From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail203.messagelabs.com (mail203.messagelabs.com [216.82.254.243]) by kanga.kvack.org (Postfix) with ESMTP id 2FA0B6B004A for ; Thu, 2 Jun 2011 10:22:59 -0400 (EDT) Received: by eyd9 with SMTP id 9so414012eyd.14 for ; Thu, 02 Jun 2011 07:22:56 -0700 (PDT) Date: Thu, 2 Jun 2011 17:22:42 +0300 From: Maxin B John Subject: Re: [PATCH] mm: dmapool: fix possible use after free in dmam_pool_destroy() Message-ID: <20110602142242.GA4115@maxin> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Sender: owner-linux-mm@kvack.org List-ID: To: eike-kernel@sf-tec.de Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, akpm@linux-foundation.org, dima@android.com, willy@linux.intel.com, segooon@gmail.com, tj@kernel.org, jkosina@suse.cz, tglx@linutronix.de On Thu, Jun 2, 2011 at 12:47 PM, Rolf Eike Beer wrote: > Maxin B John wrote: >> "dma_pool_destroy(pool)" calls "kfree(pool)". The freed pointer >> "pool" is again passed as an argument to the function "devres_destroy()". >> This patch fixes the possible use after free. > > The pool itself is not used there, only the address where the pool > has been.This will only lead to any trouble if something else is allocated to > the same place and inserted into the devres list of the same device between > the dma_pool_destroy() and devres_destroy(). Thank you very much for explaining it in detail. > But I agree that this is bad style. But if you are going to change > this please also have a look at devm_iounmap() in lib/devres.c. Maybe also the > devm_*irq* functions need the same changes. As per your suggestion, I have made similar modifications for lib/devres.c and kernel/irq/devres.c CCed the maintainers of the respective files. Signed-off-by: Maxin B. John --- diff --git a/kernel/irq/devres.c b/kernel/irq/devres.c index 1ef4ffc..bd8e788 100644 --- a/kernel/irq/devres.c +++ b/kernel/irq/devres.c @@ -87,8 +87,8 @@ void devm_free_irq(struct device *dev, unsigned int irq, void *dev_id) { struct irq_devres match_data = { irq, dev_id }; - free_irq(irq, dev_id); WARN_ON(devres_destroy(dev, devm_irq_release, devm_irq_match, &match_data)); + free_irq(irq, dev_id); } EXPORT_SYMBOL(devm_free_irq); diff --git a/lib/devres.c b/lib/devres.c index 6efddf5..7c0e953 100644 --- a/lib/devres.c +++ b/lib/devres.c @@ -79,9 +79,9 @@ EXPORT_SYMBOL(devm_ioremap_nocache); */ void devm_iounmap(struct device *dev, void __iomem *addr) { - iounmap(addr); WARN_ON(devres_destroy(dev, devm_ioremap_release, devm_ioremap_match, (void *)addr)); + iounmap(addr); } EXPORT_SYMBOL(devm_iounmap); -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org