On Mon, Jan 24, 2022 at 3:02 AM Konstantin Meskhidze
<konstantin.meskhidze@xxxxxxxxxx> wrote:
>
> Support of socket_bind() and socket_connect() hooks.
> Current prototype can restrict binding and connecting of TCP
> types of sockets. Its just basic idea how Landlock could support
> network confinement.
>
> Changes:
> 1. Access masks array refactored into 1D one and changed
> to 32 bits. Filesystem masks occupy 16 lower bits and network
> masks reside in 16 upper bits.
> 2. Refactor API functions in ruleset.c:
> 1. Add void *object argument.
> 2. Add u16 rule_type argument.
> 3. Use two rb_trees in ruleset structure:
> 1. root_inode - for filesystem objects
> 2. root_net_port - for network port objects
>
> Signed-off-by: Konstantin Meskhidze <konstantin.meskhidze@xxxxxxxxxx>
> +static int hook_socket_connect(struct socket *sock, struct sockaddr *address, int addrlen)
> +{
> + short socket_type;
> + struct sockaddr_in *sockaddr;
> + u16 port;
> + const struct landlock_ruleset *const dom = landlock_get_current_domain();
> +
> + /* Check if the hook is AF_INET* socket's action */
> + if ((address->sa_family != AF_INET) && (address->sa_family != AF_INET6))
> + return 0;
Should this be a check on the socket family (sock->ops->family)
instead of the address family?
It is valid to pass an address with AF_UNSPEC to a PF_INET(6) socket.
And there are legitimate reasons to want to deny this. Such as passing
a connection to a unprivileged process and disallow it from disconnect
and opening a different new connection.
> +
> + socket_type = sock->type;
> + /* Check if it's a TCP socket */
> + if (socket_type != SOCK_STREAM)
> + return 0;
> +
> + if (!dom)
> + return 0;
> +
> + /* Get port value in host byte order */
> + sockaddr = (struct sockaddr_in *)address;
> + port = ntohs(sockaddr->sin_port);
> +
> + return check_socket_access(dom, port, LANDLOCK_ACCESS_NET_CONNECT_TCP);
> +}
