541 lines
12 KiB
C
541 lines
12 KiB
C
/*
|
|
* Copyright (C) 2008 Martin Willi
|
|
* Hochschule fuer Technik Rapperswil
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify it
|
|
* under the terms of the GNU General Public License as published by the
|
|
* Free Software Foundation; either version 2 of the License, or (at your
|
|
* option) any later version. See <http://www.fsf.org/copyleft/gpl.txt>.
|
|
*
|
|
* This program is distributed in the hope that it will be useful, but
|
|
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
|
|
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
|
|
* for more details.
|
|
*
|
|
* $Id$
|
|
*/
|
|
|
|
#include "agent_private_key.h"
|
|
|
|
#include <stdlib.h>
|
|
#include <unistd.h>
|
|
#include <sys/types.h>
|
|
#include <sys/socket.h>
|
|
#include <sys/un.h>
|
|
#include <arpa/inet.h>
|
|
#include <errno.h>
|
|
|
|
#include <library.h>
|
|
#include <chunk.h>
|
|
#include <debug.h>
|
|
#include <asn1/asn1.h>
|
|
#include <asn1/oid.h>
|
|
|
|
#ifndef UNIX_PATH_MAX
|
|
#define UNIX_PATH_MAX 108
|
|
#endif /* UNIX_PATH_MAX */
|
|
|
|
typedef struct private_agent_private_key_t private_agent_private_key_t;
|
|
typedef enum agent_msg_type_t agent_msg_type_t;
|
|
|
|
/**
|
|
* Private data of a agent_private_key_t object.
|
|
*/
|
|
struct private_agent_private_key_t {
|
|
/**
|
|
* Public interface for this signer.
|
|
*/
|
|
agent_private_key_t public;
|
|
|
|
/**
|
|
* ssh-agent unix socket connection
|
|
*/
|
|
int socket;
|
|
|
|
/**
|
|
* key identity blob in ssh format
|
|
*/
|
|
chunk_t key;
|
|
|
|
/**
|
|
* keysize in bytes
|
|
*/
|
|
size_t key_size;
|
|
|
|
/**
|
|
* Keyid formed as a SHA-1 hash of a publicKey object
|
|
*/
|
|
identification_t* keyid;
|
|
|
|
/**
|
|
* Keyid formed as a SHA-1 hash of a publicKeyInfo object
|
|
*/
|
|
identification_t* keyid_info;
|
|
|
|
/**
|
|
* reference count
|
|
*/
|
|
refcount_t ref;
|
|
};
|
|
|
|
/**
|
|
* Message types for ssh-agent protocol
|
|
*/
|
|
enum agent_msg_type_t {
|
|
SSH_AGENT_FAILURE = 5,
|
|
SSH_AGENT_SUCCESS = 6,
|
|
SSH_AGENT_ID_REQUEST = 11,
|
|
SSH_AGENT_ID_RESPONSE = 12,
|
|
SSH_AGENT_SIGN_REQUEST = 13,
|
|
SSH_AGENT_SIGN_RESPONSE = 14,
|
|
};
|
|
|
|
/**
|
|
* read a byte from a blob
|
|
*/
|
|
static u_char read_byte(chunk_t *blob)
|
|
{
|
|
u_char val;
|
|
|
|
if (blob->len < sizeof(u_char))
|
|
{
|
|
return 0;
|
|
}
|
|
val = *(blob->ptr);
|
|
*blob = chunk_skip(*blob, sizeof(u_char));
|
|
return val;
|
|
}
|
|
|
|
/**
|
|
* read a u_int32_t from a blob
|
|
*/
|
|
static u_int32_t read_uint32(chunk_t *blob)
|
|
{
|
|
u_int32_t val;
|
|
|
|
if (blob->len < sizeof(u_int32_t))
|
|
{
|
|
return 0;
|
|
}
|
|
val = ntohl(*(u_int32_t*)blob->ptr);
|
|
*blob = chunk_skip(*blob, sizeof(u_int32_t));
|
|
return val;
|
|
}
|
|
|
|
/**
|
|
* read a ssh-agent "string" length/value from a blob
|
|
*/
|
|
static chunk_t read_string(chunk_t *blob)
|
|
{
|
|
int len;
|
|
chunk_t str;
|
|
|
|
len = read_uint32(blob);
|
|
if (len > blob->len)
|
|
{
|
|
return chunk_empty;
|
|
}
|
|
str = chunk_create(blob->ptr, len);
|
|
*blob = chunk_skip(*blob, + len);
|
|
return str;
|
|
}
|
|
|
|
/**
|
|
* open socket connection to the ssh-agent
|
|
*/
|
|
static int open_connection(char *path)
|
|
{
|
|
struct sockaddr_un addr;
|
|
int s;
|
|
|
|
s = socket(AF_UNIX, SOCK_STREAM, 0);
|
|
if (s == -1)
|
|
{
|
|
DBG1("opening ssh-agent socket %s failed: %s:", path, strerror(errno));
|
|
return -1;
|
|
}
|
|
|
|
addr.sun_family = AF_UNIX;
|
|
addr.sun_path[UNIX_PATH_MAX - 1] = '\0';
|
|
strncpy(addr.sun_path, path, UNIX_PATH_MAX - 1);
|
|
|
|
if (connect(s, (struct sockaddr*)&addr, SUN_LEN(&addr)) != 0)
|
|
{
|
|
DBG1("connecting to ssh-agent socket failed: %s", strerror(errno));
|
|
close(s);
|
|
return -1;
|
|
}
|
|
return s;
|
|
}
|
|
|
|
/**
|
|
* Get the first usable key from the agent
|
|
*/
|
|
static bool read_key(private_agent_private_key_t *this)
|
|
{
|
|
int len, count;
|
|
char buf[2048];
|
|
chunk_t blob = chunk_from_buf(buf), key, type, tmp;
|
|
|
|
len = htonl(1);
|
|
write(this->socket, &len, sizeof(len));
|
|
buf[0] = SSH_AGENT_ID_REQUEST;
|
|
write(this->socket, &buf, 1);
|
|
|
|
blob.len = read(this->socket, blob.ptr, blob.len);
|
|
|
|
if (blob.len < sizeof(u_int32_t) + sizeof(u_char) ||
|
|
read_uint32(&blob) != blob.len ||
|
|
read_byte(&blob) != SSH_AGENT_ID_RESPONSE)
|
|
{
|
|
DBG1("received invalid ssh-agent identity response");
|
|
return FALSE;
|
|
}
|
|
count = read_uint32(&blob);
|
|
|
|
while (blob.len)
|
|
{
|
|
key = read_string(&blob);
|
|
if (key.len)
|
|
{
|
|
tmp = key;
|
|
type = read_string(&tmp);
|
|
read_string(&tmp);
|
|
tmp = read_string(&tmp);
|
|
if (type.len && strneq("ssh-rsa", type.ptr, type.len) &&
|
|
tmp.len >= 512/8)
|
|
{
|
|
this->key = chunk_clone(key);
|
|
this->key_size = tmp.len;
|
|
if (tmp.ptr[0] == 0)
|
|
{
|
|
this->key_size--;
|
|
}
|
|
return TRUE;
|
|
}
|
|
continue;
|
|
}
|
|
break;
|
|
}
|
|
return FALSE;
|
|
}
|
|
|
|
/**
|
|
* Implementation of agent_private_key.destroy.
|
|
*/
|
|
static bool sign(private_agent_private_key_t *this, signature_scheme_t scheme,
|
|
chunk_t data, chunk_t *signature)
|
|
{
|
|
u_int32_t len, flags;
|
|
char buf[2048];
|
|
chunk_t blob = chunk_from_buf(buf);
|
|
|
|
if (scheme != SIGN_DEFAULT && scheme != SIGN_RSA_EMSA_PKCS1_SHA1)
|
|
{
|
|
DBG1("signature scheme %N not supported by ssh-agent",
|
|
signature_scheme_names, scheme);
|
|
return FALSE;
|
|
}
|
|
|
|
len = htonl(1 + sizeof(u_int32_t) * 3 + this->key.len + data.len);
|
|
write(this->socket, &len, sizeof(len));
|
|
buf[0] = SSH_AGENT_SIGN_REQUEST;
|
|
write(this->socket, &buf, 1);
|
|
|
|
len = htonl(this->key.len);
|
|
write(this->socket, &len, sizeof(len));
|
|
write(this->socket, this->key.ptr, this->key.len);
|
|
|
|
len = htonl(data.len);
|
|
write(this->socket, &len, sizeof(len));
|
|
write(this->socket, data.ptr, data.len);
|
|
|
|
flags = htonl(0);
|
|
write(this->socket, &flags, sizeof(flags));
|
|
|
|
blob.len = read(this->socket, blob.ptr, blob.len);
|
|
if (blob.len < sizeof(u_int32_t) + sizeof(u_char) ||
|
|
read_uint32(&blob) != blob.len ||
|
|
read_byte(&blob) != SSH_AGENT_SIGN_RESPONSE)
|
|
{
|
|
DBG1("received invalid ssh-agent signature response");
|
|
return FALSE;
|
|
}
|
|
/* parse length */
|
|
blob = read_string(&blob);
|
|
/* skip sig type */
|
|
read_string(&blob);
|
|
/* parse length */
|
|
blob = read_string(&blob);
|
|
if (!blob.len)
|
|
{
|
|
DBG1("received invalid ssh-agent signature response");
|
|
return FALSE;
|
|
}
|
|
*signature = chunk_clone(blob);
|
|
return TRUE;
|
|
}
|
|
|
|
/**
|
|
* Implementation of agent_private_key.destroy.
|
|
*/
|
|
static key_type_t get_type(private_agent_private_key_t *this)
|
|
{
|
|
return KEY_RSA;
|
|
}
|
|
|
|
/**
|
|
* Implementation of agent_private_key.destroy.
|
|
*/
|
|
static bool decrypt(private_agent_private_key_t *this,
|
|
chunk_t crypto, chunk_t *plain)
|
|
{
|
|
DBG1("private key decryption not supported by ssh-agent");
|
|
return FALSE;
|
|
}
|
|
|
|
/**
|
|
* Implementation of agent_private_key.destroy.
|
|
*/
|
|
static size_t get_keysize(private_agent_private_key_t *this)
|
|
{
|
|
return this->key_size;
|
|
}
|
|
|
|
/**
|
|
* Implementation of agent_private_key.destroy.
|
|
*/
|
|
static identification_t* get_id(private_agent_private_key_t *this,
|
|
id_type_t type)
|
|
{
|
|
switch (type)
|
|
{
|
|
case ID_PUBKEY_INFO_SHA1:
|
|
return this->keyid_info;
|
|
case ID_PUBKEY_SHA1:
|
|
return this->keyid;
|
|
default:
|
|
return NULL;
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Implementation of agent_private_key.get_public_key.
|
|
*/
|
|
static public_key_t* get_public_key(private_agent_private_key_t *this)
|
|
{
|
|
chunk_t key, n, e, encoded;
|
|
public_key_t *public;
|
|
|
|
key = this->key;
|
|
read_string(&key);
|
|
e = read_string(&key);
|
|
n = read_string(&key);
|
|
encoded = asn1_wrap(ASN1_SEQUENCE, "mm",
|
|
asn1_wrap(ASN1_INTEGER, "c", n),
|
|
asn1_wrap(ASN1_INTEGER, "c", e));
|
|
|
|
public = lib->creds->create(lib->creds, CRED_PUBLIC_KEY, KEY_RSA,
|
|
BUILD_BLOB_ASN1_DER, encoded, BUILD_END);
|
|
free(encoded.ptr);
|
|
return public;
|
|
}
|
|
|
|
/**
|
|
* Implementation of agent_private_key.belongs_to.
|
|
*/
|
|
static bool belongs_to(private_agent_private_key_t *this, public_key_t *public)
|
|
{
|
|
identification_t *keyid;
|
|
|
|
if (public->get_type(public) != KEY_RSA)
|
|
{
|
|
return FALSE;
|
|
}
|
|
keyid = public->get_id(public, ID_PUBKEY_SHA1);
|
|
if (keyid && keyid->equals(keyid, this->keyid))
|
|
{
|
|
return TRUE;
|
|
}
|
|
keyid = public->get_id(public, ID_PUBKEY_INFO_SHA1);
|
|
if (keyid && keyid->equals(keyid, this->keyid_info))
|
|
{
|
|
return TRUE;
|
|
}
|
|
return FALSE;
|
|
}
|
|
|
|
/**
|
|
* Build the RSA key identifier from n and e using SHA1 hashed publicKey(Info).
|
|
*/
|
|
static bool build_ids(private_agent_private_key_t *this)
|
|
{
|
|
chunk_t publicKeyInfo, publicKey, hash, key, n, e;
|
|
hasher_t *hasher;
|
|
|
|
key = this->key;
|
|
e = read_string(&key);
|
|
n = read_string(&key);
|
|
|
|
hasher = lib->crypto->create_hasher(lib->crypto, HASH_SHA1);
|
|
if (hasher == NULL)
|
|
{
|
|
DBG1("SHA1 hash algorithm not supported, unable to use RSA");
|
|
return FALSE;
|
|
}
|
|
publicKey = asn1_wrap(ASN1_SEQUENCE, "cc", n, e);
|
|
hasher->allocate_hash(hasher, publicKey, &hash);
|
|
this->keyid = identification_create_from_encoding(ID_PUBKEY_SHA1, hash);
|
|
chunk_free(&hash);
|
|
|
|
publicKeyInfo = asn1_wrap(ASN1_SEQUENCE, "cm",
|
|
asn1_algorithmIdentifier(OID_RSA_ENCRYPTION),
|
|
asn1_bitstring("m", publicKey));
|
|
hasher->allocate_hash(hasher, publicKeyInfo, &hash);
|
|
this->keyid_info = identification_create_from_encoding(ID_PUBKEY_INFO_SHA1, hash);
|
|
chunk_free(&hash);
|
|
|
|
hasher->destroy(hasher);
|
|
chunk_free(&publicKeyInfo);
|
|
return TRUE;
|
|
}
|
|
|
|
/**
|
|
* Implementation of private_key_t.get_encoding.
|
|
*/
|
|
static chunk_t get_encoding(private_agent_private_key_t *this)
|
|
{
|
|
return chunk_empty;
|
|
}
|
|
|
|
/**
|
|
* Implementation of agent_private_key.get_ref.
|
|
*/
|
|
static private_agent_private_key_t* get_ref(private_agent_private_key_t *this)
|
|
{
|
|
ref_get(&this->ref);
|
|
return this;
|
|
}
|
|
|
|
/**
|
|
* Implementation of agent_private_key.destroy.
|
|
*/
|
|
static void destroy(private_agent_private_key_t *this)
|
|
{
|
|
if (ref_put(&this->ref))
|
|
{
|
|
close(this->socket);
|
|
DESTROY_IF(this->keyid);
|
|
DESTROY_IF(this->keyid_info);
|
|
free(this->key.ptr);
|
|
free(this);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Internal constructor
|
|
*/
|
|
static agent_private_key_t *agent_private_key_create(char *path)
|
|
{
|
|
private_agent_private_key_t *this = malloc_thing(private_agent_private_key_t);
|
|
|
|
this->public.interface.get_type = (key_type_t (*)(private_key_t *this))get_type;
|
|
this->public.interface.sign = (bool (*)(private_key_t *this, signature_scheme_t scheme, chunk_t data, chunk_t *signature))sign;
|
|
this->public.interface.decrypt = (bool (*)(private_key_t *this, chunk_t crypto, chunk_t *plain))decrypt;
|
|
this->public.interface.get_keysize = (size_t (*) (private_key_t *this))get_keysize;
|
|
this->public.interface.get_id = (identification_t* (*) (private_key_t *this,id_type_t))get_id;
|
|
this->public.interface.get_public_key = (public_key_t* (*)(private_key_t *this))get_public_key;
|
|
this->public.interface.belongs_to = (bool (*) (private_key_t *this, public_key_t *public))belongs_to;
|
|
this->public.interface.get_encoding = (chunk_t(*)(private_key_t*))get_encoding;
|
|
this->public.interface.get_ref = (private_key_t* (*)(private_key_t *this))get_ref;
|
|
this->public.interface.destroy = (void (*)(private_key_t *this))destroy;
|
|
|
|
this->socket = open_connection(path);
|
|
if (this->socket < 0)
|
|
{
|
|
free(this);
|
|
return NULL;
|
|
}
|
|
this->keyid = NULL;
|
|
this->keyid_info = NULL;
|
|
this->ref = 1;
|
|
if (!read_key(this) || !build_ids(this))
|
|
{
|
|
destroy(this);
|
|
return NULL;
|
|
}
|
|
return &this->public;
|
|
}
|
|
|
|
typedef struct private_builder_t private_builder_t;
|
|
/**
|
|
* Builder implementation for key loading/generation
|
|
*/
|
|
struct private_builder_t {
|
|
/** implements the builder interface */
|
|
builder_t public;
|
|
/** loaded/generated private key */
|
|
agent_private_key_t *key;
|
|
};
|
|
|
|
/**
|
|
* Implementation of builder_t.build
|
|
*/
|
|
static agent_private_key_t *build(private_builder_t *this)
|
|
{
|
|
agent_private_key_t *key = this->key;
|
|
|
|
free(this);
|
|
return key;
|
|
}
|
|
|
|
/**
|
|
* Implementation of builder_t.add
|
|
*/
|
|
static void add(private_builder_t *this, builder_part_t part, ...)
|
|
{
|
|
va_list args;
|
|
|
|
if (this->key)
|
|
{
|
|
DBG1("ignoring surplus build part %N", builder_part_names, part);
|
|
return;
|
|
}
|
|
|
|
switch (part)
|
|
{
|
|
case BUILD_AGENT_SOCKET:
|
|
{
|
|
va_start(args, part);
|
|
this->key = agent_private_key_create(va_arg(args, char*));
|
|
va_end(args);
|
|
break;
|
|
}
|
|
default:
|
|
DBG1("ignoring unsupported build part %N", builder_part_names, part);
|
|
break;
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Builder construction function
|
|
*/
|
|
builder_t *agent_private_key_builder(key_type_t type)
|
|
{
|
|
private_builder_t *this;
|
|
|
|
if (type != KEY_RSA)
|
|
{
|
|
return NULL;
|
|
}
|
|
|
|
this = malloc_thing(private_builder_t);
|
|
|
|
this->key = NULL;
|
|
this->public.add = (void(*)(builder_t *this, builder_part_t part, ...))add;
|
|
this->public.build = (void*(*)(builder_t *this))build;
|
|
|
|
return &this->public;
|
|
}
|
|
|