[PATCH 4.4 34/72] RDMA/ucma: Check that device exists prior to accessing it

From: Greg Kroah-Hartman
Date: Fri Apr 06 2018 - 09:30:42 EST


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

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

From: Leon Romanovsky <leonro@xxxxxxxxxxxx>

commit c8d3bcbfc5eab3f01cf373d039af725f3b488813 upstream.

Ensure that device exists prior to accessing its properties.

Reported-by: <syzbot+71655d44855ac3e76366@xxxxxxxxxxxxxxxxxxxxxxxxx>
Fixes: 75216638572f ("RDMA/cma: Export rdma cm interface to userspace")
Signed-off-by: Leon Romanovsky <leonro@xxxxxxxxxxxx>
Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
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
@@ -1316,7 +1316,7 @@ 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;
@@ -1325,7 +1325,9 @@ 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;
}