X-Git-Url: http://andersk.mit.edu/gitweb/openssh.git/blobdiff_plain/b775c6f29418e64c65f1136a58bf68596be841f8..4145cbfa4fe8d607918a66c8def052876cda5f50:/dh.c

diff --git a/dh.c b/dh.c
index a5d6f379..044d869f 100644
--- a/dh.c
+++ b/dh.c
@@ -23,7 +23,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: dh.c,v 1.18 2001/12/27 18:22:16 markus Exp $");
+RCSID("$OpenBSD: dh.c,v 1.31 2004/08/04 10:37:52 djm Exp $");
 
 #include "xmalloc.h"
 
@@ -50,7 +50,7 @@ parse_prime(int linenum, char *line, struct dhgroup *dhg)
 	/* Ignore leading whitespace */
 	if (*arg == '\0')
 		arg = strdelim(&cp);
-	if (!*arg || *arg == '#')
+	if (!arg || !*arg || *arg == '#')
 		return 0;
 
 	/* time */
@@ -91,11 +91,14 @@ parse_prime(int linenum, char *line, struct dhgroup *dhg)
 	if (BN_num_bits(dhg->p) != dhg->size)
 		goto failclean;
 
+	if (BN_is_zero(dhg->g) || BN_is_one(dhg->g))
+		goto failclean;
+
 	return (1);
 
  failclean:
-	BN_free(dhg->g);
-	BN_free(dhg->p);
+	BN_clear_free(dhg->g);
+	BN_clear_free(dhg->p);
  fail:
 	error("Bad prime description in line %d", linenum);
 	return (0);
@@ -105,15 +108,16 @@ DH *
 choose_dh(int min, int wantbits, int max)
 {
 	FILE *f;
-	char line[2048];
+	char line[4096];
 	int best, bestcount, which;
 	int linenum;
 	struct dhgroup dhg;
 
 	if ((f = fopen(_PATH_DH_MODULI, "r")) == NULL &&
 	    (f = fopen(_PATH_DH_PRIMES, "r")) == NULL) {
-		log("WARNING: %s does not exist, using old modulus", _PATH_DH_MODULI);
-		return (dh_new_group1());
+		logit("WARNING: %s does not exist, using fixed modulus",
+		    _PATH_DH_MODULI);
+		return (dh_new_group14());
 	}
 
 	linenum = 0;
@@ -122,8 +126,8 @@ choose_dh(int min, int wantbits, int max)
 		linenum++;
 		if (!parse_prime(linenum, line, &dhg))
 			continue;
-		BN_free(dhg.g);
-		BN_free(dhg.p);
+		BN_clear_free(dhg.g);
+		BN_clear_free(dhg.p);
 
 		if (dhg.size > max || dhg.size < min)
 			continue;
@@ -140,8 +144,8 @@ choose_dh(int min, int wantbits, int max)
 
 	if (bestcount == 0) {
 		fclose(f);
-		log("WARNING: no suitable primes in %s", _PATH_DH_PRIMES);
-		return (NULL);
+		logit("WARNING: no suitable primes in %s", _PATH_DH_PRIMES);
+		return (dh_new_group14());
 	}
 
 	linenum = 0;
@@ -152,8 +156,8 @@ choose_dh(int min, int wantbits, int max)
 		if ((dhg.size > max || dhg.size < min) ||
 		    dhg.size != best ||
 		    linenum++ != which) {
-			BN_free(dhg.g);
-			BN_free(dhg.p);
+			BN_clear_free(dhg.g);
+			BN_clear_free(dhg.p);
 			continue;
 		}
 		break;
@@ -166,7 +170,7 @@ choose_dh(int min, int wantbits, int max)
 	return (dh_new_group(dhg.g, dhg.p));
 }
 
-/* diffie-hellman-group1-sha1 */
+/* diffie-hellman-groupN-sha1 */
 
 int
 dh_pub_is_valid(DH *dh, BIGNUM *dh_pub)
@@ -176,34 +180,34 @@ dh_pub_is_valid(DH *dh, BIGNUM *dh_pub)
 	int bits_set = 0;
 
 	if (dh_pub->neg) {
-		log("invalid public DH value: negativ");
+		logit("invalid public DH value: negativ");
 		return 0;
 	}
 	for (i = 0; i <= n; i++)
 		if (BN_is_bit_set(dh_pub, i))
 			bits_set++;
-	debug("bits set: %d/%d", bits_set, BN_num_bits(dh->p));
+	debug2("bits set: %d/%d", bits_set, BN_num_bits(dh->p));
 
 	/* if g==2 and bits_set==1 then computing log_g(dh_pub) is trivial */
 	if (bits_set > 1 && (BN_cmp(dh_pub, dh->p) == -1))
 		return 1;
-	log("invalid public DH value (%d/%d)", bits_set, BN_num_bits(dh->p));
+	logit("invalid public DH value (%d/%d)", bits_set, BN_num_bits(dh->p));
 	return 0;
 }
 
 void
 dh_gen_key(DH *dh, int need)
 {
-	int i, bits_set = 0, tries = 0;
+	int i, bits_set, tries = 0;
 
 	if (dh->p == NULL)
 		fatal("dh_gen_key: dh->p == NULL");
-	if (2*need >= BN_num_bits(dh->p))
+	if (need > INT_MAX / 2 || 2 * need >= BN_num_bits(dh->p))
 		fatal("dh_gen_key: group too small: %d (2*need %d)",
 		    BN_num_bits(dh->p), 2*need);
 	do {
 		if (dh->priv_key != NULL)
-			BN_free(dh->priv_key);
+			BN_clear_free(dh->priv_key);
 		if ((dh->priv_key = BN_new()) == NULL)
 			fatal("dh_gen_key: BN_new failed");
 		/* generate a 2*need bits random private exponent */
@@ -211,10 +215,10 @@ dh_gen_key(DH *dh, int need)
 			fatal("dh_gen_key: BN_rand failed");
 		if (DH_generate_key(dh) == 0)
 			fatal("DH_generate_key");
-		for (i = 0; i <= BN_num_bits(dh->priv_key); i++)
+		for (i = 0, bits_set = 0; i <= BN_num_bits(dh->priv_key); i++)
 			if (BN_is_bit_set(dh->priv_key, i))
 				bits_set++;
-		debug("dh_gen_key: priv key bits set: %d/%d",
+		debug2("dh_gen_key: priv key bits set: %d/%d",
 		    bits_set, BN_num_bits(dh->priv_key));
 		if (tries++ > 10)
 			fatal("dh_gen_key: too many bad keys: giving up");
@@ -269,6 +273,25 @@ dh_new_group1(void)
 	return (dh_new_group_asc(gen, group1));
 }
 
+DH *
+dh_new_group14(void)
+{
+	static char *gen = "2", *group14 =
+	    "FFFFFFFF" "FFFFFFFF" "C90FDAA2" "2168C234" "C4C6628B" "80DC1CD1"
+	    "29024E08" "8A67CC74" "020BBEA6" "3B139B22" "514A0879" "8E3404DD"
+	    "EF9519B3" "CD3A431B" "302B0A6D" "F25F1437" "4FE1356D" "6D51C245"
+	    "E485B576" "625E7EC6" "F44C42E9" "A637ED6B" "0BFF5CB6" "F406B7ED"
+	    "EE386BFB" "5A899FA5" "AE9F2411" "7C4B1FE6" "49286651" "ECE45B3D"
+	    "C2007CB8" "A163BF05" "98DA4836" "1C55D39A" "69163FA8" "FD24CF5F"
+	    "83655D23" "DCA3AD96" "1C62F356" "208552BB" "9ED52907" "7096966D"
+	    "670C354E" "4ABC9804" "F1746C08" "CA18217C" "32905E46" "2E36CE3B"
+	    "E39E772C" "180E8603" "9B2783A2" "EC07A28F" "B5C55DF0" "6F4C52C9"
+	    "DE2BCBF6" "95581718" "3995497C" "EA956AE5" "15D22618" "98FA0510"
+	    "15728E5A" "8AACAA68" "FFFFFFFF" "FFFFFFFF";
+
+	return (dh_new_group_asc(gen, group14));
+}
+
 /*
  * Estimates the group order for a Diffie-Hellman group that has an
  * attack complexity approximately the same as O(2**bits).  Estimate
@@ -279,11 +302,9 @@ int
 dh_estimate(int bits)
 {
 
-	if (bits < 64)
-		return (512);	/* O(2**63) */
-	if (bits < 128)
+	if (bits <= 128)
 		return (1024);	/* O(2**86) */
-	if (bits < 192)
+	if (bits <= 192)
 		return (2048);	/* O(2**116) */
 	return (4096);		/* O(2**156) */
 }