* 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 <linux/syscalls.h>
#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.
*
* 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();
- if (child->parent == new_parent)
- return;
- list_add(&child->ptrace_list, &child->parent->ptrace_children);
- REMOVE_LINKS(child);
+ BUG_ON(!list_empty(&child->ptrace_entry));
+ list_add(&child->ptrace_entry, &new_parent->ptraced);
child->parent = new_parent;
- SET_LINKS(child);
}
/*
* TASK_TRACED, resume it now.
* Requires that irqs be disabled.
*/
-void ptrace_untrace(task_t *child)
+static 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);
- child->parent = child->real_parent;
- SET_LINKS(child);
- }
+ child->parent = child->real_parent;
+ list_del_init(&child->ptrace_entry);
- ptrace_untrace(child);
+ arch_ptrace_untrace(child);
+ if (task_is_traced(child))
+ ptrace_untrace(child);
}
/*
* be changed by us so it's not changing right after this.
*/
read_lock(&tasklist_lock);
- if ((child->ptrace & PT_PTRACED) && child->parent == current &&
- (!(child->ptrace & PT_ATTACHED) || child->real_parent != current)
- && child->signal != NULL) {
+ if ((child->ptrace & PT_PTRACED) && child->parent == current) {
ret = 0;
+ /*
+ * child->sighand can't be NULL, release_task()
+ * does ptrace_unlink() before __exit_signal().
+ */
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) {
- wait_task_inactive(child);
- }
+ if (!ret && !kill)
+ ret = wait_task_inactive(child, TASK_TRACED) ? 0 : -ESRCH;
/* All systems go.. */
return ret;
}
-static int may_attach(struct task_struct *task)
+int __ptrace_may_access(struct task_struct *task, unsigned int mode)
{
- 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))
+ 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.
+ *
+ * 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;
+ 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 && !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);
+ 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 = 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)
{
int retval;
- task_lock(task);
+ unsigned long flags;
+
+ audit_ptrace(task);
+
retval = -EPERM;
- if (task->pid <= 1)
- goto bad;
- if (task == current)
+ 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.
+ *
+ * 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_access(task, PTRACE_MODE_ATTACH);
if (retval)
goto bad;
/* Go */
- task->ptrace |= PT_PTRACED | ((task->real_parent != current)
- ? PT_ATTACHED : 0);
+ task->ptrace |= PT_PTRACED;
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;
+ send_sig_info(SIGSTOP, SEND_SIG_FORCED, task);
bad:
+ write_unlock_irqrestore(&tasklist_lock, flags);
task_unlock(task);
+ mutex_unlock(¤t->cred_exec_mutex);
+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);
- 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 (data & ~PTRACE_O_MASK) ? -EINVAL : 0;
}
-static int ptrace_getsiginfo(struct task_struct *child, siginfo_t __user * data)
+static int ptrace_getsiginfo(struct task_struct *child, siginfo_t *info)
{
- siginfo_t lastinfo;
int error = -ESRCH;
read_lock(&tasklist_lock);
error = -EINVAL;
spin_lock_irq(&child->sighand->siglock);
if (likely(child->last_siginfo != NULL)) {
- lastinfo = *child->last_siginfo;
+ *info = *child->last_siginfo;
error = 0;
}
spin_unlock_irq(&child->sighand->siglock);
}
read_unlock(&tasklist_lock);
- if (!error)
- return copy_siginfo_to_user(data, &lastinfo);
return error;
}
-static int ptrace_setsiginfo(struct task_struct *child, siginfo_t __user * data)
+static int ptrace_setsiginfo(struct task_struct *child, const siginfo_t *info)
{
- siginfo_t newinfo;
int error = -ESRCH;
- if (copy_from_user(&newinfo, data, sizeof (siginfo_t)))
- return -EFAULT;
-
read_lock(&tasklist_lock);
if (likely(child->sighand != NULL)) {
error = -EINVAL;
spin_lock_irq(&child->sighand->siglock);
if (likely(child->last_siginfo != NULL)) {
- *child->last_siginfo = newinfo;
+ *child->last_siginfo = *info;
error = 0;
}
spin_unlock_irq(&child->sighand->siglock);
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;
+ siginfo_t siginfo;
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_GETEVENTMSG:
ret = put_user(child->ptrace_message, (unsigned long __user *) data);
break;
+
case PTRACE_GETSIGINFO:
- ret = ptrace_getsiginfo(child, (siginfo_t __user *) data);
+ ret = ptrace_getsiginfo(child, &siginfo);
+ if (!ret)
+ ret = copy_siginfo_to_user((siginfo_t __user *) data,
+ &siginfo);
break;
+
case PTRACE_SETSIGINFO:
- ret = ptrace_setsiginfo(child, (siginfo_t __user *) data);
+ if (copy_from_user(&siginfo, (siginfo_t __user *) data,
+ sizeof siginfo))
+ ret = -EFAULT;
+ else
+ ret = ptrace_setsiginfo(child, &siginfo);
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;
}
+
+/**
+ * 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 = -EPERM;
+
+ /*
+ * Are we already being traced?
+ */
+repeat:
+ task_lock(current);
+ if (!(current->ptrace & PT_PTRACED)) {
+ /*
+ * 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) {
+ current->ptrace |= PT_PTRACED;
+ __ptrace_link(current, current->real_parent);
+ }
+
+ write_unlock_irqrestore(&tasklist_lock, flags);
+ }
+ 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;
+
+ read_lock(&tasklist_lock);
+ child = find_task_by_vpid(pid);
+ if (child)
+ get_task_struct(child);
+
+ read_unlock(&tasklist_lock);
+ if (!child)
+ return ERR_PTR(-ESRCH);
+ return child;
+}
+
+#ifndef arch_ptrace_attach
+#define arch_ptrace_attach(child) do { } while (0)
+#endif
+
+SYSCALL_DEFINE4(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();
+ 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;
+ }
+
+ 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;
+}
+
+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;
+}
+
+#if defined 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;
+ siginfo_t siginfo;
+ 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;
+
+ case PTRACE_GETSIGINFO:
+ ret = ptrace_getsiginfo(child, &siginfo);
+ if (!ret)
+ ret = copy_siginfo_to_user32(
+ (struct compat_siginfo __user *) datap,
+ &siginfo);
+ break;
+
+ case PTRACE_SETSIGINFO:
+ memset(&siginfo, 0, sizeof siginfo);
+ if (copy_siginfo_from_user32(
+ &siginfo, (struct compat_siginfo __user *) datap))
+ ret = -EFAULT;
+ else
+ ret = ptrace_setsiginfo(child, &siginfo);
+ break;
+
+ default:
+ ret = ptrace_request(child, request, addr, data);
+ }
+
+ return ret;
+}
+
+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 /* CONFIG_COMPAT */
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff