The local variable 'pos' comes from userspace. If a large number was
passed, there would be an integer overflow in the following line:
        pos += n;

Signed-off-by: Wenliang Fan <fanwle...@gmail.com>
---
 fs/nilfs2/ioctl.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/fs/nilfs2/ioctl.c b/fs/nilfs2/ioctl.c
index b44bdb2..b2bac9a 100644
--- a/fs/nilfs2/ioctl.c
+++ b/fs/nilfs2/ioctl.c
@@ -90,8 +90,13 @@ static int nilfs_ioctl_wrap_copy(struct the_nilfs *nilfs,
                total += nr;
                if ((size_t)nr < n)
                        break;
-               if (pos == ppos)
+               if (pos == ppos) {
+                       if (pos > ULONG_MAX - n) {
+                               ret = -EINVAL;
+                               break;
+                       }
                        pos += n;
+               }
        }
        argv->v_nmembs = total;
 
-- 
1.8.5.rc1.28.g7061504

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