/*
* Copyright (c) 2023 Apple Computer, Inc. All rights reserved.
*
* @APPLE_OSREFERENCE_LICENSE_HEADER_START@
*
* This file contains Original Code and/or Modifications of Original Code
* as defined in and that are subject to the Apple Public Source License
* Version 2.0 (the 'License'). You may not use this file except in
* compliance with the License. The rights granted to you under the License
* may not be used to create, or enable the creation or redistribution of,
* unlawful or unlicensed copies of an Apple operating system, or to
* circumvent, violate, or enable the circumvention or violation of, any
* terms of an Apple operating system software license agreement.
*
* Please obtain a copy of the License at
* http://www.opensource.apple.com/apsl/ and read it before using this file.
*
* The Original Code and all software distributed under the License are
* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
* Please see the License for the specific language governing rights and
* limitations under the License.
*
* @APPLE_OSREFERENCE_LICENSE_HEADER_END@
*/
#include <darwintest.h>
#include <stdlib.h>
#include <unistd.h>
#include <mach/exception_types.h>
#include <sys/wait.h>
#include <sys/sysctl.h>
#include <sys/code_signing.h>
#include "exc_helpers.h"
#include "test_utils.h"
T_GLOBAL_META(
T_META_NAMESPACE("xnu.arm"),
T_META_RADAR_COMPONENT_NAME("xnu"),
T_META_RADAR_COMPONENT_VERSION("arm"),
T_META_OWNER("ghackmann"),
T_META_REQUIRES_SYSCTL_EQ("hw.optional.ptrauth", 1),
T_META_IGNORECRASHES(".*pac_exception_entitlement.*"),
XNU_T_META_SOC_SPECIFIC
);
#if __arm64e__
static size_t
exception_handler(mach_port_t task __unused, mach_port_t thread __unused,
exception_type_t type __unused, mach_exception_data_t codes __unused)
{
T_ASSERT_FAIL("kernel ran exception handler instead of terminating process");
}
/*
* Real-world software should use ptrauth.h when it needs to manually sign or
* auth pointers. But for testing purposes we need clang to emit specific
* ptrauth instructions, so we use inline asm here instead.
*
* Likewise clang would normally combine the "naked" auth and brk testcases as
* part of a sequence like:
*
* output = auth(...);
* if (output is poisoned) {
* brk(PTRAUTH_FAILURE_COMMENT);
* }
*
* On auth failure, CPUs that implement FEAT_FPAC will trap immediately at the
* auth instruction, and CPUs without FEAT_FPAC will trap at the later brk
* instruction. But again, for testing purposes we want these to be two
* discrete cases. (On FPAC-enabled CPUs, the kernel should treat *both* traps
* as ptrauth failure, even if we don't expect the latter to be reachable in
* real-world software.)
*/
static void
naked_auth(void)
{
asm volatile (
"mov x0, #0" "\n"
"paciza x0" "\n"
"eor x0, x0, (1 << 63)" "\n"
"autiza x0"
:
:
: "x0"
);
}
static void
ptrauth_brk(void)
{
asm volatile ("brk 0xc470");
}
static void
combined_branch_auth(void)
{
asm volatile (
"adr x0, 1f" "\n"
"paciza x0" "\n"
"eor x0, x0, (1 << 63)" "\n"
"braaz x0" "\n"
"1:"
:
:
: "x0"
);
}
static void
combined_load_auth(void)
{
asm volatile (
"mov x0, sp" "\n"
"pacdza x0" "\n"
"eor x0, x0, (1 << 63)" "\n"
"ldraa x0, [x0]" "\n"
:
:
: "x0"
);
}
static void
run_pac_exception_test(void (*ptrauth_failure_fn)(void))
{
pid_t pid = fork();
T_QUIET; T_ASSERT_POSIX_SUCCESS(pid, "fork");
if (pid == 0) {
mach_port_t exc_port = create_exception_port(EXC_MASK_BAD_ACCESS | EXC_MASK_BREAKPOINT);
run_exception_handler(exc_port, exception_handler);
ptrauth_failure_fn();
/* ptrauth_failure_fn() should have raised an uncatchable exception */
T_FAIL("child ran to completion");
} else {
int status;
int err = waitpid(pid, &status, 0);
T_QUIET; T_ASSERT_POSIX_SUCCESS(err, "waitpid");
T_EXPECT_TRUE(WIFSIGNALED(status), "child terminated due to signal");
T_EXPECT_EQ(SIGKILL, WTERMSIG(status), "child terminated due to SIGKILL");
}
}
#endif //__arm64e__
T_DECL(pac_exception_naked_auth,
"Test the com.apple.private.pac.exception entitlement (naked auth failure)",
T_META_REQUIRES_SYSCTL_EQ("hw.optional.arm.FEAT_FPAC", 1), T_META_TAG_VM_NOT_ELIGIBLE)
{
#if __arm64e__
run_pac_exception_test(naked_auth);
#else
T_SKIP("Running on non-arm64e target, skipping...");
#endif
}
T_DECL(pac_exception_ptrauth_brk,
"Test the com.apple.private.pac.exception entitlement (brk with comment indicating ptrauth failure)", T_META_TAG_VM_NOT_ELIGIBLE)
{
#if __arm64e__
run_pac_exception_test(ptrauth_brk);
#else
T_SKIP("Running on non-arm64e target, skipping...");
#endif
}
T_DECL(pac_exception_combined_branch_auth,
"Test the com.apple.private.pac.exception entitlement (combined branch + auth failure)", T_META_TAG_VM_NOT_ELIGIBLE)
{
#if __arm64e__
run_pac_exception_test(combined_branch_auth);
#else
T_SKIP("Running on non-arm64e target, skipping...");
#endif
}
T_DECL(pac_exception_combined_load_auth,
"Test the com.apple.private.pac.exception entitlement (combined branch + auth failure)", T_META_TAG_VM_NOT_ELIGIBLE)
{
#if __arm64e__
run_pac_exception_test(combined_load_auth);
#else
T_SKIP("Running on non-arm64e target, skipping...");
#endif
}