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NetBSD/crypto/dist/ssh/ssh-agent.c

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/* $NetBSD: ssh-agent.c,v 1.13 2001/12/06 03:54:06 itojun Exp $ */
/* $OpenBSD: ssh-agent.c,v 1.74 2001/12/05 10:06:12 deraadt Exp $ */
/*
* Author: Tatu Ylonen <ylo@cs.hut.fi>
* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
* All rights reserved
* The authentication agent program.
*
* 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.
*
* 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"
RCSID("$OpenBSD: ssh-agent.c,v 1.74 2001/12/05 10:06:12 deraadt Exp $");
#include <openssl/evp.h>
#include <openssl/md5.h>
#include "ssh.h"
#include "rsa.h"
#include "buffer.h"
#include "bufaux.h"
#include "xmalloc.h"
#include "packet.h"
#include "getput.h"
#include "mpaux.h"
#include "key.h"
#include "authfd.h"
#include "cipher.h"
#include "kex.h"
#include "compat.h"
#include "log.h"
#ifdef SMARTCARD
#include <openssl/engine.h>
#include "scard.h"
#endif
typedef enum {
AUTH_UNUSED,
AUTH_SOCKET,
AUTH_CONNECTION
} sock_type;
typedef struct {
int fd;
sock_type type;
Buffer input;
Buffer output;
} SocketEntry;
u_int sockets_alloc = 0;
SocketEntry *sockets = NULL;
typedef struct {
Key *key;
char *comment;
} Identity;
typedef struct {
int nentries;
Identity *identities;
} Idtab;
/* private key table, one per protocol version */
Idtab idtable[3];
int max_fd = 0;
/* pid of shell == parent of agent */
pid_t parent_pid = -1;
/* pathname and directory for AUTH_SOCKET */
char socket_name[1024];
char socket_dir[1024];
extern char *__progname;
static void
idtab_init(void)
{
int i;
for (i = 0; i <=2; i++) {
idtable[i].identities = NULL;
idtable[i].nentries = 0;
}
}
/* return private key table for requested protocol version */
static Idtab *
idtab_lookup(int version)
{
if (version < 1 || version > 2)
fatal("internal error, bad protocol version %d", version);
return &idtable[version];
}
/* return matching private key for given public key */
static Key *
lookup_private_key(Key *key, int *idx, int version)
{
int i;
Idtab *tab = idtab_lookup(version);
for (i = 0; i < tab->nentries; i++) {
if (key_equal(key, tab->identities[i].key)) {
if (idx != NULL)
*idx = i;
return tab->identities[i].key;
}
}
return NULL;
}
/* send list of supported public keys to 'client' */
static void
process_request_identities(SocketEntry *e, int version)
{
Idtab *tab = idtab_lookup(version);
Buffer msg;
int i;
buffer_init(&msg);
buffer_put_char(&msg, (version == 1) ?
SSH_AGENT_RSA_IDENTITIES_ANSWER : SSH2_AGENT_IDENTITIES_ANSWER);
buffer_put_int(&msg, tab->nentries);
for (i = 0; i < tab->nentries; i++) {
Identity *id = &tab->identities[i];
if (id->key->type == KEY_RSA1) {
buffer_put_int(&msg, BN_num_bits(id->key->rsa->n));
buffer_put_bignum(&msg, id->key->rsa->e);
buffer_put_bignum(&msg, id->key->rsa->n);
} else {
u_char *blob;
u_int blen;
key_to_blob(id->key, &blob, &blen);
buffer_put_string(&msg, blob, blen);
xfree(blob);
}
buffer_put_cstring(&msg, id->comment);
}
buffer_put_int(&e->output, buffer_len(&msg));
buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg));
buffer_free(&msg);
}
/* ssh1 only */
static void
process_authentication_challenge1(SocketEntry *e)
{
Key *key, *private;
BIGNUM *challenge;
int i, len;
Buffer msg;
MD5_CTX md;
u_char buf[32], mdbuf[16], session_id[16];
u_int response_type;
buffer_init(&msg);
key = key_new(KEY_RSA1);
challenge = BN_new();
buffer_get_int(&e->input); /* ignored */
buffer_get_bignum(&e->input, key->rsa->e);
buffer_get_bignum(&e->input, key->rsa->n);
buffer_get_bignum(&e->input, challenge);
/* Only protocol 1.1 is supported */
if (buffer_len(&e->input) == 0)
goto failure;
buffer_get(&e->input, (char *) session_id, 16);
response_type = buffer_get_int(&e->input);
if (response_type != 1)
goto failure;
private = lookup_private_key(key, NULL, 1);
if (private != NULL) {
/* Decrypt the challenge using the private key. */
if (rsa_private_decrypt(challenge, challenge, private->rsa) <= 0)
goto failure;
/* The response is MD5 of decrypted challenge plus session id. */
len = BN_num_bytes(challenge);
if (len <= 0 || len > 32) {
log("process_authentication_challenge: bad challenge length %d", len);
goto failure;
}
memset(buf, 0, 32);
BN_bn2bin(challenge, buf + 32 - len);
MD5_Init(&md);
MD5_Update(&md, buf, 32);
MD5_Update(&md, session_id, 16);
MD5_Final(mdbuf, &md);
/* Send the response. */
buffer_put_char(&msg, SSH_AGENT_RSA_RESPONSE);
for (i = 0; i < 16; i++)
buffer_put_char(&msg, mdbuf[i]);
goto send;
}
failure:
/* Unknown identity or protocol error. Send failure. */
buffer_put_char(&msg, SSH_AGENT_FAILURE);
send:
buffer_put_int(&e->output, buffer_len(&msg));
buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg));
key_free(key);
BN_clear_free(challenge);
buffer_free(&msg);
}
/* ssh2 only */
static void
process_sign_request2(SocketEntry *e)
{
extern int datafellows;
Key *key, *private;
u_char *blob, *data, *signature = NULL;
u_int blen, dlen, slen = 0;
int flags;
Buffer msg;
int ok = -1;
datafellows = 0;
blob = buffer_get_string(&e->input, &blen);
data = buffer_get_string(&e->input, &dlen);
flags = buffer_get_int(&e->input);
if (flags & SSH_AGENT_OLD_SIGNATURE)
datafellows = SSH_BUG_SIGBLOB;
key = key_from_blob(blob, blen);
if (key != NULL) {
private = lookup_private_key(key, NULL, 2);
if (private != NULL)
ok = key_sign(private, &signature, &slen, data, dlen);
}
key_free(key);
buffer_init(&msg);
if (ok == 0) {
buffer_put_char(&msg, SSH2_AGENT_SIGN_RESPONSE);
buffer_put_string(&msg, signature, slen);
} else {
buffer_put_char(&msg, SSH_AGENT_FAILURE);
}
buffer_put_int(&e->output, buffer_len(&msg));
buffer_append(&e->output, buffer_ptr(&msg),
buffer_len(&msg));
buffer_free(&msg);
xfree(data);
xfree(blob);
if (signature != NULL)
xfree(signature);
}
/* shared */
static void
process_remove_identity(SocketEntry *e, int version)
{
Key *key = NULL, *private;
u_char *blob;
u_int blen;
u_int bits;
int success = 0;
switch (version) {
case 1:
key = key_new(KEY_RSA1);
bits = buffer_get_int(&e->input);
buffer_get_bignum(&e->input, key->rsa->e);
buffer_get_bignum(&e->input, key->rsa->n);
if (bits != key_size(key))
log("Warning: identity keysize mismatch: actual %d, announced %d",
key_size(key), bits);
break;
case 2:
blob = buffer_get_string(&e->input, &blen);
key = key_from_blob(blob, blen);
xfree(blob);
break;
}
if (key != NULL) {
int idx;
private = lookup_private_key(key, &idx, version);
if (private != NULL) {
/*
* We have this key. Free the old key. Since we
* don\'t want to leave empty slots in the middle of
* the array, we actually free the key there and move
* all the entries between the empty slot and the end
* of the array.
*/
Idtab *tab = idtab_lookup(version);
key_free(tab->identities[idx].key);
xfree(tab->identities[idx].comment);
if (tab->nentries < 1)
fatal("process_remove_identity: "
"internal error: tab->nentries %d",
tab->nentries);
if (idx != tab->nentries - 1) {
int i;
for (i = idx; i < tab->nentries - 1; i++)
tab->identities[i] = tab->identities[i+1];
}
tab->identities[tab->nentries - 1].key = NULL;
tab->identities[tab->nentries - 1].comment = NULL;
tab->nentries--;
success = 1;
}
key_free(key);
}
buffer_put_int(&e->output, 1);
buffer_put_char(&e->output,
success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
}
static void
process_remove_all_identities(SocketEntry *e, int version)
{
u_int i;
Idtab *tab = idtab_lookup(version);
/* Loop over all identities and clear the keys. */
for (i = 0; i < tab->nentries; i++) {
key_free(tab->identities[i].key);
xfree(tab->identities[i].comment);
}
/* Mark that there are no identities. */
tab->nentries = 0;
/* Send success. */
buffer_put_int(&e->output, 1);
buffer_put_char(&e->output, SSH_AGENT_SUCCESS);
return;
}
static void
process_add_identity(SocketEntry *e, int version)
{
Key *k = NULL;
char *type_name;
char *comment;
int type, success = 0;
Idtab *tab = idtab_lookup(version);
switch (version) {
case 1:
k = key_new_private(KEY_RSA1);
buffer_get_int(&e->input); /* ignored */
buffer_get_bignum(&e->input, k->rsa->n);
buffer_get_bignum(&e->input, k->rsa->e);
buffer_get_bignum(&e->input, k->rsa->d);
buffer_get_bignum(&e->input, k->rsa->iqmp);
/* SSH and SSL have p and q swapped */
buffer_get_bignum(&e->input, k->rsa->q); /* p */
buffer_get_bignum(&e->input, k->rsa->p); /* q */
/* Generate additional parameters */
rsa_generate_additional_parameters(k->rsa);
break;
case 2:
type_name = buffer_get_string(&e->input, NULL);
type = key_type_from_name(type_name);
xfree(type_name);
switch (type) {
case KEY_DSA:
k = key_new_private(type);
buffer_get_bignum2(&e->input, k->dsa->p);
buffer_get_bignum2(&e->input, k->dsa->q);
buffer_get_bignum2(&e->input, k->dsa->g);
buffer_get_bignum2(&e->input, k->dsa->pub_key);
buffer_get_bignum2(&e->input, k->dsa->priv_key);
break;
case KEY_RSA:
k = key_new_private(type);
buffer_get_bignum2(&e->input, k->rsa->n);
buffer_get_bignum2(&e->input, k->rsa->e);
buffer_get_bignum2(&e->input, k->rsa->d);
buffer_get_bignum2(&e->input, k->rsa->iqmp);
buffer_get_bignum2(&e->input, k->rsa->p);
buffer_get_bignum2(&e->input, k->rsa->q);
/* Generate additional parameters */
rsa_generate_additional_parameters(k->rsa);
break;
default:
buffer_clear(&e->input);
goto send;
}
break;
}
comment = buffer_get_string(&e->input, NULL);
if (k == NULL) {
xfree(comment);
goto send;
}
success = 1;
if (lookup_private_key(k, NULL, version) == NULL) {
if (tab->nentries == 0)
tab->identities = xmalloc(sizeof(Identity));
else
tab->identities = xrealloc(tab->identities,
(tab->nentries + 1) * sizeof(Identity));
tab->identities[tab->nentries].key = k;
tab->identities[tab->nentries].comment = comment;
/* Increment the number of identities. */
tab->nentries++;
} else {
key_free(k);
xfree(comment);
}
send:
buffer_put_int(&e->output, 1);
buffer_put_char(&e->output,
success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
}
#ifdef SMARTCARD
static void
process_add_smartcard_key (SocketEntry *e)
{
Idtab *tab;
Key *n = NULL, *k = NULL;
char *sc_reader_id = NULL;
int success = 0;
sc_reader_id = buffer_get_string(&e->input, NULL);
k = sc_get_key(sc_reader_id);
xfree(sc_reader_id);
if (k == NULL) {
error("sc_get_pubkey failed");
goto send;
}
success = 1;
tab = idtab_lookup(1);
k->type = KEY_RSA1;
if (lookup_private_key(k, NULL, 1) == NULL) {
if (tab->nentries == 0)
tab->identities = xmalloc(sizeof(Identity));
else
tab->identities = xrealloc(tab->identities,
(tab->nentries + 1) * sizeof(Identity));
n = key_new(KEY_RSA1);
BN_copy(n->rsa->n, k->rsa->n);
BN_copy(n->rsa->e, k->rsa->e);
RSA_set_method(n->rsa, sc_get_engine());
tab->identities[tab->nentries].key = n;
tab->identities[tab->nentries].comment =
xstrdup("rsa1 smartcard");
tab->nentries++;
}
k->type = KEY_RSA;
tab = idtab_lookup(2);
if (lookup_private_key(k, NULL, 2) == NULL) {
if (tab->nentries == 0)
tab->identities = xmalloc(sizeof(Identity));
else
tab->identities = xrealloc(tab->identities,
(tab->nentries + 1) * sizeof(Identity));
n = key_new(KEY_RSA);
BN_copy(n->rsa->n, k->rsa->n);
BN_copy(n->rsa->e, k->rsa->e);
RSA_set_method(n->rsa, sc_get_engine());
tab->identities[tab->nentries].key = n;
tab->identities[tab->nentries].comment =
xstrdup("rsa smartcard");
tab->nentries++;
}
key_free(k);
send:
buffer_put_int(&e->output, 1);
buffer_put_char(&e->output,
success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
}
static void
process_remove_smartcard_key(SocketEntry *e)
{
Key *k = NULL, *private;
int idx;
int success = 0;
char *sc_reader_id = NULL;
sc_reader_id = buffer_get_string(&e->input, NULL);
k = sc_get_key(sc_reader_id);
xfree(sc_reader_id);
if (k == NULL) {
error("sc_get_pubkey failed");
} else {
k->type = KEY_RSA1;
private = lookup_private_key(k, &idx, 1);
if (private != NULL) {
Idtab *tab = idtab_lookup(1);
key_free(tab->identities[idx].key);
xfree(tab->identities[idx].comment);
if (idx != tab->nentries)
tab->identities[idx] = tab->identities[tab->nentries];
tab->nentries--;
success = 1;
}
k->type = KEY_RSA;
private = lookup_private_key(k, &idx, 2);
if (private != NULL) {
Idtab *tab = idtab_lookup(2);
key_free(tab->identities[idx].key);
xfree(tab->identities[idx].comment);
if (idx != tab->nentries)
tab->identities[idx] = tab->identities[tab->nentries];
tab->nentries--;
success = 1;
}
key_free(k);
}
buffer_put_int(&e->output, 1);
buffer_put_char(&e->output,
success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
}
#endif /* SMARTCARD */
/* dispatch incoming messages */
static void
process_message(SocketEntry *e)
{
u_int msg_len;
u_int type;
u_char *cp;
if (buffer_len(&e->input) < 5)
return; /* Incomplete message. */
cp = (u_char *) buffer_ptr(&e->input);
msg_len = GET_32BIT(cp);
if (msg_len > 256 * 1024) {
shutdown(e->fd, SHUT_RDWR);
close(e->fd);
e->type = AUTH_UNUSED;
return;
}
if (buffer_len(&e->input) < msg_len + 4)
return;
buffer_consume(&e->input, 4);
type = buffer_get_char(&e->input);
debug("type %d", type);
switch (type) {
/* ssh1 */
case SSH_AGENTC_RSA_CHALLENGE:
process_authentication_challenge1(e);
break;
case SSH_AGENTC_REQUEST_RSA_IDENTITIES:
process_request_identities(e, 1);
break;
case SSH_AGENTC_ADD_RSA_IDENTITY:
process_add_identity(e, 1);
break;
case SSH_AGENTC_REMOVE_RSA_IDENTITY:
process_remove_identity(e, 1);
break;
case SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES:
process_remove_all_identities(e, 1);
break;
/* ssh2 */
case SSH2_AGENTC_SIGN_REQUEST:
process_sign_request2(e);
break;
case SSH2_AGENTC_REQUEST_IDENTITIES:
process_request_identities(e, 2);
break;
case SSH2_AGENTC_ADD_IDENTITY:
process_add_identity(e, 2);
break;
case SSH2_AGENTC_REMOVE_IDENTITY:
process_remove_identity(e, 2);
break;
case SSH2_AGENTC_REMOVE_ALL_IDENTITIES:
process_remove_all_identities(e, 2);
break;
#ifdef SMARTCARD
case SSH_AGENTC_ADD_SMARTCARD_KEY:
process_add_smartcard_key(e);
break;
case SSH_AGENTC_REMOVE_SMARTCARD_KEY:
process_remove_smartcard_key(e);
break;
#endif /* SMARTCARD */
default:
/* Unknown message. Respond with failure. */
error("Unknown message %d", type);
buffer_clear(&e->input);
buffer_put_int(&e->output, 1);
buffer_put_char(&e->output, SSH_AGENT_FAILURE);
break;
}
}
static void
new_socket(sock_type type, int fd)
{
u_int i, old_alloc;
if (fcntl(fd, F_SETFL, O_NONBLOCK) < 0)
error("fcntl O_NONBLOCK: %s", strerror(errno));
if (fd > max_fd)
max_fd = fd;
for (i = 0; i < sockets_alloc; i++)
if (sockets[i].type == AUTH_UNUSED) {
sockets[i].fd = fd;
sockets[i].type = type;
buffer_init(&sockets[i].input);
buffer_init(&sockets[i].output);
return;
}
old_alloc = sockets_alloc;
sockets_alloc += 10;
if (sockets)
sockets = xrealloc(sockets, sockets_alloc * sizeof(sockets[0]));
else
sockets = xmalloc(sockets_alloc * sizeof(sockets[0]));
for (i = old_alloc; i < sockets_alloc; i++)
sockets[i].type = AUTH_UNUSED;
sockets[old_alloc].type = type;
sockets[old_alloc].fd = fd;
buffer_init(&sockets[old_alloc].input);
buffer_init(&sockets[old_alloc].output);
}
static int
prepare_select(fd_set **fdrp, fd_set **fdwp, int *fdl, int *nallocp)
{
u_int i, sz;
int n = 0;
for (i = 0; i < sockets_alloc; i++) {
switch (sockets[i].type) {
case AUTH_SOCKET:
case AUTH_CONNECTION:
n = MAX(n, sockets[i].fd);
break;
case AUTH_UNUSED:
break;
default:
fatal("Unknown socket type %d", sockets[i].type);
break;
}
}
sz = howmany(n+1, NFDBITS) * sizeof(fd_mask);
if (*fdrp == NULL || sz > *nallocp) {
if (*fdrp)
xfree(*fdrp);
if (*fdwp)
xfree(*fdwp);
*fdrp = xmalloc(sz);
*fdwp = xmalloc(sz);
*nallocp = sz;
}
if (n < *fdl)
debug("XXX shrink: %d < %d", n, *fdl);
*fdl = n;
memset(*fdrp, 0, sz);
memset(*fdwp, 0, sz);
for (i = 0; i < sockets_alloc; i++) {
switch (sockets[i].type) {
case AUTH_SOCKET:
case AUTH_CONNECTION:
FD_SET(sockets[i].fd, *fdrp);
if (buffer_len(&sockets[i].output) > 0)
FD_SET(sockets[i].fd, *fdwp);
break;
default:
break;
}
}
return (1);
}
static void
after_select(fd_set *readset, fd_set *writeset)
{
u_int i;
int len, sock;
socklen_t slen;
char buf[1024];
struct sockaddr_un sunaddr;
for (i = 0; i < sockets_alloc; i++)
switch (sockets[i].type) {
case AUTH_UNUSED:
break;
case AUTH_SOCKET:
if (FD_ISSET(sockets[i].fd, readset)) {
slen = sizeof(sunaddr);
sock = accept(sockets[i].fd,
(struct sockaddr *) &sunaddr, &slen);
if (sock < 0) {
perror("accept from AUTH_SOCKET");
break;
}
new_socket(AUTH_CONNECTION, sock);
}
break;
case AUTH_CONNECTION:
if (buffer_len(&sockets[i].output) > 0 &&
FD_ISSET(sockets[i].fd, writeset)) {
do {
len = write(sockets[i].fd,
buffer_ptr(&sockets[i].output),
buffer_len(&sockets[i].output));
if (len == -1 && (errno == EAGAIN ||
errno == EINTR))
continue;
break;
} while (1);
if (len <= 0) {
shutdown(sockets[i].fd, SHUT_RDWR);
close(sockets[i].fd);
sockets[i].type = AUTH_UNUSED;
buffer_free(&sockets[i].input);
buffer_free(&sockets[i].output);
break;
}
buffer_consume(&sockets[i].output, len);
}
if (FD_ISSET(sockets[i].fd, readset)) {
do {
len = read(sockets[i].fd, buf, sizeof(buf));
if (len == -1 && (errno == EAGAIN ||
errno == EINTR))
continue;
break;
} while (1);
if (len <= 0) {
shutdown(sockets[i].fd, SHUT_RDWR);
close(sockets[i].fd);
sockets[i].type = AUTH_UNUSED;
buffer_free(&sockets[i].input);
buffer_free(&sockets[i].output);
break;
}
buffer_append(&sockets[i].input, buf, len);
process_message(&sockets[i]);
}
break;
default:
fatal("Unknown type %d", sockets[i].type);
}
}
static void
cleanup_socket(void)
{
if (socket_name[0])
unlink(socket_name);
if (socket_dir[0])
rmdir(socket_dir);
}
static void
cleanup_exit(int i)
{
cleanup_socket();
exit(i);
}
static void
cleanup_handler(int sig)
{
cleanup_socket();
_exit(2);
}
static void
check_parent_exists(int sig)
{
int save_errno = errno;
if (parent_pid != -1 && kill(parent_pid, 0) < 0) {
/* printf("Parent has died - Authentication agent exiting.\n"); */
cleanup_handler(sig); /* safe */
}
signal(SIGALRM, check_parent_exists);
alarm(10);
errno = save_errno;
}
static void
usage(void)
{
fprintf(stderr, "Usage: %s [options] [command [args ...]]\n",
__progname);
fprintf(stderr, "Options:\n");
fprintf(stderr, " -c Generate C-shell commands on stdout.\n");
fprintf(stderr, " -s Generate Bourne shell commands on stdout.\n");
fprintf(stderr, " -k Kill the current agent.\n");
fprintf(stderr, " -d Debug mode.\n");
exit(1);
}
int
main(int ac, char **av)
{
int sock, c_flag = 0, d_flag = 0, k_flag = 0, s_flag = 0, ch, nalloc;
struct sockaddr_un sunaddr;
struct rlimit rlim;
pid_t pid;
char *shell, *format, *pidstr, pidstrbuf[1 + 3 * sizeof pid];
extern int optind;
fd_set *readsetp = NULL, *writesetp = NULL;
SSLeay_add_all_algorithms();
while ((ch = getopt(ac, av, "cdks")) != -1) {
switch (ch) {
case 'c':
if (s_flag)
usage();
c_flag++;
break;
case 'k':
k_flag++;
break;
case 's':
if (c_flag)
usage();
s_flag++;
break;
case 'd':
if (d_flag)
usage();
d_flag++;
break;
default:
usage();
}
}
ac -= optind;
av += optind;
if (ac > 0 && (c_flag || k_flag || s_flag || d_flag))
usage();
if (ac == 0 && !c_flag && !k_flag && !s_flag && !d_flag) {
shell = getenv("SHELL");
if (shell != NULL && strncmp(shell + strlen(shell) - 3, "csh", 3) == 0)
c_flag = 1;
}
if (k_flag) {
pidstr = getenv(SSH_AGENTPID_ENV_NAME);
if (pidstr == NULL) {
fprintf(stderr, "%s not set, cannot kill agent\n",
SSH_AGENTPID_ENV_NAME);
exit(1);
}
pid = atoi(pidstr);
if (pid < 1) {
fprintf(stderr, "%s=\"%s\", which is not a good PID\n",
SSH_AGENTPID_ENV_NAME, pidstr);
exit(1);
}
if (kill(pid, SIGTERM) == -1) {
perror("kill");
exit(1);
}
format = c_flag ? "unsetenv %s;\n" : "unset %s;\n";
printf(format, SSH_AUTHSOCKET_ENV_NAME);
printf(format, SSH_AGENTPID_ENV_NAME);
printf("echo Agent pid %d killed;\n", pid);
exit(0);
}
parent_pid = getpid();
/* Create private directory for agent socket */
strlcpy(socket_dir, "/tmp/ssh-XXXXXXXX", sizeof socket_dir);
if (mkdtemp(socket_dir) == NULL) {
perror("mkdtemp: private socket dir");
exit(1);
}
snprintf(socket_name, sizeof socket_name, "%s/agent.%d", socket_dir,
parent_pid);
/*
* Create socket early so it will exist before command gets run from
* the parent.
*/
sock = socket(AF_UNIX, SOCK_STREAM, 0);
if (sock < 0) {
perror("socket");
cleanup_exit(1);
}
memset(&sunaddr, 0, sizeof(sunaddr));
sunaddr.sun_family = AF_UNIX;
strlcpy(sunaddr.sun_path, socket_name, sizeof(sunaddr.sun_path));
if (bind(sock, (struct sockaddr *) & sunaddr, sizeof(sunaddr)) < 0) {
perror("bind");
cleanup_exit(1);
}
if (listen(sock, 5) < 0) {
perror("listen");
cleanup_exit(1);
}
/*
* Fork, and have the parent execute the command, if any, or present
* the socket data. The child continues as the authentication agent.
*/
if (d_flag) {
log_init(__progname, SYSLOG_LEVEL_DEBUG1, SYSLOG_FACILITY_AUTH, 1);
format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n";
printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name,
SSH_AUTHSOCKET_ENV_NAME);
printf("echo Agent pid %d;\n", parent_pid);
goto skip;
}
pid = fork();
if (pid == -1) {
perror("fork");
exit(1);
}
if (pid != 0) { /* Parent - execute the given command. */
close(sock);
snprintf(pidstrbuf, sizeof pidstrbuf, "%d", pid);
if (ac == 0) {
format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n";
printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name,
SSH_AUTHSOCKET_ENV_NAME);
printf(format, SSH_AGENTPID_ENV_NAME, pidstrbuf,
SSH_AGENTPID_ENV_NAME);
printf("echo Agent pid %d;\n", pid);
exit(0);
}
if (setenv(SSH_AUTHSOCKET_ENV_NAME, socket_name, 1) == -1 ||
setenv(SSH_AGENTPID_ENV_NAME, pidstrbuf, 1) == -1) {
perror("setenv");
exit(1);
}
execvp(av[0], av);
perror(av[0]);
exit(1);
}
if (setsid() == -1) {
perror("setsid");
cleanup_exit(1);
}
(void)chdir("/");
close(0);
close(1);
close(2);
/* deny core dumps, since memory contains unencrypted private keys */
rlim.rlim_cur = rlim.rlim_max = 0;
if (setrlimit(RLIMIT_CORE, &rlim) < 0) {
perror("setrlimit rlimit_core failed");
cleanup_exit(1);
}
skip:
if (atexit(cleanup_socket) < 0) {
perror("atexit");
cleanup_exit(1);
}
new_socket(AUTH_SOCKET, sock);
if (ac > 0) {
signal(SIGALRM, check_parent_exists);
alarm(10);
}
idtab_init();
if (!d_flag)
signal(SIGINT, SIG_IGN);
signal(SIGPIPE, SIG_IGN);
signal(SIGHUP, cleanup_handler);
signal(SIGTERM, cleanup_handler);
nalloc = 0;
while (1) {
prepare_select(&readsetp, &writesetp, &max_fd, &nalloc);
if (select(max_fd + 1, readsetp, writesetp, NULL, NULL) < 0) {
if (errno == EINTR)
continue;
exit(1);
}
after_select(readsetp, writesetp);
}
/* NOTREACHED */
}
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