Re: [Nbd] BUG: oversized 64b offset wrap not detected when offset + len > 64bit and thus wraps

[folkert <folkert@...421...>]

[regarding ssize_t]

> printf("%d\n", sizeof(ssize_t));
> says 8 bytes on a 64b system
> 
> On a 32b system that (((ssize_t)((off_t)request.from + len) >
> client->exportsize)) indeed fails dramatically.
> So my fix was not complete :-)

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

int main(int argc, char *argv[])
{
        uint64_t bla = 10ll * 1024ll *1024ll *1024ll; // will definately overflow on 32b (10GB)
        uint32_t bla2 = bla;

        printf("%lld\n", (ssize_t)((off_t)bla));
        printf("%u\n", bla2);

        printf("%d\n", sizeof(ssize_t));

        return 0;
}

folkert@...1279... /tmp $ ./a.out 
-9223372036854741816
2147483648
4

mauer:/usr/local# ./a.out 
10737418240
2147483648
8


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