2025-09-23, 15:32:06 +1000, Wilfred Mallawa wrote:
> diff --git a/net/tls/tls_main.c b/net/tls/tls_main.c
> index a3ccb3135e51..09883d9c6c96 100644
> --- a/net/tls/tls_main.c
> +++ b/net/tls/tls_main.c
> @@ -544,6 +544,31 @@ static int do_tls_getsockopt_no_pad(struct sock *sk,
> char __user *optval,
> return 0;
> }
>
> +static int do_tls_getsockopt_tx_record_size(struct sock *sk, char __user
> *optval,
> + int __user *optlen)
> +{
> + struct tls_context *ctx = tls_get_ctx(sk);
> + int len;
> + /* TLS 1.3: Record length contains ContentType */
> + u16 record_size_limit = ctx->prot_info.version == TLS_1_3_VERSION ?
> + ctx->tx_record_size_limit + 1 :
> + ctx->tx_record_size_limit;
nit: reverse xmas tree
[...]
> +static int do_tls_setsockopt_tx_record_size(struct sock *sk, sockptr_t
> optval,
> + unsigned int optlen)
> +{
> + struct tls_context *ctx = tls_get_ctx(sk);
> + struct tls_sw_context_tx *sw_ctx = tls_sw_ctx_tx(ctx);
> + u16 value;
> +
> + if (sw_ctx->open_rec)
> + return -EBUSY;
> +
> + if (sockptr_is_null(optval) || optlen != sizeof(value))
> + return -EINVAL;
> +
> + if (copy_from_sockptr(&value, optval, sizeof(value)))
> + return -EFAULT;
> +
> + if (value < TLS_MIN_RECORD_SIZE_LIM)
> + return -EINVAL;
> +
> + if (ctx->prot_info.version == TLS_1_2_VERSION &&
> + value > TLS_MAX_PAYLOAD_SIZE)
> + return -EINVAL;
> +
> + if (ctx->prot_info.version == TLS_1_3_VERSION &&
> + value - 1 > TLS_MAX_PAYLOAD_SIZE)
> + return -EINVAL;
> +
> + /*
> + * For TLS 1.3: 'value' includes one byte for the appended ContentType.
> + * Adjust the kernel's internal plaintext limit accordingly.
> + */
> + ctx->tx_record_size_limit = ctx->prot_info.version == TLS_1_3_VERSION ?
> + value - 1 : value;
> +
> + return 0;
> +}
> +
> static int do_tls_setsockopt(struct sock *sk, int optname, sockptr_t optval,
> unsigned int optlen)
> {
> @@ -833,6 +898,9 @@ static int do_tls_setsockopt(struct sock *sk, int
> optname, sockptr_t optval,
> case TLS_RX_EXPECT_NO_PAD:
> rc = do_tls_setsockopt_no_pad(sk, optval, optlen);
> break;
> + case TLS_TX_RECORD_SIZE_LIM:
> + rc = do_tls_setsockopt_tx_record_size(sk, optval, optlen);
I think we want to lock the socket here, to avoid any concurrent send()?
Especially now with the ->open_rec check.
> @@ -1111,6 +1180,11 @@ static int tls_get_info(struct sock *sk, struct
> sk_buff *skb, bool net_admin)
> goto nla_failure;
> }
>
> + err = nla_put_u16(skb, TLS_INFO_TX_RECORD_SIZE_LIM,
> + ctx->tx_record_size_limit);
I'm not sure here: if we do the +1 adjustment we'd be consistent with
the value reported by getsockopt, but OTOH users may get confused
about seeing a value larger than TLS_MAX_PAYLOAD_SIZE.
--
Sabrina
