diff options
| -rw-r--r-- | modules/pam_motd/pam_motd.c | 97 |
1 files changed, 75 insertions, 22 deletions
diff --git a/modules/pam_motd/pam_motd.c b/modules/pam_motd/pam_motd.c index 46f4fe61..a4fd0e59 100644 --- a/modules/pam_motd/pam_motd.c +++ b/modules/pam_motd/pam_motd.c @@ -282,6 +282,72 @@ static void try_to_display_directories_with_overrides(pam_handle_t *pamh, _pam_drop(dirscans); } +static int drop_privileges(pam_handle_t *pamh, struct pam_modutil_privs *privs) +{ + struct passwd *pw; + const char *username; + int retval; + + retval = pam_get_user(pamh, &username, "key user"); + + if (retval == PAM_SUCCESS) { + pw = pam_modutil_getpwnam (pamh, username); + } else { + return PAM_SESSION_ERR; + } + + if (pw == NULL || pam_modutil_drop_priv(pamh, privs, pw)) { + return PAM_SESSION_ERR; + } + + return PAM_SUCCESS; +} + +static int try_to_display(pam_handle_t *pamh, char **motd_path_split, + unsigned int num_motd_paths, + char **motd_dir_path_split, + unsigned int num_motd_dir_paths, int report_missing) +{ + PAM_MODUTIL_DEF_PRIVS(privs); + + if (drop_privileges(pamh, &privs) != PAM_SUCCESS) { + pam_syslog(pamh, LOG_ERR, "Unable to drop privileges"); + return PAM_SESSION_ERR; + } + + if (motd_path_split != NULL) { + unsigned int i; + + for (i = 0; i < num_motd_paths; i++) { + int fd = open(motd_path_split[i], O_RDONLY, 0); + + if (fd >= 0) { + try_to_display_fd(pamh, fd); + close(fd); + + /* We found and displayed a file, + * move onto next filename. + */ + break; + } + } + } + + if (motd_dir_path_split != NULL) { + try_to_display_directories_with_overrides(pamh, + motd_dir_path_split, + num_motd_dir_paths, + report_missing); + } + + if (pam_modutil_regain_priv(pamh, &privs)) { + pam_syslog(pamh, LOG_ERR, "Unable to regain privileges"); + return PAM_SESSION_ERR; + } + + return PAM_SUCCESS; +} + int pam_sm_open_session(pam_handle_t *pamh, int flags, int argc, const char **argv) { @@ -358,25 +424,9 @@ int pam_sm_open_session(pam_handle_t *pamh, int flags, } } - if (motd_path_split != NULL) { - unsigned int i; - - for (i = 0; i < num_motd_paths; i++) { - int fd = open(motd_path_split[i], O_RDONLY, 0); - - if (fd >= 0) { - try_to_display_fd(pamh, fd); - close(fd); - - /* We found and displayed a file, move onto next filename. */ - break; - } - } - } - - if (motd_dir_path_split != NULL) - try_to_display_directories_with_overrides(pamh, motd_dir_path_split, - num_motd_dir_paths, report_missing); + retval = try_to_display(pamh, motd_path_split, num_motd_paths, + motd_dir_path_split, num_motd_dir_paths, + report_missing); out: _pam_drop(motd_path_copy); @@ -384,9 +434,12 @@ int pam_sm_open_session(pam_handle_t *pamh, int flags, _pam_drop(motd_dir_path_copy); _pam_drop(motd_dir_path_split); - retval = pam_putenv(pamh, "MOTD_SHOWN=pam"); - - return retval == PAM_SUCCESS ? PAM_IGNORE : retval; + if (retval == PAM_SUCCESS) { + retval = pam_putenv(pamh, "MOTD_SHOWN=pam"); + return retval == PAM_SUCCESS ? PAM_IGNORE : retval; + } else { + return retval; + } } /* end of module definition */ |