diff options
| -rw-r--r-- | src/libexpr/primops.cc | 29 | ||||
| -rw-r--r-- | tests/pure-eval.sh | 3 |
2 files changed, 25 insertions, 7 deletions
diff --git a/src/libexpr/primops.cc b/src/libexpr/primops.cc index aff8f951e..62c21c7c5 100644 --- a/src/libexpr/primops.cc +++ b/src/libexpr/primops.cc @@ -89,18 +89,28 @@ StringMap EvalState::realiseContext(const PathSet & context) return res; } -static Path realisePath(EvalState & state, const Pos & pos, Value & v, bool requireAbsolutePath = true) +struct RealisePathFlags { + // Whether to check whether the path is a valid absolute path + bool requireAbsolutePath = true; + // Whether to check that the path is allowed in pure eval mode + bool checkForPureEval = true; +}; + +static Path realisePath(EvalState & state, const Pos & pos, Value & v, const RealisePathFlags flags = {}) { PathSet context; - Path path = requireAbsolutePath + Path path = flags.requireAbsolutePath ? state.coerceToPath(pos, v, context) : state.coerceToString(pos, v, context, false, false); StringMap rewrites = state.realiseContext(context); - return state.checkSourcePath( - state.toRealPath(rewriteStrings(path, rewrites), context)); + auto realPath = state.toRealPath(rewriteStrings(path, rewrites), context); + + return flags.checkForPureEval + ? state.checkSourcePath(realPath) + : realPath; } /* Add and attribute to the given attribute map from the output name to @@ -1371,7 +1381,12 @@ static void prim_pathExists(EvalState & state, const Pos & pos, Value * * args, { Path path; try { - path = realisePath(state, pos, *args[0]); + // We don’t check the path right now, because we don’t want to throw if + // the path isn’t allowed, but just return false + // (and we can’t just catch the exception here because we still want to + // throw if something in the evaluation of `*args[0]` tries to access an + // unauthorized path) + path = realisePath(state, pos, *args[0], { .checkForPureEval = false }); } catch (InvalidPathError & e) { throw EvalError({ .msg = hintfmt( @@ -1382,7 +1397,7 @@ static void prim_pathExists(EvalState & state, const Pos & pos, Value * * args, } try { - mkBool(v, pathExists(path)); + mkBool(v, pathExists(state.checkSourcePath(path))); } catch (SysError & e) { /* Don't give away info from errors while canonicalising ‘path’ in restricted mode. */ @@ -1496,7 +1511,7 @@ static void prim_findFile(EvalState & state, const Pos & pos, Value * * args, Va Path path; try { - path = realisePath(state, pos, *i->value, false); + path = realisePath(state, pos, *i->value, { .requireAbsolutePath = false }); } catch (InvalidPathError & e) { throw EvalError({ .msg = hintfmt("cannot find '%1%', since path '%2%' is not valid", path, e.path), diff --git a/tests/pure-eval.sh b/tests/pure-eval.sh index cb4b5c5fc..1a4568ea6 100644 --- a/tests/pure-eval.sh +++ b/tests/pure-eval.sh @@ -11,6 +11,9 @@ missingImpureErrorMsg=$(! nix eval --expr 'builtins.readFile ./pure-eval.sh' 2>& echo "$missingImpureErrorMsg" | grep -q -- --impure || \ fail "The error message should mention the “--impure” flag to unblock users" +[[ $(nix eval --expr 'builtins.pathExists ./pure-eval.sh') == false ]] || \ + fail "Calling 'pathExists' on a non-authorised path should return false" + (! nix eval --expr builtins.currentTime) (! nix eval --expr builtins.currentSystem) |