linux-kernel - [PATCH] clk: vc5: Add memory check to prevent oops

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Message-Id: <20200630210155.459250-1-aford173@gmail.com>
Date:   Tue, 30 Jun 2020 16:01:54 -0500
From:   Adam Ford <aford173@...il.com>
To:     linux-clk@...r.kernel.org
Cc:     dan.carpenter@...cle.com, aford@...conembedded.com,
        Adam Ford <aford173@...il.com>,
        Marek Vasut <marek.vasut@...il.com>,
        Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...nel.org>, linux-kernel@...r.kernel.org
Subject: [PATCH] clk: vc5: Add memory check to prevent oops

When getting the names of the child nodes, kasprintf is used to
allocate memory which is used to create the string for the node
name.  Unfortunately, there is no memory check to determine
if this allocation fails, it may cause an error when trying
to get child node name.

This patch will check if the memory allocation fails, and returns
and -NOMEM error instead of blindly moving on.

Suggested-by: Dan Carpenter <dan.carpenter@...cle.com>
Signed-off-by: Adam Ford <aford173@...il.com>

diff --git a/drivers/clk/clk-versaclock5.c b/drivers/clk/clk-versaclock5.c
index 1d8ee4b8b1f5..29cdb38dc40b 100644
--- a/drivers/clk/clk-versaclock5.c
+++ b/drivers/clk/clk-versaclock5.c
@@ -789,10 +789,14 @@ static int vc5_get_output_config(struct i2c_client *client,
 	int ret = 0;
 
 	child_name = kasprintf(GFP_KERNEL, "OUT%d", clk_out->num + 1);
+	if (!child_name) {
+		ret = -ENOMEM;
+		goto output_error;
+	}
 	np_output = of_get_child_by_name(client->dev.of_node, child_name);
 	kfree(child_name);
 	if (!np_output)
-		goto output_done;
+		return 0;
 
 	ret = vc5_update_mode(np_output, clk_out);
 	if (ret)
@@ -813,7 +817,6 @@ static int vc5_get_output_config(struct i2c_client *client,
 
 	of_node_put(np_output);
 
-output_done:
 	return ret;
 }
 
-- 
2.25.1