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From ef08b09c9459551aabbe7924fb176f1583053cdd Mon Sep 17 00:00:00 2001
From: Greg Hudson <ghudson@mit.edu>
Date: Wed, 21 Jun 2023 10:57:39 -0400
Subject: [PATCH] Ensure array count consistency in kadm5 RPC
In _xdr_kadm5_principal_ent_rec(), ensure that n_key_data matches the
key_data array count when decoding. Otherwise when the structure is
later freed, xdr_array() could iterate over the wrong number of
elements, either leaking some memory or freeing uninitialized
pointers. Reported by Robert Morris.
CVE-2023-36054:
An authenticated attacker can cause a kadmind process to crash by
freeing uninitialized pointers. Remote code execution is unlikely.
An attacker with control of a kadmin server can cause a kadmin client
to crash by freeing uninitialized pointers.
ticket: 9099 (new)
tags: pullup
target_version: 1.21-next
target_version: 1.20-next
---
src/lib/kadm5/kadm_rpc_xdr.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)
diff --git a/src/lib/kadm5/kadm_rpc_xdr.c b/src/lib/kadm5/kadm_rpc_xdr.c
index 0411c3fd3f4..287cae750f9 100644
--- a/src/lib/kadm5/kadm_rpc_xdr.c
+++ b/src/lib/kadm5/kadm_rpc_xdr.c
@@ -390,6 +390,7 @@ _xdr_kadm5_principal_ent_rec(XDR *xdrs, kadm5_principal_ent_rec *objp,
int v)
{
unsigned int n;
+ bool_t r;
if (!xdr_krb5_principal(xdrs, &objp->principal)) {
return (FALSE);
@@ -443,6 +444,9 @@ _xdr_kadm5_principal_ent_rec(XDR *xdrs, kadm5_principal_ent_rec *objp,
if (!xdr_krb5_int16(xdrs, &objp->n_key_data)) {
return (FALSE);
}
+ if (xdrs->x_op == XDR_DECODE && objp->n_key_data < 0) {
+ return (FALSE);
+ }
if (!xdr_krb5_int16(xdrs, &objp->n_tl_data)) {
return (FALSE);
}
@@ -451,9 +455,10 @@ _xdr_kadm5_principal_ent_rec(XDR *xdrs, kadm5_principal_ent_rec *objp,
return FALSE;
}
n = objp->n_key_data;
- if (!xdr_array(xdrs, (caddr_t *) &objp->key_data,
- &n, ~0, sizeof(krb5_key_data),
- xdr_krb5_key_data_nocontents)) {
+ r = xdr_array(xdrs, (caddr_t *) &objp->key_data, &n, objp->n_key_data,
+ sizeof(krb5_key_data), xdr_krb5_key_data_nocontents);
+ objp->n_key_data = n;
+ if (!r) {
return (FALSE);
}
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