v3: added following Jakub's comment Signed-off-by: Sabrina Dubroca <sd@xxxxxxxxxxxxxxx> --- Documentation/networking/tls.rst | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) diff --git a/Documentation/networking/tls.rst b/Documentation/networking/tls.rst index 658ed3a71e1b..ea6a22eafe2b 100644 --- a/Documentation/networking/tls.rst +++ b/Documentation/networking/tls.rst @@ -200,6 +200,27 @@ received without a cmsg buffer set. recv will never return data from mixed types of TLS records. +TLS 1.3 Key Updates +------------------- + +In TLS 1.3, KeyUpdate handshake messages signal that the sender is +updating its TX key. Any message sent after a KeyUpdate will be +encrypted using the new key. The userspace library can pass the new +key to the kernel using the TLS_TX and TLS_RX socket options, as for +the initial keys. TLS version and cipher cannot be changed. + +To prevent attempting to decrypt incoming records using the wrong key, +decryption will be paused when a KeyUpdate message is received by the +kernel, until the new key has been provided using the TLS_RX socket +option. Any read occurring after the KeyUpdate has been read and +before the new key is provided will fail with EKEYEXPIRED. Poll()'ing +the socket will also sleep until the new key is provided. There is no +pausing on the transmit side. + +Userspace should make sure that the crypto_info provided has been set +properly. In particular, the kernel will not check for key/nonce +reuse. + Integrating in to userspace TLS library --------------------------------------- -- 2.40.1
