X-Git-Url: https://git.openssl.org/gitweb/?p=openssl.git;a=blobdiff_plain;f=crypto%2Fdh%2Fdh_check.c;h=0acd7753e9c206692c46691e2a1676504a299f3b;hp=8da8dc839390184b801acfdd8353d5ff904a0a54;hb=1d97c8435171a7af575f73c526d79e1ef0ee5960;hpb=d02b48c63a58ea4367a0e905979f140b7d090f86

diff --git a/crypto/dh/dh_check.c b/crypto/dh/dh_check.c
index 8da8dc8393..0acd7753e9 100644
--- a/crypto/dh/dh_check.c
+++ b/crypto/dh/dh_check.c
@@ -1,5 +1,5 @@
 /* crypto/dh/dh_check.c */
-/* Copyright (C) 1995-1997 Eric Young (eay@cryptsoft.com)
+/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
  * This package is an SSL implementation written
@@ -58,11 +58,12 @@
 
 #include <stdio.h>
 #include "cryptlib.h"
-#include "bn.h"
-#include "dh.h"
+#include <openssl/bn.h>
+#include <openssl/dh.h>
 
-/* Check that p is a strong prime and
- * if g is 2, 3 or 5, check that is is a suitable generator
+/*-
+ * Check that p is a safe prime and
+ * if g is 2, 3 or 5, check that it is a suitable generator
  * where
  * for 2, p mod 24 == 11
  * for 3, p mod 12 == 5
@@ -70,31 +71,59 @@
  * should hold.
  */
 
-int DH_check(dh,ret)
-DH *dh;
-int *ret;
+int DH_check(const DH *dh, int *ret)
 	{
 	int ok=0;
 	BN_CTX *ctx=NULL;
 	BN_ULONG l;
-	BIGNUM *q=NULL;
+	BIGNUM *t1=NULL, *t2 = NULL;
 
 	*ret=0;
 	ctx=BN_CTX_new();
 	if (ctx == NULL) goto err;
-	q=BN_new();
-	if (q == NULL) goto err;
+	BN_CTX_start(ctx);
+	t1=BN_CTX_get(ctx);
+	if (t1 == NULL) goto err;
+	t2=BN_CTX_get(ctx);
+	if (t2 == NULL) goto err;
 
-	if (BN_is_word(dh->g,DH_GENERATOR_2))
+	if (dh->q)
+		{
+		if (BN_cmp(dh->g, BN_value_one()) <= 0)
+			*ret|=DH_NOT_SUITABLE_GENERATOR;
+		else if (BN_cmp(dh->g, dh->p) >= 0)
+			*ret|=DH_NOT_SUITABLE_GENERATOR;
+		else
+			{
+			/* Check g^q == 1 mod p */
+			if (!BN_mod_exp(t1, dh->g, dh->q, dh->p, ctx))
+				goto err;
+			if (!BN_is_one(t1))
+				*ret|=DH_NOT_SUITABLE_GENERATOR;
+			}
+		if (!BN_is_prime_ex(dh->q,BN_prime_checks,ctx,NULL))
+			*ret|=DH_CHECK_Q_NOT_PRIME;
+		/* Check p == 1 mod q  i.e. q divides p - 1 */
+		if (!BN_div(t1, t2, dh->p, dh->q, ctx))
+			goto err;
+		if (!BN_is_one(t2))
+			*ret|=DH_CHECK_INVALID_Q_VALUE;
+		if (dh->j && BN_cmp(dh->j, t1))
+			*ret|=DH_CHECK_INVALID_J_VALUE;
+			
+		}
+	else if (BN_is_word(dh->g,DH_GENERATOR_2))
 		{
 		l=BN_mod_word(dh->p,24);
 		if (l != 11) *ret|=DH_NOT_SUITABLE_GENERATOR;
 		}
-/*	else if (BN_is_word(dh->g,DH_GENERATOR_3))
+#if 0
+	else if (BN_is_word(dh->g,DH_GENERATOR_3))
 		{
 		l=BN_mod_word(dh->p,12);
 		if (l != 5) *ret|=DH_NOT_SUITABLE_GENERATOR;
-		}*/
+		}
+#endif
 	else if (BN_is_word(dh->g,DH_GENERATOR_5))
 		{
 		l=BN_mod_word(dh->p,10);
@@ -104,17 +133,42 @@ int *ret;
 	else
 		*ret|=DH_UNABLE_TO_CHECK_GENERATOR;
 
-	if (!BN_is_prime(dh->p,BN_prime_checks,NULL,ctx))
+	if (!BN_is_prime_ex(dh->p,BN_prime_checks,ctx,NULL))
 		*ret|=DH_CHECK_P_NOT_PRIME;
-	else
+	else if (!dh->q)
 		{
-		if (!BN_rshift1(q,dh->p)) goto err;
-		if (!BN_is_prime(q,BN_prime_checks,NULL,ctx))
-			*ret|=DH_CHECK_P_NOT_STRONG_PRIME;
+		if (!BN_rshift1(t1,dh->p)) goto err;
+		if (!BN_is_prime_ex(t1,BN_prime_checks,ctx,NULL))
+			*ret|=DH_CHECK_P_NOT_SAFE_PRIME;
 		}
 	ok=1;
 err:
-	if (ctx != NULL) BN_CTX_free(ctx);
+	if (ctx != NULL)
+		{
+		BN_CTX_end(ctx);
+		BN_CTX_free(ctx);
+		}
+	return(ok);
+	}
+
+int DH_check_pub_key(const DH *dh, const BIGNUM *pub_key, int *ret)
+	{
+	int ok=0;
+	BIGNUM *q=NULL;
+
+	*ret=0;
+	q=BN_new();
+	if (q == NULL) goto err;
+	BN_set_word(q,1);
+	if (BN_cmp(pub_key,q)<=0)
+		*ret|=DH_CHECK_PUBKEY_TOO_SMALL;
+	BN_copy(q,dh->p);
+	BN_sub_word(q,1);
+	if (BN_cmp(pub_key,q)>=0)
+		*ret|=DH_CHECK_PUBKEY_TOO_LARGE;
+
+	ok = 1;
+err:
 	if (q != NULL) BN_free(q);
 	return(ok);
 	}