diff options
Diffstat (limited to 'libtomcrypt/pk/asn1/der/object_identifier/der_decode_object_identifier.c')
-rw-r--r-- | libtomcrypt/pk/asn1/der/object_identifier/der_decode_object_identifier.c | 99 |
1 files changed, 99 insertions, 0 deletions
diff --git a/libtomcrypt/pk/asn1/der/object_identifier/der_decode_object_identifier.c b/libtomcrypt/pk/asn1/der/object_identifier/der_decode_object_identifier.c new file mode 100644 index 0000000..cdd296d --- /dev/null +++ b/libtomcrypt/pk/asn1/der/object_identifier/der_decode_object_identifier.c @@ -0,0 +1,99 @@ +/* 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://libtom.org + */ +#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: 1.6 $ */ +/* $Date: 2006/12/28 01:27:24 $ */ |