aboutsummaryrefslogtreecommitdiff
path: root/modules/pam_xauth/pam_xauth.c
diff options
context:
space:
mode:
Diffstat (limited to 'modules/pam_xauth/pam_xauth.c')
-rw-r--r--modules/pam_xauth/pam_xauth.c641
1 files changed, 0 insertions, 641 deletions
diff --git a/modules/pam_xauth/pam_xauth.c b/modules/pam_xauth/pam_xauth.c
deleted file mode 100644
index 700edbd3..00000000
--- a/modules/pam_xauth/pam_xauth.c
+++ /dev/null
@@ -1,641 +0,0 @@
-/*
- * Copyright 2001-2003 Red Hat, Inc.
- *
- * 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, and the entire permission notice in its entirety,
- * including the disclaimer of warranties.
- * 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.
- *
- * ALTERNATIVELY, this product may be distributed under the terms of
- * the GNU Public License, in which case the provisions of the GPL are
- * required INSTEAD OF the above restrictions. (This clause is
- * necessary due to a potential bad interaction between the GPL and
- * the restrictions contained in a BSD-style copyright.)
- *
- * THIS SOFTWARE IS PROVIDED ``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 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.
- */
-
-/* "$Id$" */
-
-#include "../../_pam_aconf.h"
-#include <sys/types.h>
-#include <sys/fsuid.h>
-#include <sys/wait.h>
-#include <errno.h>
-#include <fnmatch.h>
-#include <grp.h>
-#include <limits.h>
-#include <netdb.h>
-#include <pwd.h>
-#include <stdarg.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <syslog.h>
-#include <unistd.h>
-
-#include <security/pam_modules.h>
-#include <security/_pam_macros.h>
-#include <security/_pam_modutil.h>
-
-#define DATANAME "pam_xauth_cookie_file"
-#define XAUTHBIN "/usr/X11R6/bin/xauth"
-#define XAUTHENV "XAUTHORITY"
-#define HOMEENV "HOME"
-#define XAUTHDEF ".Xauthority"
-#define XAUTHTMP ".xauthXXXXXX"
-
-/* Run a given command (with a NULL-terminated argument list), feeding it the
- * given input on stdin, and storing any output it generates. */
-static int
-run_coprocess(const char *input, char **output,
- uid_t uid, gid_t gid, const char *command, ...)
-{
- int ipipe[2], opipe[2], i;
- char buf[LINE_MAX];
- pid_t child;
- char *buffer = NULL;
- size_t buffer_size = 0;
- va_list ap;
-
- *output = NULL;
-
- /* Create stdio pipery. */
- if (pipe(ipipe) == -1) {
- return -1;
- }
- if (pipe(opipe) == -1) {
- close(ipipe[0]);
- close(ipipe[1]);
- return -1;
- }
-
- /* Fork off a child. */
- child = fork();
- if (child == -1) {
- close(ipipe[0]);
- close(ipipe[1]);
- close(opipe[0]);
- close(opipe[1]);
- return -1;
- }
-
- if (child == 0) {
- /* We're the child. */
- char *args[10];
- const char *tmp;
- /* Drop privileges. */
- setgid(gid);
- setgroups(0, NULL);
- setuid(uid);
- /* Initialize the argument list. */
- memset(args, 0, sizeof(args));
- /* Set the pipe descriptors up as stdin and stdout, and close
- * everything else, including the original values for the
- * descriptors. */
- dup2(ipipe[0], STDIN_FILENO);
- dup2(opipe[1], STDOUT_FILENO);
- for (i = 0; i < sysconf(_SC_OPEN_MAX); i++) {
- if ((i != STDIN_FILENO) && (i != STDOUT_FILENO)) {
- close(i);
- }
- }
- /* Convert the varargs list into a regular array of strings. */
- va_start(ap, command);
- args[0] = strdup(command);
- for (i = 1; i < ((sizeof(args) / sizeof(args[0])) - 1); i++) {
- tmp = va_arg(ap, const char*);
- if (tmp == NULL) {
- break;
- }
- args[i] = strdup(tmp);
- }
- /* Run the command. */
- execvp(command, args);
- /* Never reached. */
- exit(1);
- }
-
- /* We're the parent, so close the other ends of the pipes. */
- close(ipipe[0]);
- close(opipe[1]);
- /* Send input to the process (if we have any), then send an EOF. */
- if (input) {
- (void)_pammodutil_write(ipipe[1], input, strlen(input));
- }
- close(ipipe[1]);
-
- /* Read data output until we run out of stuff to read. */
- i = _pammodutil_read(opipe[0], buf, sizeof(buf));
- while ((i != 0) && (i != -1)) {
- char *tmp;
- /* Resize the buffer to hold the data. */
- tmp = realloc(buffer, buffer_size + i + 1);
- if (tmp == NULL) {
- /* Uh-oh, bail. */
- if (buffer != NULL) {
- free(buffer);
- }
- close(opipe[0]);
- waitpid(child, NULL, 0);
- return -1;
- }
- /* Save the new buffer location, copy the newly-read data into
- * the buffer, and make sure the result will be
- * nul-terminated. */
- buffer = tmp;
- memcpy(buffer + buffer_size, buf, i);
- buffer[buffer_size + i] = '\0';
- buffer_size += i;
- /* Try to read again. */
- i = _pammodutil_read(opipe[0], buf, sizeof(buf));
- }
- /* No more data. Clean up and return data. */
- close(opipe[0]);
- *output = buffer;
- waitpid(child, NULL, 0);
- return 0;
-}
-
-/* Free a data item. */
-static void
-cleanup(pam_handle_t *pamh, void *data, int err)
-{
- free(data);
-}
-
-/* Check if we want to allow export to the other user, or import from the
- * other user. */
-static int
-check_acl(pam_handle_t *pamh,
- const char *sense, const char *this_user, const char *other_user,
- int noent_code, int debug)
-{
- char path[PATH_MAX];
- struct passwd *pwd;
- FILE *fp;
- int i;
- uid_t euid;
- /* Check this user's <sense> file. */
- pwd = _pammodutil_getpwnam(pamh, this_user);
- if (pwd == NULL) {
- syslog(LOG_ERR, "pam_xauth: error determining "
- "home directory for '%s'", this_user);
- return PAM_SESSION_ERR;
- }
- /* Figure out what that file is really named. */
- i = snprintf(path, sizeof(path), "%s/.xauth/%s", pwd->pw_dir, sense);
- if ((i >= sizeof(path)) || (i < 0)) {
- syslog(LOG_ERR, "pam_xauth: name of user's home directory "
- "is too long");
- return PAM_SESSION_ERR;
- }
- euid = geteuid();
- setfsuid(pwd->pw_uid);
- fp = fopen(path, "r");
- setfsuid(euid);
- if (fp != NULL) {
- char buf[LINE_MAX], *tmp;
- /* Scan the file for a list of specs of users to "trust". */
- while (fgets(buf, sizeof(buf), fp) != NULL) {
- tmp = memchr(buf, '\r', sizeof(buf));
- if (tmp != NULL) {
- *tmp = '\0';
- }
- tmp = memchr(buf, '\n', sizeof(buf));
- if (tmp != NULL) {
- *tmp = '\0';
- }
- if (fnmatch(buf, other_user, 0) == 0) {
- if (debug) {
- syslog(LOG_DEBUG, "pam_xauth: %s %s "
- "allowed by %s",
- other_user, sense, path);
- }
- fclose(fp);
- return PAM_SUCCESS;
- }
- }
- /* If there's no match in the file, we fail. */
- if (debug) {
- syslog(LOG_DEBUG, "pam_xauth: %s not listed in %s",
- other_user, path);
- }
- fclose(fp);
- return PAM_PERM_DENIED;
- } else {
- /* Default to okay if the file doesn't exist. */
- switch (errno) {
- case ENOENT:
- if (noent_code == PAM_SUCCESS) {
- if (debug) {
- syslog(LOG_DEBUG, "%s does not exist, "
- "ignoring", path);
- }
- } else {
- if (debug) {
- syslog(LOG_DEBUG, "%s does not exist, "
- "failing", path);
- }
- }
- return noent_code;
- default:
- if (debug) {
- syslog(LOG_ERR, "%s opening %s",
- strerror(errno), path);
- }
- return PAM_PERM_DENIED;
- }
- }
-}
-
-int
-pam_sm_open_session(pam_handle_t *pamh, int flags, int argc, const char **argv)
-{
- char xauthpath[] = XAUTHBIN;
- char *cookiefile = NULL, *xauthority = NULL,
- *cookie = NULL, *display = NULL, *tmp = NULL;
- const char *user, *xauth = xauthpath;
- struct passwd *tpwd, *rpwd;
- int fd, i, debug = 0;
- uid_t systemuser = 499, targetuser = 0, euid;
-
- /* Parse arguments. We don't understand many, so no sense in breaking
- * this into a separate function. */
- for (i = 0; i < argc; i++) {
- if (strcmp(argv[i], "debug") == 0) {
- debug = 1;
- continue;
- }
- if (strncmp(argv[i], "xauthpath=", 10) == 0) {
- xauth = argv[i] + 10;
- continue;
- }
- if (strncmp(argv[i], "targetuser=", 11) == 0) {
- long l = strtol(argv[i] + 11, &tmp, 10);
- if ((strlen(argv[i] + 11) > 0) && (*tmp == '\0')) {
- targetuser = l;
- } else {
- syslog(LOG_WARNING, "pam_xauth: invalid value "
- "for targetuser (`%s')", argv[i] + 11);
- }
- continue;
- }
- if (strncmp(argv[i], "systemuser=", 11) == 0) {
- long l = strtol(argv[i] + 11, &tmp, 10);
- if ((strlen(argv[i] + 11) > 0) && (*tmp == '\0')) {
- systemuser = l;
- } else {
- syslog(LOG_WARNING, "pam_xauth: invalid value "
- "for systemuser (`%s')", argv[i] + 11);
- }
- continue;
- }
- syslog(LOG_WARNING, "pam_xauth: unrecognized option `%s'",
- argv[i]);
- }
-
- /* If DISPLAY isn't set, we don't really care, now do we? */
- if ((display = getenv("DISPLAY")) == NULL) {
- if (debug) {
- syslog(LOG_DEBUG, "pam_xauth: user has no DISPLAY,"
- " doing nothing");
- }
- return PAM_SUCCESS;
- }
-
- /* Read the target user's name. */
- if (pam_get_user(pamh, &user, NULL) != PAM_SUCCESS) {
- syslog(LOG_ERR, "pam_xauth: error determining target "
- "user's name");
- return PAM_SESSION_ERR;
- }
- rpwd = _pammodutil_getpwuid(pamh, getuid());
- if (rpwd == NULL) {
- syslog(LOG_ERR, "pam_xauth: error determining invoking "
- "user's name");
- return PAM_SESSION_ERR;
- }
-
- /* Get the target user's UID and primary GID, which we'll need to set
- * on the xauthority file we create later on. */
- tpwd = _pammodutil_getpwnam(pamh, user);
- if (tpwd == NULL) {
- syslog(LOG_ERR, "pam_xauth: error determining target "
- "user's UID");
- return PAM_SESSION_ERR;
- }
-
- if (debug) {
- syslog(LOG_DEBUG, "pam_xauth: requesting user %lu/%lu, "
- "target user %lu/%lu",
- (unsigned long) rpwd->pw_uid,
- (unsigned long) rpwd->pw_gid,
- (unsigned long) tpwd->pw_uid,
- (unsigned long) tpwd->pw_gid);
- }
-
- /* If the UID is a system account (and not the superuser), forget
- * about forwarding keys. */
- if ((tpwd->pw_uid != 0) &&
- (tpwd->pw_uid != targetuser) &&
- (tpwd->pw_uid <= systemuser)) {
- if (debug) {
- syslog(LOG_DEBUG, "pam_xauth: not forwarding cookies "
- "to user ID %ld", (long) tpwd->pw_uid);
- }
- return PAM_SESSION_ERR;
- }
-
- /* Check that both users are amenable to this. By default, this
- * boils down to this policy:
- * export(ruser=root): only if <user> is listed in .xauth/export
- * export(ruser=*) if <user> is listed in .xauth/export, or
- * if .xauth/export does not exist
- * import(user=*): if <ruser> is listed in .xauth/import, or
- * if .xauth/import does not exist */
- i = (getuid() != 0) ? PAM_SUCCESS : PAM_PERM_DENIED;
- i = check_acl(pamh, "export", rpwd->pw_name, user, i, debug);
- if (i != PAM_SUCCESS) {
- return PAM_SESSION_ERR;
- }
- i = PAM_SUCCESS;
- i = check_acl(pamh, "import", user, rpwd->pw_name, i, debug);
- if (i != PAM_SUCCESS) {
- return PAM_SESSION_ERR;
- }
-
- /* Figure out where the source user's .Xauthority file is. */
- if (getenv(XAUTHENV) != NULL) {
- cookiefile = strdup(getenv(XAUTHENV));
- } else {
- cookiefile = malloc(strlen(rpwd->pw_dir) + 1 +
- strlen(XAUTHDEF) + 1);
- if (cookiefile == NULL) {
- return PAM_SESSION_ERR;
- }
- strcpy(cookiefile, rpwd->pw_dir);
- strcat(cookiefile, "/");
- strcat(cookiefile, XAUTHDEF);
- }
- if (debug) {
- syslog(LOG_DEBUG, "pam_xauth: reading keys from `%s'",
- cookiefile);
- }
-
- /* Read the user's .Xauthority file. Because the current UID is
- * the original user's UID, this will only fail if something has
- * gone wrong, or we have no cookies. */
- if (debug) {
- syslog(LOG_DEBUG, "pam_xauth: running \"%s %s %s %s %s\" as "
- "%lu/%lu",
- xauth,
- "-f",
- cookiefile,
- "nlist",
- display,
- (unsigned long) getuid(),
- (unsigned long) getgid());
- }
- if (run_coprocess(NULL, &cookie,
- getuid(), getgid(),
- xauth, "-f", cookiefile, "nlist", display,
- NULL) == 0) {
- /* Check that we got a cookie. If not, we get creative. */
- if (((cookie == NULL) || (strlen(cookie) == 0)) &&
- ((strncmp(display, "localhost:", 10) == 0) ||
- (strncmp(display, "localhost/unix:", 15) == 0))) {
- char *t, *screen;
- size_t tlen, slen;
- /* Free the useless cookie string. */
- if (cookie != NULL) {
- free(cookie);
- cookie = NULL;
- }
- /* Allocate enough space to hold an adjusted name. */
- tlen = strlen(display) + LINE_MAX + 1;
- t = malloc(tlen);
- if (t != NULL) {
- memset(t, 0, tlen);
- if (gethostname(t, tlen - 1) != -1) {
- /* Append the protocol and then the
- * screen number. */
- if (strlen(t) < tlen - 6) {
- strcat(t, "/unix:");
- }
- screen = strchr(display, ':');
- if (screen != NULL) {
- screen++;
- slen = strlen(screen);
- if (strlen(t) + slen < tlen) {
- strcat(t, screen);
- }
- }
- if (debug) {
- syslog(LOG_DEBUG, "pam_xauth: "
- "no key for `%s', trying"
- " `%s'", display, t);
- }
- /* Read the cookie for this display. */
- if (debug) {
- syslog(LOG_DEBUG,
- "pam_xauth: running "
- "\"%s %s %s %s %s\" as "
- "%lu/%lu",
- xauth,
- "-f",
- cookiefile,
- "nlist",
- t,
- (unsigned long) getuid(),
- (unsigned long) getgid());
- }
- run_coprocess(NULL, &cookie,
- getuid(), getgid(),
- xauth, "-f", cookiefile,
- "nlist", t, NULL);
- }
- free(t);
- t = NULL;
- }
- }
-
- /* Check that we got a cookie, this time for real. */
- if ((cookie == NULL) || (strlen(cookie) == 0)) {
- if (debug) {
- syslog(LOG_DEBUG, "pam_xauth: no key");
- }
- return PAM_SESSION_ERR;
- }
-
- /* Generate the environment variable
- * "XAUTHORITY=<homedir>/filename". */
- xauthority = malloc(strlen(XAUTHENV) + 1 +
- strlen(tpwd->pw_dir) + 1 +
- strlen(XAUTHTMP) + 1);
- if (xauthority == NULL) {
- if (debug) {
- syslog(LOG_DEBUG, "pam_xauth: no free memory");
- }
- free(cookiefile);
- free(cookie);
- return PAM_SESSION_ERR;
- }
- strcpy(xauthority, XAUTHENV);
- strcat(xauthority, "=");
- strcat(xauthority, tpwd->pw_dir);
- strcat(xauthority, "/");
- strcat(xauthority, XAUTHTMP);
-
- /* Generate a new file to hold the data. */
- euid = geteuid();
- setfsuid(tpwd->pw_uid);
- fd = mkstemp(xauthority + strlen(XAUTHENV) + 1);
- setfsuid(euid);
- if (fd == -1) {
- syslog(LOG_ERR, "pam_xauth: error creating "
- "temporary file `%s': %s",
- xauthority + strlen(XAUTHENV) + 1,
- strerror(errno));
- free(cookiefile);
- free(cookie);
- free(xauthority);
- return PAM_SESSION_ERR;
- }
- /* Set permissions on the new file and dispose of the
- * descriptor. */
- fchown(fd, tpwd->pw_uid, tpwd->pw_gid);
- close(fd);
-
- /* Get a copy of the filename to save as a data item for
- * removal at session-close time. */
- free(cookiefile);
- cookiefile = strdup(xauthority + strlen(XAUTHENV) + 1);
-
- /* Save the filename. */
- if (pam_set_data(pamh, DATANAME, cookiefile, cleanup) != PAM_SUCCESS) {
- syslog(LOG_ERR, "pam_xauth: error saving name of "
- "temporary file `%s'", cookiefile);
- unlink(cookiefile);
- free(xauthority);
- free(cookiefile);
- free(cookie);
- return PAM_SESSION_ERR;
- }
-
- /* Unset any old XAUTHORITY variable in the environment. */
- if (getenv (XAUTHENV))
- unsetenv (XAUTHENV);
-
- /* Set the new variable in the environment. */
- if (pam_putenv (pamh, xauthority) != PAM_SUCCESS)
- syslog (LOG_DEBUG, "pam_xauth: can't set environment variable '%s'",
- xauthority);
- putenv (xauthority); /* The environment owns this string now. */
-
- /* set $DISPLAY in pam handle to make su - work */
- {
- char *d = (char *) malloc (strlen ("DISPLAY=") +
- strlen (display) + 1);
- if (d == NULL)
- {
- syslog (LOG_DEBUG, "pam_xauth: memory exhausted\n");
- return PAM_SESSION_ERR;
- }
- strcpy (d, "DISPLAY=");
- strcat (d, display);
-
- if (pam_putenv (pamh, d) != PAM_SUCCESS)
- syslog (LOG_DEBUG,
- "pam_xauth: can't set environment variable '%s'",
- d);
- free (d);
- }
-
- /* Merge the cookie we read before into the new file. */
- if (debug) {
- syslog(LOG_DEBUG, "pam_xauth: writing key `%s' to "
- "temporary file `%s'", cookie, cookiefile);
- }
- if (debug) {
- syslog(LOG_DEBUG,
- "pam_xauth: running \"%s %s %s %s %s\" as "
- "%lu/%lu",
- xauth,
- "-f",
- cookiefile,
- "nmerge",
- "-",
- (unsigned long) tpwd->pw_uid,
- (unsigned long) tpwd->pw_gid);
- }
- run_coprocess(cookie, &tmp,
- tpwd->pw_uid, tpwd->pw_gid,
- xauth, "-f", cookiefile, "nmerge", "-", NULL);
-
- /* We don't need to keep a copy of these around any more. */
- free(cookie);
- cookie = NULL;
- }
- return PAM_SUCCESS;
-}
-
-int
-pam_sm_close_session(pam_handle_t *pamh, int flags, int argc, const char **argv)
-{
- void *cookiefile;
- int i, debug = 0;
-
- /* Parse arguments. We don't understand many, so no sense in breaking
- * this into a separate function. */
- for (i = 0; i < argc; i++) {
- if (strcmp(argv[i], "debug") == 0) {
- debug = 1;
- continue;
- }
- if (strncmp(argv[i], "xauthpath=", 10) == 0) {
- continue;
- }
- if (strncmp(argv[i], "systemuser=", 11) == 0) {
- continue;
- }
- if (strncmp(argv[i], "targetuser=", 11) == 0) {
- continue;
- }
- syslog(LOG_WARNING, "pam_xauth: unrecognized option `%s'",
- argv[i]);
- }
-
- /* Try to retrieve the name of a file we created when the session was
- * opened. */
- if (pam_get_data(pamh, DATANAME, (const void**) &cookiefile) == PAM_SUCCESS) {
- /* We'll only try to remove the file once. */
- if (strlen((char*)cookiefile) > 0) {
- if (debug) {
- syslog(LOG_DEBUG, "pam_xauth: removing `%s'",
- (char*)cookiefile);
- }
- unlink((char*)cookiefile);
- *((char*)cookiefile) = '\0';
- }
- }
- return PAM_SUCCESS;
-}
generated by cgit v1.2.3 (git 2.39.1) at 2025-04-29 03:26:23 +0000