Files
attest/mapping/match.go
2024-10-18 09:25:31 -05:00

97 lines
2.8 KiB
Go

/*
Copyright Docker attest authors
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
package mapping
import (
"fmt"
v1 "github.com/google/go-containerregistry/pkg/v1"
)
type matchType string
const (
MatchTypePolicy matchType = "policy"
MatchTypeMatchNoPolicy matchType = "match_no_policy"
MatchTypeNoMatch matchType = "no_match"
)
type PolicyMatch struct {
MatchType matchType
Policy *PolicyMapping
Rule *PolicyRule
MatchedName string
}
func (mappings *PolicyMappings) FindPolicyMatch(imageName string, platform *v1.Platform) (*PolicyMatch, error) {
if mappings == nil {
return &PolicyMatch{MatchType: MatchTypeNoMatch, MatchedName: imageName}, nil
}
return mappings.findPolicyMatchImpl(imageName, platform, make(map[*PolicyRule]bool))
}
func (mappings *PolicyMappings) findPolicyMatchImpl(imageName string, platform *v1.Platform, matched map[*PolicyRule]bool) (*PolicyMatch, error) {
for _, rule := range mappings.Rules {
if !rule.matchesPlatform(platform) {
continue
}
if rule.Pattern.MatchString(imageName) {
switch {
case rule.PolicyID == "" && rule.Replacement == "":
return nil, fmt.Errorf("rule %s has neither policy-id nor rewrite", rule.Pattern)
case rule.PolicyID != "" && rule.Replacement != "":
return nil, fmt.Errorf("rule %s has both policy-id and rewrite", rule.Pattern)
case rule.PolicyID != "":
policy := mappings.Policies[rule.PolicyID]
if policy != nil {
return &PolicyMatch{
MatchType: MatchTypePolicy,
Policy: policy,
Rule: rule,
MatchedName: imageName,
}, nil
}
return &PolicyMatch{
MatchType: MatchTypeMatchNoPolicy,
Rule: rule,
MatchedName: imageName,
}, nil
case rule.Replacement != "":
if matched[rule] {
return nil, fmt.Errorf("rewrite loop detected")
}
matched[rule] = true
imageName = rule.Pattern.ReplaceAllString(imageName, rule.Replacement)
return mappings.findPolicyMatchImpl(imageName, platform, matched)
}
}
}
return &PolicyMatch{MatchType: MatchTypeNoMatch}, nil
}
func (rule *PolicyRule) matchesPlatform(platform *v1.Platform) bool {
if len(rule.Platforms) == 0 {
return true
}
for i := range rule.Platforms {
if rule.Platforms[i].Equals(*platform) {
return true
}
}
return false
}