 @@ -1,473 +1,462 @@
-/*	$NetBSD: pam_ssh.c,v 1.17 2011/05/06 17:22:09 drochner Exp $	*/
+/*	$NetBSD: pam_ssh.c,v 1.18 2011/12/16 17:30:12 drochner Exp $	*/
 /*-
  * Copyright (c) 2003 Networks Associates Technology, Inc.
  * All rights reserved.
+ *
  * This software was developed for the FreeBSD Project by ThinkSec AS and
  * NAI Labs, the Security Research Division of Network Associates, Inc.
  * under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), as part of the
  * DARPA CHATS research program.
+ *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  * 3. The name of the author may not be used to endorse or promote
  *    products derived from this software without specific prior written
  *    permission.
+ *
  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  */
 #include <sys/cdefs.h>
 #ifdef __FreeBSD__
 __FBSDID("$FreeBSD: src/lib/libpam/modules/pam_ssh/pam_ssh.c,v 1.40 2004/02/10 10:13:21 des Exp $");
 #else
-__RCSID("$NetBSD: pam_ssh.c,v 1.17 2011/05/06 17:22:09 drochner Exp $");
+__RCSID("$NetBSD: pam_ssh.c,v 1.18 2011/12/16 17:30:12 drochner Exp $");
 #endif
 #include <sys/param.h>
 #include <sys/wait.h>
 #include <errno.h>
 #include <fcntl.h>
 #include <paths.h>
 #include <pwd.h>
 #include <signal.h>
 #include <stdio.h>
 #include <string.h>
 #include <unistd.h>
 #define PAM_SM_AUTH
 #define PAM_SM_SESSION
 #include <security/pam_appl.h>
 #include <security/pam_modules.h>
 #include <security/openpam.h>
 #include <openssl/evp.h>
 #include "key.h"
 #include "buffer.h"
 #include "authfd.h"
 #include "authfile.h"
 #define ssh_add_identity(auth, key, comment) \
 	ssh_add_identity_constrained(auth, key, comment, 0, 0)
 extern char **environ;
 struct pam_ssh_key {
 	Key	*key;
 	char	*comment;
 };
 static const char *pam_ssh_prompt = "SSH passphrase: ";
 static const char *pam_ssh_have_keys = "pam_ssh_have_keys";
 static const char *pam_ssh_keyfiles[] = {
 	".ssh/identity",	/* SSH1 RSA key */
 	".ssh/id_rsa",		/* SSH2 RSA key */
 	".ssh/id_dsa",		/* SSH2 DSA key */
 	NULL
 };
 static const char *pam_ssh_agent = "/usr/bin/ssh-agent";
-static const char *pam_ssh_agent_argv[] = { "ssh_agent", "-s", NULL };
+static const char *const pam_ssh_agent_argv[] = { "ssh_agent", "-s", NULL };
-static const char *pam_ssh_agent_envp[] = { NULL };
+static const char *const pam_ssh_agent_envp[] = { NULL };
 /*
  * Attempts to load a private key from the specified file in the specified
  * directory, using the specified passphrase.  If successful, returns a
  * struct pam_ssh_key containing the key and its comment.
  */
 static struct pam_ssh_key *
-pam_ssh_load_key(struct passwd *pwd, const char *kfn, const char *passphrase)
+pam_ssh_load_key(const char *dir, const char *kfn, const char *passphrase)
+{
 	struct pam_ssh_key *psk;
 	char fn[PATH_MAX];
 	char *comment;
 	Key *key;
-	if (snprintf(fn, sizeof(fn), "%s/%s", pwd->pw_dir, kfn) >
+	if (snprintf(fn, sizeof(fn), "%s/%s", dir, kfn) > (int)sizeof(fn))
 	    (int)sizeof(fn))
 		return (NULL);
 	comment = NULL;
 	key = key_load_private(fn, passphrase, &comment);
 	if (key == NULL) {
 		openpam_log(PAM_LOG_DEBUG, "failed to load key from %s", fn);
 		if (comment != NULL)
 			free(comment);
 		return (NULL);
+	}
 	openpam_log(PAM_LOG_DEBUG, "loaded '%s' from %s", comment, fn);
 	if ((psk = malloc(sizeof(*psk))) == NULL) {
 		key_free(key);
 		free(comment);
 		return (NULL);
+	}
 	psk->key = key;
 	psk->comment = comment;
 	return (psk);
+}
 /*
  * Wipes a private key and frees the associated resources.
  */
 static void
 pam_ssh_free_key(pam_handle_t *pamh __unused,
     void *data, int pam_err __unused)
+{
 	struct pam_ssh_key *psk;
 	psk = data;
 	key_free(psk->key);
 	free(psk->comment);
 	free(psk);
+}
 PAM_EXTERN int
 pam_sm_authenticate(pam_handle_t *pamh, int flags __unused,
     int argc __unused, const char *argv[] __unused)
+{
 	const char **kfn, *passphrase, *user;
 	const void *item;
 	struct passwd *pwd, pwres;
 	struct pam_ssh_key *psk;
 	int nkeys, pam_err, pass;
 	char pwbuf[1024];
 	/* PEM is not loaded by default */
 	OpenSSL_add_all_algorithms();
 	/* get user name and home directory */
 	pam_err = pam_get_user(pamh, &user, NULL);
 	if (pam_err != PAM_SUCCESS)
 		return (pam_err);
 	if (getpwnam_r(user, &pwres, pwbuf, sizeof(pwbuf), &pwd) != 0 ||
 	    pwd == NULL)
 		return (PAM_USER_UNKNOWN);
 	if (pwd->pw_dir == NULL)
 		return (PAM_AUTH_ERR);
 	/* switch to user credentials */
 	pam_err = openpam_borrow_cred(pamh, pwd);
 	if (pam_err != PAM_SUCCESS)
 		return (pam_err);
-#ifdef notyet
+	pass = (pam_get_item(pamh, PAM_AUTHTOK, &item) == PAM_SUCCESS &&
-	for (kfn = pam_ssh_keyfiles; *kfn != NULL; ++kfn) {
+	    item != NULL);
 		char path[MAXPATHLEN];
 		(void)snprintf(path, sizeof(path), "%s/%s", pwd->pw_dir, *kfn);
 		if (access(path, R_OK) == 0)
 			break;
 	if (*kfn == NULL) {
 		openpam_restore_cred(pamh);
 		return (PAM_AUTH_ERR);
 #endif
 	pass = (pam_get_item(pamh, PAM_AUTHTOK,
 	    (const void **)__UNCONST(&passphrase)) == PAM_SUCCESS);
  load_keys:
 	/* get passphrase */
 	pam_err = pam_get_authtok(pamh, PAM_AUTHTOK,
 	    &passphrase, pam_ssh_prompt);
 	if (pam_err != PAM_SUCCESS) {
 		openpam_restore_cred(pamh);
 		return (pam_err);
+	}
 	/* try to load keys from all keyfiles we know of */
 	nkeys = 0;
 	for (kfn = pam_ssh_keyfiles; *kfn != NULL; ++kfn) {
-		psk = pam_ssh_load_key(pwd, *kfn, passphrase);
+		psk = pam_ssh_load_key(pwd->pw_dir, *kfn, passphrase);
 		if (psk != NULL) {
 			pam_set_data(pamh, *kfn, psk, pam_ssh_free_key);
 			++nkeys;
+		}
+	}
 	/*
 	 * If we tried an old token and didn't get anything, and
 	 * try_first_pass was specified, try again after prompting the
 	 * user for a new passphrase.
 	 */
 	if (nkeys == 0 && pass == 1 &&
 	    openpam_get_option(pamh, "try_first_pass") != NULL) {
 		pam_set_item(pamh, PAM_AUTHTOK, NULL);
 		pass = 0;
 		goto load_keys;
+	}
 	/* switch back to arbitrator credentials before returning */
 	openpam_restore_cred(pamh);
 	/* no keys? */
 	if (nkeys == 0)
 		return (PAM_AUTH_ERR);
 	pam_set_data(pamh, pam_ssh_have_keys, NULL, NULL);
 	return (PAM_SUCCESS);
+}
 PAM_EXTERN int
 pam_sm_setcred(pam_handle_t *pamh __unused, int flags __unused,
     int argc __unused, const char *argv[] __unused)
+{
 	return (PAM_SUCCESS);
+}
 /*
  * Parses a line from ssh-agent's output.
  */
 static void
 pam_ssh_process_agent_output(pam_handle_t *pamh, FILE *f)
+{
 	char *line, *p, *key, *val;
 	size_t len;
 	while ((line = fgetln(f, &len)) != NULL) {
 		if (len < 4 || strncmp(line, "SSH_", 4) != 0)
 			continue;
 		/* find equal sign at end of key */
 		for (p = key = line; p < line + len; ++p)
 			if (*p == '=')
 				break;
 		if (p == line + len || *p != '=')
 			continue;
 		*p = '\0';
 		/* find semicolon at end of value */
 		for (val = ++p; p < line + len; ++p)
 			if (*p == ';')
 				break;
 		if (p == line + len || *p != ';')
 			continue;
 		*p = '\0';
 		/* store key-value pair in environment */
 		openpam_log(PAM_LOG_DEBUG, "got %s: %s", key, val);
 		pam_setenv(pamh, key, val, 1);
+	}
+}
 /*
  * Starts an ssh agent and stores the environment variables derived from
  * its output.
  */
 static int
 pam_ssh_start_agent(pam_handle_t *pamh, struct passwd *pwd)
+{
 	int agent_pipe[2];
 	pid_t pid;
 	FILE *f;
 	/* get a pipe which we will use to read the agent's output */
 	if (pipe(agent_pipe) == -1)
 		return (PAM_SYSTEM_ERR);
 	/* start the agent */
 	openpam_log(PAM_LOG_DEBUG, "starting an ssh agent");
 	pid = fork();
 	if (pid == (pid_t)-1) {
 		/* failed */
 		close(agent_pipe[0]);
 		close(agent_pipe[1]);
 		return (PAM_SYSTEM_ERR);
+	}
 	if (pid == 0) {
 #ifndef F_CLOSEM
 		int fd;
 #endif
 		/* child: drop privs, close fds and start agent */
 		if (setgid(pwd->pw_gid) == -1) {
 			openpam_log(PAM_LOG_DEBUG, "%s: Cannot setgid %d (%m)",
 			    __func__, (int)pwd->pw_gid);
 			goto done;
+		}
 		if (initgroups(pwd->pw_name, pwd->pw_gid) == -1) {
 			openpam_log(PAM_LOG_DEBUG,
 			    "%s: Cannot initgroups for %s (%m)",
 			    __func__, pwd->pw_name);
 			goto done;
+		}
 		if (setuid(pwd->pw_uid) == -1) {
 			openpam_log(PAM_LOG_DEBUG, "%s: Cannot setuid %d (%m)",
 			    __func__, (int)pwd->pw_uid);
 			goto done;
+		}
 		(void)close(STDIN_FILENO);
 		(void)open(_PATH_DEVNULL, O_RDONLY);
 		(void)dup2(agent_pipe[1], STDOUT_FILENO);
 		(void)dup2(agent_pipe[1], STDERR_FILENO);
 #ifdef F_CLOSEM
 		(void)fcntl(3, F_CLOSEM, 0);
 #else
 		for (fd = 3; fd < getdtablesize(); ++fd)
 			(void)close(fd);
 #endif
 		(void)execve(pam_ssh_agent,
 		    (char **)__UNCONST(pam_ssh_agent_argv),
 		    (char **)__UNCONST(pam_ssh_agent_envp));
 done:
 		_exit(127);
+	}
 	/* parent */
 	close(agent_pipe[1]);
 	if ((f = fdopen(agent_pipe[0], "r")) == NULL)
 		return (PAM_SYSTEM_ERR);
 	pam_ssh_process_agent_output(pamh, f);
 	fclose(f);
 	return (PAM_SUCCESS);
+}
 /*
  * Adds previously stored keys to a running agent.
  */
 static int
 pam_ssh_add_keys_to_agent(pam_handle_t *pamh)
+{
 	AuthenticationConnection *ac;
 	const struct pam_ssh_key *psk;
 	const char **kfn;
 	char **envlist, **env;
 	int pam_err;
 	/* switch to PAM environment */
 	envlist = environ;
 	if ((environ = pam_getenvlist(pamh)) == NULL) {
 		openpam_log(PAM_LOG_DEBUG, "%s: cannot get envlist",
 		    __func__);
 		environ = envlist;
 		return (PAM_SYSTEM_ERR);
+	}
 	/* get a connection to the agent */
 	if ((ac = ssh_get_authentication_connection()) == NULL) {
 		openpam_log(PAM_LOG_DEBUG,
 		    "%s: cannot get authentication connection",
 		    __func__);
 		pam_err = PAM_SYSTEM_ERR;
 		goto end;
+	}
 	/* look for keys to add to it */
 	for (kfn = pam_ssh_keyfiles; *kfn != NULL; ++kfn) {
 		const void *vp;
 		pam_err = pam_get_data(pamh, *kfn, &vp);
 		psk = vp;
 		if (pam_err == PAM_SUCCESS && psk != NULL) {
-			if (ssh_add_identity_constrained(ac, psk->key, psk->comment, 0, 0))
+			if (ssh_add_identity(ac, psk->key, psk->comment))
 				openpam_log(PAM_LOG_DEBUG,
 				    "added %s to ssh agent", psk->comment);
 			else
 				openpam_log(PAM_LOG_DEBUG, "failed "
 				    "to add %s to ssh agent", psk->comment);
 			/* we won't need the key again, so wipe it */
 			pam_set_data(pamh, *kfn, NULL, NULL);
+		}
+	}
 	pam_err = PAM_SUCCESS;
  end:
 	/* disconnect from agent */
 	if (ac != NULL)
 		ssh_close_authentication_connection(ac);
 	/* switch back to original environment */
 	for (env = environ; *env != NULL; ++env)
 		free(*env);
 	free(environ);
 	environ = envlist;
 	return (pam_err);
+}
 PAM_EXTERN int
 pam_sm_open_session(pam_handle_t *pamh, int flags __unused,
     int argc __unused, const char *argv[] __unused)
+{
 	struct passwd *pwd, pwres;
 	const char *user;
 	const void *data;
 	int pam_err = PAM_SUCCESS;
 	char pwbuf[1024];
 	/* no keys, no work */
 	if (pam_get_data(pamh, pam_ssh_have_keys, &data) != PAM_SUCCESS &&
 	    openpam_get_option(pamh, "want_agent") == NULL)
 		return (PAM_SUCCESS);
 	/* switch to user credentials */
 	pam_err = pam_get_user(pamh, &user, NULL);
 	if (pam_err != PAM_SUCCESS)
 		return (pam_err);
 	if (getpwnam_r(user, &pwres, pwbuf, sizeof(pwbuf), &pwd) != 0 ||
 	    pwd == NULL)
 		return (PAM_USER_UNKNOWN);
 	/* start the agent */
 	pam_err = pam_ssh_start_agent(pamh, pwd);
 	if (pam_err != PAM_SUCCESS)
 		return pam_err;
 	pam_err = openpam_borrow_cred(pamh, pwd);
 	if (pam_err != PAM_SUCCESS)
 		return pam_err;
 	/* we have an agent, see if we can add any keys to it */
 	pam_err = pam_ssh_add_keys_to_agent(pamh);
 	if (pam_err != PAM_SUCCESS) {
 		/* XXX ignore failures */
 		openpam_log(PAM_LOG_DEBUG, "failed adding keys to ssh agent");
 		pam_err = PAM_SUCCESS;
+	}
 	openpam_restore_cred(pamh);
 	return pam_err;
+}
 PAM_EXTERN int
 pam_sm_close_session(pam_handle_t *pamh, int flags __unused,
     int argc __unused, const char *argv[] __unused)
+{
 	const char *ssh_agent_pid;
 	char *end;
 	int status;
 	pid_t pid;
 	if ((ssh_agent_pid = pam_getenv(pamh, "SSH_AGENT_PID")) == NULL) {
 		openpam_log(PAM_LOG_DEBUG, "no ssh agent");
 		return (PAM_SUCCESS);
+	}
 	pid = (pid_t)strtol(ssh_agent_pid, &end, 10);
 	if (*ssh_agent_pid == '\0' || *end != '\0') {
 		openpam_log(PAM_LOG_DEBUG, "invalid ssh agent pid");
 		return (PAM_SESSION_ERR);
+	}
 	openpam_log(PAM_LOG_DEBUG, "killing ssh agent %d", (int)pid);
 	if (kill(pid, SIGTERM) == -1 ||
 	    (waitpid(pid, &status, 0) == -1 && errno != ECHILD))
 		return (PAM_SYSTEM_ERR);
 	return (PAM_SUCCESS);
+}
 PAM_MODULE_ENTRY("pam_ssh");