[PATCH 4.19 35/45] RDMA/cma: Rollback source IP address if failing to acquire device

[Greg Kroah-Hartman]

4.19-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Myungho Jung <mhju...@gmail.com>

commit 5fc01fb846bce8fa6d5f95e2625b8ce0f8e86810 upstream.

If cma_acquire_dev_by_src_ip() returns error in addr_handler(), the
device state changes back to RDMA_CM_ADDR_BOUND but the resolved source
IP address is still left. After that, if rdma_destroy_id() is called
after rdma_listen(), the device is freed without removed from
listen_any_list in cma_cancel_operation(). Revert to the previous IP
address if acquiring device fails.

Reported-by: syzbot+f3ce716af730c8f96...@syzkaller.appspotmail.com
Signed-off-by: Myungho Jung <mhju...@gmail.com>
Reviewed-by: Parav Pandit <pa...@mellanox.com>
Signed-off-by: Jason Gunthorpe <j...@mellanox.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>

---
 drivers/infiniband/core/cma.c |   13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

--- a/drivers/infiniband/core/cma.c
+++ b/drivers/infiniband/core/cma.c
@@ -2854,13 +2854,22 @@ static void addr_handler(int status, str
 {
        struct rdma_id_private *id_priv = context;
        struct rdma_cm_event event = {};
+       struct sockaddr *addr;
+       struct sockaddr_storage old_addr;
 
        mutex_lock(&id_priv->handler_mutex);
        if (!cma_comp_exch(id_priv, RDMA_CM_ADDR_QUERY,
                           RDMA_CM_ADDR_RESOLVED))
                goto out;
 
-       memcpy(cma_src_addr(id_priv), src_addr, rdma_addr_size(src_addr));
+       /*
+        * Store the previous src address, so that if we fail to acquire
+        * matching rdma device, old address can be restored back, which helps
+        * to cancel the cma listen operation correctly.
+        */
+       addr = cma_src_addr(id_priv);
+       memcpy(&old_addr, addr, rdma_addr_size(addr));
+       memcpy(addr, src_addr, rdma_addr_size(src_addr));
        if (!status && !id_priv->cma_dev) {
                status = cma_acquire_dev(id_priv, NULL);
                if (status)
@@ -2871,6 +2880,8 @@ static void addr_handler(int status, str
        }
 
        if (status) {
+               memcpy(addr, &old_addr,
+                      rdma_addr_size((struct sockaddr *)&old_addr));
                if (!cma_comp_exch(id_priv, RDMA_CM_ADDR_RESOLVED,
                                   RDMA_CM_ADDR_BOUND))
                        goto out;