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From:   Ben Hutchings <ben@decadent.org.uk>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
CC:     akpm@linux-foundation.org, "Leon Romanovsky" <leonro@mellanox.com>,
        "" <syzbot+71655d44855ac3e76366@syzkaller.appspotmail.com>,
        "Jason Gunthorpe" <jgg@mellanox.com>
Date:   Thu, 07 Jun 2018 15:05:21 +0100
Message-ID: <lsq.1528380321.204512934@decadent.org.uk>
Subject: [PATCH 3.16 408/410] RDMA/ucma: Check that device exists prior to
 accessing it
In-Reply-To: <lsq.1528380320.647747352@decadent.org.uk>
Sender: linux-kernel-owner@vger.kernel.org
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3.16.57-rc1 review patch.  If anyone has any objections, please let me know.

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

From: Leon Romanovsky <leonro@mellanox.com>

commit c8d3bcbfc5eab3f01cf373d039af725f3b488813 upstream.

Ensure that device exists prior to accessing its properties.

Reported-by: <syzbot+71655d44855ac3e76366@syzkaller.appspotmail.com>
Fixes: 75216638572f ("RDMA/cma: Export rdma cm interface to userspace")
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
 drivers/infiniband/core/ucma.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

--- a/drivers/infiniband/core/ucma.c
+++ b/drivers/infiniband/core/ucma.c
@@ -1229,7 +1229,7 @@ static ssize_t ucma_notify(struct ucma_f
 {
 	struct rdma_ucm_notify cmd;
 	struct ucma_context *ctx;
-	int ret;
+	int ret = -EINVAL;
 
 	if (copy_from_user(&cmd, inbuf, sizeof(cmd)))
 		return -EFAULT;
@@ -1238,7 +1238,9 @@ static ssize_t ucma_notify(struct ucma_f
 	if (IS_ERR(ctx))
 		return PTR_ERR(ctx);
 
-	ret = rdma_notify(ctx->cm_id, (enum ib_event_type) cmd.event);
+	if (ctx->cm_id->device)
+		ret = rdma_notify(ctx->cm_id, (enum ib_event_type)cmd.event);
+
 	ucma_put_ctx(ctx);
 	return ret;
 }