80034aeb78
Changed digest that is being stamped from $parent_commit_hash, to shaX(parent:$parent_commit_hash,tree:$tree_hash) where shaX is the hash function used by the repository. This change is so that the timestamp added also timestamps the LTV data that is being added with the timestamp commit. This LTV data now also contains CRLs for the LAST timestamp commit. This ensures that timestamp lifetime of old timestamps gets arbitrarily extended into the future with every new timestamp added to the repository. Further changes: -Updated documentation -updated schematics and changed from SVG to PNG -added assertions, pre- and post-conditions -added version number to timestamp commits as trailer -added hashing algorithm used as trailer -added digest being timestamped as trailer -added the string that is hashed to get the digest as traile -improved log messages of validate.sh
282 lines
14 KiB
Bash
282 lines
14 KiB
Bash
#!/bin/bash
|
|
#
|
|
# RFC3161 and RFC5816 Timestamping for git repositories.
|
|
#
|
|
# Copyright (c) 2021 Mabulous GmbH
|
|
# Authors: Matthias Bühlmann
|
|
#
|
|
# This program is free software: you can redistribute it and/or modify
|
|
# it under the terms of the GNU Affero General Public License as
|
|
# published by the Free Software Foundation, either version 3 of the
|
|
# License, or (at your option) any later version.
|
|
#
|
|
# This program is distributed in the hope that it will be useful,
|
|
# but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
# GNU Affero General Public License for more details.
|
|
#
|
|
# You should have received a copy of the GNU Affero General Public License
|
|
# along with this program. If not, see <https://www.gnu.org/licenses/>.
|
|
#
|
|
# The interactive user interfaces in modified source and object code versions
|
|
# of this program must display Appropriate Legal Notices, as required under
|
|
# Section 5 of the GNU Affero General Public License version 3. In accordance
|
|
# with Section 7(b) of the GNU Affero General Public License, you must retain
|
|
# the Info line in every timestamp that is created or manipulated using a
|
|
# covered work.
|
|
#
|
|
# You can be released from the requirements of the license by purchasing
|
|
# a commercial license. Buying such a license is mandatory as soon as you
|
|
# develop commercial activities involving this software without
|
|
# disclosing the source code of your own applications.
|
|
# These activities include: offering paid services to customers as an ASP,
|
|
# providing data storage and archival services, shipping this software with a
|
|
# closed source product.
|
|
#
|
|
# For more information, please contact Mabulous GmbH at this
|
|
# address: info@mabulous.com
|
|
#
|
|
|
|
DIR="${BASH_SOURCE%/*}"
|
|
if [[ ! -d "$DIR" ]]; then DIR="$PWD"; fi
|
|
. "$DIR/timestamping"
|
|
|
|
# If commit contains timestamp tokens, validates them.
|
|
# param1: commit hash
|
|
# returns: 0 if the commit contains no timestamp tokens or contains at least one
|
|
# valid timestamp token. If there are invalid timestamp tokens and no valid
|
|
# timestamp token, returns 1. If there are both valid and invalid timestamp
|
|
# tokens, the function will return 0 but echo a warning about the invalid token.
|
|
validate_commit() {
|
|
local COMMIT_HASH="$1"
|
|
log "validate_commit for $COMMIT_HASH"
|
|
|
|
local TIMESTAMP_COMMIT_VERSION
|
|
local URL_ARRAY
|
|
local TOKEN_ARRAY
|
|
if ! extract_token_from_commit "$COMMIT_HASH" "$TMP_DIR" TIMESTAMP_COMMIT_VERSION URL_ARRAY TOKEN_ARRAY; then
|
|
return 1
|
|
fi
|
|
local NUM_EXTRACTED="${#TOKEN_ARRAY[@]}"
|
|
|
|
if [ $NUM_EXTRACTED -eq 0 ];then
|
|
#this is not a timestamp commit
|
|
return 0
|
|
fi
|
|
|
|
local PARENT_HASH=$(git cat-file -p "$COMMIT_HASH" | awk '/^$/{exit} /parent/ {print}' | sed 's/parent //')
|
|
local TREE_HASH=$(git cat-file -p "$COMMIT_HASH" | awk '/^$/{exit} /tree/ {print}' | sed 's/tree //')
|
|
local EXPECTED_DIGEST
|
|
if [ $TIMESTAMP_COMMIT_VERSION -eq 0 ]; then
|
|
# version 0 timestamped directly the parent hash
|
|
EXPECTED_DIGEST="$PARENT_HASH"
|
|
else
|
|
# later versions add LTV data for last timestamp in the timestamp commit, so the tree is part of the digest
|
|
compute_digest_from_tree_and_parent "$TREE_HASH" "$PARENT_HASH" EXPECTED_DIGEST
|
|
fi
|
|
|
|
#iterate over extracted token
|
|
local ERROR_INFO_FILE="$TMP_DIR"/error_info.txt
|
|
local ERROR_INFO=""
|
|
local NUM_VALID=0
|
|
local NUM_INVALID=0
|
|
local EARLIEST_VALID_UNIX_TIME=-1
|
|
for (( i=0; i<"$NUM_EXTRACTED"; i++)); do
|
|
local TMP_TOKEN="${TOKEN_ARRAY[$i]}"
|
|
local DIGEST
|
|
get_token_digest "$TMP_TOKEN" DIGEST
|
|
if [ "${DIGEST,,}" != "${EXPECTED_DIGEST,,}" ]; then
|
|
echo_warning "Token from $TSA_URL in commit $COMMIT_HASH is invalid because the contained digest $DIGEST does not match the timestamped hash $EXPECTED_DIGEST"
|
|
((NUM_INVALID++))
|
|
continue
|
|
fi
|
|
local SIGNING_CERT_ID=''
|
|
get_tsa_cert_id "$TMP_TOKEN" SIGNING_CERT_ID
|
|
local TOKEN_UNIXTIME=''
|
|
get_token_unix_time "$TMP_TOKEN" TOKEN_UNIXTIME
|
|
local TSA_URL="${URL_ARRAY[$i]}"
|
|
local CERT_CHAIN_FILE="$LTV_DIR"/certs/"$SIGNING_CERT_ID".cer
|
|
if [ ! -f "$CERT_CHAIN_FILE" ]; then
|
|
#If LTV data is not in the working directory, try to check it out from the corresponding commit
|
|
local TMP_CERT_CHAIN_FILE="$TMP_DIR"/"$SIGNING_CERT_ID".cer
|
|
local PATH_SPEC=$(realpath --relative-to="$ROOT_DIR" "$CERT_CHAIN_FILE")
|
|
local CERT_CHAIN_CONTENT=$(git show "$COMMIT_HASH":"$PATH_SPEC") && printf "%s" "$CERT_CHAIN_CONTENT" > "$TMP_CERT_CHAIN_FILE"
|
|
CERT_CHAIN_FILE="$TMP_CERT_CHAIN_FILE"
|
|
fi
|
|
if [ ! -f "$CERT_CHAIN_FILE" ]; then
|
|
#if ltv data has not been stored for this commit, try to contact TSA to recreate it
|
|
if ! build_certificate_chain_for_token "$TMP_TOKEN" "$DIGEST" "$TSA_URL" "$CERT_CHAIN_FILE"; then
|
|
echo_warning "Token from $TSA_URL in commit $COMMIT_HASH could not be validated since neither LTV data of certificate chain could be found nor could the certificate chain be recreated from the TSA url."
|
|
((NUM_INVALID++))
|
|
continue
|
|
fi
|
|
fi
|
|
#$CERT_CHAIN_FILE at this point contains certificate chain of token's signing certificate.
|
|
#first validate the token itself at the time of timestamping
|
|
if ! openssl ts -verify -digest "$DIGEST" -in "$TMP_TOKEN" -token_in -attime "$TOKEN_UNIXTIME" \
|
|
-CApath "$CA_PATH" -untrusted "$CERT_CHAIN_FILE" 1> "$OUT_STREAM" 2> "$ERROR_INFO_FILE"; then
|
|
ERROR_INFO=$(cat "$ERROR_INFO_FILE")
|
|
echo_warning "Token from $TSA_URL in commit $COMMIT_HASH could not be validated since it is invalid or its rootCA isn't trusted: $ERROR_INFO"
|
|
((NUM_INVALID++))
|
|
continue
|
|
fi
|
|
|
|
#now validate the issuing certificate at the time of timestamping, using historical CRLs
|
|
local CRL_CHAIN_FILE="$LTV_DIR"/crls/"$SIGNING_CERT_ID".crl
|
|
local HISTORIC_CRL_CHAIN_FILE="$TMP_DIR"/"$SIGNING_CERT_ID".crl
|
|
local PATH_SPEC=$(realpath --relative-to="$ROOT_DIR" "$CRL_CHAIN_FILE")
|
|
local CRL_CHAIN_CONTENT=$(git show "$COMMIT_HASH":"$PATH_SPEC") && printf "%s" "$CRL_CHAIN_CONTENT" > "$HISTORIC_CRL_CHAIN_FILE"
|
|
if [ ! -f "$HISTORIC_CRL_CHAIN_FILE" ]; then
|
|
echo_warning "Token from $TSA_URL in commit $COMMIT_HASH could not be validated since no CRL data valid at the time of timestamping could be found."
|
|
((NUM_INVALID++))
|
|
continue
|
|
fi
|
|
#historic CRL data available, check if the signing certificate was valid at the time of timestamping
|
|
if ! openssl verify -attime "$TOKEN_UNIXTIME" -CApath "$CA_PATH" -CRLfile "$HISTORIC_CRL_CHAIN_FILE" \
|
|
-crl_check_all -untrusted "$CERT_CHAIN_FILE" "$CERT_CHAIN_FILE" 1> "$OUT_STREAM" 2> "$ERROR_INFO_FILE"; then
|
|
cat "$HISTORIC_CRL_CHAIN_FILE"
|
|
ERROR_INFO=$(cat "$ERROR_INFO_FILE")
|
|
echo_warning "Token from $TSA_URL in commit $COMMIT_HASH is invalid since TSA certificate has not been valid at the time the timestamp was created: $ERROR_INFO"
|
|
((NUM_INVALID++))
|
|
continue
|
|
fi
|
|
|
|
#now check that for each certificate in the trust chain a currently valid CRL can be found AND that
|
|
#each of the certificates either hasn't been revoked OR it has been revoked and the revocation entry contains the reasonCode
|
|
#extension and the reason code is one of unspecified (0), affiliationChanged (3), superseded (4) or cessationOfOperation (5) (see chapter 4 of https://www.ietf.org/rfc/rfc3161.txt)
|
|
local MOST_CURRENT_CRL_CHAIN_FILE="$TMP_DIR"/"$SIGNING_CERT_ID".crl
|
|
if ! download_crls_for_chain "$CERT_CHAIN_FILE" "$MOST_CURRENT_CRL_CHAIN_FILE"; then
|
|
echo_warning "Current CRLs for token could not be downloaded. Will try to use most recent CRL in LTV store".
|
|
if ! git show HEAD:"$CRL_CHAIN_FILE" > "$MOST_CURRENT_CRL_CHAIN_FILE"; then
|
|
echo_warning "Token from $TSA_URL in commit $COMMIT_HASH could not be validated since no currently valid CRL data could be found."
|
|
((NUM_INVALID++))
|
|
continue
|
|
fi
|
|
fi
|
|
#expand cert chain and crl chain into individual files
|
|
#remove files from previous runs
|
|
rm -f "$TMP_DIR"/*.extracted_cert.pem
|
|
rm -f "$TMP_DIR"/*.extracted_crl.pem
|
|
cat "$CERT_CHAIN_FILE" \
|
|
| awk '/-----BEGIN CERTIFICATE-----/ { i++; } /-----BEGIN CERTIFICATE-----/, /-----END CERTIFICATE-----/ \
|
|
{ print > tmpdir i ".extracted_cert.pem" }' tmpdir="$TMP_DIR/"
|
|
cat "$MOST_CURRENT_CRL_CHAIN_FILE" \
|
|
| awk '/-----BEGIN X509 CRL-----/ { i++; } /-----BEGIN X509 CRL-----/, /-----END X509 CRL-----/ \
|
|
{ print > tmpdir i ".extracted_crl.pem" }' tmpdir="$TMP_DIR/"
|
|
#iterate over extracted certificates (first is signing certificate, last is self-signed root)
|
|
while ls "$TMP_DIR"/*.extracted_cert.pem &> "$OUT_STREAM" && read EXTRACTED_CERT; do
|
|
if ! openssl verify -CApath "$CA_PATH" -CRLfile "$MOST_CURRENT_CRL_CHAIN_FILE" \
|
|
-crl_check -untrusted "$CERT_CHAIN_FILE" "$EXTRACTED_CERT" 1> "$OUT_STREAM" 2> "$ERROR_INFO_FILE"; then
|
|
ERROR_INFO=$(cat "$ERROR_INFO_FILE")
|
|
local -i ERROR_NUMBER=$(printf "%s" "$ERROR_INFO" | awk '/depth lookup/;' | sed 's/error //' | sed 's/ at.*//')
|
|
#local ERROR_DEPTH=$(cat error.txt | awk '/depth lookup/;' | sed 's/.*at //' | sed 's/ depth lookup.*//')
|
|
#error number must be
|
|
local -i X509_V_ERR_CERT_REVOKED=23
|
|
if [ $ERROR_NUMBER -ne $X509_V_ERR_CERT_REVOKED ]; then
|
|
echo_warning "Token from $TSA_URL in commit $COMMIT_HASH could not be validated since certificate validity could not be verified. Error: $ERROR_INFO."
|
|
((NUM_INVALID++))
|
|
continue 2
|
|
else
|
|
#find revocation reason
|
|
local CERT_SERIAL=$(openssl x509 -inform PEM -in "$EXTRACTED_CERT" -noout -serial | sed 's/serial=//')
|
|
local REVOCATION_ACCEPTABLE=false
|
|
local REASON=''
|
|
while ls "$TMP_DIR"/*.extracted_crl.pem &> "$OUT_STREAM" && read EXTRACTED_CRL; do
|
|
REASON=$(openssl crl -inform PEM -in "$EXTRACTED_CRL" -noout -text | awk '/$"CERT_SERIAL"/{f=1; next} f && /Serial Number:/{f=0} f && /CRL Reason Code:/{g=1; next} g {print; exit}' | sed 's/ *//')
|
|
if [ -z "$REASON" ]; then
|
|
continue
|
|
fi
|
|
#acceptable reasons: see chapter 4 of RFC3161
|
|
if [[ "$REASON" == "Unspecified" || "$REASON" == "Affiliation Changed" || "$REASON" == "Superseded" || "$REASON" == "Cessation Of Operation" ]]; then
|
|
REVOCATION_ACCEPTABLE=true
|
|
break
|
|
fi
|
|
done <<< $(ls "$TMP_DIR"/*.extracted_crl.pem 2> "$OUT_STREAM")
|
|
if [ "$REVOCATION_ACCEPTABLE" != true ]; then
|
|
if [ -z "$REASON" ]; then
|
|
REASON="Certificate revoked without reasonCode extension."
|
|
fi
|
|
echo_warning "Token from $TSA_URL in commit $COMMIT_HASH is invalid since certificate was revoked for the following reason: $REASON"
|
|
((NUM_INVALID++))
|
|
continue 2
|
|
fi
|
|
fi
|
|
fi
|
|
done <<< $(ls "$TMP_DIR"/*.extracted_cert.pem 2> "$OUT_STREAM")
|
|
#token is valid
|
|
if [ $EARLIEST_VALID_UNIX_TIME -eq -1 ] || [ $TOKEN_UNIXTIME -lt $EARLIEST_VALID_UNIX_TIME ];then
|
|
EARLIEST_VALID_UNIX_TIME=$TOKEN_UNIXTIME
|
|
fi
|
|
((NUM_VALID++))
|
|
done #for loop
|
|
local NUM_PROCESSED=$(( $NUM_VALID + $NUM_INVALID ))
|
|
#assert that all extracted timestamps have been processed
|
|
assert "[ $NUM_PROCESSED -eq $NUM_EXTRACTED ]" "All extracted token must be processed."
|
|
|
|
if [ $NUM_VALID -gt 0 ]; then
|
|
if [ $NUM_INVALID -gt 0 ]; then
|
|
echo_warning "Warning: While commit $COMMIT_HASH contains $NUM_VALID valid timestamp tokens and thus is considered proppely timestamped, it also contains $NUM_INVALID invalid timestamp tokens."
|
|
fi
|
|
DATE_STRING=$(date -d @"$EARLIEST_VALID_UNIX_TIME")
|
|
echo_info "Commit $COMMIT_HASH, which timestamps commit $PARENT_HASH at $DATE_STRING, contains $NUM_VALID valid timestamp tokens."
|
|
echo ""
|
|
return 0
|
|
fi
|
|
echo_error "All $NUM_EXTRACTED timestamp tokens in commit $COMMIT_HASH are invalid."
|
|
return 1
|
|
}
|
|
|
|
# Recursive function to validate all ancestors of commit
|
|
# param1: commit hash
|
|
# returns: 0 if the validation of the commit and all its ancestors succeeded
|
|
validate_commit_and_parents() {
|
|
local COMMIT_HASH="$1"
|
|
log "validate_commit_and_parents for $COMMIT_HASH"
|
|
|
|
local ALL_PASSED=true
|
|
if ! validate_commit "$COMMIT_HASH"; then
|
|
ALL_PASSED=false
|
|
fi
|
|
local PARENTS=$(git cat-file -p "$COMMIT_HASH" | awk '/^$/{exit} /parent/ {print}' | sed 's/parent //')
|
|
#iterate over all parents of commit
|
|
if [ ! -z "$PARENTS" ]; then
|
|
while read PARENT_HASH; do
|
|
if ! validate_commit_and_parents "$PARENT_HASH"; then
|
|
ALL_PASSED=false
|
|
fi
|
|
done <<< $(printf "%s" "$PARENTS")
|
|
fi
|
|
if [ "$ALL_PASSED"=true ]; then
|
|
return 0
|
|
fi
|
|
return 1
|
|
}
|
|
|
|
OBJECT="$1"
|
|
if [ -z "$OBJECT" ]; then
|
|
OBJECT="HEAD"
|
|
fi
|
|
COMMIT_HASH=$(git rev-parse "$OBJECT")
|
|
if [ -z "$COMMIT_HASH" ]; then
|
|
echo_error "Invalid rev $OBJECT"
|
|
return 1
|
|
fi
|
|
|
|
echo_info "Checking repository integrity..."
|
|
#check git repository integrity
|
|
if ! git fsck --full --strict --no-progress --no-dangling "$COMMIT_HASH"; then
|
|
echo_error "git fsck failed. This means the repository is in a corrupted state and cannot be validated. Restore corrupt files from a backup or remote repository."
|
|
exit 1
|
|
fi
|
|
echo_info "Repository integrity OK"
|
|
echo ""
|
|
|
|
echo_info "Validating timestamps. This may take a while..."
|
|
echo ""
|
|
if validate_commit_and_parents "$COMMIT_HASH"; then
|
|
echo_info "Validation OK: All timestamped commits in the commit history of $COMMIT_HASH contain at least one valid timestamp."
|
|
exit 0
|
|
else
|
|
echo_error "Validation Failed: There are timestamped commits in the commit history of $COMMIT_HASH which do not contain any valid timestamps."
|
|
exit 1
|
|
fi |