| /* LibTomCrypt, modular cryptographic library -- Tom St Denis |
| * |
| * LibTomCrypt is a library that provides various cryptographic |
| * algorithms in a highly modular and flexible manner. |
| * |
| * The library is free for all purposes without any express |
| * guarantee it works. |
| * |
| * Tom St Denis, tomstdenis@gmail.com, http://libtomcrypt.com |
| */ |
| #include "tomcrypt.h" |
| |
| /** |
| @file der_decode_object_identifier.c |
| ASN.1 DER, Decode Object Identifier, Tom St Denis |
| */ |
| |
| #ifdef LTC_DER |
| /** |
| Decode OID data and store the array of integers in words |
| @param in The OID DER encoded data |
| @param inlen The length of the OID data |
| @param words [out] The destination of the OID words |
| @param outlen [in/out] The number of OID words |
| @return CRYPT_OK if successful |
| */ |
| int der_decode_object_identifier(const unsigned char *in, unsigned long inlen, |
| unsigned long *words, unsigned long *outlen) |
| { |
| unsigned long x, y, t, len; |
| |
| LTC_ARGCHK(in != NULL); |
| LTC_ARGCHK(words != NULL); |
| LTC_ARGCHK(outlen != NULL); |
| |
| /* header is at least 3 bytes */ |
| if (inlen < 3) { |
| return CRYPT_INVALID_PACKET; |
| } |
| |
| /* must be room for at least two words */ |
| if (*outlen < 2) { |
| return CRYPT_BUFFER_OVERFLOW; |
| } |
| |
| /* decode the packet header */ |
| x = 0; |
| if ((in[x++] & 0x1F) != 0x06) { |
| return CRYPT_INVALID_PACKET; |
| } |
| |
| /* get the length */ |
| if (in[x] < 128) { |
| len = in[x++]; |
| } else { |
| if (in[x] < 0x81 || in[x] > 0x82) { |
| return CRYPT_INVALID_PACKET; |
| } |
| y = in[x++] & 0x7F; |
| len = 0; |
| while (y--) { |
| len = (len << 8) | (unsigned long)in[x++]; |
| } |
| } |
| |
| if (len < 1 || (len + x) > inlen) { |
| return CRYPT_INVALID_PACKET; |
| } |
| |
| /* decode words */ |
| y = 0; |
| t = 0; |
| while (len--) { |
| t = (t << 7) | (in[x] & 0x7F); |
| if (!(in[x++] & 0x80)) { |
| /* store t */ |
| if (y >= *outlen) { |
| return CRYPT_BUFFER_OVERFLOW; |
| } |
| if (y == 0) { |
| words[0] = t / 40; |
| words[1] = t % 40; |
| y = 2; |
| } else { |
| words[y++] = t; |
| } |
| t = 0; |
| } |
| } |
| |
| *outlen = y; |
| return CRYPT_OK; |
| } |
| |
| #endif |
| |
| /* $Source: /cvs/libtom/libtomcrypt/src/pk/asn1/der/object_identifier/der_decode_object_identifier.c,v $ */ |
| /* $Revision: 1.5 $ */ |
| /* $Date: 2006/11/21 00:18:23 $ */ |