From 8fb508a25a6a47289c73e3f4339352a73a396eef Mon Sep 17 00:00:00 2001
From: Joseph Sutton <josephsutton@catalyst.net.nz>
Date: Wed, 12 Oct 2022 13:57:33 +1300
Subject: [PATCH] gsskrb5: CVE-2022-3437 Pass correct length to
 _gssapi_verify_pad()

We later subtract 8 when calculating the length of the output message
buffer. If padlength is excessively high, this calculation can underflow
and result in a very large positive value.

Now we properly constrain the value of padlength so underflow shouldn't
be possible.

Samba BUG: https://bugzilla.samba.org/show_bug.cgi?id=15134

Signed-off-by: Joseph Sutton <josephsutton@catalyst.net.nz>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>

Upstream-Status: Backport [https://github.com/heimdal/heimdal/commit/8fb508a25a6a47289c73e3f4339352a73a396eef]
CVE: CVE-2022-3437

Signed-off-by: Archana Polampalli <archana.polampalli@windriver.com>
---
 lib/gssapi/krb5/unwrap.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/gssapi/krb5/unwrap.c b/lib/gssapi/krb5/unwrap.c
index fddb64bc53..bab30f4501 100644
--- a/lib/gssapi/krb5/unwrap.c
+++ b/lib/gssapi/krb5/unwrap.c
@@ -124,7 +124,7 @@ unwrap_des
   } else {
     /* check pad */
     ret = _gssapi_verify_pad(input_message_buffer,
-			     input_message_buffer->length - len,
+			     input_message_buffer->length - len - 8,
			     &padlength);
     if (ret)
         return ret;
@@ -289,7 +289,7 @@ unwrap_des3
   } else {
     /* check pad */
     ret = _gssapi_verify_pad(input_message_buffer,
-			     input_message_buffer->length - len,
+			     input_message_buffer->length - len - 8,
			     &padlength);
     if (ret)
         return ret;
