diff options
| -rw-r--r-- | mm/mremap.c | 15 |
1 files changed, 13 insertions, 2 deletions
diff --git a/mm/mremap.c b/mm/mremap.c index 63782eb8e5a..a27c00798c2 100644 --- a/mm/mremap.c +++ b/mm/mremap.c @@ -333,10 +333,21 @@ unsigned long do_mremap(unsigned long addr, /* We can't remap across vm area boundaries */ if (old_len > vma->vm_end - addr) goto out; - if (vma->vm_flags & (VM_DONTEXPAND | VM_PFNMAP)) { - if (new_len > old_len) + + /* Need to be careful about a growing mapping */ + if (new_len > old_len) { + unsigned long pgoff; + + if (vma->vm_flags & (VM_DONTEXPAND | VM_PFNMAP)) goto out; + pgoff = (addr - vma->vm_start) >> PAGE_SHIFT; + pgoff += vma->vm_pgoff; + if (pgoff + (new_len >> PAGE_SHIFT) < pgoff) { + ret = -EINVAL; + goto out; + } } + if (vma->vm_flags & VM_LOCKED) { unsigned long locked, lock_limit; locked = mm->locked_vm << PAGE_SHIFT; |