Mercurial > dovecot > original-hg > dovecot-1.2
view src/auth/passdb-pam.c @ 3978:6f21ccb60df4 HEAD
If error message from PAM was over ~500 bytes, we crashed. Probably never
happened. Also use PIPE_BUF instead of hardcoded 512 bytes.
author | Timo Sirainen <tss@iki.fi> |
---|---|
date | Sun, 05 Feb 2006 09:24:37 +0200 |
parents | 3c10e68ceb7c |
children | 198ad9bf81d2 |
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/* Based on auth_pam.c from popa3d by Solar Designer <solar@openwall.com>. You're allowed to do whatever you like with this software (including re-distribution in source and/or binary form, with or without modification), provided that credit is given where it is due and any modified versions are marked as such. There's absolutely no warranty. */ #include "common.h" #ifdef PASSDB_PAM #include "buffer.h" #include "ioloop.h" #include "network.h" #include "passdb.h" #include "mycrypt.h" #include "safe-memset.h" #include <stdlib.h> #include <fcntl.h> #include <unistd.h> #include <sys/wait.h> #ifdef HAVE_SECURITY_PAM_APPL_H # include <security/pam_appl.h> #elif defined(HAVE_PAM_PAM_APPL_H) # include <pam/pam_appl.h> #endif #if !defined(_SECURITY_PAM_APPL_H) && !defined(LINUX_PAM) && !defined(_OPENPAM) /* Sun's PAM doesn't use const. we use a bit dirty hack to check it. Originally it was just __sun__ check, but HP/UX also uses Sun's PAM so I thought this might work better. */ # define linux_const #else # define linux_const const #endif typedef linux_const void *pam_item_t; #ifdef AUTH_PAM_USERPASS # include <security/pam_client.h> # ifndef PAM_BP_RCONTROL /* Linux-PAM prior to 0.74 */ # define PAM_BP_RCONTROL PAM_BP_CONTROL # define PAM_BP_WDATA PAM_BP_DATA # define PAM_BP_RDATA PAM_BP_DATA # endif # define USERPASS_AGENT_ID "userpass" # define USERPASS_AGENT_ID_LENGTH 8 # define USERPASS_USER_MASK 0x03 # define USERPASS_USER_REQUIRED 1 # define USERPASS_USER_KNOWN 2 # define USERPASS_USER_FIXED 3 #endif struct pam_passdb_module { struct passdb_module module; bool pam_session; const char *service_name, *pam_cache_key; struct timeout *to_wait; }; struct pam_auth_request { int fd; struct io *io; struct auth_request *request; verify_plain_callback_t *callback; }; struct pam_userpass { const char *user; const char *pass; }; static int pam_userpass_conv(int num_msg, linux_const struct pam_message **msg, struct pam_response **resp, void *appdata_ptr) { /* @UNSAFE */ struct pam_userpass *userpass = (struct pam_userpass *) appdata_ptr; #ifdef AUTH_PAM_USERPASS pamc_bp_t prompt; const char *input; char *output; char flags; size_t userlen, passlen; if (num_msg != 1 || msg[0]->msg_style != PAM_BINARY_PROMPT) return PAM_CONV_ERR; prompt = (pamc_bp_t)msg[0]->msg; input = PAM_BP_RDATA(prompt); if (PAM_BP_RCONTROL(prompt) != PAM_BPC_SELECT || strncmp(input, USERPASS_AGENT_ID "/", USERPASS_AGENT_ID_LENGTH + 1)) return PAM_CONV_ERR; flags = input[USERPASS_AGENT_ID_LENGTH + 1]; input += USERPASS_AGENT_ID_LENGTH + 1 + 1; if ((flags & USERPASS_USER_MASK) == USERPASS_USER_FIXED && strcmp(input, userpass->user)) return PAM_CONV_AGAIN; if (!(*resp = malloc(sizeof(struct pam_response)))) return PAM_CONV_ERR; userlen = strlen(userpass->user); passlen = strlen(userpass->pass); prompt = NULL; PAM_BP_RENEW(&prompt, PAM_BPC_DONE, userlen + 1 + passlen); output = PAM_BP_WDATA(prompt); memcpy(output, userpass->user, userlen + 1); memcpy(output + userlen + 1, userpass->pass, passlen); (*resp)[0].resp_retcode = 0; (*resp)[0].resp = (char *)prompt; #else char *string; int i; if (!(*resp = malloc(num_msg * sizeof(struct pam_response)))) return PAM_CONV_ERR; for (i = 0; i < num_msg; i++) { switch (msg[i]->msg_style) { case PAM_PROMPT_ECHO_ON: string = strdup(userpass->user); if (string == NULL) i_fatal_status(FATAL_OUTOFMEM, "Out of memory"); break; case PAM_PROMPT_ECHO_OFF: string = strdup(userpass->pass); if (string == NULL) i_fatal_status(FATAL_OUTOFMEM, "Out of memory"); break; case PAM_ERROR_MSG: case PAM_TEXT_INFO: string = NULL; break; default: while (--i >= 0) { if ((*resp)[i].resp == NULL) continue; safe_memset((*resp)[i].resp, 0, strlen((*resp)[i].resp)); free((*resp)[i].resp); (*resp)[i].resp = NULL; } free(*resp); *resp = NULL; return PAM_CONV_ERR; } (*resp)[i].resp_retcode = PAM_SUCCESS; (*resp)[i].resp = string; } #endif return PAM_SUCCESS; } static int pam_auth(struct auth_request *request, pam_handle_t *pamh, const char **error) { struct passdb_module *_module = request->passdb->passdb; struct pam_passdb_module *module = (struct pam_passdb_module *)_module; void *item; int status; *error = NULL; if ((status = pam_authenticate(pamh, 0)) != PAM_SUCCESS) { *error = t_strdup_printf("pam_authenticate() failed: %s", pam_strerror(pamh, status)); return status; } #ifdef HAVE_PAM_SETCRED if ((status = pam_setcred(pamh, PAM_ESTABLISH_CRED)) != PAM_SUCCESS) { *error = t_strdup_printf("pam_setcred() failed: %s", pam_strerror(pamh, status)); return status; } #endif if ((status = pam_acct_mgmt(pamh, 0)) != PAM_SUCCESS) { *error = t_strdup_printf("pam_acct_mgmt() failed: %s", pam_strerror(pamh, status)); return status; } if (module->pam_session) { if ((status = pam_open_session(pamh, 0)) != PAM_SUCCESS) { *error = t_strdup_printf( "pam_open_session() failed: %s", pam_strerror(pamh, status)); return status; } if ((status = pam_close_session(pamh, 0)) != PAM_SUCCESS) { *error = t_strdup_printf( "pam_close_session() failed: %s", pam_strerror(pamh, status)); return status; } } status = pam_get_item(pamh, PAM_USER, (linux_const void **)&item); if (status != PAM_SUCCESS) { *error = t_strdup_printf("pam_get_item() failed: %s", pam_strerror(pamh, status)); return status; } auth_request_set_field(request, "user", item, NULL); return PAM_SUCCESS; } static void pam_verify_plain_child(struct auth_request *request, const char *service, const char *password, int fd) { pam_handle_t *pamh; struct pam_userpass userpass; struct pam_conv conv; enum passdb_result result; int ret, status, status2; const char *str; size_t size; buffer_t *buf; conv.conv = pam_userpass_conv; conv.appdata_ptr = &userpass; userpass.user = request->user; userpass.pass = password; status = pam_start(service, request->user, &conv, &pamh); if (status != PAM_SUCCESS) { result = PASSDB_RESULT_INTERNAL_FAILURE; str = t_strdup_printf("pam_start() failed: %s", pam_strerror(pamh, status)); } else { const char *host = net_ip2addr(&request->remote_ip); if (host != NULL) pam_set_item(pamh, PAM_RHOST, host); status = pam_auth(request, pamh, &str); if ((status2 = pam_end(pamh, status)) == PAM_SUCCESS) { /* FIXME: check for PASSDB_RESULT_UNKNOWN_USER somehow? */ result = status == PAM_SUCCESS ? PASSDB_RESULT_OK : PASSDB_RESULT_PASSWORD_MISMATCH; } else { result = PASSDB_RESULT_INTERNAL_FAILURE; str = t_strdup_printf("pam_end() failed: %s", pam_strerror(pamh, status2)); } } buf = buffer_create_dynamic(pool_datastack_create(), 512); buffer_append(buf, &result, sizeof(result)); if (str != NULL) buffer_append(buf, str, strlen(str)); /* Don't send larger writes than what would block. truncated error message isn't that bad.. */ size = I_MIN(buf->used, PIPE_BUF); if ((ret = write(fd, buf->data, size)) != (int)size) { if (ret < 0) i_error("write() failed: %m"); else { i_error("write() failed: %d != %"PRIuSIZE_T, ret, buf->used); } } } static void pam_child_input(void *context) { struct pam_auth_request *request = context; struct auth_request *auth_request = request->request; enum passdb_result result; char buf[PIPE_BUF + 1]; ssize_t ret; /* POSIX guarantees that writing PIPE_BUF bytes or less to pipes is atomic. We rely on that. */ ret = read(request->fd, buf, sizeof(buf)-1); if (ret < 0) { auth_request_log_error(auth_request, "pam", "read() from child process failed: %m"); result = PASSDB_RESULT_INTERNAL_FAILURE; } else if (ret == 0) { /* it died */ auth_request_log_error(auth_request, "pam", "Child process died"); result = PASSDB_RESULT_INTERNAL_FAILURE; } else if ((size_t)ret < sizeof(result)) { auth_request_log_error(auth_request, "pam", "Child process returned only %d bytes", (int)ret); result = PASSDB_RESULT_INTERNAL_FAILURE; } else { memcpy(&result, buf, sizeof(result)); if ((size_t)ret > sizeof(result)) { /* error message included */ buf[ret] = '\0'; if (result == PASSDB_RESULT_INTERNAL_FAILURE) { auth_request_log_error(auth_request, "pam", "%s", buf + sizeof(result)); } else { auth_request_log_info(auth_request, "pam", "%s", buf + sizeof(result)); } } } if (close(request->fd) < 0) { auth_request_log_error(auth_request, "pam", "close(child input) failed: %m"); } request->callback(result, auth_request); auth_request_unref(&auth_request); io_remove(&request->io); i_free(request); } static void wait_timeout(void *context) { struct pam_passdb_module *module = context; int status; pid_t pid; /* FIXME: if we ever do some other kind of forking, this needs fixing */ while ((pid = waitpid(-1, &status, WNOHANG)) != 0) { if (pid == -1) { if (errno == ECHILD) timeout_remove(&module->to_wait); else if (errno != EINTR) i_error("waitpid() failed: %m"); return; } if (WIFSIGNALED(status)) { i_error("PAM: Child %s died with signal %d", dec2str(pid), WTERMSIG(status)); } } } static void pam_verify_plain(struct auth_request *request, const char *password, verify_plain_callback_t *callback) { struct passdb_module *_module = request->passdb->passdb; struct pam_passdb_module *module = (struct pam_passdb_module *)_module; struct pam_auth_request *pam_auth_request; const char *service; int fd[2]; pid_t pid; service = module->service_name != NULL ? module->service_name : request->service; if (pipe(fd) < 0) { auth_request_log_error(request, "pam", "pipe() failed: %m"); callback(PASSDB_RESULT_INTERNAL_FAILURE, request); return; } pid = fork(); if (pid == -1) { auth_request_log_error(request, "pam", "fork() failed: %m"); callback(PASSDB_RESULT_INTERNAL_FAILURE, request); (void)close(fd[0]); (void)close(fd[1]); return; } if (pid == 0) { (void)close(fd[0]); pam_verify_plain_child(request, service, password, fd[1]); _exit(0); } if (close(fd[1]) < 0) { auth_request_log_error(request, "pam", "close(fd[1]) failed: %m"); } auth_request_ref(request); pam_auth_request = i_new(struct pam_auth_request, 1); pam_auth_request->fd = fd[0]; pam_auth_request->request = request; pam_auth_request->callback = callback; pam_auth_request->io = io_add(fd[0], IO_READ, pam_child_input, pam_auth_request); if (module->to_wait == NULL) module->to_wait = timeout_add(1000, wait_timeout, module); } static struct passdb_module * pam_preinit(struct auth_passdb *auth_passdb, const char *args) { struct pam_passdb_module *module; const char *const *t_args; int i; module = p_new(auth_passdb->auth->pool, struct pam_passdb_module, 1); module->service_name = "dovecot"; t_push(); t_args = t_strsplit(args, " "); for(i = 0; t_args[i] != NULL; i++) { /* -session for backwards compatibility */ if (strcmp(t_args[i], "-session") == 0 || strcmp(t_args[i], "session=yes") == 0) module->pam_session = TRUE; else if (strncmp(t_args[i], "cache_key=", 10) == 0) { module->module.cache_key = p_strdup(auth_passdb->auth->pool, t_args[i] + 10); } else if (strcmp(t_args[i], "*") == 0) { module->service_name = NULL; } else if (t_args[i+1] == NULL) { if (*t_args[i] != '\0') { module->service_name = p_strdup(auth_passdb->auth->pool, t_args[i]); } } else { i_fatal("Unexpected PAM parameter: %s", t_args[i]); } } t_pop(); return &module->module; } static void pam_deinit(struct passdb_module *_module) { struct pam_passdb_module *module = (struct pam_passdb_module *)_module; if (module->to_wait != NULL) timeout_remove(&module->to_wait); } struct passdb_module_interface passdb_pam = { "pam", pam_preinit, NULL, pam_deinit, pam_verify_plain, NULL }; #endif