SXE_RETURN
md5_to_hex(SOPHOS_MD5 * md5, char * md5_in_hex, unsigned md5_in_hex_length)
{
SXE_RETURN result = SXE_RETURN_OK;
SXEE86("(md5=%08x%08x%08x%08x,md5_in_hex='%p',md5_in_hex_length='%u'",
md5->word[3], md5->word[2], md5->word[1], md5->word[0],
md5_in_hex, md5_in_hex_length);
SXEA11(md5_in_hex_length == (MD5_IN_HEX_LENGTH + 1), "Incorrect length of char * for md5_to_hex(): '%u'", md5_in_hex_length);
snprintf(md5_in_hex , 9, "%08x", htonl(md5->word[0]));
snprintf(md5_in_hex + 8, 9, "%08x", htonl(md5->word[1]));
snprintf(md5_in_hex + 16, 9, "%08x", htonl(md5->word[2]));
snprintf(md5_in_hex + 24, 9, "%08x", htonl(md5->word[3]));
SXEL62("md5_in_hex: '%.*s'", MD5_IN_HEX_LENGTH, md5_in_hex);
SXER81("return %s", sxe_return_to_string(result));
return result;
}
/* Note that the decoded_name will be NUL terminated, and therefore the
* maximum_name_length_maximum should probably be 254 and not 253 (though, with
* pointers, the decoded name could well be *longer* than 253 characters!
*/
static SXE_RETURN
sxe_dns_decode_name(
const unsigned char * dns_packet ,
unsigned dns_packet_length ,
unsigned name_offset ,
char * decoded_name ,
unsigned decoded_name_length_maximum,
unsigned * decoded_name_length )
{
SXE_RETURN result = SXE_RETURN_ERROR_INTERNAL;
unsigned decoded_name_offset = 0;
SXEE86("sxe_dns_decode_name(dns_packet=%p, dns_packet_length=%u, name_offset=%u, decoded_name=%p, decoded_name_length_maximum=%u, decoded_name_length=%p)", dns_packet, dns_packet_length, name_offset, decoded_name, decoded_name_length_maximum, decoded_name_length);
SXEA10(decoded_name_length != 0, "A value for decoded_name_length must be provided");
SXEA10(decoded_name == NULL || decoded_name_length_maximum != 0, "NAME can not be decoded into an empty buffer");
while (name_offset < dns_packet_length) {
unsigned char len = dns_packet[name_offset];
if (len == '\0') {
SXEL60("NAME is terminated normally");
if (decoded_name_offset > 0) {
--decoded_name_offset;
}
if (decoded_name != NULL) {
decoded_name[decoded_name_offset] = '\0';
}
*decoded_name_length = decoded_name_offset;
result = SXE_RETURN_OK;
goto SXE_EARLY_OUT;
}
else if ((len & SXE_DNS_LABEL_LENGTH_POINTER) == 0) {
SXEL73("Normal label of length %u '%.*s'", len, len, &dns_packet[name_offset + 1]);
/* Don't allow the NAME to exceed the known packet length */
if ((decoded_name != NULL) && (decoded_name_offset + len + 1 >= decoded_name_length_maximum)) {
SXEL51("sxe_dns_decode_name(): NAME is invalid; Decoded NAME is longer than the provided buffer length %u", decoded_name_length_maximum);
goto SXE_ERROR_OUT;
}
/* Copy the label */
if (decoded_name != NULL) {
memcpy((unsigned char*)(decoded_name + decoded_name_offset), dns_packet + name_offset + 1, len);
decoded_name[decoded_name_offset + len] = '.';
}
decoded_name_offset += len + 1;
}
else if ((len & SXE_DNS_LABEL_LENGTH_POINTER) == SXE_DNS_LABEL_LENGTH_POINTER) {
SXEL60("NAME includes a pointer");
name_offset = (len & ~SXE_DNS_LABEL_LENGTH_POINTER) + dns_packet[name_offset + 1];
SXEL61("New NAME offset is %u", name_offset);
/* Prevent looping forever - a pointer should never point to a pointer
*/
if ((dns_packet[name_offset] & SXE_DNS_LABEL_LENGTH_POINTER) != 0) {
SXEL51("sxe_dns_decode_name(): NAME contains a pointer which points to another pointer at packet offset %u",
name_offset);
goto SXE_ERROR_OUT;
}
continue;
}
else {
SXEL51("sxe_dns_decode_name(): NAME is invalid; NAME contains an invalid length/pointer value at packet offset %u", name_offset);
goto SXE_ERROR_OUT;
}
name_offset += len + 1;
}
SXEL60("NAME is invalid because it extends outside the packet");
SXE_ERROR_OUT:
SXE_EARLY_OUT:
SXER81("return // result=%s", sxe_return_to_string(result));
return result;
}
