Messages in this thread | | | Date | Wed, 27 Oct 2021 14:17:30 +0100 | From | Mark Rutland <> | Subject | Re: [PATCH v5 00/15] x86: Add support for Clang CFI |
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On Wed, Oct 27, 2021 at 12:55:17PM +0000, David Laight wrote: > From: Mark Rutland > > Sent: 27 October 2021 13:05 > ... > > Taking a step back, it'd be nicer if we didn't have the jump-table shim > > at all, and had some SW landing pad (e.g. a NOP with some magic bytes) > > in the callees that the caller could check for. Then function pointers > > would remain callable in call cases, and we could explcitly add landing > > pads to asm to protect those. I *think* that's what the grsecurity folk > > do, but I could be mistaken. > > It doesn't need to be a 'landing pad'. > The 'magic value' could be at 'label - 8'.
Sure; I'd intended to mean the general case of something at some fixed offset from the entrypoint, either before or after, potentially but not necessarily inline in the executed instruction stream.
Mark.
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