Messages in this thread | | | Date | Tue, 12 May 2020 16:47:14 -0700 | From | Kees Cook <> | Subject | Re: [PATCH 3/5] exec: Remove recursion from search_binary_handler |
| |
On Tue, May 12, 2020 at 04:08:56PM -0700, Kees Cook wrote: > I'm nearly certain the answer is "yes", but I wonder if we should stop > for a moment and ask "does anything still use MISC_FMT_OPEN_BINARY ? It > looks like either "O" or "C" binfmt_misc registration flag. My installed > binfmts on Ubuntu don't use them... > > I'm currently pulling a list of all the packages in Debian than depend > on the binfmt-support package and checking their flags.
So, binfmt-support in Debian doesn't in _support_ MISC_FMT_OPEN_BINARY ("O"):
credentials = (binfmt->credentials && !strcmp (binfmt->credentials, "yes")) ? "C" : ""; preserve = (binfmt->preserve && !strcmp (binfmt->preserve, "yes")) ? "P" : ""; fix_binary = (binfmt->fix_binary && !strcmp (binfmt->fix_binary, "yes")) ? "F" : ""; ... regstring = xasprintf (":%s:%c:%s:%s:%s:%s:%s%s%s\n", name, type, binfmt->offset, binfmt->magic, binfmt->mask, interpreter, credentials, preserve, fix_binary);
However, "credentials" ("C") does imply MISC_FMT_OPEN_BINARY.
I looked at every Debian package using binfmt-support, and "only" qemu uses "credential".
And now I wonder if qemu actually uses the resulting AT_EXECFD ...
-- Kees Cook
| |