fuse_lib_ioctl(): don't call memcpy with NULL argument

This was detected by using clang's undefined behavior sanitizer, but
didn't seem to cause problems in practice.

1 files changed, 1 insertions, 1 deletions

diff --git a/lib/fuse.c b/lib/fuse.c
index 5cc4e42..7b0b979 100644
--- a/lib/fuse.c
+++ b/lib/fuse.c
@@ -4148,7 +4148,7 @@ static void fuse_lib_ioctl(fuse_req_t req, fuse_ino_t ino, int cmd, void *arg,
 	}
 
 	assert(!in_bufsz || !out_bufsz || in_bufsz == out_bufsz);
-	if (out_buf)
+	if (out_buf && in_bufsz)
 		memcpy(out_buf, in_buf, in_bufsz);
 
 	err = get_path_nullok(f, ino, &path);