From d2b86473a267c960a1f0c012a983176e5d962187 Mon Sep 17 00:00:00 2001 From: Nsable-sh Date: Thu, 13 Aug 2026 11:11:59 -0300 Subject: net: add signed direct onion peer endpoints --- src/btfaddr.cpp | 102 ++++++++++++++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 95 insertions(+), 7 deletions(-) (limited to 'src/btfaddr.cpp') diff --git a/src/btfaddr.cpp b/src/btfaddr.cpp index 6edcc91..ce2ac86 100644 --- a/src/btfaddr.cpp +++ b/src/btfaddr.cpp @@ -19,6 +19,8 @@ #include #include #include +#include +#include using json = nlohmann::json; @@ -166,10 +168,47 @@ static bool HexDecode(const std::string& s, unsigned char* out, size_t n) return true; } +bool NormalizeOnionEndpoint(const std::string& in, std::string& out) +{ + out.clear(); + std::string s = ToLowerTrim(in); + size_t colon = s.rfind(':'); + if (colon == std::string::npos || colon == 0 || colon + 1 >= s.size()) + return false; + + std::string host = s.substr(0, colon); + std::string port = s.substr(colon + 1); + while (!host.empty() && host.back() == '.') host.pop_back(); + static const char* suffix = ".onion"; + const size_t suffixLen = strlen(suffix); + if (host.size() != 56 + suffixLen) + return false; + if (host.compare(host.size() - suffixLen, suffixLen, suffix) != 0) + return false; + for (size_t i = 0; i < 56; i++) + { + char c = host[i]; + if (!((c >= 'a' && c <= 'z') || (c >= '2' && c <= '7'))) + return false; + } + for (size_t i = 0; i < port.size(); i++) + if (!isdigit((unsigned char)port[i])) + return false; + + errno = 0; + char* end = NULL; + long nPort = strtol(port.c_str(), &end, 10); + if (errno == ERANGE || end == NULL || *end != '\0' || nPort <= 0 || nPort > 65535) + return false; + + out = host + ":" + port; + return true; +} + // Digest signed over the descriptor fields (domain-separated). -static void DescriptorDigest(const unsigned char pubkey[32], const std::string& enc, - const std::string& meeting_node, uint64_t created, - unsigned char out[32]) +static void DescriptorDigestV2(const unsigned char pubkey[32], const std::string& enc, + const std::string& meeting_node, uint64_t created, + unsigned char out[32]) { static const char* DS = ".btf-descriptor-v2"; SHA256_CTX ctx; @@ -184,9 +223,27 @@ static void DescriptorDigest(const unsigned char pubkey[32], const std::string& SHA256_Final(out, &ctx); } +static void DescriptorDigestV3(const unsigned char pubkey[32], const std::string& enc, + const std::string& meeting_node, const std::string& onion, + uint64_t created, unsigned char out[32]) +{ + static const char* DS = ".btf-descriptor-v3-onion"; + SHA256_CTX ctx; + SHA256_Init(&ctx); + SHA256_Update(&ctx, (const unsigned char*)DS, strlen(DS)); + SHA256_Update(&ctx, pubkey, 32); + SHA256_Update(&ctx, (const unsigned char*)enc.data(), enc.size()); + SHA256_Update(&ctx, (const unsigned char*)meeting_node.data(), meeting_node.size()); + SHA256_Update(&ctx, (const unsigned char*)onion.data(), onion.size()); + unsigned char be[8]; + for (int i = 0; i < 8; i++) be[i] = (unsigned char)((created >> (8 * (7 - i))) & 0xff); + SHA256_Update(&ctx, be, 8); + SHA256_Final(out, &ctx); +} + std::string SignDescriptor(void* ctxv, const unsigned char seckey[32], const std::string& enc, const std::string& meeting_node, - uint64_t created) + uint64_t created, const std::string& onion) { secp256k1_context* ctx = (secp256k1_context*)ctxv; secp256k1_keypair kp; @@ -197,17 +254,28 @@ std::string SignDescriptor(void* ctxv, const unsigned char seckey[32], secp256k1_xonly_pubkey_serialize(ctx, pubkey, &xpub); unsigned char digest[32]; - DescriptorDigest(pubkey, enc, meeting_node, created, digest); + DescriptorDigestV2(pubkey, enc, meeting_node, created, digest); unsigned char sig[64]; // Deterministic signature (NULL aux_rand), matching Itzal's no-aux-rand signing. if (!secp256k1_schnorrsig_sign32(ctx, sig, digest, &kp, NULL)) return std::string(); json v = json::object(); - v["v"] = 2; + v["v"] = onion.empty() ? 2 : 3; v["pubkey"] = HexEncode(pubkey, 32); v["enc"] = enc; v["meeting_node"] = meeting_node; + if (!onion.empty()) + { + std::string onionNorm; + if (!NormalizeOnionEndpoint(onion, onionNorm)) return std::string(); + unsigned char digest3[32]; + DescriptorDigestV3(pubkey, enc, meeting_node, onionNorm, created, digest3); + unsigned char sig3[64]; + if (!secp256k1_schnorrsig_sign32(ctx, sig3, digest3, &kp, NULL)) return std::string(); + v["onion"] = onionNorm; + v["sig3"] = HexEncode(sig3, 64); + } v["created"] = created; v["sig"] = HexEncode(sig, 64); return v.dump(); @@ -242,15 +310,35 @@ bool VerifyDescriptor(void* ctxv, const std::string& jsonStr, if (!HexDecode(v["sig"].get(), sig, 64)) return false; unsigned char digest[32]; - DescriptorDigest(expect_pubkey, enc, meeting_node, created, digest); + DescriptorDigestV2(expect_pubkey, enc, meeting_node, created, digest); secp256k1_xonly_pubkey xpub; if (!secp256k1_xonly_pubkey_parse(ctx, &xpub, expect_pubkey)) return false; if (!secp256k1_schnorrsig_verify(ctx, sig, digest, 32, &xpub)) return false; + std::string onion; + if (v.contains("onion")) + { + if (v["onion"].is_string() && v.contains("sig3") && v["sig3"].is_string()) + { + std::string onionNorm; + std::string onionRaw = v["onion"].get(); + if (NormalizeOnionEndpoint(onionRaw, onionNorm) && onionNorm == onionRaw) + { + unsigned char sig3[64]; + unsigned char digest3[32]; + DescriptorDigestV3(expect_pubkey, enc, meeting_node, onionNorm, created, digest3); + if (HexDecode(v["sig3"].get(), sig3, 64) && + secp256k1_schnorrsig_verify(ctx, sig3, digest3, 32, &xpub)) + onion = onionNorm; + } + } + } + memcpy(out.pubkey, expect_pubkey, 32); out.enc = enc; out.meeting_node = meeting_node; + out.onion = onion; out.created = created; return true; } -- cgit v1.2.3