| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| 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: Check ancestor frames for rbtree callbacks
bpf_rbtree_add() invokes its comparator while the caller holds the root
lock. The native insertion code retains raw parent and link pointers across
the callback, so the verifier prohibits unlocking, consuming tree nodes,
or changing RCU state from that callback.
in_rbtree_lock_required_cb() only checks the innermost verifier frame.
Static subprogram calls are permitted while holding a spin lock, and such a
call pushes a frame without in_callback_fn set. Consequently, all callback
restrictions disappear in the nested frame. The subprogram can unlock the
tree, remove and drop the node being compared, then relock. Native insertion
resumes with the stale parent pointer and links freed memory into the tree.
Walk all active frames for the rbtree callback instead. Benign static
subprograms remain permitted, while callback restrictions follow execution
into nested frames. |
| In the Linux kernel, the following vulnerability has been resolved:
bpf: Mark bpf_btf_find_by_name_kind() as sleepable
When bpf_btf_find_by_name_kind() finds a type in module BTF, it
returns a new BTF object fd through __btf_new_fd(). This reaches
anon_inode_getfd(), which can sleep while allocating or expanding the
current task fd table.
The helper prototype does not set might_sleep, so the verifier allows
the helper in non-sleepable contexts such as BPF timer callbacks. The
fd allocation can then sleep in softirq context and install the fd into
the interrupted task.
Mark the helper as sleepable. This preserves calls from the main body
of a sleepable syscall program while rejecting calls from its
non-sleepable regions. |
| In the Linux kernel, the following vulnerability has been resolved:
bpf: Mark faultable stack helpers as sleepable
The faultable variants of bpf_get_stack() and bpf_get_task_stack() pass
may_fault=true into the common stack collection code. Resolving user-space
build IDs may then call build_id_parse_file() and block on filesystem
reads.
Neither helper prototype sets might_sleep. Since prototype selection uses
the sleepability of the whole program, the verifier can still allow these
helpers from a non-sleepable region within that program, such as an
explicit RCU or preemption-disabled region. The task-stack helper can also
be called from a non-sleepable timer callback of a sleepable program.
Mark both faultable prototypes as sleepable. The existing helper context
check then rejects these calls while continuing to allow them in genuinely
sleepable contexts. |
| In the Linux kernel, the following vulnerability has been resolved:
bpf: Reject legacy packet loads from callbacks
check_ld_abs() models a failed BPF_LD_ABS or BPF_LD_IND in a
subprogram as an implicit return with R0 set to zero. It calls
prepare_func_exit() to explore this synthesized path.
When the load is reached directly from a synchronous callback,
prepare_func_exit() enforces the callback return contract and marks R0
precise. R0 is not derived from a real instruction on this path, so
precision backtracking reaches the callback call with R0 still requested
and triggers the "callback unexpected regs" verifier bug. A privileged
program loader can therefore cause a verifier warning and an -EFAULT
BPF_PROG_LOAD.
These legacy packet-load instructions are deprecated. Reject them from
callbacks rather than complicating their implicit-return model. Check all
active frames before constructing the implicit return so nested static
subprograms cannot hide the callback context.
Global functions are verified independently with a fresh frame zero, so
an active-frame check cannot identify a global function called from a
callback. Also check the complete subprogram call graph during stack-depth
validation and reject a function containing a legacy load when any caller
is a callback. This covers global and static descendants without making
has_ld_abs transitive, preserving its per-function BTF return-type check.
Ordinary uses outside callbacks remain supported. |
| 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: Don't resurrect a scalar id dropped by collect_linked_regs()
check_cond_jmp_op() copies the compared registers into
env->{false,true}_reg{1,2} before collect_linked_regs() runs and copies
those snapshots back into both branch states afterwards.
collect_linked_regs() records at most LINKED_REGS_MAX members of a
linked registers group in the jump history and calls clear_scalar_id()
for every member that does not fit. The compared register is not exempt
from that.
As a consequence, sync_linked_regs() might adjust ranges for more
registers than bpf_bt_sync_linked_regs() can propagate precision to.
Collect the linked registers before the snapshots are taken instead.
This might lead to some unnecessary clear_scalar_id's, but from
previous testing situations with many linked registers are
extremely rare. |
| In the Linux kernel, the following vulnerability has been resolved:
bpf: Don't predict JMP32 pointer vs zero comparisons
Consider the following program:
r1 = map_value; /* low 32 bits are zero at runtime */
r6 = 0xdead000000000000;
if w1 != 0 goto l1;
l0: r1 += r6;
r2 = *(u64 *)(r1 + 0);
exit;
l1: r6 = 0;
goto l0;
At the moment is_branch_taken() reports the jump as always taken,
because it does not distinguish between BPF_JMP and BPF_JMP32
comparisons when processing 'if w1 != 0 ...'. |
| In the Linux kernel, the following vulnerability has been resolved:
bpf: Mark the zero register precise for a register-form NULL check
check_cond_jmp_op() accepts "if rA <op> rB" as a NULL check for a
nullable pointer rA when rB is a scalar known to be zero,
lifts PTR_MAYBE_NULL from rA in the corresponding branch and does not
mark rB precise. Consider the following program:
r0 = bpf_get_prandom_u32();
r6 = 1; /* the r6 == 0 path is explored first */
if (r0 == 0) goto 1f;
r6 = 0;
1:
r0 = bpf_map_lookup_elem(map, &0); /* absent, NULL at runtime */
if (r0 == r6) goto 2f; /* taken as a NULL check for r0 */
*(u8 *)(r0 + 0); /* verifier: map value; runtime: zero */
2:
return 0;
The r6 == 0 path is explored first and the dereference is accepted.
The r6 == 1 path is pruned at the checkpoint recorded for (1),
so the comparison is never verified with a non-zero r6. At runtime a
failed lookup returns NULL, NULL != 1 takes the non-NULL edge and the
program dereferences a pointer that is zero. |
| In the Linux kernel, the following vulnerability has been resolved:
bpf: Require MEM_PERCPU for percpu kptr stores
map_kptr_match_type() treats perm_flags as the set of register type flags
that a kptr field permits. Adding MEM_PERCPU to that set for
BPF_KPTR_PERCPU does not require the source register to carry it, however.
The subset test consequently accepts both a plain bpf_obj_new() allocation
and a referenced kernel pointer into a __percpu_kptr map field.
Loads from the field are always marked MEM_PERCPU. Consumers then treat the
stored value as the cookie returned by bpf_percpu_obj_new(): per-CPU pointer
helpers relocate it, and map teardown selects the per-CPU free path. A plain
allocation can therefore provide an arbitrary kernel read/write, while a
kernel pointer can be relocated into an invalid address or sent through a
missing destructor.
Require the source MEM_PERCPU flag to match the destination field kind.
This preserves valid bpf_percpu_obj_new() stores and rejects both the
program-BTF and kernel-BTF variants. |
| 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: Reject untrusted allocated-object pointers
When the final RCU read-side critical section ends, a local kptr is demoted
to PTR_UNTRUSTED but retains MEM_ALLOC. The pointer may be NULL or may refer
to an object whose lifetime is no longer protected.
type_is_ptr_alloc_obj() nevertheless recognizes any PTR_TO_BTF_ID with
MEM_ALLOC as a live allocated object. In particular, a refcount-only local
kptr never carries NON_OWN_REF, so it still passes the
bpf_refcount_acquire() argument check after RCU protection ends. The kfunc
can then dereference NULL or stale memory.
Make type_is_ptr_alloc_obj() reject PTR_UNTRUSTED pointers. Since
type_is_non_owning_ref() is based on the same predicate, graph kfunc
arguments obey the same live-object requirement. Fault-protected reads of
the demoted pointer remain valid: writes are already rejected, and read
fixups use bpf_may_fault_on_deref() rather than this predicate.
[ kkd: Rewrote commit log ] |
| In the Linux kernel, the following vulnerability has been resolved:
bpf: Preserve special fields in recycled rhtab elements
rhtab_map_update_elem() initializes special fields after obtaining an
element from bpf_mem_cache_alloc(). The allocator can return a fresh,
zeroed unit, or recycle one from its RCU-pending lists before the
registered destructor has run.
A BPF program can retain a map-value pointer after deleting its element
and initialize and arm a timer through that pointer. If the deleted unit
is recycled, check_and_init_map_value() clears the only pointer to the
timer. Neither a later deletion nor rhtab_mem_dtor() can then cancel it,
and the callback can run with its key and value pointing into freed memory.
Do not reinitialize special fields on insertion. Fresh allocator units are
already zeroed. For recycled units, the special fields are ownership state
that must remain visible to the eventual destructor. copy_map_value()
already skips those fields, matching the non-preallocated hash-map path and
the lifecycle established by commit 275c30bcee66 ("bpf: Don't reinit map
value in prealloc_lru_pop").
[ kkd: Split out the fix and rewrote the commit log ] |
| In the Linux kernel, the following vulnerability has been resolved:
bpf: Cancel special fields when recycling rhtab elements
rhtab_map_update_existing() and rhtab_delete_elem() call
bpf_obj_free_fields() when replacing or deleting a value. These map
operations can run from BPF programs in NMI context, where releasing a
referenced kptr or another complex field is not generally safe.
Array and hash maps avoid that problem by cancelling only the asynchronous
fields which can be stopped safely in the caller context. Other ownership
state remains attached to the allocation until its memory allocator
destructor performs the final cleanup.
Use bpf_obj_cancel_fields() for the corresponding rhtab paths as well. This
cancels timers, workqueues, and task work while allowing rhtab_mem_dtor() to
release referenced kptrs when the allocation is eventually destroyed.
[ kkd: Rebased, used direct helper calls, and rewrote the 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:
nexthop: Initialize extack in remove_nh_grp_entry()
remove_nh_grp_entry() prints the extack message when a listener fails
to replace the reduced nexthop group. However, extack is not
initialized and listeners are not required to set a message when
returning an error. Neither netdevsim nor mlxsw do so when an
allocation fails, resulting in the dereference of an uninitialized
stack pointer.
Fix by zero-initializing extack, as was done in commit 6347c5314cee
("nexthop: initialize extack in nh_res_bucket_migrate()"). |
| In the Linux kernel, the following vulnerability has been resolved:
net: dsa: bcm_sf2: bound the CFP rule dump by the caller's buffer size
bcm_sf2_cfp_rule_get_all() walks the whole cfp.unique bitmap into
rule_locs[] without consulting nfc->rule_cnt, which is how many entries
the caller had room for. ETHTOOL_GRXCLSRLALL requires no CAP_NET_ADMIN
and the ioctl sizes the buffer from the rule_cnt userspace passes in, so
once an admin has installed CFP rules any user can ask for fewer slots
than there are rules and run off the end of the allocation. A rule_cnt
of 0 leaves the buffer pointer NULL and the walk dereferences it. |
| In the Linux kernel, the following vulnerability has been resolved:
eth: nfp: bound the ntuple rule dump by the caller's buffer size
nfp_net_get_fs_loc() dumps every entry of nn->fs.list into rule_locs[]
without consulting cmd->rule_cnt, which is how many entries the caller
had room for. ETHTOOL_GRXCLSRLALL requires no CAP_NET_ADMIN and the
ioctl sizes the buffer from the rule_cnt userspace passes in, so once an
admin has installed flow steering rules any user can ask for fewer slots
than there are rules and run off the end of the allocation. A rule_cnt
of 0 leaves the buffer pointer NULL and the walk dereferences it.
Bail out with -EMSGSIZE when the buffer fills up, the way the other
ntuple capable drivers do, and report how many locations were filled so
a shrinking rule list does not leave the caller reading stale slots. |
