clk: check ops pointer on clock register

[ Upstream commit 29fd2a34ef8d863e48183bd473ba57c8d7839e25 ]

Nothing really prevents a provider from (trying to) register a clock
without providing the clock ops structure.

We do check the individual fields before using them, but not the
structure pointer itself. This may have the usual nasty consequences when
the pointer is dereferenced, most likely when checking one the field
during the initialization.

This is fixed by returning an error on clock register if the ops pointer
is NULL.

Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Signed-off-by: Michael Turquette <mturquette@baylibre.com>
Link: lkml.kernel.org/r/20171219083329.24746-1-jbrunet@baylibre.com
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index b56c11f51bafad32bafc7b5b9c7467e7cd16632b..12180049a42ae18740a2d37bf8510595c1a58d61 100644 (file)
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -2684,7 +2684,13 @@ struct clk *clk_register(struct device *dev, struct clk_hw *hw)
                ret = -ENOMEM;
                goto fail_name;
        }
+
+       if (WARN_ON(!hw->init->ops)) {
+               ret = -EINVAL;
+               goto fail_ops;
+       }
        core->ops = hw->init->ops;
+
        if (dev && pm_runtime_enabled(dev))
                core->dev = dev;
        if (dev && dev->driver)
@@ -2746,6 +2752,7 @@ fail_parent_names_copy:
                kfree_const(core->parent_names[i]);
        kfree(core->parent_names);
 fail_parent_names:
+fail_ops:
        kfree_const(core->name);
 fail_name:
        kfree(core);