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Subject[PATCH v2] regmap: potentially duplicate the name string stored in regmap
Date
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 <brgl@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
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