X-Git-Url: https://git.openssl.org/gitweb/?p=openssl.git;a=blobdiff_plain;f=crypto%2Fdsa%2Fdsa_gen.c;h=e6a545201614609706a1cdd604ad9735a709659d;hp=ca2c8670897079e526a9029eef97acb00d575995;hb=198ce9a611b451656e7c984e16452e285597a015;hpb=e9224c717711eefb30038c9b37c69795dda93c9a

diff --git a/crypto/dsa/dsa_gen.c b/crypto/dsa/dsa_gen.c
index ca2c867089..e6a5452016 100644
--- a/crypto/dsa/dsa_gen.c
+++ b/crypto/dsa/dsa_gen.c
@@ -69,62 +69,107 @@
 #define HASH    EVP_sha1()
 #endif 
 
+#include <openssl/opensslconf.h> /* To see if OPENSSL_NO_SHA is defined */
+
 #ifndef OPENSSL_NO_SHA
 
 #include <stdio.h>
-#include <time.h>
 #include "cryptlib.h"
 #include <openssl/evp.h>
 #include <openssl/bn.h>
-#include <openssl/dsa.h>
 #include <openssl/rand.h>
 #include <openssl/sha.h>
+#include "dsa_locl.h"
 
 int DSA_generate_parameters_ex(DSA *ret, int bits,
-		unsigned char *seed_in, int seed_len,
+		const unsigned char *seed_in, int seed_len,
 		int *counter_ret, unsigned long *h_ret, BN_GENCB *cb)
 	{
+	if(ret->meth->dsa_paramgen)
+		return ret->meth->dsa_paramgen(ret, bits, seed_in, seed_len,
+				counter_ret, h_ret, cb);
+	else
+		{
+		const EVP_MD *evpmd;
+		size_t qbits = bits >= 2048 ? 256 : 160;
+
+		if (bits >= 2048)
+			{
+			qbits = 256;
+			evpmd = EVP_sha256();
+			}
+		else
+			{
+			qbits = 160;
+			evpmd = EVP_sha1();
+			}
+
+		return dsa_builtin_paramgen(ret, bits, qbits, evpmd,
+			seed_in, seed_len, NULL, counter_ret, h_ret, cb);
+		}
+	}
+
+int dsa_builtin_paramgen(DSA *ret, size_t bits, size_t qbits,
+	const EVP_MD *evpmd, const unsigned char *seed_in, size_t seed_len,
+	unsigned char *seed_out,
+	int *counter_ret, unsigned long *h_ret, BN_GENCB *cb)
+	{
 	int ok=0;
-	unsigned char seed[SHA_DIGEST_LENGTH];
-	unsigned char md[SHA_DIGEST_LENGTH];
-	unsigned char buf[SHA_DIGEST_LENGTH],buf2[SHA_DIGEST_LENGTH];
+	unsigned char seed[SHA256_DIGEST_LENGTH];
+	unsigned char md[SHA256_DIGEST_LENGTH];
+	unsigned char buf[SHA256_DIGEST_LENGTH],buf2[SHA256_DIGEST_LENGTH];
 	BIGNUM *r0,*W,*X,*c,*test;
 	BIGNUM *g=NULL,*q=NULL,*p=NULL;
 	BN_MONT_CTX *mont=NULL;
-	int k,n=0,i,b,m=0;
+	int i, k, n=0, m=0, qsize = qbits >> 3;
 	int counter=0;
 	int r=0;
-	BN_CTX *ctx=NULL,*ctx2=NULL,*ctx3=NULL;
+	BN_CTX *ctx=NULL;
 	unsigned int h=2;
 
-	if (bits < 512) bits=512;
-	bits=(bits+63)/64*64;
+	if (qsize != SHA_DIGEST_LENGTH && qsize != SHA224_DIGEST_LENGTH &&
+	    qsize != SHA256_DIGEST_LENGTH)
+		/* invalid q size */
+		return 0;
 
-	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 (evpmd == NULL)
+		/* use SHA1 as default */
+		evpmd = EVP_sha1();
 
-	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 (bits < 512)
+		bits = 512;
 
-	if ((mont=BN_MONT_CTX_new()) == NULL) goto err;
+	bits = (bits+63)/64*64;
 
-	BN_CTX_start(ctx2);
-	r0 = BN_CTX_get(ctx2);
-	g = BN_CTX_get(ctx2);
-	W = BN_CTX_get(ctx2);
-	q = BN_CTX_get(ctx2);
-	X = BN_CTX_get(ctx2);
-	c = BN_CTX_get(ctx2);
-	p = BN_CTX_get(ctx2);
-	test = BN_CTX_get(ctx2);
+	/* NB: seed_len == 0 is special case: copy generated seed to
+ 	 * seed_in if it is not NULL.
+ 	 */
+	if (seed_len && (seed_len < (size_t)qsize))
+		seed_in = NULL;		/* seed buffer too small -- ignore */
+	if (seed_len > (size_t)qsize) 
+		seed_len = qsize;	/* App. 2.2 of FIPS PUB 186 allows larger SEED,
+					 * but our internal buffers are restricted to 160 bits*/
+	if (seed_in != NULL)
+		memcpy(seed, seed_in, seed_len);
 
-	BN_lshift(test,BN_value_one(),bits-1);
+	if ((ctx=BN_CTX_new()) == NULL)
+		goto err;
+
+	if ((mont=BN_MONT_CTX_new()) == NULL)
+		goto err;
+
+	BN_CTX_start(ctx);
+	r0 = BN_CTX_get(ctx);
+	g = BN_CTX_get(ctx);
+	W = BN_CTX_get(ctx);
+	q = BN_CTX_get(ctx);
+	X = BN_CTX_get(ctx);
+	c = BN_CTX_get(ctx);
+	p = BN_CTX_get(ctx);
+	test = BN_CTX_get(ctx);
+
+	if (!BN_lshift(test,BN_value_one(),bits-1))
+		goto err;
 
 	for (;;)
 		{
@@ -138,7 +183,7 @@ int DSA_generate_parameters_ex(DSA *ret, int bits,
 
 			if (!seed_len)
 				{
-				RAND_pseudo_bytes(seed,SHA_DIGEST_LENGTH);
+				RAND_pseudo_bytes(seed, qsize);
 				seed_is_random = 1;
 				}
 			else
@@ -146,28 +191,32 @@ int DSA_generate_parameters_ex(DSA *ret, int bits,
 				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);
+			memcpy(buf , seed, qsize);
+			memcpy(buf2, seed, qsize);
 			/* precompute "SEED + 1" for step 7: */
-			for (i=SHA_DIGEST_LENGTH-1; i >= 0; i--)
+			for (i = qsize-1; i >= 0; i--)
 				{
 				buf[i]++;
-				if (buf[i] != 0) break;
+				if (buf[i] != 0)
+					break;
 				}
 
 			/* step 2 */
-			EVP_Digest(seed,SHA_DIGEST_LENGTH,md,NULL,HASH, NULL);
-			EVP_Digest(buf,SHA_DIGEST_LENGTH,buf2,NULL,HASH, NULL);
-			for (i=0; i<SHA_DIGEST_LENGTH; i++)
+			if (!EVP_Digest(seed, qsize, md,   NULL, evpmd, NULL))
+				goto err;
+			if (!EVP_Digest(buf,  qsize, buf2, NULL, evpmd, NULL))
+				goto err;
+			for (i = 0; i < qsize; i++)
 				md[i]^=buf2[i];
 
 			/* step 3 */
-			md[0]|=0x80;
-			md[SHA_DIGEST_LENGTH-1]|=0x01;
-			if (!BN_bin2bn(md,SHA_DIGEST_LENGTH,q)) goto err;
+			md[0] |= 0x80;
+			md[qsize-1] |= 0x01;
+			if (!BN_bin2bn(md, qsize, q))
+				goto err;
 
 			/* step 4 */
-			r = BN_is_prime_fasttest_ex(q, DSS_prime_checks, ctx3,
+			r = BN_is_prime_fasttest_ex(q, DSS_prime_checks, ctx,
 					seed_is_random, cb);
 			if (r > 0)
 				break;
@@ -186,7 +235,6 @@ int DSA_generate_parameters_ex(DSA *ret, int bits,
 		/* "offset = 2" */
 
 		n=(bits-1)/160;
-		b=(bits-1)-n*160;
 
 		for (;;)
 			{
@@ -199,38 +247,41 @@ int DSA_generate_parameters_ex(DSA *ret, int bits,
 			for (k=0; k<=n; k++)
 				{
 				/* obtain "SEED + offset + k" by incrementing: */
-				for (i=SHA_DIGEST_LENGTH-1; i >= 0; i--)
+				for (i = qsize-1; i >= 0; i--)
 					{
 					buf[i]++;
-					if (buf[i] != 0) break;
+					if (buf[i] != 0)
+						break;
 					}
 
-				EVP_Digest(buf,SHA_DIGEST_LENGTH,md,NULL,HASH, NULL);
+				if (!EVP_Digest(buf, qsize, md ,NULL, evpmd,
+									NULL))
+					goto err;
 
 				/* step 8 */
-				if (!BN_bin2bn(md,SHA_DIGEST_LENGTH,r0))
+				if (!BN_bin2bn(md, qsize, r0))
 					goto err;
-				BN_lshift(r0,r0,160*k);
-				BN_add(W,W,r0);
+				if (!BN_lshift(r0,r0,(qsize << 3)*k)) goto err;
+				if (!BN_add(W,W,r0)) goto err;
 				}
 
 			/* more of step 8 */
-			BN_mask_bits(W,bits-1);
-			BN_copy(X,W); /* this should be ok */
-			BN_add(X,X,test); /* this should be ok */
+			if (!BN_mask_bits(W,bits-1)) goto err;
+			if (!BN_copy(X,W)) goto err;
+			if (!BN_add(X,X,test)) goto err;
 
 			/* step 9 */
-			BN_lshift1(r0,q);
-			BN_mod(c,X,r0,ctx);
-			BN_sub(r0,c,BN_value_one());
-			BN_sub(p,X,r0);
+			if (!BN_lshift1(r0,q)) goto err;
+			if (!BN_mod(c,X,r0,ctx)) goto err;
+			if (!BN_sub(r0,c,BN_value_one())) goto err;
+			if (!BN_sub(p,X,r0)) goto err;
 
 			/* step 10 */
 			if (BN_cmp(p,test) >= 0)
 				{
 				/* step 11 */
 				r = BN_is_prime_fasttest_ex(p, DSS_prime_checks,
-						ctx3, 1, cb);
+						ctx, 1, cb);
 				if (r > 0)
 						goto end; /* found it */
 				if (r != 0)
@@ -251,18 +302,18 @@ end:
 
 	/* 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);
+	if (!BN_sub(test,p,BN_value_one())) goto err;
+	if (!BN_div(r0,NULL,test,q,ctx)) goto err;
 
-	BN_set_word(test,h);
-	BN_MONT_CTX_set(mont,p,ctx);
+	if (!BN_set_word(test,h)) goto err;
+	if (!BN_MONT_CTX_set(mont,p,ctx)) goto err;
 
 	for (;;)
 		{
 		/* g=test^r0%p */
-		BN_mod_exp_mont(g,test,r0,p,ctx,mont);
+		if (!BN_mod_exp_mont(g,test,r0,p,ctx,mont)) goto err;
 		if (!BN_is_one(g)) break;
-		BN_add(test,test,BN_value_one());
+		if (!BN_add(test,test,BN_value_one())) goto err;
 		h++;
 		}
 
@@ -279,17 +330,21 @@ err:
 		ret->p=BN_dup(p);
 		ret->q=BN_dup(q);
 		ret->g=BN_dup(g);
-		if ((m > 1) && (seed_in != NULL)) memcpy(seed_in,seed,20);
+		if (ret->p == NULL || ret->q == NULL || ret->g == NULL)
+			{
+			ok=0;
+			goto err;
+			}
 		if (counter_ret != NULL) *counter_ret=counter;
 		if (h_ret != NULL) *h_ret=h;
+		if (seed_out)
+			memcpy(seed_out, seed, qsize);
 		}
-	if (ctx != NULL) BN_CTX_free(ctx);
-	if (ctx2 != NULL)
+	if(ctx)
 		{
-		BN_CTX_end(ctx2);
-		BN_CTX_free(ctx2);
+		BN_CTX_end(ctx);
+		BN_CTX_free(ctx);
 		}
-	if (ctx3 != NULL) BN_CTX_free(ctx3);
 	if (mont != NULL) BN_MONT_CTX_free(mont);
 	return ok;
 	}