Linux: >> Linux Kernel >> 6.1.59 Security Vulnerabilities
In the Linux kernel, the following vulnerability has been resolved:
bpf: track changes_pkt_data property for global functions
When processing calls to certain helpers, verifier invalidates all
packet pointers in a current state. For example, consider the
following program:
__attribute__((__noinline__))
long skb_pull_data(struct __sk_buff *sk, __u32 len)
{
return bpf_skb_pull_data(sk, len);
}
SEC("tc")
int test_invalidate_checks(struct __sk_buff *sk)
{
int *p = (void *)(long)sk->data;
if ((void *)(p + 1) > (void *)(long)sk->data_end) return TCX_DROP;
skb_pull_data(sk, 0);
*p = 42;
return TCX_PASS;
}
After a call to bpf_skb_pull_data() the pointer 'p' can't be used
safely. See function filter.c:bpf_helper_changes_pkt_data() for a list
of such helpers.
At the moment verifier invalidates packet pointers when processing
helper function calls, and does not traverse global sub-programs when
processing calls to global sub-programs. This means that calls to
helpers done from global sub-programs do not invalidate pointers in
the caller state. E.g. the program above is unsafe, but is not
rejected by verifier.
This commit fixes the omission by computing field
bpf_subprog_info->changes_pkt_data for each sub-program before main
verification pass.
changes_pkt_data should be set if:
- subprogram calls helper for which bpf_helper_changes_pkt_data
returns true;
- subprogram calls a global function,
for which bpf_subprog_info->changes_pkt_data should be set.
The verifier.c:check_cfg() pass is modified to compute this
information. The commit relies on depth first instruction traversal
done by check_cfg() and absence of recursive function calls:
- check_cfg() would eventually visit every call to subprogram S in a
state when S is fully explored;
- when S is fully explored:
- every direct helper call within S is explored
(and thus changes_pkt_data is set if needed);
- every call to subprogram S1 called by S was visited with S1 fully
explored (and thus S inherits changes_pkt_data from S1).
The downside of such approach is that dead code elimination is not
taken into account: if a helper call inside global function is dead
because of current configuration, verifier would conservatively assume
that the call occurs for the purpose of the changes_pkt_data
computation.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-05-05
In the Linux kernel, the following vulnerability has been resolved:
bpf: check changes_pkt_data property for extension programs
When processing calls to global sub-programs, verifier decides whether
to invalidate all packet pointers in current state depending on the
changes_pkt_data property of the global sub-program.
Because of this, an extension program replacing a global sub-program
must be compatible with changes_pkt_data property of the sub-program
being replaced.
This commit:
- adds changes_pkt_data flag to struct bpf_prog_aux:
- this flag is set in check_cfg() for main sub-program;
- in jit_subprogs() for other sub-programs;
- modifies bpf_check_attach_btf_id() to check changes_pkt_data flag;
- moves call to check_attach_btf_id() after the call to check_cfg(),
because it needs changes_pkt_data flag to be set:
bpf_check:
... ...
- check_attach_btf_id resolve_pseudo_ldimm64
resolve_pseudo_ldimm64 --> bpf_prog_is_offloaded
bpf_prog_is_offloaded check_cfg
check_cfg + check_attach_btf_id
... ...
The following fields are set by check_attach_btf_id():
- env->ops
- prog->aux->attach_btf_trace
- prog->aux->attach_func_name
- prog->aux->attach_func_proto
- prog->aux->dst_trampoline
- prog->aux->mod
- prog->aux->saved_dst_attach_type
- prog->aux->saved_dst_prog_type
- prog->expected_attach_type
Neither of these fields are used by resolve_pseudo_ldimm64() or
bpf_prog_offload_verifier_prep() (for netronome and netdevsim
drivers), so the reordering is safe.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-05-05
In the Linux kernel, the following vulnerability has been resolved:
wifi: mt76: do not run mt76_unregister_device() on unregistered hw
Trying to probe a mt7921e pci card without firmware results in a
successful probe where ieee80211_register_hw hasn't been called. When
removing the driver, ieee802111_unregister_hw is called unconditionally
leading to a kernel NULL pointer dereference.
Fix the issue running mt76_unregister_device routine just for registered
hw.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-05-02
In the Linux kernel, the following vulnerability has been resolved:
net_sched: hfsc: Fix a UAF vulnerability in class handling
This patch fixes a Use-After-Free vulnerability in the HFSC qdisc class
handling. The issue occurs due to a time-of-check/time-of-use condition
in hfsc_change_class() when working with certain child qdiscs like netem
or codel.
The vulnerability works as follows:
1. hfsc_change_class() checks if a class has packets (q.qlen != 0)
2. It then calls qdisc_peek_len(), which for certain qdiscs (e.g.,
codel, netem) might drop packets and empty the queue
3. The code continues assuming the queue is still non-empty, adding
the class to vttree
4. This breaks HFSC scheduler assumptions that only non-empty classes
are in vttree
5. Later, when the class is destroyed, this can lead to a Use-After-Free
The fix adds a second queue length check after qdisc_peek_len() to verify
the queue wasn't emptied.
CVSS Score
7.8
EPSS Score
0.001
Published
2025-05-02
In the Linux kernel, the following vulnerability has been resolved:
codel: remove sch->q.qlen check before qdisc_tree_reduce_backlog()
After making all ->qlen_notify() callbacks idempotent, now it is safe to
remove the check of qlen!=0 from both fq_codel_dequeue() and
codel_qdisc_dequeue().
CVSS Score
7.8
EPSS Score
0.001
Published
2025-05-02
In the Linux kernel, the following vulnerability has been resolved:
wifi: at76c50x: fix use after free access in at76_disconnect
The memory pointed to by priv is freed at the end of at76_delete_device
function (using ieee80211_free_hw). But the code then accesses the udev
field of the freed object to put the USB device. This may also lead to a
memory leak of the usb device. Fix this by using udev from interface.
CVSS Score
7.8
EPSS Score
0.001
Published
2025-05-01
In the Linux kernel, the following vulnerability has been resolved:
net: dsa: mv88e6xxx: avoid unregistering devlink regions which were never registered
Russell King reports that a system with mv88e6xxx dereferences a NULL
pointer when unbinding this driver:
https://lore.kernel.org/netdev/Z_lRkMlTJ1KQ0kVX@shell.armlinux.org.uk/
The crash seems to be in devlink_region_destroy(), which is not NULL
tolerant but is given a NULL devlink global region pointer.
At least on some chips, some devlink regions are conditionally registered
since the blamed commit, see mv88e6xxx_setup_devlink_regions_global():
if (cond && !cond(chip))
continue;
These are MV88E6XXX_REGION_STU and MV88E6XXX_REGION_PVT. If the chip
does not have an STU or PVT, it should crash like this.
To fix the issue, avoid unregistering those regions which are NULL, i.e.
were skipped at mv88e6xxx_setup_devlink_regions_global() time.
CVSS Score
5.5
EPSS Score
0.001
Published
2025-05-01
In the Linux kernel, the following vulnerability has been resolved:
cxgb4: fix memory leak in cxgb4_init_ethtool_filters() error path
In the for loop used to allocate the loc_array and bmap for each port, a
memory leak is possible when the allocation for loc_array succeeds,
but the allocation for bmap fails. This is because when the control flow
goes to the label free_eth_finfo, only the allocations starting from
(i-1)th iteration are freed.
Fix that by freeing the loc_array in the bmap allocation error path.
CVSS Score
5.5
EPSS Score
0.001
Published
2025-05-01
In the Linux kernel, the following vulnerability has been resolved:
net: openvswitch: fix nested key length validation in the set() action
It's not safe to access nla_len(ovs_key) if the data is smaller than
the netlink header. Check that the attribute is OK first.
CVSS Score
7.8
EPSS Score
0.001
Published
2025-05-01
In the Linux kernel, the following vulnerability has been resolved:
net: mctp: Set SOCK_RCU_FREE
Bind lookup runs under RCU, so ensure that a socket doesn't go away in
the middle of a lookup.
CVSS Score
5.5
EPSS Score
0.001
Published
2025-05-01