2022-12-04 03:02:24

by Jinjie Ruan

Subject: [PATCH] power: supply: fix null pointer dereferencing in power_supply_get_battery_info

when kmalloc() fail to allocate memory in kasprintf(), propname
will be NULL, strcmp() called by of_get_property() will cause
null pointer dereference.

So directly return ENOMEM, if kasprintf() return NULL pointer.

Fixes: 3afb50d7125b ("power: supply: core: Add some helpers to use the battery OCV capacity table")
Signed-off-by: ruanjinjie <[email protected]>
---
drivers/power/supply/power_supply_core.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/drivers/power/supply/power_supply_core.c b/drivers/power/supply/power_supply_core.c
index 4b5fb172fa99..2fd6ab7a4471 100644
--- a/drivers/power/supply/power_supply_core.c
+++ b/drivers/power/supply/power_supply_core.c
@@ -750,6 +750,8 @@ int power_supply_get_battery_info(struct power_supply *psy,
int i, tab_len, size;

propname = kasprintf(GFP_KERNEL, "ocv-capacity-table-%d", index);
+ if (!propname)
+ return -ENOMEM;
list = of_get_property(battery_np, propname, &size);
if (!list || !size) {
dev_err(&psy->dev, "failed to get %s\n", propname);
--
2.25.1

2022-12-05 07:50:28

by Baolin Wang

Subject: Re: [PATCH] power: supply: fix null pointer dereferencing in power_supply_get_battery_info

Hi,

On 12/4/2022 10:38 AM, ruanjinjie wrote:
> when kmalloc() fail to allocate memory in kasprintf(), propname
> will be NULL, strcmp() called by of_get_property() will cause
> null pointer dereference.
>
> So directly return ENOMEM, if kasprintf() return NULL pointer.
>
> Fixes: 3afb50d7125b ("power: supply: core: Add some helpers to use the battery OCV capacity table")
> Signed-off-by: ruanjinjie <[email protected]>
> ---
> drivers/power/supply/power_supply_core.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/drivers/power/supply/power_supply_core.c b/drivers/power/supply/power_supply_core.c
> index 4b5fb172fa99..2fd6ab7a4471 100644
> --- a/drivers/power/supply/power_supply_core.c
> +++ b/drivers/power/supply/power_supply_core.c
> @@ -750,6 +750,8 @@ int power_supply_get_battery_info(struct power_supply *psy,
> int i, tab_len, size;
>
> propname = kasprintf(GFP_KERNEL, "ocv-capacity-table-%d", index);
> + if (!propname)
> + return -ENOMEM;

Please read the code carefully, you can not just return error number
without releasing resource.

> list = of_get_property(battery_np, propname, &size);
> if (!list || !size) {
> dev_err(&psy->dev, "failed to get %s\n", propname);