/* findkey.c - locate the secret key * Copyright (C) 2001 Free Software Foundation, Inc. * * This file is part of GnuPG. * * GnuPG is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * GnuPG 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 General Public License for more details. * * You should have received a copy of the GNU 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 */ #include #include #include #include #include #include #include #include #include #include "agent.h" static int unprotect (GCRY_SEXP s_skey) { struct pin_entry_info_s *pi; int rc; /* fixme: check whether the key needs unprotection */ /* fixme: allocate the pin in secure memory */ pi = xtrycalloc (1, sizeof (*pi) + 100); pi->max_length = 100; pi->min_digits = 4; pi->max_digits = 8; pi->max_tries = 3; rc = agent_askpin (NULL, pi); /* fixme: actually unprotect the key and ask again until we get a valid PIN - agent_askpin takes care of counting failed tries */ xfree (pi); return rc; } /* Return the secret key as an S-Exp after locating it using the grip. Returns NULL if key is not available. */ GCRY_SEXP agent_key_from_file (const unsigned char *grip) { int i, rc; char *fname; FILE *fp; struct stat st; char *buf; size_t buflen, erroff; GCRY_SEXP s_skey; char hexgrip[41]; for (i=0; i < 20; i++) sprintf (hexgrip+2*i, "%02X", grip[i]); hexgrip[40] = 0; fname = make_filename (opt.homedir, "private-keys-v1.d", hexgrip, NULL ); fp = fopen (fname, "rb"); if (!fp) { log_error ("can't open `%s': %s\n", fname, strerror (errno)); xfree (fname); return NULL; } if (fstat (fileno(fp), &st)) { log_error ("can't stat `%s': %s\n", fname, strerror (errno)); xfree (fname); fclose (fp); return NULL; } buflen = st.st_size; buf = xmalloc (buflen+1); if (fread (buf, buflen, 1, fp) != 1) { log_error ("error reading `%s': %s\n", fname, strerror (errno)); xfree (fname); fclose (fp); xfree (buf); return NULL; } rc = gcry_sexp_sscan (&s_skey, &erroff, buf, buflen); xfree (fname); fclose (fp); xfree (buf); if (rc) { log_error ("failed to build S-Exp (off=%u): %s\n", (unsigned int)erroff, gcry_strerror (rc)); return NULL; } rc = unprotect (s_skey); if (rc) { gcry_sexp_release (s_skey); log_error ("failed to unprotect the secret key: %s\n", gcry_strerror (rc)); return NULL; } return s_skey; }