ssh: canonicize the host name before looking it up in the host file

Re-apply r99054 by des in 2002.  This was accidentally dropped
by the update to OpenSSH 6.5p1 (r261320).

This change is actually taken from r387082 of
ports/security/openssh-portable/files/patch-ssh.c

PR:		198043
Differential Revision:	https://reviews.freebsd.org/D3103
Reviewed by:	des
Approved by:	kib (mentor)
MFC after:	3 days
Relnotes:	yes
Sponsored by:	Dell Inc.

1 files changed, 17 insertions, 0 deletions

diff --git a/crypto/openssh/ssh.c b/crypto/openssh/ssh.c
index eb69b72b9fa1..1c0784a9f2c2 100644
--- a/crypto/openssh/ssh.c
+++ b/crypto/openssh/ssh.c
@@ -1001,6 +1001,23 @@ main(int ac, char **av)
 	shorthost[strcspn(thishost, ".")] = '\0';
 	snprintf(portstr, sizeof(portstr), "%d", options.port);
 
+	/* Find canonic host name. */
+	if (strchr(host, '.') == 0) {
+		struct addrinfo hints;
+		struct addrinfo *ai = NULL;
+		int errgai;
+		memset(&hints, 0, sizeof(hints));
+		hints.ai_family = options.address_family;
+		hints.ai_flags = AI_CANONNAME;
+		hints.ai_socktype = SOCK_STREAM;
+		errgai = getaddrinfo(host, NULL, &hints, &ai);
+		if (errgai == 0) {
+			if (ai->ai_canonname != NULL)
+				host = xstrdup(ai->ai_canonname);
+			freeaddrinfo(ai);
+		}
+	}
+
 	if (options.local_command != NULL) {
 		debug3("expanding LocalCommand: %s", options.local_command);
 		cp = options.local_command;