[SCSI] libiscsi_tcp: fix max_r2t manipulation
Problem description from Xi Wang:
A large max_r2t could lead to integer overflow in subsequent call to
iscsi_tcp_r2tpool_alloc(), allocating a smaller buffer than expected
and leading to out-of-bounds write.
Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
diff --git a/drivers/scsi/iscsi_tcp.c b/drivers/scsi/iscsi_tcp.c
index db47158..453a740 100644
--- a/drivers/scsi/iscsi_tcp.c
+++ b/drivers/scsi/iscsi_tcp.c
@@ -684,10 +684,8 @@
int buflen)
{
struct iscsi_conn *conn = cls_conn->dd_data;
- struct iscsi_session *session = conn->session;
struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
struct iscsi_sw_tcp_conn *tcp_sw_conn = tcp_conn->dd_data;
- int value;
switch(param) {
case ISCSI_PARAM_HDRDGST_EN:
@@ -699,16 +697,7 @@
sock_no_sendpage : tcp_sw_conn->sock->ops->sendpage;
break;
case ISCSI_PARAM_MAX_R2T:
- sscanf(buf, "%d", &value);
- if (value <= 0 || !is_power_of_2(value))
- return -EINVAL;
- if (session->max_r2t == value)
- break;
- iscsi_tcp_r2tpool_free(session);
- iscsi_set_param(cls_conn, param, buf, buflen);
- if (iscsi_tcp_r2tpool_alloc(session))
- return -ENOMEM;
- break;
+ return iscsi_tcp_set_max_r2t(conn, buf);
default:
return iscsi_set_param(cls_conn, param, buf, buflen);
}
