Merge tag 'media/v4.16-4' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab...

[sfrench/cifs-2.6.git] / fs / hugetlbfs / inode.c

diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
index 8fe1b0aa2896bc547955b8760bffea0ec326d7e8..b9a254dcc0e77e72873b9b49cf49787bd2154678 100644 (file)
--- a/fs/hugetlbfs/inode.c
+++ b/fs/hugetlbfs/inode.c
@@ -108,6 +108,16 @@ static void huge_pagevec_release(struct pagevec *pvec)
        pagevec_reinit(pvec);
 }
 
+/*
+ * Mask used when checking the page offset value passed in via system
+ * calls.  This value will be converted to a loff_t which is signed.
+ * Therefore, we want to check the upper PAGE_SHIFT + 1 bits of the
+ * value.  The extra bit (- 1 in the shift value) is to take the sign
+ * bit into account.
+ */
+#define PGOFF_LOFFT_MAX \
+       (((1UL << (PAGE_SHIFT + 1)) - 1) <<  (BITS_PER_LONG - (PAGE_SHIFT + 1)))
+
 static int hugetlbfs_file_mmap(struct file *file, struct vm_area_struct *vma)
 {
        struct inode *inode = file_inode(file);
@@ -127,12 +137,13 @@ static int hugetlbfs_file_mmap(struct file *file, struct vm_area_struct *vma)
        vma->vm_ops = &hugetlb_vm_ops;
 
        /*
-        * Offset passed to mmap (before page shift) could have been
-        * negative when represented as a (l)off_t.
+        * page based offset in vm_pgoff could be sufficiently large to
+        * overflow a (l)off_t when converted to byte offset.
         */
-       if (((loff_t)vma->vm_pgoff << PAGE_SHIFT) < 0)
+       if (vma->vm_pgoff & PGOFF_LOFFT_MAX)
                return -EINVAL;
 
+       /* must be huge page aligned */
        if (vma->vm_pgoff & (~huge_page_mask(h) >> PAGE_SHIFT))
                return -EINVAL;