1 files changed, 241 insertions, 0 deletions
diff --git a/activitypub/pem.go b/activitypub/pem.go
new file mode 100644
index 0000000..ca6c068
--- /dev/null
+++ b/activitypub/pem.go
@@ -0,0 +1,241 @@
+package activitypub
+
+import (
+	crand "crypto/rand"
+	"crypto/rsa"
+	"crypto/x509"
+	"encoding/pem"
+	"errors"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"regexp"
+	"strings"
+
+	"github.com/FChannel0/FChannel-Server/config"
+)
+
+type Signature struct {
+	KeyId     string
+	Headers   []string
+	Signature string
+	Algorithm string
+}
+
+func CreatePem(actor Actor) error {
+	privatekey, err := rsa.GenerateKey(crand.Reader, 2048)
+	if err != nil {
+		return err
+	}
+
+	privateKeyBytes := x509.MarshalPKCS1PrivateKey(privatekey)
+
+	privateKeyBlock := &pem.Block{
+		Type:  "RSA PRIVATE KEY",
+		Bytes: privateKeyBytes,
+	}
+
+	privatePem, err := os.Create("./pem/board/" + actor.Name + "-private.pem")
+	if err != nil {
+		return err
+	}
+
+	if err := pem.Encode(privatePem, privateKeyBlock); err != nil {
+		return err
+	}
+
+	publickey := &privatekey.PublicKey
+	publicKeyBytes, err := x509.MarshalPKIXPublicKey(publickey)
+	if err != nil {
+		return err
+	}
+
+	publicKeyBlock := &pem.Block{
+		Type:  "PUBLIC KEY",
+		Bytes: publicKeyBytes,
+	}
+
+	publicPem, err := os.Create("./pem/board/" + actor.Name + "-public.pem")
+	if err != nil {
+		return err
+	}
+
+	if err := pem.Encode(publicPem, publicKeyBlock); err != nil {
+		return err
+	}
+
+	_, err = os.Stat("./pem/board/" + actor.Name + "-public.pem")
+	if os.IsNotExist(err) {
+		return err
+	} else {
+		return StorePemToDB(actor)
+	}
+
+	fmt.Println(`Created PEM keypair for the "` + actor.Name + `" board. Please keep in mind that
+the PEM key is crucial in identifying yourself as the legitimate owner of the board,
+so DO NOT LOSE IT!!! If you lose it, YOU WILL LOSE ACCESS TO YOUR BOARD!`)
+
+	return nil
+}
+
+func CreatePublicKeyFromPrivate(actor *Actor, publicKeyPem string) error {
+	publicFilename, err := GetActorPemFileFromDB(publicKeyPem)
+	if err != nil {
+		return err
+	}
+
+	privateFilename := strings.ReplaceAll(publicFilename, "public.pem", "private.pem")
+	if _, err := os.Stat(privateFilename); err == nil {
+		// Not a lost cause
+		priv, err := ioutil.ReadFile(privateFilename)
+		if err != nil {
+			return err
+		}
+
+		block, _ := pem.Decode([]byte(priv))
+		if block == nil || block.Type != "RSA PRIVATE KEY" {
+			return errors.New("failed to decode PEM block containing public key")
+		}
+
+		key, err := x509.ParsePKCS1PrivateKey(block.Bytes)
+		if err != nil {
+			return err
+		}
+
+		publicKeyDer, err := x509.MarshalPKIXPublicKey(&key.PublicKey)
+		if err != nil {
+			return err
+		}
+
+		pubKeyBlock := pem.Block{
+			Type:    "PUBLIC KEY",
+			Headers: nil,
+			Bytes:   publicKeyDer,
+		}
+
+		publicFileWriter, err := os.Create(publicFilename)
+		if err != nil {
+			return err
+		}
+
+		if err := pem.Encode(publicFileWriter, &pubKeyBlock); err != nil {
+			return err
+		}
+	} else {
+		fmt.Println(`\nUnable to locate private key from public key generation. Now,
+this means that you are now missing the proof that you are the
+owner of the "` + actor.Name + `" board. If you are the developer,
+then your job is just as easy as generating a new keypair, but
+if this board is live, then you'll also have to convince the other
+owners to switch their public keys for you so that they will start
+accepting your posts from your board from this site. Good luck ;)`)
+		return errors.New("unable to locate private key")
+	}
+	return nil
+}
+
+func GetActorPemFromDB(pemID string) (PublicKeyPem, error) {
+	var pem PublicKeyPem
+
+	query := `select id, owner, file from publickeypem where id=$1`
+
+	rows, err := config.DB.Query(query, pemID)
+	if err != nil {
+		return pem, err
+	}
+
+	defer rows.Close()
+
+	rows.Next()
+	rows.Scan(&pem.Id, &pem.Owner, &pem.PublicKeyPem)
+	f, err := os.ReadFile(pem.PublicKeyPem)
+	if err != nil {
+		return pem, err
+	}
+
+	pem.PublicKeyPem = strings.ReplaceAll(string(f), "\r\n", `\n`)
+
+	return pem, nil
+}
+
+func GetActorPemFileFromDB(pemID string) (string, error) {
+	query := `select file from publickeypem where id=$1`
+	rows, err := config.DB.Query(query, pemID)
+	if err != nil {
+		return "", err
+	}
+
+	defer rows.Close()
+
+	var file string
+	rows.Next()
+	rows.Scan(&file)
+
+	return file, nil
+}
+
+func StorePemToDB(actor Actor) error {
+	query := "select publicKeyPem from actor where id=$1"
+	rows, err := config.DB.Query(query, actor.Id)
+	if err != nil {
+		return err
+	}
+
+	defer rows.Close()
+
+	var result string
+	rows.Next()
+	rows.Scan(&result)
+
+	if result != "" {
+		return errors.New("already storing public key for actor")
+	}
+
+	publicKeyPem := actor.Id + "#main-key"
+	query = "update actor set publicKeyPem=$1 where id=$2"
+	if _, err := config.DB.Exec(query, publicKeyPem, actor.Id); err != nil {
+		return err
+	}
+
+	file := "./pem/board/" + actor.Name + "-public.pem"
+	query = "insert into publicKeyPem (id, owner, file) values($1, $2, $3)"
+	_, err = config.DB.Exec(query, publicKeyPem, actor.Id, file)
+	return err
+}
+
+func ParseHeaderSignature(signature string) Signature {
+	var nsig Signature
+
+	keyId := regexp.MustCompile(`keyId=`)
+	headers := regexp.MustCompile(`headers=`)
+	sig := regexp.MustCompile(`signature=`)
+	algo := regexp.MustCompile(`algorithm=`)
+
+	signature = strings.ReplaceAll(signature, "\"", "")
+	parts := strings.Split(signature, ",")
+
+	for _, e := range parts {
+		if keyId.MatchString(e) {
+			nsig.KeyId = keyId.ReplaceAllString(e, "")
+			continue
+		}
+
+		if headers.MatchString(e) {
+			header := headers.ReplaceAllString(e, "")
+			nsig.Headers = strings.Split(header, " ")
+			continue
+		}
+
+		if sig.MatchString(e) {
+			nsig.Signature = sig.ReplaceAllString(e, "")
+			continue
+		}
+
+		if algo.MatchString(e) {
+			nsig.Algorithm = algo.ReplaceAllString(e, "")
+			continue
+		}
+	}
+
+	return nsig
+}