Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
From:   Tuo Li <islituo@gmail.com>
To:     mike.marciniszyn@cornelisnetworks.com,
        dennis.dalessandro@cornelisnetworks.com, dledford@redhat.com,
        jgg@ziepe.ca
Cc:     linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org,
        baijiaju1990@gmail.com, Tuo Li <islituo@gmail.com>,
        TOTE Robot <oslab@tsinghua.edu.cn>
Subject: [PATCH] IB/hfi1: Fix possible null-pointer dereference in _extend_sdma_tx_descs()
Date:   Thu,  5 Aug 2021 05:24:12 -0700
Message-Id: <20210805122412.130007-1-islituo@gmail.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

kmalloc_array() is called to allocate memory for tx->descp. If it fails, 
the function __sdma_txclean() is called:
  __sdma_txclean(dd, tx);

However, in the function __sdma_txclean(), tx-descp is dereferenced if 
tx->num_desc is not zero:
  sdma_unmap_desc(dd, &tx->descp[0]);

To fix this possible null-pointer dereference, assign 0 to tx->num_desc if
kmalloc_array() returns NULL.

Reported-by: TOTE Robot <oslab@tsinghua.edu.cn>
Signed-off-by: Tuo Li <islituo@gmail.com>
---
 drivers/infiniband/hw/hfi1/sdma.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/infiniband/hw/hfi1/sdma.c b/drivers/infiniband/hw/hfi1/sdma.c
index eb15c310d63d..00e29c3dfe96 100644
--- a/drivers/infiniband/hw/hfi1/sdma.c
+++ b/drivers/infiniband/hw/hfi1/sdma.c
@@ -3079,8 +3079,10 @@ static int _extend_sdma_tx_descs(struct hfi1_devdata *dd, struct sdma_txreq *tx)
 			MAX_DESC,
 			sizeof(struct sdma_desc),
 			GFP_ATOMIC);
-	if (!tx->descp)
+	if (!tx->descp) {
+		tx->num_desc = 0;
 		goto enomem;
+	}
 
 	/* reserve last descriptor for coalescing */
 	tx->desc_limit = MAX_DESC - 1;
-- 
2.25.1