871a7f6a9a
With FEAT_FPAC, AUT* instructions that fail authentication do not produce an error value but instead fault. For pauth-2, install a signal handler and verify it gets called. For pauth-4 and pauth-5, we are explicitly testing the error value, so there's nothing to test with FEAT_FPAC, so exit early. Adjust the makefile to use -cpu neoverse-v1, which has FEAT_EPAC but not FEAT_FPAC. Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org> Message-id: 20230829232335.965414-2-richard.henderson@linaro.org Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
97 lines
2.5 KiB
C
97 lines
2.5 KiB
C
#include <stdint.h>
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#include <signal.h>
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#include <stdlib.h>
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#include <assert.h>
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#include "pauth.h"
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static void sigill(int sig, siginfo_t *info, void *vuc)
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{
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ucontext_t *uc = vuc;
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uint64_t test;
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/* There is only one insn below that is allowed to fault. */
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asm volatile("adr %0, auth2_insn" : "=r"(test));
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assert(test == uc->uc_mcontext.pc);
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exit(0);
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}
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static int pac_feature;
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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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* With FEAT_FPAC, this will SIGILL instead of producing a result.
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*/
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for (salt2 = salt1 + 1; ; salt2++) {
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asm volatile("auth2_insn: autda %0, %2"
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: "=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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assert(pac_feature < 4); /* No FEAT_FPAC */
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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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* Without FEAT_Pauth2, bits [54:53] are an error indicator based on
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* the key used; the DA key above is keynumber 0, so error == 0b01.
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* Otherwise, bit 55 of the original is sign-extended into the rest
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* of the auth.
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*/
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if (pac_feature < 3) {
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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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}
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int main()
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{
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static const struct sigaction sa = {
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.sa_sigaction = sigill,
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.sa_flags = SA_SIGINFO
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};
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pac_feature = get_pac_feature();
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assert(pac_feature != 0);
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if (pac_feature >= 4) {
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/* FEAT_FPAC */
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sigaction(SIGILL, &sa, NULL);
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}
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do_test(0);
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do_test(0xda004acedeadbeefull);
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return 0;
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}
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