[PATCH AUTOSEL 6.1 10/47] ksmbd: validate session id and tree id in compound request

From: Sasha Levin
Date: Sun Aug 13 2023 - 12:01:46 EST


From: Namjae Jeon <linkinjeon@xxxxxxxxxx>

[ Upstream commit 3df0411e132ee74a87aa13142dfd2b190275332e ]

`smb2_get_msg()` in smb2_get_ksmbd_tcon() and smb2_check_user_session()
will always return the first request smb2 header in a compound request.
if `SMB2_TREE_CONNECT_HE` is the first command in compound request, will
return 0, i.e. The tree id check is skipped.
This patch use ksmbd_req_buf_next() to get current command in compound.

Reported-by: zdi-disclosures@xxxxxxxxxxxxxx # ZDI-CAN-21506
Signed-off-by: Namjae Jeon <linkinjeon@xxxxxxxxxx>
Signed-off-by: Steve French <stfrench@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
fs/smb/server/smb2pdu.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/fs/smb/server/smb2pdu.c b/fs/smb/server/smb2pdu.c
index c33249393ef36..d2873dc4322d7 100644
--- a/fs/smb/server/smb2pdu.c
+++ b/fs/smb/server/smb2pdu.c
@@ -86,9 +86,9 @@ struct channel *lookup_chann_list(struct ksmbd_session *sess, struct ksmbd_conn
*/
int smb2_get_ksmbd_tcon(struct ksmbd_work *work)
{
- struct smb2_hdr *req_hdr = smb2_get_msg(work->request_buf);
+ struct smb2_hdr *req_hdr = ksmbd_req_buf_next(work);
unsigned int cmd = le16_to_cpu(req_hdr->Command);
- int tree_id;
+ unsigned int tree_id;

if (cmd == SMB2_TREE_CONNECT_HE ||
cmd == SMB2_CANCEL_HE ||
@@ -113,7 +113,7 @@ int smb2_get_ksmbd_tcon(struct ksmbd_work *work)
pr_err("The first operation in the compound does not have tcon\n");
return -EINVAL;
}
- if (work->tcon->id != tree_id) {
+ if (tree_id != UINT_MAX && work->tcon->id != tree_id) {
pr_err("tree id(%u) is different with id(%u) in first operation\n",
tree_id, work->tcon->id);
return -EINVAL;
@@ -565,9 +565,9 @@ int smb2_allocate_rsp_buf(struct ksmbd_work *work)
*/
int smb2_check_user_session(struct ksmbd_work *work)
{
- struct smb2_hdr *req_hdr = smb2_get_msg(work->request_buf);
+ struct smb2_hdr *req_hdr = ksmbd_req_buf_next(work);
struct ksmbd_conn *conn = work->conn;
- unsigned int cmd = conn->ops->get_cmd_val(work);
+ unsigned int cmd = le16_to_cpu(req_hdr->Command);
unsigned long long sess_id;

/*
@@ -593,7 +593,7 @@ int smb2_check_user_session(struct ksmbd_work *work)
pr_err("The first operation in the compound does not have sess\n");
return -EINVAL;
}
- if (work->sess->id != sess_id) {
+ if (sess_id != ULLONG_MAX && work->sess->id != sess_id) {
pr_err("session id(%llu) is different with the first operation(%lld)\n",
sess_id, work->sess->id);
return -EINVAL;
--
2.40.1