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>
Signed-off-by: Adrian Bunk <bunk@kernel.org>

diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index b65c201e9ff50386ea6cb43ed2c0c91f63a4cfe7..d66485f863b2ddfd5ddeb24953659dce6a60f5cc 100644 (file)
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -1740,6 +1740,9 @@ 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