You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
49 lines
1.7 KiB
49 lines
1.7 KiB
From 137e424f7ae7c054e1dcb41c929a961bb021ed8b Mon Sep 17 00:00:00 2001
|
|
From: Andreas Schneider <asn@samba.org>
|
|
Date: Fri, 4 Aug 2023 09:54:06 +0200
|
|
Subject: [PATCH] Fix double-free in KDC TGS processing
|
|
|
|
When issuing a ticket for a TGS renew or validate request, copy only
|
|
the server field from the outer part of the header ticket to the new
|
|
ticket. Copying the whole structure causes the enc_part pointer to be
|
|
aliased to the header ticket until krb5_encrypt_tkt_part() is called,
|
|
resulting in a double-free if handle_authdata() fails.
|
|
|
|
[ghudson@mit.edu: changed the fix to avoid aliasing enc_part rather
|
|
than check for aliasing before freeing; rewrote commit message]
|
|
|
|
CVE-2023-39975:
|
|
|
|
In MIT krb5 release 1.21, an authenticated attacker can cause a KDC to
|
|
free the same pointer twice if it can induce a failure in
|
|
authorization data handling.
|
|
|
|
ticket: 9101 (new)
|
|
tags: pullup
|
|
target_version: 1.21-next
|
|
|
|
(cherry picked from commit 88a1701b423c13991a8064feeb26952d3641d840)
|
|
---
|
|
src/kdc/do_tgs_req.c | 5 +++--
|
|
1 file changed, 3 insertions(+), 2 deletions(-)
|
|
|
|
diff --git a/src/kdc/do_tgs_req.c b/src/kdc/do_tgs_req.c
|
|
index 6e4c8fa9f3..0acc45850f 100644
|
|
--- a/src/kdc/do_tgs_req.c
|
|
+++ b/src/kdc/do_tgs_req.c
|
|
@@ -1010,8 +1010,9 @@ tgs_issue_ticket(kdc_realm_t *realm, struct tgs_req_info *t,
|
|
}
|
|
|
|
if (t->req->kdc_options & (KDC_OPT_VALIDATE | KDC_OPT_RENEW)) {
|
|
- /* Copy the whole header ticket except for authorization data. */
|
|
- ticket_reply = *t->header_tkt;
|
|
+ /* Copy the header ticket server and all enc-part fields except for
|
|
+ * authorization data. */
|
|
+ ticket_reply.server = t->header_tkt->server;
|
|
enc_tkt_reply = *t->header_tkt->enc_part2;
|
|
enc_tkt_reply.authorization_data = NULL;
|
|
} else {
|
|
--
|
|
2.41.0
|
|
|