Fix UB in right shift (#10422)

yumkam · web-flow · commit a4c9ddf05675 · 2024-10-16T11:46:51.000+03:00
diff --git a/ydb/library/yql/udfs/common/ip_base/lib/ip_base_udf.h b/ydb/library/yql/udfs/common/ip_base/lib/ip_base_udf.h
@@ -95,8 +95,7 @@ namespace {
         }
 
         static TRawIp6 MaskFromPrefix(ui8 prefix) {
-            ui128 x = ui128(-1) << int(128 - prefix);
-            if (prefix == 0) x = 0;
+            ui128 x = prefix == 0 ? ui128(0) : ui128(-1) << int(128 - prefix);
             return FromIpAddress({x, TIpv6Address::Ipv6});
         }
 

Original file line number	Diff line number	Diff line change
`@@ -95,8 +95,7 @@ namespace {`
`95`	`95`	`}`
`96`	`96`
`97`	`97`	`static TRawIp6 MaskFromPrefix(ui8 prefix) {`
`98`		`- ui128 x = ui128(-1) << int(128 - prefix);`
`99`		`- if (prefix == 0) x = 0;`
	`98`	`+ ui128 x = prefix == 0 ? ui128(0) : ui128(-1) << int(128 - prefix);`
`100`	`99`	`return FromIpAddress({x, TIpv6Address::Ipv6});`
`101`	`100`	`}`
`102`	`101`