1#!/bin/sh
2#
3# Licensed to the Apache Software Foundation (ASF) under one
4# or more contributor license agreements.  See the NOTICE file
5# distributed with this work for additional information
6# regarding copyright ownership.  The ASF licenses this file
7# to you under the Apache License, Version 2.0 (the
8# "License"); you may not use this file except in compliance
9# with the License.  You may obtain a copy of the License at
10#
11#   http://www.apache.org/licenses/LICENSE-2.0
12#
13# Unless required by applicable law or agreed to in writing,
14# software distributed under the License is distributed on an
15# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
16# KIND, either express or implied.  See the License for the
17# specific language governing permissions and limitations
18# under the License.
19#
20#
21# $Id: reject-known-sha1-collisions.sh 1784763 2017-02-28 15:40:00Z stsp $
22#
23# Prevents some SHA-1 collisions to be committed
24# Test for the 320 byte prefix found on https://shattered.io/
25# If the files are committed in the same transaction, svnlook
26# will error out itself due to the apparent corruption in the
27# candidate revision
28
29REPOS="$1"
30TXN="$2"
31SVNLOOK=/usr/bin/svnlook
32GREP=/usr/bin/grep
33SED=/usr/bin/sed
34# GNU coreutils versions of these tools are required:
35SHA1SUM=/usr/bin/sha1sum
36HEAD=/usr/bin/head
37
38$SVNLOOK changed -t "$TXN" "$REPOS"
39if [ $? -ne 0 ]; then
40  echo "svnlook failed, possible SHA-1 collision" >&2
41  exit 2
42fi
43
44$SVNLOOK changed -t "$TXN" "$REPOS" | $GREP -Ev '^D ' | $SED -e 's/^.   //' | $GREP -v '/$' | while IFS= read -r FILE; do
45  PREFIX=`$SVNLOOK cat -t "$TXN" "$REPOS" "$FILE" | $HEAD -c320 | $SHA1SUM | cut -c-40`
46  if [ x"$PREFIX" = x'f92d74e3874587aaf443d1db961d4e26dde13e9c' ]; then
47        echo "known SHA-1 collision rejected" >&2
48        exit 3
49  fi
50done
51