linux-kernel - Re: [PATCH] cxl: core-pmu: Fix the usage of uninitialized variable

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-prev] [day] [month] [year] [list]

Message-ID: <20241024103856.000031ed@Huawei.com>
Date: Thu, 24 Oct 2024 10:38:56 +0100
From: Jonathan Cameron <Jonathan.Cameron@...wei.com>
To: Zicheng Qu <quzicheng@...wei.com>
CC: <dave@...olabs.net>, <dave.jiang@...el.com>, <alison.schofield@...el.com>,
	<vishal.l.verma@...el.com>, <ira.weiny@...el.com>,
	<dan.j.williams@...el.com>, <linux-cxl@...r.kernel.org>,
	<linux-kernel@...r.kernel.org>, <tanghui20@...wei.com>,
	<zhangqiao22@...wei.com>, <judy.chenhui@...wei.com>
Subject: Re: [PATCH] cxl: core-pmu: Fix the usage of uninitialized variable

On Wed, 23 Oct 2024 10:56:10 +0000
Zicheng Qu <quzicheng@...wei.com> wrote:

> In the devm_cxl_pmu_add() function, the variable rc might be
> uninitialized before its first use 'if (rc) goto err', leading
> to undefined behavior since its value depends on the compiler.
> Currently, the switch statement is limited to the CXL_PMU_MEMDEV type.
> If additional types are introduced, it could lead to similar concerns.
> If the type range remains unchanged, using a switch case is unnecessary.
> To enhance code extensibility and stability, it is recommended to
> address this potential aspect.
> 
> Cc: stable@...r.kernel.org # v6.6+
> Fixes: 1ad3f701c399 ("cxl/pci: Find and register CXL PMU devices")

Not a fix, because this is only called for CXL_PMU_MEMDEV.
So drop stable and fixes tag as I don't see this as appropriate to
backport (unless I'm missing something!)

Reasonable to harden the code. These might turn up in other
types of device. Ports will be handled differently (part of the
portdrv rework that I need to get back to), but maybe someone
will put a CXL PMU on a type 2 device and call this function.

Jonathan
 

> Signed-off-by: Zicheng Qu <quzicheng@...wei.com>
> ---
>  drivers/cxl/core/pmu.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/cxl/core/pmu.c b/drivers/cxl/core/pmu.c
> index 5d8e06b0ba6e..2d12887c9915 100644
> --- a/drivers/cxl/core/pmu.c
> +++ b/drivers/cxl/core/pmu.c
> @@ -51,6 +51,9 @@ int devm_cxl_pmu_add(struct device *parent, struct cxl_pmu_regs *regs,
>  	case CXL_PMU_MEMDEV:
>  		rc = dev_set_name(dev, "pmu_mem%d.%d", assoc_id, index);
>  		break;
> +	default:
> +		rc = -EINVAL;
> +		break;
>  	}
>  	if (rc)
>  		goto err;