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

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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>
This commit is contained in:
Maciej Żenczykowski
2019-11-25 15:37:04 -08:00
committed by David S. Miller
parent e94a5d1681
commit 82f31ebf61
6 changed files with 11 additions and 11 deletions
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4
security/selinux/hooks.c
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@@ -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)