* to continually duplicate across every architecture.
*/
+#include <linux/capability.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/errno.h>
#include <linux/ptrace.h>
#include <linux/security.h>
#include <linux/signal.h>
+#include <linux/audit.h>
+#include <linux/pid_namespace.h>
#include <asm/pgtable.h>
#include <asm/uaccess.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) {
+ if (task_is_traced(child)) {
if (child->signal->flags & SIGNAL_STOP_STOPPED) {
- child->state = TASK_STOPPED;
+ __set_task_state(child, TASK_STOPPED);
} else {
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 (task_is_traced(child))
+ ptrace_untrace(child);
}
/*
&& child->signal != NULL) {
ret = 0;
spin_lock_irq(&child->sighand->siglock);
- if (child->state == TASK_STOPPED) {
+ if (task_is_stopped(child))
child->state = TASK_TRACED;
- } else if (child->state != TASK_TRACED && !kill) {
+ else if (!task_is_traced(child) && !kill)
ret = -ESRCH;
- }
spin_unlock_irq(&child->sighand->siglock);
}
read_unlock(&tasklist_lock);
- if (!ret && !kill) {
+ if (!ret && !kill)
wait_task_inactive(child);
- }
/* All systems go.. */
return ret;
}
-static int may_attach(struct task_struct *task)
+int __ptrace_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 = get_dumpable(task->mm);
+ if (!dumpable && !capable(CAP_SYS_PTRACE))
return -EPERM;
return security_ptrace(current, task);
{
int err;
task_lock(task);
- err = may_attach(task);
+ err = __ptrace_may_attach(task);
task_unlock(task);
return !err;
}
int ptrace_attach(struct task_struct *task)
{
int retval;
- task_lock(task);
+ unsigned long flags;
+
+ audit_ptrace(task);
+
retval = -EPERM;
if (task->pid <= 1)
- goto bad;
- if (task->tgid == current->tgid)
+ goto out;
+ if (same_thread_group(task, current))
+ 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);
+ if (!write_trylock_irqsave(&tasklist_lock, flags)) {
+ 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)
goto bad;
- retval = may_attach(task);
+ retval = __ptrace_may_attach(task);
if (retval)
goto bad;
? 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_irqrestore(&tasklist_lock, flags);
task_unlock(task);
+out:
return retval;
}
-int ptrace_detach(struct task_struct *child, unsigned int data)
+static inline void __ptrace_detach(struct task_struct *child, unsigned int data)
{
- if (!valid_signal(data))
- return -EIO;
-
- /* Architecture-specific hardware disable .. */
- ptrace_disable(child);
-
- /* .. re-parent .. */
child->exit_code = data;
-
- write_lock_irq(&tasklist_lock);
+ /* .. re-parent .. */
__ptrace_unlink(child);
/* .. and wake it up. */
if (child->exit_state != EXIT_ZOMBIE)
wake_up_process(child);
- write_unlock_irq(&tasklist_lock);
-
- return 0;
}
-/*
- * Access another process' address space.
- * Source/target buffer must be kernel space,
- * Do not walk the page table directly, use get_user_pages
- */
-
-int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write)
+int ptrace_detach(struct task_struct *child, unsigned int data)
{
- struct mm_struct *mm;
- struct vm_area_struct *vma;
- struct page *page;
- void *old_buf = buf;
+ if (!valid_signal(data))
+ return -EIO;
- mm = get_task_mm(tsk);
- if (!mm)
- return 0;
+ /* Architecture-specific hardware disable .. */
+ ptrace_disable(child);
+ clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
- down_read(&mm->mmap_sem);
- /* ignore errors, just check how much was sucessfully transfered */
- while (len) {
- int bytes, ret, offset;
- void *maddr;
-
- ret = get_user_pages(tsk, mm, addr, 1,
- write, 1, &page, &vma);
- if (ret <= 0)
- break;
-
- bytes = len;
- offset = addr & (PAGE_SIZE-1);
- if (bytes > PAGE_SIZE-offset)
- bytes = PAGE_SIZE-offset;
-
- maddr = kmap(page);
- if (write) {
- copy_to_user_page(vma, page, addr,
- maddr + offset, buf, bytes);
- if (!PageCompound(page))
- set_page_dirty_lock(page);
- } else {
- copy_from_user_page(vma, page, addr,
- buf, maddr + offset, bytes);
- }
- kunmap(page);
- page_cache_release(page);
- len -= bytes;
- buf += bytes;
- addr += bytes;
- }
- up_read(&mm->mmap_sem);
- mmput(mm);
-
- return buf - old_buf;
+ write_lock_irq(&tasklist_lock);
+ /* protect against de_thread()->release_task() */
+ if (child->ptrace)
+ __ptrace_detach(child, data);
+ write_unlock_irq(&tasklist_lock);
+
+ return 0;
}
int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len)
return error;
}
+
+#ifdef PTRACE_SINGLESTEP
+#define is_singlestep(request) ((request) == PTRACE_SINGLESTEP)
+#else
+#define is_singlestep(request) 0
+#endif
+
+#ifdef PTRACE_SINGLEBLOCK
+#define is_singleblock(request) ((request) == PTRACE_SINGLEBLOCK)
+#else
+#define is_singleblock(request) 0
+#endif
+
+#ifdef PTRACE_SYSEMU
+#define is_sysemu_singlestep(request) ((request) == PTRACE_SYSEMU_SINGLESTEP)
+#else
+#define is_sysemu_singlestep(request) 0
+#endif
+
+static int ptrace_resume(struct task_struct *child, long request, long data)
+{
+ if (!valid_signal(data))
+ return -EIO;
+
+ if (request == PTRACE_SYSCALL)
+ set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
+ else
+ clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
+
+#ifdef TIF_SYSCALL_EMU
+ if (request == PTRACE_SYSEMU || request == PTRACE_SYSEMU_SINGLESTEP)
+ set_tsk_thread_flag(child, TIF_SYSCALL_EMU);
+ else
+ clear_tsk_thread_flag(child, TIF_SYSCALL_EMU);
+#endif
+
+ if (is_singleblock(request)) {
+ if (unlikely(!arch_has_block_step()))
+ return -EIO;
+ user_enable_block_step(child);
+ } else if (is_singlestep(request) || is_sysemu_singlestep(request)) {
+ if (unlikely(!arch_has_single_step()))
+ return -EIO;
+ user_enable_single_step(child);
+ }
+ else
+ user_disable_single_step(child);
+
+ child->exit_code = data;
+ wake_up_process(child);
+
+ return 0;
+}
+
int ptrace_request(struct task_struct *child, long request,
long addr, long data)
{
int ret = -EIO;
switch (request) {
+ case PTRACE_PEEKTEXT:
+ case PTRACE_PEEKDATA:
+ return generic_ptrace_peekdata(child, addr, data);
+ case PTRACE_POKETEXT:
+ case PTRACE_POKEDATA:
+ return generic_ptrace_pokedata(child, addr, data);
+
#ifdef PTRACE_OLDSETOPTIONS
case PTRACE_OLDSETOPTIONS:
#endif
case PTRACE_SETSIGINFO:
ret = ptrace_setsiginfo(child, (siginfo_t __user *) data);
break;
+ case PTRACE_DETACH: /* detach a process that was attached. */
+ ret = ptrace_detach(child, data);
+ break;
+
+#ifdef PTRACE_SINGLESTEP
+ case PTRACE_SINGLESTEP:
+#endif
+#ifdef PTRACE_SINGLEBLOCK
+ case PTRACE_SINGLEBLOCK:
+#endif
+#ifdef PTRACE_SYSEMU
+ case PTRACE_SYSEMU:
+ case PTRACE_SYSEMU_SINGLESTEP:
+#endif
+ case PTRACE_SYSCALL:
+ case PTRACE_CONT:
+ return ptrace_resume(child, request, data);
+
+ case PTRACE_KILL:
+ if (child->exit_state) /* already dead */
+ return 0;
+ return ptrace_resume(child, request, SIGKILL);
+
default:
break;
}
return ret;
}
-#ifndef __ARCH_SYS_PTRACE
-static int ptrace_get_task_struct(long request, long pid,
- struct task_struct **childp)
+/**
+ * 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)
{
- struct task_struct *child;
- int ret;
+ int ret = -EPERM;
/*
- * Callers use child == NULL as an indication to exit early even
- * when the return value is 0, so make sure it is non-NULL here.
+ * Are we already being traced?
*/
- *childp = NULL;
-
- if (request == PTRACE_TRACEME) {
- /*
- * Are we already being traced?
- */
- if (current->ptrace & PT_PTRACED)
- return -EPERM;
+ task_lock(current);
+ if (!(current->ptrace & PT_PTRACED)) {
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;
+ if (!ret)
+ current->ptrace |= PT_PTRACED;
}
+ task_unlock(current);
+ return ret;
+}
+
+/**
+ * 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;
/*
- * You may not mess with init
+ * Tracing init is not allowed.
*/
if (pid == 1)
- return -EPERM;
+ return ERR_PTR(-EPERM);
- ret = -ESRCH;
read_lock(&tasklist_lock);
- child = find_task_by_pid(pid);
+ child = find_task_by_vpid(pid);
if (child)
get_task_struct(child);
+
read_unlock(&tasklist_lock);
if (!child)
- return -ESRCH;
-
- *childp = child;
- return 0;
+ return ERR_PTR(-ESRCH);
+ return child;
}
+#ifndef arch_ptrace_attach
+#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)
{
struct task_struct *child;
* This lock_kernel fixes a subtle race with suid exec
*/
lock_kernel();
- ret = ptrace_get_task_struct(request, pid, &child);
- if (!child)
+ if (request == PTRACE_TRACEME) {
+ ret = ptrace_traceme();
+ if (!ret)
+ arch_ptrace_attach(current);
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);
+ /*
+ * Some architectures need to do book-keeping after
+ * a ptrace attach.
+ */
+ if (!ret)
+ arch_ptrace_attach(child);
goto out_put_task_struct;
}
return ret;
}
#endif /* __ARCH_SYS_PTRACE */
+
+int generic_ptrace_peekdata(struct task_struct *tsk, long addr, long data)
+{
+ unsigned long tmp;
+ int copied;
+
+ copied = access_process_vm(tsk, addr, &tmp, sizeof(tmp), 0);
+ if (copied != sizeof(tmp))
+ return -EIO;
+ return put_user(tmp, (unsigned long __user *)data);
+}
+
+int generic_ptrace_pokedata(struct task_struct *tsk, long addr, long data)
+{
+ int copied;
+
+ copied = access_process_vm(tsk, addr, &data, sizeof(data), 1);
+ return (copied == sizeof(data)) ? 0 : -EIO;
+}
+
+#ifdef CONFIG_COMPAT
+#include <linux/compat.h>
+
+int compat_ptrace_request(struct task_struct *child, compat_long_t request,
+ compat_ulong_t addr, compat_ulong_t data)
+{
+ compat_ulong_t __user *datap = compat_ptr(data);
+ compat_ulong_t word;
+ int ret;
+
+ switch (request) {
+ case PTRACE_PEEKTEXT:
+ case PTRACE_PEEKDATA:
+ ret = access_process_vm(child, addr, &word, sizeof(word), 0);
+ if (ret != sizeof(word))
+ ret = -EIO;
+ else
+ ret = put_user(word, datap);
+ break;
+
+ case PTRACE_POKETEXT:
+ case PTRACE_POKEDATA:
+ ret = access_process_vm(child, addr, &data, sizeof(data), 1);
+ ret = (ret != sizeof(data) ? -EIO : 0);
+ break;
+
+ case PTRACE_GETEVENTMSG:
+ ret = put_user((compat_ulong_t) child->ptrace_message, datap);
+ break;
+
+ default:
+ ret = ptrace_request(child, request, addr, data);
+ }
+
+ return ret;
+}
+
+#ifdef __ARCH_WANT_COMPAT_SYS_PTRACE
+asmlinkage long compat_sys_ptrace(compat_long_t request, compat_long_t pid,
+ compat_long_t addr, compat_long_t 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);
+ /*
+ * Some architectures need to do book-keeping after
+ * a ptrace attach.
+ */
+ if (!ret)
+ arch_ptrace_attach(child);
+ goto out_put_task_struct;
+ }
+
+ ret = ptrace_check_attach(child, request == PTRACE_KILL);
+ if (!ret)
+ ret = compat_arch_ptrace(child, request, addr, data);
+
+ out_put_task_struct:
+ put_task_struct(child);
+ out:
+ unlock_kernel();
+ return ret;
+}
+#endif /* __ARCH_WANT_COMPAT_SYS_PTRACE */
+
+#endif /* CONFIG_COMPAT */