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Fix accidental double-free in KJS garbage collector

This resolves Bug 2116
tags/r14.0.0
Timothy Pearson 5 years ago
parent
commit
36a7df39b0
1 changed files with 6 additions and 1 deletions
  1. 6
    1
      kjs/collector.cpp

+ 6
- 1
kjs/collector.cpp View File

@@ -24,6 +24,7 @@
#include "value.h"
#include "internal.h"
#include <limits.h>
#include <typeinfo>

#ifndef MAX
#define MAX(a,b) ((a) > (b) ? (a) : (b))
@@ -121,7 +122,7 @@ void* Collector::allocate(size_t s)

if (heap.usedBlocks == heap.numBlocks) {
static const size_t maxNumBlocks = ULONG_MAX / sizeof(CollectorBlock*) / GROWTH_FACTOR;
if (heap.numBlocks > maxNumBlocks)
if ((size_t)heap.numBlocks > maxNumBlocks)
return 0L;
heap.numBlocks = MAX(MIN_ARRAY_SIZE, heap.numBlocks * GROWTH_FACTOR);
heap.blocks = (CollectorBlock **)realloc(heap.blocks, heap.numBlocks * sizeof(CollectorBlock *));
@@ -222,6 +223,10 @@ bool Collector::collect()
if (!(imp->_flags & ValueImp::VI_DESTRUCTED)) {
if (!imp->refcount && imp->_flags == (ValueImp::VI_GCALLOWED | ValueImp::VI_CREATED)) {
//fprintf( stderr, "[kjs-collector] Collector::deleting ValueImp %p (%s)\n", (void*)imp, typeid(*imp).name());

// prevent double free
imp->_flags |= ValueImp::VI_DESTRUCTED;

// emulate destructing part of 'operator delete()'
imp->~ValueImp();
curBlock->usedCells--;

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