Commit 910e46da authored Sep 27, 2006 by Sonic Zhang Committed by Linus Torvalds Sep 27, 2006

[PATCH] Check if start address is in vma region in NOMMU function get_user_pages()



In NOMMU arch, if run "cat /proc/self/mem", data from physical address 0
are read.  This behavior is different from MMU arch.  In IA32, message
"cat: /proc/self/mem: Input/output error" is reported.

This issue is rootcaused by not validate the start address in NOMMU
function get_user_pages().  Following patch solves this issue.

Signed-off-by: Sonic Zhang <sonic.adi@gmail.com>
Cc: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

parent 0159b141

mm/nommu.c

+6 −2

Original line number	Diff line number	Diff line
		@@ -129,16 +129,20 @@ int get_user_pages(struct task_struct tsk, struct mm_struct mm,
		struct page pages, struct vm_area_struct vmas)
		{
		int i;
		static struct vm_area_struct dummy_vma;
		struct vm_area_struct *vma;

		for (i = 0; i < len; i++) {
		vma = find_vma(mm, start);
		if(!vma)
		return i ? : -EFAULT;

		if (pages) {
		pages[i] = virt_to_page(start);
		if (pages[i])
		page_cache_get(pages[i]);
		}
		if (vmas)
		vmas[i] = &dummy_vma;
		vmas[i] = vma;
		start += PAGE_SIZE;
		}
		return(i);

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