linux-kernel - Re: [PATCH] serial: 8250_lpss: Fix missing check for return value of pci_get

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

Message-ID: <ZInmEJJjLEwCiOBU@smile.fi.intel.com>
Date:   Wed, 14 Jun 2023 19:08:48 +0300
From:   Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:     Chenyuan Mi <cymi20@...an.edu.cn>
Cc:     ilpo.jarvinen@...ux.intel.com, gregkh@...uxfoundation.org,
        jirislaby@...nel.org, linux-serial@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] serial: 8250_lpss: Fix missing check for return value of
 pci_get_slot()

On Wed, Jun 14, 2023 at 08:32:26AM -0700, Chenyuan Mi wrote:
> The pci_get_slot() function may return NULL, which may
> cause null pointer deference, and most other callsites of
> pci_get_slot() do Null check. Add Null check for return
> value of pci_get_slot().
> 
> Found by our static analysis tool.

...

>  	dma_dev = pci_get_slot(pdev->bus, PCI_DEVFN(PCI_SLOT(pdev->devfn), 0));
> +	if (!dma_dev)
> +		return -ENODEV;

This adds (almost) a dead code. The function 0 must be present in accordance
with the PCI specification (even earliest version of it state that).
If pci_get_slot() returns a NULL, in this case it means that something, much
bigger issue, happens and this check won't help us to do anything anyway.

-- 
With Best Regards,
Andy Shevchenko