[PATCH 3.16 094/366] RDMA/ucma: Don't allow setting RDMA_OPTION_IB_PATH without an RDMA device

[Ben Hutchings]

3.16.60-rc1 review patch.  If anyone has any objections, please let me know.

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

From: Roland Dreier <rol...@purestorage.com>

commit 8435168d50e66fa5eae01852769d20a36f9e5e83 upstream.

Check to make sure that ctx->cm_id->device is set before we use it.
Otherwise userspace can trigger a NULL dereference by doing
RDMA_USER_CM_CMD_SET_OPTION on an ID that is not bound to a device.

Reported-by: <syzbot+a67bc93e14682d92f...@syzkaller.appspotmail.com>
Signed-off-by: Roland Dreier <rol...@purestorage.com>
Signed-off-by: Jason Gunthorpe <j...@mellanox.com>
Signed-off-by: Ben Hutchings <b...@decadent.org.uk>
---
 drivers/infiniband/core/ucma.c | 3 +++
 1 file changed, 3 insertions(+)

--- a/drivers/infiniband/core/ucma.c
+++ b/drivers/infiniband/core/ucma.c
@@ -1142,6 +1142,9 @@ static int ucma_set_ib_path(struct ucma_
        if (!optlen)
                return -EINVAL;
 
+       if (!ctx->cm_id->device)
+               return -EINVAL;
+
        memset(&sa_path, 0, sizeof(sa_path));
        sa_path.vlan_id = 0xffff;