CSS-5672 Adds declared caveats to the discharge macaroon. #1047
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| Original file line number | Diff line number | Diff line change |
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| @@ -0,0 +1,159 @@ | ||
| // Copyright 2023 Canonical Ltd. | ||
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| package jimm | ||
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| import ( | ||
| "context" | ||
| "net/http" | ||
| "strings" | ||
| "time" | ||
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| "github.com/go-macaroon-bakery/macaroon-bakery/v3/bakery" | ||
| "github.com/go-macaroon-bakery/macaroon-bakery/v3/bakery/checkers" | ||
| "github.com/go-macaroon-bakery/macaroon-bakery/v3/bakery/dbrootkeystore" | ||
| "github.com/go-macaroon-bakery/macaroon-bakery/v3/httpbakery" | ||
| jjmacaroon "github.com/juju/juju/core/macaroon" | ||
| "github.com/juju/names/v4" | ||
| "github.com/juju/zaputil/zapctx" | ||
| "go.uber.org/zap" | ||
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| "github.com/canonical/jimm/internal/db" | ||
| "github.com/canonical/jimm/internal/dbmodel" | ||
| "github.com/canonical/jimm/internal/errors" | ||
| "github.com/canonical/jimm/internal/openfga" | ||
| ofganames "github.com/canonical/jimm/internal/openfga/names" | ||
| jimmnames "github.com/canonical/jimm/pkg/names" | ||
| ) | ||
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| var defaultDischargeExpiry = 15 * time.Minute | ||
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| func newMacaroonDischarger(p Params, db *db.Database, ofgaClient *openfga.OFGAClient) (*macaroonDischarger, error) { | ||
| var kp bakery.KeyPair | ||
| if p.PublicKey == "" || p.PrivateKey == "" { | ||
| generatedKP, err := bakery.GenerateKey() | ||
| if err != nil { | ||
| return nil, errors.E(err, "failed to generate a bakery keypair") | ||
| } | ||
| kp = *generatedKP | ||
| } else { | ||
| if err := kp.Private.UnmarshalText([]byte(p.PrivateKey)); err != nil { | ||
| return nil, errors.E(err, "cannot unmarshal private key") | ||
| } | ||
| if err := kp.Public.UnmarshalText([]byte(p.PublicKey)); err != nil { | ||
| return nil, errors.E(err, "cannot unmarshal public key") | ||
| } | ||
| } | ||
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| checker := checkers.New(jjmacaroon.MacaroonNamespace) | ||
| b := bakery.New( | ||
| bakery.BakeryParams{ | ||
| Checker: checker, | ||
| RootKeyStore: dbrootkeystore.NewRootKeys(100, nil).NewStore( | ||
| db, | ||
| dbrootkeystore.Policy{ | ||
| ExpiryDuration: p.MacaroonExpiryDuration, | ||
| }, | ||
| ), | ||
| Key: &kp, | ||
| Location: "jimm " + p.ControllerUUID, | ||
| }, | ||
| ) | ||
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| return &macaroonDischarger{ | ||
| ofgaClient: ofgaClient, | ||
| bakery: b, | ||
| kp: kp, | ||
| }, nil | ||
| } | ||
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| type macaroonDischarger struct { | ||
| ofgaClient *openfga.OFGAClient | ||
| bakery *bakery.Bakery | ||
| kp bakery.KeyPair | ||
| } | ||
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| // thirdPartyCaveatCheckerFunction returns a function that | ||
| // checks third party caveats addressed to this service. | ||
| // Caveat format is: | ||
| // | ||
| // is-<relation name> <user tag> <resource tag> | ||
| // | ||
| // Examples of caveats are: | ||
| // | ||
| // is-reader <user tag> <offer tag containing uuid> | ||
| // is-consumer <user tag> <offer tag containing uuid> | ||
| // is-administrator <user tag> <offer tag containing uuid> | ||
| // is-reader <user tag> <model tag containing uuid> | ||
| // is-writer <user tag> <model tag containing uuid> | ||
| // is-admininistrator <user tag> <model tag containing uuid> | ||
| // is-admininistrator <user tag> <controller tag containing uuid> | ||
| // | ||
| // The discharged macaroon will contain a time-before first party caveat and | ||
| // a declared caveat declaring relation to the required entity in form of: | ||
| // | ||
| // <relation> <entity tag> | ||
| // | ||
| // Example: | ||
| // 1. if the third party caveat condition is: | ||
| // is-reader <user tag> <offer tag containing uuid> | ||
| // the declared caveat will contain | ||
| // reader <offer tag> | ||
| // 2. if the third party caveat condition is: | ||
| // is-writer <user tag> <model tag containing uuid> | ||
| // the declared caveat will contain | ||
| // writer <model tag> | ||
| func (md *macaroonDischarger) checkThirdPartyCaveat(ctx context.Context, req *http.Request, cavInfo *bakery.ThirdPartyCaveatInfo, _ *httpbakery.DischargeToken) ([]checkers.Caveat, error) { | ||
| caveatTokens := strings.Split(string(cavInfo.Condition), " ") | ||
| if len(caveatTokens) != 3 { | ||
| zapctx.Error(ctx, "caveat token length incorrect", zap.Int("length", len(caveatTokens))) | ||
| return nil, checkers.ErrCaveatNotRecognized | ||
| } | ||
| relationString := caveatTokens[0] | ||
| userTagString := caveatTokens[1] | ||
| objectTagString := caveatTokens[2] | ||
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| if !strings.HasPrefix(relationString, "is-") { | ||
| zapctx.Error(ctx, "caveat token relation string missing prefix") | ||
| return nil, checkers.ErrCaveatNotRecognized | ||
| } | ||
| relationString = strings.TrimPrefix(relationString, "is-") | ||
| relation, err := ofganames.ParseRelation(relationString) | ||
| if err != nil { | ||
| zapctx.Error(ctx, "caveat token relation invalid", zap.Error(err)) | ||
| return nil, checkers.ErrCaveatNotRecognized | ||
| } | ||
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| userTag, err := names.ParseUserTag(userTagString) | ||
| if err != nil { | ||
| zapctx.Error(ctx, "failed to parse caveat user tag", zap.Error(err)) | ||
| return nil, checkers.ErrCaveatNotRecognized | ||
| } | ||
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| objectTag, err := jimmnames.ParseTag(objectTagString) | ||
| if err != nil { | ||
| zapctx.Error(ctx, "failed to parse caveat object tag", zap.Error(err)) | ||
| return nil, checkers.ErrCaveatNotRecognized | ||
| } | ||
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| user := openfga.NewUser( | ||
| &dbmodel.User{ | ||
| Username: userTag.Id(), | ||
| }, | ||
| md.ofgaClient, | ||
| ) | ||
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| allowed, err := openfga.CheckRelation(ctx, user, objectTag, relation) | ||
| if err != nil { | ||
| zapctx.Error(ctx, "failed to check request caveat relation", zap.Error(err)) | ||
| return nil, errors.E(err) | ||
| } | ||
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| if allowed { | ||
| return []checkers.Caveat{ | ||
| checkers.DeclaredCaveat(relationString, objectTagString), | ||
|
There was a problem hiding this comment. This is the main bit that changed right? |
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| checkers.TimeBeforeCaveat(time.Now().Add(defaultDischargeExpiry)), | ||
| }, nil | ||
| } | ||
| zapctx.Debug(ctx, "macaroon dishcharge denied", zap.String("user", user.Username), zap.String("object", objectTag.Id())) | ||
| return nil, httpbakery.ErrPermissionDenied | ||
| } | ||
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Much better having these functions moved out