| Message ID | 20171206202015.GA15636@embeddedor.com (mailing list archive) |
|---|---|
| State | Deferred |
| Headers | show |
On 2017년 12월 07일 05:20, Gustavo A. R. Silva wrote: > df->governor is being dereferenced before it is null checked, > hence there is a potential null pointer dereference. > > Notice that df->governor is being null checked at line 1004: > if (df->governor) {, which implies it might be null. > > Fix this by null checking df->governor before dereferencing it. > > Addresses-Coverity-ID: 1401988 ("Dereference before null check") > Fixes: bcf23c79c4e4 ("PM / devfreq: Fix available_governor sysfs") > Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com> > --- > drivers/devfreq/devfreq.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c > index 78fb496..14fe76b 100644 > --- a/drivers/devfreq/devfreq.c > +++ b/drivers/devfreq/devfreq.c > @@ -996,7 +996,8 @@ static ssize_t governor_store(struct device *dev, struct device_attribute *attr, > if (df->governor == governor) { > ret = 0; > goto out; > - } else if (df->governor->immutable || governor->immutable) { > + } else if ((df->governor && df->governor->immutable) || > + governor->immutable) { > ret = -EINVAL; > goto out; > } > Actually, df->governor would be never NULL because devfreq_add_device() initializes the ->governor always. But, governor_store() doesn't know it. So, looks good to me. Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com>
> df->governor is being dereferenced before it is null checked, > hence there is a potential null pointer dereference. > > Notice that df->governor is being null checked at line 1004: > if (df->governor) {, which implies it might be null. > > Fix this by null checking df->governor before dereferencing it. > > Addresses-Coverity-ID: 1401988 ("Dereference before null check") > Fixes: bcf23c79c4e4 ("PM / devfreq: Fix available_governor sysfs") > Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com> Acked-by: MyungJoo Ham <myungjoo.ham@samsung.com> Cheers, MyungJoo > --- > drivers/devfreq/devfreq.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c > index 78fb496..14fe76b 100644
Hi Chanwoo, Quoting Chanwoo Choi <cw00.choi@samsung.com>: > On 2017년 12월 07일 05:20, Gustavo A. R. Silva wrote: >> df->governor is being dereferenced before it is null checked, >> hence there is a potential null pointer dereference. >> >> Notice that df->governor is being null checked at line 1004: >> if (df->governor) {, which implies it might be null. >> >> Fix this by null checking df->governor before dereferencing it. >> >> Addresses-Coverity-ID: 1401988 ("Dereference before null check") >> Fixes: bcf23c79c4e4 ("PM / devfreq: Fix available_governor sysfs") >> Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com> >> --- >> drivers/devfreq/devfreq.c | 3 ++- >> 1 file changed, 2 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c >> index 78fb496..14fe76b 100644 >> --- a/drivers/devfreq/devfreq.c >> +++ b/drivers/devfreq/devfreq.c >> @@ -996,7 +996,8 @@ static ssize_t governor_store(struct device >> *dev, struct device_attribute *attr, >> if (df->governor == governor) { >> ret = 0; >> goto out; >> - } else if (df->governor->immutable || governor->immutable) { >> + } else if ((df->governor && df->governor->immutable) || >> + governor->immutable) { >> ret = -EINVAL; >> goto out; >> } >> > > Actually, df->governor would be never NULL because devfreq_add_device() > initializes the ->governor always. But, governor_store() doesn't know it. > I got it. > So, looks good to me. > Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com> > Thank you -- Gustavo A. R. Silva
Quoting MyungJoo Ham <myungjoo.ham@samsung.com>: >> df->governor is being dereferenced before it is null checked, >> hence there is a potential null pointer dereference. >> >> Notice that df->governor is being null checked at line 1004: >> if (df->governor) {, which implies it might be null. >> >> Fix this by null checking df->governor before dereferencing it. >> >> Addresses-Coverity-ID: 1401988 ("Dereference before null check") >> Fixes: bcf23c79c4e4 ("PM / devfreq: Fix available_governor sysfs") >> Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com> > > Acked-by: MyungJoo Ham <myungjoo.ham@samsung.com> > Thank you, MyungJoo -- Gustavo A. R. Silva
diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c index 78fb496..14fe76b 100644 --- a/drivers/devfreq/devfreq.c +++ b/drivers/devfreq/devfreq.c @@ -996,7 +996,8 @@ static ssize_t governor_store(struct device *dev, struct device_attribute *attr, if (df->governor == governor) { ret = 0; goto out; - } else if (df->governor->immutable || governor->immutable) { + } else if ((df->governor && df->governor->immutable) || + governor->immutable) { ret = -EINVAL; goto out; }
df->governor is being dereferenced before it is null checked, hence there is a potential null pointer dereference. Notice that df->governor is being null checked at line 1004: if (df->governor) {, which implies it might be null. Fix this by null checking df->governor before dereferencing it. Addresses-Coverity-ID: 1401988 ("Dereference before null check") Fixes: bcf23c79c4e4 ("PM / devfreq: Fix available_governor sysfs") Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com> --- drivers/devfreq/devfreq.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)