On Mon, Dec 18, 2017 at 3:17 PM, Laura Abbott <labb...@redhat.com> wrote: > Hi, > > Fedora got a bug report https://bugzilla.redhat.com/show_bug.cgi?id=1525974 > of coredumps failing for systemd units. If systemd units segfault, no > core is produced. > > commit e37fdb785a5f95ecadf43b773c97f676500ac7b8 (refs/bisect/bad) > Author: Kees Cook <keesc...@chromium.org> > Date: Tue Jul 18 15:25:31 2017 -0700 > > exec: Use secureexec for setting dumpability > The examination of "current" to decide dumpability is wrong. This > was a > check of and euid/uid (or egid/gid) mismatch in the existing process, > not the newly created one. This appears to stretch back into even the > "history.git" tree. Luckily, dumpability is later set in commit_creds(). > In earlier kernel versions before creds existed, similar checks also > existed late in the exec flow, covering up the mistake as far back as I > could find. > Note that because the commit_creds() check examines differences of > euid, > uid, egid, gid, and capabilities between the old and new creds, it would > look like the setup_new_exec() dumpability test could be entirely > removed. > However, the secureexec test may cover a different set of tests > (specific > to the LSMs) than what commit_creds() checks for. So, fix this test to > use secureexec (the removed euid tests are redundant to the commoncap > secureexec checks now). > Cc: David Howells <dhowe...@redhat.com> > Signed-off-by: Kees Cook <keesc...@chromium.org> > Acked-by: Serge Hallyn <se...@hallyn.com> > Reviewed-by: James Morris <james.l.mor...@oracle.com> > > > This was still broken as of -rc3 although interestingly enough this worked > on my rawhide system. Any ideas?
Hmmm, interesting. So dumpability can't follow secureexec -- that seems like a bad state since secureexec represents a process with privilege... -Kees -- Kees Cook Pixel Security
