Return to signify.c CVS log

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compare snprintf return value with -1. this isn't really necessary because
int promotion rules guarantee the correct result when compared with sizeof,
but it is perhaps easier for some people to understand it this way.
from Doug Hogan.

/* $OpenBSD: signify.c,v 1.91 2014/07/13 18:59:40 tedu Exp $ */
/*
 * Copyright (c) 2013 Ted Unangst <tedu@openbsd.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */
#include <sys/stat.h>

#include <netinet/in.h>
#include <resolv.h>

#include <stdint.h>
#include <fcntl.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <err.h>
#include <unistd.h>
#include <readpassphrase.h>
#include <util.h>
#include <sha2.h>

#include "crypto_api.h"
#ifndef VERIFY_ONLY
#include <stdint.h>
#include <stddef.h>
#include <ohash.h>
#endif

#define SIGBYTES crypto_sign_ed25519_BYTES
#define SECRETBYTES crypto_sign_ed25519_SECRETKEYBYTES
#define PUBLICBYTES crypto_sign_ed25519_PUBLICKEYBYTES

#define PKALG "Ed"
#define KDFALG "BK"
#define FPLEN 8

#define COMMENTHDR "untrusted comment: "
#define COMMENTHDRLEN 19
#define COMMENTMAXLEN 1024
#define VERIFYWITH "verify with "

struct enckey {
	uint8_t pkalg[2];
	uint8_t kdfalg[2];
	uint32_t kdfrounds;
	uint8_t salt[16];
	uint8_t checksum[8];
	uint8_t fingerprint[FPLEN];
	uint8_t seckey[SECRETBYTES];
};

struct pubkey {
	uint8_t pkalg[2];
	uint8_t fingerprint[FPLEN];
	uint8_t pubkey[PUBLICBYTES];
};

struct sig {
	uint8_t pkalg[2];
	uint8_t fingerprint[FPLEN];
	uint8_t sig[SIGBYTES];
};

extern char *__progname;

static void
usage(const char *error)
{
	if (error)
		fprintf(stderr, "%s\n", error);
	fprintf(stderr, "usage:"
#ifndef VERIFYONLY
	    "\t%1$s -C [-q] -p pubkey -x sigfile [file ...]\n"
	    "\t%1$s -G [-n] [-c comment] -p pubkey -s seckey\n"
	    "\t%1$s -I [-p pubkey] [-s seckey] [-x sigfile]\n"
	    "\t%1$s -S [-e] [-x sigfile] -s seckey -m message\n"
#endif
	    "\t%1$s -V [-eq] [-x sigfile] -p pubkey -m message\n",
	    __progname);
	exit(1);
}

static int
xopen(const char *fname, int oflags, mode_t mode)
{
	struct stat sb;
	int fd;

	if (strcmp(fname, "-") == 0) {
		if ((oflags & O_WRONLY))
			fd = dup(STDOUT_FILENO);
		else
			fd = dup(STDIN_FILENO);
		if (fd == -1)
			err(1, "dup failed");
	} else {
		fd = open(fname, oflags, mode);
		if (fd == -1)
			err(1, "can't open %s for %s", fname,
			    (oflags & O_WRONLY) ? "writing" : "reading");
	}
	if (fstat(fd, &sb) == -1 || S_ISDIR(sb.st_mode))
		errx(1, "not a valid file: %s", fname);
	return fd;
}

static void *
xmalloc(size_t len)
{
	void *p;

	if (!(p = malloc(len)))
		err(1, "malloc %zu", len);
	return p;
}

static size_t
parseb64file(const char *filename, char *b64, void *buf, size_t buflen,
    char *comment)
{
	char *commentend, *b64end;

	commentend = strchr(b64, '\n');
	if (!commentend || commentend - b64 <= COMMENTHDRLEN ||
	    memcmp(b64, COMMENTHDR, COMMENTHDRLEN) != 0)
		errx(1, "invalid comment in %s; must start with '%s'",
		    filename, COMMENTHDR);
	*commentend = '\0';
	if (comment) {
		if (strlcpy(comment, b64 + COMMENTHDRLEN,
		    COMMENTMAXLEN) >= COMMENTMAXLEN)
			errx(1, "comment too long");
	}
	if (!(b64end = strchr(commentend + 1, '\n')))
		errx(1, "missing new line after base64 in %s", filename);
	*b64end = '\0';
	if (b64_pton(commentend + 1, buf, buflen) != buflen)
		errx(1, "invalid base64 encoding in %s", filename);
	if (memcmp(buf, PKALG, 2) != 0)
		errx(1, "unsupported file %s", filename);
	return b64end - b64 + 1;
}

static void
readb64file(const char *filename, void *buf, size_t buflen, char *comment)
{
	char b64[2048];
	int rv, fd;

	fd = xopen(filename, O_RDONLY | O_NOFOLLOW, 0);
	if ((rv = read(fd, b64, sizeof(b64) - 1)) == -1)
		err(1, "read from %s", filename);
	b64[rv] = '\0';
	parseb64file(filename, b64, buf, buflen, comment);
	explicit_bzero(b64, sizeof(b64));
	close(fd);
}

static uint8_t *
readmsg(const char *filename, unsigned long long *msglenp)
{
	unsigned long long msglen = 0;
	uint8_t *msg = NULL;
	struct stat sb;
	ssize_t x, space;
	int fd;
	const unsigned long long maxmsgsize = 1UL << 30;

	fd = xopen(filename, O_RDONLY | O_NOFOLLOW, 0);
	if (fstat(fd, &sb) == 0 && S_ISREG(sb.st_mode)) {
		if (sb.st_size > maxmsgsize)
			errx(1, "msg too large in %s", filename);
		space = sb.st_size + 1;
	} else {
		space = 64 * 1024;
	}

	msg = xmalloc(space + 1);
	while (1) {
		if (space == 0) {
			if (msglen * 2 > maxmsgsize)
				errx(1, "msg too large in %s", filename);
			space = msglen;
			if (!(msg = realloc(msg, msglen + space + 1)))
				errx(1, "realloc");
		}
		if ((x = read(fd, msg + msglen, space)) == -1)
			err(1, "read from %s", filename);
		if (x == 0)
			break;
		space -= x;
		msglen += x;
	}

	msg[msglen] = '\0';
	close(fd);

	*msglenp = msglen;
	return msg;
}

static void
writeall(int fd, const void *buf, size_t buflen, const char *filename)
{
	ssize_t x;

	while (buflen != 0) {
		if ((x = write(fd, buf, buflen)) == -1)
			err(1, "write to %s", filename);
		buflen -= x;
		buf = (char *)buf + x;
	}
}

#ifndef VERIFYONLY
static void
writeb64file(const char *filename, const char *comment, const void *buf,
    size_t buflen, const void *msg, size_t msglen, int oflags, mode_t mode)
{
	char header[1024];
	char b64[1024];
	int fd, rv, nr;

	fd = xopen(filename, O_CREAT|oflags|O_NOFOLLOW|O_WRONLY, mode);
	if ((nr = snprintf(header, sizeof(header), "%s%s\n",
	    COMMENTHDR, comment)) == -1 || nr >= sizeof(header))
		errx(1, "comment too long");
	writeall(fd, header, strlen(header), filename);
	if ((rv = b64_ntop(buf, buflen, b64, sizeof(b64)-1)) == -1)
		errx(1, "base64 encode failed");
	b64[rv++] = '\n';
	writeall(fd, b64, rv, filename);
	explicit_bzero(b64, sizeof(b64));
	if (msg)
		writeall(fd, msg, msglen, filename);
	close(fd);
}

static void
kdf(uint8_t *salt, size_t saltlen, int rounds, int allowstdin, int confirm,
    uint8_t *key, size_t keylen)
{
	char pass[1024];
	int rppflags = RPP_ECHO_OFF;

	if (rounds == 0) {
		memset(key, 0, keylen);
		return;
	}

	if (allowstdin && !isatty(STDIN_FILENO))
		rppflags |= RPP_STDIN;
	if (!readpassphrase("passphrase: ", pass, sizeof(pass), rppflags))
		errx(1, "unable to read passphrase");
	if (strlen(pass) == 0)
		errx(1, "please provide a password");
	if (confirm && !(rppflags & RPP_STDIN)) {
		char pass2[1024];
		if (!readpassphrase("confirm passphrase: ", pass2,
		    sizeof(pass2), rppflags))
			errx(1, "unable to read passphrase");
		if (strcmp(pass, pass2) != 0)
			errx(1, "passwords don't match");
		explicit_bzero(pass2, sizeof(pass2));
	}
	if (bcrypt_pbkdf(pass, strlen(pass), salt, saltlen, key,
	    keylen, rounds) == -1)
		errx(1, "bcrypt pbkdf");
	explicit_bzero(pass, sizeof(pass));
}

static void
signmsg(uint8_t *seckey, uint8_t *msg, unsigned long long msglen,
    uint8_t *sig)
{
	unsigned long long siglen;
	uint8_t *sigbuf;

	sigbuf = xmalloc(msglen + SIGBYTES);
	crypto_sign_ed25519(sigbuf, &siglen, msg, msglen, seckey);
	memcpy(sig, sigbuf, SIGBYTES);
	free(sigbuf);
}

static void
generate(const char *pubkeyfile, const char *seckeyfile, int rounds,
    const char *comment)
{
	uint8_t digest[SHA512_DIGEST_LENGTH];
	struct pubkey pubkey;
	struct enckey enckey;
	uint8_t xorkey[sizeof(enckey.seckey)];
	uint8_t fingerprint[FPLEN];
	char commentbuf[COMMENTMAXLEN];
	SHA2_CTX ctx;
	int i, nr;

	crypto_sign_ed25519_keypair(pubkey.pubkey, enckey.seckey);
	arc4random_buf(fingerprint, sizeof(fingerprint));

	SHA512Init(&ctx);
	SHA512Update(&ctx, enckey.seckey, sizeof(enckey.seckey));
	SHA512Final(digest, &ctx);

	memcpy(enckey.pkalg, PKALG, 2);
	memcpy(enckey.kdfalg, KDFALG, 2);
	enckey.kdfrounds = htonl(rounds);
	memcpy(enckey.fingerprint, fingerprint, FPLEN);
	arc4random_buf(enckey.salt, sizeof(enckey.salt));
	kdf(enckey.salt, sizeof(enckey.salt), rounds, 1, 1, xorkey, sizeof(xorkey));
	memcpy(enckey.checksum, digest, sizeof(enckey.checksum));
	for (i = 0; i < sizeof(enckey.seckey); i++)
		enckey.seckey[i] ^= xorkey[i];
	explicit_bzero(digest, sizeof(digest));
	explicit_bzero(xorkey, sizeof(xorkey));

	if ((nr = snprintf(commentbuf, sizeof(commentbuf), "%s secret key",
	    comment)) == -1 || nr >= sizeof(commentbuf))
		errx(1, "comment too long");
	writeb64file(seckeyfile, commentbuf, &enckey,
	    sizeof(enckey), NULL, 0, O_EXCL, 0600);
	explicit_bzero(&enckey, sizeof(enckey));

	memcpy(pubkey.pkalg, PKALG, 2);
	memcpy(pubkey.fingerprint, fingerprint, FPLEN);
	if ((nr = snprintf(commentbuf, sizeof(commentbuf), "%s public key",
	    comment)) == -1 || nr >= sizeof(commentbuf))
		errx(1, "comment too long");
	writeb64file(pubkeyfile, commentbuf, &pubkey,
	    sizeof(pubkey), NULL, 0, O_EXCL, 0666);
}

static void
sign(const char *seckeyfile, const char *msgfile, const char *sigfile,
    int embedded)
{
	struct sig sig;
	uint8_t digest[SHA512_DIGEST_LENGTH];
	struct enckey enckey;
	uint8_t xorkey[sizeof(enckey.seckey)];
	uint8_t *msg;
	char comment[COMMENTMAXLEN], sigcomment[COMMENTMAXLEN];
	char *secname;
	unsigned long long msglen;
	int i, rounds, nr;
	SHA2_CTX ctx;

	readb64file(seckeyfile, &enckey, sizeof(enckey), comment);

	if (memcmp(enckey.kdfalg, KDFALG, 2) != 0)
		errx(1, "unsupported KDF");
	rounds = ntohl(enckey.kdfrounds);
	kdf(enckey.salt, sizeof(enckey.salt), rounds, strcmp(msgfile, "-") != 0,
	    0, xorkey, sizeof(xorkey));
	for (i = 0; i < sizeof(enckey.seckey); i++)
		enckey.seckey[i] ^= xorkey[i];
	explicit_bzero(xorkey, sizeof(xorkey));
	SHA512Init(&ctx);
	SHA512Update(&ctx, enckey.seckey, sizeof(enckey.seckey));
	SHA512Final(digest, &ctx);
	if (memcmp(enckey.checksum, digest, sizeof(enckey.checksum)) != 0)
	    errx(1, "incorrect passphrase");
	explicit_bzero(digest, sizeof(digest));

	msg = readmsg(msgfile, &msglen);

	signmsg(enckey.seckey, msg, msglen, sig.sig);
	memcpy(sig.fingerprint, enckey.fingerprint, FPLEN);
	explicit_bzero(&enckey, sizeof(enckey));

	memcpy(sig.pkalg, PKALG, 2);
	secname = strstr(seckeyfile, ".sec");
	if (secname && strlen(secname) == 4) {
		if ((nr = snprintf(sigcomment, sizeof(sigcomment), VERIFYWITH "%.*s.pub",
		    (int)strlen(seckeyfile) - 4, seckeyfile)) == -1 || nr >= sizeof(sigcomment))
			errx(1, "comment too long");
	} else {
		if ((nr = snprintf(sigcomment, sizeof(sigcomment), "signature from %s",
		    comment)) == -1 || nr >= sizeof(sigcomment))
			errx(1, "comment too long");
	}
	if (embedded)
		writeb64file(sigfile, sigcomment, &sig, sizeof(sig), msg,
		    msglen, O_TRUNC, 0666);
	else
		writeb64file(sigfile, sigcomment, &sig, sizeof(sig), NULL,
		    0, O_TRUNC, 0666);

	free(msg);
}

static void
inspect(const char *seckeyfile, const char *pubkeyfile, const char *sigfile)
{
	struct sig sig;
	struct enckey enckey;
	struct pubkey pubkey;
	char fp[(FPLEN + 2) / 3 * 4 + 1];

	if (seckeyfile) {
		readb64file(seckeyfile, &enckey, sizeof(enckey), NULL);
		b64_ntop(enckey.fingerprint, FPLEN, fp, sizeof(fp));
		printf("sec fp: %s\n", fp);
	}
	if (pubkeyfile) {
		readb64file(pubkeyfile, &pubkey, sizeof(pubkey), NULL);
		b64_ntop(pubkey.fingerprint, FPLEN, fp, sizeof(fp));
		printf("pub fp: %s\n", fp);
	}
	if (sigfile) {
		readb64file(sigfile, &sig, sizeof(sig), NULL);
		b64_ntop(sig.fingerprint, FPLEN, fp, sizeof(fp));
		printf("sig fp: %s\n", fp);
	}
}
#endif

static void
verifymsg(struct pubkey *pubkey, uint8_t *msg, unsigned long long msglen,
    struct sig *sig, int quiet)
{
	uint8_t *sigbuf, *dummybuf;
	unsigned long long siglen, dummylen;

	if (memcmp(pubkey->fingerprint, sig->fingerprint, FPLEN) != 0)
		errx(1, "verification failed: checked against wrong key");

	siglen = SIGBYTES + msglen;
	sigbuf = xmalloc(siglen);
	dummybuf = xmalloc(siglen);
	memcpy(sigbuf, sig->sig, SIGBYTES);
	memcpy(sigbuf + SIGBYTES, msg, msglen);
	if (crypto_sign_ed25519_open(dummybuf, &dummylen, sigbuf, siglen,
	    pubkey->pubkey) == -1)
		errx(1, "signature verification failed");
	if (!quiet)
		printf("Signature Verified\n");
	free(sigbuf);
	free(dummybuf);
}

static void
readpubkey(const char *pubkeyfile, struct pubkey *pubkey,
    const char *sigcomment)
{
	const char *safepath = "/etc/signify/";

	if (!pubkeyfile) {
		pubkeyfile = strstr(sigcomment, VERIFYWITH);
		if (pubkeyfile) {
			pubkeyfile += strlen(VERIFYWITH);
			if (strncmp(pubkeyfile, safepath, strlen(safepath)) != 0 ||
			    strstr(pubkeyfile, "/../") != NULL)
				errx(1, "untrusted path %s", pubkeyfile);
		} else
			usage("must specify pubkey");
	}
	readb64file(pubkeyfile, pubkey, sizeof(*pubkey), NULL);
}

static void
verifysimple(const char *pubkeyfile, const char *msgfile, const char *sigfile,
    int quiet)
{
	char sigcomment[COMMENTMAXLEN];
	struct sig sig;
	struct pubkey pubkey;
	unsigned long long msglen;
	uint8_t *msg;

	msg = readmsg(msgfile, &msglen);

	readb64file(sigfile, &sig, sizeof(sig), sigcomment);
	readpubkey(pubkeyfile, &pubkey, sigcomment);

	verifymsg(&pubkey, msg, msglen, &sig, quiet);

	free(msg);
}

static uint8_t *
verifyembedded(const char *pubkeyfile, const char *sigfile,
    int quiet, unsigned long long *msglenp)
{
	char sigcomment[COMMENTMAXLEN];
	struct sig sig;
	struct pubkey pubkey;
	unsigned long long msglen, siglen;
	uint8_t *msg;

	msg = readmsg(sigfile, &msglen);

	siglen = parseb64file(sigfile, msg, &sig, sizeof(sig), sigcomment);
	readpubkey(pubkeyfile, &pubkey, sigcomment);

	msglen -= siglen;
	memmove(msg, msg + siglen, msglen);
	msg[msglen] = 0;

	verifymsg(&pubkey, msg, msglen, &sig, quiet);

	*msglenp = msglen;
	return msg;
}

static void
verify(const char *pubkeyfile, const char *msgfile, const char *sigfile,
    int embedded, int quiet)
{
	unsigned long long msglen;
	uint8_t *msg;
	int fd;

	if (embedded) {
		msg = verifyembedded(pubkeyfile, sigfile, quiet, &msglen);
		fd = xopen(msgfile, O_CREAT|O_TRUNC|O_NOFOLLOW|O_WRONLY, 0666);
		writeall(fd, msg, msglen, msgfile);
		free(msg);
		close(fd);
	} else {
		verifysimple(pubkeyfile, msgfile, sigfile, quiet);
	}
}

#ifndef VERIFYONLY
#define HASHBUFSIZE 224
struct checksum {
	char file[1024];
	char hash[HASHBUFSIZE];
	char algo[32];
};

static void * 
ecalloc(size_t s1, size_t s2, void *data)
{
	void *p;

	if (!(p = calloc(s1, s2)))
		err(1, "calloc");
	return p;
}

static void
efree(void *p, void *data)
{
	free(p);
}

static void
recodehash(char *hash, size_t len)
{
	uint8_t data[HASHBUFSIZE / 2];
	int i, rv;

	if (strlen(hash) == len)
		return;
	if ((rv = b64_pton(hash, data, sizeof(data))) == -1)
		errx(1, "invalid base64 encoding");
	for (i = 0; i < rv; i++)
		snprintf(hash + i * 2, HASHBUFSIZE - i * 2, "%2.2x", data[i]);
}

static int
verifychecksum(struct checksum *c, int quiet)
{
	char buf[HASHBUFSIZE];

	if (strcmp(c->algo, "SHA256") == 0) {
		recodehash(c->hash, SHA256_DIGEST_STRING_LENGTH-1);
		if (!SHA256File(c->file, buf))
			return 0;
	} else if (strcmp(c->algo, "SHA512") == 0) {
		recodehash(c->hash, SHA512_DIGEST_STRING_LENGTH-1);
		if (!SHA512File(c->file, buf))
			return 0;
	} else {
		errx(1, "can't handle algorithm %s", c->algo);
	}
	if (strcmp(c->hash, buf) != 0) {
		return 0;
	}
	if (!quiet)
		printf("%s: OK\n", c->file);
	return 1;
}

static void
verifychecksums(char *msg, int argc, char **argv, int quiet)
{
	struct ohash_info info = { 0, NULL, ecalloc, efree, NULL };
	struct ohash myh;
	struct checksum c;
	char *e, *line, *endline;
	int hasfailed = 0;
	int i, rv;
	unsigned int slot;

	ohash_init(&myh, 6, &info);
	if (argc) {
		for (i = 0; i < argc; i++) {
			slot = ohash_qlookup(&myh, argv[i]);
			e = ohash_find(&myh, slot);
			if (e == NULL)
				ohash_insert(&myh, slot, argv[i]);
		}
	}

	line = msg;
	while (line && *line) {
		if ((endline = strchr(line, '\n')))
			*endline++ = '\0';
		rv = sscanf(line, "%31s (%1023s = "3s",
		    c.algo, c.file, c.hash);
		if (rv != 3 || c.file[0] == 0 || c.file[strlen(c.file)-1] != ')')
			errx(1, "unable to parse checksum line %s", line);
		c.file[strlen(c.file) - 1] = '\0';
		line = endline;
		if (argc) {
			slot = ohash_qlookup(&myh, c.file);
			e = ohash_find(&myh, slot);
			if (e != NULL) {
				if (verifychecksum(&c, quiet) != 0)
					ohash_remove(&myh, slot);
			}
		} else {
			if (verifychecksum(&c, quiet) == 0) {
				slot = ohash_qlookup(&myh, c.file);
				e = ohash_find(&myh, slot);
				if (e == NULL) {
					if (!(e = strdup(c.file)))
						err(1, "strdup");
					ohash_insert(&myh, slot, e);
				}
			}
		}
	}

	for (e = ohash_first(&myh, &slot); e != NULL; e = ohash_next(&myh, &slot)) {
		fprintf(stderr, "%s: FAIL\n", e);
		hasfailed = 1;
		if (argc == 0)
			free(e);
	}
	ohash_delete(&myh);
	if (hasfailed)
		exit(1);
}

static void
check(const char *pubkeyfile, const char *sigfile, int quiet, int argc,
    char **argv)
{
	unsigned long long msglen;
	uint8_t *msg;

	msg = verifyembedded(pubkeyfile, sigfile, quiet, &msglen);
	verifychecksums((char *)msg, argc, argv, quiet);

	free(msg);
}
#endif

int
main(int argc, char **argv)
{
	const char *pubkeyfile = NULL, *seckeyfile = NULL, *msgfile = NULL,
	    *sigfile = NULL;
	char sigfilebuf[1024];
	const char *comment = "signify";
	int ch, rounds;
	int embedded = 0;
	int quiet = 0;
	enum {
		NONE,
		CHECK,
		GENERATE,
		INSPECT,
		SIGN,
		VERIFY
	} verb = NONE;


	rounds = 42;

	while ((ch = getopt(argc, argv, "CGISVc:em:np:qs:x:")) != -1) {
		switch (ch) {
#ifndef VERIFYONLY
		case 'C':
			if (verb)
				usage(NULL);
			verb = CHECK;
			break;
		case 'G':
			if (verb)
				usage(NULL);
			verb = GENERATE;
			break;
		case 'I':
			if (verb)
				usage(NULL);
			verb = INSPECT;
			break;
		case 'S':
			if (verb)
				usage(NULL);
			verb = SIGN;
			break;
#endif
		case 'V':
			if (verb)
				usage(NULL);
			verb = VERIFY;
			break;
		case 'c':
			comment = optarg;
			break;
		case 'e':
			embedded = 1;
			break;
		case 'm':
			msgfile = optarg;
			break;
		case 'n':
			rounds = 0;
			break;
		case 'p':
			pubkeyfile = optarg;
			break;
		case 'q':
			quiet = 1;
			break;
		case 's':
			seckeyfile = optarg;
			break;
		case 'x':
			sigfile = optarg;
			break;
		default:
			usage(NULL);
			break;
		}
	}
	argc -= optind;
	argv += optind;

#ifndef VERIFYONLY
	if (verb == CHECK) {
		if (!sigfile)
			usage("must specify sigfile");
		check(pubkeyfile, sigfile, quiet, argc, argv);
		return 0;
	}
#endif

	if (argc != 0)
		usage(NULL);

	if (!sigfile && msgfile) {
		int nr;
		if (strcmp(msgfile, "-") == 0)
			usage("must specify sigfile with - message");
		if ((nr = snprintf(sigfilebuf, sizeof(sigfilebuf), "%s.sig",
		    msgfile)) == -1 || nr >= sizeof(sigfilebuf))
			errx(1, "path too long");
		sigfile = sigfilebuf;
	}

	switch (verb) {
#ifndef VERIFYONLY
	case GENERATE:
		if (!pubkeyfile || !seckeyfile)
			usage("must specify pubkey and seckey");
		generate(pubkeyfile, seckeyfile, rounds, comment);
		break;
	case INSPECT:
		inspect(seckeyfile, pubkeyfile, sigfile);
		break;
	case SIGN:
		if (!msgfile || !seckeyfile)
			usage("must specify message and seckey");
		sign(seckeyfile, msgfile, sigfile, embedded);
		break;
#endif
	case VERIFY:
		if (!msgfile)
			usage("must specify message");
		verify(pubkeyfile, msgfile, sigfile, embedded, quiet);
		break;
	default:
		usage(NULL);
		break;
	}

	return 0;
}