Parcourir la source

LibWasm: Adjust signed integer operations to avoid UB

Perform signed integer shifts, addition, subtraction, and rotations
using their corresponding unsigned type. Additionally, mod the right
hand side of shifts and rotations by the bit width of the integer per
the spec. This seems strange, but the spec is clear on the desired
wrapping behavior of arithmetic operations.
Andrew Kaster il y a 4 ans
Parent
commit
2af591267c
1 fichiers modifiés avec 17 ajouts et 16 suppressions
  1. 17 16
      Userland/Libraries/LibWasm/AbstractMachine/BytecodeInterpreter.cpp

+ 17 - 16
Userland/Libraries/LibWasm/AbstractMachine/BytecodeInterpreter.cpp

@@ -216,6 +216,7 @@ void BytecodeInterpreter::call_address(Configuration& configuration, FunctionAdd
         auto lhs = lhs_entry.get<Value>().to<type>();                                               \
         TRAP_IF_NOT(lhs.has_value());                                                               \
         TRAP_IF_NOT(rhs.has_value());                                                               \
+        __VA_ARGS__;                                                                                \
         auto result = operation(lhs.value(), rhs.value());                                          \
         dbgln_if(WASM_TRACE_DEBUG, "{}({} {}) = {}", #operation, lhs.value(), rhs.value(), result); \
         configuration.stack().peek() = Value(cast(result));                                         \
@@ -881,11 +882,11 @@ void BytecodeInterpreter::interpret(Configuration& configuration, InstructionPoi
     case Instructions::i32_popcnt.value():
         UNARY_NUMERIC_OPERATION(i32, __builtin_popcount);
     case Instructions::i32_add.value():
-        BINARY_NUMERIC_OPERATION(i32, +, i32);
+        BINARY_NUMERIC_OPERATION(u32, +, i32);
     case Instructions::i32_sub.value():
-        BINARY_NUMERIC_OPERATION(i32, -, i32);
+        BINARY_NUMERIC_OPERATION(u32, -, i32);
     case Instructions::i32_mul.value():
-        BINARY_NUMERIC_OPERATION(i32, *, i32);
+        BINARY_NUMERIC_OPERATION(u32, *, i32);
     case Instructions::i32_divs.value():
         BINARY_NUMERIC_OPERATION(i32, /, i32, TRAP_IF_NOT(!(Checked<i32>(lhs.value()) /= rhs.value()).has_overflow()));
     case Instructions::i32_divu.value():
@@ -901,15 +902,15 @@ void BytecodeInterpreter::interpret(Configuration& configuration, InstructionPoi
     case Instructions::i32_xor.value():
         BINARY_NUMERIC_OPERATION(i32, ^, i32);
     case Instructions::i32_shl.value():
-        BINARY_NUMERIC_OPERATION(i32, <<, i32);
+        BINARY_NUMERIC_OPERATION(u32, <<, i32, (rhs = rhs.value() % 32));
     case Instructions::i32_shrs.value():
-        BINARY_NUMERIC_OPERATION(i32, >>, i32);
+        BINARY_NUMERIC_OPERATION(u32, >>, i32, (rhs = rhs.value() % 32)); // FIXME: eh, shouldn't we keep lhs as signed?
     case Instructions::i32_shru.value():
-        BINARY_NUMERIC_OPERATION(u32, >>, i32);
+        BINARY_NUMERIC_OPERATION(u32, >>, i32, (rhs = rhs.value() % 32));
     case Instructions::i32_rotl.value():
-        BINARY_PREFIX_NUMERIC_OPERATION(u32, rotl, i32);
+        BINARY_PREFIX_NUMERIC_OPERATION(u32, rotl, i32, (rhs = rhs.value() % 32));
     case Instructions::i32_rotr.value():
-        BINARY_PREFIX_NUMERIC_OPERATION(u32, rotr, i32);
+        BINARY_PREFIX_NUMERIC_OPERATION(u32, rotr, i32, (rhs = rhs.value() % 32));
     case Instructions::i64_clz.value():
         UNARY_NUMERIC_OPERATION(i64, clz);
     case Instructions::i64_ctz.value():
@@ -917,11 +918,11 @@ void BytecodeInterpreter::interpret(Configuration& configuration, InstructionPoi
     case Instructions::i64_popcnt.value():
         UNARY_NUMERIC_OPERATION(i64, __builtin_popcountll);
     case Instructions::i64_add.value():
-        BINARY_NUMERIC_OPERATION(i64, +, i64);
+        BINARY_NUMERIC_OPERATION(u64, +, i64);
     case Instructions::i64_sub.value():
-        BINARY_NUMERIC_OPERATION(i64, -, i64);
+        BINARY_NUMERIC_OPERATION(u64, -, i64);
     case Instructions::i64_mul.value():
-        BINARY_NUMERIC_OPERATION(i64, *, i64);
+        BINARY_NUMERIC_OPERATION(u64, *, i64);
     case Instructions::i64_divs.value():
         OVF_CHECKED_BINARY_NUMERIC_OPERATION(i64, /, i64, TRAP_IF_NOT(rhs.value() != 0));
     case Instructions::i64_divu.value():
@@ -937,15 +938,15 @@ void BytecodeInterpreter::interpret(Configuration& configuration, InstructionPoi
     case Instructions::i64_xor.value():
         BINARY_NUMERIC_OPERATION(i64, ^, i64);
     case Instructions::i64_shl.value():
-        BINARY_NUMERIC_OPERATION(i64, <<, i64);
+        BINARY_NUMERIC_OPERATION(u64, <<, i64, (rhs = rhs.value() % 64));
     case Instructions::i64_shrs.value():
-        BINARY_NUMERIC_OPERATION(i64, >>, i64);
+        BINARY_NUMERIC_OPERATION(u64, >>, i64, (rhs = rhs.value() % 64)); // FIXME: eh, shouldn't we keep lhs as signed?
     case Instructions::i64_shru.value():
-        BINARY_NUMERIC_OPERATION(u64, >>, i64);
+        BINARY_NUMERIC_OPERATION(u64, >>, i64, (rhs = rhs.value() % 64));
     case Instructions::i64_rotl.value():
-        BINARY_PREFIX_NUMERIC_OPERATION(u64, rotl, i64);
+        BINARY_PREFIX_NUMERIC_OPERATION(u64, rotl, i64, (rhs = rhs.value() % 64));
     case Instructions::i64_rotr.value():
-        BINARY_PREFIX_NUMERIC_OPERATION(u64, rotr, i64);
+        BINARY_PREFIX_NUMERIC_OPERATION(u64, rotr, i64, (rhs = rhs.value() % 64));
     case Instructions::f32_abs.value():
         UNARY_NUMERIC_OPERATION(float, fabsf);
     case Instructions::f32_neg.value():