From: Miklos Szeredi <mszeredi@redhat.com>
Date: Tue, 12 Nov 2019 10:49:04 +0000 (+0100)
Subject: fuse: verify nlink
X-Git-Tag: android-x86-9.0-r1~4^2~24^2~59
X-Git-Url: http://git.osdn.net/view?a=commitdiff_plain;h=9f435a5e3f5f28e20a6b6cfc2301cf5310f6238a;p=android-x86%2Fkernel.git

fuse: verify nlink

commit c634da718db9b2fac201df2ae1b1b095344ce5eb upstream.

When adding a new hard link, make sure that i_nlink doesn't overflow.

Fixes: ac45d61357e8 ("fuse: fix nlink after unlink")
Cc: <stable@vger.kernel.org> # v3.4
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index e7a2a988533d..1df6a6f3d8fd 100644
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -837,7 +837,8 @@ static int fuse_link(struct dentry *entry, struct inode *newdir,
 
 		spin_lock(&fc->lock);
 		fi->attr_version = ++fc->attr_version;
-		inc_nlink(inode);
+		if (likely(inode->i_nlink < UINT_MAX))
+			inc_nlink(inode);
 		spin_unlock(&fc->lock);
 		fuse_invalidate_attr(inode);
 		fuse_update_ctime(inode);