crypto/dsa/dsa_sign.c

   1 /*
   2  * Copyright 1995-2023 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
  38     return sig;
  39 }
  40
  41 void DSA_SIG_free(DSA_SIG *sig)
  42 {
  43     if (sig == NULL)
  44         return;
  45     BN_clear_free(sig->r);
  46     BN_clear_free(sig->s);
  47     OPENSSL_free(sig);
  48 }
  49
  50 DSA_SIG *d2i_DSA_SIG(DSA_SIG **psig, const unsigned char **ppin, long len)
  51 {
  52     DSA_SIG *sig;
  53
  54     if (len < 0)
  55         return NULL;
  56     if (psig != NULL && *psig != NULL) {
  57         sig = *psig;
  58     } else {
  59         sig = DSA_SIG_new();
  60         if (sig == NULL)
  61             return NULL;
  62     }
  63     if (sig->r == NULL)
  64         sig->r = BN_new();
  65     if (sig->s == NULL)
  66         sig->s = BN_new();
  67     if (sig->r == NULL || sig->s == NULL
  68         || 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 (!ossl_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 = -1;
 122     DSA_SIG sig;
 123
 124     if (dsa->params.q != NULL) {
 125         sig.r = sig.s = dsa->params.q;
 126         ret = i2d_DSA_SIG(&sig, NULL);
 127
 128         if (ret < 0)
 129             ret = 0;
 130     }
 131     return ret;
 132 }
 133
 134 void DSA_SIG_get0(const DSA_SIG *sig, const BIGNUM **pr, const BIGNUM **ps)
 135 {
 136     if (pr != NULL)
 137         *pr = sig->r;
 138     if (ps != NULL)
 139         *ps = sig->s;
 140 }
 141
 142 int DSA_SIG_set0(DSA_SIG *sig, BIGNUM *r, BIGNUM *s)
 143 {
 144     if (r == NULL || s == NULL)
 145         return 0;
 146     BN_clear_free(sig->r);
 147     BN_clear_free(sig->s);
 148     sig->r = r;
 149     sig->s = s;
 150     return 1;
 151 }
 152
 153 int ossl_dsa_sign_int(int type, const unsigned char *dgst, int dlen,
 154                       unsigned char *sig, unsigned int *siglen, DSA *dsa,
 155                       unsigned int nonce_type, const char *digestname,
 156                       OSSL_LIB_CTX *libctx, const char *propq)
 157 {
 158     DSA_SIG *s;
 159
 160     /* legacy case uses the method table */
 161     if (dsa->libctx == NULL || dsa->meth != DSA_get_default_method())
 162         s = DSA_do_sign(dgst, dlen, dsa);
 163     else
 164         s = ossl_dsa_do_sign_int(dgst, dlen, dsa,
 165                                  nonce_type, digestname, libctx, propq);
 166     if (s == NULL) {
 167         *siglen = 0;
 168         return 0;
 169     }
 170     *siglen = i2d_DSA_SIG(s, sig != NULL ? &sig : NULL);
 171     DSA_SIG_free(s);
 172     return 1;
 173 }
 174
 175 int DSA_sign(int type, const unsigned char *dgst, int dlen,
 176              unsigned char *sig, unsigned int *siglen, DSA *dsa)
 177 {
 178     return ossl_dsa_sign_int(type, dgst, dlen, sig, siglen, dsa,
 179                              0, NULL, NULL, NULL);
 180 }
 181
 182 /* data has already been hashed (probably with SHA or SHA-1). */
 183 /*-
 184  * returns
 185  *      1: correct signature
 186  *      0: incorrect signature
 187  *     -1: error
 188  */
 189 int DSA_verify(int type, const unsigned char *dgst, int dgst_len,
 190                const unsigned char *sigbuf, int siglen, DSA *dsa)
 191 {
 192     DSA_SIG *s;
 193     const unsigned char *p = sigbuf;
 194     unsigned char *der = NULL;
 195     int derlen = -1;
 196     int ret = -1;
 197
 198     s = DSA_SIG_new();
 199     if (s == NULL)
 200         return ret;
 201     if (d2i_DSA_SIG(&s, &p, siglen) == NULL)
 202         goto err;
 203     /* Ensure signature uses DER and doesn't have trailing garbage */
 204     derlen = i2d_DSA_SIG(s, &der);
 205     if (derlen != siglen || memcmp(sigbuf, der, derlen))
 206         goto err;
 207     ret = DSA_do_verify(dgst, dgst_len, s, dsa);
 208  err:
 209     OPENSSL_clear_free(der, derlen);
 210     DSA_SIG_free(s);
 211     return ret;
 212 }