der_decode_ia5_string.c revision 29698e296e3fd1474a362fbd229bca888175bb66 
1/* LibTomCrypt, modular cryptographic library -- Tom St Denis
2 *
3 * LibTomCrypt is a library that provides various cryptographic
4 * algorithms in a highly modular and flexible manner.
5 *
6 * The library is free for all purposes without any express
7 * guarantee it works.
8 *
9 * Tom St Denis, tomstdenis@gmail.com, http://libtomcrypt.com
10 */
11#include "tomcrypt.h"
12
13/**
14  @file der_decode_ia5_string.c
15  ASN.1 DER, encode a IA5 STRING, Tom St Denis
16*/
17
18
19#ifdef LTC_DER
20
21/**
22  Store a IA5 STRING
23  @param in      The DER encoded IA5 STRING
24  @param inlen   The size of the DER IA5 STRING
25  @param out     [out] The array of octets stored (one per char)
26  @param outlen  [in/out] The number of octets stored
27  @return CRYPT_OK if successful
28*/
29int der_decode_ia5_string(const unsigned char *in, unsigned long inlen,
30                                unsigned char *out, unsigned long *outlen)
31{
32   unsigned long x, y, len;
33   int           t;
34
35   LTC_ARGCHK(in     != NULL);
36   LTC_ARGCHK(out    != NULL);
37   LTC_ARGCHK(outlen != NULL);
38
39   /* must have header at least */
40   if (inlen < 2) {
41      return CRYPT_INVALID_PACKET;
42   }
43
44   /* check for 0x16 */
45   if ((in[0] & 0x1F) != 0x16) {
46      return CRYPT_INVALID_PACKET;
47   }
48   x = 1;
49
50   /* decode the length */
51   if (in[x] & 0x80) {
52      /* valid # of bytes in length are 1,2,3 */
53      y = in[x] & 0x7F;
54      if ((y == 0) || (y > 3) || ((x + y) > inlen)) {
55         return CRYPT_INVALID_PACKET;
56      }
57
58      /* read the length in */
59      len = 0;
60      ++x;
61      while (y--) {
62         len = (len << 8) | in[x++];
63      }
64   } else {
65      len = in[x++] & 0x7F;
66   }
67
68   /* is it too long? */
69   if (len > *outlen) {
70      *outlen = len;
71      return CRYPT_BUFFER_OVERFLOW;
72   }
73
74   if (len + x > inlen) {
75      return CRYPT_INVALID_PACKET;
76   }
77
78   /* read the data */
79   for (y = 0; y < len; y++) {
80       t = der_ia5_value_decode(in[x++]);
81       if (t == -1) {
82           return CRYPT_INVALID_ARG;
83       }
84       out[y] = t;
85   }
86
87   *outlen = y;
88
89   return CRYPT_OK;
90}
91
92#endif
93
94/* $Source: /cvs/libtom/libtomcrypt/src/pk/asn1/der/ia5/der_decode_ia5_string.c,v $ */
95/* $Revision: 1.3 $ */
96/* $Date: 2006/06/16 21:53:41 $ */
97