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Re: Do we want to add -fsanitize=function?


On 1/14/20 1:59 PM, Jakub Jelinek wrote:
On Tue, Jan 14, 2020 at 01:57:47PM +0100, Martin Liška wrote:
seems to be what they emit on x86_64.  Now, wonder what they do on other
targets

Other targets are not supported :P

, and how does it play with all the other options that add stuff
to the start of functions, e.g. -fcf-protection=full (where it needs to
really start with endbr64 instruction)

Using the options one will get:

_Z4savev:                               # @_Z4savev
	.cfi_startproc
	.long	846595819               # 0x327606eb
	.long	.L__unnamed_2-_Z4savev
# %bb.0:
	endbr64

So endbr64 is placed after the RTTI record.

Which is wrong, this will then fail on CET hardware.

Sure, which is a minor limitation. FCF is supposed to be production
security feature while UBSAN is more for a testing playground.

Martin


	Jakub



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