Messages in this thread | | | Date | Mon, 09 Mar 2009 10:22:08 +0800 | From | Li Zefan <> | Subject | Re: [PATCH -v2] memdup_user(): introduce |
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>>> +EXPORT_SYMBOL(memdup_user); > > Hi, > > I like the general idea of this a lot; it will make things much less > error prone (and we can add some sanity checks on "len" to catch the > standard security holes around copy_from_user usage). I'd even also > want a memdup_array() like thing in the style of calloc(). > > However, I have two questions/suggestions for improvement: > > I would like to question the use of the gfp argument here; > copy_from_user sleeps, so you can't use GFP_ATOMIC anyway. > You can't use GFP_NOFS etc, because the pagefault path will happily do > things that are equivalent, if not identical, to GFP_KERNEL. > > So the only value you can pass in correctly, as far as I can see, is > GFP_KERNEL. Am I wrong? >
Right! I just dug and found a few kmalloc(GFP_ATOMIC/GFP_NOFS)+copy_from_user(), so we have one more reason to use this memdup_user().
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