external/openssh: update to 6.8p1.

In preparation for some updates to external/openssh to make it work with
BoringSSL, this change updates the code to a recent version. The current
version (5.9p1) is coming up on four years old now.

  * Confirmed that f5c67b478bef9992de9e9ec91ce10af4f6205e0d matches
    OpenSSH 5.9p1 exactly (save for the removal of the scard
    subdirectory).

  * Downloaded openssh-6.8p1.tar.gz (SHA256:
    3ff64ce73ee124480b5bf767b9830d7d3c03bbcb6abe716b78f0192c37ce160e)
    and verified with PGP signature. (I've verified Damien's key in
    person previously.)

  * Applied changes between f5c67b478bef9992de9e9ec91ce10af4f6205e0d and
    OpenSSH 5.9p1 to 6.8p1 and updated the build as best I can. The
    ugliest change is probably the duplication of umac.c to umac128.c
    because Android conditionally compiles that file twice. See the
    comment in those files.

Change-Id: I63cb07a8118afb5a377f116087a0882914cea486
diff --git a/mac.c b/mac.c
index 0ac9dd8..64c3aa1 100644
--- a/mac.c
+++ b/mac.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: mac.c,v 1.16 2011/08/02 01:22:11 djm Exp $ */
+/* $OpenBSD: mac.c,v 1.32 2015/01/15 18:32:54 naddy Exp $ */
 /*
  * Copyright (c) 2001 Markus Friedl.  All rights reserved.
  *
@@ -27,146 +27,204 @@
 
 #include <sys/types.h>
 
-#include <openssl/hmac.h>
-
-#include <stdarg.h>
 #include <string.h>
-#include <signal.h>
+#include <stdio.h>
 
-#include "xmalloc.h"
-#include "log.h"
-#include "cipher.h"
-#include "buffer.h"
-#include "key.h"
-#include "kex.h"
+#include "digest.h"
+#include "hmac.h"
+#include "umac.h"
 #include "mac.h"
 #include "misc.h"
+#include "ssherr.h"
+#include "sshbuf.h"
 
-#include "umac.h"
+#include "openbsd-compat/openssl-compat.h"
 
-#define SSH_EVP		1	/* OpenSSL EVP-based MAC */
+#define SSH_DIGEST	1	/* SSH_DIGEST_XXX */
 #define SSH_UMAC	2	/* UMAC (not integrated with OpenSSL) */
+#define SSH_UMAC128	3
 
-struct {
+struct macalg {
 	char		*name;
 	int		type;
-	const EVP_MD *	(*mdfunc)(void);
+	int		alg;
 	int		truncatebits;	/* truncate digest if != 0 */
 	int		key_len;	/* just for UMAC */
 	int		len;		/* just for UMAC */
-} macs[] = {
-	{ "hmac-sha1",			SSH_EVP, EVP_sha1, 0, -1, -1 },
-	{ "hmac-sha1-96",		SSH_EVP, EVP_sha1, 96, -1, -1 },
-#ifdef HAVE_EVP_SHA256
-	{ "hmac-sha2-256",		SSH_EVP, EVP_sha256, 0, -1, -1 },
-	{ "hmac-sha2-256-96",		SSH_EVP, EVP_sha256, 96, -1, -1 },
-	{ "hmac-sha2-512",		SSH_EVP, EVP_sha512, 0, -1, -1 },
-	{ "hmac-sha2-512-96",		SSH_EVP, EVP_sha512, 96, -1, -1 },
-#endif
-	{ "hmac-md5",			SSH_EVP, EVP_md5, 0, -1, -1 },
-	{ "hmac-md5-96",		SSH_EVP, EVP_md5, 96, -1, -1 },
-#ifdef HAVE_EVP_RIPEMD
-	{ "hmac-ripemd160",		SSH_EVP, EVP_ripemd160, 0, -1, -1 },
-	{ "hmac-ripemd160@openssh.com",	SSH_EVP, EVP_ripemd160, 0, -1, -1 },
-#endif
-	{ "umac-64@openssh.com",	SSH_UMAC, NULL, 0, 128, 64 },
-	{ NULL,				0, NULL, 0, -1, -1 }
+	int		etm;		/* Encrypt-then-MAC */
 };
 
-static void
-mac_setup_by_id(Mac *mac, int which)
+static const struct macalg macs[] = {
+	/* Encrypt-and-MAC (encrypt-and-authenticate) variants */
+	{ "hmac-sha1",				SSH_DIGEST, SSH_DIGEST_SHA1, 0, 0, 0, 0 },
+	{ "hmac-sha1-96",			SSH_DIGEST, SSH_DIGEST_SHA1, 96, 0, 0, 0 },
+#ifdef HAVE_EVP_SHA256
+	{ "hmac-sha2-256",			SSH_DIGEST, SSH_DIGEST_SHA256, 0, 0, 0, 0 },
+	{ "hmac-sha2-512",			SSH_DIGEST, SSH_DIGEST_SHA512, 0, 0, 0, 0 },
+#endif
+	{ "hmac-md5",				SSH_DIGEST, SSH_DIGEST_MD5, 0, 0, 0, 0 },
+	{ "hmac-md5-96",			SSH_DIGEST, SSH_DIGEST_MD5, 96, 0, 0, 0 },
+#if defined(HAVE_EVP_RIPEMD)
+	{ "hmac-ripemd160",			SSH_DIGEST, SSH_DIGEST_RIPEMD160, 0, 0, 0, 0 },
+	{ "hmac-ripemd160@openssh.com",		SSH_DIGEST, SSH_DIGEST_RIPEMD160, 0, 0, 0, 0 },
+#endif
+	{ "umac-64@openssh.com",		SSH_UMAC, 0, 0, 128, 64, 0 },
+	{ "umac-128@openssh.com",		SSH_UMAC128, 0, 0, 128, 128, 0 },
+
+	/* Encrypt-then-MAC variants */
+	{ "hmac-sha1-etm@openssh.com",		SSH_DIGEST, SSH_DIGEST_SHA1, 0, 0, 0, 1 },
+	{ "hmac-sha1-96-etm@openssh.com",	SSH_DIGEST, SSH_DIGEST_SHA1, 96, 0, 0, 1 },
+#ifdef HAVE_EVP_SHA256
+	{ "hmac-sha2-256-etm@openssh.com",	SSH_DIGEST, SSH_DIGEST_SHA256, 0, 0, 0, 1 },
+	{ "hmac-sha2-512-etm@openssh.com",	SSH_DIGEST, SSH_DIGEST_SHA512, 0, 0, 0, 1 },
+#endif
+	{ "hmac-md5-etm@openssh.com",		SSH_DIGEST, SSH_DIGEST_MD5, 0, 0, 0, 1 },
+	{ "hmac-md5-96-etm@openssh.com",	SSH_DIGEST, SSH_DIGEST_MD5, 96, 0, 0, 1 },
+	{ "hmac-ripemd160-etm@openssh.com",	SSH_DIGEST, SSH_DIGEST_RIPEMD160, 0, 0, 0, 1 },
+	{ "umac-64-etm@openssh.com",		SSH_UMAC, 0, 0, 128, 64, 1 },
+	{ "umac-128-etm@openssh.com",		SSH_UMAC128, 0, 0, 128, 128, 1 },
+
+	{ NULL,					0, 0, 0, 0, 0, 0 }
+};
+
+/* Returns a list of supported MACs separated by the specified char. */
+char *
+mac_alg_list(char sep)
 {
-	int evp_len;
-	mac->type = macs[which].type;
-	if (mac->type == SSH_EVP) {
-		mac->evp_md = (*macs[which].mdfunc)();
-		if ((evp_len = EVP_MD_size(mac->evp_md)) <= 0)
-			fatal("mac %s len %d", mac->name, evp_len);
-		mac->key_len = mac->mac_len = (u_int)evp_len;
+	char *ret = NULL, *tmp;
+	size_t nlen, rlen = 0;
+	const struct macalg *m;
+
+	for (m = macs; m->name != NULL; m++) {
+		if (ret != NULL)
+			ret[rlen++] = sep;
+		nlen = strlen(m->name);
+		if ((tmp = realloc(ret, rlen + nlen + 2)) == NULL) {
+			free(ret);
+			return NULL;
+		}
+		ret = tmp;
+		memcpy(ret + rlen, m->name, nlen + 1);
+		rlen += nlen;
+	}
+	return ret;
+}
+
+static int
+mac_setup_by_alg(struct sshmac *mac, const struct macalg *macalg)
+{
+	mac->type = macalg->type;
+	if (mac->type == SSH_DIGEST) {
+		if ((mac->hmac_ctx = ssh_hmac_start(macalg->alg)) == NULL)
+			return SSH_ERR_ALLOC_FAIL;
+		mac->key_len = mac->mac_len = ssh_hmac_bytes(macalg->alg);
 	} else {
-		mac->mac_len = macs[which].len / 8;
-		mac->key_len = macs[which].key_len / 8;
+		mac->mac_len = macalg->len / 8;
+		mac->key_len = macalg->key_len / 8;
 		mac->umac_ctx = NULL;
 	}
-	if (macs[which].truncatebits != 0)
-		mac->mac_len = macs[which].truncatebits / 8;
+	if (macalg->truncatebits != 0)
+		mac->mac_len = macalg->truncatebits / 8;
+	mac->etm = macalg->etm;
+	return 0;
 }
 
 int
-mac_setup(Mac *mac, char *name)
+mac_setup(struct sshmac *mac, char *name)
 {
-	int i;
+	const struct macalg *m;
 
-	for (i = 0; macs[i].name; i++) {
-		if (strcmp(name, macs[i].name) == 0) {
-			if (mac != NULL)
-				mac_setup_by_id(mac, i);
-			debug2("mac_setup: found %s", name);
-			return (0);
-		}
+	for (m = macs; m->name != NULL; m++) {
+		if (strcmp(name, m->name) != 0)
+			continue;
+		if (mac != NULL)
+			return mac_setup_by_alg(mac, m);
+		return 0;
 	}
-	debug2("mac_setup: unknown %s", name);
-	return (-1);
+	return SSH_ERR_INVALID_ARGUMENT;
 }
 
 int
-mac_init(Mac *mac)
+mac_init(struct sshmac *mac)
 {
 	if (mac->key == NULL)
-		fatal("mac_init: no key");
+		return SSH_ERR_INVALID_ARGUMENT;
 	switch (mac->type) {
-	case SSH_EVP:
-		if (mac->evp_md == NULL)
-			return -1;
-		HMAC_Init(&mac->evp_ctx, mac->key, mac->key_len, mac->evp_md);
+	case SSH_DIGEST:
+		if (mac->hmac_ctx == NULL ||
+		    ssh_hmac_init(mac->hmac_ctx, mac->key, mac->key_len) < 0)
+			return SSH_ERR_INVALID_ARGUMENT;
 		return 0;
 	case SSH_UMAC:
-		mac->umac_ctx = umac_new(mac->key);
+		if ((mac->umac_ctx = umac_new(mac->key)) == NULL)
+			return SSH_ERR_ALLOC_FAIL;
+		return 0;
+	case SSH_UMAC128:
+		if ((mac->umac_ctx = umac128_new(mac->key)) == NULL)
+			return SSH_ERR_ALLOC_FAIL;
 		return 0;
 	default:
-		return -1;
+		return SSH_ERR_INVALID_ARGUMENT;
 	}
 }
 
-u_char *
-mac_compute(Mac *mac, u_int32_t seqno, u_char *data, int datalen)
+int
+mac_compute(struct sshmac *mac, u_int32_t seqno, const u_char *data, int datalen,
+    u_char *digest, size_t dlen)
 {
-	static u_char m[EVP_MAX_MD_SIZE];
-	u_char b[4], nonce[8];
+	static union {
+		u_char m[SSH_DIGEST_MAX_LENGTH];
+		u_int64_t for_align;
+	} u;
+	u_char b[4];
+	u_char nonce[8];
 
-	if (mac->mac_len > sizeof(m))
-		fatal("mac_compute: mac too long %u %lu",
-		    mac->mac_len, (u_long)sizeof(m));
+	if (mac->mac_len > sizeof(u))
+		return SSH_ERR_INTERNAL_ERROR;
 
 	switch (mac->type) {
-	case SSH_EVP:
+	case SSH_DIGEST:
 		put_u32(b, seqno);
 		/* reset HMAC context */
-		HMAC_Init(&mac->evp_ctx, NULL, 0, NULL);
-		HMAC_Update(&mac->evp_ctx, b, sizeof(b));
-		HMAC_Update(&mac->evp_ctx, data, datalen);
-		HMAC_Final(&mac->evp_ctx, m, NULL);
+		if (ssh_hmac_init(mac->hmac_ctx, NULL, 0) < 0 ||
+		    ssh_hmac_update(mac->hmac_ctx, b, sizeof(b)) < 0 ||
+		    ssh_hmac_update(mac->hmac_ctx, data, datalen) < 0 ||
+		    ssh_hmac_final(mac->hmac_ctx, u.m, sizeof(u.m)) < 0)
+			return SSH_ERR_LIBCRYPTO_ERROR;
 		break;
 	case SSH_UMAC:
-		put_u64(nonce, seqno);
+		POKE_U64(nonce, seqno);
 		umac_update(mac->umac_ctx, data, datalen);
-		umac_final(mac->umac_ctx, m, nonce);
+		umac_final(mac->umac_ctx, u.m, nonce);
+		break;
+	case SSH_UMAC128:
+		put_u64(nonce, seqno);
+		umac128_update(mac->umac_ctx, data, datalen);
+		umac128_final(mac->umac_ctx, u.m, nonce);
 		break;
 	default:
-		fatal("mac_compute: unknown MAC type");
+		return SSH_ERR_INVALID_ARGUMENT;
 	}
-	return (m);
+	if (digest != NULL) {
+		if (dlen > mac->mac_len)
+			dlen = mac->mac_len;
+		memcpy(digest, u.m, dlen);
+	}
+	return 0;
 }
 
 void
-mac_clear(Mac *mac)
+mac_clear(struct sshmac *mac)
 {
 	if (mac->type == SSH_UMAC) {
 		if (mac->umac_ctx != NULL)
 			umac_delete(mac->umac_ctx);
-	} else if (mac->evp_md != NULL)
-		HMAC_cleanup(&mac->evp_ctx);
-	mac->evp_md = NULL;
+	} else if (mac->type == SSH_UMAC128) {
+		if (mac->umac_ctx != NULL)
+			umac128_delete(mac->umac_ctx);
+	} else if (mac->hmac_ctx != NULL)
+		ssh_hmac_free(mac->hmac_ctx);
+	mac->hmac_ctx = NULL;
 	mac->umac_ctx = NULL;
 }
 
@@ -178,19 +236,16 @@
 	char *maclist, *cp, *p;
 
 	if (names == NULL || strcmp(names, "") == 0)
-		return (0);
-	maclist = cp = xstrdup(names);
+		return 0;
+	if ((maclist = cp = strdup(names)) == NULL)
+		return 0;
 	for ((p = strsep(&cp, MAC_SEP)); p && *p != '\0';
 	    (p = strsep(&cp, MAC_SEP))) {
 		if (mac_setup(NULL, p) < 0) {
-			debug("bad mac %s [%s]", p, names);
-			xfree(maclist);
-			return (0);
-		} else {
-			debug3("mac ok: %s [%s]", p, names);
+			free(maclist);
+			return 0;
 		}
 	}
-	debug3("macs ok: [%s]", names);
-	xfree(maclist);
-	return (1);
+	free(maclist);
+	return 1;
 }