From 4f189988a0a5890db597ec48fc0e8b09922f290a Mon Sep 17 00:00:00 2001 From: Paul Moore Date: Thu, 15 May 2014 11:16:06 -0400 Subject: [PATCH] selinux: reject setexeccon() on MNT_NOSUID applications with -EACCES We presently prevent processes from using setexecon() to set the security label of exec()'d processes when NO_NEW_PRIVS is enabled by returning an error; however, we silently ignore setexeccon() when exec()'ing from a nosuid mounted filesystem. This patch makes things a bit more consistent by returning an error in the setexeccon()/nosuid case. Signed-off-by: Paul Moore Acked-by: Andy Lutomirski Acked-by: Stephen Smalley --- security/selinux/hooks.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index 889cf4c3c3fa..b03b0776955a 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -2123,11 +2123,13 @@ static int selinux_bprm_set_creds(struct linux_binprm *bprm) new_tsec->exec_sid = 0; /* - * Minimize confusion: if no_new_privs and a transition is - * explicitly requested, then fail the exec. + * Minimize confusion: if no_new_privs or nosuid and a + * transition is explicitly requested, then fail the exec. */ if (bprm->unsafe & LSM_UNSAFE_NO_NEW_PRIVS) return -EPERM; + if (bprm->file->f_path.mnt->mnt_flags & MNT_NOSUID) + return -EACCES; } else { /* Check for a default transition on this program. */ rc = security_transition_sid(old_tsec->sid, isec->sid,