59 lines
1.7 KiB
C
59 lines
1.7 KiB
C
#include <stdint.h>
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#include <assert.h>
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void do_test(uint64_t value)
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{
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uint64_t salt1, salt2;
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uint64_t encode, decode;
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/*
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* With TBI enabled and a 48-bit VA, there are 7 bits of auth,
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* and so a 1/128 chance of encode = pac(value,key,salt) producing
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* an auth for which leaves value unchanged.
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* Iterate until we find a salt for which encode != value.
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*/
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for (salt1 = 1; ; salt1++) {
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asm volatile("pacda %0, %2" : "=r"(encode) : "0"(value), "r"(salt1));
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if (encode != value) {
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break;
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}
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}
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/* A valid salt must produce a valid authorization. */
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asm volatile("autda %0, %2" : "=r"(decode) : "0"(encode), "r"(salt1));
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assert(decode == value);
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/*
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* An invalid salt usually fails authorization, but again there
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* is a chance of choosing another salt that works.
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* Iterate until we find another salt which does fail.
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*/
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for (salt2 = salt1 + 1; ; salt2++) {
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asm volatile("autda %0, %2" : "=r"(decode) : "0"(encode), "r"(salt2));
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if (decode != value) {
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break;
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}
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}
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/* The VA bits, bit 55, and the TBI bits, should be unchanged. */
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assert(((decode ^ value) & 0xff80ffffffffffffull) == 0);
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/*
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* Bits [54:53] are an error indicator based on the key used;
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* the DA key above is keynumber 0, so error == 0b01. Otherwise
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* bit 55 of the original is sign-extended into the rest of the auth.
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*/
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if ((value >> 55) & 1) {
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assert(((decode >> 48) & 0xff) == 0b10111111);
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} else {
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assert(((decode >> 48) & 0xff) == 0b00100000);
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}
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}
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int main()
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{
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do_test(0);
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do_test(-1);
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do_test(0xda004acedeadbeefull);
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return 0;
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}
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