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/cipher-chachapoly.c b/cipher-chachapoly.c
new file mode 100644
index 0000000..7f31ff4
--- /dev/null
+++ b/cipher-chachapoly.c
@@ -0,0 +1,118 @@
+/*
+ * Copyright (c) 2013 Damien Miller <djm@mindrot.org>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+/* $OpenBSD: cipher-chachapoly.c,v 1.7 2015/01/14 10:24:42 markus Exp $ */
+
+#include "includes.h"
+
+#include <sys/types.h>
+#include <stdarg.h> /* needed for log.h */
+#include <string.h>
+#include <stdio.h> /* needed for misc.h */
+
+#include "log.h"
+#include "sshbuf.h"
+#include "ssherr.h"
+#include "cipher-chachapoly.h"
+
+int chachapoly_init(struct chachapoly_ctx *ctx,
+ const u_char *key, u_int keylen)
+{
+ if (keylen != (32 + 32)) /* 2 x 256 bit keys */
+ return SSH_ERR_INVALID_ARGUMENT;
+ chacha_keysetup(&ctx->main_ctx, key, 256);
+ chacha_keysetup(&ctx->header_ctx, key + 32, 256);
+ return 0;
+}
+
+/*
+ * chachapoly_crypt() operates as following:
+ * En/decrypt with header key 'aadlen' bytes from 'src', storing result
+ * to 'dest'. The ciphertext here is treated as additional authenticated
+ * data for MAC calculation.
+ * En/decrypt 'len' bytes at offset 'aadlen' from 'src' to 'dest'. Use
+ * POLY1305_TAGLEN bytes at offset 'len'+'aadlen' as the authentication
+ * tag. This tag is written on encryption and verified on decryption.
+ */
+int
+chachapoly_crypt(struct chachapoly_ctx *ctx, u_int seqnr, u_char *dest,
+ const u_char *src, u_int len, u_int aadlen, u_int authlen, int do_encrypt)
+{
+ u_char seqbuf[8];
+ const u_char one[8] = { 1, 0, 0, 0, 0, 0, 0, 0 }; /* NB little-endian */
+ u_char expected_tag[POLY1305_TAGLEN], poly_key[POLY1305_KEYLEN];
+ int r = SSH_ERR_INTERNAL_ERROR;
+
+ /*
+ * Run ChaCha20 once to generate the Poly1305 key. The IV is the
+ * packet sequence number.
+ */
+ memset(poly_key, 0, sizeof(poly_key));
+ POKE_U64(seqbuf, seqnr);
+ chacha_ivsetup(&ctx->main_ctx, seqbuf, NULL);
+ chacha_encrypt_bytes(&ctx->main_ctx,
+ poly_key, poly_key, sizeof(poly_key));
+
+ /* If decrypting, check tag before anything else */
+ if (!do_encrypt) {
+ const u_char *tag = src + aadlen + len;
+
+ poly1305_auth(expected_tag, src, aadlen + len, poly_key);
+ if (timingsafe_bcmp(expected_tag, tag, POLY1305_TAGLEN) != 0) {
+ r = SSH_ERR_MAC_INVALID;
+ goto out;
+ }
+ }
+
+ /* Crypt additional data */
+ if (aadlen) {
+ chacha_ivsetup(&ctx->header_ctx, seqbuf, NULL);
+ chacha_encrypt_bytes(&ctx->header_ctx, src, dest, aadlen);
+ }
+
+ /* Set Chacha's block counter to 1 */
+ chacha_ivsetup(&ctx->main_ctx, seqbuf, one);
+ chacha_encrypt_bytes(&ctx->main_ctx, src + aadlen,
+ dest + aadlen, len);
+
+ /* If encrypting, calculate and append tag */
+ if (do_encrypt) {
+ poly1305_auth(dest + aadlen + len, dest, aadlen + len,
+ poly_key);
+ }
+ r = 0;
+ out:
+ explicit_bzero(expected_tag, sizeof(expected_tag));
+ explicit_bzero(seqbuf, sizeof(seqbuf));
+ explicit_bzero(poly_key, sizeof(poly_key));
+ return r;
+}
+
+/* Decrypt and extract the encrypted packet length */
+int
+chachapoly_get_length(struct chachapoly_ctx *ctx,
+ u_int *plenp, u_int seqnr, const u_char *cp, u_int len)
+{
+ u_char buf[4], seqbuf[8];
+
+ if (len < 4)
+ return SSH_ERR_MESSAGE_INCOMPLETE;
+ POKE_U64(seqbuf, seqnr);
+ chacha_ivsetup(&ctx->header_ctx, seqbuf, NULL);
+ chacha_encrypt_bytes(&ctx->header_ctx, cp, buf, 4);
+ *plenp = PEEK_U32(buf);
+ return 0;
+}