Add set -e.

[catacomb] / dsig.c

/* -*-c-*-
 *
 * $Id: dsig.c,v 1.8 2004/04/04 19:42:59 mdw Exp $
 *
 * Verify signatures on distribuitions of files
 *
 * (c) 2000 Straylight/Edgeware
 */

/*----- Licensing notice --------------------------------------------------* 
 *
 * This file is part of Catacomb.
 *
 * Catacomb is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Library General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 * 
 * Catacomb is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Library General Public License for more details.
 * 
 * You should have received a copy of the GNU Library General Public
 * License along with Catacomb; if not, write to the Free
 * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
 * MA 02111-1307, USA.
 */

/*----- Revision history --------------------------------------------------* 
 *
 * $Log: dsig.c,v $
 * Revision 1.8  2004/04/04 19:42:59  mdw
 * Add set -e.
 *
 * Revision 1.7  2001/02/23 09:04:17  mdw
 * Add new hash functions.  Provide full help for subcommands.  Run the
 * hash function over parts of the header in a canonical order.
 *
 * Revision 1.6  2000/12/06 20:33:27  mdw
 * Make flags be macros rather than enumerations, to ensure that they're
 * unsigned.
 *
 * Revision 1.5  2000/10/08 12:12:09  mdw
 * Shut up some warnings.
 *
 * Revision 1.4  2000/08/04 23:23:44  mdw
 * Various <ctype.h> fixes.
 *
 * Revision 1.3  2000/07/15 20:53:23  mdw
 * More hash functions.  Bug fix in getstring.
 *
 * Revision 1.2  2000/07/01 11:27:22  mdw
 * Use new PKCS#1 padding functions rather than rolling by hand.
 *
 * Revision 1.1  2000/06/17 10:54:29  mdw
 * Program to generate and verify signatures on multiple files.
 *
 */

/*----- Header files ------------------------------------------------------*/

#include "config.h"

#include <ctype.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <mLib/alloc.h>
#include <mLib/base64.h>
#include <mLib/mdwopt.h>
#include <mLib/quis.h>
#include <mLib/report.h>
#include <mLib/sub.h>

#include "getdate.h"
#include "grand.h"
#include "ghash.h"
#include "key.h"
#include "key-data.h"
#include "noise.h"

#include "dsa.h"
#include "rsa.h"
#include "pkcs1.h"

/*----- Digital signature algorithm ---------------------------------------*/

static int dsasign(key *k, const void *m, size_t msz, dstr *d)
{
  dsa_priv dp;
  key_packstruct ks[DSA_PRIVFETCHSZ];
  key_packdef *kp;
  size_t sz;
  octet *p;
  int e;

  kp = key_fetchinit(dsa_privfetch, ks, &dp);
  if ((e = key_fetch(kp, k)) != 0) {
    key_fetchdone(kp);
    return (e);
  }
  sz = mp_octets(dp.dp.q);
  if (sz < msz)
    die(EXIT_FAILURE, "hash function too wide for this signing key");
  DENSURE(d, sz * 2);
  p = (octet *)d->buf + d->len;
  rand_get(RAND_GLOBAL, p, sz);
  dsa_sign(&dp.dp, dp.x, m, msz, p, sz, p, sz, p + sz, sz);
  d->len += sz * 2;
  key_fetchdone(kp);
  return (0);
}

static int dsaverify(key *k, const void *m, size_t msz,
		     const void *s, size_t ssz)
{
  dsa_pub dp;
  key_packstruct ks[DSA_PUBFETCHSZ];
  key_packdef *kp;
  size_t sz;
  const octet *p = s;
  int e;

  kp = key_fetchinit(dsa_pubfetch, ks, &dp);
  if ((e = key_fetch(kp, k)) != 0) {
    key_fetchdone(kp);
    return (e);
  }
  sz = ssz / 2;
  e = dsa_verify(&dp.dp, dp.y, m, msz, p, sz, p + sz, sz);
  key_fetchdone(kp);
  return (e);  
}

/*----- RSA signing -------------------------------------------------------*/

static int rsasign(key *k, const void *m, size_t msz, dstr *d)
{
  rsa_priv rp;
  rsa_privctx rpc;
  pkcs1 pk = { 0, 0, 0 };
  key_packstruct ks[RSA_PRIVFETCHSZ];
  key_packdef *kp;
  int e;

  kp = key_fetchinit(rsa_privfetch, ks, &rp);
  if ((e = key_fetch(kp, k)) != 0) {
    key_fetchdone(kp);
    return (e);
  }
  rsa_privcreate(&rpc, &rp, &rand_global);
  if (rsa_sign(&rpc, m, msz, d, pkcs1_sigencode, &pk) < 0)
    die(EXIT_FAILURE, "internal error in rsasign (key too small?)");
  rsa_privdestroy(&rpc);
  key_fetchdone(kp);
  return (0);
}

static int rsaverify(key *k, const void *m, size_t msz,
		     const void *s, size_t ssz)
{
  rsa_pub rp;
  rsa_pubctx rpc;
  pkcs1 pk = { 0, 0, 0 };
  key_packstruct ks[RSA_PUBFETCHSZ];
  key_packdef *kp;
  int ok = 0;
  dstr d = DSTR_INIT;
  int e;

  kp = key_fetchinit(rsa_pubfetch, ks, &rp);
  if ((e = key_fetch(kp, k)) != 0) {
    key_fetchdone(kp);
    return (e);
  }
  rsa_pubcreate(&rpc, &rp);
  if (rsa_verify(&rpc, s, ssz, &d, pkcs1_sigdecode, &pk) > 0 &&
      msz == d.len && memcmp(d.buf, m, msz) == 0)
    ok = 1;
  dstr_destroy(&d);
  rsa_pubdestroy(&rpc);
  key_fetchdone(kp);
  return (ok);
}  

/*----- Algorithm choice --------------------------------------------------*/

typedef struct sig {
  const char *name;
  const char *type;
  int (*sign)(key */*k*/, const void */*m*/, size_t /*msz*/, dstr */*d*/);
  int (*verify)(key */*k*/, const void */*m*/, size_t /*msz*/,
		const void */*s*/, size_t /*ssz*/);
} sig;

static sig sigtab[] = {
  { "dsa", "dsig-dsa", dsasign, dsaverify },
  { "rsa", "dsig-rsa", rsasign, rsaverify },
  { 0, 0, 0 }
};

/* --- @gethash@ --- *
 *
 * Arguments:	@const char *name@ = pointer to name string
 *
 * Returns:	Pointer to appropriate hash class.
 *
 * Use:		Chooses a hash function by name.
 */

static const gchash *gethash(const char *name)
{
  const gchash *const *g, *gg = 0;
  size_t sz = strlen(name);
  for (g = ghashtab; *g; g++) {
    if (strncmp(name, (*g)->name, sz) == 0) {
      if ((*g)->name[sz] == 0) {
	gg = *g;
	break;
      } else if (gg)
	return (0);
      else
	gg = *g;
    }
  }
  return (gg);
}

/* --- @getsig@ --- *
 *
 * Arguments:	@const char *name@ = pointer to name string
 *
 * Returns:	Pointer to appropriate signature type.
 *
 * Use:		Chooses a signature algorithm by name.
 */

static sig *getsig(const char *name)
{
  sig *s, *ss = 0;
  size_t sz = strlen(name);
  for (s = sigtab; s->name; s++) {
    if (strncmp(name, s->name, sz) == 0) {
      if (s->name[sz] == 0) {
	ss = s;
	break;
      } else if (ss)
	return (0);
      else
	ss = s;
    }
  }
  return (ss);
}

/*----- Data formatting ---------------------------------------------------*/

/* --- Binary data structure --- *
 *
 * The binary format, which is used for hashing and for the optional binary
 * output, consists of a sequence of tagged blocks.  The tag describes the
 * format and meaining of the following data.
 */

enum {
  /* --- Block tags --- */

  T_IDENT = 0,				/* An identifying marker */
  T_SIGALG,				/* Signature algorithm used */
  T_HASHALG,				/* Hash algorithm used */
  T_KEYID,				/* Key identifier */
  T_BEGIN,				/* Begin hashing here */
  T_COMMENT = T_BEGIN,			/* A textual comment */
  T_DATE,				/* Creation date of signature */
  T_EXPIRE,				/* Expiry date of signature */
  T_FILE,				/* File and corresponding hash */
  T_SIGNATURE,				/* Final signature block */

  /* --- Error messages --- */

  E_EOF = -1,
  E_BIN = -2,
  E_TAG = -3,
  E_DATE = -4
};

/* --- Name translation table --- */

static const char *tagtab[] = {
  "ident:", "sigalg:", "hashalg:", "keyid:",
  "comment:", "date:", "expires:", "file:",
  "signature:",
  0
};

static const char *errtab[] = {
  "Off-by-one bug",
  "Unexpected end-of-file",
  "Binary object too large",
  "Unrecognized tag",
  "Bad date string"
};

/* --- Memory representation of block types --- */

typedef struct block {
  int tag;				/* Type tag */
  dstr d;				/* String data */
  dstr b;				/* Binary data */
  time_t t;				/* Timestamp */
  uint32 k;				/* Keyid */
} block;

/* --- @getstring@ --- *
 *
 * Arguments:	@FILE *fp@ = stream from which to read
 *		@dstr *d@ = destination string
 *		@unsigned raw@ = raw or cooked read
 *
 * Returns:	Zero if OK, nonzero on end-of-file.
 *
 * Use:		Reads a filename (or something similar) from a stream.
 */

static int getstring(FILE *fp, dstr *d, unsigned raw)
{
  int ch;
  int q = 0;

  /* --- Raw: just read exactly what's written up to a null byte --- */

  if (raw) {
    if ((ch = getc(fp)) == EOF)
      return (EOF);
    for (;;) {
      if (!ch)
	break;
      DPUTC(d, ch);
      if ((ch = getc(fp)) == EOF)
	break;
    }
    DPUTZ(d);
    return (0);
  }

  /* --- Skip as far as whitespace --- *
   *
   * Also skip past comments.
   */

again:
  ch = getc(fp);
  while (isspace(ch))
    ch = getc(fp);
  if (ch == '#') {
    do ch = getc(fp); while (ch != '\n' && ch != EOF);
    goto again;
  }
  if (ch == EOF)
    return (EOF);

  /* --- If the character is a quote then read a quoted string --- */

  switch (ch) {
    case '`':
      ch = '\'';
    case '\'':
    case '\"':
      q = ch;
      ch = getc(fp);
      break;
  }

  /* --- Now read all sorts of interesting things --- */

  for (;;) {

    /* --- Handle an escaped thing --- */

    if (ch == '\\') {
      ch = getc(fp);
      if (ch == EOF)
	break;
      switch (ch) {
	case 'a': ch = '\a'; break;
	case 'b': ch = '\b'; break;
	case 'f': ch = '\f'; break;
	case 'n': ch = '\n'; break;
	case 'r': ch = '\r'; break;
	case 't': ch = '\t'; break;
	case 'v': ch = '\v'; break;
      }
      DPUTC(d, ch);
      ch = getc(fp);
      continue;
    }

    /* --- If it's a quote or some other end marker then stop --- */

    if (ch == q || (!q && isspace((unsigned char)ch)))
      break;

    /* --- Otherwise contribute and continue --- */

    DPUTC(d, ch);
    if ((ch = getc(fp)) == EOF)
      break;
  }

  /* --- Done --- */

  DPUTZ(d);
  return (0);
}

/* --- @putstring@ --- *
 *
 * Arguments:	@FILE *fp@ = stream to write on
 *		@const char *p@ = pointer to text
 *		@unsigned raw@ = whether the string is to be written raw
 *
 * Returns:	---
 *
 * Use:		Emits a string to a stream.
 */

static void putstring(FILE *fp, const char *p, unsigned raw)
{
  size_t sz = strlen(p);
  unsigned qq;
  const char *q;

  /* --- Just write the string null terminated if raw --- */

  if (raw) {
    fwrite(p, 1, sz + 1, fp);
    return;
  }

  /* --- Check for any dodgy characters --- */

  qq = 0;
  for (q = p; *q; q++) {
    if (isspace((unsigned char)*q)) {
      qq = '\"';
      break;
    }
  }

  if (qq)
    putc(qq, fp);

  /* --- Emit the string --- */

  for (q = p; *q; q++) {
    switch (*q) {
      case '\a': fputc('\\', fp); fputc('a', fp); break;
      case '\b': fputc('\\', fp); fputc('b', fp); break;
      case '\f': fputc('\\', fp); fputc('f', fp); break;
      case '\n': fputc('\\', fp); fputc('n', fp); break;
      case '\r': fputc('\\', fp); fputc('r', fp); break;
      case '\t': fputc('\\', fp); fputc('t', fp); break;
      case '\v': fputc('\\', fp); fputc('v', fp); break;
      case '`': fputc('\\', fp); fputc('`', fp); break;
      case '\'': fputc('\\', fp); fputc('\'', fp); break;
      case '\"': fputc('\\', fp); fputc('\"', fp); break;
      default:
	putc(*q, fp);
	break;
    }
  }

  /* --- Done --- */

  if (qq)
    putc(qq, fp);
}

/* --- @timestring@ --- *
 *
 * Arguments:	@time_t t@ = a timestamp
 *		@dstr *d@ = a string to write on
 *
 * Returns:	---
 *
 * Use:		Writes a textual representation of the timestamp to the
 *		string.
 */

static void timestring(time_t t, dstr *d)
{
  if (t == KEXP_FOREVER)
    DPUTS(d, "forever");
  else {
    struct tm *tm = localtime(&t);
    DENSURE(d, 32);
    d->len += strftime(d->buf + d->len, 32, "%Y-%m-%d %H:%M:%S %Z", tm);
    DPUTZ(d);
  }
}

/* --- @breset@ --- *
 *
 * Arguments:	@block *b@ = block to reset
 *
 * Returns:	---
 *
 * Use:		Resets a block so that more stuff can be put in it.
 */

static void breset(block *b)
{
  b->tag = 0;
  DRESET(&b->d);
  DRESET(&b->b);
  b->k = 0;
  b->t = KEXP_EXPIRE;
}

/* --- @binit@ --- *
 *
 * Arguments:	@block *b@ = block to initialize
 *
 * Returns:	---
 *
 * Use:		Initializes a block as something to read into.
 */

static void binit(block *b)
{
  dstr_create(&b->d);
  dstr_create(&b->b);
  breset(b);
}

/* --- @bdestroy@ --- *
 *
 * Arguments:	@block *b@ = block to destroy
 *
 * Returns:	---
 *
 * Use:		Destroys a block's contents.
 */

static void bdestroy(block *b)
{
  dstr_destroy(&b->d);
  dstr_destroy(&b->b);
}

/* --- @bget@ --- *
 *
 * Arguments:	@block *b@ = pointer to block
 *		@FILE *fp@ = stream to read from
 *		@unsigned bin@ = binary switch
 *
 * Returns:	Tag of block, or an error tag.
 *
 * Use:		Reads a block from a stream.
 */

static int bget(block *b, FILE *fp, unsigned bin)
{
  int tag;

  /* --- Read the tag --- */

  if (bin)
    tag = getc(fp);
  else {
    dstr d = DSTR_INIT;
    if (getstring(fp, &d, 0))
      return (E_EOF);
    for (tag = 0; tagtab[tag]; tag++) {
      if (strcmp(tagtab[tag], d.buf) == 0)
	goto done;
    }
    return (E_TAG);
  done:;
  }

  /* --- Decide what to do next --- */

  breset(b);
  b->tag = tag;
  switch (tag) {

    /* --- Reading of strings --- */

    case T_IDENT:
    case T_COMMENT:
    case T_SIGALG:
    case T_HASHALG:
      if (getstring(fp, &b->d, bin))
	return (E_EOF);
      break;

    /* --- Timestamps --- */

    case T_DATE:
    case T_EXPIRE:
      if (bin) {
	octet buf[8];
	if (fread(buf, sizeof(buf), 1, fp) < 1)
	  return (E_EOF);
	b->t = ((time_t)(((LOAD32(buf + 0) << 16) << 16) & ~MASK32) |
		(time_t)LOAD32(buf + 4));
      } else {
	if (getstring(fp, &b->d, 0))
	  return (E_EOF);
	if (strcmp(b->d.buf, "forever") == 0)
	  b->t = KEXP_FOREVER;
	else if ((b->t = get_date(b->d.buf, 0)) == -1)
	  return (E_DATE);
      }
      break;

    /* --- Key ids --- */

    case T_KEYID:
      if (bin) {
	octet buf[4];
	if (fread(buf, sizeof(buf), 1, fp) < 1)
	  return (E_EOF);
	b->k = LOAD32(buf);
      } else {
	if (getstring(fp, &b->d, 0))
	  return (E_EOF);
	b->k = strtoul(b->d.buf, 0, 16);
      }
      break;

    /* --- Reading of binary data --- */

    case T_FILE:
    case T_SIGNATURE:
      if (bin) {
	octet buf[2];
	uint32 sz;
	if (fread(buf, sizeof(buf), 1, fp) < 1)
	  return (E_EOF);
	sz = LOAD16(buf);
	if (sz > 4096)
	  return (E_BIN);
	DENSURE(&b->b, sz);
	if (fread(b->b.buf + b->b.len, 1, sz, fp) < sz)
	  return (E_EOF);
	b->b.len += sz;
      } else {
	base64_ctx b64;
	if (getstring(fp, &b->d, 0))
	  return (E_EOF);
	base64_init(&b64);
	base64_decode(&b64, b->d.buf, b->d.len, &b->b);
	base64_decode(&b64, 0, 0, &b->b);
	DRESET(&b->d);
      }
      if (tag == T_FILE && getstring(fp, &b->d, bin))
	return (E_EOF);
      break;

      /* --- Anything else --- */

    default:
      return (E_TAG);
  }

  return (tag);
}

/* --- @blob@ --- *
 *
 * Arguments:	@block *b@ = pointer to block to emit
 *		@dstr *d@ = output buffer
 *
 * Returns:	---
 *
 * Use:		Encodes a block in a binary format.
 */

static void blob(block *b, dstr *d)
{
  DPUTC(d, b->tag);
  switch (b->tag) {
    case T_IDENT:
    case T_SIGALG:
    case T_HASHALG:
    case T_COMMENT:
      DPUTD(d, &b->d);
      DPUTC(d, 0);
      break;
    case T_DATE:
    case T_EXPIRE:
      DENSURE(d, 8);
      STORE32(d->buf + d->len, ((b->t & ~MASK32) >> 16) >> 16);
      STORE32(d->buf + d->len + 4, b->t);
      d->len += 8;
      break;
    case T_KEYID:
      DENSURE(d, 4);
      STORE32(d->buf + d->len, b->k);
      d->len += 4;
      break;
    case T_FILE:
    case T_SIGNATURE:
      DENSURE(d, 2);
      STORE16(d->buf + d->len, b->b.len);
      d->len += 2;
      DPUTD(d, &b->b);
      if (b->tag == T_FILE) {
	DPUTD(d, &b->d);
	DPUTC(d, 0);
      }
      break;
  }
}

/* --- @bwrite@ --- *
 *
 * Arguments:	@block *b@ = pointer to block to write
 *		@FILE *fp@ = stream to write on
 *
 * Returns:	---
 *
 * Use:		Writes a block on a stream in a textual format.
 */

static void bwrite(block *b, FILE *fp)
{
  fputs(tagtab[b->tag], fp);
  putc(' ', fp);
  switch (b->tag) {
    case T_IDENT:
    case T_SIGALG:
    case T_HASHALG:
    case T_COMMENT:
      putstring(fp, b->d.buf, 0);
      break;
    case T_DATE:
    case T_EXPIRE: {
      dstr d = DSTR_INIT;
      timestring(b->t, &d);
      putstring(fp, d.buf, 0);
      dstr_destroy(&d);
    } break;
    case T_KEYID:
      fprintf(fp, "%08lx", (unsigned long)b->k);
      break;
    case T_FILE:
    case T_SIGNATURE: {
      dstr d = DSTR_INIT;
      base64_ctx b64;
      base64_init(&b64);
      b64.maxline = 0;
      base64_encode(&b64, b->b.buf, b->b.len, &d);
      base64_encode(&b64, 0, 0, &d);
      dstr_write(&d, fp);
      if (b->tag == T_FILE) {
	putc(' ', fp);
	putstring(fp, b->d.buf, 0);
      }
    } break;
  }
  putc('\n', fp);
}

/* --- @bemit@ --- *
 *
 * Arguments:	@block *b@ = pointer to block to write
 *		@FILE *fp@ = file to write on
 *		@ghash *h@ = pointer to hash function
 *		@unsigned bin@ = binary/text flag
 *
 * Returns:	---
 *
 * Use:		Spits out a block properly.
 */

static void bemit(block *b, FILE *fp, ghash *h, unsigned bin)
{
  if (h || (fp && bin)) {
    dstr d = DSTR_INIT;
    blob(b, &d);
    if (h)
      h->ops->hash(h, d.buf, d.len);
    if (fp && bin)
      fwrite(d.buf, d.len, 1, fp);
  }
  if (fp && !bin)
    bwrite(b, fp);
}
    
/*----- Static variables --------------------------------------------------*/

static const char *keyring = "keyring";

/*----- Other shared functions --------------------------------------------*/

/* --- @keyreport@ --- *
 *
 * Arguments:	@const char *file@ = filename containing the error
 *		@int line@ = line number in file
 *		@const char *err@ = error text message
 *		@void *p@ = unimportant pointer
 *
 * Returns:	---
 *
 * Use:		Reports errors during the opening of a key file.
 */

static void keyreport(const char *file, int line, const char *err, void *p)
{
  moan("error in keyring `%s' at line `%s': %s", file, line, err);
}

/* --- @fhash@ --- *
 *
 * Arguments:	@const gchash *c@ = pointer to hash class
 *		@const char *file@ = file to hash
 *		@void *b@ = pointer to output buffer
 *
 * Returns:	Zero if it worked, or nonzero for a system error.
 *
 * Use:		Hashes a file.
 */

static int fhash(const gchash *c, const char *file, void *b)
{
  FILE *fp = fopen(file, "rb");
  ghash *h = c->init();
  char buf[4096];
  size_t sz;
  int rc = 0;

  if (!fp)
    return (-1);
  while ((sz = fread(buf, 1, sizeof(buf), fp)) > 0)
    h->ops->hash(h, buf, sz);
  if (ferror(fp))
    rc = -1;
  h->ops->done(h, b);
  h->ops->destroy(h);
  fclose(fp);
  return (rc);
}

/* --- @fhex@ --- *
 *
 * Arguments:	@FILE *fp@ = file to write on
 *		@const void *p@ = pointer to data to be written
 *		@size_t sz@ = size of the data to write
 *
 * Returns:	---
 *
 * Use:		Emits a hex dump to a stream.
 */

static void fhex(FILE *fp, const void *p, size_t sz)
{
  const octet *q = p;
  if (!sz)
    return;
  for (;;) {
    fprintf(fp, "%02x", *q++);
    sz--;
    if (!sz)
      break;
/*     putc(' ', fp); */
  }
}    

/*----- Signature generation ----------------------------------------------*/

static int sign(int argc, char *argv[])
{
#define f_raw 1u
#define f_bin 2u
#define f_bogus 4u

  unsigned f = 0;
  const char *kt = 0;
  const char *ki = 0;
  key_file kf;
  key *k;
  const sig *s = sigtab;
  const gchash *gch = &rmd160;
  ghash *h;
  time_t exp = KEXP_EXPIRE;
  unsigned verb = 0;
  const char *ifile = 0;
  const char *ofile = 0;
  const char *c = 0;
  FILE *ifp, *ofp;
  dstr d = DSTR_INIT;
  block b;
  int e;

  for (;;) {
    static struct option opts[] = {
      { "null",		0,		0,	'0' },
      { "binary",	0,		0,	'b' },
      { "verbose",	0,		0,	'v' },
      { "quiet",	0,		0,	'q' },
      { "algorithm",	OPTF_ARGREQ,	0,	'a' },
      { "hash",		OPTF_ARGREQ,	0,	'h' },
      { "comment",	OPTF_ARGREQ,	0,	'c' },
      { "file",		OPTF_ARGREQ,	0,	'f' },
      { "output",	OPTF_ARGREQ,	0,	'o' },
      { "keytype",	OPTF_ARGREQ,	0,	't' },
      { "keyid",	OPTF_ARGREQ,	0,	'i' },
      { "key",		OPTF_ARGREQ,	0,	'i' },
      { "expire",	OPTF_ARGREQ,	0,	'e' },
      { 0,		0,		0,	0 }
    };
    int i = mdwopt(argc, argv, "+0vqb a:h:c: f:o: t:i:k:e:", opts, 0, 0, 0);
    if (i < 0)
      break;
    switch (i) {
      case '0':
	f |= f_raw;
	break;
      case 'b':
	f |= f_bin;
	break;
      case 'v':
	verb++;
	break;
      case 'q':
	if (verb > 0)
	  verb--;
	break;
      case 'a':
	if ((s = getsig(optarg)) == 0) {
	  die(EXIT_FAILURE, "unknown or ambiguous signature algorithm `%s'",
	      optarg);
	}
	break;
      case 'h':
	if ((gch = gethash(optarg)) == 0) {
	  die(EXIT_FAILURE, "unknown or ambiguous hash function `%s'",
	      optarg);
	}
	break;
      case 'c':
	c = optarg;
	break;
      case 'f':
	ifile = optarg;
	break;
      case 'o':
	ofile = optarg;
	break;
      case 't':
	kt = optarg;
	break;
      case 'i':
      case 'k':
	ki = optarg;
	break;
      case 'e':
	if (strcmp(optarg, "forever") == 0)
	  exp = KEXP_FOREVER;
	else if ((exp = get_date(optarg, 0)) == -1)
	  die(EXIT_FAILURE, "bad expiry time");
	break;
      default:
	f |= f_bogus;
	break;
    }
  }
  if (optind != argc || (f & f_bogus))
    die(EXIT_FAILURE, "Usage: sign [-options]");

  /* --- Locate the signing key --- */

  if (key_open(&kf, keyring, KOPEN_WRITE, keyreport, 0))
    die(EXIT_FAILURE, "couldn't open keyring `%s'", keyring);
  if (ki) {
    if ((k = key_bytag(&kf, ki)) == 0)
      die(EXIT_FAILURE, "couldn't find key `%s'", ki);
  } else {
    if (!kt)
      kt = s->type;
    if ((k = key_bytype(&kf, kt)) == 0)
      die(EXIT_FAILURE, "no appropriate key of type `%s'", kt);
  }
  key_fulltag(k, &d);
  if (exp == KEXP_FOREVER && k->exp != KEXP_FOREVER) {
    die(EXIT_FAILURE, "key `%s' expires: can't create nonexpiring signature",
	d.buf);
  }

  /* --- Open files --- */

  if (!ifile)
    ifp = stdin;
  else if ((ifp = fopen(ifile, (f & f_raw) ? "rb" : "r")) == 0) {
    die(EXIT_FAILURE, "couldn't open input file `%s': %s",
	ifile, strerror(errno));
  }

  if (!ofile)
    ofp = stdout;
  else if ((ofp = fopen(ofile, (f & f_bin) ? "wb" : "w")) == 0) {
    die(EXIT_FAILURE, "couldn't open output file `%s': %s",
	ofile, strerror(errno));
  }

  h = gch->init();

  /* --- Emit the start of the output --- */

  binit(&b); b.tag = T_IDENT;
  dstr_putf(&b.d, "%s, Catacomb version " VERSION, QUIS);
  bemit(&b, ofp, 0, f & f_bin);
  
  breset(&b); b.tag = T_SIGALG; DPUTS(&b.d, s->name);
  bemit(&b, ofp, h, f & f_bin);

  breset(&b); b.tag = T_HASHALG; DPUTS(&b.d, gch->name);
  bemit(&b, ofp, h, f & f_bin);

  breset(&b); b.tag = T_KEYID; b.k = k->id;
  bemit(&b, ofp, h, f & f_bin);

  /* --- Start hashing, and emit the datestamps and things --- */

  {
    time_t now = time(0);

    breset(&b); b.tag = T_DATE; b.t = now; bemit(&b, ofp, h, f & f_bin);
    if (exp == KEXP_EXPIRE)
      exp = now + 86400 * 28;
    breset(&b); b.tag = T_EXPIRE; b.t = exp; bemit(&b, ofp, h, f & f_bin);
    if (c) {
      breset(&b); b.tag = T_COMMENT; DPUTS(&b.d, c);
      bemit(&b, ofp, h, f & f_bin);
    }

    if (!(f & f_bin))
      putc('\n', ofp);
  }

  /* --- Now hash the various files --- */

  for (;;) {

    /* --- Stop on an output error --- */

    if (ferror(ofp)) {
      f |= f_bogus;
      break;
    }

    /* --- Read the next filename to hash --- */

    breset(&b);
    if (getstring(ifp, &b.d, f & f_raw))
      break;
    b.tag = T_FILE;
    DENSURE(&b.b, h->ops->c->hashsz);
    if (fhash(gch, b.d.buf, b.b.buf)) {
      moan("Error reading `%s': %s", b.d.buf, strerror(errno));
      f |= f_bogus;
    } else {
      b.b.len += h->ops->c->hashsz;
      if (verb) {
	fhex(stderr, b.b.buf, b.b.len);
	fprintf(stderr, " %s\n", b.d.buf);
      }
      bemit(&b, ofp, h, f & f_bin);
    }
  }

  /* --- Create the signature --- */

  if (!(f & f_bogus)) {
    breset(&b);
    b.tag = T_SIGNATURE;
    DENSURE(&b.d, h->ops->c->hashsz);
    h->ops->done(h, b.d.buf);
    if ((e = s->sign(k, b.d.buf, h->ops->c->hashsz, &b.b)) != 0) {
      moan("error creating signature: %s", key_strerror(e));
      f |= f_bogus;
    }
    if (!(f & f_bogus)) {
      bemit(&b, ofp, 0, f & f_bin);
      key_used(&kf, k, exp);
    }
  }

  /* --- Tidy up at the end --- */

  bdestroy(&b);
  if (ifile)
    fclose(ifp);
  if (ofile) {
    if (fclose(ofp))
      f |= f_bogus;
  } else {
    if (fflush(ofp))
      f |= f_bogus;
  }
  if ((e = key_close(&kf)) != 0) {
    switch (e) {
      case KWRITE_FAIL:
	die(EXIT_FAILURE, "couldn't write file `%s': %s",
	    keyring, strerror(errno));
      case KWRITE_BROKEN:
	die(EXIT_FAILURE, "keyring file `%s' broken: %s (repair manually)",
	    keyring, strerror(errno));
    }
  }
  if (f & f_bogus)
    die(EXIT_FAILURE, "error(s) occurred while creating signature");
  return (EXIT_SUCCESS);

#undef f_raw
#undef f_bin
#undef f_bogus
}

/*----- Signature verification --------------------------------------------*/

static int verify(int argc, char *argv[])
{
#define f_bogus 1u
#define f_bin 2u
#define f_ok 4u

  unsigned f = 0;
  unsigned verb = 1;
  key_file kf;
  key *k = 0;
  sig *s = sigtab;
  const gchash *gch = &rmd160;
  dstr d = DSTR_INIT;
  ghash *h = 0;
  FILE *fp;
  block b;
  int e;

  /* --- Parse the options --- */

  for (;;) {
    static struct option opts[] = {
      { "verbose",	0,		0,	'v' },
      { "quiet",	0,		0,	'q' },
      { 0,		0,		0,	0 }
    };
    int i = mdwopt(argc, argv, "+vq", opts, 0, 0, 0);
    if (i < 0)
      break;
    switch (i) {
      case 'v':
	verb++;
	break;
      case 'q':
	if (verb)
	  verb--;
	break;
      default:
	f |= f_bogus;
	break;
    }
  }
  argc -= optind;
  argv += optind;
  if ((f & f_bogus) || argc > 1)
    die(EXIT_FAILURE, "Usage: verify [-qv] [file]");

  /* --- Open the key file, and start reading the input file --- */

  if (key_open(&kf, keyring, KOPEN_READ, keyreport, 0))
    die(EXIT_FAILURE, "couldn't open keyring `%s'\n", keyring);
  if (argc < 1)
    fp = stdin;
  else {
    if ((fp = fopen(argv[0], "rb")) == 0) {
      die(EXIT_FAILURE, "couldn't open file `%s': %s\n",
	      argv[0], strerror(errno));
    }
    if (getc(fp) == 0) {
      ungetc(0, fp);
      f |= f_bin;
    } else {
      fclose(fp);
      if ((fp = fopen(argv[0], "r")) == 0) {
	die(EXIT_FAILURE, "couldn't open file `%s': %s\n",
		argv[0], strerror(errno));
      }
    }
  }

  /* --- Read the introductory matter --- */

  binit(&b);
  for (;;) {    
    breset(&b);
    e = bget(&b, fp, f & f_bin);
    if (e < 0)
      die(EXIT_FAILURE, "error reading packet: %s\n", errtab[-e]);
    if (e >= T_BEGIN)
      break;
    switch (e) {
      case T_IDENT:
	if (verb > 2)
	  printf("INFO ident: `%s'\n", b.d.buf);
	break;
      case T_SIGALG:
	if ((s = getsig(b.d.buf)) == 0) {
	  if (verb)
	    printf("FAIL unknown signature algorithm `%s'\n", b.d.buf);
	  exit(EXIT_FAILURE);
	}
	if (verb > 2)
	  printf("INFO signature algorithm: %s\n", s->name);
	break;
      case T_HASHALG:
	if ((gch = gethash(b.d.buf)) == 0) {
	  if (verb)
	    printf("FAIL unknown hash function `%s'\n", b.d.buf);
	  exit(EXIT_FAILURE);
	}
	if (verb > 2)
	  printf("INFO hash function algorithm: %s\n", gch->name);
	break;
      case T_KEYID:
	if ((k = key_byid(&kf, b.k)) == 0) {
	  if (verb)
	    printf("FAIL key %08lx not found\n", (unsigned long)b.k);
	  exit(EXIT_FAILURE);
	}
	if (verb > 2) {
	  DRESET(&b.d);
	  key_fulltag(k, &b.d);
	  printf("INFO key: %s\n", b.d.buf);
	}
	break;
      default:
	die(EXIT_FAILURE, "(internal) unknown packet type\n");
	break;
    }
  }

  /* --- Initialize the hash function and start reading hashed packets --- */

  h = gch->init();

  if (!k) {
    if (verb)
      puts("FAIL no keyid packet found");
    exit(EXIT_FAILURE);
  }

  {
    block bb;
    binit(&bb);
    breset(&bb); bb.tag = T_SIGALG; DPUTS(&bb.d, s->name);
    bemit(&bb, 0, h, 0);
    breset(&bb); bb.tag = T_HASHALG; DPUTS(&bb.d, gch->name);
    bemit(&bb, 0, h, 0);
    breset(&bb); bb.tag = T_KEYID; bb.k = k->id;
    bemit(&bb, 0, h, 0);
    bdestroy(&bb);
  }

  for (;;) {
    switch (e) {
      case T_COMMENT:
	if (verb > 1)
	  printf("INFO comment: `%s'\n", b.d.buf);
	bemit(&b, 0, h, 0);
	break;
      case T_DATE:
	if (verb > 2) {
	  DRESET(&b.d);
	  timestring(b.t, &b.d);
	  printf("INFO date: %s\n", b.d.buf);
	}
	bemit(&b, 0, h, 0);
	break;
      case T_EXPIRE: {
	time_t now = time(0);
	if (b.t < now) {
	  if (verb > 1)
	    puts("BAD signature has expired");
	  f |= f_bogus;
	}
	if (verb > 2) {
	  DRESET(&b.d);
	  timestring(b.t, &b.d);
	  printf("INFO expires: %s\n", b.d.buf);
	}
	bemit(&b, 0, h, 0);
      }	break;
      case T_FILE:
	DRESET(&d);
	DENSURE(&d, gch->hashsz);
	if (fhash(gch, b.d.buf, d.buf)) {
	  if (verb > 1) {
	    printf("BAD error reading file `%s': %s\n",
		    b.d.buf, strerror(errno));
	  }
	  f |= f_bogus;
	} else if (b.b.len != gch->hashsz ||
		   memcmp(d.buf, b.b.buf, b.b.len) != 0) {
	  if (verb > 1)
	    printf("BAD file `%s' has incorrect hash\n", b.d.buf);
	  f |= f_bogus;
	} else if (verb > 3) {
	  fputs("INFO hash: ", stdout);
	  fhex(stdout, b.b.buf, b.b.len);
	  printf(" %s\n", b.d.buf);
	}
	bemit(&b, 0, h, 0);
	break;
      case T_SIGNATURE:
	DRESET(&b.d);
	DENSURE(&b.d, h->ops->c->hashsz);
	b.d.len += h->ops->c->hashsz;
	h->ops->done(h, b.d.buf);
	e = s->verify(k, b.d.buf, b.d.len, b.b.buf, b.b.len);
	if (e != 1) {
	  if (verb > 1) {
	    if (e < 0) {
	      printf("BAD error unpacking key: %s\n", key_strerror(e));
	    } else
	      puts("BAD bad signature");
	  }
	  f |= f_bogus;
	} else if (verb > 2)
	  puts("INFO good signature");
	goto done;
      default:
	if (verb)
	  printf("FAIL invalid packet type %i\n", e);
	exit(EXIT_FAILURE);
	break;
    }
    breset(&b);
    e = bget(&b, fp, f & f_bin);
    if (e < 0) {
      if (verb)
	printf("FAIL error reading packet: %s\n", errtab[-e]);
      exit(EXIT_FAILURE);
    }
  }
done:
  bdestroy(&b);
  dstr_destroy(&d);
  key_close(&kf);
  if (fp != stdin)
    fclose(fp);
  if (verb) {
    if (f & f_bogus)
      puts("FAIL signature invalid");
    else
      puts("OK signature verified");
  }
  return (f & f_bogus ? EXIT_FAILURE : EXIT_SUCCESS);

#undef f_bogus
#undef f_bin
#undef f_ok
}

/*----- Main code ---------------------------------------------------------*/

typedef struct cmd {
  const char *name;
  int (*func)(int /*argc*/, char */*argv*/[]);
  const char *usage;
  const char *help;
} cmd;

static cmd cmdtab[] = {
/*   { "manifest", manifest, */
/*     "manifest [-0] [-o output]" }, */
  { "sign", sign,
    "sign [-options]\n\
	[-0bqv] [-a alg] [-h hash] [-t keytype] [-i keyid]\n\
	[-e expire] [-f file] [-o output]", "\
Options:\n\
\n\
-0, --null		Read null-terminated filenames from stdin.\n\
-b, --binary		Produce a binary output file.\n\
-q, --quiet		Produce fewer messages while working.\n\
-v, --verbose		Produce more messages while working.\n\
-a, --algorithm=SIGALG	Use the SIGALG signature algorithm.\n\
-h, --hash=HASHASL	Use the HASHALG message digest algorithm.\n\
-c, --comment=COMMENT	Include COMMENT in the output file.\n\
-f, --file=FILE		Read filenames to hash from FILE.\n\
-o, --output=FILE	Write the signed result to FILE.\n\
-t, --keytype=TYPE	Use a key with type TYPE to do the signing.\n\
-i, --keyid=ID		Use the key with the given ID to do the signing.\n\
-e, --expire=TIME	The signature should expire after TIME.\n\
" },
  { "verify", verify,
    "verify [-qv] [file]", "\
Options:\n\
\n\
-q, --quiet		Produce fewer messages while working.\n\
-v, --verbose		Produce more messages while working.\n\
" },
  { 0, 0, 0 }
};

/* --- @findcmd@ --- *
 *
 * Arguments:	@const char *name@ = a command name
 *
 * Returns:	Pointer to the command structure.
 *
 * Use:		Looks up a command by name.  If the command isn't found, an
 *		error is reported and the program is terminated.
 */

static cmd *findcmd(const char *name)
{
  cmd *c, *chosen = 0;
  size_t sz = strlen(name);

  for (c = cmdtab; c->name; c++) {
    if (strncmp(name, c->name, sz) == 0) {
      if (c->name[sz] == 0) {
	chosen = c;
	break;
      } else if (chosen)
	die(EXIT_FAILURE, "ambiguous command name `%s'", name);
      else
	chosen = c;
    }
  }
  if (!chosen)
    die(EXIT_FAILURE, "unknown command name `%s'", name);
  return (chosen);
}

static void version(FILE *fp)
{
  pquis(fp, "$, Catacomb version " VERSION "\n");
}

static void usage(FILE *fp)
{
  pquis(fp, "Usage: $ [-k keyring] command [args]\n");
}

static void help(FILE *fp, char **argv)
{
  cmd *c;

  if (*argv) {
    c = findcmd(*argv);
    fprintf(fp, "Usage: %s [-k keyring] %s\n", QUIS, c->usage);
    if (c->help) {
      fputc('\n', fp);	
      fputs(c->help, fp);
    }
  } else {
    version(fp);
    fputc('\n', fp);
    usage(fp);
    fputs("\n\
Create and verify signatures on lists of files.\n\
\n", fp);
    for (c = cmdtab; c->name; c++)
      fprintf(fp, "%s\n", c->usage);
  }
}

/* --- @main@ --- *
 *
 * Arguments:	@int argc@ = number of command line arguments
 *		@char *argv[]@ = vector of command line arguments
 *
 * Returns:	Zero if successful, nonzero otherwise.
 *
 * Use:		Signs or verifies signatures on lists of files.  Useful for
 *		ensuring that a distribution is unmolested.
 */

int main(int argc, char *argv[])
{
  unsigned f = 0;

#define f_bogus 1u

  /* --- Initialize the library --- */

  ego(argv[0]);
  sub_init();
  rand_noisesrc(RAND_GLOBAL, &noise_source);
  rand_seed(RAND_GLOBAL, 160);

  /* --- Parse options --- */

  for (;;) {
    static struct option opts[] = {
      { "help",		0,		0,	'h' },
      { "version",	0,		0,	'v' },
      { "usage",	0,		0,	'u' },
      { "keyring",	OPTF_ARGREQ,	0,	'k' },
      { 0,		0,		0,	0 }
    };
    int i = mdwopt(argc, argv, "+hvu k:", opts, 0, 0, 0);
    if (i < 0)
      break;
    switch (i) {
      case 'h':
	help(stdout, argv + optind);
	exit(0);
	break;
      case 'v':
	version(stdout);
	exit(0);
	break;
      case 'u':
	usage(stdout);
	exit(0);
      case 'k':
	keyring = optarg;
	break;
      default:
	f |= f_bogus;
	break;
    }
  }

  argc -= optind;
  argv += optind;
  optind = 0;
  if (f & f_bogus || argc < 1) {
    usage(stderr);
    exit(EXIT_FAILURE);
  }

  /* --- Dispatch to the correct subcommand handler --- */

  return (findcmd(argv[0])->func(argc, argv));

#undef f_bogus
}

/*----- That's all, folks -------------------------------------------------*/