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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        syzbot+f3ce716af730c8f96637@syzkaller.appspotmail.com,
        Myungho Jung <mhjungk@gmail.com>,
        Parav Pandit <parav@mellanox.com>,
        Jason Gunthorpe <jgg@mellanox.com>
Subject: [PATCH 5.0 42/52] RDMA/cma: Rollback source IP address if failing to acquire device
Date:   Tue, 26 Mar 2019 15:30:29 +0900
Message-Id: <20190326042703.214495584@linuxfoundation.org>
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5.0-stable review patch.  If anyone has any objections, please let me know.

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

From: Myungho Jung <mhjungk@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+f3ce716af730c8f96637@syzkaller.appspotmail.com
Signed-off-by: Myungho Jung <mhjungk@gmail.com>
Reviewed-by: Parav Pandit <parav@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@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
@@ -2966,13 +2966,22 @@ 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_by_src_ip(id_priv);
 		if (status)
@@ -2983,6 +2992,8 @@ 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;