linux-kernel - [PATCH][next] clk: ti: check for null return in strrchr to avoid null dereferencing

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Message-Id: <20170726235627.9163-1-colin.king@canonical.com>
Date:   Thu, 27 Jul 2017 00:56:27 +0100
From:   Colin King <colin.king@...onical.com>
To:     Tero Kristo <t-kristo@...com>,
        Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...eaurora.org>,
        linux-omap@...r.kernel.org, linux-clk@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org
Subject: [PATCH][next] clk: ti: check for null return in strrchr to avoid null dereferencing

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

strrchr can potentially return a null so the following strlen on the
null pointer can cause a null dereference. Add a check to see if
the string postfix is not null before calling strlen.

Detected by CoverityScan, CID#1452039 ("Dereference null return")

Signed-off-by: Colin Ian King <colin.king@...onical.com>
---
 drivers/clk/ti/adpll.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/clk/ti/adpll.c b/drivers/clk/ti/adpll.c
index 255cafb18336..bd7cb9a413c9 100644
--- a/drivers/clk/ti/adpll.c
+++ b/drivers/clk/ti/adpll.c
@@ -222,7 +222,7 @@ static int ti_adpll_setup_clock(struct ti_adpll_data *d, struct clk *clock,
 
 	/* Separate con_id in format "pll040dcoclkldo" to fit MAX_CON_ID */
 	postfix = strrchr(name, '.');
-	if (strlen(postfix) > 1) {
+	if (postfix && strlen(postfix) > 1) {
 		if (strlen(postfix) > ADPLL_MAX_CON_ID)
 			dev_warn(d->dev, "clock %s con_id lookup may fail\n",
 				 name);
-- 
2.11.0