linux-kernel - [PATCH v2 02/12] smb/server: fix potential null-ptr-deref of lease_ctx_info in smb2

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Message-Id: <20240822082101.391272-3-chenxiaosong@chenxiaosong.com>
Date: Thu, 22 Aug 2024 08:20:51 +0000
From: chenxiaosong@...nxiaosong.com
To: linkinjeon@...nel.org,
	sfrench@...ba.org,
	senozhatsky@...omium.org,
	tom@...pey.com,
	linux-cifs@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	pc@...guebit.com,
	ronniesahlberg@...il.com,
	sprasad@...rosoft.com,
	bharathsm@...rosoft.com
Cc: chenxiaosong@...inos.cn,
	liuzhengyuan@...inos.cn,
	huhai@...inos.cn,
	liuyun01@...inos.cn,
	chenxiaosong@...nxiaosong.com
Subject: [PATCH v2 02/12] smb/server: fix potential null-ptr-deref of lease_ctx_info in smb2_open()

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

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>
---
 fs/smb/server/oplock.c  |  2 +-
 fs/smb/server/smb2pdu.c | 10 +++++-----
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/fs/smb/server/oplock.c b/fs/smb/server/oplock.c
index a8f52c4ebbda..e546ffa57b55 100644
--- a/fs/smb/server/oplock.c
+++ b/fs/smb/server/oplock.c
@@ -1510,7 +1510,7 @@ void create_lease_buf(u8 *rbuf, struct lease *lease)
  * parse_lease_state() - parse lease context containted in file open request
  * @open_req:	buffer containing smb2 file open(create) request
  *
- * 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)
 {
diff --git a/fs/smb/server/smb2pdu.c b/fs/smb/server/smb2pdu.c
index d8a827e0dced..154bc27d1db8 100644
--- a/fs/smb/server/smb2pdu.c
+++ b/fs/smb/server/smb2pdu.c
@@ -2767,8 +2767,8 @@ static int parse_durable_handle_context(struct ksmbd_work *work,
 				}
 			}
 
-			if (((lc && (lc->req_state & SMB2_LEASE_HANDLE_CACHING_LE)) ||
-			     req_op_level == SMB2_OPLOCK_LEVEL_BATCH)) {
+			if ((lc && (lc->req_state & SMB2_LEASE_HANDLE_CACHING_LE)) ||
+			    req_op_level == SMB2_OPLOCK_LEVEL_BATCH) {
 				dh_info->CreateGuid =
 					durable_v2_blob->CreateGuid;
 				dh_info->persistent =
@@ -2788,8 +2788,8 @@ static int parse_durable_handle_context(struct ksmbd_work *work,
 				goto out;
 			}
 
-			if (((lc && (lc->req_state & SMB2_LEASE_HANDLE_CACHING_LE)) ||
-			     req_op_level == SMB2_OPLOCK_LEVEL_BATCH)) {
+			if ((lc && (lc->req_state & SMB2_LEASE_HANDLE_CACHING_LE)) ||
+			    req_op_level == SMB2_OPLOCK_LEVEL_BATCH) {
 				ksmbd_debug(SMB, "Request for durable open\n");
 				dh_info->type = dh_idx;
 			}
@@ -3411,7 +3411,7 @@ 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) {
 			if (S_ISDIR(file_inode(filp)->i_mode)) {
 				lc->req_state &= ~SMB2_LEASE_WRITE_CACHING_LE;
 				lc->is_dir = true;
-- 
2.34.1