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// Copyright 2016 syzkaller project authors. All rights reserved.
// Use of this source code is governed by Apache 2 LICENSE that can be found in the LICENSE file.
// This file is shared between executor and csource package.
#include <stdint.h>
#include <string.h>
#if defined(SYZ_EXECUTOR) || defined(SYZ_THREADED) || defined(SYZ_COLLIDE)
#include <pthread.h>
#include <stdlib.h>
#endif
#if defined(SYZ_EXECUTOR) || defined(SYZ_USE_TMP_DIR)
#include <errno.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/stat.h>
#endif
#if defined(SYZ_EXECUTOR) || defined(SYZ_HANDLE_SEGV)
#include <setjmp.h>
#include <signal.h>
#include <string.h>
#endif
#if defined(SYZ_EXECUTOR) || (defined(SYZ_REPEAT) && defined(SYZ_WAIT_REPEAT))
#include <errno.h>
#include <signal.h>
#include <stdarg.h>
#include <stdio.h>
#include <sys/time.h>
#include <sys/wait.h>
#include <time.h>
#endif
#if defined(SYZ_EXECUTOR) || defined(SYZ_DEBUG)
#include <stdarg.h>
#include <stdio.h>
#endif
#if defined(SYZ_EXECUTOR)
typedef long (*syscall_t)(long, long, long, long, long, long, long, long, long);
struct call_t {
const char* name;
int sys_nr;
syscall_t call;
};
// Defined in generated syscalls_OS.h files.
extern call_t syscalls[];
extern unsigned syscall_count;
#endif
#if defined(SYZ_EXECUTOR) || (defined(SYZ_REPEAT) && defined(SYZ_WAIT_REPEAT)) || \
defined(SYZ_USE_TMP_DIR) || defined(SYZ_TUN_ENABLE) || defined(SYZ_SANDBOX_NAMESPACE) || \
defined(SYZ_SANDBOX_SETUID) || defined(SYZ_FAULT_INJECTION) || defined(__NR_syz_kvm_setup_cpu)
const int kFailStatus = 67;
const int kRetryStatus = 69;
#endif
#if defined(SYZ_EXECUTOR)
const int kErrorStatus = 68;
#endif
#if defined(SYZ_EXECUTOR) || (defined(SYZ_REPEAT) && defined(SYZ_WAIT_REPEAT)) || \
defined(SYZ_USE_TMP_DIR) || defined(SYZ_TUN_ENABLE) || defined(SYZ_SANDBOX_NAMESPACE) || \
defined(SYZ_SANDBOX_SETUID) || defined(SYZ_FAULT_INJECTION) || defined(__NR_syz_kvm_setup_cpu)
// logical error (e.g. invalid input program), use as an assert() alernative
__attribute__((noreturn)) static void fail(const char* msg, ...)
{
int e = errno;
fflush(stdout);
va_list args;
va_start(args, msg);
vfprintf(stderr, msg, args);
va_end(args);
fprintf(stderr, " (errno %d)\n", e);
// ENOMEM/EAGAIN is frequent cause of failures in fuzzing context,
// so handle it here as non-fatal error.
doexit((e == ENOMEM || e == EAGAIN) ? kRetryStatus : kFailStatus);
}
#endif
#if defined(SYZ_EXECUTOR)
// kernel error (e.g. wrong syscall return value)
__attribute__((noreturn)) static void error(const char* msg, ...)
{
fflush(stdout);
va_list args;
va_start(args, msg);
vfprintf(stderr, msg, args);
va_end(args);
fprintf(stderr, "\n");
doexit(kErrorStatus);
}
#endif
#if defined(SYZ_EXECUTOR) || (defined(SYZ_REPEAT) && defined(SYZ_WAIT_REPEAT))
// just exit (e.g. due to temporal ENOMEM error)
__attribute__((noreturn)) static void exitf(const char* msg, ...)
{
int e = errno;
fflush(stdout);
va_list args;
va_start(args, msg);
vfprintf(stderr, msg, args);
va_end(args);
fprintf(stderr, " (errno %d)\n", e);
doexit(kRetryStatus);
}
#endif
#if defined(SYZ_EXECUTOR) || defined(SYZ_DEBUG)
static int flag_debug;
static void debug(const char* msg, ...)
{
if (!flag_debug)
return;
va_list args;
va_start(args, msg);
vfprintf(stdout, msg, args);
va_end(args);
fflush(stdout);
}
#endif
#if defined(SYZ_EXECUTOR) || defined(SYZ_USE_BITMASKS)
#define BITMASK_LEN(type, bf_len) (type)((1ull << (bf_len)) - 1)
#define BITMASK_LEN_OFF(type, bf_off, bf_len) (type)(BITMASK_LEN(type, (bf_len)) << (bf_off))
#define STORE_BY_BITMASK(type, addr, val, bf_off, bf_len) \
if ((bf_off) == 0 && (bf_len) == 0) { \
*(type*)(addr) = (type)(val); \
} else { \
type new_val = *(type*)(addr); \
new_val &= ~BITMASK_LEN_OFF(type, (bf_off), (bf_len)); \
new_val |= ((type)(val)&BITMASK_LEN(type, (bf_len))) << (bf_off); \
*(type*)(addr) = new_val; \
}
#endif
#if defined(SYZ_EXECUTOR) || defined(SYZ_HANDLE_SEGV)
static __thread int skip_segv;
static __thread jmp_buf segv_env;
static void segv_handler(int sig, siginfo_t* info, void* uctx)
{
// Generated programs can contain bad (unmapped/protected) addresses,
// which cause SIGSEGVs during copyin/copyout.
// This handler ignores such crashes to allow the program to proceed.
// We additionally opportunistically check that the faulty address
// is not within executable data region, because such accesses can corrupt
// output region and then fuzzer will fail on corrupted data.
uintptr_t addr = (uintptr_t)info->si_addr;
const uintptr_t prog_start = 1 << 20;
const uintptr_t prog_end = 100 << 20;
if (__atomic_load_n(&skip_segv, __ATOMIC_RELAXED) && (addr < prog_start || addr > prog_end)) {
debug("SIGSEGV on %p, skipping\n", addr);
_longjmp(segv_env, 1);
}
debug("SIGSEGV on %p, exiting\n", addr);
doexit(sig);
for (;;) {
}
}
#define NONFAILING(...) \
{ \
__atomic_fetch_add(&skip_segv, 1, __ATOMIC_SEQ_CST); \
if (_setjmp(segv_env) == 0) { \
__VA_ARGS__; \
} \
__atomic_fetch_sub(&skip_segv, 1, __ATOMIC_SEQ_CST); \
}
#endif
#if defined(SYZ_EXECUTOR) || defined(SYZ_USE_CHECKSUMS)
struct csum_inet {
uint32_t acc;
};
static void csum_inet_init(struct csum_inet* csum)
{
csum->acc = 0;
}
static void csum_inet_update(struct csum_inet* csum, const uint8_t* data, size_t length)
{
if (length == 0)
return;
size_t i;
for (i = 0; i < length - 1; i += 2)
csum->acc += *(uint16_t*)&data[i];
if (length & 1)
csum->acc += (uint16_t)data[length - 1];
while (csum->acc > 0xffff)
csum->acc = (csum->acc & 0xffff) + (csum->acc >> 16);
}
static uint16_t csum_inet_digest(struct csum_inet* csum)
{
return ~csum->acc;
}
#endif
#if defined(SYZ_EXECUTOR) || (defined(SYZ_REPEAT) && defined(SYZ_WAIT_REPEAT))
static uint64_t current_time_ms()
{
struct timespec ts;
if (clock_gettime(CLOCK_MONOTONIC, &ts))
fail("clock_gettime failed");
return (uint64_t)ts.tv_sec * 1000 + (uint64_t)ts.tv_nsec / 1000000;
}
#endif
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