- markus@cvs.openbsd.org 2001/02/11 12:59:25

     [Makefile.in sshd.8 sshconnect2.c readconf.h readconf.c packet.c
      sshd.c ssh.c ssh.1 servconf.h servconf.c myproposal.h kex.h kex.c]
     1) clean up the MAC support for SSH-2
     2) allow you to specify the MAC with 'ssh -m'
     3) or the 'MACs' keyword in ssh(d)_config
     4) add hmac-{md5,sha1}-96
             ok stevesk@, provos@

1 files changed, 114 insertions, 0 deletions

diff --git a/mac.c b/mac.c
new file mode 100644
index 000000000..3ff107c8a
--- /dev/null
+++ b/mac.c
@@ -0,0 +1,114 @@
+/*
+ * Copyright (c) 2001 Markus Friedl.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "includes.h"
+RCSID("$OpenBSD: mac.c,v 1.1 2001/02/11 12:59:24 markus Exp $");
+
+#include <openssl/hmac.h>
+
+#include "xmalloc.h"
+#include "getput.h"
+#include "log.h"
+#include "cipher.h"
+#include "kex.h"
+#include "mac.h"
+
+struct {
+	char		*name;
+	EVP_MD *	(*mdfunc)(void);
+	int		truncatebits;	/* truncate digest if != 0 */
+} macs[] = {
+	{ "hmac-sha1",			EVP_sha1, 0, },
+	{ "hmac-sha1-96",		EVP_sha1, 96 },
+	{ "hmac-md5",			EVP_md5, 0 },
+	{ "hmac-md5-96",		EVP_md5, 96 },
+	{ "hmac-ripemd160",		EVP_ripemd160, 0 },
+	{ "hmac-ripemd160@openssh.com",	EVP_ripemd160, 0 },
+        { NULL,				NULL, 0 }
+};
+
+int
+mac_init(Mac *mac, char *name)
+{
+	int i;
+	for (i = 0; macs[i].name; i++) {
+		if (strcmp(name, macs[i].name) == 0) {
+			if (mac != NULL) {
+				mac->md = (*macs[i].mdfunc)();
+				mac->key_len = mac->mac_len = mac->md->md_size;
+				if (macs[i].truncatebits != 0)
+					mac->mac_len = macs[i].truncatebits/8;
+			}
+			debug2("mac_init: found %s", name);
+			return (0);
+		}
+	}
+	debug2("mac_init: unknown %s", name);
+	return (-1);
+}
+
+u_char *
+mac_compute(Mac *mac, u_int32_t seqno, u_char *data, int datalen)
+{
+	HMAC_CTX c;
+	static u_char m[EVP_MAX_MD_SIZE];
+	u_char b[4];
+
+	if (mac->key == NULL)
+		fatal("mac_compute: no key");
+	if (mac->mac_len > sizeof(m))
+		fatal("mac_compute: mac too long");
+	HMAC_Init(&c, mac->key, mac->key_len, mac->md);
+	PUT_32BIT(b, seqno);
+	HMAC_Update(&c, b, sizeof(b));
+	HMAC_Update(&c, data, datalen);
+	HMAC_Final(&c, m, NULL);
+	HMAC_cleanup(&c);
+	return (m);
+}
+
+/* XXX copied from ciphers_valid */
+#define	MAC_SEP	","
+int
+mac_valid(const char *names)
+{
+	char *maclist, *cp, *p;
+
+	if (names == NULL || strcmp(names, "") == 0)
+		return (0);
+	maclist = cp = xstrdup(names);
+	for ((p = strsep(&cp, MAC_SEP)); p && *p != '\0';
+	     (p = strsep(&cp, MAC_SEP))) {
+		if (mac_init(NULL, p) < 0) {
+			debug("bad mac %s [%s]", p, names);
+			xfree(maclist);
+			return (0);
+		} else {
+			debug3("mac ok: %s [%s]", p, names);
+		}
+	}
+	debug3("macs ok: [%s]", names);
+	xfree(maclist);
+	return (1);
+}