On Mon, 29 Mar 2021 at 21:07, Derrick McKee <derrick.mc...@gmail.com> wrote: > > Hi, > > I am running across a scenario where a PAC signed code pointer (using > pacia) sometimes does not successfully authenticate despite the signed > pointer and the salt used to sign the pointer are correctly given to a > autia instruction. Only one particular pointer fails, while others > are correctly authenticated. Unfortunately, I can't provide a simple > use case, because the behavior is part of a running kernel, and all > the pointers involved are kernel space pointers. An example of what I > am seeing (not guaranteeing correct assembly, just a gist): > > mov x9, 0xffff800009200000 > mov x10, 0x20001 > pacia x9, x10 // x9 contains 0xff90800009200000 > ... > mov x9, 0xff90800009200000 > mov x10 0x20001 > autia x9, x10 // x9 contains invalid pointer > > However, this same code with different pointer values correctly > authenticate. Is there something specific about the kernel and PAC > authentication that I am missing? Thanks.
cc'ing Richard, but I suspect you'll need to provide more detail... thanks -- PMM
