Duplicate slice passed to mongocrypt.newBinaryFromBytes().

x/mongo/driver/mongocrypt/binary.go

@@ -9,14 +9,18 @@
 
 package mongocrypt
 
-// #include <mongocrypt.h>
+/*
+#include <stdlib.h>
+#include <mongocrypt.h>
+*/
 import "C"
 import (
 	"unsafe"
 )
 
 // binary is a wrapper type around a mongocrypt_binary_t*
 type binary struct {
+	p       *C.uint8_t
 	wrapped *C.mongocrypt_binary_t
 }
 
@@ -33,11 +37,11 @@ func newBinaryFromBytes(data []byte) *binary {
 		return newBinary()
 	}
 
-	// We don't need C.CBytes here because data cannot go out of scope. Any mongocrypt function that takes a
-	// mongocrypt_binary_t will make a copy of the data so the data can be garbage collected after calling.
-	addr := (*C.uint8_t)(unsafe.Pointer(&data[0])) // uint8_t*
-	dataLen := C.uint32_t(len(data))               // uint32_t
+	// TODO: Consider using runtime.Pinner to replace the C.CBytes after using go1.21.0.
+	addr := (*C.uint8_t)(C.CBytes(data)) // uint8_t*
+	dataLen := C.uint32_t(len(data))     // uint32_t
 	return &binary{
+		p:       addr,
 		wrapped: C.mongocrypt_binary_new_from_data(addr, dataLen),
 	}
 }
@@ -52,5 +56,8 @@ func (b *binary) toBytes() []byte {
 
 // close cleans up any resources associated with the given binary instance.
 func (b *binary) close() {
+	if b.p != nil {
+		C.free(unsafe.Pointer(b.p))
+	}
 	C.mongocrypt_binary_destroy(b.wrapped)
 }