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IABSD.fr/src/usr.bin/ssh/ssh-add.c
djm
- usr.bin/ssh/ssh-add.c
-
/* $OpenBSD: ssh-add.c,v 1.156 2020/06/26 05:04:07 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 <sys/types.h> #include <sys/stat.h> #ifdef WITH_OPENSSL #include <openssl/evp.h> #endif #include <errno.h> #include <fcntl.h> #include <pwd.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <stdarg.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" #include "ssh-sk.h" /* argv0 */ extern char *__progname; /* Default files to add */ static char *default_files[] = { _PATH_SSH_CLIENT_ID_RSA, _PATH_SSH_CLIENT_ID_DSA, _PATH_SSH_CLIENT_ID_ECDSA, _PATH_SSH_CLIENT_ID_ECDSA_SK, _PATH_SSH_CLIENT_ID_ED25519, _PATH_SSH_CLIENT_ID_ED25519_SK, _PATH_SSH_CLIENT_ID_XMSS, NULL }; static int fingerprint_hash = SSH_FP_HASH_DEFAULT; /* Default lifetime (0 == forever) */ static long 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) { freezero(pass, strlen(pass)); pass = NULL; } } static int delete_one(int agent_fd, const struct sshkey *key, const char *comment, const char *path, int qflag) { int r; if ((r = ssh_remove_identity(agent_fd, key)) != 0) { fprintf(stderr, "Could not remove identity \"%s\": %s\n", path, ssh_err(r)); return r; } if (!qflag) { fprintf(stderr, "Identity removed: %s %s (%s)\n", path, sshkey_type(key), comment); } return 0; } static int delete_stdin(int agent_fd, int qflag) { char *line = NULL, *cp; size_t linesize = 0; struct sshkey *key = NULL; int lnum = 0, r, ret = -1; while (getline(&line, &linesize, stdin) != -1) { lnum++; sshkey_free(key); key = NULL; line[strcspn(line, "\n")] = '\0'; cp = line + strspn(line, " \t"); if (*cp == '#' || *cp == '\0') continue; if ((key = sshkey_new(KEY_UNSPEC)) == NULL) fatal("%s: sshkey_new", __func__); if ((r = sshkey_read(key, &cp)) != 0) { error("(stdin):%d: invalid key: %s", lnum, ssh_err(r)); continue; } if (delete_one(agent_fd, key, cp, "(stdin)", qflag) == 0) ret = 0; } sshkey_free(key); free(line); return ret; } 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 (strcmp(filename, "-") == 0) return delete_stdin(agent_fd, qflag); if ((r = sshkey_load_public(filename, &public, &comment)) != 0) { printf("Bad key file %s: %s\n", filename, ssh_err(r)); return -1; } if (delete_one(agent_fd, public, comment, filename, qflag) == 0) ret = 0; 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 (delete_one(agent_fd, cert, comment, certpath, qflag) == 0) ret = 0; 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, const char *skprovider) { 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)) == -1) { 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 ((r = sshbuf_load_fd(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 (!sshkey_is_sk(private)) skprovider = NULL; /* Don't send constraint for other keys */ else if (skprovider == NULL) { fprintf(stderr, "Cannot load authenticator-hosted key %s " "without provider\n", filename); goto out; } if ((r = ssh_add_identity_constrained(agent_fd, private, comment, lifetime, confirm, maxsign, skprovider)) == 0) { ret = 0; if (!qflag) { fprintf(stderr, "Identity added: %s (%s)\n", filename, comment); if (lifetime != 0) { fprintf(stderr, "Lifetime set to %ld 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, skprovider)) != 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 %ld 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 test_key(int agent_fd, const char *filename) { struct sshkey *key = NULL; u_char *sig = NULL; size_t slen = 0; int r, ret = -1; char data[1024]; if ((r = sshkey_load_public(filename, &key, NULL)) != 0) { error("Couldn't read public key %s: %s", filename, ssh_err(r)); return -1; } arc4random_buf(data, sizeof(data)); if ((r = ssh_agent_sign(agent_fd, key, &sig, &slen, data, sizeof(data), NULL, 0)) != 0) { error("Agent signature failed for %s: %s", filename, ssh_err(r)); goto done; } if ((r = sshkey_verify(key, sig, slen, data, sizeof(data), NULL, 0, NULL)) != 0) { error("Signature verification failed for %s: %s", filename, ssh_err(r)); goto done; } /* success */ ret = 0; done: free(sig); sshkey_free(key); 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; } freezero(p2, strlen(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)); } } freezero(p1, strlen(p1)); return (ret); } static int load_resident_keys(int agent_fd, const char *skprovider, int qflag) { struct sshkey **keys; size_t nkeys, i; int r, ok = 0; char *fp; pass = read_passphrase("Enter PIN for authenticator: ", RP_ALLOW_STDIN); if ((r = sshsk_load_resident(skprovider, NULL, pass, &keys, &nkeys)) != 0) { error("Unable to load resident keys: %s", ssh_err(r)); return r; } for (i = 0; i < nkeys; i++) { if ((fp = sshkey_fingerprint(keys[i], fingerprint_hash, SSH_FP_DEFAULT)) == NULL) fatal("%s: sshkey_fingerprint failed", __func__); if ((r = ssh_add_identity_constrained(agent_fd, keys[i], "", lifetime, confirm, maxsign, skprovider)) != 0) { error("Unable to add key %s %s", sshkey_type(keys[i]), fp); free(fp); ok = r; continue; } if (ok == 0) ok = 1; if (!qflag) { fprintf(stderr, "Resident identity added: %s %s\n", sshkey_type(keys[i]), fp); if (lifetime != 0) { fprintf(stderr, "Lifetime set to %ld seconds\n", lifetime); } if (confirm != 0) { fprintf(stderr, "The user must confirm " "each use of the key\n"); } } free(fp); sshkey_free(keys[i]); } free(keys); if (nkeys == 0) return SSH_ERR_KEY_NOT_FOUND; return ok == 1 ? 0 : ok; } static int do_file(int agent_fd, int deleting, int key_only, char *file, int qflag, const char *skprovider) { if (deleting) { if (delete_file(agent_fd, file, key_only, qflag) == -1) return -1; } else { if (add_file(agent_fd, file, key_only, qflag, skprovider) == -1) return -1; } return 0; } static void usage(void) { fprintf(stderr, "usage: ssh-add [-cDdKkLlqvXx] [-E fingerprint_hash] [-S provider] [-t life]\n" #ifdef WITH_XMSS " [-M maxsign] [-m minleft]\n" #endif " [file ...]\n" " ssh-add -s pkcs11\n" " ssh-add -e pkcs11\n" " ssh-add -T pubkey ...\n" ); } int main(int argc, char **argv) { extern char *optarg; extern int optind; int agent_fd; char *pkcs11provider = NULL, *skprovider = NULL; int r, i, ch, deleting = 0, ret = 0, key_only = 0, do_download = 0; int xflag = 0, lflag = 0, Dflag = 0, qflag = 0, Tflag = 0; SyslogFacility log_facility = SYSLOG_FACILITY_AUTH; LogLevel log_level = SYSLOG_LEVEL_INFO; /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */ sanitise_stdfd(); #ifdef WITH_OPENSSL OpenSSL_add_all_algorithms(); #endif log_init(__progname, log_level, log_facility, 1); 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); } skprovider = getenv("SSH_SK_PROVIDER"); while ((ch = getopt(argc, argv, "vkKlLcdDTxXE:e:M:m:qs:S:t:")) != -1) { switch (ch) { case 'v': if (log_level == SYSLOG_LEVEL_INFO) log_level = SYSLOG_LEVEL_DEBUG1; else if (log_level < SYSLOG_LEVEL_DEBUG3) log_level++; break; 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 'K': do_download = 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 'S': skprovider = optarg; break; case 'e': deleting = 1; pkcs11provider = optarg; break; case 't': if ((lifetime = convtime(optarg)) == -1 || lifetime < 0 || (u_long)lifetime > UINT32_MAX) { fprintf(stderr, "Invalid lifetime\n"); ret = 1; goto done; } break; case 'q': qflag = 1; break; case 'T': Tflag = 1; break; default: usage(); ret = 1; goto done; } } log_init(__progname, log_level, log_facility, 1); 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; } if (skprovider == NULL) skprovider = "internal"; argc -= optind; argv += optind; if (Tflag) { if (argc <= 0) fatal("no keys to test"); for (r = i = 0; i < argc; i++) r |= test_key(agent_fd, argv[i]); ret = r == 0 ? 0 : 1; goto done; } if (pkcs11provider != NULL) { if (update_card(agent_fd, !deleting, pkcs11provider, qflag) == -1) ret = 1; goto done; } if (do_download) { if (skprovider == NULL) fatal("Cannot download keys without provider"); if (load_resident_keys(agent_fd, skprovider, qflag) != 0) 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) == -1) continue; if (do_file(agent_fd, deleting, key_only, buf, qflag, skprovider) == -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, skprovider) == -1) ret = 1; } } done: clear_pass(); ssh_close_authentication_socket(agent_fd); return ret; }