ladybird/Libraries/LibC/unistd.cpp
Sergey Bugaev dd54d13d8d Kernel+LibC: Allow passing mount flags to chroot()
Since a chroot is in many ways similar to a separate root mount, we can also
apply mount flags to it as if it was an actual mount. These flags will apply
whenever the chrooted process accesses its root directory, but not when other
processes access this same directory for the outside. Since it's common to
chdir("/") immediately after chrooting (so that files accessed through the
current directory inherit the same mount flags), this effectively allows one to
apply additional limitations to a process confined inside a chroot.

To this effect, sys$chroot() gains a mount_flags argument (exposed as
chroot_with_mount_flags() in userspace) which can be set to all the same values
as the flags argument for sys$mount(), and additionally to -1 to keep the flags
set for that file system. Note that passing 0 as mount_flags will unset any
flags that may have been set for the file system, not keep them.
2020-01-12 20:02:11 +01:00

672 lines
14 KiB
C++

#include <AK/ScopedValueRollback.h>
#include <AK/String.h>
#include <AK/Vector.h>
#include <Kernel/Syscall.h>
#include <alloca.h>
#include <assert.h>
#include <errno.h>
#include <fcntl.h>
#include <grp.h>
#include <pwd.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.h>
#include <sys/types.h>
#include <termios.h>
#include <unistd.h>
extern "C" {
int systrace(pid_t pid)
{
int rc = syscall(SC_systrace, pid);
__RETURN_WITH_ERRNO(rc, rc, -1);
}
int chown(const char* pathname, uid_t uid, gid_t gid)
{
if (!pathname) {
errno = EFAULT;
return -1;
}
Syscall::SC_chown_params params { { pathname, strlen(pathname) }, uid, gid };
int rc = syscall(SC_chown, &params);
__RETURN_WITH_ERRNO(rc, rc, -1);
}
int fchown(int fd, uid_t uid, gid_t gid)
{
int rc = syscall(SC_fchown, fd, uid, gid);
__RETURN_WITH_ERRNO(rc, rc, -1);
}
pid_t fork()
{
int rc = syscall(SC_fork);
__RETURN_WITH_ERRNO(rc, rc, -1);
}
int execv(const char* path, char* const argv[])
{
return execve(path, argv, environ);
}
int execve(const char* filename, char* const argv[], char* const envp[])
{
size_t arg_count = 0;
for (size_t i = 0; argv[i]; ++i)
++arg_count;
size_t env_count = 0;
for (size_t i = 0; envp[i]; ++i)
++env_count;
auto copy_strings = [&](auto& vec, size_t count, auto& output) {
output.length = count;
for (size_t i = 0; vec[i]; ++i) {
output.strings[i].characters = vec[i];
output.strings[i].length = strlen(vec[i]);
}
};
Syscall::SC_execve_params params;
params.arguments.strings = (Syscall::StringArgument*)alloca(arg_count * sizeof(Syscall::StringArgument));
params.environment.strings = (Syscall::StringArgument*)alloca(env_count * sizeof(Syscall::StringArgument));
params.path = { filename, strlen(filename) };
copy_strings(argv, arg_count, params.arguments);
copy_strings(envp, env_count, params.environment);
int rc = syscall(SC_execve, &params);
__RETURN_WITH_ERRNO(rc, rc, -1);
}
int execvpe(const char* filename, char* const argv[], char* const envp[])
{
ScopedValueRollback errno_rollback(errno);
int rc = execve(filename, argv, envp);
if (rc < 0 && errno != ENOENT) {
errno_rollback.set_override_rollback_value(errno);
dbg() << "execvpe() failed on first with" << strerror(errno);
return rc;
}
String path = getenv("PATH");
if (path.is_empty())
path = "/bin:/usr/bin";
auto parts = path.split(':');
for (auto& part : parts) {
auto candidate = String::format("%s/%s", part.characters(), filename);
int rc = execve(candidate.characters(), argv, envp);
if (rc < 0 && errno != ENOENT) {
errno_rollback.set_override_rollback_value(errno);
dbg() << "execvpe() failed on attempt (" << candidate << ") with " << strerror(errno);
return rc;
}
}
errno_rollback.set_override_rollback_value(ENOENT);
dbg() << "execvpe() leaving :(";
return -1;
}
int execvp(const char* filename, char* const argv[])
{
int rc = execvpe(filename, argv, environ);
dbg() << "execvp() about to return " << rc << " with errno=" << errno;
return rc;
}
int execl(const char* filename, const char* arg0, ...)
{
Vector<const char*, 16> args;
args.append(arg0);
va_list ap;
va_start(ap, arg0);
for (;;) {
const char* arg = va_arg(ap, const char*);
if (!arg)
break;
args.append(arg);
}
va_end(ap);
args.append(nullptr);
return execve(filename, const_cast<char* const*>(args.data()), environ);
}
int execlp(const char* filename, const char* arg0, ...)
{
Vector<const char*, 16> args;
args.append(arg0);
va_list ap;
va_start(ap, arg0);
for (;;) {
const char* arg = va_arg(ap, const char*);
if (!arg)
break;
args.append(arg);
}
va_end(ap);
args.append(nullptr);
return execvpe(filename, const_cast<char* const*>(args.data()), environ);
}
uid_t getuid()
{
return syscall(SC_getuid);
}
gid_t getgid()
{
return syscall(SC_getgid);
}
uid_t geteuid()
{
return syscall(SC_geteuid);
}
gid_t getegid()
{
return syscall(SC_getegid);
}
pid_t getpid()
{
return syscall(SC_getpid);
}
pid_t getppid()
{
return syscall(SC_getppid);
}
pid_t setsid()
{
int rc = syscall(SC_setsid);
__RETURN_WITH_ERRNO(rc, rc, -1);
}
pid_t tcgetpgrp(int fd)
{
return ioctl(fd, TIOCGPGRP);
}
int tcsetpgrp(int fd, pid_t pgid)
{
return ioctl(fd, TIOCSPGRP, pgid);
}
int setpgid(pid_t pid, pid_t pgid)
{
int rc = syscall(SC_setpgid, pid, pgid);
__RETURN_WITH_ERRNO(rc, rc, -1);
}
pid_t getpgid(pid_t pid)
{
int rc = syscall(SC_getpgid, pid);
__RETURN_WITH_ERRNO(rc, rc, -1);
}
pid_t getpgrp()
{
int rc = syscall(SC_getpgrp);
__RETURN_WITH_ERRNO(rc, rc, -1);
}
ssize_t read(int fd, void* buf, size_t count)
{
int rc = syscall(SC_read, fd, buf, count);
__RETURN_WITH_ERRNO(rc, rc, -1);
}
ssize_t write(int fd, const void* buf, size_t count)
{
int rc = syscall(SC_write, fd, buf, count);
__RETURN_WITH_ERRNO(rc, rc, -1);
}
int ttyname_r(int fd, char* buffer, size_t size)
{
int rc = syscall(SC_ttyname_r, fd, buffer, size);
__RETURN_WITH_ERRNO(rc, rc, -1);
}
static char ttyname_buf[32];
char* ttyname(int fd)
{
if (ttyname_r(fd, ttyname_buf, sizeof(ttyname_buf)) < 0)
return nullptr;
return ttyname_buf;
}
int close(int fd)
{
int rc = syscall(SC_close, fd);
__RETURN_WITH_ERRNO(rc, rc, -1);
}
pid_t waitpid(pid_t waitee, int* wstatus, int options)
{
int rc = syscall(SC_waitpid, waitee, wstatus, options);
__RETURN_WITH_ERRNO(rc, rc, -1);
}
int lstat(const char* path, struct stat* statbuf)
{
if (!path) {
errno = EFAULT;
return -1;
}
int rc = syscall(SC_lstat, path, strlen(path), statbuf);
__RETURN_WITH_ERRNO(rc, rc, -1);
}
int stat(const char* path, struct stat* statbuf)
{
if (!path) {
errno = EFAULT;
return -1;
}
int rc = syscall(SC_stat, path, strlen(path), statbuf);
__RETURN_WITH_ERRNO(rc, rc, -1);
}
int fstat(int fd, struct stat* statbuf)
{
int rc = syscall(SC_fstat, fd, statbuf);
__RETURN_WITH_ERRNO(rc, rc, -1);
}
int chdir(const char* path)
{
if (!path) {
errno = EFAULT;
return -1;
}
int rc = syscall(SC_chdir, path, strlen(path));
__RETURN_WITH_ERRNO(rc, rc, -1);
}
int fchdir(int fd)
{
int rc = syscall(SC_fchdir, fd);
__RETURN_WITH_ERRNO(rc, rc, -1);
}
char* getcwd(char* buffer, size_t size)
{
if (!buffer) {
size = size ? size : PATH_MAX;
buffer = (char*)malloc(size);
}
int rc = syscall(SC_getcwd, buffer, size);
__RETURN_WITH_ERRNO(rc, buffer, nullptr);
}
char* getwd(char* buf)
{
auto* p = getcwd(buf, PATH_MAX);
return p;
}
int sleep(unsigned seconds)
{
return syscall(SC_sleep, seconds);
}
int usleep(useconds_t usec)
{
return syscall(SC_usleep, usec);
}
int gethostname(char* buffer, size_t size)
{
int rc = syscall(SC_gethostname, buffer, size);
__RETURN_WITH_ERRNO(rc, rc, -1);
}
ssize_t readlink(const char* path, char* buffer, size_t size)
{
Syscall::SC_readlink_params params { { path, strlen(path) }, { buffer, size } };
int rc = syscall(SC_readlink, &params);
__RETURN_WITH_ERRNO(rc, rc, -1);
}
off_t lseek(int fd, off_t offset, int whence)
{
int rc = syscall(SC_lseek, fd, offset, whence);
__RETURN_WITH_ERRNO(rc, rc, -1);
}
int link(const char* old_path, const char* new_path)
{
if (!old_path || !new_path) {
errno = EFAULT;
return -1;
}
Syscall::SC_link_params params { { old_path, strlen(old_path) }, { new_path, strlen(new_path) } };
int rc = syscall(SC_link, &params);
__RETURN_WITH_ERRNO(rc, rc, -1);
}
int unlink(const char* pathname)
{
int rc = syscall(SC_unlink, pathname, strlen(pathname));
__RETURN_WITH_ERRNO(rc, rc, -1);
}
int symlink(const char* target, const char* linkpath)
{
if (!target || !linkpath) {
errno = EFAULT;
return -1;
}
Syscall::SC_symlink_params params { { target, strlen(target) }, { linkpath, strlen(linkpath) } };
int rc = syscall(SC_symlink, &params);
__RETURN_WITH_ERRNO(rc, rc, -1);
}
int rmdir(const char* pathname)
{
if (!pathname) {
errno = EFAULT;
return -1;
}
int rc = syscall(SC_rmdir, pathname, strlen(pathname));
__RETURN_WITH_ERRNO(rc, rc, -1);
}
int isatty(int fd)
{
struct termios dummy;
return tcgetattr(fd, &dummy) == 0;
}
int getdtablesize()
{
int rc = syscall(SC_getdtablesize);
__RETURN_WITH_ERRNO(rc, rc, -1);
}
int dup(int old_fd)
{
int rc = syscall(SC_dup, old_fd);
__RETURN_WITH_ERRNO(rc, rc, -1);
}
int dup2(int old_fd, int new_fd)
{
int rc = syscall(SC_dup2, old_fd, new_fd);
__RETURN_WITH_ERRNO(rc, rc, -1);
}
int setgroups(size_t size, const gid_t* list)
{
int rc = syscall(SC_setgroups, size, list);
__RETURN_WITH_ERRNO(rc, rc, -1);
}
int getgroups(int size, gid_t list[])
{
int rc = syscall(SC_getgroups, size, list);
__RETURN_WITH_ERRNO(rc, rc, -1);
}
int pipe(int pipefd[2])
{
return pipe2(pipefd, 0);
}
int pipe2(int pipefd[2], int flags)
{
int rc = syscall(SC_pipe, pipefd, flags);
__RETURN_WITH_ERRNO(rc, rc, -1);
}
unsigned int alarm(unsigned int seconds)
{
return syscall(SC_alarm, seconds);
}
int setuid(uid_t uid)
{
int rc = syscall(SC_setuid, uid);
__RETURN_WITH_ERRNO(rc, rc, -1);
}
int setgid(uid_t gid)
{
int rc = syscall(SC_setgid, gid);
__RETURN_WITH_ERRNO(rc, rc, -1);
}
int access(const char* pathname, int mode)
{
if (!pathname) {
errno = EFAULT;
return -1;
}
int rc = syscall(SC_access, pathname, strlen(pathname), mode);
__RETURN_WITH_ERRNO(rc, rc, -1);
}
int mknod(const char* pathname, mode_t mode, dev_t dev)
{
if (!pathname) {
errno = EFAULT;
return -1;
}
Syscall::SC_mknod_params params { { pathname, strlen(pathname) }, mode, dev };
int rc = syscall(SC_mknod, &params);
__RETURN_WITH_ERRNO(rc, rc, -1);
}
long fpathconf(int fd, int name)
{
(void)fd;
(void)name;
switch (name) {
case _PC_PATH_MAX:
return PATH_MAX;
case _PC_VDISABLE:
return _POSIX_VDISABLE;
}
ASSERT_NOT_REACHED();
}
long pathconf(const char* path, int name)
{
(void)path;
switch (name) {
case _PC_PATH_MAX:
return PATH_MAX;
case _PC_PIPE_BUF:
return PIPE_BUF;
}
ASSERT_NOT_REACHED();
}
void _exit(int status)
{
syscall(SC_exit, status);
ASSERT_NOT_REACHED();
}
void sync()
{
syscall(SC_sync);
}
int create_shared_buffer(int size, void** buffer)
{
int rc = syscall(SC_create_shared_buffer, size, buffer);
__RETURN_WITH_ERRNO(rc, rc, -1);
}
int share_buffer_with(int shared_buffer_id, pid_t peer_pid)
{
int rc = syscall(SC_share_buffer_with, shared_buffer_id, peer_pid);
__RETURN_WITH_ERRNO(rc, rc, -1);
}
int share_buffer_globally(int shared_buffer_id)
{
int rc = syscall(SC_share_buffer_globally, shared_buffer_id);
__RETURN_WITH_ERRNO(rc, rc, -1);
}
int set_process_icon(int icon_id)
{
int rc = syscall(SC_set_process_icon, icon_id);
__RETURN_WITH_ERRNO(rc, rc, -1);
}
void* get_shared_buffer(int shared_buffer_id)
{
int rc = syscall(SC_get_shared_buffer, shared_buffer_id);
if (rc < 0 && -rc < EMAXERRNO) {
errno = -rc;
return (void*)-1;
}
return (void*)rc;
}
int release_shared_buffer(int shared_buffer_id)
{
int rc = syscall(SC_release_shared_buffer, shared_buffer_id);
__RETURN_WITH_ERRNO(rc, rc, -1);
}
int get_shared_buffer_size(int shared_buffer_id)
{
int rc = syscall(SC_get_shared_buffer_size, shared_buffer_id);
__RETURN_WITH_ERRNO(rc, rc, -1);
}
int seal_shared_buffer(int shared_buffer_id)
{
int rc = syscall(SC_seal_shared_buffer, shared_buffer_id);
__RETURN_WITH_ERRNO(rc, rc, -1);
}
char* getlogin()
{
static char __getlogin_buffer[256];
if (auto* passwd = getpwuid(getuid())) {
strncpy(__getlogin_buffer, passwd->pw_name, sizeof(__getlogin_buffer));
endpwent();
return __getlogin_buffer;
}
endpwent();
return nullptr;
}
int ftruncate(int fd, off_t length)
{
int rc = syscall(SC_ftruncate, fd, length);
__RETURN_WITH_ERRNO(rc, rc, -1);
}
int gettid()
{
return syscall(SC_gettid);
}
int donate(int tid)
{
int rc = syscall(SC_donate, tid);
__RETURN_WITH_ERRNO(rc, rc, -1);
}
void sysbeep()
{
syscall(SC_beep);
}
int fsync(int fd)
{
UNUSED_PARAM(fd);
dbgprintf("FIXME: Implement fsync()\n");
return 0;
}
int halt()
{
int rc = syscall(SC_halt);
__RETURN_WITH_ERRNO(rc, rc, -1);
}
int reboot()
{
int rc = syscall(SC_reboot);
__RETURN_WITH_ERRNO(rc, rc, -1);
}
int mount(const char* source, const char* target, const char* fs_type, int flags)
{
if (!source || !target || !fs_type) {
errno = EFAULT;
return -1;
}
Syscall::SC_mount_params params {
{ source, strlen(source) },
{ target, strlen(target) },
{ fs_type, strlen(fs_type) },
flags
};
int rc = syscall(SC_mount, &params);
__RETURN_WITH_ERRNO(rc, rc, -1);
}
int umount(const char* mountpoint)
{
int rc = syscall(SC_umount, mountpoint, strlen(mountpoint));
__RETURN_WITH_ERRNO(rc, rc, -1);
}
void dump_backtrace()
{
syscall(SC_dump_backtrace);
}
int get_process_name(char* buffer, int buffer_size)
{
int rc = syscall(SC_get_process_name, buffer, buffer_size);
__RETURN_WITH_ERRNO(rc, rc, -1);
}
int chroot(const char* path)
{
return chroot_with_mount_flags(path, -1);
}
int chroot_with_mount_flags(const char* path, int mount_flags)
{
if (!path) {
errno = EFAULT;
return -1;
}
int rc = syscall(SC_chroot, path, strlen(path), mount_flags);
__RETURN_WITH_ERRNO(rc, rc, -1);
}
int pledge(const char* promises, const char* execpromises)
{
Syscall::SC_pledge_params params {
{ promises, promises ? strlen(promises) : 0 },
{ execpromises, execpromises ? strlen(execpromises) : 0 }
};
int rc = syscall(SC_pledge, &params);
__RETURN_WITH_ERRNO(rc, rc, -1);
}
}