Messages in this thread | | | Date | Thu, 27 Jun 2013 11:14:49 -0700 | From | Greg Kroah-Hartman <> | Subject | Re: goldfish driver: Missing get_user_pages in goldfish_pipe_read_write() |
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On Thu, Jun 27, 2013 at 02:03:44PM -0400, Mathieu Desnoyers wrote: > * Greg Kroah-Hartman (gregkh@linuxfoundation.org) wrote: > > On Thu, Jun 27, 2013 at 01:35:32PM -0400, Mathieu Desnoyers wrote: > > > The following code snippet: > > > > > > drivers/platform/goldfish/goldfish_pipe.c: > > > goldfish_pipe_read_write() > > > > > > /* Ensure that the corresponding page is properly mapped */ > > > /* FIXME: this isn't safe or sufficient - use get_user_pages */ > > > if (is_write) { > > > char c; > > > /* Ensure that the page is mapped and readable */ > > > if (__get_user(c, (char __user *)address)) { > > > if (!ret) > > > ret = -EFAULT; > > > break; > > > } > > > } else { > > > /* Ensure that the page is mapped and writable */ > > > if (__put_user(0, (char __user *)address)) { > > > if (!ret) > > > ret = -EFAULT; > > > break; > > > } > > > } > > > > > > Seems to lack the kind of validation required to make it fail properly > > > if the memory range is not fully populated. > > > > This is an emulated platform only, so it's probably not a big deal, > > right? > > You're probably right. As long as it is not configured and somehow still > accessible on a production device.
There is no device that could ever be "production" for this emulated hardware platform, unless a desktop system wants to "emulate" the android userspace system somehow. Then it could be "real", but even then, how would a user application get access to this codepath?
thanks,
greg k-h
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