Re: git: 350ba9672a7f - main - unix: Set O_RESOLVE_BENEATH on fds transferred between jails
Date: Wed, 25 Jun 2025 08:56:59 UTC
On 24 Jun 2025, at 23:04, Mark Johnston wrote: > The branch main has been updated by markj: > > URL: > https://cgit.FreeBSD.org/src/commit/?id=350ba9672a7f4f16e30534a603df577dfd083b3f > > commit 350ba9672a7f4f16e30534a603df577dfd083b3f > Author: Mark Johnston <markj@FreeBSD.org> > AuthorDate: 2025-06-24 20:05:37 +0000 > Commit: Mark Johnston <markj@FreeBSD.org> > CommitDate: 2025-06-24 21:04:24 +0000 > > unix: Set O_RESOLVE_BENEATH on fds transferred between jails > > If a pair of jails with different filesystem roots is able to > exchange > SCM_RIGHTS messages (e.g., using a unix socket in a shared nullfs > mount), a process in one jail can open a directory outside of the > root > of the second jail and then pass the fd to that second jail, > allowing > the receiving process to escape the jail chroot. > > Address this using the new FD_RESOLVE_BENEATH flag. When > externalizing > an SCM_RIGHTS message into the receiving process, automatically > set this > flag on all new fds where a jail boundary is crossed. This > ensures that > the receiver cannot do more than access files underneath the > directory; > in particular, the received fd cannot be used to access vnodes not > accessible by the sender. > > PR: 262179 > Reviewed by: kib > MFC after: 3 weeks > Differential Revision: https://reviews.freebsd.org/D50371 > --- > sys/amd64/conf/SYZKALLER | 5 +++++ > sys/kern/uipc_usrreq.c | 31 +++++++++++++++++++++++-------- > 2 files changed, 28 insertions(+), 8 deletions(-) > > diff --git a/sys/amd64/conf/SYZKALLER b/sys/amd64/conf/SYZKALLER > new file mode 100644 > index 000000000000..965841313616 > --- /dev/null > +++ b/sys/amd64/conf/SYZKALLER > @@ -0,0 +1,5 @@ > +include GENERIC-KASAN > +ident SYZKALLER > + > +options COVERAGE > +options KCOV I think you didn’t intend to include this bit. (Although perhaps it should be committed in its own commit.) — Kristof