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| author | Stephen Smalley <sds@tycho.nsa.gov> | 2017-01-10 20:28:32 +0300 |
|---|---|---|
| committer | Paul Moore <paul@paul-moore.com> | 2017-01-12 19:10:57 +0300 |
| commit | 3a2f5a59a695a73e0cde9a61e0feae5fa730e936 (patch) | |
| tree | 058704d18e909a2c0b46356c74d3c1156c2206aa /security | |
| parent | b4ba35c75a0671a06b978b6386b54148efddf39f (diff) | |
| download | linux-3a2f5a59a695a73e0cde9a61e0feae5fa730e936.tar.xz | |
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 <yangshukui@huawei.com>
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Diffstat (limited to 'security')
| -rw-r--r-- | security/security.c | 6 | ||||
| -rw-r--r-- | security/selinux/hooks.c | 7 | ||||
| -rw-r--r-- | security/smack/smack_lsm.c | 20 |
3 files changed, 0 insertions, 33 deletions
diff --git a/security/security.c b/security/security.c index 32052f5c76b2..8c9fee59e60a 100644 --- a/security/security.c +++ b/security/security.c @@ -1025,11 +1025,6 @@ int security_task_kill(struct task_struct *p, struct siginfo *info, return call_int_hook(task_kill, 0, p, info, sig, secid); } -int security_task_wait(struct task_struct *p) -{ - return call_int_hook(task_wait, 0, p); -} - int security_task_prctl(int option, unsigned long arg2, unsigned long arg3, unsigned long arg4, unsigned long arg5) { @@ -1769,7 +1764,6 @@ struct security_hook_heads security_hook_heads = { .task_movememory = LIST_HEAD_INIT(security_hook_heads.task_movememory), .task_kill = LIST_HEAD_INIT(security_hook_heads.task_kill), - .task_wait = LIST_HEAD_INIT(security_hook_heads.task_wait), .task_prctl = LIST_HEAD_INIT(security_hook_heads.task_prctl), .task_to_inode = LIST_HEAD_INIT(security_hook_heads.task_to_inode), 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), diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c index 8da4a6b9ca4d..2166373ea5a4 100644 --- a/security/smack/smack_lsm.c +++ b/security/smack/smack_lsm.c @@ -2272,25 +2272,6 @@ static int smack_task_kill(struct task_struct *p, struct siginfo *info, } /** - * smack_task_wait - Smack access check for waiting - * @p: task to wait for - * - * Returns 0 - */ -static int smack_task_wait(struct task_struct *p) -{ - /* - * Allow the operation to succeed. - * Zombies are bad. - * In userless environments (e.g. phones) programs - * get marked with SMACK64EXEC and even if the parent - * and child shouldn't be talking the parent still - * may expect to know when the child exits. - */ - return 0; -} - -/** * smack_task_to_inode - copy task smack into the inode blob * @p: task to copy from * @inode: inode to copy to @@ -4658,7 +4639,6 @@ static struct security_hook_list smack_hooks[] = { LSM_HOOK_INIT(task_getscheduler, smack_task_getscheduler), LSM_HOOK_INIT(task_movememory, smack_task_movememory), LSM_HOOK_INIT(task_kill, smack_task_kill), - LSM_HOOK_INIT(task_wait, smack_task_wait), LSM_HOOK_INIT(task_to_inode, smack_task_to_inode), LSM_HOOK_INIT(ipc_permission, smack_ipc_permission), |