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#include <assert.h>
#include "pauth.h"
static int x;
int main()
{
int *p0 = &x, *p1, *p2, *p3;
unsigned long salt = 0;
int pac_feature = get_pac_feature();
/*
* Exit if no PAuth or FEAT_FPAC, which will SIGILL on AUTDA failure
* rather than return an error for us to check below.
*/
if (pac_feature == 0 || pac_feature >= 4) {
return 0;
}
/*
* With TBI enabled and a 48-bit VA, there are 7 bits of auth, and so
* a 1/128 chance of auth = pac(ptr,key,salt) producing zero.
* Find a salt that creates auth != 0.
*/
do {
salt++;
asm("pacda %0, %1" : "=r"(p1) : "r"(salt), "0"(p0));
} while (p0 == p1);
/*
* This pac must fail, because the input pointer bears an encryption,
* and so is not properly extended within bits [55:47]. This will
* toggle bit 54 in the output...
*/
asm("pacda %0, %1" : "=r"(p2) : "r"(salt), "0"(p1));
/* ... so that the aut must fail, setting bit 53 in the output ... */
asm("autda %0, %1" : "=r"(p3) : "r"(salt), "0"(p2));
/* ... which means this equality must not hold. */
assert(p3 != p0);
return 0;
}
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