2022-03-05 20:29:38

by Tom Rix

Subject: [PATCH] net: rtnetlink: fix error handling in rtnl_fill_statsinfo()

From: Tom Rix <[email protected]>

The clang static analyzer reports this issue
rtnetlink.c:5481:2: warning: Undefined or garbage
value returned to caller
return err;
^~~~~~~~~~

There is a function level err variable, in the
list_for_each_entry_rcu block there is a shadow
err. Remove the shadow.

In the same block, the call to nla_nest_start_noflag()
can fail without setting an err. Set the err
to -EMSGSIZE.

Fixes: 216e690631f5 ("net: rtnetlink: rtnl_fill_statsinfo(): Permit non-EMSGSIZE error returns")
Signed-off-by: Tom Rix <[email protected]>
---
net/core/rtnetlink.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index a66b6761b88b1..a759f9e0a8476 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -5440,12 +5440,12 @@ static int rtnl_fill_statsinfo(struct sk_buff *skb, struct net_device *dev,
list_for_each_entry_rcu(af_ops, &rtnl_af_ops, list) {
if (af_ops->fill_stats_af) {
struct nlattr *af;
- int err;

af = nla_nest_start_noflag(skb,
af_ops->family);
if (!af) {
rcu_read_unlock();
+ err = -EMSGSIZE;
goto nla_put_failure;
}
err = af_ops->fill_stats_af(skb, dev);
--
2.26.3

2022-03-07 09:20:52

by Ido Schimmel

Subject: Re: [PATCH] net: rtnetlink: fix error handling in rtnl_fill_statsinfo()

On Sat, Mar 05, 2022 at 10:13:46AM -0800, [email protected] wrote:
> From: Tom Rix <[email protected]>
>
> The clang static analyzer reports this issue
> rtnetlink.c:5481:2: warning: Undefined or garbage
> value returned to caller
> return err;
> ^~~~~~~~~~
>
> There is a function level err variable, in the
> list_for_each_entry_rcu block there is a shadow
> err. Remove the shadow.
>
> In the same block, the call to nla_nest_start_noflag()
> can fail without setting an err. Set the err
> to -EMSGSIZE.
>
> Fixes: 216e690631f5 ("net: rtnetlink: rtnl_fill_statsinfo(): Permit non-EMSGSIZE error returns")
> Signed-off-by: Tom Rix <[email protected]>

For net-next:

Reviewed-by: Ido Schimmel <[email protected]>

Thanks

2022-03-07 10:36:58

by Petr Machata

Subject: Re: [PATCH] net: rtnetlink: fix error handling in rtnl_fill_statsinfo()

[email protected] writes:

> From: Tom Rix <[email protected]>
>
> The clang static analyzer reports this issue
> rtnetlink.c:5481:2: warning: Undefined or garbage
> value returned to caller
> return err;
> ^~~~~~~~~~
>
> There is a function level err variable, in the
> list_for_each_entry_rcu block there is a shadow
> err. Remove the shadow.
>
> In the same block, the call to nla_nest_start_noflag()
> can fail without setting an err. Set the err
> to -EMSGSIZE.
>
> Fixes: 216e690631f5 ("net: rtnetlink: rtnl_fill_statsinfo(): Permit non-EMSGSIZE error returns")
> Signed-off-by: Tom Rix <[email protected]>

Reviewed-by: Petr Machata <[email protected]>

Thanks!

2022-03-07 12:36:30

by patchwork-bot+netdevbpf

Subject: Re: [PATCH] net: rtnetlink: fix error handling in rtnl_fill_statsinfo()

Hello:

This patch was applied to netdev/net-next.git (master)
by David S. Miller <[email protected]>:

On Sat, 5 Mar 2022 10:13:46 -0800 you wrote:
> From: Tom Rix <[email protected]>
>
> The clang static analyzer reports this issue
> rtnetlink.c:5481:2: warning: Undefined or garbage
> value returned to caller
> return err;
> ^~~~~~~~~~
>
> [...]

Here is the summary with links:
- net: rtnetlink: fix error handling in rtnl_fill_statsinfo()
https://git.kernel.org/netdev/net-next/c/57d29a2935c9

You are awesome, thank you!
--
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html