net/socket: Break down __sys_getsockopt

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>
Acked-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20231016134750.1381153-5-leitao@debian.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/include/linux/bpf-cgroup.h b/include/linux/bpf-cgroup.h
index cecfe8c..ffaca1a 100644 (file)
--- 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 24fbf71..cffb77a 100644 (file)
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -1869,11 +1869,11 @@ 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);
-int sock_getsockopt(struct socket *sock, int level, int op,
-                   char __user *optval, int __user *optlen);
 int sock_gettstamp(struct socket *sock, void __user *userstamp,
                   bool timeval, bool time32);
 struct sk_buff *sock_alloc_send_pskb(struct sock *sk, unsigned long header_len,

diff --git a/net/core/sock.c b/net/core/sock.c
index 16584e2..223eed5 100644 (file)
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -2010,14 +2010,6 @@ lenout:
        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 63be25d..eb69609 100644 (file)
--- a/net/socket.c
+++ b/net/socket.c
@@ -2333,6 +2333,43 @@ 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;
+
+       if (!compat)
+               max_optlen = BPF_CGROUP_GETSOCKOPT_MAX_OPTLEN(optlen);
+
+       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)
+               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.
@@ -2340,37 +2377,18 @@ 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;
        struct socket *sock;
+       bool compat;
 
        sock = sockfd_lookup_light(fd, &err, &fput_needed);
        if (!sock)
                return err;
 
-       err = security_socket_getsockopt(sock, level, optname);
-       if (err)
-               goto out_put;
+       compat = in_compat_syscall();
+       err = do_sock_getsockopt(sock, compat, level, optname,
+                                USER_SOCKPTR(optval), USER_SOCKPTR(optlen));
 
-       if (!in_compat_syscall())
-               max_optlen = BPF_CGROUP_GETSOCKOPT_MAX_OPTLEN(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;
 }