Re: [PATCH bpf-next v7 5/7] selftests/bpf: add bpf_icmp_send kfunc cgroup_skb IPv6 tests

[Mahe Tardy <mahe.tardy@gmail.com>]

On Tue, May 26, 2026 at 07:32:48PM +0000, sashiko-bot@kernel.org wrote:
> Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
> - [Medium] Type confusion and address truncation in getsockname() due to using struct sockaddr_in for IPv6 addresses.
> --
> 
> commit 0cc9d08ecac1ed3d21b7e5cbf50d68e27cb610de
> Author: Mahe Tardy <mahe.tardy@gmail.com>
> 
> selftests/bpf: add bpf_icmp_send kfunc cgroup_skb IPv6 tests
> 
> This test extends the existing cgroup_skb tests for the bpf_icmp_send
> kfunc by adding IPv6 support.
> 
> > diff --git a/tools/testing/selftests/bpf/prog_tests/icmp_send_kfunc.c b/tools/testing/selftests/bpf/prog_tests/icmp_send_kfunc.c
> > index 0dc6b6ceafb4a..1d6900d6a8f8c 100644
> > --- a/tools/testing/selftests/bpf/prog_tests/icmp_send_kfunc.c
> > +++ b/tools/testing/selftests/bpf/prog_tests/icmp_send_kfunc.c
> 
> [ ... ]
> 
> > @@ -79,14 +94,15 @@ static void read_icmp_errqueue(int sockfd, int expected_code)
> >  	ASSERT_FAIL("no IP_RECVERR/IPV6_RECVERR control message found");
> >  }
> >  
> > -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);
> >  
> > -	srv_fd = start_server(AF_INET, SOCK_STREAM, "127.0.0.1", 0, TIMEOUT_MS);
> > -	if (!ASSERT_GE(srv_fd, 0, "start_server"))
> > +	srv_fd = start_server(af, SOCK_STREAM, ip, 0, TIMEOUT_MS);
> > +	if (!ASSERT_OK_FD(srv_fd, "start_server"))
> >  		return;
> >  
> >  	if (getsockname(srv_fd, (struct sockaddr *)&addr, &len)) {
> > @@ -94,6 +110,8 @@ static void trigger_prog_read_icmp_errqueue(struct icmp_send *skel, int code)
> >  		return;
> >  	}
> >  	skel->bss->server_port = ntohs(addr.sin_port);
> 
> [Severity: Medium]
> When af is AF_INET6, does this cause an address truncation in getsockname()
> since addr is defined as struct sockaddr_in?
> 
> For an IPv6 socket, getsockname() requires struct sockaddr_in6 which is
> larger than struct sockaddr_in. While reading addr.sin_port happens to map
> to the same memory offset as sin6_port, could this lead to type confusion
> if the address fields are ever used?
> 
> Would it be safer to use struct sockaddr_storage here to ensure enough space
> for either address family, similar to what is used in connect_to_fd_nonblock()?

I already replied many times to this point, I don't think that's a
problem here.

> 
> -- 
> Sashiko AI review · https://sashiko.dev/#/patchset/20260526153708.279717-1-mahe.tardy@gmail.com?part=5