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041ab7c1e7
openssh/key.c
Damien Miller 041ab7c1e7 - djm@cvs.openbsd.org 2010/09/09 10:45:45 
[kex.c kex.h kexecdh.c key.c key.h monitor.c ssh-ecdsa.c]
     ECDH/ECDSA compliance fix: these methods vary the hash function they use
     (SHA256/384/512) depending on the length of the curve in use. The previous
     code incorrectly used SHA256 in all cases.

     This fix will cause authentication failure when using 384 or 521-bit curve
     keys if one peer hasn't been upgraded and the other has. (256-bit curve
     keys work ok). In particular you may need to specify HostkeyAlgorithms
     when connecting to a server that has not been upgraded from an upgraded
     client.

     ok naddy@
2010-09-10 11:23:34 +10:00

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/* $OpenBSD: key.c,v 1.93 2010/09/09 10:45:45 djm Exp $ */
/*
* read_bignum():
* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
*
* As far as I am concerned, the code I have written for this software
* can be used freely for any purpose. Any derived versions of this
* software must be clearly marked as such, and if the derived work is
* incompatible with the protocol description in the RFC file, it must be
* called by a name other than "ssh" or "Secure Shell".
*
*
* Copyright (c) 2000, 2001 Markus Friedl. All rights reserved.
* Copyright (c) 2008 Alexander von Gernler. 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.
*
* 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"
#include <sys/param.h>
#include <sys/types.h>
#include <openssl/evp.h>
#include <openbsd-compat/openssl-compat.h>
#include <stdarg.h>
#include <stdio.h>
#include <string.h>
#include "xmalloc.h"
#include "key.h"
#include "rsa.h"
#include "uuencode.h"
#include "buffer.h"
#include "log.h"
#include "misc.h"
#include "ssh2.h"
static struct KeyCert *
cert_new(void)
{
struct KeyCert *cert;
cert = xcalloc(1, sizeof(*cert));
buffer_init(&cert->certblob);
buffer_init(&cert->critical);
buffer_init(&cert->extensions);
cert->key_id = NULL;
cert->principals = NULL;
cert->signature_key = NULL;
return cert;
}
Key *
key_new(int type)
{
Key *k;
RSA *rsa;
DSA *dsa;
k = xcalloc(1, sizeof(*k));
k->type = type;
k->ecdsa = NULL;
k->ecdsa_nid = -1;
k->dsa = NULL;
k->rsa = NULL;
k->cert = NULL;
switch (k->type) {
case KEY_RSA1:
case KEY_RSA:
case KEY_RSA_CERT_V00:
case KEY_RSA_CERT:
if ((rsa = RSA_new()) == NULL)
fatal("key_new: RSA_new failed");
if ((rsa->n = BN_new()) == NULL)
fatal("key_new: BN_new failed");
if ((rsa->e = BN_new()) == NULL)
fatal("key_new: BN_new failed");
k->rsa = rsa;
break;
case KEY_DSA:
case KEY_DSA_CERT_V00:
case KEY_DSA_CERT:
if ((dsa = DSA_new()) == NULL)
fatal("key_new: DSA_new failed");
if ((dsa->p = BN_new()) == NULL)
fatal("key_new: BN_new failed");
if ((dsa->q = BN_new()) == NULL)
fatal("key_new: BN_new failed");
if ((dsa->g = BN_new()) == NULL)
fatal("key_new: BN_new failed");
if ((dsa->pub_key = BN_new()) == NULL)
fatal("key_new: BN_new failed");
k->dsa = dsa;
break;
case KEY_ECDSA:
case KEY_ECDSA_CERT:
/* Cannot do anything until we know the group */
break;
case KEY_UNSPEC:
break;
default:
fatal("key_new: bad key type %d", k->type);
break;
}
if (key_is_cert(k))
k->cert = cert_new();
return k;
}
void
key_add_private(Key *k)
{
switch (k->type) {
case KEY_RSA1:
case KEY_RSA:
case KEY_RSA_CERT_V00:
case KEY_RSA_CERT:
if ((k->rsa->d = BN_new()) == NULL)
fatal("key_new_private: BN_new failed");
if ((k->rsa->iqmp = BN_new()) == NULL)
fatal("key_new_private: BN_new failed");
if ((k->rsa->q = BN_new()) == NULL)
fatal("key_new_private: BN_new failed");
if ((k->rsa->p = BN_new()) == NULL)
fatal("key_new_private: BN_new failed");
if ((k->rsa->dmq1 = BN_new()) == NULL)
fatal("key_new_private: BN_new failed");
if ((k->rsa->dmp1 = BN_new()) == NULL)
fatal("key_new_private: BN_new failed");
break;
case KEY_DSA:
case KEY_DSA_CERT_V00:
case KEY_DSA_CERT:
if ((k->dsa->priv_key = BN_new()) == NULL)
fatal("key_new_private: BN_new failed");
break;
case KEY_ECDSA:
case KEY_ECDSA_CERT:
/* Cannot do anything until we know the group */
break;
case KEY_UNSPEC:
break;
default:
break;
}
}
Key *
key_new_private(int type)
{
Key *k = key_new(type);
key_add_private(k);
return k;
}
static void
cert_free(struct KeyCert *cert)
{
u_int i;
buffer_free(&cert->certblob);
buffer_free(&cert->critical);
buffer_free(&cert->extensions);
if (cert->key_id != NULL)
xfree(cert->key_id);
for (i = 0; i < cert->nprincipals; i++)
xfree(cert->principals[i]);
if (cert->principals != NULL)
xfree(cert->principals);
if (cert->signature_key != NULL)
key_free(cert->signature_key);
}
void
key_free(Key *k)
{
if (k == NULL)
fatal("key_free: key is NULL");
switch (k->type) {
case KEY_RSA1:
case KEY_RSA:
case KEY_RSA_CERT_V00:
case KEY_RSA_CERT:
if (k->rsa != NULL)
RSA_free(k->rsa);
k->rsa = NULL;
break;
case KEY_DSA:
case KEY_DSA_CERT_V00:
case KEY_DSA_CERT:
if (k->dsa != NULL)
DSA_free(k->dsa);
k->dsa = NULL;
break;
case KEY_ECDSA:
case KEY_ECDSA_CERT:
if (k->ecdsa != NULL)
EC_KEY_free(k->ecdsa);
k->ecdsa = NULL;
break;
case KEY_UNSPEC:
break;
default:
fatal("key_free: bad key type %d", k->type);
break;
}
if (key_is_cert(k)) {
if (k->cert != NULL)
cert_free(k->cert);
k->cert = NULL;
}
xfree(k);
}
static int
cert_compare(struct KeyCert *a, struct KeyCert *b)
{
if (a == NULL && b == NULL)
return 1;
if (a == NULL || b == NULL)
return 0;
if (buffer_len(&a->certblob) != buffer_len(&b->certblob))
return 0;
if (timingsafe_bcmp(buffer_ptr(&a->certblob), buffer_ptr(&b->certblob),
buffer_len(&a->certblob)) != 0)
return 0;
return 1;
}
/*
* Compare public portions of key only, allowing comparisons between
* certificates and plain keys too.
*/
int
key_equal_public(const Key *a, const Key *b)
{
BN_CTX *bnctx;
if (a == NULL || b == NULL ||
key_type_plain(a->type) != key_type_plain(b->type))
return 0;
switch (a->type) {
case KEY_RSA1:
case KEY_RSA_CERT_V00:
case KEY_RSA_CERT:
case KEY_RSA:
return a->rsa != NULL && b->rsa != NULL &&
BN_cmp(a->rsa->e, b->rsa->e) == 0 &&
BN_cmp(a->rsa->n, b->rsa->n) == 0;
case KEY_DSA_CERT_V00:
case KEY_DSA_CERT:
case KEY_DSA:
return a->dsa != NULL && b->dsa != NULL &&
BN_cmp(a->dsa->p, b->dsa->p) == 0 &&
BN_cmp(a->dsa->q, b->dsa->q) == 0 &&
BN_cmp(a->dsa->g, b->dsa->g) == 0 &&
BN_cmp(a->dsa->pub_key, b->dsa->pub_key) == 0;
case KEY_ECDSA_CERT:
case KEY_ECDSA:
if (a->ecdsa == NULL || b->ecdsa == NULL ||
EC_KEY_get0_public_key(a->ecdsa) == NULL ||
EC_KEY_get0_public_key(b->ecdsa) == NULL)
return 0;
if ((bnctx = BN_CTX_new()) == NULL)
fatal("%s: BN_CTX_new failed", __func__);
if (EC_GROUP_cmp(EC_KEY_get0_group(a->ecdsa),
EC_KEY_get0_group(b->ecdsa), bnctx) != 0 ||
EC_POINT_cmp(EC_KEY_get0_group(a->ecdsa),
EC_KEY_get0_public_key(a->ecdsa),
EC_KEY_get0_public_key(b->ecdsa), bnctx) != 0) {
BN_CTX_free(bnctx);
return 0;
}
BN_CTX_free(bnctx);
return 1;
default:
fatal("key_equal: bad key type %d", a->type);
}
/* NOTREACHED */
}
int
key_equal(const Key *a, const Key *b)
{
if (a == NULL || b == NULL || a->type != b->type)
return 0;
if (key_is_cert(a)) {
if (!cert_compare(a->cert, b->cert))
return 0;
}
return key_equal_public(a, b);
}
u_char*
key_fingerprint_raw(Key *k, enum fp_type dgst_type, u_int *dgst_raw_length)
{
const EVP_MD *md = NULL;
EVP_MD_CTX ctx;
u_char *blob = NULL;
u_char *retval = NULL;
u_int len = 0;
int nlen, elen, otype;
*dgst_raw_length = 0;
switch (dgst_type) {
case SSH_FP_MD5:
md = EVP_md5();
break;
case SSH_FP_SHA1:
md = EVP_sha1();
break;
default:
fatal("key_fingerprint_raw: bad digest type %d",
dgst_type);
}
switch (k->type) {
case KEY_RSA1:
nlen = BN_num_bytes(k->rsa->n);
elen = BN_num_bytes(k->rsa->e);
len = nlen + elen;
blob = xmalloc(len);
BN_bn2bin(k->rsa->n, blob);
BN_bn2bin(k->rsa->e, blob + nlen);
break;
case KEY_DSA:
case KEY_ECDSA:
case KEY_RSA:
key_to_blob(k, &blob, &len);
break;
case KEY_DSA_CERT_V00:
case KEY_RSA_CERT_V00:
case KEY_DSA_CERT:
case KEY_ECDSA_CERT:
case KEY_RSA_CERT:
/* We want a fingerprint of the _key_ not of the cert */
otype = k->type;
k->type = key_type_plain(k->type);
key_to_blob(k, &blob, &len);
k->type = otype;
break;
case KEY_UNSPEC:
return retval;
default:
fatal("key_fingerprint_raw: bad key type %d", k->type);
break;
}
if (blob != NULL) {
retval = xmalloc(EVP_MAX_MD_SIZE);
EVP_DigestInit(&ctx, md);
EVP_DigestUpdate(&ctx, blob, len);
EVP_DigestFinal(&ctx, retval, dgst_raw_length);
memset(blob, 0, len);
xfree(blob);
} else {
fatal("key_fingerprint_raw: blob is null");
}
return retval;
}
static char *
key_fingerprint_hex(u_char *dgst_raw, u_int dgst_raw_len)
{
char *retval;
u_int i;
retval = xcalloc(1, dgst_raw_len * 3 + 1);
for (i = 0; i < dgst_raw_len; i++) {
char hex[4];
snprintf(hex, sizeof(hex), "%02x:", dgst_raw[i]);
strlcat(retval, hex, dgst_raw_len * 3 + 1);
}
/* Remove the trailing ':' character */
retval[(dgst_raw_len * 3) - 1] = '\0';
return retval;
}
static char *
key_fingerprint_bubblebabble(u_char *dgst_raw, u_int dgst_raw_len)
{
char vowels[] = { 'a', 'e', 'i', 'o', 'u', 'y' };
char consonants[] = { 'b', 'c', 'd', 'f', 'g', 'h', 'k', 'l', 'm',
'n', 'p', 'r', 's', 't', 'v', 'z', 'x' };
u_int i, j = 0, rounds, seed = 1;
char *retval;
rounds = (dgst_raw_len / 2) + 1;
retval = xcalloc((rounds * 6), sizeof(char));
retval[j++] = 'x';
for (i = 0; i < rounds; i++) {
u_int idx0, idx1, idx2, idx3, idx4;
if ((i + 1 < rounds) || (dgst_raw_len % 2 != 0)) {
idx0 = (((((u_int)(dgst_raw[2 * i])) >> 6) & 3) +
seed) % 6;
idx1 = (((u_int)(dgst_raw[2 * i])) >> 2) & 15;
idx2 = ((((u_int)(dgst_raw[2 * i])) & 3) +
(seed / 6)) % 6;
retval[j++] = vowels[idx0];
retval[j++] = consonants[idx1];
retval[j++] = vowels[idx2];
if ((i + 1) < rounds) {
idx3 = (((u_int)(dgst_raw[(2 * i) + 1])) >> 4) & 15;
idx4 = (((u_int)(dgst_raw[(2 * i) + 1]))) & 15;
retval[j++] = consonants[idx3];
retval[j++] = '-';
retval[j++] = consonants[idx4];
seed = ((seed * 5) +
((((u_int)(dgst_raw[2 * i])) * 7) +
((u_int)(dgst_raw[(2 * i) + 1])))) % 36;
}
} else {
idx0 = seed % 6;
idx1 = 16;
idx2 = seed / 6;
retval[j++] = vowels[idx0];
retval[j++] = consonants[idx1];
retval[j++] = vowels[idx2];
}
}
retval[j++] = 'x';
retval[j++] = '\0';
return retval;
}
/*
* Draw an ASCII-Art representing the fingerprint so human brain can
* profit from its built-in pattern recognition ability.
* This technique is called "random art" and can be found in some
* scientific publications like this original paper:
*
* "Hash Visualization: a New Technique to improve Real-World Security",
* Perrig A. and Song D., 1999, International Workshop on Cryptographic
* Techniques and E-Commerce (CrypTEC '99)
* sparrow.ece.cmu.edu/~adrian/projects/validation/validation.pdf
*
* The subject came up in a talk by Dan Kaminsky, too.
*
* If you see the picture is different, the key is different.
* If the picture looks the same, you still know nothing.
*
* The algorithm used here is a worm crawling over a discrete plane,
* leaving a trace (augmenting the field) everywhere it goes.
* Movement is taken from dgst_raw 2bit-wise. Bumping into walls
* makes the respective movement vector be ignored for this turn.
* Graphs are not unambiguous, because circles in graphs can be
* walked in either direction.
*/
/*
* Field sizes for the random art. Have to be odd, so the starting point
* can be in the exact middle of the picture, and FLDBASE should be >=8 .
* Else pictures would be too dense, and drawing the frame would
* fail, too, because the key type would not fit in anymore.
*/
#define FLDBASE 8
#define FLDSIZE_Y (FLDBASE + 1)
#define FLDSIZE_X (FLDBASE * 2 + 1)
static char *
key_fingerprint_randomart(u_char *dgst_raw, u_int dgst_raw_len, const Key *k)
{
/*
* Chars to be used after each other every time the worm
* intersects with itself. Matter of taste.
*/
char *augmentation_string = " .o+=*BOX@%&#/^SE";
char *retval, *p;
u_char field[FLDSIZE_X][FLDSIZE_Y];
u_int i, b;
int x, y;
size_t len = strlen(augmentation_string) - 1;
retval = xcalloc(1, (FLDSIZE_X + 3) * (FLDSIZE_Y + 2));
/* initialize field */
memset(field, 0, FLDSIZE_X * FLDSIZE_Y * sizeof(char));
x = FLDSIZE_X / 2;
y = FLDSIZE_Y / 2;
/* process raw key */
for (i = 0; i < dgst_raw_len; i++) {
int input;
/* each byte conveys four 2-bit move commands */
input = dgst_raw[i];
for (b = 0; b < 4; b++) {
/* evaluate 2 bit, rest is shifted later */
x += (input & 0x1) ? 1 : -1;
y += (input & 0x2) ? 1 : -1;
/* assure we are still in bounds */
x = MAX(x, 0);
y = MAX(y, 0);
x = MIN(x, FLDSIZE_X - 1);
y = MIN(y, FLDSIZE_Y - 1);
/* augment the field */
if (field[x][y] < len - 2)
field[x][y]++;
input = input >> 2;
}
}
/* mark starting point and end point*/
field[FLDSIZE_X / 2][FLDSIZE_Y / 2] = len - 1;
field[x][y] = len;
/* fill in retval */
snprintf(retval, FLDSIZE_X, "+--[%4s %4u]", key_type(k), key_size(k));
p = strchr(retval, '\0');
/* output upper border */
for (i = p - retval - 1; i < FLDSIZE_X; i++)
*p++ = '-';
*p++ = '+';
*p++ = '\n';
/* output content */
for (y = 0; y < FLDSIZE_Y; y++) {
*p++ = '|';
for (x = 0; x < FLDSIZE_X; x++)
*p++ = augmentation_string[MIN(field[x][y], len)];
*p++ = '|';
*p++ = '\n';
}
/* output lower border */
*p++ = '+';
for (i = 0; i < FLDSIZE_X; i++)
*p++ = '-';
*p++ = '+';
return retval;
}
char *
key_fingerprint(Key *k, enum fp_type dgst_type, enum fp_rep dgst_rep)
{
char *retval = NULL;
u_char *dgst_raw;
u_int dgst_raw_len;
dgst_raw = key_fingerprint_raw(k, dgst_type, &dgst_raw_len);
if (!dgst_raw)
fatal("key_fingerprint: null from key_fingerprint_raw()");
switch (dgst_rep) {
case SSH_FP_HEX:
retval = key_fingerprint_hex(dgst_raw, dgst_raw_len);
break;
case SSH_FP_BUBBLEBABBLE:
retval = key_fingerprint_bubblebabble(dgst_raw, dgst_raw_len);
break;
case SSH_FP_RANDOMART:
retval = key_fingerprint_randomart(dgst_raw, dgst_raw_len, k);
break;
default:
fatal("key_fingerprint: bad digest representation %d",
dgst_rep);
break;
}
memset(dgst_raw, 0, dgst_raw_len);
xfree(dgst_raw);
return retval;
}
/*
* Reads a multiple-precision integer in decimal from the buffer, and advances
* the pointer. The integer must already be initialized. This function is
* permitted to modify the buffer. This leaves *cpp to point just beyond the
* last processed (and maybe modified) character. Note that this may modify
* the buffer containing the number.
*/
static int
read_bignum(char **cpp, BIGNUM * value)
{
char *cp = *cpp;
int old;
/* Skip any leading whitespace. */
for (; *cp == ' ' || *cp == '\t'; cp++)
;
/* Check that it begins with a decimal digit. */
if (*cp < '0' || *cp > '9')
return 0;
/* Save starting position. */
*cpp = cp;
/* Move forward until all decimal digits skipped. */
for (; *cp >= '0' && *cp <= '9'; cp++)
;
/* Save the old terminating character, and replace it by \0. */
old = *cp;
*cp = 0;
/* Parse the number. */
if (BN_dec2bn(&value, *cpp) == 0)
return 0;
/* Restore old terminating character. */
*cp = old;
/* Move beyond the number and return success. */
*cpp = cp;
return 1;
}
static int
write_bignum(FILE *f, BIGNUM *num)
{
char *buf = BN_bn2dec(num);
if (buf == NULL) {
error("write_bignum: BN_bn2dec() failed");
return 0;
}
fprintf(f, " %s", buf);
OPENSSL_free(buf);
return 1;
}
/* returns 1 ok, -1 error */
int
key_read(Key *ret, char **cpp)
{
Key *k;
int success = -1;
char *cp, *space;
int len, n, type, curve_nid = -1;
u_int bits;
u_char *blob;
cp = *cpp;
switch (ret->type) {
case KEY_RSA1:
/* Get number of bits. */
if (*cp < '0' || *cp > '9')
return -1; /* Bad bit count... */
for (bits = 0; *cp >= '0' && *cp <= '9'; cp++)
bits = 10 * bits + *cp - '0';
if (bits == 0)
return -1;
*cpp = cp;
/* Get public exponent, public modulus. */
if (!read_bignum(cpp, ret->rsa->e))
return -1;
if (!read_bignum(cpp, ret->rsa->n))
return -1;
/* validate the claimed number of bits */
if ((u_int)BN_num_bits(ret->rsa->n) != bits) {
verbose("key_read: claimed key size %d does not match "
"actual %d", bits, BN_num_bits(ret->rsa->n));
return -1;
}
success = 1;
break;
case KEY_UNSPEC:
case KEY_RSA:
case KEY_DSA:
case KEY_ECDSA:
case KEY_DSA_CERT_V00:
case KEY_RSA_CERT_V00:
case KEY_DSA_CERT:
case KEY_ECDSA_CERT:
case KEY_RSA_CERT:
space = strchr(cp, ' ');
if (space == NULL) {
debug3("key_read: missing whitespace");
return -1;
}
*space = '\0';
type = key_type_from_name(cp);
if (key_type_plain(type) == KEY_ECDSA &&
(curve_nid = key_ecdsa_nid_from_name(cp)) == -1) {
debug("key_read: invalid curve");
return -1;
}
*space = ' ';
if (type == KEY_UNSPEC) {
debug3("key_read: missing keytype");
return -1;
}
cp = space+1;
if (*cp == '\0') {
debug3("key_read: short string");
return -1;
}
if (ret->type == KEY_UNSPEC) {
ret->type = type;
} else if (ret->type != type) {
/* is a key, but different type */
debug3("key_read: type mismatch");
return -1;
}
len = 2*strlen(cp);
blob = xmalloc(len);
n = uudecode(cp, blob, len);
if (n < 0) {
error("key_read: uudecode %s failed", cp);
xfree(blob);
return -1;
}
k = key_from_blob(blob, (u_int)n);
xfree(blob);
if (k == NULL) {
error("key_read: key_from_blob %s failed", cp);
return -1;
}
if (k->type != type) {
error("key_read: type mismatch: encoding error");
key_free(k);
return -1;
}
if (key_type_plain(type) == KEY_ECDSA &&
curve_nid != k->ecdsa_nid) {
error("key_read: type mismatch: EC curve mismatch");
key_free(k);
return -1;
}
/*XXXX*/
if (key_is_cert(ret)) {
if (!key_is_cert(k)) {
error("key_read: loaded key is not a cert");
key_free(k);
return -1;
}
if (ret->cert != NULL)
cert_free(ret->cert);
ret->cert = k->cert;
k->cert = NULL;
}
if (key_type_plain(ret->type) == KEY_RSA) {
if (ret->rsa != NULL)
RSA_free(ret->rsa);
ret->rsa = k->rsa;
k->rsa = NULL;
#ifdef DEBUG_PK
RSA_print_fp(stderr, ret->rsa, 8);
#endif
}
if (key_type_plain(ret->type) == KEY_DSA) {
if (ret->dsa != NULL)
DSA_free(ret->dsa);
ret->dsa = k->dsa;
k->dsa = NULL;
#ifdef DEBUG_PK
DSA_print_fp(stderr, ret->dsa, 8);
#endif
}
if (key_type_plain(ret->type) == KEY_ECDSA) {
if (ret->ecdsa != NULL)
EC_KEY_free(ret->ecdsa);
ret->ecdsa = k->ecdsa;
ret->ecdsa_nid = k->ecdsa_nid;
k->ecdsa = NULL;
k->ecdsa_nid = -1;
#ifdef DEBUG_PK
key_dump_ec_key(ret->ecdsa);
#endif
}
success = 1;
/*XXXX*/
key_free(k);
if (success != 1)
break;
/* advance cp: skip whitespace and data */
while (*cp == ' ' || *cp == '\t')
cp++;
while (*cp != '\0' && *cp != ' ' && *cp != '\t')
cp++;
*cpp = cp;
break;
default:
fatal("key_read: bad key type: %d", ret->type);
break;
}
return success;
}
int
key_write(const Key *key, FILE *f)
{
int n, success = 0;
u_int len, bits = 0;
u_char *blob;
char *uu;
if (key_is_cert(key)) {
if (key->cert == NULL) {
error("%s: no cert data", __func__);
return 0;
}
if (buffer_len(&key->cert->certblob) == 0) {
error("%s: no signed certificate blob", __func__);
return 0;
}
}
switch (key->type) {
case KEY_RSA1:
if (key->rsa == NULL)
return 0;
/* size of modulus 'n' */
bits = BN_num_bits(key->rsa->n);
fprintf(f, "%u", bits);
if (write_bignum(f, key->rsa->e) &&
write_bignum(f, key->rsa->n))
return 1;
error("key_write: failed for RSA key");
return 0;
case KEY_DSA:
case KEY_DSA_CERT_V00:
case KEY_DSA_CERT:
if (key->dsa == NULL)
return 0;
break;
case KEY_ECDSA:
case KEY_ECDSA_CERT:
if (key->ecdsa == NULL)
return 0;
break;
case KEY_RSA:
case KEY_RSA_CERT_V00:
case KEY_RSA_CERT:
if (key->rsa == NULL)
return 0;
break;
default:
return 0;
}
key_to_blob(key, &blob, &len);
uu = xmalloc(2*len);
n = uuencode(blob, len, uu, 2*len);
if (n > 0) {
fprintf(f, "%s %s", key_ssh_name(key), uu);
success = 1;
}
xfree(blob);
xfree(uu);
return success;
}
const char *
key_type(const Key *k)
{
switch (k->type) {
case KEY_RSA1:
return "RSA1";
case KEY_RSA:
return "RSA";
case KEY_DSA:
return "DSA";
case KEY_ECDSA:
return "ECDSA";
case KEY_RSA_CERT_V00:
return "RSA-CERT-V00";
case KEY_DSA_CERT_V00:
return "DSA-CERT-V00";
case KEY_RSA_CERT:
return "RSA-CERT";
case KEY_DSA_CERT:
return "DSA-CERT";
case KEY_ECDSA_CERT:
return "ECDSA-CERT";
}
return "unknown";
}
const char *
key_cert_type(const Key *k)
{
switch (k->cert->type) {
case SSH2_CERT_TYPE_USER:
return "user";
case SSH2_CERT_TYPE_HOST:
return "host";
default:
return "unknown";
}
}
static const char *
key_ssh_name_from_type_nid(int type, int nid)
{
switch (type) {
case KEY_RSA:
return "ssh-rsa";
case KEY_DSA:
return "ssh-dss";
case KEY_RSA_CERT_V00:
return "ssh-rsa-cert-v00@openssh.com";
case KEY_DSA_CERT_V00:
return "ssh-dss-cert-v00@openssh.com";
case KEY_RSA_CERT:
return "ssh-rsa-cert-v01@openssh.com";
case KEY_DSA_CERT:
return "ssh-dss-cert-v01@openssh.com";
case KEY_ECDSA:
switch (nid) {
case NID_X9_62_prime256v1:
return "ecdsa-sha2-nistp256";
case NID_secp384r1:
return "ecdsa-sha2-nistp384";
case NID_secp521r1:
return "ecdsa-sha2-nistp521";
default:
break;
}
break;
case KEY_ECDSA_CERT:
switch (nid) {
case NID_X9_62_prime256v1:
return "ecdsa-sha2-nistp256-cert-v01@openssh.com";
case NID_secp384r1:
return "ecdsa-sha2-nistp384-cert-v01@openssh.com";
case NID_secp521r1:
return "ecdsa-sha2-nistp521-cert-v01@openssh.com";
default:
break;
}
break;
}
return "ssh-unknown";
}
const char *
key_ssh_name(const Key *k)
{
return key_ssh_name_from_type_nid(k->type, k->ecdsa_nid);
}
const char *
key_ssh_name_plain(const Key *k)
{
return key_ssh_name_from_type_nid(key_type_plain(k->type),
k->ecdsa_nid);
}
u_int
key_size(const Key *k)
{
switch (k->type) {
case KEY_RSA1:
case KEY_RSA:
case KEY_RSA_CERT_V00:
case KEY_RSA_CERT:
return BN_num_bits(k->rsa->n);
case KEY_DSA:
case KEY_DSA_CERT_V00:
case KEY_DSA_CERT:
return BN_num_bits(k->dsa->p);
case KEY_ECDSA:
case KEY_ECDSA_CERT:
return key_curve_nid_to_bits(k->ecdsa_nid);
}
return 0;
}
static RSA *
rsa_generate_private_key(u_int bits)
{
RSA *private;
private = RSA_generate_key(bits, RSA_F4, NULL, NULL);
if (private == NULL)
fatal("rsa_generate_private_key: key generation failed.");
return private;
}
static DSA*
dsa_generate_private_key(u_int bits)
{
DSA *private = DSA_generate_parameters(bits, NULL, 0, NULL, NULL, NULL, NULL);
if (private == NULL)
fatal("dsa_generate_private_key: DSA_generate_parameters failed");
if (!DSA_generate_key(private))
fatal("dsa_generate_private_key: DSA_generate_key failed.");
if (private == NULL)
fatal("dsa_generate_private_key: NULL.");
return private;
}
int
key_ecdsa_bits_to_nid(int bits)
{
switch (bits) {
case 256:
return NID_X9_62_prime256v1;
case 384:
return NID_secp384r1;
case 521:
return NID_secp521r1;
default:
return -1;
}
}
/*
* This is horrid, but OpenSSL's PEM_read_PrivateKey seems not to restore
* the EC_GROUP nid when loading a key...
*/
int
key_ecdsa_group_to_nid(const EC_GROUP *g)
{
EC_GROUP *eg;
int nids[] = {
NID_X9_62_prime256v1,
NID_secp384r1,
NID_secp521r1,
-1
};
u_int i;
BN_CTX *bnctx;
if ((bnctx = BN_CTX_new()) == NULL)
fatal("%s: BN_CTX_new() failed", __func__);
for (i = 0; nids[i] != -1; i++) {
if ((eg = EC_GROUP_new_by_curve_name(nids[i])) == NULL)
fatal("%s: EC_GROUP_new_by_curve_name failed",
__func__);
if (EC_GROUP_cmp(g, eg, bnctx) == 0) {
EC_GROUP_free(eg);
break;
}
EC_GROUP_free(eg);
}
BN_CTX_free(bnctx);
debug3("%s: nid = %d", __func__, nids[i]);
return nids[i];
}
static EC_KEY*
ecdsa_generate_private_key(u_int bits, int *nid)
{
EC_KEY *private;
if ((*nid = key_ecdsa_bits_to_nid(bits)) == -1)
fatal("%s: invalid key length", __func__);
if ((private = EC_KEY_new_by_curve_name(*nid)) == NULL)
fatal("%s: EC_KEY_new_by_curve_name failed", __func__);
if (EC_KEY_generate_key(private) != 1)
fatal("%s: EC_KEY_generate_key failed", __func__);
return private;
}
Key *
key_generate(int type, u_int bits)
{
Key *k = key_new(KEY_UNSPEC);
switch (type) {
case KEY_DSA:
k->dsa = dsa_generate_private_key(bits);
break;
case KEY_ECDSA:
k->ecdsa = ecdsa_generate_private_key(bits, &k->ecdsa_nid);
break;
case KEY_RSA:
case KEY_RSA1:
k->rsa = rsa_generate_private_key(bits);
break;
case KEY_RSA_CERT_V00:
case KEY_DSA_CERT_V00:
case KEY_RSA_CERT:
case KEY_DSA_CERT:
fatal("key_generate: cert keys cannot be generated directly");
default:
fatal("key_generate: unknown type %d", type);
}
k->type = type;
return k;
}
void
key_cert_copy(const Key *from_key, struct Key *to_key)
{
u_int i;
const struct KeyCert *from;
struct KeyCert *to;
if (to_key->cert != NULL) {
cert_free(to_key->cert);
to_key->cert = NULL;
}
if ((from = from_key->cert) == NULL)
return;
to = to_key->cert = cert_new();
buffer_append(&to->certblob, buffer_ptr(&from->certblob),
buffer_len(&from->certblob));
buffer_append(&to->critical,
buffer_ptr(&from->critical), buffer_len(&from->critical));
buffer_append(&to->extensions,
buffer_ptr(&from->extensions), buffer_len(&from->extensions));
to->serial = from->serial;
to->type = from->type;
to->key_id = from->key_id == NULL ? NULL : xstrdup(from->key_id);
to->valid_after = from->valid_after;
to->valid_before = from->valid_before;
to->signature_key = from->signature_key == NULL ?
NULL : key_from_private(from->signature_key);
to->nprincipals = from->nprincipals;
if (to->nprincipals > CERT_MAX_PRINCIPALS)
fatal("%s: nprincipals (%u) > CERT_MAX_PRINCIPALS (%u)",
__func__, to->nprincipals, CERT_MAX_PRINCIPALS);
if (to->nprincipals > 0) {
to->principals = xcalloc(from->nprincipals,
sizeof(*to->principals));
for (i = 0; i < to->nprincipals; i++)
to->principals[i] = xstrdup(from->principals[i]);
}
}
Key *
key_from_private(const Key *k)
{
Key *n = NULL;
switch (k->type) {
case KEY_DSA:
case KEY_DSA_CERT_V00:
case KEY_DSA_CERT:
n = key_new(k->type);
if ((BN_copy(n->dsa->p, k->dsa->p) == NULL) ||
(BN_copy(n->dsa->q, k->dsa->q) == NULL) ||
(BN_copy(n->dsa->g, k->dsa->g) == NULL) ||
(BN_copy(n->dsa->pub_key, k->dsa->pub_key) == NULL))
fatal("key_from_private: BN_copy failed");
break;
case KEY_ECDSA:
case KEY_ECDSA_CERT:
n = key_new(k->type);
n->ecdsa_nid = k->ecdsa_nid;
if ((n->ecdsa = EC_KEY_new_by_curve_name(k->ecdsa_nid)) == NULL)
fatal("%s: EC_KEY_new_by_curve_name failed", __func__);
if (EC_KEY_set_public_key(n->ecdsa,
EC_KEY_get0_public_key(k->ecdsa)) != 1)
fatal("%s: EC_KEY_set_public_key failed", __func__);
break;
case KEY_RSA:
case KEY_RSA1:
case KEY_RSA_CERT_V00:
case KEY_RSA_CERT:
n = key_new(k->type);
if ((BN_copy(n->rsa->n, k->rsa->n) == NULL) ||
(BN_copy(n->rsa->e, k->rsa->e) == NULL))
fatal("key_from_private: BN_copy failed");
break;
default:
fatal("key_from_private: unknown type %d", k->type);
break;
}
if (key_is_cert(k))
key_cert_copy(k, n);
return n;
}
int
key_type_from_name(char *name)
{
if (strcmp(name, "rsa1") == 0) {
return KEY_RSA1;
} else if (strcmp(name, "rsa") == 0) {
return KEY_RSA;
} else if (strcmp(name, "dsa") == 0) {
return KEY_DSA;
} else if (strcmp(name, "ssh-rsa") == 0) {
return KEY_RSA;
} else if (strcmp(name, "ssh-dss") == 0) {
return KEY_DSA;
} else if (strcmp(name, "ecdsa") == 0 ||
strcmp(name, "ecdsa-sha2-nistp256") == 0 ||
strcmp(name, "ecdsa-sha2-nistp384") == 0 ||
strcmp(name, "ecdsa-sha2-nistp521") == 0) {
return KEY_ECDSA;
} else if (strcmp(name, "ssh-rsa-cert-v00@openssh.com") == 0) {
return KEY_RSA_CERT_V00;
} else if (strcmp(name, "ssh-dss-cert-v00@openssh.com") == 0) {
return KEY_DSA_CERT_V00;
} else if (strcmp(name, "ssh-rsa-cert-v01@openssh.com") == 0) {
return KEY_RSA_CERT;
} else if (strcmp(name, "ssh-dss-cert-v01@openssh.com") == 0) {
return KEY_DSA_CERT;
} else if (strcmp(name, "ecdsa-sha2-nistp256-cert-v01@openssh.com") == 0 ||
strcmp(name, "ecdsa-sha2-nistp384-cert-v01@openssh.com") == 0 ||
strcmp(name, "ecdsa-sha2-nistp521-cert-v01@openssh.com") == 0)
return KEY_ECDSA_CERT;
debug2("key_type_from_name: unknown key type '%s'", name);
return KEY_UNSPEC;
}
int
key_ecdsa_nid_from_name(const char *name)
{
if (strcmp(name, "ecdsa-sha2-nistp256") == 0 ||
strcmp(name, "ecdsa-sha2-nistp256-cert-v01@openssh.com") == 0)
return NID_X9_62_prime256v1;
if (strcmp(name, "ecdsa-sha2-nistp384") == 0 ||
strcmp(name, "ecdsa-sha2-nistp384-cert-v01@openssh.com") == 0)
return NID_secp384r1;
if (strcmp(name, "ecdsa-sha2-nistp521") == 0 ||
strcmp(name, "ecdsa-sha2-nistp521-cert-v01@openssh.com") == 0)
return NID_secp521r1;
debug2("%s: unknown/non-ECDSA key type '%s'", __func__, name);
return -1;
}
int
key_names_valid2(const char *names)
{
char *s, *cp, *p;
if (names == NULL || strcmp(names, "") == 0)
return 0;
s = cp = xstrdup(names);
for ((p = strsep(&cp, ",")); p && *p != '\0';
(p = strsep(&cp, ","))) {
switch (key_type_from_name(p)) {
case KEY_RSA1:
case KEY_UNSPEC:
xfree(s);
return 0;
}
}
debug3("key names ok: [%s]", names);
xfree(s);
return 1;
}
static int
cert_parse(Buffer *b, Key *key, const u_char *blob, u_int blen)
{
u_char *principals, *critical, *exts, *sig_key, *sig;
u_int signed_len, plen, clen, sklen, slen, kidlen, elen;
Buffer tmp;
char *principal;
int ret = -1;
int v00 = key->type == KEY_DSA_CERT_V00 ||
key->type == KEY_RSA_CERT_V00;
buffer_init(&tmp);
/* Copy the entire key blob for verification and later serialisation */
buffer_append(&key->cert->certblob, blob, blen);
elen = 0; /* Not touched for v00 certs */
principals = exts = critical = sig_key = sig = NULL;
if ((!v00 && buffer_get_int64_ret(&key->cert->serial, b) != 0) ||
buffer_get_int_ret(&key->cert->type, b) != 0 ||
(key->cert->key_id = buffer_get_cstring_ret(b, &kidlen)) == NULL ||
(principals = buffer_get_string_ret(b, &plen)) == NULL ||
buffer_get_int64_ret(&key->cert->valid_after, b) != 0 ||
buffer_get_int64_ret(&key->cert->valid_before, b) != 0 ||
(critical = buffer_get_string_ret(b, &clen)) == NULL ||
(!v00 && (exts = buffer_get_string_ret(b, &elen)) == NULL) ||
(v00 && buffer_get_string_ptr_ret(b, NULL) == NULL) || /* nonce */
buffer_get_string_ptr_ret(b, NULL) == NULL || /* reserved */
(sig_key = buffer_get_string_ret(b, &sklen)) == NULL) {
error("%s: parse error", __func__);
goto out;
}
if (kidlen != strlen(key->cert->key_id)) {
error("%s: key ID contains \\0 character", __func__);
goto out;
}
/* Signature is left in the buffer so we can calculate this length */
signed_len = buffer_len(&key->cert->certblob) - buffer_len(b);
if ((sig = buffer_get_string_ret(b, &slen)) == NULL) {
error("%s: parse error", __func__);
goto out;
}
if (key->cert->type != SSH2_CERT_TYPE_USER &&
key->cert->type != SSH2_CERT_TYPE_HOST) {
error("Unknown certificate type %u", key->cert->type);
goto out;
}
buffer_append(&tmp, principals, plen);
while (buffer_len(&tmp) > 0) {
if (key->cert->nprincipals >= CERT_MAX_PRINCIPALS) {
error("%s: Too many principals", __func__);
goto out;
}
if ((principal = buffer_get_cstring_ret(&tmp, &plen)) == NULL) {
error("%s: Principals data invalid", __func__);
goto out;
}
key->cert->principals = xrealloc(key->cert->principals,
key->cert->nprincipals + 1, sizeof(*key->cert->principals));
key->cert->principals[key->cert->nprincipals++] = principal;
}
buffer_clear(&tmp);
buffer_append(&key->cert->critical, critical, clen);
buffer_append(&tmp, critical, clen);
/* validate structure */
while (buffer_len(&tmp) != 0) {
if (buffer_get_string_ptr_ret(&tmp, NULL) == NULL ||
buffer_get_string_ptr_ret(&tmp, NULL) == NULL) {
error("%s: critical option data invalid", __func__);
goto out;
}
}
buffer_clear(&tmp);
buffer_append(&key->cert->extensions, exts, elen);
buffer_append(&tmp, exts, elen);
/* validate structure */
while (buffer_len(&tmp) != 0) {
if (buffer_get_string_ptr_ret(&tmp, NULL) == NULL ||
buffer_get_string_ptr_ret(&tmp, NULL) == NULL) {
error("%s: extension data invalid", __func__);
goto out;
}
}
buffer_clear(&tmp);
if ((key->cert->signature_key = key_from_blob(sig_key,
sklen)) == NULL) {
error("%s: Signature key invalid", __func__);
goto out;
}
if (key->cert->signature_key->type != KEY_RSA &&
key->cert->signature_key->type != KEY_DSA &&
key->cert->signature_key->type != KEY_ECDSA) {
error("%s: Invalid signature key type %s (%d)", __func__,
key_type(key->cert->signature_key),
key->cert->signature_key->type);
goto out;
}
switch (key_verify(key->cert->signature_key, sig, slen,
buffer_ptr(&key->cert->certblob), signed_len)) {
case 1:
ret = 0;
break; /* Good signature */
case 0:
error("%s: Invalid signature on certificate", __func__);
goto out;
case -1:
error("%s: Certificate signature verification failed",
__func__);
goto out;
}
out:
buffer_free(&tmp);
if (principals != NULL)
xfree(principals);
if (critical != NULL)
xfree(critical);
if (exts != NULL)
xfree(exts);
if (sig_key != NULL)
xfree(sig_key);
if (sig != NULL)
xfree(sig);
return ret;
}
Key *
key_from_blob(const u_char *blob, u_int blen)
{
Buffer b;
int rlen, type, nid = -1;
char *ktype = NULL, *curve = NULL;
Key *key = NULL;
EC_POINT *q = NULL;
#ifdef DEBUG_PK
dump_base64(stderr, blob, blen);
#endif
buffer_init(&b);
buffer_append(&b, blob, blen);
if ((ktype = buffer_get_cstring_ret(&b, NULL)) == NULL) {
error("key_from_blob: can't read key type");
goto out;
}
type = key_type_from_name(ktype);
if (key_type_plain(type) == KEY_ECDSA)
nid = key_ecdsa_nid_from_name(ktype);
switch (type) {
case KEY_RSA_CERT:
(void)buffer_get_string_ptr_ret(&b, NULL); /* Skip nonce */
/* FALLTHROUGH */
case KEY_RSA:
case KEY_RSA_CERT_V00:
key = key_new(type);
if (buffer_get_bignum2_ret(&b, key->rsa->e) == -1 ||
buffer_get_bignum2_ret(&b, key->rsa->n) == -1) {
error("key_from_blob: can't read rsa key");
badkey:
key_free(key);
key = NULL;
goto out;
}
#ifdef DEBUG_PK
RSA_print_fp(stderr, key->rsa, 8);
#endif
break;
case KEY_DSA_CERT:
(void)buffer_get_string_ptr_ret(&b, NULL); /* Skip nonce */
/* FALLTHROUGH */
case KEY_DSA:
case KEY_DSA_CERT_V00:
key = key_new(type);
if (buffer_get_bignum2_ret(&b, key->dsa->p) == -1 ||
buffer_get_bignum2_ret(&b, key->dsa->q) == -1 ||
buffer_get_bignum2_ret(&b, key->dsa->g) == -1 ||
buffer_get_bignum2_ret(&b, key->dsa->pub_key) == -1) {
error("key_from_blob: can't read dsa key");
goto badkey;
}
#ifdef DEBUG_PK
DSA_print_fp(stderr, key->dsa, 8);
#endif
break;
case KEY_ECDSA_CERT:
(void)buffer_get_string_ptr_ret(&b, NULL); /* Skip nonce */
/* FALLTHROUGH */
case KEY_ECDSA:
key = key_new(type);
key->ecdsa_nid = nid;
if ((curve = buffer_get_string_ret(&b, NULL)) == NULL) {
error("key_from_blob: can't read ecdsa curve");
goto badkey;
}
if (key->ecdsa_nid != key_curve_name_to_nid(curve)) {
error("key_from_blob: ecdsa curve doesn't match type");
goto badkey;
}
if (key->ecdsa != NULL)
EC_KEY_free(key->ecdsa);
if ((key->ecdsa = EC_KEY_new_by_curve_name(key->ecdsa_nid))
== NULL)
fatal("key_from_blob: EC_KEY_new_by_curve_name failed");
if ((q = EC_POINT_new(EC_KEY_get0_group(key->ecdsa))) == NULL)
fatal("key_from_blob: EC_POINT_new failed");
if (buffer_get_ecpoint_ret(&b, EC_KEY_get0_group(key->ecdsa),
q) == -1) {
error("key_from_blob: can't read ecdsa key point");
goto badkey;
}
if (key_ec_validate_public(EC_KEY_get0_group(key->ecdsa),
q) != 0)
goto badkey;
if (EC_KEY_set_public_key(key->ecdsa, q) != 1)
fatal("key_from_blob: EC_KEY_set_public_key failed");
#ifdef DEBUG_PK
key_dump_ec_point(EC_KEY_get0_group(key->ecdsa), q);
#endif
break;
case KEY_UNSPEC:
key = key_new(type);
break;
default:
error("key_from_blob: cannot handle type %s", ktype);
goto out;
}
if (key_is_cert(key) && cert_parse(&b, key, blob, blen) == -1) {
error("key_from_blob: can't parse cert data");
goto badkey;
}
rlen = buffer_len(&b);
if (key != NULL && rlen != 0)
error("key_from_blob: remaining bytes in key blob %d", rlen);
out:
if (ktype != NULL)
xfree(ktype);
if (curve != NULL)
xfree(curve);
if (q != NULL)
EC_POINT_free(q);
buffer_free(&b);
return key;
}
int
key_to_blob(const Key *key, u_char **blobp, u_int *lenp)
{
Buffer b;
int len;
if (key == NULL) {
error("key_to_blob: key == NULL");
return 0;
}
buffer_init(&b);
switch (key->type) {
case KEY_DSA_CERT_V00:
case KEY_RSA_CERT_V00:
case KEY_DSA_CERT:
case KEY_ECDSA_CERT:
case KEY_RSA_CERT:
/* Use the existing blob */
buffer_append(&b, buffer_ptr(&key->cert->certblob),
buffer_len(&key->cert->certblob));
break;
case KEY_DSA:
buffer_put_cstring(&b, key_ssh_name(key));
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);
break;
case KEY_ECDSA:
buffer_put_cstring(&b, key_ssh_name(key));
buffer_put_cstring(&b, key_curve_nid_to_name(key->ecdsa_nid));
buffer_put_ecpoint(&b, EC_KEY_get0_group(key->ecdsa),
EC_KEY_get0_public_key(key->ecdsa));
break;
case KEY_RSA:
buffer_put_cstring(&b, key_ssh_name(key));
buffer_put_bignum2(&b, key->rsa->e);
buffer_put_bignum2(&b, key->rsa->n);
break;
default:
error("key_to_blob: unsupported key type %d", key->type);
buffer_free(&b);
return 0;
}
len = buffer_len(&b);
if (lenp != NULL)
*lenp = len;
if (blobp != NULL) {
*blobp = xmalloc(len);
memcpy(*blobp, buffer_ptr(&b), len);
}
memset(buffer_ptr(&b), 0, len);
buffer_free(&b);
return len;
}
int
key_sign(
const Key *key,
u_char **sigp, u_int *lenp,
const u_char *data, u_int datalen)
{
switch (key->type) {
case KEY_DSA_CERT_V00:
case KEY_DSA_CERT:
case KEY_DSA:
return ssh_dss_sign(key, sigp, lenp, data, datalen);
case KEY_ECDSA_CERT:
case KEY_ECDSA:
return ssh_ecdsa_sign(key, sigp, lenp, data, datalen);
case KEY_RSA_CERT_V00:
case KEY_RSA_CERT:
case KEY_RSA:
return ssh_rsa_sign(key, sigp, lenp, data, datalen);
default:
error("key_sign: invalid key type %d", key->type);
return -1;
}
}
/*
* key_verify returns 1 for a correct signature, 0 for an incorrect signature
* and -1 on error.
*/
int
key_verify(
const Key *key,
const u_char *signature, u_int signaturelen,
const u_char *data, u_int datalen)
{
if (signaturelen == 0)
return -1;
switch (key->type) {
case KEY_DSA_CERT_V00:
case KEY_DSA_CERT:
case KEY_DSA:
return ssh_dss_verify(key, signature, signaturelen, data, datalen);
case KEY_ECDSA_CERT:
case KEY_ECDSA:
return ssh_ecdsa_verify(key, signature, signaturelen, data, datalen);
case KEY_RSA_CERT_V00:
case KEY_RSA_CERT:
case KEY_RSA:
return ssh_rsa_verify(key, signature, signaturelen, data, datalen);
default:
error("key_verify: invalid key type %d", key->type);
return -1;
}
}
/* Converts a private to a public key */
Key *
key_demote(const Key *k)
{
Key *pk;
pk = xcalloc(1, sizeof(*pk));
pk->type = k->type;
pk->flags = k->flags;
pk->ecdsa_nid = k->ecdsa_nid;
pk->dsa = NULL;
pk->ecdsa = NULL;
pk->rsa = NULL;
switch (k->type) {
case KEY_RSA_CERT_V00:
case KEY_RSA_CERT:
key_cert_copy(k, pk);
/* FALLTHROUGH */
case KEY_RSA1:
case KEY_RSA:
if ((pk->rsa = RSA_new()) == NULL)
fatal("key_demote: RSA_new failed");
if ((pk->rsa->e = BN_dup(k->rsa->e)) == NULL)
fatal("key_demote: BN_dup failed");
if ((pk->rsa->n = BN_dup(k->rsa->n)) == NULL)
fatal("key_demote: BN_dup failed");
break;
case KEY_DSA_CERT_V00:
case KEY_DSA_CERT:
key_cert_copy(k, pk);
/* FALLTHROUGH */
case KEY_DSA:
if ((pk->dsa = DSA_new()) == NULL)
fatal("key_demote: DSA_new failed");
if ((pk->dsa->p = BN_dup(k->dsa->p)) == NULL)
fatal("key_demote: BN_dup failed");
if ((pk->dsa->q = BN_dup(k->dsa->q)) == NULL)
fatal("key_demote: BN_dup failed");
if ((pk->dsa->g = BN_dup(k->dsa->g)) == NULL)
fatal("key_demote: BN_dup failed");
if ((pk->dsa->pub_key = BN_dup(k->dsa->pub_key)) == NULL)
fatal("key_demote: BN_dup failed");
break;
case KEY_ECDSA_CERT:
key_cert_copy(k, pk);
/* FALLTHROUGH */
case KEY_ECDSA:
if ((pk->ecdsa = EC_KEY_new_by_curve_name(pk->ecdsa_nid)) == NULL)
fatal("key_demote: EC_KEY_new_by_curve_name failed");
if (EC_KEY_set_public_key(pk->ecdsa,
EC_KEY_get0_public_key(k->ecdsa)) != 1)
fatal("key_demote: EC_KEY_set_public_key failed");
break;
default:
fatal("key_free: bad key type %d", k->type);
break;
}
return (pk);
}
int
key_is_cert(const Key *k)
{
if (k == NULL)
return 0;
switch (k->type) {
case KEY_RSA_CERT_V00:
case KEY_DSA_CERT_V00:
case KEY_RSA_CERT:
case KEY_DSA_CERT:
case KEY_ECDSA_CERT:
return 1;
default:
return 0;
}
}
/* Return the cert-less equivalent to a certified key type */
int
key_type_plain(int type)
{
switch (type) {
case KEY_RSA_CERT_V00:
case KEY_RSA_CERT:
return KEY_RSA;
case KEY_DSA_CERT_V00:
case KEY_DSA_CERT:
return KEY_DSA;
case KEY_ECDSA_CERT:
return KEY_ECDSA;
default:
return type;
}
}
/* Convert a KEY_RSA or KEY_DSA to their _CERT equivalent */
int
key_to_certified(Key *k, int legacy)
{
switch (k->type) {
case KEY_RSA:
k->cert = cert_new();
k->type = legacy ? KEY_RSA_CERT_V00 : KEY_RSA_CERT;
return 0;
case KEY_DSA:
k->cert = cert_new();
k->type = legacy ? KEY_DSA_CERT_V00 : KEY_DSA_CERT;
return 0;
case KEY_ECDSA:
k->cert = cert_new();
k->type = KEY_ECDSA_CERT;
return 0;
default:
error("%s: key has incorrect type %s", __func__, key_type(k));
return -1;
}
}
/* Convert a KEY_RSA_CERT or KEY_DSA_CERT to their raw key equivalent */
int
key_drop_cert(Key *k)
{
switch (k->type) {
case KEY_RSA_CERT_V00:
case KEY_RSA_CERT:
cert_free(k->cert);
k->type = KEY_RSA;
return 0;
case KEY_DSA_CERT_V00:
case KEY_DSA_CERT:
cert_free(k->cert);
k->type = KEY_DSA;
return 0;
case KEY_ECDSA_CERT:
cert_free(k->cert);
k->type = KEY_ECDSA;
return 0;
default:
error("%s: key has incorrect type %s", __func__, key_type(k));
return -1;
}
}
/*
* Sign a KEY_RSA_CERT, KEY_DSA_CERT or KEY_ECDSA_CERT, (re-)generating
* the signed certblob
*/
int
key_certify(Key *k, Key *ca)
{
Buffer principals;
u_char *ca_blob, *sig_blob, nonce[32];
u_int i, ca_len, sig_len;
if (k->cert == NULL) {
error("%s: key lacks cert info", __func__);
return -1;
}
if (!key_is_cert(k)) {
error("%s: certificate has unknown type %d", __func__,
k->cert->type);
return -1;
}
if (ca->type != KEY_RSA && ca->type != KEY_DSA &&
ca->type != KEY_ECDSA) {
error("%s: CA key has unsupported type %s", __func__,
key_type(ca));
return -1;
}
key_to_blob(ca, &ca_blob, &ca_len);
buffer_clear(&k->cert->certblob);
buffer_put_cstring(&k->cert->certblob, key_ssh_name(k));
/* -v01 certs put nonce first */
if (!key_cert_is_legacy(k)) {
arc4random_buf(&nonce, sizeof(nonce));
buffer_put_string(&k->cert->certblob, nonce, sizeof(nonce));
}
switch (k->type) {
case KEY_DSA_CERT_V00:
case KEY_DSA_CERT:
buffer_put_bignum2(&k->cert->certblob, k->dsa->p);
buffer_put_bignum2(&k->cert->certblob, k->dsa->q);
buffer_put_bignum2(&k->cert->certblob, k->dsa->g);
buffer_put_bignum2(&k->cert->certblob, k->dsa->pub_key);
break;
case KEY_ECDSA_CERT:
buffer_put_cstring(&k->cert->certblob,
key_curve_nid_to_name(k->ecdsa_nid));
buffer_put_ecpoint(&k->cert->certblob,
EC_KEY_get0_group(k->ecdsa),
EC_KEY_get0_public_key(k->ecdsa));
break;
case KEY_RSA_CERT_V00:
case KEY_RSA_CERT:
buffer_put_bignum2(&k->cert->certblob, k->rsa->e);
buffer_put_bignum2(&k->cert->certblob, k->rsa->n);
break;
default:
error("%s: key has incorrect type %s", __func__, key_type(k));
buffer_clear(&k->cert->certblob);
xfree(ca_blob);
return -1;
}
/* -v01 certs have a serial number next */
if (!key_cert_is_legacy(k))
buffer_put_int64(&k->cert->certblob, k->cert->serial);
buffer_put_int(&k->cert->certblob, k->cert->type);
buffer_put_cstring(&k->cert->certblob, k->cert->key_id);
buffer_init(&principals);
for (i = 0; i < k->cert->nprincipals; i++)
buffer_put_cstring(&principals, k->cert->principals[i]);
buffer_put_string(&k->cert->certblob, buffer_ptr(&principals),
buffer_len(&principals));
buffer_free(&principals);
buffer_put_int64(&k->cert->certblob, k->cert->valid_after);
buffer_put_int64(&k->cert->certblob, k->cert->valid_before);
buffer_put_string(&k->cert->certblob,
buffer_ptr(&k->cert->critical), buffer_len(&k->cert->critical));
/* -v01 certs have non-critical options here */
if (!key_cert_is_legacy(k)) {
buffer_put_string(&k->cert->certblob,
buffer_ptr(&k->cert->extensions),
buffer_len(&k->cert->extensions));
}
/* -v00 certs put the nonce at the end */
if (key_cert_is_legacy(k))
buffer_put_string(&k->cert->certblob, nonce, sizeof(nonce));
buffer_put_string(&k->cert->certblob, NULL, 0); /* reserved */
buffer_put_string(&k->cert->certblob, ca_blob, ca_len);
xfree(ca_blob);
/* Sign the whole mess */
if (key_sign(ca, &sig_blob, &sig_len, buffer_ptr(&k->cert->certblob),
buffer_len(&k->cert->certblob)) != 0) {
error("%s: signature operation failed", __func__);
buffer_clear(&k->cert->certblob);
return -1;
}
/* Append signature and we are done */
buffer_put_string(&k->cert->certblob, sig_blob, sig_len);
xfree(sig_blob);
return 0;
}
int
key_cert_check_authority(const Key *k, int want_host, int require_principal,
const char *name, const char **reason)
{
u_int i, principal_matches;
time_t now = time(NULL);
if (want_host) {
if (k->cert->type != SSH2_CERT_TYPE_HOST) {
*reason = "Certificate invalid: not a host certificate";
return -1;
}
} else {
if (k->cert->type != SSH2_CERT_TYPE_USER) {
*reason = "Certificate invalid: not a user certificate";
return -1;
}
}
if (now < 0) {
error("%s: system clock lies before epoch", __func__);
*reason = "Certificate invalid: not yet valid";
return -1;
}
if ((u_int64_t)now < k->cert->valid_after) {
*reason = "Certificate invalid: not yet valid";
return -1;
}
if ((u_int64_t)now >= k->cert->valid_before) {
*reason = "Certificate invalid: expired";
return -1;
}
if (k->cert->nprincipals == 0) {
if (require_principal) {
*reason = "Certificate lacks principal list";
return -1;
}
} else if (name != NULL) {
principal_matches = 0;
for (i = 0; i < k->cert->nprincipals; i++) {
if (strcmp(name, k->cert->principals[i]) == 0) {
principal_matches = 1;
break;
}
}
if (!principal_matches) {
*reason = "Certificate invalid: name is not a listed "
"principal";
return -1;
}
}
return 0;
}
int
key_cert_is_legacy(Key *k)
{
switch (k->type) {
case KEY_DSA_CERT_V00:
case KEY_RSA_CERT_V00:
return 1;
default:
return 0;
}
}
/* XXX: these are really begging for a table-driven approach */
int
key_curve_name_to_nid(const char *name)
{
if (strcmp(name, "nistp256") == 0)
return NID_X9_62_prime256v1;
else if (strcmp(name, "nistp384") == 0)
return NID_secp384r1;
else if (strcmp(name, "nistp521") == 0)
return NID_secp521r1;
debug("%s: unsupported EC curve name \"%.100s\"", __func__, name);
return -1;
}
u_int
key_curve_nid_to_bits(int nid)
{
switch (nid) {
case NID_X9_62_prime256v1:
return 256;
case NID_secp384r1:
return 384;
case NID_secp521r1:
return 521;
default:
error("%s: unsupported EC curve nid %d", __func__, nid);
return 0;
}
}
const char *
key_curve_nid_to_name(int nid)
{
if (nid == NID_X9_62_prime256v1)
return "nistp256";
else if (nid == NID_secp384r1)
return "nistp384";
else if (nid == NID_secp521r1)
return "nistp521";
error("%s: unsupported EC curve nid %d", __func__, nid);
return NULL;
}
const EVP_MD *
key_ec_nid_to_evpmd(int nid)
{
int kbits = key_curve_nid_to_bits(nid);
if (kbits == 0)
fatal("%s: invalid nid %d", __func__, nid);
/* RFC5656 section 6.2.1 */
if (kbits <= 256)
return EVP_sha256();
else if (kbits <= 384)
return EVP_sha384();
else
return EVP_sha512();
}
int
key_ec_validate_public(const EC_GROUP *group, const EC_POINT *public)
{
BN_CTX *bnctx;
EC_POINT *nq = NULL;
BIGNUM *order, *x, *y, *tmp;
int ret = -1;
if ((bnctx = BN_CTX_new()) == NULL)
fatal("%s: BN_CTX_new failed", __func__);
BN_CTX_start(bnctx);
/*
* We shouldn't ever hit this case because bignum_get_ecpoint()
* refuses to load GF2m points.
*/
if (EC_METHOD_get_field_type(EC_GROUP_method_of(group)) !=
NID_X9_62_prime_field) {
error("%s: group is not a prime field", __func__);
goto out;
}
/* Q != infinity */
if (EC_POINT_is_at_infinity(group, public)) {
error("%s: received degenerate public key (infinity)",
__func__);
goto out;
}
if ((x = BN_CTX_get(bnctx)) == NULL ||
(y = BN_CTX_get(bnctx)) == NULL ||
(order = BN_CTX_get(bnctx)) == NULL ||
(tmp = BN_CTX_get(bnctx)) == NULL)
fatal("%s: BN_CTX_get failed", __func__);
/* log2(x) > log2(order)/2, log2(y) > log2(order)/2 */
if (EC_GROUP_get_order(group, order, bnctx) != 1)
fatal("%s: EC_GROUP_get_order failed", __func__);
if (EC_POINT_get_affine_coordinates_GFp(group, public,
x, y, bnctx) != 1)
fatal("%s: EC_POINT_get_affine_coordinates_GFp", __func__);
if (BN_num_bits(x) <= BN_num_bits(order) / 2) {
error("%s: public key x coordinate too small: "
"bits(x) = %d, bits(order)/2 = %d", __func__,
BN_num_bits(x), BN_num_bits(order) / 2);
goto out;
}
if (BN_num_bits(y) <= BN_num_bits(order) / 2) {
error("%s: public key y coordinate too small: "
"bits(y) = %d, bits(order)/2 = %d", __func__,
BN_num_bits(x), BN_num_bits(order) / 2);
goto out;
}
/* nQ == infinity (n == order of subgroup) */
if ((nq = EC_POINT_new(group)) == NULL)
fatal("%s: BN_CTX_tmp failed", __func__);
if (EC_POINT_mul(group, nq, NULL, public, order, bnctx) != 1)
fatal("%s: EC_GROUP_mul failed", __func__);
if (EC_POINT_is_at_infinity(group, nq) != 1) {
error("%s: received degenerate public key (nQ != infinity)",
__func__);
goto out;
}
/* x < order - 1, y < order - 1 */
if (!BN_sub(tmp, order, BN_value_one()))
fatal("%s: BN_sub failed", __func__);
if (BN_cmp(x, tmp) >= 0) {
error("%s: public key x coordinate >= group order - 1",
__func__);
goto out;
}
if (BN_cmp(y, tmp) >= 0) {
error("%s: public key y coordinate >= group order - 1",
__func__);
goto out;
}
ret = 0;
out:
BN_CTX_free(bnctx);
EC_POINT_free(nq);
return ret;
}
int
key_ec_validate_private(const EC_KEY *key)
{
BN_CTX *bnctx;
BIGNUM *order, *tmp;
int ret = -1;
if ((bnctx = BN_CTX_new()) == NULL)
fatal("%s: BN_CTX_new failed", __func__);
BN_CTX_start(bnctx);
if ((order = BN_CTX_get(bnctx)) == NULL ||
(tmp = BN_CTX_get(bnctx)) == NULL)
fatal("%s: BN_CTX_get failed", __func__);
/* log2(private) > log2(order)/2 */
if (EC_GROUP_get_order(EC_KEY_get0_group(key), order, bnctx) != 1)
fatal("%s: EC_GROUP_get_order failed", __func__);
if (BN_num_bits(EC_KEY_get0_private_key(key)) <=
BN_num_bits(order) / 2) {
error("%s: private key too small: "
"bits(y) = %d, bits(order)/2 = %d", __func__,
BN_num_bits(EC_KEY_get0_private_key(key)),
BN_num_bits(order) / 2);
goto out;
}
/* private < order - 1 */
if (!BN_sub(tmp, order, BN_value_one()))
fatal("%s: BN_sub failed", __func__);
if (BN_cmp(EC_KEY_get0_private_key(key), tmp) >= 0) {
error("%s: private key >= group order - 1", __func__);
goto out;
}
ret = 0;
out:
BN_CTX_free(bnctx);
return ret;
}
#if defined(DEBUG_KEXECDH) || defined(DEBUG_PK)
void
key_dump_ec_point(const EC_GROUP *group, const EC_POINT *point)
{
BIGNUM *x, *y;
BN_CTX *bnctx;
if (point == NULL) {
fputs("point=(NULL)\n", stderr);
return;
}
if ((bnctx = BN_CTX_new()) == NULL)
fatal("%s: BN_CTX_new failed", __func__);
BN_CTX_start(bnctx);
if ((x = BN_CTX_get(bnctx)) == NULL || (y = BN_CTX_get(bnctx)) == NULL)
fatal("%s: BN_CTX_get failed", __func__);
if (EC_METHOD_get_field_type(EC_GROUP_method_of(group)) !=
NID_X9_62_prime_field)
fatal("%s: group is not a prime field", __func__);
if (EC_POINT_get_affine_coordinates_GFp(group, point, x, y, bnctx) != 1)
fatal("%s: EC_POINT_get_affine_coordinates_GFp", __func__);
fputs("x=", stderr);
BN_print_fp(stderr, x);
fputs("\ny=", stderr);
BN_print_fp(stderr, y);
fputs("\n", stderr);
BN_CTX_free(bnctx);
}
void
key_dump_ec_key(const EC_KEY *key)
{
const BIGNUM *exponent;
key_dump_ec_point(EC_KEY_get0_group(key), EC_KEY_get0_public_key(key));
fputs("exponent=", stderr);
if ((exponent = EC_KEY_get0_private_key(key)) == NULL)
fputs("(NULL)", stderr);
else
BN_print_fp(stderr, EC_KEY_get0_private_key(key));
fputs("\n", stderr);
}
#endif /* defined(DEBUG_KEXECDH) || defined(DEBUG_PK) */
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