crypto/tls: add verifiedChains expiration checking during resumption

When resuming a session, check that the verifiedChains contain at least
one chain that is still valid at the time of resumption. If not, trigger
a new handshake.

Updates #77113
Updates #77217
Updates CVE-2025-68121

Change-Id: I14f585c43da17802513cbdd5b10c552d7a38b34e
Reviewed-on: https://go-review.googlesource.com/c/go/+/739321
Reviewed-by: Coia Prant <coiaprant@gmail.com>
Reviewed-by: Filippo Valsorda <filippo@golang.org>
Auto-Submit: Roland Shoemaker <roland@golang.org>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>

handshake_client.go

@@ -399,9 +399,6 @@ func (c *Conn) loadSession(hello *clientHelloMsg) (
 		return nil, nil, nil, nil
 	}
 
-	// Check that the cached server certificate is not expired, and that it's
-	// valid for the ServerName. This should be ensured by the cache key, but
-	// protect the application from a faulty ClientSessionCache implementation.
 	if c.config.time().After(session.peerCertificates[0].NotAfter) {
 		// Expired certificate, delete the entry.
 		c.config.ClientSessionCache.Put(cacheKey, nil)
@@ -413,6 +410,13 @@ func (c *Conn) loadSession(hello *clientHelloMsg) (
 			return nil, nil, nil, nil
 		}
 		if err := session.peerCertificates[0].VerifyHostname(c.config.ServerName); err != nil {
+			// This should be ensured by the cache key, but protect the
+			// application from a faulty ClientSessionCache implementation.
+			return nil, nil, nil, nil
+		}
+		if !anyUnexpiredChain(session.verifiedChains, c.config.time()) {
+			// No valid chains, delete the entry.
+			c.config.ClientSessionCache.Put(cacheKey, nil)
 			return nil, nil, nil, nil
 		}
 	}