1 files changed, 138 insertions, 0 deletions
diff --git a/third_party/nix/src/libstore/crypto.cc b/third_party/nix/src/libstore/crypto.cc
new file mode 100644
index 0000000000..0a2795cb0a
--- /dev/null
+++ b/third_party/nix/src/libstore/crypto.cc
@@ -0,0 +1,138 @@
+#include "libstore/crypto.hh"
+
+#include <absl/strings/escaping.h>
+
+#include "libstore/globals.hh"
+#include "libutil/util.hh"
+
+#if HAVE_SODIUM
+#include <sodium.h>
+#endif
+
+namespace nix {
+
+// TODO(riking): convert to string_view to reduce allocations
+static std::pair<std::string, std::string> split(const std::string& s) {
+  size_t colon = s.find(':');
+  if (colon == std::string::npos || colon == 0) {
+    return {"", ""};
+  }
+  return {std::string(s, 0, colon), std::string(s, colon + 1)};
+}
+
+Key::Key(const std::string& s) {
+  auto ss = split(s);
+
+  name = ss.first;
+  std::string keyb64 = ss.second;
+
+  if (name.empty() || keyb64.empty()) {
+    throw Error("secret key is corrupt");
+  }
+
+  if (!absl::Base64Unescape(keyb64, &key)) {
+    // TODO(grfn): replace this with StatusOr
+    throw Error("Invalid Base64");
+  }
+}
+
+SecretKey::SecretKey(const std::string& s) : Key(s) {
+#if HAVE_SODIUM
+  if (key.size() != crypto_sign_SECRETKEYBYTES) {
+    throw Error("secret key is not valid");
+  }
+#endif
+}
+
+#if !HAVE_SODIUM
+[[noreturn]] static void noSodium() {
+  throw Error(
+      "Nix was not compiled with libsodium, required for signed binary cache "
+      "support");
+}
+#endif
+
+std::string SecretKey::signDetached(const std::string& data) const {
+#if HAVE_SODIUM
+  unsigned char sig[crypto_sign_BYTES];
+  unsigned long long sigLen;
+  crypto_sign_detached(sig, &sigLen, (unsigned char*)data.data(), data.size(),
+                       (unsigned char*)key.data());
+  return name + ":" +
+         absl::Base64Escape(std::string(reinterpret_cast<char*>(sig), sigLen));
+#else
+  noSodium();
+#endif
+}
+
+PublicKey SecretKey::toPublicKey() const {
+#if HAVE_SODIUM
+  unsigned char pk[crypto_sign_PUBLICKEYBYTES];
+  crypto_sign_ed25519_sk_to_pk(pk, (unsigned char*)key.data());
+  return PublicKey(name, std::string(reinterpret_cast<char*>(pk),
+                                     crypto_sign_PUBLICKEYBYTES));
+#else
+  noSodium();
+#endif
+}
+
+PublicKey::PublicKey(const std::string& s) : Key(s) {
+#if HAVE_SODIUM
+  if (key.size() != crypto_sign_PUBLICKEYBYTES) {
+    throw Error("public key is not valid");
+  }
+#endif
+}
+
+bool verifyDetached(const std::string& data, const std::string& sig,
+                    const PublicKeys& publicKeys) {
+#if HAVE_SODIUM
+  auto ss = split(sig);
+
+  auto key = publicKeys.find(ss.first);
+  if (key == publicKeys.end()) {
+    return false;
+  }
+
+  std::string sig2;
+  if (!absl::Base64Unescape(ss.second, &sig2)) {
+    // TODO(grfn): replace this with StatusOr
+    throw Error("Invalid Base64");
+  }
+  if (sig2.size() != crypto_sign_BYTES) {
+    throw Error("signature is not valid");
+  }
+
+  return crypto_sign_verify_detached(
+             reinterpret_cast<unsigned char*>(sig2.data()),
+             (unsigned char*)data.data(), data.size(),
+             (unsigned char*)key->second.key.data()) == 0;
+#else
+  noSodium();
+#endif
+}
+
+PublicKeys getDefaultPublicKeys() {
+  PublicKeys publicKeys;
+
+  // FIXME: filter duplicates
+
+  for (const auto& s : settings.trustedPublicKeys.get()) {
+    PublicKey key(s);
+    publicKeys.emplace(key.name, key);
+  }
+
+  for (const auto& secretKeyFile : settings.secretKeyFiles.get()) {
+    try {
+      SecretKey secretKey(readFile(secretKeyFile));
+      publicKeys.emplace(secretKey.name, secretKey.toPublicKey());
+    } catch (SysError& e) {
+      /* Ignore unreadable key files. That's normal in a
+         multi-user installation. */
+    }
+  }
+
+  return publicKeys;
+}
+
+}  // namespace nix