[PATCH v4 04/10] net/socket: Break down __sys_getsockopt

Breno Leitao
2023-09-04T16:25:39Z

Split __sys_getsockopt() into two functions by removing the core
logic into a sub-function (do_sock_getsockopt()). This will avoid
code duplication when doing the same operation in other callers, for
instance.

do_sock_getsockopt() will be called by io_uring getsockopt() command
operation in the following patch.

The same was done for the setsockopt pair.

Suggested-by: Martin KaFai Lau <martin.lau@linux.dev>
Signed-off-by: Breno Leitao <leitao@debian.org>
---
include/linux/bpf-cgroup.h | 2 +-
include/net/sock.h | 2 ++
net/core/sock.c | 8 -----
net/socket.c | 62 ++++++++++++++++++++++++--------------
4 files changed, 42 insertions(+), 32 deletions(-)

diff --git a/include/linux/bpf-cgroup.h b/include/linux/bpf-cgroup.h
index cecfe8c99f28..ffaca1ab5e8d 100644
--- a/include/linux/bpf-cgroup.h
+++ b/include/linux/bpf-cgroup.h
@@ -378,7 +378,7 @@ static inline bool cgroup_bpf_sock_enabled(struct sock *sk,
({ \
int __ret = 0; \
if (cgroup_bpf_enabled(CGROUP_GETSOCKOPT)) \
- get_user(__ret, optlen); \
+ copy_from_sockptr(&__ret, optlen, sizeof(int)); \
__ret; \
})

diff --git a/include/net/sock.h b/include/net/sock.h
index b059f9272303..c0185121efe4 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -1863,6 +1863,8 @@ int sock_setsockopt(struct socket *sock, int level, int op,
sockptr_t optval, unsigned int optlen);
int do_sock_setsockopt(struct socket *sock, bool compat, int level,
int optname, sockptr_t optval, int optlen);
+int do_sock_getsockopt(struct socket *sock, bool compat, int level,
+ int optname, sockptr_t optval, sockptr_t optlen);

int sk_getsockopt(struct sock *sk, int level, int optname,
sockptr_t optval, sockptr_t optlen);
diff --git a/net/core/sock.c b/net/core/sock.c
index 666a17cab4f5..cf15394ed664 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -2009,14 +2009,6 @@ int sk_getsockopt(struct sock *sk, int level, int optname,
return 0;
}

-int sock_getsockopt(struct socket *sock, int level, int optname,
- char __user *optval, int __user *optlen)
-{
- return sk_getsockopt(sock->sk, level, optname,
- USER_SOCKPTR(optval),
- USER_SOCKPTR(optlen));
-}
-
/*
* Initialize an sk_lock.
*
diff --git a/net/socket.c b/net/socket.c
index 3bf29a27653f..c79d2b2b902e 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -2332,6 +2332,42 @@ SYSCALL_DEFINE5(setsockopt, int, fd, int, level, int, optname,
INDIRECT_CALLABLE_DECLARE(bool tcp_bpf_bypass_getsockopt(int level,
int optname));

+int do_sock_getsockopt(struct socket *sock, bool compat, int level,
+ int optname, sockptr_t optval, sockptr_t optlen)
+{
+ int max_optlen __maybe_unused;
+ const struct proto_ops *ops;
+ int err;
+
+ err = security_socket_getsockopt(sock, level, optname);
+ if (err)
+ return err;
+
+ ops = READ_ONCE(sock->ops);
+ if (level == SOL_SOCKET) {
+ err = sk_getsockopt(sock->sk, level, optname, optval, optlen);
+ } else if (unlikely(!ops->getsockopt)) {
+ err = -EOPNOTSUPP;
+ } else {
+ if (WARN_ONCE(optval.is_kernel || optlen.is_kernel,
+ "Invalid argument type"))
+ return -EOPNOTSUPP;
+
+ err = ops->getsockopt(sock, level, optname, optval.user,
+ optlen.user);
+ }
+
+ if (!compat) {
+ max_optlen = BPF_CGROUP_GETSOCKOPT_MAX_OPTLEN(optlen);
+ err = BPF_CGROUP_RUN_PROG_GETSOCKOPT(sock->sk, level, optname,
+ optval, optlen, max_optlen,
+ err);
+ }
+
+ return err;
+}
+EXPORT_SYMBOL(do_sock_getsockopt);
+
/*
* Get a socket option. Because we don't know the option lengths we have
* to pass a user mode parameter for the protocols to sort out.
@@ -2339,37 +2375,17 @@ INDIRECT_CALLABLE_DECLARE(bool tcp_bpf_bypass_getsockopt(int level,
int __sys_getsockopt(int fd, int level, int optname, char __user *optval,
int __user *optlen)
{
- int max_optlen __maybe_unused;
- const struct proto_ops *ops;
int err, fput_needed;
+ bool compat = in_compat_syscall();
struct socket *sock;

sock = sockfd_lookup_light(fd, &err, &fput_needed);
if (!sock)
return err;

- err = security_socket_getsockopt(sock, level, optname);
- if (err)
- goto out_put;
-
- if (!in_compat_syscall())
- max_optlen = BPF_CGROUP_GETSOCKOPT_MAX_OPTLEN(optlen);
+ err = do_sock_getsockopt(sock, compat, level, optname,
+ USER_SOCKPTR(optval), USER_SOCKPTR(optlen));

- ops = READ_ONCE(sock->ops);
- if (level == SOL_SOCKET)
- err = sock_getsockopt(sock, level, optname, optval, optlen);
- else if (unlikely(!ops->getsockopt))
- err = -EOPNOTSUPP;
- else
- err = ops->getsockopt(sock, level, optname, optval,
- optlen);
-
- if (!in_compat_syscall())
- err = BPF_CGROUP_RUN_PROG_GETSOCKOPT(sock->sk, level, optname,
- USER_SOCKPTR(optval),
- USER_SOCKPTR(optlen),
- max_optlen, err);
-out_put:
fput_light(sock->file, fput_needed);
return err;
}
--
2.34.1