From 7e558308eba14c8136cb1e615f0c850f76d1fc0a Mon Sep 17 00:00:00 2001 From: Sagi Grimberg Date: Tue, 21 Jul 2026 09:54:38 -0400 Subject: [PATCH] nvmet-tcp: Fix potential UAF when ddgst mismatch commit dbbd07d0a7020b80f6a7028e561908f7b83b3d5a upstream. Shivam Kumar found via vulnerability testing: When data digest is enabled on an NVMe/TCP connection and a digest mismatch occurs on a non-final H2C_DATA PDU during an R2T-based data transfer, the digest error handler in nvmet_tcp_try_recv_ddgst() calls nvmet_req_uninit() - which performs percpu_ref_put() on the submission queue - but does NOT mark the command as completed. It does not set cqe->status, does not modify rbytes_done, and does not clear any flag. When the subsequent fatal error triggers queue teardown, nvmet_tcp_uninit_data_in_cmds() iterates all commands, checks nvmet_tcp_need_data_in() for each one, and finds that the already-uninited command still appears to need data (because rbytes_done < transfer_len and cqe->status == 0). It therefore calls nvmet_req_uninit() a second time on the same command - a double percpu_ref_put against a single percpu_ref_get. Reported-by: Shivam Kumar Reviewed-by: Christoph Hellwig Signed-off-by: Sagi Grimberg Signed-off-by: Keith Busch Signed-off-by: Shivam Kumar Signed-off-by: Sasha Levin --- drivers/nvme/target/tcp.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/nvme/target/tcp.c b/drivers/nvme/target/tcp.c index 95081052dce7..8fe51218441e 100644 --- a/drivers/nvme/target/tcp.c +++ b/drivers/nvme/target/tcp.c @@ -1239,8 +1239,10 @@ static int nvmet_tcp_try_recv_ddgst(struct nvmet_tcp_queue *queue) queue->idx, cmd->req.cmd->common.command_id, queue->pdu.cmd.hdr.type, le32_to_cpu(cmd->recv_ddgst), le32_to_cpu(cmd->exp_ddgst)); - if (!(cmd->flags & NVMET_TCP_F_INIT_FAILED)) + if (!(cmd->flags & NVMET_TCP_F_INIT_FAILED)) { + cmd->req.cqe->status = NVME_SC_CMD_SEQ_ERROR; nvmet_req_uninit(&cmd->req); + } nvmet_tcp_free_cmd_buffers(cmd); nvmet_tcp_fatal_error(queue); ret = -EPROTO;