[PATCH] NOMMU: Check that access_process_vm() has a valid target

Check that access_process_vm() is accessing a valid mapping in the target
process.

This limits ptrace() accesses and accesses through /proc/<pid>/maps to only
those regions actually mapped by a program.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 0 insertions, 54 deletions

diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index 9a111f70145c..8aad0331d82e 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -241,60 +241,6 @@ int ptrace_detach(struct task_struct *child, unsigned int data)
         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)
-{
-        struct mm_struct *mm;
-        struct vm_area_struct *vma;
-        struct page *page;
-        void *old_buf = buf;
-
-        mm = get_task_mm(tsk);
-        if (!mm)
-                return 0;
-
-        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;
-}
-
 int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len)
 {
         int copied = 0;