3rd-party/libtins
1
0
Fork 0
mirror of https://github.com/mfontanini/libtins synced 2026-01-22 18:25:57 +01:00
Code Issues Releases Wiki Activity

Fix pointer loop bug and add descriptive exceptions

Browse Source
This commit is contained in:
Gaya Cohen
2021-05-24 15:12:23 +03:00
parent 5858132261
commit c20c82bcb5
2 changed files with 18 additions and 1 deletions
Download Patch File Download Diff File Expand all files Collapse all files

13
include/tins/exceptions.h
View File

@@ -66,6 +66,19 @@ public:
malformed_packet() : exception_base("Malformed packet") { }
};
class DNS_decompression_pointer_out_of_bounds : public exception_base {
public:
DNS_decompression_pointer_out_of_bounds() : exception_base("DNS decompression pointer out of bounds") { }
};
/**
* \brief Exception thrown when a DNS decompression pointer loops.
*/
class DNS_decompression_pointer_loops : public exception_base {
public:
DNS_decompression_pointer_loops() : exception_base("DNS decompression pointer loops") { }
};
/**
* \brief Exception thrown when serializing a packet fails.
*/

6
src/dns.cpp
View File

@@ -336,7 +336,11 @@ uint32_t DNS::compose_name(const uint8_t* ptr, char* out_ptr) const {
const uint8_t* end = &records_data_[0] + records_data_.size();
const uint8_t* end_ptr = 0;
char* current_out_ptr = out_ptr;
int pointer_counter = 0;
while (*ptr) {
if (pointer_counter++ > 30){
throw DNS_decompression_pointer_loops();
}
// It's an offset
if ((*ptr & 0xc0)) {
if (TINS_UNLIKELY(ptr + sizeof(uint16_t) > end)) {
@@ -347,7 +351,7 @@ uint32_t DNS::compose_name(const uint8_t* ptr, char* out_ptr) const {
index = Endian::be_to_host(index) & 0x3fff;
// Check that the offset is neither too low or too high
if (index < 0x0c || (&records_data_[0] + (index - 0x0c)) >= end) {
throw malformed_packet();
throw DNS_decompression_pointer_out_of_bounds();
}
// We've probably found the end of the original domain name. Save it.
if (end_ptr == 0) {