| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| 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. |
| In the Linux kernel, the following vulnerability has been resolved:
drm/i915/gem: Fix phys BO pread/pwrite with offset
sg_page() returns struct page pointer not (void *) so the scaling
of pread/pwrite is wrong for phys BO and wrong parts of BO would be
accessed if non-zero offset is used.
Last impacted platform with overlay or cursor planes using phys
mapping was Gen3/945G/Lakeport.
(cherry picked from commit 3e49a2f85070b2fb672c1e0fdba281a4ea3aebe6) |
| In the Linux kernel, the following vulnerability has been resolved:
drm/xe/eustall: Fix drm_dev_put called before stream disable in close
In xe_eu_stall_stream_close(), drm_dev_put() is called before the
stream is disabled and its resources are freed. If this drops the
last reference, the device structures could be freed while the
subsequent cleanup code still accesses them, leading to a
use-after-free.
Fix this by moving drm_dev_put() after all device accesses are
complete. This matches the ordering in xe_oa_release().
(cherry picked from commit 35aff528f7297e949e5e19c9cd7fd748cf1cf21c) |
| In the Linux kernel, the following vulnerability has been resolved:
ipv6: mcast: Fix use-after-free when processing MLD queries
When processing an MLD query, a pointer to the multicast group address
is retrieved when initially parsing the packet. This pointer is later
dereferenced without being reloaded despite the fact that the skb header
might have been reallocated following the pskb_may_pull() calls, leading
to a use-after-free [1].
Fix by copying the multicast group address when the packet is initially
parsed.
[1]
BUG: KASAN: slab-use-after-free in __mld_query_work (net/ipv6/mcast.c:1512)
Read of size 8 at addr ffff8881154b8e90 by task kworker/4:1/118
Workqueue: mld mld_query_work
Call Trace:
<TASK>
dump_stack_lvl (lib/dump_stack.c:94 lib/dump_stack.c:120)
print_address_description.constprop.0 (mm/kasan/report.c:378)
print_report (mm/kasan/report.c:482)
kasan_report (mm/kasan/report.c:595)
__mld_query_work (net/ipv6/mcast.c:1512)
mld_query_work (net/ipv6/mcast.c:1563)
process_one_work (kernel/workqueue.c:3314)
worker_thread (kernel/workqueue.c:3397 kernel/workqueue.c:3478)
kthread (kernel/kthread.c:436)
ret_from_fork (arch/x86/kernel/process.c:158)
ret_from_fork_asm (arch/x86/entry/entry_64.S:245)
</TASK>
[...]
Freed by task 118:
kasan_save_stack (mm/kasan/common.c:57)
kasan_save_track (mm/kasan/common.c:78)
kasan_save_free_info (mm/kasan/generic.c:584)
__kasan_slab_free (mm/kasan/common.c:253 mm/kasan/common.c:285)
kfree (./include/linux/kasan.h:235 mm/slub.c:2689 mm/slub.c:6251 mm/slub.c:6566)
pskb_expand_head (net/core/skbuff.c:2335)
__pskb_pull_tail (net/core/skbuff.c:2878 (discriminator 4))
__mld_query_work (net/ipv6/mcast.c:1495 (discriminator 1))
mld_query_work (net/ipv6/mcast.c:1563)
process_one_work (kernel/workqueue.c:3314)
worker_thread (kernel/workqueue.c:3397 kernel/workqueue.c:3478)
kthread (kernel/kthread.c:436)
ret_from_fork (arch/x86/kernel/process.c:158)
ret_from_fork_asm (arch/x86/entry/entry_64.S:245) |
| In the Linux kernel, the following vulnerability has been resolved:
tee: optee: prevent use-after-free when the client exits before the supplicant
Commit 70b0d6b0a199 ("tee: optee: Fix supplicant wait loop") made the
client wait as killable so it can be interrupted during shutdown or
after a supplicant crash. This changes the original lifetime expectations:
the client task can now terminate while the supplicant is still processing
its request.
If the client exits first it removes the request from its queue and
kfree()s it, while the request ID remains in supp->idr. A subsequent
lookup on the supplicant path then dereferences freed memory, leading to
a use-after-free.
Serialise access to the request with supp->mutex:
* Hold supp->mutex in optee_supp_recv() and optee_supp_send() while
looking up and touching the request.
* Let optee_supp_thrd_req() notice that the client has terminated and
signal optee_supp_send() accordingly.
With these changes the request cannot be freed while the supplicant still
has a reference, eliminating the race. |
| In the Linux kernel, the following vulnerability has been resolved:
ipvs: clear the svc scheduler ptr early on edit
ip_vs_edit_service() while unbinding the old scheduler clears
the svc->scheduler ptr after the scheduler module initiates
RCU callbacks. This can cause packets to use the old
scheduler at the time when svc->sched_data is already freed
after RCU grace period.
Fix it by clearing the ptr early in ip_vs_unbind_scheduler(),
before the done_service method schedules any RCU callbacks.
Also, if the new scheduler fails to initialize when replacing
the old scheduler, try to restore the old scheduler while still
returning the error code. |
| In the Linux kernel, the following vulnerability has been resolved:
ALSA: PCM: Fix wait queue list corruption in snd_pcm_drain() on linked streams
snd_pcm_drain() uses init_waitqueue_entry which does not clear
entry.prev/next, and add_wait_queue with a conditional
remove_wait_queue that is skipped when to_check is no longer
in the group after concurrent UNLINK. The orphaned wait entry
remains on the unlinked substream sleep queue. On the next
drain iteration, add_wait_queue adds the entry to a new queue
while still linked on the old one, corrupting both lists. A
subsequent wake_up dereferences NULL at the func pointer
(mapped from the spinlock at offset 0 of the misinterpreted
wait_queue_head_t), causing a kernel panic.
Replace init_waitqueue_entry/add_wait_queue/conditional
remove_wait_queue with init_wait_entry/prepare_to_wait/
finish_wait. init_wait_entry clears prev/next via
INIT_LIST_HEAD on each iteration and sets
autoremove_wake_function which auto-removes the entry on
wake-up. finish_wait safely handles both the already-removed
and still-queued cases. |
| In the Linux kernel, the following vulnerability has been resolved:
net: mvpp2: sync RX data at the hardware packet offset
mvpp2 programs the RX queue packet offset, so hardware writes received
data at dma_addr + MVPP2_SKB_HEADROOM. The current CPU sync starts at
dma_addr and only covers rx_bytes + MVPP2_MH_SIZE bytes, which syncs the
unused headroom and misses the same number of bytes at the packet tail.
On non-coherent DMA systems this can leave the CPU reading stale cache
contents for the end of the received frame.
Use dma_sync_single_range_for_cpu() with MVPP2_SKB_HEADROOM as the range
offset so the sync covers the Marvell header and packet data actually
written by hardware. |
| In the Linux kernel, the following vulnerability has been resolved:
ALSA: timer: Forcibly close timer instances at closing
When snd_timer object is freed via snd_timer_free() and still pending
snd_timer_instance objects are assigned to the timer object, it tries
to unlink all instances and just set NULL to each ti->timer, then
releases the resources immediately. The problem is, however, when
there are slave timer instances that are associated with a master
instance linked to this timer: namely, those slave instances still
point to the freed timer object although the master instance is
unlinked, which may lead to user-after-free. The bug can be easily
triggered particularly when a new userspace-driven timers
(CONFIG_SND_UTIMER) is involved, since it can create and delete the
timer object via a simple file open/close, while the other
applications may keep accessing to that timer.
This patch is an attempt to paper over the problem above: now instead
of just unlinking, call snd_timer_close[_locked]() forcibly for each
pending timer instance, so that all assigned slave timer instances are
properly detached, too. Since snd_timer_close() might be called later
by the driver that created that instance, the check of
SNDRV_TIMER_IFLG_DEAD is added at the beginning, too. |
| In the Linux kernel, the following vulnerability has been resolved:
bpf: Use RCU-safe iteration in dev_map_redirect_multi() SKB path
The DEVMAP_HASH branch in dev_map_redirect_multi() uses
hlist_for_each_entry_safe() to iterate hash buckets, but this function
runs under RCU protection (called from xdp_do_generic_redirect_map()
in softirq context). Concurrent writers (__dev_map_hash_update_elem,
dev_map_hash_delete_elem) modify the list using RCU primitives
(hlist_add_head_rcu, hlist_del_rcu).
hlist_for_each_entry_safe() performs plain pointer dereferences without
rcu_dereference(), missing the acquire barrier needed to pair with
writers' rcu_assign_pointer(). On weakly-ordered architectures (ARM64,
POWER), a reader can observe a partially-constructed node. It also
defeats CONFIG_PROVE_RCU lockdep validation and KCSAN data-race
detection.
Replace with hlist_for_each_entry_rcu() using rcu_read_lock_bh_held()
as the lockdep condition, consistent with the rcu_dereference_check()
used in the DEVMAP (non-hash) branch of the same functions. Also fix
the same incorrect lockdep_is_held(&dtab->index_lock) condition in
dev_map_enqueue_multi(), where the lock is not held either. |
| In the Linux kernel, the following vulnerability has been resolved:
bpf: Fix stale offload->prog pointer after constant blinding
When a dev-bound-only BPF program (BPF_F_XDP_DEV_BOUND_ONLY) undergoes
JIT compilation with constant blinding enabled (bpf_jit_harden >= 2),
bpf_jit_blind_constants() clones the program. The original prog is then
freed in bpf_jit_prog_release_other(), which updates aux->prog to point
to the surviving clone, but fails to update offload->prog.
This leaves offload->prog pointing to the freed original program. When
the network namespace is subsequently destroyed, cleanup_net() triggers
bpf_dev_bound_netdev_unregister(), which iterates ondev->progs and calls
__bpf_prog_offload_destroy(offload->prog). Accessing the freed prog
causes a page fault:
BUG: unable to handle page fault for address: ffffc900085f1038
Workqueue: netns cleanup_net
RIP: 0010:__bpf_prog_offload_destroy+0xc/0x80
Call Trace:
__bpf_offload_dev_netdev_unregister+0x257/0x350
bpf_dev_bound_netdev_unregister+0x4a/0x90
unregister_netdevice_many_notify+0x2a2/0x660
...
cleanup_net+0x21a/0x320
The test sequence that triggers this reliably is:
1. Set net.core.bpf_jit_harden=2 (echo 2 > /proc/sys/net/core/bpf_jit_harden)
2. Run xdp_metadata selftest, which creates a dev-bound-only XDP
program on a veth inside a netns (./test_progs -t xdp_metadata)
3. cleanup_net -> page fault in __bpf_prog_offload_destroy
Dev-bound-only programs are unique in that they have an offload structure
but go through the normal JIT path instead of bpf_prog_offload_compile().
This means they are subject to constant blinding's prog clone-and-replace,
while also having offload->prog that must stay in sync.
Fix this by updating offload->prog in bpf_jit_prog_release_other(),
alongside the existing aux->prog update. Both are back-pointers to
the prog that must be kept in sync when the prog is replaced. |
| In the Linux kernel, the following vulnerability has been resolved:
bpf, sockmap: Take state lock for af_unix iter
When a BPF iterator program updates a sockmap, there is a race condition in
unix_stream_bpf_update_proto() where the `peer` pointer can become stale[1]
during a state transition TCP_ESTABLISHED -> TCP_CLOSE.
CPU0 bpf CPU1 close
-------- ----------
// unix_stream_bpf_update_proto()
sk_pair = unix_peer(sk)
if (unlikely(!sk_pair))
return -EINVAL;
// unix_release_sock()
skpair = unix_peer(sk);
unix_peer(sk) = NULL;
sock_put(skpair)
sock_hold(sk_pair) // UaF
More practically, this fix guarantees that the iterator program is
consistently provided with a unix socket that remains stable during
iterator execution.
[1]:
BUG: KASAN: slab-use-after-free in unix_stream_bpf_update_proto+0x155/0x490
Write of size 4 at addr ffff8881178c9a00 by task test_progs/2231
Call Trace:
dump_stack_lvl+0x5d/0x80
print_report+0x170/0x4f3
kasan_report+0xe4/0x1c0
kasan_check_range+0x125/0x200
unix_stream_bpf_update_proto+0x155/0x490
sock_map_link+0x71c/0xec0
sock_map_update_common+0xbc/0x600
sock_map_update_elem+0x19a/0x1f0
bpf_prog_bbbf56096cdd4f01_selective_dump_unix+0x20c/0x217
bpf_iter_run_prog+0x21e/0xae0
bpf_iter_unix_seq_show+0x1e0/0x2a0
bpf_seq_read+0x42c/0x10d0
vfs_read+0x171/0xb20
ksys_read+0xff/0x200
do_syscall_64+0xf7/0x5e0
entry_SYSCALL_64_after_hwframe+0x76/0x7e
Allocated by task 2236:
kasan_save_stack+0x30/0x50
kasan_save_track+0x14/0x30
__kasan_slab_alloc+0x63/0x80
kmem_cache_alloc_noprof+0x1d5/0x680
sk_prot_alloc+0x59/0x210
sk_alloc+0x34/0x470
unix_create1+0x86/0x8a0
unix_stream_connect+0x318/0x15b0
__sys_connect+0xfd/0x130
__x64_sys_connect+0x72/0xd0
do_syscall_64+0xf7/0x5e0
entry_SYSCALL_64_after_hwframe+0x76/0x7e
Freed by task 2236:
kasan_save_stack+0x30/0x50
kasan_save_track+0x14/0x30
kasan_save_free_info+0x3b/0x70
__kasan_slab_free+0x47/0x70
kmem_cache_free+0x11c/0x590
__sk_destruct+0x432/0x6e0
unix_release_sock+0x9b3/0xf60
unix_release+0x8a/0xf0
__sock_release+0xb0/0x270
sock_close+0x18/0x20
__fput+0x36e/0xac0
fput_close_sync+0xe5/0x1a0
__x64_sys_close+0x7d/0xd0
do_syscall_64+0xf7/0x5e0
entry_SYSCALL_64_after_hwframe+0x76/0x7e |
| In the Linux kernel, the following vulnerability has been resolved:
net/sched: taprio: fix use-after-free in advance_sched() on schedule switch
In advance_sched(), when should_change_schedules() returns true,
switch_schedules() is called to promote the admin schedule to oper.
switch_schedules() queues the old oper schedule for RCU freeing via
call_rcu(), but 'next' still points into an entry of the old oper
schedule. The subsequent 'next->end_time = end_time' and
rcu_assign_pointer(q->current_entry, next) are use-after-free.
Fix this by selecting 'next' from the new oper schedule immediately
after switch_schedules(), and using its pre-calculated end_time.
setup_first_end_time() sets the first entry's end_time to
base_time + interval when the schedule is installed, so the value
is already correct.
The deleted 'end_time = sched_base_time(admin)' assignment was also
harmful independently: it would overwrite the new first entry's
pre-calculated end_time with just base_time. |
| In the Linux kernel, the following vulnerability has been resolved:
netfilter: nf_tables: join hook list via splice_list_rcu() in commit phase
Publish new hooks in the list into the basechain/flowtable using
splice_list_rcu() to ensure netlink dump list traversal via rcu is safe
while concurrent ruleset update is going on. |
| In the Linux kernel, the following vulnerability has been resolved:
bonding: 3ad: implement proper RCU rules for port->aggregator
syzbot found a data-race in bond_3ad_get_active_agg_info /
bond_3ad_state_machine_handler [1] which hints at lack of proper
RCU implementation.
Add __rcu qualifier to port->aggregator, and add proper RCU API.
[1]
BUG: KCSAN: data-race in bond_3ad_get_active_agg_info / bond_3ad_state_machine_handler
write to 0xffff88813cf5c4b0 of 8 bytes by task 36 on cpu 0:
ad_port_selection_logic drivers/net/bonding/bond_3ad.c:1659 [inline]
bond_3ad_state_machine_handler+0x9d5/0x2d60 drivers/net/bonding/bond_3ad.c:2569
process_one_work kernel/workqueue.c:3302 [inline]
process_scheduled_works+0x4f0/0x9c0 kernel/workqueue.c:3385
worker_thread+0x58a/0x780 kernel/workqueue.c:3466
kthread+0x22a/0x280 kernel/kthread.c:436
ret_from_fork+0x146/0x330 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
read to 0xffff88813cf5c4b0 of 8 bytes by task 22063 on cpu 1:
__bond_3ad_get_active_agg_info drivers/net/bonding/bond_3ad.c:2858 [inline]
bond_3ad_get_active_agg_info+0x8c/0x230 drivers/net/bonding/bond_3ad.c:2881
bond_fill_info+0xe0f/0x10f0 drivers/net/bonding/bond_netlink.c:853
rtnl_link_info_fill net/core/rtnetlink.c:906 [inline]
rtnl_link_fill+0x1d7/0x4e0 net/core/rtnetlink.c:927
rtnl_fill_ifinfo+0xf8e/0x1380 net/core/rtnetlink.c:2168
rtmsg_ifinfo_build_skb+0x11c/0x1b0 net/core/rtnetlink.c:4453
rtmsg_ifinfo_event net/core/rtnetlink.c:4486 [inline]
rtmsg_ifinfo+0x6d/0x110 net/core/rtnetlink.c:4495
__dev_notify_flags+0x76/0x390 net/core/dev.c:9790
netif_change_flags+0xac/0xd0 net/core/dev.c:9823
do_setlink+0x905/0x2950 net/core/rtnetlink.c:3180
rtnl_group_changelink net/core/rtnetlink.c:3813 [inline]
__rtnl_newlink net/core/rtnetlink.c:3981 [inline]
rtnl_newlink+0xf55/0x1400 net/core/rtnetlink.c:4109
rtnetlink_rcv_msg+0x64b/0x720 net/core/rtnetlink.c:6995
netlink_rcv_skb+0x123/0x220 net/netlink/af_netlink.c:2550
rtnetlink_rcv+0x1c/0x30 net/core/rtnetlink.c:7022
netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
netlink_unicast+0x5a8/0x680 net/netlink/af_netlink.c:1344
netlink_sendmsg+0x5c8/0x6f0 net/netlink/af_netlink.c:1894
sock_sendmsg_nosec net/socket.c:787 [inline]
__sock_sendmsg net/socket.c:802 [inline]
____sys_sendmsg+0x563/0x5b0 net/socket.c:2698
___sys_sendmsg+0x195/0x1e0 net/socket.c:2752
__sys_sendmsg net/socket.c:2784 [inline]
__do_sys_sendmsg net/socket.c:2789 [inline]
__se_sys_sendmsg net/socket.c:2787 [inline]
__x64_sys_sendmsg+0xd4/0x160 net/socket.c:2787
x64_sys_call+0x194c/0x3020 arch/x86/include/generated/asm/syscalls_64.h:47
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x12c/0x3b0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
value changed: 0x0000000000000000 -> 0xffff88813cf5c400
Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 22063 Comm: syz.0.31122 Tainted: G W syzkaller #0 PREEMPT(full)
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 |
| In the Linux kernel, the following vulnerability has been resolved:
net: ena: PHC: Fix potential use-after-free in get_timestamp
Move the phc->active check and resp pointer assignment to after
acquiring the spinlock. Previously, phc->active was checked without
holding the lock, and resp was cached from ena_dev->phc.virt_addr
before the lock was acquired.
If ena_com_phc_destroy() runs between the lockless active check and
the lock acquisition, it sets active=false, releases the lock, frees
the DMA memory, and sets virt_addr=NULL. The get_timestamp path would
then read a NULL virt_addr and dereference it.
With both the active check and the pointer read under the lock,
destroy cannot free the memory while get_timestamp is using it. |
| In the Linux kernel, the following vulnerability has been resolved:
sctp: stream: fully roll back denied add-stream state
When ADD_OUT_STREAMS is denied, SCTP only shrinks the queued chunks and
then lowers outcnt. That leaves removed stream metadata behind, so a
later re-add can reuse a stale ext and hit a null-pointer dereference in
the scheduler get path.
Fix the rollback by tearing down the removed stream state the same way
other stream resizes do. Unschedule the current scheduler state, drop
the removed stream ext state with sctp_stream_outq_migrate(), and then
reschedule the remaining streams.
This keeps scheduler-private RR/FC/PRIO lists consistent while fully
rolling back denied outgoing stream additions. |
| In the Linux kernel, the following vulnerability has been resolved:
sctp: purge outqueue on stale COOKIE-ECHO handling
sctp_stream_update() is only invoked when the association is moved into
COOKIE_WAIT during association setup/reconfiguration. In this path, the
outbound stream scheduler state (stream->out_curr) is expected to be
clean, since no user data should have been transmitted yet unless the
state machine has already partially progressed.
However, a corner case exists in sctp_sf_do_5_2_6_stale(): when a
Stale Cookie ERROR is received, the association is rolled back from
COOKIE_ECHOED to COOKIE_WAIT. In this scenario, user data may already
have been queued and even bundled with the COOKIE-ECHO chunk.
During the rollback, sctp_stream_update() frees the old stream table
and installs a new one, but it does not invalidate stream->out_curr.
As a result, out_curr may still point to a freed sctp_stream_out
entry from the previous stream state.
Later, SCTP scheduler dequeue paths (FCFS, RR, PRIO, etc.) rely on
stream->out_curr->ext, which can lead to use-after-free once the old
stream state has been released via sctp_stream_free().
This results in crashes such as (reported by Yuqi):
BUG: KASAN: slab-use-after-free in sctp_sched_fcfs_dequeue+0x13a/0x140
Read of size 8 at addr ff1100004d4d3208 by task mini_poc/9312
CPU: 1 UID: 1001 PID: 9312 Comm: mini_poc Not tainted
7.1.0-rc1-00305-gbd3a4795d574 #5 PREEMPT(full)
sctp_sched_fcfs_dequeue+0x13a/0x140
sctp_outq_flush+0x1603/0x33e0
sctp_do_sm+0x31c9/0x5d30
sctp_assoc_bh_rcv+0x392/0x6f0
sctp_inq_push+0x1db/0x270
sctp_rcv+0x138d/0x3c10
Fix this by fully purging the association outqueue when handling the
Stale Cookie case. This ensures all pending transmit and retransmit
state is dropped, and any scheduler cached pointers are invalidated,
making it safe to rebuild stream state during COOKIE_WAIT restart.
Updating only stream->out_curr would be insufficient, since queued
and retransmittable data would still reference the old stream state and
trigger later use-after-free in dequeue paths. |
| In the Linux kernel, the following vulnerability has been resolved:
ipc: limit next_id allocation to the valid ID range
The checkpoint/restore sysctl path can request the next SysV IPC id
through ids->next_id. ipc_idr_alloc() currently forwards that request to
idr_alloc() with an open-ended upper bound.
If the valid tail of the SysV IPC id space is full, the allocation can
spill beyond ipc_mni. The returned SysV IPC id still uses the normal
index encoding, so later lookup and removal can target the wrong slot.
This leaves the real IDR entry behind and breaks the IDR state for the
object.
The bug is in ipc_idr_alloc() in the checkpoint/restore path.
1. ids->next_id is passed to:
idr_alloc(&ids->ipcs_idr, new, ipcid_to_idx(next_id), 0, ...)
2. The zero upper bound makes the allocation effectively open-ended.
Once the valid SysV IPC tail is occupied, idr_alloc() can spill past
ipc_mni and allocate an entry beyond the valid IPC id range.
3. The new object id is still encoded with the narrower SysV IPC index
width:
new->id = (new->seq << ipcmni_seq_shift()) + idx
4. Later removal goes through ipc_rmid(), which uses:
ipcid_to_idx(ipcp->id)
That truncates the real IDR index. An object actually stored at a
high index can then be removed as if it lived at a low in-range
index.
5. For shared memory, shm_destroy() frees the current object anyway, but
the real high IDR slot is left behind as a dangling pointer.
6. A subsequent walk of /proc/sysvipc/shm reaches the stale IDR entry
and dereferences freed memory.
Prevent this by bounding the requested allocation to ipc_mni so the
checkpoint/restore path fails once the valid range is exhausted. |
