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Diffstat (limited to 'scd/app-help.c')
| -rw-r--r-- | scd/app-help.c | 209 |
1 files changed, 209 insertions, 0 deletions
diff --git a/scd/app-help.c b/scd/app-help.c new file mode 100644 index 0000000..4b8a024 --- /dev/null +++ b/scd/app-help.c @@ -0,0 +1,209 @@ +/* app-help.c - Application helper functions + * Copyright (C) 2004, 2009 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 3 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, see <https://www.gnu.org/licenses/>. + */ + +#include <config.h> +#include <errno.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> + +#include "scdaemon.h" +#include "app-common.h" +#include "iso7816.h" +#include "../common/tlv.h" + + +/* Count the number of bits, assuming the A represents an unsigned big + integer of length LEN bytes. If A is NULL a length of 0 is + returned. */ +unsigned int +app_help_count_bits (const unsigned char *a, size_t len) +{ + unsigned int n = len * 8; + int i; + + if (!a) + return 0; + + for (; len && !*a; len--, a++, n -=8) + ; + if (len) + { + for (i=7; i && !(*a & (1<<i)); i--) + n--; + } + return n; +} + + +/* Return the KEYGRIP for the canonical encoded public key (PK,PKLEN) + * as an hex encoded string in the user provided buffer HEXKEYGRIP + * which must be of at least 41 bytes. If R_PKEY is not NULL and the + * function succeeded, the S-expression representing the key is + * stored there. The caller needs to call gcry_sexp_release on + * that. */ +gpg_error_t +app_help_get_keygrip_string_pk (const void *pk, size_t pklen, char *hexkeygrip, + gcry_sexp_t *r_pkey) +{ + gpg_error_t err; + gcry_sexp_t s_pkey; + unsigned char array[KEYGRIP_LEN]; + + if (r_pkey) + *r_pkey = NULL; + + err = gcry_sexp_sscan (&s_pkey, NULL, pk, pklen); + if (err) + return err; /* Can't parse that S-expression. */ + if (!gcry_pk_get_keygrip (s_pkey, array)) + { + gcry_sexp_release (s_pkey); + return gpg_error (GPG_ERR_GENERAL); /* Failed to calculate the keygrip.*/ + } + + if (r_pkey) + *r_pkey = s_pkey; + else + gcry_sexp_release (s_pkey); + + bin2hex (array, KEYGRIP_LEN, hexkeygrip); + + return 0; +} + + +/* Return the KEYGRIP for the certificate CERT as an hex encoded + * string in the user provided buffer HEXKEYGRIP which must be of at + * least 41 bytes. If R_PKEY is not NULL and the function succeeded, + * the S-expression representing the key is stored there. The caller + * needs to call gcry_sexp_release on that. */ +gpg_error_t +app_help_get_keygrip_string (ksba_cert_t cert, char *hexkeygrip, + gcry_sexp_t *r_pkey) +{ + gpg_error_t err; + ksba_sexp_t p; + size_t n; + + if (r_pkey) + *r_pkey = NULL; + + p = ksba_cert_get_public_key (cert); + if (!p) + return gpg_error (GPG_ERR_BUG); + n = gcry_sexp_canon_len (p, 0, NULL, NULL); + if (!n) + return gpg_error (GPG_ERR_INV_SEXP); + err = app_help_get_keygrip_string_pk ((void*)p, n, hexkeygrip, r_pkey); + ksba_free (p); + return err; +} + + +/* Given the SLOT and the File ID FID, return the length of the + certificate contained in that file. Returns 0 if the file does not + exists or does not contain a certificate. If R_CERTOFF is not + NULL, the length the header will be stored at this address; thus to + parse the X.509 certificate a read should start at that offset. + + On success the file is still selected. +*/ +size_t +app_help_read_length_of_cert (int slot, int fid, size_t *r_certoff) +{ + gpg_error_t err; + unsigned char *buffer; + const unsigned char *p; + size_t buflen, n; + int class, tag, constructed, ndef; + size_t resultlen, objlen, hdrlen; + + err = iso7816_select_file (slot, fid, 0); + if (err) + { + log_info ("error selecting FID 0x%04X: %s\n", fid, gpg_strerror (err)); + return 0; + } + + err = iso7816_read_binary (slot, 0, 32, &buffer, &buflen); + if (err) + { + log_info ("error reading certificate from FID 0x%04X: %s\n", + fid, gpg_strerror (err)); + return 0; + } + + if (!buflen || *buffer == 0xff) + { + log_info ("no certificate contained in FID 0x%04X\n", fid); + xfree (buffer); + return 0; + } + + p = buffer; + n = buflen; + err = parse_ber_header (&p, &n, &class, &tag, &constructed, + &ndef, &objlen, &hdrlen); + if (err) + { + log_info ("error parsing certificate in FID 0x%04X: %s\n", + fid, gpg_strerror (err)); + xfree (buffer); + return 0; + } + + /* All certificates should commence with a SEQUENCE except for the + special ROOT CA which are enclosed in a SET. */ + if ( !(class == CLASS_UNIVERSAL && constructed + && (tag == TAG_SEQUENCE || tag == TAG_SET))) + { + log_info ("data at FID 0x%04X does not look like a certificate\n", fid); + return 0; + } + + resultlen = objlen + hdrlen; + if (r_certoff) + { + /* The callers want the offset to the actual certificate. */ + *r_certoff = hdrlen; + + err = parse_ber_header (&p, &n, &class, &tag, &constructed, + &ndef, &objlen, &hdrlen); + if (err) + return 0; + + if (class == CLASS_UNIVERSAL && tag == TAG_OBJECT_ID && !constructed) + { + /* The certificate seems to be contained in a + userCertificate container. Assume the following sequence + is the certificate. */ + *r_certoff += hdrlen + objlen; + if (*r_certoff > resultlen) + { + *r_certoff = 0; + return 0; /* That should never happen. */ + } + } + else + *r_certoff = 0; + } + + return resultlen; +} |