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getDefaultNixPath: actually respect {restrict,pure}-eval

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Previously, getDefaultNixPath was called too early: at initialisation
time, before CLI and config have been processed, when `restrictEval` and
`pureEval` both have their default value `false`. Call it when
initialising the EvalState instead, and use `setDefault`.
This commit is contained in:
Naïm Favier 2023-01-25 15:10:35 +01:00
parent f233fd496d
commit 1cba5984a6
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GPG key ID: 95AFCE8211908325
4 changed files with 31 additions and 17 deletions
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30
src/libexpr/eval.cc
View file

@ -519,6 +519,7 @@ EvalState::EvalState(
static_assert(sizeof(Env) <= 16, "environment must be <= 16 bytes");
/* Initialise the Nix expression search path. */
evalSettings.nixPath.setDefault(evalSettings.getDefaultNixPath());
if (!evalSettings.pureEval) {
for (auto & i : _searchPath) addToSearchPath(i);
for (auto & i : evalSettings.nixPath.get()) addToSearchPath(i);
@ -2472,30 +2473,35 @@ std::ostream & operator << (std::ostream & str, const ExternalValueBase & v) {
EvalSettings::EvalSettings()
{
auto var = getEnv("NIX_PATH");
if (var) nixPath = parseNixPath(*var);
}
/* impure => NIX_PATH or a default path
* restrict-eval => NIX_PATH
* pure-eval => empty
*/
Strings EvalSettings::getDefaultNixPath()
{
Strings res;
auto add = [&](const Path & p, const std::string & s = std::string()) {
if (pathExists(p)) {
if (s.empty()) {
res.push_back(p);
if (pureEval)
return {};
auto var = getEnv("NIX_PATH");
if (var) {
return parseNixPath(*var);
} else if (restrictEval) {
return {};
} else {
res.push_back(s + "=" + p);
}
}
Strings res;
auto add = [&](const Path & p, const std::optional<std::string> & s = std::nullopt) {
if (pathExists(p))
res.push_back(s ? *s + "=" + p : p);
};
if (!evalSettings.restrictEval && !evalSettings.pureEval) {
add(getHome() + "/.nix-defexpr/channels");
add(settings.nixStateDir + "/profiles/per-user/root/channels/nixpkgs", "nixpkgs");
add(settings.nixStateDir + "/profiles/per-user/root/channels");
}
return res;
}
}
bool EvalSettings::isPseudoUrl(std::string_view s)

4
src/libexpr/eval.hh
View file

@ -570,7 +570,7 @@ struct EvalSettings : Config
{
EvalSettings();
static Strings getDefaultNixPath();
Strings getDefaultNixPath();
static bool isPseudoUrl(std::string_view s);
@ -580,7 +580,7 @@ struct EvalSettings : Config
"Whether builtin functions that allow executing native code should be enabled."};
Setting<Strings> nixPath{
this, getDefaultNixPath(), "nix-path",
this, {}, "nix-path",
"List of directories to be searched for `<...>` file references."};
Setting<bool> restrictEval{

5
tests/nix_path.sh
View file

@ -12,3 +12,8 @@ nix-instantiate --eval -E '<by-relative-path/simple.nix>' --restrict-eval
[[ $(nix-instantiate --find-file by-absolute-path/simple.nix) = $PWD/simple.nix ]]
[[ $(nix-instantiate --find-file by-relative-path/simple.nix) = $PWD/simple.nix ]]
unset NIX_PATH
[[ $(nix-instantiate --option nix-path by-relative-path=. --find-file by-relative-path/simple.nix) = "$PWD/simple.nix" ]]
[[ $(NIX_PATH= nix-instantiate --option nix-path by-relative-path=. --find-file by-relative-path/simple.nix) = "$PWD/simple.nix" ]]

3
tests/restricted.sh
View file

@ -17,6 +17,9 @@ nix-instantiate --restrict-eval --eval -E 'builtins.readDir ../src/nix-channel'
(! nix-instantiate --restrict-eval --eval -E 'let __nixPath = [ { prefix = "foo"; path = ./.; } ]; in <foo>')
nix-instantiate --restrict-eval --eval -E 'let __nixPath = [ { prefix = "foo"; path = ./.; } ]; in <foo>' -I src=.
# no default NIX_PATH
(unset NIX_PATH; ! nix-instantiate --restrict-eval --find-file .)
p=$(nix eval --raw --expr "builtins.fetchurl file://$(pwd)/restricted.sh" --impure --restrict-eval --allowed-uris "file://$(pwd)")
cmp $p restricted.sh