On Fri, Oct 06, 2023 at 02:07:16PM +0200, David Hildenbrand wrote: > On 07.09.23 22:24, Guilherme G. Piccoli wrote: > > Currently the kernel provides a symlink to the executable binary, in the > > form of procfs file exe_file (/proc/self/exe_file for example). But what > > happens in interpreted scenarios (like binfmt_misc) is that such link > > always points to the *interpreter*. For cases of Linux binary emulators, > > like FEX [0] for example, it's then necessary to somehow mask that and > > emulate the true binary path. > > I'm absolutely no expert on that, but I'm wondering if, instead of modifying > exe_file and adding an interpreter file, you'd want to leave exe_file alone > and instead provide an easier way to obtain the interpreted file. > > Can you maybe describe why modifying exe_file is desired (about which > consumers are we worrying? ) and what exactly FEX does to handle that (how > does it mask that?). > > So a bit more background on the challenges without this change would be > appreciated. Yeah, it sounds like you're dealing with a process that examines /proc/self/exe_file for itself only to find the binfmt_misc interpreter when it was run via binfmt_misc? What actually breaks? Or rather, why does the process to examine exe_file? I'm just trying to see if there are other solutions here that would avoid creating an ambiguous interface... -- Kees Cook
