On Fri, Jan 07, 2022 at 12:01:17PM +0000, Catalin Marinas wrote: > I think we can look at this from two angles: > > 1. Ignoring MDWE, should whoever does the original mmap() also honour > PROT_BTI? We do this for static binaries but, for consistency, should > we extend it to dynamic executable? > > 2. A 'simple' fix to allow MDWE together with BTI. Thinking about it, (1) is not that different from the kernel setting PROT_EXEC on the main executable when the dynamic loader could've done it as well. There is a case for making this more consistent: whoever does the mmap() should use the full attributes. Question for the toolchain people: would the compiler ever generate relocations in the main executable that the linker needs to resolve via an mprotect(READ|WRITE) followed by mprotect(READ|EXEC)? If yes, we'd better go for a proper MDWE implementation in the kernel. -- Catalin
