Stephen Smalley
2018-Sep-25 18:44 UTC
[Ocfs2-devel] Leaking path or inconsistency LSM checking observed in fs/net
On 09/25/2018 01:27 PM, Tong Zhang wrote:> Kernel Version: 4.18.5 > > Problem Description: > > We found several leaking path or inconsistency LSM design issue in fs/net. > > Currently we can only observe sock creation from kernel and all bind/listen/connect are not sent to LSM. > So, we think that those net/socket related stuff should all go through LSM check and being audited > even it is not a user thread or process. > > > Here?s an example where we have a check: > in fs/ocfs2/cluster/tcp.c:2035 o2net_open_listening_sock() a sock is created using sock_create(), > where a LSM check security_socket_create is called(net/socket.c:1242) > > > And where we don?t have a check > > fs/ocfs2/cluster/tcp.c:2052 bind > fs/ocfs2/cluster/tcp.c:2059 listen > > fs/dlm/lowcomms.c:1264 bind > fs/dlm/lowcomms.c:1278 listen > fs/dlm/lowcomms.c:1354 listen > > several places that use kernel_bind/kernel_listen/kernel_connect > > net/socket.c:3231 kernel_bind > net/socket.c:3237 kernel_listen > net/socket.c:3286 kernel_connectThat's intentional. LSM isn't trying to mediate kernel-internal operations, and we do not want to apply permission checks against the credentials of the current userspace process for such operations. ocfs2 should likely be using sock_create_kern.