X-Git-Url: https://git.openssl.org/gitweb/?p=openssl.git;a=blobdiff_plain;f=crypto%2Fdsa%2Fdsa_ossl.c;h=3fd8a35613d32dce4d252a6c65986df615210fe7;hp=1967290bafb01774f29ac400e346f9f830077922;hb=0ebfcc8f92736c900bae4066040b67f6e5db8edb;hpb=35ed8cb8b6655606c2be31d44be942f6724ba405;ds=sidebyside diff --git a/crypto/dsa/dsa_ossl.c b/crypto/dsa/dsa_ossl.c index 1967290baf..3fd8a35613 100644 --- a/crypto/dsa/dsa_ossl.c +++ b/crypto/dsa/dsa_ossl.c @@ -64,7 +64,6 @@ #include #include #include -#include static DSA_SIG *dsa_do_sign(const unsigned char *dgst, int dlen, DSA *dsa); static int dsa_sign_setup(DSA *dsa, BN_CTX *ctx_in, BIGNUM **kinvp, BIGNUM **rp); @@ -72,26 +71,57 @@ static int dsa_do_verify(const unsigned char *dgst, int dgst_len, DSA_SIG *sig, DSA *dsa); static int dsa_init(DSA *dsa); static int dsa_finish(DSA *dsa); -static int dsa_mod_exp(DSA *dsa, BIGNUM *rr, BIGNUM *a1, BIGNUM *p1, - BIGNUM *a2, BIGNUM *p2, BIGNUM *m, BN_CTX *ctx, - BN_MONT_CTX *in_mont); -static int dsa_bn_mod_exp(DSA *dsa, BIGNUM *r, BIGNUM *a, const BIGNUM *p, - const BIGNUM *m, BN_CTX *ctx, - BN_MONT_CTX *m_ctx); static DSA_METHOD openssl_dsa_meth = { "OpenSSL DSA method", dsa_do_sign, dsa_sign_setup, dsa_do_verify, -dsa_mod_exp, -dsa_bn_mod_exp, +NULL, /* dsa_mod_exp, */ +NULL, /* dsa_bn_mod_exp, */ dsa_init, dsa_finish, 0, +NULL, +NULL, NULL }; +/* These macro wrappers replace attempts to use the dsa_mod_exp() and + * bn_mod_exp() handlers in the DSA_METHOD structure. We avoid the problem of + * having a the macro work as an expression by bundling an "err_instr". So; + * + * if (!dsa->meth->bn_mod_exp(dsa, r,dsa->g,&k,dsa->p,ctx, + * dsa->method_mont_p)) goto err; + * + * can be replaced by; + * + * DSA_BN_MOD_EXP(goto err, dsa, r, dsa->g, &k, dsa->p, ctx, + * dsa->method_mont_p); + */ + +#define DSA_MOD_EXP(err_instr,dsa,rr,a1,p1,a2,p2,m,ctx,in_mont) \ + do { \ + int _tmp_res53; \ + if((dsa)->meth->dsa_mod_exp) \ + _tmp_res53 = (dsa)->meth->dsa_mod_exp((dsa), (rr), (a1), (p1), \ + (a2), (p2), (m), (ctx), (in_mont)); \ + else \ + _tmp_res53 = BN_mod_exp2_mont((rr), (a1), (p1), (a2), (p2), \ + (m), (ctx), (in_mont)); \ + if(!_tmp_res53) err_instr; \ + } while(0) +#define DSA_BN_MOD_EXP(err_instr,dsa,r,a,p,m,ctx,m_ctx) \ + do { \ + int _tmp_res53; \ + if((dsa)->meth->bn_mod_exp) \ + _tmp_res53 = (dsa)->meth->bn_mod_exp((dsa), (r), (a), (p), \ + (m), (ctx), (m_ctx)); \ + else \ + _tmp_res53 = BN_mod_exp_mont((r), (a), (p), (m), (ctx), (m_ctx)); \ + if(!_tmp_res53) err_instr; \ + } while(0) + const DSA_METHOD *DSA_OpenSSL(void) { return &openssl_dsa_meth; @@ -108,6 +138,13 @@ static DSA_SIG *dsa_do_sign(const unsigned char *dgst, int dlen, DSA *dsa) BN_init(&m); BN_init(&xr); + + if (!dsa->p || !dsa->q || !dsa->g) + { + reason=DSA_R_MISSING_PARAMETERS; + goto err; + } + s=BN_new(); if (s == NULL) goto err; @@ -165,9 +202,18 @@ err: static int dsa_sign_setup(DSA *dsa, BN_CTX *ctx_in, BIGNUM **kinvp, BIGNUM **rp) { BN_CTX *ctx; - BIGNUM k,*kinv=NULL,*r=NULL; + BIGNUM k,kq,*K,*kinv=NULL,*r=NULL; int ret=0; + if (!dsa->p || !dsa->q || !dsa->g) + { + DSAerr(DSA_F_DSA_SIGN_SETUP,DSA_R_MISSING_PARAMETERS); + return 0; + } + + BN_init(&k); + BN_init(&kq); + if (ctx_in == NULL) { if ((ctx=BN_CTX_new()) == NULL) goto err; @@ -175,25 +221,51 @@ static int dsa_sign_setup(DSA *dsa, BN_CTX *ctx_in, BIGNUM **kinvp, BIGNUM **rp) else ctx=ctx_in; - BN_init(&k); if ((r=BN_new()) == NULL) goto err; - kinv=NULL; /* Get random k */ do - if (!BN_rand_range(&k, NULL, dsa->q)) goto err; + if (!BN_rand_range(&k, dsa->q)) goto err; while (BN_is_zero(&k)); + if ((dsa->flags & DSA_FLAG_NO_EXP_CONSTTIME) == 0) + { + BN_set_flags(&k, BN_FLG_EXP_CONSTTIME); + } - if ((dsa->method_mont_p == NULL) && (dsa->flags & DSA_FLAG_CACHE_MONT_P)) + if (dsa->flags & DSA_FLAG_CACHE_MONT_P) { - if ((dsa->method_mont_p=(char *)BN_MONT_CTX_new()) != NULL) - if (!BN_MONT_CTX_set((BN_MONT_CTX *)dsa->method_mont_p, - dsa->p,ctx)) goto err; + if (!BN_MONT_CTX_set_locked(&dsa->method_mont_p, + CRYPTO_LOCK_DSA, + dsa->p, ctx)) + goto err; } /* Compute r = (g^k mod p) mod q */ - if (!ENGINE_get_DSA(dsa->engine)->bn_mod_exp(dsa, r,dsa->g,&k,dsa->p,ctx, - (BN_MONT_CTX *)dsa->method_mont_p)) goto err; + + if ((dsa->flags & DSA_FLAG_NO_EXP_CONSTTIME) == 0) + { + if (!BN_copy(&kq, &k)) goto err; + + /* We do not want timing information to leak the length of k, + * so we compute g^k using an equivalent exponent of fixed length. + * + * (This is a kludge that we need because the BN_mod_exp_mont() + * does not let us specify the desired timing behaviour.) */ + + if (!BN_add(&kq, &kq, dsa->q)) goto err; + if (BN_num_bits(&kq) <= BN_num_bits(dsa->q)) + { + if (!BN_add(&kq, &kq, dsa->q)) goto err; + } + + K = &kq; + } + else + { + K = &k; + } + DSA_BN_MOD_EXP(goto err, dsa, r, dsa->g, K, dsa->p, ctx, + dsa->method_mont_p); if (!BN_mod(r,r,dsa->q,ctx)) goto err; /* Compute part of 's = inv(k) (m + xr) mod q' */ @@ -215,6 +287,7 @@ err: if (ctx_in == NULL) BN_CTX_free(ctx); if (kinv != NULL) BN_clear_free(kinv); BN_clear_free(&k); + BN_clear_free(&kq); return(ret); } @@ -225,12 +298,31 @@ static int dsa_do_verify(const unsigned char *dgst, int dgst_len, DSA_SIG *sig, BIGNUM u1,u2,t1; BN_MONT_CTX *mont=NULL; int ret = -1; + if (!dsa->p || !dsa->q || !dsa->g) + { + DSAerr(DSA_F_DSA_DO_VERIFY,DSA_R_MISSING_PARAMETERS); + return -1; + } - if ((ctx=BN_CTX_new()) == NULL) goto err; BN_init(&u1); BN_init(&u2); BN_init(&t1); + if ((ctx=BN_CTX_new()) == NULL) goto err; + + if (BN_is_zero(sig->r) || BN_is_negative(sig->r) || + BN_ucmp(sig->r, dsa->q) >= 0) + { + ret = 0; + goto err; + } + if (BN_is_zero(sig->s) || BN_is_negative(sig->s) || + BN_ucmp(sig->s, dsa->q) >= 0) + { + ret = 0; + goto err; + } + /* Calculate W = inv(S) mod Q * save W in u2 */ if ((BN_mod_inverse(&u2,sig->s,dsa->q,ctx)) == NULL) goto err; @@ -244,44 +336,28 @@ static int dsa_do_verify(const unsigned char *dgst, int dgst_len, DSA_SIG *sig, /* u2 = r * w mod q */ if (!BN_mod_mul(&u2,sig->r,&u2,dsa->q,ctx)) goto err; - if ((dsa->method_mont_p == NULL) && (dsa->flags & DSA_FLAG_CACHE_MONT_P)) + + if (dsa->flags & DSA_FLAG_CACHE_MONT_P) { - if ((dsa->method_mont_p=(char *)BN_MONT_CTX_new()) != NULL) - if (!BN_MONT_CTX_set((BN_MONT_CTX *)dsa->method_mont_p, - dsa->p,ctx)) goto err; + mont = BN_MONT_CTX_set_locked(&dsa->method_mont_p, + CRYPTO_LOCK_DSA, dsa->p, ctx); + if (!mont) + goto err; } - mont=(BN_MONT_CTX *)dsa->method_mont_p; -#if 0 - { - BIGNUM t2; - - BN_init(&t2); - /* v = ( g^u1 * y^u2 mod p ) mod q */ - /* let t1 = g ^ u1 mod p */ - if (!BN_mod_exp_mont(&t1,dsa->g,&u1,dsa->p,ctx,mont)) goto err; - /* let t2 = y ^ u2 mod p */ - if (!BN_mod_exp_mont(&t2,dsa->pub_key,&u2,dsa->p,ctx,mont)) goto err; - /* let u1 = t1 * t2 mod p */ - if (!BN_mod_mul(&u1,&t1,&t2,dsa->p,ctx)) goto err_bn; - BN_free(&t2); - } - /* let u1 = u1 mod q */ - if (!BN_mod(&u1,&u1,dsa->q,ctx)) goto err; -#else - { - if (!ENGINE_get_DSA(dsa->engine)->dsa_mod_exp(dsa, &t1,dsa->g,&u1,dsa->pub_key,&u2, - dsa->p,ctx,mont)) goto err; + + DSA_MOD_EXP(goto err, dsa, &t1, dsa->g, &u1, dsa->pub_key, &u2, dsa->p, ctx, mont); /* BN_copy(&u1,&t1); */ /* let u1 = u1 mod q */ if (!BN_mod(&u1,&t1,dsa->q,ctx)) goto err; - } -#endif + /* V is now in u1. If the signature is correct, it will be * equal to R. */ ret=(BN_ucmp(&u1, sig->r) == 0); err: + /* XXX: surely this is wrong - if ret is 0, it just didn't verify; + there is no error in BN. Test should be ret == -1 (Ben) */ if (ret != 1) DSAerr(DSA_F_DSA_DO_VERIFY,ERR_R_BN_LIB); if (ctx != NULL) BN_CTX_free(ctx); BN_free(&u1); @@ -299,20 +375,7 @@ static int dsa_init(DSA *dsa) static int dsa_finish(DSA *dsa) { if(dsa->method_mont_p) - BN_MONT_CTX_free((BN_MONT_CTX *)dsa->method_mont_p); + BN_MONT_CTX_free(dsa->method_mont_p); return(1); } -static int dsa_mod_exp(DSA *dsa, BIGNUM *rr, BIGNUM *a1, BIGNUM *p1, - BIGNUM *a2, BIGNUM *p2, BIGNUM *m, BN_CTX *ctx, - BN_MONT_CTX *in_mont) -{ - return BN_mod_exp2_mont(rr, a1, p1, a2, p2, m, ctx, in_mont); -} - -static int dsa_bn_mod_exp(DSA *dsa, BIGNUM *r, BIGNUM *a, const BIGNUM *p, - const BIGNUM *m, BN_CTX *ctx, - BN_MONT_CTX *m_ctx) -{ - return BN_mod_exp_mont(r, a, p, m, ctx, m_ctx); -}