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[PATCH -next] selinux: Fix memleak in security_read_state_kernel

Xiu Jianfeng posted 1 patch 3 years, 10 months ago 
security/selinux/ss/services.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
[PATCH -next] selinux: Fix memleak in security_read_state_kernel
Posted by Xiu Jianfeng 3 years, 10 months ago 
In this function, it directly returns the result of __security_read_policy
without freeing the allocated memory in *data, cause memory leak issue,
so free the memory if __security_read_policy failed.

Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com>
---
 security/selinux/ss/services.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c
index 69b2734311a6..fe5fcf571c56 100644
--- a/security/selinux/ss/services.c
+++ b/security/selinux/ss/services.c
@@ -4048,6 +4048,7 @@ int security_read_policy(struct selinux_state *state,
 int security_read_state_kernel(struct selinux_state *state,
 			       void **data, size_t *len)
 {
+	int err;
 	struct selinux_policy *policy;
 
 	policy = rcu_dereference_protected(
@@ -4060,5 +4061,11 @@ int security_read_state_kernel(struct selinux_state *state,
 	if (!*data)
 		return -ENOMEM;
 
-	return __security_read_policy(policy, *data, len);
+	err = __security_read_policy(policy, *data, len);
+	if (err) {
+		vfree(*data);
+		*data = NULL;
+		*len = 0;
+	}
+	return err;
 }
-- 
2.17.1
Re: [PATCH -next] selinux: Fix memleak in security_read_state_kernel
Posted by Ondrej Mosnacek 3 years, 10 months ago 
On Mon, Jun 13, 2022 at 4:02 PM Xiu Jianfeng <xiujianfeng@huawei.com> wrote:
> In this function, it directly returns the result of __security_read_policy
> without freeing the allocated memory in *data, cause memory leak issue,
> so free the memory if __security_read_policy failed.
>
> Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com>
> ---
>  security/selinux/ss/services.c | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c
> index 69b2734311a6..fe5fcf571c56 100644
> --- a/security/selinux/ss/services.c
> +++ b/security/selinux/ss/services.c
> @@ -4048,6 +4048,7 @@ int security_read_policy(struct selinux_state *state,
>  int security_read_state_kernel(struct selinux_state *state,
>                                void **data, size_t *len)
>  {
> +       int err;
>         struct selinux_policy *policy;
>
>         policy = rcu_dereference_protected(
> @@ -4060,5 +4061,11 @@ int security_read_state_kernel(struct selinux_state *state,
>         if (!*data)
>                 return -ENOMEM;
>
> -       return __security_read_policy(policy, *data, len);
> +       err = __security_read_policy(policy, *data, len);
> +       if (err) {
> +               vfree(*data);
> +               *data = NULL;
> +               *len = 0;
> +       }
> +       return err;
>  }
> --
> 2.17.1
>

security_read_policy() defined a few lines above has the same pattern
(just with vmalloc_user() in place of vmalloc()). Would you like to
send another patch to fix that function as well?

-- 
Ondrej Mosnacek
Software Engineer, Linux Security - SELinux kernel
Red Hat, Inc.
Re: [PATCH -next] selinux: Fix memleak in security_read_state_kernel
Posted by xiujianfeng 3 years, 10 months ago 
在 2022/6/14 20:57, Ondrej Mosnacek 写道:
> On Mon, Jun 13, 2022 at 4:02 PM Xiu Jianfeng <xiujianfeng@huawei.com> wrote:
>> In this function, it directly returns the result of __security_read_policy
>> without freeing the allocated memory in *data, cause memory leak issue,
>> so free the memory if __security_read_policy failed.
>>
>> Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com>
>> ---
>>   security/selinux/ss/services.c | 9 ++++++++-
>>   1 file changed, 8 insertions(+), 1 deletion(-)
>>
>> diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c
>> index 69b2734311a6..fe5fcf571c56 100644
>> --- a/security/selinux/ss/services.c
>> +++ b/security/selinux/ss/services.c
>> @@ -4048,6 +4048,7 @@ int security_read_policy(struct selinux_state *state,
>>   int security_read_state_kernel(struct selinux_state *state,
>>                                 void **data, size_t *len)
>>   {
>> +       int err;
>>          struct selinux_policy *policy;
>>
>>          policy = rcu_dereference_protected(
>> @@ -4060,5 +4061,11 @@ int security_read_state_kernel(struct selinux_state *state,
>>          if (!*data)
>>                  return -ENOMEM;
>>
>> -       return __security_read_policy(policy, *data, len);
>> +       err = __security_read_policy(policy, *data, len);
>> +       if (err) {
>> +               vfree(*data);
>> +               *data = NULL;
>> +               *len = 0;
>> +       }
>> +       return err;
>>   }
>> --
>> 2.17.1
>>
> security_read_policy() defined a few lines above has the same pattern
> (just with vmalloc_user() in place of vmalloc()). Would you like to
> send another patch to fix that function as well?
No problem, patch already sent.
>
Re: [PATCH -next] selinux: Fix memleak in security_read_state_kernel
Posted by Ondrej Mosnacek 3 years, 10 months ago 
On Tue, Jun 14, 2022 at 3:35 PM xiujianfeng <xiujianfeng@huawei.com> wrote:
>
>
> 在 2022/6/14 20:57, Ondrej Mosnacek 写道:
> > On Mon, Jun 13, 2022 at 4:02 PM Xiu Jianfeng <xiujianfeng@huawei.com> wrote:
> >> In this function, it directly returns the result of __security_read_policy
> >> without freeing the allocated memory in *data, cause memory leak issue,
> >> so free the memory if __security_read_policy failed.
> >>
> >> Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com>
> >> ---
> >>   security/selinux/ss/services.c | 9 ++++++++-
> >>   1 file changed, 8 insertions(+), 1 deletion(-)
> >>
> >> diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c
> >> index 69b2734311a6..fe5fcf571c56 100644
> >> --- a/security/selinux/ss/services.c
> >> +++ b/security/selinux/ss/services.c
> >> @@ -4048,6 +4048,7 @@ int security_read_policy(struct selinux_state *state,
> >>   int security_read_state_kernel(struct selinux_state *state,
> >>                                 void **data, size_t *len)
> >>   {
> >> +       int err;
> >>          struct selinux_policy *policy;
> >>
> >>          policy = rcu_dereference_protected(
> >> @@ -4060,5 +4061,11 @@ int security_read_state_kernel(struct selinux_state *state,
> >>          if (!*data)
> >>                  return -ENOMEM;
> >>
> >> -       return __security_read_policy(policy, *data, len);
> >> +       err = __security_read_policy(policy, *data, len);
> >> +       if (err) {
> >> +               vfree(*data);
> >> +               *data = NULL;
> >> +               *len = 0;
> >> +       }
> >> +       return err;
> >>   }
> >> --
> >> 2.17.1
> >>
> > security_read_policy() defined a few lines above has the same pattern
> > (just with vmalloc_user() in place of vmalloc()). Would you like to
> > send another patch to fix that function as well?
> No problem, patch already sent.

Wow, you're fast :) Thanks!

-- 
Ondrej Mosnacek
Software Engineer, Linux Security - SELinux kernel
Red Hat, Inc.
Re: [PATCH -next] selinux: Fix memleak in security_read_state_kernel
Posted by Paul Moore 3 years, 10 months ago 
On Mon, Jun 13, 2022 at 10:01 AM Xiu Jianfeng <xiujianfeng@huawei.com> wrote:
>
> In this function, it directly returns the result of __security_read_policy
> without freeing the allocated memory in *data, cause memory leak issue,
> so free the memory if __security_read_policy failed.
>
> Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com>
> ---
>  security/selinux/ss/services.c | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)

Merged into selinux/next, thanks.

-- 
paul-moore.com

Patchew 2.1-devel-ea86937

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