8.8 HIGH
- CVSS version (CVSS): 3.1
- Attack Vector (AV): Local (L)
- Attack Complexity (AC): Low (L)
- Privileges Required (PR): Low (L)
- User Interaction (UI): None (N)
- Scope (S): Changed (C)
- Confidentiality (C): High (H)
- Integrity (I): High (H)
- Availability (A): High (H)
- Modified Attack Vector (MAV): Local (L)
- Modified Attack Complexity (MAC): Low (L)
- Modified Privileges Required (MPR): Low (L)
- Modified User Interaction (MUI): None (N)
- Modified Confidentiality (MC): High (H)
- Modified Scope (MS): Changed (C)
- Modified Integrity (MI): High (H)
- Modified Availability (MA): High (H)
Activity log
- Created & dismissed (max. allowed matches exceeded) suggestion
vsock/vmci: fix UAF when peer resets connection during handshake
In the Linux kernel, the following vulnerability has been resolved: vsock/vmci: fix UAF when peer resets connection during handshake vmci_transport_recv_connecting_server() returned err = 0 for a peer RST in its default switch arm: err = pkt->type == VMCI_TRANSPORT_PACKET_TYPE_RST ? 0 : -EINVAL; That made vmci_transport_recv_listen() skip vsock_remove_pending(), leaving the pending socket on the listener's pending_links with sk_state = TCP_CLOSE while destroy: still dropped the explicit reference taken before schedule_delayed_work(). One second later vsock_pending_work() observed is_pending=true and performed full cleanup: vsock_remove_pending() then the two trailing sock_put(sk) calls -- the first reached refcount 0 and __sk_freed the socket, and the second wrote into the freed object: BUG: KASAN: slab-use-after-free in refcount_warn_saturate Write of size 4 at addr ffff88800b1cac80 by task kworker Workqueue: events vsock_pending_work Treat peer RST like any other unexpected packet type (err = -EINVAL). All destroy: arms now return err < 0, so vmci_transport_recv_listen() removes pending from pending_links synchronously and vsock_pending_work() takes the is_pending=false / !rejected branch, dropping only its own work reference. This also closes the multi-packet race Sashiko reported on v2: pending is removed from the list before any subsequent packet can find it. The pre-existing sk_acceptq_removed() gap on the err < 0 path of vmci_transport_recv_listen() that Sashiko also noted is not introduced or changed by this patch. Tested on lts-6.12.79 with KASAN: 52/100 unpatched -> 0/100 patched.
References
Affected products
- <1dd531e28f61edd286edc486ab068f135b5ae1eb
- =<5.10.*
- =<6.18.*
- ==3.9
- =<7.0.*
- =<6.12.*
- <9fe74e42914c851d68069713b7b917a9c33faf26
- <cc27e989a5dfdfcfc1cca7c3be27a0c7532b46cb
- <ecda37f8faab3220da199335e42564cb7a9ad145
- <440447699c681e26ed58e9c309cad718270a18b4
- =<*
- <99e22ddf4edb63dc8382bc028af928056d3450cf
- =<6.1.*
- <47e63077605c6c2aa45b3df9847a8cdc1f1f6ef9
- =<5.15.*
- <1e19f08552b90070ed18bafb1763c78297823af6
- =<6.6.*
- <3.9