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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Colin Ian King <colin.king@canonical.com>,
        "David S. Miller" <davem@davemloft.net>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.0 038/137] qede: fix write to freed pointer error and double free of ptp
Date:   Wed, 15 May 2019 12:55:19 +0200
Message-Id: <20190515090656.150382406@linuxfoundation.org>
In-Reply-To: <20190515090651.633556783@linuxfoundation.org>
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[ Upstream commit 1dc2b3d65523780ed1972d446c76e62e13f3e8f5 ]

The err2 error return path calls qede_ptp_disable that cleans up
on an error and frees ptp. After this, the free'd ptp is dereferenced
when ptp->clock is set to NULL and the code falls-through to error
path err1 that frees ptp again.

Fix this by calling qede_ptp_disable and exiting via an error
return path that does not set ptp->clock or kfree ptp.

Addresses-Coverity: ("Write to pointer after free")
Fixes: 035744975aec ("qede: Add support for PTP resource locking.")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/ethernet/qlogic/qede/qede_ptp.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/qlogic/qede/qede_ptp.c b/drivers/net/ethernet/qlogic/qede/qede_ptp.c
index 5f3f42a253616..bddb2b5982dcf 100644
--- a/drivers/net/ethernet/qlogic/qede/qede_ptp.c
+++ b/drivers/net/ethernet/qlogic/qede/qede_ptp.c
@@ -490,18 +490,17 @@ int qede_ptp_enable(struct qede_dev *edev, bool init_tc)
 
 	ptp->clock = ptp_clock_register(&ptp->clock_info, &edev->pdev->dev);
 	if (IS_ERR(ptp->clock)) {
-		rc = -EINVAL;
 		DP_ERR(edev, "PTP clock registration failed\n");
+		qede_ptp_disable(edev);
+		rc = -EINVAL;
 		goto err2;
 	}
 
 	return 0;
 
-err2:
-	qede_ptp_disable(edev);
-	ptp->clock = NULL;
 err1:
 	kfree(ptp);
+err2:
 	edev->ptp = NULL;
 
 	return rc;
-- 
2.20.1