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eb25e202b3
Add an LSM hook security_unix_find. This hook is called to check the path of a named UNIX socket before a connection is initiated. The peer socket may be inspected as well. Why existing hooks are unsuitable: Existing socket hooks, security_unix_stream_connect(), security_unix_may_send(), and security_socket_connect() don't provide TOCTOU-free / namespace independent access to the paths of sockets. (1) We cannot resolve the path from the struct sockaddr in existing hooks. This requires another path lookup. A change in the path between the two lookups will cause a TOCTOU bug. (2) We cannot use the struct path from the listening socket, because it may be bound to a path in a different namespace than the caller, resulting in a path that cannot be referenced at policy creation time. Consumers of the hook wishing to reference @other are responsible for acquiring the unix_state_lock and checking for the SOCK_DEAD flag therein, ensuring the socket hasn't died since lookup. Cc: Günther Noack <gnoack3000@gmail.com> Cc: Tingmao Wang <m@maowtm.org> Cc: Mickaël Salaün <mic@digikod.net> Cc: Paul Moore <paul@paul-moore.com> Signed-off-by: Justin Suess <utilityemal77@gmail.com> Signed-off-by: Günther Noack <gnoack3000@gmail.com> Reviewed-by: Georgia Garcia <georgia.garcia@canonical.com> Acked-by: Paul Moore <paul@paul-moore.com> Link: https://lore.kernel.org/r/20260327164838.38231-2-gnoack3000@gmail.com Signed-off-by: Mickaël Salaün <mic@digikod.net>