From: tb <tb@openbsd.org>
Date: Sun, 8 May 2022 14:07:35 +0000 (+0000)
Subject: Backport an upstream fix for CRC calculation. This fixes Java applications
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=c5288b00e8ac5cbc420f8ff5511281f46ecfb3f9;p=openbsd

Backport an upstream fix for CRC calculation. This fixes Java applications
on some older hardware, see https://github.com/madler/zlib/issues/613

Pointed out by tj and sthen

commit ec3df00224d4b396e2ac6586ab5d25f673caa4c2
Author: Mark Adler <madler@alumni.caltech.edu>
Date:   Wed Mar 30 11:14:53 2022 -0700

    Correct incorrect inputs provided to the CRC functions.

    The previous releases of zlib were not sensitive to incorrect CRC
    inputs with bits set above the low 32. This commit restores that
    behavior, so that applications with such bugs will continue to
    operate as before.
---

diff --git a/lib/libz/crc32.c b/lib/libz/crc32.c
index bd86dc13835..78c53e6a11b 100644
--- a/lib/libz/crc32.c
+++ b/lib/libz/crc32.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: crc32.c,v 1.10 2022/05/08 14:04:21 tb Exp $ */
+/*	$OpenBSD: crc32.c,v 1.11 2022/05/08 14:07:35 tb Exp $ */
 /* crc32.c -- compute the CRC-32 of a data stream
  * Copyright (C) 1995-2022 Mark Adler
  * For conditions of distribution and use, see copyright notice in zlib.h
@@ -629,7 +629,7 @@ unsigned long ZEXPORT crc32_z(crc, buf, len)
 #endif /* DYNAMIC_CRC_TABLE */
 
     /* Pre-condition the CRC */
-    crc ^= 0xffffffff;
+    crc = (~crc) & 0xffffffff;
 
     /* Compute the CRC up to a word boundary. */
     while (len && ((z_size_t)buf & 7) != 0) {
@@ -748,7 +748,7 @@ unsigned long ZEXPORT crc32_z(crc, buf, len)
 #endif /* DYNAMIC_CRC_TABLE */
 
     /* Pre-condition the CRC */
-    crc ^= 0xffffffff;
+    crc = (~crc) & 0xffffffff;
 
 #ifdef W
 
@@ -1076,7 +1076,7 @@ uLong ZEXPORT crc32_combine64(crc1, crc2, len2)
 #ifdef DYNAMIC_CRC_TABLE
     once(&made, make_crc_table);
 #endif /* DYNAMIC_CRC_TABLE */
-    return multmodp(x2nmodp(len2, 3), crc1) ^ crc2;
+    return multmodp(x2nmodp(len2, 3), crc1) ^ (crc2 & 0xffffffff);
 }
 
 /* ========================================================================= */
@@ -1111,5 +1111,5 @@ uLong crc32_combine_op(crc1, crc2, op)
     uLong crc2;
     uLong op;
 {
-    return multmodp(op, crc1) ^ crc2;
+    return multmodp(op, crc1) ^ (crc2 & 0xffffffff);
 }