13813778123

Committed 12 Mar 2025 02:24PM UTC coverage: 68.65% (+0.003%) from 68.647%

Build # 13813778123

Build Type

Pull #9546

github

Committed by

web-flow

Commit Message

Merge dca2eb21c into 6531d4505

Pull Request Pull Request #9546: macaroons: ip range constraint

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75.86

/macaroons/constraints.go

package macaroons

import (
        "bytes"
        "context"
        "fmt"
        "net"
        "strings"
        "time"

        "google.golang.org/grpc/peer"
        "gopkg.in/macaroon-bakery.v2/bakery/checkers"
        macaroon "gopkg.in/macaroon.v2"
)

const (
        // CondLndCustom is the first party caveat condition name that is used
        // for all custom caveats in lnd. Every custom caveat entry will be
        // encoded as the string
        // "lnd-custom <custom-caveat-name> <custom-caveat-condition>"
        // in the serialized macaroon. We choose a single space as the delimiter
        // between the because that is also used by the macaroon bakery library.
        CondLndCustom = "lnd-custom"

        // CondIpRange is the caveat condition name that is used for tying an IP
        // range to a macaroon.
        CondIpRange = "iprange"
)

// CustomCaveatAcceptor is an interface that contains a single method for
// checking whether a macaroon with the given custom caveat name should be
// accepted or not.
type CustomCaveatAcceptor interface {
        // CustomCaveatSupported returns nil if a macaroon with the given custom
        // caveat name can be validated by any component in lnd (for example an
        // RPC middleware). If no component is registered to handle the given
        // custom caveat then an error must be returned. This method only checks
        // the availability of a validating component, not the validity of the
        // macaroon itself.
        CustomCaveatSupported(customCaveatName string) error
}

// Constraint type adds a layer of indirection over macaroon caveats.
type Constraint func(*macaroon.Macaroon) error

// Checker type adds a layer of indirection over macaroon checkers. A Checker
// returns the name of the checker and the checker function; these are used to
// register the function with the bakery service's compound checker.
type Checker func() (string, checkers.Func)

// AddConstraints returns new derived macaroon by applying every passed
// constraint and tightening its restrictions.
func AddConstraints(mac *macaroon.Macaroon,
        cs ...Constraint) (*macaroon.Macaroon, error) {

        // The macaroon library's Clone() method has a subtle bug that doesn't
        // correctly clone all caveats. We need to use our own, safe clone
        // function instead.
        newMac, err := SafeCopyMacaroon(mac)
        if err != nil {
                return nil, err
        }

        for _, constraint := range cs {
                if err := constraint(newMac); err != nil {
                        return nil, err
                }
        }
        return newMac, nil
}

// Each *Constraint function is a functional option, which takes a pointer
// to the macaroon and adds another restriction to it. For each *Constraint,
// the corresponding *Checker is provided if not provided by default.

// TimeoutConstraint restricts the lifetime of the macaroon
// to the amount of seconds given.
func TimeoutConstraint(seconds int64) func(*macaroon.Macaroon) error {
        return func(mac *macaroon.Macaroon) error {
                macaroonTimeout := time.Duration(seconds)
                requestTimeout := time.Now().Add(time.Second * macaroonTimeout)
                caveat := checkers.TimeBeforeCaveat(requestTimeout)
                return mac.AddFirstPartyCaveat([]byte(caveat.Condition))
        }
}

// IPLockConstraint locks a macaroon to a specific IP address. If ipAddr is an
// empty string, this constraint does nothing to accommodate  default value's
// desired behavior.
func IPLockConstraint(ipAddr string) func(*macaroon.Macaroon) error {
        return func(mac *macaroon.Macaroon) error {
                if ipAddr != "" {
                        macaroonIPAddr := net.ParseIP(ipAddr)
                        if macaroonIPAddr == nil {
                                return fmt.Errorf("incorrect macaroon IP-" +
                                        "lock address")
                        }
                        caveat := checkers.Condition("ipaddr",
                                macaroonIPAddr.String())

                        return mac.AddFirstPartyCaveat([]byte(caveat))
                }

                return nil
        }
}

// IPRangeLockConstraint locks a macaroon to a specific IP address range. If
// ipRange is an empty string, this constraint does nothing to accommodate
// default value's desired behavior.
func IPRangeLockConstraint(ipRange string) func(*macaroon.Macaroon) error {
        return func(mac *macaroon.Macaroon) error {
                if ipRange != "" {
                        _, parsedNet, err := net.ParseCIDR(ipRange)
                        if err != nil {
                                return fmt.Errorf("incorrect macaroon IP "+
                                        "range: %w", err)
                        }
                        caveat := checkers.Condition(
                                CondIpRange, parsedNet.String(),
                        )

                        return mac.AddFirstPartyCaveat([]byte(caveat))
                }

                return nil
        }
}

// IPLockChecker accepts client IP from the validation context and compares it
// with IP locked in the macaroon. It is of the `Checker` type.
func IPLockChecker() (string, checkers.Func) {
        return "ipaddr", func(ctx context.Context, cond, arg string) error {
                // Get peer info and extract IP address from it for macaroon
                // check.
                pr, ok := peer.FromContext(ctx)
                if !ok {
                        return fmt.Errorf("unable to get peer info from context")
                }
                peerAddr, _, err := net.SplitHostPort(pr.Addr.String())
                if err != nil {
                        return fmt.Errorf("unable to parse peer address")
                }

                if !net.ParseIP(arg).Equal(net.ParseIP(peerAddr)) {
                        msg := "macaroon locked to different IP address"
                        return fmt.Errorf(msg)
                }
                return nil
        }
}

// IPRangeLockChecker accepts client IP range from the validation context and
// compares it with the IP range locked in the macaroon. It is of the `Checker`
// type.
func IPRangeLockChecker() (string, checkers.Func) {
        return CondIpRange, func(ctx context.Context, cond, arg string) error {
                // Get peer info and extract IP range from it for macaroon
                // check.
                pr, ok := peer.FromContext(ctx)
                if !ok {
                        return fmt.Errorf("unable to get peer info from " +
                                "context")
                }
                peerAddr, _, err := net.SplitHostPort(pr.Addr.String())
                if err != nil {
                        return fmt.Errorf("unable to parse peer address: %w",
                                err)
                }

                _, ipNet, err := net.ParseCIDR(arg)
                if err != nil {
                        return fmt.Errorf("unable to parse macaroon IP "+
                                "range: %w", err)
                }

                if !ipNet.Contains(net.ParseIP(peerAddr)) {
                        msg := "macaroon locked to different IP range"
                        return fmt.Errorf(msg)
                }

                return nil
        }
}

// CustomConstraint returns a function that adds a custom caveat condition to
// a macaroon.
func CustomConstraint(name, condition string) func(*macaroon.Macaroon) error {
        return func(mac *macaroon.Macaroon) error {
                // We rely on a name being set for the interception, so don't
                // allow creating a caveat without a name in the first place.
                if name == "" {
                        return fmt.Errorf("name cannot be empty")
                }

                // The inner (custom) condition is optional.
                outerCondition := fmt.Sprintf("%s %s", name, condition)
                if condition == "" {
                        outerCondition = name
                }

                caveat := checkers.Condition(CondLndCustom, outerCondition)
                return mac.AddFirstPartyCaveat([]byte(caveat))
        }
}

// CustomChecker returns a Checker function that is used by the macaroon bakery
// library to check whether a custom caveat is supported by lnd in general or
// not. Support in this context means: An additional gRPC interceptor was set up
// that validates the content (=condition) of the custom caveat. If such an
// interceptor is in place then the acceptor should return a nil error. If no
// interceptor exists for the custom caveat in the macaroon of a request context
// then a non-nil error should be returned and the macaroon is rejected as a
// whole.
func CustomChecker(acceptor CustomCaveatAcceptor) Checker {
        // We return the general name of all lnd custom macaroons and a function
        // that splits the outer condition to extract the name of the custom
        // condition and the condition itself. In the bakery library that's used
        // here, a caveat always has the following form:
        //
        // <condition-name> <condition-value>
        //
        // Because a checker function needs to be bound to the condition name we
        // have to choose a static name for the first part ("lnd-custom", see
        // CondLndCustom. Otherwise we'd need to register a new Checker function
        // for each custom caveat that's registered. To allow for a generic
        // custom caveat handling, we just add another layer and expand the
        // initial <condition-value> into
        //
        // "<custom-condition-name> <custom-condition-value>"
        //
        // The full caveat string entry of a macaroon that uses this generic
        // mechanism would therefore look like this:
        //
        // "lnd-custom <custom-condition-name> <custom-condition-value>"
        checker := func(_ context.Context, _, outerCondition string) error {
                if outerCondition != strings.TrimSpace(outerCondition) {
                        return fmt.Errorf("unexpected white space found in " +
                                "caveat condition")
                }
                if outerCondition == "" {
                        return fmt.Errorf("expected custom caveat, got empty " +
                                "string")
                }

                // The condition part of the original caveat is now name and
                // condition of the custom caveat (we add a layer of conditions
                // to allow one custom checker to work for all custom lnd
                // conditions that implement arbitrary business logic).
                parts := strings.Split(outerCondition, " ")
                customCaveatName := parts[0]

                return acceptor.CustomCaveatSupported(customCaveatName)
        }

        return func() (string, checkers.Func) {
                return CondLndCustom, checker
        }
}

// HasCustomCaveat tests if the given macaroon has a custom caveat with the
// given custom caveat name.
func HasCustomCaveat(mac *macaroon.Macaroon, customCaveatName string) bool {
        if mac == nil {
                return false
        }

        caveatPrefix := []byte(fmt.Sprintf(
                "%s %s", CondLndCustom, customCaveatName,
        ))
        for _, caveat := range mac.Caveats() {
                if bytes.HasPrefix(caveat.Id, caveatPrefix) {
                        return true
                }
        }

        return false
}

// GetCustomCaveatCondition returns the custom caveat condition for the given
// custom caveat name from the given macaroon.
func GetCustomCaveatCondition(mac *macaroon.Macaroon,
        customCaveatName string) string {

        if mac == nil {
                return ""
        }

        caveatPrefix := []byte(fmt.Sprintf(
                "%s %s ", CondLndCustom, customCaveatName,
        ))
        for _, caveat := range mac.Caveats() {
                // The caveat id has a format of
                // "lnd-custom [custom-caveat-name] [custom-caveat-condition]"
                // and we only want the condition part. If we match the prefix
                // part we return the condition that comes after the prefix.
                if bytes.HasPrefix(caveat.Id, caveatPrefix) {
                        caveatSplit := strings.SplitN(
                                string(caveat.Id),
                                string(caveatPrefix),
                                2,
                        )
                        if len(caveatSplit) == 2 {
                                return caveatSplit[1]
                        }
                }
        }

        // We didn't find a condition for the given custom caveat name.
        return ""
}

1	package macaroons
2
3	import (
4	"bytes"
5	"context"
6	"fmt"
7	"net"
8	"strings"
9	"time"
10
11	"google.golang.org/grpc/peer"
12	"gopkg.in/macaroon-bakery.v2/bakery/checkers"
13	macaroon "gopkg.in/macaroon.v2"
14	)
15
16	const (
17	// CondLndCustom is the first party caveat condition name that is used
18	// for all custom caveats in lnd. Every custom caveat entry will be
19	// encoded as the string
20	// "lnd-custom <custom-caveat-name> <custom-caveat-condition>"
21	// in the serialized macaroon. We choose a single space as the delimiter
22	// between the because that is also used by the macaroon bakery library.
23	CondLndCustom = "lnd-custom"
24
25	// CondIpRange is the caveat condition name that is used for tying an IP
26	// range to a macaroon.
27	CondIpRange = "iprange"
28	)
29
30	// CustomCaveatAcceptor is an interface that contains a single method for
31	// checking whether a macaroon with the given custom caveat name should be
32	// accepted or not.
33	type CustomCaveatAcceptor interface {
34	// CustomCaveatSupported returns nil if a macaroon with the given custom
35	// caveat name can be validated by any component in lnd (for example an
36	// RPC middleware). If no component is registered to handle the given
37	// custom caveat then an error must be returned. This method only checks
38	// the availability of a validating component, not the validity of the
39	// macaroon itself.
40	CustomCaveatSupported(customCaveatName string) error
41	}
42
43	// Constraint type adds a layer of indirection over macaroon caveats.
44	type Constraint func(*macaroon.Macaroon) error
45
46	// Checker type adds a layer of indirection over macaroon checkers. A Checker
47	// returns the name of the checker and the checker function; these are used to
48	// register the function with the bakery service's compound checker.
49	type Checker func() (string, checkers.Func)
50
51	// AddConstraints returns new derived macaroon by applying every passed
52	// constraint and tightening its restrictions.
53	func AddConstraints(mac *macaroon.Macaroon,
54	cs ...Constraint) (*macaroon.Macaroon, error) {	1✔
55		1✔
56	// The macaroon library's Clone() method has a subtle bug that doesn't	1✔
57	// correctly clone all caveats. We need to use our own, safe clone	1✔
58	// function instead.	1✔
59	newMac, err := SafeCopyMacaroon(mac)	1✔
60	if err != nil {	1✔
61	return nil, err	×
62	}	×
63
64	for _, constraint := range cs {	2✔
65	if err := constraint(newMac); err != nil {	1✔
66	return nil, err	×
67	}	×
68	}
69	return newMac, nil	1✔
70	}
71
72	// Each *Constraint function is a functional option, which takes a pointer
73	// to the macaroon and adds another restriction to it. For each *Constraint,
74	// the corresponding *Checker is provided if not provided by default.
75
76	// TimeoutConstraint restricts the lifetime of the macaroon
77	// to the amount of seconds given.
78	func TimeoutConstraint(seconds int64) func(*macaroon.Macaroon) error {	3✔
79	return func(mac *macaroon.Macaroon) error {	6✔
80	macaroonTimeout := time.Duration(seconds)	3✔
81	requestTimeout := time.Now().Add(time.Second * macaroonTimeout)	3✔
82	caveat := checkers.TimeBeforeCaveat(requestTimeout)	3✔
83	return mac.AddFirstPartyCaveat([]byte(caveat.Condition))	3✔
84	}	3✔
85	}
86
87	// IPLockConstraint locks a macaroon to a specific IP address. If ipAddr is an
88	// empty string, this constraint does nothing to accommodate default value's
89	// desired behavior.
90	func IPLockConstraint(ipAddr string) func(*macaroon.Macaroon) error {	2✔
91	return func(mac *macaroon.Macaroon) error {	4✔
92	if ipAddr != "" {	4✔
93	macaroonIPAddr := net.ParseIP(ipAddr)	2✔
94	if macaroonIPAddr == nil {	3✔
95	return fmt.Errorf("incorrect macaroon IP-" +	1✔
96	"lock address")	1✔
97	}	1✔
98	caveat := checkers.Condition("ipaddr",	1✔
99	macaroonIPAddr.String())	1✔
100		1✔
101	return mac.AddFirstPartyCaveat([]byte(caveat))	1✔
102	}
103
NEW 104	return nil	×
105	}
106	}
107
108	// IPRangeLockConstraint locks a macaroon to a specific IP address range. If
109	// ipRange is an empty string, this constraint does nothing to accommodate
110	// default value's desired behavior.
NEW 111	func IPRangeLockConstraint(ipRange string) func(*macaroon.Macaroon) error {	×
NEW 112	return func(mac *macaroon.Macaroon) error {	×
NEW 113	if ipRange != "" {	×
NEW 114	_, parsedNet, err := net.ParseCIDR(ipRange)	×
NEW 115	if err != nil {	×
NEW 116	return fmt.Errorf("incorrect macaroon IP "+	×
NEW 117	"range: %w", err)	×
NEW 118	}	×
NEW 119	caveat := checkers.Condition(	×
NEW 120	CondIpRange, parsedNet.String(),	×
NEW 121	)	×
NEW 122		×
UNCOV 123	return mac.AddFirstPartyCaveat([]byte(caveat))	×
124	}
125
UNCOV 126	return nil	×
127	}
128	}
129
130	// IPLockChecker accepts client IP from the validation context and compares it
131	// with IP locked in the macaroon. It is of the `Checker` type.
132	func IPLockChecker() (string, checkers.Func) {	8✔
133	return "ipaddr", func(ctx context.Context, cond, arg string) error {	11✔
134	// Get peer info and extract IP address from it for macaroon	3✔
135	// check.	3✔
136	pr, ok := peer.FromContext(ctx)	3✔
137	if !ok {	3✔
138	return fmt.Errorf("unable to get peer info from context")	×
139	}	×
140	peerAddr, _, err := net.SplitHostPort(pr.Addr.String())	3✔
141	if err != nil {	3✔
142	return fmt.Errorf("unable to parse peer address")	×
143	}	×
144
145	if !net.ParseIP(arg).Equal(net.ParseIP(peerAddr)) {	6✔
146	msg := "macaroon locked to different IP address"	3✔
147	return fmt.Errorf(msg)	3✔
148	}	3✔
149	return nil	3✔
150	}
151	}
152
153	// IPRangeLockChecker accepts client IP range from the validation context and
154	// compares it with the IP range locked in the macaroon. It is of the `Checker`
155	// type.
156	func IPRangeLockChecker() (string, checkers.Func) {	3✔
157	return CondIpRange, func(ctx context.Context, cond, arg string) error {	6✔
158	// Get peer info and extract IP range from it for macaroon	3✔
159	// check.	3✔
160	pr, ok := peer.FromContext(ctx)	3✔
161	if !ok {	3✔
NEW 162	return fmt.Errorf("unable to get peer info from " +	×
NEW 163	"context")	×
NEW 164	}	×
165	peerAddr, _, err := net.SplitHostPort(pr.Addr.String())	3✔
166	if err != nil {	3✔
NEW 167	return fmt.Errorf("unable to parse peer address: %w",	×
NEW 168	err)	×
NEW 169	}	×
170
171	_, ipNet, err := net.ParseCIDR(arg)	3✔
172	if err != nil {	3✔
NEW 173	return fmt.Errorf("unable to parse macaroon IP "+	×
NEW 174	"range: %w", err)	×
NEW 175	}	×
176
177	if !ipNet.Contains(net.ParseIP(peerAddr)) {	6✔
178	msg := "macaroon locked to different IP range"	3✔
179	return fmt.Errorf(msg)	3✔
180	}	3✔
181
182	return nil	3✔
183	}
184	}
185
186	// CustomConstraint returns a function that adds a custom caveat condition to
187	// a macaroon.
188	func CustomConstraint(name, condition string) func(*macaroon.Macaroon) error {	2✔
189	return func(mac *macaroon.Macaroon) error {	4✔
190	// We rely on a name being set for the interception, so don't	2✔
191	// allow creating a caveat without a name in the first place.	2✔
192	if name == "" {	2✔
193	return fmt.Errorf("name cannot be empty")	×
194	}	×
195
196	// The inner (custom) condition is optional.
197	outerCondition := fmt.Sprintf("%s %s", name, condition)	2✔
198	if condition == "" {	3✔
199	outerCondition = name	1✔
200	}	1✔
201
202	caveat := checkers.Condition(CondLndCustom, outerCondition)	2✔
203	return mac.AddFirstPartyCaveat([]byte(caveat))	2✔
204	}
205	}
206
207	// CustomChecker returns a Checker function that is used by the macaroon bakery
208	// library to check whether a custom caveat is supported by lnd in general or
209	// not. Support in this context means: An additional gRPC interceptor was set up
210	// that validates the content (=condition) of the custom caveat. If such an
211	// interceptor is in place then the acceptor should return a nil error. If no
212	// interceptor exists for the custom caveat in the macaroon of a request context
213	// then a non-nil error should be returned and the macaroon is rejected as a
214	// whole.
215	func CustomChecker(acceptor CustomCaveatAcceptor) Checker {	3✔
216	// We return the general name of all lnd custom macaroons and a function	3✔
217	// that splits the outer condition to extract the name of the custom	3✔
218	// condition and the condition itself. In the bakery library that's used	3✔
219	// here, a caveat always has the following form:	3✔
220	//	3✔
221	// <condition-name> <condition-value>	3✔
222	//	3✔
223	// Because a checker function needs to be bound to the condition name we	3✔
224	// have to choose a static name for the first part ("lnd-custom", see	3✔
225	// CondLndCustom. Otherwise we'd need to register a new Checker function	3✔
226	// for each custom caveat that's registered. To allow for a generic	3✔
227	// custom caveat handling, we just add another layer and expand the	3✔
228	// initial <condition-value> into	3✔
229	//	3✔
230	// "<custom-condition-name> <custom-condition-value>"	3✔
231	//	3✔
232	// The full caveat string entry of a macaroon that uses this generic	3✔
233	// mechanism would therefore look like this:	3✔
234	//	3✔
235	// "lnd-custom <custom-condition-name> <custom-condition-value>"	3✔
236	checker := func(_ context.Context, _, outerCondition string) error {	6✔
237	if outerCondition != strings.TrimSpace(outerCondition) {	3✔
238	return fmt.Errorf("unexpected white space found in " +	×
239	"caveat condition")	×
240	}	×
241	if outerCondition == "" {	3✔
242	return fmt.Errorf("expected custom caveat, got empty " +	×
243	"string")	×
244	}	×
245
246	// The condition part of the original caveat is now name and
247	// condition of the custom caveat (we add a layer of conditions
248	// to allow one custom checker to work for all custom lnd
249	// conditions that implement arbitrary business logic).
250	parts := strings.Split(outerCondition, " ")	3✔
251	customCaveatName := parts[0]	3✔
252		3✔
253	return acceptor.CustomCaveatSupported(customCaveatName)	3✔
254	}
255
256	return func() (string, checkers.Func) {	6✔
257	return CondLndCustom, checker	3✔
258	}	3✔
259	}
260
261	// HasCustomCaveat tests if the given macaroon has a custom caveat with the
262	// given custom caveat name.
263	func HasCustomCaveat(mac *macaroon.Macaroon, customCaveatName string) bool {	10✔
264	if mac == nil {	11✔
265	return false	1✔
266	}	1✔
267
268	caveatPrefix := []byte(fmt.Sprintf(	9✔
269	"%s %s", CondLndCustom, customCaveatName,	9✔
270	))	9✔
271	for _, caveat := range mac.Caveats() {	18✔
272	if bytes.HasPrefix(caveat.Id, caveatPrefix) {	14✔
273	return true	5✔
274	}	5✔
275	}
276
277	return false	7✔
278	}
279
280	// GetCustomCaveatCondition returns the custom caveat condition for the given
281	// custom caveat name from the given macaroon.
282	func GetCustomCaveatCondition(mac *macaroon.Macaroon,
283	customCaveatName string) string {	5✔
284		5✔
285	if mac == nil {	5✔
286	return ""	×
287	}	×
288
289	caveatPrefix := []byte(fmt.Sprintf(	5✔
290	"%s %s ", CondLndCustom, customCaveatName,	5✔
291	))	5✔
292	for _, caveat := range mac.Caveats() {	10✔
293	// The caveat id has a format of	5✔
294	// "lnd-custom [custom-caveat-name] [custom-caveat-condition]"	5✔
295	// and we only want the condition part. If we match the prefix	5✔
296	// part we return the condition that comes after the prefix.	5✔
297	if bytes.HasPrefix(caveat.Id, caveatPrefix) {	9✔
298	caveatSplit := strings.SplitN(	4✔
299	string(caveat.Id),	4✔
300	string(caveatPrefix),	4✔
301	2,	4✔
302	)	4✔
303	if len(caveatSplit) == 2 {	8✔
304	return caveatSplit[1]	4✔
305	}	4✔
306	}
307	}
308
309	// We didn't find a condition for the given custom caveat name.
310	return ""	4✔
311	}

lightningnetwork / lnd / 13813778123

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