From: Yehyeong Lee <yhlee@isslab.korea.ac.kr> mainline inclusion from mainline-v7.3-rc1 commit 6efbc52237facda35d2d874fe1765bb4839275d8 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/18846 CVE: CVE-2026-89481 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- nvme_tcp_handle_r2t() does not check the direction of the request the R2T refers to. A malicious controller can send an R2T for a READ and the host will answer it: nvme_tcp_setup_h2c_data_pdu() builds the H2CData header and nvme_tcp_try_send_data() sends the request's data buffer. That buffer is the READ destination, so its contents go to the controller. The command then completes normally and nothing is logged. Against a test controller that answers every READ with an R2T, a 4096 byte buffered read returned all 4096 bytes, split over two R2Ts. The pages contained stale kernel data, including an array of struct page pointers. Reject an R2T for a request that is not a write. Fixes: 3f2304f8c6d6 ("nvme-tcp: add NVMe over TCP host driver") Cc: stable@vger.kernel.org Signed-off-by: Yehyeong Lee <yhlee@isslab.korea.ac.kr> Signed-off-by: Keith Busch <kbusch@kernel.org> Conflicts: drivers/nvme/host/tcp.c [Upstream commit 1d3ef9c3a39e ("nvme-tcp: validate R2T PDU in nvme_tcp_handle_r2t()") is not backported, so there is no standalone r2t_length check after req = blk_mq_rq_to_pdu(rq); insert the rq_data_dir() check right after it, before nvme_tcp_setup_h2c_data_pdu().] Signed-off-by: Chen Yuxi <chenyuxi19@huawei.com> --- drivers/nvme/host/tcp.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/nvme/host/tcp.c b/drivers/nvme/host/tcp.c index 89cef71def14..586f47e47b11 100644 --- a/drivers/nvme/host/tcp.c +++ b/drivers/nvme/host/tcp.c @@ -680,6 +680,13 @@ static int nvme_tcp_handle_r2t(struct nvme_tcp_queue *queue, } req = blk_mq_rq_to_pdu(rq); + if (unlikely(rq_data_dir(rq) != WRITE)) { + dev_err(queue->ctrl->ctrl.device, + "req %d unexpected r2t for a non-write command\n", + rq->tag); + return -EPROTO; + } + ret = nvme_tcp_setup_h2c_data_pdu(req, pdu); if (unlikely(ret)) return ret; -- 2.34.1