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[82.53.134.58]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-43569921facsm33887841f8f.5.2026.01.21.01.36.29 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 21 Jan 2026 01:36:30 -0800 (PST) From: Stefano Garzarella To: netdev@vger.kernel.org Cc: Simon Horman , Eric Dumazet , "Michael S. Tsirkin" , Arseniy Krasnov , "David S. Miller" , Stefano Garzarella , virtualization@lists.linux.dev, Paolo Abeni , Jakub Kicinski , Stefan Hajnoczi , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Claudio Imbrenda , Jason Wang , Xuan Zhuo , =?UTF-8?q?Eugenio=20P=C3=A9rez?= , Asias He Subject: [PATCH net v6 0/4] vsock/virtio: fix TX credit handling Date: Wed, 21 Jan 2026 10:36:24 +0100 Message-ID: <20260121093628.9941-1-sgarzare@redhat.com> X-Mailer: git-send-email 2.52.0 Content-Type: text/plain; charset="utf-8" Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit The original series was posted by Melbin K Mathew 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/20260116201517.273302-1-sgarzare@redhat.com/ v4: https://lore.kernel.org/netdev/20251217181206.3681159-1-mlbnkm1@gmail.com/ >From Melbin K Mathew : 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