linux-kernel - [PATCH] of: property: Add missing of_node_get() in parse

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Date:   Tue, 28 Feb 2023 18:40:19 +0100
From:   Jean-Jacques Hiblot <jjhiblot@...phandler.com>
To:     <robh+dt@...nel.org>, <frowand.list@...il.com>,
        <saravanak@...gle.com>
CC:     <gregkh@...uxfoundation.org>, <devicetree@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>,
        Jean Jacques Hiblot <jjhiblot@...phandler.com>
Subject: [PATCH] of: property: Add missing of_node_get() in parse_interrupt()

From: Jean Jacques Hiblot <jjhiblot@...phandler.com>

As all the other parsers do, parse_interrupt() must increase the refcount
of the device_node. Otherwise the refcount is decremented every time
parse_interrupt() is called on this node, leading to a potential
use-after-free.

This is a regression introduced by commit f265f06af194 ("of: property:
Fix fw_devlink handling of interrupts/interrupts-extended"). The reason is
that of_irq_parse_one() does not increase the refcount while the previously
used of_irq_find_parent() does.

Fixes: f265f06af194 ("of: property: Fix fw_devlink handling of interrupts/interrupts-extended")
Signed-off-by: Jean Jacques Hiblot <jjhiblot@...phandler.com>
---
 drivers/of/property.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/of/property.c b/drivers/of/property.c
index 134cfc980b70b..1f23bcb765c4e 100644
--- a/drivers/of/property.c
+++ b/drivers/of/property.c
@@ -1380,7 +1380,10 @@ static struct device_node *parse_interrupts(struct device_node *np,
 	    strcmp(prop_name, "interrupts-extended"))
 		return NULL;
 
-	return of_irq_parse_one(np, index, &sup_args) ? NULL : sup_args.np;
+	if (of_irq_parse_one(np, index, &sup_args))
+		return NULL;
+
+	return of_node_get(sup_args.np);
 }
 
 static const struct supplier_bindings of_supplier_bindings[] = {
-- 
2.25.1