From 8fff3c76b9b1e7de4aa9b0cdb0989c72a88b15fc Mon Sep 17 00:00:00 2001
From: Tim Wojtulewicz <tim@corelight.com>
Date: Thu, 21 Jul 2022 13:03:16 -0700
Subject: [PATCH] Handle error cases for bit-shift operators more cleanly

---
 src/Expr.cc                             | 40 +++++++++++++++++++++++--
 testing/btest/Baseline/language.int/out |  1 +
 testing/btest/language/int.zeek         |  4 +--
 3 files changed, 41 insertions(+), 4 deletions(-)

diff --git a/src/Expr.cc b/src/Expr.cc
index 7ba9559509..3882b9ca89 100644
--- a/src/Expr.cc
+++ b/src/Expr.cc
@@ -960,11 +960,47 @@ ValPtr BinaryExpr::Fold(Val* v1, Val* v2) const
 			DO_UINT_FOLD(^);
 			break;
 		case EXPR_LSHIFT:
-			DO_INT_FOLD(<<);
+			{
+			if ( is_integral )
+				{
+				if ( i2 < 0 )
+					RuntimeError("left shift by negative value");
+				else if ( i1 < 1 )
+					RuntimeError("left shifting a negative number is undefined");
+
+				i3 = i1 << i2;
+				}
+			else if ( is_unsigned )
+				{
+				if ( u2 < 0 )
+					RuntimeError("left shift by negative value");
+
+				u3 = u1 << u2;
+				}
+			else
+				RuntimeErrorWithCallStack("bad type in BinaryExpr::Fold");
 			break;
+			}
 		case EXPR_RSHIFT:
-			DO_INT_FOLD(>>);
+			{
+			if ( is_integral )
+				{
+				if ( i2 < 0 )
+					RuntimeError("right shift by negative value");
+
+				i3 = i1 >> i2;
+				}
+			else if ( is_unsigned )
+				{
+				if ( u2 < 0 )
+					RuntimeError("right shift by negative value");
+
+				u3 = u1 >> u2;
+				}
+			else
+				RuntimeErrorWithCallStack("bad type in BinaryExpr::Fold");
 			break;
+			}
 
 		case EXPR_AND_AND:
 			DO_INT_FOLD(&&);
diff --git a/testing/btest/Baseline/language.int/out b/testing/btest/Baseline/language.int/out
index b2f4f2c04a..f01f5a3de1 100644
--- a/testing/btest/Baseline/language.int/out
+++ b/testing/btest/Baseline/language.int/out
@@ -18,6 +18,7 @@ modulus operator (PASS)
 division operator (PASS)
 assignment operator (PASS)
 assignment operator (PASS)
+bitwise lshift (PASS)
 bitwise rshift (PASS)
 max int value = 9223372036854775807 (PASS)
 min int value = -9223372036854775808 (PASS)
diff --git a/testing/btest/language/int.zeek b/testing/btest/language/int.zeek
index 1f010e8048..469cd56e07 100644
--- a/testing/btest/language/int.zeek
+++ b/testing/btest/language/int.zeek
@@ -54,7 +54,8 @@ event zeek_init()
 	test_case( "assignment operator", i2 == 7 );
 	i2 -= 2;
 	test_case( "assignment operator", i2 == 5 );
-	test_case( "bitwise rshift", i10 >> 1 == -6 );
+	test_case( "bitwise lshift", i6 << 1 == 24 );
+	test_case( "bitwise rshift", i6 >> 1 == 6 );
 
 	# Max/min value tests
 
@@ -68,4 +69,3 @@ event zeek_init()
 	test_case( str4, str4 == "min int value = -9223372036854775808" );
 
 }
-