* [PATCH][next][V2] gpio: sim: Fix dereference of free'd pointer config
@ 2021-04-27 11:49 Colin King
2021-04-27 12:11 ` Andy Shevchenko
0 siblings, 1 reply; 4+ messages in thread
From: Colin King @ 2021-04-27 11:49 UTC (permalink / raw)
To: Linus Walleij, Bartosz Golaszewski, Andy Shevchenko, linux-gpio
Cc: kernel-janitors, linux-kernel
From: Colin Ian King <colin.king@canonical.com>
The error return of config->id dereferences the kfree'd object config.
Fix this by using a temporary variable for the id to avoid this issue.
Addresses-Coverity: ("Read from pointer aftyer free")
Fixes: a49d14276ac4 ("gpio: sim: allocate IDA numbers earlier")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
V2: Don't make id local to the if statement to improve coding style.
Thanks to Bartosz Golaszewski for this improvement suggestion.
---
drivers/gpio/gpio-sim.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/drivers/gpio/gpio-sim.c b/drivers/gpio/gpio-sim.c
index 2e2e6399e453..b21541c0b700 100644
--- a/drivers/gpio/gpio-sim.c
+++ b/drivers/gpio/gpio-sim.c
@@ -744,20 +744,22 @@ static struct config_item *
gpio_sim_config_make_item(struct config_group *group, const char *name)
{
struct gpio_sim_chip_config *config;
+ int id;
config = kzalloc(sizeof(*config), GFP_KERNEL);
if (!config)
return ERR_PTR(-ENOMEM);
- config->id = ida_alloc(&gpio_sim_ida, GFP_KERNEL);
- if (config->id < 0) {
+ id = ida_alloc(&gpio_sim_ida, GFP_KERNEL);
+ if (id < 0) {
kfree(config);
- return ERR_PTR(config->id);
+ return ERR_PTR(id);
}
config_item_init_type_name(&config->item, name,
&gpio_sim_chip_config_type);
config->num_lines = 1;
+ config->id = id;
mutex_init(&config->lock);
return &config->item;
--
2.30.2
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH][next][V2] gpio: sim: Fix dereference of free'd pointer config
2021-04-27 11:49 [PATCH][next][V2] gpio: sim: Fix dereference of free'd pointer config Colin King
@ 2021-04-27 12:11 ` Andy Shevchenko
2021-04-27 12:20 ` Colin Ian King
0 siblings, 1 reply; 4+ messages in thread
From: Andy Shevchenko @ 2021-04-27 12:11 UTC (permalink / raw)
To: Colin King
Cc: Linus Walleij, Bartosz Golaszewski, open list:GPIO SUBSYSTEM,
kernel-janitors, Linux Kernel Mailing List
On Tue, Apr 27, 2021 at 2:49 PM Colin King <colin.king@canonical.com> wrote:
>
> From: Colin Ian King <colin.king@canonical.com>
>
> The error return of config->id dereferences the kfree'd object config.
> Fix this by using a temporary variable for the id to avoid this issue.
Thanks!
I'm wondering how I missed this... Nevertheless
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
> Addresses-Coverity: ("Read from pointer aftyer free")
after
> Fixes: a49d14276ac4 ("gpio: sim: allocate IDA numbers earlier")
> Signed-off-by: Colin Ian King <colin.king@canonical.com>
> ---
> V2: Don't make id local to the if statement to improve coding style.
> Thanks to Bartosz Golaszewski for this improvement suggestion.
> ---
> drivers/gpio/gpio-sim.c | 8 +++++---
> 1 file changed, 5 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpio/gpio-sim.c b/drivers/gpio/gpio-sim.c
> index 2e2e6399e453..b21541c0b700 100644
> --- a/drivers/gpio/gpio-sim.c
> +++ b/drivers/gpio/gpio-sim.c
> @@ -744,20 +744,22 @@ static struct config_item *
> gpio_sim_config_make_item(struct config_group *group, const char *name)
> {
> struct gpio_sim_chip_config *config;
> + int id;
>
> config = kzalloc(sizeof(*config), GFP_KERNEL);
> if (!config)
> return ERR_PTR(-ENOMEM);
>
> - config->id = ida_alloc(&gpio_sim_ida, GFP_KERNEL);
> - if (config->id < 0) {
> + id = ida_alloc(&gpio_sim_ida, GFP_KERNEL);
> + if (id < 0) {
> kfree(config);
> - return ERR_PTR(config->id);
> + return ERR_PTR(id);
> }
>
> config_item_init_type_name(&config->item, name,
> &gpio_sim_chip_config_type);
> config->num_lines = 1;
> + config->id = id;
> mutex_init(&config->lock);
>
> return &config->item;
> --
> 2.30.2
>
--
With Best Regards,
Andy Shevchenko
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH][next][V2] gpio: sim: Fix dereference of free'd pointer config
2021-04-27 12:11 ` Andy Shevchenko
@ 2021-04-27 12:20 ` Colin Ian King
2021-04-27 12:57 ` Bartosz Golaszewski
0 siblings, 1 reply; 4+ messages in thread
From: Colin Ian King @ 2021-04-27 12:20 UTC (permalink / raw)
To: Andy Shevchenko
Cc: Linus Walleij, Bartosz Golaszewski, open list:GPIO SUBSYSTEM,
kernel-janitors, Linux Kernel Mailing List
On 27/04/2021 13:11, Andy Shevchenko wrote:
> On Tue, Apr 27, 2021 at 2:49 PM Colin King <colin.king@canonical.com> wrote:
>>
>> From: Colin Ian King <colin.king@canonical.com>
>>
>> The error return of config->id dereferences the kfree'd object config.
>> Fix this by using a temporary variable for the id to avoid this issue.
>
> Thanks!
> I'm wondering how I missed this... Nevertheless
>
> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
>
>> Addresses-Coverity: ("Read from pointer aftyer free")
>
> after
>
Can that be fixed before applying rather me sending a V3?
>> Fixes: a49d14276ac4 ("gpio: sim: allocate IDA numbers earlier")
>> Signed-off-by: Colin Ian King <colin.king@canonical.com>
>> ---
>> V2: Don't make id local to the if statement to improve coding style.
>> Thanks to Bartosz Golaszewski for this improvement suggestion.
>> ---
>> drivers/gpio/gpio-sim.c | 8 +++++---
>> 1 file changed, 5 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/gpio/gpio-sim.c b/drivers/gpio/gpio-sim.c
>> index 2e2e6399e453..b21541c0b700 100644
>> --- a/drivers/gpio/gpio-sim.c
>> +++ b/drivers/gpio/gpio-sim.c
>> @@ -744,20 +744,22 @@ static struct config_item *
>> gpio_sim_config_make_item(struct config_group *group, const char *name)
>> {
>> struct gpio_sim_chip_config *config;
>> + int id;
>>
>> config = kzalloc(sizeof(*config), GFP_KERNEL);
>> if (!config)
>> return ERR_PTR(-ENOMEM);
>>
>> - config->id = ida_alloc(&gpio_sim_ida, GFP_KERNEL);
>> - if (config->id < 0) {
>> + id = ida_alloc(&gpio_sim_ida, GFP_KERNEL);
>> + if (id < 0) {
>> kfree(config);
>> - return ERR_PTR(config->id);
>> + return ERR_PTR(id);
>> }
>>
>> config_item_init_type_name(&config->item, name,
>> &gpio_sim_chip_config_type);
>> config->num_lines = 1;
>> + config->id = id;
>> mutex_init(&config->lock);
>>
>> return &config->item;
>> --
>> 2.30.2
>>
>
>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH][next][V2] gpio: sim: Fix dereference of free'd pointer config
2021-04-27 12:20 ` Colin Ian King
@ 2021-04-27 12:57 ` Bartosz Golaszewski
0 siblings, 0 replies; 4+ messages in thread
From: Bartosz Golaszewski @ 2021-04-27 12:57 UTC (permalink / raw)
To: Colin Ian King
Cc: Andy Shevchenko, Linus Walleij, open list:GPIO SUBSYSTEM,
kernel-janitors, Linux Kernel Mailing List
On Tue, Apr 27, 2021 at 2:20 PM Colin Ian King <colin.king@canonical.com> wrote:
>
> On 27/04/2021 13:11, Andy Shevchenko wrote:
> > On Tue, Apr 27, 2021 at 2:49 PM Colin King <colin.king@canonical.com> wrote:
> >>
> >> From: Colin Ian King <colin.king@canonical.com>
> >>
> >> The error return of config->id dereferences the kfree'd object config.
> >> Fix this by using a temporary variable for the id to avoid this issue.
> >
> > Thanks!
> > I'm wondering how I missed this... Nevertheless
> >
> > Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
> >
> >> Addresses-Coverity: ("Read from pointer aftyer free")
> >
> > after
> >
>
> Can that be fixed before applying rather me sending a V3?
>
No need, I'll add it and apply right away.
Bartosz
> >> Fixes: a49d14276ac4 ("gpio: sim: allocate IDA numbers earlier")
> >> Signed-off-by: Colin Ian King <colin.king@canonical.com>
> >> ---
> >> V2: Don't make id local to the if statement to improve coding style.
> >> Thanks to Bartosz Golaszewski for this improvement suggestion.
> >> ---
> >> drivers/gpio/gpio-sim.c | 8 +++++---
> >> 1 file changed, 5 insertions(+), 3 deletions(-)
> >>
> >> diff --git a/drivers/gpio/gpio-sim.c b/drivers/gpio/gpio-sim.c
> >> index 2e2e6399e453..b21541c0b700 100644
> >> --- a/drivers/gpio/gpio-sim.c
> >> +++ b/drivers/gpio/gpio-sim.c
> >> @@ -744,20 +744,22 @@ static struct config_item *
> >> gpio_sim_config_make_item(struct config_group *group, const char *name)
> >> {
> >> struct gpio_sim_chip_config *config;
> >> + int id;
> >>
> >> config = kzalloc(sizeof(*config), GFP_KERNEL);
> >> if (!config)
> >> return ERR_PTR(-ENOMEM);
> >>
> >> - config->id = ida_alloc(&gpio_sim_ida, GFP_KERNEL);
> >> - if (config->id < 0) {
> >> + id = ida_alloc(&gpio_sim_ida, GFP_KERNEL);
> >> + if (id < 0) {
> >> kfree(config);
> >> - return ERR_PTR(config->id);
> >> + return ERR_PTR(id);
> >> }
> >>
> >> config_item_init_type_name(&config->item, name,
> >> &gpio_sim_chip_config_type);
> >> config->num_lines = 1;
> >> + config->id = id;
> >> mutex_init(&config->lock);
> >>
> >> return &config->item;
> >> --
> >> 2.30.2
> >>
> >
> >
>
^ permalink raw reply [flat|nested] 4+ messages in thread
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2021-04-27 11:49 [PATCH][next][V2] gpio: sim: Fix dereference of free'd pointer config Colin King
2021-04-27 12:11 ` Andy Shevchenko
2021-04-27 12:20 ` Colin Ian King
2021-04-27 12:57 ` Bartosz Golaszewski
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