From: Miklos Szeredi <mszeredi@redhat.com>
Date: Tue, 12 Nov 2019 10:49:04 +0000 (+0100)
Subject: fuse: verify nlink
X-Git-Tag: v5.5-rc1~35^2~6
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=c634da718db9b2fac201df2ae1b1b095344ce5eb;p=thirdparty%2Flinux.git

fuse: verify nlink

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>
---

diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index ca4ddbe21ec02..ee190119f45cc 100644
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -870,7 +870,8 @@ static int fuse_link(struct dentry *entry, struct inode *newdir,
 
 		spin_lock(&fi->lock);
 		fi->attr_version = atomic64_inc_return(&fc->attr_version);
-		inc_nlink(inode);
+		if (likely(inode->i_nlink < UINT_MAX))
+			inc_nlink(inode);
 		spin_unlock(&fi->lock);
 		fuse_invalidate_attr(inode);
 		fuse_update_ctime(inode);