Описание
In the Linux kernel, the following vulnerability has been resolved:
net/iucv: fix the recvmsg window update
iucv_sock_recvmsg() sends the HiperSockets-only AF_IUCV_FLAG_WIN without
testing the transport, so on a classic z/VM socket iucv_send_ctrl() sizes
the skb through a NULL iucv->hs_dev. SO_MSGLIMIT accepts 1, so msglimit / 2
is zero and one recvmsg() on its own socket is enough for an unprivileged
process to take a spurious disconnect.
It also calls iucv_send_ctrl() under spin_lock_bh(&message_q.lock), which
allocates GFP_KERNEL inside a section the code treats as atomic. Sending
outside that lock lets two recvmsg() reach afiucv_hs_send() at once, where
msg_recv is sampled for the advertised window and subtracted after
dev_queue_xmit() -- and sendmsg reaches that counter under lock_sock()
while recvmsg holds no socket lock, so both can subtract the same value,
the counter goes negative and the credit reaches the peer twice.
Test the transport, claim the credit with atomic_xchg() after the last
error exit and hand it back if the transmit fails, and send once the lock
is dropped.
A flaw was found in the Linux kernel's IUCV (Inter-User Communication Vehicle) networking subsystem. A local attacker can exploit this flaw to cause a Denial of Service (DoS) through a kernel crash or unexpected socket disconnection. The vulnerability is triggered when processing message receive requests without properly verifying the socket transport type or managing internal locks during receive window updates.
Затронутые пакеты
| Платформа | Пакет | Состояние | Рекомендация | Релиз |
|---|---|---|---|---|
| Red Hat Enterprise Linux 10 | kernel | Fix deferred | ||
| Red Hat Enterprise Linux 6 | kernel | Out of support scope | ||
| Red Hat Enterprise Linux 7 | kernel | Fix deferred | ||
| Red Hat Enterprise Linux 7 | kernel-rt | Fix deferred | ||
| Red Hat Enterprise Linux 8 | kernel | Fix deferred | ||
| Red Hat Enterprise Linux 8 | kernel-rt | Fix deferred | ||
| Red Hat Enterprise Linux 9 | kernel | Fix deferred | ||
| Red Hat Enterprise Linux 9 | kernel-rt | Fix deferred | ||
| Red Hat OpenShift Container Platform 4 | openshift/ose-rhel-coreos-8 | Fix deferred | ||
| Red Hat OpenShift Container Platform 4 | openshift/ose-rhel-coreos-9 | Fix deferred |
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Дополнительная информация
Статус:
EPSS
5.5 Medium
CVSS3
Связанные уязвимости
In the Linux kernel, the following vulnerability has been resolved: net/iucv: fix the recvmsg window update iucv_sock_recvmsg() sends the HiperSockets-only AF_IUCV_FLAG_WIN without testing the transport, so on a classic z/VM socket iucv_send_ctrl() sizes the skb through a NULL iucv->hs_dev. SO_MSGLIMIT accepts 1, so msglimit / 2 is zero and one recvmsg() on its own socket is enough for an unprivileged process to take a spurious disconnect. It also calls iucv_send_ctrl() under spin_lock_bh(&message_q.lock), which allocates GFP_KERNEL inside a section the code treats as atomic. Sending outside that lock lets two recvmsg() reach afiucv_hs_send() at once, where msg_recv is sampled for the advertised window and subtracted after dev_queue_xmit() -- and sendmsg reaches that counter under lock_sock() while recvmsg holds no socket lock, so both can subtract the same value, the counter goes negative and the credit reaches the peer twice. Test the transport, claim the credit with atomic_xchg()...
In the Linux kernel, the following vulnerability has been resolved: net/iucv: fix the recvmsg window update iucv_sock_recvmsg() sends the HiperSockets-only AF_IUCV_FLAG_WIN without testing the transport, so on a classic z/VM socket iucv_send_ctrl() sizes the skb through a NULL iucv->hs_dev. SO_MSGLIMIT accepts 1, so msglimit / 2 is zero and one recvmsg() on its own socket is enough for an unprivileged process to take a spurious disconnect. It also calls iucv_send_ctrl() under spin_lock_bh(&message_q.lock), which allocates GFP_KERNEL inside a section the code treats as atomic. Sending outside that lock lets two recvmsg() reach afiucv_hs_send() at once, where msg_recv is sampled for the advertised window and subtracted after dev_queue_xmit() -- and sendmsg reaches that counter under lock_sock() while recvmsg holds no socket lock, so both can subtract the same value, the counter goes negative and the credit reaches the peer twice. Test the transport, claim the credit with atomic_xchg(
In the Linux kernel, the following vulnerability has been resolved: n ...
In the Linux kernel, the following vulnerability has been resolved: net/iucv: fix the recvmsg window update iucv_sock_recvmsg() sends the HiperSockets-only AF_IUCV_FLAG_WIN without testing the transport, so on a classic z/VM socket iucv_send_ctrl() sizes the skb through a NULL iucv->hs_dev. SO_MSGLIMIT accepts 1, so msglimit / 2 is zero and one recvmsg() on its own socket is enough for an unprivileged process to take a spurious disconnect. It also calls iucv_send_ctrl() under spin_lock_bh(&message_q.lock), which allocates GFP_KERNEL inside a section the code treats as atomic. Sending outside that lock lets two recvmsg() reach afiucv_hs_send() at once, where msg_recv is sampled for the advertised window and subtracted after dev_queue_xmit() -- and sendmsg reaches that counter under lock_sock() while recvmsg holds no socket lock, so both can subtract the same value, the counter goes negative and the credit reaches the peer twice. Test the transport, claim the credit with atomic_xc...
EPSS
5.5 Medium
CVSS3