From patchwork Wed Aug 9 12:58:51 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sabrina Dubroca X-Patchwork-Id: 13347952 X-Patchwork-Delegate: kuba@kernel.org Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E5F4818B09 for ; Wed, 9 Aug 2023 12:59:44 +0000 (UTC) Received: from us-smtp-delivery-44.mimecast.com (unknown [207.211.30.44]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 01F241FF9 for ; Wed, 9 Aug 2023 05:59:43 -0700 (PDT) Received: from mimecast-mx02.redhat.com (66.187.233.73 [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-21-UjERp_4sMz6znNLlqYM6Rw-1; Wed, 09 Aug 2023 08:59:25 -0400 X-MC-Unique: UjERp_4sMz6znNLlqYM6Rw-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id EC8AC3C11A02; Wed, 9 Aug 2023 12:59:24 +0000 (UTC) Received: from hog.localdomain (unknown [10.45.224.100]) by smtp.corp.redhat.com (Postfix) with ESMTP id 1B7032166B25; Wed, 9 Aug 2023 12:59:22 +0000 (UTC) From: Sabrina Dubroca To: netdev@vger.kernel.org Cc: Sabrina Dubroca , Vadim Fedorenko , Frantisek Krenzelok , Jakub Kicinski , Kuniyuki Iwashima , Apoorv Kothari , Boris Pismenny , John Fastabend , Shuah Khan , linux-kselftest@vger.kernel.org, Gal Pressman , Marcel Holtmann Subject: [PATCH net-next v3 2/6] tls: block decryption when a rekey is pending Date: Wed, 9 Aug 2023 14:58:51 +0200 Message-Id: In-Reply-To: References: Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.6 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: queasysnail.net X-Spam-Status: No, score=0.2 required=5.0 tests=BAYES_00,RCVD_IN_DNSWL_BLOCKED, RCVD_IN_VALIDITY_RPBL,RDNS_NONE,SPF_HELO_NONE,SPF_NONE autolearn=no autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net X-Patchwork-Delegate: kuba@kernel.org When a TLS handshake record carrying a KeyUpdate message is received, all subsequent records will be encrypted with a new key. We need to stop decrypting incoming records with the old key, and wait until userspace provides a new key. Make a note of this in the RX context just after decrypting that record, and stop recvmsg/splice calls with EKEYEXPIRED until the new key is available. v3: - move key_update_pending check into tls_rx_rec_wait (Jakub) - TLS_RECORD_TYPE_HANDSHAKE was added to include/net/tls_prot.h by the tls handshake series, drop that from this patch - move key_update_pending into an existing hole Signed-off-by: Sabrina Dubroca --- include/net/tls.h | 3 +++ net/tls/tls_sw.c | 36 ++++++++++++++++++++++++++++++++++++ 2 files changed, 39 insertions(+) diff --git a/include/net/tls.h b/include/net/tls.h index 06fca9160346..219a4f38c0e4 100644 --- a/include/net/tls.h +++ b/include/net/tls.h @@ -69,6 +69,8 @@ extern const struct tls_cipher_size_desc tls_cipher_size_desc[]; #define TLS_CRYPTO_INFO_READY(info) ((info)->cipher_type) +#define TLS_HANDSHAKE_KEYUPDATE 24 /* rfc8446 B.3: Key update */ + #define TLS_AAD_SPACE_SIZE 13 #define MAX_IV_SIZE 16 @@ -141,6 +143,7 @@ struct tls_sw_context_rx { u8 async_capable:1; u8 zc_capable:1; u8 reader_contended:1; + bool key_update_pending; struct tls_strparser strp; diff --git a/net/tls/tls_sw.c b/net/tls/tls_sw.c index 2ca0eb90a2a5..497f56c5f169 100644 --- a/net/tls/tls_sw.c +++ b/net/tls/tls_sw.c @@ -1293,6 +1293,10 @@ tls_rx_rec_wait(struct sock *sk, struct sk_psock *psock, bool nonblock, DEFINE_WAIT_FUNC(wait, woken_wake_function); long timeo; + /* a rekey is pending, let userspace deal with it */ + if (unlikely(ctx->key_update_pending)) + return -EKEYEXPIRED; + timeo = sock_rcvtimeo(sk, nonblock); while (!tls_strp_msg_ready(ctx)) { @@ -1689,6 +1693,33 @@ tls_decrypt_device(struct sock *sk, struct msghdr *msg, return 1; } +static int tls_check_pending_rekey(struct sock *sk, struct sk_buff *skb) +{ + const struct tls_msg *tlm = tls_msg(skb); + const struct strp_msg *rxm = strp_msg(skb); + + if (tlm->control == TLS_RECORD_TYPE_HANDSHAKE) { + char hs_type; + int err; + + if (rxm->full_len < 1) + return -EINVAL; + + err = skb_copy_bits(skb, rxm->offset, &hs_type, 1); + if (err < 0) + return err; + + if (hs_type == TLS_HANDSHAKE_KEYUPDATE) { + struct tls_context *ctx = tls_get_ctx(sk); + struct tls_sw_context_rx *rx_ctx = ctx->priv_ctx_rx; + + rx_ctx->key_update_pending = true; + } + } + + return 0; +} + static int tls_rx_one_record(struct sock *sk, struct msghdr *msg, struct tls_decrypt_arg *darg) { @@ -1708,6 +1739,10 @@ static int tls_rx_one_record(struct sock *sk, struct msghdr *msg, rxm->full_len -= prot->overhead_size; tls_advance_record_sn(sk, prot, &tls_ctx->rx); + err = tls_check_pending_rekey(sk, darg->skb); + if (err < 0) + return err; + return 0; } @@ -2642,6 +2677,7 @@ int tls_set_sw_offload(struct sock *sk, int tx) skb_queue_head_init(&sw_ctx_rx->rx_list); skb_queue_head_init(&sw_ctx_rx->async_hold); aead = &sw_ctx_rx->aead_recv; + sw_ctx_rx->key_update_pending = false; } switch (crypto_info->cipher_type) {