#include "sandbox/linux/seccomp-bpf-helpers/sigsys_handlers.h"
#include <fcntl.h>
#include <linux/net.h>
#include <stddef.h>
#include <stdint.h>
#include <string.h>
#include <sys/syscall.h>
#include <unistd.h>
#include "base/check.h"
#include "base/compiler_specific.h"
#include "base/debug/crash_logging.h"
#include "base/posix/eintr_wrapper.h"
#include "base/strings/safe_sprintf.h"
#include "build/build_config.h"
#include "sandbox/linux/bpf_dsl/bpf_dsl.h"
#include "sandbox/linux/seccomp-bpf/sandbox_bpf.h"
#include "sandbox/linux/seccomp-bpf/syscall.h"
#include "sandbox/linux/services/syscall_wrappers.h"
#include "sandbox/linux/system_headers/linux_seccomp.h"
#include "sandbox/linux/system_headers/linux_stat.h"
#include "sandbox/linux/system_headers/linux_syscalls.h"
#if BUILDFLAG(IS_ANDROID)
#include <android/log.h>
#endif
#if defined(__mips__)
#include <asm/unistd.h>
#endif
#define SECCOMP_MESSAGE_COMMON_CONTENT "seccomp-bpf failure"
#define SECCOMP_MESSAGE_CLONE_CONTENT "clone() failure"
#define SECCOMP_MESSAGE_PRCTL_CONTENT "prctl() failure"
#define SECCOMP_MESSAGE_IOCTL_CONTENT "ioctl() failure"
#define SECCOMP_MESSAGE_KILL_CONTENT "(tg)kill() failure"
#define SECCOMP_MESSAGE_FUTEX_CONTENT "futex() failure"
#define SECCOMP_MESSAGE_PTRACE_CONTENT "ptrace() failure"
#define SECCOMP_MESSAGE_SOCKET_CONTENT "socket() failure"
#define SECCOMP_MESSAGE_SOCKOPT_CONTENT "*sockopt() failure"
namespace {
#if BUILDFLAG(IS_ANDROID)
constexpr char kLogTag[] = "cr_seccomp";
#endif
base::debug::CrashKeyString* seccomp_crash_key = nullptr;
base::debug::CrashKeyString* seccomp_ioctl_crash_key = nullptr;
inline bool IsArchitectureX86_64() {
#if defined(__x86_64__)
return true;
#else
return false;
#endif
}
void WriteToStdErr(const char* error_message, size_t size) {
#if BUILDFLAG(IS_ANDROID)
__android_log_write(ANDROID_LOG_ERROR, kLogTag, error_message);
#endif
while (size > 0) {
const int ret = HANDLE_EINTR(
sandbox::sys_write(STDERR_FILENO, error_message, size));
if (ret <= 0 || static_cast<size_t>(ret) > size) {
break;
}
size -= ret;
UNSAFE_TODO(error_message += ret);
}
}
uint32_t SyscallNumberToOffsetFromBase(uint32_t sysno) {
#if defined(__mips__)
sysno = sysno - __NR_Linux;
#endif
if (sysno >= 1024)
sysno = 0;
return sysno;
}
void PrintAndSetSeccompCrashKey(const struct arch_seccomp_data& args) {
char crash_key[256];
size_t crash_key_length = base::strings::SafeSPrintf(
crash_key, "nr=0x%x arg1=0x%x arg2=0x%x arg3=0x%x arg4=0x%x", args.nr,
args.args[0], args.args[1], args.args[2], args.args[3]);
base::debug::SetCrashKeyString(seccomp_crash_key, crash_key);
#if defined(ARCH_CPU_MIPS_FAMILY) && defined(ARCH_CPU_32_BITS)
static constexpr char kSeccompError[] =
__FILE__ ":**CRASHING**:" SECCOMP_MESSAGE_COMMON_CONTENT
" in syscall (base 4000) ";
#else
static constexpr char kSeccompError[] =
__FILE__ ":**CRASHING**:" SECCOMP_MESSAGE_COMMON_CONTENT " in syscall ";
#endif
WriteToStdErr(kSeccompError, sizeof(kSeccompError) - 1);
WriteToStdErr(crash_key, crash_key_length);
#if !BUILDFLAG(IS_ANDROID)
WriteToStdErr("\n", 1);
#endif
}
}
namespace sandbox {
intptr_t CrashSIGSYS_Handler(const struct arch_seccomp_data& args, void* aux) {
uint32_t syscall = SyscallNumberToOffsetFromBase(args.nr);
PrintAndSetSeccompCrashKey(args);
syscall |= ((args.args[0] & 0xffUL) << 12);
syscall |= ((args.args[1] & 0xffUL) << 20);
volatile char* addr = reinterpret_cast<volatile char*>(syscall);
*addr = '\0';
syscall &= 0xfffUL;
addr = reinterpret_cast<volatile char*>(syscall);
*addr = '\0';
for (;;)
_exit(1);
}
intptr_t SIGSYSCloneFailure(const struct arch_seccomp_data& args, void* aux) {
static constexpr char kSeccompCloneError[] =
__FILE__ ":**CRASHING**:" SECCOMP_MESSAGE_CLONE_CONTENT "\n";
WriteToStdErr(kSeccompCloneError, sizeof(kSeccompCloneError) - 1);
PrintAndSetSeccompCrashKey(args);
volatile uint64_t clone_flags = args.args[0];
volatile char* addr;
if (IsArchitectureX86_64()) {
addr = reinterpret_cast<volatile char*>(clone_flags & 0xFFFFFF);
*addr = '\0';
}
addr = reinterpret_cast<volatile char*>(clone_flags & 0xFFF);
*addr = '\0';
for (;;)
_exit(1);
}
intptr_t SIGSYSPrctlFailure(const struct arch_seccomp_data& args,
void* ) {
static constexpr char kSeccompPrctlError[] =
__FILE__ ":**CRASHING**:" SECCOMP_MESSAGE_PRCTL_CONTENT "\n";
WriteToStdErr(kSeccompPrctlError, sizeof(kSeccompPrctlError) - 1);
PrintAndSetSeccompCrashKey(args);
volatile uint64_t option = args.args[0];
volatile char* addr =
reinterpret_cast<volatile char*>(option & 0xFFF);
*addr = '\0';
for (;;)
_exit(1);
}
intptr_t SIGSYSIoctlFailure(const struct arch_seccomp_data& args,
void* ) {
static constexpr char kSeccompIoctlError[] =
__FILE__ ":**CRASHING**:" SECCOMP_MESSAGE_IOCTL_CONTENT "\n";
WriteToStdErr(kSeccompIoctlError, sizeof(kSeccompIoctlError) - 1);
PrintAndSetSeccompCrashKey(args);
char message[256];
size_t message_len;
default_stat_struct stat_buf;
const int fstat_ret =
syscall(__NR_fstat_default, static_cast<int>(args.args[0]), &stat_buf);
if (fstat_ret == 0) {
MSAN_UNPOISON(&stat_buf, sizeof(stat_buf));
message_len = base::strings::SafeSPrintf(
message,
"dev=0x%x,ino=%d,mode=0%o,nlink=%d,"
"uid=%d,gid=%d,rdev=0x%x,size=%d,blksize=%d,blocks=%d",
stat_buf.st_dev, stat_buf.st_ino, stat_buf.st_mode, stat_buf.st_nlink,
stat_buf.st_uid, stat_buf.st_gid, stat_buf.st_rdev, stat_buf.st_size,
stat_buf.st_blksize, stat_buf.st_blocks);
} else {
message_len = base::strings::SafeSPrintf(message, "fstat failed, errno=%d",
-fstat_ret);
}
WriteToStdErr(message, message_len);
base::debug::SetCrashKeyString(seccomp_ioctl_crash_key, message);
volatile uint64_t request = args.args[1];
volatile char* addr = reinterpret_cast<volatile char*>(request & 0xFFFF);
*addr = '\0';
addr = reinterpret_cast<volatile char*>(request & 0xFFF);
*addr = '\0';
for (;;)
_exit(1);
}
intptr_t SIGSYSKillFailure(const struct arch_seccomp_data& args,
void* ) {
static constexpr char kSeccompKillError[] =
__FILE__ ":**CRASHING**:" SECCOMP_MESSAGE_KILL_CONTENT "\n";
WriteToStdErr(kSeccompKillError, sizeof(kSeccompKillError) - 1);
PrintAndSetSeccompCrashKey(args);
volatile uint64_t my_pid = sys_getpid();
volatile char* addr = reinterpret_cast<volatile char*>(my_pid & 0xFFF);
*addr = '\0';
for (;;)
_exit(1);
}
intptr_t SIGSYSFutexFailure(const struct arch_seccomp_data& args,
void* ) {
static constexpr char kSeccompFutexError[] =
__FILE__ ":**CRASHING**:" SECCOMP_MESSAGE_FUTEX_CONTENT "\n";
WriteToStdErr(kSeccompFutexError, sizeof(kSeccompFutexError) - 1);
PrintAndSetSeccompCrashKey(args);
volatile int futex_op = args.args[1];
volatile char* addr = reinterpret_cast<volatile char*>(futex_op & 0xFFF);
*addr = '\0';
for (;;)
_exit(1);
}
intptr_t SIGSYSPtraceFailure(const struct arch_seccomp_data& args,
void* ) {
static constexpr char kSeccompPtraceError[] =
__FILE__ ":**CRASHING**:" SECCOMP_MESSAGE_PTRACE_CONTENT "\n";
WriteToStdErr(kSeccompPtraceError, sizeof(kSeccompPtraceError) - 1);
PrintAndSetSeccompCrashKey(args);
volatile int ptrace_op = args.args[0];
volatile char* addr = reinterpret_cast<volatile char*>(ptrace_op & 0xFFF);
*addr = '\0';
for (;;)
_exit(1);
}
intptr_t SIGSYSSocketFailure(const struct arch_seccomp_data& args, void* aux) {
static constexpr char kSeccompSocketError[] =
__FILE__ ":**CRASHING**:" SECCOMP_MESSAGE_SOCKET_CONTENT "\n";
WriteToStdErr(kSeccompSocketError, sizeof(kSeccompSocketError) - 1);
char arguments[128];
ssize_t arguments_size = base::strings::SafeSPrintf(
arguments, "domain=0x%x type=0x%x protocol=0x%x\n", args.args[0],
args.args[1], args.args[2]);
WriteToStdErr(arguments, arguments_size);
PrintAndSetSeccompCrashKey(args);
volatile int domain = static_cast<int>(args.args[0]);
volatile int type = static_cast<int>(args.args[1]);
volatile int protocol = static_cast<int>(args.args[2]);
uintptr_t addr = (domain & 0x3ful);
addr |= ((type & 0xful) << 6);
addr |= ((protocol & 0x1ful) << 10);
*reinterpret_cast<volatile char*>(addr) = '\0';
*reinterpret_cast<volatile char*>((domain & 0x3ful) | ((type & 0xful) << 6)) =
'\0';
for (;;) {
_exit(1);
}
}
intptr_t SIGSYSSockoptFailure(const struct arch_seccomp_data& args, void* aux) {
static constexpr char kSeccompSockoptError[] =
__FILE__ ":**CRASHING**:" SECCOMP_MESSAGE_SOCKOPT_CONTENT "\n";
WriteToStdErr(kSeccompSockoptError, sizeof(kSeccompSockoptError) - 1);
char arguments[64];
ssize_t arguments_size = base::strings::SafeSPrintf(
arguments, "level=0x%x optname=0x%x\n", args.args[1], args.args[2]);
WriteToStdErr(arguments, arguments_size);
PrintAndSetSeccompCrashKey(args);
volatile int level = static_cast<int>(args.args[1]);
volatile int optname = static_cast<int>(args.args[2]);
uintptr_t addr = (level & 0x1fful);
addr |= ((optname & 0x7ful) << 9);
*reinterpret_cast<volatile char*>(addr) = '\0';
*reinterpret_cast<volatile char*>((level & 0x1fful)) = '\0';
for (;;) {
_exit(1);
}
}
intptr_t SIGSYSSchedHandler(const struct arch_seccomp_data& args,
void* aux) {
switch (args.nr) {
case __NR_sched_getaffinity:
case __NR_sched_getattr:
case __NR_sched_getparam:
case __NR_sched_getscheduler:
case __NR_sched_rr_get_interval:
case __NR_sched_setaffinity:
case __NR_sched_setattr:
case __NR_sched_setparam:
case __NR_sched_setscheduler:
const pid_t tid = sys_gettid();
if (args.args[0] == static_cast<uint64_t>(tid)) {
return Syscall::Call(args.nr,
0,
static_cast<intptr_t>(args.args[1]),
static_cast<intptr_t>(args.args[2]),
static_cast<intptr_t>(args.args[3]),
static_cast<intptr_t>(args.args[4]),
static_cast<intptr_t>(args.args[5]));
}
break;
}
CrashSIGSYS_Handler(args, aux);
RAW_CHECK(false);
return -ENOSYS;
}
intptr_t SIGSYSFstatatHandler(const struct arch_seccomp_data& args,
void* fs_denied_errno) {
if (args.nr == __NR_fstatat_default) {
if (*reinterpret_cast<const char*>(args.args[1]) == '\0' &&
args.args[3] == static_cast<uint64_t>(AT_EMPTY_PATH)) {
return syscall(__NR_fstat_default, static_cast<int>(args.args[0]),
reinterpret_cast<default_stat_struct*>(args.args[2]));
}
return -reinterpret_cast<intptr_t>(fs_denied_errno);
}
CrashSIGSYS_Handler(args, fs_denied_errno);
RAW_CHECK(false);
return -ENOSYS;
}
bpf_dsl::ResultExpr CrashSIGSYS() {
return bpf_dsl::Trap(CrashSIGSYS_Handler, nullptr);
}
bpf_dsl::ResultExpr CrashSIGSYSClone() {
return bpf_dsl::Trap(SIGSYSCloneFailure, nullptr);
}
bpf_dsl::ResultExpr CrashSIGSYSPrctl() {
return bpf_dsl::Trap(SIGSYSPrctlFailure, nullptr);
}
bpf_dsl::ResultExpr CrashSIGSYSIoctl() {
return bpf_dsl::Trap(SIGSYSIoctlFailure, nullptr);
}
bpf_dsl::ResultExpr CrashSIGSYSKill() {
return bpf_dsl::Trap(SIGSYSKillFailure, nullptr);
}
bpf_dsl::ResultExpr CrashSIGSYSFutex() {
return bpf_dsl::Trap(SIGSYSFutexFailure, nullptr);
}
bpf_dsl::ResultExpr CrashSIGSYSPtrace() {
return bpf_dsl::Trap(SIGSYSPtraceFailure, nullptr);
}
bpf_dsl::ResultExpr CrashSIGSYSSocket() {
return bpf_dsl::Trap(SIGSYSSocketFailure, nullptr);
}
bpf_dsl::ResultExpr CrashSIGSYSSockopt() {
return bpf_dsl::Trap(SIGSYSSockoptFailure, nullptr);
}
bpf_dsl::ResultExpr RewriteSchedSIGSYS() {
return bpf_dsl::Trap(SIGSYSSchedHandler, nullptr);
}
bpf_dsl::ResultExpr RewriteFstatatSIGSYS(int fs_denied_errno) {
return bpf_dsl::Trap(SIGSYSFstatatHandler,
reinterpret_cast<void*>(fs_denied_errno));
}
#if defined(__NR_socketcall)
bool CanRewriteSocketcall() {
static bool can_rewrite_socketcall = []() {
base::ScopedFD socket_fd(
syscall(__NR_socket, 0xffffff, 0xffffff, 0xffffff));
if (!socket_fd.is_valid() && errno == ENOSYS) {
return false;
}
return true;
}();
return can_rewrite_socketcall;
}
intptr_t SIGSYSSocketcallHandler(const struct arch_seccomp_data& args,
void* aux) {
const long kLastSocketcall = SYS_SENDMMSG;
static const struct {
long sysno;
size_t num_args;
size_t num_zeroes = 0;
} socketcall_args[kLastSocketcall + 1] = {
{.sysno = -1, .num_args = 0},
{.sysno = __NR_socket, .num_args = 3},
{.sysno = __NR_bind, .num_args = 3},
{.sysno = __NR_connect, .num_args = 3},
{.sysno = __NR_listen, .num_args = 2},
{.sysno = __NR_accept4, .num_args = 3, .num_zeroes = 1},
{.sysno = __NR_getsockname, .num_args = 3},
{.sysno = __NR_getpeername, .num_args = 3},
{.sysno = __NR_socketpair, .num_args = 4},
{.sysno = __NR_sendto, .num_args = 4, .num_zeroes = 2},
{.sysno = __NR_recvfrom, .num_args = 4, .num_zeroes = 2},
{.sysno = __NR_sendto, .num_args = 6},
{.sysno = __NR_recvfrom, .num_args = 6},
{.sysno = __NR_shutdown, .num_args = 2},
{.sysno = __NR_setsockopt, .num_args = 5},
{.sysno = __NR_getsockopt, .num_args = 5},
{.sysno = __NR_sendmsg, .num_args = 3},
{.sysno = __NR_recvmsg, .num_args = 3},
{.sysno = __NR_accept4, .num_args = 4},
{.sysno = __NR_recvmmsg, .num_args = 5},
{.sysno = __NR_sendmmsg, .num_args = 4}};
uint64_t call = args.args[0];
if (args.nr == __NR_socketcall && 0 < call && call <= kLastSocketcall) {
const size_t real_args_arr_len =
UNSAFE_TODO(socketcall_args[call]).num_args +
UNSAFE_TODO(socketcall_args[call]).num_zeroes;
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wvla-extension"
unsigned long real_args_arr[real_args_arr_len];
#pragma clang diagnostic pop
UNSAFE_TODO(memcpy(real_args_arr,
reinterpret_cast<unsigned long*>(args.args[1]),
real_args_arr_len * sizeof(unsigned long)));
UNSAFE_TODO(
memset(real_args_arr + socketcall_args[call].num_args, 0,
socketcall_args[call].num_zeroes * sizeof(unsigned long)));
switch (real_args_arr_len) {
case 2:
return syscall(UNSAFE_TODO(socketcall_args[call]).sysno,
real_args_arr[0], UNSAFE_TODO(real_args_arr[1]));
case 3:
return syscall(UNSAFE_TODO(socketcall_args[call]).sysno,
real_args_arr[0], UNSAFE_TODO(real_args_arr[1]),
UNSAFE_TODO(real_args_arr[2]));
case 4:
return syscall(UNSAFE_TODO(socketcall_args[call]).sysno,
real_args_arr[0], UNSAFE_TODO(real_args_arr[1]),
UNSAFE_TODO(real_args_arr[2]),
UNSAFE_TODO(real_args_arr[3]));
case 5:
return syscall(
UNSAFE_TODO(socketcall_args[call]).sysno, real_args_arr[0],
UNSAFE_TODO(real_args_arr[1]), UNSAFE_TODO(real_args_arr[2]),
UNSAFE_TODO(real_args_arr[3]), UNSAFE_TODO(real_args_arr[4]));
case 6:
return syscall(
UNSAFE_TODO(socketcall_args[call]).sysno, real_args_arr[0],
UNSAFE_TODO(real_args_arr[1]), UNSAFE_TODO(real_args_arr[2]),
UNSAFE_TODO(real_args_arr[3]), UNSAFE_TODO(real_args_arr[4]),
UNSAFE_TODO(real_args_arr[5]));
default:
break;
}
}
CrashSIGSYS_Handler(args, aux);
RAW_CHECK(false);
return -ENOSYS;
}
bpf_dsl::ResultExpr RewriteSocketcallSIGSYS() {
return bpf_dsl::Trap(SIGSYSSocketcallHandler, nullptr);
}
#endif
void AllocateCrashKeys() {
if (seccomp_crash_key)
return;
seccomp_crash_key = base::debug::AllocateCrashKeyString(
"seccomp-sigsys", base::debug::CrashKeySize::Size256);
seccomp_ioctl_crash_key = base::debug::AllocateCrashKeyString(
"seccomp-sigsys-ioctl", base::debug::CrashKeySize::Size256);
}
const char* GetErrorMessageContentForTests() {
return SECCOMP_MESSAGE_COMMON_CONTENT;
}
const char* GetCloneErrorMessageContentForTests() {
return SECCOMP_MESSAGE_CLONE_CONTENT;
}
const char* GetPrctlErrorMessageContentForTests() {
return SECCOMP_MESSAGE_PRCTL_CONTENT;
}
const char* GetIoctlErrorMessageContentForTests() {
return SECCOMP_MESSAGE_IOCTL_CONTENT;
}
const char* GetKillErrorMessageContentForTests() {
return SECCOMP_MESSAGE_KILL_CONTENT;
}
const char* GetFutexErrorMessageContentForTests() {
return SECCOMP_MESSAGE_FUTEX_CONTENT;
}
const char* GetPtraceErrorMessageContentForTests() {
return SECCOMP_MESSAGE_PTRACE_CONTENT;
}
const char* GetSocketErrorMessageContentForTests() {
return SECCOMP_MESSAGE_SOCKET_CONTENT;
}
const char* GetSockoptErrorMessageContentForTests() {
return SECCOMP_MESSAGE_SOCKOPT_CONTENT;
}
}