selinux: remove ptrace_sid
This changes checks related to ptrace to get rid of the ptrace_sid tracking. It's good to disentangle the security model from the ptrace implementation internals. It's sufficient to check against the SID of the ptracer at the time a tracee attempts a transition. Signed-off-by: Roland McGrath <roland@redhat.com> Acked-by: Stephen Smalley <sds@tycho.nsa.gov> Signed-off-by: James Morris <jmorris@namei.org>
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@ -161,7 +161,7 @@ static int task_alloc_security(struct task_struct *task)
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if (!tsec)
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return -ENOMEM;
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tsec->osid = tsec->sid = tsec->ptrace_sid = SECINITSID_UNLABELED;
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tsec->osid = tsec->sid = SECINITSID_UNLABELED;
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task->security = tsec;
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return 0;
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@ -1671,19 +1671,13 @@ static inline u32 file_to_av(struct file *file)
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static int selinux_ptrace(struct task_struct *parent, struct task_struct *child)
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{
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struct task_security_struct *psec = parent->security;
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struct task_security_struct *csec = child->security;
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int rc;
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rc = secondary_ops->ptrace(parent,child);
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if (rc)
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return rc;
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rc = task_has_perm(parent, child, PROCESS__PTRACE);
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/* Save the SID of the tracing process for later use in apply_creds. */
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if (!(child->ptrace & PT_PTRACED) && !rc)
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csec->ptrace_sid = psec->sid;
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return rc;
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return task_has_perm(parent, child, PROCESS__PTRACE);
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}
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static int selinux_capget(struct task_struct *target, kernel_cap_t *effective,
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@ -1905,6 +1899,22 @@ static int selinux_vm_enough_memory(struct mm_struct *mm, long pages)
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return __vm_enough_memory(mm, pages, cap_sys_admin);
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}
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/**
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* task_tracer_task - return the task that is tracing the given task
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* @task: task to consider
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*
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* Returns NULL if noone is tracing @task, or the &struct task_struct
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* pointer to its tracer.
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*
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* Must be called under rcu_read_lock().
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*/
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static struct task_struct *task_tracer_task(struct task_struct *task)
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{
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if (task->ptrace & PT_PTRACED)
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return rcu_dereference(task->parent);
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return NULL;
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}
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/* binprm security operations */
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static int selinux_bprm_alloc_security(struct linux_binprm *bprm)
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@ -2151,14 +2161,27 @@ static void selinux_bprm_apply_creds(struct linux_binprm *bprm, int unsafe)
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/* Check for ptracing, and update the task SID if ok.
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Otherwise, leave SID unchanged and kill. */
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if (unsafe & (LSM_UNSAFE_PTRACE | LSM_UNSAFE_PTRACE_CAP)) {
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rc = avc_has_perm(tsec->ptrace_sid, sid,
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SECCLASS_PROCESS, PROCESS__PTRACE,
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NULL);
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struct task_struct *tracer;
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struct task_security_struct *sec;
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u32 ptsid = 0;
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rcu_read_lock();
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tracer = task_tracer_task(current);
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if (likely(tracer != NULL)) {
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sec = tracer->security;
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ptsid = sec->sid;
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}
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rcu_read_unlock();
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if (ptsid != 0) {
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rc = avc_has_perm(ptsid, sid, SECCLASS_PROCESS,
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PROCESS__PTRACE, NULL);
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if (rc) {
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bsec->unsafe = 1;
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return;
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}
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}
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}
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tsec->sid = sid;
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}
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}
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@ -3112,11 +3135,6 @@ static int selinux_task_alloc_security(struct task_struct *tsk)
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tsec2->keycreate_sid = tsec1->keycreate_sid;
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tsec2->sockcreate_sid = tsec1->sockcreate_sid;
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/* Retain ptracer SID across fork, if any.
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This will be reset by the ptrace hook upon any
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subsequent ptrace_attach operations. */
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tsec2->ptrace_sid = tsec1->ptrace_sid;
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return 0;
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}
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@ -5080,6 +5098,7 @@ static int selinux_setprocattr(struct task_struct *p,
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char *name, void *value, size_t size)
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{
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struct task_security_struct *tsec;
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struct task_struct *tracer;
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u32 sid = 0;
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int error;
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char *str = value;
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@ -5168,18 +5187,24 @@ static int selinux_setprocattr(struct task_struct *p,
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/* Check for ptracing, and update the task SID if ok.
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Otherwise, leave SID unchanged and fail. */
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task_lock(p);
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if (p->ptrace & PT_PTRACED) {
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error = avc_has_perm_noaudit(tsec->ptrace_sid, sid,
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rcu_read_lock();
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tracer = task_tracer_task(p);
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if (tracer != NULL) {
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struct task_security_struct *ptsec = tracer->security;
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u32 ptsid = ptsec->sid;
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rcu_read_unlock();
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error = avc_has_perm_noaudit(ptsid, sid,
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SECCLASS_PROCESS,
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PROCESS__PTRACE, 0, &avd);
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if (!error)
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tsec->sid = sid;
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task_unlock(p);
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avc_audit(tsec->ptrace_sid, sid, SECCLASS_PROCESS,
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avc_audit(ptsid, sid, SECCLASS_PROCESS,
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PROCESS__PTRACE, &avd, error, NULL);
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if (error)
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return error;
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} else {
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rcu_read_unlock();
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tsec->sid = sid;
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task_unlock(p);
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}
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@ -5653,5 +5678,3 @@ int selinux_disable(void)
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return 0;
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}
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#endif
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@ -34,7 +34,6 @@ struct task_security_struct {
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u32 create_sid; /* fscreate SID */
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u32 keycreate_sid; /* keycreate SID */
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u32 sockcreate_sid; /* fscreate SID */
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u32 ptrace_sid; /* SID of ptrace parent */
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};
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struct inode_security_struct {
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