DVX_GUI/src/apps/kpunch/dvxbasic/compiler/obfuscate.c

633 lines
20 KiB
C

// The MIT License (MIT)
//
// Copyright (C) 2026 Scott Duensing
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to
// deal in the Software without restriction, including without limitation the
// rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
// sell copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
// IN THE SOFTWARE.
// obfuscate.c -- Release build name obfuscation
//
// See obfuscate.h for the high-level description.
#include "obfuscate.h"
#include "basEvents.h"
#include "lexer.h"
#include "../basRes.h"
#include "../runtime/values.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define BAS_OBF_TOKEN_LEN BAS_MAX_IDENT // longest form/control/type token kept from a .frm line
#define BAS_OBF_MAPPED_LEN 16 // "C" + decimal index + NUL
#define BAS_OBF_MAP_INIT_CAP 16 // initial name-map capacity (doubles on growth)
#define BAS_REM_KEYWORD_LEN 3 // "REM"
// ============================================================
// Name map
// ============================================================
typedef struct {
char *orig; // original name (strdup'd, case-preserved)
char *mapped; // new name (strdup'd, "C1" .. "Cn")
} NameEntryT;
typedef struct {
NameEntryT *entries;
int32_t count;
int32_t cap;
} NameMapT;
// Function prototypes (alphabetical)
void basObfuscateNames(BasModuleT *mod, const char **frmTexts, const int32_t *frmLens, int32_t frmCount, BasObfFrmT *outFrms);
int32_t basStripFrmComments(const char *src, int32_t srcLen, uint8_t *outBuf, int32_t outCap);
static void collectNamesFromFrm(const char *text, int32_t len, NameMapT *names, NameMapT *reserved);
static void emitBytes(uint8_t *out, int32_t outCap, int32_t *outLen, const char *src, int32_t len);
static const char *nameMapAdd(NameMapT *m, const char *name);
static void nameMapFree(NameMapT *m);
static void nameMapInit(NameMapT *m);
static const char *nameMapLookup(const NameMapT *m, const char *name);
static const char *readToken(const char *p, const char *end, char *buf, int32_t bufSize);
static void replaceConstant(BasModuleT *mod, int32_t idx, const char *newText);
static int32_t rewriteFrmText(const char *src, int32_t srcLen, const NameMapT *map, uint8_t *out, int32_t outCap);
static void rewriteModuleConstants(BasModuleT *mod, const NameMapT *map);
static void rewriteModuleFormVars(BasModuleT *mod, const NameMapT *map);
static void rewriteModuleProcs(BasModuleT *mod, const NameMapT *map);
static const char *skipWhitespace(const char *p, const char *end);
// ============================================================
// Top-level entry point
// ============================================================
void basObfuscateNames(BasModuleT *mod, const char **frmTexts, const int32_t *frmLens, int32_t frmCount, BasObfFrmT *outFrms) {
if (!mod || frmCount < 0) {
return;
}
// Pass 1: collect all names from all .frm texts. A control whose name
// is also a control type or a property key (a TextBox named "Text", a
// Timer named "Timer") is left alone: the constant pool cannot tell a
// name reference apart from the identically spelled property/type name
// used by OP_LOAD_PROP and friends.
NameMapT names;
NameMapT reserved;
NameMapT map;
nameMapInit(&names);
nameMapInit(&reserved);
nameMapInit(&map);
for (int32_t i = 0; i < frmCount; i++) {
if (frmTexts[i] && frmLens[i] > 0) {
collectNamesFromFrm(frmTexts[i], frmLens[i], &names, &reserved);
}
}
for (int32_t i = 0; i < names.count; i++) {
if (!nameMapLookup(&reserved, names.entries[i].orig)) {
nameMapAdd(&map, names.entries[i].orig);
}
}
nameMapFree(&names);
nameMapFree(&reserved);
// Pass 2: rewrite each .frm, sized by a measuring pass so a form with
// many short names that grow ("a" -> "C12") can never be truncated.
for (int32_t i = 0; i < frmCount; i++) {
outFrms[i].data = NULL;
outFrms[i].len = 0;
if (!frmTexts[i] || frmLens[i] <= 0) {
continue;
}
int32_t strippedLen = basFindFormEndPos(frmTexts[i], frmLens[i]);
int32_t outCap = rewriteFrmText(frmTexts[i], strippedLen, &map, NULL, 0) + 1;
uint8_t *outBuf = malloc(outCap);
if (!outBuf) {
continue;
}
int32_t outLen = rewriteFrmText(frmTexts[i], strippedLen, &map, outBuf, outCap);
// Ensure trailing newline
if (outLen > 0 && outBuf[outLen - 1] != '\n') {
outBuf[outLen++] = '\n';
}
outFrms[i].data = outBuf;
outFrms[i].len = outLen;
}
// Pass 3: rewrite module
rewriteModuleConstants(mod, &map);
rewriteModuleProcs(mod, &map);
rewriteModuleFormVars(mod, &map);
nameMapFree(&map);
}
int32_t basStripFrmComments(const char *src, int32_t srcLen, uint8_t *outBuf, int32_t outCap) {
if (!src || srcLen <= 0 || !outBuf || outCap <= 0) {
return 0;
}
int32_t outLen = 0;
int32_t i = 0;
while (i < srcLen) {
int32_t lineStart = i;
while (i < srcLen && src[i] != '\n' && src[i] != '\r') {
i++;
}
int32_t lineEnd = i;
if (i < srcLen && src[i] == '\r') {
i++;
}
if (i < srcLen && src[i] == '\n') {
i++;
}
// Scan for first unquoted ' (comment start).
bool inStr = false;
int32_t commentStart = -1;
for (int32_t j = lineStart; j < lineEnd; j++) {
char c = src[j];
if (c == '"') {
inStr = !inStr;
} else if (c == '\'' && !inStr) {
commentStart = j;
break;
}
}
int32_t contentEnd = (commentStart >= 0) ? commentStart : lineEnd;
// Check for whole-line REM. Find first non-whitespace position.
int32_t firstNonWs = lineStart;
while (firstNonWs < contentEnd && (src[firstNonWs] == ' ' || src[firstNonWs] == '\t')) {
firstNonWs++;
}
if (contentEnd - firstNonWs >= BAS_REM_KEYWORD_LEN &&
strncasecmp(src + firstNonWs, "REM", BAS_REM_KEYWORD_LEN) == 0 &&
(contentEnd - firstNonWs == BAS_REM_KEYWORD_LEN ||
src[firstNonWs + BAS_REM_KEYWORD_LEN] == ' ' ||
src[firstNonWs + BAS_REM_KEYWORD_LEN] == '\t')) {
contentEnd = firstNonWs;
}
// Trim trailing whitespace.
while (contentEnd > lineStart && (src[contentEnd - 1] == ' ' || src[contentEnd - 1] == '\t')) {
contentEnd--;
}
// Drop lines that have no non-whitespace content.
if (contentEnd <= firstNonWs) {
continue;
}
// Strip leading whitespace -- the form parser trims per line
// anyway, so shipping indentation just bloats the embedded resource.
int32_t writeLen = contentEnd - firstNonWs;
if (outLen + writeLen + 1 >= outCap) {
break;
}
memcpy(outBuf + outLen, src + firstNonWs, writeLen);
outLen += writeLen;
outBuf[outLen++] = '\n';
}
return outLen;
}
// ============================================================
// Pass 1: collect form/control names and the identifiers they must not
// collide with
// ============================================================
// Scan a .frm text: every "Begin <Type> <Name>" adds Name to names, and
// Type plus every "<Key> = ..." property key goes into reserved.
static void collectNamesFromFrm(const char *text, int32_t len, NameMapT *names, NameMapT *reserved) {
const char *p = text;
const char *end = text + len;
while (p < end) {
// Read one line
const char *lineStart = p;
while (p < end && *p != '\n' && *p != '\r') {
p++;
}
const char *lineEnd = p;
if (p < end && *p == '\r') {
p++;
}
if (p < end && *p == '\n') {
p++;
}
// Trim leading whitespace
const char *l = skipWhitespace(lineStart, lineEnd);
char token[BAS_OBF_TOKEN_LEN];
if ((lineEnd - l) >= BAS_BEGIN_PREFIX_LEN && strncasecmp(l, "Begin ", BAS_BEGIN_PREFIX_LEN) == 0) {
l = skipWhitespace(l + BAS_BEGIN_PREFIX_LEN, lineEnd);
l = readToken(l, lineEnd, token, sizeof(token));
if (token[0] == '\0') {
continue;
}
nameMapAdd(reserved, token);
l = skipWhitespace(l, lineEnd);
readToken(l, lineEnd, token, sizeof(token));
if (token[0] && basIsValidIdent(token)) {
nameMapAdd(names, token);
}
continue;
}
// "<Key> = value": the key is a property name.
l = readToken(l, lineEnd, token, sizeof(token));
l = skipWhitespace(l, lineEnd);
if (l < lineEnd && *l == '=' && token[0] && basIsValidIdent(token)) {
nameMapAdd(reserved, token);
}
}
}
// ============================================================
// Pass 2: rewrite .frm text with mapped names
// ============================================================
// Appends len bytes of src to out (bounded by outCap) and always advances
// *outLen, so a NULL out measures the exact output size.
static void emitBytes(uint8_t *out, int32_t outCap, int32_t *outLen, const char *src, int32_t len) {
if (out && *outLen + len <= outCap) {
memcpy(out + *outLen, src, len);
}
*outLen += len;
}
// Returns true if c is a valid identifier character.
static const char *nameMapAdd(NameMapT *m, const char *name) {
const char *existing = nameMapLookup(m, name);
if (existing) {
return existing;
}
if (m->count >= m->cap) {
int32_t newCap = m->cap == 0 ? BAS_OBF_MAP_INIT_CAP : m->cap * 2;
NameEntryT *newEntries = realloc(m->entries, newCap * sizeof(NameEntryT));
if (!newEntries) {
return NULL;
}
m->entries = newEntries;
m->cap = newCap;
}
char mapped[BAS_OBF_MAPPED_LEN];
snprintf(mapped, sizeof(mapped), "C%ld", (long)(m->count + 1));
m->entries[m->count].orig = strdup(name);
m->entries[m->count].mapped = strdup(mapped);
m->count++;
return m->entries[m->count - 1].mapped;
}
static void nameMapFree(NameMapT *m) {
for (int32_t i = 0; i < m->count; i++) {
free(m->entries[i].orig);
free(m->entries[i].mapped);
}
free(m->entries);
m->entries = NULL;
m->count = 0;
m->cap = 0;
}
static void nameMapInit(NameMapT *m) {
m->entries = NULL;
m->count = 0;
m->cap = 0;
}
// Look up an original name (case-insensitive). Returns mapped name or NULL.
static const char *nameMapLookup(const NameMapT *m, const char *name) {
for (int32_t i = 0; i < m->count; i++) {
if (strcasecmp(m->entries[i].orig, name) == 0) {
return m->entries[i].mapped;
}
}
return NULL;
}
// Copy next whitespace-delimited token into buf. Returns pointer after token.
static const char *readToken(const char *p, const char *end, char *buf, int32_t bufSize) {
int32_t len = 0;
while (p < end && *p != ' ' && *p != '\t' && *p != '\r' && *p != '\n' && len < bufSize - 1) {
buf[len++] = *p++;
}
buf[len] = '\0';
return p;
}
// ============================================================
// Module rewriting
// ============================================================
// Replace the contents of a constant pool entry with a new string.
static void replaceConstant(BasModuleT *mod, int32_t idx, const char *newText) {
BasStringT *newStr = basStringNew(newText, (int32_t)strlen(newText));
if (!newStr) {
return;
}
basStringUnref(mod->constants[idx]);
mod->constants[idx] = newStr;
}
// Rewrites the .frm text line by line. Only positions that hold a
// form/control NAME are remapped: the name token of a "Begin <Type> <Name>"
// line and a property value that is exactly a mapped name (bare, or the
// whole content of a quoted string such as DataSource = "datCat"). Type
// tokens and property keys are copied verbatim. Identifiers of any length
// are copied from the source span, never through a fixed buffer. With out
// NULL nothing is written and the return value is the required size.
static int32_t rewriteFrmText(const char *src, int32_t srcLen, const NameMapT *map, uint8_t *out, int32_t outCap) {
int32_t outLen = 0;
const char *p = src;
const char *end = src + srcLen;
while (p < end) {
const char *lineStart = p;
while (p < end && *p != '\n' && *p != '\r') {
p++;
}
const char *lineEnd = p;
if (p < end && *p == '\r') {
p++;
}
if (p < end && *p == '\n') {
p++;
}
const char *l = skipWhitespace(lineStart, lineEnd);
const char *replaceStart = NULL; // span of the original name to swap
const char *replaceEnd = NULL;
const char *mapped = NULL;
char token[BAS_OBF_TOKEN_LEN];
if ((lineEnd - l) >= BAS_BEGIN_PREFIX_LEN && strncasecmp(l, "Begin ", BAS_BEGIN_PREFIX_LEN) == 0) {
// Begin <Type> <Name>: only the name token is a candidate.
const char *t = skipWhitespace(l + BAS_BEGIN_PREFIX_LEN, lineEnd);
t = readToken(t, lineEnd, token, sizeof(token));
t = skipWhitespace(t, lineEnd);
const char *nameStart = t;
t = readToken(t, lineEnd, token, sizeof(token));
if (token[0] && t - nameStart == (int32_t)strlen(token)) {
mapped = nameMapLookup(map, token);
replaceStart = nameStart;
replaceEnd = t;
}
} else {
// <Key> = value: a value that is exactly a mapped name (bare or
// quoted) refers to a control and follows the rename.
const char *t = readToken(l, lineEnd, token, sizeof(token));
t = skipWhitespace(t, lineEnd);
if (t < lineEnd && *t == '=') {
t = skipWhitespace(t + 1, lineEnd);
const char *valueStart = t;
const char *valueEnd = lineEnd;
while (valueEnd > valueStart && (valueEnd[-1] == ' ' || valueEnd[-1] == '\t')) {
valueEnd--;
}
if (valueEnd - valueStart >= 2 && *valueStart == '"' && valueEnd[-1] == '"') {
valueStart++;
valueEnd--;
}
int32_t valueLen = (int32_t)(valueEnd - valueStart);
bool isIdent = (valueLen > 0 && valueLen < (int32_t)sizeof(token));
for (int32_t k = 0; isIdent && k < valueLen; k++) {
isIdent = basIsIdentChar(valueStart[k]);
}
if (isIdent) {
memcpy(token, valueStart, valueLen);
token[valueLen] = '\0';
mapped = nameMapLookup(map, token);
replaceStart = valueStart;
replaceEnd = valueEnd;
}
}
}
if (mapped) {
emitBytes(out, outCap, &outLen, lineStart, (int32_t)(replaceStart - lineStart));
emitBytes(out, outCap, &outLen, mapped, (int32_t)strlen(mapped));
emitBytes(out, outCap, &outLen, replaceEnd, (int32_t)(p - replaceEnd));
} else {
emitBytes(out, outCap, &outLen, lineStart, (int32_t)(p - lineStart));
}
}
return outLen;
}
static void rewriteModuleConstants(BasModuleT *mod, const NameMapT *map) {
// KNOWN LIMITATION: the constant pool dedupes a plain string literal and a
// same-text control/form-name reference into ONE entry, so a release build
// that does e.g. MsgBox "Save" while also having a control named "Save"
// will see that literal rewritten to the obfuscated name ("C5"). Fully
// separating name references from literals would give name refs their own
// pool slots and change emitted bytecode for every release build, so it is
// deferred; avoid string literals that exactly match a control/form name
// in release builds. Names that collide with a property key or control
// type are never mapped at all (see basObfuscateNames).
for (int32_t i = 0; i < mod->constCount; i++) {
const BasStringT *s = mod->constants[i];
if (!s) {
continue;
}
const char *mapped = nameMapLookup(map, s->data);
if (mapped) {
replaceConstant(mod, i, mapped);
continue;
}
// "<Name>_<Event>" handler names used as SetEvent targets follow the
// procedure rename so basModuleFindProc still resolves them.
const char *underscore = strrchr(s->data, '_');
if (!underscore || !basEventSuffixMatch(underscore + 1)) {
continue;
}
int32_t prefixLen = (int32_t)(underscore - s->data);
char prefix[BAS_MAX_IDENT];
if (prefixLen >= (int32_t)sizeof(prefix)) {
continue;
}
memcpy(prefix, s->data, prefixLen);
prefix[prefixLen] = '\0';
mapped = nameMapLookup(map, prefix);
if (mapped) {
char newName[BAS_MAX_IDENT];
snprintf(newName, sizeof(newName), "%s_%s", mapped, underscore + 1);
replaceConstant(mod, i, newName);
}
}
}
static void rewriteModuleFormVars(BasModuleT *mod, const NameMapT *map) {
for (int32_t i = 0; i < mod->formVarInfoCount; i++) {
BasFormVarInfoT *fv = &mod->formVarInfo[i];
const char *mapped = nameMapLookup(map, fv->formName);
if (mapped) {
snprintf(fv->formName, sizeof(fv->formName), "%s", mapped);
}
}
}
static void rewriteModuleProcs(BasModuleT *mod, const NameMapT *map) {
for (int32_t i = 0; i < mod->procCount; i++) {
BasProcEntryT *proc = &mod->procs[i];
if (proc->name[0] == '\0') {
continue;
}
// Remap the owning form name (used at runtime to bind form-scope
// variables). The form itself gets renamed by the same pass.
if (proc->formName[0]) {
const char *mappedForm = nameMapLookup(map, proc->formName);
if (mappedForm) {
snprintf(proc->formName, sizeof(proc->formName), "%s", mappedForm);
}
}
// Find last underscore
char *underscore = strrchr(proc->name, '_');
if (!underscore) {
continue;
}
const char *suffix = underscore + 1;
if (!basEventSuffixMatch(suffix)) {
continue;
}
// Split on underscore
int32_t prefixLen = (int32_t)(underscore - proc->name);
char prefix[BAS_MAX_IDENT];
if (prefixLen >= (int32_t)sizeof(prefix)) {
prefixLen = (int32_t)sizeof(prefix) - 1;
}
memcpy(prefix, proc->name, prefixLen);
prefix[prefixLen] = '\0';
const char *mapped = nameMapLookup(map, prefix);
if (mapped) {
char newName[BAS_MAX_IDENT];
snprintf(newName, sizeof(newName), "%s_%s", mapped, suffix);
snprintf(proc->name, sizeof(proc->name), "%s", newName);
}
}
}
// ============================================================
// .frm parsing helpers
// ============================================================
// Skip ASCII whitespace. Returns pointer past whitespace.
static const char *skipWhitespace(const char *p, const char *end) {
while (p < end && (*p == ' ' || *p == '\t')) {
p++;
}
return p;
}