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/* 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.
*/
#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;
int err;
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) {
*outlen = 2;
return CRYPT_BUFFER_OVERFLOW;
}
/* decode the packet header */
x = 0;
if ((in[x++] & 0x1F) != 0x06) {
return CRYPT_INVALID_PACKET;
}
/* get the length of the data */
y = inlen - x;
if ((err = der_decode_asn1_length(in + x, &y, &len)) != CRYPT_OK) {
return err;
}
x += y;
if ((len == 0) || (len > (inlen - x))) {
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) {
y++;
} else {
if (y == 0) {
words[0] = t / 40;
words[1] = t % 40;
y = 2;
} else {
words[y++] = t;
}
}
t = 0;
}
}
if (y > *outlen) {
err = CRYPT_BUFFER_OVERFLOW;
} else {
err = CRYPT_OK;
}
*outlen = y;
return err;
}
#endif
/* ref: $Format:%D$ */
/* git commit: $Format:%H$ */
/* commit time: $Format:%ai$ */
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