From: Eric Dumazet <edumazet@google.com>
To: Joe Damato <jdamato@fastly.com>
Cc: linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
dhowells@redhat.com, alexander@mihalicyn.com, leitao@debian.org,
wuyun.abel@bytedance.com, kuniyu@amazon.com, pabeni@redhat.com,
kuba@kernel.org, davem@davemloft.net
Subject: Re: [PATCH net-next] net: print error if SO_BUSY_POLL_BUDGET is large
Date: Thu, 25 Jan 2024 20:33:56 +0100 [thread overview]
Message-ID: <CANn89i+uXsdSVFiQT9fDfGw+h_5QOcuHwPdWi9J=5U6oLXkQTA@mail.gmail.com> (raw)
In-Reply-To: <20240125191840.6740-1-jdamato@fastly.com>
On Thu, Jan 25, 2024 at 8:18 PM Joe Damato <jdamato@fastly.com> wrote:
>
> When drivers call netif_napi_add_weight with a weight that is larger
> than NAPI_POLL_WEIGHT, the networking code allows the larger weight, but
> prints an error.
>
> Replicate this check for SO_BUSY_POLL_BUDGET; check if the user
> specified amount exceeds NAPI_POLL_WEIGHT, allow it anyway, but print an
> error.
>
> Signed-off-by: Joe Damato <jdamato@fastly.com>
> ---
> net/core/sock.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/net/core/sock.c b/net/core/sock.c
> index 158dbdebce6a..ed243bd0dd77 100644
> --- a/net/core/sock.c
> +++ b/net/core/sock.c
> @@ -1153,6 +1153,9 @@ int sk_setsockopt(struct sock *sk, int level, int optname,
> return -EPERM;
> if (val < 0 || val > U16_MAX)
> return -EINVAL;
> + if (val > NAPI_POLL_WEIGHT)
> + pr_err("SO_BUSY_POLL_BUDGET %u exceeds suggested maximum %u\n", val,
> + NAPI_POLL_WEIGHT);
> WRITE_ONCE(sk->sk_busy_poll_budget, val);
> return 0;
This is code run by privileged (CAP_NET_ADMIN) users,
please do not spam the console with such a message.
My point was : Do not allow an unpriv user to set an arbitrary value.
netif_napi_add_weight() is used from kernel drivers, we network
maintainers usually object
if a driver attempts to use a big value, at code review time.
next prev parent reply other threads:[~2024-01-25 19:34 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-01-25 19:18 [PATCH net-next] net: print error if SO_BUSY_POLL_BUDGET is large Joe Damato
2024-01-25 19:33 ` Eric Dumazet [this message]
2024-01-26 9:11 ` Breno Leitao
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