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package ubiquity
import (
"crypto/x509"
"fmt"
"time"
"github.com/cloudflare/cfssl/helpers"
)
// DeprecationSeverity encodes the severity of a deprecation policy
type DeprecationSeverity int
const (
// None indicates there is no deprecation
None DeprecationSeverity = iota
// Low indicates the deprecation policy won't affect user experience
Low
// Medium indicates the deprecation policy will affect user experience
// either in a minor way or for a limited scope of users.
Medium
// High indicates the deprecation policy will strongly affect user experience
High
)
// SHA1DeprecationPolicy encodes how a platform deprecates the support of SHA1
type SHA1DeprecationPolicy struct {
// the name of platform
Platform string `json:"platform"`
// policy severity, policies of the same platform will only trigger the one of highest severity
Severity DeprecationSeverity `json:"severity"`
// a human readable message describing the deprecation effects
Description string `json:"description"`
// the date when the policy is effective. zero value means effective immediately
EffectiveDate time.Time `json:"effective_date"`
// the expiry deadline indicates the latest date which a end-entity
// certificate with SHA1 can be valid through.
ExpiryDeadline time.Time `json:"expiry_deadline"`
// the date beyond which SHA1 cert should not be issued.
NeverIssueAfter time.Time `json:"never_issue_after"`
}
// SHA1DeprecationPolicys ia a list of various SHA1DeprecationPolicy's
// proposed by major browser producers
var SHA1DeprecationPolicys = []SHA1DeprecationPolicy{
// Chrome:
// if the leaf certificate expires between 01-01-2016 and 01-01-2017
// and the chain (excluding root) contains SHA-1 cert, show "minor errors".
{
Platform: "Google Chrome",
Description: "shows the SSL connection has minor problems",
Severity: Medium,
ExpiryDeadline: time.Date(2016, time.January, 1, 0, 0, 0, 0, time.UTC),
},
// Chrome:
// if the leaf certificate expires after Jan. 1st 2017
// and the chain (excluding root) contains SHA-1 cert, show "untrusted SSL".
{
Platform: "Google Chrome",
Description: "shows the SSL connection is untrusted",
Severity: High,
ExpiryDeadline: time.Date(2017, time.January, 1, 0, 0, 0, 0, time.UTC),
},
// Mozilla Firefox:
// if the leaf certificate expires after Jan. 1st 2017, and
// the chain (excluding root) contains SHA-1 cert, show a warning in the developer console.
{
Platform: "Mozilla Firefox",
Description: "gives warning in the developer console",
Severity: Low,
ExpiryDeadline: time.Date(2017, time.January, 1, 0, 0, 0, 0, time.UTC),
},
// Mozilla Firefox:
// if a new certificate is issued after Jan. 1st 2016, and
// it is a SHA-1 cert, reject it.
{
Platform: "Mozilla Firefox",
Description: "shows the SSL connection is untrusted",
Severity: Medium,
EffectiveDate: time.Date(2016, time.January, 1, 0, 0, 0, 0, time.UTC),
NeverIssueAfter: time.Date(2016, time.January, 1, 0, 0, 0, 0, time.UTC),
},
// Mozilla Firefox:
// deprecate all valid SHA-1 cert chain on Jan. 1st 2017
{
Platform: "Mozilla Firefox",
Description: "shows the SSL connection is untrusted",
Severity: High,
EffectiveDate: time.Date(2017, time.January, 1, 0, 0, 0, 0, time.UTC),
ExpiryDeadline: time.Date(2017, time.January, 1, 0, 0, 0, 0, time.UTC),
},
// Microsoft Windows:
// deprecate all valid SHA-1 cert chain on Jan. 1st 2017
{
Platform: "Microsoft Windows Vista and later",
Description: "shows the SSL connection is untrusted",
Severity: High,
EffectiveDate: time.Date(2017, time.January, 1, 0, 0, 0, 0, time.UTC),
ExpiryDeadline: time.Date(2017, time.January, 1, 0, 0, 0, 0, time.UTC),
},
}
// Flag returns whether the policy flags the cert chain as deprecated for matching its deprecation criteria
func (p SHA1DeprecationPolicy) Flag(chain []*x509.Certificate) bool {
leaf := chain[0]
if time.Now().After(p.EffectiveDate) {
// Reject newly issued leaf certificate with SHA-1 after the specified deadline.
if !p.NeverIssueAfter.IsZero() && leaf.NotBefore.After(p.NeverIssueAfter) {
// Check hash algorithm of non-root leaf cert.
if len(chain) > 1 && helpers.HashAlgoString(leaf.SignatureAlgorithm) == "SHA1" {
return true
}
}
// Reject certificate chain with SHA-1 that are still valid after expiry deadline.
if !p.ExpiryDeadline.IsZero() && leaf.NotAfter.After(p.ExpiryDeadline) {
// Check hash algorithm of non-root certs.
for i, cert := range chain {
if i < len(chain)-1 {
if helpers.HashAlgoString(cert.SignatureAlgorithm) == "SHA1" {
return true
}
}
}
}
}
return false
}
// SHA1DeprecationMessages returns a list of human-readable messages. Each message describes
// how one platform rejects the chain based on SHA1 deprecation policies.
func SHA1DeprecationMessages(chain []*x509.Certificate) []string {
// record the most severe deprecation policy by each platform
selectedPolicies := map[string]SHA1DeprecationPolicy{}
for _, policy := range SHA1DeprecationPolicys {
if policy.Flag(chain) {
// only keep the policy with highest severity
if selectedPolicies[policy.Platform].Severity < policy.Severity {
selectedPolicies[policy.Platform] = policy
}
}
}
// build the message list
list := []string{}
for _, policy := range selectedPolicies {
if policy.Severity > None {
list = append(list, fmt.Sprintf("%s %s due to SHA-1 deprecation", policy.Platform, policy.Description))
}
}
return list
}
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