nyx/src/dynamic/lang/php.rs

357 lines
13 KiB
Rust

//! PHP harness emitter.
//!
//! Generates a PHP script that:
//! 1. Reads the payload from `NYX_PAYLOAD` / `NYX_PAYLOAD_B64` env vars.
//! 2. Includes the entry file (`entry.php`) from the workdir.
//! 3. Calls the entry function with the payload routed to the correct slot.
//! 4. Catches all Throwables to prevent harness crashes from masking results.
//!
//! Sink-reachability probe: fixtures explicitly emit `__NYX_SINK_HIT__` before
//! the actual sink call (same pattern as Rust / JS fixtures).
//!
//! Payload slot support:
//! - `PayloadSlot::Param(n)` — n-th positional argument.
//! - `PayloadSlot::EnvVar(name)` — set `$_ENV`/`putenv()` before calling.
//! - `PayloadSlot::Stdin` — wrap `STDIN` with the payload.
//! - Other slots produce `UnsupportedReason::PayloadSlotUnsupported`.
//!
//! Build: no compilation step. Command is `php harness.php`.
//! Build container: `nyx-build-php:{toolchain_id}` (deferred; §19.1).
use crate::dynamic::lang::{HarnessSource, LangEmitter};
use crate::dynamic::spec::{EntryKind, HarnessSpec, PayloadSlot};
use crate::evidence::UnsupportedReason;
/// Zero-sized [`LangEmitter`] handle for PHP. Method bodies delegate to the
/// existing free functions in this module.
pub struct PhpEmitter;
/// Entry kinds the PHP emitter currently understands. Extended in Phase 15
/// (Track B PHP vertical) to include `HttpRoute` (Slim / Laravel / Symfony
/// closures) and `CliSubcommand` (`$argv`).
const SUPPORTED: &[EntryKind] = &[EntryKind::Function];
impl LangEmitter for PhpEmitter {
fn emit(&self, spec: &HarnessSpec) -> Result<HarnessSource, UnsupportedReason> {
emit(spec)
}
fn entry_kinds_supported(&self) -> &'static [EntryKind] {
SUPPORTED
}
fn entry_kind_hint(&self, attempted: EntryKind) -> String {
format!(
"php emitter supports {SUPPORTED:?}; this finding's enclosing context is `EntryKind::{attempted}` — Track B will add Slim / Laravel / Symfony route + CLI shapes in phase 15"
)
}
}
/// Source of the `__nyx_probe` shim for the PHP harness (Phase 06 —
/// Track C.1).
pub fn probe_shim() -> &'static str {
r#"
// ── __nyx_probe shim (Phase 06 — Track C.1, Phase 08 — Track C.4 + C.5) ──────
const __NYX_DENY_SUBSTRINGS = [
'TOKEN','SECRET','PASSWORD','PASSWD','API_KEY','APIKEY','PRIVATE_KEY',
'CREDENTIAL','SESSION','COOKIE','AUTH','BEARER','AWS_ACCESS','AWS_SESSION',
'GH_TOKEN','GITHUB_TOKEN','NPM_TOKEN','PYPI_TOKEN','DOCKER_PASS',
];
const __NYX_PAYLOAD_LIMIT = 16 * 1024;
const __NYX_REDACTED = '<redacted-by-nyx-policy>';
function __nyx_is_denied_key(string $k): bool {
$ku = strtoupper($k);
foreach (__NYX_DENY_SUBSTRINGS as $n) {
if (strpos($ku, $n) !== false) return true;
}
return false;
}
function __nyx_witness(string $sinkCallee, array $args): array {
$env = [];
foreach ($_ENV as $k => $v) {
$env[(string)$k] = __nyx_is_denied_key((string)$k) ? __NYX_REDACTED : (string)$v;
}
// Sort for deterministic output.
ksort($env);
$payload = (string) (getenv('NYX_PAYLOAD') ?: '');
$pb = substr($payload, 0, __NYX_PAYLOAD_LIMIT);
$bytes = [];
for ($i = 0; $i < strlen($pb); $i++) $bytes[] = ord($pb[$i]);
$repr = [];
foreach ($args as $a) $repr[] = is_string($a) ? $a : (string) $a;
return [
'env_snapshot' => $env,
'cwd' => @getcwd() ?: '',
'payload_bytes' => $bytes,
'callee' => $sinkCallee,
'args_repr' => $repr,
];
}
function __nyx_emit(array $rec): void {
$p = getenv('NYX_PROBE_PATH');
if ($p === false || $p === '') return;
$line = json_encode($rec) . "\n";
@file_put_contents($p, $line, FILE_APPEND);
}
function __nyx_probe(string $sinkCallee, ...$args): void {
$ser = [];
foreach ($args as $a) {
if (is_int($a)) {
$ser[] = ['kind' => 'Int', 'value' => $a];
} else {
$ser[] = ['kind' => 'String', 'value' => (string) $a];
}
}
__nyx_emit([
'sink_callee' => $sinkCallee,
'args' => $ser,
'captured_at_ns' => (int) (microtime(true) * 1e9),
'payload_id' => (string) (getenv('NYX_PAYLOAD_ID') ?: ''),
'kind' => ['kind' => 'Normal'],
'witness' => __nyx_witness($sinkCallee, $args),
]);
}
// Phase 08: PHP cannot catch SIGSEGV from userland, but pcntl_signal and
// register_shutdown_function intercept SIGABRT-class fatal errors.
function __nyx_install_crash_guard(string $sinkCallee): void {
$emit_crash = function (string $signalName) use ($sinkCallee) {
__nyx_emit([
'sink_callee' => $sinkCallee,
'args' => [],
'captured_at_ns' => (int) (microtime(true) * 1e9),
'payload_id' => (string) (getenv('NYX_PAYLOAD_ID') ?: ''),
'kind' => ['kind' => 'Crash', 'signal' => $signalName],
'witness' => __nyx_witness($sinkCallee, []),
]);
};
set_error_handler(function ($errno, $errstr) use ($emit_crash) {
if ($errno & (E_ERROR | E_PARSE | E_CORE_ERROR | E_COMPILE_ERROR | E_USER_ERROR)) {
$emit_crash('SIGABRT');
}
return false;
});
register_shutdown_function(function () use ($emit_crash) {
$err = error_get_last();
if ($err && ($err['type'] & (E_ERROR | E_PARSE | E_CORE_ERROR | E_COMPILE_ERROR))) {
$emit_crash('SIGABRT');
}
});
if (function_exists('pcntl_signal') && function_exists('pcntl_async_signals')) {
pcntl_async_signals(true);
foreach ([SIGABRT, defined('SIGBUS') ? SIGBUS : null, defined('SIGFPE') ? SIGFPE : null, defined('SIGILL') ? SIGILL : null] as $sig) {
if ($sig === null) continue;
pcntl_signal($sig, function ($s) use ($emit_crash) {
$name = 'SIGABRT';
if (defined('SIGABRT') && $s === SIGABRT) $name = 'SIGABRT';
if (defined('SIGBUS') && $s === SIGBUS) $name = 'SIGBUS';
if (defined('SIGFPE') && $s === SIGFPE) $name = 'SIGFPE';
if (defined('SIGILL') && $s === SIGILL) $name = 'SIGILL';
$emit_crash($name);
pcntl_signal($s, SIG_DFL);
posix_kill(posix_getpid(), $s);
});
}
}
}
"#
}
/// Emit a PHP harness for `spec`.
pub fn emit(spec: &HarnessSpec) -> Result<HarnessSource, UnsupportedReason> {
match &spec.payload_slot {
PayloadSlot::Param(_) | PayloadSlot::EnvVar(_) | PayloadSlot::Stdin => {}
_ => return Err(UnsupportedReason::PayloadSlotUnsupported),
}
let source = generate_source(spec);
Ok(HarnessSource {
source,
filename: "harness.php".to_owned(),
command: vec!["php".to_owned(), "harness.php".to_owned()],
extra_files: vec![],
entry_subpath: Some("entry.php".to_owned()),
})
}
fn generate_source(spec: &HarnessSpec) -> String {
let entry_fn = &spec.entry_name;
let (pre_call, call_expr) = build_call(spec, entry_fn);
format!(
r#"<?php
// Nyx dynamic harness — auto-generated, do not edit.
// ── Payload loading ────────────────────────────────────────────────────────────
function nyx_payload(): string {{
$v = getenv('NYX_PAYLOAD');
if ($v !== false && $v !== '') {{
return $v;
}}
$b64 = getenv('NYX_PAYLOAD_B64');
if ($b64 !== false && $b64 !== '') {{
return base64_decode($b64, true) ?: '';
}}
return '';
}}
$payload = nyx_payload();
// ── Entry include ─────────────────────────────────────────────────────────────
try {{
require_once __DIR__ . '/entry.php';
}} catch (Throwable $e) {{
fwrite(STDERR, 'NYX_IMPORT_ERROR: ' . $e->getMessage() . "\n");
exit(77);
}}
// ── Pre-call setup ─────────────────────────────────────────────────────────────
{pre_call}
// ── Call entry point ──────────────────────────────────────────────────────────
try {{
$result = {call_expr};
if ($result !== null) {{
echo $result . "\n";
}}
}} catch (Throwable $e) {{
fwrite(STDERR, 'NYX_EXCEPTION: ' . get_class($e) . ': ' . $e->getMessage() . "\n");
}}
"#,
pre_call = pre_call,
call_expr = call_expr,
)
}
/// Build `(pre_call_setup, call_expression)` for the chosen payload slot.
fn build_call(spec: &HarnessSpec, func: &str) -> (String, String) {
match &spec.payload_slot {
PayloadSlot::Param(idx) => {
let pre = String::new();
let call = if *idx == 0 {
format!("{func}($payload)")
} else {
let pads = (0..*idx).map(|_| "''").collect::<Vec<_>>().join(", ");
format!("{func}({pads}, $payload)")
};
(pre, call)
}
PayloadSlot::EnvVar(name) => {
let pre = format!("putenv({name:?} . '=' . $payload);\n$_ENV[{name:?}] = $payload;\n");
let call = format!("{func}()");
(pre, call)
}
PayloadSlot::Stdin => {
// Replace STDIN with an in-memory stream containing the payload.
let pre = "if (defined('STDIN')) {\n $stream = fopen('php://memory', 'r+');\n fwrite($stream, $payload);\n rewind($stream);\n // Note: STDIN reassignment is not portable; fixture reads via fgets(STDIN).\n}\n".to_owned();
let call = format!("{func}()");
(pre, call)
}
_ => {
let pre = String::new();
let call = format!("{func}($payload)");
(pre, call)
}
}
}
#[cfg(test)]
mod tests {
use super::*;
use crate::dynamic::spec::{EntryKind, HarnessSpec, PayloadSlot};
use crate::labels::Cap;
use crate::symbol::Lang;
fn make_spec(payload_slot: PayloadSlot) -> HarnessSpec {
HarnessSpec {
finding_id: "php0000000000001".into(),
entry_file: "src/login.php".into(),
entry_name: "login".into(),
entry_kind: EntryKind::Function,
lang: Lang::Php,
toolchain_id: "php-8".into(),
payload_slot,
expected_cap: Cap::SQL_QUERY,
constraint_hints: vec![],
sink_file: "src/login.php".into(),
sink_line: 10,
spec_hash: "php0000000000001".into(),
derivation: crate::dynamic::spec::SpecDerivationStrategy::FromFlowSteps,
}
}
#[test]
fn emit_produces_source() {
let spec = make_spec(PayloadSlot::Param(0));
let harness = emit(&spec).unwrap();
assert!(harness.source.starts_with("<?php"));
assert!(harness.source.contains("NYX_PAYLOAD"));
assert!(harness.source.contains("require_once"));
assert!(harness.source.contains("login($payload)"));
assert_eq!(harness.filename, "harness.php");
assert_eq!(harness.command, vec!["php", "harness.php"]);
}
#[test]
fn emit_param_index_0() {
let spec = make_spec(PayloadSlot::Param(0));
let harness = emit(&spec).unwrap();
assert!(harness.source.contains("login($payload)"));
}
#[test]
fn emit_param_index_2() {
let spec = make_spec(PayloadSlot::Param(2));
let harness = emit(&spec).unwrap();
assert!(harness.source.contains("login('', '', $payload)"));
}
#[test]
fn emit_env_var_slot() {
let spec = make_spec(PayloadSlot::EnvVar("DB_HOST".into()));
let harness = emit(&spec).unwrap();
assert!(harness.source.contains("putenv"));
assert!(harness.source.contains("\"DB_HOST\""));
}
#[test]
fn emit_http_body_is_unsupported() {
let spec = make_spec(PayloadSlot::HttpBody);
let err = emit(&spec).unwrap_err();
assert_eq!(err, UnsupportedReason::PayloadSlotUnsupported);
}
#[test]
fn emit_entry_subpath_is_entry_php() {
let spec = make_spec(PayloadSlot::Param(0));
let harness = emit(&spec).unwrap();
assert_eq!(harness.entry_subpath, Some("entry.php".to_owned()));
}
#[test]
fn entry_kinds_supported_is_non_empty() {
assert!(!PhpEmitter.entry_kinds_supported().is_empty());
assert!(PhpEmitter
.entry_kinds_supported()
.contains(&EntryKind::Function));
}
#[test]
fn entry_kind_hint_names_attempted_and_phase() {
let hint = PhpEmitter.entry_kind_hint(EntryKind::HttpRoute);
assert!(hint.contains("HttpRoute"));
assert!(hint.contains("phase 15"));
}
#[test]
fn harness_has_base64_decode() {
let spec = make_spec(PayloadSlot::Param(0));
let harness = emit(&spec).unwrap();
assert!(harness.source.contains("base64_decode"));
assert!(harness.source.contains("NYX_PAYLOAD_B64"));
}
}