Merge to Fedora kernel-2.6.18-1.2255_FC5-vs2.0.2.2-rc9 patched with stable patch...

[linux-2.6.git] / kernel / ptrace.c

diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index ad5df5a..80e780e 100644 (file)
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -18,7 +18,7 @@
 #include <linux/ptrace.h>
 #include <linux/security.h>
 #include <linux/signal.h>
-#include <linux/vs_cvirt.h>
+#include <linux/vs_base.h>
 
 #include <asm/pgtable.h>
 #include <asm/uaccess.h>
@@ -29,7 +29,7 @@
  *
  * 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)
 {
        BUG_ON(!list_empty(&child->ptrace_list));
        if (child->parent == new_parent)
@@ -47,7 +47,7 @@ void __ptrace_link(task_t *child, task_t *new_parent)
  * 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) {
@@ -66,7 +66,7 @@ void ptrace_untrace(task_t *child)
  *
  * Must be called with the tasklist lock write-held.
  */
-void __ptrace_unlink(task_t *child)
+void __ptrace_unlink(struct task_struct *child)
 {
        BUG_ON(!child->ptrace);
 
@@ -111,18 +111,24 @@ int ptrace_check_attach(struct task_struct *child, int kill)
        }
        read_unlock(&tasklist_lock);
 
-       if (!ret && !kill) {
-               wait_task_inactive(child);
-       }
-
        /* All systems go.. */
        return ret;
 }
 
 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) ||
@@ -131,7 +137,9 @@ int __ptrace_may_attach(struct task_struct *task)
             (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);
@@ -177,6 +185,8 @@ repeat:
                goto repeat;
        }
 
+       if (!task->mm)
+               goto bad;
        /* the same process cannot be attached many times */
        if (task->ptrace & PT_PTRACED)
                goto bad;
@@ -201,7 +211,7 @@ out:
        return retval;
 }
 
-void __ptrace_detach(struct task_struct *child, unsigned int data)
+static inline void __ptrace_detach(struct task_struct *child, unsigned int data)
 {
        child->exit_code = data;
        /* .. re-parent .. */
@@ -220,6 +230,7 @@ int ptrace_detach(struct task_struct *child, unsigned int data)
        ptrace_disable(child);
 
        write_lock_irq(&tasklist_lock);
+       /* protect against de_thread()->release_task() */
        if (child->ptrace)
                __ptrace_detach(child, data);
        write_unlock_irq(&tasklist_lock);