- djm@cvs.openbsd.org 2006/03/19 02:23:26

[openssh.git] / dh.c

diff --git a/dh.c b/dh.c
index e691125e0a81dcb417618aefd9a0b42172f84cb2..a30b704fbc319ecc254919b481beabf120bda90f 100644 (file)
--- a/dh.c
+++ b/dh.c
@@ -23,14 +23,12 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: dh.c,v 1.20 2002/03/06 00:20:54 markus Exp $");
 
 #include "xmalloc.h"
 
 #include <openssl/bn.h>
 #include <openssl/dh.h>
 #include <openssl/evp.h>
-#include <openssl/err.h>
 
 #include "buffer.h"
 #include "cipher.h"
@@ -51,7 +49,7 @@ 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 */
@@ -92,6 +90,9 @@ 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:
@@ -106,15 +107,16 @@ 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;
@@ -141,8 +143,8 @@ 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;
@@ -167,7 +169,7 @@ 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)
@@ -177,29 +179,29 @@ 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 {
@@ -208,16 +210,14 @@ dh_gen_key(DH *dh, int need)
                if ((dh->priv_key = BN_new()) == NULL)
                        fatal("dh_gen_key: BN_new failed");
                /* generate a 2*need bits random private exponent */
-               if (!BN_rand(dh->priv_key, 2*need, 0, 0)) {
-                       int ecode = ERR_get_error();
-                       fatal("dh_gen_key: BN_rand failed: %s", ERR_error_string(ecode, NULL));
-               }
+               if (!BN_rand(dh->priv_key, 2*need, 0, 0))
+                       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");
@@ -272,6 +272,25 @@ 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
@@ -282,11 +301,9 @@ 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) */
 }