* [PATCH bpf] bpf: Return -EINVAL on calling bpf_setsockopt(TCP_SAVED_SYN)
@ 2022-10-25 11:22 Rongfeng Ji
2022-10-26 0:02 ` Martin KaFai Lau
0 siblings, 1 reply; 2+ messages in thread
From: Rongfeng Ji @ 2022-10-25 11:22 UTC (permalink / raw)
To: bpf; +Cc: martin.lau, ast, Rongfeng Ji
TCP_SAVED_SYN is not supported by do_tcp_setsockopt(), but it is not
rejected by sol_tcp_sockopt() during calling bpf_setsockopt(), which
results in returning -ENOPROTOOPT instead of common -EINVAL.
This patch fixes the issue.
Signed-off-by: Rongfeng Ji <SikoJobs@outlook.com>
---
net/core/filter.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/net/core/filter.c b/net/core/filter.c
index bb0136e7a8e4..42cd7ec8cc4c 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -5206,6 +5206,9 @@ static int sol_tcp_sockopt(struct sock *sk, int optname,
return do_tcp_getsockopt(sk, SOL_TCP, optname,
KERNEL_SOCKPTR(optval),
KERNEL_SOCKPTR(optlen));
+ } else {
+ if (optname == TCP_SAVED_SYN)
+ return -EINVAL;
}
return do_tcp_setsockopt(sk, SOL_TCP, optname,
--
2.30.2
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH bpf] bpf: Return -EINVAL on calling bpf_setsockopt(TCP_SAVED_SYN)
2022-10-25 11:22 [PATCH bpf] bpf: Return -EINVAL on calling bpf_setsockopt(TCP_SAVED_SYN) Rongfeng Ji
@ 2022-10-26 0:02 ` Martin KaFai Lau
0 siblings, 0 replies; 2+ messages in thread
From: Martin KaFai Lau @ 2022-10-26 0:02 UTC (permalink / raw)
To: Rongfeng Ji; +Cc: ast, bpf
On 10/25/22 4:22 AM, Rongfeng Ji wrote:
> TCP_SAVED_SYN is not supported by do_tcp_setsockopt(), but it is not
> rejected by sol_tcp_sockopt() during calling bpf_setsockopt(), which
> results in returning -ENOPROTOOPT instead of common -EINVAL.
>
> This patch fixes the issue.
>
> Signed-off-by: Rongfeng Ji <SikoJobs@outlook.com>
> ---
> net/core/filter.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/net/core/filter.c b/net/core/filter.c
> index bb0136e7a8e4..42cd7ec8cc4c 100644
> --- a/net/core/filter.c
> +++ b/net/core/filter.c
> @@ -5206,6 +5206,9 @@ static int sol_tcp_sockopt(struct sock *sk, int optname,
> return do_tcp_getsockopt(sk, SOL_TCP, optname,
> KERNEL_SOCKPTR(optval),
> KERNEL_SOCKPTR(optlen));
> + } else {
> + if (optname == TCP_SAVED_SYN)
> + return -EINVAL;
ENOPROTOOPT is fine and is better imo. man 7 setsockopt:
ENOPROTOOPT
The option is unknown at the level indicated.
It is why I did not single out the TCP_SAVED_SYN again to return -EINVAL.
I don't see how the bpf_prog would handle them differently (bpf prog does not
allow it -EINVAL or the underlying kernel's setsockopt does not know it
-ENOPROTOOPT). In general, the bpf_{get,set}sockopt caller has to be ready to
handle any errno from the kernel underlying {get,set}sockopt.
Also, some of the -EINVAL in bpf_{get,set}sockopt() is not the best one to
return. It is not very helpful for the bpf prog to figure out what is wrong.
They should be fixed in the future also.
^ permalink raw reply [flat|nested] 2+ messages in thread
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2022-10-25 11:22 [PATCH bpf] bpf: Return -EINVAL on calling bpf_setsockopt(TCP_SAVED_SYN) Rongfeng Ji
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