From: Akihiko Odaki Date: Wed, 8 Jan 2025 11:31:46 +0000 (+0900) Subject: hw/xen: Check if len is 0 before memcpy() X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=b6014c5089a313ac84fe74970eee56e3fc87b49b;p=qemu.git hw/xen: Check if len is 0 before memcpy() data->data can be NULL when len is 0. Strictly speaking, the behavior of memcpy() in such a scenario is undefined so UBSan complaints. Satisfy UBSan by checking if len is 0 before memcpy(). Signed-off-by: Akihiko Odaki Reviewed-by: Philippe Mathieu-Daudé Signed-off-by: David Woodhouse --- diff --git a/hw/i386/kvm/xen_xenstore.c b/hw/i386/kvm/xen_xenstore.c index 5969105667..17802aa33d 100644 --- a/hw/i386/kvm/xen_xenstore.c +++ b/hw/i386/kvm/xen_xenstore.c @@ -532,6 +532,10 @@ static void xs_read(XenXenstoreState *s, unsigned int req_id, return; } + if (!len) { + return; + } + memcpy(&rsp_data[rsp->len], data->data, len); rsp->len += len; }