FreeBSD change for openssh

Mike Karels karels at
Tue Nov 16 03:44:06 AEDT 2021

I've been working on cleanup of remnants of Internet Class A/B/C in
FreeBSD, and came across a piece of code in sshconnect.c that I'd
like to change.  The current code checks for loopback addresses by
picking apart the address as Class A (24 bit shift).  FreeBSD has a
newer IN_LOOPBACK() macro that determines whether an address is in the
loopback range, and I'd like to use that.  As not all systems provide
such a macro, I'd propose a default version that is essentially the
current FreeBSD version.  Part of the reason for using the system macro
is that there is a proposed change to the reserved space for loopback
heading toward the IETF, reserving rather than /8.

The following is a proposed change to sshconnect.c.

diff --git a/crypto/openssh/sshconnect.c b/crypto/openssh/sshconnect.c
index 8f7541942ac1..74636005eb7b 100644
--- a/crypto/openssh/sshconnect.c
+++ b/crypto/openssh/sshconnect.c
@@ -592,13 +592,20 @@ confirm(const char *prompt, const char *fingerprint)
+ * <netinet/in.h> may provide an IN_LOOPBACK() macro; use it if provided.
+ */
+#ifndef IN_LOOPBACK
+#define IN_LOOPBACK(i)		(((i) & 0xff000000) == 0x7f000000)
 static int
 sockaddr_is_local(struct sockaddr *hostaddr)
 	switch (hostaddr->sa_family) {
 	case AF_INET:
-		return (ntohl(((struct sockaddr_in *)hostaddr)->
-		    sin_addr.s_addr) >> 24) == IN_LOOPBACKNET;
+		return (IN_LOOPBACK(ntohl(((struct sockaddr_in *)hostaddr)->
+		    sin_addr.s_addr)));
 	case AF_INET6:
 		    &(((struct sockaddr_in6 *)hostaddr)->sin6_addr));

Comments or suggestions?


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