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From:   Chengguang Xu <cgxu519@mykernel.net>
To:     trond.myklebust@hammerspace.com, anna.schumaker@netapp.com
Cc:     linux-nfs@vger.kernel.org, Chengguang Xu <cgxu519@mykernel.net>
Message-ID: <20200617010939.19087-1-cgxu519@mykernel.net>
Subject: [PATCH] nfs4: strengthen error check to avoid unexpected result
Date:   Wed, 17 Jun 2020 09:09:39 +0800
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Sender: linux-nfs-owner@vger.kernel.org
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The variable error is ssize_t, which is signed and will
cast to unsigned when comapre with variable size, so add
a check to avoid unexpected result in case of negative
value of error.

Signed-off-by: Chengguang Xu <cgxu519@mykernel.net>
---
 fs/nfs/nfs4proc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 9056f3dd380e..5f04c6f818b8 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -7392,7 +7392,7 @@ nfs4_listxattr_nfs4_label(struct inode *inode, char *=
list, size_t list_len)
=20
 =09if (nfs_server_capable(inode, NFS_CAP_SECURITY_LABEL)) {
 =09=09len =3D security_inode_listsecurity(inode, list, list_len);
-=09=09if (list_len && len > list_len)
+=09=09if (len >=3D 0 && list_len && len > list_len)
 =09=09=09return -ERANGE;
 =09}
 =09return len;
--=20
2.20.1