diff options
Diffstat (limited to 'ssh-add.c')
| -rw-r--r-- | ssh-add.c | 699 |
1 files changed, 699 insertions, 0 deletions
diff --git a/ssh-add.c b/ssh-add.c new file mode 100644 index 0000000..627c029 --- /dev/null +++ b/ssh-add.c @@ -0,0 +1,699 @@ +/* $OpenBSD: ssh-add.c,v 1.136 2018/09/19 02:03:02 djm Exp $ */ +/* + * Author: Tatu Ylonen <ylo@cs.hut.fi> + * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland + * All rights reserved + * Adds an identity to the authentication server, or removes an identity. + * + * As far as I am concerned, the code I have written for this software + * can be used freely for any purpose. Any derived versions of this + * software must be clearly marked as such, and if the derived work is + * incompatible with the protocol description in the RFC file, it must be + * called by a name other than "ssh" or "Secure Shell". + * + * SSH2 implementation, + * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved. + * + * 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, this list of conditions and the following disclaimer. + * 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. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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. + */ + +#include "includes.h" + +#include <sys/types.h> +#include <sys/stat.h> + +#include <openssl/evp.h> +#include "openbsd-compat/openssl-compat.h" + +#include <errno.h> +#include <fcntl.h> +#include <pwd.h> +#include <stdarg.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> +#include <limits.h> + +#include "xmalloc.h" +#include "ssh.h" +#include "log.h" +#include "sshkey.h" +#include "sshbuf.h" +#include "authfd.h" +#include "authfile.h" +#include "pathnames.h" +#include "misc.h" +#include "ssherr.h" +#include "digest.h" + +/* argv0 */ +extern char *__progname; + +/* Default files to add */ +static char *default_files[] = { +#ifdef WITH_OPENSSL + _PATH_SSH_CLIENT_ID_RSA, + _PATH_SSH_CLIENT_ID_DSA, +#ifdef OPENSSL_HAS_ECC + _PATH_SSH_CLIENT_ID_ECDSA, +#endif +#endif /* WITH_OPENSSL */ + _PATH_SSH_CLIENT_ID_ED25519, + _PATH_SSH_CLIENT_ID_XMSS, + NULL +}; + +static int fingerprint_hash = SSH_FP_HASH_DEFAULT; + +/* Default lifetime (0 == forever) */ +static int lifetime = 0; + +/* User has to confirm key use */ +static int confirm = 0; + +/* Maximum number of signatures (XMSS) */ +static u_int maxsign = 0; +static u_int minleft = 0; + +/* we keep a cache of one passphrase */ +static char *pass = NULL; +static void +clear_pass(void) +{ + if (pass) { + explicit_bzero(pass, strlen(pass)); + free(pass); + pass = NULL; + } +} + +static int +delete_file(int agent_fd, const char *filename, int key_only, int qflag) +{ + struct sshkey *public, *cert = NULL; + char *certpath = NULL, *comment = NULL; + int r, ret = -1; + + if ((r = sshkey_load_public(filename, &public, &comment)) != 0) { + printf("Bad key file %s: %s\n", filename, ssh_err(r)); + return -1; + } + if ((r = ssh_remove_identity(agent_fd, public)) == 0) { + if (!qflag) { + fprintf(stderr, "Identity removed: %s (%s)\n", + filename, comment); + } + ret = 0; + } else + fprintf(stderr, "Could not remove identity \"%s\": %s\n", + filename, ssh_err(r)); + + if (key_only) + goto out; + + /* Now try to delete the corresponding certificate too */ + free(comment); + comment = NULL; + xasprintf(&certpath, "%s-cert.pub", filename); + if ((r = sshkey_load_public(certpath, &cert, &comment)) != 0) { + if (r != SSH_ERR_SYSTEM_ERROR || errno != ENOENT) + error("Failed to load certificate \"%s\": %s", + certpath, ssh_err(r)); + goto out; + } + + if (!sshkey_equal_public(cert, public)) + fatal("Certificate %s does not match private key %s", + certpath, filename); + + if ((r = ssh_remove_identity(agent_fd, cert)) == 0) { + if (!qflag) { + fprintf(stderr, "Identity removed: %s (%s)\n", + certpath, comment); + } + ret = 0; + } else + fprintf(stderr, "Could not remove identity \"%s\": %s\n", + certpath, ssh_err(r)); + + out: + sshkey_free(cert); + sshkey_free(public); + free(certpath); + free(comment); + + return ret; +} + +/* Send a request to remove all identities. */ +static int +delete_all(int agent_fd, int qflag) +{ + int ret = -1; + + /* + * Since the agent might be forwarded, old or non-OpenSSH, when asked + * to remove all keys, attempt to remove both protocol v.1 and v.2 + * keys. + */ + if (ssh_remove_all_identities(agent_fd, 2) == 0) + ret = 0; + /* ignore error-code for ssh1 */ + ssh_remove_all_identities(agent_fd, 1); + + if (ret != 0) + fprintf(stderr, "Failed to remove all identities.\n"); + else if (!qflag) + fprintf(stderr, "All identities removed.\n"); + + return ret; +} + +static int +add_file(int agent_fd, const char *filename, int key_only, int qflag) +{ + struct sshkey *private, *cert; + char *comment = NULL; + char msg[1024], *certpath = NULL; + int r, fd, ret = -1; + size_t i; + u_int32_t left; + struct sshbuf *keyblob; + struct ssh_identitylist *idlist; + + if (strcmp(filename, "-") == 0) { + fd = STDIN_FILENO; + filename = "(stdin)"; + } else if ((fd = open(filename, O_RDONLY)) < 0) { + perror(filename); + return -1; + } + + /* + * Since we'll try to load a keyfile multiple times, permission errors + * will occur multiple times, so check perms first and bail if wrong. + */ + if (fd != STDIN_FILENO) { + if (sshkey_perm_ok(fd, filename) != 0) { + close(fd); + return -1; + } + } + if ((keyblob = sshbuf_new()) == NULL) + fatal("%s: sshbuf_new failed", __func__); + if ((r = sshkey_load_file(fd, keyblob)) != 0) { + fprintf(stderr, "Error loading key \"%s\": %s\n", + filename, ssh_err(r)); + sshbuf_free(keyblob); + close(fd); + return -1; + } + close(fd); + + /* At first, try empty passphrase */ + if ((r = sshkey_parse_private_fileblob(keyblob, "", &private, + &comment)) != 0 && r != SSH_ERR_KEY_WRONG_PASSPHRASE) { + fprintf(stderr, "Error loading key \"%s\": %s\n", + filename, ssh_err(r)); + goto fail_load; + } + /* try last */ + if (private == NULL && pass != NULL) { + if ((r = sshkey_parse_private_fileblob(keyblob, pass, &private, + &comment)) != 0 && r != SSH_ERR_KEY_WRONG_PASSPHRASE) { + fprintf(stderr, "Error loading key \"%s\": %s\n", + filename, ssh_err(r)); + goto fail_load; + } + } + if (private == NULL) { + /* clear passphrase since it did not work */ + clear_pass(); + snprintf(msg, sizeof msg, "Enter passphrase for %s%s: ", + filename, confirm ? " (will confirm each use)" : ""); + for (;;) { + pass = read_passphrase(msg, RP_ALLOW_STDIN); + if (strcmp(pass, "") == 0) + goto fail_load; + if ((r = sshkey_parse_private_fileblob(keyblob, pass, + &private, &comment)) == 0) + break; + else if (r != SSH_ERR_KEY_WRONG_PASSPHRASE) { + fprintf(stderr, + "Error loading key \"%s\": %s\n", + filename, ssh_err(r)); + fail_load: + clear_pass(); + sshbuf_free(keyblob); + return -1; + } + clear_pass(); + snprintf(msg, sizeof msg, + "Bad passphrase, try again for %s%s: ", filename, + confirm ? " (will confirm each use)" : ""); + } + } + if (comment == NULL || *comment == '\0') + comment = xstrdup(filename); + sshbuf_free(keyblob); + + /* For XMSS */ + if ((r = sshkey_set_filename(private, filename)) != 0) { + fprintf(stderr, "Could not add filename to private key: %s (%s)\n", + filename, comment); + goto out; + } + if (maxsign && minleft && + (r = ssh_fetch_identitylist(agent_fd, &idlist)) == 0) { + for (i = 0; i < idlist->nkeys; i++) { + if (!sshkey_equal_public(idlist->keys[i], private)) + continue; + left = sshkey_signatures_left(idlist->keys[i]); + if (left < minleft) { + fprintf(stderr, + "Only %d signatures left.\n", left); + break; + } + fprintf(stderr, "Skipping update: "); + if (left == minleft) { + fprintf(stderr, + "required signatures left (%d).\n", left); + } else { + fprintf(stderr, + "more signatures left (%d) than" + " required (%d).\n", left, minleft); + } + ssh_free_identitylist(idlist); + goto out; + } + ssh_free_identitylist(idlist); + } + + if ((r = ssh_add_identity_constrained(agent_fd, private, comment, + lifetime, confirm, maxsign)) == 0) { + ret = 0; + if (!qflag) { + fprintf(stderr, "Identity added: %s (%s)\n", + filename, comment); + if (lifetime != 0) { + fprintf(stderr, + "Lifetime set to %d seconds\n", lifetime); + } + if (confirm != 0) { + fprintf(stderr, "The user must confirm " + "each use of the key\n"); + } + } + } else { + fprintf(stderr, "Could not add identity \"%s\": %s\n", + filename, ssh_err(r)); + } + + /* Skip trying to load the cert if requested */ + if (key_only) + goto out; + + /* Now try to add the certificate flavour too */ + xasprintf(&certpath, "%s-cert.pub", filename); + if ((r = sshkey_load_public(certpath, &cert, NULL)) != 0) { + if (r != SSH_ERR_SYSTEM_ERROR || errno != ENOENT) + error("Failed to load certificate \"%s\": %s", + certpath, ssh_err(r)); + goto out; + } + + if (!sshkey_equal_public(cert, private)) { + error("Certificate %s does not match private key %s", + certpath, filename); + sshkey_free(cert); + goto out; + } + + /* Graft with private bits */ + if ((r = sshkey_to_certified(private)) != 0) { + error("%s: sshkey_to_certified: %s", __func__, ssh_err(r)); + sshkey_free(cert); + goto out; + } + if ((r = sshkey_cert_copy(cert, private)) != 0) { + error("%s: sshkey_cert_copy: %s", __func__, ssh_err(r)); + sshkey_free(cert); + goto out; + } + sshkey_free(cert); + + if ((r = ssh_add_identity_constrained(agent_fd, private, comment, + lifetime, confirm, maxsign)) != 0) { + error("Certificate %s (%s) add failed: %s", certpath, + private->cert->key_id, ssh_err(r)); + goto out; + } + /* success */ + if (!qflag) { + fprintf(stderr, "Certificate added: %s (%s)\n", certpath, + private->cert->key_id); + if (lifetime != 0) { + fprintf(stderr, "Lifetime set to %d seconds\n", + lifetime); + } + if (confirm != 0) { + fprintf(stderr, "The user must confirm each use " + "of the key\n"); + } + } + + out: + free(certpath); + free(comment); + sshkey_free(private); + + return ret; +} + +static int +update_card(int agent_fd, int add, const char *id, int qflag) +{ + char *pin = NULL; + int r, ret = -1; + + if (add) { + if ((pin = read_passphrase("Enter passphrase for PKCS#11: ", + RP_ALLOW_STDIN)) == NULL) + return -1; + } + + if ((r = ssh_update_card(agent_fd, add, id, pin == NULL ? "" : pin, + lifetime, confirm)) == 0) { + ret = 0; + if (!qflag) { + fprintf(stderr, "Card %s: %s\n", + add ? "added" : "removed", id); + } + } else { + fprintf(stderr, "Could not %s card \"%s\": %s\n", + add ? "add" : "remove", id, ssh_err(r)); + ret = -1; + } + free(pin); + return ret; +} + +static int +list_identities(int agent_fd, int do_fp) +{ + char *fp; + int r; + struct ssh_identitylist *idlist; + u_int32_t left; + size_t i; + + if ((r = ssh_fetch_identitylist(agent_fd, &idlist)) != 0) { + if (r != SSH_ERR_AGENT_NO_IDENTITIES) + fprintf(stderr, "error fetching identities: %s\n", + ssh_err(r)); + else + printf("The agent has no identities.\n"); + return -1; + } + for (i = 0; i < idlist->nkeys; i++) { + if (do_fp) { + fp = sshkey_fingerprint(idlist->keys[i], + fingerprint_hash, SSH_FP_DEFAULT); + printf("%u %s %s (%s)\n", sshkey_size(idlist->keys[i]), + fp == NULL ? "(null)" : fp, idlist->comments[i], + sshkey_type(idlist->keys[i])); + free(fp); + } else { + if ((r = sshkey_write(idlist->keys[i], stdout)) != 0) { + fprintf(stderr, "sshkey_write: %s\n", + ssh_err(r)); + continue; + } + fprintf(stdout, " %s", idlist->comments[i]); + left = sshkey_signatures_left(idlist->keys[i]); + if (left > 0) + fprintf(stdout, + " [signatures left %d]", left); + fprintf(stdout, "\n"); + } + } + ssh_free_identitylist(idlist); + return 0; +} + +static int +lock_agent(int agent_fd, int lock) +{ + char prompt[100], *p1, *p2; + int r, passok = 1, ret = -1; + + strlcpy(prompt, "Enter lock password: ", sizeof(prompt)); + p1 = read_passphrase(prompt, RP_ALLOW_STDIN); + if (lock) { + strlcpy(prompt, "Again: ", sizeof prompt); + p2 = read_passphrase(prompt, RP_ALLOW_STDIN); + if (strcmp(p1, p2) != 0) { + fprintf(stderr, "Passwords do not match.\n"); + passok = 0; + } + explicit_bzero(p2, strlen(p2)); + free(p2); + } + if (passok) { + if ((r = ssh_lock_agent(agent_fd, lock, p1)) == 0) { + fprintf(stderr, "Agent %slocked.\n", lock ? "" : "un"); + ret = 0; + } else { + fprintf(stderr, "Failed to %slock agent: %s\n", + lock ? "" : "un", ssh_err(r)); + } + } + explicit_bzero(p1, strlen(p1)); + free(p1); + return (ret); +} + +static int +do_file(int agent_fd, int deleting, int key_only, char *file, int qflag) +{ + if (deleting) { + if (delete_file(agent_fd, file, key_only, qflag) == -1) + return -1; + } else { + if (add_file(agent_fd, file, key_only, qflag) == -1) + return -1; + } + return 0; +} + +static void +usage(void) +{ + fprintf(stderr, "usage: %s [options] [file ...]\n", __progname); + fprintf(stderr, "Options:\n"); + fprintf(stderr, " -l List fingerprints of all identities.\n"); + fprintf(stderr, " -E hash Specify hash algorithm used for fingerprints.\n"); + fprintf(stderr, " -L List public key parameters of all identities.\n"); + fprintf(stderr, " -k Load only keys and not certificates.\n"); + fprintf(stderr, " -c Require confirmation to sign using identities\n"); + fprintf(stderr, " -m minleft Maxsign is only changed if less than minleft are left (for XMSS)\n"); + fprintf(stderr, " -M maxsign Maximum number of signatures allowed (for XMSS)\n"); + fprintf(stderr, " -t life Set lifetime (in seconds) when adding identities.\n"); + fprintf(stderr, " -d Delete identity.\n"); + fprintf(stderr, " -D Delete all identities.\n"); + fprintf(stderr, " -x Lock agent.\n"); + fprintf(stderr, " -X Unlock agent.\n"); + fprintf(stderr, " -s pkcs11 Add keys from PKCS#11 provider.\n"); + fprintf(stderr, " -e pkcs11 Remove keys provided by PKCS#11 provider.\n"); + fprintf(stderr, " -q Be quiet after a successful operation.\n"); +} + +int +main(int argc, char **argv) +{ + extern char *optarg; + extern int optind; + int agent_fd; + char *pkcs11provider = NULL; + int r, i, ch, deleting = 0, ret = 0, key_only = 0; + int xflag = 0, lflag = 0, Dflag = 0, qflag = 0; + + ssh_malloc_init(); /* must be called before any mallocs */ + /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */ + sanitise_stdfd(); + + __progname = ssh_get_progname(argv[0]); + seed_rng(); + +#ifdef WITH_OPENSSL + OpenSSL_add_all_algorithms(); +#endif + + setvbuf(stdout, NULL, _IOLBF, 0); + + /* First, get a connection to the authentication agent. */ + switch (r = ssh_get_authentication_socket(&agent_fd)) { + case 0: + break; + case SSH_ERR_AGENT_NOT_PRESENT: + fprintf(stderr, "Could not open a connection to your " + "authentication agent.\n"); + exit(2); + default: + fprintf(stderr, "Error connecting to agent: %s\n", ssh_err(r)); + exit(2); + } + + while ((ch = getopt(argc, argv, "klLcdDxXE:e:M:m:qs:t:")) != -1) { + switch (ch) { + case 'E': + fingerprint_hash = ssh_digest_alg_by_name(optarg); + if (fingerprint_hash == -1) + fatal("Invalid hash algorithm \"%s\"", optarg); + break; + case 'k': + key_only = 1; + break; + case 'l': + case 'L': + if (lflag != 0) + fatal("-%c flag already specified", lflag); + lflag = ch; + break; + case 'x': + case 'X': + if (xflag != 0) + fatal("-%c flag already specified", xflag); + xflag = ch; + break; + case 'c': + confirm = 1; + break; + case 'm': + minleft = (int)strtonum(optarg, 1, UINT_MAX, NULL); + if (minleft == 0) { + usage(); + ret = 1; + goto done; + } + break; + case 'M': + maxsign = (int)strtonum(optarg, 1, UINT_MAX, NULL); + if (maxsign == 0) { + usage(); + ret = 1; + goto done; + } + break; + case 'd': + deleting = 1; + break; + case 'D': + Dflag = 1; + break; + case 's': + pkcs11provider = optarg; + break; + case 'e': + deleting = 1; + pkcs11provider = optarg; + break; + case 't': + if ((lifetime = convtime(optarg)) == -1) { + fprintf(stderr, "Invalid lifetime\n"); + ret = 1; + goto done; + } + break; + case 'q': + qflag = 1; + break; + default: + usage(); + ret = 1; + goto done; + } + } + + if ((xflag != 0) + (lflag != 0) + (Dflag != 0) > 1) + fatal("Invalid combination of actions"); + else if (xflag) { + if (lock_agent(agent_fd, xflag == 'x' ? 1 : 0) == -1) + ret = 1; + goto done; + } else if (lflag) { + if (list_identities(agent_fd, lflag == 'l' ? 1 : 0) == -1) + ret = 1; + goto done; + } else if (Dflag) { + if (delete_all(agent_fd, qflag) == -1) + ret = 1; + goto done; + } + + argc -= optind; + argv += optind; + if (pkcs11provider != NULL) { + if (update_card(agent_fd, !deleting, pkcs11provider, + qflag) == -1) + ret = 1; + goto done; + } + if (argc == 0) { + char buf[PATH_MAX]; + struct passwd *pw; + struct stat st; + int count = 0; + + if ((pw = getpwuid(getuid())) == NULL) { + fprintf(stderr, "No user found with uid %u\n", + (u_int)getuid()); + ret = 1; + goto done; + } + + for (i = 0; default_files[i]; i++) { + snprintf(buf, sizeof(buf), "%s/%s", pw->pw_dir, + default_files[i]); + if (stat(buf, &st) < 0) + continue; + if (do_file(agent_fd, deleting, key_only, buf, + qflag) == -1) + ret = 1; + else + count++; + } + if (count == 0) + ret = 1; + } else { + for (i = 0; i < argc; i++) { + if (do_file(agent_fd, deleting, key_only, + argv[i], qflag) == -1) + ret = 1; + } + } + clear_pass(); + +done: + ssh_close_authentication_socket(agent_fd); + return ret; +} |