linux-kernel - [PATCH 6.1.y] smb/server: fix potential null-ptr-deref of lease_ctx_info in smb2

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Message-ID: <20250416010252.388173-1-jianqi.ren.cn@windriver.com>
Date: Wed, 16 Apr 2025 09:02:52 +0800
From: <jianqi.ren.cn@...driver.com>
To: <stable@...r.kernel.org>
CC: <patches@...ts.linux.dev>, <gregkh@...uxfoundation.org>,
        <linux-kernel@...r.kernel.org>, <jianqi.ren.cn@...driver.com>,
        <chenxiaosong@...inos.cn>, <stfrench@...rosoft.com>,
        <linkinjeon@...nel.org>, <sfrench@...ba.org>,
        <senozhatsky@...omium.org>, <tom@...pey.com>,
        <linux-cifs@...r.kernel.org>
Subject: [PATCH 6.1.y] smb/server: fix potential null-ptr-deref of lease_ctx_info in smb2_open()

From: ChenXiaoSong <chenxiaosong@...inos.cn>

[ Upstream commit 4e8771a3666c8f216eefd6bd2fd50121c6c437db ]

null-ptr-deref will occur when (req_op_level == SMB2_OPLOCK_LEVEL_LEASE)
and parse_lease_state() return NULL.

Fix this by check if 'lease_ctx_info' is NULL.

Additionally, remove the redundant parentheses in
parse_durable_handle_context().

Signed-off-by: ChenXiaoSong <chenxiaosong@...inos.cn>
Signed-off-by: Steve French <stfrench@...rosoft.com>
[Drop the parentheses clean-up since the parentheses was introduced by
c8efcc786146 ("ksmbd: add support for durable handles v1/v2") in v6.9
 Minor context change fixed]
Signed-off-by: Jianqi Ren <jianqi.ren.cn@...driver.com>
Signed-off-by: He Zhe <zhe.he@...driver.com>
---
Verified the build test
---
 fs/smb/server/oplock.c  | 2 +-
 fs/smb/server/smb2pdu.c | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/smb/server/oplock.c b/fs/smb/server/oplock.c
index a3c016a11e27..2fcfabc35b06 100644
--- a/fs/smb/server/oplock.c
+++ b/fs/smb/server/oplock.c
@@ -1515,7 +1515,7 @@ void create_lease_buf(u8 *rbuf, struct lease *lease)
  * @open_req:	buffer containing smb2 file open(create) request
  * @is_dir:	whether leasing file is directory
  *
- * Return:  oplock state, -ENOENT if create lease context not found
+ * Return: allocated lease context object on success, otherwise NULL
  */
 struct lease_ctx_info *parse_lease_state(void *open_req, bool is_dir)
 {
diff --git a/fs/smb/server/smb2pdu.c b/fs/smb/server/smb2pdu.c
index dbe272970c25..937c1cd2284e 100644
--- a/fs/smb/server/smb2pdu.c
+++ b/fs/smb/server/smb2pdu.c
@@ -3241,7 +3241,7 @@ int smb2_open(struct ksmbd_work *work)
 			goto err_out1;
 		}
 	} else {
-		if (req_op_level == SMB2_OPLOCK_LEVEL_LEASE) {
+		if (req_op_level == SMB2_OPLOCK_LEVEL_LEASE && lc) {
 			/*
 			 * Compare parent lease using parent key. If there is no
 			 * a lease that has same parent key, Send lease break
-- 
2.34.1