From 4548b683b78137f8eadeb312b94e20bb0d4a7141 Mon Sep 17 00:00:00 2001 From: Krister Johansen Date: Fri, 20 Jan 2017 17:49:11 -0800 Subject: Introduce a sysctl that modifies the value of PROT_SOCK. Add net.ipv4.ip_unprivileged_port_start, which is a per namespace sysctl that denotes the first unprivileged inet port in the namespace. To disable all privileged ports set this to zero. It also checks for overlap with the local port range. The privileged and local range may not overlap. The use case for this change is to allow containerized processes to bind to priviliged ports, but prevent them from ever being allowed to modify their container's network configuration. The latter is accomplished by ensuring that the network namespace is not a child of the user namespace. This modification was needed to allow the container manager to disable a namespace's priviliged port restrictions without exposing control of the network namespace to processes in the user namespace. Signed-off-by: Krister Johansen Signed-off-by: David S. Miller --- security/selinux/hooks.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'security') diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index c7c6619431d5..53cb6da5f1c6 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -4365,7 +4365,8 @@ static int selinux_socket_bind(struct socket *sock, struct sockaddr *address, in inet_get_local_port_range(sock_net(sk), &low, &high); - if (snum < max(PROT_SOCK, low) || snum > high) { + if (snum < max(inet_prot_sock(sock_net(sk)), low) || + snum > high) { err = sel_netport_sid(sk->sk_protocol, snum, &sid); if (err) -- cgit v1.2.3-70-g09d2