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From:   Jeff Layton <jlayton@kernel.org>
To:     idryomov@gmail.com, xiubli@redhat.com
Cc:     ceph-devel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
        linux-fscrypt@vger.kernel.org, linux-kernel@vger.kernel.org,
        lhenriques@suse.de
Subject: [RFC PATCH v11 21/51] ceph: fix base64 encoded name's length check in ceph_fname_to_usr()
Date:   Tue, 22 Mar 2022 10:12:46 -0400
Message-Id: <20220322141316.41325-22-jlayton@kernel.org>
In-Reply-To: <20220322141316.41325-1-jlayton@kernel.org>
References: <20220322141316.41325-1-jlayton@kernel.org>
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From: Xiubo Li <xiubli@redhat.com>

The fname->name is based64_encoded names and the max long shouldn't
exceed the NAME_MAX.

The FSCRYPT_BASE64URL_CHARS(NAME_MAX) will be 255 * 4 / 3.

Signed-off-by: Xiubo Li <xiubli@redhat.com>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
---
 fs/ceph/crypto.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/ceph/crypto.c b/fs/ceph/crypto.c
index 86de8483032f..e56017d66354 100644
--- a/fs/ceph/crypto.c
+++ b/fs/ceph/crypto.c
@@ -204,7 +204,7 @@ int ceph_fname_to_usr(const struct ceph_fname *fname, struct fscrypt_str *tname,
 	}
 
 	/* Sanity check that the resulting name will fit in the buffer */
-	if (fname->name_len > FSCRYPT_BASE64URL_CHARS(NAME_MAX))
+	if (fname->name_len > NAME_MAX || fname->ctext_len > NAME_MAX)
 		return -EIO;
 
 	ret = __fscrypt_prepare_readdir(fname->dir);
-- 
2.35.1