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Ziyi Guo
2993e0f904
[ Upstream commit6d1dc80143] A malicious or buggy Xen guest can write "0" to the xenbus key "multi-queue-num-queues". The connect() function in the backend only validates the upper bound (requested_num_queues > xenvif_max_queues) but not zero, allowing requested_num_queues=0 to reach vzalloc(array_size(0, sizeof(struct xenvif_queue))), which triggers WARN_ON_ONCE(!size) in __vmalloc_node_range(). On systems with panic_on_warn=1, this allows a guest-to-host denial of service. The Xen network interface specification requires the queue count to be "greater than zero". Add a zero check to match the validation already present in xen-blkback, which has included this guard since its multi-queue support was added. Fixes:8d3d53b3e4("xen-netback: Add support for multiple queues") Signed-off-by: Ziyi Guo <n7l8m4@u.northwestern.edu> Reviewed-by: Juergen Gross <jgross@suse.com> Link: https://patch.msgid.link/20260212224040.86674-1-n7l8m4@u.northwestern.edu Signed-off-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org>