* to continually duplicate across every architecture.
*/
+#include <linux/capability.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/errno.h>
*
* Must be called with the tasklist lock write-held.
*/
-void __ptrace_link(task_t *child, task_t *new_parent)
+void __ptrace_link(struct task_struct *child, struct task_struct *new_parent)
{
- if (!list_empty(&child->ptrace_list))
- BUG();
+ BUG_ON(!list_empty(&child->ptrace_list));
if (child->parent == new_parent)
return;
list_add(&child->ptrace_list, &child->parent->ptrace_children);
- REMOVE_LINKS(child);
+ remove_parent(child);
child->parent = new_parent;
- SET_LINKS(child);
+ add_parent(child);
}
/*
* TASK_TRACED, resume it now.
* Requires that irqs be disabled.
*/
-void ptrace_untrace(task_t *child)
+void ptrace_untrace(struct task_struct *child)
{
spin_lock(&child->sighand->siglock);
if (child->state == TASK_TRACED) {
signal_wake_up(child, 1);
}
}
- if (child->signal->flags & SIGNAL_GROUP_EXIT) {
- sigaddset(&child->pending.signal, SIGKILL);
- signal_wake_up(child, 1);
- }
spin_unlock(&child->sighand->siglock);
}
*
* Must be called with the tasklist lock write-held.
*/
-void __ptrace_unlink(task_t *child)
+void __ptrace_unlink(struct task_struct *child)
{
- if (!child->ptrace)
- BUG();
+ BUG_ON(!child->ptrace);
+
child->ptrace = 0;
if (!list_empty(&child->ptrace_list)) {
list_del_init(&child->ptrace_list);
- REMOVE_LINKS(child);
+ remove_parent(child);
child->parent = child->real_parent;
- SET_LINKS(child);
+ add_parent(child);
}
- ptrace_untrace(child);
+ if (child->state == TASK_TRACED)
+ ptrace_untrace(child);
}
/*
static int may_attach(struct task_struct *task)
{
- if (!task->mm)
- return -EPERM;
+ /* May we inspect the given task?
+ * This check is used both for attaching with ptrace
+ * and for allowing access to sensitive information in /proc.
+ *
+ * ptrace_attach denies several cases that /proc allows
+ * because setting up the necessary parent/child relationship
+ * or halting the specified task is impossible.
+ */
+ int dumpable = 0;
+ /* Don't let security modules deny introspection */
+ if (task == current)
+ return 0;
if (((current->uid != task->euid) ||
(current->uid != task->suid) ||
(current->uid != task->uid) ||
(current->gid != task->gid)) && !capable(CAP_SYS_PTRACE))
return -EPERM;
smp_rmb();
- if (!task->mm->dumpable && !capable(CAP_SYS_PTRACE))
+ if (task->mm)
+ dumpable = task->mm->dumpable;
+ if (!dumpable && !capable(CAP_SYS_PTRACE))
return -EPERM;
return security_ptrace(current, task);
int ptrace_attach(struct task_struct *task)
{
int retval;
- task_lock(task);
+
retval = -EPERM;
if (task->pid <= 1)
- goto bad;
+ goto out;
if (task->tgid == current->tgid)
+ goto out;
+
+repeat:
+ /*
+ * Nasty, nasty.
+ *
+ * We want to hold both the task-lock and the
+ * tasklist_lock for writing at the same time.
+ * But that's against the rules (tasklist_lock
+ * is taken for reading by interrupts on other
+ * cpu's that may have task_lock).
+ */
+ task_lock(task);
+ local_irq_disable();
+ if (!write_trylock(&tasklist_lock)) {
+ local_irq_enable();
+ task_unlock(task);
+ do {
+ cpu_relax();
+ } while (!write_can_lock(&tasklist_lock));
+ goto repeat;
+ }
+
+ if (!task->mm)
goto bad;
/* the same process cannot be attached many times */
if (task->ptrace & PT_PTRACED)
? PT_ATTACHED : 0);
if (capable(CAP_SYS_PTRACE))
task->ptrace |= PT_PTRACE_CAP;
- task_unlock(task);
- write_lock_irq(&tasklist_lock);
__ptrace_link(task, current);
- write_unlock_irq(&tasklist_lock);
force_sig_specific(SIGSTOP, task);
- return 0;
bad:
+ write_unlock_irq(&tasklist_lock);
task_unlock(task);
+out:
return retval;
}
+static inline void __ptrace_detach(struct task_struct *child, unsigned int data)
+{
+ child->exit_code = data;
+ /* .. re-parent .. */
+ __ptrace_unlink(child);
+ /* .. and wake it up. */
+ if (child->exit_state != EXIT_ZOMBIE)
+ wake_up_process(child);
+}
+
int ptrace_detach(struct task_struct *child, unsigned int data)
{
if (!valid_signal(data))
- return -EIO;
+ return -EIO;
/* Architecture-specific hardware disable .. */
ptrace_disable(child);
- /* .. re-parent .. */
- child->exit_code = data;
-
write_lock_irq(&tasklist_lock);
- __ptrace_unlink(child);
- /* .. and wake it up. */
- if (child->exit_state != EXIT_ZOMBIE)
- wake_up_process(child);
+ /* protect against de_thread()->release_task() */
+ if (child->ptrace)
+ __ptrace_detach(child, data);
write_unlock_irq(&tasklist_lock);
return 0;
if (write) {
copy_to_user_page(vma, page, addr,
maddr + offset, buf, bytes);
- if (!PageCompound(page))
- set_page_dirty_lock(page);
+ set_page_dirty_lock(page);
} else {
copy_from_user_page(vma, page, addr,
buf, maddr + offset, bytes);
*/
int ptrace_traceme(void)
{
- int ret;
+ int ret = -EPERM;
/*
* Are we already being traced?
*/
- if (current->ptrace & PT_PTRACED)
- return -EPERM;
- ret = security_ptrace(current->parent, current);
- if (ret)
- return -EPERM;
- /*
- * Set the ptrace bit in the process ptrace flags.
- */
- current->ptrace |= PT_PTRACED;
- return 0;
+ task_lock(current);
+ if (!(current->ptrace & PT_PTRACED)) {
+ ret = security_ptrace(current->parent, current);
+ /*
+ * Set the ptrace bit in the process ptrace flags.
+ */
+ if (!ret)
+ current->ptrace |= PT_PTRACED;
+ }
+ task_unlock(current);
+ return ret;
}
/**
projects / powerpc.git / blobdiff