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//===-- hwasan_interceptors.cpp -------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file is a part of HWAddressSanitizer.
//
// Interceptors for standard library functions.
//
// FIXME: move as many interceptors as possible into
// sanitizer_common/sanitizer_common_interceptors.h
//===----------------------------------------------------------------------===//
#include "interception/interception.h"
#include "hwasan.h"
#include "hwasan_thread.h"
#include "sanitizer_common/sanitizer_stackdepot.h"
#if !SANITIZER_FUCHSIA
using namespace __hwasan;
#if HWASAN_WITH_INTERCEPTORS
struct ThreadStartArg {
thread_callback_t callback;
void *param;
};
static void *HwasanThreadStartFunc(void *arg) {
__hwasan_thread_enter();
ThreadStartArg A = *reinterpret_cast<ThreadStartArg*>(arg);
UnmapOrDie(arg, GetPageSizeCached());
return A.callback(A.param);
}
INTERCEPTOR(int, pthread_create, void *th, void *attr, void *(*callback)(void*),
void * param) {
ScopedTaggingDisabler disabler;
ThreadStartArg *A = reinterpret_cast<ThreadStartArg *> (MmapOrDie(
GetPageSizeCached(), "pthread_create"));
*A = {callback, param};
int res = REAL(pthread_create)(th, attr, &HwasanThreadStartFunc, A);
return res;
}
DEFINE_REAL(int, vfork)
DECLARE_EXTERN_INTERCEPTOR_AND_WRAPPER(int, vfork)
#endif // HWASAN_WITH_INTERCEPTORS
#if HWASAN_WITH_INTERCEPTORS && defined(__aarch64__)
// Get and/or change the set of blocked signals.
extern "C" int sigprocmask(int __how, const __hw_sigset_t *__restrict __set,
__hw_sigset_t *__restrict __oset);
#define SIG_BLOCK 0
#define SIG_SETMASK 2
extern "C" int __sigjmp_save(__hw_sigjmp_buf env, int savemask) {
env[0].__mask_was_saved =
(savemask && sigprocmask(SIG_BLOCK, (__hw_sigset_t *)0,
&env[0].__saved_mask) == 0);
return 0;
}
static void __attribute__((always_inline))
InternalLongjmp(__hw_register_buf env, int retval) {
// Clear all memory tags on the stack between here and where we're going.
unsigned long long stack_pointer = env[13];
// The stack pointer should never be tagged, so we don't need to clear the
// tag for this function call.
__hwasan_handle_longjmp((void *)stack_pointer);
// Run code for handling a longjmp.
// Need to use a register that isn't going to be loaded from the environment
// buffer -- hence why we need to specify the register to use.
// Must implement this ourselves, since we don't know the order of registers
// in different libc implementations and many implementations mangle the
// stack pointer so we can't use it without knowing the demangling scheme.
register long int retval_tmp asm("x1") = retval;
register void *env_address asm("x0") = &env[0];
asm volatile("ldp x19, x20, [%0, #0<<3];"
"ldp x21, x22, [%0, #2<<3];"
"ldp x23, x24, [%0, #4<<3];"
"ldp x25, x26, [%0, #6<<3];"
"ldp x27, x28, [%0, #8<<3];"
"ldp x29, x30, [%0, #10<<3];"
"ldp d8, d9, [%0, #14<<3];"
"ldp d10, d11, [%0, #16<<3];"
"ldp d12, d13, [%0, #18<<3];"
"ldp d14, d15, [%0, #20<<3];"
"ldr x5, [%0, #13<<3];"
"mov sp, x5;"
// Return the value requested to return through arguments.
// This should be in x1 given what we requested above.
"cmp %1, #0;"
"mov x0, #1;"
"csel x0, %1, x0, ne;"
"br x30;"
: "+r"(env_address)
: "r"(retval_tmp));
}
INTERCEPTOR(void, siglongjmp, __hw_sigjmp_buf env, int val) {
if (env[0].__mask_was_saved)
// Restore the saved signal mask.
(void)sigprocmask(SIG_SETMASK, &env[0].__saved_mask,
(__hw_sigset_t *)0);
InternalLongjmp(env[0].__jmpbuf, val);
}
// Required since glibc libpthread calls __libc_longjmp on pthread_exit, and
// _setjmp on start_thread. Hence we have to intercept the longjmp on
// pthread_exit so the __hw_jmp_buf order matches.
INTERCEPTOR(void, __libc_longjmp, __hw_jmp_buf env, int val) {
InternalLongjmp(env[0].__jmpbuf, val);
}
INTERCEPTOR(void, longjmp, __hw_jmp_buf env, int val) {
InternalLongjmp(env[0].__jmpbuf, val);
}
#undef SIG_BLOCK
#undef SIG_SETMASK
#endif // HWASAN_WITH_INTERCEPTORS && __aarch64__
static void BeforeFork() {
StackDepotLockAll();
}
static void AfterFork() {
StackDepotUnlockAll();
}
INTERCEPTOR(int, fork, void) {
ENSURE_HWASAN_INITED();
BeforeFork();
int pid = REAL(fork)();
AfterFork();
return pid;
}
namespace __hwasan {
int OnExit() {
// FIXME: ask frontend whether we need to return failure.
return 0;
}
} // namespace __hwasan
namespace __hwasan {
void InitializeInterceptors() {
static int inited = 0;
CHECK_EQ(inited, 0);
INTERCEPT_FUNCTION(fork);
#if HWASAN_WITH_INTERCEPTORS
#if defined(__linux__)
INTERCEPT_FUNCTION(vfork);
#endif // __linux__
INTERCEPT_FUNCTION(pthread_create);
#endif
inited = 1;
}
} // namespace __hwasan
#endif // #if !SANITIZER_FUCHSIA
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