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- markus@cvs.openbsd.org 2001/08/05 23:18:20

Browse Source 
[ssh-keyscan.1 ssh-keyscan.c]
     ssh 2 support; from wayned@users.sourceforge.net
This commit is contained in:
Ben Lindstrom 2001-08-06 22:41:30 +00:00
parent ddfb1e3a89
commit 325e70c90f
3 changed files with 300 additions and 96 deletions
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5
ChangeLog
View File

@ -138,6 +138,9 @@
- jakob@cvs.openbsd.org 2001/08/03 10:31:30
[ssh-add.c ssh-agent.c ssh-keyscan.c]
improve usage(). ok markus@
- markus@cvs.openbsd.org 2001/08/05 23:18:20
[ssh-keyscan.1 ssh-keyscan.c]
ssh 2 support; from wayned@users.sourceforge.net
20010803
- (djm) Fix interrupted read in entropy gatherer. Spotted by markus@ on
@ -6248,4 +6251,4 @@
- Wrote replacements for strlcpy and mkdtemp
- Released 1.0pre1
$Id: ChangeLog,v 1.1462 2001/08/06 22:06:35 mouring Exp $
$Id: ChangeLog,v 1.1463 2001/08/06 22:41:30 mouring Exp $

75
ssh-keyscan.1
View File

@ -1,4 +1,4 @@
.\" $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>.
.\"
@ -14,9 +14,13 @@
.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
@ -37,14 +41,28 @@ any encryption.
.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.
@ -55,6 +73,19 @@ is supplied instead of a filename,
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
@ -67,7 +98,10 @@ On the other hand, if your security model allows such a risk,
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
@ -78,20 +112,36 @@ Find all hosts from the file
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
@ -99,3 +149,6 @@ key, and drops the connection as soon as it gets the key.
.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.

316
ssh-keyscan.c
View File

@ -7,7 +7,7 @@
*/
#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 $");
#if defined(HAVE_SYS_QUEUE_H) && !defined(HAVE_BOGUS_SYS_QUEUE_H)
#include <sys/queue.h>
@ -18,18 +18,37 @@ RCSID("$OpenBSD: ssh-keyscan.c,v 1.25 2001/08/03 10:31:30 jakob Exp $");
#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
@ -47,6 +66,8 @@ char *__progname;
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
@ -62,11 +83,13 @@ typedef struct Connection {
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;
@ -262,8 +285,8 @@ strnnsep(char **stringp, char *delim)
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;
@ -272,12 +295,12 @@ keyprint(char *host, char *output_name, char *kd, int len)
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 */
@ -290,10 +313,70 @@ keyprint(char *host, char *output_name, char *kd, int len)
(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);
}
@ -304,9 +387,9 @@ tcpconnect(char *host)
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));
@ -331,7 +414,7 @@ tcpconnect(char *host)
}
static int
conalloc(char *iname, char *oname)
conalloc(char *iname, char *oname, int keytype)
{
int s;
char *namebase, *name, *namelist;
@ -360,6 +443,7 @@ conalloc(char *iname, char *oname)
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);
@ -379,6 +463,7 @@ confree(int s)
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--;
@ -398,21 +483,16 @@ conrecycle(int s)
{
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];
@ -434,12 +514,34 @@ congreet(int 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);
}
@ -472,7 +574,7 @@ conread(int 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;
@ -536,86 +638,128 @@ conloop(void)
}
}
static char *
nexthost(int argc, char **argv)
static void
do_host(char *host)
{
static Linebuf *lb;
char *name = strnnsep(&host, " \t\n");
int j;
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;
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);
@ -632,18 +776,22 @@ main(int argc, char **argv)
read_wait = xmalloc(read_wait_size);
memset(read_wait, 0, read_wait_size);
do {
while (ncon < MAXCON) {
char *name;
if (fopt_count) {
Linebuf *lb;
char *line;
int j;
host = nexthost(argc, argv);
if (host == NULL)
break;
name = strnnsep(&host, " \t\n");
conalloc(name, *host ? host : name);
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();