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Factor out checksum checking from descriptor parsing

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This commit is contained in:
Pieter Wuille 2019-05-08 14:01:35 -07:00
parent e5fdda68c6
commit 104b3a5069
1 changed files with 20 additions and 13 deletions
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33
src/script/descriptor.cpp
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@ -910,22 +910,29 @@ std::unique_ptr<DescriptorImpl> InferScript(const CScript& script, ParseScriptCo
} // namespace } // namespace
/** Check a descriptor checksum, and update desc to be the checksum-less part. */
bool CheckChecksum(Span<const char>& sp, bool require_checksum, std::string* out_checksum = nullptr)
{
auto check_split = Split(sp, '#');
if (check_split.size() > 2) return false; // Multiple '#' symbols
if (check_split.size() == 1 && require_checksum) return false; // Missing checksum
if (check_split.size() == 2) {
if (check_split[1].size() != 8) return false; // Unexpected length for checksum
}
auto checksum = DescriptorChecksum(check_split[0]);
if (checksum.empty()) return false; // Invalid characters in payload
if (check_split.size() == 2) {
if (!std::equal(checksum.begin(), checksum.end(), check_split[1].begin())) return false; // Checksum mismatch
}
if (out_checksum) *out_checksum = std::move(checksum);
sp = check_split[0];
return true;
}
std::unique_ptr<Descriptor> Parse(const std::string& descriptor, FlatSigningProvider& out, bool require_checksum) std::unique_ptr<Descriptor> Parse(const std::string& descriptor, FlatSigningProvider& out, bool require_checksum)
{ {
Span<const char> sp(descriptor.data(), descriptor.size()); Span<const char> sp(descriptor.data(), descriptor.size());
if (!CheckChecksum(sp, require_checksum)) return nullptr;
// Checksum checks
auto check_split = Split(sp, '#');
if (check_split.size() > 2) return nullptr; // Multiple '#' symbols
if (check_split.size() == 1 && require_checksum) return nullptr; // Missing checksum
if (check_split.size() == 2) {
if (check_split[1].size() != 8) return nullptr; // Unexpected length for checksum
auto checksum = DescriptorChecksum(check_split[0]);
if (checksum.empty()) return nullptr; // Invalid characters in payload
if (!std::equal(checksum.begin(), checksum.end(), check_split[1].begin())) return nullptr; // Checksum mismatch
}
sp = check_split[0];
auto ret = ParseScript(sp, ParseScriptContext::TOP, out); auto ret = ParseScript(sp, ParseScriptContext::TOP, out);
if (sp.size() == 0 && ret) return std::unique_ptr<Descriptor>(std::move(ret)); if (sp.size() == 0 && ret) return std::unique_ptr<Descriptor>(std::move(ret));
return nullptr; return nullptr;