fix: use the Network Name spare-bit count for PNN GSM-7 text (v2.7.21)

EF.PNN decoded 'Miranda@' for the live card's record 2: efPnnText ignored
the number of spare bits in the coding octet (TS 24.008 10.5.3.5a bits
1-3) and unpacked floor(8n/7) septets, so the 7 zero pad bits became '@'.

- gsm7Decode(octets, septets?) takes an exact character count and removes
  a final <CR> used as padding (TS 23.038 6.1.2.1.1).
- efPnnText derives the count from the spare field ((8n - spare)/7 when
  1-7; floor(8n/7) + CR drop for 000 = no information).
- tests: the seven live EF.PNN records (Alfa, Miranda, Win, Mir Telekom,
  +7 Telekom, Fenix, MKS), a UCS2 record and the CR-padding drop.
- docs/uicc/UICC_SPECS.md: CR-padding rule in 10.4 and a new 10.7
  Network Name coding section (outside the repo).

frontend/index.html

@@ -1414,7 +1414,7 @@
 // ===== Version =====
 // Single source of truth for the PWA version: shown in the header and used
 // by the server version check in pysimConnect().
-const SIMPLE_VERSION = '2.7.20';
+const SIMPLE_VERSION = '2.7.21';
 document.getElementById('app-version').textContent = 'v' + SIMPLE_VERSION;
 
 // ===== Tab switching =====
@@ -3767,16 +3767,22 @@ function decodePrivileges(hex) {
 	return parts.join(', ') || 'None';
 }
 
-function gsm7Decode(octets) {
+// GSM 03.38 7-bit unpacking.  `septets` (optional) is the exact character
+// count — the Network Name coding carries the number of spare bits, so the
+// zero padding must not decode as a trailing '@'.  A final <CR> used as
+// padding (TS 23.038 6.1.2.1.1) is removed when the count is known.
+function gsm7Decode(octets, septets) {
 	const bits = [];
 	for (const b of octets) {
 		for (let j = 0; j < 8; j++) bits.push((b >> j) & 1);
 	}
+	const max = Math.floor(bits.length / 7);
+	const count = septets === undefined ? max : Math.min(septets, max);
 	let out = '';
 	let escape = false;
-	for (let i = 0; i + 7 <= bits.length; i += 7) {
+	for (let i = 0; i < count; i++) {
 		let septet = 0;
-		for (let j = 0; j < 7; j++) septet |= bits[i + j] << j;
+		for (let j = 0; j < 7; j++) septet |= bits[i * 7 + j] << j;
 		if (escape) {
 			const ext = Object.entries(GSM7_EXT_MAP).find(([,v]) => v === septet);
 			out += ext ? ext[0] : '?';
@@ -3787,6 +3793,7 @@ function gsm7Decode(octets) {
 			out += septet < GSM7_ALPHABET.length ? GSM7_ALPHABET[septet] : '?';
 		}
 	}
+	if (septets !== undefined && out.endsWith('\r')) out = out.slice(0, -1);
 	return out;
 }
 
@@ -12058,10 +12065,15 @@ function efPlmnAct(u16) {
 }
 
 // TS 23.038 Network Name (DCS byte + text) from EF_PNN.
+// TS 24.008 10.5.3.5a Network Name (the EF.PNN 43/45 TLV value): the first
+// byte is the coding octet — bit 8 ext, bits 5-7 coding scheme (000 GSM
+// 7-bit, 001 UCS2), bit 4 Add CI, bits 1-3 the number of spare bits in the
+// last octet (the value is the count, 1-7; 000 = no information).
 function efPnnText(value) {
 	if (value.length < 2) return '';
 	const dcs = value[0];
 	const coding = (dcs >> 4) & 0x07;
+	const spare = dcs & 0x07;
 	let data = efRstripFf(value.subarray(1));
 	if (coding === 1) {
 		for (let i = 0; i + 1 < data.length; i += 2) {
@@ -12072,7 +12084,11 @@ function efPnnText(value) {
 	if (coding === 0) {
 		let allLow = data.length > 0;
 		for (let i = 0; i < data.length; i++) if (data[i] >= 0x80) { allLow = false; break; }
-		return allLow ? efGsm7Octets(data) : gsm7Decode(data);
+		if (allLow) return efGsm7Octets(data);
+		const nbits = data.length * 8;
+		const septets = spare > 0 ? Math.floor((nbits - spare) / 7)
+			: Math.floor(nbits / 7);
+		return gsm7Decode(data, septets);
 	}
 	return '';
 }

frontend/sw.js

@@ -1,4 +1,4 @@
-const CACHE = 'simple-v223';
+const CACHE = 'simple-v224';
 const URLS = [
   'index.html',
   'help.html',

frontend/tests/ef_decode.test.js

@@ -73,6 +73,28 @@ test('efAnnexA decodes GSM7 octets, UCS2 and packed variants', () => {
 	assert.strictEqual(efAnnexA(efBytes('FFFFFFFF')), '');
 });
 
+test('efPnnText uses the spare-bit count (TS 24.008 10.5.3.5a)', () => {
+	// Live card EF.PNN records: coding octet + packed GSM-7 text.  The spare
+	// bits in the coding octet give the exact character count, so the zero
+	// padding must not decode as a trailing '@' (record 2 was 'Miranda@').
+	const cases = [
+		['8441b6390c', 'Alfa'],
+		['87cdb43cec268701', 'Miranda'],
+		['83d7b41b', 'Win'],
+		['83cdb41c442db3cbeb771b', 'Mir Telekom'],
+		['82ab1b885a6697d7ef36', '+7 Telekom'],
+		['85c6b23b8d07', 'Fenix'],
+		['83cde514', 'MKS'],
+	];
+	for (const [hex, text] of cases) {
+		assert.strictEqual(efPnnText(efBytes(hex)), text, hex);
+	}
+	// UCS2 coding scheme (octet 3 bits 5-7 = 001)
+	assert.strictEqual(efPnnText(efBytes('91004d006900720061006e00640061')), 'Miranda');
+	// a final <CR> used as padding is removed (TS 23.038 6.1.2.1.1)
+	assert.strictEqual(gsm7Decode(efBytes('cdb43cec26871b'), 8), 'Miranda');
+});
+
 test('EF decoders match the pinned spec / pySim test vectors', () => {
 	assert.deepStrictEqual(efDecIccid(efBytes('988812010000400310f0')), { iccid: '8988211000000430010' });
 	assert.deepStrictEqual(efDecImsi(efBytes('082982608200002080')), { imsi: '228062800000208' });

pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "pysim-simple-server"
-version = "2.7.20"
+version = "2.7.21"
 description = "HTTP REST server wrapping pysim for the SIMple PWA"
 requires-python = ">=3.8"
 # pysim is a git-only dependency installed explicitly by setup.bat/setup.sh.

pysim_simple_server/server.py

@@ -26,7 +26,7 @@ from osmocom.tlv import BER_TLV_IE
 from osmocom.utils import rpad
 
 
-VERSION = '2.7.20'
+VERSION = '2.7.21'
 
 MAX_ENVELOPE_SEGMENTS = 5  # max SMS segments for outgoing C-APDU in ENVELOPE