From 4c4c22639eb2794e563370a2ee48a34dbdddc639 Mon Sep 17 00:00:00 2001 From: Isaac Boukris Date: Sat, 6 Jun 2020 11:03:37 +0200 Subject: [PATCH] Omit PA_FOR_USER if we can't compute its checksum OpenSSL in FIPS mode will refuse to perform hmac-md5. Omit the legacy PA_FOR_USER element in this case rather than failing out. [ghudson@mit.edu: minor code and comment edits; wrote commit message] ticket: 8912 (new) (cherry picked from commit 03f122bdb22cfa53c7d855ed929c9541e56365e0) (cherry picked from commit 086de78292b8ae89aba8a72926831124da44205d) --- src/lib/krb5/krb/s4u_creds.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/src/lib/krb5/krb/s4u_creds.c b/src/lib/krb5/krb/s4u_creds.c index fc5c886d6..d8f486dc6 100644 --- a/src/lib/krb5/krb/s4u_creds.c +++ b/src/lib/krb5/krb/s4u_creds.c @@ -534,6 +534,13 @@ krb5_get_self_cred_from_kdc(krb5_context context, if (s4u_user.user_id.user != NULL && s4u_user.user_id.user->length) { code = build_pa_for_user(context, tgtptr, &s4u_user.user_id, &in_padata[1]); + /* + * If we couldn't compute the hmac-md5 checksum, send only the + * KRB5_PADATA_S4U_X509_USER; this will still work against modern + * Windows and MIT KDCs. + */ + if (code == KRB5_CRYPTO_INTERNAL) + code = 0; if (code != 0) { krb5_free_pa_data(context, in_padata); goto cleanup;