linux-kernel - [PATCH v2] nvme-rdma: handle nvme completion data length

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-Id: <20201023065910.1358586-1-pizhenwei@bytedance.com>
Date:   Fri, 23 Oct 2020 14:59:10 +0800
From:   zhenwei pi <pizhenwei@...edance.com>
To:     kbusch@...nel.org, hch@....de, sagi@...mberg.me, axboe@...com
Cc:     linux-nvme@...ts.infradead.org, linux-kernel@...r.kernel.org,
        pizhenwei@...edance.com
Subject: [PATCH v2] nvme-rdma: handle nvme completion data length

Hit a kernel warning:
refcount_t: underflow; use-after-free.
WARNING: CPU: 0 PID: 0 at lib/refcount.c:28

RIP: 0010:refcount_warn_saturate+0xd9/0xe0
Call Trace:
 <IRQ>
 nvme_rdma_recv_done+0xf3/0x280 [nvme_rdma]
 __ib_process_cq+0x76/0x150 [ib_core]
 ...

The reason is that a zero bytes message received from target, and the
host side continues to process without length checking, then the
previous CQE is processed twice.

Handle data length, ignore zero bytes message, and try to recovery for
corrupted CQE case.

Thanks to Chao Leng for suggestions.

Signed-off-by: zhenwei pi <pizhenwei@...edance.com>
---
 drivers/nvme/host/rdma.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/drivers/nvme/host/rdma.c b/drivers/nvme/host/rdma.c
index 9e378d0a0c01..2ecadd309f4a 100644
--- a/drivers/nvme/host/rdma.c
+++ b/drivers/nvme/host/rdma.c
@@ -1767,6 +1767,21 @@ static void nvme_rdma_recv_done(struct ib_cq *cq, struct ib_wc *wc)
 		return;
 	}
 
+	/* received data length checking */
+	if (unlikely(wc->byte_len < len)) {
+		/* zero bytes message could be ignored */
+		if (!wc->byte_len) {
+			nvme_rdma_post_recv(queue, qe);
+			return;
+		}
+
+		/* corrupted completion, try to recovry */
+		dev_err(queue->ctrl->ctrl.device,
+			"Unexpected nvme completion length(%d)\n", wc->byte_len);
+		nvme_rdma_error_recovery(queue->ctrl);
+		return;
+	}
+
 	ib_dma_sync_single_for_cpu(ibdev, qe->dma, len, DMA_FROM_DEVICE);
 	/*
 	 * AEN requests are special as they don't time out and can
-- 
2.11.0