Messages in this thread | | | From | Kees Cook <> | Date | Wed, 21 Feb 2018 14:52:28 -0800 | Subject | Re: RANDSTRUCT structs need linux/compiler_types.h (Was: [nfsd4] potentially hardware breaking regression in 4.14-rc and 4.13.11) |
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On Wed, Feb 21, 2018 at 2:19 PM, Maciej S. Szmigiero <mail@maciej.szmigiero.name> wrote: > One can see that offsets used to access various members of struct path are > different, and also that the original file from step 3 contains an object > named "__randomize_layout". > > This is caused by a fact that the current version of nfs4xdr.c includes > linux/fs_struct.h as the very first included header which then includes > linux/path.h as the very first included header, which then defines > struct path, but without including any files on its own. > > This results in __randomize_layout tag at the end of struct path > definition being treated as a variable name (since linux/compiler-gcc.h > that defines it as a type attribute has not been included yet).
Oh, well done! That would explain the code offset I was seeing when the plugin on, but no-op, since the variable would still exist.
I'll play with Linus's suggestion and see what we get.
Thanks!
-Kees
-- Kees Cook Pixel Security
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