Affected: Alpaquita:23: linux-lts, Alpaquita:25: linux-lts, Alpaquita:stream: linux-lts

In the Linux kernel, the following vulnerability has been resolved:

ipmi: Fix user refcount underflow in event delivery

ipmi_alloc_recv_msg(user) takes the temporary user reference owned by the receive message, and ipmi_free_recv_msg() drops it again. If event delivery fails after allocating receive messages for earlier users, handle_read_event_rsp() rolls those messages back with ipmi_free_recv_msg().

That rollback path still drops user->refcount explicitly after freeing each message. The extra put can free a user that remains linked on intf->users, so later event delivery may dereference a freed user or trip refcount_t's addition-on-zero warning when ipmi_alloc_recv_msg() tries to acquire another reference.

Remove the stale explicit put and the now-dead user assignment. Keep the list_del() and ipmi_free_recv_msg() calls; they are the required rollback operations.

In the Linux kernel, the following vulnerability has been resolved:

ipmi: Fix user refcount underflow in event delivery

ipmi_alloc_recv_msg(user) takes the temporary user reference owned by the receive message, and ipmi_free_recv_msg() drops it again. If event delivery fails after allocating receive messages for earlier users, handle_read_event_rsp() rolls those messages back with ipmi_free_recv_msg().

That rollback path still drops user->refcount explicitly after freeing each message. The extra put can free a user that remains linked on intf->users, so later event delivery may dereference a freed user or trip refcount_t's addition-on-zero warning when ipmi_alloc_recv_msg() tries to acquire another reference.

Remove the stale explicit put and the now-dead user assignment. Keep the list_del() and ipmi_free_recv_msg() calls; they are the required rollback operations.

Affected: Ubuntu:16.04:LTS: linux-hwe-edge, Ubuntu:18.04:LTS: linux-aws-5.0, Ubuntu:18.04:LTS: linux-aws-5.3, Ubuntu:18.04:LTS: linux-azure, Ubuntu:18.04:LTS: linux-azure-5.3, Ubuntu:18.04:LTS: linux-azure-edge, Ubuntu:18.04:LTS: linux-gcp, Ubuntu:18.04:LTS: linux-gcp-5.3, Ubuntu:18.04:LTS: linux-gke-4.15, Ubuntu:18.04:LTS: linux-gke-5.4 and 154 more

In the Linux kernel, the following vulnerability has been resolved: ipmi: Fix user refcount underflow in event delivery ipmi_alloc_recv_msg(user) takes the temporary user reference owned by the receive message, and ipmi_free_recv_msg() drops it again. If event delivery fails after allocating receive messages for earlier users, handle_read_event_rsp() rolls those messages back with ipmi_free_recv_msg(). That rollback path still drops user->refcount explicitly after freeing each message. The extra put can free a user that remains linked on intf->users, so later event delivery may dereference a freed user or trip refcount_t's addition-on-zero warning when ipmi_alloc_recv_msg() tries to acquire another reference. Remove the stale explicit put and the now-dead user assignment. Keep the list_del() and ipmi_free_recv_msg() calls; they are the required rollback operations.

Ein Angreifer kann mehrere Schwachstellen in Linux Kernel ausnutzen, um root Rechte zu erlangen, um einen Denial of Service herbeizuführen oder einen nicht näher spezifizierten Angriff durchzuführen.