vishalmishra434 / rpms / openssh

Forked from rpms/openssh a month ago
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diff --git a/ChangeLog b/ChangeLog
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index 38de846..1603a07 100644
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--- a/ChangeLog
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+++ b/ChangeLog
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@@ -1,3 +1,14 @@
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+20140420
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+   - djm@cvs.openbsd.org 2014/04/01 03:34:10
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+     [sshconnect.c]
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+     When using VerifyHostKeyDNS with a DNSSEC resolver, down-convert any
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+     certificate keys to plain keys and attempt SSHFP resolution.
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+     
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+     Prevents a server from skipping SSHFP lookup and forcing a new-hostkey
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+     dialog by offering only certificate keys.
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+     
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+     Reported by mcv21 AT cam.ac.uk
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+
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 20140313
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  - (djm) Release OpenSSH 6.6
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diff --git a/sshconnect.c b/sshconnect.c
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index 394cca8..e636f33 100644
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--- a/sshconnect.c
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+++ b/sshconnect.c
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@@ -1219,30 +1219,40 @@ verify_host_key(char *host, struct sockaddr *hostaddr, Key *host_key)
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 {
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 	int flags = 0;
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 	char *fp;
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+	Key *plain = NULL;
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 	fp = key_selected_fingerprint(host_key, SSH_FP_HEX);
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 	debug("Server host key: %s %s%s", key_type(host_key),
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 	    key_fingerprint_prefix(), fp);
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 	free(fp);
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-	/* XXX certs are not yet supported for DNS */
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-	if (!key_is_cert(host_key) && options.verify_host_key_dns &&
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-	    verify_host_key_dns(host, hostaddr, host_key, &flags) == 0) {
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-		if (flags & DNS_VERIFY_FOUND) {
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-
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-			if (options.verify_host_key_dns == 1 &&
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-			    flags & DNS_VERIFY_MATCH &&
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-			    flags & DNS_VERIFY_SECURE)
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-				return 0;
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-
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-			if (flags & DNS_VERIFY_MATCH) {
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-				matching_host_key_dns = 1;
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-			} else {
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-				warn_changed_key(host_key);
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-				error("Update the SSHFP RR in DNS with the new "
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-				    "host key to get rid of this message.");
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+	if (options.verify_host_key_dns) {
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+		/*
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+		 * XXX certs are not yet supported for DNS, so downgrade
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+		 * them and try the plain key.
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+		 */
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+		plain = key_from_private(host_key);
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+		if (key_is_cert(plain))
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+			key_drop_cert(plain);
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+		if (verify_host_key_dns(host, hostaddr, plain, &flags) == 0) {
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+			if (flags & DNS_VERIFY_FOUND) {
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+				if (options.verify_host_key_dns == 1 &&
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+				    flags & DNS_VERIFY_MATCH &&
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+				    flags & DNS_VERIFY_SECURE) {
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+					key_free(plain);
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+					return 0;
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+				}
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+				if (flags & DNS_VERIFY_MATCH) {
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+					matching_host_key_dns = 1;
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+				} else {
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+					warn_changed_key(plain);
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+					error("Update the SSHFP RR in DNS "
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+					    "with the new host key to get rid "
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+					    "of this message.");
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+				}
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 			}
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 		}
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+		key_free(plain);
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 	}
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 	return check_host_key(host, hostaddr, options.port, host_key, RDRW,