9 files changed, 530 insertions, 0 deletions
diff --git a/pkg/client/api/api.go b/pkg/client/api/api.go
new file mode 100644
index 0000000..d773bcc
--- /dev/null
+++ b/pkg/client/api/api.go
@@ -0,0 +1,22 @@
+// package api implements the Sigsum v0 API.  See
+//
+//     https://git.sigsum.org/sigsum/tree/doc/api.md
+//
+// for further details.  No verification, retries, etc., is done here.
+package api
+
+import (
+	"git.sigsum.org/sigsum-lib-go/pkg/requests"
+	"git.sigsum.org/sigsum-lib-go/pkg/types"
+)
+
+type API interface {
+	GetToCosignTreeHead() (*types.SignedTreeHead, error)
+	GetCosignedTreeHead() (*types.CosignedTreeHead, error)
+	GetInclusionProof(treeSize uint64, leafHash *types.Hash) (*types.InclusionProof, error)
+	GetConsistencyProof(oldSize, newSize uint64) (*types.ConsistencyProof, error)
+	GetLeaves(startSize, endSize uint64) (*types.Leaves, error)
+
+	AddLeaf(*requests.Leaf) error
+	AddCosignature(*requests.Cosignature) error
+}
diff --git a/pkg/client/api/network_client.go b/pkg/client/api/network_client.go
new file mode 100644
index 0000000..f7baf76
--- /dev/null
+++ b/pkg/client/api/network_client.go
@@ -0,0 +1,133 @@
+package api
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"log"
+	"net/http"
+
+	"git.sigsum.org/sigsum-lib-go/pkg/requests"
+	"git.sigsum.org/sigsum-lib-go/pkg/types"
+)
+
+type NetworkClient struct {
+	http.Client
+	LogURL string
+}
+
+func NewNetworkClient(httpClient http.Client, logURL string) *NetworkClient {
+	return &NetworkClient{
+		Client: httpClient,
+		LogURL: logURL,
+	}
+}
+
+func (c *NetworkClient) GetToCosignTreeHead() (*types.SignedTreeHead, error) {
+	return nil, fmt.Errorf("TODO")
+}
+
+func (c *NetworkClient) GetCosignedTreeHead() (*types.CosignedTreeHead, error) {
+	rsp, err := c.get(types.EndpointGetTreeHeadCosigned.Path(c.LogURL))
+	if err != nil {
+		return nil, fmt.Errorf("client: HTTP %d: %s", rsp.StatusCode, errorMessage(rsp.Body))
+	}
+
+	defer rsp.Body.Close()
+	if rsp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("client: HTTP %d: %s", rsp.StatusCode, errorMessage(rsp.Body))
+	}
+
+	var cth types.CosignedTreeHead
+	if err := cth.FromASCII(rsp.Body); err != nil {
+		return nil, fmt.Errorf("client: HTTP %d: %s", rsp.StatusCode, errorMessage(rsp.Body))
+	}
+	return &cth, nil
+}
+
+func (c *NetworkClient) GetInclusionProof(treeSize uint64, leafHash *types.Hash) (*types.InclusionProof, error) {
+	data := requests.InclusionProof{
+		TreeSize: treeSize,
+		LeafHash: *leafHash,
+	}
+	buf := bytes.NewBuffer(nil)
+	if err := data.ToASCII(buf); err != nil {
+		return nil, fmt.Errorf("client: invalid request data: %v", err)
+	}
+
+	rsp, err := c.post(types.EndpointGetInclusionProof.Path(c.LogURL), buf)
+	if err != nil {
+		return nil, fmt.Errorf("client: invalid proof request: %v", err)
+	}
+
+	defer rsp.Body.Close()
+	if rsp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("client: HTTP %d: %s", rsp.StatusCode, errorMessage(rsp.Body))
+	}
+	var proof types.InclusionProof
+	if err := proof.FromASCII(rsp.Body, treeSize); err != nil {
+		return nil, fmt.Errorf("client: failed parsing response: %v", err)
+	}
+
+	return &proof, nil
+}
+
+func (c *NetworkClient) GetConsistencyProof(oldSize, newSize uint64) (*types.ConsistencyProof, error) {
+	return nil, fmt.Errorf("TODO")
+}
+
+func (c *NetworkClient) GetLeaves(startSize, endSize uint64) (*types.Leaves, error) {
+	return nil, fmt.Errorf("TODO")
+}
+
+func (c *NetworkClient) AddLeaf(leaf *requests.Leaf) error {
+	buf := bytes.NewBuffer(nil)
+	if err := leaf.ToASCII(buf); err != nil {
+		return fmt.Errorf("client: invalid request data: %v", err)
+	}
+
+	rsp, err := c.post(types.EndpointAddLeaf.Path(c.LogURL), buf)
+	if err != nil {
+		return fmt.Errorf("client: HTTP %d: %s", rsp.StatusCode, errorMessage(rsp.Body))
+	}
+
+	defer rsp.Body.Close()
+	if rsp.StatusCode != http.StatusOK {
+		return fmt.Errorf("client: HTTP %d: %s", rsp.StatusCode, errorMessage(rsp.Body))
+	}
+	return nil
+}
+
+func (c *NetworkClient) AddCosignature(*requests.Cosignature) error {
+	return fmt.Errorf("TODO")
+}
+
+func (c *NetworkClient) get(url string) (*http.Response, error) {
+	log.Printf("GET %s", url)
+	return c.Get(url)
+}
+
+func (c *NetworkClient) post(url string, buf *bytes.Buffer) (*http.Response, error) {
+	req, err := http.NewRequest("POST", url, buf)
+	if err != nil {
+		return nil, fmt.Errorf("client: invalid leaf request: %v", err)
+	}
+
+	log.Printf("POST %s", url)
+	return c.Do(req)
+}
+
+func errorMessage(r io.Reader) string {
+	b, _ := ioutil.ReadAll(r)
+	return string(b)
+
+	// TODO: the below doesn't work because log error messages are malformed
+	//msg := struct {
+	//	Message string `ascii:"Error"`
+	//}{}
+	//if err := ascii.StdEncoding.Deserialize(r, &msg); err != nil {
+	//	return fmt.Sprintf("malformed error message: %v", err)
+	//}
+	//return msg.Message
+}
diff --git a/pkg/client/submitter.go b/pkg/client/submitter.go
new file mode 100644
index 0000000..f03e66a
--- /dev/null
+++ b/pkg/client/submitter.go
@@ -0,0 +1,129 @@
+package client
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"log"
+	"net/http"
+	"time"
+
+	"git.sigsum.org/sigsum-lib-go/pkg/requests"
+	"git.sigsum.org/sigsum-lib-go/pkg/types"
+	"git.sigsum.org/sigsum-tool-go/pkg/client/api"
+	"git.sigsum.org/sigsum-tool-go/pkg/policy"
+)
+
+type Submitter interface {
+	AddLeaves(context.Context, []requests.Leaf) ([]Bundle, error)
+}
+
+type SubmitClient struct {
+	api    api.API
+	policy policy.Policy
+}
+
+// TODO: should signature+key_hash (not) be in bundle?
+type Bundle struct {
+	ShardHint        uint64
+	Signature        types.Signature
+	KeyHash          types.Hash
+	InclusionProof   types.InclusionProof
+	CosignedTreeHead types.CosignedTreeHead
+}
+
+func NewSubmitClient(policy policy.Policy) *SubmitClient {
+	return &SubmitClient{
+		policy: policy,
+	}
+}
+
+// TODO: feedback on the below sketch; improve it; implement properly.
+// 0. Select one log in policy, setup API network client.
+// 1. Loop over all leaves that have yet to received 200 OK.  Move on to
+// the next leaf on a non-200 status code, trying again next itteration.
+// 3. Try to fetch an inclusion proof for the latest HTTP 200 OK
+// response every time a new cosigned tree head becomes available.
+// Output warning if more than two cosigned tree heads pass.
+// 4. Loop over all leaves and fetch inclusion proofs for X.
+// [Exit with error if any inclusion proof is not available / invalid]
+// 5. Return bundles in the same order as leaves were passed.
+func (sc *SubmitClient) AddLeaves(_ context.Context, leaves []requests.Leaf) ([]Bundle, error) {
+	if err := sc.newAPI(); err != nil {
+		return nil, fmt.Errorf("client: %v", err)
+	}
+
+	for _, leaf := range leaves {
+		err := sc.api.AddLeaf(&leaf)
+		if err != nil {
+			return nil, fmt.Errorf("client: %v", err)
+		}
+	}
+
+	start := time.Now().Unix()
+	var bundles []Bundle
+	for {
+		cth, err := sc.api.GetCosignedTreeHead()
+		if err != nil {
+			return nil, fmt.Errorf("client: %v", err)
+		}
+		// TODO: verify that cth is valid for policy
+
+		ok := true
+		bundles = nil
+		for _, leaf := range leaves {
+			l := types.Leaf{
+				Statement: types.Statement{
+					ShardHint: leaf.ShardHint,
+					Checksum:  leaf.Checksum,
+				},
+				Signature: leaf.Signature,
+				KeyHash:   *types.HashFn(leaf.VerificationKey[:]),
+			}
+			lh := types.HashFn(append([]byte{0x00}, l.ToBinary()...))
+			log.Printf("leaf hash is: %x", lh[:])
+
+			proof, err := sc.api.GetInclusionProof(cth.TreeSize, lh)
+			if err != nil {
+				log.Printf("no inclusion proof for tree size %d yet, please wait.\n", cth.TreeSize)
+				ok = false
+				break
+			}
+
+			// TODO: verify that inclusion proof is valid
+			bundles = append(bundles, Bundle{
+				ShardHint:        l.ShardHint,
+				Signature:        l.Signature,
+				KeyHash:          l.KeyHash,
+				InclusionProof:   *proof,
+				CosignedTreeHead: *cth,
+			})
+		}
+		if ok {
+			break
+		}
+
+		time.Sleep(15 * time.Second)
+		log.Printf("waited %d seconds...\n", time.Now().Unix()-start)
+	}
+
+	return bundles, nil
+}
+
+func (sc *SubmitClient) newAPI() error {
+	// TODO: select a log properly.
+	sc.api = api.NewNetworkClient(http.Client{}, sc.policy.Logs()[0].LogURL)
+	return nil
+}
+
+func (b *Bundle) ToASCII(w io.Writer) error {
+	return fmt.Errorf("TODO")
+}
+
+func (b *Bundle) FromASCII(r io.Reader) error {
+	return fmt.Errorf("TODO")
+}
+
+func (b *Bundle) Verify(k *types.PublicKey, p *policy.Policy, r io.Reader) error {
+	return fmt.Errorf("TODO")
+}
diff --git a/pkg/policy/default.go b/pkg/policy/default.go
new file mode 100644
index 0000000..6f35fa4
--- /dev/null
+++ b/pkg/policy/default.go
@@ -0,0 +1,66 @@
+package policy
+
+import (
+	"fmt"
+
+	"git.sigsum.org/sigsum-lib-go/pkg/types"
+)
+
+type DefaultPolicy struct{}
+
+// Verify checks if the cosigned tree head satisifies the policy "one log and
+// a majority of witnesses".  Any unverifiable cosignatures are removed.
+func (dp *DefaultPolicy) Verify(*types.CosignedTreeHead) error {
+	return fmt.Errorf("TODO")
+}
+
+func (dp *DefaultPolicy) Logs() []Log {
+	return []Log{
+		Log{
+			Name:   "Test log operated by ln5",
+			LogURL: "https://poc.sigsum.org/glasswing-butterfly/sigsum/v0",
+			PublicKey: types.PublicKey{
+				74, 179, 210, 181,
+				30, 71, 220, 157,
+				228, 204, 228, 189,
+				235, 169, 224, 134,
+				34, 233, 58, 47,
+				127, 137, 180, 203,
+				119, 25, 127, 198,
+				176, 4, 77, 231,
+			},
+			ShardStart: 1639579652,
+			TrustUntil: 1648771200, // Apr 1 2022
+		},
+	}
+}
+
+func (dp *DefaultPolicy) Witnesses() []Witness {
+	return []Witness{
+		Witness{
+			Name: "Test witness operated by rgdd",
+			PublicKey: types.PublicKey{
+				129, 45, 190, 240,
+				21, 107, 7, 158,
+				45, 4, 135, 71,
+				178, 24, 156, 191,
+				166, 79, 150, 226,
+				32, 74, 23, 203,
+				35, 203, 82, 128,
+				128, 135, 21, 3,
+			},
+			TrustUntil: 1648771200, // Apr 1 2022
+		},
+	}
+}
+
+// ShardHint returns the smallest shard hint that all logs accept
+func (dp *DefaultPolicy) ShardHint() uint64 {
+	var shardHint uint64
+	for _, l := range dp.Logs() {
+		if l.ShardStart > shardHint {
+			shardHint = l.ShardStart
+		}
+	}
+	return shardHint
+}
diff --git a/pkg/policy/policy.go b/pkg/policy/policy.go
new file mode 100644
index 0000000..b4fe920
--- /dev/null
+++ b/pkg/policy/policy.go
@@ -0,0 +1,32 @@
+package policy
+
+import (
+	"git.sigsum.org/sigsum-lib-go/pkg/types"
+)
+
+type Policy interface {
+	// Logs returns the list of known logs.  It is needed so that an
+	// appropriate log can be picked when submitting a signed checksum.
+	Logs() []Log
+
+	// ShardHint returns a recommended shard hint.
+	ShardHint() uint64
+
+	// Verify checks if a cosigned tree head is trustworthy.  On success,
+	// any invalid or unknown cosignatures may be removed.
+	Verify(*types.CosignedTreeHead) error
+}
+
+type Log struct {
+	Name       string
+	LogURL     string
+	PublicKey  types.PublicKey
+	ShardStart uint64
+	TrustUntil uint64
+}
+
+type Witness struct {
+	Name       string
+	PublicKey  types.PublicKey
+	TrustUntil uint64
+}
diff --git a/pkg/signatures/minisign/minisign.go b/pkg/signatures/minisign/minisign.go
new file mode 100644
index 0000000..8d8a9c4
--- /dev/null
+++ b/pkg/signatures/minisign/minisign.go
@@ -0,0 +1,22 @@
+package minisign
+
+import (
+	"fmt"
+	"io"
+
+	"git.sigsum.org/sigsum-lib-go/pkg/types"
+)
+
+type Parser struct{}
+
+func (p *Parser) SignatureSuffix() string {
+	return ".minisig"
+}
+
+func (p *Parser) PublicKey(r io.Reader) (*types.PublicKey, error) {
+	return nil, fmt.Errorf("TODO")
+}
+
+func (p *Parser) Signature(r io.Reader) (*types.Signature, error) {
+	return nil, fmt.Errorf("TODO")
+}
diff --git a/pkg/signatures/signatures.go b/pkg/signatures/signatures.go
new file mode 100644
index 0000000..184c8f3
--- /dev/null
+++ b/pkg/signatures/signatures.go
@@ -0,0 +1,13 @@
+package signatures
+
+import (
+	"io"
+
+	"git.sigsum.org/sigsum-lib-go/pkg/types"
+)
+
+type Parser interface {
+	PublicKey(io.Reader) (*types.PublicKey, error)
+	Signature(io.Reader) (*types.Signature, error)
+	SignatureSuffix() string
+}
diff --git a/pkg/signatures/signify/signify.go b/pkg/signatures/signify/signify.go
new file mode 100644
index 0000000..6dbbf07
--- /dev/null
+++ b/pkg/signatures/signify/signify.go
@@ -0,0 +1,91 @@
+package signify
+
+import (
+	"bytes"
+	"encoding/base64"
+	"fmt"
+	"io"
+	"io/ioutil"
+
+	"git.sigsum.org/sigsum-lib-go/pkg/types"
+)
+
+type Parser struct{}
+
+func (p *Parser) SignatureSuffix() string {
+	return ".sig"
+}
+
+func (p *Parser) PublicKey(r io.Reader) (*types.PublicKey, error) {
+	b, err := ioutil.ReadAll(r)
+	if err != nil {
+		return nil, fmt.Errorf("signify: read failed: %v", err)
+	}
+	var pub types.PublicKey
+	if err := parse(pub[:], b); err != nil {
+		return nil, fmt.Errorf("signify: %v", err)
+	}
+	return &pub, nil
+}
+
+func (p *Parser) Signature(r io.Reader) (*types.Signature, error) {
+	b, err := ioutil.ReadAll(r)
+	if err != nil {
+		return nil, fmt.Errorf("signify: read failed: %v", err)
+	}
+	var sig types.Signature
+	if err := parse(sig[:], b); err != nil {
+		return nil, fmt.Errorf("signify: %v", err)
+	}
+	return &sig, nil
+}
+
+func parse(dst, lines []byte) error {
+	commentLine, dataLine, err := parseLines(lines)
+	if err != nil {
+		return fmt.Errorf("invalid: %v", err)
+	}
+	if err := parseCommentLine(commentLine); err != nil {
+		return fmt.Errorf("invalid: %v", err)
+	}
+	if err := parseDataLine(dst, dataLine); err != nil {
+		return fmt.Errorf("invalid: %v", err)
+	}
+	return nil
+}
+
+func parseLines(lines []byte) ([]byte, []byte, error) {
+	split := bytes.Split(lines, []byte("\n"))
+	if len(split) != 3 {
+		return nil, nil, fmt.Errorf("number of lines")
+	}
+	return split[0], split[1], nil
+}
+
+func parseCommentLine(line []byte) error {
+	if !bytes.HasPrefix(line, []byte("untrusted comment: ")) {
+		return fmt.Errorf("no untrusted comment")
+	}
+	return nil
+}
+
+func parseDataLine(dst, line []byte) error {
+	data, err := base64.StdEncoding.DecodeString(string(line))
+	if err != nil {
+		return fmt.Errorf("base64 encoding")
+	}
+	if len(data) < 2 || !bytes.Equal(data[:2], []byte("Ed")) {
+		return fmt.Errorf("algorithm")
+	}
+	data = data[2:]
+	if len(data) < 8 {
+		return fmt.Errorf("random fingerprint")
+	}
+	data = data[8:]
+	if len(data) != len(dst) {
+		return fmt.Errorf("data length")
+	}
+
+	copy(dst[:], data)
+	return nil
+}
diff --git a/pkg/signatures/ssh/ssh.go b/pkg/signatures/ssh/ssh.go
new file mode 100644
index 0000000..d5fb8f4
--- /dev/null
+++ b/pkg/signatures/ssh/ssh.go
@@ -0,0 +1,22 @@
+package ssh
+
+import (
+	"fmt"
+	"io"
+
+	"git.sigsum.org/sigsum-lib-go/pkg/types"
+)
+
+type Parser struct{}
+
+func (p *Parser) SignatureSuffix() string {
+	return ".sig"
+}
+
+func (p *Parser) PublicKey(r io.Reader) (*types.PublicKey, error) {
+	return nil, fmt.Errorf("TODO")
+}
+
+func (p *Parser) Signature(r io.Reader) (*types.Signature, error) {
+	return nil, fmt.Errorf("TODO")
+}