freebsd-nq/capmode.cc

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// Test routines to make sure a variety of system calls are or are not
// available in capability mode. The goal is not to see if they work, just
// whether or not they return the expected ECAPMODE.
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/mount.h>
#include <sys/mman.h>
#include <sys/wait.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <sys/ptrace.h>
#include <dirent.h>
#include <netinet/in.h>
#include <fcntl.h>
#include <sched.h>
#include <time.h>
#include <unistd.h>
#include <pthread.h>
#include "capsicum.h"
#include "syscalls.h"
#include "capsicum-test.h"
// Test fixture that opens (and closes) a bunch of files.
class WithFiles : public ::testing::Test {
public:
WithFiles() :
fd_file_(open(TmpFile("cap_capmode"), O_RDWR|O_CREAT, 0644)),
fd_close_(open("/dev/null", O_RDWR)),
fd_dir_(open(tmpdir.c_str(), O_RDONLY)),
fd_socket_(socket(PF_INET, SOCK_DGRAM, 0)),
fd_tcp_socket_(socket(PF_INET, SOCK_STREAM, 0)) {
EXPECT_OK(fd_file_);
EXPECT_OK(fd_close_);
EXPECT_OK(fd_dir_);
EXPECT_OK(fd_socket_);
EXPECT_OK(fd_tcp_socket_);
}
~WithFiles() {
if (fd_tcp_socket_ >= 0) close(fd_tcp_socket_);
if (fd_socket_ >= 0) close(fd_socket_);
if (fd_dir_ >= 0) close(fd_dir_);
if (fd_close_ >= 0) close(fd_close_);
if (fd_file_ >= 0) close(fd_file_);
unlink(TmpFile("cap_capmode"));
}
protected:
int fd_file_;
int fd_close_;
int fd_dir_;
int fd_socket_;
int fd_tcp_socket_;
};
FORK_TEST_F(WithFiles, DisallowedFileSyscalls) {
unsigned int mode = -1;
EXPECT_OK(cap_getmode(&mode));
EXPECT_EQ(0, (int)mode);
EXPECT_OK(cap_enter()); // Enter capability mode.
EXPECT_OK(cap_getmode(&mode));
EXPECT_EQ(1, (int)mode);
// System calls that are not permitted in capability mode.
EXPECT_CAPMODE(access(TmpFile("cap_capmode_access"), F_OK));
EXPECT_CAPMODE(acct(TmpFile("cap_capmode_acct")));
EXPECT_CAPMODE(chdir(TmpFile("cap_capmode_chdir")));
#ifdef HAVE_CHFLAGS
EXPECT_CAPMODE(chflags(TmpFile("cap_capmode_chflags"), UF_NODUMP));
#endif
EXPECT_CAPMODE(chmod(TmpFile("cap_capmode_chmod"), 0644));
EXPECT_CAPMODE(chown(TmpFile("cap_capmode_chown"), -1, -1));
EXPECT_CAPMODE(chroot(TmpFile("cap_capmode_chroot")));
EXPECT_CAPMODE(creat(TmpFile("cap_capmode_creat"), 0644));
EXPECT_CAPMODE(fchdir(fd_dir_));
#ifdef HAVE_GETFSSTAT
struct statfs statfs;
EXPECT_CAPMODE(getfsstat(&statfs, sizeof(statfs), MNT_NOWAIT));
#endif
EXPECT_CAPMODE(link(TmpFile("foo"), TmpFile("bar")));
struct stat sb;
EXPECT_CAPMODE(lstat(TmpFile("cap_capmode_lstat"), &sb));
EXPECT_CAPMODE(mknod(TmpFile("capmode_mknod"), 0644 | S_IFIFO, 0));
EXPECT_CAPMODE(bogus_mount_());
EXPECT_CAPMODE(open("/dev/null", O_RDWR));
char buf[64];
EXPECT_CAPMODE(readlink(TmpFile("cap_capmode_readlink"), buf, sizeof(buf)));
#ifdef HAVE_REVOKE
EXPECT_CAPMODE(revoke(TmpFile("cap_capmode_revoke")));
#endif
EXPECT_CAPMODE(stat(TmpFile("cap_capmode_stat"), &sb));
EXPECT_CAPMODE(symlink(TmpFile("cap_capmode_symlink_from"), TmpFile("cap_capmode_symlink_to")));
EXPECT_CAPMODE(unlink(TmpFile("cap_capmode_unlink")));
EXPECT_CAPMODE(umount2("/not_mounted", 0));
}
FORK_TEST_F(WithFiles, DisallowedSocketSyscalls) {
EXPECT_OK(cap_enter()); // Enter capability mode.
// System calls that are not permitted in capability mode.
struct sockaddr_in addr;
addr.sin_family = AF_INET;
addr.sin_port = 0;
addr.sin_addr.s_addr = htonl(INADDR_ANY);
EXPECT_CAPMODE(bind_(fd_socket_, (sockaddr*)&addr, sizeof(addr)));
addr.sin_family = AF_INET;
addr.sin_port = 53;
addr.sin_addr.s_addr = htonl(0x08080808);
EXPECT_CAPMODE(connect_(fd_tcp_socket_, (sockaddr*)&addr, sizeof(addr)));
}
FORK_TEST_F(WithFiles, AllowedFileSyscalls) {
int rc;
EXPECT_OK(cap_enter()); // Enter capability mode.
EXPECT_OK(close(fd_close_));
fd_close_ = -1;
int fd_dup = dup(fd_file_);
EXPECT_OK(fd_dup);
EXPECT_OK(dup2(fd_file_, fd_dup));
#ifdef HAVE_DUP3
EXPECT_OK(dup3(fd_file_, fd_dup, 0));
#endif
if (fd_dup >= 0) close(fd_dup);
struct stat sb;
EXPECT_OK(fstat(fd_file_, &sb));
EXPECT_OK(lseek(fd_file_, 0, SEEK_SET));
char ch;
EXPECT_OK(read(fd_file_, &ch, sizeof(ch)));
EXPECT_OK(write(fd_file_, &ch, sizeof(ch)));
#ifdef HAVE_CHFLAGS
rc = fchflags(fd_file_, UF_NODUMP);
if (rc < 0) EXPECT_NE(ECAPMODE, errno);
#endif
char buf[1024];
rc = getdents_(fd_dir_, (void*)buf, sizeof(buf));
EXPECT_OK(rc);
char data[] = "123";
EXPECT_OK(pwrite(fd_file_, data, 1, 0));
EXPECT_OK(pread(fd_file_, data, 1, 0));
struct iovec io;
io.iov_base = data;
io.iov_len = 2;
#if !defined(__i386__) && !defined(__linux__)
// TODO(drysdale): reinstate these tests for 32-bit runs when possible
// libc bug is fixed.
EXPECT_OK(pwritev(fd_file_, &io, 1, 0));
EXPECT_OK(preadv(fd_file_, &io, 1, 0));
#endif
EXPECT_OK(writev(fd_file_, &io, 1));
EXPECT_OK(readv(fd_file_, &io, 1));
#ifdef HAVE_SYNCFS
EXPECT_OK(syncfs(fd_file_));
#endif
#ifdef HAVE_SYNC_FILE_RANGE
EXPECT_OK(sync_file_range(fd_file_, 0, 1, 0));
#endif
#ifdef HAVE_READAHEAD
if (!tmpdir_on_tmpfs) { // tmpfs doesn't support readahead(2)
EXPECT_OK(readahead(fd_file_, 0, 1));
}
#endif
}
FORK_TEST_F(WithFiles, AllowedSocketSyscalls) {
EXPECT_OK(cap_enter()); // Enter capability mode.
// recvfrom() either returns -1 with EAGAIN, or 0.
int rc = recvfrom(fd_socket_, NULL, 0, MSG_DONTWAIT, NULL, NULL);
if (rc < 0) EXPECT_EQ(EAGAIN, errno);
char ch;
EXPECT_OK(write(fd_file_, &ch, sizeof(ch)));
// These calls will fail for lack of e.g. a proper name to send to,
// but they are allowed in capability mode, so errno != ECAPMODE.
EXPECT_FAIL_NOT_CAPMODE(accept(fd_socket_, NULL, NULL));
EXPECT_FAIL_NOT_CAPMODE(getpeername(fd_socket_, NULL, NULL));
EXPECT_FAIL_NOT_CAPMODE(getsockname(fd_socket_, NULL, NULL));
EXPECT_FAIL_NOT_CAPMODE(recvmsg(fd_socket_, NULL, 0));
EXPECT_FAIL_NOT_CAPMODE(sendmsg(fd_socket_, NULL, 0));
EXPECT_FAIL_NOT_CAPMODE(sendto(fd_socket_, NULL, 0, 0, NULL, 0));
off_t offset = 0;
EXPECT_FAIL_NOT_CAPMODE(sendfile_(fd_socket_, fd_file_, &offset, 1));
// The socket/socketpair syscalls are allowed, but they don't give
// anything externally useful (can't call bind/connect on them).
int fd_socket2 = socket(PF_INET, SOCK_DGRAM, 0);
EXPECT_OK(fd_socket2);
if (fd_socket2 >= 0) close(fd_socket2);
int fd_pair[2] = {-1, -1};
EXPECT_OK(socketpair(AF_UNIX, SOCK_STREAM, 0, fd_pair));
if (fd_pair[0] >= 0) close(fd_pair[0]);
if (fd_pair[1] >= 0) close(fd_pair[1]);
}
#ifdef HAVE_SEND_RECV_MMSG
FORK_TEST(Capmode, AllowedMmsgSendRecv) {
int fd_socket = socket(PF_INET, SOCK_DGRAM, 0);
struct sockaddr_in addr;
addr.sin_family = AF_INET;
addr.sin_port = htons(0);
addr.sin_addr.s_addr = htonl(INADDR_ANY);
EXPECT_OK(bind(fd_socket, (sockaddr*)&addr, sizeof(addr)));
EXPECT_OK(cap_enter()); // Enter capability mode.
char buffer[256] = {0};
struct iovec iov;
iov.iov_base = buffer;
iov.iov_len = sizeof(buffer);
struct mmsghdr mm;
memset(&mm, 0, sizeof(mm));
mm.msg_hdr.msg_iov = &iov;
mm.msg_hdr.msg_iovlen = 1;
struct timespec ts;
ts.tv_sec = 1;
ts.tv_nsec = 100;
EXPECT_FAIL_NOT_CAPMODE(recvmmsg(fd_socket, &mm, 1, MSG_DONTWAIT, &ts));
EXPECT_FAIL_NOT_CAPMODE(sendmmsg(fd_socket, &mm, 1, 0));
close(fd_socket);
}
#endif
FORK_TEST(Capmode, AllowedIdentifierSyscalls) {
// Record some identifiers
gid_t my_gid = getgid();
pid_t my_pid = getpid();
pid_t my_ppid = getppid();
uid_t my_uid = getuid();
pid_t my_sid = getsid(my_pid);
EXPECT_OK(cap_enter()); // Enter capability mode.
EXPECT_EQ(my_gid, getegid_());
EXPECT_EQ(my_uid, geteuid_());
EXPECT_EQ(my_gid, getgid_());
EXPECT_EQ(my_pid, getpid());
EXPECT_EQ(my_ppid, getppid());
EXPECT_EQ(my_uid, getuid_());
EXPECT_EQ(my_sid, getsid(my_pid));
gid_t grps[128];
EXPECT_OK(getgroups_(128, grps));
uid_t ruid;
uid_t euid;
uid_t suid;
EXPECT_OK(getresuid(&ruid, &euid, &suid));
gid_t rgid;
gid_t egid;
gid_t sgid;
EXPECT_OK(getresgid(&rgid, &egid, &sgid));
#ifdef HAVE_GETLOGIN
EXPECT_TRUE(getlogin() != NULL);
#endif
// Set various identifiers (to their existing values).
EXPECT_OK(setgid(my_gid));
#ifdef HAVE_SETFSGID
EXPECT_OK(setfsgid(my_gid));
#endif
EXPECT_OK(setuid(my_uid));
#ifdef HAVE_SETFSUID
EXPECT_OK(setfsuid(my_uid));
#endif
EXPECT_OK(setregid(my_gid, my_gid));
EXPECT_OK(setresgid(my_gid, my_gid, my_gid));
EXPECT_OK(setreuid(my_uid, my_uid));
EXPECT_OK(setresuid(my_uid, my_uid, my_uid));
EXPECT_OK(setsid());
}
FORK_TEST(Capmode, AllowedSchedSyscalls) {
EXPECT_OK(cap_enter()); // Enter capability mode.
int policy = sched_getscheduler(0);
EXPECT_OK(policy);
struct sched_param sp;
EXPECT_OK(sched_getparam(0, &sp));
if (policy >= 0 && (!SCHED_SETSCHEDULER_REQUIRES_ROOT || getuid() == 0)) {
EXPECT_OK(sched_setscheduler(0, policy, &sp));
}
EXPECT_OK(sched_setparam(0, &sp));
EXPECT_OK(sched_get_priority_max(policy));
EXPECT_OK(sched_get_priority_min(policy));
struct timespec ts;
EXPECT_OK(sched_rr_get_interval(0, &ts));
EXPECT_OK(sched_yield());
}
FORK_TEST(Capmode, AllowedTimerSyscalls) {
EXPECT_OK(cap_enter()); // Enter capability mode.
struct timespec ts;
EXPECT_OK(clock_getres(CLOCK_REALTIME, &ts));
EXPECT_OK(clock_gettime(CLOCK_REALTIME, &ts));
struct itimerval itv;
EXPECT_OK(getitimer(ITIMER_REAL, &itv));
EXPECT_OK(setitimer(ITIMER_REAL, &itv, NULL));
struct timeval tv;
struct timezone tz;
EXPECT_OK(gettimeofday(&tv, &tz));
ts.tv_sec = 0;
ts.tv_nsec = 1;
EXPECT_OK(nanosleep(&ts, NULL));
}
FORK_TEST(Capmode, AllowedProfilSyscall) {
EXPECT_OK(cap_enter()); // Enter capability mode.
char sbuf[32];
EXPECT_OK(profil((profil_arg1_t*)sbuf, sizeof(sbuf), 0, 1));
}
FORK_TEST(Capmode, AllowedResourceSyscalls) {
EXPECT_OK(cap_enter()); // Enter capability mode.
errno = 0;
int rc = getpriority(PRIO_PROCESS, 0);
EXPECT_EQ(0, errno);
EXPECT_OK(setpriority(PRIO_PROCESS, 0, rc));
struct rlimit rlim;
EXPECT_OK(getrlimit_(RLIMIT_CORE, &rlim));
EXPECT_OK(setrlimit(RLIMIT_CORE, &rlim));
struct rusage ruse;
EXPECT_OK(getrusage(RUSAGE_SELF, &ruse));
}
FORK_TEST(CapMode, AllowedMmapSyscalls) {
// mmap() some memory.
size_t mem_size = getpagesize();
void *mem = mmap(NULL, mem_size, PROT_READ|PROT_WRITE, MAP_SHARED|MAP_ANONYMOUS, -1, 0);
EXPECT_TRUE(mem != NULL);
EXPECT_OK(cap_enter()); // Enter capability mode.
EXPECT_OK(msync(mem, mem_size, MS_ASYNC));
EXPECT_OK(madvise(mem, mem_size, MADV_NORMAL));
unsigned char vec[2];
EXPECT_OK(mincore_(mem, mem_size, vec));
EXPECT_OK(mprotect(mem, mem_size, PROT_READ|PROT_WRITE));
if (!MLOCK_REQUIRES_ROOT || getuid() == 0) {
EXPECT_OK(mlock(mem, mem_size));
EXPECT_OK(munlock(mem, mem_size));
int rc = mlockall(MCL_CURRENT);
if (rc != 0) {
// mlockall may well fail with ENOMEM for non-root users, as the
// default RLIMIT_MEMLOCK value isn't that big.
EXPECT_NE(ECAPMODE, errno);
}
EXPECT_OK(munlockall());
}
// Unmap the memory.
EXPECT_OK(munmap(mem, mem_size));
}
FORK_TEST(Capmode, AllowedPipeSyscalls) {
EXPECT_OK(cap_enter()); // Enter capability mode
int fd2[2];
int rc = pipe(fd2);
EXPECT_EQ(0, rc);
#ifdef HAVE_VMSPLICE
char buf[11] = "0123456789";
struct iovec iov;
iov.iov_base = buf;
iov.iov_len = sizeof(buf);
EXPECT_FAIL_NOT_CAPMODE(vmsplice(fd2[0], &iov, 1, SPLICE_F_NONBLOCK));
#endif
if (rc == 0) {
close(fd2[0]);
close(fd2[1]);
};
#ifdef HAVE_PIPE2
rc = pipe2(fd2, 0);
EXPECT_EQ(0, rc);
if (rc == 0) {
close(fd2[0]);
close(fd2[1]);
};
#endif
}
TEST(Capmode, AllowedAtSyscalls) {
int rc = mkdir(TmpFile("cap_at_syscalls"), 0755);
EXPECT_OK(rc);
if (rc < 0 && errno != EEXIST) return;
int dfd = open(TmpFile("cap_at_syscalls"), O_RDONLY);
EXPECT_OK(dfd);
int file = openat(dfd, "testfile", O_RDONLY|O_CREAT, 0644);
EXPECT_OK(file);
EXPECT_OK(close(file));
pid_t child = fork();
if (child == 0) {
// Child: enter cap mode and run tests
EXPECT_OK(cap_enter()); // Enter capability mode
struct stat fs;
EXPECT_OK(fstatat(dfd, "testfile", &fs, 0));
EXPECT_OK(mkdirat(dfd, "subdir", 0600));
EXPECT_OK(fchmodat(dfd, "subdir", 0644, 0));
EXPECT_OK(faccessat(dfd, "subdir", F_OK, 0));
EXPECT_OK(renameat(dfd, "subdir", dfd, "subdir2"));
EXPECT_OK(renameat(dfd, "subdir2", dfd, "subdir"));
struct timeval tv[2];
struct timezone tz;
EXPECT_OK(gettimeofday(&tv[0], &tz));
EXPECT_OK(gettimeofday(&tv[1], &tz));
EXPECT_OK(futimesat(dfd, "testfile", tv));
EXPECT_OK(fchownat(dfd, "testfile", fs.st_uid, fs.st_gid, 0));
EXPECT_OK(linkat(dfd, "testfile", dfd, "linky", 0));
EXPECT_OK(symlinkat("testfile", dfd, "symlink"));
char buffer[256];
EXPECT_OK(readlinkat(dfd, "symlink", buffer, sizeof(buffer)));
EXPECT_OK(unlinkat(dfd, "linky", 0));
EXPECT_OK(unlinkat(dfd, "subdir", AT_REMOVEDIR));
// Check that invalid requests get a non-Capsicum errno.
errno = 0;
rc = readlinkat(-1, "symlink", buffer, sizeof(buffer));
EXPECT_GE(0, rc);
EXPECT_NE(ECAPMODE, errno);
exit(HasFailure());
}
// Wait for the child.
int status;
EXPECT_EQ(child, waitpid(child, &status, 0));
rc = WIFEXITED(status) ? WEXITSTATUS(status) : -1;
EXPECT_EQ(0, rc);
// Tidy up.
close(dfd);
rmdir(TmpFile("cap_at_syscalls/subdir"));
unlink(TmpFile("cap_at_syscalls/symlink"));
unlink(TmpFile("cap_at_syscalls/linky"));
unlink(TmpFile("cap_at_syscalls/testfile"));
rmdir(TmpFile("cap_at_syscalls"));
}
TEST(Capmode, AllowedAtSyscallsCwd) {
int rc = mkdir(TmpFile("cap_at_syscalls_cwd"), 0755);
EXPECT_OK(rc);
if (rc < 0 && errno != EEXIST) return;
int dfd = open(TmpFile("cap_at_syscalls_cwd"), O_RDONLY);
EXPECT_OK(dfd);
int file = openat(dfd, "testfile", O_RDONLY|O_CREAT, 0644);
EXPECT_OK(file);
EXPECT_OK(close(file));
pid_t child = fork();
if (child == 0) {
// Child: move into temp dir, enter cap mode and run tests
EXPECT_OK(fchdir(dfd));
EXPECT_OK(cap_enter()); // Enter capability mode
// Test that *at(AT_FDCWD, path,...) is policed with ECAPMODE.
EXPECT_CAPMODE(openat(AT_FDCWD, "testfile", O_RDONLY));
struct stat fs;
EXPECT_CAPMODE(fstatat(AT_FDCWD, "testfile", &fs, 0));
EXPECT_CAPMODE(mkdirat(AT_FDCWD, "subdir", 0600));
EXPECT_CAPMODE(fchmodat(AT_FDCWD, "subdir", 0644, 0));
EXPECT_CAPMODE(faccessat(AT_FDCWD, "subdir", F_OK, 0));
EXPECT_CAPMODE(renameat(AT_FDCWD, "subdir", AT_FDCWD, "subdir2"));
EXPECT_CAPMODE(renameat(AT_FDCWD, "subdir2", AT_FDCWD, "subdir"));
struct timeval tv[2];
struct timezone tz;
EXPECT_OK(gettimeofday(&tv[0], &tz));
EXPECT_OK(gettimeofday(&tv[1], &tz));
EXPECT_CAPMODE(futimesat(AT_FDCWD, "testfile", tv));
EXPECT_CAPMODE(fchownat(AT_FDCWD, "testfile", fs.st_uid, fs.st_gid, 0));
EXPECT_CAPMODE(linkat(AT_FDCWD, "testfile", AT_FDCWD, "linky", 0));
EXPECT_CAPMODE(symlinkat("testfile", AT_FDCWD, "symlink"));
char buffer[256];
EXPECT_CAPMODE(readlinkat(AT_FDCWD, "symlink", buffer, sizeof(buffer)));
EXPECT_CAPMODE(unlinkat(AT_FDCWD, "linky", 0));
exit(HasFailure());
}
// Wait for the child.
int status;
EXPECT_EQ(child, waitpid(child, &status, 0));
rc = WIFEXITED(status) ? WEXITSTATUS(status) : -1;
EXPECT_EQ(0, rc);
// Tidy up.
close(dfd);
rmdir(TmpFile("cap_at_syscalls_cwd/subdir"));
unlink(TmpFile("cap_at_syscalls_cwd/symlink"));
unlink(TmpFile("cap_at_syscalls_cwd/linky"));
unlink(TmpFile("cap_at_syscalls_cwd/testfile"));
rmdir(TmpFile("cap_at_syscalls_cwd"));
}
TEST(Capmode, Abort) {
// Check that abort(3) works even in capability mode.
pid_t child = fork();
if (child == 0) {
// Child: enter capability mode and call abort(3).
// Triggers something like kill(getpid(), SIGABRT).
cap_enter(); // Enter capability mode.
abort();
exit(99);
}
int status;
EXPECT_EQ(child, waitpid(child, &status, 0));
EXPECT_TRUE(WIFSIGNALED(status)) << " status = " << std::hex << status;
EXPECT_EQ(SIGABRT, WTERMSIG(status)) << " status = " << std::hex << status;
}
FORK_TEST_F(WithFiles, AllowedMiscSyscalls) {
umask(022);
mode_t um_before = umask(022);
EXPECT_OK(cap_enter()); // Enter capability mode.
mode_t um = umask(022);
EXPECT_NE(-ECAPMODE, (int)um);
EXPECT_EQ(um_before, um);
stack_t ss;
EXPECT_OK(sigaltstack(NULL, &ss));
// Finally, tests for system calls that don't fit the pattern very well.
pid_t pid = fork();
EXPECT_OK(pid);
if (pid == 0) {
// Child: almost immediately exit.
sleep(1);
exit(0);
} else if (pid > 0) {
errno = 0;
EXPECT_CAPMODE(ptrace_(PTRACE_PEEKDATA_, pid, &pid, NULL));
EXPECT_CAPMODE(waitpid(pid, NULL, 0));
}
// No error return from sync(2) to test, but check errno remains unset.
errno = 0;
sync();
EXPECT_EQ(0, errno);
// TODO(FreeBSD): ktrace
#ifdef HAVE_SYSARCH
// sysarch() is, by definition, architecture-dependent
#if defined (__amd64__) || defined (__i386__)
long sysarch_arg = 0;
EXPECT_CAPMODE(sysarch(I386_SET_IOPERM, &sysarch_arg));
#else
// TOOD(jra): write a test for arm
FAIL("capmode:no sysarch() test for current architecture");
#endif
#endif
}
void *thread_fn(void *p) {
int delay = *(int *)p;
sleep(delay);
EXPECT_OK(getpid_());
EXPECT_CAPMODE(open("/dev/null", O_RDWR));
return NULL;
}
// Check that restrictions are the same in subprocesses and threads
FORK_TEST(Capmode, NewThread) {
// Fire off a new thread before entering capability mode
pthread_t early_thread;
int one = 1; // second
EXPECT_OK(pthread_create(&early_thread, NULL, thread_fn, &one));
// Fire off a new process before entering capability mode.
int early_child = fork();
EXPECT_OK(early_child);
if (early_child == 0) {
// Child: wait and then confirm this process is unaffect by capability mode in the parent.
sleep(1);
int fd = open("/dev/null", O_RDWR);
EXPECT_OK(fd);
close(fd);
exit(0);
}
EXPECT_OK(cap_enter()); // Enter capability mode.
// Do an allowed syscall.
EXPECT_OK(getpid_());
int child = fork();
EXPECT_OK(child);
if (child == 0) {
// Child: do an allowed and a disallowed syscall.
EXPECT_OK(getpid_());
EXPECT_CAPMODE(open("/dev/null", O_RDWR));
exit(0);
}
// Don't (can't) wait for either child.
// Wait for the early-started thread.
EXPECT_OK(pthread_join(early_thread, NULL));
// Fire off a new thread.
pthread_t child_thread;
int zero = 0; // seconds
EXPECT_OK(pthread_create(&child_thread, NULL, thread_fn, &zero));
EXPECT_OK(pthread_join(child_thread, NULL));
// Fork a subprocess which fires off a new thread.
child = fork();
EXPECT_OK(child);
if (child == 0) {
pthread_t child_thread2;
EXPECT_OK(pthread_create(&child_thread2, NULL, thread_fn, &zero));
EXPECT_OK(pthread_join(child_thread2, NULL));
exit(0);
}
// Sleep for a bit to allow the subprocess to finish.
sleep(2);
}
static int had_signal = 0;
static void handle_signal(int x) { had_signal = 1; }
FORK_TEST(Capmode, SelfKill) {
pid_t me = getpid();
sighandler_t original = signal(SIGUSR1, handle_signal);
pid_t child = fork();
if (child == 0) {
// Child: sleep and exit
sleep(1);
exit(0);
}
EXPECT_OK(cap_enter()); // Enter capability mode.
// Can only kill(2) to own pid.
EXPECT_CAPMODE(kill(child, SIGUSR1));
EXPECT_OK(kill(me, SIGUSR1));
EXPECT_EQ(1, had_signal);
signal(SIGUSR1, original);
}