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

diff --git a/src/libstore/build/local-derivation-goal.cc b/src/libstore/build/local-derivation-goal.cc
index 61ee5d7aa..f38684973 100644
--- a/src/libstore/build/local-derivation-goal.cc
+++ b/src/libstore/build/local-derivation-goal.cc
@@ -176,6 +176,8 @@ void LocalDerivationGoal::tryLocalBuild() {
         return;
     }
 
+    networked = parsedDrv->getBoolAttr("__networked");
+
     /* Are we doing a chroot build? */
     {
         auto noChroot = parsedDrv->getBoolAttr("__noChroot");
@@ -193,7 +195,7 @@ void LocalDerivationGoal::tryLocalBuild() {
         else if (settings.sandboxMode == smDisabled)
             useChroot = false;
         else if (settings.sandboxMode == smRelaxed)
-            useChroot = derivationType.isSandboxed() && !noChroot;
+            useChroot = !networked && derivationType.isSandboxed() && !noChroot;
     }
 
     auto & localStore = getLocalStore();
@@ -677,7 +679,7 @@ 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,
@@ -884,7 +886,7 @@ void LocalDerivationGoal::startBuilder()
            us.
         */
 
-        if (derivationType.isSandboxed())
+        if (!networked && derivationType.isSandboxed())
             privateNetwork = true;
 
         userNamespaceSync.create();
@@ -1179,7 +1181,7 @@ 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("");
     }
@@ -1811,7 +1813,7 @@ 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
@@ -2059,7 +2061,7 @@ void LocalDerivationGoal::runChild()
                     #include "sandbox-defaults.sb"
                     ;
 
-                if (!derivationType.isSandboxed())
+                if (networked || !derivationType.isSandboxed())
                     sandboxProfile +=
                         #include "sandbox-network.sb"
                         ;
diff --git a/src/libstore/build/local-derivation-goal.hh b/src/libstore/build/local-derivation-goal.hh
index 34c4e9187..c4c26fd6f 100644
--- a/src/libstore/build/local-derivation-goal.hh
+++ b/src/libstore/build/local-derivation-goal.hh
@@ -44,6 +44,8 @@ struct LocalDerivationGoal : public DerivationGoal
 
     Path chrootRootDir;
 
+    bool networked;
+
     /* RAII object to delete the chroot directory. */
     std::shared_ptr<AutoDelete> autoDelChroot;