path fetcher: Fix relative path check

This commit is contained in:
Eelco Dolstra 2021-09-21 13:19:26 +02:00
parent be69a98d2c
commit 5cbb9c5406
2 changed files with 11 additions and 6 deletions

View file

@ -85,18 +85,23 @@ struct PathInputScheme : InputScheme
std::string absPath;
auto path = getStrAttr(input.attrs, "path");
if (path[0] != '/' && input.parent) {
if (path[0] != '/') {
if (!input.parent)
throw Error("cannot fetch input '%s' because it uses a relative path", input.to_string());
auto parent = canonPath(*input.parent);
// the path isn't relative, prefix it
absPath = canonPath(parent + "/" + path);
absPath = nix::absPath(path, parent);
// for security, ensure that if the parent is a store path, it's inside it
if (!parent.rfind(store->storeDir, 0) && absPath.rfind(store->storeDir, 0))
throw BadStorePath("relative path '%s' points outside of its parent's store path %s, this is a security violation", path, parent);
if (store->isInStore(parent) && !isInDir(absPath, parent))
throw BadStorePath("relative path '%s' [%s] points outside of its parent's store path '%s'", path, absPath, parent);
} else
absPath = path;
Activity act(*logger, lvlTalkative, actUnknown, fmt("copying '%s'", absPath));
// FIXME: check whether access to 'path' is allowed.
auto storePath = store->maybeParseStorePath(absPath);

View file

@ -766,7 +766,7 @@ cat > $flakeFollowsA/flake.nix <<EOF
{
description = "Flake A";
inputs = {
B.url = "path:./../../flakeB";
B.url = "path:../flakeB";
};
outputs = { ... }: {};
}
@ -774,7 +774,7 @@ EOF
git -C $flakeFollowsA add flake.nix
nix flake lock $flakeFollowsA 2>&1 | grep 'this is a security violation'
nix flake lock $flakeFollowsA 2>&1 | grep 'points outside'
# Test flake in store does not evaluate
rm -rf $badFlakeDir