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Fix overflow handlings for Uint, add more test cases around IntSort overflows #1143

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Merged
copybara-service merged 1 commit into from
Jul 23, 2026
+53 −6
Merged

Fix overflow handlings for Uint, add more test cases around IntSort overflows #1143

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14 changes: 9 additions & 5 deletions verifier/src/main/java/dev/cel/verifier/CelZ3TypeSystem.java
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Original file line number Diff line number Diff line change
Expand Up @@ -16,6 +16,7 @@

import com.google.common.collect.Lists;
import com.google.common.collect.ObjectArrays;
import com.google.common.primitives.UnsignedLongs;
import com.google.errorprone.annotations.CanIgnoreReturnValue;
import com.microsoft.z3.ArithExpr;
import com.microsoft.z3.ArrayExpr;
Expand Down Expand Up @@ -300,9 +301,14 @@ public Expr<?> mkInt(long val) {
return ctx.mkApp(intCons.ConstructorDecl(), ctx.mkInt(val));
}

/** Creates a CelValue containing an unsigned integer from a string representation. */
public Expr<?> mkUint(String val) {
return ctx.mkApp(uintCons.ConstructorDecl(), ctx.mkInt(val));
}

/** Creates a CelValue containing an unsigned integer. */
public Expr<?> mkUint(long val) {
return ctx.mkApp(uintCons.ConstructorDecl(), ctx.mkInt(val));
return mkUint(UnsignedLongs.toString(val));
}

/** Creates a CelValue containing a double. */
Expand Down Expand Up @@ -859,10 +865,8 @@ public static BoolExpr mkNotFlattened(Context ctx, BoolExpr arg) {
this.boolCons =
ctx.mkConstructor(
CONS_BOOL, IS_BOOL, new String[] {GET_BOOL}, new Sort[] {ctx.getBoolSort()}, null);
// Note: Z3's IntSort models unbounded mathematical integers. We do not currently use
// BitVecSort(64), which means CEL integer overflow semantics are not natively modeled,
// and bitwise operations are unsupported. We enforce 64-bit value bounds explicitly
// during variable constraint generation instead.
// We use Z3's IntSort instead of BitVecSort(64) for faster arithmetic solving without
// bit-blasting, explicitly enforcing 64-bit range bounds and overflow errors.
this.intCons =
ctx.mkConstructor(
CONS_INT, IS_INT, new String[] {GET_INT}, new Sort[] {ctx.getIntSort()}, null);
Expand Down
45 changes: 44 additions & 1 deletion verifier/src/test/java/dev/cel/verifier/CelVerifierZ3ImplTest.java
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Expand Up @@ -84,6 +84,8 @@ public final class CelVerifierZ3ImplTest {
.addMessageTypes(TestAllTypes.getDescriptor(), TestAllTypes.NestedMessage.getDescriptor())
.addVar("x", SimpleType.INT)
.addVar("u", SimpleType.UINT)
.addVar("u1", SimpleType.UINT)
.addVar("u2", SimpleType.UINT)
.addVar("d", SimpleType.DOUBLE)
.addVar("by", SimpleType.BYTES)
.addVar("y", SimpleType.INT)
Expand Down Expand Up @@ -705,6 +707,10 @@ private enum IsAlwaysTrueTestCase {
DYNAMIC_NUMERIC_EQUALITY_CROSS_TYPE_DYN_DOUBLE(
"type(dyn_var) == double && dyn_var == 5.0 && dyn_var2 == 5.0 && type(dyn_var2) == double ?"
+ " dyn_var == dyn_var2 : true"),
INT64_BOUNDS_ALWAYS_TRUE("x <= 9223372036854775807 && x >= -9223372036854775808"),
UINT64_BOUNDS_ALWAYS_TRUE("u <= 18446744073709551615u && u >= 0u"),
MODULO_INT64_MIN_INT_BY_NEG_ONE_ALWAYS_ZERO(
"x == -9223372036854775808 && y == -1 ? x % y == 0 : true"),
;

final String expr;
Expand Down Expand Up @@ -1203,7 +1209,44 @@ private enum IsAlwaysTrueViolationTestCase {
"type(dyn_var) == int ? (dyn_var ? true : false) == (dyn_var ? true : false) : true",
"Condition is not always true\\.",
"Counterexample input:",
"dyn_var = int\\{\\}");
"dyn_var = int\\{\\}"),
ADD_INT64_OVERFLOW_FAILS_WITH_ERRORS(
"x > 0 && y > 0 ? x + y > x : true",
"Condition is not always true\\.",
"Counterexample input:",
"x = (1|9223372036854775807)",
"y = (1|9223372036854775807)"),
ADD_UINT64_OVERFLOW_FAILS_WITH_ERRORS(
"u1 > 0u && u2 > 0u ? u1 + u2 >= u1 : true",
"Condition is not always true\\.",
"Counterexample input:",
"u1 = (1u|18446744073709551615u)",
"u2 = (1u|18446744073709551615u)"),
SUBTRACT_INT64_UNDERFLOW_FAILS_WITH_ERRORS(
"x < 0 && y > 0 ? x - y < x : true",
"Condition is not always true\\.",
"Counterexample input:",
"x = (-2|9223372036854775807)",
"y = (-2|9223372036854775807)"),
MULTIPLY_INT64_OVERFLOW_FAILS_WITH_ERRORS(
"x > 1000000000 && y > 1000000000 ? x * y > 0 : true",
"Condition is not always true\\.",
"Counterexample input:",
"x = [0-9]+",
"y = [0-9]+"),
MULTIPLY_UINT64_OVERFLOW_FAILS_WITH_ERRORS(
"u1 > 1000000000u && u2 > 1000000000u ? u1 * u2 > 0u : true",
"Condition is not always true\\.",
"Counterexample input:",
"u1 = [0-9]+u",
"u2 = [0-9]+u"),
DIVIDE_INT64_OVERFLOW_MIN_INT_BY_NEG_ONE_FAILS_WITH_ERRORS(
"x == -9223372036854775808 && y == -1 ? x / y == -x : true",
"Condition is not always true\\.",
"Counterexample input:",
"x = -9223372036854775808",
"y = -1"),
;

final String expr;
final ImmutableList<String> expectedFragments;
Expand Down
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