[RFC PATCH 3/3] io_uring/cmd: Add support for set_sockopt

[Breno Leitao]

Add initial support for setsockopt for SOL_SOCKET level, by leveraging
the sockptr infrastructure.

Function io_uring_cmd_setsockopt is inspired by the function
__sys_setsockopt(), which handles the system call case.

Signed-off-by: Breno Leitao <leitao@xxxxxxxxxx>
---
 include/uapi/linux/io_uring.h |  1 +
 io_uring/uring_cmd.c          | 24 ++++++++++++++++++++++++
 2 files changed, 25 insertions(+)

diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h
index 8152151080db..3fe82df06abf 100644
--- a/include/uapi/linux/io_uring.h
+++ b/include/uapi/linux/io_uring.h
@@ -736,6 +736,7 @@ enum {
 	SOCKET_URING_OP_SIOCINQ		= 0,
 	SOCKET_URING_OP_SIOCOUTQ,
 	SOCKET_URING_OP_GETSOCKOPT,
+	SOCKET_URING_OP_SETSOCKOPT,
 };
 
 #ifdef __cplusplus
diff --git a/io_uring/uring_cmd.c b/io_uring/uring_cmd.c
index 28fd09351be7..7c06634e744a 100644
--- a/io_uring/uring_cmd.c
+++ b/io_uring/uring_cmd.c
@@ -191,6 +191,28 @@ static inline int io_uring_cmd_getsockopt(struct socket *sock,
 	return -EOPNOTSUPP;
 }
 
+static inline int io_uring_cmd_setsockopt(struct socket *sock,
+					  struct io_uring_cmd *cmd)
+{
+	void __user *optval = u64_to_user_ptr(READ_ONCE(cmd->sqe->optval));
+	int optlen = READ_ONCE(cmd->sqe->optlen);
+	int optname = READ_ONCE(cmd->sqe->optname);
+	int level = READ_ONCE(cmd->sqe->level);
+	int err;
+
+	err = security_socket_setsockopt(sock, level, optname);
+	if (err)
+		return err;
+
+	if (level == SOL_SOCKET && !sock_use_custom_sol_socket(sock)) {
+		err = sock_setsockopt(sock, level, optname,
+				      USER_SOCKPTR(optval), optlen);
+		return err;
+	}
+
+	return -EOPNOTSUPP;
+}
+
 int io_uring_cmd_sock(struct io_uring_cmd *cmd, unsigned int issue_flags)
 {
 	struct socket *sock = cmd->file->private_data;
@@ -214,6 +236,8 @@ int io_uring_cmd_sock(struct io_uring_cmd *cmd, unsigned int issue_flags)
 		return arg;
 	case SOCKET_URING_OP_GETSOCKOPT:
 		return io_uring_cmd_getsockopt(sock, cmd);
+	case SOCKET_URING_OP_SETSOCKOPT:
+		return io_uring_cmd_setsockopt(sock, cmd);
 	default:
 		return -EOPNOTSUPP;
 	}
-- 
2.34.1