wasm: Propagate leb128 errors when parsing modules

robinlinden · Oct 31, 2023 · a767e37 · a767e37
1 parent a7fd50d
commit a767e37
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Showing 3 changed files with 12 additions and 4 deletions.
diff --git a/wasm/wasm.cpp b/wasm/wasm.cpp
@@ -253,10 +253,12 @@ tl::expected<Module, ModuleParseError> Module::parse_from(std::istream &is) {
             return tl::unexpected{ModuleParseError::InvalidSectionId};
         }
 
-        // TODO(robinlinden): Propagate error from leb128-parsing.
         auto size = Leb128<std::uint32_t>::decode_from(is);
         if (!size) {
-            return tl::unexpected{ModuleParseError::Unknown};
+            if (size.error() == Leb128ParseError::UnexpectedEof) {
+                return tl::unexpected{ModuleParseError::UnexpectedEof};
+            }
+            return tl::unexpected{ModuleParseError::InvalidSize};
         }
 
         std::vector<std::uint8_t> content;

diff --git a/wasm/wasm.h b/wasm/wasm.h
@@ -130,11 +130,11 @@ struct CodeSection {
 };
 
 enum class ModuleParseError {
-    Unknown,
     UnexpectedEof,
     InvalidMagic,
     UnsupportedVersion,
     InvalidSectionId,
+    InvalidSize,
 };
 
 // https://webassembly.github.io/spec/core/syntax/modules.html

diff --git a/wasm/wasm_test.cpp b/wasm/wasm_test.cpp
@@ -395,7 +395,13 @@ int main() {
 
     etest::test("missing size", [] {
         auto wasm_bytes = std::stringstream{"\0asm\1\0\0\0\0"s};
-        expect_eq(wasm::Module::parse_from(std::move(wasm_bytes)), tl::unexpected{wasm::ModuleParseError::Unknown});
+        expect_eq(
+                wasm::Module::parse_from(std::move(wasm_bytes)), tl::unexpected{wasm::ModuleParseError::UnexpectedEof});
+    });
+
+    etest::test("invalid size", [] {
+        auto wasm_bytes = std::stringstream{"\0asm\1\0\0\0\0\x80\x80\x80\x80\x80\x80"s};
+        expect_eq(wasm::Module::parse_from(std::move(wasm_bytes)), tl::unexpected{wasm::ModuleParseError::InvalidSize});
     });
 
     etest::test("missing content", [] {