openssh/openssh-7.0p1-show-more-fingerprints.patch

From e1d58c44bd911e5ee4dddb6205e16eb9a03cc736 Mon Sep 17 00:00:00 2001
From: Jakub Jelen <jjelen@redhat.com>
Date: Fri, 7 Aug 2015 10:18:54 +0200
Subject: [PATCH] Possibility tu specify more fingerprint algorithms on client
 side for smother transition

---
 clientloop.c  |  8 ++++----
 readconf.c    | 43 +++++++++++++++++++++++++++++--------------
 readconf.h    |  4 +++-
 ssh_config.5  |  4 ++--
 sshconnect.c  | 48 +++++++++++++++++++++++++++---------------------
 sshconnect2.c |  6 +++---
 6 files changed, 68 insertions(+), 45 deletions(-)

diff --git a/clientloop.c b/clientloop.c
index 87ceb3d..4553114 100644
--- a/clientloop.c
+++ b/clientloop.c
@@ -2194,7 +2194,7 @@ update_known_hosts(struct hostkeys_update_ctx *ctx)
 		if (ctx->keys_seen[i] != 2)
 			continue;
 		if ((fp = sshkey_fingerprint(ctx->keys[i],
-		    options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL)
+		    options.fingerprint_hash[0], SSH_FP_DEFAULT)) == NULL)
 			fatal("%s: sshkey_fingerprint failed", __func__);
 		do_log2(loglevel, "Learned new hostkey: %s %s",
 		    sshkey_type(ctx->keys[i]), fp);
@@ -2202,7 +2202,7 @@ update_known_hosts(struct hostkeys_update_ctx *ctx)
 	}
 	for (i = 0; i < ctx->nold; i++) {
 		if ((fp = sshkey_fingerprint(ctx->old_keys[i],
-		    options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL)
+		    options.fingerprint_hash[0], SSH_FP_DEFAULT)) == NULL)
 			fatal("%s: sshkey_fingerprint failed", __func__);
 		do_log2(loglevel, "Deprecating obsolete hostkey: %s %s",
 		    sshkey_type(ctx->old_keys[i]), fp);
@@ -2245,7 +2245,7 @@ update_known_hosts(struct hostkeys_update_ctx *ctx)
 	    (r = hostfile_replace_entries(options.user_hostfiles[0],
 	    ctx->host_str, ctx->ip_str, ctx->keys, ctx->nkeys,
 	    options.hash_known_hosts, 0,
-	    options.fingerprint_hash)) != 0)
+	    options.fingerprint_hash[0])) != 0)
 		error("%s: hostfile_replace_entries failed: %s",
 		    __func__, ssh_err(r));
 }
@@ -2358,7 +2358,7 @@ client_input_hostkeys(void)
 			error("%s: parse key: %s", __func__, ssh_err(r));
 			goto out;
 		}
-		fp = sshkey_fingerprint(key, options.fingerprint_hash,
+		fp = sshkey_fingerprint(key, options.fingerprint_hash[0],
 		    SSH_FP_DEFAULT);
 		debug3("%s: received %s key %s", __func__,
 		    sshkey_type(key), fp);
diff --git a/readconf.c b/readconf.c
index 1d03bdf..6af4c62 100644
--- a/readconf.c
+++ b/readconf.c
@@ -1471,16 +1471,18 @@ parse_keytypes:
 		goto parse_string;
 
 	case oFingerprintHash:
-		intptr = &options->fingerprint_hash;
-		arg = strdelim(&s);
-		if (!arg || *arg == '\0')
-			fatal("%.200s line %d: Missing argument.",
-			    filename, linenum);
-		if ((value = ssh_digest_alg_by_name(arg)) == -1)
-			fatal("%.200s line %d: Invalid hash algorithm \"%s\".",
-			    filename, linenum, arg);
-		if (*activep && *intptr == -1)
-			*intptr = value;
+		if (*activep && options->num_fingerprint_hash == 0)
+			while ((arg = strdelim(&s)) != NULL && *arg != '\0') {
+				value = ssh_digest_alg_by_name(arg);
+				if (value == -1)
+					fatal("%s line %d: unknown fingerprints algorithm specs: %s.",
+						filename, linenum, arg);
+				if (options->num_fingerprint_hash >= SSH_DIGEST_MAX)
+					fatal("%s line %d: too many fingerprints algorithm specs.",
+						filename, linenum);
+				options->fingerprint_hash[
+					options->num_fingerprint_hash++] = value;
+			}
 		break;
 
 	case oUpdateHostkeys:
@@ -1673,7 +1675,7 @@ initialize_options(Options * options)
 	options->canonicalize_fallback_local = -1;
 	options->canonicalize_hostname = -1;
 	options->revoked_host_keys = NULL;
-	options->fingerprint_hash = -1;
+	options->num_fingerprint_hash = 0;
 	options->update_hostkeys = -1;
 	options->hostbased_key_types = NULL;
 	options->pubkey_key_types = NULL;
@@ -1851,8 +1853,10 @@ fill_default_options(Options * options)
 		options->canonicalize_fallback_local = 1;
 	if (options->canonicalize_hostname == -1)
 		options->canonicalize_hostname = SSH_CANONICALISE_NO;
-	if (options->fingerprint_hash == -1)
-		options->fingerprint_hash = SSH_FP_HASH_DEFAULT;
+	if (options->num_fingerprint_hash == 0) {
+		options->fingerprint_hash[options->num_fingerprint_hash++] = SSH_DIGEST_SHA256;
+		options->fingerprint_hash[options->num_fingerprint_hash++] = SSH_DIGEST_MD5;
+	}
 	if (options->update_hostkeys == -1)
 		options->update_hostkeys = 0;
 	if (kex_assemble_names(KEX_CLIENT_ENCRYPT, &options->ciphers) != 0 ||
@@ -2189,6 +2193,17 @@ dump_cfg_strarray(OpCodes code, u_int count, char **vals)
 }
 
 static void
+dump_cfg_fmtarray(OpCodes code, u_int count, int *vals)
+{
+	u_int i;
+
+	printf("%s", lookup_opcode_name(code));
+	for (i = 0; i < count; i++)
+		printf(" %s", fmt_intarg(code, vals[i]));
+	printf("\n");
+}
+
+static void
 dump_cfg_strarray_oneline(OpCodes code, u_int count, char **vals)
 {
 	u_int i;
@@ -2259,7 +2274,6 @@ dump_client_config(Options *o, const char *host)
 	dump_cfg_fmtint(oControlMaster, o->control_master);
 	dump_cfg_fmtint(oEnableSSHKeysign, o->enable_ssh_keysign);
 	dump_cfg_fmtint(oExitOnForwardFailure, o->exit_on_forward_failure);
-	dump_cfg_fmtint(oFingerprintHash, o->fingerprint_hash);
 	dump_cfg_fmtint(oForwardAgent, o->forward_agent);
 	dump_cfg_fmtint(oForwardX11, o->forward_x11);
 	dump_cfg_fmtint(oForwardX11Trusted, o->forward_x11_trusted);
@@ -2328,6 +2342,7 @@ dump_client_config(Options *o, const char *host)
 	dump_cfg_strarray_oneline(oGlobalKnownHostsFile, o->num_system_hostfiles, o->system_hostfiles);
 	dump_cfg_strarray_oneline(oUserKnownHostsFile, o->num_user_hostfiles, o->user_hostfiles);
 	dump_cfg_strarray(oSendEnv, o->num_send_env, o->send_env);
+	dump_cfg_fmtarray(oFingerprintHash, o->num_fingerprint_hash, o->fingerprint_hash);
 
 	/* Special cases */
 
diff --git a/readconf.h b/readconf.h
index bb2d552..d817f92 100644
--- a/readconf.h
+++ b/readconf.h
@@ -21,6 +21,7 @@
 #define MAX_SEND_ENV		256
 #define SSH_MAX_HOSTS_FILES	32
 #define MAX_CANON_DOMAINS	32
+#define MAX_SSH_DIGESTS	32
 #define PATH_MAX_SUN		(sizeof((struct sockaddr_un *)0)->sun_path)
 
 struct allowed_cname {
@@ -146,7 +147,8 @@ typedef struct {
 
 	char	*revoked_host_keys;
 
-	int	 fingerprint_hash;
+	int num_fingerprint_hash;
+	int 	fingerprint_hash[MAX_SSH_DIGESTS];
 
 	int	 update_hostkeys; /* one of SSH_UPDATE_HOSTKEYS_* */
 
diff --git a/ssh_config.5 b/ssh_config.5
index 5b0975f..e8e6458 100644
--- a/ssh_config.5
+++ b/ssh_config.5
@@ -647,13 +647,13 @@ or
 The default is
 .Dq no .
 .It Cm FingerprintHash
-Specifies the hash algorithm used when displaying key fingerprints.
+Specifies the hash algorithms used when displaying key fingerprints.
 Valid options are:
 .Dq md5
 and
 .Dq sha256 .
 The default is
-.Dq sha256 .
+.Dq "sha256 md5".
 .It Cm ForwardAgent
 Specifies whether the connection to the authentication agent (if any)
 will be forwarded to the remote machine.
diff --git a/sshconnect.c b/sshconnect.c
index f41960c..e12932f 100644
--- a/sshconnect.c
+++ b/sshconnect.c
@@ -920,9 +920,9 @@ check_host_key(char *hostname, struct sockaddr *hostaddr, u_short port,
 				    "of known hosts.", type, ip);
 		} else if (options.visual_host_key) {
 			fp = sshkey_fingerprint(host_key,
-			    options.fingerprint_hash, SSH_FP_DEFAULT);
+			    options.fingerprint_hash[0], SSH_FP_DEFAULT);
 			ra = sshkey_fingerprint(host_key,
-			    options.fingerprint_hash, SSH_FP_RANDOMART);
+			    options.fingerprint_hash[0], SSH_FP_RANDOMART);
 			if (fp == NULL || ra == NULL)
 				fatal("%s: sshkey_fingerprint fail", __func__);
 			logit("Host key fingerprint is %s\n%s\n", fp, ra);
@@ -964,12 +964,6 @@ check_host_key(char *hostname, struct sockaddr *hostaddr, u_short port,
 			else
 				snprintf(msg1, sizeof(msg1), ".");
 			/* The default */
-			fp = sshkey_fingerprint(host_key,
-			    options.fingerprint_hash, SSH_FP_DEFAULT);
-			ra = sshkey_fingerprint(host_key,
-			    options.fingerprint_hash, SSH_FP_RANDOMART);
-			if (fp == NULL || ra == NULL)
-				fatal("%s: sshkey_fingerprint fail", __func__);
 			msg2[0] = '\0';
 			if (options.verify_host_key_dns) {
 				if (matching_host_key_dns)
@@ -983,16 +977,28 @@ check_host_key(char *hostname, struct sockaddr *hostaddr, u_short port,
 			}
 			snprintf(msg, sizeof(msg),
 			    "The authenticity of host '%.200s (%s)' can't be "
-			    "established%s\n"
-			    "%s key fingerprint is %s.%s%s\n%s"
+			    "established%s\n", host, ip, msg1);
+			for (i = 0; i < options.num_fingerprint_hash; i++) {
+				fp = sshkey_fingerprint(host_key,
+				    options.fingerprint_hash[i], SSH_FP_DEFAULT);
+				ra = sshkey_fingerprint(host_key,
+				    options.fingerprint_hash[i], SSH_FP_RANDOMART);
+				if (fp == NULL || ra == NULL)
+					fatal("%s: sshkey_fingerprint fail", __func__);
+				len = strlen(msg);
+				snprintf(msg+len, sizeof(msg)-len,
+				    "%s key fingerprint is %s.%s%s\n%s",
+				    type, fp,
+				    options.visual_host_key ? "\n" : "",
+				    options.visual_host_key ? ra : "",
+				    msg2);
+				free(ra);
+				free(fp);
+			}
+			len = strlen(msg);
+			snprintf(msg+len, sizeof(msg)-len,
 			    "Are you sure you want to continue connecting "
-			    "(yes/no)? ",
-			    host, ip, msg1, type, fp,
-			    options.visual_host_key ? "\n" : "",
-			    options.visual_host_key ? ra : "",
-			    msg2);
-			free(ra);
-			free(fp);
+			    "(yes/no)? ");
 			if (!confirm(msg))
 				goto fail;
 			hostkey_trusted = 1; /* user explicitly confirmed */
@@ -1241,7 +1247,7 @@ verify_host_key(char *host, struct sockaddr *hostaddr, Key *host_key)
 	struct sshkey *plain = NULL;
 
 	if ((fp = sshkey_fingerprint(host_key,
-	    options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL) {
+	    options.fingerprint_hash[0], SSH_FP_DEFAULT)) == NULL) {
 		error("%s: fingerprint host key: %s", __func__, ssh_err(r));
 		r = -1;
 		goto out;
@@ -1405,9 +1411,9 @@ show_other_keys(struct hostkeys *hostkeys, Key *key)
 		if (!lookup_key_in_hostkeys_by_type(hostkeys, type[i], &found))
 			continue;
 		fp = sshkey_fingerprint(found->key,
-		    options.fingerprint_hash, SSH_FP_DEFAULT);
+		    options.fingerprint_hash[0], SSH_FP_DEFAULT);
 		ra = sshkey_fingerprint(found->key,
-		    options.fingerprint_hash, SSH_FP_RANDOMART);
+		    options.fingerprint_hash[0], SSH_FP_RANDOMART);
 		if (fp == NULL || ra == NULL)
 			fatal("%s: sshkey_fingerprint fail", __func__);
 		logit("WARNING: %s key found for host %s\n"
@@ -1430,7 +1436,7 @@ warn_changed_key(Key *host_key)
 {
 	char *fp;
 
-	fp = sshkey_fingerprint(host_key, options.fingerprint_hash,
+	fp = sshkey_fingerprint(host_key, options.fingerprint_hash[0],
 	    SSH_FP_DEFAULT);
 	if (fp == NULL)
 		fatal("%s: sshkey_fingerprint fail", __func__);
diff --git a/sshconnect2.c b/sshconnect2.c
index 7751031..82ed92e 100644
--- a/sshconnect2.c
+++ b/sshconnect2.c
@@ -589,7 +589,7 @@ input_userauth_pk_ok(int type, u_int32_t seq, void *ctxt)
 		    key->type, pktype);
 		goto done;
 	}
-	if ((fp = sshkey_fingerprint(key, options.fingerprint_hash,
+	if ((fp = sshkey_fingerprint(key, options.fingerprint_hash[0],
 	    SSH_FP_DEFAULT)) == NULL)
 		goto done;
 	debug2("input_userauth_pk_ok: fp %s", fp);
@@ -1009,7 +1009,7 @@ sign_and_send_pubkey(Authctxt *authctxt, Identity *id)
 	int have_sig = 1;
 	char *fp;
 
-	if ((fp = sshkey_fingerprint(id->key, options.fingerprint_hash,
+	if ((fp = sshkey_fingerprint(id->key, options.fingerprint_hash[0],
 	    SSH_FP_DEFAULT)) == NULL)
 		return 0;
 	debug3("sign_and_send_pubkey: %s %s", key_type(id->key), fp);
@@ -1635,7 +1635,7 @@ userauth_hostbased(Authctxt *authctxt)
 		goto out;
 	}
 
-	if ((fp = sshkey_fingerprint(private, options.fingerprint_hash,
+	if ((fp = sshkey_fingerprint(private, options.fingerprint_hash[0],
 	    SSH_FP_DEFAULT)) == NULL) {
 		error("%s: sshkey_fingerprint failed", __func__);
 		goto out;
diff --git a/ssh-keysign.c b/ssh-keysign.c
index 1dca3e2..23bff7d 100644
--- a/ssh-keysign.c
+++ b/ssh-keysign.c
@@ -275,7 +275,7 @@ main(int argc, char **argv)
 		}
 	}
 	if (!found) {
-		if ((fp = sshkey_fingerprint(key, options.fingerprint_hash,
+		if ((fp = sshkey_fingerprint(key, options.fingerprint_hash[0],
 		    SSH_FP_DEFAULT)) == NULL)
 			fatal("%s: sshkey_fingerprint failed", __func__);
 		fatal("no matching hostkey found for key %s %s",

-- 
2.1.0