diff options
Diffstat (limited to 'g13/keyblob.c')
| -rw-r--r-- | g13/keyblob.c | 207 |
1 files changed, 207 insertions, 0 deletions
diff --git a/g13/keyblob.c b/g13/keyblob.c new file mode 100644 index 0000000..1fb9be7 --- /dev/null +++ b/g13/keyblob.c @@ -0,0 +1,207 @@ +/* keyblob.c - Keyblob parser and builder. + * Copyright (C) 2009 Free Software Foundation, Inc. + * Copyright (C) 2015-2016 Werner Koch + * + * 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 <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <errno.h> +#include <unistd.h> +#include <sys/stat.h> +#include <assert.h> + +#include "g13.h" +#include "mount.h" + +#include "keyblob.h" +#include "../common/sysutils.h" +#include "../common/host2net.h" + + +/* Parse the header prefix and return the length of the entire header. */ +static gpg_error_t +parse_header (const char *filename, + const unsigned char *packet, size_t packetlen, + size_t *r_headerlen) +{ + unsigned int len; + + if (packetlen != 32) + return gpg_error (GPG_ERR_BUG); + + len = buf32_to_uint (packet+2); + if (packet[0] != (0xc0|61) || len < 26 + || memcmp (packet+6, "GnuPG/G13", 10)) + { + log_error ("file '%s' is not valid container\n", filename); + return gpg_error (GPG_ERR_INV_OBJ); + } + if (packet[16] != 1) + { + log_error ("unknown version %u of container '%s'\n", + (unsigned int)packet[16], filename); + return gpg_error (GPG_ERR_INV_OBJ); + } + if (packet[17] || packet[18] + || packet[26] || packet[27] || packet[28] || packet[29] + || packet[30] || packet[31]) + log_info ("WARNING: unknown meta information in '%s'\n", filename); + if (packet[19]) + log_info ("WARNING: OS flag is not supported in '%s'\n", filename); + if (packet[24] > 1 ) + log_info ("Note: meta data copies in '%s' are ignored\n", filename); + + len = buf32_to_uint (packet+20); + + /* Do a basic sanity check on the length. */ + if (len < 32 || len > 1024*1024) + { + log_error ("bad length given in container '%s'\n", filename); + return gpg_error (GPG_ERR_INV_OBJ); + } + + *r_headerlen = len; + return 0; +} + + +/* Read the prefix of the keyblob and do some basic parsing. On + success returns an open estream file at R_FP and the length of the + header at R_HEADERLEN. */ +static gpg_error_t +read_keyblob_prefix (const char *filename, estream_t *r_fp, size_t *r_headerlen) +{ + gpg_error_t err; + estream_t fp; + unsigned char packet[32]; + + *r_fp = NULL; + + fp = es_fopen (filename, "rb"); + if (!fp) + { + err = gpg_error_from_syserror (); + log_error ("error reading '%s': %s\n", filename, gpg_strerror (err)); + return err; + } + + /* Read the header. It is defined as 32 bytes thus we read it in one go. */ + if (es_fread (packet, 32, 1, fp) != 1) + { + err = gpg_error_from_syserror (); + log_error ("error reading the header of '%s': %s\n", + filename, gpg_strerror (err)); + es_fclose (fp); + return err; + } + + err = parse_header (filename, packet, 32, r_headerlen); + if (err) + es_fclose (fp); + else + *r_fp = fp; + + return err; +} + + + +/* + * Test whether the container with name FILENAME is a suitable G13 + * container. This function may even be called on a mounted + * container. + */ +gpg_error_t +g13_is_container (ctrl_t ctrl, const char *filename) +{ + gpg_error_t err; + estream_t fp = NULL; + size_t dummy; + + (void)ctrl; + + /* Read just the prefix of the header. */ + err = read_keyblob_prefix (filename, &fp, &dummy); + if (!err) + es_fclose (fp); + return err; +} + + +/* + * Read the keyblob at FILENAME. The caller should have acquired a + * lockfile and checked that the file exists. + */ +gpg_error_t +g13_keyblob_read (const char *filename, + void **r_enckeyblob, size_t *r_enckeybloblen) +{ + gpg_error_t err; + estream_t fp = NULL; + size_t headerlen = 0; + size_t msglen; + void *msg = NULL; + + *r_enckeyblob = NULL; + *r_enckeybloblen = 0; + + err = read_keyblob_prefix (filename, &fp, &headerlen); + if (err) + goto leave; + + if (opt.verbose) + log_info ("header length of '%s' is %zu\n", filename, headerlen); + + /* Read everything including the padding. We should eventually do a + regular OpenPGP parsing to detect the padding packet and pass + only the actual used OpenPGP data to the engine. This is in + particular required when supporting CMS which will be + encapsulated in an OpenPGP packet. */ + assert (headerlen >= 32); + msglen = headerlen - 32; + if (!msglen) + { + err = gpg_error (GPG_ERR_NO_DATA); + goto leave; + } + msg = xtrymalloc (msglen); + if (!msglen) + { + err = gpg_error_from_syserror (); + goto leave; + } + if (es_fread (msg, msglen, 1, fp) != 1) + { + err = gpg_error_from_syserror (); + log_error ("error reading keyblob of '%s': %s\n", + filename, gpg_strerror (err)); + goto leave; + } + + *r_enckeyblob = msg; + msg = NULL; + *r_enckeybloblen = msglen; + + leave: + xfree (msg); + es_fclose (fp); + + return err; +} |