On Wed, Apr 28, 2021 at 7:52 AM Andy Lutomirski <luto@xxxxxxxxxx> wrote: > > On Wed, Apr 28, 2021 at 7:48 AM David Laight <David.Laight@xxxxxxxxxx> wrote: > > > > From: Yu-cheng Yu > > > Sent: 27 April 2021 21:47 > > > > > > Control-flow Enforcement (CET) is a new Intel processor feature that blocks > > > return/jump-oriented programming attacks. Details are in "Intel 64 and > > > IA-32 Architectures Software Developer's Manual" [1]. > > ... > > > > Does this feature require that 'binary blobs' for out of tree drivers > > be compiled by a version of gcc that adds the ENDBRA instructions? > > > > If enabled for userspace, what happens if an old .so is dynamically > > loaded? CET will be disabled by ld.so in this case. > > Or do all userspace programs and libraries have to have been compiled > > with the ENDBRA instructions? Correct. ld and ld.so check this. > If you believe that the userspace tooling for the legacy IBT table > actually works, then it should just work. Yu-cheng, etc: how well > tested is it? > Legacy IBT bitmap isn't unused since it doesn't cover legacy codes generated by legacy JITs. -- H.J.
