test(gateway): pin what the CA refuses, not only what it accepts

The phase proved a certificate issues from a published record. It could not
prove the record had to be that record: the only failing case it exercised was
the domain having no record at all.

Three cases the CA now decides, because it looks the record up rather than
being run with PEBBLE_VA_ALWAYS_VALID:

- A record correct in every respect except `policy=wildcard` does not answer
  the order. The gateway only ever orders `*.{domain}`, so every authorization
  it answers is a wildcard one, and the draft has a CA accept those only from
  a record carrying the parameter.
- Adding that one parameter, and nothing else, issues. Without this the case
  above could pass for any reason at all.
- A record naming a different account does not authorize. If it did, the
  record would authorize anybody who found it and the challenge would prove
  nothing.

Plus the two gateway operations that change shape for a domain the gateway
cannot write: `SetCaa` skips it rather than failing the whole run or writing
to a provider it has no credential for, and `RotateAcmeCredentials` returns
the records to republish, naming the account it just registered -- the old
records name the account it replaced, and nothing else reports them.

Each refusal gets its own domain. `DeleteZtDomain` keeps the certificate on
purpose, so a domain that has already issued reports that certificate after
being re-added, and a refusal would read as a pass. The assertions are
inverted rather than matched against an error string, because what is being
claimed is that no certificate appears.

Author: kvinwang

dstack/gateway/test-run/e2e/docker-compose.yml

@@ -51,7 +51,7 @@ services:
       - PORT=8080
       - DEBUG=true
       # The zones certbot writes into and Pebble reads back out of.
-      - MOCK_CF_ZONES=test0.local,test1.local,test2.local,persist0.local
+      - MOCK_CF_ZONES=test0.local,test1.local,test2.local,persist0.local,persist1.local,persist2.local
     healthcheck:
       test: ["CMD", "python", "-c", "import urllib.request; urllib.request.urlopen('http://localhost:8080/health')"]
       interval: 5s

dstack/gateway/test-run/e2e/test.sh

@@ -41,6 +41,19 @@ PERSIST_DOMAIN="persist0.local"
 # Mock zone ID, as server.py derives it from the zone name.
 PERSIST_ZONE_ID="zone-persist0-local"
 
+# A second dns-persist-01 domain, used for the cases that must NOT issue. Kept
+# apart from PERSIST_DOMAIN so a deliberately unanswerable order cannot be
+# confused with the working one.
+PERSIST_NEG_DOMAIN="persist1.local"
+PERSIST_NEG_ZONE_ID="zone-persist1-local"
+
+# A third domain, for the second refusal. Deleting a ZT domain deliberately
+# keeps its certificate ("kept for historical purposes"), so reusing a domain
+# that has already issued would report the old certificate and read as a
+# refusal that did not happen.
+PERSIST_NEG2_DOMAIN="persist2.local"
+PERSIST_NEG2_ZONE_ID="zone-persist2-local"
+
 # Pebble answers to this name, not to letsencrypt.org, and a validation record
 # naming a CA the challenge does not list is ignored.
 PERSIST_ISSUER="pebble.letsencrypt.org"
@@ -232,6 +245,135 @@ test_persist_domain_issues_a_certificate() {
     return 1
 }
 
+# ---- Cases that must NOT issue -------------------------------------------
+#
+# These are the reason the mock answers DNS at all. With PEBBLE_VA_ALWAYS_VALID
+# the CA accepts any challenge, so a wrong record and a right one are
+# indistinguishable and the record's grammar is pinned only by unit tests
+# written against a reading of the CA. Here the CA reads it.
+
+# Publish one TXT record verbatim at the negative domain's validation name,
+# replacing whatever is there.
+publish_neg_record() {
+    local domain="$1" zone="$2" rdata="$3"
+    local records id
+    records=$(curl -sf "${MOCK_CF_API}/api/records" 2>/dev/null || echo '{"records":[]}')
+    for id in $(echo "$records" \
+        | tr '{' '\n' \
+        | grep -F "_validation-persist.${domain}" \
+        | sed -e 's/.*"id": "//' -e 's/".*//'); do
+        curl -sf -X DELETE \
+            "${MOCK_CF_API}/client/v4/zones/${zone}/dns_records/${id}" \
+            -H "Authorization: Bearer ${CF_API_TOKEN}" > /dev/null 2>&1 || true
+    done
+    curl -sf -X POST "${MOCK_CF_API}/client/v4/zones/${zone}/dns_records" \
+        -H "Authorization: Bearer ${CF_API_TOKEN}" \
+        -H "Content-Type: application/json" \
+        -d '{
+            "type": "TXT",
+            "name": "_validation-persist.'"${domain}"'",
+            "content": "'"${rdata}"'",
+            "ttl": 1
+        }' > /dev/null
+}
+
+# The account URI the cluster actually holds, read off the domain the gateway
+# already renders records for.
+persist_account_uri() {
+    admin_post GetZtDomain '{"domain": "'"${PERSIST_DOMAIN}"'"}' \
+        | tr ',' '\n' \
+        | grep -F "accounturi=" \
+        | head -1 \
+        | sed -e 's/.*accounturi=//' -e 's/[";\\].*//'
+}
+
+# Try to issue for the negative domain and report whether a certificate
+# appeared. Deliberately short: the interesting outcome is "no certificate",
+# and an order that is going to be refused says so in one pass.
+neg_domain_issued() {
+    local domain="$1"
+    admin_post RenewZtDomainCert \
+        '{"domain": "'"${domain}"'", "force": true}' > /dev/null 2>&1 || true
+    local i=0
+    while [ $i -lt 45 ]; do
+        if admin_post GetZtDomain '{"domain": "'"${domain}"'"}' \
+            | grep -q '"has_cert":true'; then
+            return 0
+        fi
+        sleep 2
+        i=$((i + 1))
+    done
+    return 1
+}
+
+# The gateway only ever orders `*.{domain}`, so every authorization it answers
+# is a wildcard one -- and the draft has a CA accept a wildcard authorization
+# only from a record carrying `policy=wildcard`. A record that is correct in
+# every other respect must therefore not be enough.
+test_persist_record_without_wildcard_policy_is_refused() {
+    admin_post DeleteZtDomain '{"domain": "'"${PERSIST_NEG_DOMAIN}"'"}' > /dev/null 2>&1 || true
+    admin_post AddZtDomain \
+        '{"domain": "'"${PERSIST_NEG_DOMAIN}"'", "port": 443, "challenge": "dns-persist-01"}' \
+        > /dev/null || return 1
+    local uri
+    uri=$(persist_account_uri) || return 1
+    [ -n "$uri" ] || return 1
+    publish_neg_record "${PERSIST_NEG_DOMAIN}" "${PERSIST_NEG_ZONE_ID}" \
+        "${PERSIST_ISSUER}; accounturi=${uri}" || return 1
+    # Inverted: issuing here would mean the policy parameter is not enforced.
+    ! neg_domain_issued "${PERSIST_NEG_DOMAIN}"
+}
+
+# Adding the one parameter that was missing, and nothing else, has to flip the
+# outcome. That is what makes the previous case a statement about `policy`
+# rather than about some unrelated breakage.
+test_persist_record_with_wildcard_policy_issues() {
+    local uri
+    uri=$(persist_account_uri) || return 1
+    publish_neg_record "${PERSIST_NEG_DOMAIN}" "${PERSIST_NEG_ZONE_ID}" \
+        "${PERSIST_ISSUER}; accounturi=${uri}; policy=wildcard" || return 1
+    neg_domain_issued "${PERSIST_NEG_DOMAIN}"
+}
+
+# The account URI in the record is the whole authorization. A record naming a
+# different account must not let this one issue -- otherwise publishing a record
+# authorizes anybody, and the challenge proves nothing.
+test_persist_record_for_another_account_is_refused() {
+    admin_post DeleteZtDomain '{"domain": "'"${PERSIST_NEG2_DOMAIN}"'"}' > /dev/null 2>&1 || true
+    admin_post AddZtDomain \
+        '{"domain": "'"${PERSIST_NEG2_DOMAIN}"'", "port": 443, "challenge": "dns-persist-01"}' \
+        > /dev/null || return 1
+    publish_neg_record "${PERSIST_NEG2_DOMAIN}" "${PERSIST_NEG2_ZONE_ID}" \
+        "${PERSIST_ISSUER}; accounturi=${ACME_URL%/dir}/my-account/0; policy=wildcard" || return 1
+    ! neg_domain_issued "${PERSIST_NEG2_DOMAIN}"
+}
+
+# ---- Gateway operations that change shape for such a domain ---------------
+
+# SetCaa reconciles CAA through the DNS provider, which the gateway has no
+# credential for here. It must skip the domain rather than fail the call, and
+# must not write anything.
+test_set_caa_skips_a_persist_domain() {
+    admin_post SetCaa '{}' > /dev/null 2>&1 || true
+    local records
+    records=$(curl -sf "${MOCK_CF_API}/api/records" 2>/dev/null || echo "[]")
+    ! echo "$records" | grep -qF "\"type\": \"CAA\", \"name\": \"${PERSIST_DOMAIN}"
+}
+
+# Rotation registers a new account, and every published record names the old
+# one. The response has to carry the replacements, because the gateway cannot
+# publish them and nothing else reports them.
+test_rotation_reports_the_records_to_republish() {
+    local out
+    out=$(admin_post RotateAcmeCredentials '{}') || return 1
+    echo "$out" | grep -qF "_validation-persist.${PERSIST_DOMAIN}" || return 1
+    # Naming the new account, not the one it replaced.
+    local uri
+    uri=$(echo "$out" | sed -e 's/.*"account_uri": *"//' -e 's/".*//')
+    [ -n "$uri" ] || return 1
+    echo "$out" | grep -qF "accounturi=${uri}"
+}
+
 # The claim the whole challenge exists for: certbot reads DNS and never writes
 # it. Scoped to the record certbot would have written -- the zone is not empty,
 # because the harness published the validation record above standing in for the
@@ -491,6 +633,20 @@ main() {
     run_test "No DNS record is ever written for it" \
         "$(test_persist_domain_never_touches_the_provider; echo $?)"
 
+    # What the CA refuses, now that it actually looks the record up.
+    run_test "A record without policy=wildcard cannot answer a wildcard order" \
+        "$(test_persist_record_without_wildcard_policy_is_refused; echo $?)"
+    run_test "Adding policy=wildcard is what makes it answerable" \
+        "$(test_persist_record_with_wildcard_policy_issues; echo $?)"
+    run_test "A record naming another account does not authorize" \
+        "$(test_persist_record_for_another_account_is_refused; echo $?)"
+
+    # Gateway operations that change shape for a domain it cannot write.
+    run_test "SetCaa skips it instead of failing or writing" \
+        "$(test_set_caa_skips_a_persist_domain; echo $?)"
+    run_test "Rotation reports the records to republish" \
+        "$(test_rotation_reports_the_records_to_republish; echo $?)"
+
     # Summary
     log_section "Test Summary"
     log_info "Passed: $TESTS_PASSED"