mirror of
git://git.gnupg.org/gnupg.git
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108 lines
2.8 KiB
C
108 lines
2.8 KiB
C
/* pka.c - DNS Public Key Association RR access
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* Copyright (C) 2005, 2009 Free Software Foundation, Inc.
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*
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* This file is part of GnuPG.
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*
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* This file is free software; you can redistribute it and/or modify
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* it under the terms of either
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*
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* - the GNU Lesser General Public License as published by the Free
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* Software Foundation; either version 3 of the License, or (at
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* your option) any later version.
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*
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* or
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*
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* - the GNU General Public License as published by the Free
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* Software Foundation; either version 2 of the License, or (at
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* your option) any later version.
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*
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* or both in parallel, as here.
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*
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* This file is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, see <http://www.gnu.org/licenses/>.
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*/
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#include <config.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include "util.h"
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#include "mbox-util.h"
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#include "dns-cert.h"
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#include "pka.h"
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/* For the given email ADDRESS lookup the PKA information in the DNS.
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On success the fingerprint is stored at FPRBUF and the URI will be
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returned in an allocated buffer. Note that the URI might be a zero
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length string as this information is optional. Caller must xfree
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the returned string. FPRBUFLEN gives the size of the expected
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fingerprint (usually 20).
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On error NULL is returned and the FPRBUF is not defined. */
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char *
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get_pka_info (const char *address, void *fprbuf, size_t fprbuflen)
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{
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char *result = NULL;
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char *mbox;
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char *domain; /* Points to mbox. */
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char hashbuf[20];
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char *hash = NULL;
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char *name = NULL;
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unsigned char *fpr = NULL;
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size_t fpr_len;
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char *url = NULL;
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mbox = mailbox_from_userid (address);
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if (!mbox)
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goto leave;
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domain = strchr (mbox, '@');
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if (!domain)
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goto leave;
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*domain++ = 0;
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gcry_md_hash_buffer (GCRY_MD_SHA1, hashbuf, mbox, strlen (mbox));
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hash = zb32_encode (hashbuf, 8*20);
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if (!hash)
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goto leave;
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name = strconcat (hash, "._pka.", domain, NULL);
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if (!name)
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goto leave;
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if (get_dns_cert (name, DNS_CERTTYPE_IPGP, NULL, &fpr, &fpr_len, &url))
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goto leave;
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if (!fpr)
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goto leave;
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/* Return the fingerprint. */
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if (fpr_len != fprbuflen)
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{
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/* fprintf (stderr, "get_dns_cert failed: fprlen (%zu/%zu)\n", */
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/* fpr_len, fprbuflen); */
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goto leave;
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}
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memcpy (fprbuf, fpr, fpr_len);
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/* We return the URL or an empty string. */
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if (!url)
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url = xtrycalloc (1, 1);
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result = url;
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url = NULL;
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leave:
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xfree (fpr);
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xfree (url);
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xfree (name);
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xfree (hash);
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xfree (mbox);
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return result;
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}
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