From 5eb22de16d8fee5b1bb2f1a3db77711707240b22 Mon Sep 17 00:00:00 2001
From: Archit Dewan <108434204+ArchitDewan@users.noreply.github.com>
Date: Sun, 11 Oct 2026 20:28:56 -0400
Subject: [PATCH] fix(relinker): reject empty positional paths

---
 core/relinker/cli/src/CliArgs.cpp        | 2 ++
 core/relinker/cli/tests/CliArgsTests.cpp | 8 ++++++++
 2 files changed, 10 insertions(+)

diff --git a/core/relinker/cli/src/CliArgs.cpp b/core/relinker/cli/src/CliArgs.cpp
index eef10daad..21d055d6b 100644
--- a/core/relinker/cli/src/CliArgs.cpp
+++ b/core/relinker/cli/src/CliArgs.cpp
@@ -71,6 +71,8 @@ Args ParseArgs(int argc, char* argv[]) {
             args.windowsGui = true;
         } else if (arg.rfind("--", 0) == 0 || arg == "unused-filter") {
             throw std::runtime_error("unknown option: " + arg);
+        } else if (arg.empty()) {
+            throw std::runtime_error("input and output paths must be nonempty");
         } else if (args.inputPath.empty()) {
             args.inputPath = arg;
         } else if (args.outputPath.empty()) {
diff --git a/core/relinker/cli/tests/CliArgsTests.cpp b/core/relinker/cli/tests/CliArgsTests.cpp
index ec27e771a..3cc339e55 100644
--- a/core/relinker/cli/tests/CliArgsTests.cpp
+++ b/core/relinker/cli/tests/CliArgsTests.cpp
@@ -163,6 +163,13 @@ void unknownOption() {
     expectThrows({"--", "input.elf", "output.elf"}, "unknown option: --");
 }
 
+void emptyPositionals() {
+    for (const auto& arguments : std::vector<std::vector<std::string>>{
+            {"", "input.elf", "output.elf"}, {"input.elf", "", "output.elf"},
+            {"", "output.elf"}, {"input.elf", ""}})
+        expectThrows(arguments, "input and output paths must be nonempty");
+}
+
 void tooManyPositionals() {
     expectThrows({"input.elf", "output.elf", "extra.elf"}, "unexpected argument: extra.elf");
 }
@@ -211,6 +218,7 @@ int main() {
         unusedFilterRejectsDuplicates();
         unusedFilterBareWordIsUnknown();
         unknownOption();
+        emptyPositionals();
         tooManyPositionals();
         windowsDiagnosticsRequiresWindows();
         windowsGuiRequiresWindows();