--- /dev/null
+/*
+ fsck.c -- Check the configuration files for problems
+ Copyright (C) 2014 Guus Sliepen <guus@tinc-vpn.org>
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 2 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License along
+ with this program; if not, write to the Free Software Foundation, Inc.,
+ 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+*/
+
+#include "system.h"
+
+#include "crypto.h"
+#include "ecdsa.h"
+#include "ecdsagen.h"
+#include "fsck.h"
+#include "names.h"
+#ifndef DISABLE_LEGACY
+#include "rsa.h"
+#include "rsagen.h"
+#endif
+#include "tincctl.h"
+#include "utils.h"
+
+static bool ask_fix(void) {
+ if(force)
+ return true;
+ if(!tty)
+ return false;
+again:
+ fprintf(stderr, "Fix y/n? ");
+ char buf[1024];
+ if(!fgets(buf, sizeof buf, stdin)) {
+ tty = false;
+ return false;
+ }
+ if(buf[0] == 'y' || buf[0] == 'Y')
+ return true;
+ if(buf[0] == 'n' || buf[0] == 'N')
+ return false;
+ goto again;
+}
+
+static void print_tinc_cmd(const char *argv0, const char *format, ...) {
+ if(confbasegiven)
+ fprintf(stderr, "%s -c %s ", argv0, confbase);
+ else if(netname)
+ fprintf(stderr, "%s -n %s ", argv0, netname);
+ else
+ fprintf(stderr, "%s ", argv0);
+ va_list va;
+ va_start(va, format);
+ vfprintf(stderr, format, va);
+ va_end(va);
+ fputc('\n', stderr);
+}
+
+static int strtailcmp(const char *str, const char *tail) {
+ size_t slen = strlen(str);
+ size_t tlen = strlen(tail);
+ if(tlen > slen)
+ return -1;
+ return memcmp(str + slen - tlen, tail, tlen);
+}
+
+static void check_conffile(const char *fname, bool server) {
+ FILE *f = fopen(fname, "r");
+ if(!f) {
+ fprintf(stderr, "ERROR: cannot read %s: %s\n", fname, strerror(errno));
+ return;
+ }
+
+ char line[2048];
+ int lineno = 0;
+ bool skip = false;
+ const int maxvariables = 50;
+ int count[maxvariables];
+ memset(count, 0, sizeof count);
+
+ while(fgets(line, sizeof line, f)) {
+ if(skip) {
+ if(!strncmp(line, "-----END", 8))
+ skip = false;
+ continue;
+ } else {
+ if(!strncmp(line, "-----BEGIN", 10)) {
+ skip = true;
+ continue;
+ }
+ }
+
+ int len;
+ char *variable, *value, *eol;
+ variable = value = line;
+
+ lineno++;
+
+ eol = line + strlen(line);
+ while(strchr("\t \r\n", *--eol))
+ *eol = '\0';
+
+ if(!line[0] || line[0] == '#')
+ continue;
+
+ len = strcspn(value, "\t =");
+ value += len;
+ value += strspn(value, "\t ");
+ if(*value == '=') {
+ value++;
+ value += strspn(value, "\t ");
+ }
+ variable[len] = '\0';
+
+ bool found = false;
+
+ for(int i = 0; variables[i].name; i++) {
+ if(strcasecmp(variables[i].name, variable))
+ continue;
+
+ found = true;
+
+ if(variables[i].type & VAR_OBSOLETE) {
+ fprintf(stderr, "WARNING: obsolete variable %s in %s line %d\n", variable, fname, lineno);
+ }
+
+ if(i < maxvariables)
+ count[i]++;
+ }
+
+ if(!found)
+ fprintf(stderr, "WARNING: unknown variable %s in %s line %d\n", variable, fname, lineno);
+
+ if(!*value)
+ fprintf(stderr, "ERROR: no value for variable %s in %s line %d\n", variable, fname, lineno);
+ }
+
+ for(int i = 0; variables[i].name && i < maxvariables; i++) {
+ if(count[i] > 1 && !(variables[i].type & VAR_MULTIPLE))
+ fprintf(stderr, "WARNING: multiple instances of variable %s in %s\n", variables[i].name, fname);
+ }
+
+ if(ferror(f))
+ fprintf(stderr, "ERROR: while reading %s: %s\n", fname, strerror(errno));
+
+ fclose(f);
+}
+
+int fsck(const char *argv0) {
+ uid_t uid = getuid();
+
+ // Check that tinc.conf is readable.
+
+ if(access(tinc_conf, R_OK)) {
+ fprintf(stderr, "ERROR: cannot read %s: %s\n", tinc_conf, strerror(errno));
+ if(errno == ENOENT) {
+ fprintf(stderr, "No tinc configuration found. Create a new one with:\n\n");
+ print_tinc_cmd(argv0, "init");
+ } else if(errno == EACCES) {
+ if(uid != 0)
+ fprintf(stderr, "You are currently not running tinc as root. Use sudo?\n");
+ else
+ fprintf(stderr, "Check the permissions of each component of the path %s.\n", tinc_conf);
+ }
+ return 1;
+ }
+
+ char *name = get_my_name(true);
+ if(!name) {
+ fprintf(stderr, "ERROR: tinc cannot run without a valid Name.\n");
+ return 1;
+ }
+
+ // Check for private keys.
+ // TODO: use RSAPrivateKeyFile and Ed25519PrivateKeyFile variables if present.
+
+ struct stat st;
+ char fname[PATH_MAX];
+ char dname[PATH_MAX];
+
+#ifndef DISABLE_LEGACY
+ rsa_t *rsa_priv = NULL;
+ snprintf(fname, sizeof fname, "%s/rsa_key.priv", confbase);
+
+ if(stat(fname, &st)) {
+ if(errno != ENOENT) {
+ // Something is seriously wrong here. If we can access the directory with tinc.conf in it, we should certainly be able to stat() an existing file.
+ fprintf(stderr, "ERROR: cannot read %s: %s\n", fname, strerror(errno));
+ fprintf(stderr, "Please correct this error.\n");
+ return 1;
+ }
+ } else {
+ FILE *f = fopen(fname, "r");
+ if(!f) {
+ fprintf(stderr, "ERROR: could not open %s: %s\n", fname, strerror(errno));
+ return 1;
+ }
+ rsa_priv = rsa_read_pem_private_key(f);
+ fclose(f);
+ if(!rsa_priv) {
+ fprintf(stderr, "ERROR: No key or unusable key found in %s.\n", fname);
+ fprintf(stderr, "You can generate a new RSA key with:\n\n");
+ print_tinc_cmd(argv0, "generate-rsa-keys");
+ return 1;
+ }
+
+ if(st.st_mode & 077) {
+ fprintf(stderr, "WARNING: unsafe file permissions on %s.\n", fname);
+ if(st.st_uid != uid) {
+ fprintf(stderr, "You are not running %s as the same uid as %s.\n", argv0, fname);
+ } else if(ask_fix()) {
+ if(chmod(fname, st.st_mode & ~077))
+ fprintf(stderr, "ERROR: could not change permissions of %s: %s\n", fname, strerror(errno));
+ else
+ fprintf(stderr, "Fixed permissions of %s.\n", fname);
+ }
+ }
+ }
+#endif
+
+ ecdsa_t *ecdsa_priv = NULL;
+ snprintf(fname, sizeof fname, "%s/ed25519_key.priv", confbase);
+
+ if(stat(fname, &st)) {
+ if(errno != ENOENT) {
+ // Something is seriously wrong here. If we can access the directory with tinc.conf in it, we should certainly be able to stat() an existing file.
+ fprintf(stderr, "ERROR: cannot read %s: %s\n", fname, strerror(errno));
+ fprintf(stderr, "Please correct this error.\n");
+ return 1;
+ }
+ } else {
+ FILE *f = fopen(fname, "r");
+ if(!f) {
+ fprintf(stderr, "ERROR: could not open %s: %s\n", fname, strerror(errno));
+ return 1;
+ }
+ ecdsa_priv = ecdsa_read_pem_private_key(f);
+ fclose(f);
+ if(!ecdsa_priv) {
+ fprintf(stderr, "ERROR: No key or unusable key found in %s.\n", fname);
+ fprintf(stderr, "You can generate a new Ed25519 key with:\n\n");
+ print_tinc_cmd(argv0, "generate-ed25519-keys");
+ return 1;
+ }
+
+ if(st.st_mode & 077) {
+ fprintf(stderr, "WARNING: unsafe file permissions on %s.\n", fname);
+ if(st.st_uid != uid) {
+ fprintf(stderr, "You are not running %s as the same uid as %s.\n", argv0, fname);
+ } else if(ask_fix()) {
+ if(chmod(fname, st.st_mode & ~077))
+ fprintf(stderr, "ERROR: could not change permissions of %s: %s\n", fname, strerror(errno));
+ else
+ fprintf(stderr, "Fixed permissions of %s.\n", fname);
+ }
+ }
+ }
+
+#ifdef DISABLE_LEGACY
+ if(!ecdsa_priv) {
+ fprintf(stderr, "ERROR: No Ed25519 private key found.\n");
+#else
+ if(!rsa_priv && !ecdsa_priv) {
+ fprintf(stderr, "ERROR: Neither RSA or Ed25519 private key found.\n");
+#endif
+ fprintf(stderr, "You can generate new keys with:\n\n");
+ print_tinc_cmd(argv0, "generate-keys");
+ return 1;
+ }
+
+ // Check for public keys.
+ // TODO: use RSAPublicKeyFile and Ed25519PublicKeyFile variables if present.
+
+ snprintf(fname, sizeof fname, "%s/hosts/%s", confbase, name);
+ if(access(fname, R_OK))
+ fprintf(stderr, "WARNING: cannot read %s\n", fname);
+
+ FILE *f;
+
+#ifndef DISABLE_LEGACY
+ rsa_t *rsa_pub = NULL;
+
+ f = fopen(fname, "r");
+ if(f)
+ rsa_pub = rsa_read_pem_public_key(f);
+ fclose(f);
+
+ if(rsa_priv) {
+ if(!rsa_pub) {
+ fprintf(stderr, "WARNING: No (usable) public RSA key found.\n");
+ if(ask_fix()) {
+ FILE *f = fopen(fname, "a");
+ if(f) {
+ if(rsa_write_pem_public_key(rsa_priv, f))
+ fprintf(stderr, "Wrote RSA public key to %s.\n", fname);
+ else
+ fprintf(stderr, "ERROR: could not write RSA public key to %s.\n", fname);
+ fclose(f);
+ } else {
+ fprintf(stderr, "ERROR: could not append to %s: %s\n", fname, strerror(errno));
+ }
+ }
+ } else {
+ // TODO: suggest remedies
+ size_t len = rsa_size(rsa_priv);
+ if(len != rsa_size(rsa_pub)) {
+ fprintf(stderr, "ERROR: public and private RSA keys do not match.\n");
+ return 1;
+ }
+ char buf1[len], buf2[len], buf3[len];
+ randomize(buf1, sizeof buf1);
+ buf1[0] &= 0x7f;
+ memset(buf2, 0, sizeof buf2);
+ memset(buf3, 0, sizeof buf2);
+ if(!rsa_public_encrypt(rsa_pub, buf1, sizeof buf1, buf2)) {
+ fprintf(stderr, "ERROR: public RSA key does not work.\n");
+ return 1;
+ }
+ if(!rsa_private_decrypt(rsa_priv, buf2, sizeof buf2, buf3)) {
+ fprintf(stderr, "ERROR: private RSA key does not work.\n");
+ return 1;
+ }
+ if(memcmp(buf1, buf3, sizeof buf1)) {
+ fprintf(stderr, "ERROR: public and private RSA keys do not match.\n");
+ return 1;
+ }
+ }
+ } else {
+ if(rsa_pub)
+ fprintf(stderr, "WARNING: A public RSA key was found but no private key is known.\n");
+ }
+#endif
+ //
+ // TODO: this should read the Ed25519PublicKey config variable instead.
+ ecdsa_t *ecdsa_pub = NULL;
+
+ f = fopen(fname, "r");
+ if(f)
+ ecdsa_pub = ecdsa_read_pem_public_key(f);
+ fclose(f);
+
+ if(ecdsa_priv) {
+ if(!ecdsa_pub) {
+ fprintf(stderr, "WARNING: No (usable) public Ed25519 key found.\n");
+ if(ask_fix()) {
+ FILE *f = fopen(fname, "a");
+ if(f) {
+ if(ecdsa_write_pem_public_key(ecdsa_priv, f))
+ fprintf(stderr, "Wrote Ed25519 public key to %s.\n", fname);
+ else
+ fprintf(stderr, "ERROR: could not write Ed25519 public key to %s.\n", fname);
+ fclose(f);
+ } else {
+ fprintf(stderr, "ERROR: could not append to %s: %s\n", fname, strerror(errno));
+ }
+ }
+ } else {
+ // TODO: suggest remedies
+ char *key1 = ecdsa_get_base64_public_key(ecdsa_pub);
+ if(!key1) {
+ fprintf(stderr, "ERROR: public Ed25519 key does not work.\n");
+ return 1;
+ }
+ char *key2 = ecdsa_get_base64_public_key(ecdsa_priv);
+ if(!key2) {
+ free(key1);
+ fprintf(stderr, "ERROR: private Ed25519 key does not work.\n");
+ return 1;
+ }
+ int result = strcmp(key1, key2);
+ free(key1);
+ free(key2);
+ if(result) {
+ fprintf(stderr, "ERROR: public and private Ed25519 keys do not match.\n");
+ return 1;
+ }
+ }
+ } else {
+ if(ecdsa_pub)
+ fprintf(stderr, "WARNING: A public Ed25519 key was found but no private key is known.\n");
+ }
+
+ // Check whether scripts are executable
+
+ struct dirent *ent;
+ DIR *dir = opendir(confbase);
+ if(!dir) {
+ fprintf(stderr, "ERROR: cannot read directory %s: %s\n", confbase, strerror(errno));
+ return 1;
+ }
+
+ while((ent = readdir(dir))) {
+ if(strtailcmp(ent->d_name, "-up") && strtailcmp(ent->d_name, "-down"))
+ continue;
+
+ strncpy(fname, ent->d_name, sizeof fname);
+ char *dash = strrchr(fname, '-');
+ if(!dash)
+ continue;
+ *dash = 0;
+
+ if(strcmp(fname, "tinc") && strcmp(fname, "host") && strcmp(fname, "subnet")) {
+ static bool explained = false;
+ fprintf(stderr, "WARNING: Unknown script %s" SLASH "%s found.\n", confbase, ent->d_name);
+ if(!explained) {
+ fprintf(stderr, "The only scripts in %s executed by tinc are:\n", confbase);
+ fprintf(stderr, "tinc-up, tinc-down, host-up, host-down, subnet-up and subnet-down.\n");
+ explained = true;
+ }
+ continue;
+ }
+
+ snprintf(fname, sizeof fname, "%s" SLASH "%s", confbase, ent->d_name);
+ if(access(fname, R_OK | X_OK)) {
+ if(errno != EACCES) {
+ fprintf(stderr, "ERROR: cannot access %s: %s\n", fname, strerror(errno));
+ continue;
+ }
+ fprintf(stderr, "WARNING: cannot read and execute %s: %s\n", fname, strerror(errno));
+ if(ask_fix()) {
+ if(chmod(fname, 0755))
+ fprintf(stderr, "ERROR: cannot change permissions on %s: %s\n", fname, strerror(errno));
+ }
+ }
+ }
+ closedir(dir);
+
+ snprintf(dname, sizeof dname, "%s" SLASH "hosts", confbase);
+ dir = opendir(dname);
+ if(!dir) {
+ fprintf(stderr, "ERROR: cannot read directory %s: %s\n", dname, strerror(errno));
+ return 1;
+ }
+
+ while((ent = readdir(dir))) {
+ if(strtailcmp(ent->d_name, "-up") && strtailcmp(ent->d_name, "-down"))
+ continue;
+
+ strncpy(fname, ent->d_name, sizeof fname);
+ char *dash = strrchr(fname, '-');
+ if(!dash)
+ continue;
+ *dash = 0;
+
+ snprintf(fname, sizeof fname, "%s" SLASH "hosts" SLASH "%s", confbase, ent->d_name);
+ if(access(fname, R_OK | X_OK)) {
+ if(errno != EACCES) {
+ fprintf(stderr, "ERROR: cannot access %s: %s\n", fname, strerror(errno));
+ continue;
+ }
+ fprintf(stderr, "WARNING: cannot read and execute %s: %s\n", fname, strerror(errno));
+ if(ask_fix()) {
+ if(chmod(fname, 0755))
+ fprintf(stderr, "ERROR: cannot change permissions on %s: %s\n", fname, strerror(errno));
+ }
+ }
+ }
+ closedir(dir);
+
+ // Check for obsolete / unsafe / unknown configuration variables.
+
+ check_conffile(tinc_conf, true);
+
+ dir = opendir(dname);
+ if(dir) {
+ while((ent = readdir(dir))) {
+ if(!check_id(ent->d_name))
+ continue;
+
+ snprintf(fname, sizeof fname, "%s" SLASH "hosts" SLASH "%s", confbase, ent->d_name);
+ check_conffile(fname, false);
+ }
+ closedir(dir);
+ }
+
+ return 0;
+}
+
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