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fix(runtime): bound all crash-handler formatting (review finding from #86) #87

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Merged
CoreyRDean merged 1 commit into from
Jun 9, 2026
Merged

fix(runtime): bound all crash-handler formatting (review finding from #86) #87

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40 changes: 27 additions & 13 deletions src/blitzrc/bbruntime_dll/bbruntime_dll.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -77,7 +77,7 @@ static string symbolName( void *addr ){
DWORD64 disp=0;
if( pSymFromAddr( GetCurrentProcess(),(DWORD64)(uintptr_t)addr,&disp,sym ) ){
char out[320];
sprintf( out," (%s+0x%X)",sym->Name,(unsigned int)disp );
snprintf( out,sizeof(out)," (%s+0x%X)",sym->Name,(unsigned int)disp );
return out;
}
return "";
Expand All @@ -96,11 +96,11 @@ static string describeAddress( void *addr ){
if( n ){
const char *base=path;
for( const char *p=path;*p;++p ) if( *p=='\\'||*p=='/' ) base=p+1;
sprintf( buf,"%s+0x%X",base,(unsigned int)((char*)addr-(char*)mbi.AllocationBase) );
snprintf( buf,sizeof(buf),"%s+0x%X",base,(unsigned int)((char*)addr-(char*)mbi.AllocationBase) );
return string( buf )+symbolName( addr );
}
}
sprintf( buf,"0x%p",addr );
snprintf( buf,sizeof(buf),"0x%p",addr );
return buf;
}

Expand Down Expand Up @@ -130,14 +130,18 @@ static void _cdecl seTranslator( unsigned int u,EXCEPTION_POINTERS* pExp ){
// describeAddress allocates stack, and the guard page is already blown.
if( pExp && pExp->ExceptionRecord && u!=EXCEPTION_STACK_OVERFLOW ){
EXCEPTION_RECORD *er=pExp->ExceptionRecord;
char info[96];
sprintf( info," [code 0x%08X at ",(unsigned int)er->ExceptionCode );
// Scratch must hold the longest line: the regs dump is 110 chars
// + NUL. Format exclusively through snprintf(sizeof) so the crash
// handler can never corrupt its own stack frame (review finding:
// the first revision sprintf'd 111 bytes into a 96-byte buffer).
char info[160];
snprintf( info,sizeof(info)," [code 0x%08X at ",(unsigned int)er->ExceptionCode );
panicStr+=info;
panicStr+=describeAddress( er->ExceptionAddress );
if( u==EXCEPTION_ACCESS_VIOLATION && er->NumberParameters>=2 ){
const char *kind=er->ExceptionInformation[0]==0 ? "reading" :
(er->ExceptionInformation[0]==1 ? "writing" : "executing");
sprintf( info,", %s 0x%08X",kind,(unsigned int)er->ExceptionInformation[1] );
snprintf( info,sizeof(info),", %s 0x%08X",kind,(unsigned int)er->ExceptionInformation[1] );
panicStr+=info;
}
panicStr+="]";
Expand All @@ -152,11 +156,11 @@ static void _cdecl seTranslator( unsigned int u,EXCEPTION_POINTERS* pExp ){
if( ip && VirtualQuery( ip,&mbi,sizeof(mbi) ) && mbi.State==MEM_COMMIT ){
panicStr+="\ncode:";
for( int k=0;k<16;++k ){
sprintf( info," %02X",ip[k] );
snprintf( info,sizeof(info)," %02X",ip[k] );
panicStr+=info;
}
}
sprintf( info,"\nregs: eax=%08X ebx=%08X ecx=%08X edx=%08X esi=%08X edi=%08X esp=%08X ebp=%08X",
snprintf( info,sizeof(info),"\nregs: eax=%08X ebx=%08X ecx=%08X edx=%08X esi=%08X edi=%08X esp=%08X ebp=%08X",
(unsigned)cx->Eax,(unsigned)cx->Ebx,(unsigned)cx->Ecx,(unsigned)cx->Edx,
(unsigned)cx->Esi,(unsigned)cx->Edi,(unsigned)cx->Esp,(unsigned)cx->Ebp );
panicStr+=info;
Expand All @@ -169,12 +173,22 @@ static void _cdecl seTranslator( unsigned int u,EXCEPTION_POINTERS* pExp ){
if( !GetModuleFileName( (HMODULE)mbi.AllocationBase,path,MAX_PATH ) ){
unsigned char *base=(unsigned char*)mbi.AllocationBase;
unsigned int len=0x280;
sprintf( info,"\nimage @0x%p (fault offset 0x%X):",base,(unsigned int)(ip-base) );
panicStr+=info;
for( unsigned int k=0;k<len;++k ){
if( (k&15)==0 ){ sprintf( info,"\n%04X:",k ); panicStr+=info; }
sprintf( info," %02X",base[k] );
// Bound the dump to the committed region that actually
// contains the allocation base -- it can differ from the
// region containing the faulting IP, and a nested fault
// inside the handler would truncate the whole panic.
MEMORY_BASIC_INFORMATION mbiDump;
if( VirtualQuery( base,&mbiDump,sizeof(mbiDump) ) && mbiDump.State==MEM_COMMIT
&& !(mbiDump.Protect&(PAGE_GUARD|PAGE_NOACCESS)) ){
unsigned int avail=(unsigned int)((char*)mbiDump.BaseAddress+mbiDump.RegionSize-(char*)base);
if( len>avail ) len=avail;
snprintf( info,sizeof(info),"\nimage @0x%p (fault offset 0x%X):",base,(unsigned int)(ip-base) );
panicStr+=info;
for( unsigned int k=0;k<len;++k ){
if( (k&15)==0 ){ snprintf( info,sizeof(info),"\n%04X:",k ); panicStr+=info; }
snprintf( info,sizeof(info)," %02X",base[k] );
panicStr+=info;
}
}
}
}
Expand Down
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