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https://github.com/Laupetin/OpenAssetTools.git
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145 lines
3.6 KiB
C
145 lines
3.6 KiB
C
/* LibTomCrypt, modular cryptographic library -- Tom St Denis
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*
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* LibTomCrypt is a library that provides various cryptographic
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* algorithms in a highly modular and flexible manner.
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*
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* The library is free for all purposes without any express
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* guarantee it works.
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*/
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#include "tomcrypt.h"
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/**
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@file der_decode_generalizedtime.c
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ASN.1 DER, decode a GeneralizedTime, Steffen Jaeckel
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Based on der_decode_utctime.c
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*/
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#ifdef LTC_DER
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static int _char_to_int(unsigned char x)
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{
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switch (x) {
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case '0': return 0;
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case '1': return 1;
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case '2': return 2;
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case '3': return 3;
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case '4': return 4;
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case '5': return 5;
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case '6': return 6;
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case '7': return 7;
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case '8': return 8;
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case '9': return 9;
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default: return 100;
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}
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}
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#define DECODE_V(y, max) do {\
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y = _char_to_int(buf[x])*10 + _char_to_int(buf[x+1]); \
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if (y >= max) return CRYPT_INVALID_PACKET; \
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x += 2; \
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} while(0)
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#define DECODE_V4(y, max) do {\
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y = _char_to_int(buf[x])*1000 + _char_to_int(buf[x+1])*100 + _char_to_int(buf[x+2])*10 + _char_to_int(buf[x+3]); \
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if (y >= max) return CRYPT_INVALID_PACKET; \
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x += 4; \
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} while(0)
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/**
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Decodes a Generalized time structure in DER format (reads all 6 valid encoding formats)
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@param in Input buffer
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@param inlen Length of input buffer in octets
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@param out [out] Destination of Generalized time structure
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@return CRYPT_OK if successful
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*/
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int der_decode_generalizedtime(const unsigned char *in, unsigned long *inlen,
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ltc_generalizedtime *out)
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{
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unsigned char buf[32];
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unsigned long x;
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int y;
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LTC_ARGCHK(in != NULL);
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LTC_ARGCHK(inlen != NULL);
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LTC_ARGCHK(out != NULL);
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/* check header */
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if (*inlen < 2UL || (in[1] >= sizeof(buf)) || ((in[1] + 2UL) > *inlen)) {
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return CRYPT_INVALID_PACKET;
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}
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/* decode the string */
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for (x = 0; x < in[1]; x++) {
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y = der_ia5_value_decode(in[x+2]);
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if (y == -1) {
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return CRYPT_INVALID_PACKET;
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}
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if (!((y >= '0' && y <= '9')
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|| y == 'Z' || y == '.'
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|| y == '+' || y == '-')) {
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return CRYPT_INVALID_PACKET;
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}
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buf[x] = y;
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}
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*inlen = 2 + x;
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if (x < 15) {
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return CRYPT_INVALID_PACKET;
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}
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/* possible encodings are
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YYYYMMDDhhmmssZ
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YYYYMMDDhhmmss+hh'mm'
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YYYYMMDDhhmmss-hh'mm'
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YYYYMMDDhhmmss.fsZ
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YYYYMMDDhhmmss.fs+hh'mm'
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YYYYMMDDhhmmss.fs-hh'mm'
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So let's do a trivial decode upto [including] ss
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*/
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x = 0;
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DECODE_V4(out->YYYY, 10000);
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DECODE_V(out->MM, 13);
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DECODE_V(out->DD, 32);
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DECODE_V(out->hh, 24);
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DECODE_V(out->mm, 60);
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DECODE_V(out->ss, 60);
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/* clear fractional seconds info */
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out->fs = 0;
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/* now is it Z or . */
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if (buf[x] == 'Z') {
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return CRYPT_OK;
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} else if (buf[x] == '.') {
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x++;
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while (buf[x] >= '0' && buf[x] <= '9') {
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unsigned fs = out->fs;
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if (x >= sizeof(buf)) return CRYPT_INVALID_PACKET;
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out->fs *= 10;
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out->fs += _char_to_int(buf[x]);
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if (fs > out->fs) return CRYPT_OVERFLOW;
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x++;
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}
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}
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/* now is it Z, +, - */
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if (buf[x] == 'Z') {
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return CRYPT_OK;
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} else if (buf[x] == '+' || buf[x] == '-') {
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out->off_dir = (buf[x++] == '+') ? 0 : 1;
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DECODE_V(out->off_hh, 24);
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DECODE_V(out->off_mm, 60);
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return CRYPT_OK;
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} else {
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return CRYPT_INVALID_PACKET;
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}
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}
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#endif
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/* ref: HEAD -> master, tag: v1.18.2 */
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/* git commit: 7e7eb695d581782f04b24dc444cbfde86af59853 */
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/* commit time: 2018-07-01 22:49:01 +0200 */
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