From 0ec76a110f432e98277e464b82ace8dd66571689 Mon Sep 17 00:00:00 2001 From: David Howells Date: Wed, 27 Sep 2006 01:50:15 -0700 Subject: [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//maps to only those regions actually mapped by a program. Signed-off-by: David Howells Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/ptrace.c | 54 ------------------------------------------------------ 1 file changed, 54 deletions(-) (limited to 'kernel/ptrace.c') 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; -- cgit v1.2.3