RDMA/ucma: Check that device exists prior to accessing it

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>

diff --git a/drivers/infiniband/core/ucma.c b/drivers/infiniband/core/ucma.c
index cb5b34c..49d94c1 100644 (file)
--- a/drivers/infiniband/core/ucma.c
+++ b/drivers/infiniband/core/ucma.c
@@ -1043,7 +1043,7 @@ static ssize_t ucma_notify(struct ucma_file *file, const char __user *inbuf,
 {
        struct rdma_ucm_notify cmd;
        struct ucma_context *ctx;
-       int ret;
+       int ret = -EINVAL;
 
        if (copy_from_user(&cmd, inbuf, sizeof(cmd)))
                return -EFAULT;
@@ -1052,7 +1052,9 @@ static ssize_t ucma_notify(struct ucma_file *file, const char __user *inbuf,
        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;
 }