Tiny changes to previous patch (the log message was meant to be
[openssl.git] / crypto / dsa / dsa_gen.c
index c2661c1..710a4fa 100644 (file)
 #undef GENUINE_DSA
 
 #ifdef GENUINE_DSA
+/* Parameter generation follows the original release of FIPS PUB 186,
+ * Appendix 2.2 (i.e. use SHA as defined in FIPS PUB 180) */
 #define HASH    SHA
 #else
+/* Parameter generation follows the updated Appendix 2.2 for FIPS PUB 186,
+ * also Appendix 2.2 of FIPS PUB 186-1 (i.e. use SHA as defined in
+ * FIPS PUB 180-1) */
 #define HASH    SHA1
 #endif 
 
 #ifndef NO_SHA
+
 #include <stdio.h>
 #include <time.h>
 #include "cryptlib.h"
@@ -74,8 +80,8 @@
 #include <openssl/rand.h>
 
 DSA *DSA_generate_parameters(int bits, unsigned char *seed_in, int seed_len,
-            int *counter_ret, unsigned long *h_ret, void (*callback)(),
-            char *cb_arg)
+               int *counter_ret, unsigned long *h_ret, void (*callback)(),
+               void *cb_arg)
        {
        int ok=0;
        unsigned char seed[SHA_DIGEST_LENGTH];
@@ -86,18 +92,26 @@ DSA *DSA_generate_parameters(int bits, unsigned char *seed_in, int seed_len,
        BN_MONT_CTX *mont=NULL;
        int k,n=0,i,b,m=0;
        int counter=0;
-       BN_CTX *ctx=NULL,*ctx2=NULL;
+       int r=0;
+       BN_CTX *ctx=NULL,*ctx2=NULL,*ctx3=NULL,*ctx4=NULL;
        unsigned int h=2;
        DSA *ret=NULL;
 
        if (bits < 512) bits=512;
        bits=(bits+63)/64*64;
 
+       if (seed_len < 20)
+               seed_in = NULL; /* seed buffer too small -- ignore */
+       if (seed_len > 20) 
+               seed_len = 20; /* App. 2.2 of FIPS PUB 186 allows larger SEED,
+                               * but our internal buffers are restricted to 160 bits*/
        if ((seed_in != NULL) && (seed_len == 20))
                memcpy(seed,seed_in,seed_len);
 
        if ((ctx=BN_CTX_new()) == NULL) goto err;
        if ((ctx2=BN_CTX_new()) == NULL) goto err;
+       if ((ctx3=BN_CTX_new()) == NULL) goto err;
+       if ((ctx4=BN_CTX_new()) == NULL) goto err;
        if ((ret=DSA_new()) == NULL) goto err;
 
        if ((mont=BN_MONT_CTX_new()) == NULL) goto err;
@@ -115,18 +129,26 @@ DSA *DSA_generate_parameters(int bits, unsigned char *seed_in, int seed_len,
 
        for (;;)
                {
-               for (;;)
+               for (;;) /* find q */
                        {
+                       int seed_is_random;
+
                        /* step 1 */
                        if (callback != NULL) callback(0,m++,cb_arg);
 
                        if (!seed_len)
-                               RAND_bytes(seed,SHA_DIGEST_LENGTH);
+                               {
+                               RAND_pseudo_bytes(seed,SHA_DIGEST_LENGTH);
+                               seed_is_random = 1;
+                               }
                        else
-                               seed_len=0;
-
+                               {
+                               seed_is_random = 0;
+                               seed_len=0; /* use random seed if 'seed_in' turns out to be bad*/
+                               }
                        memcpy(buf,seed,SHA_DIGEST_LENGTH);
                        memcpy(buf2,seed,SHA_DIGEST_LENGTH);
+                       /* precompute "SEED + 1" for step 7: */
                        for (i=SHA_DIGEST_LENGTH-1; i >= 0; i--)
                                {
                                buf[i]++;
@@ -142,10 +164,15 @@ DSA *DSA_generate_parameters(int bits, unsigned char *seed_in, int seed_len,
                        /* step 3 */
                        md[0]|=0x80;
                        md[SHA_DIGEST_LENGTH-1]|=0x01;
-                       if (!BN_bin2bn(md,SHA_DIGEST_LENGTH,q)) abort();
+                       if (!BN_bin2bn(md,SHA_DIGEST_LENGTH,q)) goto err;
 
                        /* step 4 */
-                       if (DSA_is_prime(q,callback,cb_arg) > 0) break;
+                       r = BN_is_prime_fasttest(q, DSS_prime_checks, callback, ctx3, ctx4, cb_arg, seed_is_random);
+                       if (r > 0)
+                                       break;
+                       if (r != 0)
+                                       goto err;
+
                        /* do a callback call */
                        /* step 5 */
                        }
@@ -155,16 +182,22 @@ DSA *DSA_generate_parameters(int bits, unsigned char *seed_in, int seed_len,
 
                /* step 6 */
                counter=0;
+               /* "offset = 2" */
 
                n=(bits-1)/160;
                b=(bits-1)-n*160;
 
                for (;;)
                        {
+                       if (callback != NULL && counter != 0)
+                               callback(0,counter,cb_arg);
+
                        /* step 7 */
                        BN_zero(W);
+                       /* now 'buf' contains "SEED + offset - 1" */
                        for (k=0; k<=n; k++)
                                {
+                               /* obtain "SEED + offset + k" by incrementing: */
                                for (i=SHA_DIGEST_LENGTH-1; i >= 0; i--)
                                        {
                                        buf[i]++;
@@ -174,7 +207,8 @@ DSA *DSA_generate_parameters(int bits, unsigned char *seed_in, int seed_len,
                                HASH(buf,SHA_DIGEST_LENGTH,md);
 
                                /* step 8 */
-                               if (!BN_bin2bn(md,SHA_DIGEST_LENGTH,r0)) abort();
+                               if (!BN_bin2bn(md,SHA_DIGEST_LENGTH,r0))
+                                       goto err;
                                BN_lshift(r0,r0,160*k);
                                BN_add(W,W,r0);
                                }
@@ -194,26 +228,28 @@ DSA *DSA_generate_parameters(int bits, unsigned char *seed_in, int seed_len,
                        if (BN_cmp(p,test) >= 0)
                                {
                                /* step 11 */
-                               if (DSA_is_prime(p,callback,cb_arg) > 0)
-                                       goto end;
+                               r = BN_is_prime_fasttest(p, DSS_prime_checks, callback, ctx3, ctx4, cb_arg, 1);
+                               if (r > 0)
+                                               goto end; /* found it */
+                               if (r != 0)
+                                       goto err;
                                }
 
                        /* step 13 */
                        counter++;
+                       /* "offset = offset + n + 1" */
 
                        /* step 14 */
                        if (counter >= 4096) break;
-
-                       if (callback != NULL) callback(0,counter,cb_arg);
                        }
                }
 end:
        if (callback != NULL) callback(2,1,cb_arg);
 
-       /* We now need to gernerate g */
+       /* We now need to generate g */
        /* Set r0=(p-1)/q */
-        BN_sub(test,p,BN_value_one());
-        BN_div(r0,NULL,test,q,ctx);
+       BN_sub(test,p,BN_value_one());
+       BN_div(r0,NULL,test,q,ctx);
 
        BN_set_word(test,h);
        BN_MONT_CTX_set(mont,p,ctx);
@@ -245,88 +281,10 @@ err:
                if (h_ret != NULL) *h_ret=h;
                }
        if (ctx != NULL) BN_CTX_free(ctx);
-       if (ctx != NULL) BN_CTX_free(ctx2);
+       if (ctx2 != NULL) BN_CTX_free(ctx2);
+       if (ctx3 != NULL) BN_CTX_free(ctx3);
+       if (ctx4 != NULL) BN_CTX_free(ctx4);
        if (mont != NULL) BN_MONT_CTX_free(mont);
        return(ok?ret:NULL);
        }
-
-int DSA_is_prime(BIGNUM *w, void (*callback)(), char *cb_arg)
-       {
-       int ok= -1,j,i,n;
-       BN_CTX *ctx=NULL,*ctx2=NULL;
-       BIGNUM *w_1,*b,*m,*z,*tmp,*mont_1;
-       int a;
-       BN_MONT_CTX *mont=NULL;
-
-       if (!BN_is_bit_set(w,0)) return(0);
-
-       if ((ctx=BN_CTX_new()) == NULL) goto err;
-       if ((ctx2=BN_CTX_new()) == NULL) goto err;
-       if ((mont=BN_MONT_CTX_new()) == NULL) goto err;
-
-       m=   &(ctx2->bn[2]);
-       b=   &(ctx2->bn[3]);
-       z=   &(ctx2->bn[4]);
-       w_1= &(ctx2->bn[5]);
-       tmp= &(ctx2->bn[6]);
-       mont_1= &(ctx2->bn[7]);
-
-       /* step 1 */
-       n=50;
-
-       /* step 2 */
-       if (!BN_sub(w_1,w,BN_value_one())) goto err;
-       for (a=1; !BN_is_bit_set(w_1,a); a++)
-               ;
-       if (!BN_rshift(m,w_1,a)) goto err;
-
-       BN_MONT_CTX_set(mont,w,ctx);
-       BN_to_montgomery(mont_1,BN_value_one(),mont,ctx);
-       BN_to_montgomery(w_1,w_1,mont,ctx);
-       for (i=1; i < n; i++)
-               {
-               /* step 3 */
-               BN_rand(b,BN_num_bits(w)-2/*-1*/,0,0);
-               /* BN_set_word(b,0x10001L); */
-
-               /* step 4 */
-               j=0;
-               if (!BN_mod_exp_mont(z,b,m,w,ctx,mont)) goto err;
-
-               if (!BN_to_montgomery(z,z,mont,ctx)) goto err;
-
-               /* step 5 */
-               for (;;)
-                       {
-                       if (((j == 0) && (BN_cmp(z,mont_1) == 0)) ||
-                               (BN_cmp(z,w_1) == 0))
-                               break;
-
-                       /* step 6 */
-                       if ((j > 0) && (BN_cmp(z,mont_1) == 0))
-                               {
-                               ok=0;
-                               goto err;
-                               }
-
-                       j++;
-                       if (j >= a)
-                               {
-                               ok=0;
-                               goto err;
-                               }
-
-                       if (!BN_mod_mul_montgomery(z,z,z,mont,ctx)) goto err;
-                       if (callback != NULL) callback(1,j,cb_arg);
-                       }
-               }
-
-       ok=1;
-err:
-       if (ok == -1) DSAerr(DSA_F_DSA_IS_PRIME,ERR_R_BN_LIB);
-       BN_CTX_free(ctx);
-       BN_CTX_free(ctx2);
-       
-       return(ok);
-       }
 #endif