kernel-4.18.0-553.184.2.el8_10

The kernel packages contain the Linux kernel, the core of any Linux operating
system.

Security fix(es):

- net: lock the socket in sock_gettstamp() (CVE-2026-98276)

CVE(s):
CVE-2026-98276
In the Linux kernel, the following vulnerability has been resolved: net: lock
the socket in sock_gettstamp() sk->sk_flags must only be changed while holding
the socket lock, because sock_set_flag() and sock_reset_flag() use non atomic
operations (__set_bit() and __clear_bit()). sock_gettstamp() is one of the last
places where a bit of sk->sk_flags is changed from a syscall without owning the
socket lock, through sock_enable_timestamp(sk, SOCK_TIMESTAMP).
sk_set_memalloc() and sk_clear_memalloc() also change sk->sk_flags without the
socket lock, but their callers (nbd, iscsi_tcp, nvme-tcp, sunrpc, wireguard)
need a careful audit, this will be addressed in a separate patch. Jungwoo Lee
and Wongi Lee reported an UDP socket use-after-free caused by this bug: a
SIOCGSTAMPNS_NEW ioctl racing with bind() can cancel the SOCK_RCU_FREE bit that
udp_lib_get_port() just set, because both threads perform a read-modify-write on
the same word. CPU 0 (bind) CPU 1 (SIOCGSTAMPNS_NEW)
-------------------------------- ---------------------------- read sk_flags = F
read sk_flags = F compute F | BIT(SOCK_RCU_FREE) compute F | BIT(SOCK_TIMESTAMP)
store F | BIT(SOCK_RCU_FREE) sk_add_node_rcu(sk, ...) store F |
BIT(SOCK_TIMESTAMP) After the lost update, SOCK_RCU_FREE is clear while the
socket is visible to lockless UDP receive lookups. sk_destruct() then frees the
socket immediately instead of waiting for a RCU grace period, while the receive
path still holds a reference-less pointer to it: BUG: KASAN: slab-use-after-free
in ipv4_pktinfo_prepare+0x30/0x410 Read of size 8 at addr ffff888008806610 by
task exploit/207 CPU: 0 UID: 1000 PID: 207 Comm: exploit Not tainted 6.12.95+ #1
ipv4_pktinfo_prepare+0x30/0x410 udp_queue_rcv_one_skb+0x51c/0x1180
udp_unicast_rcv_skb+0x109/0x350 ip_protocol_deliver_rcu+0x14b/0x310
ip_local_deliver_finish+0x29d/0x390 ip_local_deliver+0x24d/0x2a0 Only grab the
socket lock when SOCK_TIMESTAMP has to be set, to keep the common case lockless.