_pipelined() helper to the NAND core that folds the NULL
check into the integration comparison, and use it everywhere. Future
callers then cannot reintroduce the problem. |
