From 3a2f5a59a695a73e0cde9a61e0feae5fa730e936 Mon Sep 17 00:00:00 2001 From: Stephen Smalley Date: Tue, 10 Jan 2017 12:28:32 -0500 Subject: security,selinux,smack: kill security_task_wait hook As reported by yangshukui, a permission denial from security_task_wait() can lead to a soft lockup in zap_pid_ns_processes() since it only expects sys_wait4() to return 0 or -ECHILD. Further, security_task_wait() can in general lead to zombies; in the absence of some way to automatically reparent a child process upon a denial, the hook is not useful. Remove the security hook and its implementations in SELinux and Smack. Smack already removed its check from its hook. Reported-by: yangshukui Signed-off-by: Stephen Smalley Acked-by: Casey Schaufler Acked-by: Oleg Nesterov Signed-off-by: Paul Moore --- security/selinux/hooks.c | 7 ------- 1 file changed, 7 deletions(-) (limited to 'security/selinux/hooks.c') diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index 55ad878f1146..a5398fea0966 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -3963,12 +3963,6 @@ static int selinux_task_kill(struct task_struct *p, struct siginfo *info, return avc_has_perm(secid, task_sid(p), SECCLASS_PROCESS, perm, NULL); } -static int selinux_task_wait(struct task_struct *p) -{ - return avc_has_perm(task_sid(p), current_sid(), SECCLASS_PROCESS, - PROCESS__SIGCHLD, NULL); -} - static void selinux_task_to_inode(struct task_struct *p, struct inode *inode) { @@ -6211,7 +6205,6 @@ static struct security_hook_list selinux_hooks[] = { LSM_HOOK_INIT(task_getscheduler, selinux_task_getscheduler), LSM_HOOK_INIT(task_movememory, selinux_task_movememory), LSM_HOOK_INIT(task_kill, selinux_task_kill), - LSM_HOOK_INIT(task_wait, selinux_task_wait), LSM_HOOK_INIT(task_to_inode, selinux_task_to_inode), LSM_HOOK_INIT(ipc_permission, selinux_ipc_permission), -- cgit v1.2.3