Merge pull request #12045 from DeterminateSystems/allow-closure

EvalState::realiseContext(): Allow access to the entire closure
NixOS · Dec 16, 2024 · a24d1c3 · a24d1c3
2 parents 18770c7 + 08361f0
commit a24d1c3
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Showing 5 changed files with 44 additions and 10 deletions.
diff --git a/src/libexpr/eval.cc b/src/libexpr/eval.cc
@@ -347,6 +347,16 @@ void EvalState::allowPath(const StorePath & storePath)
         rootFS2->allowPrefix(CanonPath(store->toRealPath(storePath)));
 }
 
+void EvalState::allowClosure(const StorePath & storePath)
+{
+    if (!rootFS.dynamic_pointer_cast<AllowListSourceAccessor>()) return;
+
+    StorePathSet closure;
+    store->computeFSClosure(storePath, closure);
+    for (auto & p : closure)
+        allowPath(p);
+}
+
 void EvalState::allowAndSetStorePathString(const StorePath & storePath, Value & v)
 {
     allowPath(storePath);
@@ -3099,10 +3109,7 @@ std::optional<SourcePath> EvalState::resolveLookupPathPath(const LookupPath::Pat
             allowPath(path.path.abs());
             if (store->isInStore(path.path.abs())) {
                 try {
-                    StorePathSet closure;
-                    store->computeFSClosure(store->toStorePath(path.path.abs()).first, closure);
-                    for (auto & p : closure)
-                        allowPath(p);
+                    allowClosure(store->toStorePath(path.path.abs()).first);
                 } catch (InvalidPath &) { }
             }
         }

diff --git a/src/libexpr/eval.hh b/src/libexpr/eval.hh
@@ -400,6 +400,11 @@ public:
      */
     void allowPath(const StorePath & storePath);
 
+    /**
+     * Allow access to the closure of a store path.
+     */
+    void allowClosure(const StorePath & storePath);
+
     /**
      * Allow access to a store path and return it as a string.
      */

diff --git a/src/libexpr/primops.cc b/src/libexpr/primops.cc
@@ -119,11 +119,9 @@ StringMap EvalState::realiseContext(const NixStringContext & context, StorePathS
     if (store != buildStore) copyClosure(*buildStore, *store, outputsToCopyAndAllow);
 
     if (isIFD) {
-        for (auto & outputPath : outputsToCopyAndAllow) {
-            /* Add the output of this derivations to the allowed
-            paths. */
-            allowPath(outputPath);
-        }
+        /* Allow access to the output closures of this derivation. */
+        for (auto & outputPath : outputsToCopyAndAllow)
+            allowClosure(outputPath);
     }
 
     return res;

diff --git a/tests/functional/import-from-derivation.nix b/tests/functional/import-from-derivation.nix
@@ -1,4 +1,4 @@
-with import ./config.nix;
+with import <config>;
 
 rec {
   bar = mkDerivation {
@@ -30,4 +30,23 @@ rec {
         echo -n BLA$(cat $src) > $out
       '';
   };
+
+  step1 = mkDerivation {
+    name = "step1";
+    buildCommand = ''
+      mkdir -p $out
+      echo 'foo' > $out/bla
+    '';
+  };
+
+  addPathExpr = mkDerivation {
+    name = "add-path";
+    inherit step1;
+    buildCommand = ''
+      mkdir -p $out
+      echo "builtins.path { path = \"$step1\"; sha256 = \"7ptL+pnrZXnSa5hwwB+2SXTLkcSb5264WGGokN8OXto=\"; }" > $out/default.nix
+    '';
+  };
+
+  importAddPathExpr = import addPathExpr;
 }
diff --git a/tests/functional/import-from-derivation.sh b/tests/functional/import-from-derivation.sh
@@ -6,6 +6,8 @@ TODO_NixOS
 
 clearStoreIfPossible
 
+export NIX_PATH=config="${config_nix}"
+
 if nix-instantiate --readonly-mode ./import-from-derivation.nix -A result; then
     echo "read-only evaluation of an imported derivation unexpectedly failed"
     exit 1
@@ -15,6 +17,9 @@ outPath=$(nix-build ./import-from-derivation.nix -A result --no-out-link)
 
 [ "$(cat "$outPath")" = FOO579 ]
 
+# Check that we can have access to the entire closure of a derivation output.
+nix build --no-link --restrict-eval -I src=. -f ./import-from-derivation.nix importAddPathExpr -v
+
 # FIXME: the next tests are broken on CA.
 if [[ -n "${NIX_TESTS_CA_BY_DEFAULT:-}" ]]; then
     exit 0