Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933467AbdGTADh (ORCPT ); Wed, 19 Jul 2017 20:03:37 -0400 Received: from mail-lf0-f68.google.com ([209.85.215.68]:38338 "EHLO mail-lf0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932187AbdGTADc (ORCPT ); Wed, 19 Jul 2017 20:03:32 -0400 MIME-Version: 1.0 X-Originating-IP: [108.49.102.27] In-Reply-To: <1500416736-49829-5-git-send-email-keescook@chromium.org> References: <1500416736-49829-1-git-send-email-keescook@chromium.org> <1500416736-49829-5-git-send-email-keescook@chromium.org> From: Paul Moore Date: Wed, 19 Jul 2017 20:03:30 -0400 Message-ID: Subject: Re: [PATCH v3 04/15] selinux: Refactor to remove bprm_secureexec hook To: Kees Cook , Stephen Smalley Cc: Andrew Morton , David Howells , "Eric W. Biederman" , John Johansen , "Serge E. Hallyn" , Casey Schaufler , Tetsuo Handa , James Morris , Andy Lutomirski , Linus Torvalds , linux-fsdevel@vger.kernel.org, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3090 Lines: 79 On Tue, Jul 18, 2017 at 6:25 PM, Kees Cook wrote: > The SELinux bprm_secureexec hook can be merged with the bprm_set_creds > hook since it's dealing with the same information, and all of the details > are finalized during the first call to the bprm_set_creds hook via > prepare_binprm() (subsequent calls due to binfmt_script, etc, are ignored > via bprm->called_set_creds). > > Here, the test can just happen at the end of the bprm_set_creds hook, > and the bprm_secureexec hook can be dropped. > > Cc: Paul Moore > Cc: Stephen Smalley > Signed-off-by: Kees Cook > --- > security/selinux/hooks.c | 24 +++++------------------- > 1 file changed, 5 insertions(+), 19 deletions(-) This seems reasonable in the context of the other changes. Stephen just posted an AT_SECURE test for the selinux-testsuite on the SELinux mailing list, it would be nice to ensure that this patchset doesn't run afoul of that. Acked-by: Paul Moore > diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c > index 0f1450a06b02..18038f73a2f7 100644 > --- a/security/selinux/hooks.c > +++ b/security/selinux/hooks.c > @@ -2413,30 +2413,17 @@ static int selinux_bprm_set_creds(struct linux_binprm *bprm) > > /* Clear any possibly unsafe personality bits on exec: */ > bprm->per_clear |= PER_CLEAR_ON_SETID; > - } > - > - return 0; > -} > - > -static int selinux_bprm_secureexec(struct linux_binprm *bprm) > -{ > - const struct task_security_struct *tsec = current_security(); > - u32 sid, osid; > - int atsecure = 0; > - > - sid = tsec->sid; > - osid = tsec->osid; > > - if (osid != sid) { > /* Enable secure mode for SIDs transitions unless > the noatsecure permission is granted between > the two SIDs, i.e. ahp returns 0. */ > - atsecure = avc_has_perm(osid, sid, > - SECCLASS_PROCESS, > - PROCESS__NOATSECURE, NULL); > + rc = avc_has_perm(old_tsec->sid, new_tsec->sid, > + SECCLASS_PROCESS, PROCESS__NOATSECURE, > + NULL); > + bprm->secureexec |= !!rc; > } > > - return !!atsecure; > + return 0; > } > > static int match_file(const void *p, struct file *file, unsigned fd) > @@ -6151,7 +6138,6 @@ static struct security_hook_list selinux_hooks[] __lsm_ro_after_init = { > LSM_HOOK_INIT(bprm_set_creds, selinux_bprm_set_creds), > LSM_HOOK_INIT(bprm_committing_creds, selinux_bprm_committing_creds), > LSM_HOOK_INIT(bprm_committed_creds, selinux_bprm_committed_creds), > - LSM_HOOK_INIT(bprm_secureexec, selinux_bprm_secureexec), > > LSM_HOOK_INIT(sb_alloc_security, selinux_sb_alloc_security), > LSM_HOOK_INIT(sb_free_security, selinux_sb_free_security), > -- > 2.7.4 -- paul moore www.paul-moore.com