1 files changed, 108 insertions, 0 deletions
diff --git a/internal/slackware_com/crypto.go b/internal/slackware_com/crypto.go
new file mode 100644
index 0000000..60bdca2
--- /dev/null
+++ b/internal/slackware_com/crypto.go
@@ -0,0 +1,108 @@
+package slackware_com
+
+import (
+	"bytes"
+	_ "embed"
+	"io"
+	"os"
+	"os/exec"
+)
+
+//go:embed "security@slackware.com.asc"
+var slackwareGPGKey string
+
+type GnuPGVerifier struct {
+	w      *io.PipeWriter
+	result <-chan struct {
+		bool
+		error
+	}
+}
+
+func RunSignatureVerifier(signature string) *GnuPGVerifier {
+	var v GnuPGVerifier
+
+	r, w := io.Pipe()
+	v.w = w
+
+	result := make(chan struct {
+		bool
+		error
+	}, 1)
+	v.result = result
+
+	go v.executeCMD(result, r, signature)
+
+	return &v
+}
+
+func (g *GnuPGVerifier) executeCMD(c chan<- struct {
+	bool
+	error
+}, r io.ReadCloser, signature string) {
+	defer close(c)
+	defer r.Close()
+
+	sigFile, err := os.CreateTemp("", "gpg-signature.*")
+	if err != nil {
+		c <- struct {
+			bool
+			error
+		}{false, err}
+		return
+	}
+	defer sigFile.Close()
+	defer os.Remove(sigFile.Name())
+
+	sigFile.WriteString(signature)
+	sigFile.Close()
+
+	var keyRing bytes.Buffer
+	cmd := exec.Command("gpg2", "--dearmor")
+	cmd.Stdin = bytes.NewBufferString(slackwareGPGKey)
+	cmd.Stdout = &keyRing
+	err = cmd.Run()
+	if err != nil {
+		c <- struct {
+			bool
+			error
+		}{false, err}
+		return
+	}
+
+	keyRingFile, err := os.CreateTemp("", "gpg-keyring.*.gpg")
+	if err != nil {
+		c <- struct {
+			bool
+			error
+		}{false, err}
+		return
+	}
+	defer keyRingFile.Close()
+	defer os.Remove(keyRingFile.Name())
+
+	keyRingFile.Write(keyRing.Bytes())
+	keyRingFile.Close()
+
+	cmd = exec.Command("gpg2",
+		"--no-default-keyring",
+		"--keyring", keyRingFile.Name(),
+		"--verify", sigFile.Name(), "-",
+	)
+	cmd.Stdin = r
+	err = cmd.Run()
+	c <- struct {
+		bool
+		error
+	}{err == nil, err}
+}
+
+func (g *GnuPGVerifier) Write(buf []byte) (int, error) {
+	return g.w.Write(buf)
+}
+
+func (g *GnuPGVerifier) IsValid() (bool, error) {
+	g.w.Close()
+	res := <-g.result
+	return res.bool, res.error
+}