From 5b01421b3f5cccdc9fc7cb35ce0ed62c9ec1e27d Mon Sep 17 00:00:00 2001
From: djm <djm>
Date: Thu, 5 Mar 2009 13:58:22 +0000
Subject: [PATCH]    - djm@cvs.openbsd.org 2009/03/05 07:18:19     
 [auth2-jpake.c jpake.c jpake.h monitor_wrap.c monitor_wrap.h schnorr.c]     
 [sshconnect2.c]      refactor the (disabled) Schnorr proof code to make it a
 little more      generally useful

---
 ChangeLog      |   8 ++
 auth2-jpake.c  |   5 +-
 jpake.c        | 181 ++----------------------
 jpake.h        |  38 ++---
 monitor_wrap.c |   9 +-
 monitor_wrap.h |  10 +-
 schnorr.c      | 374 ++++++++++++++++++++++++++++++++++++++++---------
 schnorr.h      |  60 ++++++++
 sshconnect2.c  |   3 +-
 9 files changed, 411 insertions(+), 277 deletions(-)
 create mode 100644 schnorr.h

diff --git a/ChangeLog b/ChangeLog
index f802c0d7..dde0669b 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+20090306
+ - (djm) OpenBSD CVS Sync
+   - djm@cvs.openbsd.org 2009/03/05 07:18:19
+     [auth2-jpake.c jpake.c jpake.h monitor_wrap.c monitor_wrap.h schnorr.c]
+     [sshconnect2.c]
+     refactor the (disabled) Schnorr proof code to make it a little more
+     generally useful
+
 20090223
  - (djm) OpenBSD CVS Sync
    - djm@cvs.openbsd.org 2009/02/22 23:50:57
diff --git a/auth2-jpake.c b/auth2-jpake.c
index efe7ff2a..6092e31c 100644
--- a/auth2-jpake.c
+++ b/auth2-jpake.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: auth2-jpake.c,v 1.2 2008/11/07 23:34:48 dtucker Exp $ */
+/* $OpenBSD: auth2-jpake.c,v 1.3 2009/03/05 07:18:19 djm Exp $ */
 /*
  * Copyright (c) 2008 Damien Miller.  All rights reserved.
  *
@@ -55,6 +55,7 @@
 #endif
 #include "monitor_wrap.h"
 
+#include "schnorr.h"
 #include "jpake.h"
 
 /*
@@ -359,7 +360,7 @@ auth2_jpake_get_pwdata(Authctxt *authctxt, BIGNUM **s,
 }
 
 /*
- * Being authentication attempt.
+ * Begin authentication attempt.
  * Note, sets authctxt->postponed while in subprotocol
  */
 static int
diff --git a/jpake.c b/jpake.c
index 565f2e25..13066106 100644
--- a/jpake.c
+++ b/jpake.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: jpake.c,v 1.1 2008/11/04 08:22:12 djm Exp $ */
+/* $OpenBSD: jpake.c,v 1.2 2009/03/05 07:18:19 djm Exp $ */
 /*
  * Copyright (c) 2008 Damien Miller.  All rights reserved.
  *
@@ -47,6 +47,7 @@
 #include "log.h"
 
 #include "jpake.h"
+#include "schnorr.h"
 
 #ifdef JPAKE
 
@@ -60,165 +61,10 @@
 	"98DA48361C55D39A69163FA8FD24CF5F83655D23DCA3AD961C62F356208552BB" \
 	"9ED529077096966D670C354E4ABC9804F1746C08CA237327FFFFFFFFFFFFFFFF"
 
-struct jpake_group *
+struct modp_group *
 jpake_default_group(void)
 {
-	struct jpake_group *ret;
-
-	ret = xmalloc(sizeof(*ret));
-	ret->p = ret->q = ret->g = NULL;
-	if (BN_hex2bn(&ret->p, JPAKE_GROUP_P) == 0 ||
-	    BN_hex2bn(&ret->g, JPAKE_GROUP_G) == 0)
-		fatal("%s: BN_hex2bn", __func__);
-	/* Subgroup order is p/2 (p is a safe prime) */
-	if ((ret->q = BN_new()) == NULL)
-		fatal("%s: BN_new", __func__);
-	if (BN_rshift1(ret->q, ret->p) != 1)
-		fatal("%s: BN_rshift1", __func__);
-
-	return ret;
-}
-
-/*
- * Generate uniformly distributed random number in range (1, high).
- * Return number on success, NULL on failure.
- */
-BIGNUM *
-bn_rand_range_gt_one(const BIGNUM *high)
-{
-	BIGNUM *r, *tmp;
-	int success = -1;
-
-	if ((tmp = BN_new()) == NULL) {
-		error("%s: BN_new", __func__);
-		return NULL;
-	}
-	if ((r = BN_new()) == NULL) {
-		error("%s: BN_new failed", __func__);
-		goto out;
-	}
-	if (BN_set_word(tmp, 2) != 1) {
-		error("%s: BN_set_word(tmp, 2)", __func__);
-		goto out;
-	}
-	if (BN_sub(tmp, high, tmp) == -1) {
-		error("%s: BN_sub failed (tmp = high - 2)", __func__);
-		goto out;
-	}
-	if (BN_rand_range(r, tmp) == -1) {
-		error("%s: BN_rand_range failed", __func__);
-		goto out;
-	}
-	if (BN_set_word(tmp, 2) != 1) {
-		error("%s: BN_set_word(tmp, 2)", __func__);
-		goto out;
-	}
-	if (BN_add(r, r, tmp) == -1) {
-		error("%s: BN_add failed (r = r + 2)", __func__);
-		goto out;
-	}
-	success = 0;
- out:
-	BN_clear_free(tmp);
-	if (success == 0)
-		return r;
-	BN_clear_free(r);
-	return NULL;
-}
-
-/*
- * Hash contents of buffer 'b' with hash 'md'. Returns 0 on success,
- * with digest via 'digestp' (caller to free) and length via 'lenp'.
- * Returns -1 on failure.
- */
-int
-hash_buffer(const u_char *buf, u_int len, const EVP_MD *md,
-    u_char **digestp, u_int *lenp)
-{
-	u_char digest[EVP_MAX_MD_SIZE];
-	u_int digest_len;
-	EVP_MD_CTX evp_md_ctx;
-	int success = -1;
-
-	EVP_MD_CTX_init(&evp_md_ctx);
-
-	if (EVP_DigestInit_ex(&evp_md_ctx, md, NULL) != 1) {
-		error("%s: EVP_DigestInit_ex", __func__);
-		goto out;
-	}
-	if (EVP_DigestUpdate(&evp_md_ctx, buf, len) != 1) {
-		error("%s: EVP_DigestUpdate", __func__);
-		goto out;
-	}
-	if (EVP_DigestFinal_ex(&evp_md_ctx, digest, &digest_len) != 1) {
-		error("%s: EVP_DigestFinal_ex", __func__);
-		goto out;
-	}
-	*digestp = xmalloc(digest_len);
-	*lenp = digest_len;
-	memcpy(*digestp, digest, *lenp);
-	success = 0;
- out:
-	EVP_MD_CTX_cleanup(&evp_md_ctx);
-	bzero(digest, sizeof(digest));
-	digest_len = 0;
-	return success;
-}
-
-/* print formatted string followed by bignum */
-void
-jpake_debug3_bn(const BIGNUM *n, const char *fmt, ...)
-{
-	char *out, *h;
-	va_list args;
-
-	out = NULL;
-	va_start(args, fmt);
-	vasprintf(&out, fmt, args);
-	va_end(args);
-	if (out == NULL)
-		fatal("%s: vasprintf failed", __func__);
-
-	if (n == NULL)
-		debug3("%s(null)", out);
-	else {
-		h = BN_bn2hex(n);
-		debug3("%s0x%s", out, h);
-		free(h);
-	}
-	free(out);
-}
-
-/* print formatted string followed by buffer contents in hex */
-void
-jpake_debug3_buf(const u_char *buf, u_int len, const char *fmt, ...)
-{
-	char *out, h[65];
-	u_int i, j;
-	va_list args;
-
-	out = NULL;
-	va_start(args, fmt);
-	vasprintf(&out, fmt, args);
-	va_end(args);
-	if (out == NULL)
-		fatal("%s: vasprintf failed", __func__);
-
-	debug3("%s length %u%s", out, len, buf == NULL ? " (null)" : "");
-	free(out);
-	if (buf == NULL)
-		return;
-
-	*h = '\0';
-	for (i = j = 0; i < len; i++) {
-		snprintf(h + j, sizeof(h) - j, "%02x", buf[i]);
-		j += 2;
-		if (j >= sizeof(h) - 1 || i == len - 1) {
-			debug3("    %s", h);
-			*h = '\0';
-			j = 0;
-		}
-	}
+	return modp_group_from_g_and_safe_p(JPAKE_GROUP_G, JPAKE_GROUP_P);
 }
 
 struct jpake_ctx *
@@ -243,7 +89,6 @@ jpake_new(void)
 	return ret;
 }
 
-
 void
 jpake_free(struct jpake_ctx *pctx)
 {
@@ -344,7 +189,7 @@ jpake_dump(struct jpake_ctx *pctx, const char *fmt, ...)
 
 /* Shared parts of step 1 exchange calculation */
 void
-jpake_step1(struct jpake_group *grp,
+jpake_step1(struct modp_group *grp,
     u_char **id, u_int *id_len,
     BIGNUM **priv1, BIGNUM **priv2, BIGNUM **g_priv1, BIGNUM **g_priv2,
     u_char **priv1_proof, u_int *priv1_proof_len,
@@ -383,11 +228,11 @@ jpake_step1(struct jpake_group *grp,
 		fatal("%s: BN_mod_exp", __func__);
 
 	/* Generate proofs for holding x1/x3 and x2/x4 */
-	if (schnorr_sign(grp->p, grp->q, grp->g,
+	if (schnorr_sign_buf(grp->p, grp->q, grp->g,
 	    *priv1, *g_priv1, *id, *id_len,
 	    priv1_proof, priv1_proof_len) != 0)
 		fatal("%s: schnorr_sign", __func__);
-	if (schnorr_sign(grp->p, grp->q, grp->g,
+	if (schnorr_sign_buf(grp->p, grp->q, grp->g,
 	    *priv2, *g_priv2, *id, *id_len,
 	    priv2_proof, priv2_proof_len) != 0)
 		fatal("%s: schnorr_sign", __func__);
@@ -397,7 +242,7 @@ jpake_step1(struct jpake_group *grp,
 
 /* Shared parts of step 2 exchange calculation */
 void
-jpake_step2(struct jpake_group *grp, BIGNUM *s,
+jpake_step2(struct modp_group *grp, BIGNUM *s,
     BIGNUM *mypub1, BIGNUM *theirpub1, BIGNUM *theirpub2, BIGNUM *mypriv2,
     const u_char *theirid, u_int theirid_len,
     const u_char *myid, u_int myid_len,
@@ -415,10 +260,10 @@ jpake_step2(struct jpake_group *grp, BIGNUM *s,
 	if (BN_cmp(theirpub2, BN_value_one()) <= 0)
 		fatal("%s: theirpub2 <= 1", __func__);
 
-	if (schnorr_verify(grp->p, grp->q, grp->g, theirpub1,
+	if (schnorr_verify_buf(grp->p, grp->q, grp->g, theirpub1,
 	    theirid, theirid_len, theirpub1_proof, theirpub1_proof_len) != 1)
 		fatal("%s: schnorr_verify theirpub1 failed", __func__);
-	if (schnorr_verify(grp->p, grp->q, grp->g, theirpub2,
+	if (schnorr_verify_buf(grp->p, grp->q, grp->g, theirpub2,
 	    theirid, theirid_len, theirpub2_proof, theirpub2_proof_len) != 1)
 		fatal("%s: schnorr_verify theirpub2 failed", __func__);
 
@@ -459,7 +304,7 @@ jpake_step2(struct jpake_group *grp, BIGNUM *s,
 	JPAKE_DEBUG_BN((exponent, "%s: exponent = ", __func__));
 
 	/* Note the generator here is 'tmp', not g */
-	if (schnorr_sign(grp->p, grp->q, tmp, exponent, *newpub,
+	if (schnorr_sign_buf(grp->p, grp->q, tmp, exponent, *newpub,
 	    myid, myid_len,
 	    newpub_exponent_proof, newpub_exponent_proof_len) != 0)
 		fatal("%s: schnorr_sign newpub", __func__);
@@ -496,7 +341,7 @@ jpake_confirm_hash(const BIGNUM *k,
 
 /* Shared parts of key derivation and confirmation calculation */
 void
-jpake_key_confirm(struct jpake_group *grp, BIGNUM *s, BIGNUM *step2_val,
+jpake_key_confirm(struct modp_group *grp, BIGNUM *s, BIGNUM *step2_val,
     BIGNUM *mypriv2, BIGNUM *mypub1, BIGNUM *mypub2,
     BIGNUM *theirpub1, BIGNUM *theirpub2,
     const u_char *my_id, u_int my_id_len,
@@ -531,7 +376,7 @@ jpake_key_confirm(struct jpake_group *grp, BIGNUM *s, BIGNUM *step2_val,
 
 	JPAKE_DEBUG_BN((tmp, "%s: tmp = ", __func__));
 
-	if (schnorr_verify(grp->p, grp->q, tmp, step2_val, 
+	if (schnorr_verify_buf(grp->p, grp->q, tmp, step2_val, 
 	    their_id, their_id_len,
 	    theirpriv2_s_proof, theirpriv2_s_proof_len) != 1)
 		fatal("%s: schnorr_verify theirpriv2_s_proof failed", __func__);
diff --git a/jpake.h b/jpake.h
index a3d800cd..a3f2cf02 100644
--- a/jpake.h
+++ b/jpake.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: jpake.h,v 1.1 2008/11/04 08:22:13 djm Exp $ */
+/* $OpenBSD: jpake.h,v 1.2 2009/03/05 07:18:19 djm Exp $ */
 /*
  * Copyright (c) 2008 Damien Miller.  All rights reserved.
  *
@@ -28,20 +28,16 @@
 # define JPAKE_DEBUG_BUF(a)
 # define JPAKE_DEBUG_CTX(a)
 #else
-# define JPAKE_DEBUG_BN(a)	jpake_debug3_bn a
-# define JPAKE_DEBUG_BUF(a)	jpake_debug3_buf a
+# define JPAKE_DEBUG_BN(a)	debug3_bn a
+# define JPAKE_DEBUG_BUF(a)	debug3_buf a
 # define JPAKE_DEBUG_CTX(a)	jpake_dump a
-#endif /* SCHNORR_DEBUG */
-
-struct jpake_group {
-	BIGNUM *p, *q, *g;
-};
+#endif /* JPAKE_DEBUG */
 
 #define KZP_ID_LEN	16	/* Length of client and server IDs */
 
 struct jpake_ctx {
 	/* Parameters */
-	struct jpake_group *grp;
+	struct modp_group *grp;
 
 	/* Private values shared by client and server */
 	BIGNUM *s;			/* Secret (salted, crypted password) */
@@ -83,26 +79,18 @@ struct jpake_ctx {
 };
 
 /* jpake.c */
-struct jpake_group *jpake_default_group(void);
-BIGNUM *bn_rand_range_gt_one(const BIGNUM *high);
-int hash_buffer(const u_char *, u_int, const EVP_MD *, u_char **, u_int *);
-void jpake_debug3_bn(const BIGNUM *, const char *, ...)
-    __attribute__((__nonnull__ (2)))
-    __attribute__((format(printf, 2, 3)));
-void jpake_debug3_buf(const u_char *, u_int, const char *, ...)
-    __attribute__((__nonnull__ (3)))
-    __attribute__((format(printf, 3, 4)));
+struct modp_group *jpake_default_group(void);
 void jpake_dump(struct jpake_ctx *, const char *, ...)
     __attribute__((__nonnull__ (2)))
     __attribute__((format(printf, 2, 3)));
 struct jpake_ctx *jpake_new(void);
 void jpake_free(struct jpake_ctx *);
 
-void jpake_step1(struct jpake_group *, u_char **, u_int *,
+void jpake_step1(struct modp_group *, u_char **, u_int *,
     BIGNUM **, BIGNUM **, BIGNUM **, BIGNUM **,
     u_char **, u_int *, u_char **, u_int *);
 
-void jpake_step2(struct jpake_group *, BIGNUM *,
+void jpake_step2(struct modp_group *, BIGNUM *,
     BIGNUM *, BIGNUM *, BIGNUM *, BIGNUM *,
     const u_char *, u_int, const u_char *, u_int,
     const u_char *, u_int, const u_char *, u_int,
@@ -113,7 +101,7 @@ void jpake_confirm_hash(const BIGNUM *,
     const u_char *, u_int,
     u_char **, u_int *);
 
-void jpake_key_confirm(struct jpake_group *, BIGNUM *, BIGNUM *,
+void jpake_key_confirm(struct modp_group *, BIGNUM *, BIGNUM *,
     BIGNUM *, BIGNUM *, BIGNUM *, BIGNUM *, BIGNUM *,
     const u_char *, u_int, const u_char *, u_int,
     const u_char *, u_int, const u_char *, u_int,
@@ -122,13 +110,5 @@ void jpake_key_confirm(struct jpake_group *, BIGNUM *, BIGNUM *,
 int jpake_check_confirm(const BIGNUM *, const u_char *, u_int,
     const u_char *, u_int, const u_char *, u_int);
 
-/* schnorr.c */
-int schnorr_sign(const BIGNUM *, const BIGNUM *, const BIGNUM *,
-    const BIGNUM *, const BIGNUM *, const u_char *, u_int ,
-    u_char **, u_int *);
-int schnorr_verify(const BIGNUM *, const BIGNUM *, const BIGNUM *, 
-    const BIGNUM *, const u_char *, u_int,
-    const u_char *, u_int);
-
 #endif /* JPAKE_H */
 
diff --git a/monitor_wrap.c b/monitor_wrap.c
index 0986fc51..db3251b9 100644
--- a/monitor_wrap.c
+++ b/monitor_wrap.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: monitor_wrap.c,v 1.64 2008/11/04 08:22:13 djm Exp $ */
+/* $OpenBSD: monitor_wrap.c,v 1.65 2009/03/05 07:18:19 djm Exp $ */
 /*
  * Copyright 2002 Niels Provos <provos@citi.umich.edu>
  * Copyright 2002 Markus Friedl <markus@openbsd.org>
@@ -71,6 +71,7 @@
 #include "atomicio.h"
 #include "monitor_fdpass.h"
 #include "misc.h"
+#include "schnorr.h"
 #include "jpake.h"
 
 #include "channels.h"
@@ -1282,7 +1283,7 @@ mm_auth2_jpake_get_pwdata(Authctxt *authctxt, BIGNUM **s,
 }
 
 void
-mm_jpake_step1(struct jpake_group *grp,
+mm_jpake_step1(struct modp_group *grp,
     u_char **id, u_int *id_len,
     BIGNUM **priv1, BIGNUM **priv2, BIGNUM **g_priv1, BIGNUM **g_priv2,
     u_char **priv1_proof, u_int *priv1_proof_len,
@@ -1317,7 +1318,7 @@ mm_jpake_step1(struct jpake_group *grp,
 }
 
 void
-mm_jpake_step2(struct jpake_group *grp, BIGNUM *s,
+mm_jpake_step2(struct modp_group *grp, BIGNUM *s,
     BIGNUM *mypub1, BIGNUM *theirpub1, BIGNUM *theirpub2, BIGNUM *mypriv2,
     const u_char *theirid, u_int theirid_len,
     const u_char *myid, u_int myid_len,
@@ -1357,7 +1358,7 @@ mm_jpake_step2(struct jpake_group *grp, BIGNUM *s,
 }
 
 void
-mm_jpake_key_confirm(struct jpake_group *grp, BIGNUM *s, BIGNUM *step2_val,
+mm_jpake_key_confirm(struct modp_group *grp, BIGNUM *s, BIGNUM *step2_val,
     BIGNUM *mypriv2, BIGNUM *mypub1, BIGNUM *mypub2,
     BIGNUM *theirpub1, BIGNUM *theirpub2,
     const u_char *my_id, u_int my_id_len,
diff --git a/monitor_wrap.h b/monitor_wrap.h
index 55c4b99f..de2d16f6 100644
--- a/monitor_wrap.h
+++ b/monitor_wrap.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: monitor_wrap.h,v 1.21 2008/11/04 08:22:13 djm Exp $ */
+/* $OpenBSD: monitor_wrap.h,v 1.22 2009/03/05 07:18:19 djm Exp $ */
 
 /*
  * Copyright 2002 Niels Provos <provos@citi.umich.edu>
@@ -102,17 +102,17 @@ int mm_skey_query(void *, char **, char **, u_int *, char ***, u_int **);
 int mm_skey_respond(void *, u_int, char **);
 
 /* jpake */
-struct jpake_group;
+struct modp_group;
 void mm_auth2_jpake_get_pwdata(struct Authctxt *, BIGNUM **, char **, char **);
-void mm_jpake_step1(struct jpake_group *, u_char **, u_int *,
+void mm_jpake_step1(struct modp_group *, u_char **, u_int *,
     BIGNUM **, BIGNUM **, BIGNUM **, BIGNUM **,
     u_char **, u_int *, u_char **, u_int *);
-void mm_jpake_step2(struct jpake_group *, BIGNUM *,
+void mm_jpake_step2(struct modp_group *, BIGNUM *,
     BIGNUM *, BIGNUM *, BIGNUM *, BIGNUM *,
     const u_char *, u_int, const u_char *, u_int,
     const u_char *, u_int, const u_char *, u_int,
     BIGNUM **, u_char **, u_int *);
-void mm_jpake_key_confirm(struct jpake_group *, BIGNUM *, BIGNUM *,
+void mm_jpake_key_confirm(struct modp_group *, BIGNUM *, BIGNUM *,
     BIGNUM *, BIGNUM *, BIGNUM *, BIGNUM *, BIGNUM *,
     const u_char *, u_int, const u_char *, u_int,
     const u_char *, u_int, const u_char *, u_int,
diff --git a/schnorr.c b/schnorr.c
index 54697507..7b97b556 100644
--- a/schnorr.c
+++ b/schnorr.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: schnorr.c,v 1.2 2009/02/18 04:31:21 djm Exp $ */
+/* $OpenBSD: schnorr.c,v 1.3 2009/03/05 07:18:19 djm Exp $ */
 /*
  * Copyright (c) 2008 Damien Miller.  All rights reserved.
  *
@@ -40,36 +40,32 @@
 #include "buffer.h"
 #include "log.h"
 
-#include "jpake.h"
+#include "schnorr.h"
 
 /* #define SCHNORR_DEBUG */		/* Privacy-violating debugging */
 /* #define SCHNORR_MAIN */		/* Include main() selftest */
 
-/* XXX */
-/* Parametise signature hash? (sha256, sha1, etc.) */
-/* Signature format - include type name, hash type, group params? */
-
 #ifndef SCHNORR_DEBUG
 # define SCHNORR_DEBUG_BN(a)
 # define SCHNORR_DEBUG_BUF(a)
 #else
-# define SCHNORR_DEBUG_BN(a)	jpake_debug3_bn a
-# define SCHNORR_DEBUG_BUF(a)	jpake_debug3_buf a
+# define SCHNORR_DEBUG_BN(a)	debug3_bn a
+# define SCHNORR_DEBUG_BUF(a)	debug3_buf a
 #endif /* SCHNORR_DEBUG */
 
 /*
  * Calculate hash component of Schnorr signature H(g || g^v || g^x || id)
- * using SHA1. Returns signature as bignum or NULL on error.
+ * using the hash function defined by "evp_md". Returns signature as
+ * bignum or NULL on error.
  */
 static BIGNUM *
 schnorr_hash(const BIGNUM *p, const BIGNUM *q, const BIGNUM *g,
-    const BIGNUM *g_v, const BIGNUM *g_x,
+    const EVP_MD *evp_md, const BIGNUM *g_v, const BIGNUM *g_x,
     const u_char *id, u_int idlen)
 {
 	u_char *digest;
 	u_int digest_len;
 	BIGNUM *h;
-	EVP_MD_CTX evp_md_ctx;
 	Buffer b;
 	int success = -1;
 
@@ -79,7 +75,6 @@ schnorr_hash(const BIGNUM *p, const BIGNUM *q, const BIGNUM *g,
 	}
 
 	buffer_init(&b);
-	EVP_MD_CTX_init(&evp_md_ctx);
 
 	/* h = H(g || p || q || g^v || g^x || id) */
 	buffer_put_bignum2(&b, g);
@@ -91,7 +86,7 @@ schnorr_hash(const BIGNUM *p, const BIGNUM *q, const BIGNUM *g,
 
 	SCHNORR_DEBUG_BUF((buffer_ptr(&b), buffer_len(&b),
 	    "%s: hashblob", __func__));
-	if (hash_buffer(buffer_ptr(&b), buffer_len(&b), EVP_sha256(),
+	if (hash_buffer(buffer_ptr(&b), buffer_len(&b), evp_md,
 	    &digest, &digest_len) != 0) {
 		error("%s: hash_buffer", __func__);
 		goto out;
@@ -104,7 +99,6 @@ schnorr_hash(const BIGNUM *p, const BIGNUM *q, const BIGNUM *g,
 	SCHNORR_DEBUG_BN((h, "%s: h = ", __func__));
  out:
 	buffer_free(&b);
-	EVP_MD_CTX_cleanup(&evp_md_ctx);
 	bzero(digest, digest_len);
 	xfree(digest);
 	digest_len = 0;
@@ -117,18 +111,20 @@ schnorr_hash(const BIGNUM *p, const BIGNUM *q, const BIGNUM *g,
 /*
  * Generate Schnorr signature to prove knowledge of private value 'x' used
  * in public exponent g^x, under group defined by 'grp_p', 'grp_q' and 'grp_g'
+ * using the hash function "evp_md".
  * 'idlen' bytes from 'id' will be included in the signature hash as an anti-
  * replay salt.
- * On success, 0 is returned and *siglen bytes of signature are returned in
- * *sig (caller to free). Returns -1 on failure.
+ * 
+ * On success, 0 is returned. The signature values are returned as *e_p
+ * (g^v mod p) and *r_p (v - xh mod q). The caller must free these values.
+ * On failure, -1 is returned.
  */
 int
 schnorr_sign(const BIGNUM *grp_p, const BIGNUM *grp_q, const BIGNUM *grp_g,
-    const BIGNUM *x, const BIGNUM *g_x, const u_char *id, u_int idlen,
-    u_char **sig, u_int *siglen)
+    const EVP_MD *evp_md, const BIGNUM *x, const BIGNUM *g_x,
+    const u_char *id, u_int idlen, BIGNUM **r_p, BIGNUM **e_p)
 {
 	int success = -1;
-	Buffer b;
 	BIGNUM *h, *tmp, *v, *g_v, *r;
 	BN_CTX *bn_ctx;
 
@@ -171,7 +167,7 @@ schnorr_sign(const BIGNUM *grp_p, const BIGNUM *grp_q, const BIGNUM *grp_g,
 	SCHNORR_DEBUG_BN((g_v, "%s: g_v = ", __func__));
 
 	/* h = H(g || g^v || g^x || id) */
-	if ((h = schnorr_hash(grp_p, grp_q, grp_g, g_v, g_x,
+	if ((h = schnorr_hash(grp_p, grp_q, grp_g, evp_md, g_v, g_x,
 	    id, idlen)) == NULL) {
 		error("%s: schnorr_hash failed", __func__);
 		goto out;
@@ -186,12 +182,49 @@ schnorr_sign(const BIGNUM *grp_p, const BIGNUM *grp_q, const BIGNUM *grp_g,
 		error("%s: BN_mod_mul (r = v - tmp)", __func__);
 		goto out;
 	}
+	SCHNORR_DEBUG_BN((g_v, "%s: e = ", __func__));
 	SCHNORR_DEBUG_BN((r, "%s: r = ", __func__));
 
-	/* Signature is (g_v, r) */
+	*e_p = g_v;
+	*r_p = r;
+
+	success = 0;
+ out:
+	BN_CTX_free(bn_ctx);
+	if (h != NULL)
+		BN_clear_free(h);
+	if (v != NULL)
+		BN_clear_free(v);
+	BN_clear_free(tmp);
+
+	return success;
+}
+
+/*
+ * Generate Schnorr signature to prove knowledge of private value 'x' used
+ * in public exponent g^x, under group defined by 'grp_p', 'grp_q' and 'grp_g'
+ * using a SHA256 hash.
+ * 'idlen' bytes from 'id' will be included in the signature hash as an anti-
+ * replay salt.
+ * On success, 0 is returned and *siglen bytes of signature are returned in
+ * *sig (caller to free). Returns -1 on failure.
+ */
+int
+schnorr_sign_buf(const BIGNUM *grp_p, const BIGNUM *grp_q, const BIGNUM *grp_g,
+    const BIGNUM *x, const BIGNUM *g_x, const u_char *id, u_int idlen,
+    u_char **sig, u_int *siglen)
+{
+	Buffer b;
+	BIGNUM *r, *e;
+
+	if (schnorr_sign(grp_p, grp_q, grp_g, EVP_sha256(),
+	    x, g_x, id, idlen, &r, &e) != 0)
+		return -1;
+
+	/* Signature is (e, r) */
 	buffer_init(&b);
 	/* XXX sigtype-hash as string? */
-	buffer_put_bignum2(&b, g_v);
+	buffer_put_bignum2(&b, e);
 	buffer_put_bignum2(&b, r);
 	*siglen = buffer_len(&b);
 	*sig = xmalloc(*siglen);
@@ -199,36 +232,28 @@ schnorr_sign(const BIGNUM *grp_p, const BIGNUM *grp_q, const BIGNUM *grp_g,
 	SCHNORR_DEBUG_BUF((buffer_ptr(&b), buffer_len(&b),
 	    "%s: sigblob", __func__));
 	buffer_free(&b);
-	success = 0;
- out:
-	BN_CTX_free(bn_ctx);
-	if (h != NULL)
-		BN_clear_free(h);
-	if (v != NULL)
-		BN_clear_free(v);
+
 	BN_clear_free(r);
-	BN_clear_free(g_v);
-	BN_clear_free(tmp);
+	BN_clear_free(e);
 
-	return success;
+	return 0;
 }
 
 /*
- * Verify Schnorr signature 'sig' of length 'siglen' against public exponent
- * g_x (g^x) under group defined by 'grp_p', 'grp_q' and 'grp_g'.
+ * Verify Schnorr signature { r (v - xh mod q), e (g^v mod p) } against
+ * public exponent g_x (g^x) under group defined by 'grp_p', 'grp_q' and
+ * 'grp_g' using hash "evp_md".
  * Signature hash will be salted with 'idlen' bytes from 'id'.
  * Returns -1 on failure, 0 on incorrect signature or 1 on matching signature.
  */
 int
 schnorr_verify(const BIGNUM *grp_p, const BIGNUM *grp_q, const BIGNUM *grp_g,
-    const BIGNUM *g_x, const u_char *id, u_int idlen,
-    const u_char *sig, u_int siglen)
+    const EVP_MD *evp_md, const BIGNUM *g_x, const u_char *id, u_int idlen,
+    const BIGNUM *r, const BIGNUM *e)
 {
 	int success = -1;
-	Buffer b;
-	BIGNUM *g_v, *h, *r, *g_xh, *g_r, *expected;
+	BIGNUM *h, *g_xh, *g_r, *expected;
 	BN_CTX *bn_ctx;
-	u_int rlen;
 
 	SCHNORR_DEBUG_BN((g_x, "%s: g_x = ", __func__));
 
@@ -238,39 +263,23 @@ schnorr_verify(const BIGNUM *grp_p, const BIGNUM *grp_q, const BIGNUM *grp_g,
 		return -1;
 	}
 
-	g_v = h = r = g_xh = g_r = expected = NULL;
+	h = g_xh = g_r = expected = NULL;
 	if ((bn_ctx = BN_CTX_new()) == NULL) {
 		error("%s: BN_CTX_new", __func__);
 		goto out;
 	}
-	if ((g_v = BN_new()) == NULL ||
-	    (r = BN_new()) == NULL ||
-	    (g_xh = BN_new()) == NULL ||
+	if ((g_xh = BN_new()) == NULL ||
 	    (g_r = BN_new()) == NULL ||
 	    (expected = BN_new()) == NULL) {
 		error("%s: BN_new", __func__);
 		goto out;
 	}
 
-	/* Extract g^v and r from signature blob */
-	buffer_init(&b);
-	buffer_append(&b, sig, siglen);
-	SCHNORR_DEBUG_BUF((buffer_ptr(&b), buffer_len(&b),
-	    "%s: sigblob", __func__));
-	buffer_get_bignum2(&b, g_v);
-	buffer_get_bignum2(&b, r);
-	rlen = buffer_len(&b);
-	buffer_free(&b);
-	if (rlen != 0) {
-		error("%s: remaining bytes in signature %d", __func__, rlen);
-		goto out;
-	}
-	buffer_free(&b);
-	SCHNORR_DEBUG_BN((g_v, "%s: g_v = ", __func__));
+	SCHNORR_DEBUG_BN((e, "%s: e = ", __func__));
 	SCHNORR_DEBUG_BN((r, "%s: r = ", __func__));
 
 	/* h = H(g || g^v || g^x || id) */
-	if ((h = schnorr_hash(grp_p, grp_q, grp_g, g_v, g_x,
+	if ((h = schnorr_hash(grp_p, grp_q, grp_g, evp_md, e, g_x,
 	    id, idlen)) == NULL) {
 		error("%s: schnorr_hash failed", __func__);
 		goto out;
@@ -297,20 +306,248 @@ schnorr_verify(const BIGNUM *grp_p, const BIGNUM *grp_q, const BIGNUM *grp_g,
 	}
 	SCHNORR_DEBUG_BN((expected, "%s: expected = ", __func__));
 
-	/* Check g_v == expected */
-	success = BN_cmp(expected, g_v) == 0;
+	/* Check e == expected */
+	success = BN_cmp(expected, e) == 0;
  out:
 	BN_CTX_free(bn_ctx);
 	if (h != NULL)
 		BN_clear_free(h);
-	BN_clear_free(g_v);
-	BN_clear_free(r);
 	BN_clear_free(g_xh);
 	BN_clear_free(g_r);
 	BN_clear_free(expected);
 	return success;
 }
 
+/*
+ * Verify Schnorr signature 'sig' of length 'siglen' against public exponent
+ * g_x (g^x) under group defined by 'grp_p', 'grp_q' and 'grp_g' using a
+ * SHA256 hash.
+ * Signature hash will be salted with 'idlen' bytes from 'id'.
+ * Returns -1 on failure, 0 on incorrect signature or 1 on matching signature.
+ */
+int
+schnorr_verify_buf(const BIGNUM *grp_p, const BIGNUM *grp_q,
+    const BIGNUM *grp_g,
+    const BIGNUM *g_x, const u_char *id, u_int idlen,
+    const u_char *sig, u_int siglen)
+{
+	Buffer b;
+	int ret = -1;
+	u_int rlen;
+	BIGNUM *r, *e;
+
+	e = r = NULL;
+	if ((e = BN_new()) == NULL ||
+	    (r = BN_new()) == NULL) {
+		error("%s: BN_new", __func__);
+		goto out;
+	}
+
+	/* Extract g^v and r from signature blob */
+	buffer_init(&b);
+	buffer_append(&b, sig, siglen);
+	SCHNORR_DEBUG_BUF((buffer_ptr(&b), buffer_len(&b),
+	    "%s: sigblob", __func__));
+	buffer_get_bignum2(&b, e);
+	buffer_get_bignum2(&b, r);
+	rlen = buffer_len(&b);
+	buffer_free(&b);
+	if (rlen != 0) {
+		error("%s: remaining bytes in signature %d", __func__, rlen);
+		goto out;
+	}
+
+	ret = schnorr_verify(grp_p, grp_q, grp_g, EVP_sha256(),
+	    g_x, id, idlen, r, e);
+ out:
+	BN_clear_free(e);
+	BN_clear_free(r);
+
+	return ret;
+}
+
+/* Helper functions */
+
+/*
+ * Generate uniformly distributed random number in range (1, high).
+ * Return number on success, NULL on failure.
+ */
+BIGNUM *
+bn_rand_range_gt_one(const BIGNUM *high)
+{
+	BIGNUM *r, *tmp;
+	int success = -1;
+
+	if ((tmp = BN_new()) == NULL) {
+		error("%s: BN_new", __func__);
+		return NULL;
+	}
+	if ((r = BN_new()) == NULL) {
+		error("%s: BN_new failed", __func__);
+		goto out;
+	}
+	if (BN_set_word(tmp, 2) != 1) {
+		error("%s: BN_set_word(tmp, 2)", __func__);
+		goto out;
+	}
+	if (BN_sub(tmp, high, tmp) == -1) {
+		error("%s: BN_sub failed (tmp = high - 2)", __func__);
+		goto out;
+	}
+	if (BN_rand_range(r, tmp) == -1) {
+		error("%s: BN_rand_range failed", __func__);
+		goto out;
+	}
+	if (BN_set_word(tmp, 2) != 1) {
+		error("%s: BN_set_word(tmp, 2)", __func__);
+		goto out;
+	}
+	if (BN_add(r, r, tmp) == -1) {
+		error("%s: BN_add failed (r = r + 2)", __func__);
+		goto out;
+	}
+	success = 0;
+ out:
+	BN_clear_free(tmp);
+	if (success == 0)
+		return r;
+	BN_clear_free(r);
+	return NULL;
+}
+
+/*
+ * Hash contents of buffer 'b' with hash 'md'. Returns 0 on success,
+ * with digest via 'digestp' (caller to free) and length via 'lenp'.
+ * Returns -1 on failure.
+ */
+int
+hash_buffer(const u_char *buf, u_int len, const EVP_MD *md,
+    u_char **digestp, u_int *lenp)
+{
+	u_char digest[EVP_MAX_MD_SIZE];
+	u_int digest_len;
+	EVP_MD_CTX evp_md_ctx;
+	int success = -1;
+
+	EVP_MD_CTX_init(&evp_md_ctx);
+
+	if (EVP_DigestInit_ex(&evp_md_ctx, md, NULL) != 1) {
+		error("%s: EVP_DigestInit_ex", __func__);
+		goto out;
+	}
+	if (EVP_DigestUpdate(&evp_md_ctx, buf, len) != 1) {
+		error("%s: EVP_DigestUpdate", __func__);
+		goto out;
+	}
+	if (EVP_DigestFinal_ex(&evp_md_ctx, digest, &digest_len) != 1) {
+		error("%s: EVP_DigestFinal_ex", __func__);
+		goto out;
+	}
+	*digestp = xmalloc(digest_len);
+	*lenp = digest_len;
+	memcpy(*digestp, digest, *lenp);
+	success = 0;
+ out:
+	EVP_MD_CTX_cleanup(&evp_md_ctx);
+	bzero(digest, sizeof(digest));
+	digest_len = 0;
+	return success;
+}
+
+/* print formatted string followed by bignum */
+void
+debug3_bn(const BIGNUM *n, const char *fmt, ...)
+{
+	char *out, *h;
+	va_list args;
+
+	out = NULL;
+	va_start(args, fmt);
+	vasprintf(&out, fmt, args);
+	va_end(args);
+	if (out == NULL)
+		fatal("%s: vasprintf failed", __func__);
+
+	if (n == NULL)
+		debug3("%s(null)", out);
+	else {
+		h = BN_bn2hex(n);
+		debug3("%s0x%s", out, h);
+		free(h);
+	}
+	free(out);
+}
+
+/* print formatted string followed by buffer contents in hex */
+void
+debug3_buf(const u_char *buf, u_int len, const char *fmt, ...)
+{
+	char *out, h[65];
+	u_int i, j;
+	va_list args;
+
+	out = NULL;
+	va_start(args, fmt);
+	vasprintf(&out, fmt, args);
+	va_end(args);
+	if (out == NULL)
+		fatal("%s: vasprintf failed", __func__);
+
+	debug3("%s length %u%s", out, len, buf == NULL ? " (null)" : "");
+	free(out);
+	if (buf == NULL)
+		return;
+
+	*h = '\0';
+	for (i = j = 0; i < len; i++) {
+		snprintf(h + j, sizeof(h) - j, "%02x", buf[i]);
+		j += 2;
+		if (j >= sizeof(h) - 1 || i == len - 1) {
+			debug3("    %s", h);
+			*h = '\0';
+			j = 0;
+		}
+	}
+}
+
+/*
+ * Construct a MODP group from hex strings p (which must be a safe
+ * prime) and g, automatically calculating subgroup q as (p / 2)
+ */
+struct modp_group *
+modp_group_from_g_and_safe_p(const char *grp_g, const char *grp_p)
+{
+	struct modp_group *ret;
+
+	ret = xmalloc(sizeof(*ret));
+	ret->p = ret->q = ret->g = NULL;
+	if (BN_hex2bn(&ret->p, grp_p) == 0 ||
+	    BN_hex2bn(&ret->g, grp_g) == 0)
+		fatal("%s: BN_hex2bn", __func__);
+	/* Subgroup order is p/2 (p is a safe prime) */
+	if ((ret->q = BN_new()) == NULL)
+		fatal("%s: BN_new", __func__);
+	if (BN_rshift1(ret->q, ret->p) != 1)
+		fatal("%s: BN_rshift1", __func__);
+
+	return ret;
+}
+
+void
+modp_group_free(struct modp_group *grp)
+{
+	if (grp->g != NULL)
+		BN_clear_free(grp->g);
+	if (grp->p != NULL)
+		BN_clear_free(grp->p);
+	if (grp->q != NULL)
+		BN_clear_free(grp->q);
+	bzero(grp, sizeof(*grp));
+	xfree(grp);
+}
+
+/* main() function for self-test */
+
 #ifdef SCHNORR_MAIN
 static void
 schnorr_selftest_one(const BIGNUM *grp_p, const BIGNUM *grp_q,
@@ -328,16 +565,17 @@ schnorr_selftest_one(const BIGNUM *grp_p, const BIGNUM *grp_q,
 
 	if (BN_mod_exp(g_x, grp_g, x, grp_p, bn_ctx) == -1)
 		fatal("%s: g_x", __func__);
-	if (schnorr_sign(grp_p, grp_q, grp_g, x, g_x, "junk", 4, &sig, &siglen))
+	if (schnorr_sign_buf(grp_p, grp_q, grp_g, x, g_x, "junk", 4,
+	    &sig, &siglen))
 		fatal("%s: schnorr_sign", __func__);
-	if (schnorr_verify(grp_p, grp_q, grp_g, g_x, "junk", 4,
+	if (schnorr_verify_buf(grp_p, grp_q, grp_g, g_x, "junk", 4,
 	    sig, siglen) != 1)
 		fatal("%s: verify fail", __func__);
-	if (schnorr_verify(grp_p, grp_q, grp_g, g_x, "JUNK", 4,
+	if (schnorr_verify_buf(grp_p, grp_q, grp_g, g_x, "JUNK", 4,
 	    sig, siglen) != 0)
 		fatal("%s: verify should have failed (bad ID)", __func__);
 	sig[4] ^= 1;
-	if (schnorr_verify(grp_p, grp_q, grp_g, g_x, "junk", 4,
+	if (schnorr_verify_buf(grp_p, grp_q, grp_g, g_x, "junk", 4,
 	    sig, siglen) != 0)
 		fatal("%s: verify should have failed (bit error)", __func__);
 	xfree(sig);
@@ -349,7 +587,7 @@ static void
 schnorr_selftest(void)
 {
 	BIGNUM *x;
-	struct jpake_group *grp;
+	struct modp_group *grp;
 	u_int i;
 	char *hh;
 
diff --git a/schnorr.h b/schnorr.h
new file mode 100644
index 00000000..9730b47c
--- /dev/null
+++ b/schnorr.h
@@ -0,0 +1,60 @@
+/* $OpenBSD: schnorr.h,v 1.1 2009/03/05 07:18:19 djm Exp $ */
+/*
+ * Copyright (c) 2009 Damien Miller.  All rights reserved.
+ *
+ * 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.
+ */
+
+#ifndef SCHNORR_H
+#define SCHNORR_H
+
+#include <sys/types.h>
+
+#include <openssl/bn.h>
+
+struct modp_group {
+	BIGNUM *p, *q, *g;
+};
+
+BIGNUM *bn_rand_range_gt_one(const BIGNUM *high);
+int hash_buffer(const u_char *, u_int, const EVP_MD *, u_char **, u_int *);
+void debug3_bn(const BIGNUM *, const char *, ...)
+    __attribute__((__nonnull__ (2)))
+    __attribute__((format(printf, 2, 3)));
+void debug3_buf(const u_char *, u_int, const char *, ...)
+    __attribute__((__nonnull__ (3)))
+    __attribute__((format(printf, 3, 4)));
+struct modp_group *modp_group_from_g_and_safe_p(const char *, const char *);
+void modp_group_free(struct modp_group *);
+
+/* Signature and verification functions */
+int
+schnorr_sign(const BIGNUM *grp_p, const BIGNUM *grp_q, const BIGNUM *grp_g,
+    const EVP_MD *evp_md, const BIGNUM *x, const BIGNUM *g_x,
+    const u_char *id, u_int idlen, BIGNUM **r_p, BIGNUM **e_p);
+int
+schnorr_sign_buf(const BIGNUM *grp_p, const BIGNUM *grp_q, const BIGNUM *grp_g,
+    const BIGNUM *x, const BIGNUM *g_x, const u_char *id, u_int idlen,
+    u_char **sig, u_int *siglen);
+int
+schnorr_verify(const BIGNUM *grp_p, const BIGNUM *grp_q, const BIGNUM *grp_g,
+    const EVP_MD *evp_md, const BIGNUM *g_x, const u_char *id, u_int idlen,
+    const BIGNUM *r, const BIGNUM *e);
+int
+schnorr_verify_buf(const BIGNUM *grp_p, const BIGNUM *grp_q,
+    const BIGNUM *grp_g,
+    const BIGNUM *g_x, const u_char *id, u_int idlen,
+    const u_char *sig, u_int siglen);
+
+#endif /* JPAKE_H */
+
diff --git a/sshconnect2.c b/sshconnect2.c
index a762eec3..260c6307 100644
--- a/sshconnect2.c
+++ b/sshconnect2.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: sshconnect2.c,v 1.170 2008/11/04 08:22:13 djm Exp $ */
+/* $OpenBSD: sshconnect2.c,v 1.171 2009/03/05 07:18:19 djm Exp $ */
 /*
  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
  * Copyright (c) 2008 Damien Miller.  All rights reserved.
@@ -68,6 +68,7 @@
 #include "msg.h"
 #include "pathnames.h"
 #include "uidswap.h"
+#include "schnorr.h"
 #include "jpake.h"
 
 #ifdef GSSAPI
-- 
2.45.1