From f4571b64d552d445072ecbcfdbb289e0377db65a Mon Sep 17 00:00:00 2001 From: yuhan6665 <1588741+yuhan6665@users.noreply.github.com> Date: Sun, 10 May 2026 22:19:06 -0400 Subject: [PATCH] crypto/tls: prevent deadlock when client sends multiple key update messages When we made setReadTrafficSecret send an alert when there are pending handshake messages, we introduced a deadlock when the client sends multiple key update messages that request a response, as handleKeyUpdate will lock the mutex, and defer the unlocking until the end of the function, but setReadTrafficSecret called sendAlert in the failure case, which also tries to lock the mutex. Add an argument to setReadTrafficSecret which lets the caller indicate if the mutex is already locked, and if so, call sendAlertLocked instead of sendAlert. Thanks to Jakub Ciolek for reporting this issue. Fixes #78334 Fixes CVE-2026-32283 Change-Id: Id8e56974233c910e0d66ba96eafbd2ea57832610 Reviewed-on: https://go-internal-review.googlesource.com/c/go/+/3881 Reviewed-by: Damien Neil Reviewed-by: Nicholas Husin Reviewed-on: https://go-review.googlesource.com/c/go/+/763767 LUCI-TryBot-Result: Go LUCI Auto-Submit: David Chase Reviewed-by: Russ Cox Reviewed-by: Jakub Ciolek --- conn.go | 10 +++++++--- handshake_client_tls13.go | 4 ++-- handshake_server_tls13.go | 4 ++-- 3 files changed, 11 insertions(+), 7 deletions(-) diff --git a/conn.go b/conn.go index e2b3d3d..b239dab 100644 --- a/conn.go +++ b/conn.go @@ -1429,7 +1429,7 @@ func (c *Conn) handleKeyUpdate(keyUpdate *keyUpdateMsg) error { } newSecret := cipherSuite.nextTrafficSecret(c.in.trafficSecret) - if err := c.setReadTrafficSecret(cipherSuite, QUICEncryptionLevelInitial, newSecret); err != nil { + if err := c.setReadTrafficSecret(cipherSuite, QUICEncryptionLevelInitial, newSecret, keyUpdate.updateRequested); err != nil { return err } @@ -1747,12 +1747,16 @@ func (c *Conn) VerifyHostname(host string) error { // setReadTrafficSecret sets the read traffic secret for the given encryption level. If // being called at the same time as setWriteTrafficSecret, the caller must ensure the call // to setWriteTrafficSecret happens first so any alerts are sent at the write level. -func (c *Conn) setReadTrafficSecret(suite *cipherSuiteTLS13, level QUICEncryptionLevel, secret []byte) error { +func (c *Conn) setReadTrafficSecret(suite *cipherSuiteTLS13, level QUICEncryptionLevel, secret []byte, locked bool) error { // Ensure that there are no buffered handshake messages before changing the // read keys, since that can cause messages to be parsed that were encrypted // using old keys which are no longer appropriate. if c.hand.Len() != 0 { - c.sendAlert(alertUnexpectedMessage) + if locked { + c.sendAlertLocked(alertUnexpectedMessage) + } else { + c.sendAlert(alertUnexpectedMessage) + } return errors.New("tls: handshake buffer not empty before setting read traffic secret") } c.in.setTrafficSecret(suite, level, secret) diff --git a/handshake_client_tls13.go b/handshake_client_tls13.go index bb37e86..b30f992 100644 --- a/handshake_client_tls13.go +++ b/handshake_client_tls13.go @@ -492,7 +492,7 @@ func (hs *clientHandshakeStateTLS13) establishHandshakeKeys() error { clientSecret := handshakeSecret.ClientHandshakeTrafficSecret(hs.transcript) c.setWriteTrafficSecret(hs.suite, QUICEncryptionLevelHandshake, clientSecret) serverSecret := handshakeSecret.ServerHandshakeTrafficSecret(hs.transcript) - if err := c.setReadTrafficSecret(hs.suite, QUICEncryptionLevelHandshake, serverSecret); err != nil { + if err := c.setReadTrafficSecret(hs.suite, QUICEncryptionLevelHandshake, serverSecret, false); err != nil { return err } @@ -711,7 +711,7 @@ func (hs *clientHandshakeStateTLS13) readServerFinished() error { hs.trafficSecret = hs.masterSecret.ClientApplicationTrafficSecret(hs.transcript) serverSecret := hs.masterSecret.ServerApplicationTrafficSecret(hs.transcript) - if err := c.setReadTrafficSecret(hs.suite, QUICEncryptionLevelApplication, serverSecret); err != nil { + if err := c.setReadTrafficSecret(hs.suite, QUICEncryptionLevelApplication, serverSecret, false); err != nil { return err } diff --git a/handshake_server_tls13.go b/handshake_server_tls13.go index 4d049aa..0e1a0c5 100644 --- a/handshake_server_tls13.go +++ b/handshake_server_tls13.go @@ -854,7 +854,7 @@ func (hs *serverHandshakeStateTLS13) sendServerParameters() error { serverSecret := hs.handshakeSecret.ServerHandshakeTrafficSecret(hs.transcript) c.setWriteTrafficSecret(hs.suite, QUICEncryptionLevelHandshake, serverSecret) clientSecret := hs.handshakeSecret.ClientHandshakeTrafficSecret(hs.transcript) - if err := c.setReadTrafficSecret(hs.suite, QUICEncryptionLevelHandshake, clientSecret); err != nil { + if err := c.setReadTrafficSecret(hs.suite, QUICEncryptionLevelHandshake, clientSecret, false); err != nil { return err } @@ -1238,7 +1238,7 @@ func (hs *serverHandshakeStateTLS13) readClientFinished() error { return errors.New("tls: invalid client finished hash") } - if err := c.setReadTrafficSecret(hs.suite, QUICEncryptionLevelApplication, hs.trafficSecret); err != nil { + if err := c.setReadTrafficSecret(hs.suite, QUICEncryptionLevelApplication, hs.trafficSecret, false); err != nil { return err }