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authorMaciej Żenczykowski <maze@google.com>2019-11-25 15:37:04 -0800
committerDavid S. Miller <davem@davemloft.net>2019-11-26 13:20:46 -0800
commit82f31ebf61bed3077c9935308e0a4b6c44842c5a (patch)
tree0db99fcf06cb9dd3f5333406547d0ed0680cea52 /security/selinux
parente94a5d1681fcf6d857503a53febb4a54cee7e1d3 (diff)
downloadlinux-82f31ebf61bed3077c9935308e0a4b6c44842c5a.tar.gz
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>
Diffstat (limited to 'security/selinux')
-rw-r--r--security/selinux/hooks.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 9625b99e677f..753b327f4806 100644
--- 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)