On 07/24, Breno Leitao wrote:
> Add support for getsockopt command (SOCKET_URING_OP_GETSOCKOPT), where
> level is SOL_SOCKET. This is leveraging the sockptr_t infrastructure,
> where a sockptr_t is either userspace or kernel space, and handled as
> such.
>
> Function io_uring_cmd_getsockopt() is inspired by __sys_getsockopt().
We probably need to also have bpf bits in the new
io_uring_cmd_getsockopt?
> Differently from the getsockopt(2), the optlen field is not a userspace
> pointers. In getsockopt(2), userspace provides optlen pointer, which is
> overwritten by the kernel. In this implementation, userspace passes a
> u32, and the new value is returned in cqe->res. I.e., optlen is not a
> pointer.
>
> Important to say that userspace needs to keep the pointer alive until
> the CQE is completed.
>
> Signed-off-by: Breno Leitao <leitao@xxxxxxxxxx>
> ---
> include/uapi/linux/io_uring.h | 7 ++++++
> io_uring/uring_cmd.c | 43 +++++++++++++++++++++++++++++++++++
> 2 files changed, 50 insertions(+)
>
> diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h
> index 9fc7195f25df..8152151080db 100644
> --- a/include/uapi/linux/io_uring.h
> +++ b/include/uapi/linux/io_uring.h
> @@ -43,6 +43,10 @@ struct io_uring_sqe {
> union {
> __u64 addr; /* pointer to buffer or iovecs */
> __u64 splice_off_in;
> + struct {
> + __u32 level;
> + __u32 optname;
> + };
> };
> __u32 len; /* buffer size or number of iovecs */
> union {
> @@ -79,6 +83,7 @@ struct io_uring_sqe {
> union {
> __s32 splice_fd_in;
> __u32 file_index;
> + __u32 optlen;
> struct {
> __u16 addr_len;
> __u16 __pad3[1];
> @@ -89,6 +94,7 @@ struct io_uring_sqe {
> __u64 addr3;
> __u64 __pad2[1];
> };
> + __u64 optval;
> /*
> * If the ring is initialized with IORING_SETUP_SQE128, then
> * this field is used for 80 bytes of arbitrary command data
> @@ -729,6 +735,7 @@ struct io_uring_recvmsg_out {
> enum {
> SOCKET_URING_OP_SIOCINQ = 0,
> SOCKET_URING_OP_SIOCOUTQ,
> + SOCKET_URING_OP_GETSOCKOPT,
> };
>
> #ifdef __cplusplus
> diff --git a/io_uring/uring_cmd.c b/io_uring/uring_cmd.c
> index 8e7a03c1b20e..16c857cbf3b0 100644
> --- a/io_uring/uring_cmd.c
> +++ b/io_uring/uring_cmd.c
> @@ -166,6 +166,47 @@ int io_uring_cmd_import_fixed(u64 ubuf, unsigned long len, int rw,
> }
> EXPORT_SYMBOL_GPL(io_uring_cmd_import_fixed);
>
> +static inline int io_uring_cmd_getsockopt(struct socket *sock,
> + struct io_uring_cmd *cmd)
> +{
> + void __user *optval = u64_to_user_ptr(READ_ONCE(cmd->sqe->optval));
> + int optname = READ_ONCE(cmd->sqe->optname);
> + int optlen = READ_ONCE(cmd->sqe->optlen);
> + int level = READ_ONCE(cmd->sqe->level);
> + void *koptval;
> + int err;
> +
> + err = security_socket_getsockopt(sock, level, optname);
> + if (err)
> + return err;
> +
> + koptval = kmalloc(optlen, GFP_KERNEL);
> + if (!koptval)
> + return -ENOMEM;
> +
> + err = copy_from_user(koptval, optval, optlen);
> + if (err)
> + goto fail;
> +
> + err = -EOPNOTSUPP;
> + if (level == SOL_SOCKET) {
> + err = sk_getsockopt(sock->sk, level, optname,
> + KERNEL_SOCKPTR(koptval),
> + KERNEL_SOCKPTR(&optlen));
> + if (err)
> + goto fail;
> + }
> +
> + err = copy_to_user(optval, koptval, optlen);
> +
> +fail:
> + kfree(koptval);
> + if (err)
> + return err;
> + else
> + return optlen;
> +}
> +
> int io_uring_cmd_sock(struct io_uring_cmd *cmd, unsigned int issue_flags)
> {
> struct socket *sock = cmd->file->private_data;
> @@ -187,6 +228,8 @@ int io_uring_cmd_sock(struct io_uring_cmd *cmd, unsigned int issue_flags)
> if (ret)
> return ret;
> return arg;
> + case SOCKET_URING_OP_GETSOCKOPT:
> + return io_uring_cmd_getsockopt(sock, cmd);
> default:
> return -EOPNOTSUPP;
> }
> --
> 2.34.1
>
