goldfish driver: Missing get_user_pages ingoldfish_pipe_read_write()

From: Mathieu Desnoyers
Date: Thu Jun 27 2013 - 13:36:00 EST


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.

I see that this feature has been merged in Linux kernel 3.9, but the
FIXME is still there in 3.10-rc7. Any plans on fixing this ?

Thanks,

Mathieu

--
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com
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