+/* $OpenBSD: ssh-agent.c,v 1.152 2006/08/04 20:46:05 stevesk Exp $ */
/*
* Author: Tatu Ylonen <ylo@cs.hut.fi>
* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
*/
#include "includes.h"
-#include "openbsd-compat/fake-queue.h"
-RCSID("$OpenBSD: ssh-agent.c,v 1.101 2002/08/22 19:27:53 stevesk Exp $");
+
+#include <sys/types.h>
+#include <sys/param.h>
+#include <sys/resource.h>
+#include <sys/stat.h>
+#include <sys/socket.h>
+#ifdef HAVE_SYS_TIME_H
+# include <sys/time.h>
+#endif
+#ifdef HAVE_SYS_UN_H
+# include <sys/un.h>
+#endif
+#include "openbsd-compat/sys-queue.h"
#include <openssl/evp.h>
#include <openssl/md5.h>
+#include <errno.h>
+#include <fcntl.h>
+#ifdef HAVE_PATHS_H
+# include <paths.h>
+#endif
+#include <signal.h>
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "xmalloc.h"
#include "ssh.h"
#include "rsa.h"
#include "buffer.h"
-#include "bufaux.h"
-#include "xmalloc.h"
-#include "getput.h"
#include "key.h"
#include "authfd.h"
#include "compat.h"
#include "log.h"
+#include "misc.h"
#ifdef SMARTCARD
#include "scard.h"
#endif
+#if defined(HAVE_SYS_PRCTL_H)
+#include <sys/prctl.h> /* For prctl() and PR_SET_DUMPABLE */
+#endif
+
typedef enum {
AUTH_UNUSED,
AUTH_SOCKET,
Key *key;
char *comment;
u_int death;
+ u_int confirm;
} Identity;
typedef struct {
pid_t parent_pid = -1;
/* pathname and directory for AUTH_SOCKET */
-char socket_name[1024];
-char socket_dir[1024];
+char socket_name[MAXPATHLEN];
+char socket_dir[MAXPATHLEN];
/* locking */
int locked = 0;
char *lock_passwd = NULL;
-#ifdef HAVE___PROGNAME
extern char *__progname;
-#else
-char *__progname;
-#endif
+
+/* Default lifetime (0 == forever) */
+static int lifetime = 0;
static void
close_socket(SocketEntry *e)
{
- shutdown(e->fd, SHUT_RDWR);
close(e->fd);
e->fd = -1;
e->type = AUTH_UNUSED;
return (NULL);
}
+/* Check confirmation of keysign request */
+static int
+confirm_key(Identity *id)
+{
+ char *p;
+ int ret = -1;
+
+ p = key_fingerprint(id->key, SSH_FP_MD5, SSH_FP_HEX);
+ if (ask_permission("Allow use of key %s?\nKey fingerprint %s.",
+ id->comment, p))
+ ret = 0;
+ xfree(p);
+
+ return (ret);
+}
+
/* send list of supported public keys to 'client' */
static void
process_request_identities(SocketEntry *e, int version)
goto failure;
id = lookup_identity(key, 1);
- if (id != NULL) {
+ if (id != NULL && (!id->confirm || confirm_key(id) == 0)) {
Key *private = id->key;
/* Decrypt the challenge using the private key. */
if (rsa_private_decrypt(challenge, challenge, private->rsa) <= 0)
/* 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);
+ logit("process_authentication_challenge: bad challenge length %d", len);
goto failure;
}
memset(buf, 0, 32);
key = key_from_blob(blob, blen);
if (key != NULL) {
Identity *id = lookup_identity(key, 2);
- if (id != NULL)
+ if (id != NULL && (!id->confirm || confirm_key(id) == 0))
ok = key_sign(id->key, &signature, &slen, data, dlen);
+ key_free(key);
}
- key_free(key);
buffer_init(&msg);
if (ok == 0) {
buffer_put_char(&msg, SSH2_AGENT_SIGN_RESPONSE);
buffer_get_bignum(&e->request, key->rsa->n);
if (bits != key_size(key))
- log("Warning: identity keysize mismatch: actual %u, announced %u",
+ logit("Warning: identity keysize mismatch: actual %u, announced %u",
key_size(key), bits);
break;
case 2:
if (id != NULL) {
/*
* We have this key. Free the old key. Since we
- * don\'t want to leave empty slots in the middle of
+ * 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.
process_add_identity(SocketEntry *e, int version)
{
Idtab *tab = idtab_lookup(version);
- int type, success = 0, death = 0;
+ int type, success = 0, death = 0, confirm = 0;
char *type_name, *comment;
Key *k = NULL;
}
break;
}
+ /* enable blinding */
+ switch (k->type) {
+ case KEY_RSA:
+ case KEY_RSA1:
+ if (RSA_blinding_on(k->rsa, NULL) != 1) {
+ error("process_add_identity: RSA_blinding_on failed");
+ key_free(k);
+ goto send;
+ }
+ break;
+ }
comment = buffer_get_string(&e->request, NULL);
if (k == NULL) {
xfree(comment);
case SSH_AGENT_CONSTRAIN_LIFETIME:
death = time(NULL) + buffer_get_int(&e->request);
break;
+ case SSH_AGENT_CONSTRAIN_CONFIRM:
+ confirm = 1;
+ break;
default:
break;
}
}
+ if (lifetime && !death)
+ death = time(NULL) + lifetime;
if (lookup_identity(k, version) == NULL) {
Identity *id = xmalloc(sizeof(Identity));
id->key = k;
id->comment = comment;
id->death = death;
+ id->confirm = confirm;
TAILQ_INSERT_TAIL(&tab->idlist, id, next);
/* Increment the number of identities. */
tab->nentries++;
process_add_smartcard_key (SocketEntry *e)
{
char *sc_reader_id = NULL, *pin;
- int i, version, success = 0;
+ int i, version, success = 0, death = 0, confirm = 0;
Key **keys, *k;
Identity *id;
Idtab *tab;
sc_reader_id = buffer_get_string(&e->request, NULL);
pin = buffer_get_string(&e->request, NULL);
+
+ while (buffer_len(&e->request)) {
+ switch (buffer_get_char(&e->request)) {
+ case SSH_AGENT_CONSTRAIN_LIFETIME:
+ death = time(NULL) + buffer_get_int(&e->request);
+ break;
+ case SSH_AGENT_CONSTRAIN_CONFIRM:
+ confirm = 1;
+ break;
+ default:
+ break;
+ }
+ }
+ if (lifetime && !death)
+ death = time(NULL) + lifetime;
+
keys = sc_get_keys(sc_reader_id, pin);
xfree(sc_reader_id);
xfree(pin);
if (lookup_identity(k, version) == NULL) {
id = xmalloc(sizeof(Identity));
id->key = k;
- id->comment = xstrdup("smartcard key");
- id->death = 0;
+ id->comment = sc_get_key_label(k);
+ id->death = death;
+ id->confirm = confirm;
TAILQ_INSERT_TAIL(&tab->idlist, id, next);
tab->nentries++;
success = 1;
if (buffer_len(&e->input) < 5)
return; /* Incomplete message. */
cp = buffer_ptr(&e->input);
- msg_len = GET_32BIT(cp);
+ msg_len = get_u32(cp);
if (msg_len > 256 * 1024) {
close_socket(e);
return;
break;
#ifdef SMARTCARD
case SSH_AGENTC_ADD_SMARTCARD_KEY:
+ case SSH_AGENTC_ADD_SMARTCARD_KEY_CONSTRAINED:
process_add_smartcard_key(e);
break;
case SSH_AGENTC_REMOVE_SMARTCARD_KEY:
static void
new_socket(sock_type type, int fd)
{
- u_int i, old_alloc;
+ u_int i, old_alloc, new_alloc;
- if (fcntl(fd, F_SETFL, O_NONBLOCK) < 0)
- error("fcntl O_NONBLOCK: %s", strerror(errno));
+ set_nonblock(fd);
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);
buffer_init(&sockets[i].request);
+ sockets[i].type = type;
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++)
+ new_alloc = sockets_alloc + 10;
+ sockets = xrealloc(sockets, new_alloc, sizeof(sockets[0]));
+ for (i = old_alloc; i < new_alloc; i++)
sockets[i].type = AUTH_UNUSED;
- sockets[old_alloc].type = type;
+ sockets_alloc = new_alloc;
sockets[old_alloc].fd = fd;
buffer_init(&sockets[old_alloc].input);
buffer_init(&sockets[old_alloc].output);
buffer_init(&sockets[old_alloc].request);
+ sockets[old_alloc].type = type;
}
static int
-prepare_select(fd_set **fdrp, fd_set **fdwp, int *fdl, int *nallocp)
+prepare_select(fd_set **fdrp, fd_set **fdwp, int *fdl, u_int *nallocp)
{
u_int i, sz;
int n = 0;
char buf[1024];
int len, sock;
u_int i;
+ uid_t euid;
+ gid_t egid;
for (i = 0; i < sockets_alloc; i++)
switch (sockets[i].type) {
if (FD_ISSET(sockets[i].fd, readset)) {
slen = sizeof(sunaddr);
sock = accept(sockets[i].fd,
- (struct sockaddr *) &sunaddr, &slen);
+ (struct sockaddr *)&sunaddr, &slen);
if (sock < 0) {
error("accept from AUTH_SOCKET: %s",
strerror(errno));
break;
}
+ if (getpeereid(sock, &euid, &egid) < 0) {
+ error("getpeereid %d failed: %s",
+ sock, strerror(errno));
+ close(sock);
+ break;
+ }
+ if ((euid != 0) && (getuid() != euid)) {
+ error("uid mismatch: "
+ "peer euid %u != uid %u",
+ (u_int) euid, (u_int) getuid());
+ close(sock);
+ break;
+ }
new_socket(AUTH_CONNECTION, sock);
}
break;
}
static void
-cleanup_socket(void *p)
+cleanup_socket(void)
{
if (socket_name[0])
unlink(socket_name);
rmdir(socket_dir);
}
-static void
+void
cleanup_exit(int i)
{
- cleanup_socket(NULL);
- exit(i);
+ cleanup_socket();
+ _exit(i);
}
+/*ARGSUSED*/
static void
cleanup_handler(int sig)
{
- cleanup_socket(NULL);
+ cleanup_socket();
_exit(2);
}
+/*ARGSUSED*/
static void
check_parent_exists(int sig)
{
/* printf("Parent has died - Authentication agent exiting.\n"); */
cleanup_handler(sig); /* safe */
}
- signal(SIGALRM, check_parent_exists);
+ mysignal(SIGALRM, check_parent_exists);
alarm(10);
errno = save_errno;
}
fprintf(stderr, " -k Kill the current agent.\n");
fprintf(stderr, " -d Debug mode.\n");
fprintf(stderr, " -a socket Bind agent socket to given name.\n");
+ fprintf(stderr, " -t life Default identity lifetime (seconds).\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;
+ int c_flag = 0, d_flag = 0, k_flag = 0, s_flag = 0;
+ int sock, fd, ch;
+ u_int nalloc;
char *shell, *format, *pidstr, *agentsocket = NULL;
fd_set *readsetp = NULL, *writesetp = NULL;
struct sockaddr_un sunaddr;
#ifdef HAVE_SETRLIMIT
struct rlimit rlim;
#endif
-#ifdef HAVE_CYGWIN
int prev_mask;
-#endif
extern int optind;
extern char *optarg;
pid_t pid;
char pidstrbuf[1 + 3 * sizeof pid];
+ /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
+ sanitise_stdfd();
+
/* drop */
setegid(getgid());
setgid(getgid());
+#if defined(HAVE_PRCTL) && defined(PR_SET_DUMPABLE)
+ /* Disable ptrace on Linux without sgid bit */
+ prctl(PR_SET_DUMPABLE, 0);
+#endif
+
SSLeay_add_all_algorithms();
- __progname = get_progname(av[0]);
+ __progname = ssh_get_progname(av[0]);
init_rng();
seed_rng();
- while ((ch = getopt(ac, av, "cdksa:")) != -1) {
+ while ((ch = getopt(ac, av, "cdksa:t:")) != -1) {
switch (ch) {
case 'c':
if (s_flag)
case 'a':
agentsocket = optarg;
break;
+ case 't':
+ if ((lifetime = convtime(optarg)) == -1) {
+ fprintf(stderr, "Invalid lifetime\n");
+ usage();
+ }
+ break;
default:
usage();
}
if (ac == 0 && !c_flag && !s_flag) {
shell = getenv("SHELL");
- if (shell != NULL && strncmp(shell + strlen(shell) - 3, "csh", 3) == 0)
+ if (shell != NULL &&
+ strncmp(shell + strlen(shell) - 3, "csh", 3) == 0)
c_flag = 1;
}
if (k_flag) {
+ const char *errstr = NULL;
+
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);
+ pid = (int)strtonum(pidstr, 2, INT_MAX, &errstr);
+ if (errstr) {
+ fprintf(stderr,
+ "%s=\"%s\", which is not a good PID: %s\n",
+ SSH_AGENTPID_ENV_NAME, pidstr, errstr);
exit(1);
}
if (kill(pid, SIGTERM) == -1) {
if (agentsocket == NULL) {
/* Create private directory for agent socket */
- strlcpy(socket_dir, "/tmp/ssh-XXXXXXXX", sizeof socket_dir);
+ strlcpy(socket_dir, "/tmp/ssh-XXXXXXXXXX", sizeof socket_dir);
if (mkdtemp(socket_dir) == NULL) {
perror("mkdtemp: private socket dir");
exit(1);
sock = socket(AF_UNIX, SOCK_STREAM, 0);
if (sock < 0) {
perror("socket");
+ *socket_name = '\0'; /* Don't unlink any existing file */
cleanup_exit(1);
}
memset(&sunaddr, 0, sizeof(sunaddr));
sunaddr.sun_family = AF_UNIX;
strlcpy(sunaddr.sun_path, socket_name, sizeof(sunaddr.sun_path));
-#ifdef HAVE_CYGWIN
prev_mask = umask(0177);
-#endif
- if (bind(sock, (struct sockaddr *) & sunaddr, sizeof(sunaddr)) < 0) {
+ if (bind(sock, (struct sockaddr *) &sunaddr, sizeof(sunaddr)) < 0) {
perror("bind");
-#ifdef HAVE_CYGWIN
+ *socket_name = '\0'; /* Don't unlink any existing file */
umask(prev_mask);
-#endif
cleanup_exit(1);
}
-#ifdef HAVE_CYGWIN
umask(prev_mask);
-#endif
- if (listen(sock, 128) < 0) {
+ if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
perror("listen");
cleanup_exit(1);
}
}
(void)chdir("/");
- close(0);
- close(1);
- close(2);
+ if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) {
+ /* XXX might close listen socket */
+ (void)dup2(fd, STDIN_FILENO);
+ (void)dup2(fd, STDOUT_FILENO);
+ (void)dup2(fd, STDERR_FILENO);
+ if (fd > 2)
+ close(fd);
+ }
#ifdef HAVE_SETRLIMIT
/* deny core dumps, since memory contains unencrypted private keys */
#endif
skip:
- fatal_add_cleanup(cleanup_socket, NULL);
new_socket(AUTH_SOCKET, sock);
if (ac > 0) {
- signal(SIGALRM, check_parent_exists);
+ mysignal(SIGALRM, check_parent_exists);
alarm(10);
}
idtab_init();