From f72a51059068a97c9a95e8b6cab522fdd549f8d3 Mon Sep 17 00:00:00 2001 From: Elena Uziunaite Date: Tue, 20 Aug 2024 12:11:57 +0100 Subject: [PATCH] Edit ChangeLog entry Signed-off-by: Elena Uziunaite --- ChangeLog.d/fix_reporting_of_key_usage_issues.txt | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) diff --git a/ChangeLog.d/fix_reporting_of_key_usage_issues.txt b/ChangeLog.d/fix_reporting_of_key_usage_issues.txt index 12f1bb3799..75fbb6cc15 100644 --- a/ChangeLog.d/fix_reporting_of_key_usage_issues.txt +++ b/ChangeLog.d/fix_reporting_of_key_usage_issues.txt @@ -1,4 +1,11 @@ -Bugfix - * Fix the failure to correctly update verification flags when - checking the (ext)KeyUsage extension. - Resolves #1260 +Security + * With TLS 1.3, when a server enables optional authentication of the + client, if the client-provided certificate does not have appropriate values + in if keyUsage or extKeyUsage extensions, then the return value of + mbedtls_ssl_get_verify_result() would incorrectly have the + MBEDTLS_X509_BADCERT_KEY_USAGE and MBEDTLS_X509_BADCERT_KEY_USAGE bits + clear. As a result, an attacker that had a certificate valid for uses other + than TLS client authentication could be able to use it for TLS client + authentication anyway. Only TLS 1.3 servers were affected, and only with + optional authentication (required would abort the handshake with a fatal + alert).