CODEWITHSUNDEEP
swiftbuffer-overflowaddress-sanitizer
Dan Beaulieu
Dan Beaulieu

Reputation: 19954

How do I create a buffer overflow to test Address Sanitizer?

Problem

I'm attempting to create a buffer overflow in order to learn more about Address Sanitizer. I've written the following code which I thought would create a buffer overflow, though I must be mistaken as it's not throwing the expected "Heap buffer overflow detected".

Attempt 

    var ints : [UInt8] = [ 1, 2, 3, 4 ]

    let a = UnsafeMutableBufferPointer(start: &ints, count: ints.count)

    a[28] = 17 // array out of index

I've enabled Address Sanitizer in Xcode by clicking my application > Edit Scheme... and then "Enable Address Sanitizer". Then I rebuilt my application before running.

Question

How do I create a buffer overflow in Swift 2?

Upvotes: 2

Views: 1278

Answers (1)

Martin R
Martin R

Reputation: 539975

From https://developer.apple.com/videos/play/wwdc2015-413/?time=947

Address Sanitizer is an LLVM tool for C-based languages.

and https://developer.apple.com/videos/play/wwdc2015-413/?time=1422

In order to use Address Sanitizer, Xcode passes a special flag to clang.

It seems that the Address Sanitizer is only available with clang for C, Objective-C etc., but not with the Swift compiler swiftc.

A simple C program which triggers a buffer overflow is

#include <stdio.h>
#include <stdlib.h>

int main(int argc, const char * argv[]) {

    int *p = malloc(4 * sizeof(int));
    p[28] = 17;

    return 0;
}

Upvotes: 4

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