| Message ID | 20210427114950.12739-1-colin.king@canonical.com |
|---|---|
| State | New |
| Headers | show |
| Series | [next,V2] gpio: sim: Fix dereference of free'd pointer config | expand |
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 >
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 > >> > > > > >
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;