+ logit("ROOT LOGIN REFUSED FROM %.200s", get_remote_ipaddr());
+ return 0;
+}
+
+
+/*
+ * Given a template and a passwd structure, build a filename
+ * by substituting % tokenised options. Currently, %% becomes '%',
+ * %h becomes the home directory and %u the username.
+ *
+ * This returns a buffer allocated by xmalloc.
+ */
+static char *
+expand_authorized_keys(const char *filename, struct passwd *pw)
+{
+ char *file, *ret;
+
+ file = percent_expand(filename, "h", pw->pw_dir,
+ "u", pw->pw_name, (char *)NULL);
+
+ /*
+ * Ensure that filename starts anchored. If not, be backward
+ * compatible and prepend the '%h/'
+ */
+ if (*file == '/')
+ return (file);
+
+ ret = xmalloc(MAXPATHLEN);
+ if (strlcpy(ret, pw->pw_dir, MAXPATHLEN) >= MAXPATHLEN ||
+ strlcat(ret, "/", MAXPATHLEN) >= MAXPATHLEN ||
+ strlcat(ret, file, MAXPATHLEN) >= MAXPATHLEN)
+ fatal("expand_authorized_keys: path too long");
+
+ xfree(file);
+ return (ret);
+}
+
+char *
+authorized_keys_file(struct passwd *pw)
+{
+ return expand_authorized_keys(options.authorized_keys_file, pw);
+}
+
+char *
+authorized_keys_file2(struct passwd *pw)
+{
+ return expand_authorized_keys(options.authorized_keys_file2, pw);
+}
+
+/* return ok if key exists in sysfile or userfile */
+HostStatus
+check_key_in_hostfiles(struct passwd *pw, Key *key, const char *host,
+ const char *sysfile, const char *userfile)
+{
+ Key *found;
+ char *user_hostfile;
+ struct stat st;
+ HostStatus host_status;
+
+ /* Check if we know the host and its host key. */
+ found = key_new(key->type);
+ host_status = check_host_in_hostfile(sysfile, host, key, found, NULL);
+
+ if (host_status != HOST_OK && userfile != NULL) {
+ user_hostfile = tilde_expand_filename(userfile, pw->pw_uid);
+ if (options.strict_modes &&
+ (stat(user_hostfile, &st) == 0) &&
+ ((st.st_uid != 0 && st.st_uid != pw->pw_uid) ||
+ (st.st_mode & 022) != 0)) {
+ logit("Authentication refused for %.100s: "
+ "bad owner or modes for %.200s",
+ pw->pw_name, user_hostfile);
+ } else {
+ temporarily_use_uid(pw);
+ host_status = check_host_in_hostfile(user_hostfile,
+ host, key, found, NULL);
+ restore_uid();
+ }
+ xfree(user_hostfile);
+ }
+ key_free(found);
+
+ debug2("check_key_in_hostfiles: key %s for %s", host_status == HOST_OK ?
+ "ok" : "not found", host);
+ return host_status;
+}
+
+
+/*
+ * Check a given file for security. This is defined as all components
+ * of the path to the file must be owned by either the owner of
+ * of the file or root and no directories must be group or world writable.
+ *
+ * XXX Should any specific check be done for sym links ?
+ *
+ * Takes an open file descriptor, the file name, a uid and and
+ * error buffer plus max size as arguments.
+ *
+ * Returns 0 on success and -1 on failure
+ */
+int
+secure_filename(FILE *f, const char *file, struct passwd *pw,
+ char *err, size_t errlen)
+{
+ uid_t uid = pw->pw_uid;
+ char buf[MAXPATHLEN], homedir[MAXPATHLEN];
+ char *cp;
+ int comparehome = 0;
+ struct stat st;
+
+ if (realpath(file, buf) == NULL) {
+ snprintf(err, errlen, "realpath %s failed: %s", file,
+ strerror(errno));
+ return -1;
+ }
+ if (realpath(pw->pw_dir, homedir) != NULL)
+ comparehome = 1;
+
+ /* check the open file to avoid races */
+ if (fstat(fileno(f), &st) < 0 ||
+ (st.st_uid != 0 && st.st_uid != uid) ||
+ (st.st_mode & 022) != 0) {
+ snprintf(err, errlen, "bad ownership or modes for file %s",
+ buf);
+ return -1;
+ }
+
+ /* for each component of the canonical path, walking upwards */
+ for (;;) {
+ if ((cp = dirname(buf)) == NULL) {
+ snprintf(err, errlen, "dirname() failed");
+ return -1;
+ }
+ strlcpy(buf, cp, sizeof(buf));
+
+ debug3("secure_filename: checking '%s'", buf);
+ if (stat(buf, &st) < 0 ||
+ (st.st_uid != 0 && st.st_uid != uid) ||
+ (st.st_mode & 022) != 0) {
+ snprintf(err, errlen,
+ "bad ownership or modes for directory %s", buf);
+ return -1;
+ }
+
+ /* If are passed the homedir then we can stop */
+ if (comparehome && strcmp(homedir, buf) == 0) {
+ debug3("secure_filename: terminating check at '%s'",
+ buf);
+ break;
+ }
+ /*
+ * dirname should always complete with a "/" path,
+ * but we can be paranoid and check for "." too
+ */
+ if ((strcmp("/", buf) == 0) || (strcmp(".", buf) == 0))
+ break;
+ }