From 4fda84e737505f2604b87e6a4de63c25f4830631 Mon Sep 17 00:00:00 2001
From: Khanh Dinh Nguyen <77538987+beiryu@users.noreply.github.com>
Date: Thu, 15 Oct 2026 07:13:33 +0700
Subject: [PATCH 1/2] fix(controlplane): return error on short attestation
 state ciphertext

Fixes #3600

Signed-off-by: Khanh Dinh Nguyen <77538987+beiryu@users.noreply.github.com>
---
 app/controlplane/pkg/biz/attestationstate.go  |  4 +++
 .../pkg/biz/attestationstate_test.go          | 31 +++++++++++++++++++
 2 files changed, 35 insertions(+)

diff --git a/app/controlplane/pkg/biz/attestationstate.go b/app/controlplane/pkg/biz/attestationstate.go
index af4da45a3..7e3b4af8a 100644
--- a/app/controlplane/pkg/biz/attestationstate.go
+++ b/app/controlplane/pkg/biz/attestationstate.go
@@ -272,6 +272,10 @@ func decrypt(ciphertext []byte, passphrase string) ([]byte, error) {
 	stream := cipher.NewCFBDecrypter(block, iv)
 	stream.XORKeyStream(ciphertext, ciphertext)
 
+	if len(ciphertext) < len(magic) {
+		return nil, fmt.Errorf("ciphertext too short")
+	}
+
 	// Check if the decrypted data starts with the magic string
 	if string(ciphertext[:len(magic)]) != magic {
 		// A mismatch means the state was encrypted with a different passphrase,
diff --git a/app/controlplane/pkg/biz/attestationstate_test.go b/app/controlplane/pkg/biz/attestationstate_test.go
index bd243d29d..769006801 100644
--- a/app/controlplane/pkg/biz/attestationstate_test.go
+++ b/app/controlplane/pkg/biz/attestationstate_test.go
@@ -49,3 +49,34 @@ func TestErrInvalidPassphraseIsDiscoverableWhenWrapped(t *testing.T) {
 	wrapped := fmt.Errorf("failed to decrypt attestation state: %w", NewErrInvalidPassphrase())
 	assert.True(t, IsErrInvalidPassphrase(wrapped))
 }
+
+// Truncated stored values (salt + IV + fewer bytes than the magic prefix) must return an error, not panic.
+func TestDecryptShortInput(t *testing.T) {
+	testCases := []struct {
+		name string
+		size int
+	}{
+		{name: "salt and IV only", size: saltSize + 16},
+		{name: "one byte after IV", size: saltSize + 16 + 1},
+		{name: "one byte short of magic", size: saltSize + 16 + len(magic) - 1},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			var err error
+			require.NotPanics(t, func() {
+				_, err = decrypt(make([]byte, tc.size), "passphrase")
+			})
+			assert.Error(t, err)
+		})
+	}
+}
+
+func TestEncryptDecryptRoundTrip(t *testing.T) {
+	enc, err := encrypt([]byte("data"), "passphrase")
+	require.NoError(t, err)
+
+	got, err := decrypt(enc, "passphrase")
+	require.NoError(t, err)
+	assert.Equal(t, []byte("data"), got)
+}

From b30a8ac5a9bcfd6e0ae501c800447922c8b73ce4 Mon Sep 17 00:00:00 2001
From: Khanh Dinh Nguyen <77538987+beiryu@users.noreply.github.com>
Date: Thu, 15 Oct 2026 15:47:09 +0700
Subject: [PATCH 2/2] fix(controlplane): report short attestation state as
 invalid passphrase

A row too short to hold the magic prefix is a truncated or tampered value; report it like any other value that does not decrypt to the prefix, as the tampered-row integration test expects.

Signed-off-by: Khanh Dinh Nguyen <77538987+beiryu@users.noreply.github.com>
---
 app/controlplane/pkg/biz/attestationstate.go      | 4 +++-
 app/controlplane/pkg/biz/attestationstate_test.go | 2 +-
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/app/controlplane/pkg/biz/attestationstate.go b/app/controlplane/pkg/biz/attestationstate.go
index 7e3b4af8a..50276ef2d 100644
--- a/app/controlplane/pkg/biz/attestationstate.go
+++ b/app/controlplane/pkg/biz/attestationstate.go
@@ -272,8 +272,10 @@ func decrypt(ciphertext []byte, passphrase string) ([]byte, error) {
 	stream := cipher.NewCFBDecrypter(block, iv)
 	stream.XORKeyStream(ciphertext, ciphertext)
 
+	// Too short to hold the magic prefix: a truncated or tampered row, reported like
+	// any other value that does not decrypt to the magic prefix.
 	if len(ciphertext) < len(magic) {
-		return nil, fmt.Errorf("ciphertext too short")
+		return nil, NewErrInvalidPassphrase()
 	}
 
 	// Check if the decrypted data starts with the magic string
diff --git a/app/controlplane/pkg/biz/attestationstate_test.go b/app/controlplane/pkg/biz/attestationstate_test.go
index 769006801..b8c243ac6 100644
--- a/app/controlplane/pkg/biz/attestationstate_test.go
+++ b/app/controlplane/pkg/biz/attestationstate_test.go
@@ -67,7 +67,7 @@ func TestDecryptShortInput(t *testing.T) {
 			require.NotPanics(t, func() {
 				_, err = decrypt(make([]byte, tc.size), "passphrase")
 			})
-			assert.Error(t, err)
+			assert.True(t, IsErrInvalidPassphrase(err))
 		})
 	}
 }