Initial support for PGP decryption & signatures

1 files changed, 93 insertions, 0 deletions

diff --git a/widgets/pgpinfo.go b/widgets/pgpinfo.go
new file mode 100644
index 0000000..b6a7a16
--- /dev/null
+++ b/widgets/pgpinfo.go
@@ -0,0 +1,93 @@
+package widgets
+
+import (
+	"errors"
+
+	"git.sr.ht/~sircmpwn/aerc/lib/ui"
+
+	"github.com/gdamore/tcell"
+	"golang.org/x/crypto/openpgp"
+	pgperrors "golang.org/x/crypto/openpgp/errors"
+)
+
+type PGPInfo struct {
+	ui.Invalidatable
+	details *openpgp.MessageDetails
+}
+
+func NewPGPInfo(details *openpgp.MessageDetails) *PGPInfo {
+	return &PGPInfo{details: details}
+}
+
+func (p *PGPInfo) DrawSignature(ctx *ui.Context, offs bool) {
+	errorStyle := tcell.StyleDefault.Background(tcell.ColorRed).
+		Foreground(tcell.ColorWhite).Bold(true)
+	softErrorStyle := tcell.StyleDefault.Foreground(tcell.ColorYellow).
+		Reverse(true).Bold(true)
+	validStyle := tcell.StyleDefault.Foreground(tcell.ColorGreen).Bold(true)
+	header := "Signature "
+	if offs {
+		header += " "
+	}
+
+	// TODO: Nicer prompt for TOFU, fetch from keyserver, etc
+	if errors.Is(p.details.SignatureError, pgperrors.ErrUnknownIssuer) ||
+		p.details.SignedBy == nil {
+
+		x := ctx.Printf(0, 0, tcell.StyleDefault.Bold(true), "%s", header)
+		x += ctx.Printf(x, 0, softErrorStyle, " Unknown ")
+		x += ctx.Printf(x, 0, tcell.StyleDefault,
+			" Signed with unknown key (%8X); authenticity unknown",
+			p.details.SignedByKeyId)
+	} else if p.details.SignatureError != nil {
+		x := ctx.Printf(0, 0, tcell.StyleDefault.Bold(true), "%s", header)
+		x += ctx.Printf(x, 0, errorStyle, " ✗ Invalid! ")
+		x += ctx.Printf(x, 0, tcell.StyleDefault.
+			Foreground(tcell.ColorRed).Bold(true),
+			" This message may have been tampered with! (%s)",
+			p.details.SignatureError.Error())
+	} else {
+		entity := p.details.SignedBy.Entity
+		var ident *openpgp.Identity
+		// TODO: Pick identity more intelligently
+		for _, ident = range entity.Identities {
+			break
+		}
+		ctx.Fill(0, 0, ctx.Width(), ctx.Height(), ' ', validStyle)
+		x := ctx.Printf(0, 0, tcell.StyleDefault.Bold(true), "%s", header)
+		x += ctx.Printf(x, 0, validStyle, "✓ Signed ")
+		x += ctx.Printf(x, 0, tcell.StyleDefault,
+			"by %s (%8X)", ident.Name, p.details.SignedByKeyId)
+	}
+}
+
+func (p *PGPInfo) DrawEncryption(ctx *ui.Context, y int) {
+	validStyle := tcell.StyleDefault.Foreground(tcell.ColorGreen).Bold(true)
+	entity := p.details.DecryptedWith.Entity
+	var ident *openpgp.Identity
+	// TODO: Pick identity more intelligently
+	for _, ident = range entity.Identities {
+		break
+	}
+
+	x := ctx.Printf(0, y, tcell.StyleDefault.Bold(true), "Encryption ")
+	x += ctx.Printf(x, y, validStyle, "✓ Encrypted ")
+	x += ctx.Printf(x, y, tcell.StyleDefault,
+		"for %s (%8X) ", ident.Name, p.details.DecryptedWith.PublicKey.KeyId)
+}
+
+func (p *PGPInfo) Draw(ctx *ui.Context) {
+	ctx.Fill(0, 0, ctx.Width(), ctx.Height(), ' ', tcell.StyleDefault)
+	if p.details.IsSigned && p.details.IsEncrypted {
+		p.DrawSignature(ctx, true)
+		p.DrawEncryption(ctx, 1)
+	} else if p.details.IsSigned {
+		p.DrawSignature(ctx, false)
+	} else if p.details.IsEncrypted {
+		p.DrawEncryption(ctx, 0)
+	}
+}
+
+func (p *PGPInfo) Invalidate() {
+	p.DoInvalidate(p)
+}