X-Git-Url: http://andersk.mit.edu/gitweb/openssh.git/blobdiff_plain/ad55cd035c604a3aa5f76a1f52b9f1a153b44790..ad2e1857ead440bc890368595899b6b51f1fe9bb:/auth-pam.c diff --git a/auth-pam.c b/auth-pam.c index 19187163..4b4c2f9d 100644 --- a/auth-pam.c +++ b/auth-pam.c @@ -27,33 +27,57 @@ #ifdef USE_PAM #include "ssh.h" #include "xmalloc.h" +#include "log.h" +#include "auth.h" +#include "auth-pam.h" #include "servconf.h" +#include "canohost.h" +#include "readpass.h" + +extern char *__progname; RCSID("$Id$"); #define NEW_AUTHTOK_MSG \ "Warning: Your password has expired, please change it now" -/* 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, + do_pam_conversation, NULL }; -static 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 pamconv() */ -typedef enum { INITIAL_LOGIN, OTHER } pamstates; -static pamstates pamstate = INITIAL_LOGIN; +/* states for do_pam_conversation() */ +enum { INITIAL_LOGIN, OTHER } pamstate = INITIAL_LOGIN; /* remember whether pam_acct_mgmt() returned PAM_NEWAUTHTOK_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. @@ -61,14 +85,14 @@ static int password_change_required = 0; * * INITIAL_LOGIN mode simply feeds the password from the client into * PAM in response to PAM_PROMPT_ECHO_OFF, and collects output - * messages with pam_msg_cat(). This is used during initial + * 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(prompt, 1) + * 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 pamconv(int num_msg, const struct pam_message **msg, +static int do_pam_conversation(int num_msg, const struct pam_message **msg, struct pam_response **resp, void *appdata_ptr) { struct pam_response *reply; @@ -78,43 +102,68 @@ static int pamconv(int num_msg, const struct pam_message **msg, /* PAM will free this later */ reply = malloc(num_msg * sizeof(*reply)); if (reply == NULL) - return PAM_CONV_ERR; + return PAM_CONV_ERR; for (count = 0; count < num_msg; count++) { - switch ((*msg)[count].msg_style) { + 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: - fputs((*msg)[count].msg, stderr); + free(reply); + return PAM_CONV_ERR; + case PAM_PROMPT_ECHO_OFF: + if (__pampasswd == NULL) { + free(reply); + return PAM_CONV_ERR; + } + reply[count].resp = xstrdup(__pampasswd); + reply[count].resp_retcode = PAM_SUCCESS; + break; + case PAM_ERROR_MSG: + case PAM_TEXT_INFO: + if ((*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: + free(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: - if (pamstate == INITIAL_LOGIN) { - if (pampasswd == NULL) { - free(reply); - return PAM_CONV_ERR; - } - reply[count].resp = xstrdup(pampasswd); - } else - reply[count].resp = xstrdup(read_passphrase((*msg)[count].msg, 1)); + 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 ((*msg)[count].msg != NULL) { - if (pamstate == INITIAL_LOGIN) - pam_msg_cat((*msg)[count].msg); - else { - fputs((*msg)[count].msg, stderr); - fputs("\n", stderr); - } - } + if ((*msg)[count].msg != NULL) + fprintf(stderr, "%s\n", + PAM_MSG_MEMBER(msg, count, msg)); reply[count].resp = xstrdup(""); reply[count].resp_retcode = PAM_SUCCESS; break; default: free(reply); return PAM_CONV_ERR; + } } } @@ -124,57 +173,62 @@ static int pamconv(int num_msg, const struct pam_message **msg, } /* 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(pamh, 0); - if (pam_retval != PAM_SUCCESS) { - log("Cannot close PAM session: %.200s", - PAM_STRERROR(pamh, pam_retval)); - } + if (__pamh && session_opened) { + pam_retval = pam_close_session(__pamh, 0); + if (pam_retval != PAM_SUCCESS) + log("Cannot close PAM session[%d]: %.200s", + pam_retval, PAM_STRERROR(__pamh, pam_retval)); + } - pam_retval = pam_setcred(pamh, PAM_DELETE_CRED); - if (pam_retval != PAM_SUCCESS) { - debug("Cannot delete credentials: %.200s", - PAM_STRERROR(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(pamh, pam_retval); - if (pam_retval != PAM_SUCCESS) { - log("Cannot release PAM authentication: %.200s", - PAM_STRERROR(pamh, pam_retval)); - } + if (__pamh) { + pam_retval = pam_end(__pamh, pam_retval); + if (pam_retval != PAM_SUCCESS) + log("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) +int auth_pam_password(Authctxt *authctxt, const char *password) { extern ServerOptions options; int pam_retval; + struct passwd *pw = authctxt->pw; + + do_pam_set_conv(&conv); /* deny if no user. */ if (pw == NULL) return 0; - if (pw->pw_uid == 0 && options.permit_root_login == 2) + if (pw->pw_uid == 0 && options.permit_root_login == PERMIT_NO_PASSWD) return 0; if (*password == '\0' && options.permit_empty_passwd == 0) return 0; - pampasswd = password; - + __pampasswd = password; + pamstate = INITIAL_LOGIN; - pam_retval = pam_authenticate(pamh, 0); + pam_retval = do_pam_authenticate( + options.permit_empty_passwd == 0 ? PAM_DISALLOW_NULL_AUTHTOK : 0); if (pam_retval == PAM_SUCCESS) { - debug("PAM Password authentication accepted for user \"%.100s\"", - pw->pw_name); + debug("PAM Password authentication accepted for " + "user \"%.100s\"", pw->pw_name); return 1; } else { - debug("PAM Password authentication for \"%.100s\" failed: %s", - pw->pw_name, PAM_STRERROR(pamh, pam_retval)); + debug("PAM Password authentication for \"%.100s\" " + "failed[%d]: %s", pw->pw_name, pam_retval, + PAM_STRERROR(__pamh, pam_retval)); return 0; } } @@ -183,40 +237,37 @@ int auth_pam_password(struct passwd *pw, const char *password) 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(pamh, PAM_RHOST, - get_canonical_hostname()); - if (pam_retval != PAM_SUCCESS) { - fatal("PAM set rhost failed: %.200s", - PAM_STRERROR(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(pamh, PAM_RUSER, remote_user); - if (pam_retval != PAM_SUCCESS) { - fatal("PAM set ruser failed: %.200s", - PAM_STRERROR(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(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, NEW_AUTHTOK_MSG); /* flag that password change is necessary */ password_change_required = 1; break; +#endif default: - log("PAM rejected by account configuration: %.200s", - PAM_STRERROR(pamh, pam_retval)); + log("PAM rejected by account configuration[%d]: " + "%.200s", pam_retval, PAM_STRERROR(__pamh, + pam_retval)); return(0); } - + return(1); } @@ -225,97 +276,127 @@ void do_pam_session(char *username, const char *ttyname) { int pam_retval; + do_pam_set_conv(&conv); + if (ttyname != NULL) { debug("PAM setting tty to \"%.200s\"", ttyname); - pam_retval = pam_set_item(pamh, PAM_TTY, ttyname); - if (pam_retval != PAM_SUCCESS) { - fatal("PAM set tty failed: %.200s", - PAM_STRERROR(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(pamh, 0); - if (pam_retval != PAM_SUCCESS) { - fatal("PAM session setup failed: %.200s", - PAM_STRERROR(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(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(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/stout/stderr. */ -void do_pam_chauthtok() +void do_pam_chauthtok(void) { int pam_retval; + do_pam_set_conv(&conv); + if (password_change_required) { pamstate = OTHER; - do { - pam_retval = pam_chauthtok(pamh, PAM_CHANGE_EXPIRED_AUTHTOK); - } while (pam_retval != PAM_SUCCESS); + 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)); } } /* 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; + extern ServerOptions options; + extern u_int utmp_len; + const char *rhost; - debug("Starting up PAM with username \"%.200s\"", pw->pw_name); + debug("Starting up PAM with username \"%.200s\"", user); - pam_retval = pam_start(SSHD_PAM_SERVICE, pw->pw_name, &conv, &pamh); + pam_retval = pam_start(SSHD_PAM_SERVICE, user, &conv, &__pamh); - if (pam_retval != PAM_SUCCESS) { - fatal("PAM initialisation failed: %.200s", - PAM_STRERROR(pamh, pam_retval)); - } + 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. + * 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 + * Kludge: Set a fake PAM_TTY */ - pam_retval = pam_set_item(pamh, PAM_TTY, "ssh"); - if (pam_retval != PAM_SUCCESS) { - fatal("PAM set tty failed: %.200s", - PAM_STRERROR(pamh, pam_retval)); - } + 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(&pam_cleanup_proc, NULL); + fatal_add_cleanup(&do_pam_cleanup_proc, NULL); } /* Return list of PAM enviornment strings */ char **fetch_pam_environment(void) { #ifdef HAVE_PAM_GETENVLIST - return(pam_getenvlist(pamh)); + return(pam_getenvlist(__pamh)); #else /* HAVE_PAM_GETENVLIST */ return(NULL); #endif /* HAVE_PAM_GETENVLIST */ @@ -325,30 +406,29 @@ char **fetch_pam_environment(void) /* or account checking to stderr */ void print_pam_messages(void) { - if (pam_msg != NULL) - fputs(pam_msg, stderr); + 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 */