Subject: FAILED: patch "[PATCH] nvmet-tcp: Fix potential UAF when ddgst mismatch" failed to apply to 5.10-stable tree
To: sagi@grimberg.me,hch@lst.de,kbusch@kernel.org,kumar.shivam43666@gmail.com
Cc: <stable@vger.kernel.org>
From: <gregkh@linuxfoundation.org>
Date: Sun, 19 Jul 2026 14:14:00 +0200
Message-ID: <2026071900-poster-swear-030a@gregkh>
Precedence: bulk
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The patch below does not apply to the 5.10-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.10.y
git checkout FETCH_HEAD
git cherry-pick -x dbbd07d0a7020b80f6a7028e561908f7b83b3d5a
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2026071900-poster-swear-030a@gregkh' --subject-prefix 'PATCH 5.10.y' 'HEAD^..'

Possible dependencies:


thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From dbbd07d0a7020b80f6a7028e561908f7b83b3d5a Mon Sep 17 00:00:00 2001
From: Sagi Grimberg <sagi@grimberg.me>
Date: Sun, 10 May 2026 23:30:29 +0300
Subject: [PATCH] nvmet-tcp: Fix potential UAF when ddgst mismatch
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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 <kumar.shivam43666@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Keith Busch <kbusch@kernel.org>

diff --git a/drivers/nvme/target/tcp.c b/drivers/nvme/target/tcp.c
index 164a564ba3b4..20f150d17a96 100644
--- a/drivers/nvme/target/tcp.c
+++ b/drivers/nvme/target/tcp.c
@@ -1321,8 +1321,10 @@ 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);
 		ret = -EPROTO;
 		goto out;