Re: [PATCH bpf-next v8 5/7] selftests/bpf: add bpf_icmp_send kfunc cgroup_skb IPv6 tests

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] Calling getsockname() with a struct sockaddr_in buffer on an IPv6 socket causes address truncation and relies on unsafe type punning.
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commit 89e403390c4ceaaf94ef22de532a6ce7e24b710b
Author: Mahe Tardy <mahe.tardy@gmail.com>

selftests/bpf: add bpf_icmp_send kfunc cgroup_skb IPv6 tests

This commit extends the existing cgroup_skb tests for the bpf_icmp_send
kfunc to include IPv6 support. It updates the test client and server
creation to handle both AF_INET and AF_INET6 families.

> diff --git a/tools/testing/selftests/bpf/prog_tests/icmp_send_kfunc.c b/tools/testing/selftests/bpf/prog_tests/icmp_send_kfunc.c
> --- a/tools/testing/selftests/bpf/prog_tests/icmp_send_kfunc.c
> +++ b/tools/testing/selftests/bpf/prog_tests/icmp_send_kfunc.c
[ ... ]
> -static void trigger_prog_read_icmp_errqueue(struct icmp_send *skel, int code)
> +static void trigger_prog_read_icmp_errqueue(struct icmp_send *skel, int code,
> +					    int af, const char *ip)
>  {
>  	int srv_fd = -1, client_fd = -1;
>  	struct sockaddr_in addr;
>  	socklen_t len = sizeof(addr);

[Severity: Medium]
Since this function now handles IPv6 sockets when af is AF_INET6, does using
a struct sockaddr_in buffer for getsockname() cause address truncation?

When getsockname() is called on an IPv6 socket, the kernel will attempt to
write a 28-byte struct sockaddr_in6, but it is constrained by the 16-byte
buffer size here. While extracting the port via addr.sin_port later in this
function coincidentally works because the port offset is the same in both
structures, should this use struct sockaddr_storage instead to safely
accommodate both IPv4 and IPv6 addresses?

> -	srv_fd = start_server(AF_INET, SOCK_STREAM, "127.0.0.1", 0, TIMEOUT_MS);
> +	srv_fd = start_server(af, SOCK_STREAM, ip, 0, TIMEOUT_MS);
>  	if (!ASSERT_OK_FD(srv_fd, "start_server"))
>  		return;

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Sashiko AI review · https://sashiko.dev/#/patchset/20260622120515.137082-1-mahe.tardy@gmail.com?part=5