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Fix crash in StuffItX parser when block size overflows #189

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Fix crash in StuffItX parser when block size overflows #189

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954c459
Fix integer overflow in block size computation in XADStuffItXIronHandle
alek-prykhodko Jun 1, 2026
7493682
Add tests for block size overflow in XADStuffItXIronHandle
alek-prykhodko Jun 1, 2026
9fe60e4
Use portable overflow check in XADStuffItXIronHandle
alek-prykhodko Jun 1, 2026
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14 changes: 12 additions & 2 deletions XADStuffItXIronHandle.m
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Original file line number Diff line number Diff line change
Expand Up @@ -23,6 +23,7 @@
#import "StuffItXUtilities.h"
#import "CarrylessRangeCoder.h"
#import "BWT.h"
#import <limits.h>



Expand Down Expand Up @@ -93,12 +94,21 @@ -(int)produceBlockAtOffset:(off_t)pos

if(CSInputNextBitLE(input)==1) return -1;

unsigned int blocksize=(unsigned int)CSInputNextSitxP2(input);
uint64_t rawblocksize=CSInputNextSitxP2(input);
// Values above INT_MAX overflow when cast to int later (e.g. decodeBlockWithLength:).
if(rawblocksize>INT_MAX) [XADException raiseIllegalDataException];
unsigned int blocksize=(unsigned int)rawblocksize;
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if(blocksize>currsize)
{
size_t allocsize;
bool allocOverflowed=__builtin_mul_overflow((size_t)blocksize,(size_t)6,&allocsize);
if(allocOverflowed)
{
[XADException raiseIllegalDataException];
}
free(block);
block=malloc(blocksize*6);
block=malloc(allocsize);
if(!block) [XADException raiseOutOfMemoryException];
sorted=block+blocksize;
table=(uint32_t *)(block+2*blocksize);
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