Messages in this thread Patch in this message | | | 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() |
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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);
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