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httpcaddyfile: Revise automation policy generation #3824

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Oct 29, 2020
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httpcaddyfile: Revise automation policy generation #3824

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a1bebfd
httpcaddyfile: Revise automation policy generation
mholt Oct 28, 2020
4dcce1d
Fix typo
mholt Oct 28, 2020
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295 changes: 165 additions & 130 deletions caddyconfig/httpcaddyfile/tlsapp.go
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Original file line number Diff line number Diff line change
Expand Up @@ -76,44 +76,42 @@ func (st ServerType) buildTLSApp(
}
}

// a catch-all automation policy is used as a "default" for all subjects that
// don't have custom configuration explicitly associated with them; this
// is only to add if the global settings or defaults are non-empty
catchAllAP, err := newBaseAutomationPolicy(options, warnings, false)
if err != nil {
return nil, warnings, err
}
if catchAllAP != nil {
if tlsApp.Automation == nil {
tlsApp.Automation = new(caddytls.AutomationConfig)
}
tlsApp.Automation.Policies = append(tlsApp.Automation.Policies, catchAllAP)
}

for _, p := range pairings {
for _, sblock := range p.serverBlocks {
// get values that populate an automation policy for this block
var ap *caddytls.AutomationPolicy
ap, err := newBaseAutomationPolicy(options, warnings, true)
if err != nil {
return nil, warnings, err
}

sblockHosts := sblock.hostsFromKeys(false)
if len(sblockHosts) == 0 {
if len(sblockHosts) == 0 && catchAllAP != nil {
ap = catchAllAP
}

// on-demand tls
if _, ok := sblock.pile["tls.on_demand"]; ok {
if ap == nil {
var err error
ap, err = newBaseAutomationPolicy(options, warnings, true)
if err != nil {
return nil, warnings, err
}
}
ap.OnDemand = true
}

// certificate issuers
if issuerVals, ok := sblock.pile["tls.cert_issuer"]; ok {
for _, issuerVal := range issuerVals {
issuer := issuerVal.Value.(certmagic.Issuer)
if ap == nil {
var err error
ap, err = newBaseAutomationPolicy(options, warnings, true)
if err != nil {
return nil, warnings, err
}
}
if ap == catchAllAP && !reflect.DeepEqual(ap.Issuer, issuer) {
return nil, warnings, fmt.Errorf("automation policy from site block is also default/catch-all policy because of key without hostname, and the two are in conflict: %#v != %#v", ap.Issuer, issuer)
}
Expand All @@ -123,15 +121,6 @@ func (st ServerType) buildTLSApp(

// custom bind host
for _, cfgVal := range sblock.pile["bind"] {
// either an existing issuer is already configured (and thus, ap is not
// nil), or we need to configure an issuer, so we need ap to be non-nil
if ap == nil {
ap, err = newBaseAutomationPolicy(options, warnings, true)
if err != nil {
return nil, warnings, err
}
}

// if an issuer was already configured and it is NOT an ACME
// issuer, skip, since we intend to adjust only ACME issuers
var acmeIssuer *caddytls.ACMEIssuer
Expand Down Expand Up @@ -164,87 +153,74 @@ func (st ServerType) buildTLSApp(
ap.Issuer = acmeIssuer // we'll encode it later
}

if ap != nil {
if ap.Issuer != nil {
// encode issuer now that it's all set up
issuerName := ap.Issuer.(caddy.Module).CaddyModule().ID.Name()
ap.IssuerRaw = caddyconfig.JSONModuleObject(ap.Issuer, "module", issuerName, &warnings)
// first make sure this block is allowed to create an automation policy;
// doing so is forbidden if it has a key with no host (i.e. ":443")
// and if there is a different server block that also has a key with no
// host -- since a key with no host matches any host, we need its
// associated automation policy to have an empty Subjects list, i.e. no
// host filter, which is indistinguishable between the two server blocks
// because automation is not done in the context of a particular server...
// this is an example of a poor mapping from Caddyfile to JSON but that's
// the least-leaky abstraction I could figure out
if len(sblockHosts) == 0 {
if serverBlocksWithTLSHostlessKey > 1 {
// this server block and at least one other has a key with no host,
// making the two indistinguishable; it is misleading to define such
// a policy within one server block since it actually will apply to
// others as well
return nil, warnings, fmt.Errorf("cannot make a TLS automation policy from a server block that has a host-less address when there are other TLS-enabled server block addresses lacking a host")
}

// first make sure this block is allowed to create an automation policy;
// doing so is forbidden if it has a key with no host (i.e. ":443")
// and if there is a different server block that also has a key with no
// host -- since a key with no host matches any host, we need its
// associated automation policy to have an empty Subjects list, i.e. no
// host filter, which is indistinguishable between the two server blocks
// because automation is not done in the context of a particular server...
// this is an example of a poor mapping from Caddyfile to JSON but that's
// the least-leaky abstraction I could figure out
if len(sblockHosts) == 0 {
if serverBlocksWithTLSHostlessKey > 1 {
// this server block and at least one other has a key with no host,
// making the two indistinguishable; it is misleading to define such
// a policy within one server block since it actually will apply to
// others as well
return nil, warnings, fmt.Errorf("cannot make a TLS automation policy from a server block that has a host-less address when there are other TLS-enabled server block addresses lacking a host")
}
if catchAllAP == nil {
// this server block has a key with no hosts, but there is not yet
// a catch-all automation policy (probably because no global options
// were set), so this one becomes it
catchAllAP = ap
}
if catchAllAP == nil {
// this server block has a key with no hosts, but there is not yet
// a catch-all automation policy (probably because no global options
// were set), so this one becomes it
catchAllAP = ap
}
}

// associate our new automation policy with this server block's hosts,
// unless, of course, the server block has a key with no hosts, in which
// case its automation policy becomes or blends with the default/global
// automation policy because, of necessity, it applies to all hostnames
// (i.e. it has no Subjects filter) -- in that case, we'll append it last
if ap != catchAllAP {
ap.Subjects = sblockHosts

// if a combination of public and internal names were given
// for this same server block and no issuer was specified, we
// need to separate them out in the automation policies so
// that the internal names can use the internal issuer and
// the other names can use the default/public/ACME issuer
var ap2 *caddytls.AutomationPolicy
if ap.Issuer == nil {
var internal, external []string
for _, s := range ap.Subjects {
if !certmagic.SubjectQualifiesForCert(s) {
return nil, warnings, fmt.Errorf("subject does not qualify for certificate: '%s'", s)
}
// we don't use certmagic.SubjectQualifiesForPublicCert() because of one nuance:
// names like *.*.tld that may not qualify for a public certificate are actually
// fine when used with OnDemand, since OnDemand (currently) does not obtain
// wildcards (if it ever does, there will be a separate config option to enable
// it that we would need to check here) since the hostname is known at handshake;
// and it is unexpected to switch to internal issuer when the user wants to get
// regular certificates on-demand for a class of certs like *.*.tld.
if !certmagic.SubjectIsIP(s) && !certmagic.SubjectIsInternal(s) && (strings.Count(s, "*.") < 2 || ap.OnDemand) {
external = append(external, s)
} else {
internal = append(internal, s)
}
}
if len(external) > 0 && len(internal) > 0 {
ap.Subjects = external
apCopy := *ap
ap2 = &apCopy
ap2.Subjects = internal
ap2.IssuerRaw = caddyconfig.JSONModuleObject(caddytls.InternalIssuer{}, "module", "internal", &warnings)
}
// associate our new automation policy with this server block's hosts
ap.Subjects = sblockHosts
sort.Strings(ap.Subjects) // solely for deterministic test results

// if a combination of public and internal names were given
// for this same server block and no issuer was specified, we
// need to separate them out in the automation policies so
// that the internal names can use the internal issuer and
// the other names can use the default/public/ACME issuer
var ap2 *caddytls.AutomationPolicy
if ap.Issuer == nil {
var internal, external []string
for _, s := range ap.Subjects {
if !certmagic.SubjectQualifiesForCert(s) {
return nil, warnings, fmt.Errorf("subject does not qualify for certificate: '%s'", s)
}
if tlsApp.Automation == nil {
tlsApp.Automation = new(caddytls.AutomationConfig)
}
tlsApp.Automation.Policies = append(tlsApp.Automation.Policies, ap)
if ap2 != nil {
tlsApp.Automation.Policies = append(tlsApp.Automation.Policies, ap2)
// we don't use certmagic.SubjectQualifiesForPublicCert() because of one nuance:
// names like *.*.tld that may not qualify for a public certificate are actually
// fine when used with OnDemand, since OnDemand (currently) does not obtain
// wildcards (if it ever does, there will be a separate config option to enable
// it that we would need to check here) since the hostname is known at handshake;
// and it is unexpected to switch to internal issuer when the user wants to get
// regular certificates on-demand for a class of certs like *.*.tld.
if !certmagic.SubjectIsIP(s) && !certmagic.SubjectIsInternal(s) && (strings.Count(s, "*.") < 2 || ap.OnDemand) {
external = append(external, s)
} else {
internal = append(internal, s)
}
}
if len(external) > 0 && len(internal) > 0 {
ap.Subjects = external
apCopy := *ap
ap2 = &apCopy
ap2.Subjects = internal
ap2.IssuerRaw = caddyconfig.JSONModuleObject(caddytls.InternalIssuer{}, "module", "internal", &warnings)
}
}
if tlsApp.Automation == nil {
tlsApp.Automation = new(caddytls.AutomationConfig)
}
tlsApp.Automation.Policies = append(tlsApp.Automation.Policies, ap)
if ap2 != nil {
tlsApp.Automation.Policies = append(tlsApp.Automation.Policies, ap2)
}

// certificate loaders
Expand Down Expand Up @@ -319,23 +295,17 @@ func (st ServerType) buildTLSApp(
tlsApp.Automation.Policies = append(tlsApp.Automation.Policies, internalAP)
}

// if there is a global/catch-all automation policy, ensure it goes last
if catchAllAP != nil {
// first, encode its issuer, if there is one
if catchAllAP.Issuer != nil {
issuerName := catchAllAP.Issuer.(caddy.Module).CaddyModule().ID.Name()
catchAllAP.IssuerRaw = caddyconfig.JSONModuleObject(catchAllAP.Issuer, "module", issuerName, &warnings)
}

// then append it to the end of the policies list
if tlsApp.Automation == nil {
tlsApp.Automation = new(caddytls.AutomationConfig)
// finalize and verify policies; do cleanup
if tlsApp.Automation != nil {
// encode any issuer values we created, so they will be rendered in the output
for _, ap := range tlsApp.Automation.Policies {
if ap.Issuer != nil && ap.IssuerRaw == nil {
// encode issuer now that it's all set up
issuerName := ap.Issuer.(caddy.Module).CaddyModule().ID.Name()
ap.IssuerRaw = caddyconfig.JSONModuleObject(ap.Issuer, "module", issuerName, &warnings)
}
}
tlsApp.Automation.Policies = append(tlsApp.Automation.Policies, catchAllAP)
}

// do a little verification & cleanup
if tlsApp.Automation != nil {
// consolidate automation policies that are the exact same
tlsApp.Automation.Policies = consolidateAutomationPolicies(tlsApp.Automation.Policies)

Expand All @@ -351,6 +321,14 @@ func (st ServerType) buildTLSApp(
automationHostSet[s] = struct{}{}
}
}

// if nothing remains, remove any excess values to clean up the resulting config
if len(tlsApp.Automation.Policies) == 0 {
tlsApp.Automation.Policies = nil
}
if reflect.DeepEqual(tlsApp.Automation, new(caddytls.AutomationConfig)) {
tlsApp.Automation = nil
}
}

return tlsApp, warnings, nil
Expand Down Expand Up @@ -448,12 +426,30 @@ func disambiguateACMEIssuer(acmeIssuer *caddytls.ACMEIssuer) certmagic.Issuer {
// consolidateAutomationPolicies combines automation policies that are the same,
// for a cleaner overall output.
func consolidateAutomationPolicies(aps []*caddytls.AutomationPolicy) []*caddytls.AutomationPolicy {
// sort from most specific to least specific; we depend on this ordering
sort.SliceStable(aps, func(i, j int) bool {
if automationPolicyIsSubset(aps[i], aps[j]) {
return true
}
if automationPolicyIsSubset(aps[j], aps[i]) {
return false
}
return len(aps[i].Subjects) > len(aps[j].Subjects)
})

// remove any empty policies (except subjects, of course)
emptyAP := new(caddytls.AutomationPolicy)
for i := 0; i < len(aps); i++ {
for j := 0; j < len(aps); j++ {
if j == i {
continue
}
emptyAP.Subjects = aps[i].Subjects
if reflect.DeepEqual(aps[i], emptyAP) {
aps = append(aps[:i], aps[i+1:]...)
i--
}
}

// remove or combine duplicate policies
for i := 0; i < len(aps); i++ {
for j := i + 1; j < len(aps); j++ {
// if they're exactly equal in every way, just keep one of them
if reflect.DeepEqual(aps[i], aps[j]) {
aps = append(aps[:j], aps[j+1:]...)
Expand All @@ -473,10 +469,17 @@ func consolidateAutomationPolicies(aps []*caddytls.AutomationPolicy) []*caddytls
aps[i].KeyType == aps[j].KeyType &&
aps[i].OnDemand == aps[j].OnDemand &&
aps[i].RenewalWindowRatio == aps[j].RenewalWindowRatio {
if len(aps[i].Subjects) == 0 && len(aps[j].Subjects) > 0 {
aps = append(aps[:j], aps[j+1:]...)
} else if len(aps[i].Subjects) > 0 && len(aps[j].Subjects) == 0 {
aps = append(aps[:i], aps[i+1:]...)
if len(aps[i].Subjects) > 0 && len(aps[j].Subjects) == 0 {
// later policy (at j) has no subjects ("catch-all"), so we can
// remove the identical-but-more-specific policy that comes first
// AS LONG AS it is not shadowed by another policy before it; e.g.
// if policy i is for example.com, policy i+1 is '*.com', and policy
// j is catch-all, we cannot remove policy i because that would
// cause example.com to be served by the less specific policy for
// '*.com', which might be different (yes we've seen this happen)
if automationPolicyShadows(i, aps) >= j {
aps = append(aps[:i], aps[i+1:]...)
}
} else {
// avoid repeated subjects
for _, subj := range aps[j].Subjects {
Expand All @@ -486,16 +489,48 @@ func consolidateAutomationPolicies(aps []*caddytls.AutomationPolicy) []*caddytls
}
aps = append(aps[:j], aps[j+1:]...)
}
i--
break
}
}
}

// ensure any catch-all policies go last
sort.SliceStable(aps, func(i, j int) bool {
return len(aps[i].Subjects) > len(aps[j].Subjects)
})

return aps
}

// automationPolicyIsSubset returns true if a's subjects are a subset
// of b's subjects.
func automationPolicyIsSubset(a, b *caddytls.AutomationPolicy) bool {
if len(b.Subjects) == 0 {
return true
}
if len(a.Subjects) == 0 {
return false
}
for _, aSubj := range a.Subjects {
var inSuperset bool
for _, bSubj := range b.Subjects {
if certmagic.MatchWildcard(aSubj, bSubj) {
inSuperset = true
break
}
}
if !inSuperset {
return false
}
}
return true
}

// automationPolicyShadows returns the index of a policy that aps[i] shadows;
// in other words, for all policies after position i, if that policy covers
// the same subjects but is less specific, that policy's position is returned,
// or -1 if no shadowing is found. For example, if policy i is for
// "foo.example.com" and policy i+2 is for "*.example.com", then i+2 will be
// returned, since that policy is shadowed by i, which is in front.
func automationPolicyShadows(i int, aps []*caddytls.AutomationPolicy) int {
for j := i + 1; j < len(aps); j++ {
if automationPolicyIsSubset(aps[i], aps[j]) {
return j
}
}
return -1
}
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