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Merge #18023: Fix some asmap issues

Browse Source 
c86bc14408 Make asmap Interpret tolerant of malicious map data (Pieter Wuille)
38c2395d7a Use ASNs for mapped IPv4 addresses correctly (Pieter Wuille)
6f8c937312 Mark asmap const in statistics code (Pieter Wuille)
d58bcdc4b5 Avoid asmap copies in initialization (Pieter Wuille)

Pull request description:

  Here are a few things to improve in the asmap implementation. The first two commits are just code improvements. The last one is a bugfix (the exsting code wouldn't correctly apply ASN lookups to mapped/embedded IPv4 addresses).

ACKs for top commit:
  practicalswift:
    ACK c86bc14408 -- patch looks correct
  naumenkogs:
    utACK c86bc14
  laanwj:
    ACK c86bc14408
  jonatack:
    ACK c86bc14408 code looks correct, built/ran tests, bitcoind with -asmap pointed to asmap/demo.map

Tree-SHA512: 1036f43152754d621bfbecfd3b7c7276e4670598fcaed42a3d275e51fa2cf3653e2c9e9cfa714f6c7719362541510e92171e076ac4169b55a0cc8908b2d514c0
This commit is contained in:
Wladimir J. van der Laan
2020-02-05 13:36:13 +01:00
parent bd5c4c6971 c86bc14408
commit adea5e1b54
6 changed files with 89 additions and 63 deletions
Download Patch File Download Diff File Expand all files Collapse all files

42
src/util/asmap.cpp
View File

@@ -8,13 +8,14 @@
namespace {
uint32_t DecodeBits(std::vector<bool>::const_iterator& bitpos, uint8_t minval, const std::vector<uint8_t> &bit_sizes)
uint32_t DecodeBits(std::vector<bool>::const_iterator& bitpos, const std::vector<bool>::const_iterator& endpos, uint8_t minval, const std::vector<uint8_t> &bit_sizes)
{
uint32_t val = minval;
bool bit;
for (std::vector<uint8_t>::const_iterator bit_sizes_it = bit_sizes.begin();
bit_sizes_it != bit_sizes.end(); ++bit_sizes_it) {
if (bit_sizes_it + 1 != bit_sizes.end()) {
if (bitpos == endpos) break;
bit = *bitpos;
bitpos++;
} else {
@@ -24,6 +25,7 @@ uint32_t DecodeBits(std::vector<bool>::const_iterator& bitpos, uint8_t minval, c
val += (1 << *bit_sizes_it);
} else {
for (int b = 0; b < *bit_sizes_it; b++) {
if (bitpos == endpos) break;
bit = *bitpos;
bitpos++;
val += bit << (*bit_sizes_it - 1 - b);
@@ -35,29 +37,29 @@ uint32_t DecodeBits(std::vector<bool>::const_iterator& bitpos, uint8_t minval, c
}
const std::vector<uint8_t> TYPE_BIT_SIZES{0, 0, 1};
uint32_t DecodeType(std::vector<bool>::const_iterator& bitpos)
uint32_t DecodeType(std::vector<bool>::const_iterator& bitpos, const std::vector<bool>::const_iterator& endpos)
{
return DecodeBits(bitpos, 0, TYPE_BIT_SIZES);
return DecodeBits(bitpos, endpos, 0, TYPE_BIT_SIZES);
}
const std::vector<uint8_t> ASN_BIT_SIZES{15, 16, 17, 18, 19, 20, 21, 22, 23, 24};
uint32_t DecodeASN(std::vector<bool>::const_iterator& bitpos)
uint32_t DecodeASN(std::vector<bool>::const_iterator& bitpos, const std::vector<bool>::const_iterator& endpos)
{
return DecodeBits(bitpos, 1, ASN_BIT_SIZES);
return DecodeBits(bitpos, endpos, 1, ASN_BIT_SIZES);
}
const std::vector<uint8_t> MATCH_BIT_SIZES{1, 2, 3, 4, 5, 6, 7, 8};
uint32_t DecodeMatch(std::vector<bool>::const_iterator& bitpos)
uint32_t DecodeMatch(std::vector<bool>::const_iterator& bitpos, const std::vector<bool>::const_iterator& endpos)
{
return DecodeBits(bitpos, 2, MATCH_BIT_SIZES);
return DecodeBits(bitpos, endpos, 2, MATCH_BIT_SIZES);
}
const std::vector<uint8_t> JUMP_BIT_SIZES{5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30};
uint32_t DecodeJump(std::vector<bool>::const_iterator& bitpos)
uint32_t DecodeJump(std::vector<bool>::const_iterator& bitpos, const std::vector<bool>::const_iterator& endpos)
{
return DecodeBits(bitpos, 17, JUMP_BIT_SIZES);
return DecodeBits(bitpos, endpos, 17, JUMP_BIT_SIZES);
}
}
@@ -65,33 +67,37 @@ uint32_t DecodeJump(std::vector<bool>::const_iterator& bitpos)
uint32_t Interpret(const std::vector<bool> &asmap, const std::vector<bool> &ip)
{
std::vector<bool>::const_iterator pos = asmap.begin();
const std::vector<bool>::const_iterator endpos = asmap.end();
uint8_t bits = ip.size();
uint8_t default_asn = 0;
uint32_t default_asn = 0;
uint32_t opcode, jump, match, matchlen;
while (1) {
assert(pos != asmap.end());
opcode = DecodeType(pos);
while (pos != endpos) {
opcode = DecodeType(pos, endpos);
if (opcode == 0) {
return DecodeASN(pos);
return DecodeASN(pos, endpos);
} else if (opcode == 1) {
jump = DecodeJump(pos);
jump = DecodeJump(pos, endpos);
if (bits == 0) break;
if (ip[ip.size() - bits]) {
if (jump >= endpos - pos) break;
pos += jump;
}
bits--;
} else if (opcode == 2) {
match = DecodeMatch(pos);
match = DecodeMatch(pos, endpos);
matchlen = CountBits(match) - 1;
for (uint32_t bit = 0; bit < matchlen; bit++) {
if (bits == 0) break;
if ((ip[ip.size() - bits]) != ((match >> (matchlen - 1 - bit)) & 1)) {
return default_asn;
}
bits--;
}
} else if (opcode == 3) {
default_asn = DecodeASN(pos);
default_asn = DecodeASN(pos, endpos);
} else {
assert(0);
break;
}
}
return 0; // 0 is not a valid ASN
}