fpga: stratix10-soc: fix use-after-free on s10_init()

[ Upstream commit f5dd87326fefe42a4b1a4b1a1a695060c33a88d6 ]

The refcount of fw_np has already been decreased by of_find_matching_node()
so it shouldn't be used anymore.
This patch adds an of_node_get() before of_find_matching_node() to avoid
the use-after-free problem.

Fixes: e7eef1d7633a ("fpga: add intel stratix10 soc fpga manager driver")
Signed-off-by: Wen Yang <wen.yang99@zte.com.cn>
Cc: Alan Tull <atull@kernel.org>
Cc: Moritz Fischer <mdf@kernel.org>
Cc: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Cc: linux-fpga@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Reviewed-by: Moritz Fischer <mdf@kernel.org>
Reviewed-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Acked-by: Alan Tull <atull@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/fpga/stratix10-soc.c b/drivers/fpga/stratix10-soc.c
index 13851b3d1c565dc9e3878efc53474915b4eec9d3..215d33789c74739aedb410baa26f3501c35d3e24 100644 (file)
--- a/drivers/fpga/stratix10-soc.c
+++ b/drivers/fpga/stratix10-soc.c
@@ -507,12 +507,16 @@ static int __init s10_init(void)
        if (!fw_np)
                return -ENODEV;
 
+       of_node_get(fw_np);
        np = of_find_matching_node(fw_np, s10_of_match);
-       if (!np)
+       if (!np) {
+               of_node_put(fw_np);
                return -ENODEV;
+       }
 
        of_node_put(np);
        ret = of_platform_populate(fw_np, s10_of_match, NULL, NULL);
+       of_node_put(fw_np);
        if (ret)
                return ret;