-/*-
- * Copyright (c) 2003, 2004 Lev Walkin <vlm@lionet.info>. All rights reserved.
- * Redistribution and modifications are permitted subject to BSD license.
- */
-#include <asn_internal.h>
-#include <ber_tlv_length.h>
-#include <ber_tlv_tag.h>
-
-ssize_t
-ber_fetch_length(int _is_constructed, const void *bufptr, size_t size,
- ber_tlv_len_t *len_r) {
- const uint8_t *buf = (const uint8_t *)bufptr;
- unsigned oct;
-
- if(size == 0)
- return 0; /* Want more */
-
- oct = *(const uint8_t *)buf;
- if((oct & 0x80) == 0) {
- /*
- * Short definite length.
- */
- *len_r = oct; /* & 0x7F */
- return 1;
- } else {
- ber_tlv_len_t len;
- size_t skipped;
-
- if(_is_constructed && oct == 0x80) {
- *len_r = -1; /* Indefinite length */
- return 1;
- }
-
- if(oct == 0xff) {
- /* Reserved in standard for future use. */
- return -1;
- }
-
- oct &= 0x7F; /* Leave only the 7 LS bits */
- for(len = 0, buf++, skipped = 1;
- oct && (++skipped <= size); buf++, oct--) {
-
- len = (len << 8) | *buf;
- if(len < 0
- || (len >> ((8 * sizeof(len)) - 8) && oct > 1)) {
- /*
- * Too large length value.
- */
- return -1;
- }
- }
-
- if(oct == 0) {
- ber_tlv_len_t lenplusepsilon = (size_t)len + 1024;
- /*
- * Here length may be very close or equal to 2G.
- * However, the arithmetics used in some decoders
- * may add some (small) quantities to the length,
- * to check the resulting value against some limits.
- * This may result in integer wrap-around, which
- * we try to avoid by checking it earlier here.
- */
- if(lenplusepsilon < 0) {
- /* Too large length value */
- return -1;
- }
-
- *len_r = len;
- return skipped;
- }
-
- return 0; /* Want more */
- }
-
-}
-
-ssize_t
-ber_skip_length(asn_codec_ctx_t *opt_codec_ctx,
- int _is_constructed, const void *ptr, size_t size) {
- ber_tlv_len_t vlen; /* Length of V in TLV */
- ssize_t tl; /* Length of L in TLV */
- ssize_t ll; /* Length of L in TLV */
- size_t skip;
-
- /*
- * Make sure we didn't exceed the maximum stack size.
- */
- if(_ASN_STACK_OVERFLOW_CHECK(opt_codec_ctx))
- return -1;
-
- /*
- * Determine the size of L in TLV.
- */
- ll = ber_fetch_length(_is_constructed, ptr, size, &vlen);
- if(ll <= 0) return ll;
-
- /*
- * Definite length.
- */
- if(vlen >= 0) {
- skip = ll + vlen;
- if(skip > size)
- return 0; /* Want more */
- return skip;
- }
-
- /*
- * Indefinite length!
- */
- ASN_DEBUG("Skipping indefinite length");
- for(skip = ll, ptr = ((const char *)ptr) + ll, size -= ll;;) {
- ber_tlv_tag_t tag;
-
- /* Fetch the tag */
- tl = ber_fetch_tag(ptr, size, &tag);
- if(tl <= 0) return tl;
-
- ll = ber_skip_length(opt_codec_ctx,
- BER_TLV_CONSTRUCTED(ptr),
- ((const char *)ptr) + tl, size - tl);
- if(ll <= 0) return ll;
-
- skip += tl + ll;
-
- /*
- * This may be the end of the indefinite length structure,
- * two consecutive 0 octets.
- * Check if it is true.
- */
- if(((const uint8_t *)ptr)[0] == 0
- && ((const uint8_t *)ptr)[1] == 0)
- return skip;
-
- ptr = ((const char *)ptr) + tl + ll;
- size -= tl + ll;
- }
-
- /* UNREACHABLE */
-}
-
-size_t
-der_tlv_length_serialize(ber_tlv_len_t len, void *bufp, size_t size) {
- size_t required_size; /* Size of len encoding */
- uint8_t *buf = (uint8_t *)bufp;
- uint8_t *end;
- size_t i;
-
- if(len <= 127) {
- /* Encoded in 1 octet */
- if(size) *buf = (uint8_t)len;
- return 1;
- }
-
- /*
- * Compute the size of the subsequent bytes.
- */
- for(required_size = 1, i = 8; i < 8 * sizeof(len); i += 8) {
- if(len >> i)
- required_size++;
- else
- break;
- }
-
- if(size <= required_size)
- return required_size + 1;
-
- *buf++ = (uint8_t)(0x80 | required_size); /* Length of the encoding */
-
- /*
- * Produce the len encoding, space permitting.
- */
- end = buf + required_size;
- for(i -= 8; buf < end; i -= 8, buf++)
- *buf = (uint8_t)(len >> i);
-
- return required_size + 1;
-}
-
git.stg.codes / stg.git / blobdiff