* 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. All advertising materials mentioning features or use of this software
- * must display the following acknowledgement:
- * This product includes software developed by Markus Friedl.
- * 4. 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 ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
#include "includes.h"
#ifdef USE_PAM
-#include "ssh.h"
#include "xmalloc.h"
+#include "log.h"
+#include "auth.h"
+#include "auth-options.h"
+#include "auth-pam.h"
#include "servconf.h"
+#include "canohost.h"
+#include "readpass.h"
+
+extern char *__progname;
+
+extern int use_privsep;
RCSID("$Id$");
#define NEW_AUTHTOK_MSG \
- "Warning: You password has expired, please change it now"
+ "Warning: Your password has expired, please change it now."
+#define NEW_AUTHTOK_MSG_PRIVSEP \
+ "Your password has expired, the session cannot proceed."
-/* Callbacks */
-static int pamconv(int num_msg, const struct pam_message **msg,
- struct pam_response **resp, void *appdata_ptr);
-void pam_cleanup_proc(void *context);
-void pam_msg_cat(const char *msg);
+static int do_pam_conversation(int num_msg, const struct pam_message **msg,
+ struct pam_response **resp, void *appdata_ptr);
/* module-local variables */
static struct pam_conv conv = {
- pamconv,
+ (int (*)())do_pam_conversation,
NULL
};
-static struct pam_handle_t *pamh = NULL;
-static const char *pampasswd = NULL;
-static char *pam_msg = NULL;
+static char *__pam_msg = NULL;
+static pam_handle_t *__pamh = NULL;
+static const char *__pampasswd = NULL;
+
+/* states for do_pam_conversation() */
+enum { INITIAL_LOGIN, OTHER } pamstate = INITIAL_LOGIN;
+/* remember whether pam_acct_mgmt() returned PAM_NEW_AUTHTOK_REQD */
+static int password_change_required = 0;
+/* remember whether the last pam_authenticate() succeeded or not */
+static int was_authenticated = 0;
+
+/* Remember what has been initialised */
+static int session_opened = 0;
+static int creds_set = 0;
+
+/* accessor which allows us to switch conversation structs according to
+ * the authentication method being used */
+void do_pam_set_conv(struct pam_conv *conv)
+{
+ pam_set_item(__pamh, PAM_CONV, conv);
+}
+
+/* start an authentication run */
+int do_pam_authenticate(int flags)
+{
+ int retval = pam_authenticate(__pamh, flags);
+ was_authenticated = (retval == PAM_SUCCESS);
+ return retval;
+}
-/* PAM conversation function. This is really a kludge to get the password */
-/* into PAM and to pick up any messages generated by PAM into pamconv_msg */
-static int pamconv(int num_msg, const struct pam_message **msg,
+/*
+ * PAM conversation function.
+ * There are two states this can run in.
+ *
+ * INITIAL_LOGIN mode simply feeds the password from the client into
+ * PAM in response to PAM_PROMPT_ECHO_OFF, and collects output
+ * messages with into __pam_msg. This is used during initial
+ * authentication to bypass the normal PAM password prompt.
+ *
+ * OTHER mode handles PAM_PROMPT_ECHO_OFF with read_passphrase()
+ * and outputs messages to stderr. This mode is used if pam_chauthtok()
+ * is called to update expired passwords.
+ */
+static int do_pam_conversation(int num_msg, const struct pam_message **msg,
struct pam_response **resp, void *appdata_ptr)
{
struct pam_response *reply;
int count;
+ char buf[1024];
/* PAM will free this later */
- reply = malloc(num_msg * sizeof(*reply));
- if (reply == NULL)
- return PAM_CONV_ERR;
-
- for(count = 0; count < num_msg; count++) {
- switch (msg[count]->msg_style) {
+ reply = xmalloc(num_msg * sizeof(*reply));
+
+ for (count = 0; count < num_msg; count++) {
+ if (pamstate == INITIAL_LOGIN) {
+ /*
+ * We can't use stdio yet, queue messages for
+ * printing later
+ */
+ switch(PAM_MSG_MEMBER(msg, count, msg_style)) {
+ case PAM_PROMPT_ECHO_ON:
+ xfree(reply);
+ return PAM_CONV_ERR;
case PAM_PROMPT_ECHO_OFF:
- if (pampasswd == NULL) {
- free(reply);
+ if (__pampasswd == NULL) {
+ xfree(reply);
return PAM_CONV_ERR;
}
+ reply[count].resp = xstrdup(__pampasswd);
reply[count].resp_retcode = PAM_SUCCESS;
- reply[count].resp = xstrdup(pampasswd);
break;
+ case PAM_ERROR_MSG:
case PAM_TEXT_INFO:
+ if (PAM_MSG_MEMBER(msg, count, msg) != NULL) {
+ message_cat(&__pam_msg,
+ PAM_MSG_MEMBER(msg, count, msg));
+ }
+ reply[count].resp = xstrdup("");
+ reply[count].resp_retcode = PAM_SUCCESS;
+ break;
+ default:
+ xfree(reply);
+ return PAM_CONV_ERR;
+ }
+ } else {
+ /*
+ * stdio is connected, so interact directly
+ */
+ switch(PAM_MSG_MEMBER(msg, count, msg_style)) {
+ case PAM_PROMPT_ECHO_ON:
+ fputs(PAM_MSG_MEMBER(msg, count, msg), stderr);
+ fgets(buf, sizeof(buf), stdin);
+ reply[count].resp = xstrdup(buf);
reply[count].resp_retcode = PAM_SUCCESS;
+ break;
+ case PAM_PROMPT_ECHO_OFF:
+ reply[count].resp =
+ read_passphrase(PAM_MSG_MEMBER(msg, count,
+ msg), RP_ALLOW_STDIN);
+ reply[count].resp_retcode = PAM_SUCCESS;
+ break;
+ case PAM_ERROR_MSG:
+ case PAM_TEXT_INFO:
+ if (PAM_MSG_MEMBER(msg, count, msg) != NULL)
+ fprintf(stderr, "%s\n",
+ PAM_MSG_MEMBER(msg, count, msg));
reply[count].resp = xstrdup("");
-
- if (msg[count]->msg != NULL)
- pam_msg_cat(msg[count]->msg);
-
+ reply[count].resp_retcode = PAM_SUCCESS;
break;
default:
- free(reply);
+ xfree(reply);
return PAM_CONV_ERR;
+ }
}
}
}
/* Called at exit to cleanly shutdown PAM */
-void pam_cleanup_proc(void *context)
+void do_pam_cleanup_proc(void *context)
{
- int pam_retval;
+ int pam_retval = PAM_SUCCESS;
- if (pamh != NULL)
- {
- pam_retval = pam_close_session((pam_handle_t *)pamh, 0);
- if (pam_retval != PAM_SUCCESS) {
- log("Cannot close PAM session: %.200s",
- PAM_STRERROR((pam_handle_t *)pamh, pam_retval));
- }
+ if (__pamh && session_opened) {
+ pam_retval = pam_close_session(__pamh, 0);
+ if (pam_retval != PAM_SUCCESS)
+ logit("Cannot close PAM session[%d]: %.200s",
+ pam_retval, PAM_STRERROR(__pamh, pam_retval));
+ }
- pam_retval = pam_setcred((pam_handle_t *)pamh, PAM_DELETE_CRED);
- if (pam_retval != PAM_SUCCESS) {
- log("Cannot delete credentials: %.200s",
- PAM_STRERROR((pam_handle_t *)pamh, pam_retval));
- }
+ if (__pamh && creds_set) {
+ pam_retval = pam_setcred(__pamh, PAM_DELETE_CRED);
+ if (pam_retval != PAM_SUCCESS)
+ debug("Cannot delete credentials[%d]: %.200s",
+ pam_retval, PAM_STRERROR(__pamh, pam_retval));
+ }
- pam_retval = pam_end((pam_handle_t *)pamh, pam_retval);
- if (pam_retval != PAM_SUCCESS) {
- log("Cannot release PAM authentication: %.200s",
- PAM_STRERROR((pam_handle_t *)pamh, pam_retval));
- }
+ if (__pamh) {
+ pam_retval = pam_end(__pamh, pam_retval);
+ if (pam_retval != PAM_SUCCESS)
+ logit("Cannot release PAM authentication[%d]: %.200s",
+ pam_retval, PAM_STRERROR(__pamh, pam_retval));
}
}
-/* Attempt password authentation using PAM */
-int auth_pam_password(struct passwd *pw, const char *password)
+/* Attempt password authentication using PAM */
+int auth_pam_password(Authctxt *authctxt, const char *password)
{
extern ServerOptions options;
int pam_retval;
+ struct passwd *pw = authctxt->pw;
- /* deny if no user. */
- if (pw == NULL)
- return 0;
- if (pw->pw_uid == 0 && options.permit_root_login == 2)
- return 0;
- if (*password == '\0' && options.permit_empty_passwd == 0)
- return 0;
+ do_pam_set_conv(&conv);
- pampasswd = password;
-
- pam_retval = pam_authenticate((pam_handle_t *)pamh, 0);
- if (pam_retval == PAM_SUCCESS) {
- debug("PAM Password authentication accepted for user \"%.100s\"",
- pw->pw_name);
+ __pampasswd = password;
+
+ pamstate = INITIAL_LOGIN;
+ pam_retval = do_pam_authenticate(
+ options.permit_empty_passwd == 0 ? PAM_DISALLOW_NULL_AUTHTOK : 0);
+ if (pam_retval == PAM_SUCCESS && pw) {
+ debug("PAM password authentication accepted for "
+ "%.100s", pw->pw_name);
return 1;
} else {
- debug("PAM Password authentication for \"%.100s\" failed: %s",
- pw->pw_name, PAM_STRERROR((pam_handle_t *)pamh, pam_retval));
+ debug("PAM password authentication failed for "
+ "%.100s: %s", pw ? pw->pw_name : "an illegal user",
+ PAM_STRERROR(__pamh, pam_retval));
return 0;
}
}
int do_pam_account(char *username, char *remote_user)
{
int pam_retval;
-
- debug("PAM setting rhost to \"%.200s\"", get_canonical_hostname());
- pam_retval = pam_set_item((pam_handle_t *)pamh, PAM_RHOST,
- get_canonical_hostname());
- if (pam_retval != PAM_SUCCESS) {
- fatal("PAM set rhost failed: %.200s",
- PAM_STRERROR((pam_handle_t *)pamh, pam_retval));
- }
- if (remote_user != NULL) {
+ do_pam_set_conv(&conv);
+
+ if (remote_user) {
debug("PAM setting ruser to \"%.200s\"", remote_user);
- pam_retval = pam_set_item((pam_handle_t *)pamh, PAM_RUSER, remote_user);
- if (pam_retval != PAM_SUCCESS) {
- fatal("PAM set ruser failed: %.200s",
- PAM_STRERROR((pam_handle_t *)pamh, pam_retval));
- }
+ pam_retval = pam_set_item(__pamh, PAM_RUSER, remote_user);
+ if (pam_retval != PAM_SUCCESS)
+ fatal("PAM set ruser failed[%d]: %.200s", pam_retval,
+ PAM_STRERROR(__pamh, pam_retval));
}
- pam_retval = pam_acct_mgmt((pam_handle_t *)pamh, 0);
+ pam_retval = pam_acct_mgmt(__pamh, 0);
+ debug2("pam_acct_mgmt() = %d", pam_retval);
switch (pam_retval) {
case PAM_SUCCESS:
/* This is what we want */
break;
+#if 0
case PAM_NEW_AUTHTOK_REQD:
- pam_msg_cat(NEW_AUTHTOK_MSG);
+ message_cat(&__pam_msg, use_privsep ?
+ NEW_AUTHTOK_MSG_PRIVSEP : NEW_AUTHTOK_MSG);
+ /* flag that password change is necessary */
+ password_change_required = 1;
+ /* disallow other functionality for now */
+ no_port_forwarding_flag |= 2;
+ no_agent_forwarding_flag |= 2;
+ no_x11_forwarding_flag |= 2;
break;
+#endif
default:
- log("PAM rejected by account configuration: %.200s",
- PAM_STRERROR((pam_handle_t *)pamh, pam_retval));
+ logit("PAM rejected by account configuration[%d]: "
+ "%.200s", pam_retval, PAM_STRERROR(__pamh,
+ pam_retval));
return(0);
}
-
+
return(1);
}
{
int pam_retval;
+ do_pam_set_conv(&conv);
+
if (ttyname != NULL) {
debug("PAM setting tty to \"%.200s\"", ttyname);
- pam_retval = pam_set_item((pam_handle_t *)pamh, PAM_TTY, ttyname);
- if (pam_retval != PAM_SUCCESS) {
- fatal("PAM set tty failed: %.200s",
- PAM_STRERROR((pam_handle_t *)pamh, pam_retval));
- }
+ pam_retval = pam_set_item(__pamh, PAM_TTY, ttyname);
+ if (pam_retval != PAM_SUCCESS)
+ fatal("PAM set tty failed[%d]: %.200s",
+ pam_retval, PAM_STRERROR(__pamh, pam_retval));
}
- pam_retval = pam_open_session((pam_handle_t *)pamh, 0);
- if (pam_retval != PAM_SUCCESS) {
- fatal("PAM session setup failed: %.200s",
- PAM_STRERROR((pam_handle_t *)pamh, pam_retval));
- }
+ pam_retval = pam_open_session(__pamh, 0);
+ if (pam_retval != PAM_SUCCESS)
+ fatal("PAM session setup failed[%d]: %.200s",
+ pam_retval, PAM_STRERROR(__pamh, pam_retval));
+
+ session_opened = 1;
}
-/* Set PAM credentials */
-void do_pam_setcred()
+/* Set PAM credentials */
+void do_pam_setcred(int init)
{
int pam_retval;
-
+
+ if (__pamh == NULL)
+ return;
+
+ do_pam_set_conv(&conv);
+
debug("PAM establishing creds");
- pam_retval = pam_setcred((pam_handle_t *)pamh, PAM_ESTABLISH_CRED);
+ pam_retval = pam_setcred(__pamh,
+ init ? PAM_ESTABLISH_CRED : PAM_REINITIALIZE_CRED);
if (pam_retval != PAM_SUCCESS) {
- fatal("PAM setcred failed: %.200s",
- PAM_STRERROR((pam_handle_t *)pamh, pam_retval));
+ if (was_authenticated)
+ fatal("PAM setcred failed[%d]: %.200s",
+ pam_retval, PAM_STRERROR(__pamh, pam_retval));
+ else
+ debug("PAM setcred failed[%d]: %.200s",
+ pam_retval, PAM_STRERROR(__pamh, pam_retval));
+ } else
+ creds_set = 1;
+}
+
+/* accessor function for file scope static variable */
+int is_pam_password_change_required(void)
+{
+ return password_change_required;
+}
+
+/*
+ * Have user change authentication token if pam_acct_mgmt() indicated
+ * it was expired. This needs to be called after an interactive
+ * session is established and the user's pty is connected to
+ * stdin/stdout/stderr.
+ */
+void do_pam_chauthtok(void)
+{
+ int pam_retval;
+
+ do_pam_set_conv(&conv);
+
+ if (password_change_required) {
+ if (use_privsep)
+ fatal("Password changing is currently unsupported"
+ " with privilege separation");
+ pamstate = OTHER;
+ pam_retval = pam_chauthtok(__pamh, PAM_CHANGE_EXPIRED_AUTHTOK);
+ if (pam_retval != PAM_SUCCESS)
+ fatal("PAM pam_chauthtok failed[%d]: %.200s",
+ pam_retval, PAM_STRERROR(__pamh, pam_retval));
+#if 0
+ /* XXX: This would need to be done in the parent process,
+ * but there's currently no way to pass such request. */
+ no_port_forwarding_flag &= ~2;
+ no_agent_forwarding_flag &= ~2;
+ no_x11_forwarding_flag &= ~2;
+ if (!no_port_forwarding_flag && options.allow_tcp_forwarding)
+ channel_permit_all_opens();
+#endif
}
}
/* Cleanly shutdown PAM */
void finish_pam(void)
{
- pam_cleanup_proc(NULL);
- fatal_remove_cleanup(&pam_cleanup_proc, NULL);
+ do_pam_cleanup_proc(NULL);
+ fatal_remove_cleanup(&do_pam_cleanup_proc, NULL);
}
/* Start PAM authentication for specified account */
-void start_pam(struct passwd *pw)
+void start_pam(const char *user)
{
int pam_retval;
-
- debug("Starting up PAM with username \"%.200s\"", pw->pw_name);
-
- pam_retval = pam_start(SSHD_PAM_SERVICE, pw->pw_name, &conv,
- (pam_handle_t**)&pamh);
-
- if (pam_retval != PAM_SUCCESS) {
- fatal("PAM initialisation failed: %.200s",
- PAM_STRERROR((pam_handle_t *)pamh, pam_retval));
- }
-
- fatal_add_cleanup(&pam_cleanup_proc, NULL);
+ extern ServerOptions options;
+ extern u_int utmp_len;
+ const char *rhost;
+
+ debug("Starting up PAM with username \"%.200s\"", user);
+
+ pam_retval = pam_start(SSHD_PAM_SERVICE, user, &conv, &__pamh);
+
+ if (pam_retval != PAM_SUCCESS)
+ fatal("PAM initialisation failed[%d]: %.200s",
+ pam_retval, PAM_STRERROR(__pamh, pam_retval));
+
+ rhost = get_remote_name_or_ip(utmp_len, options.verify_reverse_mapping);
+ debug("PAM setting rhost to \"%.200s\"", rhost);
+
+ pam_retval = pam_set_item(__pamh, PAM_RHOST, rhost);
+ if (pam_retval != PAM_SUCCESS)
+ fatal("PAM set rhost failed[%d]: %.200s", pam_retval,
+ PAM_STRERROR(__pamh, pam_retval));
+#ifdef PAM_TTY_KLUDGE
+ /*
+ * Some PAM modules (e.g. pam_time) require a TTY to operate,
+ * and will fail in various stupid ways if they don't get one.
+ * sshd doesn't set the tty until too late in the auth process and may
+ * not even need one (for tty-less connections)
+ * Kludge: Set a fake PAM_TTY
+ */
+ pam_retval = pam_set_item(__pamh, PAM_TTY, "NODEVssh");
+ if (pam_retval != PAM_SUCCESS)
+ fatal("PAM set tty failed[%d]: %.200s",
+ pam_retval, PAM_STRERROR(__pamh, pam_retval));
+#endif /* PAM_TTY_KLUDGE */
+
+ fatal_add_cleanup(&do_pam_cleanup_proc, NULL);
}
-/* Return list of PAM enviornment strings */
+/* Return list of PAM environment strings */
char **fetch_pam_environment(void)
{
#ifdef HAVE_PAM_GETENVLIST
- return(pam_getenvlist((pam_handle_t *)pamh));
+ return(pam_getenvlist(__pamh));
#else /* HAVE_PAM_GETENVLIST */
return(NULL);
#endif /* HAVE_PAM_GETENVLIST */
}
+void free_pam_environment(char **env)
+{
+ int i;
+
+ if (env != NULL) {
+ for (i = 0; env[i] != NULL; i++)
+ xfree(env[i]);
+ }
+}
+
/* Print any messages that have been generated during authentication */
/* or account checking to stderr */
void print_pam_messages(void)
{
- if (pam_msg != NULL)
- fprintf(stderr, pam_msg);
+ if (__pam_msg != NULL)
+ fputs(__pam_msg, stderr);
}
-/* Append a message to the PAM message buffer */
-void pam_msg_cat(const char *msg)
+/* Append a message to buffer */
+void message_cat(char **p, const char *a)
{
- char *p;
- size_t new_msg_len;
- size_t pam_msg_len;
-
- new_msg_len = strlen(msg);
-
- if (pam_msg) {
- pam_msg_len = strlen(pam_msg);
- pam_msg = xrealloc(pam_msg, new_msg_len + pam_msg_len + 2);
- p = pam_msg + pam_msg_len;
- } else {
- pam_msg = p = xmalloc(new_msg_len + 2);
- }
+ char *cp;
+ size_t new_len;
+
+ new_len = strlen(a);
+
+ if (*p) {
+ size_t len = strlen(*p);
+
+ *p = xrealloc(*p, new_len + len + 2);
+ cp = *p + len;
+ } else
+ *p = cp = xmalloc(new_len + 2);
- memcpy(p, msg, new_msg_len);
- p[new_msg_len] = '\n';
- p[new_msg_len + 1] = '\0';
+ memcpy(cp, a, new_len);
+ cp[new_len] = '\n';
+ cp[new_len + 1] = '\0';
}
#endif /* USE_PAM */
andersk / openssh.git / blobdiff