uprobes: Fix overflow in vma_address()/find_active_uprobe()

vma->vm_pgoff is "unsigned long", it should be promoted to
loff_t before the multiplication to avoid the overflow.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar.vnet.ibm.com>
Cc: Anton Arapov <anton@redhat.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/20120729182233.GA20339@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index 9db9cdf8ff346d00cb682068544ae3307d3b5116..fb961d5e205cfa038cf0417d6c93662efc100134 100644 (file)
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -117,7 +117,7 @@ static loff_t vma_address(struct vm_area_struct *vma, loff_t offset)
        loff_t vaddr;
 
        vaddr = vma->vm_start + offset;
-       vaddr -= vma->vm_pgoff << PAGE_SHIFT;
+       vaddr -= (loff_t)vma->vm_pgoff << PAGE_SHIFT;
 
        return vaddr;
 }
@@ -1450,7 +1450,7 @@ static struct uprobe *find_active_uprobe(unsigned long bp_vaddr, int *is_swbp)
 
                        inode = vma->vm_file->f_mapping->host;
                        offset = bp_vaddr - vma->vm_start;
-                       offset += (vma->vm_pgoff << PAGE_SHIFT);
+                       offset += (loff_t)vma->vm_pgoff << PAGE_SHIFT;
                        uprobe = find_uprobe(inode, offset);
                }