+/* $OpenBSD: ssh-dss.c,v 1.24 2006/11/06 21:25:28 markus Exp $ */
/*
* Copyright (c) 2000 Markus Friedl. All rights reserved.
*
*/
#include "includes.h"
-RCSID("$OpenBSD: ssh-dss.c,v 1.1 2000/11/12 19:50:38 markus Exp $");
-#include "ssh.h"
-#include "xmalloc.h"
-#include "buffer.h"
-#include "bufaux.h"
-#include "compat.h"
+#include <sys/types.h>
#include <openssl/bn.h>
-#include <openssl/rsa.h>
-#include <openssl/dsa.h>
#include <openssl/evp.h>
+#include <stdarg.h>
+#include <string.h>
+
+#include "xmalloc.h"
+#include "buffer.h"
+#include "compat.h"
+#include "log.h"
#include "key.h"
#define INTBLOB_LEN 20
#define SIGBLOB_LEN (2*INTBLOB_LEN)
int
-ssh_dss_sign(
- Key *key,
- unsigned char **sigp, int *lenp,
- unsigned char *data, int datalen)
+ssh_dss_sign(const Key *key, u_char **sigp, u_int *lenp,
+ const u_char *data, u_int datalen)
{
- unsigned char *digest;
- unsigned char *ret;
DSA_SIG *sig;
- EVP_MD *evp_md = EVP_sha1();
+ const EVP_MD *evp_md = EVP_sha1();
EVP_MD_CTX md;
- unsigned int rlen;
- unsigned int slen;
- unsigned int len;
- unsigned char sigblob[SIGBLOB_LEN];
+ u_char digest[EVP_MAX_MD_SIZE], sigblob[SIGBLOB_LEN];
+ u_int rlen, slen, len, dlen;
Buffer b;
if (key == NULL || key->type != KEY_DSA || key->dsa == NULL) {
error("ssh_dss_sign: no DSA key");
return -1;
}
- digest = xmalloc(evp_md->md_size);
EVP_DigestInit(&md, evp_md);
EVP_DigestUpdate(&md, data, datalen);
- EVP_DigestFinal(&md, digest, NULL);
+ EVP_DigestFinal(&md, digest, &dlen);
+
+ sig = DSA_do_sign(digest, dlen, key->dsa);
+ memset(digest, 'd', sizeof(digest));
- sig = DSA_do_sign(digest, evp_md->md_size, key->dsa);
if (sig == NULL) {
- fatal("ssh_dss_sign: cannot sign");
+ error("ssh_dss_sign: sign failed");
+ return -1;
}
rlen = BN_num_bytes(sig->r);
slen = BN_num_bytes(sig->s);
if (rlen > INTBLOB_LEN || slen > INTBLOB_LEN) {
- error("bad sig size %d %d", rlen, slen);
+ error("bad sig size %u %u", rlen, slen);
DSA_SIG_free(sig);
return -1;
}
- debug("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 & SSH_BUG_SIGBLOB) {
- debug("datafellows");
- ret = xmalloc(SIGBLOB_LEN);
- memcpy(ret, sigblob, SIGBLOB_LEN);
if (lenp != NULL)
*lenp = SIGBLOB_LEN;
- if (sigp != NULL)
- *sigp = ret;
+ if (sigp != NULL) {
+ *sigp = xmalloc(SIGBLOB_LEN);
+ memcpy(*sigp, sigblob, SIGBLOB_LEN);
+ }
} else {
/* ietf-drafts */
buffer_init(&b);
buffer_put_cstring(&b, "ssh-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;
+ if (sigp != NULL) {
+ *sigp = xmalloc(len);
+ memcpy(*sigp, buffer_ptr(&b), len);
+ }
+ buffer_free(&b);
}
return 0;
}
int
-ssh_dss_verify(
- Key *key,
- unsigned char *signature, int signaturelen,
- unsigned char *data, int datalen)
+ssh_dss_verify(const Key *key, const u_char *signature, u_int signaturelen,
+ const u_char *data, u_int datalen)
{
- Buffer b;
- unsigned char *digest;
DSA_SIG *sig;
- EVP_MD *evp_md = EVP_sha1();
+ const EVP_MD *evp_md = EVP_sha1();
EVP_MD_CTX md;
- unsigned char *sigblob;
- char *txt;
- unsigned int len, dlen;
- int rlen;
- int ret;
+ u_char digest[EVP_MAX_MD_SIZE], *sigblob;
+ u_int len, dlen;
+ int rlen, ret;
+ Buffer b;
if (key == NULL || key->type != KEY_DSA || key->dsa == NULL) {
error("ssh_dss_verify: no DSA key");
return -1;
}
- if (!(datafellows & SSH_BUG_SIGBLOB) &&
- signaturelen == SIGBLOB_LEN) {
- datafellows |= ~SSH_BUG_SIGBLOB;
- log("autodetect SSH_BUG_SIGBLOB");
- } else if ((datafellows & SSH_BUG_SIGBLOB) &&
- signaturelen != SIGBLOB_LEN) {
- log("autoremove SSH_BUG_SIGBLOB");
- datafellows &= ~SSH_BUG_SIGBLOB;
- }
-
- debug("len %d datafellows %d", signaturelen, datafellows);
-
/* fetch signature */
if (datafellows & SSH_BUG_SIGBLOB) {
- sigblob = signature;
+ sigblob = xmalloc(signaturelen);
+ memcpy(sigblob, signature, signaturelen);
len = signaturelen;
} else {
/* ietf-drafts */
char *ktype;
buffer_init(&b);
- buffer_append(&b, (char *) signature, signaturelen);
+ buffer_append(&b, signature, signaturelen);
ktype = buffer_get_string(&b, NULL);
if (strcmp("ssh-dss", ktype) != 0) {
error("ssh_dss_verify: cannot handle type %s", ktype);
buffer_free(&b);
+ xfree(ktype);
return -1;
}
- sigblob = (unsigned char *)buffer_get_string(&b, &len);
+ xfree(ktype);
+ sigblob = buffer_get_string(&b, &len);
rlen = buffer_len(&b);
- if(rlen != 0) {
- error("remaining bytes in signature %d", rlen);
- buffer_free(&b);
+ buffer_free(&b);
+ if (rlen != 0) {
+ error("ssh_dss_verify: "
+ "remaining bytes in signature %d", rlen);
+ xfree(sigblob);
return -1;
}
- buffer_free(&b);
- xfree(ktype);
}
if (len != SIGBLOB_LEN) {
- fatal("bad sigbloblen %d != SIGBLOB_LEN", len);
+ fatal("bad sigbloblen %u != 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 & SSH_BUG_SIGBLOB)) {
- memset(sigblob, 0, len);
- xfree(sigblob);
- }
-
+ if ((sig = DSA_SIG_new()) == NULL)
+ fatal("ssh_dss_verify: DSA_SIG_new failed");
+ if ((sig->r = BN_new()) == NULL)
+ fatal("ssh_dss_verify: BN_new failed");
+ if ((sig->s = BN_new()) == NULL)
+ fatal("ssh_dss_verify: BN_new failed");
+ if ((BN_bin2bn(sigblob, INTBLOB_LEN, sig->r) == NULL) ||
+ (BN_bin2bn(sigblob+ INTBLOB_LEN, INTBLOB_LEN, sig->s) == NULL))
+ fatal("ssh_dss_verify: BN_bin2bn failed");
+
+ /* clean up */
+ memset(sigblob, 0, len);
+ xfree(sigblob);
+
/* sha1 the data */
- dlen = evp_md->md_size;
- digest = xmalloc(dlen);
EVP_DigestInit(&md, evp_md);
EVP_DigestUpdate(&md, data, datalen);
- EVP_DigestFinal(&md, digest, NULL);
+ EVP_DigestFinal(&md, digest, &dlen);
ret = DSA_do_verify(digest, dlen, sig, key->dsa);
+ memset(digest, 'd', sizeof(digest));
- memset(digest, 0, dlen);
- xfree(digest);
DSA_SIG_free(sig);
- switch (ret) {
- case 1:
- txt = "correct";
- break;
- case 0:
- txt = "incorrect";
- break;
- case -1:
- default:
- txt = "error";
- break;
- }
- debug("ssh_dss_verify: signature %s", txt);
+ debug("ssh_dss_verify: signature %s",
+ ret == 1 ? "correct" : ret == 0 ? "incorrect" : "error");
return ret;
}