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/* $OpenBSD: ssh2.c,v 1.4 2014/07/07 17:02:22 bluhm Exp $ */
/*
* ssh2.c
*
* Copyright (c) 2005 Marius Eriksen <marius@openbsd.org>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include <sys/types.h>
#include <sys/uio.h>
#include <netinet/in.h>
#include <arpa/nameser.h>
#include <openssl/ssl.h>
#include <openssl/des.h>
#include <openssl/md5.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <resolv.h>
#include <err.h>
#include "key.h"
#include "ssh2.h"
#define GET_32BIT(cp) (((u_long)(u_char)(cp)[0] << 24) | \
((u_long)(u_char)(cp)[1] << 16) | \
((u_long)(u_char)(cp)[2] << 8) | \
((u_long)(u_char)(cp)[3]))
/* From OpenSSH */
static int
_uudecode(const char *src, u_char *target, size_t targsize)
{
int len;
char *encoded, *p;
/* copy the 'readonly' source */
if ((encoded = strdup(src)) == NULL)
err(1, "strdup");
/* skip whitespace and data */
for (p = encoded; *p == ' ' || *p == '\t'; p++)
;
for (; *p != '\0' && *p != ' ' && *p != '\t'; p++)
;
/* and remove trailing whitespace because __b64_pton needs this */
*p = '\0';
len = __b64_pton(encoded, target, targsize);
free(encoded);
return len;
}
/*
* Small compatibility layer for the OpenSSH buffers. Only what we
* need here.
*/
static int
_keyfromstr(char *str, int len)
{
if (strncmp(str, "rsa", len) == 0 ||
strncmp(str, "ssh-rsa", len) == 0)
return KEY_RSA;
else if (strncmp(str, "dsa", len) == 0 ||
strncmp(str, "ssh-dss", len) == 0)
return KEY_DSA;
return (-1);
}
static int
_read_int(struct iovec *iov, int *ival)
{
if (iov->iov_len < 4)
return (-1);
iov->iov_len -= 4;
*ival = GET_32BIT((u_char *)iov->iov_base);
iov->iov_base = (u_char*)iov->iov_base + 4;
return (0);
}
static int
_read_opaque(struct iovec *iov, u_char **buf, int *len)
{
if (_read_int(iov, len) < 0 || *len < 0)
return (-1);
if (iov->iov_len < (size_t)*len)
return (-1);
iov->iov_len -= *len;
*buf = iov->iov_base;
iov->iov_base = (u_char*)iov->iov_base + *len;
return (0);
}
static int
_read_bignum(struct iovec *iov, BIGNUM *bn)
{
u_char *bp;
int blen;
if (_read_opaque(iov, &bp, &blen) < 0)
return (-1);
if ((blen > 0 && bp[0] & 0x80) || /* No negative values */
(blen > 8*1024)) /* Too large */
return (-1);
BN_bin2bn(bp, blen, bn);
return (0);
}
int
ssh2_load_public(struct key *k, struct iovec *iovp)
{
int len, keytype, error = 0;
u_char *bp;
struct iovec iov;
/* iov->iov_base is NULL terminated */
char *cp0, *savep = NULL, *cp = iovp->iov_base;
if ((cp0 = strchr(cp, ' ')) == NULL)
return (-1);
len = cp0 - cp;
if ((keytype = _keyfromstr(cp, len)) < 0)
return (-1);
/* cp0 is a space (' '), so we have at least one more */
cp = cp0 + 1;
len = 2*strlen(cp);
if ((savep = iov.iov_base = malloc(len)) == NULL)
err(1, "malloc(%d)", len);
iov.iov_len = _uudecode(cp, iov.iov_base, len);
if (_read_opaque(&iov, &bp, &len) < 0 ||
keytype != _keyfromstr(bp, len)) {
error = -1;
goto out;
}
k->type = keytype;
switch (keytype) {
case KEY_RSA: {
RSA *rsa;
if ((rsa = RSA_new()) == NULL ||
(rsa->e = BN_new()) == NULL ||
(rsa->n = BN_new()) == NULL)
errx(1, "BN_new");
if (_read_bignum(&iov, rsa->e) < 0 ||
_read_bignum(&iov, rsa->n) < 0) {
error = -1;
RSA_free(rsa);
goto out;
}
k->data = (void *)rsa;
break;
}
case KEY_DSA: {
DSA *dsa;
if ((dsa = DSA_new()) == NULL ||
(dsa->p = BN_new()) == NULL ||
(dsa->q = BN_new()) == NULL ||
(dsa->g = BN_new()) == NULL ||
(dsa->pub_key = BN_new()) == NULL)
errx(1, "BN_new");
if (_read_bignum(&iov, dsa->p) < 0 ||
_read_bignum(&iov, dsa->q) < 0 ||
_read_bignum(&iov, dsa->g) < 0 ||
_read_bignum(&iov, dsa->pub_key) < 0) {
error = -1;
DSA_free(dsa);
goto out;
}
k->data = (void *)dsa;
break;
}
default:
error = -1;
}
#if 0
if (iov->iov_len != 0)
/* Sanity check. */
return (-1);
#endif
out:
if (savep != NULL)
free(savep);
return (error);
}
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