- 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@
diff --git a/mac.c b/mac.c
new file mode 100644
index 0000000..3ff107c
--- /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);
+}