netdev - [PATCH v2 6/8] bpf: Leverage sockptr

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Date: Tue,  8 Aug 2023 06:40:46 -0700
From: Breno Leitao <leitao@...ian.org>
To: sdf@...gle.com,
	axboe@...nel.dk,
	asml.silence@...il.com,
	willemdebruijn.kernel@...il.com,
	Alexei Starovoitov <ast@...nel.org>,
	Daniel Borkmann <daniel@...earbox.net>,
	Andrii Nakryiko <andrii@...nel.org>,
	Martin KaFai Lau <martin.lau@...ux.dev>,
	Song Liu <song@...nel.org>,
	Yonghong Song <yhs@...com>,
	John Fastabend <john.fastabend@...il.com>,
	KP Singh <kpsingh@...nel.org>,
	Hao Luo <haoluo@...gle.com>,
	Jiri Olsa <jolsa@...nel.org>,
	"David S. Miller" <davem@...emloft.net>,
	Eric Dumazet <edumazet@...gle.com>,
	Jakub Kicinski <kuba@...nel.org>,
	Paolo Abeni <pabeni@...hat.com>
Cc: bpf@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	netdev@...r.kernel.org,
	io-uring@...r.kernel.org
Subject: [PATCH v2 6/8] bpf: Leverage sockptr_t in BPF setsockopt hook

Move BPF setsockopt hook (__cgroup_bpf_run_filter_setsockopt()) to use
sockptr instead of user pointers. This brings flexibility to the
function, since it could be called with userspace or kernel pointers.

This also aligns with the getsockopt() counterpart, which is now using
sockptr_t types.

Signed-off-by: Breno Leitao <leitao@...ian.org>
---
 include/linux/bpf-cgroup.h | 2 +-
 kernel/bpf/cgroup.c        | 5 +++--
 net/socket.c               | 2 +-
 3 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/include/linux/bpf-cgroup.h b/include/linux/bpf-cgroup.h
index d16cb99fd4f1..5e3419eb267a 100644
--- a/include/linux/bpf-cgroup.h
+++ b/include/linux/bpf-cgroup.h
@@ -137,7 +137,7 @@ int __cgroup_bpf_run_filter_sysctl(struct ctl_table_header *head,
 				   enum cgroup_bpf_attach_type atype);
 
 int __cgroup_bpf_run_filter_setsockopt(struct sock *sock, int *level,
-				       int *optname, char __user *optval,
+				       int *optname, sockptr_t optval,
 				       int *optlen, char **kernel_optval);
 
 int __cgroup_bpf_run_filter_getsockopt(struct sock *sk, int level,
diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c
index ebc8c58f7e46..f0dedd4f7f2e 100644
--- a/kernel/bpf/cgroup.c
+++ b/kernel/bpf/cgroup.c
@@ -1785,7 +1785,7 @@ static bool sockopt_buf_allocated(struct bpf_sockopt_kern *ctx,
 }
 
 int __cgroup_bpf_run_filter_setsockopt(struct sock *sk, int *level,
-				       int *optname, char __user *optval,
+				       int *optname, sockptr_t optval,
 				       int *optlen, char **kernel_optval)
 {
 	struct cgroup *cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data);
@@ -1808,7 +1808,8 @@ int __cgroup_bpf_run_filter_setsockopt(struct sock *sk, int *level,
 
 	ctx.optlen = *optlen;
 
-	if (copy_from_user(ctx.optval, optval, min(*optlen, max_optlen)) != 0) {
+	if (copy_from_sockptr(ctx.optval, optval,
+			      min(*optlen, max_optlen))) {
 		ret = -EFAULT;
 		goto out;
 	}
diff --git a/net/socket.c b/net/socket.c
index c686c6e89441..b7d22633995a 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -2241,7 +2241,7 @@ int __sys_setsockopt(int fd, int level, int optname, char __user *user_optval,
 
 	if (!in_compat_syscall())
 		err = BPF_CGROUP_RUN_PROG_SETSOCKOPT(sock->sk, &level, &optname,
-						     user_optval, &optlen,
+						     optval, &optlen,
 						     &kernel_optval);
 	if (err < 0)
 		goto out_put;
-- 
2.34.1