-.\" $OpenBSD: ssh-keyscan.1,v 1.9 2001/08/02 18:37:35 mpech Exp $
+.\" $OpenBSD: ssh-keyscan.1,v 1.10 2001/08/05 23:18:20 markus Exp $
.\"
.\" Copyright 1995, 1996 by David Mazieres <dm@lcs.mit.edu>.
.\"
.Nd gather ssh public keys
.Sh SYNOPSIS
.Nm ssh-keyscan
-.Op Fl t Ar timeout
-.Op Ar -- | host | addrlist namelist
-.Op Fl f Ar files ...
+.Op Fl v46
+.Op Fl p Ar port
+.Op Fl T Ar timeout
+.Op Fl t Ar type
+.Op Fl f Ar file
+.Op Ar host | addrlist namelist
+.Op Ar ...
.Sh DESCRIPTION
.Nm
is a utility for gathering the public ssh host keys of a number of
.Pp
The options are as follows:
.Bl -tag -width Ds
-.It Fl t
+.It Fl p Ar port
+Port to connect to on the remote host.
+.It Fl T
Set the timeout for connection attempts. If
.Pa timeout
seconds have elapsed since a connection was initiated to a host or since the
last time anything was read from that host, then the connection is
closed and the host in question considered unavailable. Default is 5
seconds.
-.It Fl f
+.It Fl t Ar type
+Specifies the type of the key to fetch from the following hosts.
+The possible values are
+.Dq rsa1
+for protocol version 1 and
+.Dq rsa
+or
+.Dq dsa
+for protocol version 2.
+Multiple values may be specified by separating them with commas.
+The default is
+.Dq rsa1 .
+.It Fl f Ar filename
Read hosts or
.Pa addrlist namelist
pairs from this file, one per line.
will read hosts or
.Pa addrlist namelist
pairs from the standard input.
+.It Fl v
+Verbose mode.
+Causes
+.Nm
+to print debugging messages about its progress.
+.It Fl 4
+Forces
+.Nm
+to use IPv4 addresses only.
+.It Fl 6
+Forces
+.Nm
+to use IPv6 addresses only.
.El
.Sh SECURITY
If you make an ssh_known_hosts file using
can help you detect tampered keyfiles or man in the middle attacks which
have begun after you created your ssh_known_hosts file.
.Sh EXAMPLES
-Print the host key for machine
+.Pp
+Print the
+.Pa rsa1
+host key for machine
.Pa hostname :
.Bd -literal
ssh-keyscan hostname
which have new or different keys from those in the sorted file
.Pa ssh_known_hosts :
.Bd -literal
-$ ssh-keyscan -f ssh_hosts | sort -u - ssh_known_hosts | \e\
- diff ssh_known_hosts -
+ssh-keyscan -t rsa,dsa -f ssh_hosts | \e\
+ sort -u - ssh_known_hosts | diff ssh_known_hosts -
.Ed
.Sh FILES
.Pa Input format:
+.Bd -literal
1.2.3.4,1.2.4.4 name.my.domain,name,n.my.domain,n,1.2.3.4,1.2.4.4
+.Ed
.Pp
-.Pa Output format:
+.Pa Output format for rsa1 keys:
+.Bd -literal
host-or-namelist bits exponent modulus
+.Ed
+.Pp
+.Pa Output format for rsa and dsa keys:
+.Bd -literal
+host-or-namelist keytype base64-encoded-key
+.Ed
+.Pp
+Where
+.Pa keytype
+is either
+.Dq ssh-rsa
+or
+.Dq ssh-dsa .
.Pp
.Pa /etc/ssh_known_hosts
.Sh BUGS
It generates "Connection closed by remote host" messages on the consoles
-of all the machines it scans.
+of all the machines it scans if the server is older than version 2.9.
This is because it opens a connection to the ssh port, reads the public
key, and drops the connection as soon as it gets the key.
.Sh SEE ALSO
.Xr sshd 8
.Sh AUTHORS
David Mazieres <dm@lcs.mit.edu>
+wrote the initial version, and
+Wayne Davison <wayned@users.sourceforge.net>
+added support for protocol version 2.
*/
#include "includes.h"
-RCSID("$OpenBSD: ssh-keyscan.c,v 1.25 2001/08/03 10:31:30 jakob Exp $");
+RCSID("$OpenBSD: ssh-keyscan.c,v 1.26 2001/08/05 23:18:20 markus Exp $");
#if defined(HAVE_SYS_QUEUE_H) && !defined(HAVE_BOGUS_SYS_QUEUE_H)
#include <sys/queue.h>
#include <openssl/bn.h>
+#include <setjmp.h>
#include "xmalloc.h"
#include "ssh.h"
#include "ssh1.h"
#include "key.h"
+#include "kex.h"
+#include "compat.h"
+#include "myproposal.h"
+#include "packet.h"
+#include "dispatch.h"
#include "buffer.h"
#include "bufaux.h"
#include "log.h"
#include "atomicio.h"
+#include "misc.h"
-static int argno = 1; /* Number of argument currently being parsed */
+/* Flag indicating whether IPv4 or IPv6. This can be set on the command line.
+ Default value is AF_UNSPEC means both IPv4 and IPv6. */
+#ifdef IPV4_DEFAULT
+int IPv4or6 = AF_INET;
+#else
+int IPv4or6 = AF_UNSPEC;
+#endif
-int family = AF_UNSPEC; /* IPv4, IPv6 or both */
+int ssh_port = SSH_DEFAULT_PORT;
+
+#define KT_RSA1 1
+#define KT_DSA 2
+#define KT_RSA 4
+
+int get_keytypes = KT_RSA1; /* Get only RSA1 keys by default */
#define MAXMAXFD 256
fd_set *read_wait;
size_t read_wait_size;
int ncon;
+int nonfatal_fatal = 0;
+jmp_buf kexjmp;
/*
* Keep a connection structure for each file descriptor. The state
int c_plen; /* Packet length field for ssh packet */
int c_len; /* Total bytes which must be read. */
int c_off; /* Length of data read so far. */
+ int c_keytype; /* Only one of KT_RSA1, KT_DSA, or KT_RSA */
char *c_namebase; /* Address to free for c_name and c_namelist */
char *c_name; /* Hostname of connection for errors */
char *c_namelist; /* Pointer to other possible addresses */
char *c_output_name; /* Hostname of connection for output */
char *c_data; /* Data read from this fd */
+ Kex *c_kex; /* The key-exchange struct for ssh2 */
struct timeval c_tv; /* Time at which connection gets aborted */
TAILQ_ENTRY(Connection) c_link; /* List of connections in timeout order. */
} con;
return (tok);
}
-static void
-keyprint(char *host, char *output_name, char *kd, int len)
+static Key *
+keygrab_ssh1(con *c)
{
static Key *rsa;
static Buffer msg;
buffer_init(&msg);
rsa = key_new(KEY_RSA1);
}
- buffer_append(&msg, kd, len);
- buffer_consume(&msg, 8 - (len & 7)); /* padding */
+ buffer_append(&msg, c->c_data, c->c_plen);
+ buffer_consume(&msg, 8 - (c->c_plen & 7)); /* padding */
if (buffer_get_char(&msg) != (int) SSH_SMSG_PUBLIC_KEY) {
- error("%s: invalid packet type", host);
+ error("%s: invalid packet type", c->c_name);
buffer_clear(&msg);
- return;
+ return NULL;
}
buffer_consume(&msg, 8); /* cookie */
(void) buffer_get_int(&msg);
buffer_get_bignum(&msg, rsa->rsa->e);
buffer_get_bignum(&msg, rsa->rsa->n);
+
buffer_clear(&msg);
- fprintf(stdout, "%s ", output_name ? output_name : host);
- key_write(rsa, stdout);
+ return (rsa);
+}
+
+static int
+hostjump(Key *hostkey)
+{
+ longjmp(kexjmp, (int)hostkey);
+}
+
+static int
+ssh2_capable(int remote_major, int remote_minor)
+{
+ switch (remote_major) {
+ case 1:
+ if (remote_minor == 99)
+ return 1;
+ break;
+ case 2:
+ return 1;
+ default:
+ break;
+ }
+ return 0;
+}
+
+static Key *
+keygrab_ssh2(con *c)
+{
+ int j;
+
+ packet_set_connection(c->c_fd, c->c_fd);
+ enable_compat20();
+ myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = c->c_keytype == KT_DSA?
+ "ssh-dss": "ssh-rsa";
+ c->c_kex = kex_setup(myproposal);
+ c->c_kex->verify_host_key = hostjump;
+
+ if (!(j = setjmp(kexjmp))) {
+ nonfatal_fatal = 1;
+ dispatch_run(DISPATCH_BLOCK, &c->c_kex->done, c->c_kex);
+ fprintf(stderr, "Impossible! dispatch_run() returned!\n");
+ exit(1);
+ }
+ nonfatal_fatal = 0;
+ xfree(c->c_kex);
+ c->c_kex = NULL;
+ packet_close();
+ if (j < 0)
+ j = 0;
+
+ return (Key*)(j);
+}
+
+static void
+keyprint(con *c, Key *key)
+{
+ if (!key)
+ return;
+
+ fprintf(stdout, "%s ", c->c_output_name ? c->c_output_name : c->c_name);
+ key_write(key, stdout);
fputs("\n", stdout);
}
char strport[NI_MAXSERV];
int gaierr, s = -1;
- snprintf(strport, sizeof strport, "%d", SSH_DEFAULT_PORT);
+ snprintf(strport, sizeof strport, "%d", ssh_port);
memset(&hints, 0, sizeof(hints));
- hints.ai_family = family;
+ hints.ai_family = IPv4or6;
hints.ai_socktype = SOCK_STREAM;
if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0)
fatal("getaddrinfo %s: %s", host, gai_strerror(gaierr));
}
static int
-conalloc(char *iname, char *oname)
+conalloc(char *iname, char *oname, int keytype)
{
int s;
char *namebase, *name, *namelist;
fdcon[s].c_data = (char *) &fdcon[s].c_plen;
fdcon[s].c_len = 4;
fdcon[s].c_off = 0;
+ fdcon[s].c_keytype = keytype;
gettimeofday(&fdcon[s].c_tv, NULL);
fdcon[s].c_tv.tv_sec += timeout;
TAILQ_INSERT_TAIL(&tq, &fdcon[s], c_link);
if (fdcon[s].c_status == CS_KEYS)
xfree(fdcon[s].c_data);
fdcon[s].c_status = CS_UNUSED;
+ fdcon[s].c_keytype = 0;
TAILQ_REMOVE(&tq, &fdcon[s], c_link);
FD_CLR(s, read_wait);
ncon--;
{
int ret;
con *c = &fdcon[s];
- char *iname, *oname;
- iname = xstrdup(c->c_namelist);
- oname = xstrdup(c->c_output_name);
+ ret = conalloc(c->c_namelist, c->c_output_name, c->c_keytype);
confree(s);
- ret = conalloc(iname, oname);
- xfree(iname);
- xfree(oname);
return (ret);
}
static void
congreet(int s)
{
- char buf[80], *cp;
+ char buf[256], *cp;
size_t bufsiz;
int n = 0;
con *c = &fdcon[s];
}
*cp = '\0';
fprintf(stderr, "# %s %s\n", c->c_name, buf);
- n = snprintf(buf, sizeof buf, "SSH-1.5-OpenSSH-keyscan\r\n");
+ if (c->c_keytype != KT_RSA1) {
+ int remote_major, remote_minor;
+ char remote_version[sizeof buf];
+
+ if (sscanf(buf, "SSH-%d.%d-%[^\n]\n",
+ &remote_major, &remote_minor, remote_version) == 3)
+ compat_datafellows(remote_version);
+ else
+ datafellows = 0;
+ if (!ssh2_capable(remote_major, remote_minor)) {
+ debug("%s doesn't support ssh2", c->c_name);
+ confree(s);
+ return;
+ }
+ }
+ n = snprintf(buf, sizeof buf, "SSH-%d.%d-OpenSSH-keyscan\r\n",
+ c->c_keytype == KT_RSA1? PROTOCOL_MAJOR_1 : PROTOCOL_MAJOR_2,
+ c->c_keytype == KT_RSA1? PROTOCOL_MINOR_1 : PROTOCOL_MINOR_2);
if (atomicio(write, s, buf, n) != n) {
error("write (%s): %s", c->c_name, strerror(errno));
confree(s);
return;
}
+ if (c->c_keytype != KT_RSA1) {
+ keyprint(c, keygrab_ssh2(c));
+ confree(s);
+ return;
+ }
c->c_status = CS_SIZE;
contouch(s);
}
c->c_status = CS_KEYS;
break;
case CS_KEYS:
- keyprint(c->c_name, c->c_output_name, c->c_data, c->c_plen);
+ keyprint(c, keygrab_ssh1(c));
confree(s);
return;
break;
}
}
-static char *
-nexthost(int argc, char **argv)
+static void
+do_host(char *host)
{
- static Linebuf *lb;
-
- for (;;) {
- if (!lb) {
- if (argno >= argc)
- return (NULL);
- if (argv[argno][0] != '-')
- return (argv[argno++]);
- if (!strcmp(argv[argno], "--")) {
- if (++argno >= argc)
- return (NULL);
- return (argv[argno++]);
- } else if (!strncmp(argv[argno], "-f", 2)) {
- char *fname;
-
- if (argv[argno][2])
- fname = &argv[argno++][2];
- else if (++argno >= argc) {
- error("missing filename for `-f'");
- return (NULL);
- } else
- fname = argv[argno++];
- if (!strcmp(fname, "-"))
- fname = NULL;
- lb = Linebuf_alloc(fname, error);
- } else
- error("ignoring invalid/misplaced option `%s'",
- argv[argno++]);
- } else {
- char *line;
-
- line = Linebuf_getline(lb);
- if (line)
- return (line);
- Linebuf_free(lb);
- lb = NULL;
+ char *name = strnnsep(&host, " \t\n");
+ int j;
+
+ for (j = KT_RSA1; j <= KT_RSA; j *= 2) {
+ if (get_keytypes & j) {
+ while (ncon >= MAXCON)
+ conloop();
+ conalloc(name, *host ? host : name, j);
}
}
}
+static void
+fatal_callback(void *arg)
+{
+ if (nonfatal_fatal)
+ longjmp(kexjmp, -1);
+}
+
static void
usage(void)
{
- fprintf(stderr, "Usage: %s [options] [ host | addrlist namelist ]\n",
+ fprintf(stderr, "Usage: %s [options] host ...\n",
__progname);
fprintf(stderr, "Options:\n");
- fprintf(stderr, " -t timeout Set connection timeout.\n");
fprintf(stderr, " -f file Read hosts or addresses from file.\n");
+ fprintf(stderr, " -p port Connect to the specified port.\n");
+ fprintf(stderr, " -t keytype Specify the host key type.\n");
+ fprintf(stderr, " -T timeout Set connection timeout.\n");
+ fprintf(stderr, " -v Verbose; display verbose debugging messages.\n");
+ fprintf(stderr, " -4 Use IPv4 only.\n");
+ fprintf(stderr, " -6 Use IPv6 only.\n");
exit(1);
}
int
main(int argc, char **argv)
{
- char *host = NULL;
+ int debug_flag = 0, log_level = SYSLOG_LEVEL_INFO;
+ int opt, fopt_count = 0;
+ char *tname;
+
+ extern int optind;
+ extern char *optarg;
__progname = get_progname(argv[0]);
TAILQ_INIT(&tq);
- if (argc <= argno)
+ if (argc <= 1)
usage();
- if (argv[1][0] == '-' && argv[1][1] == 't') {
- argno++;
- if (argv[1][2])
- timeout = atoi(&argv[1][2]);
- else {
- if (argno >= argc)
+ while ((opt = getopt(argc, argv, "v46p:T:t:f:")) != -1) {
+ switch (opt) {
+ case 'p':
+ ssh_port = a2port(optarg);
+ if (ssh_port == 0) {
+ fprintf(stderr, "Bad port '%s'\n", optarg);
+ exit(1);
+ }
+ break;
+ case 'T':
+ timeout = atoi(optarg);
+ if (timeout <= 0)
usage();
- timeout = atoi(argv[argno++]);
- }
- if (timeout <= 0)
+ break;
+ case 'v':
+ if (!debug_flag) {
+ debug_flag = 1;
+ log_level = SYSLOG_LEVEL_DEBUG1;
+ }
+ else if (log_level < SYSLOG_LEVEL_DEBUG3)
+ log_level++;
+ else
+ fatal("Too high debugging level.");
+ break;
+ case 'f':
+ if (strcmp(optarg, "-") == 0)
+ optarg = NULL;
+ argv[fopt_count++] = optarg;
+ break;
+ case 't':
+ get_keytypes = 0;
+ tname = strtok(optarg, ",");
+ while (tname) {
+ int type = key_type_from_name(tname);
+ switch (type) {
+ case KEY_RSA1:
+ get_keytypes |= KT_RSA1;
+ break;
+ case KEY_DSA:
+ get_keytypes |= KT_DSA;
+ break;
+ case KEY_RSA:
+ get_keytypes |= KT_RSA;
+ break;
+ case KEY_UNSPEC:
+ fatal("unknown key type %s\n", tname);
+ }
+ tname = strtok(NULL, ",");
+ }
+ break;
+ case '4':
+ IPv4or6 = AF_INET;
+ break;
+ case '6':
+ IPv4or6 = AF_INET6;
+ break;
+ case '?':
+ default:
usage();
+ }
}
- if (argc <= argno)
+ if (optind == argc && !fopt_count)
usage();
+ log_init("ssh-keyscan", log_level, SYSLOG_FACILITY_USER, 1);
+ fatal_add_cleanup(fatal_callback, NULL);
+
+
maxfd = fdlim_get(1);
if (maxfd < 0)
fatal("%s: fdlim_get: bad value", __progname);
read_wait = xmalloc(read_wait_size);
memset(read_wait, 0, read_wait_size);
- do {
- while (ncon < MAXCON) {
- char *name;
-
- host = nexthost(argc, argv);
- if (host == NULL)
- break;
- name = strnnsep(&host, " \t\n");
- conalloc(name, *host ? host : name);
+ if (fopt_count) {
+ Linebuf *lb;
+ char *line;
+ int j;
+
+ for (j = 0; j < fopt_count; j++) {
+ lb = Linebuf_alloc(argv[j], error);
+ while ((line = Linebuf_getline(lb)) != NULL)
+ do_host(line);
+ Linebuf_free(lb);
}
- conloop();
- } while (host);
+ }
+
+ while (optind < argc)
+ do_host(argv[optind++]);
+
while (ncon > 0)
conloop();
andersk / openssh.git / commitdiff
