bail out with ELOOP earlier in do_link loop

If we'd passed through 32 trailing symlinks already, there's
no sense following the 33rd - we'll bail out anyway.  Better
bugger off earlier.

It *does* change behaviour, after a fashion - if the 33rd happens
to be a procfs-style symlink, original code *would* allow it.
This one will not.  Cry me a river if that hurts you.  Please, do.
And post a video of that, while you are at it.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 1 insertions, 6 deletions

diff --git a/fs/namei.c b/fs/namei.c
index 976fc323272e..84f1ec3b4a5d 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1873,7 +1873,7 @@ exit_parent:
 
 do_link:
         error = -ELOOP;
-        if (flag & O_NOFOLLOW)
+        if ((flag & O_NOFOLLOW) || count++ == 32)
                 goto exit_dput;
         /*
          * This is subtle. Instead of calling do_follow_link() we do the
@@ -1915,11 +1915,6 @@ do_link:
                 __putname(nd.last.name);
                 goto exit;
         }
-        error = -ELOOP;
-        if (count++==32) {
-                __putname(nd.last.name);
-                goto exit;
-        }
         filp = do_last(&nd, &path, open_flag, flag, acc_mode, mode,
                        pathname, &is_link);
         __putname(nd.last.name);