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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 */
der_decode_ia5_string(const unsigned char * in,unsigned long inlen,unsigned char * out,unsigned long * outlen)29 int 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