GPG commit validation

Author: sapk

models/gpg_key.go

@@ -6,13 +6,21 @@ package models
 
 import (
 	"bytes"
+	"container/list"
+	"crypto"
 	"encoding/base64"
 	"fmt"
+	"hash"
+	"io"
 	"strings"
 	"time"
 
+	"code.gitea.io/git"
+
 	"github.com/go-xorm/xorm"
+	"github.com/ngaut/log"
 	"golang.org/x/crypto/openpgp"
+	"golang.org/x/crypto/openpgp/armor"
 	"golang.org/x/crypto/openpgp/packet"
 )
 
@@ -274,3 +282,181 @@ func DeleteGPGKey(doer *User, id int64) (err error) {
 
 	return nil
 }
+
+// CommitVerification represents a commit validation of signature
+type CommitVerification struct {
+	Verified    bool
+	Reason      string
+	SigningUser *User
+	SigningKey  *GPGKey
+}
+
+// SignCommit represents a commit with validation of signature.
+type SignCommit struct {
+	Verification *CommitVerification
+	*UserCommit
+}
+
+func readerFromBase64(s string) (io.Reader, error) {
+	bs, err := base64.StdEncoding.DecodeString(s)
+	if err != nil {
+		return nil, err
+	}
+	return bytes.NewBuffer(bs), nil
+}
+
+func populateHash(hashFunc crypto.Hash, msg []byte) (hash.Hash, error) {
+	h := hashFunc.New()
+	if _, err := h.Write(msg); err != nil {
+		return nil, err
+	}
+	return h, nil
+}
+
+// readArmoredSign reads an armored signture block with the given type. https://sourcegraph.com/github.com/golang/crypto/-/blob/openpgp/read.go#L24:6-24:17
+func readArmoredSign(r io.Reader) (body io.Reader, err error) {
+	expectedType := "PGP SIGNATURE"
+	block, err := armor.Decode(r)
+	if err != nil {
+		return
+	}
+	if block.Type != expectedType {
+		return nil, fmt.Errorf("expected '" + expectedType + "', got: " + block.Type)
+	}
+	return block.Body, nil
+}
+
+func extractSignature(s string) (*packet.Signature, error) {
+	r, err := readArmoredSign(strings.NewReader(s))
+	if err != nil {
+		return nil, fmt.Errorf("Failed to read signature armor")
+	}
+	p, err := packet.Read(r)
+	if err != nil {
+		return nil, fmt.Errorf("Failed to read signature packet")
+	}
+	sig, ok := p.(*packet.Signature)
+	if !ok {
+		return nil, fmt.Errorf("Packet is not a signature")
+	}
+	return sig, nil
+}
+
+func verifySign(s *packet.Signature, h hash.Hash, k *GPGKey) error {
+	//Check if key can sign
+	if !k.CanSign {
+		return fmt.Errorf("key can not sign")
+	}
+	//Decode key
+	b, err := readerFromBase64(k.Content)
+	if err != nil {
+		return err
+	}
+	//Read key
+	p, err := packet.Read(b)
+	if err != nil {
+		return err
+	}
+
+	//Check type
+	pkey, ok := p.(*packet.PublicKey)
+	if !ok {
+		return fmt.Errorf("key is not a public key")
+	}
+
+	return pkey.VerifySignature(h, s)
+}
+
+// ParseCommitWithSignature check if signature is good against keystore.
+func ParseCommitWithSignature(c *git.Commit) *CommitVerification {
+
+	if c.Signature != nil {
+
+		//Parsing signature
+		sig, err := extractSignature(c.Signature.Signature)
+		if err != nil { //Skipping failed to extract sign
+			log.Error(3, "SignatureRead err: %v", err)
+			return &CommitVerification{
+				Verified: false,
+				Reason:   "Failed to extract signature",
+			}
+		}
+		//Generating hash of commit
+		hash, err := populateHash(sig.Hash, []byte(c.Signature.Payload))
+		if err != nil { //Skipping ailed to generate hash
+			log.Error(3, "PopulateHash: %v", err)
+			return &CommitVerification{
+				Verified: false,
+				Reason:   "Failed to generate hash of commit",
+			}
+		}
+
+		//Find Committer account
+		committer, err := GetUserByEmail(c.Committer.Email)
+		if err != nil { //Skipping not user for commiter
+			log.Error(3, "NoCommitterAccount: %v", err)
+			return &CommitVerification{
+				Verified: false,
+				Reason:   "No account linked to committer email",
+			}
+		}
+
+		keys, err := ListGPGKeys(committer.ID)
+		if err != nil { //Skipping failed to get gpg keys of user
+			log.Error(3, "ListGPGKeys: %v", err)
+			return &CommitVerification{
+				Verified: false,
+				Reason:   "Failed to retrieve publics keys of committer",
+			}
+		}
+
+		for _, k := range keys {
+			//We get PK
+			if err := verifySign(sig, hash, k); err == nil {
+				return &CommitVerification{ //Everything is ok
+					Verified:    true,
+					Reason:      fmt.Sprintf("%s <%s> / %s", c.Committer.Name, c.Committer.Email, k.KeyID),
+					SigningUser: committer,
+					SigningKey:  k,
+				}
+			}
+			//And test also SubsKey
+			for _, sk := range k.SubsKey {
+				if err := verifySign(sig, hash, sk); err == nil {
+					return &CommitVerification{ //Everything is ok
+						Verified:    true,
+						Reason:      fmt.Sprintf("%s <%s> / %s", c.Committer.Name, c.Committer.Email, sk.KeyID),
+						SigningUser: committer,
+						SigningKey:  sk,
+					}
+				}
+			}
+		}
+		return &CommitVerification{ //Default at this stage
+			Verified: false,
+			Reason:   "No known key found for this signature in database",
+		}
+	}
+
+	return &CommitVerification{
+		Verified: false,                 //Default value
+		Reason:   "Not a signed commit", //Default value
+	}
+}
+
+// ParseCommitsWithSignature checks if signaute of commits are corresponding to users gpg keys.
+func ParseCommitsWithSignature(oldCommits *list.List) *list.List {
+	var (
+		newCommits = list.New()
+		e          = oldCommits.Front()
+	)
+	for e != nil {
+		c := e.Value.(UserCommit)
+		newCommits.PushBack(SignCommit{
+			UserCommit:   &c,
+			Verification: ParseCommitWithSignature(c.Commit),
+		})
+		e = e.Next()
+	}
+	return newCommits
+}

public/css/index.css

@@ -1924,8 +1924,29 @@ footer .ui.language .menu {
   padding-left: 15px;
 }
 .repository #commits-table thead .sha {
-  font-size: 13px;
-  padding: 6px 40px 4px 35px;
+  text-align: center;
+  width: 140px;
+}
+.repository #commits-table td.sha .sha.label {
+  margin: 0;
+}
+.repository #commits-table td.sha .sha.label.isSigned {
+  border: 1px solid #BBB;
+}
+.repository #commits-table td.sha .sha.label.isSigned .detail.icon {
+  background: #FAFAFA;
+  margin: -6px -10px -4px 0px;
+  padding: 5px 3px 5px 6px;
+  border-left: 1px solid #BBB;
+  border-top-left-radius: 0;
+  border-bottom-left-radius: 0;
+}
+.repository #commits-table td.sha .sha.label.isSigned.isVerified {
+  border: 1px solid #21BA45;
+  background: #21BA4518;
+}
+.repository #commits-table td.sha .sha.label.isSigned.isVerified .detail.icon {
+  border-left: 1px solid #21BA4580;
 }
 .repository #commits-table.ui.basic.striped.table tbody tr:nth-child(2n) {
   background-color: rgba(0, 0, 0, 0.02) !important;
@@ -2239,6 +2260,16 @@ footer .ui.language .menu {
   margin-left: 26px;
   padding-top: 0;
 }
+.repository .ui.attached.isSigned.isVerified:not(.positive) {
+  border-left: 1px solid #A3C293;
+  border-right: 1px solid #A3C293;
+}
+.repository .ui.attached.isSigned.isVerified.top:not(.positive) {
+  border-top: 1px solid #A3C293;
+}
+.repository .ui.attached.isSigned.isVerified:not(.positive):last-child {
+  border-bottom: 1px solid #A3C293;
+}
 .user-cards .list {
   padding: 0;
 }

public/less/_repository.less

@@ -800,8 +800,31 @@
 				padding-left: 15px;
 			}
 			.sha {
-				font-size: 13px;
-				padding: 6px 40px 4px 35px;
+				text-align: center;
+				width: 140px;
+			}
+		}
+		td.sha{
+			.sha.label{
+				margin: 0;
+				&.isSigned{
+					border: 1px solid #BBB;
+					.detail.icon{
+						background: #FAFAFA;
+						margin: -6px -10px -4px 0px;
+						padding: 5px 3px 5px 6px;
+						border-left: 1px solid #BBB;
+						border-top-left-radius: 0;
+						border-bottom-left-radius: 0;
+					}
+				}
+				&.isSigned.isVerified{
+					border: 1px solid #21BA45;
+					background: #21BA4518;
+					.detail.icon{
+						border-left: 1px solid #21BA4580;
+					}
+				}
 			}
 		}
 		&.ui.basic.striped.table tbody tr:nth-child(2n) {
@@ -1206,6 +1229,18 @@
 			}
 		}
 	}
+	.ui.attached.isSigned.isVerified{
+        &:not(.positive){
+		    border-left: 1px solid #A3C293;
+		    border-right: 1px solid #A3C293;
+	    }
+	    &.top:not(.positive){
+		    border-top: 1px solid #A3C293;
+	    }
+        &:not(.positive):last-child {
+            border-bottom: 1px solid #A3C293;
+        }
+	}
 }
 // End of .repository
 

routers/api/v1/convert/convert.go

@@ -44,6 +44,7 @@ func ToCommit(c *git.Commit) *api.PayloadCommit {
 	if err == nil {
 		committerUsername = committer.Name
 	}
+	verif := models.ParseCommitWithSignature(c)
 	return &api.PayloadCommit{
 		ID:      c.ID.String(),
 		Message: c.Message(),
@@ -59,6 +60,12 @@ func ToCommit(c *git.Commit) *api.PayloadCommit {
 			UserName: committerUsername,
 		},
 		Timestamp: c.Author.When,
+		Verification: &api.PayloadCommitVerification{
+			Verified:  verif.Verified,
+			Reason:    verif.Reason,
+			Signature: c.Signature.Signature,
+			Payload:   c.Signature.Payload,
+		},
 	}
 }
 

routers/repo/commit.go

@@ -68,6 +68,7 @@ func Commits(ctx *context.Context) {
 	}
 	commits = renderIssueLinks(commits, ctx.Repo.RepoLink)
 	commits = models.ValidateCommitsWithEmails(commits)
+	commits = models.ParseCommitsWithSignature(commits)
 	ctx.Data["Commits"] = commits
 
 	ctx.Data["Username"] = ctx.Repo.Owner.Name
@@ -121,6 +122,7 @@ func SearchCommits(ctx *context.Context) {
 	}
 	commits = renderIssueLinks(commits, ctx.Repo.RepoLink)
 	commits = models.ValidateCommitsWithEmails(commits)
+	commits = models.ParseCommitsWithSignature(commits)
 	ctx.Data["Commits"] = commits
 
 	ctx.Data["Keyword"] = keyword
@@ -167,6 +169,7 @@ func FileHistory(ctx *context.Context) {
 	}
 	commits = renderIssueLinks(commits, ctx.Repo.RepoLink)
 	commits = models.ValidateCommitsWithEmails(commits)
+	commits = models.ParseCommitsWithSignature(commits)
 	ctx.Data["Commits"] = commits
 
 	ctx.Data["Username"] = ctx.Repo.Owner.Name
@@ -222,6 +225,7 @@ func Diff(ctx *context.Context) {
 	ctx.Data["IsImageFile"] = commit.IsImageFile
 	ctx.Data["Title"] = commit.Summary() + " · " + base.ShortSha(commitID)
 	ctx.Data["Commit"] = commit
+	ctx.Data["Verification"] = models.ParseCommitWithSignature(commit)
 	ctx.Data["Author"] = models.ValidateCommitWithEmail(commit)
 	ctx.Data["Diff"] = diff
 	ctx.Data["Parents"] = parents
@@ -276,6 +280,7 @@ func CompareDiff(ctx *context.Context) {
 		return
 	}
 	commits = models.ValidateCommitsWithEmails(commits)
+	commits = models.ParseCommitsWithSignature(commits)
 
 	ctx.Data["CommitRepoLink"] = ctx.Repo.RepoLink
 	ctx.Data["Commits"] = commits

templates/repo/commits_table.tmpl

@@ -21,7 +21,8 @@
 			<thead>
 				<tr>
 					<th class="four wide">{{.i18n.Tr "repo.commits.author"}}</th>
-					<th class="nine wide message"><span class="sha">SHA1</span> {{.i18n.Tr "repo.commits.message"}}</th>
+					<th class="two wide sha">SHA1</th>
+					<th class="seven wide message">{{.i18n.Tr "repo.commits.message"}}</th>
 					<th class="three wide right aligned">{{.i18n.Tr "repo.commits.date"}}</th>
 				</tr>
 			</thead>
@@ -40,9 +41,17 @@
 								<img class="ui avatar image" src="{{AvatarLink .Author.Email}}" alt=""/>&nbsp;&nbsp;{{.Author.Name}}
 							{{end}}
 						</td>
-
+						<td class="sha">
+							<a rel="nofollow" class="ui sha label {{if .Signature}} isSigned {{if .Verification.Verified }} isVerified {{end}}{{end}}" href="{{AppSubUrl}}/{{$.Username}}/{{$.Reponame}}/commit/{{.ID}}">
+								{{ShortSha .ID.String}}
+								{{if .Signature}}
+									<div class="ui detail icon button">
+										<i title="{{.Verification.Reason}}" class="{{if .Verification.Verified }}lock green{{else}}unlock{{end}} icon"></i>
+									</div>
+								{{end}}
+							</a>
+						</td>
 						<td class="message collapsing">
-							<a rel="nofollow" class="ui sha label" href="{{AppSubUrl}}/{{$.Username}}/{{$.Reponame}}/commit/{{.ID}}">{{ShortSha .ID.String}}</a>
 							<span class="has-emoji{{if gt .ParentCount 1}} grey text{{end}}">{{RenderCommitMessage false .Summary $.RepoLink $.Repository.ComposeMetas}}</span>
 						</td>
 						<td class="grey text right aligned">{{TimeSince .Author.When $.Lang}}</td>