nvmet-tcp: Fix potential UAF when ddgst mismatch

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commit dbbd07d0a7 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 <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>
Signed-off-by: Shivam Kumar <kumar.shivam43666@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

...

This commit is contained in:

Sagi Grimberg 2026-07-21 09:54:38 -04:00 • committed by Greg Kroah-Hartman

parent aabd761612

commit 7e558308eb

1 changed files with 3 additions and 1 deletions

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drivers/nvme/target/tcp.c

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