diff options
Diffstat (limited to 'dsa.c')
| -rw-r--r-- | dsa.c | 309 |
1 files changed, 309 insertions, 0 deletions
@@ -0,0 +1,309 @@ +/* + * Copyright (c) 2000 Markus Friedl. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. All advertising materials mentioning features or use of this software + * must display the following acknowledgement: + * This product includes software developed by Markus Friedl. + * 4. The name of the author may not be used to endorse or promote products + * derived from this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR + * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES + * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. + * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT + * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF + * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +#include "includes.h" +RCSID("$Id: dsa.c,v 1.1 2000/04/03 20:06:14 markus Exp $"); + +#include "ssh.h" +#include "xmalloc.h" +#include "buffer.h" +#include "bufaux.h" +#include "compat.h" + +#if HAVE_OPENSSL +# include <openssl/bn.h> +# include <openssl/dh.h> +# include <openssl/rsa.h> +# include <openssl/dsa.h> +# include <openssl/evp.h> +# include <openssl/bio.h> +# include <openssl/pem.h> +#endif /* HAVE_OPENSSL */ +#if HAVE_SSL +# include <ssl/bn.h> +# include <ssl/dh.h> +# include <ssl/rsa.h> +# include <ssl/dsa.h> +# include <ssl/evp.h> +# include <ssl/bio.h> +# include <ssl/pem.h> +#endif /* HAVE_SSL */ + +#include <ssl/hmac.h> +#include "kex.h" +#include "key.h" + +#define INTBLOB_LEN 20 +#define SIGBLOB_LEN (2*INTBLOB_LEN) + +Key * +dsa_serverkey_from_blob( + char *serverhostkey, int serverhostkeylen) +{ + Buffer b; + char *ktype; + int rlen; + DSA *dsa; + Key *key; + + /* fetch & parse DSA/DSS pubkey */ + key = key_new(KEY_DSA); + dsa = key->dsa; + buffer_init(&b); + buffer_append(&b, serverhostkey, serverhostkeylen); + ktype = buffer_get_string(&b, NULL); + if (strcmp(KEX_DSS, ktype) != 0) { + log("dsa_serverkey_from_blob: cannot handle type %s", ktype); + key_free(key); + return NULL; + } + buffer_get_bignum2(&b, dsa->p); + buffer_get_bignum2(&b, dsa->q); + buffer_get_bignum2(&b, dsa->g); + buffer_get_bignum2(&b, dsa->pub_key); + rlen = buffer_len(&b); + if(rlen != 0) + log("dsa_serverkey_from_blob: remaining bytes in serverhostkey %d", rlen); + buffer_free(&b); + + log("keytype %s", ktype); +#ifdef DEBUG_DSS + DSA_print_fp(stderr, dsa, 8); +#endif + return key; +} +DSA * +dsa_load_private(char *filename) +{ + DSA *dsa; + BIO *in; + + in = BIO_new(BIO_s_file()); + if (in == NULL) + fatal("BIO_new failed"); + if (BIO_read_filename(in, filename) <= 0) + fatal("BIO_read failed %s: %s", filename, strerror(errno)); + fprintf(stderr, "read DSA private key\n"); + dsa = PEM_read_bio_DSAPrivateKey(in,NULL,NULL,NULL); + if (dsa == NULL) + fatal("PEM_read_bio_DSAPrivateKey failed %s", filename); + BIO_free(in); + return dsa; +} +Key * +dsa_get_serverkey(char *filename) +{ + Key *k = key_new(KEY_EMPTY); + k->type = KEY_DSA; + k->dsa = dsa_load_private(filename); +#ifdef DEBUG_DSS + DSA_print_fp(stderr, dsa, 8); +#endif + return k; +} +int +dsa_make_serverkey_blob(Key *key, unsigned char **blobp, unsigned int *lenp) +{ + Buffer b; + int len; + unsigned char *buf; + + if (key == NULL || key->type != KEY_DSA) + return 0; + buffer_init(&b); + buffer_put_cstring(&b, KEX_DSS); + buffer_put_bignum2(&b, key->dsa->p); + buffer_put_bignum2(&b, key->dsa->q); + buffer_put_bignum2(&b, key->dsa->g); + buffer_put_bignum2(&b, key->dsa->pub_key); + len = buffer_len(&b); + buf = xmalloc(len); + memcpy(buf, buffer_ptr(&b), len); + memset(buffer_ptr(&b), 0, len); + buffer_free(&b); + if (lenp != NULL) + *lenp = len; + if (blobp != NULL) + *blobp = buf; + return len; +} +int +dsa_sign( + Key *key, + unsigned char **sigp, int *lenp, + unsigned char *hash, int hlen) +{ + unsigned char *digest; + unsigned char *ret; + DSA_SIG *sig; + EVP_MD *evp_md = EVP_sha1(); + EVP_MD_CTX md; + unsigned int rlen; + unsigned int slen; + unsigned int len; + unsigned char sigblob[SIGBLOB_LEN]; + Buffer b; + + if (key == NULL || key->type != KEY_DSA || key->dsa == NULL) { + log("dsa_sign: no DSA key"); + return -1; + } + digest = xmalloc(evp_md->md_size); + EVP_DigestInit(&md, evp_md); + EVP_DigestUpdate(&md, hash, hlen); + EVP_DigestFinal(&md, digest, NULL); + + sig = DSA_do_sign(digest, evp_md->md_size, key->dsa); + + rlen = BN_num_bytes(sig->r); + slen = BN_num_bytes(sig->s); + if (rlen > INTBLOB_LEN || slen > INTBLOB_LEN) { + log("bad sig size %d %d", rlen, slen); + DSA_SIG_free(sig); + return -1; + } + log("sig size %d %d", rlen, slen); + + memset(sigblob, 0, SIGBLOB_LEN); + BN_bn2bin(sig->r, sigblob+ SIGBLOB_LEN - INTBLOB_LEN - rlen); + BN_bn2bin(sig->s, sigblob+ SIGBLOB_LEN - slen); + DSA_SIG_free(sig); + + if (datafellows) { + log("datafellows"); + ret = xmalloc(SIGBLOB_LEN); + memcpy(ret, sigblob, SIGBLOB_LEN); + if (lenp != NULL) + *lenp = SIGBLOB_LEN; + if (sigp != NULL) + *sigp = ret; + } else { + /* ietf-drafts */ + buffer_init(&b); + buffer_put_cstring(&b, KEX_DSS); + buffer_put_string(&b, sigblob, SIGBLOB_LEN); + len = buffer_len(&b); + ret = xmalloc(len); + memcpy(ret, buffer_ptr(&b), len); + buffer_free(&b); + if (lenp != NULL) + *lenp = len; + if (sigp != NULL) + *sigp = ret; + } + return 0; +} +int +dsa_verify( + Key *key, + unsigned char *signature, int signaturelen, + unsigned char *hash, int hlen) +{ + Buffer b; + unsigned char *digest; + DSA_SIG *sig; + EVP_MD *evp_md = EVP_sha1(); + EVP_MD_CTX md; + char *ktype; + unsigned char *sigblob; + char *txt; + unsigned int len; + int rlen; + int ret; + + if (key == NULL || key->type != KEY_DSA || key->dsa == NULL) { + log("dsa_verify: no DSA key"); + return -1; + } + + if (datafellows && signaturelen != SIGBLOB_LEN) { + log("heh? datafellows ssh2 complies with ietf-drafts????"); + datafellows = 0; + } + + log("len %d datafellows %d", signaturelen, datafellows); + + /* fetch signature */ + if (datafellows) { + sigblob = signature; + len = signaturelen; + } else { + /* ietf-drafts */ + buffer_init(&b); + buffer_append(&b, (char *) signature, signaturelen); + ktype = buffer_get_string(&b, NULL); + sigblob = (unsigned char *)buffer_get_string(&b, &len); + rlen = buffer_len(&b); + if(rlen != 0) + log("remaining bytes in signature %d", rlen); + buffer_free(&b); + } + + if (len != SIGBLOB_LEN) { + fatal("bad sigbloblen %d != SIGBLOB_LEN", len); + } + + /* parse signature */ + sig = DSA_SIG_new(); + sig->r = BN_new(); + sig->s = BN_new(); + BN_bin2bn(sigblob, INTBLOB_LEN, sig->r); + BN_bin2bn(sigblob+ INTBLOB_LEN, INTBLOB_LEN, sig->s); + if (!datafellows) { + memset(sigblob, 0, len); + xfree(sigblob); + } + + /* sha1 the signed data (== session_id == hash) */ + digest = xmalloc(evp_md->md_size); + EVP_DigestInit(&md, evp_md); + EVP_DigestUpdate(&md, hash, hlen); + EVP_DigestFinal(&md, digest, NULL); + + ret = DSA_do_verify(digest, evp_md->md_size, sig, key->dsa); + + memset(digest, 0, evp_md->md_size); + xfree(digest); + DSA_SIG_free(sig); + + switch (ret) { + case 1: + txt = "correct"; + break; + case 0: + txt = "incorrect"; + break; + case -1: + default: + txt = "error"; + break; + } + log("dsa_verify: signature %s", txt); + return ret; +} |