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[173.164.112.133]) by smtp.gmail.com with ESMTPSA id r87sm5080416pfb.112.2017.07.31.16.51.45 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 31 Jul 2017 16:51:47 -0700 (PDT) From: Kees Cook To: Andrew Morton Cc: Kees Cook , Stephen Smalley , David Howells , "Eric W. Biederman" , John Johansen , "Serge E. Hallyn" , Paul Moore , 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 Subject: [PATCH v4 05/15] selinux: Refactor to remove bprm_secureexec hook Date: Mon, 31 Jul 2017 16:51:23 -0700 Message-Id: <1501545093-56634-6-git-send-email-keescook@chromium.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1501545093-56634-1-git-send-email-keescook@chromium.org> References: <1501545093-56634-1-git-send-email-keescook@chromium.org> Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: X-Virus-Scanned: ClamAV using ClamSMTP 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: Stephen Smalley Signed-off-by: Kees Cook Acked-by: Paul Moore Tested-by: Paul Moore Acked-by: Serge Hallyn Reviewed-by: James Morris Reviewed-by: Andy Lutomirski --- security/selinux/hooks.c | 24 +++++------------------- 1 file changed, 5 insertions(+), 19 deletions(-) diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index 5d4051541518..edbc1c76964e 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -2414,30 +2414,17 @@ 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) @@ -6152,7 +6139,6 @@ 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),