/* Convert success/failure response from agent to a err.h status */
static int
decode_reply(u_char type)
{
if (agent_failed(type))
return SSH_ERR_AGENT_FAILURE;
else if (type == SSH_AGENT_SUCCESS)
return 0;
else
return SSH_ERR_INVALID_FORMAT;
}
/* ask agent to sign data, returns err.h code on error, 0 on success */
int
ssh_agent_sign(int sock, struct sshkey *key,
u_char **sigp, size_t *lenp,
const u_char *data, size_t datalen, u_int compat)
{
struct sshbuf *msg;
u_char *blob = NULL, type;
size_t blen = 0, len = 0;
u_int flags = 0;
int r = SSH_ERR_INTERNAL_ERROR;
if (sigp != NULL)
*sigp = NULL;
if (lenp != NULL)
*lenp = 0;
if (datalen > SSH_KEY_MAX_SIGN_DATA_SIZE)
return SSH_ERR_INVALID_ARGUMENT;
if (compat & SSH_BUG_SIGBLOB)
flags |= SSH_AGENT_OLD_SIGNATURE;
if ((msg = sshbuf_new()) == NULL)
return SSH_ERR_ALLOC_FAIL;
if ((r = sshkey_to_blob(key, &blob, &blen)) != 0)
goto out;
if ((r = sshbuf_put_u8(msg, SSH2_AGENTC_SIGN_REQUEST)) != 0 ||
(r = sshbuf_put_string(msg, blob, blen)) != 0 ||
(r = sshbuf_put_string(msg, data, datalen)) != 0 ||
(r = sshbuf_put_u32(msg, flags)) != 0)
goto out;
if ((r = ssh_request_reply(sock, msg, msg) != 0))
goto out;
if ((r = sshbuf_get_u8(msg, &type)) != 0)
goto out;
if (agent_failed(type)) {
r = SSH_ERR_AGENT_FAILURE;
goto out;
} else if (type != SSH2_AGENT_SIGN_RESPONSE) {
r = SSH_ERR_INVALID_FORMAT;
goto out;
}
if ((r = sshbuf_get_string(msg, sigp, &len)) != 0)
goto out;
*lenp = len;
r = 0;
out:
if (blob != NULL) {
explicit_bzero(blob, blen);
free(blob);
}
sshbuf_free(msg);
return r;
}
int
ssh_decrypt_challenge(AuthenticationConnection *auth,
Key* key, BIGNUM *challenge,
u_char session_id[16],
u_int response_type,
u_char response[16])
{
Buffer buffer;
int success = 0;
int i;
int type;
if (key->type != KEY_RSA1)
return 0;
if (response_type == 0) {
pamsshagentauth_logit("Compatibility with ssh protocol version 1.0 no longer supported.");
return 0;
}
pamsshagentauth_buffer_init(&buffer);
pamsshagentauth_buffer_put_char(&buffer, SSH_AGENTC_RSA_CHALLENGE);
pamsshagentauth_buffer_put_int(&buffer, BN_num_bits(key->rsa->n));
pamsshagentauth_buffer_put_bignum(&buffer, key->rsa->e);
pamsshagentauth_buffer_put_bignum(&buffer, key->rsa->n);
pamsshagentauth_buffer_put_bignum(&buffer, challenge);
pamsshagentauth_buffer_append(&buffer, session_id, 16);
pamsshagentauth_buffer_put_int(&buffer, response_type);
if (ssh_request_reply(auth, &buffer, &buffer) == 0) {
pamsshagentauth_buffer_free(&buffer);
return 0;
}
type = pamsshagentauth_buffer_get_char(&buffer);
if (agent_failed(type)) {
pamsshagentauth_logit("Agent admitted failure to authenticate using the key.");
} else if (type != SSH_AGENT_RSA_RESPONSE) {
pamsshagentauth_fatal("Bad authentication response: %d", type);
} else {
success = 1;
/*
* Get the response from the packet. This will abort with a
* fatal error if the packet is corrupt.
*/
for (i = 0; i < 16; i++)
response[i] = (u_char)pamsshagentauth_buffer_get_char(&buffer);
}
pamsshagentauth_buffer_free(&buffer);
return success;
}
int
ssh_get_num_identities(AuthenticationConnection *auth, int version)
{
int type, code1 = 0, code2 = 0;
Buffer request;
switch (version) {
case 1:
code1 = SSH_AGENTC_REQUEST_RSA_IDENTITIES;
code2 = SSH_AGENT_RSA_IDENTITIES_ANSWER;
break;
case 2:
code1 = SSH2_AGENTC_REQUEST_IDENTITIES;
code2 = SSH2_AGENT_IDENTITIES_ANSWER;
break;
default:
return 0;
}
/*
* Send a message to the agent requesting for a list of the
* identities it can represent.
*/
pamsshagentauth_buffer_init(&request);
pamsshagentauth_buffer_put_char(&request, code1);
pamsshagentauth_buffer_clear(&auth->identities);
if (ssh_request_reply(auth, &request, &auth->identities) == 0) {
pamsshagentauth_buffer_free(&request);
return 0;
}
pamsshagentauth_buffer_free(&request);
/* Get message type, and verify that we got a proper answer. */
type = pamsshagentauth_buffer_get_char(&auth->identities);
if (agent_failed(type)) {
return 0;
} else if (type != code2) {
pamsshagentauth_fatal("Bad authentication reply message type: %d", type);
}
/* Get the number of entries in the response and check it for sanity. */
auth->howmany = pamsshagentauth_buffer_get_int(&auth->identities);
if ((u_int)auth->howmany > 1024)
pamsshagentauth_fatal("Too many identities in authentication reply: %d",
auth->howmany);
return auth->howmany;
}
/* ask agent to sign data, returns -1 on error, 0 on success */
int
ssh_agent_sign(AuthenticationConnection *auth,
Key *key,
u_char **sigp, u_int *lenp,
u_char *data, u_int datalen)
{
extern int datafellows;
Buffer msg;
u_char *blob;
u_int blen;
int type, flags = 0;
int ret = -1;
if (pamsshagentauth_key_to_blob(key, &blob, &blen) == 0)
return -1;
if (datafellows & SSH_BUG_SIGBLOB)
flags = SSH_AGENT_OLD_SIGNATURE;
pamsshagentauth_buffer_init(&msg);
pamsshagentauth_buffer_put_char(&msg, SSH2_AGENTC_SIGN_REQUEST);
pamsshagentauth_buffer_put_string(&msg, blob, blen);
pamsshagentauth_buffer_put_string(&msg, data, datalen);
pamsshagentauth_buffer_put_int(&msg, flags);
pamsshagentauth_xfree(blob);
if (ssh_request_reply(auth, &msg, &msg) == 0) {
pamsshagentauth_buffer_free(&msg);
return -1;
}
type = pamsshagentauth_buffer_get_char(&msg);
if (agent_failed(type)) {
pamsshagentauth_logit("Agent admitted failure to sign using the key.");
} else if (type != SSH2_AGENT_SIGN_RESPONSE) {
pamsshagentauth_fatal("Bad authentication response: %d", type);
} else {
ret = 0;
*sigp = pamsshagentauth_buffer_get_string(&msg, lenp);
}
pamsshagentauth_buffer_free(&msg);
return ret;
}
int
ssh_decrypt_challenge(int sock, struct sshkey* key, BIGNUM *challenge,
u_char session_id[16], u_char response[16])
{
struct sshbuf *msg;
int r;
u_char type;
if (key->type != KEY_RSA1)
return SSH_ERR_INVALID_ARGUMENT;
if ((msg = sshbuf_new()) == NULL)
return SSH_ERR_ALLOC_FAIL;
if ((r = sshbuf_put_u8(msg, SSH_AGENTC_RSA_CHALLENGE)) != 0 ||
(r = sshbuf_put_u32(msg, BN_num_bits(key->rsa->n))) != 0 ||
(r = sshbuf_put_bignum1(msg, key->rsa->e)) != 0 ||
(r = sshbuf_put_bignum1(msg, key->rsa->n)) != 0 ||
(r = sshbuf_put_bignum1(msg, challenge)) != 0 ||
(r = sshbuf_put(msg, session_id, 16)) != 0 ||
(r = sshbuf_put_u32(msg, 1)) != 0) /* Response type for proto 1.1 */
goto out;
if ((r = ssh_request_reply(sock, msg, msg)) != 0)
goto out;
if ((r = sshbuf_get_u8(msg, &type)) != 0)
goto out;
if (agent_failed(type)) {
r = SSH_ERR_AGENT_FAILURE;
goto out;
} else if (type != SSH_AGENT_RSA_RESPONSE) {
r = SSH_ERR_INVALID_FORMAT;
goto out;
}
if ((r = sshbuf_get(msg, response, 16)) != 0)
goto out;
r = 0;
out:
sshbuf_free(msg);
return r;
}
/*
* Fetch list of identities held by the agent.
*/
int
ssh_fetch_identitylist(int sock, int version, struct ssh_identitylist **idlp)
{
u_char type, code1 = 0, code2 = 0;
u_int32_t num, i;
struct sshbuf *msg;
struct ssh_identitylist *idl = NULL;
int r;
/* Determine request and expected response types */
switch (version) {
case 1:
code1 = SSH_AGENTC_REQUEST_RSA_IDENTITIES;
code2 = SSH_AGENT_RSA_IDENTITIES_ANSWER;
break;
case 2:
code1 = SSH2_AGENTC_REQUEST_IDENTITIES;
code2 = SSH2_AGENT_IDENTITIES_ANSWER;
break;
default:
return SSH_ERR_INVALID_ARGUMENT;
}
/*
* Send a message to the agent requesting for a list of the
* identities it can represent.
*/
if ((msg = sshbuf_new()) == NULL)
return SSH_ERR_ALLOC_FAIL;
if ((r = sshbuf_put_u8(msg, code1)) != 0)
goto out;
if ((r = ssh_request_reply(sock, msg, msg)) != 0)
goto out;
/* Get message type, and verify that we got a proper answer. */
if ((r = sshbuf_get_u8(msg, &type)) != 0)
goto out;
if (agent_failed(type)) {
r = SSH_ERR_AGENT_FAILURE;
goto out;
} else if (type != code2) {
r = SSH_ERR_INVALID_FORMAT;
goto out;
}
/* Get the number of entries in the response and check it for sanity. */
if ((r = sshbuf_get_u32(msg, &num)) != 0)
goto out;
if (num > MAX_AGENT_IDENTITIES) {
r = SSH_ERR_INVALID_FORMAT;
goto out;
}
if (num == 0) {
r = SSH_ERR_AGENT_NO_IDENTITIES;
goto out;
}
/* Deserialise the response into a list of keys/comments */
if ((idl = calloc(1, sizeof(*idl))) == NULL ||
(idl->keys = calloc(num, sizeof(*idl->keys))) == NULL ||
(idl->comments = calloc(num, sizeof(*idl->comments))) == NULL) {
r = SSH_ERR_ALLOC_FAIL;
goto out;
}
for (i = 0; i < num;) {
switch (version) {
case 1:
#ifdef WITH_SSH1
if ((r = deserialise_identity1(msg,
&(idl->keys[i]), &(idl->comments[i]))) != 0)
goto out;
#endif
break;
case 2:
if ((r = deserialise_identity2(msg,
&(idl->keys[i]), &(idl->comments[i]))) != 0) {
if (r == SSH_ERR_KEY_TYPE_UNKNOWN) {
/* Gracefully skip unknown key types */
num--;
continue;
} else
goto out;
}
break;
}
i++;
}
idl->nkeys = num;
*idlp = idl;
idl = NULL;
r = 0;
out:
sshbuf_free(msg);
if (idl != NULL)
ssh_free_identitylist(idl);
return r;
}
ssh_string ssh_agent_sign_data(ssh_session session,
const ssh_key pubkey,
struct ssh_buffer_struct *data)
{
ssh_buffer request;
ssh_buffer reply;
ssh_string key_blob;
ssh_string sig_blob;
int type = SSH2_AGENT_FAILURE;
int flags = 0;
uint32_t dlen;
int rc;
request = ssh_buffer_new();
if (request == NULL) {
return NULL;
}
/* create request */
if (buffer_add_u8(request, SSH2_AGENTC_SIGN_REQUEST) < 0) {
return NULL;
}
rc = ssh_pki_export_pubkey_blob(pubkey, &key_blob);
if (rc < 0) {
ssh_buffer_free(request);
return NULL;
}
/* adds len + blob */
rc = buffer_add_ssh_string(request, key_blob);
ssh_string_free(key_blob);
if (rc < 0) {
ssh_buffer_free(request);
return NULL;
}
/* Add data */
dlen = buffer_get_rest_len(data);
if (buffer_add_u32(request, htonl(dlen)) < 0) {
ssh_buffer_free(request);
return NULL;
}
if (buffer_add_data(request, buffer_get_rest(data), dlen) < 0) {
ssh_buffer_free(request);
return NULL;
}
if (buffer_add_u32(request, htonl(flags)) < 0) {
ssh_buffer_free(request);
return NULL;
}
reply = ssh_buffer_new();
if (reply == NULL) {
ssh_buffer_free(request);
return NULL;
}
/* send the request */
if (agent_talk(session, request, reply) < 0) {
ssh_buffer_free(request);
return NULL;
}
ssh_buffer_free(request);
/* check if reply is valid */
if (buffer_get_u8(reply, (uint8_t *) &type) != sizeof(uint8_t)) {
ssh_buffer_free(reply);
return NULL;
}
if (agent_failed(type)) {
SSH_LOG(session, SSH_LOG_WARN, "Agent reports failure in signing the key");
ssh_buffer_free(reply);
return NULL;
} else if (type != SSH2_AGENT_SIGN_RESPONSE) {
ssh_set_error(session, SSH_FATAL, "Bad authentication response: %d", type);
ssh_buffer_free(reply);
return NULL;
}
sig_blob = buffer_get_ssh_string(reply);
ssh_buffer_free(reply);
return sig_blob;
}
int ssh_agent_get_ident_count(struct ssh_session_struct *session) {
ssh_buffer request = NULL;
ssh_buffer reply = NULL;
unsigned int type = 0;
unsigned int c1 = 0, c2 = 0;
uint32_t buf = 0;
switch (session->version) {
case 1:
c1 = SSH_AGENTC_REQUEST_RSA_IDENTITIES;
c2 = SSH_AGENT_RSA_IDENTITIES_ANSWER;
break;
case 2:
c1 = SSH2_AGENTC_REQUEST_IDENTITIES;
c2 = SSH2_AGENT_IDENTITIES_ANSWER;
break;
default:
return 0;
}
/* send message to the agent requesting the list of identities */
request = ssh_buffer_new();
if (buffer_add_u8(request, c1) < 0) {
ssh_set_error(session, SSH_FATAL, "Not enough space");
return -1;
}
reply = ssh_buffer_new();
if (reply == NULL) {
ssh_set_error(session, SSH_FATAL, "Not enough space");
return -1;
}
if (agent_talk(session, request, reply) < 0) {
ssh_buffer_free(request);
return 0;
}
ssh_buffer_free(request);
/* get message type and verify the answer */
buffer_get_u8(reply, (uint8_t *) &type);
SSH_LOG(session, SSH_LOG_WARN,
"Answer type: %d, expected answer: %d",
type, c2);
if (agent_failed(type)) {
return 0;
} else if (type != c2) {
ssh_set_error(session, SSH_FATAL,
"Bad authentication reply message type: %d", type);
return -1;
}
buffer_get_u32(reply, &buf);
session->agent->count = agent_get_u32((uint8_t*)&buf);
SSH_LOG(session, SSH_LOG_DEBUG, "Agent count: %d",
session->agent->count);
if (session->agent->count > 1024) {
ssh_set_error(session, SSH_FATAL,
"Too many identities in authentication reply: %d",
session->agent->count);
ssh_buffer_free(reply);
return -1;
}
if (session->agent->ident) {
buffer_reinit(session->agent->ident);
}
session->agent->ident = reply;
return session->agent->count;
}
ssh_string agent_sign_data(struct ssh_session_struct *session,
struct ssh_buffer_struct *data,
struct ssh_public_key_struct *pubkey) {
struct ssh_string_struct *blob = NULL;
struct ssh_string_struct *sig = NULL;
struct ssh_buffer_struct *request = NULL;
struct ssh_buffer_struct *reply = NULL;
int type = SSH2_AGENT_FAILURE;
int flags = 0;
uint32_t dlen = 0;
/* create blob from the pubkey */
blob = publickey_to_string(pubkey);
request = buffer_new();
if (request == NULL) {
goto error;
}
/* create request */
if (buffer_add_u8(request, SSH2_AGENTC_SIGN_REQUEST) < 0) {
goto error;
}
/* adds len + blob */
if (buffer_add_ssh_string(request, blob) < 0) {
goto error;
}
/* Add data */
dlen = buffer_get_len(data);
if (buffer_add_u32(request, htonl(dlen)) < 0) {
goto error;
}
if (buffer_add_data(request, buffer_get(data), dlen) < 0) {
goto error;
}
if (buffer_add_u32(request, htonl(flags)) < 0) {
goto error;
}
string_free(blob);
reply = buffer_new();
if (reply == NULL) {
goto error;
}
/* send the request */
if (agent_talk(session, request, reply) < 0) {
buffer_free(request);
return NULL;
}
buffer_free(request);
/* check if reply is valid */
if (buffer_get_u8(reply, (uint8_t *) &type) != sizeof(uint8_t)) {
goto error;
}
if (agent_failed(type)) {
ssh_log(session, SSH_LOG_RARE, "Agent reports failure in signing the key");
buffer_free(reply);
return NULL;
} else if (type != SSH2_AGENT_SIGN_RESPONSE) {
ssh_set_error(session, SSH_FATAL, "Bad authentication response: %d", type);
buffer_free(reply);
return NULL;
}
sig = buffer_get_ssh_string(reply);
buffer_free(reply);
return sig;
error:
ssh_set_error(session, SSH_FATAL, "Not enough memory");
string_free(blob);
buffer_free(request);
buffer_free(reply);
return NULL;
}