/* app-nks.c - The Telesec NKS 2.0 card application. * Copyright (C) 2004 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, * USA. */ #include #include #include #include #include #include #include #include "scdaemon.h" #include "i18n.h" #include "iso7816.h" #include "app-common.h" #include "tlv.h" static struct { int fid; /* File ID. */ int certtype; /* Type of certificate or 0 if it is not a certificate. */ int iskeypair; /* If true has the FID of the correspoding certificate. */ int issignkey; /* True if file is a key usable for signing. */ int isenckey; /* True if file is a key usable for decryption. */ } filelist[] = { { 0x4531, 0, 0xC000, 1, 0 }, { 0xC000, 101 }, { 0x4331, 100 }, { 0x4332, 100 }, { 0xB000, 110 }, { 0x45B1, 0, 0xC200, 0, 1 }, { 0xC200, 101 }, { 0x43B1, 100 }, { 0x43B2, 100 }, { 0, 0 } }; /* Read the file with FID, assume it contains a public key and return its keygrip in the caller provided 41 byte buffer R_GRIPSTR. */ static gpg_error_t keygripstr_from_pk_file (int slot, int fid, char *r_gripstr) { gpg_error_t err; unsigned char grip[20]; unsigned char *buffer[2]; size_t buflen[2]; gcry_sexp_t sexp; int i; err = iso7816_select_file (slot, fid, 0, NULL, NULL); if (err) return err; err = iso7816_read_record (slot, 1, 1, 0, &buffer[0], &buflen[0]); if (err) return err; err = iso7816_read_record (slot, 2, 1, 0, &buffer[1], &buflen[1]); if (err) { xfree (buffer[0]); return err; } for (i=0; i < 2; i++) { /* Check that the value appears like an integer encoded as Simple-TLV. We don't check the tag because the tests cards I have use 1 for both, the modulus and the exponent - the example in the documentation gives 2 for the exponent. */ if (buflen[i] < 3) err = gpg_error (GPG_ERR_TOO_SHORT); else if (buffer[i][1] != buflen[i]-2 ) err = gpg_error (GPG_ERR_INV_OBJ); } if (!err) err = gcry_sexp_build (&sexp, NULL, "(public-key (rsa (n %b) (e %b)))", (int)buflen[0]-2, buffer[0]+2, (int)buflen[1]-2, buffer[1]+2); xfree (buffer[0]); xfree (buffer[1]); if (err) return err; if (!gcry_pk_get_keygrip (sexp, grip)) { err = gpg_error (GPG_ERR_INTERNAL); /* i.e. RSA not supported by libgcrypt. */ } else { for (i=0; i < 20; i++) sprintf (r_gripstr+i*2, "%02X", grip[i]); } gcry_sexp_release (sexp); return err; } static gpg_error_t do_learn_status (APP app, CTRL ctrl) { gpg_error_t err; char ct_buf[100], id_buf[100]; int i; /* Output information about all useful objects. */ for (i=0; filelist[i].fid; i++) { if (filelist[i].certtype) { size_t len; len = app_help_read_length_of_cert (app->slot, filelist[i].fid, NULL); if (len) { /* FIXME: We should store the length in the application's context so that a following readcert does only need to read that many bytes. */ sprintf (ct_buf, "%d", filelist[i].certtype); sprintf (id_buf, "NKS-DF01.%04X", filelist[i].fid); send_status_info (ctrl, "CERTINFO", ct_buf, strlen (ct_buf), id_buf, strlen (id_buf), NULL, (size_t)0); } } else if (filelist[i].iskeypair) { char gripstr[40+1]; err = keygripstr_from_pk_file (app->slot, filelist[i].fid, gripstr); if (err) log_error ("can't get keygrip from FID 0x%04X: %s\n", filelist[i].fid, gpg_strerror (err)); else { sprintf (id_buf, "NKS-DF01.%04X", filelist[i].fid); send_status_info (ctrl, "KEYPAIRINFO", gripstr, 40, id_buf, strlen (id_buf), NULL, (size_t)0); } } } return 0; } /* Read the certificate with id CERTID (as returned by learn_status in the CERTINFO status lines) and return it in the freshly allocated buffer put into CERT and the length of the certificate put into CERTLEN. */ static gpg_error_t do_readcert (app_t app, const char *certid, unsigned char **cert, size_t *certlen) { int i, fid; gpg_error_t err; unsigned char *buffer; const unsigned char *p; size_t buflen, n; int class, tag, constructed, ndef; size_t totobjlen, objlen, hdrlen; int rootca = 0; *cert = NULL; *certlen = 0; if (strncmp (certid, "NKS-DF01.", 9) ) return gpg_error (GPG_ERR_INV_ID); certid += 9; if (!hexdigitp (certid) || !hexdigitp (certid+1) || !hexdigitp (certid+2) || !hexdigitp (certid+3) || certid[4]) return gpg_error (GPG_ERR_INV_ID); fid = xtoi_4 (certid); for (i=0; filelist[i].fid; i++) if ((filelist[i].certtype || filelist[i].iskeypair) && filelist[i].fid == fid) break; if (!filelist[i].fid) return gpg_error (GPG_ERR_NOT_FOUND); /* If the requested objects is a plain public key, redirect it to the corresponding certificate. The whole system is a bit messy becuase we sometime use the key directly or let the caller retrieve the key from the certificate. The valid point behind that is to support not-yet stored certificates. */ if (filelist[i].iskeypair) fid = filelist[i].iskeypair; /* Read the entire file. fixme: This could be optimized by first reading the header to figure out how long the certificate actually is. */ err = iso7816_select_file (app->slot, fid, 0, NULL, NULL); if (err) { log_error ("error selecting FID 0x%04X: %s\n", fid, gpg_strerror (err)); return err; } err = iso7816_read_binary (app->slot, 0, 0, &buffer, &buflen); if (err) { log_error ("error reading certificate from FID 0x%04X: %s\n", fid, gpg_strerror (err)); return err; } if (!buflen || *buffer == 0xff) { log_info ("no certificate contained in FID 0x%04X\n", fid); err = gpg_error (GPG_ERR_NOT_FOUND); goto leave; } /* Now figure something out about the object. */ p = buffer; n = buflen; err = parse_ber_header (&p, &n, &class, &tag, &constructed, &ndef, &objlen, &hdrlen); if (err) goto leave; if ( class == CLASS_UNIVERSAL && tag == TAG_SEQUENCE && constructed ) ; else if ( class == CLASS_UNIVERSAL && tag == TAG_SET && constructed ) rootca = 1; else return gpg_error (GPG_ERR_INV_OBJ); totobjlen = objlen + hdrlen; assert (totobjlen <= buflen); err = parse_ber_header (&p, &n, &class, &tag, &constructed, &ndef, &objlen, &hdrlen); if (err) goto leave; if (rootca) ; else if (class == CLASS_UNIVERSAL && tag == TAG_OBJECT_ID && !constructed) { const unsigned char *save_p; /* The certificate seems to be contained in a userCertificate container. Skip this and assume the following sequence is the certificate. */ if (n < objlen) { err = gpg_error (GPG_ERR_INV_OBJ); goto leave; } p += objlen; n -= objlen; save_p = p; err = parse_ber_header (&p, &n, &class, &tag, &constructed, &ndef, &objlen, &hdrlen); if (err) goto leave; if ( !(class == CLASS_UNIVERSAL && tag == TAG_SEQUENCE && constructed) ) return gpg_error (GPG_ERR_INV_OBJ); totobjlen = objlen + hdrlen; assert (save_p + totobjlen <= buffer + buflen); memmove (buffer, save_p, totobjlen); } *cert = buffer; buffer = NULL; *certlen = totobjlen; leave: xfree (buffer); return err; } /* Verify the PIN if required. */ static gpg_error_t verify_pin (app_t app, gpg_error_t (*pincb)(void*, const char *, char **), void *pincb_arg) { /* Note that force_chv1 is never set but we do it here anyway so that other applications may reuse this function. For example it makes sense to set force_chv1 for German signature law cards. NKS is very similar to the DINSIG draft standard. */ if (!app->did_chv1 || app->force_chv1 ) { char *pinvalue; int rc; rc = pincb (pincb_arg, "PIN", &pinvalue); if (rc) { log_info ("PIN callback returned error: %s\n", gpg_strerror (rc)); return rc; } /* The following limits are due to TCOS but also defined in the NKS specs. */ if (strlen (pinvalue) < 6) { log_error ("PIN is too short; minimum length is 6\n"); xfree (pinvalue); return gpg_error (GPG_ERR_BAD_PIN); } else if (strlen (pinvalue) > 16) { log_error ("PIN is too large; maximum length is 16\n"); xfree (pinvalue); return gpg_error (GPG_ERR_BAD_PIN); } /* Also it is possible to use a local PIN, we use the gloabl PIN for this application. */ rc = iso7816_verify (app->slot, 0, pinvalue, strlen (pinvalue)); if (rc) { if ( gpg_error (rc) == GPG_ERR_USE_CONDITIONS ) log_error (_("the NullPIN has not yet been changed\n")); else log_error ("verify PIN failed\n"); xfree (pinvalue); return rc; } app->did_chv1 = 1; xfree (pinvalue); } return 0; } /* Create the signature and return the allocated result in OUTDATA. If a PIN is required the PINCB will be used to ask for the PIN; that callback should return the PIN in an allocated buffer and store that in the 3rd argument. */ static gpg_error_t do_sign (app_t app, const char *keyidstr, int hashalgo, gpg_error_t (*pincb)(void*, const char *, char **), void *pincb_arg, const void *indata, size_t indatalen, unsigned char **outdata, size_t *outdatalen ) { static unsigned char sha1_prefix[15] = /* Object ID is 1.3.14.3.2.26 */ { 0x30, 0x21, 0x30, 0x09, 0x06, 0x05, 0x2b, 0x0e, 0x03, 0x02, 0x1a, 0x05, 0x00, 0x04, 0x14 }; static unsigned char rmd160_prefix[15] = /* Object ID is 1.3.36.3.2.1 */ { 0x30, 0x21, 0x30, 0x09, 0x06, 0x05, 0x2b, 0x24, 0x03, 0x02, 0x01, 0x05, 0x00, 0x04, 0x14 }; int rc, i; int fid; unsigned char data[35]; /* Must be large enough for a SHA-1 digest + the largest OID _prefix above. */ if (!keyidstr || !*keyidstr) return gpg_error (GPG_ERR_INV_VALUE); if (indatalen != 20 && indatalen != 16 && indatalen != 35) return gpg_error (GPG_ERR_INV_VALUE); /* Check that the provided ID is vaid. This is not really needed but we do it to to enforce correct usage by the caller. */ if (strncmp (keyidstr, "NKS-DF01.", 9) ) return gpg_error (GPG_ERR_INV_ID); keyidstr += 9; if (!hexdigitp (keyidstr) || !hexdigitp (keyidstr+1) || !hexdigitp (keyidstr+2) || !hexdigitp (keyidstr+3) || keyidstr[4]) return gpg_error (GPG_ERR_INV_ID); fid = xtoi_4 (keyidstr); for (i=0; filelist[i].fid; i++) if (filelist[i].iskeypair && filelist[i].fid == fid) break; if (!filelist[i].fid) return gpg_error (GPG_ERR_NOT_FOUND); if (!filelist[i].issignkey) return gpg_error (GPG_ERR_INV_ID); /* Prepare the DER object from INDATA. */ if (indatalen == 35) { /* Alright, the caller was so kind to send us an already prepared DER object. Check that it is waht we want and that it matches the hash algorithm. */ if (hashalgo == GCRY_MD_SHA1 && !memcmp (indata, sha1_prefix, 15)) ; else if (hashalgo == GCRY_MD_RMD160 && !memcmp (indata, rmd160_prefix,15)) ; else return gpg_error (GPG_ERR_UNSUPPORTED_ALGORITHM); memcpy (data, indata, indatalen); } else { if (hashalgo == GCRY_MD_SHA1) memcpy (data, sha1_prefix, 15); else if (hashalgo == GCRY_MD_RMD160) memcpy (data, rmd160_prefix, 15); else return gpg_error (GPG_ERR_UNSUPPORTED_ALGORITHM); memcpy (data+15, indata, indatalen); } rc = verify_pin (app, pincb, pincb_arg); if (!rc) rc = iso7816_compute_ds (app->slot, data, 35, outdata, outdatalen); return rc; } /* Decrypt the data in INDATA and return the allocated result in OUTDATA. If a PIN is required the PINCB will be used to ask for the PIN; it should return the PIN in an allocated buffer and put it into PIN. */ static gpg_error_t do_decipher (app_t app, const char *keyidstr, gpg_error_t (*pincb)(void*, const char *, char **), void *pincb_arg, const void *indata, size_t indatalen, unsigned char **outdata, size_t *outdatalen ) { static const unsigned char mse_parm[] = { 0x80, 1, 0x10, /* Select algorithm RSA. */ 0x84, 1, 0x81 /* Select local secret key 1 for decryption. */ }; int rc, i; int fid; if (!keyidstr || !*keyidstr || !indatalen) return gpg_error (GPG_ERR_INV_VALUE); /* Check that the provided ID is vaid. This is not really needed but we do it to to enforce correct usage by the caller. */ if (strncmp (keyidstr, "NKS-DF01.", 9) ) return gpg_error (GPG_ERR_INV_ID); keyidstr += 9; if (!hexdigitp (keyidstr) || !hexdigitp (keyidstr+1) || !hexdigitp (keyidstr+2) || !hexdigitp (keyidstr+3) || keyidstr[4]) return gpg_error (GPG_ERR_INV_ID); fid = xtoi_4 (keyidstr); for (i=0; filelist[i].fid; i++) if (filelist[i].iskeypair && filelist[i].fid == fid) break; if (!filelist[i].fid) return gpg_error (GPG_ERR_NOT_FOUND); if (!filelist[i].isenckey) return gpg_error (GPG_ERR_INV_ID); /* Do the TCOS specific MSE. */ rc = iso7816_manage_security_env (app->slot, 0xC1, 0xB8, mse_parm, sizeof mse_parm); if (!rc) rc = verify_pin (app, pincb, pincb_arg); if (!rc) rc = iso7816_decipher (app->slot, indata, indatalen, 0x81, outdata, outdatalen); return rc; } /* Select the NKS 2.0 application on the card in SLOT. */ gpg_error_t app_select_nks (APP app) { static char const aid[] = { 0xD2, 0x76, 0x00, 0x00, 0x03, 0x01, 0x02 }; int slot = app->slot; int rc; rc = iso7816_select_application (slot, aid, sizeof aid, 0); if (!rc) { app->apptype = "NKS"; app->fnc.learn_status = do_learn_status; app->fnc.readcert = do_readcert; app->fnc.getattr = NULL; app->fnc.setattr = NULL; app->fnc.genkey = NULL; app->fnc.sign = do_sign; app->fnc.auth = NULL; app->fnc.decipher = do_decipher; app->fnc.change_pin = NULL; app->fnc.check_pin = NULL; } return rc; }