Messages in this thread | | | Date | Mon, 6 Jun 2011 09:37:46 +0100 | Subject | Re: [PATCH] mm: dmapool: fix possible use after free in dmam_pool_destroy() | From | Maxin B John <> |
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Hi,
On Thu, Jun 2, 2011 at 3:22 PM, Maxin B John <maxin.john@gmail.com> wrote: > On Thu, Jun 2, 2011 at 12:47 PM, Rolf Eike Beer <eike-kernel@sf-tec.de> 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 <maxin.john@gmail.com> > --- > 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); >
Could you please let me know your thoughts on this patch ?
Best Regards, Maxin -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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