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Groups > linux.kernel > #1315834
| From | Jann Horn <jann@thejh.net> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [kernel-hardening] Re: [PATCH 1/2] sysctl: expand use of proc_dointvec_minmax_sysadmin |
| Date | 2016-01-24 07:40 +0100 |
| Message-ID | <qUmv8-PM-3@gated-at.bofh.it> (permalink) |
| References | (3 earlier) <qUeQV-3GP-1@gated-at.bofh.it> <qUhON-5Q5-9@gated-at.bofh.it> <qUhYt-5To-1@gated-at.bofh.it> <qUi8a-5WE-5@gated-at.bofh.it> <qUmbL-Hp-11@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
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On Sun, Jan 24, 2016 at 12:02:41AM -0600, Eric W. Biederman wrote: > Jann Horn <jann@thejh.net> writes: > > > On Sun, Jan 24, 2016 at 01:43:42AM +0000, Al Viro wrote: > >> On Sat, Jan 23, 2016 at 07:20:17PM -0600, Eric W. Biederman wrote: > >> > >> > Yep. That is about the size of it. file * used to be passed to the > >> > sysctl methods but it was removed several years ago because no one was > >> > using it. > >> > >> Generally cred would be better... > > > >> Alternatively we could eat one more > >> pointer in task_struct and stash a reference to that sucker there, rather > >> than adding an explicit argument (again, with cred instead of file). > >> Not sure... > > > > I think it makes sense to do this the same way as the rest of the VFS code > > here (which passes the creds down through an argument). > > > > And adding the arguments everywhere doesn't really mean more work - either > > way, someone should probably go through all of those sysctl handlers and > > fix them up to use the file creds. > > Not all of them need it. It might be worth figuring out the necessary > rigamarole to hook into sysctl_perm the way the networking code does and > have that require the capability at open time. > > The advantage is that open time is when it is actually appropraite to > check permissions. I could be wrong but I doubt there is enough madness > with the handful of sysctl users that call capable to require the checks > to happen on write and not on open. That would work - if all sysctls know whether a capability will be needed for writing later on and don't decide it based on the written data. Is that always true? Looking through some of the sysctl handlers, I found proc_do_uts_string and pid_ns_ctl_handler, which operate on a namespace looked up through current at write time. I think that's buggy and ought to be done using the file opener creds and on the file opener's namespaces, but where can those be stored?
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[PATCH 0/2] sysctl: allow CLONE_NEWUSER to be disabled Kees Cook <keescook@chromium.org> - 2016-01-22 23:40 +0100
[PATCH 1/2] sysctl: expand use of proc_dointvec_minmax_sysadmin Kees Cook <keescook@chromium.org> - 2016-01-22 23:40 +0100
Re: [PATCH 1/2] sysctl: expand use of proc_dointvec_minmax_sysadmin ebiederm@xmission.com (Eric W. Biederman) - 2016-01-23 04:30 +0100
Re: [kernel-hardening] Re: [PATCH 1/2] sysctl: expand use of proc_dointvec_minmax_sysadmin Jann Horn <jann@thejh.net> - 2016-01-23 23:30 +0100
Re: [kernel-hardening] Re: [PATCH 1/2] sysctl: expand use of proc_dointvec_minmax_sysadmin ebiederm@xmission.com (Eric W. Biederman) - 2016-01-24 02:40 +0100
Re: [kernel-hardening] Re: [PATCH 1/2] sysctl: expand use of proc_dointvec_minmax_sysadmin Al Viro <viro@ZenIV.linux.org.uk> - 2016-01-24 02:50 +0100
Re: [kernel-hardening] Re: [PATCH 1/2] sysctl: expand use of proc_dointvec_minmax_sysadmin Jann Horn <jann@thejh.net> - 2016-01-24 03:00 +0100
Re: [kernel-hardening] Re: [PATCH 1/2] sysctl: expand use of proc_dointvec_minmax_sysadmin ebiederm@xmission.com (Eric W. Biederman) - 2016-01-24 07:20 +0100
Re: [kernel-hardening] Re: [PATCH 1/2] sysctl: expand use of proc_dointvec_minmax_sysadmin Jann Horn <jann@thejh.net> - 2016-01-24 07:40 +0100
Re: [kernel-hardening] Re: [PATCH 1/2] sysctl: expand use of proc_dointvec_minmax_sysadmin ebiederm@xmission.com (Eric W. Biederman) - 2016-01-24 08:00 +0100
Re: [PATCH 0/2] sysctl: allow CLONE_NEWUSER to be disabled Richard Weinberger <richard@nod.at> - 2016-01-22 23:50 +0100
Re: [PATCH 0/2] sysctl: allow CLONE_NEWUSER to be disabled ebiederm@xmission.com (Eric W. Biederman) - 2016-01-23 04:20 +0100
Re: [PATCH 0/2] sysctl: allow CLONE_NEWUSER to be disabled Kees Cook <keescook@chromium.org> - 2016-01-24 22:00 +0100
Re: [kernel-hardening] Re: [PATCH 0/2] sysctl: allow CLONE_NEWUSER to be disabled Serge Hallyn <serge.hallyn@ubuntu.com> - 2016-01-26 08:40 +0100
Re: [PATCH 0/2] sysctl: allow CLONE_NEWUSER to be disabled Andy Lutomirski <luto@amacapital.net> - 2016-01-24 23:30 +0100
Re: [PATCH 0/2] sysctl: allow CLONE_NEWUSER to be disabled Kees Cook <keescook@chromium.org> - 2016-01-25 20:00 +0100
Re: [PATCH 0/2] sysctl: allow CLONE_NEWUSER to be disabled ebiederm@xmission.com (Eric W. Biederman) - 2016-01-25 21:00 +0100
Re: [PATCH 0/2] sysctl: allow CLONE_NEWUSER to be disabled Kees Cook <keescook@chromium.org> - 2016-01-25 23:40 +0100
Re: [PATCH 0/2] sysctl: allow CLONE_NEWUSER to be disabled Andy Lutomirski <luto@amacapital.net> - 2016-01-26 00:40 +0100
Re: [kernel-hardening] Re: [PATCH 0/2] sysctl: allow CLONE_NEWUSER to be disabled Daniel Micay <danielmicay@gmail.com> - 2016-01-26 03:30 +0100
Re: [PATCH 0/2] sysctl: allow CLONE_NEWUSER to be disabled ebiederm@xmission.com (Eric W. Biederman) - 2016-01-26 06:10 +0100
Re: [PATCH 0/2] sysctl: allow CLONE_NEWUSER to be disabled Josh Boyer <jwboyer@fedoraproject.org> - 2016-01-26 15:40 +0100
Re: [PATCH 0/2] sysctl: allow CLONE_NEWUSER to be disabled "Austin S. Hemmelgarn" <ahferroin7@gmail.com> - 2016-01-26 15:50 +0100
Re: [PATCH 0/2] sysctl: allow CLONE_NEWUSER to be disabled Josh Boyer <jwboyer@fedoraproject.org> - 2016-01-26 16:00 +0100
Re: [kernel-hardening] Re: [PATCH 0/2] sysctl: allow CLONE_NEWUSER to be disabled Serge Hallyn <serge.hallyn@ubuntu.com> - 2016-01-26 18:30 +0100
Re: [kernel-hardening] Re: [PATCH 0/2] sysctl: allow CLONE_NEWUSER to be disabled Josh Boyer <jwboyer@fedoraproject.org> - 2016-01-26 21:00 +0100
Re: [kernel-hardening] Re: [PATCH 0/2] sysctl: allow CLONE_NEWUSER to be disabled "Austin S. Hemmelgarn" <ahferroin7@gmail.com> - 2016-01-26 21:20 +0100
Re: [kernel-hardening] Re: [PATCH 0/2] sysctl: allow CLONE_NEWUSER to be disabled Serge Hallyn <serge.hallyn@ubuntu.com> - 2016-01-26 18:20 +0100
Re: [kernel-hardening] Re: [PATCH 0/2] sysctl: allow CLONE_NEWUSER to be disabled "Austin S. Hemmelgarn" <ahferroin7@gmail.com> - 2016-01-26 19:20 +0100
Re: [kernel-hardening] Re: [PATCH 0/2] sysctl: allow CLONE_NEWUSER to be disabled Andy Lutomirski <luto@amacapital.net> - 2016-01-26 19:30 +0100
Re: [kernel-hardening] Re: [PATCH 0/2] sysctl: allow CLONE_NEWUSER to be disabled "Austin S. Hemmelgarn" <ahferroin7@gmail.com> - 2016-01-26 19:50 +0100
Re: [kernel-hardening] Re: [PATCH 0/2] sysctl: allow CLONE_NEWUSER to be disabled Kees Cook <keescook@chromium.org> - 2016-01-27 00:20 +0100
Re: [kernel-hardening] Re: [PATCH 0/2] sysctl: allow CLONE_NEWUSER to be disabled Kees Cook <keescook@chromium.org> - 2016-01-27 00:20 +0100
Re: [kernel-hardening] Re: [PATCH 0/2] sysctl: allow CLONE_NEWUSER to be disabled ebiederm@xmission.com (Eric W. Biederman) - 2016-01-27 11:50 +0100
Re: [kernel-hardening] Re: [PATCH 0/2] sysctl: allow CLONE_NEWUSER to be disabled "Austin S. Hemmelgarn" <ahferroin7@gmail.com> - 2016-01-27 13:40 +0100
Re: [PATCH 0/2] sysctl: allow CLONE_NEWUSER to be disabled Kees Cook <keescook@chromium.org> - 2016-01-26 17:40 +0100
Re: [PATCH 0/2] sysctl: allow CLONE_NEWUSER to be disabled Kees Cook <keescook@chromium.org> - 2016-01-25 20:00 +0100
Re: [PATCH 0/2] sysctl: allow CLONE_NEWUSER to be disabled Andy Lutomirski <luto@amacapital.net> - 2016-01-25 20:00 +0100
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