| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| In the Linux kernel, the following vulnerability has been resolved:
USB: serial: keyspan_pda: fix information leak
The write() callback is supposed to return the number of characters
accepted or a negative errno. Since the addition of write fifo support
the keyspan_pda implementation will however return the number characters
submitted to the device if the write urb is not already in use. If this
number is larger than the number of characters passed to write(), the
line discipline continues writing data from beyond the tty write buffer.
Fix the information leak by making sure that keyspan_pda_write_start()
returns zero on success as intended. |
| In the Linux kernel, the following vulnerability has been resolved:
usb: mtu3: unmap request DMA on queue failure
mtu3_gadget_queue() maps the request before checking whether
the QMU GPD ring can accept another transfer. the request is
returned with -EAGAIN before it is linked on the endpoint
request list if mtu3_prepare_transfer() fails.
Normal completion and dequeue paths unmap requests from
mtu3_req_complete(), but this error path never reaches that
helper, so the DMA mapping is left active. Unmap the request
before returning from the failed queue path. |
| In the Linux kernel, the following vulnerability has been resolved:
USB: idmouse: fix use-after-free on disconnect race
mutex_unlock() may access the mutex structure after releasing the lock
and therefore cannot be used to manage lifetime of objects directly
(unlike spinlocks and refcounts). [1][2]
Use a kref to release the driver data to avoid use-after-free in
mutex_unlock() when release() races with disconnect().
[1] a51749ab34d9 ("locking/mutex: Document that mutex_unlock() is
non-atomic")
[2] 2b9d9e0a9ba0 ("locking/mutex: Clarify that mutex_unlock(), and most
other sleeping locks, can still use the lock object
after it's unlocked") |
| In the Linux kernel, the following vulnerability has been resolved:
usb: gadget: udc: Fix use-after-free in gadget_match_driver
The udc structure acts as the management structure for the gadget,
but their lifecycles are decoupled. A race condition exists where
usb_del_gadget() frees the udc memory (e.g., via mode-switch work)
while gadget_match_driver() concurrently accesses the freed udc memory
(e.g., via configfs), causing a Use-After-Free (UAF) that triggers a
NULL pointer dereference when the freed memory is zeroed:
[39430.908615][ T1171] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000
[39430.911397][ T1171] pc : __pi_strcmp+0x20/0x140
[39430.911441][ T1171] lr : gadget_match_driver+0x34/0x60
...
[39430.911890][ T1171] usb_gadget_register_driver_owner+0x50/0xf8
[39430.911910][ T1171] gadget_dev_desc_UDC_store+0xf4/0x140
[39430.931308][ T1171] configfs_write_iter+0xec/0x134
[39430.957058][ T1171] Workqueue: events_freezable __dwc3_set_mode
[39430.957287][ T1171] dwc3_gadget_exit+0x34/0x8c
[39430.957304][ T1171] __dwc3_set_mode+0xc0/0x664
Fix this by ensuring the udc structure remains allocated until the
gadget is released. To achieve this, introduce a new
usb_gadget_release() routine to the core. When the gadget is added,
usb_add_gadget() stores the gadget's release routine in the udc
structure and takes a reference to the udc. When the gadget is
released, usb_gadget_release() drops the reference to the udc and
then calls the gadget's release routine. |
| In the Linux kernel, the following vulnerability has been resolved:
bpf: Allow LPM map access from sleepable BPF programs
trie_lookup_elem() annotates its rcu_dereference_check() walks with
only rcu_read_lock_bh_held(). Because rcu_dereference_check(p, c)
resolves to "c || rcu_read_lock_held()", this passes for XDP/NAPI and
classic RCU readers but fails for sleepable BPF programs, which enter
via __bpf_prog_enter_sleepable() and hold only rcu_read_lock_trace().
trie_update_elem() and trie_delete_elem() have the same problem in a
different form: they walk the trie with plain rcu_dereference(), which
asserts rcu_read_lock_held() unconditionally. Both are reachable from
sleepable BPF programs via the bpf_map_update_elem / bpf_map_delete_elem
helpers, and from the syscall path under classic rcu_read_lock(). In
the writer paths the trie is actually protected by trie->lock (an
rqspinlock taken across the walk); we never relied on the RCU read-side
lock to keep nodes alive there.
A sleepable LSM hook that ends up touching an LPM trie therefore
triggers lockdep on debug kernels:
=============================
WARNING: suspicious RCU usage
7.1.0-... Tainted: G E
-----------------------------
kernel/bpf/lpm_trie.c:249 suspicious rcu_dereference_check() usage!
1 lock held by net_tests/540:
#0: (rcu_tasks_trace_srcu_struct){....}-{0:0},
at: __bpf_prog_enter_sleepable+0x26/0x280
Call Trace:
dump_stack_lvl
lockdep_rcu_suspicious
trie_lookup_elem
bpf_prog_..._enforce_security_socket_connect
bpf_trampoline_...
security_socket_connect
__sys_connect
do_syscall_64
This is lockdep-only -- no UAF, since Tasks Trace RCU does serialize
against the trie's reclaim path -- but it spams the console once per
distinct callsite on every debug kernel running a sleepable BPF LSM
that touches an LPM trie, which is increasingly common.
For the lookup path, switch the rcu_dereference_check() annotation
from rcu_read_lock_bh_held() to bpf_rcu_lock_held(), which accepts all
three contexts (classic, BH, Tasks Trace). Other map types already
follow this convention.
For trie_update_elem() and trie_delete_elem(), annotate the walks as
rcu_dereference_protected(*p, 1) -- matching trie_free() in the same
file -- since trie->lock is held across the walk. rqspinlock has no
lockdep_map, so the predicate degenerates to '1' rather than
lockdep_is_held(&trie->lock); the protection is real but not
machine-verifiable. trie_get_next_key() also uses bare
rcu_dereference() but is reachable only from the BPF syscall, which
holds classic rcu_read_lock() before dispatching, so it is left
untouched. |
| In the Linux kernel, the following vulnerability has been resolved:
bpf: Validate BTF repeated field counts before expansion
btf_parse_struct_metas() walks user-supplied BTF during BPF_BTF_LOAD,
and btf_repeat_fields() expands repeatable fields from array elements
into the fixed BTF_FIELDS_MAX scratch array used by btf_parse_fields().
The remaining-capacity check performs the expanded field count calculation
in u32. A malformed BTF can wrap that calculation, causing the check to
pass even when the expanded field count exceeds the scratch array
capacity. The following memcpy() can then write past the end of the
array.
Use checked addition and multiplication before copying repeated fields
and reject impossible counts. |
| In the Linux kernel, the following vulnerability has been resolved:
xfs: fix exchmaps reservation limit check
xfs_exchmaps_estimate_overhead() adds the bmbt and rmapbt
overhead to a local resblks variable, but the final UINT_MAX
check still tests req->resblks. That is the reservation value
from before the overhead was added.
The computed value is stored back in req->resblks and later passed
to xfs_trans_alloc(), whose block reservation argument is unsigned
int. Check the computed reservation so the existing limit applies
to the value that will be used. |
| In the Linux kernel, the following vulnerability has been resolved:
HID: letsketch: fix UAF on inrange_timer at driver unbind
letsketch_driver does not provide a .remove callback, but
letsketch_probe() arms a per-device timer:
timer_setup(&data->inrange_timer, letsketch_inrange_timeout, 0);
The timer is re-armed from letsketch_raw_event() with a 100 ms
timeout on every pen-in-range report, and its callback dereferences
data->input_tablet to deliver a synthetic BTN_TOOL_PEN release.
letsketch_data is allocated with devm_kzalloc(), and its input_dev
fields are devm-allocated via letsketch_setup_input_tablet(). On
device unbind (USB unplug or rmmod), the HID core runs its default
teardown and devm cleanup frees both letsketch_data and the input
devices. Because no .remove callback exists, nothing drains the
timer first: if raw_event armed it within ~100 ms of the unbind,
the pending timer fires on freed memory. This is a UAF read of
data and of data->input_tablet, followed by input_report_key() /
input_sync() into the freed input_dev.
The same problem can occur on the probe error path: if
hid_hw_start() enabled I/O on an always-poll-quirk device and then
failed, raw_event may have armed the timer before devm releases
data.
Fix by adding a .remove callback that calls hid_hw_stop() first.
hid_hw_stop() synchronously kills the URBs that deliver raw_event(),
so once it returns no path can re-arm the timer. timer_shutdown_sync()
then drains any in-flight callback and permanently disables further
mod_timer() calls. Apply the same timer_shutdown_sync() in the probe
error path so the timer is guaranteed not to outlive data. |
| In the Linux kernel, the following vulnerability has been resolved:
HID: wacom: fix slab-out-of-bounds write in wacom_wac_queue_insert
wacom_wac_queue_insert() calls kfifo_skip() in a loop when the kfifo
doesn't have enough space for the incoming report. If the kfifo is
empty, kfifo_skip() reads stale data left in the kmalloc'd buffer
via __kfifo_peek_n() and interprets it as a record length, advancing
fifo->out by that garbage value. This corrupts the internal kfifo
state, causing kfifo_unused() to return a value much larger than the
actual buffer size, which bypasses __kfifo_in_r()'s guard:
if (len + recsize > kfifo_unused(fifo))
return 0;
kfifo_copy_in() then performs an out-of-bounds memcpy, writing up to
3842 bytes past the 256-byte buffer.
Add a !kfifo_is_empty() condition to the while loop so kfifo_skip()
is never called on an empty fifo, and check the return value of
kfifo_in() to reject reports that are too large for the fifo. |
| In the Linux kernel, the following vulnerability has been resolved:
s390: Revert support for DCACHE_WORD_ACCESS
load_unaligned_zeropad() reads eight bytes from unaligned addresses and may
cross page boundaries. It handles exceptions which may happen if reading
from the second page results in an exception.
For pages which are donated to the Ultravisor for secure execution purposes
the do_secure_storage_access() exception handler however does not handle
such exceptions correctly. Such an exception may result in an endless
exception loop which will never be resolved.
An attempt to fix this [1] turned out to be not sufficient. For now revert
load_unaligned_zeropad() until this problem has been resolved in a proper
way.
Note that the implementation of load_unaligned_zeropad() itself is
correct. The revert is just a temporary workaround until there is complete
fix for secure storage access exceptions.
[1] commit b00be77302d7 ("s390/mm: Add missing secure storage access fixups for donated memory") |
| In the Linux kernel, the following vulnerability has been resolved:
posix-cpu-timers: Fix pid refcount leak in do_cpu_nanosleep() error path
In do_cpu_nanosleep(), posix_cpu_timer_create() takes a pid reference
via get_pid() and stores it in timer.it.cpu.pid. If the subsequent
posix_cpu_timer_set() call fails, the function returns immediately
without calling posix_cpu_timer_del() to release the pid reference,
causing a leak.
Fix it by calling posix_cpu_timer_del() before the unlock-and-return
on the error path, consistent with the other exit paths in the same
function. |
| In the Linux kernel, the following vulnerability has been resolved:
firmware_loader: fix device reference leak in firmware_upload_register()
firmware_upload_register()
-> fw_create_instance()
-> device_initialize()
After fw_create_instance() succeeds, the lifetime of the embedded struct
device is expected to be managed through the device core reference
counting, since fw_create_instance() has already called
device_initialize().
In firmware_upload_register(), if alloc_lookup_fw_priv() fails after
fw_create_instance() succeeds, the code reaches free_fw_sysfs and frees
fw_sysfs directly instead of releasing the device reference with
put_device(). This may leave the reference count of the embedded struct
device unbalanced, resulting in a refcount leak.
The issue was identified by a static analysis tool I developed and
confirmed by manual review. Fix this by using put_device(fw_dev) in the
failure path and letting fw_dev_release() handle the final cleanup,
instead of freeing the instance directly from the error path. |
| In the Linux kernel, the following vulnerability has been resolved:
ksmbd: validate NTLMv2 response before updating session key
ksmbd_auth_ntlmv2() derives the NTLMv2 session key into
sess->sess_key before it verifies the NTLMv2 response.
ksmbd_decode_ntlmssp_auth_blob() then continues into KEY_XCH even
when ksmbd_auth_ntlmv2() failed.
With SMB3 multichannel binding, the failed authentication operates on
an existing session and the session setup error path does not expire
binding sessions. A client can send a binding session setup with a
bad NT proof and KEY_XCH and still modify sess->sess_key before
STATUS_LOGON_FAILURE is returned.
Relevant path:
smb2_sess_setup()
-> conn->binding = true
-> ntlm_authenticate()
-> session_user()
-> ksmbd_decode_ntlmssp_auth_blob()
-> ksmbd_auth_ntlmv2()
-> calc_ntlmv2_hash()
-> hmac_md5_usingrawkey(..., sess->sess_key)
-> crypto_memneq() returns mismatch
-> KEY_XCH arc4_crypt(..., sess->sess_key, ...)
-> out_err without expiring the binding session
Derive the base session key into a local buffer and copy it to
sess->sess_key only after the proof matches. Return immediately on
authentication failure so KEY_XCH is only processed after successful
authentication. |
| In the Linux kernel, the following vulnerability has been resolved:
ksmbd: use opener credentials for ADS I/O
Alternate data streams are stored as xattrs. Unlike regular file I/O,
their read and write paths therefore call VFS xattr helpers which recheck
inode permissions and LSM policy using the current task credentials.
Run ADS I/O with the credentials captured when the SMB handle was opened. |
| In the Linux kernel, the following vulnerability has been resolved:
ksmbd: use opener credentials for delete-on-close
Delete-on-close can be completed by deferred or durable handle teardown,
where no request work is available. Both the base-file unlink and the ADS
xattr removal consequently run with the ksmbd worker credentials and can
bypass filesystem permission checks.
Run both operations with the credentials captured in struct file when the
handle was opened. This preserves the authenticated user's fsuid, fsgid,
supplementary groups and capability restrictions at final close. |
| In the Linux kernel, the following vulnerability has been resolved:
net: af_key: initialize alg_key_len for IPComp states
pfkey_msg2xfrm_state() handles the IPComp (SADB_X_SATYPE_IPCOMP) case by
allocating x->calg and copying only the algorithm name:
x->calg = kmalloc_obj(*x->calg);
if (!x->calg) {
err = -ENOMEM;
goto out;
}
strcpy(x->calg->alg_name, a->name);
x->props.calgo = sa->sadb_sa_encrypt;
Unlike the authentication (x->aalg) and encryption (x->ealg) branches of
the same function, the compression branch never initializes
calg->alg_key_len. IPComp carries no key and the allocation only
reserves sizeof(struct xfrm_algo) (i.e. no room for a key), so the field
is left containing uninitialized slab data.
calg->alg_key_len is later used as a length by xfrm_algo_clone() when an
IPComp state is cloned during XFRM_MSG_MIGRATE:
xfrm_state_migrate()
xfrm_state_clone_and_setup()
x->calg = xfrm_algo_clone(orig->calg);
kmemdup(orig, xfrm_alg_len(orig));
where xfrm_alg_len() returns sizeof(*alg) + (alg_key_len + 7) / 8. With
a non-zero garbage alg_key_len, kmemdup() reads past the end of the
68-byte calg object. Adding an IPComp SA via PF_KEY and then migrating
it triggers (net-next, KASAN, init_on_alloc=0):
BUG: KASAN: slab-out-of-bounds in kmemdup_noprof+0x44/0x60
Read of size 4164 at addr ff11000025a74980 by task diag2/9287
CPU: 3 UID: 0 PID: 9287 Comm: diag2 7.1.0-rc6-g903db046d557 #1
Call Trace:
<TASK>
dump_stack_lvl+0x10e/0x1f0
print_report+0xf7/0x600
kasan_report+0xe4/0x120
kasan_check_range+0x105/0x1b0
__asan_memcpy+0x23/0x60
kmemdup_noprof+0x44/0x60
xfrm_state_migrate+0x70a/0x1da0
xfrm_migrate+0x753/0x18a0
xfrm_do_migrate+0xb47/0xf10
xfrm_user_rcv_msg+0x411/0xb50
netlink_rcv_skb+0x158/0x420
xfrm_netlink_rcv+0x71/0x90
netlink_unicast+0x584/0x850
netlink_sendmsg+0x8b0/0xdc0
____sys_sendmsg+0x9f7/0xb90
___sys_sendmsg+0x134/0x1d0
__sys_sendmsg+0x16d/0x220
do_syscall_64+0x116/0x7d0
entry_SYSCALL_64_after_hwframe+0x77/0x7f
</TASK>
Allocated by task 9287:
kasan_save_stack+0x33/0x60
kasan_save_track+0x14/0x30
__kasan_kmalloc+0xaa/0xb0
pfkey_add+0x2652/0x2ea0
pfkey_process+0x6d0/0x830
pfkey_sendmsg+0x42c/0x850
__sys_sendto+0x461/0x4b0
__x64_sys_sendto+0xe0/0x1c0
do_syscall_64+0x116/0x7d0
entry_SYSCALL_64_after_hwframe+0x77/0x7f
The buggy address belongs to the object at ff11000025a74980
which belongs to the cache kmalloc-96 of size 96
The buggy address is located 0 bytes inside of
allocated 68-byte region [ff11000025a74980, ff11000025a749c4)
Depending on the uninitialized value the same field can instead request
an oversized kmemdup() allocation and make the migration clone fail.
The XFRM netlink path is not affected: verify_one_alg() rejects an
XFRMA_ALG_COMP attribute shorter than xfrm_alg_len(), so a calg added via
XFRM_MSG_NEWSA is always self-consistent.
Initialize calg->alg_key_len to 0, matching the aalg/ealg branches. |
| In the Linux kernel, the following vulnerability has been resolved:
usb: dwc3: run gadget disconnect from sleepable suspend context
dwc3_gadget_suspend() takes dwc->lock with IRQs disabled and then calls
dwc3_disconnect_gadget(). For async callbacks that helper only uses
plain spin_unlock()/spin_lock(), so the gadget ->disconnect() callback
still runs with IRQs disabled and any sleepable callback trips Lockdep.
This issue was found by our static analysis tool and then manually
reviewed against the current tree.
The grounded PoC kept the dwc3_gadget_suspend() ->
dwc3_disconnect_gadget() -> gadget_driver->disconnect() chain, and
Lockdep reported:
BUG: sleeping function called from invalid context
gadget_disconnect+0x21/0x39 [vuln_msv]
dwc3_gadget_suspend.constprop.0+0x2b/0x42 [vuln_msv]
Keep the disconnect callback selection in one common helper, but add a
sleepable suspend-side wrapper which snapshots the callback under
dwc->lock and then runs it after spin_unlock_irqrestore(). The regular
event path still uses the existing spin_unlock()/spin_lock() window. |
| In the Linux kernel, the following vulnerability has been resolved:
hwrng: virtio: clamp device-reported used.len at copy_data()
random_recv_done() stores the device-reported used.len directly into
vi->data_avail. copy_data() then indexes vi->data[] using
vi->data_idx (advanced by previous copy_data() calls) and issues a
memcpy() without re-validating either value against the posted
buffer size sizeof(vi->data) (SMP_CACHE_BYTES bytes, typically 32
or 64).
A malicious or buggy virtio-rng backend can set used.len beyond
sizeof(vi->data), steering the memcpy() past the end of the inline
array into adjacent kmalloc-1k slab bytes. hwrng_fillfn() mixes
those bytes into the guest RNG, and guest root can also observe
them directly via /dev/hwrng.
Concrete impact is inside the guest:
- Memory-safety / hardening: any virtio-rng backend that
over-reports used.len causes the driver to read past vi->data
into unrelated slab contents. hwrng_fillfn() is a kernel thread
that runs as soon as the device is probed; no guest userspace
interaction is required to first-trigger the OOB.
- Cross-boundary leak (confidential-compute threat model): a
malicious hypervisor cooperating with a malicious or compromised
guest root userspace can use /dev/hwrng as a leak channel for
guest-kernel heap data. The host sets a large used.len, guest
root reads /dev/hwrng, and the returned bytes contain guest
kernel slab contents that were adjacent to vi->data. In
practice, confidential-compute guests (SEV-SNP, TDX) usually
disable virtio-rng entirely, so this path is narrow, but the
fix is still worth carrying because the underlying
memory-safety bug contaminates the guest RNG on any host.
KASAN confirms the OOB on a 7.1-rc4 guest whose virtio-rng backend
has been patched to report used.len = 0x10000:
BUG: KASAN: slab-out-of-bounds in virtio_read+0x394/0x5d0
Read of size 64 at addr ffff88800ae0ba20 by task hwrng/52
Call Trace:
__asan_memcpy+0x23/0x60
virtio_read+0x394/0x5d0
hwrng_fillfn+0xb2/0x470
kthread+0x2cc/0x3a0
Allocated by task 1:
probe_common+0xa5/0x660
virtio_dev_probe+0x549/0xbc0
The buggy address belongs to the object at ffff88800ae0b800
which belongs to the cache kmalloc-1k of size 1024
The buggy address is located 0 bytes to the right of
allocated 544-byte region [ffff88800ae0b800, ffff88800ae0ba20)
Same class of bug as commit c04db81cd028 ("net/9p: Fix buffer
overflow in USB transport layer"), which hardened
usb9pfs_rx_complete() against unchecked device-reported length in
the USB 9p transport.
With the clamp at point of use and array_index_nospec() in place,
the same harness boots cleanly: copy_data() returns zero for the
bogus report, the device-supplied bytes after data_idx are
discarded, and the driver issues a fresh request. |
| In the Linux kernel, the following vulnerability has been resolved:
mm/damon/ops-common: handle extreme intervals in damon_hot_score()
Fix three issues in damon_hot_score() that comes from wrong handling of
extreme (zero or too high) monitoring intervals user setup.
When the user sets sampling interval zero, damon_max_nr_accesses(), which
is called from damon_hot_score(), causes a divide-by-zero. Needless to
say, it is a problem.
When the user sets the aggregation interval zero, the function returns
zero. It is wrong, since the real maximum nr_acceses in the setup should
be one. Worse yet, it can cause another divide-by-zero from its caller,
damon_hot_score(), since it uses damon_max_nr_accesses() return value as a
denominator.
When the user sets the aggregation interval very high, damon_hot_score()
could return a value out of [0, DAMOS_MAX_SCORE] range. Since the return
value is used as an index to the regions_score_histogram array, which is
DAMOS_MAX_SCORE+1 size, it causes out of bounds array access.
The issues can be relatively easily reproduced like below. The sysfs
write permission is required, though.
# ./damo start --damos_action lru_prio --damos_quota_space 100M \
--damos_quota_interval 1s
# cd /sys/kernel/mm/damon/admin/kdamonds/0
# echo 0 > contexts/0/monitoring_attrs/intervals/sample_us
# echo 0 > contexts/0/monitoring_attrs/intervals/aggr_us
# echo commit > state
# dmesg
[...]
[ 131.329762] Oops: divide error: 0000 [#1] SMP NOPTI
[...]
[ 131.336089] RIP: 0010:damon_hot_score+0x27/0xd0
[...]
Fix the divide-by-zero intervals problems by explicitly handling the zero
intervals in damon_max_nr_accesses(). Fix the out-of-bound array access
by applying [0, DAMOS_MAX_SCORE] bounds before returning from
damon_hot_score().
The issue was discovered [1] by Sashiko. |
| In the Linux kernel, the following vulnerability has been resolved:
tcp: restore RCU grace period in tcp_ao_destroy_sock
Commit 51e547e8c89c ("tcp: Free TCP-AO/TCP-MD5 info/keys without RCU")
removed the call_rcu() callback from tcp_ao_destroy_sock(), arguing that
"the destruction of info/keys is delayed until the socket destructor"
and therefore "no one can discover it anymore".
That argument does not hold for the call site in tcp_connect()
(net/ipv4/tcp_output.c:4327-4332). At that point the socket is in
TCP_SYN_SENT, has already been inserted into the inet ehash by
inet_hash_connect() in tcp_v4_connect(), and is therefore very much
discoverable: any softirq running tcp_v4_rcv() on another CPU can take
the socket out of the ehash, walk into tcp_inbound_hash(), and load
tp->ao_info via implicit RCU before bh_lock_sock_nested() is taken on
the destroying CPU.
The reader path then enters __tcp_ao_do_lookup() (net/ipv4/tcp_ao.c:208)
which re-loads tp->ao_info via rcu_dereference_check(); the re-load can
still observe the (about-to-be-freed) pointer because there is no
synchronize_rcu() between rcu_assign_pointer(tp->ao_info, NULL) and
tcp_ao_info_free() in tcp_ao_destroy_sock(). The captured pointer is
then walked at line 223:
hlist_for_each_entry_rcu(key, &ao->head, node, ...)
The writer's synchronous kfree() is free to complete between the line
218 re-fetch and the line 223 hlist iteration. The slab is reused
(or simply LIST_POISON1-stamped if not yet reused) and the iteration
walks attacker-controlled or poison memory in softirq context.
Reproducer (no debug shim, stock x86_64 v7.1-rc2 SMP+KASAN, QEMU+KVM):
an unprivileged uid=1000 process inside CLONE_NEWUSER|CLONE_NEWNET
installs TCP_MD5SIG + TCP_AO_ADD_KEY on a TCP socket, sprays forged
TCP-AO segments toward its eventual 4-tuple via raw sockets, then
calls connect(). The md5-wins reconciliation in tcp_connect() fires
tcp_ao_destroy_sock(); the softirq backlog reader on the loopback
NAPI path crashes on the freed ao->head.first walk:
Oops: general protection fault, probably for non-canonical
address 0xfbd59c000000002f
KASAN: maybe wild-memory-access in range
[0xdead000000000178-0xdead00000000017f]
CPU: 0 UID: 1000 PID: 100 Comm: repro_userns
RIP: 0010:__tcp_ao_do_lookup+0x107/0x1c0
Call Trace: <IRQ>
__tcp_ao_do_lookup+0x107/0x1c0
tcp_ao_inbound_lookup.constprop.0+0x12a/0x200
tcp_inbound_ao_hash+0x5ea/0x1520
tcp_inbound_hash+0x7ce/0x1240
tcp_v4_rcv+0x1e7a/0x3e10
...
Restore the RCU grace period: re-add struct rcu_head to tcp_ao_info
and replace the synchronous tcp_ao_info_free() with a call_rcu()
callback. Readers that captured tp->ao_info before rcu_assign_pointer
NULLed it now see the object remain valid until rcu_read_unlock().
With the patch applied the reproducer runs cleanly for 2000 iterations
on the same kernel build. |
