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From:   Daniil Tatianin <d-tatianin@yandex-team.ru>
To:     Shahed Shaikh <shshaikh@marvell.com>
Cc:     Daniil Tatianin <d-tatianin@yandex-team.ru>,
        Manish Chopra <manishc@marvell.com>,
        GR-Linux-NIC-Dev@marvell.com,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: [PATCH v1] qlcnic: prevent ->dcb use-after-free on qlcnic_dcb_enable() failure
Date:   Tue, 20 Dec 2022 15:56:49 +0300
Message-Id: <20221220125649.1637829-1-d-tatianin@yandex-team.ru>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

adapter->dcb would get silently freed inside qlcnic_dcb_enable() in
case qlcnic_dcb_attach() would return an error, which always happens
under OOM conditions. This would lead to use-after-free because both
of the existing callers invoke qlcnic_dcb_get_info() on the obtained
pointer, which is potentially freed at that point.

Propagate errors from qlcnic_dcb_enable(), and instead free the dcb
pointer at callsite.

Found by Linux Verification Center (linuxtesting.org) with the SVACE
static analysis tool.

Signed-off-by: Daniil Tatianin <d-tatianin@yandex-team.ru>
---
 drivers/net/ethernet/qlogic/qlcnic/qlcnic_83xx_init.c | 9 ++++++++-
 drivers/net/ethernet/qlogic/qlcnic/qlcnic_dcb.h       | 5 ++---
 drivers/net/ethernet/qlogic/qlcnic/qlcnic_main.c      | 9 ++++++++-
 3 files changed, 18 insertions(+), 5 deletions(-)

diff --git a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_83xx_init.c b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_83xx_init.c
index dbb800769cb6..465f149d94d4 100644
--- a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_83xx_init.c
+++ b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_83xx_init.c
@@ -2505,7 +2505,14 @@ int qlcnic_83xx_init(struct qlcnic_adapter *adapter)
 		goto disable_mbx_intr;
 
 	qlcnic_83xx_clear_function_resources(adapter);
-	qlcnic_dcb_enable(adapter->dcb);
+
+	err = qlcnic_dcb_enable(adapter->dcb);
+	if (err) {
+		qlcnic_clear_dcb_ops(adapter->dcb);
+		adapter->dcb = NULL;
+		goto disable_mbx_intr;
+	}
+
 	qlcnic_83xx_initialize_nic(adapter, 1);
 	qlcnic_dcb_get_info(adapter->dcb);
 
diff --git a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_dcb.h b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_dcb.h
index 7519773eaca6..e1460f9c38bf 100644
--- a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_dcb.h
+++ b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_dcb.h
@@ -112,9 +112,8 @@ static inline void qlcnic_dcb_init_dcbnl_ops(struct qlcnic_dcb *dcb)
 		dcb->ops->init_dcbnl_ops(dcb);
 }
 
-static inline void qlcnic_dcb_enable(struct qlcnic_dcb *dcb)
+static inline int qlcnic_dcb_enable(struct qlcnic_dcb *dcb)
 {
-	if (dcb && qlcnic_dcb_attach(dcb))
-		qlcnic_clear_dcb_ops(dcb);
+	return dcb ? qlcnic_dcb_attach(dcb) : 0;
 }
 #endif
diff --git a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_main.c b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_main.c
index 28476b982bab..36ba15fc9776 100644
--- a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_main.c
+++ b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_main.c
@@ -2599,7 +2599,14 @@ qlcnic_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 			 "Device does not support MSI interrupts\n");
 
 	if (qlcnic_82xx_check(adapter)) {
-		qlcnic_dcb_enable(adapter->dcb);
+		err = qlcnic_dcb_enable(adapter->dcb);
+		if (err) {
+			qlcnic_clear_dcb_ops(adapter->dcb);
+			adapter->dcb = NULL;
+			dev_err(&pdev->dev, "Failed to enable DCB\n");
+			goto err_out_free_hw;
+		}
+
 		qlcnic_dcb_get_info(adapter->dcb);
 		err = qlcnic_setup_intr(adapter);
 
-- 
2.25.1