98 lines
4.2 KiB
Diff
98 lines
4.2 KiB
Diff
From 8f70ad82a645ccb7fb1677d260baa5e4112890d4 Mon Sep 17 00:00:00 2001
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From: Greg Hudson <ghudson@mit.edu>
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Date: Mon, 7 Jun 2021 13:27:29 -0400
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Subject: [PATCH] Fix some principal realm canonicalization cases
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The no_hostrealm and subst_defrealm flags in struct canonprinc were
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only applied when dns_canonicalize_hostname=fallback; in the other
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cases, the initial krb5_sname_to_principal() result is treated as
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canonical. For no_hostrealm this limitation doesn't currently matter,
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because all uses pass a principal with no realm as input. However,
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subst_defrealm is used to convert the referral realm to the default
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realm in krb5_get_init_creds_keytab(), krb5_cc_cache_match(), and
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gss_acquire_cred() when it needs to check the desired name against a
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specified ccache.
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In k5_canonprinc(), if the input principal is a
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krb5_sname_to_principal() result and fallback isn't in effect, apply
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subst_defrealm. Document in os-proto.h that no_hostrealm doesn't
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remove an existing realm and that krb5_sname_to_principal() may
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already have looked one up.
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ticket: 9011 (new)
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(cherry picked from commit c077d0c6430c4ac163443aacc03d14d206a4cbb8)
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(cherry picked from commit 5ae9bc98f23aeaa2ce17debe5a9b0cf1130e54ed)
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---
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src/lib/krb5/os/os-proto.h | 13 +++++++++----
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src/lib/krb5/os/sn2princ.c | 24 +++++++++++++++++++++---
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2 files changed, 30 insertions(+), 7 deletions(-)
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diff --git a/src/lib/krb5/os/os-proto.h b/src/lib/krb5/os/os-proto.h
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index 7d5e7978f..a985f2aec 100644
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--- a/src/lib/krb5/os/os-proto.h
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+++ b/src/lib/krb5/os/os-proto.h
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@@ -85,10 +85,15 @@ struct sendto_callback_info {
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/*
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* Initialize with all zeros except for princ. Set no_hostrealm to disable
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- * host-to-realm lookup, which ordinarily happens after canonicalizing the host
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- * part. Set subst_defrealm to substitute the default realm for the referral
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- * realm after realm lookup (this has no effect if no_hostrealm is set). Free
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- * with free_canonprinc() when done.
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+ * host-to-realm lookup, which ordinarily happens during fallback processing
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+ * after canonicalizing the host part. Set subst_defrealm to substitute the
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+ * default realm for the referral realm after realm lookup. Do not set both
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+ * flags. Free with free_canonprinc() when done.
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+ *
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+ * no_hostrealm only applies if fallback processing is in use
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+ * (dns_canonicalize_hostname = fallback). It will not remove the realm if
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+ * krb5_sname_to_principal() already canonicalized the hostname and looked up a
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+ * realm. subst_defrealm applies whether or not fallback processing is in use.
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*/
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struct canonprinc {
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krb5_const_principal princ;
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diff --git a/src/lib/krb5/os/sn2princ.c b/src/lib/krb5/os/sn2princ.c
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index c99b7da17..93c155932 100644
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--- a/src/lib/krb5/os/sn2princ.c
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+++ b/src/lib/krb5/os/sn2princ.c
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@@ -271,18 +271,36 @@ krb5_error_code
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k5_canonprinc(krb5_context context, struct canonprinc *iter,
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krb5_const_principal *princ_out)
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{
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+ krb5_error_code ret;
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int step = ++iter->step;
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*princ_out = NULL;
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- /* If we're not doing fallback, the input principal is canonical. */
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- if (context->dns_canonicalize_hostname != CANONHOST_FALLBACK ||
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- iter->princ->type != KRB5_NT_SRV_HST || iter->princ->length != 2 ||
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+ /* If the hostname isn't from krb5_sname_to_principal(), the input
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+ * principal is canonical. */
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+ if (iter->princ->type != KRB5_NT_SRV_HST || iter->princ->length != 2 ||
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iter->princ->data[1].length == 0) {
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*princ_out = (step == 1) ? iter->princ : NULL;
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return 0;
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}
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+ /* If we're not doing fallback, the hostname is canonical, but we may need
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+ * to substitute the default realm. */
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+ if (context->dns_canonicalize_hostname != CANONHOST_FALLBACK) {
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+ if (step > 1)
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+ return 0;
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+ iter->copy = *iter->princ;
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+ if (iter->subst_defrealm && iter->copy.realm.length == 0) {
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+ ret = krb5_get_default_realm(context, &iter->realm);
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+ if (ret)
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+ return ret;
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+ iter->copy = *iter->princ;
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+ iter->copy.realm = string2data(iter->realm);
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+ }
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+ *princ_out = &iter->copy;
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+ return 0;
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+ }
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+
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/* Canonicalize without DNS at step 1, with DNS at step 2. */
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if (step > 2)
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return 0;
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