Add functions returning security bits.
[openssl.git] / crypto / dsa / dsa_gen.c
index a7d4783..9e3e57a 100644 (file)
 
 #ifndef OPENSSL_NO_SHA
 
+#define OPENSSL_FIPSAPI
+
 #include <stdio.h>
 #include "cryptlib.h"
 #include <openssl/evp.h>
 #include <openssl/bn.h>
 #include <openssl/rand.h>
 #include <openssl/sha.h>
+#ifdef OPENSSL_FIPS
+#include <openssl/fips.h>
+#include <openssl/fips_rand.h>
+#endif
+
 #include "dsa_locl.h"
 
 int DSA_generate_parameters_ex(DSA *ret, int bits,
@@ -105,12 +112,13 @@ int DSA_generate_parameters_ex(DSA *ret, int bits,
                        }
 
                return dsa_builtin_paramgen(ret, bits, qbits, evpmd,
-                               seed_in, seed_len, counter_ret, h_ret, cb);
+                       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;
@@ -126,6 +134,21 @@ int dsa_builtin_paramgen(DSA *ret, size_t bits, size_t qbits,
        BN_CTX *ctx=NULL;
        unsigned int h=2;
 
+#ifdef OPENSSL_FIPS
+       if(FIPS_selftest_failed())
+           {
+           FIPSerr(FIPS_F_DSA_BUILTIN_PARAMGEN, FIPS_R_FIPS_SELFTEST_FAILED);
+           goto err;
+           }
+
+       if (FIPS_module_mode() && !(ret->flags & DSA_FLAG_NON_FIPS_ALLOW) 
+                       && (bits < OPENSSL_DSA_FIPS_MIN_MODULUS_BITS))
+               {
+               DSAerr(DSA_F_DSA_BUILTIN_PARAMGEN, DSA_R_KEY_SIZE_TOO_SMALL);
+               goto err;
+               }
+#endif
+
        if (qsize != SHA_DIGEST_LENGTH && qsize != SHA224_DIGEST_LENGTH &&
            qsize != SHA256_DIGEST_LENGTH)
                /* invalid q size */
@@ -182,7 +205,8 @@ int dsa_builtin_paramgen(DSA *ret, size_t bits, size_t qbits,
 
                        if (!seed_len)
                                {
-                               RAND_pseudo_bytes(seed, qsize);
+                               if (RAND_pseudo_bytes(seed, qsize) < 0)
+                                       goto err;
                                seed_is_random = 1;
                                }
                        else
@@ -336,6 +360,8 @@ 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)
                {
@@ -345,4 +371,437 @@ err:
        if (mont != NULL) BN_MONT_CTX_free(mont);
        return ok;
        }
+
+#ifdef OPENSSL_FIPS
+
+/* Security strength of parameter values for (L,N): see FIPS186-3 4.2
+ * and SP800-131A
+ */
+
+
+static int fips_ffc_strength(size_t L, size_t N)
+       {
+       if (L >= 15360 && N >= 512)
+               return 256;
+       if (L >= 7680 && N >= 384)
+               return 192;
+       if (L >= 3072 && N >= 256)
+               return 128;
+       if (L >= 2048 && N >= 224)
+               return 112;
+       if (L >= 1024 && N >= 160)
+               return  80;
+       return 0;
+       }
+
+/* Valid DSA2 parameters from FIPS 186-3 */
+
+static int dsa2_valid_parameters(size_t L, size_t N)
+       {
+       if (L == 1024 && N == 160)
+               return 80;
+       if (L == 2048 && N == 224)
+               return 112;
+       if (L == 2048 && N == 256)
+               return 112;
+       if (L == 3072 && N == 256)
+               return 128;
+       return 0;
+       }
+
+int fips_check_dsa_prng(DSA *dsa, size_t L, size_t N)
+       {
+       int strength;
+       if (!FIPS_module_mode())
+               return 1;
+
+       if (dsa->flags & (DSA_FLAG_NON_FIPS_ALLOW|DSA_FLAG_FIPS_CHECKED))
+               return 1;
+
+       if (!L || !N)
+               {
+               L = BN_num_bits(dsa->p);
+               N = BN_num_bits(dsa->q);
+               }
+       if (!dsa2_valid_parameters(L, N))
+               {
+               FIPSerr(FIPS_F_FIPS_CHECK_DSA_PRNG, FIPS_R_INVALID_PARAMETERS);
+               return 0;
+               }
+
+       strength = fips_ffc_strength(L, N);
+
+       if (!strength)
+               {
+               FIPSerr(FIPS_F_FIPS_CHECK_DSA_PRNG,FIPS_R_KEY_TOO_SHORT);
+               return 0;
+               }
+
+       if (FIPS_rand_strength() >= strength)
+               return 1;
+
+       FIPSerr(FIPS_F_FIPS_CHECK_DSA_PRNG,FIPS_R_PRNG_STRENGTH_TOO_LOW);
+       return 0;
+
+       }
+#endif /* OPENSSL_FIPS */
+
+/* This is a parameter generation algorithm for the DSA2 algorithm as
+ * described in FIPS 186-3.
+ */
+
+int dsa_builtin_paramgen2(DSA *ret, size_t L, size_t N,
+       const EVP_MD *evpmd, const unsigned char *seed_in, size_t seed_len,
+       int idx, unsigned char *seed_out,
+       int *counter_ret, unsigned long *h_ret, BN_GENCB *cb)
+       {
+       int ok=-1;
+       unsigned char *seed = NULL, *seed_tmp = NULL;
+       unsigned char md[EVP_MAX_MD_SIZE];
+       int mdsize;
+       BIGNUM *r0,*W,*X,*c,*test;
+       BIGNUM *g=NULL,*q=NULL,*p=NULL;
+       BN_MONT_CTX *mont=NULL;
+       int i, k, n=0, m=0, qsize = N >> 3;
+       int counter=0;
+       int r=0;
+       BN_CTX *ctx=NULL;
+       EVP_MD_CTX mctx;
+       unsigned int h=2;
+
+       EVP_MD_CTX_init(&mctx);
+
+#ifdef OPENSSL_FIPS
+       if(FIPS_selftest_failed())
+           {
+           FIPSerr(FIPS_F_DSA_BUILTIN_PARAMGEN2,
+                   FIPS_R_FIPS_SELFTEST_FAILED);
+           goto err;
+           }
+
+       if (!fips_check_dsa_prng(ret, L, N))
+               goto err;
+#endif
+
+       if (evpmd == NULL)
+               {
+               if (N == 160)
+                       evpmd = EVP_sha1();
+               else if (N == 224)
+                       evpmd = EVP_sha224();
+               else
+                       evpmd = EVP_sha256();
+               }
+
+       mdsize = M_EVP_MD_size(evpmd);
+       /* If unverificable g generation only don't need seed */
+       if (!ret->p || !ret->q || idx >= 0)
+               {
+               if (seed_len == 0)
+                       seed_len = mdsize;
+
+               seed = OPENSSL_malloc(seed_len);
+
+               if (seed_out)
+                       seed_tmp = seed_out;
+               else
+                       seed_tmp = OPENSSL_malloc(seed_len);
+
+               if (!seed || !seed_tmp)
+                       goto err;
+
+               if (seed_in)
+                       memcpy(seed, seed_in, seed_len);
+
+               }
+
+       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);
+       X = BN_CTX_get(ctx);
+       c = BN_CTX_get(ctx);
+       test = BN_CTX_get(ctx);
+
+       /* if p, q already supplied generate g only */
+       if (ret->p && ret->q)
+               {
+               p = ret->p;
+               q = ret->q;
+               if (idx >= 0)
+                       memcpy(seed_tmp, seed, seed_len);
+               goto g_only;
+               }
+       else
+               {
+               p = BN_CTX_get(ctx);
+               q = BN_CTX_get(ctx);
+               }
+
+       if (!BN_lshift(test,BN_value_one(),L-1))
+               goto err;
+       for (;;)
+               {
+               for (;;) /* find q */
+                       {
+                       unsigned char *pmd;
+                       /* step 1 */
+                       if(!BN_GENCB_call(cb, 0, m++))
+                               goto err;
+
+                       if (!seed_in)
+                               {
+                               if (RAND_pseudo_bytes(seed, seed_len) < 0)
+                                       goto err;
+                               }
+                       /* step 2 */
+                       if (!EVP_Digest(seed, seed_len, md, NULL, evpmd, NULL))
+                               goto err;
+                       /* Take least significant bits of md */
+                       if (mdsize > qsize)
+                               pmd = md + mdsize - qsize;
+                       else
+                               pmd = md;
+
+                       if (mdsize < qsize)
+                               memset(md + mdsize, 0, qsize - mdsize);
+
+                       /* step 3 */
+                       pmd[0] |= 0x80;
+                       pmd[qsize-1] |= 0x01;
+                       if (!BN_bin2bn(pmd, qsize, q))
+                               goto err;
+
+                       /* step 4 */
+                       r = BN_is_prime_fasttest_ex(q, DSS_prime_checks, ctx,
+                                       seed_in ? 1 : 0, cb);
+                       if (r > 0)
+                               break;
+                       if (r != 0)
+                               goto err;
+                       /* Provided seed didn't produce a prime: error */
+                       if (seed_in)
+                               {
+                               ok = 0;
+                               DSAerr(DSA_F_DSA_BUILTIN_PARAMGEN2, DSA_R_Q_NOT_PRIME);
+                               goto err;
+                               }
+
+                       /* do a callback call */
+                       /* step 5 */
+                       }
+               /* Copy seed to seed_out before we mess with it */
+               if (seed_out)
+                       memcpy(seed_out, seed, seed_len);
+
+               if(!BN_GENCB_call(cb, 2, 0)) goto err;
+               if(!BN_GENCB_call(cb, 3, 0)) goto err;
+
+               /* step 6 */
+               counter=0;
+               /* "offset = 1" */
+
+               n=(L-1)/(mdsize << 3);
+
+               for (;;)
+                       {
+                       if ((counter != 0) && !BN_GENCB_call(cb, 0, counter))
+                               goto err;
+
+                       /* 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 = seed_len-1; i >= 0; i--)
+                                       {
+                                       seed[i]++;
+                                       if (seed[i] != 0)
+                                               break;
+                                       }
+
+                               if (!EVP_Digest(seed, seed_len, md ,NULL, evpmd,
+                                                                       NULL))
+                                       goto err;
+
+                               /* step 8 */
+                               if (!BN_bin2bn(md, mdsize, r0))
+                                       goto err;
+                               if (!BN_lshift(r0,r0,(mdsize << 3)*k)) goto err;
+                               if (!BN_add(W,W,r0)) goto err;
+                               }
+
+                       /* more of step 8 */
+                       if (!BN_mask_bits(W,L-1)) goto err;
+                       if (!BN_copy(X,W)) goto err;
+                       if (!BN_add(X,X,test)) goto err;
+
+                       /* step 9 */
+                       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,
+                                               ctx, 1, cb);
+                               if (r > 0)
+                                               goto end; /* found it */
+                               if (r != 0)
+                                       goto err;
+                               }
+
+                       /* step 13 */
+                       counter++;
+                       /* "offset = offset + n + 1" */
+
+                       /* step 14 */
+                       if (counter >= (int)(4 * L)) break;
+                       }
+               if (seed_in)
+                       {
+                       ok = 0;
+                       DSAerr(DSA_F_DSA_BUILTIN_PARAMGEN2, DSA_R_INVALID_PARAMETERS);
+                       goto err;
+                       }
+               }
+end:
+       if(!BN_GENCB_call(cb, 2, 1))
+               goto err;
+
+       g_only:
+
+       /* We now need to generate g */
+       /* Set r0=(p-1)/q */
+       if (!BN_sub(test,p,BN_value_one())) goto err;
+       if (!BN_div(r0,NULL,test,q,ctx)) goto err;
+
+       if (idx < 0)
+               {
+               if (!BN_set_word(test,h))
+                       goto err;
+               }
+       else
+               h = 1;
+       if (!BN_MONT_CTX_set(mont,p,ctx)) goto err;
+
+       for (;;)
+               {
+               __fips_constseg
+               static const unsigned char ggen[4] = {0x67,0x67,0x65,0x6e};
+               if (idx >= 0)
+                       {
+                       md[0] = idx & 0xff;
+                       md[1] = (h >> 8) & 0xff;
+                       md[2] = h & 0xff;
+                       if (!EVP_DigestInit_ex(&mctx, evpmd, NULL))
+                               goto err;
+                       if (!EVP_DigestUpdate(&mctx, seed_tmp, seed_len))
+                               goto err;
+                       if (!EVP_DigestUpdate(&mctx, ggen, sizeof(ggen)))
+                               goto err;
+                       if (!EVP_DigestUpdate(&mctx, md, 3))
+                               goto err;
+                       if (!EVP_DigestFinal_ex(&mctx, md, NULL))
+                               goto err;
+                       if (!BN_bin2bn(md, mdsize, test))
+                               goto err;
+                       }
+               /* g=test^r0%p */
+               if (!BN_mod_exp_mont(g,test,r0,p,ctx,mont)) goto err;
+               if (!BN_is_one(g)) break;
+               if (idx < 0 && !BN_add(test,test,BN_value_one())) goto err;
+               h++;
+               if ( idx >= 0 && h > 0xffff)
+                       goto err;
+               }
+
+       if(!BN_GENCB_call(cb, 3, 1))
+               goto err;
+
+       ok=1;
+err:
+       if (ok == 1)
+               {
+               if (p != ret->p)
+                       {
+                       if(ret->p) BN_free(ret->p);
+                       ret->p=BN_dup(p);
+                       }
+               if (q != ret->q)
+                       {
+                       if(ret->q) BN_free(ret->q);
+                       ret->q=BN_dup(q);
+                       }
+               if(ret->g) BN_free(ret->g);
+               ret->g=BN_dup(g);
+               if (ret->p == NULL || ret->q == NULL || ret->g == NULL)
+                       {
+                       ok=-1;
+                       goto err;
+                       }
+               if (counter_ret != NULL) *counter_ret=counter;
+               if (h_ret != NULL) *h_ret=h;
+               }
+       if (seed)
+               OPENSSL_free(seed);
+       if (seed_out != seed_tmp)
+               OPENSSL_free(seed_tmp);
+       if(ctx)
+               {
+               BN_CTX_end(ctx);
+               BN_CTX_free(ctx);
+               }
+       if (mont != NULL) BN_MONT_CTX_free(mont);
+       EVP_MD_CTX_cleanup(&mctx);
+       return ok;
+       }
+
+int dsa_paramgen_check_g(DSA *dsa)
+       {
+       BN_CTX *ctx;
+       BIGNUM *tmp;
+       BN_MONT_CTX *mont = NULL;
+       int rv = -1;
+       ctx = BN_CTX_new();
+       if (!ctx)
+               return -1;
+       BN_CTX_start(ctx);
+       if (BN_cmp(dsa->g, BN_value_one()) <= 0)
+               return 0;
+       if (BN_cmp(dsa->g, dsa->p) >= 0)
+               return 0;
+       tmp = BN_CTX_get(ctx);
+       if (!tmp)
+               goto err;
+       if ((mont=BN_MONT_CTX_new()) == NULL)
+               goto err;
+       if (!BN_MONT_CTX_set(mont,dsa->p,ctx))
+               goto err;
+       /* Work out g^q mod p */
+       if (!BN_mod_exp_mont(tmp,dsa->g,dsa->q, dsa->p, ctx, mont))
+               goto err;
+       if (!BN_cmp(tmp, BN_value_one()))
+               rv = 1;
+       else
+               rv = 0;
+       err:
+       BN_CTX_end(ctx);
+       if (mont)
+               BN_MONT_CTX_free(mont);
+       BN_CTX_free(ctx);
+       return rv;
+
+       }
+
 #endif