nixbld: re-add networked derivations patch

nixbld-etc-nixos/configuration.nix

@@ -497,6 +497,9 @@ in
   };
  
   nixpkgs.config.packageOverrides = super: let self = super.pkgs; in {
+    nix = super.nix.overrideAttrs(oa: {
+      patches = oa.patches or [] ++ [ ./nix-28-networked-derivations.patch ];
+    });
     hydra_unstable = super.hydra_unstable.overrideAttrs(oa: {
       patches = oa.patches or [] ++ [
         ./hydra-conda.patch

nixbld-etc-nixos/nix-28-networked-derivations.patch

@@ -0,0 +1,80 @@
+diff --git a/src/libstore/build/local-derivation-goal.cc b/src/libstore/build/local-derivation-goal.cc
+index 4c91fa4fb..e2139d6c6 100644
+--- a/src/libstore/build/local-derivation-goal.cc
++++ b/src/libstore/build/local-derivation-goal.cc
+@@ -378,6 +378,8 @@ void LocalDerivationGoal::startBuilder()
+     additionalSandboxProfile = parsedDrv->getStringAttr("__sandboxProfile").value_or("");
+ #endif
+ 
++    networked = parsedDrv->getBoolAttr("__networked");
++
+     /* Are we doing a chroot build? */
+     {
+         auto noChroot = parsedDrv->getBoolAttr("__noChroot");
+@@ -395,7 +397,7 @@ void LocalDerivationGoal::startBuilder()
+         else if (settings.sandboxMode == smDisabled)
+             useChroot = false;
+         else if (settings.sandboxMode == smRelaxed)
+-            useChroot = derivationType.isSandboxed() && !noChroot;
++            useChroot = !networked && derivationType.isSandboxed() && !noChroot;
+     }
+ 
+     auto & localStore = getLocalStore();
+@@ -608,7 +610,7 @@ void LocalDerivationGoal::startBuilder()
+                 "nogroup:x:65534:\n", sandboxGid()));
+ 
+         /* Create /etc/hosts with localhost entry. */
+-        if (derivationType.isSandboxed())
++        if (!networked && derivationType.isSandboxed())
+             writeFile(chrootRootDir + "/etc/hosts", "127.0.0.1 localhost\n::1 localhost\n");
+ 
+         /* Make the closure of the inputs available in the chroot,
+@@ -799,7 +801,7 @@ void LocalDerivationGoal::startBuilder()
+            us.
+         */
+ 
+-        if (derivationType.isSandboxed())
++        if (!networked && derivationType.isSandboxed())
+             privateNetwork = true;
+ 
+         userNamespaceSync.create();
+@@ -1063,7 +1065,7 @@ void LocalDerivationGoal::initEnv()
+        to the builder is generally impure, but the output of
+        fixed-output derivations is by definition pure (since we
+        already know the cryptographic hash of the output). */
+-    if (!derivationType.isSandboxed()) {
++    if (networked || !derivationType.isSandboxed()) {
+         for (auto & i : parsedDrv->getStringsAttr("impureEnvVars").value_or(Strings()))
+             env[i] = getEnv(i).value_or("");
+     }
+@@ -1677,7 +1679,7 @@ void LocalDerivationGoal::runChild()
+             /* Fixed-output derivations typically need to access the
+                network, so give them access to /etc/resolv.conf and so
+                on. */
+-            if (!derivationType.isSandboxed()) {
++            if (networked || !derivationType.isSandboxed()) {
+                 // Only use nss functions to resolve hosts and
+                 // services. Don’t use it for anything else that may
+                 // be configured for this system. This limits the
+@@ -1921,7 +1923,7 @@ void LocalDerivationGoal::runChild()
+ 
+                 sandboxProfile += "(import \"sandbox-defaults.sb\")\n";
+ 
+-                if (!derivationType.isSandboxed())
++                if (networked || !derivationType.isSandboxed())
+                     sandboxProfile += "(import \"sandbox-network.sb\")\n";
+ 
+                 /* Add the output paths we'll use at build-time to the chroot */
+diff --git a/src/libstore/build/local-derivation-goal.hh b/src/libstore/build/local-derivation-goal.hh
+index d456e9cae..0b43a6bd4 100644
+--- a/src/libstore/build/local-derivation-goal.hh
++++ b/src/libstore/build/local-derivation-goal.hh
+@@ -41,6 +41,8 @@ struct LocalDerivationGoal : public DerivationGoal
+ 
+     Path chrootRootDir;
+ 
++    bool networked;
++
+     /* RAII object to delete the chroot directory. */
+     std::shared_ptr<AutoDelete> autoDelChroot;
+