[PATCH v2] regmap: potentially duplicate the name string stored in regmap

[Bartosz Golaszewski]

Currently we just copy over the pointer passed to regmap_init() in
the regmap config struct. To be on the safe side: duplicate the string
with kstrdup_const() so that if an unaware user passes an address to
a stack-allocated buffer, we won't crash.

Signed-off-by: Bartosz Golaszewski <b...@bgdev.pl>
---
v1 -> v2:
- drop the patches that were either applied or done by Mark
- fix an error path
- use kstrdup_const() instead of kstrdup() to avoid unnecessary memory
  allocations

 drivers/base/regmap/regmap.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index 16a66ba84aef..bd62600b40e4 100644
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -672,6 +672,14 @@ struct regmap *__regmap_init(struct device *dev,
                goto err;
        }
 
+       if (config->name) {
+               map->name = kstrdup_const(config->name, GFP_KERNEL);
+               if (!map->name) {
+                       ret = -ENOMEM;
+                       goto err_map;
+               }
+       }
+
        if (config->disable_locking) {
                map->lock = map->unlock = regmap_lock_unlock_none;
        } else if (config->lock && config->unlock) {
@@ -682,7 +690,7 @@ struct regmap *__regmap_init(struct device *dev,
                map->hwlock = hwspin_lock_request_specific(config->hwlock_id);
                if (!map->hwlock) {
                        ret = -ENXIO;
-                       goto err_map;
+                       goto err_name;
                }
 
                switch (config->hwlock_mode) {
@@ -762,7 +770,6 @@ struct regmap *__regmap_init(struct device *dev,
        map->volatile_reg = config->volatile_reg;
        map->precious_reg = config->precious_reg;
        map->cache_type = config->cache_type;
-       map->name = config->name;
 
        spin_lock_init(&map->async_lock);
        INIT_LIST_HEAD(&map->async_list);
@@ -1118,6 +1125,8 @@ struct regmap *__regmap_init(struct device *dev,
 err_hwlock:
        if (map->hwlock)
                hwspin_lock_free(map->hwlock);
+err_name:
+       kfree_const(map->name);
 err_map:
        kfree(map);
 err:
@@ -1307,6 +1316,7 @@ void regmap_exit(struct regmap *map)
        }
        if (map->hwlock)
                hwspin_lock_free(map->hwlock);
+       kfree_const(map->name);
        kfree(map);
 }
 EXPORT_SYMBOL_GPL(regmap_exit);
-- 
2.15.1