Re: [kernel-hardening] [PATCH] add the option of fortified string.h functions

On 09/05/17 03:57, Daniel Axtens wrote:

(ppc people: this does some compile and run time bounds checking on
string functions. It's cool - currently it picks up a lot of random
things so it will require some more work across the tree, but hopefully
it will eventually hit mainline.)

Ooh, nice!

I've tested this on ppc with pseries_le_defconfig.

I needed a couple of the fixes from github
(https://github.com/thestinger/linux-hardened/commits/4.11) in order to
build, specifically
https://github.com/thestinger/linux-hardened/commit/c65d6a6f309b06703584a23ac2b2bda4bb363143
https://github.com/thestinger/linux-hardened/commit/adcec4756574a8c7f7cb5b6fa51ebeaeeae71aae

Once those were added, I needed to disable fortification in prom_init.c,
as we apparently can't have new symbols there. (I don't understand that
file so I haven't dug into it.)

We also have problems with the feature fixup tests leading to a panic on
boot. It relates to getting what I think are asm labels(?) and how we
address them. I have just disabled fortify here for now; I think the
code could be rewritten to take the labels as unsigned char *, but I
haven't dug into it.

With the following fixups, I can boot a LE buildroot initrd (per
https://github.com/linuxppc/linux/wiki/Booting-with-Qemu). Sadly I don't
have access to real hardware any more, so I can't say anything more than
that. (ajd - perhaps relevant to your interests?)

I'll test it baremetal when I get the chance, and I'll see if I can 
investigate the issues you've raised.

-- 
Andrew Donnellan              OzLabs, ADL Canberra
andrew.donnellan@au1.ibm.com  IBM Australia Limited