Blame SOURCES/Omit-PA_FOR_USER-if-we-can-t-compute-its-checksum.patch

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From e1b2c967266b14bc37e5ed11e6c0525bd259e0bb Mon Sep 17 00:00:00 2001
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From: Isaac Boukris <iboukris@gmail.com>
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Date: Sat, 6 Jun 2020 11:03:37 +0200
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Subject: [PATCH] Omit PA_FOR_USER if we can't compute its checksum
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OpenSSL in FIPS mode will refuse to perform hmac-md5.  Omit the legacy
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PA_FOR_USER element in this case rather than failing out.
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[ghudson@mit.edu: minor code and comment edits; wrote commit message]
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ticket: 8912 (new)
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(cherry picked from commit 03f122bdb22cfa53c7d855ed929c9541e56365e0)
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(cherry picked from commit 086de78292b8ae89aba8a72926831124da44205d)
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---
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 src/lib/krb5/krb/s4u_creds.c | 7 +++++++
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 1 file changed, 7 insertions(+)
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diff --git a/src/lib/krb5/krb/s4u_creds.c b/src/lib/krb5/krb/s4u_creds.c
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index fc5c886d6..d8f486dc6 100644
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--- a/src/lib/krb5/krb/s4u_creds.c
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+++ b/src/lib/krb5/krb/s4u_creds.c
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@@ -534,6 +534,13 @@ krb5_get_self_cred_from_kdc(krb5_context context,
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         if (s4u_user.user_id.user != NULL && s4u_user.user_id.user->length) {
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             code = build_pa_for_user(context, tgtptr, &s4u_user.user_id,
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                                      &in_padata[1]);
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+            /*
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+             * If we couldn't compute the hmac-md5 checksum, send only the
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+             * KRB5_PADATA_S4U_X509_USER; this will still work against modern
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+             * Windows and MIT KDCs.
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+             */
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+            if (code == KRB5_CRYPTO_INTERNAL)
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+                code = 0;
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             if (code != 0) {
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                 krb5_free_pa_data(context, in_padata);
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                 goto cleanup;