Re: [PATCH 07/18] net/tls: sanitize MSG_EOR handling

Sagi Grimberg
2023-04-17T15:19:15Z

> The TLS stack is using MSG_EOR internally, so the flag cannot be
> set for sendmsg()/sendpage(). But to avoid having the caller to
> check whether TLS is active modify the code to clear the MSG_EOR
> flag. And blank out MSG_MORE / MSG_SENDPAGE_NOTLAST, too, as they
> conflict with MSG_EOR anyway.

This looks like a temporary workaround to me.

The networking folks really need to be CC'd on this (same for patch 6).

CC'ing Jakub for starters.

> Signed-off-by: Hannes Reinecke <hare@suse.de>
> ---
> net/tls/tls_device.c | 10 ++++++++++
> net/tls/tls_sw.c | 21 +++++++++++++++++++++
> 2 files changed, 31 insertions(+)
>
> diff --git a/net/tls/tls_device.c b/net/tls/tls_device.c
> index a7cc4f9faac2..38e44e216865 100644
> --- a/net/tls/tls_device.c
> +++ b/net/tls/tls_device.c
> @@ -576,6 +576,10 @@ int tls_device_sendmsg(struct sock *sk, struct msghdr *msg, size_t size)
> mutex_lock(&tls_ctx->tx_lock);
> lock_sock(sk);
>
> + /* MSG_EOR conflicts with MSG_MORE, so clear both */
> + if (msg->msg_flags & MSG_EOR)
> + msg->msg_flags &= ~(MSG_EOR | MSG_MORE);
> +
> if (unlikely(msg->msg_controllen)) {
> rc = tls_process_cmsg(sk, msg, &record_type);
> if (rc)
> @@ -604,6 +608,12 @@ int tls_device_sendpage(struct sock *sk, struct page *page,
> if (flags & MSG_SENDPAGE_NOTLAST)
> flags |= MSG_MORE;
>
> + /*
> + * MSG_EOR conflicts with MSG_MORE/MSG_SENDPAGE_NOTLAST,
> + * so clear all of them */
> + if (flags & MSG_EOR)
> + flags &= ~(MSG_EOR | MSG_SENDPAGE_NOTLAST | MSG_MORE);
> +
> mutex_lock(&tls_ctx->tx_lock);
> lock_sock(sk);
>
> diff --git a/net/tls/tls_sw.c b/net/tls/tls_sw.c
> index 827292e29f99..d0e6b7a04176 100644
> --- a/net/tls/tls_sw.c
> +++ b/net/tls/tls_sw.c
> @@ -952,6 +952,11 @@ int tls_sw_sendmsg(struct sock *sk, struct msghdr *msg, size_t size)
> int ret = 0;
> int pending;
>
> + if (msg->msg_flags & MSG_EOR) {
> + eor = true;
> + /* MSG_EOR conflicts with MSG_MORE, so clear both */
> + msg->msg_flags &= ~(MSG_EOR | MSG_MORE);
> + }
> if (msg->msg_flags & ~(MSG_MORE | MSG_DONTWAIT | MSG_NOSIGNAL |
> MSG_CMSG_COMPAT))
> return -EOPNOTSUPP;
> @@ -1274,6 +1279,14 @@ static int tls_sw_do_sendpage(struct sock *sk, struct page *page,
> int tls_sw_sendpage_locked(struct sock *sk, struct page *page,
> int offset, size_t size, int flags)
> {
> + /*
> + * MSG_EOR is invalid for TLS, and conflicts
> + * with MSG_MORE / MSG_SENDPAGE_NOTLAST.
> + * So clear all of them.
> + */
> + if (flags & MSG_EOR)
> + flags &= ~(MSG_MORE | MSG_SENDPAGE_NOTLAST | MSG_EOR);
> +
> if (flags & ~(MSG_MORE | MSG_DONTWAIT | MSG_NOSIGNAL |
> MSG_SENDPAGE_NOTLAST | MSG_SENDPAGE_NOPOLICY |
> MSG_NO_SHARED_FRAGS))
> @@ -1288,6 +1301,14 @@ int tls_sw_sendpage(struct sock *sk, struct page *page,
> struct tls_context *tls_ctx = tls_get_ctx(sk);
> int ret;
>
> + /*
> + * MSG_EOR is invalid for TLS, and conflicts
> + * with MSG_MORE / MSG_SENDPAGE_NOTLAST.
> + * So clear all of them.
> + */
> + if (flags & MSG_EOR)
> + flags &= ~(MSG_MORE | MSG_SENDPAGE_NOTLAST | MSG_EOR);
> +
> if (flags & ~(MSG_MORE | MSG_DONTWAIT | MSG_NOSIGNAL |
> MSG_SENDPAGE_NOTLAST | MSG_SENDPAGE_NOPOLICY))
> return -EOPNOTSUPP;