From: Namjae Jeon linkinjeon@kernel.org
commit 30210947a343b6b3ca13adc9bfc88e1543e16dd5 upstream.
There is UAF issue under cocurrent smb2 tree disconnect. This patch introduce TREE_CONN_EXPIRE flags for tcon to avoid cocurrent access.
Cc: stable@vger.kernel.org Reported-by: zdi-disclosures@trendmicro.com # ZDI-CAN-20592 Signed-off-by: Namjae Jeon linkinjeon@kernel.org Signed-off-by: Steve French stfrench@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/ksmbd/mgmt/tree_connect.c | 10 +++++++++- fs/ksmbd/mgmt/tree_connect.h | 3 +++ fs/ksmbd/smb2pdu.c | 3 ++- 3 files changed, 14 insertions(+), 2 deletions(-)
--- a/fs/ksmbd/mgmt/tree_connect.c +++ b/fs/ksmbd/mgmt/tree_connect.c @@ -109,7 +109,15 @@ int ksmbd_tree_conn_disconnect(struct ks struct ksmbd_tree_connect *ksmbd_tree_conn_lookup(struct ksmbd_session *sess, unsigned int id) { - return xa_load(&sess->tree_conns, id); + struct ksmbd_tree_connect *tcon; + + tcon = xa_load(&sess->tree_conns, id); + if (tcon) { + if (test_bit(TREE_CONN_EXPIRE, &tcon->status)) + tcon = NULL; + } + + return tcon; }
struct ksmbd_share_config *ksmbd_tree_conn_share(struct ksmbd_session *sess, --- a/fs/ksmbd/mgmt/tree_connect.h +++ b/fs/ksmbd/mgmt/tree_connect.h @@ -14,6 +14,8 @@ struct ksmbd_share_config; struct ksmbd_user; struct ksmbd_conn;
+#define TREE_CONN_EXPIRE 1 + struct ksmbd_tree_connect { int id;
@@ -25,6 +27,7 @@ struct ksmbd_tree_connect {
int maximal_access; bool posix_extensions; + unsigned long status; };
struct ksmbd_tree_conn_status { --- a/fs/ksmbd/smb2pdu.c +++ b/fs/ksmbd/smb2pdu.c @@ -2053,11 +2053,12 @@ int smb2_tree_disconnect(struct ksmbd_wo
ksmbd_debug(SMB, "request\n");
- if (!tcon) { + if (!tcon || test_and_set_bit(TREE_CONN_EXPIRE, &tcon->status)) { struct smb2_tree_disconnect_req *req = smb2_get_msg(work->request_buf);
ksmbd_debug(SMB, "Invalid tid %d\n", req->hdr.Id.SyncId.TreeId); + rsp->hdr.Status = STATUS_NETWORK_NAME_DELETED; smb2_set_err_rsp(work); return 0;