crypto/dsa/dsa_sign.c

   1 /*
   2  * Copyright 1995-2020 The OpenSSL Project Authors. All Rights Reserved.
   3  *
   4  * Licensed under the Apache License 2.0 (the "License").  You may not use
   5  * this file except in compliance with the License.  You can obtain a copy
   6  * in the file LICENSE in the source distribution or at
   7  * https://www.openssl.org/source/license.html
   8  */
   9
  10 /*
  11  * DSA low level APIs are deprecated for public use, but still ok for
  12  * internal use.
  13  */
  14 #include "internal/deprecated.h"
  15
  16 #include <openssl/bn.h>
  17 #include "internal/cryptlib.h"
  18 #include "dsa_local.h"
  19 #include "crypto/asn1_dsa.h"
  20 #include "crypto/dsa.h"
  21
  22 DSA_SIG *DSA_do_sign(const unsigned char *dgst, int dlen, DSA *dsa)
  23 {
  24     return dsa->meth->dsa_do_sign(dgst, dlen, dsa);
  25 }
  26
  27 #ifndef OPENSSL_NO_DEPRECATED_3_0
  28 int DSA_sign_setup(DSA *dsa, BN_CTX *ctx_in, BIGNUM **kinvp, BIGNUM **rp)
  29 {
  30     return dsa->meth->dsa_sign_setup(dsa, ctx_in, kinvp, rp);
  31 }
  32 #endif
  33
  34 DSA_SIG *DSA_SIG_new(void)
  35 {
  36     DSA_SIG *sig = OPENSSL_zalloc(sizeof(*sig));
  37     if (sig == NULL)
  38         ERR_raise(ERR_LIB_DSA, ERR_R_MALLOC_FAILURE);
  39     return sig;
  40 }
  41
  42 void DSA_SIG_free(DSA_SIG *sig)
  43 {
  44     if (sig == NULL)
  45         return;
  46     BN_clear_free(sig->r);
  47     BN_clear_free(sig->s);
  48     OPENSSL_free(sig);
  49 }
  50
  51 DSA_SIG *d2i_DSA_SIG(DSA_SIG **psig, const unsigned char **ppin, long len)
  52 {
  53     DSA_SIG *sig;
  54
  55     if (len < 0)
  56         return NULL;
  57     if (psig != NULL && *psig != NULL) {
  58         sig = *psig;
  59     } else {
  60         sig = DSA_SIG_new();
  61         if (sig == NULL)
  62             return NULL;
  63     }
  64     if (sig->r == NULL)
  65         sig->r = BN_new();
  66     if (sig->s == NULL)
  67         sig->s = BN_new();
  68     if (ossl_decode_der_dsa_sig(sig->r, sig->s, ppin, (size_t)len) == 0) {
  69         if (psig == NULL || *psig == NULL)
  70             DSA_SIG_free(sig);
  71         return NULL;
  72     }
  73     if (psig != NULL && *psig == NULL)
  74         *psig = sig;
  75     return sig;
  76 }
  77
  78 int i2d_DSA_SIG(const DSA_SIG *sig, unsigned char **ppout)
  79 {
  80     BUF_MEM *buf = NULL;
  81     size_t encoded_len;
  82     WPACKET pkt;
  83
  84     if (ppout == NULL) {
  85         if (!WPACKET_init_null(&pkt, 0))
  86             return -1;
  87     } else if (*ppout == NULL) {
  88         if ((buf = BUF_MEM_new()) == NULL
  89                 || !WPACKET_init_len(&pkt, buf, 0)) {
  90             BUF_MEM_free(buf);
  91             return -1;
  92         }
  93     } else {
  94         if (!WPACKET_init_static_len(&pkt, *ppout, SIZE_MAX, 0))
  95             return -1;
  96     }
  97
  98     if (!encode_der_dsa_sig(&pkt, sig->r, sig->s)
  99             || !WPACKET_get_total_written(&pkt, &encoded_len)
 100             || !WPACKET_finish(&pkt)) {
 101         BUF_MEM_free(buf);
 102         WPACKET_cleanup(&pkt);
 103         return -1;
 104     }
 105
 106     if (ppout != NULL) {
 107         if (*ppout == NULL) {
 108             *ppout = (unsigned char *)buf->data;
 109             buf->data = NULL;
 110             BUF_MEM_free(buf);
 111         } else {
 112             *ppout += encoded_len;
 113         }
 114     }
 115
 116     return (int)encoded_len;
 117 }
 118
 119 int DSA_size(const DSA *dsa)
 120 {
 121     int ret;
 122     DSA_SIG sig;
 123
 124     sig.r = sig.s = dsa->params.q;
 125     ret = i2d_DSA_SIG(&sig, NULL);
 126
 127     if (ret < 0)
 128         ret = 0;
 129     return ret;
 130 }
 131
 132 void DSA_SIG_get0(const DSA_SIG *sig, const BIGNUM **pr, const BIGNUM **ps)
 133 {
 134     if (pr != NULL)
 135         *pr = sig->r;
 136     if (ps != NULL)
 137         *ps = sig->s;
 138 }
 139
 140 int DSA_SIG_set0(DSA_SIG *sig, BIGNUM *r, BIGNUM *s)
 141 {
 142     if (r == NULL || s == NULL)
 143         return 0;
 144     BN_clear_free(sig->r);
 145     BN_clear_free(sig->s);
 146     sig->r = r;
 147     sig->s = s;
 148     return 1;
 149 }
 150
 151 int dsa_sign_int(int type, const unsigned char *dgst,
 152                  int dlen, unsigned char *sig, unsigned int *siglen, DSA *dsa)
 153 {
 154     DSA_SIG *s;
 155
 156     /* legacy case uses the method table */
 157     if (dsa->libctx == NULL || dsa->meth != DSA_get_default_method())
 158         s = DSA_do_sign(dgst, dlen, dsa);
 159     else
 160         s = dsa_do_sign_int(dgst, dlen, dsa);
 161     if (s == NULL) {
 162         *siglen = 0;
 163         return 0;
 164     }
 165     *siglen = i2d_DSA_SIG(s, &sig);
 166     DSA_SIG_free(s);
 167     return 1;
 168 }
 169
 170 int DSA_sign(int type, const unsigned char *dgst, int dlen,
 171              unsigned char *sig, unsigned int *siglen, DSA *dsa)
 172 {
 173     return dsa_sign_int(type, dgst, dlen, sig, siglen, dsa);
 174 }
 175
 176 /* data has already been hashed (probably with SHA or SHA-1). */
 177 /*-
 178  * returns
 179  *      1: correct signature
 180  *      0: incorrect signature
 181  *     -1: error
 182  */
 183 int DSA_verify(int type, const unsigned char *dgst, int dgst_len,
 184                const unsigned char *sigbuf, int siglen, DSA *dsa)
 185 {
 186     DSA_SIG *s;
 187     const unsigned char *p = sigbuf;
 188     unsigned char *der = NULL;
 189     int derlen = -1;
 190     int ret = -1;
 191
 192     s = DSA_SIG_new();
 193     if (s == NULL)
 194         return ret;
 195     if (d2i_DSA_SIG(&s, &p, siglen) == NULL)
 196         goto err;
 197     /* Ensure signature uses DER and doesn't have trailing garbage */
 198     derlen = i2d_DSA_SIG(s, &der);
 199     if (derlen != siglen || memcmp(sigbuf, der, derlen))
 200         goto err;
 201     ret = DSA_do_verify(dgst, dgst_len, s, dsa);
 202  err:
 203     OPENSSL_clear_free(der, derlen);
 204     DSA_SIG_free(s);
 205     return ret;
 206 }
 207