Messages in this thread | | | Date | Thu, 10 Mar 2022 18:46:29 -0800 | Subject | Re: [PATCH v3 2/2] lkdtm: Add Shadow Call Stack tests | From | Dan Li <> |
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On 3/9/22 12:16, Kees Cook wrote: > On Mon, Mar 07, 2022 at 07:16:36AM -0800, Dan Li wrote: >> But currently it still crashes when I try to enable >> "-mbranch-protection=pac-ret+leaf+bti". >> >> Because the address of "&&redirected" is not encrypted under pac, >> the autiasp check will fail when set_return_addr returns, and >> eventually cause the function to crash when it returns to "&&redirected" >> ("&&redirected" as a reserved label always seems to start with a bti j >> insn). > > Strictly speaking, this is entirely correct. :) > >> For lkdtm, if we're going to handle both cases in one function, maybe >> it would be better to turn off the -mbranch-protection=pac-ret+leaf+bti >> and maybe also turn off -O2 options for the function :) > > If we can apply a function attribute to turn off pac for the "does this > work without protections", that should be sufficient. >
Got it, will do in the next version :)
Thanks, Dan.
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