[PATCH net] netlink: fix a memory leak on error path

[PATCH net] netlink: fix a memory leak on error path

[Chengguang Xu]

In genl_register_family(), when idr_alloc() fails,
we forget to free family->attrbuf.

Note, some callers call genl_unregister_family() to clean up
on error path, it doesn't work because the family is inserted
to the global list in the nearly last step.

Fixes: 2ae0f17df1c ("genetlink: use idr to track families").
Signed-off-by: Chengguang Xu <cgxu519@gmx.com>
---
 net/netlink/genetlink.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c
index 25eeb6d2a75a..f0ec068e1d02 100644
--- a/net/netlink/genetlink.c
+++ b/net/netlink/genetlink.c
@@ -366,7 +366,7 @@ int genl_register_family(struct genl_family *family)
 			       start, end + 1, GFP_KERNEL);
 	if (family->id < 0) {
 		err = family->id;
-		goto errout_locked;
+		goto errout_free;
 	}

 	err = genl_validate_assign_mc_groups(family);
@@ -385,6 +385,7 @@ int genl_register_family(struct genl_family *family)

 errout_remove:
 	idr_remove(&genl_fam_idr, family->id);
+errout_free:
 	kfree(family->attrbuf);
 errout_locked:
 	genl_unlock_all();
--
2.20.1

Re: [PATCH net] netlink: fix a memory leak on error path

[Kirill Tkhai]

Hi, Chengguang,

On 22.03.2019 13:58, Chengguang Xu wrote:
> In genl_register_family(), when idr_alloc() fails,
> we forget to free family->attrbuf.
> 
> Note, some callers call genl_unregister_family() to clean up
> on error path, it doesn't work because the family is inserted
> to the global list in the nearly last step.
> 
> Fixes: 2ae0f17df1c ("genetlink: use idr to track families").
> Signed-off-by: Chengguang Xu <cgxu519@gmx.com>

have you seen https://patchwork.ozlabs.org/patch/1059834/ ?

Kirill
> ---
>  net/netlink/genetlink.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c
> index 25eeb6d2a75a..f0ec068e1d02 100644
> --- a/net/netlink/genetlink.c
> +++ b/net/netlink/genetlink.c
> @@ -366,7 +366,7 @@ int genl_register_family(struct genl_family *family)
>  			       start, end + 1, GFP_KERNEL);
>  	if (family->id < 0) {
>  		err = family->id;
> -		goto errout_locked;
> +		goto errout_free;
>  	}
> 
>  	err = genl_validate_assign_mc_groups(family);
> @@ -385,6 +385,7 @@ int genl_register_family(struct genl_family *family)
> 
>  errout_remove:
>  	idr_remove(&genl_fam_idr, family->id);
> +errout_free:
>  	kfree(family->attrbuf);
>  errout_locked:
>  	genl_unlock_all();
> --
> 2.20.1
> 

Re: [PATCH net] netlink: fix a memory leak on error path

[cgxu519]

On 3/22/19 7:03 PM, Kirill Tkhai wrote:
> Hi, Chengguang,
>
> On 22.03.2019 13:58, Chengguang Xu wrote:
>> In genl_register_family(), when idr_alloc() fails,
>> we forget to free family->attrbuf.
>>
>> Note, some callers call genl_unregister_family() to clean up
>> on error path, it doesn't work because the family is inserted
>> to the global list in the nearly last step.
>>
>> Fixes: 2ae0f17df1c ("genetlink: use idr to track families").
>> Signed-off-by: Chengguang Xu <cgxu519@gmx.com>
> have you seen https://patchwork.ozlabs.org/patch/1059834/ ?

Sorry, I didn't notice that because I'm mainly working on linus-tree.
Please just ignore this patch.

Thanks.

Re: [PATCH net] netlink: fix a memory leak on error path

[Kirill Tkhai]

On 25.03.2019 04:19, cgxu519 wrote:
> On 3/22/19 7:03 PM, Kirill Tkhai wrote:
>> Hi, Chengguang,
>>
>> On 22.03.2019 13:58, Chengguang Xu wrote:
>>> In genl_register_family(), when idr_alloc() fails,
>>> we forget to free family->attrbuf.
>>>
>>> Note, some callers call genl_unregister_family() to clean up
>>> on error path, it doesn't work because the family is inserted
>>> to the global list in the nearly last step.
>>>
>>> Fixes: 2ae0f17df1c ("genetlink: use idr to track families").
>>> Signed-off-by: Chengguang Xu <cgxu519@gmx.com>
>> have you seen https://patchwork.ozlabs.org/patch/1059834/ ?
> 
> Sorry, I didn't notice that because I'm mainly working on linus-tree.
> Please just ignore this patch.

Not a problem.

Some information about network development process you may find in

https://www.kernel.org/doc/Documentation/networking/netdev-FAQ.txt

Kirill