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[net-next,v3,4/6] docs: tls: document TLS1.3 key updates

Message ID 9916d6a35c659d639f6f52488ceea227a523ab63.1691584074.git.sd@queasysnail.net (mailing list archive)
State Changes Requested
Delegated to: Netdev Maintainers
Headers show
Series tls: implement key updates for TLS1.3 | expand

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Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for net-next
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 9 this patch: 9
netdev/cc_maintainers warning 3 maintainers not CCed: pabeni@redhat.com edumazet@google.com davem@davemloft.net
netdev/build_clang success Errors and warnings before: 9 this patch: 9
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 9 this patch: 9
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 27 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Sabrina Dubroca Aug. 9, 2023, 12:58 p.m. UTC 
v3: added following Jakub's comment

Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
---
 Documentation/networking/tls.rst | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)
diff mbox series

Patch

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
 ---------------------------------------