- djm@cvs.openbsd.org 2010/11/29 23:45:51
[auth.c hostfile.c hostfile.h ssh.c ssh_config.5 sshconnect.c]
[sshconnect.h sshconnect2.c]
automatically order the hostkeys requested by the client based on
which hostkeys are already recorded in known_hosts. This avoids
hostkey warnings when connecting to servers with new ECDSA keys
that are preferred by default; with markus@
diff --git a/sshconnect.c b/sshconnect.c
index 78068c6..064bb74 100644
--- a/sshconnect.c
+++ b/sshconnect.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: sshconnect.c,v 1.228 2010/10/06 21:10:21 djm Exp $ */
+/* $OpenBSD: sshconnect.c,v 1.229 2010/11/29 23:45:51 djm Exp $ */
/*
* Author: Tatu Ylonen <ylo@cs.hut.fi>
* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -75,7 +75,7 @@
extern uid_t original_real_uid;
extern uid_t original_effective_uid;
-static int show_other_keys(const char *, Key *);
+static int show_other_keys(struct hostkeys *, Key *);
static void warn_changed_key(Key *);
/*
@@ -607,6 +607,79 @@
return 1;
}
+static int
+sockaddr_is_local(struct sockaddr *hostaddr)
+{
+ switch (hostaddr->sa_family) {
+ case AF_INET:
+ return (ntohl(((struct sockaddr_in *)hostaddr)->
+ sin_addr.s_addr) >> 24) == IN_LOOPBACKNET;
+ case AF_INET6:
+ return IN6_IS_ADDR_LOOPBACK(
+ &(((struct sockaddr_in6 *)hostaddr)->sin6_addr));
+ default:
+ return 0;
+ }
+}
+
+/*
+ * Prepare the hostname and ip address strings that are used to lookup
+ * host keys in known_hosts files. These may have a port number appended.
+ */
+void
+get_hostfile_hostname_ipaddr(char *hostname, struct sockaddr *hostaddr,
+ u_short port, char **hostfile_hostname, char **hostfile_ipaddr)
+{
+ char ntop[NI_MAXHOST];
+ socklen_t addrlen;
+
+ switch (hostaddr == NULL ? -1 : hostaddr->sa_family) {
+ case -1:
+ addrlen = 0;
+ break;
+ case AF_INET:
+ addrlen = sizeof(struct sockaddr_in);
+ break;
+ case AF_INET6:
+ addrlen = sizeof(struct sockaddr_in6);
+ break;
+ default:
+ addrlen = sizeof(struct sockaddr);
+ break;
+ }
+
+ /*
+ * We don't have the remote ip-address for connections
+ * using a proxy command
+ */
+ if (hostfile_ipaddr != NULL) {
+ if (options.proxy_command == NULL) {
+ if (getnameinfo(hostaddr, addrlen,
+ ntop, sizeof(ntop), NULL, 0, NI_NUMERICHOST) != 0)
+ fatal("check_host_key: getnameinfo failed");
+ *hostfile_ipaddr = put_host_port(ntop, port);
+ } else {
+ *hostfile_ipaddr = xstrdup("<no hostip for proxy "
+ "command>");
+ }
+ }
+
+ /*
+ * Allow the user to record the key under a different name or
+ * differentiate a non-standard port. This is useful for ssh
+ * tunneling over forwarded connections or if you run multiple
+ * sshd's on different ports on the same machine.
+ */
+ if (hostfile_hostname != NULL) {
+ if (options.host_key_alias != NULL) {
+ *hostfile_hostname = xstrdup(options.host_key_alias);
+ debug("using hostkeyalias: %s", *hostfile_hostname);
+ } else {
+ *hostfile_hostname = put_host_port(hostname, port);
+ }
+ }
+}
+
/*
* check whether the supplied host key is valid, return -1 if the key
* is not valid. the user_hostfile will not be updated if 'readonly' is true.
@@ -616,21 +689,21 @@
#define ROQUIET 2
static int
check_host_key(char *hostname, struct sockaddr *hostaddr, u_short port,
- Key *host_key, int readonly, const char *user_hostfile,
- const char *system_hostfile)
+ Key *host_key, int readonly, char *user_hostfile,
+ char *system_hostfile)
{
- Key *file_key, *raw_key = NULL;
+ Key *raw_key = NULL;
const char *type;
char *ip = NULL, *host = NULL;
char hostline[1000], *hostp, *fp, *ra;
HostStatus host_status;
HostStatus ip_status;
- int r, want_cert, local = 0, host_ip_differ = 0;
- int salen;
- char ntop[NI_MAXHOST];
+ int r, want_cert = key_is_cert(host_key), host_ip_differ = 0;
+ int local = sockaddr_is_local(hostaddr);
char msg[1024];
- int len, host_line, ip_line, cancelled_forwarding = 0;
- const char *host_file = NULL, *ip_file = NULL;
+ int len, cancelled_forwarding = 0;
+ struct hostkeys *host_hostkeys, *ip_hostkeys;
+ const struct hostkey_entry *host_found, *ip_found;
/*
* Force accepting of the host key for loopback/localhost. The
@@ -640,23 +713,6 @@
* essentially disables host authentication for localhost; however,
* this is probably not a real problem.
*/
- /** hostaddr == 0! */
- switch (hostaddr->sa_family) {
- case AF_INET:
- local = (ntohl(((struct sockaddr_in *)hostaddr)->
- sin_addr.s_addr) >> 24) == IN_LOOPBACKNET;
- salen = sizeof(struct sockaddr_in);
- break;
- case AF_INET6:
- local = IN6_IS_ADDR_LOOPBACK(
- &(((struct sockaddr_in6 *)hostaddr)->sin6_addr));
- salen = sizeof(struct sockaddr_in6);
- break;
- default:
- local = 0;
- salen = sizeof(struct sockaddr_storage);
- break;
- }
if (options.no_host_authentication_for_localhost == 1 && local &&
options.host_key_alias == NULL) {
debug("Forcing accepting of host key for "
@@ -665,17 +721,10 @@
}
/*
- * We don't have the remote ip-address for connections
- * using a proxy command
+ * Prepare the hostname and address strings used for hostkey lookup.
+ * In some cases, these will have a port number appended.
*/
- if (options.proxy_command == NULL) {
- if (getnameinfo(hostaddr, salen, ntop, sizeof(ntop),
- NULL, 0, NI_NUMERICHOST) != 0)
- fatal("check_host_key: getnameinfo failed");
- ip = put_host_port(ntop, port);
- } else {
- ip = xstrdup("<no hostip for proxy command>");
- }
+ get_hostfile_hostname_ipaddr(hostname, hostaddr, port, &host, &ip);
/*
* Turn off check_host_ip if the connection is to localhost, via proxy
@@ -685,74 +734,52 @@
strcmp(hostname, ip) == 0 || options.proxy_command != NULL))
options.check_host_ip = 0;
- /*
- * Allow the user to record the key under a different name or
- * differentiate a non-standard port. This is useful for ssh
- * tunneling over forwarded connections or if you run multiple
- * sshd's on different ports on the same machine.
- */
- if (options.host_key_alias != NULL) {
- host = xstrdup(options.host_key_alias);
- debug("using hostkeyalias: %s", host);
- } else {
- host = put_host_port(hostname, port);
+ host_hostkeys = init_hostkeys();
+ load_hostkeys(host_hostkeys, host, user_hostfile);
+ load_hostkeys(host_hostkeys, host, system_hostfile);
+
+ ip_hostkeys = NULL;
+ if (!want_cert && options.check_host_ip) {
+ ip_hostkeys = init_hostkeys();
+ load_hostkeys(ip_hostkeys, ip, user_hostfile);
+ load_hostkeys(ip_hostkeys, ip, system_hostfile);
}
retry:
+ /* Reload these as they may have changed on cert->key downgrade */
want_cert = key_is_cert(host_key);
type = key_type(host_key);
/*
- * Store the host key from the known host file in here so that we can
- * compare it with the key for the IP address.
- */
- file_key = key_new(key_is_cert(host_key) ? KEY_UNSPEC : host_key->type);
-
- /*
* Check if the host key is present in the user's list of known
* hosts or in the systemwide list.
*/
- host_file = user_hostfile;
- host_status = check_host_in_hostfile(host_file, host, host_key,
- file_key, &host_line);
- if (host_status == HOST_NEW) {
- host_file = system_hostfile;
- host_status = check_host_in_hostfile(host_file, host, host_key,
- file_key, &host_line);
- }
+ host_status = check_key_in_hostkeys(host_hostkeys, host_key,
+ &host_found);
+
/*
* Also perform check for the ip address, skip the check if we are
* localhost, looking for a certificate, or the hostname was an ip
* address to begin with.
*/
- if (!want_cert && options.check_host_ip) {
- Key *ip_key = key_new(host_key->type);
-
- ip_file = user_hostfile;
- ip_status = check_host_in_hostfile(ip_file, ip, host_key,
- ip_key, &ip_line);
- if (ip_status == HOST_NEW) {
- ip_file = system_hostfile;
- ip_status = check_host_in_hostfile(ip_file, ip,
- host_key, ip_key, &ip_line);
- }
+ if (!want_cert && ip_hostkeys != NULL) {
+ ip_status = check_key_in_hostkeys(ip_hostkeys, host_key,
+ &ip_found);
if (host_status == HOST_CHANGED &&
- (ip_status != HOST_CHANGED || !key_equal(ip_key, file_key)))
+ (ip_status != HOST_CHANGED ||
+ (ip_found != NULL &&
+ !key_equal(ip_found->key, host_found->key))))
host_ip_differ = 1;
-
- key_free(ip_key);
} else
ip_status = host_status;
- key_free(file_key);
-
switch (host_status) {
case HOST_OK:
/* The host is known and the key matches. */
debug("Host '%.200s' is known and matches the %s host %s.",
host, type, want_cert ? "certificate" : "key");
- debug("Found %s in %s:%d",
- want_cert ? "CA key" : "key", host_file, host_line);
+ debug("Found %s in %s:%lu", want_cert ? "CA key" : "key",
+ host_found->file, host_found->line);
if (want_cert && !check_host_cert(hostname, host_key))
goto fail;
if (options.check_host_ip && ip_status == HOST_NEW) {
@@ -803,7 +830,7 @@
} else if (options.strict_host_key_checking == 2) {
char msg1[1024], msg2[1024];
- if (show_other_keys(host, host_key))
+ if (show_other_keys(host_hostkeys, host_key))
snprintf(msg1, sizeof(msg1),
"\nbut keys of different type are already"
" known for this host.");
@@ -844,8 +871,7 @@
* local known_hosts file.
*/
if (options.check_host_ip && ip_status == HOST_NEW) {
- snprintf(hostline, sizeof(hostline), "%s,%s",
- host, ip);
+ snprintf(hostline, sizeof(hostline), "%s,%s", host, ip);
hostp = hostline;
if (options.hash_known_hosts) {
/* Add hash of host and IP separately */
@@ -899,8 +925,8 @@
* all hosts that one might visit.
*/
debug("Host certificate authority does not "
- "match %s in %s:%d", CA_MARKER,
- host_file, host_line);
+ "match %s in %s:%lu", CA_MARKER,
+ host_found->file, host_found->line);
goto fail;
}
if (readonly == ROQUIET)
@@ -922,13 +948,15 @@
error("DNS SPOOFING is happening or the IP address for the host");
error("and its host key have changed at the same time.");
if (ip_status != HOST_NEW)
- error("Offending key for IP in %s:%d", ip_file, ip_line);
+ error("Offending key for IP in %s:%lu",
+ ip_found->file, ip_found->line);
}
/* The host key has changed. */
warn_changed_key(host_key);
error("Add correct host key in %.100s to get rid of this message.",
user_hostfile);
- error("Offending key in %s:%d", host_file, host_line);
+ error("Offending %s key in %s:%lu", key_type(host_found->key),
+ host_found->file, host_found->line);
/*
* If strict host key checking is in use, the user will have
@@ -1013,13 +1041,13 @@
snprintf(msg, sizeof(msg),
"Warning: the %s host key for '%.200s' "
"differs from the key for the IP address '%.128s'"
- "\nOffending key for IP in %s:%d",
- type, host, ip, ip_file, ip_line);
+ "\nOffending key for IP in %s:%lu",
+ type, host, ip, ip_found->file, ip_found->line);
if (host_status == HOST_OK) {
len = strlen(msg);
snprintf(msg + len, sizeof(msg) - len,
- "\nMatching host key in %s:%d",
- host_file, host_line);
+ "\nMatching host key in %s:%lu",
+ host_found->file, host_found->line);
}
if (options.strict_host_key_checking == 1) {
logit("%s", msg);
@@ -1037,6 +1065,10 @@
xfree(ip);
xfree(host);
+ if (host_hostkeys != NULL)
+ free_hostkeys(host_hostkeys);
+ if (ip_hostkeys != NULL)
+ free_hostkeys(ip_hostkeys);
return 0;
fail:
@@ -1056,6 +1088,10 @@
key_free(raw_key);
xfree(ip);
xfree(host);
+ if (host_hostkeys != NULL)
+ free_hostkeys(host_hostkeys);
+ if (ip_hostkeys != NULL)
+ free_hostkeys(ip_hostkeys);
return -1;
}
@@ -1065,6 +1101,11 @@
{
struct stat st;
int flags = 0;
+ char *fp;
+
+ fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
+ debug("Server host key: %s %s", key_type(host_key), fp);
+ xfree(fp);
/* XXX certs are not yet supported for DNS */
if (!key_is_cert(host_key) && options.verify_host_key_dns &&
@@ -1108,7 +1149,7 @@
*/
void
ssh_login(Sensitive *sensitive, const char *orighost,
- struct sockaddr *hostaddr, struct passwd *pw, int timeout_ms)
+ struct sockaddr *hostaddr, u_short port, struct passwd *pw, int timeout_ms)
{
char *host, *cp;
char *server_user, *local_user;
@@ -1131,7 +1172,7 @@
/* key exchange */
/* authenticate user */
if (compat20) {
- ssh_kex2(host, hostaddr);
+ ssh_kex2(host, hostaddr, port);
ssh_userauth2(local_user, server_user, host, sensitive);
} else {
ssh_kex(host, hostaddr);
@@ -1158,61 +1199,35 @@
xfree(padded);
}
-static int
-show_key_from_file(const char *file, const char *host, int keytype)
-{
- Key *found;
- char *fp, *ra;
- int line, ret;
-
- found = key_new(keytype);
- if ((ret = lookup_key_in_hostfile_by_type(file, host,
- keytype, found, &line))) {
- fp = key_fingerprint(found, SSH_FP_MD5, SSH_FP_HEX);
- ra = key_fingerprint(found, SSH_FP_MD5, SSH_FP_RANDOMART);
- logit("WARNING: %s key found for host %s\n"
- "in %s:%d\n"
- "%s key fingerprint %s.\n%s\n",
- key_type(found), host, file, line,
- key_type(found), fp, ra);
- xfree(ra);
- xfree(fp);
- }
- key_free(found);
- return (ret);
-}
-
/* print all known host keys for a given host, but skip keys of given type */
static int
-show_other_keys(const char *host, Key *key)
+show_other_keys(struct hostkeys *hostkeys, Key *key)
{
int type[] = { KEY_RSA1, KEY_RSA, KEY_DSA, KEY_ECDSA, -1};
- int i, found = 0;
+ int i, ret = 0;
+ char *fp, *ra;
+ const struct hostkey_entry *found;
for (i = 0; type[i] != -1; i++) {
if (type[i] == key->type)
continue;
- if (type[i] != KEY_RSA1 &&
- show_key_from_file(options.user_hostfile2, host, type[i])) {
- found = 1;
+ if (!lookup_key_in_hostkeys_by_type(hostkeys, type[i], &found))
continue;
- }
- if (type[i] != KEY_RSA1 &&
- show_key_from_file(options.system_hostfile2, host, type[i])) {
- found = 1;
- continue;
- }
- if (show_key_from_file(options.user_hostfile, host, type[i])) {
- found = 1;
- continue;
- }
- if (show_key_from_file(options.system_hostfile, host, type[i])) {
- found = 1;
- continue;
- }
- debug2("no key of type %d for host %s", type[i], host);
+ fp = key_fingerprint(found->key, SSH_FP_MD5, SSH_FP_HEX);
+ ra = key_fingerprint(found->key, SSH_FP_MD5, SSH_FP_RANDOMART);
+ logit("WARNING: %s key found for host %s\n"
+ "in %s:%lu\n"
+ "%s key fingerprint %s.",
+ key_type(found->key),
+ found->host, found->file, found->line,
+ key_type(found->key), fp);
+ if (options.visual_host_key)
+ logit("%s", ra);
+ xfree(ra);
+ xfree(fp);
+ ret = 1;
}
- return (found);
+ return ret;
}
static void