From: Sonic Zhang <[email protected]>
Hi,
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.
Thanks
Sonic Zhang
Signed-off-by: Sonic Zhang <[email protected]>
Signed-Off-By: David Howells <[email protected]>
---
mm/nommu.c | 8 ++++++--
1 files changed, 6 insertions(+), 2 deletions(-)
diff --git a/mm/nommu.c b/mm/nommu.c
index 3215f46..2fe3fe4 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -129,16 +129,20 @@ int get_user_pages(struct task_struct *t
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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