net: port < inet_prot_sock(net) --> inet_port_requires_bind_service(net, port)

Note that the sysctl write accessor functions guarantee that:
  net->ipv4.sysctl_ip_prot_sock <= net->ipv4.ip_local_ports.range[0]
invariant is maintained, and as such the max() in selinux hooks is actually spurious.

ie. even though
  if (snum < max(inet_prot_sock(sock_net(sk)), low) || snum > high) {
per logic is the same as
  if ((snum < inet_prot_sock(sock_net(sk)) && snum < low) || snum > high) {
it is actually functionally equivalent to:
  if (snum < low || snum > high) {
which is equivalent to:
  if (snum < inet_prot_sock(sock_net(sk)) || snum < low || snum > high) {
even though the first clause is spurious.

But we want to hold on to it in case we ever want to change what what
inet_port_requires_bind_service() means (for example by changing
it from a, by default, [0..1024) range to some sort of set).

Test: builds, git 'grep inet_prot_sock' finds no other references
Cc: Eric Dumazet <edumazet@google.com>
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/ip.h b/include/net/ip.h
index cebf3e10def1afef65dcb89f3beb64550ca6da35..5a61bd948b189454578a45537e9f0103fc8ef77b 100644 (file)
--- a/include/net/ip.h
+++ b/include/net/ip.h
@@ -351,9 +351,9 @@ static inline bool sysctl_dev_name_is_allowed(const char *name)
        return strcmp(name, "default") != 0  && strcmp(name, "all") != 0;
 }
 
-static inline int inet_prot_sock(struct net *net)
+static inline bool inet_port_requires_bind_service(struct net *net, unsigned short port)
 {
-       return net->ipv4.sysctl_ip_prot_sock;
+       return port < net->ipv4.sysctl_ip_prot_sock;
 }
 
 #else
@@ -362,9 +362,9 @@ static inline bool inet_is_local_reserved_port(struct net *net, int port)
        return false;
 }
 
-static inline int inet_prot_sock(struct net *net)
+static inline bool inet_port_requires_bind_service(struct net *net, unsigned short port)
 {
-       return PROT_SOCK;
+       return port < PROT_SOCK;
 }
 #endif
 

diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
index 53de8e00990e276448df1c60e47620be3b58f517..2fe295432c2457518aa518fd4e3f7ba6824d12ba 100644 (file)
--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c
@@ -495,7 +495,7 @@ int __inet_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len,
 
        snum = ntohs(addr->sin_port);
        err = -EACCES;
-       if (snum && snum < inet_prot_sock(net) &&
+       if (snum && inet_port_requires_bind_service(net, snum) &&
            !ns_capable(net->user_ns, CAP_NET_BIND_SERVICE))
                goto out;
 

diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c
index ef37e0574f544c59810d3ea58a877b8c43b0ccbd..60e2ff91a5b368e1de2fd99ba5486ead2d7b62a6 100644 (file)
--- a/net/ipv6/af_inet6.c
+++ b/net/ipv6/af_inet6.c
@@ -292,7 +292,7 @@ static int __inet6_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len,
                return -EINVAL;
 
        snum = ntohs(addr->sin6_port);
-       if (snum && snum < inet_prot_sock(net) &&
+       if (snum && inet_port_requires_bind_service(net, snum) &&
            !ns_capable(net->user_ns, CAP_NET_BIND_SERVICE))
                return -EACCES;
 

diff --git a/net/netfilter/ipvs/ip_vs_ctl.c b/net/netfilter/ipvs/ip_vs_ctl.c
index 3be7398901e09a74ebc5ceb5c416a96ca5ff2a69..8d14a1acbc37057282a36f7ea33004eb42781e29 100644 (file)
--- a/net/netfilter/ipvs/ip_vs_ctl.c
+++ b/net/netfilter/ipvs/ip_vs_ctl.c
@@ -423,7 +423,7 @@ ip_vs_service_find(struct netns_ipvs *ipvs, int af, __u32 fwmark, __u16 protocol
 
        if (!svc && protocol == IPPROTO_TCP &&
            atomic_read(&ipvs->ftpsvc_counter) &&
-           (vport == FTPDATA || ntohs(vport) >= inet_prot_sock(ipvs->net))) {
+           (vport == FTPDATA || !inet_port_requires_bind_service(ipvs->net, ntohs(vport)))) {
                /*
                 * Check if ftp service entry exists, the packet
                 * might belong to FTP data connections.

diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index e4c398db07a01412b5197d633ed8f5012fc2ddee..0b485952a71c15f9503437e5d0b0769fb4053b2d 100644 (file)
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -384,7 +384,7 @@ static int sctp_do_bind(struct sock *sk, union sctp_addr *addr, int len)
                }
        }
 
-       if (snum && snum < inet_prot_sock(net) &&
+       if (snum && inet_port_requires_bind_service(net, snum) &&
            !ns_capable(net->user_ns, CAP_NET_BIND_SERVICE))
                return -EACCES;
 
@@ -1061,7 +1061,7 @@ static int sctp_connect_new_asoc(struct sctp_endpoint *ep,
                if (sctp_autobind(sk))
                        return -EAGAIN;
        } else {
-               if (ep->base.bind_addr.port < inet_prot_sock(net) &&
+               if (inet_port_requires_bind_service(net, ep->base.bind_addr.port) &&
                    !ns_capable(net->user_ns, CAP_NET_BIND_SERVICE))
                        return -EACCES;
        }

diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 9625b99e677fd33cf4abc1ebcc48fb3b79fb44d8..753b327f48067c3be23f8b5661c30b07c99e09a3 100644 (file)
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -4623,8 +4623,8 @@ 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(inet_prot_sock(sock_net(sk)), low) ||
-                           snum > high) {
+                       if (inet_port_requires_bind_service(sock_net(sk), snum) ||
+                           snum < low || snum > high) {
                                err = sel_netport_sid(sk->sk_protocol,
                                                      snum, &sid);
                                if (err)