From ddb4a1442def2a78b91a85b4251fb712ef23662b Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Tue, 18 Jul 2017 15:25:23 -0700 Subject: exec: Rename bprm->cred_prepared to called_set_creds The cred_prepared bprm flag has a misleading name. It has nothing to do with the bprm_prepare_cred hook, and actually tracks if bprm_set_creds has been called. Rename this flag and improve its comment. Cc: David Howells Cc: Stephen Smalley Cc: Casey Schaufler Signed-off-by: Kees Cook Acked-by: John Johansen Acked-by: James Morris Acked-by: Paul Moore Acked-by: Serge Hallyn --- security/selinux/hooks.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'security/selinux') diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index 33fd061305c4..1db40195d178 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -2356,7 +2356,7 @@ static int selinux_bprm_set_creds(struct linux_binprm *bprm) /* SELinux context only depends on initial program or script and not * the script interpreter */ - if (bprm->cred_prepared) + if (bprm->called_set_creds) return 0; old_tsec = current_security(); -- cgit v1.2.3 From 62874c3adf709b884ceb0c61c35ab3794b3b0e95 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Tue, 18 Jul 2017 15:25:25 -0700 Subject: selinux: Refactor to remove bprm_secureexec hook 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(-) (limited to 'security/selinux') diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index 1db40195d178..a1f5f5ddfba7 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -2442,30 +2442,17 @@ 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) @@ -6266,7 +6253,6 @@ 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), -- cgit v1.2.3