* to continually duplicate across every architecture.
*/
+#include <linux/capability.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/errno.h>
#include <linux/smp_lock.h>
#include <linux/ptrace.h>
#include <linux/security.h>
+#include <linux/signal.h>
#include <asm/pgtable.h>
#include <asm/uaccess.h>
*/
void __ptrace_link(task_t *child, task_t *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);
}
/*
*/
void __ptrace_unlink(task_t *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);
}
if (child->state == TASK_TRACED)
return ret;
}
+static int may_attach(struct task_struct *task)
+{
+ if (!task->mm)
+ return -EPERM;
+ if (((current->uid != task->euid) ||
+ (current->uid != task->suid) ||
+ (current->uid != task->uid) ||
+ (current->gid != task->egid) ||
+ (current->gid != task->sgid) ||
+ (current->gid != task->gid)) && !capable(CAP_SYS_PTRACE))
+ return -EPERM;
+ smp_rmb();
+ if (!task->mm->dumpable && !capable(CAP_SYS_PTRACE))
+ return -EPERM;
+
+ return security_ptrace(current, task);
+}
+
+int ptrace_may_attach(struct task_struct *task)
+{
+ int err;
+ task_lock(task);
+ err = may_attach(task);
+ task_unlock(task);
+ return !err;
+}
+
int ptrace_attach(struct task_struct *task)
{
int retval;
retval = -EPERM;
if (task->pid <= 1)
goto bad;
- if (task == current)
- goto bad;
- if (!task->mm)
- goto bad;
- if(((current->uid != task->euid) ||
- (current->uid != task->suid) ||
- (current->uid != task->uid) ||
- (current->gid != task->egid) ||
- (current->gid != task->sgid) ||
- (current->gid != task->gid)) && !capable(CAP_SYS_PTRACE))
- goto bad;
- rmb();
- if (!task->mm->dumpable && !capable(CAP_SYS_PTRACE))
+ if (task->tgid == current->tgid)
goto bad;
/* the same process cannot be attached many times */
if (task->ptrace & PT_PTRACED)
goto bad;
- retval = security_ptrace(current, task);
+ retval = may_attach(task);
if (retval)
goto bad;
return retval;
}
+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 ((unsigned long) data > _NSIG)
- return -EIO;
+ if (!valid_signal(data))
+ 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);
+ if (child->ptrace)
+ __ptrace_detach(child, data);
write_unlock_irq(&tasklist_lock);
return 0;
return ret;
}
+
+/**
+ * ptrace_traceme -- helper for PTRACE_TRACEME
+ *
+ * Performs checks and sets PT_PTRACED.
+ * Should be used by all ptrace implementations for PTRACE_TRACEME.
+ */
+int ptrace_traceme(void)
+{
+ int ret;
+
+ /*
+ * 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;
+}
+
+/**
+ * ptrace_get_task_struct -- grab a task struct reference for ptrace
+ * @pid: process id to grab a task_struct reference of
+ *
+ * This function is a helper for ptrace implementations. It checks
+ * permissions and then grabs a task struct for use of the actual
+ * ptrace implementation.
+ *
+ * Returns the task_struct for @pid or an ERR_PTR() on failure.
+ */
+struct task_struct *ptrace_get_task_struct(pid_t pid)
+{
+ struct task_struct *child;
+
+ /*
+ * Tracing init is not allowed.
+ */
+ if (pid == 1)
+ return ERR_PTR(-EPERM);
+
+ read_lock(&tasklist_lock);
+ child = find_task_by_pid(pid);
+ if (child)
+ get_task_struct(child);
+ read_unlock(&tasklist_lock);
+ if (!child)
+ return ERR_PTR(-ESRCH);
+ return child;
+}
+
+#ifndef __ARCH_SYS_PTRACE
+asmlinkage long sys_ptrace(long request, long pid, long addr, long data)
+{
+ struct task_struct *child;
+ long ret;
+
+ /*
+ * This lock_kernel fixes a subtle race with suid exec
+ */
+ lock_kernel();
+ if (request == PTRACE_TRACEME) {
+ ret = ptrace_traceme();
+ goto out;
+ }
+
+ child = ptrace_get_task_struct(pid);
+ if (IS_ERR(child)) {
+ ret = PTR_ERR(child);
+ goto out;
+ }
+
+ if (request == PTRACE_ATTACH) {
+ ret = ptrace_attach(child);
+ goto out_put_task_struct;
+ }
+
+ ret = ptrace_check_attach(child, request == PTRACE_KILL);
+ if (ret < 0)
+ goto out_put_task_struct;
+
+ ret = arch_ptrace(child, request, addr, data);
+ if (ret < 0)
+ goto out_put_task_struct;
+
+ out_put_task_struct:
+ put_task_struct(child);
+ out:
+ unlock_kernel();
+ return ret;
+}
+#endif /* __ARCH_SYS_PTRACE */