test: add case for GH opencontainers#2086

Commit 5e0e67d ("fix permission denied") modified some code but
did not provide a test case.

This is a test case that was tested to fail before and succeed after
the above commit.

For more details, see opencontainers#2086

Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>

tests/integration/cwd.bats

@@ -0,0 +1,30 @@
+#!/usr/bin/env bats
+
+load helpers
+
+function setup() {
+	teardown_busybox
+	setup_busybox
+}
+
+function teardown() {
+	teardown_busybox
+}
+
+# Test case for https://github.com/opencontainers/runc/pull/2086
+@test "runc exec --user with no access to cwd" {
+	requires root
+
+	chown 42 rootfs/root
+	chmod 700 rootfs/root
+
+	update_config '	  .process.cwd = "/root"
+			| .process.user.uid = 42
+			| .process.args |= ["sleep", "1h"]'
+
+	runc run -d --console-socket "$CONSOLE_SOCKET" test_busybox
+	[ "$status" -eq 0 ]
+
+	runc exec --user 0 test_busybox true
+	[ "$status" -eq 0 ]
+}