| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| In the Linux kernel, the following vulnerability has been resolved:
netfilter: bridge: fix stale prevhdr pointer in br_ip6_fragment()
br_ip6_fragment() gets prevhdr, a pointer into the skb head, from
ip6_find_1stfragopt(), then calls skb_checksum_help(). For a cloned skb
skb_checksum_help() reallocates the head via pskb_expand_head(), leaving
prevhdr dangling. It is later dereferenced in ip6_frag_next(), causing a
use-after-free write.
Save prevhdr's offset before skb_checksum_help() and recompute it after,
like commit ef0efcd3bd3f ("ipv6: Fix dangling pointer when ipv6
fragment").
BUG: KASAN: slab-use-after-free in ip6_frag_next (net/ipv6/ip6_output.c:857)
Write of size 1 at addr ffff888013ff5016 by task exploit/141
Call Trace:
...
kasan_report (mm/kasan/report.c:595)
ip6_frag_next (net/ipv6/ip6_output.c:857)
br_ip6_fragment (net/ipv6/netfilter.c:212)
nf_ct_bridge_post (net/bridge/netfilter/nf_conntrack_bridge.c:407)
nf_hook_slow (net/netfilter/core.c:619)
br_forward_finish (net/bridge/br_forward.c:66)
__br_forward (net/bridge/br_forward.c:115)
maybe_deliver (net/bridge/br_forward.c:191)
br_flood (net/bridge/br_forward.c:245)
br_handle_frame_finish (net/bridge/br_input.c:229)
br_handle_frame (net/bridge/br_input.c:442)
...
packet_sendmsg (net/packet/af_packet.c:3114)
...
do_syscall_64 (arch/x86/entry/syscall_64.c:94)
entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121)
Kernel panic - not syncing: Fatal exception in interrupt |
| In the Linux kernel, the following vulnerability has been resolved:
tipc: fix use-after-free of the discoverer in tipc_disc_rcv()
bearer_disable() frees b->disc with tipc_disc_delete()'s plain kfree(),
but tipc_disc_rcv() still dereferences b->disc in RX softirq under
rcu_read_lock() (tipc_udp_recv -> tipc_rcv -> tipc_disc_rcv).
L2 bearers are safe thanks to the synchronize_net() in
tipc_disable_l2_media(), but the UDP bearer defers that call to the
cleanup_bearer() workqueue, so the discoverer is freed with no grace
period:
BUG: KASAN: slab-use-after-free in tipc_disc_rcv (net/tipc/discover.c:149)
Read of size 8 at addr ffff88802348b728 by task poc_tipc/184
<IRQ>
tipc_disc_rcv (net/tipc/discover.c:149)
tipc_rcv (net/tipc/node.c:2126)
tipc_udp_recv (net/tipc/udp_media.c:391)
udp_rcv (net/ipv4/udp.c:2643)
ip_local_deliver_finish (net/ipv4/ip_input.c:241)
</IRQ>
Freed by task 181:
kfree (mm/slub.c:6565)
bearer_disable (net/tipc/bearer.c:418)
tipc_nl_bearer_disable (net/tipc/bearer.c:1001)
The bearer is freed with kfree_rcu(); free the discoverer the same way.
Add an rcu_head to struct tipc_discoverer and free it and its skb from an
RCU callback.
Because the RCU callback (tipc_disc_free_rcu) lives in module text, a
call_rcu() that is still pending when the tipc module is unloaded would
invoke a freed function. Add an rcu_barrier() to tipc_exit() after the
bearer subsystem has been torn down, so all pending discoverer callbacks
have run before the module text goes away.
Reachable from an unprivileged user namespace: the TIPCv2 genl family is
netnsok and its bearer commands have no GENL_ADMIN_PERM. Needs CONFIG_TIPC
and CONFIG_TIPC_MEDIA_UDP. |
| In the Linux kernel, the following vulnerability has been resolved:
net/smc: fix UAF in smc_cdc_rx_handler() by pinning the socket
smc_cdc_rx_handler() looks up the connection by token under the link
group's conns_lock, drops the lock, and then dereferences conn and the
smc_sock derived from it, ending in sock_hold(&smc->sk) inside
smc_cdc_msg_recv(). No reference is held across the lock release.
The only reference pinning the socket while the connection is
discoverable in the link group is taken in smc_lgr_register_conn()
(sock_hold) and dropped in __smc_lgr_unregister_conn() (sock_put), both
under conns_lock. Once the handler drops conns_lock, a concurrent
close() -> smc_release() -> smc_conn_free() -> smc_lgr_unregister_conn()
can drop that reference and free the smc_sock, so the handler's later
sock_hold() runs on freed memory:
WARNING: lib/refcount.c:25 at refcount_warn_saturate
Workqueue: rxe_wq do_work
refcount_warn_saturate (lib/refcount.c:25)
smc_cdc_msg_recv (net/smc/smc_cdc.c:430)
smc_cdc_rx_handler (net/smc/smc_cdc.c:502)
smc_wr_rx_tasklet_fn (net/smc/smc_wr.c:445)
tasklet_action_common (kernel/softirq.c:938)
handle_softirqs (kernel/softirq.c:622)
Kernel panic - not syncing: panic_on_warn set
Only SMC-R is affected. The SMC-D receive tasklet is stopped by
tasklet_kill(&conn->rx_tsklet) in smc_conn_free() before the connection
is unregistered, so it cannot run concurrently with the free.
Take the socket reference while still holding conns_lock, so the
registration reference can no longer be the last one, and drop it once
the handler is done. |
| In the Linux kernel, the following vulnerability has been resolved:
net/sched: cls_api: Handle TC_ACT_CONSUMED in tcf_qevent_handle
tcf_classify() can return TC_ACT_CONSUMED while the skb is held by the
defragmentation engine (e.g. act_ct on out-of-order fragments). When
that happens the skb is no longer owned by the caller and must not be
touched again.
tcf_qevent_handle() did not handle TC_ACT_CONSUMED: it fell through the
switch and returned the skb to the caller as if classification had
passed. The only qdisc that wires up qevents today is RED, via three call sites
(qe_mark on RED_PROB_MARK/HARD_MARK, qe_early_drop on congestion_drop)
red_enqueue() was continuing to operate on an skb it no longer owns in this
case -- enqueueing it, dropping it, or updating statistics. Resulting in a UAF.
tc qdisc add dev eth0 root handle 1: red ... qevent early_drop block 10
tc filter add block 10 ... action ct
(with ct defrag enabled and traffic that produces out-of-order
fragments, e.g. a fragmented UDP stream)
Handle TC_ACT_CONSUMED in tcf_qevent_handle() the same way the ingress
and egress fast paths do: treat it as stolen and return NULL without
touching the skb. Unlike the TC_ACT_STOLEN case, the skb must not be
dropped/freed here, as it is no longer owned by us. |
| In the Linux kernel, the following vulnerability has been resolved:
mfd: cros_ec: Delay dev_set_drvdata() until probe success
If ec_device_probe() fails, cros_ec_class_release releases memory for the
cros_ec_dev structure. However, because the drvdata was already set,
sub-drivers like cros_ec_typec can still retrieve the stale pointer via the
platform device. This leads to a use-after-free when cros_ec_typec attempts
to access &typec->ec->ec->dev on a device that has already been released.
Move dev_set_drvdata() to ensure that the pointer is only made available
once all initialization steps have succeeded.
sysfs: cannot create duplicate filename '/class/chromeos/cros_ec'
Call trace:
sysfs_do_create_link_sd+0x94/0xdc
sysfs_create_link+0x30/0x44
device_add_class_symlinks+0x90/0x13c
device_add+0xf0/0x50c
ec_device_probe+0x150/0x4f0
platform_probe+0xa0/0xe0
...
BUG: KASAN: invalid-access in __memcpy+0x44/0x230
Write at addr f5ffff809e2d33ac by task kworker/u32:5/125
Pointer tag: [f5], memory tag: [fe]
Tainted : [W]=WARN, [O]=OOT_MODULE
Hardware name: Google Navi unprovisioned 0x7FFFFFFF/sku0 board/sku3
Workqueue: events_unbound deferred_probe_work_func
Call trace:
__memcpy+0x44/0x230
cros_ec_check_features+0x60/0xcc [cros_ec_proto]
cros_typec_probe+0xe8/0x6e0 [cros_ec_typec]
platform_probe+0xa0/0xe0 |
| In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: bnep: pin L2CAP connection during netdev registration
bnep_add_connection() reads the L2CAP connection without holding the
channel lock, then passes its HCI device to register_netdev(). Controller
teardown can clear and release that connection concurrently, leaving the
network device registration path to dereference a freed parent device.
Take a reference to the L2CAP connection while holding the channel lock.
Retain it until register_netdev() has taken the parent device reference. |
| In the Linux kernel, the following vulnerability has been resolved:
fuse: re-lock request before returning from fuse_ref_folio()
fuse_ref_folio() unlocks the request but does not re-lock it before
returning. fuse_chan_abort() can end the request and the async end
callback (eg fuse_writepage_free()) can free the args while the
subsequent copy chain logic after fuse_ref_folio() accesses them,
leading to use-after-free issues.
Fix this by locking the request in fuse_ref_folio() before returning. |
| In the Linux kernel, the following vulnerability has been resolved:
mm/debug_vm_pgtable: clear page table entries at destroy_args()
The mm/debug_vm_pagetable test allocates manually page table entries for
the tests it runs, using also its manually allocated mm_struct. That in
itself is ok, but when it exits, at destroy_args() it fails to clear those
entries with the *_clear functions.
The problem is that leaves stale entries. If another process allocates an
mm_struct with a pgd at the same address, it may end up running into the
stale entry. This is happening in practice on a debug kernel with
CONFIG_DEBUG_VM_PGTABLE=y, for example this is the output with some extra
debugging I added (it prints a warning trace if pgtables_bytes goes
negative, in addition to the warning at check_mm() function):
[ 2.539353] debug_vm_pgtable: [get_random_vaddr ]: random_vaddr is 0x7ea247140000
[ 2.539366] kmem_cache info
[ 2.539374] kmem_cachep 0x000000002ce82385 - freelist 0x0000000000000000 - offset 0x508
[ 2.539447] debug_vm_pgtable: [init_args ]: args->mm is 0x000000002267cc9e
(...)
[ 2.552800] WARNING: CPU: 5 PID: 116 at include/linux/mm.h:2841 free_pud_range+0x8bc/0x8d0
[ 2.552816] Modules linked in:
[ 2.552843] CPU: 5 UID: 0 PID: 116 Comm: modprobe Not tainted 6.12.0-105.debug_vm2.el10.ppc64le+debug #1 VOLUNTARY
[ 2.552859] Hardware name: IBM,9009-41A POWER9 (architected) 0x4e0202 0xf000005 of:IBM,FW910.00 (VL910_062) hv:phyp pSeries
[ 2.552872] NIP: c0000000007eef3c LR: c0000000007eef30 CTR: c0000000003d8c90
[ 2.552885] REGS: c0000000622e73b0 TRAP: 0700 Not tainted (6.12.0-105.debug_vm2.el10.ppc64le+debug)
[ 2.552899] MSR: 800000000282b033 <SF,VEC,VSX,EE,FP,ME,IR,DR,RI,LE> CR: 24002822 XER: 0000000a
[ 2.552954] CFAR: c0000000008f03f0 IRQMASK: 0
[ 2.552954] GPR00: c0000000007eef30 c0000000622e7650 c000000002b1ac00 0000000000000001
[ 2.552954] GPR04: 0000000000000008 0000000000000000 c0000000007eef30 ffffffffffffffff
[ 2.552954] GPR08: 00000000ffff00f5 0000000000000001 0000000000000048 0000000000004000
[ 2.552954] GPR12: 00000003fa440000 c000000017ffa300 c0000000051d9f80 ffffffffffffffdb
[ 2.552954] GPR16: 0000000000000000 0000000000000008 000000000000000a 60000000000000e0
[ 2.552954] GPR20: 4080000000000000 c0000000113af038 00007fffcf130000 0000700000000000
[ 2.552954] GPR24: c000000062a6a000 0000000000000001 8000000062a68000 0000000000000001
[ 2.552954] GPR28: 000000000000000a c000000062ebc600 0000000000002000 c000000062ebc760
[ 2.553170] NIP [c0000000007eef3c] free_pud_range+0x8bc/0x8d0
[ 2.553185] LR [c0000000007eef30] free_pud_range+0x8b0/0x8d0
[ 2.553199] Call Trace:
[ 2.553207] [c0000000622e7650] [c0000000007eef30] free_pud_range+0x8b0/0x8d0 (unreliable)
[ 2.553229] [c0000000622e7750] [c0000000007f40b4] free_pgd_range+0x284/0x3b0
[ 2.553248] [c0000000622e7800] [c0000000007f4630] free_pgtables+0x450/0x570
[ 2.553274] [c0000000622e78e0] [c0000000008161c0] exit_mmap+0x250/0x650
[ 2.553292] [c0000000622e7a30] [c0000000001b95b8] __mmput+0x98/0x290
[ 2.558344] [c0000000622e7a80] [c0000000001d1018] exit_mm+0x118/0x1b0
[ 2.558361] [c0000000622e7ac0] [c0000000001d141c] do_exit+0x2ec/0x870
[ 2.558376] [c0000000622e7b60] [c0000000001d1ca8] do_group_exit+0x88/0x150
[ 2.558391] [c0000000622e7bb0] [c0000000001d1db8] sys_exit_group+0x48/0x50
[ 2.558407] [c0000000622e7be0] [c00000000003d810] system_call_exception+0x1e0/0x4c0
[ 2.558423] [c0000000622e7e50] [c00000000000d05c] system_call_vectored_common+0x15c/0x2ec
(...)
[ 2.558892] ---[ end trace 0000000000000000 ]---
[ 2.559022] BUG: Bad rss-counter state mm:000000002267cc9e type:MM_ANONPAGES val:1
[ 2.559037] BUG: non-zero pgtables_bytes on freeing mm: -6144
Here the modprobe process ended up with an allocated mm_struct from the
mm_struct slab that was used before by the debug_vm_pgtable test. That is
not a problem, since the mm_stru
---truncated--- |
| In the Linux kernel, the following vulnerability has been resolved:
ftrace: Also allocate and copy hash for reading of filter files
Currently the reader of set_ftrace_filter and set_ftrace_notrace just adds
the pointer to the global tracer hash to its iterator. Unlike the writer
that allocates a copy of the hash, the reader keeps the pointer to the
filter hashes. This is problematic because this pointer is static across
function calls that release the locks that can update the global tracer
hashes. This can cause UAF and similar bugs.
Allocate and copy the hash for reading the filter files like it is done
for the writers. This not only fixes UAF bugs, but also makes the code a
bit simpler as it doesn't have to differentiate when to free the
iterator's hash between writers and readers. |
| In the Linux kernel, the following vulnerability has been resolved:
ice: fix NULL access of tx->in_use in ice_ptp_ts_irq
The E810 device has support for a "low latency" firmware interface to
access and read the Tx timestamps. This interface does not use the standard
Tx timestamp logic, due to the latency overhead of proxying sideband
command requests over the firmware AdminQ.
The logic still makes use of the Tx timestamp tracking structure,
ice_ptp_tx, as it uses the same "ready" bitmap to track which Tx
timestamps complete.
Unfortunately, the ice_ptp_ts_irq() function does not check if the tracker
is initialized before its first access. This results in NULL dereference or
use-after-free bugs similar to the following:
[245977.278756] BUG: kernel NULL pointer dereference, address: 0000000000000000
[245977.278774] RIP: 0010:_find_first_bit+0x19/0x40
[245977.278796] Call Trace:
[245977.278809] ? ice_misc_intr+0x364/0x380 [ice]
This can occur if a Tx timestamp interrupt races with the driver reset
logic.
Fix this by only checking the in_use bitmap (and other fields) if the
tracker is marked as initialized. The reset flow will clear the init field
under lock before it tears the tracker down, thus preventing any
use-after-free or NULL access. |
| In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: Fix use-after-free in l2cap_sock_cleanup_listen()
syzbot reported the splat below without a repro.
In the splat, a single thread calling bt_accept_dequeue() freed sk
and touched it after that.
The root cause would be the racy l2cap_sock_cleanup_listen() call
added by the cited commit.
bt_accept_dequeue() is called under lock_sock() except for
l2cap_sock_release().
Two threads could see the same socket during the list iteration
in bt_accept_dequeue():
CPU1 CPU2 (close())
---- ----
sock_hold(sk) sock_hold(sk);
lock_sock(sk) <-- block close()
sock_put(sk)
bt_accept_unlink(sk)
sock_put(sk) <-- refcnt by bt_accept_enqueue()
release_sock(sk)
lock_sock(sk)
sock_put(sk)
bt_accept_unlink(sk)
sock_put(sk) <-- last refcnt
bt_accept_unlink(sk) <-- UAF
Depending on the timing, the other thread could show up in the
"Freed by task" part.
Let's call l2cap_sock_cleanup_listen() under lock_sock() in
l2cap_sock_release().
[0]:
BUG: KASAN: slab-use-after-free in debug_spin_lock_before kernel/locking/spinlock_debug.c:86 [inline]
BUG: KASAN: slab-use-after-free in do_raw_spin_lock+0x26f/0x2b0 kernel/locking/spinlock_debug.c:115
Read of size 4 at addr ffff88803b7eb1c4 by task syz.5.3276/16995
CPU: 3 UID: 0 PID: 16995 Comm: syz.5.3276 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:378 [inline]
print_report+0xcd/0x630 mm/kasan/report.c:482
kasan_report+0xe0/0x110 mm/kasan/report.c:595
debug_spin_lock_before kernel/locking/spinlock_debug.c:86 [inline]
do_raw_spin_lock+0x26f/0x2b0 kernel/locking/spinlock_debug.c:115
spin_lock_bh include/linux/spinlock.h:356 [inline]
release_sock+0x21/0x220 net/core/sock.c:3746
bt_accept_dequeue+0x505/0x600 net/bluetooth/af_bluetooth.c:312
l2cap_sock_cleanup_listen+0x5c/0x2a0 net/bluetooth/l2cap_sock.c:1451
l2cap_sock_release+0x5c/0x210 net/bluetooth/l2cap_sock.c:1425
__sock_release+0xb3/0x270 net/socket.c:649
sock_close+0x1c/0x30 net/socket.c:1439
__fput+0x3ff/0xb70 fs/file_table.c:468
task_work_run+0x14d/0x240 kernel/task_work.c:227
resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
exit_to_user_mode_loop+0xeb/0x110 kernel/entry/common.c:43
exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
do_syscall_64+0x3f6/0x4c0 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f2accf8ebe9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffdb6cb1378 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00000000000426fb RCX: 00007f2accf8ebe9
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007f2acd1b7da0 R08: 0000000000000001 R09: 00000012b6cb166f
R10: 0000001b30e20000 R11: 0000000000000246 R12: 00007f2acd1b609c
R13: 00007f2acd1b6090 R14: ffffffffffffffff R15: 00007ffdb6cb1490
</TASK>
Allocated by task 5326:
kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
kasan_save_track+0x14/0x30 mm/kasan/common.c:68
poison_kmalloc_redzone mm/kasan/common.c:388 [inline]
__kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:405
kasan_kmalloc include/linux/kasan.h:260 [inline]
__do_kmalloc_node mm/slub.c:4365 [inline]
__kmalloc_nopro
---truncated--- |
| When copying knotes from a parent kqueue to a child, the copy code did not correctly exclude marker knotes (used internally to track list traversal position) before marking them as in-flux and releasing the kqueue lock. If another thread freed a marker while the lock was dropped, the subsequent in-flux decrement operated on freed memory.
An unprivileged local user may be able to exploit these races to escalate privileges. |
| In the Linux kernel, the following vulnerability has been resolved:
mac802154: llsec: add skb_cow_data() before in-place crypto
llsec_do_encrypt_unauth(), llsec_do_encrypt_auth(),
llsec_do_decrypt_unauth(), and llsec_do_decrypt_auth() all perform
in-place cryptographic transformations on skb data. They build a
scatterlist with sg_init_one() pointing into the skb's linear data area
and then pass the same scatterlist as both src and dst to the crypto API
(e.g. crypto_skcipher_encrypt/decrypt, crypto_aead_encrypt/decrypt).
On the RX path, __ieee802154_rx_handle_packet() clones the received skb
before handing it to each subscriber via ieee802154_subif_frame(). The
cloned skb shares the same underlying data buffer via reference
counting. When llsec_do_decrypt() subsequently modifies this shared
buffer in place, it corrupts data that other clones -- potentially
belonging to other sockets or subsystems -- still reference.
On the TX path, similar data sharing can occur when an skb's head has
been cloned (skb_cloned() returns true).
The fix is to call skb_cow_data() before performing any in-place crypto
operation. skb_cow_data() ensures that the skb's data area is not
shared: if the skb head is cloned or the data spans multiple fragments,
it copies the data into a private buffer that can be safely modified in
place. This is the same pattern used by:
- ESP (net/ipv4/esp4.c, net/ipv6/esp6.c)
- MACsec (drivers/net/macsec.c)
- WireGuard (drivers/net/wireguard/receive.c)
- TIPC (net/tipc/crypto.c)
Without this guard, in-place crypto on shared skb data leads to:
- Silent data corruption of other skb clones
- Use-after-free when the crypto API scatterwalk writes through a
page that has already been freed by another clone's kfree_skb()
- Kernel crashes under concurrent 802.15.4 traffic with security
enabled (KASAN/KMSAN reports slab-use-after-free)
Found by 0sec (https://0sec.ai) using automated source analysis. |
| In the Linux kernel, the following vulnerability has been resolved:
exfat: fix potential use-after-free in exfat_find_dir_entry()
In exfat_find_dir_entry(), the buffer_head obtained from
exfat_get_dentry() is released with brelse(bh) before the fall-through
TYPE_EXTEND branch reads the directory entry through ep (which points
into bh->b_data):
brelse(bh);
if (entry_type == TYPE_EXTEND) {
...
len = exfat_extract_uni_name(ep, entry_uniname);
...
}
After brelse() drops our reference, nothing guarantees that the
underlying page backing bh->b_data remains valid for the subsequent
exfat_extract_uni_name() read. This is the same pattern fixed in
commit fc961522ddbd ("exfat: Fix potential use after free in
exfat_load_upcase_table()").
Move brelse(bh) so it runs after ep is no longer dereferenced on
each branch.
Confirmed on QEMU x86_64 with CONFIG_KASAN=y + CONFIG_DEBUG_PAGEALLOC=y
+ CONFIG_PAGE_POISONING=y on linux-next, using a crafted exFAT image
(long filename with same-hash collisions forcing the TYPE_EXTEND path).
With a debug-only invalidate_bdev() inserted between brelse(bh) and
the ep read to make the stale-deref window deterministic, the
unpatched kernel faults:
BUG: KASAN: use-after-free in exfat_find_dir_entry+0x133b/0x15a0
BUG: unable to handle page fault for address: ffff88801a5fa0c2
Oops: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN NOPTI
RIP: 0010:exfat_find_dir_entry+0x1188/0x15a0
With this patch applied, the same instrumented harness completes
cleanly under the same sanitizer stack. I have not reproduced a
crash on an uninstrumented kernel under ordinary reclaim; the
instrumented A/B establishes the lifetime violation and that the
patch closes it, not an unaided triggerability claim. |
| In the Linux kernel, the following vulnerability has been resolved:
hdlc_ppp: sync per-proto timers before freeing hdlc state
Each PPP control protocol (LCP/IPCP/IPV6CP) embedded in struct ppp
registers a timer via timer_setup(). That struct ppp is the
hdlc->state allocation, which detach_hdlc_protocol() frees with kfree()
in both teardown paths: unregister_hdlc_device() and the re-attach inside
attach_hdlc_protocol().
The ppp proto never registered a .detach callback, so
detach_hdlc_protocol() performs no timer synchronization before the
kfree(). The only cancel, timer_delete(&proto->timer) in ppp_cp_event(),
is partial (it does not wait for a running callback) and only runs on the
->CLOSED transition; ppp_stop()/ppp_close() do not sync either. A
ppp_timer callback already executing (blocked on ppp->lock) survives the
kfree and then dereferences proto->state / ppp->lock in freed memory,
leading to a use-after-free.
Fix this by adding a .detach helper that calls timer_shutdown_sync() on
every per-proto timer. detach_hdlc_protocol() invokes proto->detach(dev)
before kfree(hdlc->state), so timer_shutdown_sync()
now runs on both free paths.
timer_shutdown_sync() is used instead of timer_delete_sync() because the
keepalive path re-arms the timer through add_timer()/mod_timer() and
shutdown blocks any re-activation during teardown.
Initialize the per-protocol timers in ppp_ioctl() when the protocol is
attached, and remove the now-redundant timer_setup() from ppp_start(), so
that the timers are initialized exactly once at attach time and
ppp_timer_release() never operates on uninitialized timer_list
structures. attach_hdlc_protocol() uses kmalloc() (not kzalloc), so
struct ppp's protos[i].timer is uninitialized garbage until the first
timer_setup(); without this init-at-attach, attaching the PPP protocol
without ever bringing the device up would leave timer_shutdown_sync()
operating on uninitialized memory in .detach. Moving the init out of
ppp_start() (which only runs on NETDEV_UP) into the attach path makes the
initialization unconditional and avoids initializing the same timer_list
twice.
This bug was found by static analysis. |
| In the Linux kernel, the following vulnerability has been resolved:
blk-cgroup: fix UAF in __blkcg_rstat_flush()
When multiple blkgs in the same blkcg are released concurrently,
a use-after-free can occur. The race happens when one blkg's
__blkcg_rstat_flush() removes another blkg's iostat entries via
llist_del_all(). The second blkg sees an empty list and proceeds
to free itself while the first is still iterating over its entries.
Move the flush from __blkg_release() (RCU callback) to blkg_release()
(before call_rcu). This ensures the RCU grace period waits for any
concurrent flush's rcu_read_lock() section to complete before freeing. |
| In the Linux kernel, the following vulnerability has been resolved:
pNFS: Fix use-after-free in pnfs_update_layout()
When hitting the NFS_LAYOUT_RETURN branch in pnfs_update_layout(),
the code calls pnfs_prepare_to_retry_layoutget(lo). If it succeeds,
pnfs_put_layout_hdr(lo) is called before trace_pnfs_update_layout(),
which still references 'lo'. This results in a use-after-free when the
tracepoint accesses lo's fields.
Fix this by moving the tracepoint call before pnfs_put_layout_hdr(lo). |
| In the Linux kernel, the following vulnerability has been resolved:
9p: avoid putting oldfid in p9_client_walk() error path
When p9_client_walk() is called with clone set to false, fid aliases
oldfid. If the walk subsequently fails after the request has been sent,
the error path jumps to clunk_fid, which currently calls p9_fid_put(fid)
unconditionally.
This drops a reference to oldfid even though ownership of oldfid remains
with the caller. If this is the last reference, oldfid can be clunked and
destroyed while the caller still expects it to be valid. A later use or
put of oldfid can then trigger a use-after-free or refcount underflow.
Fix this by only putting fid in the clunk_fid error path when it does not
alias oldfid, matching the existing guard in the error path below.
This can be triggered when a multi-component walk is split into multiple
p9_client_walk() calls and a later non-cloning walk fails. A reproducer
and refcount warning logs are available on request. |
| In the Linux kernel, the following vulnerability has been resolved:
serial: 8250_dw: unregister 8250 port if clk_notifier_register() fails
dw8250_probe() registers the 8250 port via serial8250_register_8250_port()
and then, if the device has a clock, registers a clock notifier. If
clk_notifier_register() fails, probe returns the error but leaves the
8250 port registered. The matching serial8250_unregister_port() lives
in dw8250_remove(), which is not called when probe fails, so the port
slot stays occupied until the device is rebound or the system is
rebooted. The devm-allocated driver data is freed while the port still
references it (via the saved private_data and serial_in/serial_out
callbacks), so any access to that port slot before a rebind is a
use-after-free hazard.
Unregister the port on the clk_notifier_register() error path. |
| In the Linux kernel, the following vulnerability has been resolved:
virtiofs: fix UAF on submount umount
iput() called from fuse_release_end() can Oops if the super block has
already been destroyed. Normally this is prevented by waiting for
num_waiting to go down to zero before commencing with super block shutdown.
This only works, however, for the last submount instance, as the wait
counter is per connection, not per superblock.
Revert to using synchronous release requests for the auto_submounts case,
which is virtiofs only at this time. |
