* New upstream release (LP: #535029).

  - After a transition period of about 10 years, this release disables SSH
    protocol 1 by default.  Clients and servers that need to use the
    legacy protocol must explicitly enable it in ssh_config / sshd_config
    or on the command-line.
  - Remove the libsectok/OpenSC-based smartcard code and add support for
    PKCS#11 tokens.  This support is enabled by default in the Debian
    packaging, since it now doesn't involve additional library
    dependencies (closes: #231472, LP: #16918).
  - Add support for certificate authentication of users and hosts using a
    new, minimal OpenSSH certificate format (closes: #482806).
  - Added a 'netcat mode' to ssh(1): "ssh -W host:port ...".
  - Add the ability to revoke keys in sshd(8) and ssh(1).  (For the Debian
    package, this overlaps with the key blacklisting facility added in
    openssh 1:4.7p1-9, but with different file formats and slightly
    different scopes; for the moment, I've roughly merged the two.)
  - Various multiplexing improvements, including support for requesting
    port-forwardings via the multiplex protocol (closes: #360151).
  - Allow setting an explicit umask on the sftp-server(8) commandline to
    override whatever default the user has (closes: #496843).
  - Many sftp client improvements, including tab-completion, more options,
    and recursive transfer support for get/put (LP: #33378).  The old
    mget/mput commands never worked properly and have been removed
    (closes: #270399, #428082).
  - Do not prompt for a passphrase if we fail to open a keyfile, and log
    the reason why the open failed to debug (closes: #431538).
  - Prevent sftp from crashing when given a "-" without a command.  Also,
    allow whitespace to follow a "-" (closes: #531561).

1 files changed, 115 insertions, 62 deletions

diff --git a/sshd.c b/sshd.c
index 248ad2976..df6c9d24e 100644
--- a/sshd.c
+++ b/sshd.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: sshd.c,v 1.367 2009/05/28 16:50:16 andreas Exp $ */
+/* $OpenBSD: sshd.c,v 1.374 2010/03/07 11:57:13 dtucker Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -209,6 +209,7 @@ struct {
         Key     *server_key;            /* ephemeral server key */
         Key     *ssh1_host_key;         /* ssh1 host key */
         Key     **host_keys;            /* all private host keys */
+        Key     **host_certificates;    /* all public host certificates */
         int     have_ssh1_key;
         int     have_ssh2_key;
         u_char  ssh1_cookie[SSH_SESSION_KEY_LENGTH];
@@ -254,11 +255,6 @@ Buffer loginmsg;
 /* Unprivileged user */
 struct passwd *privsep_pw = NULL;
 
-#ifdef OOM_ADJUST
-/* Linux out-of-memory killer adjustment */
-static char oom_adj_save[8];
-#endif
-
 /* Prototypes for various functions defined later in this file. */
 void destroy_sensitive_data(void);
 void demote_sensitive_data(void);
@@ -555,6 +551,10 @@ destroy_sensitive_data(void)
                         key_free(sensitive_data.host_keys[i]);
                         sensitive_data.host_keys[i] = NULL;
                 }
+                if (sensitive_data.host_certificates[i]) {
+                        key_free(sensitive_data.host_certificates[i]);
+                        sensitive_data.host_certificates[i] = NULL;
+                }
         }
         sensitive_data.ssh1_host_key = NULL;
         memset(sensitive_data.ssh1_cookie, 0, SSH_SESSION_KEY_LENGTH);
@@ -581,6 +581,7 @@ demote_sensitive_data(void)
                         if (tmp->type == KEY_RSA1)
                                 sensitive_data.ssh1_host_key = tmp;
                 }
+                /* Certs do not need demotion */
         }
 
         /* We do not clear ssh1_host key and cookie.  XXX - Okay Niels? */
@@ -727,10 +728,11 @@ list_hostkey_types(void)
         const char *p;
         char *ret;
         int i;
+        Key *key;
 
         buffer_init(&b);
         for (i = 0; i < options.num_host_key_files; i++) {
-                Key *key = sensitive_data.host_keys[i];
+                key = sensitive_data.host_keys[i];
                 if (key == NULL)
                         continue;
                 switch (key->type) {
@@ -742,6 +744,19 @@ list_hostkey_types(void)
                         buffer_append(&b, p, strlen(p));
                         break;
                 }
+                /* If the private key has a cert peer, then list that too */
+                key = sensitive_data.host_certificates[i];
+                if (key == NULL)
+                        continue;
+                switch (key->type) {
+                case KEY_RSA_CERT:
+                case KEY_DSA_CERT:
+                        if (buffer_len(&b) > 0)
+                                buffer_append(&b, ",", 1);
+                        p = key_ssh_name(key);
+                        buffer_append(&b, p, strlen(p));
+                        break;
+                }
         }
         buffer_append(&b, "\0", 1);
         ret = xstrdup(buffer_ptr(&b));
@@ -750,20 +765,37 @@ list_hostkey_types(void)
         return ret;
 }
 
-Key *
-get_hostkey_by_type(int type)
+static Key *
+get_hostkey_by_type(int type, int need_private)
 {
         int i;
+        Key *key;
 
         for (i = 0; i < options.num_host_key_files; i++) {
-                Key *key = sensitive_data.host_keys[i];
+                if (type == KEY_RSA_CERT || type == KEY_DSA_CERT)
+                        key = sensitive_data.host_certificates[i];
+                else
+                        key = sensitive_data.host_keys[i];
                 if (key != NULL && key->type == type)
-                        return key;
+                        return need_private ?
+                            sensitive_data.host_keys[i] : key;
         }
         return NULL;
 }
 
 Key *
+get_hostkey_public_by_type(int type)
+{
+        return get_hostkey_by_type(type, 0);
+}
+
+Key *
+get_hostkey_private_by_type(int type)
+{
+        return get_hostkey_by_type(type, 1);
+}
+
+Key *
 get_hostkey_by_index(int ind)
 {
         if (ind < 0 || ind >= options.num_host_key_files)
@@ -777,8 +809,13 @@ get_hostkey_index(Key *key)
         int i;
 
         for (i = 0; i < options.num_host_key_files; i++) {
-                if (key == sensitive_data.host_keys[i])
-                        return (i);
+                if (key_is_cert(key)) {
+                        if (key == sensitive_data.host_certificates[i])
+                                return (i);
+                } else {
+                        if (key == sensitive_data.host_keys[i])
+                                return (i);
+                }
         }
         return (-1);
 }
@@ -817,9 +854,9 @@ usage(void)
         fprintf(stderr, "%s, %s\n",
             SSH_RELEASE, SSLeay_version(SSLEAY_VERSION));
         fprintf(stderr,
-"usage: sshd [-46DdeiqTt] [-b bits] [-C connection_spec] [-f config_file]\n"
-"            [-g login_grace_time] [-h host_key_file] [-k key_gen_time]\n"
-"            [-o option] [-p port] [-u len]\n"
+"usage: sshd [-46DdeiqTt] [-b bits] [-C connection_spec] [-c host_cert_file]\n"
+"            [-f config_file] [-g login_grace_time] [-h host_key_file]\n"
+"            [-k key_gen_time] [-o option] [-p port] [-u len]\n"
         );
         exit(1);
 }
@@ -915,31 +952,6 @@ recv_rexec_state(int fd, Buffer *conf)
         debug3("%s: done", __func__);
 }
 
-#ifdef OOM_ADJUST
-/*
- * If requested in the environment, tell the Linux kernel's out-of-memory
- * killer to avoid sshd. The old state will be restored when forking child
- * processes.
- */
-static void
-oom_adjust_startup(void)
-{
-        const char *oom_adj = getenv("SSHD_OOM_ADJUST");
-
-        if (!oom_adj || !*oom_adj)
-                return;
-        oom_adj_get(oom_adj_save, sizeof(oom_adj_save));
-        oom_adj_set(oom_adj);
-}
-
-static void
-oom_restore(void)
-{
-        if (oom_adj_save[0])
-                oom_adj_set(oom_adj_save);
-}
-#endif
-
 /* Accept a connection from inetd */
 static void
 server_accept_inetd(int *sock_in, int *sock_out)
@@ -1015,15 +1027,9 @@ server_listen(void)
                     &on, sizeof(on)) == -1)
                         error("setsockopt SO_REUSEADDR: %s", strerror(errno));
 
-#ifdef IPV6_V6ONLY
                 /* Only communicate in IPv6 over AF_INET6 sockets. */
-                if (ai->ai_family == AF_INET6) {
-                        if (setsockopt(listen_sock, IPPROTO_IPV6, IPV6_V6ONLY,
-                            &on, sizeof(on)) == -1)
-                                error("setsockopt IPV6_V6ONLY: %s",
-                                    strerror(errno));
-                }
-#endif
+                if (ai->ai_family == AF_INET6)
+                        sock_set_v6only(listen_sock);
 
                 debug("Bind to port %s on %s.", strport, ntop);
 
@@ -1277,7 +1283,7 @@ main(int ac, char **av)
 {
         extern char *optarg;
         extern int optind;
-        int opt, i, on = 1;
+        int opt, i, j, on = 1;
         int sock_in = -1, sock_out = -1, newsock = -1;
         const char *remote_ip;
         char *test_user = NULL, *test_host = NULL, *test_addr = NULL;
@@ -1330,6 +1336,14 @@ main(int ac, char **av)
                 case 'f':
                         config_file_name = optarg;
                         break;
+                case 'c':
+                        if (options.num_host_cert_files >= MAX_HOSTCERTS) {
+                                fprintf(stderr, "too many host certificates.\n");
+                                exit(1);
+                        }
+                        options.host_cert_files[options.num_host_cert_files++] =
+                           derelativise_path(optarg);
+                        break;
                 case 'd':
                         if (debug_flag == 0) {
                                 debug_flag = 1;
@@ -1397,7 +1411,8 @@ main(int ac, char **av)
                                 fprintf(stderr, "too many host keys.\n");
                                 exit(1);
                         }
-                        options.host_key_files[options.num_host_key_files++] = optarg;
+                        options.host_key_files[options.num_host_key_files++] = 
+                           derelativise_path(optarg);
                         break;
                 case 't':
                         test_flag = 1;
@@ -1555,7 +1570,7 @@ main(int ac, char **av)
                         sensitive_data.host_keys[i] = NULL;
                         continue;
                 }
-                if (reject_blacklisted_key(key, 1) == 1) {
+                if (auth_key_is_revoked(key, 1)) {
                         key_free(key);
                         sensitive_data.host_keys[i] = NULL;
                         continue;
@@ -1589,6 +1604,46 @@ main(int ac, char **av)
                 exit(1);
         }
 
+        /*
+         * Load certificates. They are stored in an array at identical
+         * indices to the public keys that they relate to.
+         */
+        sensitive_data.host_certificates = xcalloc(options.num_host_key_files,
+            sizeof(Key *));
+        for (i = 0; i < options.num_host_key_files; i++)
+                sensitive_data.host_certificates[i] = NULL;
+
+        for (i = 0; i < options.num_host_cert_files; i++) {
+                key = key_load_public(options.host_cert_files[i], NULL);
+                if (key == NULL) {
+                        error("Could not load host certificate: %s",
+                            options.host_cert_files[i]);
+                        continue;
+                }
+                if (!key_is_cert(key)) {
+                        error("Certificate file is not a certificate: %s",
+                            options.host_cert_files[i]);
+                        key_free(key);
+                        continue;
+                }
+                /* Find matching private key */
+                for (j = 0; j < options.num_host_key_files; j++) {
+                        if (key_equal_public(key,
+                            sensitive_data.host_keys[j])) {
+                                sensitive_data.host_certificates[j] = key;
+                                break;
+                        }
+                }
+                if (j >= options.num_host_key_files) {
+                        error("No matching private key for certificate: %s",
+                            options.host_cert_files[i]);
+                        key_free(key);
+                        continue;
+                }
+                sensitive_data.host_certificates[j] = key;
+                debug("host certificate: #%d type %d %s", j, key->type,
+                    key_type(key));
+        }
         /* Check certain values for sanity. */
         if (options.protocol & SSH_PROTO_1) {
                 if (options.server_key_bits < 512 ||
@@ -1707,15 +1762,11 @@ main(int ac, char **av)
         /* ignore SIGPIPE */
         signal(SIGPIPE, SIG_IGN);
 
-#ifdef OOM_ADJUST
-        /* Adjust out-of-memory killer */
-        oom_adjust_startup();
-#endif
-
         /* Get a connection, either from inetd or a listening TCP socket */
         if (inetd_flag) {
                 server_accept_inetd(&sock_in, &sock_out);
         } else {
+                platform_pre_listen();
                 server_listen();
 
                 if (options.protocol & SSH_PROTO_1)
@@ -1750,10 +1801,6 @@ main(int ac, char **av)
         /* This is the child processing a new connection. */
         setproctitle("%s", "[accepted]");
 
-#ifdef OOM_ADJUST
-        oom_restore();
-#endif
-
         /*
          * Create a new session and process group since the 4.4BSD
          * setlogin() affects the entire process group.  We don't
@@ -1809,6 +1856,10 @@ main(int ac, char **av)
                     sock_in, sock_out, newsock, startup_pipe, config_s[0]);
         }
 
+        /* Executed child processes don't need these. */
+        fcntl(sock_out, F_SETFD, FD_CLOEXEC);
+        fcntl(sock_in, F_SETFD, FD_CLOEXEC);
+
         /*
          * Disable the key regeneration alarm.  We will not regenerate the
          * key since we are no longer in a position to give it to anyone. We
@@ -1960,6 +2011,7 @@ main(int ac, char **av)
 
         /* prepare buffer to collect messages to display to user after login */
         buffer_init(&loginmsg);
+        auth_debug_reset();
 
         if (use_privsep)
                 if (privsep_preauth(authctxt) == 1)
@@ -2365,7 +2417,8 @@ do_ssh2_kex(void)
         kex->server = 1;
         kex->client_version_string=client_version_string;
         kex->server_version_string=server_version_string;
-        kex->load_host_key=&get_hostkey_by_type;
+        kex->load_host_public_key=&get_hostkey_public_by_type;
+        kex->load_host_private_key=&get_hostkey_private_by_type;
         kex->host_key_index=&get_hostkey_index;
 
         xxx_kex = kex;