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([187.13.206.89]) by smtp.gmail.com with ESMTPSA id 71dfb90a1353d-5c84716a167sm16029131e0c.18.2026.09.15.07.16.02 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 15 Sep 2026 07:16:04 -0700 (PDT) From: Aldo Ariel Panzardo To: Stefano Garzarella Cc: virtualization@lists.linux.dev, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, Aldo Ariel Panzardo Subject: [PATCH v2] vsock: ignore empty child namespace mode writes Date: Tue, 15 Sep 2026 11:15:47 -0300 Message-ID: <20260915141547.3010692-1-qwe.aldo@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260915111417.2726515-1-qwe.aldo@gmail.com> References: <20260915111417.2726515-1-qwe.aldo@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit __vsock_net_mode_string() returns success without updating new_mode when the transfer length is zero. Its caller then reads the uninitialized enum and may permanently store a stack-derived value in the write-once child mode. Return before inspecting or storing new_mode when no bytes were transferred. This also prevents an empty write from locking the current mode. Fixes: eafb64f40ca4 ("vsock: add netns to vsock core") Cc: stable@vger.kernel.org Signed-off-by: Aldo Ariel Panzardo --- net/vmw_vsock/af_vsock.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c index 622dbd0467..816d25b314 100644 --- a/net/vmw_vsock/af_vsock.c +++ b/net/vmw_vsock/af_vsock.c @@ -2883,6 +2883,8 @@ static int vsock_net_child_mode_string(const struct ctl_table *table, int write, vsock_net_child_mode(net), &new_mode); if (ret) return ret; + if (!*lenp) + return 0; if (write) { /* Prevent a "local" namespace from escalating to "global", -- 2.43.0