linux-kernel - [PATCH 1/6] rtc: 88pm860x: fix possible race condition

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-Id: <20200311223956.51352-1-alexandre.belloni@bootlin.com>
Date:   Wed, 11 Mar 2020 23:39:51 +0100
From:   Alexandre Belloni <alexandre.belloni@...tlin.com>
To:     Alessandro Zummo <a.zummo@...ertech.it>,
        Alexandre Belloni <alexandre.belloni@...tlin.com>
Cc:     linux-rtc@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH 1/6] rtc: 88pm860x: fix possible race condition

The RTC IRQ is requested before the struct rtc_device is allocated,
this may lead to a NULL pointer dereference in the IRQ handler.

To fix this issue, allocating the rtc_device struct before requesting
the RTC IRQ using devm_rtc_allocate_device, and use rtc_register_device
to register the RTC device.

Also remove the unnecessary error message as the core already prints the
info.

Signed-off-by: Alexandre Belloni <alexandre.belloni@...tlin.com>
---
 drivers/rtc/rtc-88pm860x.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/drivers/rtc/rtc-88pm860x.c b/drivers/rtc/rtc-88pm860x.c
index 4743b16a8d84..1526402e126b 100644
--- a/drivers/rtc/rtc-88pm860x.c
+++ b/drivers/rtc/rtc-88pm860x.c
@@ -336,6 +336,10 @@ static int pm860x_rtc_probe(struct platform_device *pdev)
 	info->dev = &pdev->dev;
 	dev_set_drvdata(&pdev->dev, info);
 
+	info->rtc_dev = devm_rtc_allocate_device(&pdev->dev);
+	if (IS_ERR(info->rtc_dev))
+		return PTR_ERR(info->rtc_dev);
+
 	ret = devm_request_threaded_irq(&pdev->dev, info->irq, NULL,
 					rtc_update_handler, IRQF_ONESHOT, "rtc",
 					info);
@@ -377,13 +381,11 @@ static int pm860x_rtc_probe(struct platform_device *pdev)
 		}
 	}
 
-	info->rtc_dev = devm_rtc_device_register(&pdev->dev, "88pm860x-rtc",
-					    &pm860x_rtc_ops, THIS_MODULE);
-	ret = PTR_ERR(info->rtc_dev);
-	if (IS_ERR(info->rtc_dev)) {
-		dev_err(&pdev->dev, "Failed to register RTC device: %d\n", ret);
+	info->rtc_dev->ops = &pm860x_rtc_ops;
+
+	ret = rtc_register_device(info->rtc_dev);
+	if (ret)
 		return ret;
-	}
 
 	/*
 	 * enable internal XO instead of internal 3.25MHz clock since it can
-- 
2.24.1