From c22914f845b3eba1c9ad444333f3d044352b7e2c Mon Sep 17 00:00:00 2001
From: Joseph Sutton <josephsutton@catalyst.net.nz>
Date: Wed, 12 Oct 2022 13:57:13 +1300
Subject: [PATCH 08/15] CVE-2022-3437 source4/heimdal: Use constant-time
 memcmp() for arcfour unwrap

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>

[jsutton@samba.org Adapted to small differences in comparisons, and
 removed erroneous duplicate code in conflicting region]

Conflict: NA
Reference: https://download.samba.org/pub/samba/patches/security/samba-4.15.11-security-2022-10-25.patch
---
 source4/heimdal/lib/gssapi/krb5/arcfour.c | 24 +++++++----------------
 1 file changed, 7 insertions(+), 17 deletions(-)

diff --git a/source4/heimdal/lib/gssapi/krb5/arcfour.c b/source4/heimdal/lib/gssapi/krb5/arcfour.c
index a61f7686e95..c6b317ff683 100644
--- a/source4/heimdal/lib/gssapi/krb5/arcfour.c
+++ b/source4/heimdal/lib/gssapi/krb5/arcfour.c
@@ -385,9 +385,9 @@ _gssapi_verify_mic_arcfour(OM_uint32 * minor_status,
     _gsskrb5_decode_be_om_uint32(SND_SEQ, &seq_number);
 
     if (context_handle->more_flags & LOCAL)
-	cmp = memcmp(&SND_SEQ[4], "\xff\xff\xff\xff", 4);
+	cmp = ct_memcmp(&SND_SEQ[4], "\xff\xff\xff\xff", 4);
     else
-	cmp = memcmp(&SND_SEQ[4], "\x00\x00\x00\x00", 4);
+	cmp = ct_memcmp(&SND_SEQ[4], "\x00\x00\x00\x00", 4);
 
     memset(SND_SEQ, 0, sizeof(SND_SEQ));
     if (cmp != 0) {
@@ -656,9 +656,9 @@ OM_uint32 _gssapi_unwrap_arcfour(OM_uint32 *minor_status,
     _gsskrb5_decode_be_om_uint32(SND_SEQ, &seq_number);
 
     if (context_handle->more_flags & LOCAL)
-	cmp = memcmp(&SND_SEQ[4], "\xff\xff\xff\xff", 4);
+	cmp = ct_memcmp(&SND_SEQ[4], "\xff\xff\xff\xff", 4);
     else
-	cmp = memcmp(&SND_SEQ[4], "\x00\x00\x00\x00", 4);
+	cmp = ct_memcmp(&SND_SEQ[4], "\x00\x00\x00\x00", 4);
 
     if (cmp != 0) {
 	*minor_status = 0;
@@ -1266,19 +1266,9 @@ _gssapi_unwrap_iov_arcfour(OM_uint32 *minor_status,
     _gsskrb5_decode_be_om_uint32(snd_seq, &seq_number);
 
     if (ctx->more_flags & LOCAL) {
-	cmp = memcmp(&snd_seq[4], "\xff\xff\xff\xff", 4);
+	cmp = ct_memcmp(&snd_seq[4], "\xff\xff\xff\xff", 4);
     } else {
-	cmp = memcmp(&snd_seq[4], "\x00\x00\x00\x00", 4);
-    }
-    if (cmp != 0) {
-	*minor_status = 0;
-	return GSS_S_BAD_MIC;
-    }
-
-    if (ctx->more_flags & LOCAL) {
-	cmp = memcmp(&snd_seq[4], "\xff\xff\xff\xff", 4);
-    } else {
-	cmp = memcmp(&snd_seq[4], "\x00\x00\x00\x00", 4);
+	cmp = ct_memcmp(&snd_seq[4], "\x00\x00\x00\x00", 4);
     }
     if (cmp != 0) {
 	*minor_status = 0;
@@ -1353,7 +1343,7 @@ _gssapi_unwrap_iov_arcfour(OM_uint32 *minor_status,
 	return GSS_S_FAILURE;
     }
 
-    cmp = memcmp(cksum_data, p0 + 16, 8); /* SGN_CKSUM */
+    cmp = ct_memcmp(cksum_data, p0 + 16, 8); /* SGN_CKSUM */
     if (cmp != 0) {
 	*minor_status = 0;
 	return GSS_S_BAD_MIC;
-- 
2.25.1
