[SSSD] Review of umask() in SSSD

Jakub Hrozek jhrozek at redhat.com
Thu Nov 5 11:58:33 UTC 2015


On Thu, Nov 05, 2015 at 12:22:00PM +0100, Petr Cech wrote:
> On 10/21/2015 03:19 PM, Petr Cech wrote:
> >On 10/12/2015 11:37 AM, Jakub Hrozek wrote:
> >>>> From a15acee2495ee12190e711f3344e14c54fc73062 Mon Sep 17 00:00:00 2001
> >>>>From: Petr Cech<pcech at redhat.com>
> >>>>Date: Wed, 7 Oct 2015 08:57:15 -0400
> >>>>Subject: [PATCH 10/11] KRB5_CHILD: More restrictive umask
> >>>>
> >>>>We could use more restrictive umask in krb5_child. I found out that
> >>>>there is directory creation, but it is done by create_ccache_dir()
> >>>>which has its own umask setup.
> >>>>
> >>>>Resolves:
> >>>>https://fedorahosted.org/sssd/ticket/2424
> >>>>---
> >>>>  src/providers/krb5/krb5_child.c | 2 +-
> >>>>  1 file changed, 1 insertion(+), 1 deletion(-)
> >>>>
> >>>>diff --git a/src/providers/krb5/krb5_child.c
> >>>b/src/providers/krb5/krb5_child.c
> >>>>index
> >>>69b7687188c04498f6ef7c10a1b5ca602daca8ef..be8db23df4660adcb59fcd2677b28ee415cd18d8
> >>>100644
> >>>>--- a/src/providers/krb5/krb5_child.c
> >>>>+++ b/src/providers/krb5/krb5_child.c
> >>>>@@ -720,7 +720,7 @@ static krb5_error_code create_ccache(char
> >>>*ccname, krb5_creds *creds)
> >>>>  #endif
> >>>>
> >>>>      /* Set a restrictive umask, just in case we end up creating
> >>>any file */
> >>>>-    umask(SSS_DFL_X_UMASK);
> >>>>+    umask(SSS_DFL_UMASK);
> >>I think this change is OK, as you say, the directories might need the
> >>executable flag, but then the directory-creating code should make sure
> >>the permissions are more relaxed..
> >I checked it again. It is OK.
> >
> >>
> >>btw I tested both FILE ccache:
> >>     krb5_ccname_template =FILE:/tmp/ccache_%p.XXXXXX
> >>the result looked OK to me:
> >>     # ll /tmp/ccache_admin at IPA.TEST.KDaxgn
> >>     -rw-------. 1 admin admins 1041 Oct 12 09:14
> >>/tmp/ccache_admin at IPA.TEST.KDaxgn
> >>and DIR ccache:
> >>     krb5_ccname_template = DIR:/tmp/ccaches/ccache_%p
> >>also looked good:
> >>     # ll -d/tmp/ccaches/
> >>     drwx------. 3 admin admins 4096 Oct 12 09:31/tmp/ccaches/
> >>     # ll -d/tmp/ccaches/ccache_admin at IPA.TEST/
> >>     drwx------. 2 admin admins 4096 Oct 12
> >>09:31/tmp/ccaches/ccache_admin at IPA.TEST/
> >>     # ll /tmp/ccaches/ccache_admin at IPA.TEST
> >>     -rw-------. 1 admin admins   10 Oct 12 09:31 primary
> >>     -rw-------. 1 admin admins 1041 Oct 12 09:31 tktrg2WYD
> >>
> >>>>
> >>>>      /* we create a new context here as the main process one may
> >>>have been
> >>>>       * opened as root and contain possibly references (even open
> >>>handles ?)
> >>>>--
> >>>>2.4.3
> >>>>
> >>>> From 6085c5ce86e6ba79f29d2c18f6fceca9bab5cecb Mon Sep 17 00:00:00 2001
> >>>>From: Petr Cech<pcech at redhat.com>
> >>>>Date: Wed, 7 Oct 2015 09:32:12 -0400
> >>>>Subject: [PATCH 11/11] UTILS: Removing SSS_DFL_X UMASK constant
> >>077 is still used in sss_unique_file(). So we can either use SSS_DFL_X
> >>umask there or convert to non-executable umask. Either way, I think it's
> >>OK to keep SSS_DFL_X even though it's unused right now for later use.
> >>It's just a constant.
> >OK, SSS_DFL_X_UMASK is still here, but not used in code.
> >
> >>
> >>sss_unique_file is used to generate kdcinfo files, where non-x would be
> >>OK because later we fchmod to 644 anyway:
> >>      ret = fchmod(fd, S_IRUSR|S_IWUSR|S_IRGRP|S_IROTH);
> >>
> >>..and also used in gpo_cache_store_file() which uses the same pattern..
> >>
> >I rewrote DFL_X to DFL in sss_unique_file().
> >
> >>...then also in sss_unique_filename() which is used to create dummy
> >>keytabs in ipa_server_trusted_dom_setup_1way(), handle_randomized() and
> >>ldap_child_get_tgt_sync(). Now:
> >>     - ipa_server_trusted_dom_setup_1way() - safe to change, we only
> >>use it
> >>     to get a unique filename, the contents are filled with ipa-getkeytab
> >>     - handle_randomized() - safe to change, libkrb5 unlinks the unique
> >>       file later, so we just really need the filename
> >>     - ldap_child_get_tgt_sync() - ditto, only used as input for
> >>       krb5_cc_resolve()
> >
> >The third patch is about redudant constant.
> >
> >And at the end, there are may uses of umask() in CI tests, which I leave
> >how they are. They could be test relevant. Maybe I will touch it in some
> >future patch.
> >
> >The last umask like constant is 644, which is connected to chmod(),
> >open(), etc. Do we want to have a constant for it?
> >
> >Regards
> >
> >Petr
> >
> >
> >_______________________________________________
> >sssd-devel mailing list
> >sssd-devel at lists.fedorahosted.org
> >https://lists.fedorahosted.org/mailman/listinfo/sssd-devel
> >
> bump

I was reviewing the patches this morning :-)

ACK

CI: http://sssd-ci.duckdns.org/logs/job/32/08/summary.html


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