From: Lennart Poettering <lennart@poettering.net>
Date: Mon, 25 May 2020 16:21:08 +0000 (+0200)
Subject: json: turn off ubsan for json_variant_has_type()
X-Git-Tag: v246-rc1~292^2~1
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=8e2fa6e2236ec81c86612f75103f36ba699193c8;p=thirdparty%2Fsystemd.git

json: turn off ubsan for json_variant_has_type()

Fixes: #15907
---

diff --git a/src/basic/macro.h b/src/basic/macro.h
index 73b391c27c8..b48d3990972 100644
--- a/src/basic/macro.h
+++ b/src/basic/macro.h
@@ -84,6 +84,14 @@
 #define _variable_no_sanitize_address_
 #endif
 
+/* Apparently there's no has_feature() call defined to check for ubsan, hence let's define this
+ * unconditionally on llvm */
+#if defined(__clang__)
+#define _function_no_sanitize_float_cast_overflow_ __attribute__((no_sanitize("float-cast-overflow")))
+#else
+#define _function_no_sanitize_float_cast_overflow_
+#endif
+
 /* Temporarily disable some warnings */
 #define DISABLE_WARNING_FORMAT_NONLITERAL                               \
         _Pragma("GCC diagnostic push");                                 \
diff --git a/src/shared/json.c b/src/shared/json.c
index a3ad5b996a7..27a3a518fef 100644
--- a/src/shared/json.c
+++ b/src/shared/json.c
@@ -1093,9 +1093,12 @@ JsonVariantType json_variant_type(JsonVariant *v) {
         return v->type;
 }
 
-bool json_variant_has_type(JsonVariant *v, JsonVariantType type) {
+_function_no_sanitize_float_cast_overflow_ bool json_variant_has_type(JsonVariant *v, JsonVariantType type) {
         JsonVariantType rt;
 
+        /* Note: we turn off ubsan float cast overflo detection for this function, since it would complain
+         * about our float casts but we do them explicitly to detect conversion errors. */
+
         v = json_variant_dereference(v);
         if (!v)
                 return false;