LCOV - code coverage report
Current view: top level - src - oid.c (source / functions) Hit Total Coverage
Test: coverage.info Lines: 38 104 36.5 %
Date: 2016-09-12 12:51:24 Functions: 2 5 40.0 %

          Line data    Source code
       1             : /* oid.c - Object identifier helper functions
       2             :  * Copyright (C) 2001, 2009, 2012 g10 Code GmbH
       3             :  *
       4             :  * This file is part of KSBA.
       5             :  *
       6             :  * KSBA is free software; you can redistribute it and/or modify
       7             :  * it under the terms of either
       8             :  *
       9             :  *   - the GNU Lesser General Public License as published by the Free
      10             :  *     Software Foundation; either version 3 of the License, or (at
      11             :  *     your option) any later version.
      12             :  *
      13             :  * or
      14             :  *
      15             :  *   - the GNU General Public License as published by the Free
      16             :  *     Software Foundation; either version 2 of the License, or (at
      17             :  *     your option) any later version.
      18             :  *
      19             :  * or both in parallel, as here.
      20             :  *
      21             :  * KSBA is distributed in the hope that it will be useful, but WITHOUT
      22             :  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
      23             :  * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public
      24             :  * License for more details.
      25             :  *
      26             :  * You should have received a copies of the GNU General Public License
      27             :  * and the GNU Lesser General Public License along with this program;
      28             :  * if not, see <http://www.gnu.org/licenses/>.
      29             :  */
      30             : 
      31             : #include <config.h>
      32             : #include <stdio.h>
      33             : #include <stdlib.h>
      34             : #include <string.h>
      35             : #include <assert.h>
      36             : 
      37             : #include "util.h"
      38             : #include "asn1-func.h"
      39             : #include "convert.h"
      40             : 
      41             : 
      42             : 
      43             : /**
      44             :  * ksba_oid_to_str:
      45             :  * @buffer: A BER encoded OID
      46             :  * @length: The length of this OID
      47             :  *
      48             :  * Take a buffer with an object identifier in BER encoding and return
      49             :  * a string representing this OID.  We do not use the ASN.1 syntax
      50             :  * here but delimit the arcs with dots, so it is easier to parse in
      51             :  * most cases.  This dotted-decimal notation is also known as LDAPOID
      52             :  * string and described in RFC-2251.
      53             :  *
      54             :  * The function returns an empty string for an empty buffer and does
      55             :  * no interpretation of the OID.  The caller must free the returned
      56             :  * string using ksba_free() or the function he has registered as a
      57             :  * replacement.
      58             :  *
      59             :  *
      60             :  * Return value: A allocated string or NULL in case of memory problem.
      61             :  **/
      62             : char *
      63          55 : ksba_oid_to_str (const char *buffer, size_t length)
      64             : {
      65          55 :   const unsigned char *buf = buffer;
      66             :   char *string, *p;
      67          55 :   int n = 0;
      68             :   unsigned long val, valmask;
      69             : 
      70          55 :   valmask = (unsigned long)0xfe << (8 * (sizeof (valmask) - 1));
      71             : 
      72             :   /* To calculate the length of the string we can safely assume an
      73             :      upper limit of 3 decimal characters per byte.  Two extra bytes
      74             :      account for the special first octect */
      75          55 :   string = p = xtrymalloc (length*(1+3)+2+1);
      76          55 :   if (!string)
      77           0 :     return NULL;
      78          55 :   if (!length)
      79             :     {
      80           1 :       *p = 0;
      81           1 :       return string;
      82             :     }
      83             : 
      84          54 :   if (buf[0] < 40)
      85           2 :     p += sprintf (p, "0.%d", buf[n]);
      86          52 :   else if (buf[0] < 80)
      87          11 :     p += sprintf (p, "1.%d", buf[n]-40);
      88             :   else {
      89          41 :     val = buf[n] & 0x7f;
      90          88 :     while ( (buf[n]&0x80) && ++n < length )
      91             :       {
      92           6 :         if ( (val & valmask) )
      93           0 :           goto badoid;  /* Overflow.  */
      94           6 :         val <<= 7;
      95           6 :         val |= buf[n] & 0x7f;
      96             :       }
      97          41 :     if (val < 80)
      98           2 :       goto badoid;
      99          39 :     val -= 80;
     100          39 :     sprintf (p, "2.%lu", val);
     101          39 :     p += strlen (p);
     102             :   }
     103         219 :   for (n++; n < length; n++)
     104             :     {
     105         167 :       val = buf[n] & 0x7f;
     106         398 :       while ( (buf[n]&0x80) && ++n < length )
     107             :         {
     108          64 :           if ( (val & valmask) )
     109           0 :             goto badoid;  /* Overflow.  */
     110          64 :           val <<= 7;
     111          64 :           val |= buf[n] & 0x7f;
     112             :         }
     113         167 :       sprintf (p, ".%lu", val);
     114         167 :       p += strlen (p);
     115             :     }
     116             : 
     117          52 :   *p = 0;
     118          52 :   return string;
     119             : 
     120             :  badoid:
     121             :   /* Return a special OID (gnu.gnupg.badoid) to indicate the error
     122             :      case.  The OID is broken and thus we return one which can't do
     123             :      any harm.  Formally this does not need to be a bad OID but an OID
     124             :      with an arc that can't be represented in a 32 bit word is more
     125             :      than likely corrupt.  */
     126           2 :   xfree (string);
     127           2 :   return xtrystrdup ("1.3.6.1.4.1.11591.2.12242973");
     128             : }
     129             : 
     130             : 
     131             : /* Take the OID at NODE and return it in string format */
     132             : char *
     133          20 : _ksba_oid_node_to_str (const unsigned char *image, AsnNode node)
     134             : {
     135          20 :   if (!node || node->type != TYPE_OBJECT_ID || node->off == -1)
     136           0 :     return NULL;
     137          20 :   return ksba_oid_to_str (image+node->off + node->nhdr, node->len);
     138             : }
     139             : 
     140             : 
     141             : 
     142             : static size_t
     143           0 : make_flagged_int (unsigned long value, char *buf, size_t buflen)
     144             : {
     145           0 :   int more = 0;
     146             :   int shift;
     147             : 
     148             :   /* fixme: figure out the number of bits in an ulong and start with
     149             :      that value as shift (after making it a multiple of 7) a more
     150             :      straigtforward implementation is to do it in reverse order using
     151             :      a temporary buffer - saves a lot of compares */
     152           0 :   for (more=0, shift=28; shift > 0; shift -= 7)
     153             :     {
     154           0 :       if (more || value >= (1<<shift))
     155             :         {
     156           0 :           buf[buflen++] = 0x80 | (value >> shift);
     157           0 :           value -= (value >> shift) << shift;
     158           0 :           more = 1;
     159             :         }
     160             :     }
     161           0 :   buf[buflen++] = value;
     162           0 :   return buflen;
     163             : }
     164             : 
     165             : 
     166             : /**
     167             :  * ksba_oid_from_str:
     168             :  * @string: A string with the OID in dotted decimal form
     169             :  * @rbuf:   Returns the DER encoded OID
     170             :  * @rlength: and its length
     171             :  *
     172             :  * Convertes the OID given in dotted decimal form to an DER encoding
     173             :  * and returns it in allocated buffer rbuf and its length in rlength.
     174             :  * rbuf is set to NULL in case of an error is returned.
     175             :  * Scanning stops at the first white space.
     176             : 
     177             :  * The caller must free the returned buffer using ksba_free() or the
     178             :  * function he has registered as a replacement.
     179             :  *
     180             :  * Return value: 0 on success or an error value
     181             :  **/
     182             : gpg_error_t
     183           0 : ksba_oid_from_str (const char *string, unsigned char **rbuf, size_t *rlength)
     184             : {
     185             :   unsigned char *buf;
     186             :   size_t buflen;
     187             :   unsigned long val1, val;
     188             :   const char *endp;
     189             :   int arcno;
     190             : 
     191           0 :   if (!string || !rbuf || !rlength)
     192           0 :     return gpg_error (GPG_ERR_INV_VALUE);
     193           0 :   *rbuf = NULL;
     194           0 :   *rlength = 0;
     195             : 
     196             :   /* we allow the OID to be prefixed with either "oid." or "OID." */
     197           0 :   if ( !strncmp (string, "oid.", 4) || !strncmp (string, "OID.", 4))
     198           0 :     string += 4;
     199             : 
     200           0 :   if (!*string)
     201           0 :     return gpg_error (GPG_ERR_INV_VALUE);
     202             : 
     203             :   /* we can safely assume that the encoded OID is shorter than the string */
     204           0 :   buf = xtrymalloc ( strlen(string) + 2);
     205           0 :   if (!buf)
     206           0 :     return gpg_error (GPG_ERR_ENOMEM);
     207           0 :   buflen = 0;
     208             : 
     209           0 :   val1 = 0; /* avoid compiler warnings */
     210           0 :   arcno = 0;
     211             :   do {
     212           0 :     arcno++;
     213           0 :     val = strtoul (string, (char**)&endp, 10);
     214           0 :     if (!digitp (string) || !(*endp == '.' || !*endp))
     215             :       {
     216           0 :         xfree (buf);
     217           0 :         return gpg_error (GPG_ERR_INV_OID_STRING);
     218             :       }
     219           0 :     if (*endp == '.')
     220           0 :       string = endp+1;
     221             : 
     222           0 :     if (arcno == 1)
     223             :       {
     224           0 :         if (val > 2)
     225           0 :           break; /* not allowed, error catched below */
     226           0 :         val1 = val;
     227             :       }
     228           0 :     else if (arcno == 2)
     229             :       { /* need to combine the first to arcs in one octet */
     230           0 :         if (val1 < 2)
     231             :           {
     232           0 :             if (val > 39)
     233             :               {
     234           0 :                 xfree (buf);
     235           0 :                 return gpg_error (GPG_ERR_INV_OID_STRING);
     236             :               }
     237           0 :             buf[buflen++] = val1*40 + val;
     238             :           }
     239             :         else
     240             :           {
     241           0 :             val += 80;
     242           0 :             buflen = make_flagged_int (val, buf, buflen);
     243             :           }
     244             :       }
     245             :     else
     246             :       {
     247           0 :         buflen = make_flagged_int (val, buf, buflen);
     248             :       }
     249           0 :   } while (*endp == '.');
     250             : 
     251           0 :   if (arcno == 1)
     252             :     { /* it is not possible to encode only the first arc */
     253           0 :       xfree (buf);
     254           0 :       return gpg_error (GPG_ERR_INV_OID_STRING);
     255             :     }
     256             : 
     257           0 :   *rbuf = buf;
     258           0 :   *rlength = buflen;
     259           0 :   return 0;
     260             : }
     261             : 
     262             : 
     263             : /* Convert the string in BUFFER which is of length BUFLEN to its DER
     264             :    encoding and returns it in a new allocated buffer RBUF and its
     265             :    length in RLENGTH.  RBUF is set to NULL if an error is returned.
     266             :    The caller must free the returned buffer using ksba_free() or the
     267             :    function he has registered as a replacement.  */
     268             : gpg_error_t
     269           0 : _ksba_oid_from_buf (const void *buffer, size_t buflen,
     270             :                     unsigned char **rbuf, size_t *rlength)
     271             : {
     272             :   gpg_error_t err;
     273             :   char *string;
     274             : 
     275           0 :   string = xtrymalloc (buflen+1);
     276           0 :   if (!string)
     277             :     {
     278           0 :       *rbuf = NULL;
     279           0 :       *rlength = 0;
     280           0 :       return gpg_error_from_syserror ();
     281             :     }
     282           0 :   memcpy (string, buffer, buflen);
     283           0 :   string[buflen] = 0;
     284           0 :   err = ksba_oid_from_str (string, rbuf, rlength);
     285           0 :   xfree (string);
     286           0 :   return err;
     287             : }

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