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.
In the Linux kernel, the following vulnerability has been resolved:
batman-adv: fix fragment reassembly length accounting
batman-adv keeps a running payload length for queued fragments and uses it
to validate a fragment chain before reassembly.
That accounting currently allows the accumulated fragment length to be
truncated during updates. As a result, malformed fragment chains can
bypass the intended validation and drive reassembly with inconsistent
length state, leading to a local denial of service.
Fix the accounting by storing the accumulated length in a length-typed
field and rejecting update overflows before the existing validation logic
runs.
The fix was verified against the original reproducer and against valid
fragment reassembly paths.
In the Linux kernel, the following vulnerability has been resolved:
netfilter: ip6t_hbh: reject oversized option lists
struct ip6t_opts stores at most IP6T_OPTS_OPTSNR option descriptors,
but hbh_mt6_check() does not reject larger optsnr values supplied from
userspace.
Validate optsnr in the rule setup path so only match data that fits the
fixed-size opts array can be installed. This follows the existing xtables
pattern of rejecting invalid user-provided counts in checkentry() and
keeps the packet matching path unchanged.
`struct ip6t_opts` has a fixed `opts[IP6T_OPTS_OPTSNR]` array,
where `IP6T_OPTS_OPTSNR` is 16, then off-by-one array access is possible:
[ 137.924693][ T8692] UBSAN: array-index-out-of-bounds in ../net/ipv6/netfilter/ip6t_hbh.c:110:29
[ 137.926167][ T8692] index 16 is out of range for type '__u16 [16]'
In the Linux kernel, the following vulnerability has been resolved:
batman-adv: frag: disallow unicast fragment in fragment
batadv_frag_skb_buffer() is called by batadv_batman_skb_recv() when a
BATADV_UNICAST_FRAG packet is received. Once all fragments are collected
and the packet is reassembled, batadv_recv_frag_packet() calls
batadv_batman_skb_recv() again to process the defragmented payload.
A malicious sender can craft a BATADV_UNICAST_FRAG packet whose reassembled
payload is itself a BATADV_UNICAST_FRAG packet (matryoshka-style nesting).
Each nesting level recurses through batadv_batman_skb_recv() without bound,
growing the kernel stack until it is exhausted.
Since refragmentation or fragments in fragments are not actually allowed,
discard all packets which are still BATADV_UNICAST_FRAG packets after the
defragmentation process.
In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: serialize accept_q access
bt_sock_poll() walks the accept queue without synchronization, while
child teardown can unlink the same socket and drop its last reference.
The unsynchronized accept queue walk has existed since the initial
Bluetooth import.
Protect accept_q with a dedicated lock for queue updates and polling.
Also rework bt_accept_dequeue() to take temporary child references under
the queue lock before dropping it and locking the child socket.
In the Linux kernel, the following vulnerability has been resolved:
netfilter: xt_policy: fix strict mode inbound policy matching
match_policy_in() walks sec_path entries from the last transform to the
first one, but strict policy matching needs to consume info->pol[] in
the same forward order as the rule layout.
Derive the strict-match policy position from the number of transforms
already consumed so that multi-element inbound rules are matched
consistently.
In the Linux kernel, the following vulnerability has been resolved:
ip6_vti: set netns_immutable on the fallback device.
john1988 and Noam Rathaus reported that vti6_init_net() does not set the
netns_immutable flag on the per-netns fallback tunnel device (ip6_vti0).
Other similar tunnel drivers (like ip6_tunnel, sit, ip6_gre, and ip_tunnel)
correctly set this flag during their fallback device initialization to
prevent them from being moved to another network namespace.
In the Linux kernel, the following vulnerability has been resolved:
wifi: ath5k: do not access array OOB
Vincent reports:
> The ath5k driver seems to do an array-index-out-of-bounds access as
> shown by the UBSAN kernel message:
> UBSAN: array-index-out-of-bounds in drivers/net/wireless/ath/ath5k/base.c:1741:20
> index 4 is out of range for type 'ieee80211_tx_rate [4]'
> ...
> Call Trace:
> <TASK>
> dump_stack_lvl+0x5d/0x80
> ubsan_epilogue+0x5/0x2b
> __ubsan_handle_out_of_bounds.cold+0x46/0x4b
> ath5k_tasklet_tx+0x4e0/0x560 [ath5k]
> tasklet_action_common+0xb5/0x1c0
It is real. 'ts->ts_final_idx' can be 3 on 5212, so:
info->status.rates[ts->ts_final_idx + 1].idx = -1;
with the array defined as:
struct ieee80211_tx_rate rates[IEEE80211_TX_MAX_RATES];
while the size is:
#define IEEE80211_TX_MAX_RATES 4
is indeed bogus.
Set this 'idx = -1' sentinel only if the array index is less than the
array size. As mac80211 will not look at rates beyond the size
(IEEE80211_TX_MAX_RATES).
Note: The effect of the OOB write is negligible. It just overwrites the
next member of info->status, i.e. ack_signal.
In the Linux kernel, the following vulnerability has been resolved:
spi: topcliff-pch: fix use-after-free on unbind
Give the driver a chance to flush its queue before releasing the DMA
buffers on driver unbind