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Ayush RanjanandAlessio Ricci Toniolo
83f9a0d16e
Add pkg/sentry/devices/rdmaproxy, a passthrough proxy for /dev/infiniband/uverbs* that lets a sandboxed application drive RDMA verbs against the host's ib_uverbs devices. The proxy forwards the modern RDMA_VERBS_IOCTL to a host uverbs FD. Every request is validated against an explicit per-(object, method) schema, and each attribute is translated strictly by its schema-declared ABI type rather than by probing guest memory: input pointers are copied into sentry buffers, output buffers are staged and copied back, object handles are passed through, and file descriptors are translated between the sandbox and the host. Interpreting an attribute's direction from the fixed kernel ABI (additive-only, stable since Linux 4.20) instead of from the guest's memory is what prevents a malicious guest from coercing the proxy into an out-of-bounds copy. DMA buffers referenced by memory-region registrations and by the vendor driver-private CQ/QP data are pinned and mirrored into the sentry's address space so the host kernel can pin_user_pages on them. The mlx5 (ConnectX) driver-private layout lives in a vendor plug-in, pkg/sentry/devices/rdmaproxy/ cxproxy, registered with the core at init time. A new MemoryManager.FindVMARange helper bounds a driver-private DMA buffer whose backing region the guest describes by start address only. Co-authored-by: Alessio Ricci Toniolo <[email protected]>