net: clear malloc'ed memory in cgoResSearch

For #61666 Change-Id: I7a0a849fba0abebe28804bdd6d364b154456e399 Reviewed-on: https://go-review.googlesource.com/c/go/+/534516 Run-TryBot: Ian Lance Taylor <[email protected]> TryBot-Result: Gopher Robot <[email protected]> Reviewed-by: Damien Neil <[email protected]> Auto-Submit: Ian Lance Taylor <[email protected]> Reviewed-by: Ian Lance Taylor <[email protected]>
golang · Oct 11, 2023 · 3b0fc5a · 3b0fc5a
1 parent 655155d
commit 3b0fc5a
Showing 1 changed file with 9 additions and 2 deletions.
diff --git a/src/net/cgo_unix.go b/src/net/cgo_unix.go
@@ -319,8 +319,15 @@ func cgoResSearch(hostname string, rtype, class int) ([]dnsmessage.Resource, err
 	acquireThread()
 	defer releaseThread()
 
-	state := (*_C_struct___res_state)(_C_malloc(unsafe.Sizeof(_C_struct___res_state{})))
-	defer _C_free(unsafe.Pointer(state))
+	resStateSize := unsafe.Sizeof(_C_struct___res_state{})
+	var state *_C_struct___res_state
+	if resStateSize > 0 {
+		mem := _C_malloc(resStateSize)
+		defer _C_free(mem)
+		memSlice := unsafe.Slice((*byte)(mem), resStateSize)
+		clear(memSlice)
+		state = (*_C_struct___res_state)(unsafe.Pointer(&memSlice[0]))
+	}
 	if err := _C_res_ninit(state); err != nil {
 		return nil, errors.New("res_ninit failure: " + err.Error())
 	}