SELinux: clear parent death signal on SID transitions

Clear parent death signal on SID transitions to prevent unauthorized
signaling between SIDs.

Signed-off-by:  Stephen Smalley <sds@tycho.nsa.gov>
Acked-by: Eric Paris <eparis@parisplace.org>
Signed-off-by: James Morris <jmorris@localhost.localdomain>

diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index d8bc4172819c96bcefc49d69bf42f6619d6e4f04..36946629b6cafa391baa7168e55a8aab2bef3b78 100644 (file)
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -1907,6 +1907,9 @@ static void selinux_bprm_post_apply_creds(struct linux_binprm *bprm)
                spin_unlock_irq(&current->sighand->siglock);
        }
 
+       /* Always clear parent death signal on SID transitions. */
+       current->pdeath_signal = 0;
+
        /* Check whether the new SID can inherit resource limits
           from the old SID.  If not, reset all soft limits to
           the lower of the current task's hard limit and the init