The original series was posted by Melbin K Mathew <[email protected]> till v4. Since it's a real issue and the original author seems busy, I'm sending the new version fixing my comments but keeping the authorship (and restoring mine on patch 2 as reported on v4).
v6: - Rebased on net tree since there was a conflict on patch 4 with another test added. - No code changes. v5: https://lore.kernel.org/netdev/[email protected]/ v4: https://lore.kernel.org/netdev/[email protected]/ >From Melbin K Mathew <[email protected]>: This series fixes TX credit handling in virtio-vsock: Patch 1: Fix potential underflow in get_credit() using s64 arithmetic Patch 2: Fix vsock_test seqpacket bounds test Patch 3: Cap TX credit to local buffer size (security hardening) Patch 4: Add stream TX credit bounds regression test The core issue is that a malicious guest can advertise a huge buffer size via SO_VM_SOCKETS_BUFFER_SIZE, causing the host to allocate excessive sk_buff memory when sending data to that guest. On an unpatched Ubuntu 22.04 host (~64 GiB RAM), running a PoC with 32 guest vsock connections advertising 2 GiB each and reading slowly drove Slab/SUnreclaim from ~0.5 GiB to ~57 GiB; the system only recovered after killing the QEMU process. With this series applied, the same PoC shows only ~35 MiB increase in Slab/SUnreclaim, no host OOM, and the guest remains responsive. Melbin K Mathew (3): vsock/virtio: fix potential underflow in virtio_transport_get_credit() vsock/virtio: cap TX credit to local buffer size vsock/test: add stream TX credit bounds test Stefano Garzarella (1): vsock/test: fix seqpacket message bounds test net/vmw_vsock/virtio_transport_common.c | 30 +++++-- tools/testing/vsock/vsock_test.c | 112 ++++++++++++++++++++++++ 2 files changed, 133 insertions(+), 9 deletions(-) -- 2.52.0
