#include <asm/pgtable.h>
#include <asm/uaccess.h>
+
+/*
+ * Initialize a new task whose father had been ptraced.
+ *
+ * Called from copy_process().
+ */
+void ptrace_fork(struct task_struct *child, unsigned long clone_flags)
+{
+ arch_ptrace_fork(child, clone_flags);
+}
+
/*
* ptrace a task: make the debugger its new parent and
* move it to the ptrace list.
*/
void __ptrace_link(struct task_struct *child, struct task_struct *new_parent)
{
- BUG_ON(!list_empty(&child->ptrace_list));
- if (child->parent == new_parent)
- return;
- list_add(&child->ptrace_list, &child->parent->ptrace_children);
- remove_parent(child);
+ BUG_ON(!list_empty(&child->ptrace_entry));
+ list_add(&child->ptrace_entry, &new_parent->ptraced);
child->parent = new_parent;
- add_parent(child);
}
/*
* TASK_TRACED, resume it now.
* Requires that irqs be disabled.
*/
-void ptrace_untrace(struct task_struct *child)
+static void ptrace_untrace(struct task_struct *child)
{
spin_lock(&child->sighand->siglock);
if (task_is_traced(child)) {
BUG_ON(!child->ptrace);
child->ptrace = 0;
- if (ptrace_reparented(child)) {
- list_del_init(&child->ptrace_list);
- remove_parent(child);
- child->parent = child->real_parent;
- add_parent(child);
- }
+ child->parent = child->real_parent;
+ list_del_init(&child->ptrace_entry);
+ arch_ptrace_untrace(child);
if (task_is_traced(child))
ptrace_untrace(child);
}
read_unlock(&tasklist_lock);
if (!ret && !kill)
- wait_task_inactive(child);
+ ret = wait_task_inactive(child, TASK_TRACED) ? 0 : -ESRCH;
/* All systems go.. */
return ret;
}
-int __ptrace_may_attach(struct task_struct *task)
+int __ptrace_may_access(struct task_struct *task, unsigned int mode)
{
+ const struct cred *cred = current_cred(), *tcred;
+
/* May we inspect the given task?
* This check is used both for attaching with ptrace
* and for allowing access to sensitive information in /proc.
/* 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->egid) ||
- (current->gid != task->sgid) ||
- (current->gid != task->gid)) && !capable(CAP_SYS_PTRACE))
+ rcu_read_lock();
+ tcred = __task_cred(task);
+ if ((cred->uid != tcred->euid ||
+ cred->uid != tcred->suid ||
+ cred->uid != tcred->uid ||
+ cred->gid != tcred->egid ||
+ cred->gid != tcred->sgid ||
+ cred->gid != tcred->gid) &&
+ !capable(CAP_SYS_PTRACE)) {
+ rcu_read_unlock();
return -EPERM;
+ }
+ rcu_read_unlock();
smp_rmb();
if (task->mm)
dumpable = get_dumpable(task->mm);
if (!dumpable && !capable(CAP_SYS_PTRACE))
return -EPERM;
- return security_ptrace(current, task);
+ return security_ptrace_may_access(task, mode);
}
-int ptrace_may_attach(struct task_struct *task)
+bool ptrace_may_access(struct task_struct *task, unsigned int mode)
{
int err;
task_lock(task);
- err = __ptrace_may_attach(task);
+ err = __ptrace_may_access(task, mode);
task_unlock(task);
- return !err;
+ return (!err ? true : false);
}
int ptrace_attach(struct task_struct *task)
if (same_thread_group(task, current))
goto out;
+ /* Protect exec's credential calculations against our interference;
+ * SUID, SGID and LSM creds get determined differently under ptrace.
+ */
+ retval = mutex_lock_interruptible(¤t->cred_exec_mutex);
+ if (retval < 0)
+ goto out;
+
+ retval = -EPERM;
repeat:
/*
* Nasty, nasty.
/* the same process cannot be attached many times */
if (task->ptrace & PT_PTRACED)
goto bad;
- retval = __ptrace_may_attach(task);
+ retval = __ptrace_may_access(task, PTRACE_MODE_ATTACH);
if (retval)
goto bad;
bad:
write_unlock_irqrestore(&tasklist_lock, flags);
task_unlock(task);
+ mutex_unlock(¤t->cred_exec_mutex);
out:
return retval;
}
/*
* Are we already being traced?
*/
+repeat:
task_lock(current);
if (!(current->ptrace & PT_PTRACED)) {
- ret = security_ptrace(current->parent, current);
+ /*
+ * See ptrace_attach() comments about the locking here.
+ */
+ unsigned long flags;
+ if (!write_trylock_irqsave(&tasklist_lock, flags)) {
+ task_unlock(current);
+ do {
+ cpu_relax();
+ } while (!write_can_lock(&tasklist_lock));
+ goto repeat;
+ }
+
+ ret = security_ptrace_traceme(current->parent);
+
/*
* Set the ptrace bit in the process ptrace flags.
+ * Then link us on our parent's ptraced list.
*/
- if (!ret)
+ if (!ret) {
current->ptrace |= PT_PTRACED;
+ __ptrace_link(current, current->real_parent);
+ }
+
+ write_unlock_irqrestore(&tasklist_lock, flags);
}
task_unlock(current);
return ret;
#define arch_ptrace_attach(child) do { } while (0)
#endif
-#ifndef __ARCH_SYS_PTRACE
-asmlinkage long sys_ptrace(long request, long pid, long addr, long data)
+SYSCALL_DEFINE4(ptrace, long, request, long, pid, long, addr, long, data)
{
struct task_struct *child;
long ret;
unlock_kernel();
return ret;
}
-#endif /* __ARCH_SYS_PTRACE */
int generic_ptrace_peekdata(struct task_struct *tsk, long addr, long data)
{
return (copied == sizeof(data)) ? 0 : -EIO;
}
-#if defined CONFIG_COMPAT && defined __ARCH_WANT_COMPAT_SYS_PTRACE
+#if defined CONFIG_COMPAT
#include <linux/compat.h>
int compat_ptrace_request(struct task_struct *child, compat_long_t request,
unlock_kernel();
return ret;
}
-#endif /* CONFIG_COMPAT && __ARCH_WANT_COMPAT_SYS_PTRACE */
+#endif /* CONFIG_COMPAT */
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff