ssh-keygen.c

OpenSSH 是 SSH （Secure SHell） 协议的免费开源实现。它用安全、加密的网络连接工具代替了 telnet、ftp、 rlogin、rsh 和 rcp 工具。OpenSSH 支持

	}
	xfree(keys);
	exit(0);
}
#endif /* SMARTCARD */

static void
do_fingerprint(struct passwd *pw)
{
	FILE *f;
	Key *public;
	char *comment = NULL, *cp, *ep, line[16*1024], *fp;
	int i, skip = 0, num = 1, invalid = 1;
	enum fp_rep rep;
	enum fp_type fptype;
	struct stat st;

	fptype = print_bubblebabble ? SSH_FP_SHA1 : SSH_FP_MD5;
	rep =    print_bubblebabble ? SSH_FP_BUBBLEBABBLE : SSH_FP_HEX;

	if (!have_identity)
		ask_filename(pw, "Enter file in which the key is");
	if (stat(identity_file, &st) < 0) {
		perror(identity_file);
		exit(1);
	}
	public = key_load_public(identity_file, &comment);
	if (public != NULL) {
		fp = key_fingerprint(public, fptype, rep);
		printf("%u %s %s\n", key_size(public), fp, comment);
		key_free(public);
		xfree(comment);
		xfree(fp);
		exit(0);
	}
	if (comment)
		xfree(comment);

	f = fopen(identity_file, "r");
	if (f != NULL) {
		while (fgets(line, sizeof(line), f)) {
			i = strlen(line) - 1;
			if (line[i] != '\n') {
				error("line %d too long: %.40s...", num, line);
				skip = 1;
				continue;
			}
			num++;
			if (skip) {
				skip = 0;
				continue;
			}
			line[i] = '\0';

			/* Skip leading whitespace, empty and comment lines. */
			for (cp = line; *cp == ' ' || *cp == '\t'; cp++)
				;
			if (!*cp || *cp == '\n' || *cp == '#')
				continue ;
			i = strtol(cp, &ep, 10);
			if (i == 0 || ep == NULL || (*ep != ' ' && *ep != '\t')) {
				int quoted = 0;
				comment = cp;
				for (; *cp && (quoted || (*cp != ' ' &&
				    *cp != '\t')); cp++) {
					if (*cp == '\\' && cp[1] == '"')
						cp++;	/* Skip both */
					else if (*cp == '"')
						quoted = !quoted;
				}
				if (!*cp)
					continue;
				*cp++ = '\0';
			}
			ep = cp;
			public = key_new(KEY_RSA1);
			if (key_read(public, &cp) != 1) {
				cp = ep;
				key_free(public);
				public = key_new(KEY_UNSPEC);
				if (key_read(public, &cp) != 1) {
					key_free(public);
					continue;
				}
			}
			comment = *cp ? cp : comment;
			fp = key_fingerprint(public, fptype, rep);
			printf("%u %s %s\n", key_size(public), fp,
			    comment ? comment : "no comment");
			xfree(fp);
			key_free(public);
			invalid = 0;
		}
		fclose(f);
	}
	if (invalid) {
		printf("%s is not a public key file.\n", identity_file);
		exit(1);
	}
	exit(0);
}

static void
print_host(FILE *f, char *name, Key *public, int hash)
{
	if (hash && (name = host_hash(name, NULL, 0)) == NULL)
		fatal("hash_host failed");
	fprintf(f, "%s ", name);
	if (!key_write(public, f))
		fatal("key_write failed");
	fprintf(f, "\n");
}

static void
do_known_hosts(struct passwd *pw, const char *name)
{
	FILE *in, *out = stdout;
	Key *public;
	char *cp, *cp2, *kp, *kp2;
	char line[16*1024], tmp[MAXPATHLEN], old[MAXPATHLEN];
	int c, i, skip = 0, inplace = 0, num = 0, invalid = 0, has_unhashed = 0;

	if (!have_identity) {
		cp = tilde_expand_filename(_PATH_SSH_USER_HOSTFILE, pw->pw_uid);
		if (strlcpy(identity_file, cp, sizeof(identity_file)) >=
		    sizeof(identity_file))
			fatal("Specified known hosts path too long");
		xfree(cp);
		have_identity = 1;
	}
	if ((in = fopen(identity_file, "r")) == NULL)
		fatal("fopen: %s", strerror(errno));

	/*
	 * Find hosts goes to stdout, hash and deletions happen in-place
	 * A corner case is ssh-keygen -HF foo, which should go to stdout
	 */
	if (!find_host && (hash_hosts || delete_host)) {
		if (strlcpy(tmp, identity_file, sizeof(tmp)) >= sizeof(tmp) ||
		    strlcat(tmp, ".XXXXXXXXXX", sizeof(tmp)) >= sizeof(tmp) ||
		    strlcpy(old, identity_file, sizeof(old)) >= sizeof(old) ||
		    strlcat(old, ".old", sizeof(old)) >= sizeof(old))
			fatal("known_hosts path too long");
		umask(077);
		if ((c = mkstemp(tmp)) == -1)
			fatal("mkstemp: %s", strerror(errno));
		if ((out = fdopen(c, "w")) == NULL) {
			c = errno;
			unlink(tmp);
			fatal("fdopen: %s", strerror(c));
		}
		inplace = 1;
	}

	while (fgets(line, sizeof(line), in)) {
		num++;
		i = strlen(line) - 1;
		if (line[i] != '\n') {
			error("line %d too long: %.40s...", num, line);
			skip = 1;
			invalid = 1;
			continue;
		}
		if (skip) {
			skip = 0;
			continue;
		}
		line[i] = '\0';

		/* Skip leading whitespace, empty and comment lines. */
		for (cp = line; *cp == ' ' || *cp == '\t'; cp++)
			;
		if (!*cp || *cp == '\n' || *cp == '#') {
			if (inplace)
				fprintf(out, "%s\n", cp);
			continue;
		}
		/* Find the end of the host name portion. */
		for (kp = cp; *kp && *kp != ' ' && *kp != '\t'; kp++)
			;
		if (*kp == '\0' || *(kp + 1) == '\0') {
			error("line %d missing key: %.40s...",
			    num, line);
			invalid = 1;
			continue;
		}
		*kp++ = '\0';
		kp2 = kp;

		public = key_new(KEY_RSA1);
		if (key_read(public, &kp) != 1) {
			kp = kp2;
			key_free(public);
			public = key_new(KEY_UNSPEC);
			if (key_read(public, &kp) != 1) {
				error("line %d invalid key: %.40s...",
				    num, line);
				key_free(public);
				invalid = 1;
				continue;
			}
		}

		if (*cp == HASH_DELIM) {
			if (find_host || delete_host) {
				cp2 = host_hash(name, cp, strlen(cp));
				if (cp2 == NULL) {
					error("line %d: invalid hashed "
					    "name: %.64s...", num, line);
					invalid = 1;
					continue;
				}
				c = (strcmp(cp2, cp) == 0);
				if (find_host && c) {
					printf("# Host %s found: "
					    "line %d type %s\n", name,
					    num, key_type(public));
					print_host(out, cp, public, 0);
				}
				if (delete_host && !c)
					print_host(out, cp, public, 0);
			} else if (hash_hosts)
				print_host(out, cp, public, 0);
		} else {
			if (find_host || delete_host) {
				c = (match_hostname(name, cp,
				    strlen(cp)) == 1);
				if (find_host && c) {
					printf("# Host %s found: "
					    "line %d type %s\n", name,
					    num, key_type(public));
					print_host(out, cp, public, hash_hosts);
				}
				if (delete_host && !c)
					print_host(out, cp, public, 0);
			} else if (hash_hosts) {
				for(cp2 = strsep(&cp, ",");
				    cp2 != NULL && *cp2 != '\0';
				    cp2 = strsep(&cp, ",")) {
					if (strcspn(cp2, "*?!") != strlen(cp2))
						fprintf(stderr, "Warning: "
						    "ignoring host name with "
						    "metacharacters: %.64s\n",
						    cp2);
					else
						print_host(out, cp2, public, 1);
				}
				has_unhashed = 1;
			}
		}
		key_free(public);
	}
	fclose(in);

	if (invalid) {
		fprintf(stderr, "%s is not a valid known_host file.\n",
		    identity_file);
		if (inplace) {
			fprintf(stderr, "Not replacing existing known_hosts "
			    "file beacuse of errors");
			fclose(out);
			unlink(tmp);
		}
		exit(1);
	}

	if (inplace) {
		fclose(out);

		/* Backup existing file */
		if (unlink(old) == -1 && errno != ENOENT)
			fatal("unlink %.100s: %s", old, strerror(errno));
		if (link(identity_file, old) == -1)
			fatal("link %.100s to %.100s: %s", identity_file, old,
			    strerror(errno));
		/* Move new one into place */
		if (rename(tmp, identity_file) == -1) {
			error("rename\"%s\" to \"%s\": %s", tmp, identity_file,
			    strerror(errno));
			unlink(tmp);
			unlink(old);
			exit(1);
		}

		fprintf(stderr, "%s updated.\n", identity_file);
		fprintf(stderr, "Original contents retained as %s\n", old);
		if (has_unhashed) {
			fprintf(stderr, "WARNING: %s contains unhashed "
			    "entries\n", old);
			fprintf(stderr, "Delete this file to ensure privacy "
			     "of hostnames\n");
		}
	}

	exit(0);
}

/*
 * Perform changing a passphrase.  The argument is the passwd structure
 * for the current user.
 */
static void
do_change_passphrase(struct passwd *pw)
{
	char *comment;
	char *old_passphrase, *passphrase1, *passphrase2;
	struct stat st;
	Key *private;

	if (!have_identity)
		ask_filename(pw, "Enter file in which the key is");
	if (stat(identity_file, &st) < 0) {
		perror(identity_file);
		exit(1);
	}
	/* Try to load the file with empty passphrase. */
	private = key_load_private(identity_file, "", &comment);
	if (private == NULL) {
		if (identity_passphrase)
			old_passphrase = xstrdup(identity_passphrase);
		else
			old_passphrase =
			    read_passphrase("Enter old passphrase: ",
			    RP_ALLOW_STDIN);
		private = key_load_private(identity_file, old_passphrase,
		    &comment);
		memset(old_passphrase, 0, strlen(old_passphrase));
		xfree(old_passphrase);
		if (private == NULL) {
			printf("Bad passphrase.\n");
			exit(1);
		}
	}
	printf("Key has comment '%s'\n", comment);

	/* Ask the new passphrase (twice). */
	if (identity_new_passphrase) {
		passphrase1 = xstrdup(identity_new_passphrase);
		passphrase2 = NULL;
	} else {
		passphrase1 =
			read_passphrase("Enter new passphrase (empty for no "
			    "passphrase): ", RP_ALLOW_STDIN);
		passphrase2 = read_passphrase("Enter same passphrase again: ",
		    RP_ALLOW_STDIN);

		/* Verify that they are the same. */
		if (strcmp(passphrase1, passphrase2) != 0) {
			memset(passphrase1, 0, strlen(passphrase1));
			memset(passphrase2, 0, strlen(passphrase2));
			xfree(passphrase1);
			xfree(passphrase2);
			printf("Pass phrases do not match.  Try again.\n");
			exit(1);
		}
		/* Destroy the other copy. */
		memset(passphrase2, 0, strlen(passphrase2));
		xfree(passphrase2);
	}

	/* Save the file using the new passphrase. */
	if (!key_save_private(private, identity_file, passphrase1, comment)) {
		printf("Saving the key failed: %s.\n", identity_file);
		memset(passphrase1, 0, strlen(passphrase1));
		xfree(passphrase1);
		key_free(private);
		xfree(comment);
		exit(1);
	}
	/* Destroy the passphrase and the copy of the key in memory. */
	memset(passphrase1, 0, strlen(passphrase1));
	xfree(passphrase1);
	key_free(private);		 /* Destroys contents */
	xfree(comment);

	printf("Your identification has been saved with the new passphrase.\n");
	exit(0);
}

/*
 * Print the SSHFP RR.
 */
static void
do_print_resource_record(struct passwd *pw, char *hname)
{
	Key *public;
	char *comment = NULL;
	struct stat st;

	if (!have_identity)
		ask_filename(pw, "Enter file in which the key is");
	if (stat(identity_file, &st) < 0) {
		perror(identity_file);
		exit(1);
	}
	public = key_load_public(identity_file, &comment);
	if (public != NULL) {
		export_dns_rr(hname, public, stdout, print_generic);
		key_free(public);
		xfree(comment);
		exit(0);
	}
	if (comment)
		xfree(comment);

	printf("failed to read v2 public key from %s.\n", identity_file);
	exit(1);
}

/*
 * Change the comment of a private key file.
 */
static void
do_change_comment(struct passwd *pw)
{
	char new_comment[1024], *comment, *passphrase;
	Key *private;
	Key *public;
	struct stat st;
	FILE *f;
	int fd;

	if (!have_identity)
		ask_filename(pw, "Enter file in which the key is");
	if (stat(identity_file, &st) < 0) {
		perror(identity_file);
		exit(1);
	}
	private = key_load_private(identity_file, "", &comment);
	if (private == NULL) {
		if (identity_passphrase)
			passphrase = xstrdup(identity_passphrase);
		else if (identity_new_passphrase)
			passphrase = xstrdup(identity_new_passphrase);
		else
			passphrase = read_passphrase("Enter passphrase: ",
			    RP_ALLOW_STDIN);
		/* Try to load using the passphrase. */
		private = key_load_private(identity_file, passphrase, &comment);
		if (private == NULL) {
			memset(passphrase, 0, strlen(passphrase));
			xfree(passphrase);
			printf("Bad passphrase.\n");
			exit(1);
		}
	} else {
		passphrase = xstrdup("");
	}
	if (private->type != KEY_RSA1) {
		fprintf(stderr, "Comments are only supported for RSA1 keys.\n");