[PATCH AUTOSEL 4.19 26/81] qede: fix write to free'd pointer error and double free of ptp

Sasha Levin
2019-05-07T05:59:35Z

From: Colin Ian King <colin.king@canonical.com>

[ 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 013ff567283c..5e574c3b625e 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