Описание
In the Linux kernel, the following vulnerability has been resolved:
net: bridge: mcast: don't truncate the port group walk on teardown
__br_multicast_disable_port_ctx() and br_multicast_del_port() walk
port->mglist with hlist_for_each_entry_safe(). However,
br_multicast_find_del_pg() can also delete other entries from the same
list through br_multicast_fwd_src_remove() or __fwd_del_star_excl().
If such an entry is the iterator's saved next node, hlist_del_init()
clears its ->next and terminates the walk early. The reproducer triggers
this in both teardown walks, leaving port groups in the bridge mdb with
a dangling ->key.port after del_nbp() frees the port:
BUG: KASAN: slab-use-after-free in __mdb_fill_info+0x1191/0x1320
__mdb_fill_info+0x1191/0x1320
br_mdb_dump+0x594/0xe40
rtnl_mdb_dump+0x1cf/0x5d0
Use hlist_del_init_rcu() to unlink the group while preserving ->next.
br_multicast_del_pg() and the teardown walks run under
br->multicast_lock. The GC worker must acquire the same lock before
detaching the group for destruction, so the node remains alive while
the walk uses the preserved pointer.
Preserving ->next means a walk can now reach a group that an earlier
iteration already deleted as a side effect. That group is off mp->ports,
so br_multicast_find_del_pg() would fall through its port scan and hit
the trailing WARN_ON(1). Skip such groups at the top of that helper: a
port group is put on port->mglist when it is created and only unlinked
when it is deleted, so hlist_unhashed() identifies exactly this case.
A flaw was found in the Linux kernel's network bridge multicast subsystem. During network bridge port removal, the cleanup process can terminate prematurely, leaving behind orphaned records pointing to deallocated memory. A local attacker with network administration privileges can trigger this flaw to cause a use-after-free condition, where the operating system attempts to access memory that has already been released. This flaw primarily leads to a system crash resulting in a Denial of Service (DoS), and could potentially enable memory corruption or privilege escalation.
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 | Not affected | ||
| Red Hat Enterprise Linux 7 | kernel-rt | Not affected | ||
| 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: bridge: mcast: don't truncate the port group walk on teardown __br_multicast_disable_port_ctx() and br_multicast_del_port() walk port->mglist with hlist_for_each_entry_safe(). However, br_multicast_find_del_pg() can also delete other entries from the same list through br_multicast_fwd_src_remove() or __fwd_del_star_excl(). If such an entry is the iterator's saved next node, hlist_del_init() clears its ->next and terminates the walk early. The reproducer triggers this in both teardown walks, leaving port groups in the bridge mdb with a dangling ->key.port after del_nbp() frees the port: BUG: KASAN: slab-use-after-free in __mdb_fill_info+0x1191/0x1320 __mdb_fill_info+0x1191/0x1320 br_mdb_dump+0x594/0xe40 rtnl_mdb_dump+0x1cf/0x5d0 Use hlist_del_init_rcu() to unlink the group while preserving ->next. br_multicast_del_pg() and the teardown walks run under br->multicast_lock. The GC worker must acquire the same lock ...
In the Linux kernel, the following vulnerability has been resolved: net: bridge: mcast: don't truncate the port group walk on teardown __br_multicast_disable_port_ctx() and br_multicast_del_port() walk port->mglist with hlist_for_each_entry_safe(). However, br_multicast_find_del_pg() can also delete other entries from the same list through br_multicast_fwd_src_remove() or __fwd_del_star_excl(). If such an entry is the iterator's saved next node, hlist_del_init() clears its ->next and terminates the walk early. The reproducer triggers this in both teardown walks, leaving port groups in the bridge mdb with a dangling ->key.port after del_nbp() frees the port: BUG: KASAN: slab-use-after-free in __mdb_fill_info+0x1191/0x1320 __mdb_fill_info+0x1191/0x1320 br_mdb_dump+0x594/0xe40 rtnl_mdb_dump+0x1cf/0x5d0 Use hlist_del_init_rcu() to unlink the group while preserving ->next. br_multicast_del_pg() and the teardown walks run under br->multicast_lock. The GC worker must acquire t
net: bridge: mcast: don't truncate the port group walk on teardown
In the Linux kernel, the following vulnerability has been resolved: n ...
In the Linux kernel, the following vulnerability has been resolved: net: bridge: mcast: don't truncate the port group walk on teardown __br_multicast_disable_port_ctx() and br_multicast_del_port() walk port->mglist with hlist_for_each_entry_safe(). However, br_multicast_find_del_pg() can also delete other entries from the same list through br_multicast_fwd_src_remove() or __fwd_del_star_excl(). If such an entry is the iterator's saved next node, hlist_del_init() clears its ->next and terminates the walk early. The reproducer triggers this in both teardown walks, leaving port groups in the bridge mdb with a dangling ->key.port after del_nbp() frees the port: BUG: KASAN: slab-use-after-free in __mdb_fill_info+0x1191/0x1320 __mdb_fill_info+0x1191/0x1320 br_mdb_dump+0x594/0xe40 rtnl_mdb_dump+0x1cf/0x5d0 Use hlist_del_init_rcu() to unlink the group while preserving ->next. br_multicast_del_pg() and the teardown walks run under br->multicast_lock. The GC worker must acquir...
EPSS
5.5 Medium
CVSS3