[PATCH net] ethtool: strset: Fix reply_size value

[PATCH net] ethtool: strset: Fix reply_size value

[Amit Cohen]

strset_reply_size() does not take into account the size required for the
'ETHTOOL_A_STRSET_STRINGSETS' nested attribute.
Since commit 4d1fb7cde0cc ("ethtool: add a stricter length check") this
results in the following warning in the kernel log:

ethnl cmd 1: calculated reply length 2236, but consumed 2240
WARNING: CPU: 2 PID: 30549 at net/ethtool/netlink.c:360 ethnl_default_doit+0x29f/0x310

Add the appropriate size to the calculation.

Fixes: 71921690f974 ("ethtool: provide string sets with STRSET_GET request")
Signed-off-by: Amit Cohen <amcohen@nvidia.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Tested-by: Ido Schimmel <idosch@nvidia.com>
---
 net/ethtool/strset.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/ethtool/strset.c b/net/ethtool/strset.c
index b3029fff715d..86dcb6b099b3 100644
--- a/net/ethtool/strset.c
+++ b/net/ethtool/strset.c
@@ -365,7 +365,7 @@ static int strset_reply_size(const struct ethnl_req_info *req_base,
 		len += ret;
 	}
 
-	return len;
+	return nla_total_size(len);
 }
 
 /* fill one string into reply */
-- 
2.31.1

Re: [PATCH net] ethtool: strset: Fix reply_size value

[Ido Schimmel]

On Thu, Jun 17, 2021 at 06:42:52PM +0300, Amit Cohen wrote:
> strset_reply_size() does not take into account the size required for the
> 'ETHTOOL_A_STRSET_STRINGSETS' nested attribute.
> Since commit 4d1fb7cde0cc ("ethtool: add a stricter length check") this
> results in the following warning in the kernel log:
> 
> ethnl cmd 1: calculated reply length 2236, but consumed 2240
> WARNING: CPU: 2 PID: 30549 at net/ethtool/netlink.c:360 ethnl_default_doit+0x29f/0x310
> 
> Add the appropriate size to the calculation.
> 
> Fixes: 71921690f974 ("ethtool: provide string sets with STRSET_GET request")
> Signed-off-by: Amit Cohen <amcohen@nvidia.com>
> Reviewed-by: Jiri Pirko <jiri@nvidia.com>
> Reviewed-by: Ido Schimmel <idosch@nvidia.com>
> Tested-by: Ido Schimmel <idosch@nvidia.com>

Ha, seems this is addressed by commit e175aef90269 ("ethtool: strset:
fix message length calculation") in net.git which actually motivated
commit 4d1fb7cde0cc ("ethtool: add a stricter length check").

The former is still not in net-next.git, which is why the warning is
triggered there.

The patch can be dropped.

Re: [PATCH net] ethtool: strset: Fix reply_size value

[Michal Kubecek]

On Thu, Jun 17, 2021 at 06:42:52PM +0300, Amit Cohen wrote:
> strset_reply_size() does not take into account the size required for the
> 'ETHTOOL_A_STRSET_STRINGSETS' nested attribute.
> Since commit 4d1fb7cde0cc ("ethtool: add a stricter length check") this
> results in the following warning in the kernel log:
> 
> ethnl cmd 1: calculated reply length 2236, but consumed 2240
> WARNING: CPU: 2 PID: 30549 at net/ethtool/netlink.c:360 ethnl_default_doit+0x29f/0x310
> 
> Add the appropriate size to the calculation.
> 
> Fixes: 71921690f974 ("ethtool: provide string sets with STRSET_GET request")
> Signed-off-by: Amit Cohen <amcohen@nvidia.com>
> Reviewed-by: Jiri Pirko <jiri@nvidia.com>
> Reviewed-by: Ido Schimmel <idosch@nvidia.com>
> Tested-by: Ido Schimmel <idosch@nvidia.com>
> ---
>  net/ethtool/strset.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/net/ethtool/strset.c b/net/ethtool/strset.c
> index b3029fff715d..86dcb6b099b3 100644
> --- a/net/ethtool/strset.c
> +++ b/net/ethtool/strset.c
> @@ -365,7 +365,7 @@ static int strset_reply_size(const struct ethnl_req_info *req_base,
>  		len += ret;
>  	}
>  
> -	return len;
> +	return nla_total_size(len);
>  }
>  
>  /* fill one string into reply */

I believe this issue has been already fixed in net tree by commit
e175aef90269 ("ethtool: strset: fix message length calculation") but as
this commit has not been merged into net-next yet, you could hit it with
the stricter check.

Michal

Re: [PATCH net] ethtool: strset: Fix reply_size value

[Ido Schimmel]

On Thu, Jun 17, 2021 at 06:29:23PM +0200, Michal Kubecek wrote:
> I believe this issue has been already fixed in net tree by commit
> e175aef90269 ("ethtool: strset: fix message length calculation") but as
> this commit has not been merged into net-next yet, you could hit it with
> the stricter check.

Yea. I reached the same conclusion :/

Re: [PATCH net] ethtool: strset: Fix reply_size value

[Jakub Kicinski]

On Thu, 17 Jun 2021 19:33:27 +0300 Ido Schimmel wrote:
> On Thu, Jun 17, 2021 at 06:29:23PM +0200, Michal Kubecek wrote:
> > I believe this issue has been already fixed in net tree by commit
> > e175aef90269 ("ethtool: strset: fix message length calculation") but as
> > this commit has not been merged into net-next yet, you could hit it with
> > the stricter check.  
> 
> Yea. I reached the same conclusion :/

Ah damn, I should have waited for the merge, sorry about that :S