int
key_sign(const Key *key, u_char **sigp, u_int *lenp,
const u_char *data, u_int datalen)
{
int r;
u_char *sig;
size_t siglen;
if (sigp != NULL)
*sigp = NULL;
if (lenp != NULL)
*lenp = 0;
if ((r = sshkey_sign(key, &sig, &siglen,
data, datalen, datafellows)) != 0) {
fatal_on_fatal_errors(r, __func__, 0);
error("%s: %s", __func__, ssh_err(r));
return -1;
}
if (siglen > INT_MAX)
fatal("%s: giant len %zu", __func__, siglen);
if (sigp != NULL)
*sigp = sig;
if (lenp != NULL)
*lenp = siglen;
return 0;
}
static void
build_cert(struct sshbuf *b, const struct sshkey *k, const char *type,
const struct sshkey *sign_key, const struct sshkey *ca_key,
const char *sig_alg)
{
struct sshbuf *ca_buf, *pk, *principals, *critopts, *exts;
u_char *sigblob;
size_t siglen;
ca_buf = sshbuf_new();
ASSERT_PTR_NE(ca_buf, NULL);
ASSERT_INT_EQ(sshkey_putb(ca_key, ca_buf), 0);
/*
* Get the public key serialisation by rendering the key and skipping
* the type string. This is a bit of a hack :/
*/
pk = sshbuf_new();
ASSERT_PTR_NE(pk, NULL);
ASSERT_INT_EQ(sshkey_putb_plain(k, pk), 0);
ASSERT_INT_EQ(sshbuf_skip_string(pk), 0);
principals = sshbuf_new();
ASSERT_PTR_NE(principals, NULL);
ASSERT_INT_EQ(sshbuf_put_cstring(principals, "gsamsa"), 0);
ASSERT_INT_EQ(sshbuf_put_cstring(principals, "gregor"), 0);
critopts = sshbuf_new();
ASSERT_PTR_NE(critopts, NULL);
put_opt(critopts, "force-command", "/usr/local/bin/nethack");
put_opt(critopts, "source-address", "192.168.0.0/24,127.0.0.1,::1");
exts = sshbuf_new();
ASSERT_PTR_NE(exts, NULL);
put_opt(critopts, "permit-X11-forwarding", NULL);
ASSERT_INT_EQ(sshbuf_put_cstring(b, type), 0);
ASSERT_INT_EQ(sshbuf_put_cstring(b, "noncenoncenonce!"), 0); /* nonce */
ASSERT_INT_EQ(sshbuf_putb(b, pk), 0); /* public key serialisation */
ASSERT_INT_EQ(sshbuf_put_u64(b, 1234), 0); /* serial */
ASSERT_INT_EQ(sshbuf_put_u32(b, SSH2_CERT_TYPE_USER), 0); /* type */
ASSERT_INT_EQ(sshbuf_put_cstring(b, "gregor"), 0); /* key ID */
ASSERT_INT_EQ(sshbuf_put_stringb(b, principals), 0); /* principals */
ASSERT_INT_EQ(sshbuf_put_u64(b, 0), 0); /* start */
ASSERT_INT_EQ(sshbuf_put_u64(b, 0xffffffffffffffffULL), 0); /* end */
ASSERT_INT_EQ(sshbuf_put_stringb(b, critopts), 0); /* options */
ASSERT_INT_EQ(sshbuf_put_stringb(b, exts), 0); /* extensions */
ASSERT_INT_EQ(sshbuf_put_string(b, NULL, 0), 0); /* reserved */
ASSERT_INT_EQ(sshbuf_put_stringb(b, ca_buf), 0); /* signature key */
ASSERT_INT_EQ(sshkey_sign(sign_key, &sigblob, &siglen,
sshbuf_ptr(b), sshbuf_len(b), sig_alg, 0), 0);
ASSERT_INT_EQ(sshbuf_put_string(b, sigblob, siglen), 0); /* signature */
free(sigblob);
sshbuf_free(ca_buf);
sshbuf_free(exts);
sshbuf_free(critopts);
sshbuf_free(principals);
sshbuf_free(pk);
}
static void
sig_fuzz(struct sshkey *k, const char *sig_alg)
{
struct fuzz *fuzz;
u_char *sig, c[] = "some junk to be signed";
size_t l;
u_int fuzzers = FUZZ_1_BIT_FLIP | FUZZ_1_BYTE_FLIP | FUZZ_2_BYTE_FLIP |
FUZZ_TRUNCATE_START | FUZZ_TRUNCATE_END;
if (test_is_fast())
fuzzers &= ~FUZZ_2_BYTE_FLIP;
if (test_is_slow())
fuzzers |= FUZZ_2_BIT_FLIP;
ASSERT_INT_EQ(sshkey_sign(k, &sig, &l, c, sizeof(c), sig_alg, 0), 0);
ASSERT_SIZE_T_GT(l, 0);
fuzz = fuzz_begin(fuzzers, sig, l);
ASSERT_INT_EQ(sshkey_verify(k, sig, l, c, sizeof(c), NULL, 0), 0);
free(sig);
TEST_ONERROR(onerror, fuzz);
for(; !fuzz_done(fuzz); fuzz_next(fuzz)) {
/* Ensure 1-bit difference at least */
if (fuzz_matches_original(fuzz))
continue;
ASSERT_INT_NE(sshkey_verify(k, fuzz_ptr(fuzz), fuzz_len(fuzz),
c, sizeof(c), NULL, 0), 0);
}
fuzz_cleanup(fuzz);
}
static void
build_cert(struct sshbuf *b, const struct sshkey *k, const char *type,
const struct sshkey *sign_key, const struct sshkey *ca_key)
{
struct sshbuf *ca_buf, *pk, *principals, *critopts, *exts;
u_char *sigblob;
size_t siglen;
ca_buf = sshbuf_new();
ASSERT_INT_EQ(sshkey_to_blob_buf(ca_key, ca_buf), 0);
/*
* Get the public key serialisation by rendering the key and skipping
* the type string. This is a bit of a hack :/
*/
pk = sshbuf_new();
ASSERT_INT_EQ(sshkey_plain_to_blob_buf(k, pk), 0);
ASSERT_INT_EQ(sshbuf_skip_string(pk), 0);
principals = sshbuf_new();
ASSERT_INT_EQ(sshbuf_put_cstring(principals, "gsamsa"), 0);
ASSERT_INT_EQ(sshbuf_put_cstring(principals, "gregor"), 0);
critopts = sshbuf_new();
/* XXX fill this in */
exts = sshbuf_new();
/* XXX fill this in */
ASSERT_INT_EQ(sshbuf_put_cstring(b, type), 0);
ASSERT_INT_EQ(sshbuf_put_cstring(b, "noncenoncenonce!"), 0); /* nonce */
ASSERT_INT_EQ(sshbuf_putb(b, pk), 0); /* public key serialisation */
ASSERT_INT_EQ(sshbuf_put_u64(b, 1234), 0); /* serial */
ASSERT_INT_EQ(sshbuf_put_u32(b, SSH2_CERT_TYPE_USER), 0); /* type */
ASSERT_INT_EQ(sshbuf_put_cstring(b, "gregor"), 0); /* key ID */
ASSERT_INT_EQ(sshbuf_put_stringb(b, principals), 0); /* principals */
ASSERT_INT_EQ(sshbuf_put_u64(b, 0), 0); /* start */
ASSERT_INT_EQ(sshbuf_put_u64(b, 0xffffffffffffffffULL), 0); /* end */
ASSERT_INT_EQ(sshbuf_put_stringb(b, critopts), 0); /* options */
ASSERT_INT_EQ(sshbuf_put_stringb(b, exts), 0); /* extensions */
ASSERT_INT_EQ(sshbuf_put_string(b, NULL, 0), 0); /* reserved */
ASSERT_INT_EQ(sshbuf_put_stringb(b, ca_buf), 0); /* signature key */
ASSERT_INT_EQ(sshkey_sign(sign_key, &sigblob, &siglen,
sshbuf_ptr(b), sshbuf_len(b), 0), 0);
ASSERT_INT_EQ(sshbuf_put_string(b, sigblob, siglen), 0); /* signature */
free(sigblob);
sshbuf_free(ca_buf);
sshbuf_free(exts);
sshbuf_free(critopts);
sshbuf_free(principals);
sshbuf_free(pk);
}
static void
signature_test(struct sshkey *k, struct sshkey *bad, const u_char *d, size_t l)
{
size_t len;
u_char *sig;
ASSERT_INT_EQ(sshkey_sign(k, &sig, &len, d, l, 0), 0);
ASSERT_SIZE_T_GT(len, 8);
ASSERT_PTR_NE(sig, NULL);
ASSERT_INT_EQ(sshkey_verify(k, sig, len, d, l, 0), 0);
ASSERT_INT_NE(sshkey_verify(bad, sig, len, d, l, 0), 0);
/* Fuzz test is more comprehensive, this is just a smoke test */
sig[len - 5] ^= 0x10;
ASSERT_INT_NE(sshkey_verify(k, sig, len, d, l, 0), 0);
free(sig);
}
static void
sig_fuzz(struct sshkey *k)
{
struct fuzz *fuzz;
u_char *sig, c[] = "some junk to be signed";
size_t l;
ASSERT_INT_EQ(sshkey_sign(k, &sig, &l, c, sizeof(c), 0), 0);
ASSERT_SIZE_T_GT(l, 0);
fuzz = fuzz_begin(FUZZ_1_BIT_FLIP | /* too slow FUZZ_2_BIT_FLIP | */
FUZZ_1_BYTE_FLIP | FUZZ_2_BYTE_FLIP |
FUZZ_TRUNCATE_START | FUZZ_TRUNCATE_END, sig, l);
ASSERT_INT_EQ(sshkey_verify(k, sig, l, c, sizeof(c), 0), 0);
free(sig);
TEST_ONERROR(onerror, fuzz);
for(; !fuzz_done(fuzz); fuzz_next(fuzz)) {
sshkey_verify(k, fuzz_ptr(fuzz), fuzz_len(fuzz),
c, sizeof(c), 0);
}
fuzz_cleanup(fuzz);
}
int
main(int argc, char **argv)
{
struct sshbuf *b;
Options options;
#define NUM_KEYTYPES 4
struct sshkey *keys[NUM_KEYTYPES], *key = NULL;
struct passwd *pw;
int r, key_fd[NUM_KEYTYPES], i, found, version = 2, fd;
u_char *signature, *data, rver;
char *host, *fp;
size_t slen, dlen;
#ifdef WITH_OPENSSL
u_int32_t rnd[256];
#endif
if (pledge("stdio rpath getpw dns id", NULL) != 0)
fatal("%s: pledge: %s", __progname, strerror(errno));
/* Ensure that stdin and stdout are connected */
if ((fd = open(_PATH_DEVNULL, O_RDWR)) < 2)
exit(1);
/* Leave /dev/null fd iff it is attached to stderr */
if (fd > 2)
close(fd);
i = 0;
/* XXX This really needs to read sshd_config for the paths */
key_fd[i++] = open(_PATH_HOST_DSA_KEY_FILE, O_RDONLY);
key_fd[i++] = open(_PATH_HOST_ECDSA_KEY_FILE, O_RDONLY);
key_fd[i++] = open(_PATH_HOST_ED25519_KEY_FILE, O_RDONLY);
key_fd[i++] = open(_PATH_HOST_RSA_KEY_FILE, O_RDONLY);
original_real_uid = getuid(); /* XXX readconf.c needs this */
if ((pw = getpwuid(original_real_uid)) == NULL)
fatal("getpwuid failed");
pw = pwcopy(pw);
permanently_set_uid(pw);
seed_rng();
#ifdef DEBUG_SSH_KEYSIGN
log_init("ssh-keysign", SYSLOG_LEVEL_DEBUG3, SYSLOG_FACILITY_AUTH, 0);
#endif
/* verify that ssh-keysign is enabled by the admin */
initialize_options(&options);
(void)read_config_file(_PATH_HOST_CONFIG_FILE, pw, "", "", &options, 0);
fill_default_options(&options);
if (options.enable_ssh_keysign != 1)
fatal("ssh-keysign not enabled in %s",
_PATH_HOST_CONFIG_FILE);
for (i = found = 0; i < NUM_KEYTYPES; i++) {
if (key_fd[i] != -1)
found = 1;
}
if (found == 0)
fatal("could not open any host key");
#ifdef WITH_OPENSSL
OpenSSL_add_all_algorithms();
arc4random_buf(rnd, sizeof(rnd));
RAND_seed(rnd, sizeof(rnd));
#endif
found = 0;
for (i = 0; i < NUM_KEYTYPES; i++) {
keys[i] = NULL;
if (key_fd[i] == -1)
continue;
r = sshkey_load_private_type_fd(key_fd[i], KEY_UNSPEC,
NULL, &key, NULL);
close(key_fd[i]);
if (r != 0)
debug("parse key %d: %s", i, ssh_err(r));
else if (key != NULL) {
keys[i] = key;
found = 1;
}
}
if (!found)
fatal("no hostkey found");
if (pledge("stdio dns", NULL) != 0)
fatal("%s: pledge: %s", __progname, strerror(errno));
if ((b = sshbuf_new()) == NULL)
fatal("%s: sshbuf_new failed", __progname);
if (ssh_msg_recv(STDIN_FILENO, b) < 0)
fatal("ssh_msg_recv failed");
if ((r = sshbuf_get_u8(b, &rver)) != 0)
fatal("%s: buffer error: %s", __progname, ssh_err(r));
if (rver != version)
fatal("bad version: received %d, expected %d", rver, version);
if ((r = sshbuf_get_u32(b, (u_int *)&fd)) != 0)
fatal("%s: buffer error: %s", __progname, ssh_err(r));
if (fd < 0 || fd == STDIN_FILENO || fd == STDOUT_FILENO)
fatal("bad fd");
if ((host = get_local_name(fd)) == NULL)
fatal("cannot get local name for fd");
if ((r = sshbuf_get_string(b, &data, &dlen)) != 0)
fatal("%s: buffer error: %s", __progname, ssh_err(r));
if (valid_request(pw, host, &key, data, dlen) < 0)
fatal("not a valid request");
free(host);
found = 0;
for (i = 0; i < NUM_KEYTYPES; i++) {
if (keys[i] != NULL &&
sshkey_equal_public(key, keys[i])) {
found = 1;
break;
}
}
if (!found) {
if ((fp = sshkey_fingerprint(key, options.fingerprint_hash,
SSH_FP_DEFAULT)) == NULL)
fatal("%s: sshkey_fingerprint failed", __progname);
fatal("no matching hostkey found for key %s %s",
sshkey_type(key), fp ? fp : "");
}
if ((r = sshkey_sign(keys[i], &signature, &slen, data, dlen, NULL, 0))
!= 0)
fatal("sshkey_sign failed: %s", ssh_err(r));
free(data);
/* send reply */
sshbuf_reset(b);
if ((r = sshbuf_put_string(b, signature, slen)) != 0)
fatal("%s: buffer error: %s", __progname, ssh_err(r));
if (ssh_msg_send(STDOUT_FILENO, version, b) == -1)
fatal("ssh_msg_send failed");
return (0);
}
int
main(int argc, char **argv)
{
struct sshbuf *b;
Options options;
#define NUM_KEYTYPES 3
struct sshkey *keys[NUM_KEYTYPES], *key = NULL;
struct passwd *pw;
int r, key_fd[NUM_KEYTYPES], i, found, version = 2, fd;
u_char *signature, *data, rver;
char *host;
size_t slen, dlen;
u_int32_t rnd[256];
/* Ensure that stdin and stdout are connected */
if ((fd = open(_PATH_DEVNULL, O_RDWR)) < 2)
exit(1);
/* Leave /dev/null fd iff it is attached to stderr */
if (fd > 2)
close(fd);
i = 0;
key_fd[i++] = open(_PATH_HOST_DSA_KEY_FILE, O_RDONLY);
key_fd[i++] = open(_PATH_HOST_ECDSA_KEY_FILE, O_RDONLY);
key_fd[i++] = open(_PATH_HOST_RSA_KEY_FILE, O_RDONLY);
original_real_uid = getuid(); /* XXX readconf.c needs this */
if ((pw = getpwuid(original_real_uid)) == NULL)
fatal("getpwuid failed");
pw = pwcopy(pw);
permanently_set_uid(pw);
#ifdef DEBUG_SSH_KEYSIGN
log_init("ssh-keysign", SYSLOG_LEVEL_DEBUG3, SYSLOG_FACILITY_AUTH, 0);
#endif
/* verify that ssh-keysign is enabled by the admin */
initialize_options(&options);
(void)read_config_file(_PATH_HOST_CONFIG_FILE, "", &options, 0);
fill_default_options(&options);
if (options.enable_ssh_keysign != 1)
fatal("ssh-keysign not enabled in %s",
_PATH_HOST_CONFIG_FILE);
for (i = found = 0; i < NUM_KEYTYPES; i++) {
if (key_fd[i] != -1)
found = 1;
}
if (found == 0)
fatal("could not open any host key");
OpenSSL_add_all_algorithms();
for (i = 0; i < 256; i++)
rnd[i] = arc4random();
RAND_seed(rnd, sizeof(rnd));
found = 0;
for (i = 0; i < NUM_KEYTYPES; i++) {
keys[i] = NULL;
if (key_fd[i] == -1)
continue;
r = sshkey_load_private_pem(key_fd[i], KEY_UNSPEC,
NULL, &(keys[i]), NULL);
if (r != 0)
error("Load private: %s", ssh_err(r));
close(key_fd[i]);
if (keys[i] != NULL)
found = 1;
}
if (!found)
fatal("no hostkey found");
if ((b = sshbuf_new()) == NULL)
fatal("%s: sshbuf_new failed", __func__);
if (ssh_msg_recv(STDIN_FILENO, b) < 0)
fatal("ssh_msg_recv failed");
if ((r = sshbuf_get_u8(b, &rver)) != 0)
fatal("%s: buffer error: %s", __func__, ssh_err(r));
if (rver != version)
fatal("bad version: received %d, expected %d", rver, version);
if ((r = sshbuf_get_u32(b, &fd)) != 0)
fatal("%s: buffer error: %s", __func__, ssh_err(r));
if ((fd == STDIN_FILENO) || (fd == STDOUT_FILENO))
fatal("bad fd");
if ((host = get_local_name(fd)) == NULL)
fatal("cannot get local name for fd");
if ((r = sshbuf_get_string(b, &data, &dlen)) != 0)
fatal("%s: buffer error: %s", __func__, ssh_err(r));
if (valid_request(pw, host, &key, data, dlen) < 0)
fatal("not a valid request");
xfree(host);
found = 0;
for (i = 0; i < NUM_KEYTYPES; i++) {
if (keys[i] != NULL &&
sshkey_equal_public(key, keys[i])) {
found = 1;
break;
}
}
if (!found)
fatal("no matching hostkey found");
if ((r = sshkey_sign(keys[i], &signature, &slen, data, dlen, 0)) != 0)
fatal("sshkey_sign failed: %s", ssh_err(r));
xfree(data);
/* send reply */
sshbuf_reset(b);
if ((r = sshbuf_put_string(b, signature, slen)) != 0)
fatal("%s: buffer error: %s", __func__, ssh_err(r));
if (ssh_msg_send(STDOUT_FILENO, version, b) == -1)
fatal("ssh_msg_send failed");
return (0);
}
int
mm_answer_sign(int sock, struct sshbuf *m)
{
struct ssh *ssh = active_state; /* XXX */
extern int auth_sock; /* XXX move to state struct? */
struct sshkey *key;
u_char *p;
u_char *signature;
size_t datlen, siglen;
u_int keyid;
int r;
debug3("%s", __func__);
if ((r = sshbuf_get_u32(m, &keyid)) != 0 ||
(r = sshbuf_get_string(m, &p, &datlen)) != 0)
fatal("%s: buffer error: %s", __func__, ssh_err(r));
/*
* Supported KEX types use SHA1 (20 bytes), SHA256 (32 bytes),
* SHA384 (48 bytes) and SHA512 (64 bytes).
*/
if (datlen != 20 && datlen != 32 && datlen != 48 && datlen != 64)
fatal("%s: data length incorrect: %zu", __func__, datlen);
/* save session id, it will be passed on the first call */
if (session_id2_len == 0) {
session_id2_len = datlen;
session_id2 = xmalloc(session_id2_len);
memcpy(session_id2, p, session_id2_len);
}
if ((key = get_hostkey_by_index(keyid, ssh)) != NULL) {
if ((r = sshkey_sign(key, &signature, &siglen, p, datlen,
ssh->compat)) != 0)
fatal("%s: sshkey_sign failed: %s",
__func__, ssh_err(r));
} else if ((key = get_hostkey_public_by_index(keyid, ssh)) != NULL &&
auth_sock > 0) {
if ((r = ssh_agent_sign(auth_sock, key, &signature, &siglen,
p, datlen, ssh->compat)) != 0) {
fatal("%s: ssh_agent_sign failed: %s",
__func__, ssh_err(r));
}
} else
fatal("%s: no hostkey from index %d", __func__, keyid);
debug3("%s: signature %p(%zu)", __func__, signature, siglen);
sshbuf_reset(m);
if ((r = sshbuf_put_string(m, signature, siglen)) != 0)
fatal("%s: buffer error: %s", __func__, ssh_err(r));
free(p);
free(signature);
mm_request_send(sock, MONITOR_ANS_SIGN, m);
/* Turn on permissions for getpwnam */
monitor_permit(mon_dispatch, MONITOR_REQ_PWNAM, 1);
return (0);
}
int
mm_answer_sign(int sock, Buffer *m)
{
struct ssh *ssh = active_state; /* XXX */
extern int auth_sock; /* XXX move to state struct? */
struct sshkey *key;
struct sshbuf *sigbuf = NULL;
u_char *p = NULL, *signature = NULL;
char *alg = NULL;
size_t datlen, siglen, alglen;
int r, is_proof = 0;
u_int keyid;
const char proof_req[] = "*****@*****.**";
debug3("%s", __func__);
if ((r = sshbuf_get_u32(m, &keyid)) != 0 ||
(r = sshbuf_get_string(m, &p, &datlen)) != 0 ||
(r = sshbuf_get_cstring(m, &alg, &alglen)) != 0)
fatal("%s: buffer error: %s", __func__, ssh_err(r));
if (keyid > INT_MAX)
fatal("%s: invalid key ID", __func__);
/*
* Supported KEX types use SHA1 (20 bytes), SHA256 (32 bytes),
* SHA384 (48 bytes) and SHA512 (64 bytes).
*
* Otherwise, verify the signature request is for a hostkey
* proof.
*
* XXX perform similar check for KEX signature requests too?
* it's not trivial, since what is signed is the hash, rather
* than the full kex structure...
*/
if (datlen != 20 && datlen != 32 && datlen != 48 && datlen != 64) {
/*
* Construct expected hostkey proof and compare it to what
* the client sent us.
*/
if (session_id2_len == 0) /* hostkeys is never first */
fatal("%s: bad data length: %zu", __func__, datlen);
if ((key = get_hostkey_public_by_index(keyid, ssh)) == NULL)
fatal("%s: no hostkey for index %d", __func__, keyid);
if ((sigbuf = sshbuf_new()) == NULL)
fatal("%s: sshbuf_new", __func__);
if ((r = sshbuf_put_cstring(sigbuf, proof_req)) != 0 ||
(r = sshbuf_put_string(sigbuf, session_id2,
session_id2_len)) != 0 ||
(r = sshkey_puts(key, sigbuf)) != 0)
fatal("%s: couldn't prepare private key "
"proof buffer: %s", __func__, ssh_err(r));
if (datlen != sshbuf_len(sigbuf) ||
memcmp(p, sshbuf_ptr(sigbuf), sshbuf_len(sigbuf)) != 0)
fatal("%s: bad data length: %zu, hostkey proof len %zu",
__func__, datlen, sshbuf_len(sigbuf));
sshbuf_free(sigbuf);
is_proof = 1;
}
/* save session id, it will be passed on the first call */
if (session_id2_len == 0) {
session_id2_len = datlen;
session_id2 = xmalloc(session_id2_len);
memcpy(session_id2, p, session_id2_len);
}
if ((key = get_hostkey_by_index(keyid)) != NULL) {
if ((r = sshkey_sign(key, &signature, &siglen, p, datlen, alg,
datafellows)) != 0)
fatal("%s: sshkey_sign failed: %s",
__func__, ssh_err(r));
} else if ((key = get_hostkey_public_by_index(keyid, ssh)) != NULL &&
auth_sock > 0) {
if ((r = ssh_agent_sign(auth_sock, key, &signature, &siglen,
p, datlen, alg, datafellows)) != 0) {
fatal("%s: ssh_agent_sign failed: %s",
__func__, ssh_err(r));
}
} else
fatal("%s: no hostkey from index %d", __func__, keyid);
debug3("%s: %s signature %p(%zu)", __func__,
is_proof ? "KEX" : "hostkey proof", signature, siglen);
sshbuf_reset(m);
if ((r = sshbuf_put_string(m, signature, siglen)) != 0)
fatal("%s: buffer error: %s", __func__, ssh_err(r));
free(alg);
free(p);
free(signature);
mm_request_send(sock, MONITOR_ANS_SIGN, m);
/* Turn on permissions for getpwnam */
monitor_permit(mon_dispatch, MONITOR_REQ_PWNAM, 1);
return (0);
}
static int
input_kex_dh_gex_init(int type, u_int32_t seq, struct ssh *ssh)
{
Kex *kex = ssh->kex;
BIGNUM *shared_secret = NULL, *dh_client_pub = NULL;
struct sshkey *server_host_public, *server_host_private;
u_char *kbuf = NULL, *signature = NULL, *server_host_key_blob = NULL;
u_char *hash;
u_int sbloblen, slen;
size_t klen = 0, hashlen;
int kout, r;
if (kex->load_host_public_key == NULL ||
kex->load_host_private_key == NULL) {
r = SSH_ERR_INVALID_ARGUMENT;
goto out;
}
if ((server_host_public = kex->load_host_public_key(kex->hostkey_type,
ssh)) == NULL ||
(server_host_private = kex->load_host_private_key(kex->hostkey_type,
ssh)) == NULL) {
r = SSH_ERR_NO_HOSTKEY_LOADED;
goto out;
}
/* key, cert */
if ((dh_client_pub = BN_new()) == NULL) {
r = SSH_ERR_ALLOC_FAIL;
goto out;
}
if ((r = sshpkt_get_bignum2(ssh, dh_client_pub)) != 0 ||
(r = sshpkt_get_end(ssh)) != 0)
goto out;
#ifdef DEBUG_KEXDH
fprintf(stderr, "dh_client_pub= ");
BN_print_fp(stderr, dh_client_pub);
fprintf(stderr, "\n");
debug("bits %d", BN_num_bits(dh_client_pub));
#endif
#ifdef DEBUG_KEXDH
DHparams_print_fp(stderr, kex->dh);
fprintf(stderr, "pub= ");
BN_print_fp(stderr, kex->dh->pub_key);
fprintf(stderr, "\n");
#endif
if (!dh_pub_is_valid(kex->dh, dh_client_pub)) {
sshpkt_disconnect(ssh, "bad client public DH value");
r = SSH_ERR_MESSAGE_INCOMPLETE;
goto out;
}
klen = DH_size(kex->dh);
if ((kbuf = malloc(klen)) == NULL ||
(shared_secret = BN_new()) == NULL) {
r = SSH_ERR_ALLOC_FAIL;
goto out;
}
if ((kout = DH_compute_key(kbuf, dh_client_pub, kex->dh)) < 0 ||
BN_bin2bn(kbuf, kout, shared_secret) == NULL) {
r = SSH_ERR_LIBCRYPTO_ERROR;
goto out;
}
#ifdef DEBUG_KEXDH
dump_digest("shared secret", kbuf, kout);
#endif
if ((r = sshkey_to_blob(server_host_public, &server_host_key_blob,
&sbloblen)) != 0)
goto out;
/* calc H */
if ((r = kexgex_hash(
kex->evp_md,
kex->client_version_string,
kex->server_version_string,
sshbuf_ptr(kex->peer), sshbuf_len(kex->peer),
sshbuf_ptr(kex->my), sshbuf_len(kex->my),
server_host_key_blob, sbloblen,
kex->min, kex->nbits, kex->max,
kex->dh->p, kex->dh->g,
dh_client_pub,
kex->dh->pub_key,
shared_secret,
&hash, &hashlen)) != 0)
goto out;
/* save session id := H */
if (kex->session_id == NULL) {
kex->session_id_len = hashlen;
kex->session_id = malloc(kex->session_id_len);
if (kex->session_id == NULL) {
r = SSH_ERR_ALLOC_FAIL;
goto out;
}
memcpy(kex->session_id, hash, kex->session_id_len);
}
/* sign H */
if ((r = PRIVSEP(sshkey_sign(server_host_private, &signature, &slen,
hash, hashlen, ssh->compat))) < 0)
goto out;
/* destroy_sensitive_data(); */
/* send server hostkey, DH pubkey 'f' and singed H */
if ((r = sshpkt_start(ssh, SSH2_MSG_KEX_DH_GEX_REPLY)) != 0 ||
(r = sshpkt_put_string(ssh, server_host_key_blob, sbloblen)) != 0 ||
(r = sshpkt_put_bignum2(ssh, kex->dh->pub_key)) != 0 || /* f */
(r = sshpkt_put_string(ssh, signature, slen)) != 0 ||
(r = sshpkt_send(ssh)) != 0)
goto out;
if ((r = kex_derive_keys(ssh, hash, hashlen, shared_secret)) == 0)
r = kex_send_newkeys(ssh);
out:
DH_free(kex->dh);
kex->dh = NULL;
if (dh_client_pub)
BN_clear_free(dh_client_pub);
if (kbuf) {
bzero(kbuf, klen);
free(kbuf);
}
if (shared_secret)
BN_clear_free(shared_secret);
if (server_host_key_blob)
free(server_host_key_blob);
if (signature)
free(signature);
return r;
}
