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1032 lines (898 loc) · 31.1 KB
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/*
* Copyright (C) Daiki Ueno
* Copyright (C) Daniel Stenberg
* All rights reserved.
*
* Redistribution and use in source and binary forms,
* with or without modification, are permitted provided
* that the following conditions are met:
*
* Redistributions of source code must retain the above
* copyright notice, this list of conditions and the
* following disclaimer.
*
* 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.
*
* Neither the name of the copyright holder nor the names
* of any other contributors may be used to endorse or
* promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
* CONTRIBUTORS "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 COPYRIGHT OWNER OR
* CONTRIBUTORS 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.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
#include "libssh2_priv.h"
#include <errno.h>
#include <stdlib.h> /* for getenv() */
#ifdef HAVE_SYS_UN_H
#include <sys/un.h>
#else
/* Use the existence of sys/un.h as a test if Unix domain socket is
supported. winsock*.h define PF_UNIX/AF_UNIX but do not actually
support them. */
#undef PF_UNIX
#endif
#if defined(_WIN32) && !defined(LIBSSH2_WINDOWS_UWP)
#define HAVE_WIN32_AGENTS
#endif
#include "userauth.h"
#include "session.h"
#if 0
/* Requests from client to agent for protocol 1 key operations */
#define SSH_AGENTC_REQUEST_RSA_IDENTITIES 1
#define SSH_AGENTC_RSA_CHALLENGE 3
#define SSH_AGENTC_ADD_RSA_IDENTITY 7
#define SSH_AGENTC_REMOVE_RSA_IDENTITY 8
#define SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES 9
#define SSH_AGENTC_ADD_RSA_ID_CONSTRAINED 24
#endif
/* Requests from client to agent for protocol 2 key operations */
#define SSH2_AGENTC_REQUEST_IDENTITIES 11
#define SSH2_AGENTC_SIGN_REQUEST 13
#if 0
#define SSH2_AGENTC_ADD_IDENTITY 17
#define SSH2_AGENTC_REMOVE_IDENTITY 18
#define SSH2_AGENTC_REMOVE_ALL_IDENTITIES 19
#define SSH2_AGENTC_ADD_ID_CONSTRAINED 25
/* Key-type independent requests from client to agent */
#define SSH_AGENTC_ADD_SMARTCARD_KEY 20
#define SSH_AGENTC_REMOVE_SMARTCARD_KEY 21
#define SSH_AGENTC_LOCK 22
#define SSH_AGENTC_UNLOCK 23
#define SSH_AGENTC_ADD_SMARTCARD_KEY_CONSTRAINED 26
/* Generic replies from agent to client */
#define SSH_AGENT_FAILURE 5
#define SSH_AGENT_SUCCESS 6
/* Replies from agent to client for protocol 1 key operations */
#define SSH_AGENT_RSA_IDENTITIES_ANSWER 2
#define SSH_AGENT_RSA_RESPONSE 4
/* Key constraint identifiers */
#define SSH_AGENT_CONSTRAIN_LIFETIME 1
#define SSH_AGENT_CONSTRAIN_CONFIRM 2
#endif
/* Replies from agent to client for protocol 2 key operations */
#define SSH2_AGENT_IDENTITIES_ANSWER 12
#define SSH2_AGENT_SIGN_RESPONSE 14
/* Signature request methods */
#define SSH_AGENT_RSA_SHA2_256 2
#define SSH_AGENT_RSA_SHA2_512 4
/* non-blocking mode on agent connection is not yet implemented, but
for future use. */
typedef enum {
agent_NB_state_init = 0,
agent_NB_state_request_created,
agent_NB_state_request_length_sent,
agent_NB_state_request_sent,
agent_NB_state_response_length_received,
agent_NB_state_response_received
} agent_nonblocking_states;
typedef struct agent_transaction_ctx {
unsigned char *request;
size_t request_len;
unsigned char *response;
size_t response_len;
agent_nonblocking_states state;
size_t send_recv_total;
} *agent_transaction_ctx_t;
typedef int (*agent_connect_func)(LIBSSH2_AGENT *agent);
typedef int (*agent_transact_func)(LIBSSH2_AGENT *agent,
agent_transaction_ctx_t transctx);
typedef int (*agent_disconnect_func)(LIBSSH2_AGENT *agent);
struct agent_publickey {
struct list_node node;
/* this is the struct we expose externally */
struct libssh2_agent_publickey external;
};
struct agent_ops {
const agent_connect_func connect;
const agent_transact_func transact;
const agent_disconnect_func disconnect;
};
struct _LIBSSH2_AGENT
{
LIBSSH2_SESSION *session; /* the session this "belongs to" */
libssh2_socket_t fd;
struct agent_ops *ops;
struct agent_transaction_ctx transctx;
struct agent_publickey *identity;
struct list_head head; /* list of public keys */
char *identity_agent_path; /* Path to a custom identity agent socket */
#ifdef HAVE_WIN32_AGENTS
OVERLAPPED overlapped;
HANDLE pipe;
BOOL pending_io;
#endif
};
#include "agent_win.c"
#ifdef PF_UNIX
static int
agent_connect_unix(LIBSSH2_AGENT *agent)
{
const char *path;
struct sockaddr_un s_un;
path = agent->identity_agent_path;
if(!path) {
path = getenv("SSH_AUTH_SOCK");
if(!path)
return _libssh2_error(agent->session, LIBSSH2_ERROR_BAD_USE,
"no auth sock variable");
}
agent->fd = socket(PF_UNIX, SOCK_STREAM, 0);
if(agent->fd < 0)
return _libssh2_error(agent->session, LIBSSH2_ERROR_BAD_SOCKET,
"failed creating socket");
s_un.sun_family = AF_UNIX;
strncpy(s_un.sun_path, path, sizeof(s_un.sun_path));
s_un.sun_path[sizeof(s_un.sun_path)-1] = 0; /* make sure there's a trailing
zero */
if(connect(agent->fd, (struct sockaddr*)(&s_un), sizeof(s_un)) != 0) {
close(agent->fd);
return _libssh2_error(agent->session, LIBSSH2_ERROR_AGENT_PROTOCOL,
"failed connecting with agent");
}
return LIBSSH2_ERROR_NONE;
}
#define RECV_SEND_ALL(func, socket, buffer, length, flags, abstract) \
do { \
size_t finished = 0; \
\
while(finished < length) { \
ssize_t rc; \
rc = func(socket, \
(char *)buffer + finished, length - finished, \
flags, abstract); \
if(rc < 0) \
return rc; \
\
finished += rc; \
} \
\
return finished; \
} while(0)
static ssize_t _send_all(LIBSSH2_SEND_FUNC(func), libssh2_socket_t socket,
const void *buffer, size_t length,
int flags, void **abstract)
{
RECV_SEND_ALL(func, socket, buffer, length, flags, abstract);
}
static ssize_t _recv_all(LIBSSH2_RECV_FUNC(func), libssh2_socket_t socket,
void *buffer, size_t length,
int flags, void **abstract)
{
RECV_SEND_ALL(func, socket, buffer, length, flags, abstract);
}
#undef RECV_SEND_ALL
static int
agent_transact_unix(LIBSSH2_AGENT *agent, agent_transaction_ctx_t transctx)
{
unsigned char buf[4];
int rc;
/* Send the length of the request */
if(transctx->state == agent_NB_state_request_created) {
_libssh2_htonu32(buf, (uint32_t)transctx->request_len);
rc = (int)_send_all(agent->session->send, agent->fd,
buf, sizeof(buf), 0,
&agent->session->abstract);
if(rc == -EAGAIN)
return LIBSSH2_ERROR_EAGAIN;
else if(rc < 0)
return _libssh2_error(agent->session, LIBSSH2_ERROR_SOCKET_SEND,
"agent send failed");
transctx->state = agent_NB_state_request_length_sent;
}
/* Send the request body */
if(transctx->state == agent_NB_state_request_length_sent) {
rc = (int)_send_all(agent->session->send, agent->fd,
transctx->request, transctx->request_len, 0,
&agent->session->abstract);
if(rc == -EAGAIN)
return LIBSSH2_ERROR_EAGAIN;
else if(rc < 0)
return _libssh2_error(agent->session, LIBSSH2_ERROR_SOCKET_SEND,
"agent send failed");
transctx->state = agent_NB_state_request_sent;
}
/* Receive the length of a response */
if(transctx->state == agent_NB_state_request_sent) {
rc = (int)_recv_all(agent->session->recv, agent->fd,
buf, sizeof(buf), 0,
&agent->session->abstract);
if(rc < 0) {
if(rc == -EAGAIN)
return LIBSSH2_ERROR_EAGAIN;
return _libssh2_error(agent->session, LIBSSH2_ERROR_SOCKET_RECV,
"agent recv failed");
}
transctx->response_len = _libssh2_ntohu32(buf);
transctx->response = LIBSSH2_ALLOC(agent->session,
transctx->response_len);
if(!transctx->response)
return LIBSSH2_ERROR_ALLOC;
transctx->state = agent_NB_state_response_length_received;
}
/* Receive the response body */
if(transctx->state == agent_NB_state_response_length_received) {
rc = (int)_recv_all(agent->session->recv, agent->fd,
transctx->response, transctx->response_len, 0,
&agent->session->abstract);
if(rc < 0) {
if(rc == -EAGAIN)
return LIBSSH2_ERROR_EAGAIN;
return _libssh2_error(agent->session, LIBSSH2_ERROR_SOCKET_SEND,
"agent recv failed");
}
transctx->state = agent_NB_state_response_received;
}
return 0;
}
static int
agent_disconnect_unix(LIBSSH2_AGENT *agent)
{
int ret;
ret = close(agent->fd);
if(ret != -1)
agent->fd = LIBSSH2_INVALID_SOCKET;
else
return _libssh2_error(agent->session, LIBSSH2_ERROR_SOCKET_DISCONNECT,
"failed closing the agent socket");
return LIBSSH2_ERROR_NONE;
}
static struct agent_ops agent_ops_unix = {
agent_connect_unix,
agent_transact_unix,
agent_disconnect_unix
};
#endif /* PF_UNIX */
#ifdef HAVE_WIN32_AGENTS
/* Code to talk to Pageant was taken from PuTTY.
*
* Portions copyright Robert de Bath, Joris van Rantwijk, Delian
* Delchev, Andreas Schultz, Jeroen Massar, Wez Furlong, Nicolas
* Barry, Justin Bradford, Ben Harris, Malcolm Smith, Ahmad Khalifa,
* Markus Kuhn, Colin Watson, and CORE SDI S.A.
*/
#define PAGEANT_COPYDATA_ID 0x804e50ba /* random goop */
#define PAGEANT_MAX_MSGLEN 8192
static int
agent_connect_pageant(LIBSSH2_AGENT *agent)
{
HWND hwnd;
hwnd = FindWindowA("Pageant", "Pageant");
if(!hwnd)
return _libssh2_error(agent->session, LIBSSH2_ERROR_AGENT_PROTOCOL,
"failed connecting agent");
agent->fd = 0; /* Mark as the connection has been established */
return LIBSSH2_ERROR_NONE;
}
static int
agent_transact_pageant(LIBSSH2_AGENT *agent, agent_transaction_ctx_t transctx)
{
HWND hwnd;
char mapname[23];
HANDLE filemap;
unsigned char *p;
unsigned char *p2;
LRESULT id;
COPYDATASTRUCT cds;
if(!transctx || 4 + transctx->request_len > PAGEANT_MAX_MSGLEN)
return _libssh2_error(agent->session, LIBSSH2_ERROR_INVAL,
"illegal input");
hwnd = FindWindowA("Pageant", "Pageant");
if(!hwnd)
return _libssh2_error(agent->session, LIBSSH2_ERROR_AGENT_PROTOCOL,
"found no pageant");
snprintf(mapname, sizeof(mapname),
"PageantRequest%08x", (unsigned)GetCurrentThreadId());
filemap = CreateFileMappingA(INVALID_HANDLE_VALUE, NULL, PAGE_READWRITE,
0, PAGEANT_MAX_MSGLEN, mapname);
if(!filemap || filemap == INVALID_HANDLE_VALUE)
return _libssh2_error(agent->session, LIBSSH2_ERROR_AGENT_PROTOCOL,
"failed setting up pageant filemap");
p2 = p = MapViewOfFile(filemap, FILE_MAP_WRITE, 0, 0, 0);
if(!p || !p2) {
CloseHandle(filemap);
return _libssh2_error(agent->session, LIBSSH2_ERROR_AGENT_PROTOCOL,
"failed to open pageant filemap for writing");
}
_libssh2_store_str(&p2, (const char *)transctx->request,
transctx->request_len);
cds.dwData = PAGEANT_COPYDATA_ID;
cds.cbData = (DWORD)(1 + strlen(mapname));
cds.lpData = mapname;
id = SendMessage(hwnd, WM_COPYDATA, (WPARAM) NULL, (LPARAM) &cds);
if(id > 0) {
transctx->response_len = _libssh2_ntohu32(p);
if(transctx->response_len > PAGEANT_MAX_MSGLEN) {
UnmapViewOfFile(p);
CloseHandle(filemap);
return _libssh2_error(agent->session, LIBSSH2_ERROR_AGENT_PROTOCOL,
"agent setup fail");
}
transctx->response = LIBSSH2_ALLOC(agent->session,
transctx->response_len);
if(!transctx->response) {
UnmapViewOfFile(p);
CloseHandle(filemap);
return _libssh2_error(agent->session, LIBSSH2_ERROR_ALLOC,
"agent malloc");
}
memcpy(transctx->response, p + 4, transctx->response_len);
}
UnmapViewOfFile(p);
CloseHandle(filemap);
return 0;
}
static int
agent_disconnect_pageant(LIBSSH2_AGENT *agent)
{
agent->fd = LIBSSH2_INVALID_SOCKET;
return 0;
}
static struct agent_ops agent_ops_pageant = {
agent_connect_pageant,
agent_transact_pageant,
agent_disconnect_pageant
};
#endif /* HAVE_WIN32_AGENTS */
static struct {
const char *name;
struct agent_ops *ops;
} supported_backends[] = {
#ifdef HAVE_WIN32_AGENTS
{"Pageant", &agent_ops_pageant},
{"OpenSSH", &agent_ops_openssh},
#endif /* HAVE_WIN32_AGENTS */
#ifdef PF_UNIX
{"Unix", &agent_ops_unix},
#endif /* PF_UNIX */
{NULL, NULL}
};
static int
agent_sign(LIBSSH2_SESSION *session, unsigned char **sig, size_t *sig_len,
const unsigned char *data, size_t data_len, void **abstract)
{
LIBSSH2_AGENT *agent = (LIBSSH2_AGENT *) (*abstract);
agent_transaction_ctx_t transctx = &agent->transctx;
struct agent_publickey *identity = agent->identity;
ssize_t len = 1 + 4 + identity->external.blob_len + 4 + data_len + 4;
ssize_t method_len;
unsigned char *s;
int rc;
unsigned char *method_name = NULL;
uint32_t sign_flags = 0;
ssize_t plain_len;
/* Create a request to sign the data */
if(transctx->state == agent_NB_state_init) {
s = transctx->request = LIBSSH2_ALLOC(session, len);
if(!transctx->request)
return _libssh2_error(session, LIBSSH2_ERROR_ALLOC,
"out of memory");
*s++ = SSH2_AGENTC_SIGN_REQUEST;
/* key blob */
_libssh2_store_str(&s, (const char *)identity->external.blob,
identity->external.blob_len);
/* data */
_libssh2_store_str(&s, (const char *)data, data_len);
/* flags */
if(session->userauth_pblc_method_len > 0 &&
session->userauth_pblc_method) {
if(session->userauth_pblc_method_len == 12 &&
!memcmp(session->userauth_pblc_method, "rsa-sha2-512", 12)) {
sign_flags = SSH_AGENT_RSA_SHA2_512;
}
else if(session->userauth_pblc_method_len == 12 &&
!memcmp(session->userauth_pblc_method, "rsa-sha2-256", 12)) {
sign_flags = SSH_AGENT_RSA_SHA2_256;
}
}
_libssh2_store_u32(&s, sign_flags);
transctx->request_len = s - transctx->request;
transctx->send_recv_total = 0;
transctx->state = agent_NB_state_request_created;
}
/* Make sure to be re-called as a result of EAGAIN. */
if(*transctx->request != SSH2_AGENTC_SIGN_REQUEST)
return _libssh2_error(session, LIBSSH2_ERROR_BAD_USE,
"illegal request");
if(!agent->ops)
/* if no agent has been connected, bail out */
return _libssh2_error(session, LIBSSH2_ERROR_BAD_USE,
"agent not connected");
rc = agent->ops->transact(agent, transctx);
if(rc) {
goto error;
}
LIBSSH2_FREE(session, transctx->request);
transctx->request = NULL;
len = transctx->response_len;
s = transctx->response;
len--;
if(len < 0) {
rc = LIBSSH2_ERROR_AGENT_PROTOCOL;
goto error;
}
if(*s != SSH2_AGENT_SIGN_RESPONSE) {
rc = LIBSSH2_ERROR_AGENT_PROTOCOL;
goto error;
}
s++;
/* Skip the entire length of the signature */
len -= 4;
if(len < 0) {
rc = LIBSSH2_ERROR_AGENT_PROTOCOL;
goto error;
}
s += 4;
/* Skip signing method */
len -= 4;
if(len < 0) {
rc = LIBSSH2_ERROR_AGENT_PROTOCOL;
goto error;
}
method_len = _libssh2_ntohu32(s);
s += 4;
len -= method_len;
if(len < 0) {
rc = LIBSSH2_ERROR_AGENT_PROTOCOL;
goto error;
}
/* method name */
method_name = LIBSSH2_ALLOC(session, method_len);
if(!method_name) {
rc = LIBSSH2_ERROR_ALLOC;
goto error;
}
memcpy(method_name, s, method_len);
s += method_len;
plain_len = plain_method((char *)session->userauth_pblc_method,
session->userauth_pblc_method_len);
/* check to see if we match requested */
if(((size_t)method_len != session->userauth_pblc_method_len &&
method_len != plain_len) ||
memcmp(method_name, session->userauth_pblc_method, method_len)) {
_libssh2_debug((session,
LIBSSH2_TRACE_KEX,
"Agent sign method %.*s",
(int)method_len, method_name));
rc = LIBSSH2_ERROR_ALGO_UNSUPPORTED;
goto error;
}
/* Read the signature */
len -= 4;
if(len < 0) {
rc = LIBSSH2_ERROR_AGENT_PROTOCOL;
goto error;
}
*sig_len = _libssh2_ntohu32(s);
s += 4;
len -= *sig_len;
if(len < 0) {
rc = LIBSSH2_ERROR_AGENT_PROTOCOL;
goto error;
}
*sig = LIBSSH2_ALLOC(session, *sig_len);
if(!*sig) {
rc = LIBSSH2_ERROR_ALLOC;
goto error;
}
memcpy(*sig, s, *sig_len);
error:
if(method_name)
LIBSSH2_FREE(session, method_name);
LIBSSH2_FREE(session, transctx->request);
transctx->request = NULL;
LIBSSH2_FREE(session, transctx->response);
transctx->response = NULL;
transctx->state = agent_NB_state_init;
return _libssh2_error(session, rc, "agent sign failure");
}
static int
agent_list_identities(LIBSSH2_AGENT *agent)
{
agent_transaction_ctx_t transctx = &agent->transctx;
ssize_t len, num_identities;
unsigned char *s;
int rc;
unsigned char c = SSH2_AGENTC_REQUEST_IDENTITIES;
/* Create a request to list identities */
if(transctx->state == agent_NB_state_init) {
transctx->request = &c;
transctx->request_len = 1;
transctx->send_recv_total = 0;
transctx->state = agent_NB_state_request_created;
}
/* Make sure to be re-called as a result of EAGAIN. */
if(*transctx->request != SSH2_AGENTC_REQUEST_IDENTITIES)
return _libssh2_error(agent->session, LIBSSH2_ERROR_BAD_USE,
"illegal agent request");
if(!agent->ops)
/* if no agent has been connected, bail out */
return _libssh2_error(agent->session, LIBSSH2_ERROR_BAD_USE,
"agent not connected");
rc = agent->ops->transact(agent, transctx);
if(rc) {
LIBSSH2_FREE(agent->session, transctx->response);
transctx->response = NULL;
return rc;
}
transctx->request = NULL;
len = transctx->response_len;
s = transctx->response;
len--;
if(len < 0) {
rc = LIBSSH2_ERROR_AGENT_PROTOCOL;
goto error;
}
if(*s != SSH2_AGENT_IDENTITIES_ANSWER) {
rc = LIBSSH2_ERROR_AGENT_PROTOCOL;
goto error;
}
s++;
/* Read the length of identities */
len -= 4;
if(len < 0) {
rc = LIBSSH2_ERROR_AGENT_PROTOCOL;
goto error;
}
num_identities = _libssh2_ntohu32(s);
s += 4;
while(num_identities--) {
struct agent_publickey *identity;
size_t comment_len;
/* Read the length of the blob */
len -= 4;
if(len < 0) {
rc = LIBSSH2_ERROR_AGENT_PROTOCOL;
goto error;
}
identity = LIBSSH2_ALLOC(agent->session, sizeof(*identity));
if(!identity) {
rc = LIBSSH2_ERROR_ALLOC;
goto error;
}
identity->external.blob_len = _libssh2_ntohu32(s);
s += 4;
/* Read the blob */
len -= identity->external.blob_len;
if(len < 0) {
rc = LIBSSH2_ERROR_AGENT_PROTOCOL;
LIBSSH2_FREE(agent->session, identity);
goto error;
}
identity->external.blob = LIBSSH2_ALLOC(agent->session,
identity->external.blob_len);
if(!identity->external.blob) {
rc = LIBSSH2_ERROR_ALLOC;
LIBSSH2_FREE(agent->session, identity);
goto error;
}
memcpy(identity->external.blob, s, identity->external.blob_len);
s += identity->external.blob_len;
/* Read the length of the comment */
len -= 4;
if(len < 0) {
rc = LIBSSH2_ERROR_AGENT_PROTOCOL;
LIBSSH2_FREE(agent->session, identity->external.blob);
LIBSSH2_FREE(agent->session, identity);
goto error;
}
comment_len = _libssh2_ntohu32(s);
s += 4;
if(comment_len > (size_t)len) {
rc = LIBSSH2_ERROR_AGENT_PROTOCOL;
LIBSSH2_FREE(agent->session, identity->external.blob);
LIBSSH2_FREE(agent->session, identity);
goto error;
}
/* Read the comment */
len -= comment_len;
identity->external.comment = LIBSSH2_ALLOC(agent->session,
comment_len + 1);
if(!identity->external.comment) {
rc = LIBSSH2_ERROR_ALLOC;
LIBSSH2_FREE(agent->session, identity->external.blob);
LIBSSH2_FREE(agent->session, identity);
goto error;
}
identity->external.comment[comment_len] = '\0';
memcpy(identity->external.comment, s, comment_len);
s += comment_len;
_libssh2_list_add(&agent->head, &identity->node);
}
error:
LIBSSH2_FREE(agent->session, transctx->response);
transctx->response = NULL;
return _libssh2_error(agent->session, rc,
"agent list id failed");
}
static void
agent_free_identities(LIBSSH2_AGENT *agent)
{
struct agent_publickey *node;
struct agent_publickey *next;
for(node = _libssh2_list_first(&agent->head); node; node = next) {
next = _libssh2_list_next(&node->node);
LIBSSH2_FREE(agent->session, node->external.blob);
LIBSSH2_FREE(agent->session, node->external.comment);
LIBSSH2_FREE(agent->session, node);
}
_libssh2_list_init(&agent->head);
}
#define AGENT_PUBLICKEY_MAGIC 0x3bdefed2
/*
* agent_publickey_to_external
*
* Copies data from the internal to the external representation struct.
*
*/
static struct libssh2_agent_publickey *
agent_publickey_to_external(struct agent_publickey *node)
{
struct libssh2_agent_publickey *ext = &node->external;
ext->magic = AGENT_PUBLICKEY_MAGIC;
ext->node = node;
return ext;
}
/*
* libssh2_agent_init
*
* Init an ssh-agent handle. Returns the pointer to the handle.
*
*/
LIBSSH2_API LIBSSH2_AGENT *
libssh2_agent_init(LIBSSH2_SESSION *session)
{
LIBSSH2_AGENT *agent;
agent = LIBSSH2_CALLOC(session, sizeof(*agent));
if(!agent) {
_libssh2_error(session, LIBSSH2_ERROR_ALLOC,
"Unable to allocate space for agent connection");
return NULL;
}
agent->fd = LIBSSH2_INVALID_SOCKET;
agent->session = session;
agent->identity_agent_path = NULL;
_libssh2_list_init(&agent->head);
#ifdef HAVE_WIN32_AGENTS
agent->pipe = INVALID_HANDLE_VALUE;
memset(&agent->overlapped, 0, sizeof(OVERLAPPED));
agent->pending_io = FALSE;
#endif
return agent;
}
/*
* libssh2_agent_connect
*
* Connect to an ssh-agent.
*
* Returns 0 if succeeded, or a negative value for error.
*/
LIBSSH2_API int
libssh2_agent_connect(LIBSSH2_AGENT *agent)
{
int i, rc = -1;
for(i = 0; supported_backends[i].name; i++) {
agent->ops = supported_backends[i].ops;
rc = (agent->ops->connect)(agent);
if(!rc)
return 0;
}
return rc;
}
/*
* libssh2_agent_list_identities
*
* Request ssh-agent to list identities.
*
* Returns 0 if succeeded, or a negative value for error.
*/
LIBSSH2_API int
libssh2_agent_list_identities(LIBSSH2_AGENT *agent)
{
memset(&agent->transctx, 0, sizeof(agent->transctx));
/* Abandon the last fetched identities */
agent_free_identities(agent);
return agent_list_identities(agent);
}
/*
* libssh2_agent_get_identity
*
* Traverse the internal list of public keys. Pass NULL to 'prev' to get
* the first one. Or pass a pointer to the previously returned one to get the
* next.
*
* Returns:
* 0 if a fine public key was stored in 'store'
* 1 if end of public keys
* [negative] on errors
*/
LIBSSH2_API int
libssh2_agent_get_identity(LIBSSH2_AGENT *agent,
struct libssh2_agent_publickey **ext,
struct libssh2_agent_publickey *oprev)
{
struct agent_publickey *node;
if(oprev && oprev->node) {
/* we have a starting point */
struct agent_publickey *prev = oprev->node;
/* get the next node in the list */
node = _libssh2_list_next(&prev->node);
}
else
node = _libssh2_list_first(&agent->head);
if(!node)
/* no (more) node */
return 1;
*ext = agent_publickey_to_external(node);
return 0;
}
/*
* libssh2_agent_userauth
*
* Do publickey user authentication with the help of ssh-agent.
*
* Returns 0 if succeeded, or a negative value for error.
*/
LIBSSH2_API int
libssh2_agent_userauth(LIBSSH2_AGENT *agent,
const char *username,
struct libssh2_agent_publickey *identity)
{
void *abstract = agent;
int rc;
if(agent->session->userauth_pblc_state == libssh2_NB_state_idle) {
memset(&agent->transctx, 0, sizeof(agent->transctx));
agent->identity = identity->node;
}
BLOCK_ADJUST(rc, agent->session,
_libssh2_userauth_publickey(agent->session, username,
strlen(username),
identity->blob,
identity->blob_len,
agent_sign,
&abstract));
return rc;
}
/*
* libssh2_agent_sign
*
* Sign a payload using a system-installed ssh-agent.
*
* Returns 0 if succeeded, or a negative value for error.
*/
LIBSSH2_API int
libssh2_agent_sign(LIBSSH2_AGENT *agent,
struct libssh2_agent_publickey *identity,
unsigned char **sig,
size_t *s_len,
const unsigned char *data,
size_t d_len,
const char *method,
unsigned int method_len)
{
void *abstract = agent;
int rc;
uint32_t methodLen;
if(agent->session->userauth_pblc_state == libssh2_NB_state_idle) {
memset(&agent->transctx, 0, sizeof(agent->transctx));
agent->identity = identity->node;
}
if(identity->blob_len < sizeof(uint32_t)) {
return LIBSSH2_ERROR_BUFFER_TOO_SMALL;
}
methodLen = _libssh2_ntohu32(identity->blob);
if(identity->blob_len < sizeof(uint32_t) + methodLen) {
return LIBSSH2_ERROR_BUFFER_TOO_SMALL;
}
agent->session->userauth_pblc_method_len = method_len;
agent->session->userauth_pblc_method = LIBSSH2_ALLOC(agent->session,
method_len);
memcpy(agent->session->userauth_pblc_method, method, methodLen);
rc = agent_sign(agent->session, sig, s_len, data, d_len, &abstract);
LIBSSH2_FREE(agent->session, agent->session->userauth_pblc_method);
agent->session->userauth_pblc_method = NULL;
agent->session->userauth_pblc_method_len = 0;
return rc;
}
/*
* libssh2_agent_disconnect
*
* Close a connection to an ssh-agent.
*
* Returns 0 if succeeded, or a negative value for error.
*/
LIBSSH2_API int
libssh2_agent_disconnect(LIBSSH2_AGENT *agent)
{
if(agent->ops && agent->fd != LIBSSH2_INVALID_SOCKET)
return agent->ops->disconnect(agent);
return 0;
}
/*
* libssh2_agent_free
*
* Free an ssh-agent handle. This function also frees the internal
* collection of public keys.
*/
LIBSSH2_API void
libssh2_agent_free(LIBSSH2_AGENT *agent)
{
/* Allow connection freeing when the socket has lost its connection */
if(agent->fd != LIBSSH2_INVALID_SOCKET) {
libssh2_agent_disconnect(agent);
}
if(agent->identity_agent_path)
LIBSSH2_FREE(agent->session, agent->identity_agent_path);
agent_free_identities(agent);
LIBSSH2_FREE(agent->session, agent);
}
/*
* libssh2_agent_set_identity_path
*
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