]> git.meshlink.io Git - meshlink/blobdiff - src/libmeshlink.c
Write keys to file in tinc_setup
[meshlink] / src / libmeshlink.c
index 1631fb1aee9e72e32cdadf15f66b572ba70936e3..b4daff3d0a867b17cf670dbb23abbcd04db12c3e 100644 (file)
 */
 
 #include "libmeshlink.h"
+#include "crypto.h"
+#include "ecdsagen.h"
+char *hosts_dir = NULL;
+static char *name = NULL;
+char *tinc_conf = NULL;
+static bool tty = false;
 
+/* Open a file with the desired permissions, minus the umask.
+   Also, if we want to create an executable file, we call fchmod()
+   to set the executable bits. */
+
+FILE *fopenmask(const char *filename, const char *mode, mode_t perms) {
+       mode_t mask = umask(0);
+       perms &= ~mask;
+       umask(~perms);
+       FILE *f = fopen(filename, mode);
+#ifdef HAVE_FCHMOD
+       if((perms & 0444) && f)
+               fchmod(fileno(f), perms);
+#endif
+       umask(mask);
+       return f;
+}
+
+static void disable_old_keys(const char *filename, const char *what) {
+       char tmpfile[PATH_MAX] = "";
+       char buf[1024];
+       bool disabled = false;
+       bool block = false;
+       bool error = false;
+       FILE *r, *w;
+
+       r = fopen(filename, "r");
+       if(!r)
+               return;
+
+       snprintf(tmpfile, sizeof tmpfile, "%s.tmp", filename);
+
+       struct stat st = {.st_mode = 0600};
+       fstat(fileno(r), &st);
+       w = fopenmask(tmpfile, "w", st.st_mode);
+
+       while(fgets(buf, sizeof buf, r)) {
+               if(!block && !strncmp(buf, "-----BEGIN ", 11)) {
+                       if((strstr(buf, " EC ") && strstr(what, "ECDSA")) || (strstr(buf, " RSA ") && strstr(what, "RSA"))) {
+                               disabled = true;
+                               block = true;
+                       }
+               }
+
+               bool ecdsapubkey = !strncasecmp(buf, "ECDSAPublicKey", 14) && strchr(" \t=", buf[14]) && strstr(what, "ECDSA");
+
+               if(ecdsapubkey)
+                       disabled = true;
+
+               if(w) {
+                       if(block || ecdsapubkey)
+                               fputc('#', w);
+                       if(fputs(buf, w) < 0) {
+                               error = true;
+                               break;
+                       }
+               }
+
+               if(block && !strncmp(buf, "-----END ", 9))
+                       block = false;
+       }
+
+       if(w)
+               if(fclose(w) < 0)
+                       error = true;
+       if(ferror(r) || fclose(r) < 0)
+               error = true;
+
+       if(disabled) {
+               if(!w || error) {
+                       fprintf(stderr, "Warning: old key(s) found, remove them by hand!\n");
+                       if(w)
+                               unlink(tmpfile);
+                       return;
+               }
+
+#ifdef HAVE_MINGW
+               // We cannot atomically replace files on Windows.
+               char bakfile[PATH_MAX] = "";
+               snprintf(bakfile, sizeof bakfile, "%s.bak", filename);
+               if(rename(filename, bakfile) || rename(tmpfile, filename)) {
+                       rename(bakfile, filename);
+#else
+               if(rename(tmpfile, filename)) {
+#endif
+                       fprintf(stderr, "Warning: old key(s) found, remove them by hand!\n");
+               } else  {
+#ifdef HAVE_MINGW
+                       unlink(bakfile);
+#endif
+                       fprintf(stderr, "Warning: old key(s) found and disabled.\n");
+               }
+       }
+
+       unlink(tmpfile);
+}
+
+static FILE *ask_and_open(const char *filename, const char *what, const char *mode, bool ask, mode_t perms) {
+       FILE *r;
+       char *directory;
+       char buf[PATH_MAX];
+       char buf2[PATH_MAX];
+
+       /* Check stdin and stdout */
+       if(ask && tty) {
+               /* Ask for a file and/or directory name. */
+               fprintf(stderr, "Please enter a file to save %s to [%s]: ", what, filename);
+
+               if(fgets(buf, sizeof buf, stdin) == NULL) {
+                       fprintf(stderr, "Error while reading stdin: %s\n", strerror(errno));
+                       return NULL;
+               }
+
+               size_t len = strlen(buf);
+               if(len)
+                       buf[--len] = 0;
+
+               if(len)
+                       filename = buf;
+       }
+
+#ifdef HAVE_MINGW
+       if(filename[0] != '\\' && filename[0] != '/' && !strchr(filename, ':')) {
+#else
+       if(filename[0] != '/') {
+#endif
+               /* The directory is a relative path or a filename. */
+               directory = get_current_dir_name();
+               snprintf(buf2, sizeof buf2, "%s" SLASH "%s", directory, filename);
+               filename = buf2;
+       }
+
+       disable_old_keys(filename, what);
+
+       /* Open it first to keep the inode busy */
+
+       r = fopenmask(filename, mode, perms);
+
+       if(!r) {
+               fprintf(stderr, "Error opening file `%s': %s\n", filename, strerror(errno));
+               return NULL;
+       }
+
+       return r;
+}
+
+/*
+  Generate a public/private ECDSA keypair, and ask for a file to store
+  them in.
+*/
+bool ecdsa_keygen(bool ask) {
+       ecdsa_t *key;
+       FILE *f;
+       char *pubname, *privname;
+
+       fprintf(stderr, "Generating ECDSA keypair:\n");
+
+       if(!(key = ecdsa_generate())) {
+               fprintf(stderr, "Error during key generation!\n");
+               return false;
+       } else
+               fprintf(stderr, "Done.\n");
+
+       xasprintf(&privname, "%s" SLASH "ecdsa_key.priv", confbase);
+       f = ask_and_open(privname, "private ECDSA key", "a", ask, 0600);
+       free(privname);
+
+       if(!f)
+               return false;
+
+       if(!ecdsa_write_pem_private_key(key, f)) {
+               fprintf(stderr, "Error writing private key!\n");
+               ecdsa_free(key);
+               fclose(f);
+               return false;
+       }
+
+       fclose(f);
+
+       if(name)
+               xasprintf(&pubname, "%s" SLASH "hosts" SLASH "%s", confbase, name);
+       else
+               xasprintf(&pubname, "%s" SLASH "ecdsa_key.pub", confbase);
+
+       f = ask_and_open(pubname, "public ECDSA key", "a", ask, 0666);
+       free(pubname);
+
+       if(!f)
+               return false;
+
+       char *pubkey = ecdsa_get_base64_public_key(key);
+       fprintf(f, "ECDSAPublicKey = %s\n", pubkey);
+       free(pubkey);
+
+       fclose(f);
+       ecdsa_free(key);
+
+       return true;
+}
+
+/*
+  Generate a public/private RSA keypair, and ask for a file to store
+  them in.
+*/
+bool rsa_keygen(int bits, bool ask) {
+       rsa_t *key;
+       FILE *f;
+       char *pubname, *privname;
+
+       fprintf(stderr, "Generating %d bits keys:\n", bits);
+
+       if(!(key = rsa_generate(bits, 0x10001))) {
+               fprintf(stderr, "Error during key generation!\n");
+               return false;
+       } else
+               fprintf(stderr, "Done.\n");
+
+       xasprintf(&privname, "%s" SLASH "rsa_key.priv", confbase);
+       f = ask_and_open(privname, "private RSA key", "a", ask, 0600);
+       free(privname);
+
+       if(!f)
+               return false;
+
+       if(!rsa_write_pem_private_key(key, f)) {
+               fprintf(stderr, "Error writing private key!\n");
+               fclose(f);
+               rsa_free(key);
+               return false;
+       }
+
+       fclose(f);
+
+       if(name)
+               xasprintf(&pubname, "%s" SLASH "hosts" SLASH "%s", confbase, name);
+       else
+               xasprintf(&pubname, "%s" SLASH "rsa_key.pub", confbase);
+
+       f = ask_and_open(pubname, "public RSA key", "a", ask, 0666);
+       free(pubname);
+
+       if(!f)
+               return false;
+
+       if(!rsa_write_pem_public_key(key, f)) {
+               fprintf(stderr, "Error writing public key!\n");
+               fclose(f);
+               rsa_free(key);
+               return false;
+       }
+
+       fclose(f);
+       rsa_free(key);
+
+       return true;
+}
+
+static bool try_bind(int port) {
+       struct addrinfo *ai = NULL;
+       struct addrinfo hint = {
+               .ai_flags = AI_PASSIVE,
+               .ai_family = AF_UNSPEC,
+               .ai_socktype = SOCK_STREAM,
+               .ai_protocol = IPPROTO_TCP,
+       };
+
+       char portstr[16];
+       snprintf(portstr, sizeof portstr, "%d", port);
+
+       if(getaddrinfo(NULL, portstr, &hint, &ai) || !ai)
+               return false;
+
+       while(ai) {
+               int fd = socket(ai->ai_family, SOCK_STREAM, IPPROTO_TCP);
+               if(!fd)
+                       return false;
+               int result = bind(fd, ai->ai_addr, ai->ai_addrlen);
+               closesocket(fd);
+               if(result)
+                       return false;
+               ai = ai->ai_next;
+       }
+
+       return true;
+}
+
+int check_port(char *name) {
+       if(try_bind(655))
+               return 655;
+
+       fprintf(stderr, "Warning: could not bind to port 655. ");
+
+       for(int i = 0; i < 100; i++) {
+               int port = 0x1000 + (rand() & 0x7fff);
+               if(try_bind(port)) {
+                       char *filename;
+                       xasprintf(&filename, "%s" SLASH "hosts" SLASH "%s", confbase, name);
+                       FILE *f = fopen(filename, "a");
+                       free(filename);
+                       if(!f) {
+                               fprintf(stderr, "Please change tinc's Port manually.\n");
+                               return 0;
+                       }
+
+                       fprintf(f, "Port = %d\n", port);
+                       fclose(f);
+                       fprintf(stderr, "Tinc will instead listen on port %d.\n", port);
+                       return port;
+               }
+       }
+
+       fprintf(stderr, "Please change tinc's Port manually.\n");
+       return 0;
+}
 //tinc_setup() should basically do what cmd_init() from src/tincctl.c does, except it doesn't have to generate a tinc-up script.
-bool tinc_setup(const char* path) {
+bool tinc_setup(const char* confbaseapi, const char* name) {
+       confbase = confbaseapi;
+       make_names();
+        xasprintf(&tinc_conf, "%s" SLASH "tinc.conf", confbase);
+        xasprintf(&hosts_dir, "%s" SLASH "hosts", confbase);
+       if(!access(tinc_conf, F_OK)) {
+               fprintf(stderr, "Configuration file %s already exists!\n", tinc_conf);
+               return false;
+       }
+
+       if(!check_id(name)) {
+               fprintf(stderr, "Invalid Name! Only a-z, A-Z, 0-9 and _ are allowed characters.\n");
+               return false;
+       }
+
+       if(!confbase_given && mkdir(confdir, 0755) && errno != EEXIST) {
+               fprintf(stderr, "Could not create directory %s: %s\n", confdir, strerror(errno));
+               return false;
+       }
+
+       if(mkdir(confbase, 0777) && errno != EEXIST) {
+               fprintf(stderr, "Could not create directory %s: %s\n", confbase, strerror(errno));
+               return false;
+       }
+
+       if(mkdir(hosts_dir, 0777) && errno != EEXIST) {
+               fprintf(stderr, "Could not create directory %s: %s\n", hosts_dir, strerror(errno));
+               return false;
+       }
+
+       FILE *f = fopen(tinc_conf, "w");
+       if(!f) {
+               fprintf(stderr, "Could not create file %s: %s\n", tinc_conf, strerror(errno));
+               return 1;
+       }
+
+       fprintf(f, "Name = %s\n", name);
+       fclose(f);
+
+       if(!rsa_keygen(2048, false) || !ecdsa_keygen(false))
+               return false;
+
+       check_port(name);
+
+       return true;
 
-init_configuration(&config_tree);
+}
 
-return true;
-};
 
 bool tinc_start(const char* path);