gpgme/src/sign.c

/* sign.c - Signing function.
   Copyright (C) 2000 Werner Koch (dd9jn)
   Copyright (C) 2001, 2002, 2003, 2004, 2007 g10 Code GmbH

   This file is part of GPGME.
 
   GPGME is free software; you can redistribute it and/or modify it
   under the terms of the GNU Lesser General Public License as
   published by the Free Software Foundation; either version 2.1 of
   the License, or (at your option) any later version.
   
   GPGME 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
   Lesser General Public License for more details.
   
   You should have received a copy of the GNU Lesser General Public
   License along with this program; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
   02111-1307, USA.  */

#if HAVE_CONFIG_H
#include <config.h>
#endif
#include <stdlib.h>
#include <string.h>
#include <errno.h>

/* Suppress warning for accessing deprecated member "class".  */
#define _GPGME_IN_GPGME 1
#include "gpgme.h"
#include "context.h"
#include "ops.h"
#include "util.h"
#include "debug.h"


typedef struct
{
  struct _gpgme_op_sign_result result;

  /* A pointer to the next pointer of the last invalid signer in
     the list.  This makes appending new invalid signers painless
     while preserving the order.  */
  gpgme_invalid_key_t *last_signer_p;

  /* Likewise for signature information.  */
  gpgme_new_signature_t *last_sig_p;

  /* Flags used while processing the status lines.  */
  unsigned int ignore_inv_recp:1;
  unsigned int inv_sgnr_seen:1;
  unsigned int sig_created_seen:1;
} *op_data_t;


static void
release_op_data (void *hook)
{
  op_data_t opd = (op_data_t) hook;
  gpgme_invalid_key_t invalid_signer = opd->result.invalid_signers;
  gpgme_new_signature_t sig = opd->result.signatures;

  while (invalid_signer)
    {
      gpgme_invalid_key_t next = invalid_signer->next;
      if (invalid_signer->fpr)
	free (invalid_signer->fpr);
      free (invalid_signer);
      invalid_signer = next;
    }

  while (sig)
    {
      gpgme_new_signature_t next = sig->next;
      free (sig->fpr);
      free (sig);
      sig = next;
    }
}


gpgme_sign_result_t
gpgme_op_sign_result (gpgme_ctx_t ctx)
{
  void *hook;
  op_data_t opd;
  gpgme_error_t err;

  TRACE_BEG (DEBUG_CTX, "gpgme_op_sign_result", ctx);

  err = _gpgme_op_data_lookup (ctx, OPDATA_SIGN, &hook, -1, NULL);
  opd = hook;
  if (err || !opd)
    {
      TRACE_SUC0 ("result=(null)");
      return NULL;
    }

  if (_gpgme_debug_trace ())
    {
      gpgme_invalid_key_t inv_key = opd->result.invalid_signers;
      gpgme_new_signature_t sig = opd->result.signatures;
      int inv_signers = 0;
      int signatures = 0;

      while (inv_key)
	{
	  inv_signers++;
	  inv_key = inv_key->next;
	}
      while (sig)
	{
	  signatures++;
	  sig = sig->next;
	}

      TRACE_LOG2 ("result: invalid signers: %i, signatures: %i",
		  inv_signers, signatures);
      inv_key = opd->result.invalid_signers;
      while (inv_key)
	{
	  TRACE_LOG3 ("result: invalid signer: fpr=%s, reason=%s <%s>",
		      inv_key->fpr, gpgme_strerror (inv_key->reason),
		      gpgme_strsource (inv_key->reason));
	  inv_key = inv_key->next;
	}
      sig = opd->result.signatures;
      while (sig)
	{
	  TRACE_LOG6 ("result: signature: type=%i, pubkey_algo=%i, "
		      "hash_algo=%i, timestamp=%li, fpr=%s, sig_class=%i",
		      sig->type, sig->pubkey_algo, sig->hash_algo,
		      sig->timestamp, sig->fpr, sig->sig_class);
	  sig = sig->next;
	}
    }

  TRACE_SUC1 ("result=%p", &opd->result);
  return &opd->result;
}


static gpgme_error_t
parse_sig_created (char *args, gpgme_new_signature_t *sigp)
{
  gpgme_new_signature_t sig;
  char *tail;

  sig = malloc (sizeof (*sig));
  if (!sig)
    return gpg_error_from_syserror ();

  sig->next = NULL;
  switch (*args)
    {
    case 'S':
      sig->type = GPGME_SIG_MODE_NORMAL;
      break;

    case 'D':
      sig->type = GPGME_SIG_MODE_DETACH;
      break;

    case 'C':
      sig->type = GPGME_SIG_MODE_CLEAR;
      break;

    default:
      /* The backend engine is not behaving.  */
      free (sig);
      return gpg_error (GPG_ERR_INV_ENGINE);
    }

  args++;
  if (*args != ' ')
    {
      free (sig);
      return gpg_error (GPG_ERR_INV_ENGINE);
    }

  gpg_err_set_errno (0);
  sig->pubkey_algo = strtol (args, &tail, 0);
  if (errno || args == tail || *tail != ' ')
    {
      /* The crypto backend does not behave.  */
      free (sig);
      return gpg_error (GPG_ERR_INV_ENGINE);
    }
  args = tail;

  sig->hash_algo = strtol (args, &tail, 0);
  if (errno || args == tail || *tail != ' ')
    {
      /* The crypto backend does not behave.  */
      free (sig);
      return gpg_error (GPG_ERR_INV_ENGINE);
    }
  args = tail;

  sig->sig_class = strtol (args, &tail, 0);
  sig->class = sig->sig_class;
  sig->_obsolete_class = sig->sig_class;
  if (errno || args == tail || *tail != ' ')
    {
      /* The crypto backend does not behave.  */
      free (sig);
      return gpg_error (GPG_ERR_INV_ENGINE);
    }
  args = tail;

  sig->timestamp = _gpgme_parse_timestamp (args, &tail);
  if (sig->timestamp == -1 || args == tail || *tail != ' ')
    {
      /* The crypto backend does not behave.  */
      free (sig);
      return gpg_error (GPG_ERR_INV_ENGINE);
    }
  args = tail;
  while (*args == ' ')
    args++;

  if (!*args)
    {
      /* The crypto backend does not behave.  */
      free (sig);
      return gpg_error (GPG_ERR_INV_ENGINE);
    }

  tail = strchr (args, ' ');
  if (tail)
    *tail = '\0';

  sig->fpr = strdup (args);
  if (!sig->fpr)
    {
      int saved_errno = errno;
      free (sig);
      return gpg_error_from_errno (saved_errno);
    }
  *sigp = sig;
  return 0;
}


gpgme_error_t
_gpgme_sign_status_handler (void *priv, gpgme_status_code_t code, char *args)
{
  gpgme_ctx_t ctx = (gpgme_ctx_t) priv;
  gpgme_error_t err;
  void *hook;
  op_data_t opd;

  err = _gpgme_passphrase_status_handler (priv, code, args);
  if (err)
    return err;

  err = _gpgme_op_data_lookup (ctx, OPDATA_SIGN, &hook, -1, NULL);
  opd = hook;
  if (err)
    return err;

  switch (code)
    {
    case GPGME_STATUS_SIG_CREATED:
      opd->sig_created_seen = 1;
      err = parse_sig_created (args, opd->last_sig_p);
      if (err)
	return err;

      opd->last_sig_p = &(*opd->last_sig_p)->next;
      break;

    case GPGME_STATUS_INV_RECP:
      if (opd->inv_sgnr_seen && opd->ignore_inv_recp)
        break; 
      /* FALLTROUGH */
    case GPGME_STATUS_INV_SGNR:
      if (code == GPGME_STATUS_INV_SGNR)
        opd->inv_sgnr_seen = 1;
      err = _gpgme_parse_inv_recp (args, opd->last_signer_p);
      if (err)
	return err;

      opd->last_signer_p = &(*opd->last_signer_p)->next;
      break;

    case GPGME_STATUS_EOF:
      /* The UI server does not send information about the created
         signature.  This is irrelevant for this protocol and thus we
         should not check for that.  */
      if (opd->result.invalid_signers)
	err = gpg_error (GPG_ERR_UNUSABLE_SECKEY);
      else if (!opd->sig_created_seen
               && ctx->protocol != GPGME_PROTOCOL_UISERVER)
	err = gpg_error (GPG_ERR_GENERAL);
      break;

    default:
      break;
    }
  return err;
}


static gpgme_error_t
sign_status_handler (void *priv, gpgme_status_code_t code, char *args)
{
  gpgme_error_t err;

  err = _gpgme_progress_status_handler (priv, code, args);
  if (!err)
    err = _gpgme_sign_status_handler (priv, code, args);
  return err;
}


static gpgme_error_t
sign_init_result (gpgme_ctx_t ctx, int ignore_inv_recp)
{
  gpgme_error_t err;
  void *hook;
  op_data_t opd;

  err = _gpgme_op_data_lookup (ctx, OPDATA_SIGN, &hook,
			       sizeof (*opd), release_op_data);
  opd = hook;
  if (err)
    return err;
  opd->last_signer_p = &opd->result.invalid_signers;
  opd->last_sig_p = &opd->result.signatures;
  opd->ignore_inv_recp = !!ignore_inv_recp;
  opd->inv_sgnr_seen = 0;
  opd->sig_created_seen = 0;
  return 0;
}

gpgme_error_t
_gpgme_op_sign_init_result (gpgme_ctx_t ctx)
{
  return sign_init_result (ctx, 0);
}


static gpgme_error_t
sign_start (gpgme_ctx_t ctx, int synchronous, gpgme_data_t plain,
	    gpgme_data_t sig, gpgme_sig_mode_t mode)
{
  gpgme_error_t err;

  err = _gpgme_op_reset (ctx, synchronous);
  if (err)
    return err;

  /* If we are using the CMS protocol, we ignore the INV_RECP status
     code if a newer GPGSM is in use.  GPGMS does not support combined
     sign+encrypt and thus this can't harm.  */
  err = sign_init_result (ctx, (ctx->protocol == GPGME_PROTOCOL_CMS));
  if (err)
    return err;

  if (mode != GPGME_SIG_MODE_NORMAL && mode != GPGME_SIG_MODE_DETACH
      && mode != GPGME_SIG_MODE_CLEAR)
    return gpg_error (GPG_ERR_INV_VALUE);

  if (!plain)
    return gpg_error (GPG_ERR_NO_DATA);
  if (!sig)
    return gpg_error (GPG_ERR_INV_VALUE);

  if (ctx->passphrase_cb)
    {
      err = _gpgme_engine_set_command_handler
	(ctx->engine, _gpgme_passphrase_command_handler, ctx, NULL);
      if (err)
	return err;
    }

  _gpgme_engine_set_status_handler (ctx->engine, sign_status_handler,
				    ctx);

  return _gpgme_engine_op_sign (ctx->engine, plain, sig, mode, ctx->use_armor,
				ctx->use_textmode, ctx->include_certs,
				ctx /* FIXME */);
}


/* Sign the plaintext PLAIN and store the signature in SIG.  */
gpgme_error_t
gpgme_op_sign_start (gpgme_ctx_t ctx, gpgme_data_t plain, gpgme_data_t sig,
		     gpgme_sig_mode_t mode)
{
  gpg_error_t err;
  TRACE_BEG3 (DEBUG_CTX, "gpgme_op_sign_start", ctx,
	      "plain=%p, sig=%p, mode=%i", plain, sig, mode);
  err = sign_start (ctx, 0, plain, sig, mode);
  return TRACE_ERR (err);
}


/* Sign the plaintext PLAIN and store the signature in SIG.  */
gpgme_error_t
gpgme_op_sign (gpgme_ctx_t ctx, gpgme_data_t plain, gpgme_data_t sig,
	       gpgme_sig_mode_t mode)
{
  gpgme_error_t err;

  TRACE_BEG3 (DEBUG_CTX, "gpgme_op_sign", ctx,
	      "plain=%p, sig=%p, mode=%i", plain, sig, mode);
  err = sign_start (ctx, 1, plain, sig, mode);
  if (!err)
    err = _gpgme_wait_one (ctx);
  return TRACE_ERR (err);
}