| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| In the Linux kernel, the following vulnerability has been resolved:
xen/netfront: drop RX packets with a short Ethernet header
handle_incoming_queue() pulls pull_to bytes into the head before
calling eth_type_trans(). pull_to is the length of the first RX slot,
capped at RX_COPY_THRESHOLD, and that length comes from the backend.
Nothing checks it against ETH_HLEN.
If the first slot is shorter than ETH_HLEN and more slots follow, the
head ends up shorter than an Ethernet header while skb->len is longer,
and eth_type_trans() BUG()s in __skb_pull(). If the whole packet is
shorter than ETH_HLEN, eth_type_trans() reads the header past the end
of the data instead.
Pull at least ETH_HLEN, and drop the packet if that fails, which also
drops packets too short to hold an Ethernet header. This also checks
the return value of the pull, which was ignored. |
| In the Linux kernel, the following vulnerability has been resolved:
smb/server: fix tree connection leak in smb2_tree_connect()
See the procedure below:
smb2_tree_connect
ksmbd_tree_conn_connect
xa_store(&sess->tree_conns, tree_conn->id, tree_conn)
ksmbd_counter_inc(KSMBD_COUNTER_TREE_CONNS)
ksmbd_share_tree_conn_inc(sc)
ksmbd_iov_pin_rsp // fail
status.ret = KSMBD_TREE_CONN_STATUS_NOMEM
// do not disconnect tree_conn
Disconnect the new tree connection if ksmbd_iov_pin_rsp() fails. |
| In the Linux kernel, the following vulnerability has been resolved:
printk: Don't WARN on kthread_run failure.
Since __kthread_create_on_node() returns -EINTR upon SIGKILL,
we should not use WARN_ON() in order to catch kthread_run() failure. |
| In the Linux kernel, the following vulnerability has been resolved:
bpf: check_cond_jmp_op(): properly infer if register is null
Nicholas Carlini reported a bug when verifier can incorrectly infer
that a pointer is non-null. The bug occurs when two pointers are
compared and one of them has a type w/o PTR_MAYBE_NULL flag,
but which allows a value to be NULL at runtime.
Here is an example:
// `a` is PTR_TO_MEM | MEM_RDONLY | PTR_UNTRUSTED
// `a` is 0 at runtime.
// `b` is PTR_TO_MAP_VALUE | PTR_MAYBE_NULL
void *a = bpf_rdonly_cast(0, 0);
int *b = bpf_map_lookup_elem(...);
if (a == b)
*b = 42; // verifier does not catch null pointer dereference
This happens because of a special case in check_cond_jmp_op(),
which attempts to strip PTR_MAYBE_NULL flags from pointer types,
when processing comparisons like `rA == rB`, if either rA or rB can't
be null.
The non-null property is derived based on the absence of
PTR_MAYBE_NULL flag on rA's or rB's type. But that is not sufficient
for types like PTR_TO_MEM, as in the example.
This patch replaces type_may_be_null() call with reg_not_null(),
which contains an allowlist of types for which absence of
PTR_MAYBE_NULL actually means that the value can't be NULL at runtime.
At the moment, the list in the reg_not_null() omits two types for
which PTR_MAYBE_NULL is applicable: PTR_TO_XDP_SOCK and PTR_TO_BUF.
In order to remain backward compatible, and assuming that only
comparison between pointers of the same type makes sense,
this commit extends reg_not_null(). W/o such an extension e.g.
verifier_jeq_infer_not_null/null_ptr_to_map_value fails.
reg_not_null() can be extended further, but I deem that out of scope
for the fix at hand. Explicit base_type(...) != PTR_TO_BTF_ID
checks in the check_cond_jmp_op() can be removed with migration to
reg_not_null(), but that is a behavioural change, as the special case
would start matching for PTR_TO_BTF_ID that is also is_trusted_reg().
I omit the behavioural change from this commit. |
| In the Linux kernel, the following vulnerability has been resolved:
net: stmmac: fix dma mapping leak in stmmac_tso_xmit()
In stmmac_tso_xmit(), if the DMA mapping of an skb fragment fails, the
frame is dropped but the DMA mappings already created for the linear
part and for the fragments mapped before the failure are never
unmapped, leaking DMA mappings.
Fix the leak by walking back over the descriptors used by the frame and
releasing each of them with stmmac_free_tx_buffer(). Moreover, release
the descriptors with stmmac_release_tx_desc() unmapping the DMA buffers. |
| In the Linux kernel, the following vulnerability has been resolved:
ipv6: mcast: use rcu_assign_pointer() for __rcu list updates
Several places in net/ipv6/mcast.c update RCU-protected lists
(np->ipv6_mc_list, idev->mc_list, idev->mc_tomb) using direct pointer
assignments instead of rcu_assign_pointer():
1. In __ipv6_dev_mc_dec(), unlinking a group from idev->mc_list did:
*map = ma->next;
without rcu_assign_pointer() while concurrent readers traverse
idev->mc_list locklessly under rcu_read_lock().
2. In ipv6_sock_mc_drop() and __ipv6_sock_mc_close(), unlinking a group
from np->ipv6_mc_list directly assigned *lnk = mc_lst->next and
np->ipv6_mc_list = mc_lst->next without rcu_assign_pointer(), racing
with lockless readers in inet6_mc_check().
3. In __ipv6_sock_mc_join(), mc_lst->next was initialized to
np->ipv6_mc_list via raw assignment before publishing mc_lst.
4. In mld_del_delrec() and __ipv6_dev_mc_inc(), __rcu source pointers
passed into rcu_assign_pointer() lacked explicit dereference helpers.
Fix these by consistently using rcu_assign_pointer() along with
mc_dereference() / sock_dereference(). |
| In the Linux kernel, the following vulnerability has been resolved:
bpf: backtrack_insn(): Handle ld_{abs,ind} subprog exit edge
Nicholas Carlini reported a bug in precision backtracking mechanism
for BPF_LD | BPF_{IND,ABS} instructions. These instructions are
modelled as two branches:
- fallthrough;
- implicit exit from current subprogram.
The implicit exit case was not handled by the backtrack_insn()
function. When backtracking such a path backtrack_insn() did not
call bt_subprog_enter(), which meant that backtracking continued
manipulating precision marks in a caller frame, while looking at
instructions in a callee frame.
This lead to segmentation faults during verification (see the
selftest), or unsound state pruning. |
| In the Linux kernel, the following vulnerability has been resolved:
bpf: backtracking shouldn't clear outer frame R1-R5 for callbacks
When processing calls to bpf_loop() verifier marks R1 (and R4) as
precise. R1 tracks loop iterations number and because of the
'callback_depth < R1' mechanics in check_helper_call() must be marked
precise. However, precision propagation for R1 was broken,
when bpf_loop() call was verified on a second iteration.
Consider the following verification trace:
- main: bpf_loop(nr_loops, callback ...)
- callback: BPF_EXIT
- main: bpf_loop(nr_loops, callback ...)
- ...
While the first visit of the call to bpf_loop() propagated R1
precision as expected, the second call to mark_chain_precision() in
the check_helper_call() set R1, but it was immediately reset when
backtrack_insn() processed preceding BPF_EXIT in the loop deleted in
this patch.
Because of that, the second visit of the call to bpf_loop() injected
checkpoint with R1 not marked as precise. Which could trick the
verifier into accepting unsafe programs. See the next patch for an
example of such program.
Commit is structured in a way to minimize conflicts when
'bpf' would be eventually merged with 'bpf-next'. |
| In the Linux kernel, the following vulnerability has been resolved:
bpf: Mark syscall helpers as sleepable
bpf_sys_bpf() executes the bpf(2) syscall body, which can take mutexes,
allocate with GFP_KERNEL, and wait for an RCU grace period.
bpf_sys_close() reaches close_fd() and filp_close(), which can sleep as
well.
Both helpers are limited to BPF_PROG_TYPE_SYSCALL, whose main program is
sleepable. That does not make every callback sleepable: a syscall program
can register a bpf_timer callback, and the verifier checks that callback
in a non-sleepable context while retaining the syscall helper set.
Without .might_sleep on the prototypes, such a callback can invoke
bpf_sys_bpf() from hrtimer softirq context and trigger a
scheduling-while-atomic failure. bpf_sys_close() is exposed through the
same missing context check.
Set .might_sleep on both prototypes so the existing helper-context check
rejects them from timer callbacks and other atomic regions. Calls from the
sleepable main body remain valid. |
| In the Linux kernel, the following vulnerability has been resolved:
ring-buffer: Add checking nr_subbufs to persistent ring buffer validation
Sashiko reported that the code was using meta->nr_subbufs without making
sure that it matched the nr_pages + 1 on data that was assuming the two
were the same.
Add a check to the persistent ring buffer validation code to make sure
that the saved nr_subbufs matches what we expect. |
| In the Linux kernel, the following vulnerability has been resolved:
bpf: zero extend the result of an arena 32-bit cmpxchg
bpf_convert_ctx_accesses() rewrites an atomic on an arena pointer from
BPF_STX | BPF_ATOMIC to BPF_STX | BPF_PROBE_ATOMIC, and it runs before
bpf_opt_subreg_zext_lo32_rnd_hi32().
That pass emits an explicit zero extension for a 32-bit cmpxchg even
when bpf_jit_needs_zext() is false. This is done because on some
architectures 32-bit cmpxchg requires explicit zero extension for the
dst register. E.g. on x86-64 'lock cmpxchg' does not change the %eax
if comparison is successful, while BPF semantics declare that each
operation on a 32-bit register zero extends it's upper half.
is_cmpxchg_insn() matches BPF_MODE == BPF_ATOMIC only, so an arena
cmpxchg misses said zero extension adjustment. This patch adjusts
is_cmpxchg_insn() to match BPF_PROBE_ATOMIC alongside BPF_ATOMIC. |
| In the Linux kernel, the following vulnerability has been resolved:
bpf: don't rewrite bpf_fastcall patterns entered by a jump
mark_fastcall_pattern_for_call() must ensure that matched
"spill; call; fill" instruction series is not interrupted by a jump.
Otherwise the rewrite applied by bpf_remove_fastcall_spills_fills()
is not sound.
Record the instructions targeted by jumps in
insn_aux_data[*].jump_target when the CFG is built and use this flag
to stop growing a pattern at such an instruction. Jumps to the first
spill are fine.
Note that existing insn_aux_data[*].jmp_point field can't be reused,
as it marks subprogram return instructions. |
| In the Linux kernel, the following vulnerability has been resolved:
bpf: Don't infer non-NULL from a pointer with an unbounded offset
reg_not_null() decides that a register holds a non-NULL value by
looking at its type alone. For pointer types that allow arithmetic the
type only guarantees a non-NULL base, in case of an unbound offset
the runtime offset value might still add up to NULL.
Consider the followng program:
r6 = bpf_map_lookup_elem(map, &0); /* present */
if (r6 == 0) return 0;
r7 = bpf_map_lookup_elem(map, &1); /* absent, NULL at runtime */
r8 = r7;
r8 -= r6; /* pointer - pointer: unknown scalar, -r6 */
r8 <<= 1;
r8 >>= 1; /* any non-negative offset is accepted by */
/* check_reg_sane_offset_ptr() */
r6 += r8; /* verifier: map value; runtime: zero */
if (r7 != r6) return 0;
*(u8 *)(r7 + 0); /* r7 is inferred non-NULL, both are zero */
At runtime both registers are zero, the comparison is true and the
load faults with NULL pointer dereference.
Require the offset to be within +-BPF_MAX_VAR_OFF in reg_not_null(). |
| In the Linux kernel, the following vulnerability has been resolved:
bpf: Keep refcount_acquire nullable for borrowed RCU kptrs
bpf_refcount_acquire() is fallible for a borrowed reference because the
object may have reached a zero refcount. The verifier therefore keeps
KF_RET_NULL on the return value unless the argument is an owning reference.
An RCU-protected load of a local kptr is marked MEM_ALLOC, but it only
receives NON_OWN_REF when the pointee contains a graph node. A refcounted
object without a graph node consequently looks like an owning reference
even though the loaded register has no acquired reference state. If the
program drops the last real reference while remaining in the RCU critical
section, refcount_inc_not_zero() returns NULL while the verifier treats the
result as non-NULL.
Only classify the argument as owning when it is backed by a verifier-tracked
reference. This retains the non-NULL return for pointers from bpf_obj_new(),
bpf_kptr_xchg(), or an earlier successful acquisition, while requiring a
NULL check for borrowed RCU kptrs.
[ kkd: Rewrote commit log ] |
| In the Linux kernel, the following vulnerability has been resolved:
bpf: Mark NULL kptr stores precise
check_map_kptr_access() permits a scalar store into an untrusted kptr
field only when the register is known to contain zero. Unlike other
verifier checks whose outcome depends on a scalar value, it does not mark
that register precise.
A state checkpoint reached with an imprecise zero can therefore prune a
second path that reaches the store with an arbitrary nonzero scalar. The
program can write attacker-controlled bits into the kptr field and load
them back as a PTR_TO_BTF_ID.
Call mark_chain_precision() before accepting a known-zero register. This
forces state equivalence to compare its scalar range and makes the verifier
visit and reject a path carrying a nonzero value. |
| In the Linux kernel, the following vulnerability has been resolved:
bpf: Preserve inner map identity in callback frames
Callback frame constructors initialize map-typed argument registers with
__mark_reg_known_zero() and then restore map_ptr. This clears map_uid,
which is the only field distinguishing inner maps that share an
inner_map_meta template.
When a timer callback invokes bpf_for_each_map_elem() on a second inner
map, both the saved first map and the second map value can reach the nested
callback as the same template with map_uid zero. bpf_timer_init() then
accepts pairing the timer from the second map with the first map.
The runtime records the first map in the timer without taking a reference.
Freeing that map does not find the timer stored in the second map, so a
later timer callback dereferences the freed map.
Copy map_uid from the same caller register as map_ptr when constructing
for-each, timer/workqueue, and task-work callback arguments. The existing
identity check can then reject mismatched inner maps while allowing a
callback value to be paired with its actual map. |
| In the Linux kernel, the following vulnerability has been resolved:
tracing: Fix subbuf resize races with trace_pipe_raw readers
Concurrent subbuffer resizes may crash trace_pipe_raw readers or leak
uninitialized memory to userspace due to stale size values.
Modify ring_buffer_alloc_read_page() to handle the resizing of an
existing buffer_data_read_page if necessary and add a new
ring_buffer_read_page_size(). This new function enables ring-buffer
buffer_data_read_page users to not call the racy
ring_buffer_subbuf_size_get(). This makes the spare_size member of
ftrace_buffer_info redundant.
Finally, handle buffer_data_read_page/reader_page order discrepancy in
ring_buffer_read_page(). On a mismatch simply copy manually the data to
the buffer_data_read_page. |
| In the Linux kernel, the following vulnerability has been resolved:
bpf: mark a NULL call argument precise
check_func_arg() allows bpf_register_is_null() for nullable arguments
w/o marking the underlying scalar register precise. Hence a checkpoint
created on such a path would prune against arbitrary scalar value.
check_helper_call() enforces second parameter of the
bpf_get_local_storage() to be zero, w/o marking the underlying scalar
register precise. Hence a checkpoint created on such a path would
prune against arbitrary scalar value.
Grouping these two into one patch, as they share the same fixes tag. |
| In the Linux kernel, the following vulnerability has been resolved:
iommu/riscv: Serialize command queue publishing
Serialize command queue publishing so software producer state advances only
after a command is written and the hardware tail is updated. Wait for
hardware consumption outside the queue lock when the command queue is full
so other CPUs are not blocked behind a long poll. |
| In the Linux kernel, the following vulnerability has been resolved:
virtio_ring: fix stale descriptor flags after a failed packed add
In a packed ring the AVAIL and USED bits sit in the descriptor itself,
so writing them makes that descriptor available. Those bit combinations
flip meaning on every round of the ring, tracked by a wrap counter, so
invalidating or validating a descriptor means inverting both bits.
Commit 1ce9e6055fa0 ("virtio_ring: introduce packed ring support") has
virtqueue_add_packed() make every descriptor of a chain available as it
maps the chain, and write the head last. The device consumes the ring in
order and stops at a head that is not available yet, so it never reaches
the rest.
When vring_map_one_sg() fails partway, unmap_release unmaps the segments
and restores avail_used_flags, but the descriptors it wrote to in the
ring stay marked with AVAIL and USED bits. The head is now the only
entry that keeps the device from consuming these stale entries.
For example, the ring would look like this now.
Z - pre-previous command
A - previous command
B - aborted command
C - current command
[A1 DONE] [A2 DONE] <C1 EMPTY> [B2] [B3] [Z1 DONE]
When the driver now attempts to issue the C command, the next add starts
at the same head as B. If C spans less descriptors than B, there is no
end marker because AVAIL and USED bits were still in place. And that
means the device will start interpreting these stale entries (B2/B3) as
another command entry, which then blocks the queue.
This effect typically happens in swiotlb configurations under memory
pressure, because vring_map_one_sg() can then fail with larger I/O
requests which then leads to command abortions.
There are broadly 2 ways to avoid leaving those flags behind:
1) Defer those flags too until the chain is complete.
2) Rewrite those flags for the previous wrap counter.
Implement the second option in both packed add paths. The first option
traverses the chain a second time on every successful add. The second
option invalidates all added descriptors when any add fails.
With this patch applied, a packed virtqueue keeps completing requests
after a failed add. |
