From: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
Date: Thu, 22 Mar 2018 13:44:56 -0500
Subject: net/mlx5: Fix use-after-free
Patch-mainline: v4.17-rc1
Git-commit: 594619497f3d6d4b8d8440e6d380e8da9dcc9eeb
References: bsc#1103990 FATE#326006

_rule_ is being freed and then dereferenced by accessing rule->ctx

Fix this by copying the value returned by PTR_ERR(rule->ctx) into a local
variable for its safe use after freeing _rule_

Addresses-Coverity-ID: 1466041 ("Read from pointer after free")
Fixes: 05564d0ae075 ("net/mlx5: Add flow-steering commands for FPGA IPSec implementation")
Reviewed-by: Yuval Shaia <yuval.shaia@oracle.com>
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Acked-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/net/ethernet/mellanox/mlx5/core/fpga/ipsec.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/drivers/net/ethernet/mellanox/mlx5/core/fpga/ipsec.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/fpga/ipsec.c
@@ -1061,8 +1061,9 @@ static int fpga_ipsec_fs_create_fte(stru
 
 	rule->ctx = mlx5_fpga_ipsec_fs_create_sa_ctx(dev, fte, is_egress);
 	if (IS_ERR(rule->ctx)) {
+		int err = PTR_ERR(rule->ctx);
 		kfree(rule);
-		return PTR_ERR(rule->ctx);
+		return err;
 	}
 
 	rule->fte = fte;