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// Tests of Linux-specific functionality
#ifdef __linux__
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <sys/timerfd.h>
#include <sys/signalfd.h>
#include <sys/eventfd.h>
#include <sys/epoll.h>
#include <sys/inotify.h>
#include <sys/fanotify.h>
#include <sys/mman.h>
#include <sys/capability.h> // Requires e.g. libcap-dev package for POSIX.1e capabilities headers
#include <linux/aio_abi.h>
#include <linux/filter.h>
#include <linux/seccomp.h>
#include <linux/version.h>
#include <poll.h>
#include <sched.h>
#include <signal.h>
#include <fcntl.h>
#include <unistd.h>
#include <string>
#include "capsicum.h"
#include "syscalls.h"
#include "capsicum-test.h"
TEST(Linux, TimerFD) {
int fd = timerfd_create(CLOCK_MONOTONIC, 0);
cap_rights_t r_ro;
cap_rights_init(&r_ro, CAP_READ);
cap_rights_t r_wo;
cap_rights_init(&r_wo, CAP_WRITE);
cap_rights_t r_rw;
cap_rights_init(&r_rw, CAP_READ, CAP_WRITE);
cap_rights_t r_rwpoll;
cap_rights_init(&r_rwpoll, CAP_READ, CAP_WRITE, CAP_EVENT);
int cap_fd_ro = dup(fd);
EXPECT_OK(cap_fd_ro);
EXPECT_OK(cap_rights_limit(cap_fd_ro, &r_ro));
int cap_fd_wo = dup(fd);
EXPECT_OK(cap_fd_wo);
EXPECT_OK(cap_rights_limit(cap_fd_wo, &r_wo));
int cap_fd_rw = dup(fd);
EXPECT_OK(cap_fd_rw);
EXPECT_OK(cap_rights_limit(cap_fd_rw, &r_rw));
int cap_fd_all = dup(fd);
EXPECT_OK(cap_fd_all);
EXPECT_OK(cap_rights_limit(cap_fd_all, &r_rwpoll));
struct itimerspec old_ispec;
struct itimerspec ispec;
ispec.it_interval.tv_sec = 0;
ispec.it_interval.tv_nsec = 0;
ispec.it_value.tv_sec = 0;
ispec.it_value.tv_nsec = 100000000; // 100ms
EXPECT_NOTCAPABLE(timerfd_settime(cap_fd_ro, 0, &ispec, NULL));
EXPECT_NOTCAPABLE(timerfd_settime(cap_fd_wo, 0, &ispec, &old_ispec));
EXPECT_OK(timerfd_settime(cap_fd_wo, 0, &ispec, NULL));
EXPECT_OK(timerfd_settime(cap_fd_rw, 0, &ispec, NULL));
EXPECT_OK(timerfd_settime(cap_fd_all, 0, &ispec, NULL));
EXPECT_NOTCAPABLE(timerfd_gettime(cap_fd_wo, &old_ispec));
EXPECT_OK(timerfd_gettime(cap_fd_ro, &old_ispec));
EXPECT_OK(timerfd_gettime(cap_fd_rw, &old_ispec));
EXPECT_OK(timerfd_gettime(cap_fd_all, &old_ispec));
// To be able to poll() for the timer pop, still need CAP_EVENT.
struct pollfd poll_fd;
for (int ii = 0; ii < 3; ii++) {
poll_fd.revents = 0;
poll_fd.events = POLLIN;
switch (ii) {
case 0: poll_fd.fd = cap_fd_ro; break;
case 1: poll_fd.fd = cap_fd_wo; break;
case 2: poll_fd.fd = cap_fd_rw; break;
}
// Poll immediately returns with POLLNVAL
EXPECT_OK(poll(&poll_fd, 1, 400));
EXPECT_EQ(0, (poll_fd.revents & POLLIN));
EXPECT_NE(0, (poll_fd.revents & POLLNVAL));
}
poll_fd.fd = cap_fd_all;
EXPECT_OK(poll(&poll_fd, 1, 400));
EXPECT_NE(0, (poll_fd.revents & POLLIN));
EXPECT_EQ(0, (poll_fd.revents & POLLNVAL));
EXPECT_OK(timerfd_gettime(cap_fd_all, &old_ispec));
EXPECT_EQ(0, old_ispec.it_value.tv_sec);
EXPECT_EQ(0, old_ispec.it_value.tv_nsec);
EXPECT_EQ(0, old_ispec.it_interval.tv_sec);
EXPECT_EQ(0, old_ispec.it_interval.tv_nsec);
close(cap_fd_all);
close(cap_fd_rw);
close(cap_fd_wo);
close(cap_fd_ro);
close(fd);
}
FORK_TEST(Linux, SignalFD) {
if (force_mt) {
TEST_SKIPPED("multi-threaded run clashes with signals");
return;
}
pid_t me = getpid();
sigset_t mask;
sigemptyset(&mask);
sigaddset(&mask, SIGUSR1);
// Block signals before registering against a new signal FD.
EXPECT_OK(sigprocmask(SIG_BLOCK, &mask, NULL));
int fd = signalfd(-1, &mask, 0);
EXPECT_OK(fd);
cap_rights_t r_rs;
cap_rights_init(&r_rs, CAP_READ, CAP_SEEK);
cap_rights_t r_ws;
cap_rights_init(&r_ws, CAP_WRITE, CAP_SEEK);
cap_rights_t r_sig;
cap_rights_init(&r_sig, CAP_FSIGNAL);
cap_rights_t r_rssig;
cap_rights_init(&r_rssig, CAP_FSIGNAL, CAP_READ, CAP_SEEK);
cap_rights_t r_rssig_poll;
cap_rights_init(&r_rssig_poll, CAP_FSIGNAL, CAP_READ, CAP_SEEK, CAP_EVENT);
// Various capability variants.
int cap_fd_none = dup(fd);
EXPECT_OK(cap_fd_none);
EXPECT_OK(cap_rights_limit(cap_fd_none, &r_ws));
int cap_fd_read = dup(fd);
EXPECT_OK(cap_fd_read);
EXPECT_OK(cap_rights_limit(cap_fd_read, &r_rs));
int cap_fd_sig = dup(fd);
EXPECT_OK(cap_fd_sig);
EXPECT_OK(cap_rights_limit(cap_fd_sig, &r_sig));
int cap_fd_sig_read = dup(fd);
EXPECT_OK(cap_fd_sig_read);
EXPECT_OK(cap_rights_limit(cap_fd_sig_read, &r_rssig));
int cap_fd_all = dup(fd);
EXPECT_OK(cap_fd_all);
EXPECT_OK(cap_rights_limit(cap_fd_all, &r_rssig_poll));
struct signalfd_siginfo fdsi;
// Need CAP_READ to read the signal information
kill(me, SIGUSR1);
EXPECT_NOTCAPABLE(read(cap_fd_none, &fdsi, sizeof(struct signalfd_siginfo)));
EXPECT_NOTCAPABLE(read(cap_fd_sig, &fdsi, sizeof(struct signalfd_siginfo)));
int len = read(cap_fd_read, &fdsi, sizeof(struct signalfd_siginfo));
EXPECT_OK(len);
EXPECT_EQ(sizeof(struct signalfd_siginfo), (size_t)len);
EXPECT_EQ(SIGUSR1, (int)fdsi.ssi_signo);
// Need CAP_FSIGNAL to modify the signal mask.
sigemptyset(&mask);
sigaddset(&mask, SIGUSR1);
sigaddset(&mask, SIGUSR2);
EXPECT_OK(sigprocmask(SIG_BLOCK, &mask, NULL));
EXPECT_NOTCAPABLE(signalfd(cap_fd_none, &mask, 0));
EXPECT_NOTCAPABLE(signalfd(cap_fd_read, &mask, 0));
EXPECT_EQ(cap_fd_sig, signalfd(cap_fd_sig, &mask, 0));
// Need CAP_EVENT to get notification of a signal in poll(2).
kill(me, SIGUSR2);
struct pollfd poll_fd;
poll_fd.revents = 0;
poll_fd.events = POLLIN;
poll_fd.fd = cap_fd_sig_read;
EXPECT_OK(poll(&poll_fd, 1, 400));
EXPECT_EQ(0, (poll_fd.revents & POLLIN));
EXPECT_NE(0, (poll_fd.revents & POLLNVAL));
poll_fd.fd = cap_fd_all;
EXPECT_OK(poll(&poll_fd, 1, 400));
EXPECT_NE(0, (poll_fd.revents & POLLIN));
EXPECT_EQ(0, (poll_fd.revents & POLLNVAL));
}
TEST(Linux, EventFD) {
int fd = eventfd(0, 0);
EXPECT_OK(fd);
cap_rights_t r_rs;
cap_rights_init(&r_rs, CAP_READ, CAP_SEEK);
cap_rights_t r_ws;
cap_rights_init(&r_ws, CAP_WRITE, CAP_SEEK);
cap_rights_t r_rws;
cap_rights_init(&r_rws, CAP_READ, CAP_WRITE, CAP_SEEK);
cap_rights_t r_rwspoll;
cap_rights_init(&r_rwspoll, CAP_READ, CAP_WRITE, CAP_SEEK, CAP_EVENT);
int cap_ro = dup(fd);
EXPECT_OK(cap_ro);
EXPECT_OK(cap_rights_limit(cap_ro, &r_rs));
int cap_wo = dup(fd);
EXPECT_OK(cap_wo);
EXPECT_OK(cap_rights_limit(cap_wo, &r_ws));
int cap_rw = dup(fd);
EXPECT_OK(cap_rw);
EXPECT_OK(cap_rights_limit(cap_rw, &r_rws));
int cap_all = dup(fd);
EXPECT_OK(cap_all);
EXPECT_OK(cap_rights_limit(cap_all, &r_rwspoll));
pid_t child = fork();
if (child == 0) {
// Child: write counter to eventfd
uint64_t u = 42;
EXPECT_NOTCAPABLE(write(cap_ro, &u, sizeof(u)));
EXPECT_OK(write(cap_wo, &u, sizeof(u)));
exit(HasFailure());
}
sleep(1); // Allow child to write
struct pollfd poll_fd;
poll_fd.revents = 0;
poll_fd.events = POLLIN;
poll_fd.fd = cap_rw;
EXPECT_OK(poll(&poll_fd, 1, 400));
EXPECT_EQ(0, (poll_fd.revents & POLLIN));
EXPECT_NE(0, (poll_fd.revents & POLLNVAL));
poll_fd.fd = cap_all;
EXPECT_OK(poll(&poll_fd, 1, 400));
EXPECT_NE(0, (poll_fd.revents & POLLIN));
EXPECT_EQ(0, (poll_fd.revents & POLLNVAL));
uint64_t u;
EXPECT_NOTCAPABLE(read(cap_wo, &u, sizeof(u)));
EXPECT_OK(read(cap_ro, &u, sizeof(u)));
EXPECT_EQ(42, (int)u);
// Wait for the child.
int status;
EXPECT_EQ(child, waitpid(child, &status, 0));
int rc = WIFEXITED(status) ? WEXITSTATUS(status) : -1;
EXPECT_EQ(0, rc);
close(cap_all);
close(cap_rw);
close(cap_wo);
close(cap_ro);
close(fd);
}
FORK_TEST(Linux, epoll) {
int sock_fds[2];
EXPECT_OK(socketpair(AF_UNIX, SOCK_STREAM, 0, sock_fds));
// Queue some data.
char buffer[4] = {1, 2, 3, 4};
EXPECT_OK(write(sock_fds[1], buffer, sizeof(buffer)));
EXPECT_OK(cap_enter()); // Enter capability mode.
int epoll_fd = epoll_create(1);
EXPECT_OK(epoll_fd);
cap_rights_t r_rs;
cap_rights_init(&r_rs, CAP_READ, CAP_SEEK);
cap_rights_t r_ws;
cap_rights_init(&r_ws, CAP_WRITE, CAP_SEEK);
cap_rights_t r_rws;
cap_rights_init(&r_rws, CAP_READ, CAP_WRITE, CAP_SEEK);
cap_rights_t r_rwspoll;
cap_rights_init(&r_rwspoll, CAP_READ, CAP_WRITE, CAP_SEEK, CAP_EVENT);
cap_rights_t r_epoll;
cap_rights_init(&r_epoll, CAP_EPOLL_CTL);
int cap_epoll_wo = dup(epoll_fd);
EXPECT_OK(cap_epoll_wo);
EXPECT_OK(cap_rights_limit(cap_epoll_wo, &r_ws));
int cap_epoll_ro = dup(epoll_fd);
EXPECT_OK(cap_epoll_ro);
EXPECT_OK(cap_rights_limit(cap_epoll_ro, &r_rs));
int cap_epoll_rw = dup(epoll_fd);
EXPECT_OK(cap_epoll_rw);
EXPECT_OK(cap_rights_limit(cap_epoll_rw, &r_rws));
int cap_epoll_poll = dup(epoll_fd);
EXPECT_OK(cap_epoll_poll);
EXPECT_OK(cap_rights_limit(cap_epoll_poll, &r_rwspoll));
int cap_epoll_ctl = dup(epoll_fd);
EXPECT_OK(cap_epoll_ctl);
EXPECT_OK(cap_rights_limit(cap_epoll_ctl, &r_epoll));
// Can only modify the FDs being monitored if the CAP_EPOLL_CTL right is present.
struct epoll_event eev;
memset(&eev, 0, sizeof(eev));
eev.events = EPOLLIN|EPOLLOUT|EPOLLPRI;
EXPECT_NOTCAPABLE(epoll_ctl(cap_epoll_ro, EPOLL_CTL_ADD, sock_fds[0], &eev));
EXPECT_NOTCAPABLE(epoll_ctl(cap_epoll_wo, EPOLL_CTL_ADD, sock_fds[0], &eev));
EXPECT_NOTCAPABLE(epoll_ctl(cap_epoll_rw, EPOLL_CTL_ADD, sock_fds[0], &eev));
EXPECT_OK(epoll_ctl(cap_epoll_ctl, EPOLL_CTL_ADD, sock_fds[0], &eev));
eev.events = EPOLLIN|EPOLLOUT;
EXPECT_NOTCAPABLE(epoll_ctl(cap_epoll_ro, EPOLL_CTL_MOD, sock_fds[0], &eev));
EXPECT_NOTCAPABLE(epoll_ctl(cap_epoll_wo, EPOLL_CTL_MOD, sock_fds[0], &eev));
EXPECT_NOTCAPABLE(epoll_ctl(cap_epoll_rw, EPOLL_CTL_MOD, sock_fds[0], &eev));
EXPECT_OK(epoll_ctl(cap_epoll_ctl, EPOLL_CTL_MOD, sock_fds[0], &eev));
// Running epoll_pwait(2) requires CAP_EVENT.
eev.events = 0;
EXPECT_NOTCAPABLE(epoll_pwait(cap_epoll_ro, &eev, 1, 100, NULL));
EXPECT_NOTCAPABLE(epoll_pwait(cap_epoll_wo, &eev, 1, 100, NULL));
EXPECT_NOTCAPABLE(epoll_pwait(cap_epoll_rw, &eev, 1, 100, NULL));
EXPECT_OK(epoll_pwait(cap_epoll_poll, &eev, 1, 100, NULL));
EXPECT_EQ(EPOLLIN, eev.events & EPOLLIN);
EXPECT_NOTCAPABLE(epoll_ctl(cap_epoll_ro, EPOLL_CTL_DEL, sock_fds[0], &eev));
EXPECT_NOTCAPABLE(epoll_ctl(cap_epoll_wo, EPOLL_CTL_DEL, sock_fds[0], &eev));
EXPECT_NOTCAPABLE(epoll_ctl(cap_epoll_rw, EPOLL_CTL_DEL, sock_fds[0], &eev));
EXPECT_OK(epoll_ctl(epoll_fd, EPOLL_CTL_DEL, sock_fds[0], &eev));
close(cap_epoll_ctl);
close(cap_epoll_poll);
close(cap_epoll_rw);
close(cap_epoll_ro);
close(cap_epoll_wo);
close(epoll_fd);
close(sock_fds[1]);
close(sock_fds[0]);
}
TEST(Linux, fstatat) {
int fd = open(TmpFile("cap_fstatat"), O_CREAT|O_RDWR, 0644);
EXPECT_OK(fd);
unsigned char buffer[] = {1, 2, 3, 4};
EXPECT_OK(write(fd, buffer, sizeof(buffer)));
cap_rights_t rights;
int cap_rf = dup(fd);
EXPECT_OK(cap_rf);
EXPECT_OK(cap_rights_limit(cap_rf, cap_rights_init(&rights, CAP_READ, CAP_FSTAT)));
int cap_ro = dup(fd);
EXPECT_OK(cap_ro);
EXPECT_OK(cap_rights_limit(cap_ro, cap_rights_init(&rights, CAP_READ)));
struct stat info;
EXPECT_OK(fstatat(fd, "", &info, AT_EMPTY_PATH));
EXPECT_NOTCAPABLE(fstatat(cap_ro, "", &info, AT_EMPTY_PATH));
EXPECT_OK(fstatat(cap_rf, "", &info, AT_EMPTY_PATH));
close(cap_ro);
close(cap_rf);
close(fd);
int dir = open(tmpdir.c_str(), O_RDONLY);
EXPECT_OK(dir);
int dir_rf = dup(dir);
EXPECT_OK(dir_rf);
EXPECT_OK(cap_rights_limit(dir_rf, cap_rights_init(&rights, CAP_READ, CAP_FSTAT)));
int dir_ro = dup(fd);
EXPECT_OK(dir_ro);
EXPECT_OK(cap_rights_limit(dir_ro, cap_rights_init(&rights, CAP_READ)));
EXPECT_OK(fstatat(dir, "cap_fstatat", &info, AT_EMPTY_PATH));
EXPECT_NOTCAPABLE(fstatat(dir_ro, "cap_fstatat", &info, AT_EMPTY_PATH));
EXPECT_OK(fstatat(dir_rf, "cap_fstatat", &info, AT_EMPTY_PATH));
close(dir_ro);
close(dir_rf);
close(dir);
unlink(TmpFile("cap_fstatat"));
}
// fanotify support may not be available at compile-time
#ifdef __NR_fanotify_init
TEST(Linux, fanotify) {
REQUIRE_ROOT();
int fa_fd = fanotify_init(FAN_CLASS_NOTIF, O_RDWR);
EXPECT_OK(fa_fd);
if (fa_fd < 0) return; // May not be enabled
cap_rights_t r_rs;
cap_rights_init(&r_rs, CAP_READ, CAP_SEEK);
cap_rights_t r_ws;
cap_rights_init(&r_ws, CAP_WRITE, CAP_SEEK);
cap_rights_t r_rws;
cap_rights_init(&r_rws, CAP_READ, CAP_WRITE, CAP_SEEK);
cap_rights_t r_rwspoll;
cap_rights_init(&r_rwspoll, CAP_READ, CAP_WRITE, CAP_SEEK, CAP_EVENT);
cap_rights_t r_rwsnotify;
cap_rights_init(&r_rwsnotify, CAP_READ, CAP_WRITE, CAP_SEEK, CAP_NOTIFY);
cap_rights_t r_rsl;
cap_rights_init(&r_rsl, CAP_READ, CAP_SEEK, CAP_LOOKUP);
cap_rights_t r_rslstat;
cap_rights_init(&r_rslstat, CAP_READ, CAP_SEEK, CAP_LOOKUP, CAP_FSTAT);
cap_rights_t r_rsstat;
cap_rights_init(&r_rsstat, CAP_READ, CAP_SEEK, CAP_FSTAT);
int cap_fd_ro = dup(fa_fd);
EXPECT_OK(cap_fd_ro);
EXPECT_OK(cap_rights_limit(cap_fd_ro, &r_rs));
int cap_fd_wo = dup(fa_fd);
EXPECT_OK(cap_fd_wo);
EXPECT_OK(cap_rights_limit(cap_fd_wo, &r_ws));
int cap_fd_rw = dup(fa_fd);
EXPECT_OK(cap_fd_rw);
EXPECT_OK(cap_rights_limit(cap_fd_rw, &r_rws));
int cap_fd_poll = dup(fa_fd);
EXPECT_OK(cap_fd_poll);
EXPECT_OK(cap_rights_limit(cap_fd_poll, &r_rwspoll));
int cap_fd_not = dup(fa_fd);
EXPECT_OK(cap_fd_not);
EXPECT_OK(cap_rights_limit(cap_fd_not, &r_rwsnotify));
int rc = mkdir(TmpFile("cap_notify"), 0755);
EXPECT_TRUE(rc == 0 || errno == EEXIST);
int dfd = open(TmpFile("cap_notify"), O_RDONLY);
EXPECT_OK(dfd);
int fd = open(TmpFile("cap_notify/file"), O_CREAT|O_RDWR, 0644);
close(fd);
int cap_dfd = dup(dfd);
EXPECT_OK(cap_dfd);
EXPECT_OK(cap_rights_limit(cap_dfd, &r_rslstat));
EXPECT_OK(cap_dfd);
int cap_dfd_rs = dup(dfd);
EXPECT_OK(cap_dfd_rs);
EXPECT_OK(cap_rights_limit(cap_dfd_rs, &r_rs));
EXPECT_OK(cap_dfd_rs);
int cap_dfd_rsstat = dup(dfd);
EXPECT_OK(cap_dfd_rsstat);
EXPECT_OK(cap_rights_limit(cap_dfd_rsstat, &r_rsstat));
EXPECT_OK(cap_dfd_rsstat);
int cap_dfd_rsl = dup(dfd);
EXPECT_OK(cap_dfd_rsl);
EXPECT_OK(cap_rights_limit(cap_dfd_rsl, &r_rsl));
EXPECT_OK(cap_dfd_rsl);
// Need CAP_NOTIFY to change what's monitored.
EXPECT_NOTCAPABLE(fanotify_mark(cap_fd_ro, FAN_MARK_ADD, FAN_OPEN|FAN_MODIFY|FAN_EVENT_ON_CHILD, cap_dfd, NULL));
EXPECT_NOTCAPABLE(fanotify_mark(cap_fd_wo, FAN_MARK_ADD, FAN_OPEN|FAN_MODIFY|FAN_EVENT_ON_CHILD, cap_dfd, NULL));
EXPECT_NOTCAPABLE(fanotify_mark(cap_fd_rw, FAN_MARK_ADD, FAN_OPEN|FAN_MODIFY|FAN_EVENT_ON_CHILD, cap_dfd, NULL));
EXPECT_OK(fanotify_mark(cap_fd_not, FAN_MARK_ADD, FAN_OPEN|FAN_MODIFY|FAN_EVENT_ON_CHILD, cap_dfd, NULL));
// Need CAP_FSTAT on the thing monitored.
EXPECT_NOTCAPABLE(fanotify_mark(cap_fd_not, FAN_MARK_ADD, FAN_OPEN|FAN_MODIFY|FAN_EVENT_ON_CHILD, cap_dfd_rs, NULL));
EXPECT_OK(fanotify_mark(cap_fd_not, FAN_MARK_ADD, FAN_OPEN|FAN_MODIFY|FAN_EVENT_ON_CHILD, cap_dfd_rsstat, NULL));
// Too add monitoring of a file under a dfd, need CAP_LOOKUP|CAP_FSTAT on the dfd.
EXPECT_NOTCAPABLE(fanotify_mark(cap_fd_not, FAN_MARK_ADD, FAN_OPEN|FAN_MODIFY, cap_dfd_rsstat, "file"));
EXPECT_NOTCAPABLE(fanotify_mark(cap_fd_not, FAN_MARK_ADD, FAN_OPEN|FAN_MODIFY, cap_dfd_rsl, "file"));
EXPECT_OK(fanotify_mark(cap_fd_not, FAN_MARK_ADD, FAN_OPEN|FAN_MODIFY, cap_dfd, "file"));
pid_t child = fork();
if (child == 0) {
// Child: Perform activity in the directory under notify.
sleep(1);
unlink(TmpFile("cap_notify/temp"));
int fd = open(TmpFile("cap_notify/temp"), O_CREAT|O_RDWR, 0644);
close(fd);
exit(0);
}
// Need CAP_EVENT to poll.
struct pollfd poll_fd;
poll_fd.revents = 0;
poll_fd.events = POLLIN;
poll_fd.fd = cap_fd_rw;
EXPECT_OK(poll(&poll_fd, 1, 1400));
EXPECT_EQ(0, (poll_fd.revents & POLLIN));
EXPECT_NE(0, (poll_fd.revents & POLLNVAL));
poll_fd.fd = cap_fd_not;
EXPECT_OK(poll(&poll_fd, 1, 1400));
EXPECT_EQ(0, (poll_fd.revents & POLLIN));
EXPECT_NE(0, (poll_fd.revents & POLLNVAL));
poll_fd.fd = cap_fd_poll;
EXPECT_OK(poll(&poll_fd, 1, 1400));
EXPECT_NE(0, (poll_fd.revents & POLLIN));
EXPECT_EQ(0, (poll_fd.revents & POLLNVAL));
// Need CAP_READ to read.
struct fanotify_event_metadata ev;
memset(&ev, 0, sizeof(ev));
EXPECT_NOTCAPABLE(read(cap_fd_wo, &ev, sizeof(ev)));
rc = read(fa_fd, &ev, sizeof(ev));
EXPECT_OK(rc);
EXPECT_EQ((int)sizeof(struct fanotify_event_metadata), rc);
EXPECT_EQ(child, ev.pid);
EXPECT_NE(0, ev.fd);
// TODO(drysdale): reinstate if/when capsicum-linux propagates rights
// to fanotify-generated FDs.
#ifdef OMIT
// fanotify(7) gives us a FD for the changed file. This should
// only have rights that are a subset of those for the original
// monitored directory file descriptor.
cap_rights_t rights;
CAP_SET_ALL(&rights);
EXPECT_OK(cap_rights_get(ev.fd, &rights));
EXPECT_RIGHTS_IN(&rights, &r_rslstat);
#endif
// Wait for the child.
int status;
EXPECT_EQ(child, waitpid(child, &status, 0));
rc = WIFEXITED(status) ? WEXITSTATUS(status) : -1;
EXPECT_EQ(0, rc);
close(cap_dfd_rsstat);
close(cap_dfd_rsl);
close(cap_dfd_rs);
close(cap_dfd);
close(dfd);
unlink(TmpFile("cap_notify/file"));
unlink(TmpFile("cap_notify/temp"));
rmdir(TmpFile("cap_notify"));
close(cap_fd_not);
close(cap_fd_poll);
close(cap_fd_rw);
close(cap_fd_wo);
close(cap_fd_ro);
close(fa_fd);
}
#endif
TEST(Linux, inotify) {
int i_fd = inotify_init();
EXPECT_OK(i_fd);
cap_rights_t r_rs;
cap_rights_init(&r_rs, CAP_READ, CAP_SEEK);
cap_rights_t r_ws;
cap_rights_init(&r_ws, CAP_WRITE, CAP_SEEK);
cap_rights_t r_rws;
cap_rights_init(&r_rws, CAP_READ, CAP_WRITE, CAP_SEEK);
cap_rights_t r_rwsnotify;
cap_rights_init(&r_rwsnotify, CAP_READ, CAP_WRITE, CAP_SEEK, CAP_NOTIFY);
int cap_fd_ro = dup(i_fd);
EXPECT_OK(cap_fd_ro);
EXPECT_OK(cap_rights_limit(cap_fd_ro, &r_rs));
int cap_fd_wo = dup(i_fd);
EXPECT_OK(cap_fd_wo);
EXPECT_OK(cap_rights_limit(cap_fd_wo, &r_ws));
int cap_fd_rw = dup(i_fd);
EXPECT_OK(cap_fd_rw);
EXPECT_OK(cap_rights_limit(cap_fd_rw, &r_rws));
int cap_fd_all = dup(i_fd);
EXPECT_OK(cap_fd_all);
EXPECT_OK(cap_rights_limit(cap_fd_all, &r_rwsnotify));
int fd = open(TmpFile("cap_inotify"), O_CREAT|O_RDWR, 0644);
EXPECT_NOTCAPABLE(inotify_add_watch(cap_fd_rw, TmpFile("cap_inotify"), IN_ACCESS|IN_MODIFY));
int wd = inotify_add_watch(i_fd, TmpFile("cap_inotify"), IN_ACCESS|IN_MODIFY);
EXPECT_OK(wd);
unsigned char buffer[] = {1, 2, 3, 4};
EXPECT_OK(write(fd, buffer, sizeof(buffer)));
struct inotify_event iev;
memset(&iev, 0, sizeof(iev));
EXPECT_NOTCAPABLE(read(cap_fd_wo, &iev, sizeof(iev)));
int rc = read(cap_fd_ro, &iev, sizeof(iev));
EXPECT_OK(rc);
EXPECT_EQ((int)sizeof(iev), rc);
EXPECT_EQ(wd, iev.wd);
EXPECT_NOTCAPABLE(inotify_rm_watch(cap_fd_wo, wd));
EXPECT_OK(inotify_rm_watch(cap_fd_all, wd));
close(fd);
close(cap_fd_all);
close(cap_fd_rw);
close(cap_fd_wo);
close(cap_fd_ro);
close(i_fd);
unlink(TmpFile("cap_inotify"));
}
TEST(Linux, ArchChange) {
const char* prog_candidates[] = {"./mini-me.32", "./mini-me.x32", "./mini-me.64"};
const char* progs[] = {NULL, NULL, NULL};
char* argv_pass[] = {(char*)"to-come", (char*)"--capmode", NULL};
char* null_envp[] = {NULL};
int fds[3];
int count = 0;
for (int ii = 0; ii < 3; ii++) {
fds[count] = open(prog_candidates[ii], O_RDONLY);
if (fds[count] >= 0) {
progs[count] = prog_candidates[ii];
count++;
}
}
if (count == 0) {
TEST_SKIPPED("no different-architecture programs available");
return;
}
for (int ii = 0; ii < count; ii++) {
// Fork-and-exec a binary of this architecture.
pid_t child = fork();
if (child == 0) {
EXPECT_OK(cap_enter()); // Enter capability mode
if (verbose) fprintf(stderr, "[%d] call fexecve(%s, %s)\n",
getpid_(), progs[ii], argv_pass[1]);
argv_pass[0] = (char *)progs[ii];
int rc = fexecve_(fds[ii], argv_pass, null_envp);
fprintf(stderr, "fexecve(%s) returned %d errno %d\n", progs[ii], rc, errno);
exit(99); // Should not reach here.
}
int status;
EXPECT_EQ(child, waitpid(child, &status, 0));
int rc = WIFEXITED(status) ? WEXITSTATUS(status) : -1;
EXPECT_EQ(0, rc);
close(fds[ii]);
}
}
FORK_TEST(Linux, Namespace) {
REQUIRE_ROOT();
pid_t me = getpid_();
// Create a new UTS namespace.
EXPECT_OK(unshare(CLONE_NEWUTS));
// Open an FD to its symlink.
char buffer[256];
sprintf(buffer, "/proc/%d/ns/uts", me);
int ns_fd = open(buffer, O_RDONLY);
cap_rights_t r_rwlstat;
cap_rights_init(&r_rwlstat, CAP_READ, CAP_WRITE, CAP_LOOKUP, CAP_FSTAT);
cap_rights_t r_rwlstatns;
cap_rights_init(&r_rwlstatns, CAP_READ, CAP_WRITE, CAP_LOOKUP, CAP_FSTAT, CAP_SETNS);
int cap_fd = dup(ns_fd);
EXPECT_OK(cap_fd);
EXPECT_OK(cap_rights_limit(cap_fd, &r_rwlstat));
int cap_fd_setns = dup(ns_fd);
EXPECT_OK(cap_fd_setns);
EXPECT_OK(cap_rights_limit(cap_fd_setns, &r_rwlstatns));
EXPECT_NOTCAPABLE(setns(cap_fd, CLONE_NEWUTS));
EXPECT_OK(setns(cap_fd_setns, CLONE_NEWUTS));
EXPECT_OK(cap_enter()); // Enter capability mode.
// No setns(2) but unshare(2) is allowed.
EXPECT_CAPMODE(setns(ns_fd, CLONE_NEWUTS));
EXPECT_OK(unshare(CLONE_NEWUTS));
}
static void SendFD(int fd, int over) {
struct msghdr mh;
mh.msg_name = NULL; // No address needed
mh.msg_namelen = 0;
char buffer1[1024];
struct iovec iov[1];
iov[0].iov_base = buffer1;
iov[0].iov_len = sizeof(buffer1);
mh.msg_iov = iov;
mh.msg_iovlen = 1;
char buffer2[1024];
mh.msg_control = buffer2;
mh.msg_controllen = CMSG_LEN(sizeof(int));
struct cmsghdr *cmptr = CMSG_FIRSTHDR(&mh);
cmptr->cmsg_level = SOL_SOCKET;
cmptr->cmsg_type = SCM_RIGHTS;
cmptr->cmsg_len = CMSG_LEN(sizeof(int));
*(int *)CMSG_DATA(cmptr) = fd;
buffer1[0] = 0;
iov[0].iov_len = 1;
int rc = sendmsg(over, &mh, 0);
EXPECT_OK(rc);
}
static int ReceiveFD(int over) {
struct msghdr mh;
mh.msg_name = NULL; // No address needed
mh.msg_namelen = 0;
char buffer1[1024];
struct iovec iov[1];
iov[0].iov_base = buffer1;
iov[0].iov_len = sizeof(buffer1);
mh.msg_iov = iov;
mh.msg_iovlen = 1;
char buffer2[1024];
mh.msg_control = buffer2;
mh.msg_controllen = sizeof(buffer2);
int rc = recvmsg(over, &mh, 0);
EXPECT_OK(rc);
EXPECT_LE(CMSG_LEN(sizeof(int)), mh.msg_controllen);
struct cmsghdr *cmptr = CMSG_FIRSTHDR(&mh);
int fd = *(int*)CMSG_DATA(cmptr);
EXPECT_EQ(CMSG_LEN(sizeof(int)), cmptr->cmsg_len);
cmptr = CMSG_NXTHDR(&mh, cmptr);
EXPECT_TRUE(cmptr == NULL);
return fd;
}
static int shared_pd = -1;
static int shared_sock_fds[2];
static int ChildFunc(void *arg) {
// This function is running in a new PID namespace, and so is pid 1.
if (verbose) fprintf(stderr, " ChildFunc: pid=%d, ppid=%d\n", getpid_(), getppid());
EXPECT_EQ(1, getpid_());
EXPECT_EQ(0, getppid());
// The shared process descriptor is outside our namespace, so we cannot
// get its pid.
if (verbose) fprintf(stderr, " ChildFunc: shared_pd=%d\n", shared_pd);
pid_t shared_child = -1;
EXPECT_OK(pdgetpid(shared_pd, &shared_child));
if (verbose) fprintf(stderr, " ChildFunc: corresponding pid=%d\n", shared_child);
EXPECT_EQ(0, shared_child);
// But we can pdkill() it even so.
if (verbose) fprintf(stderr, " ChildFunc: call pdkill(pd=%d)\n", shared_pd);
EXPECT_OK(pdkill(shared_pd, SIGINT));
int pd;
pid_t child = pdfork(&pd, 0);
EXPECT_OK(child);
if (child == 0) {
// Child: expect pid 2.
if (verbose) fprintf(stderr, " child of ChildFunc: pid=%d, ppid=%d\n", getpid_(), getppid());
EXPECT_EQ(2, getpid_());
EXPECT_EQ(1, getppid());
while (true) {
if (verbose) fprintf(stderr, " child of ChildFunc: \"I aten't dead\"\n");
sleep(1);
}
exit(0);
}
EXPECT_EQ(2, child);
EXPECT_PID_ALIVE(child);
if (verbose) fprintf(stderr, " ChildFunc: pdfork() -> pd=%d, corresponding pid=%d state='%c'\n",
pd, child, ProcessState(child));
pid_t pid;
EXPECT_OK(pdgetpid(pd, &pid));
EXPECT_EQ(child, pid);
sleep(2);
// Send the process descriptor over UNIX domain socket back to parent.
SendFD(pd, shared_sock_fds[1]);
// Wait for death of (grand)child, killed by our parent.
if (verbose) fprintf(stderr, " ChildFunc: wait on pid=%d\n", child);
int status;
EXPECT_EQ(child, wait4(child, &status, __WALL, NULL));
if (verbose) fprintf(stderr, " ChildFunc: return 0\n");
return 0;
}
#define STACK_SIZE (1024 * 1024)
static char child_stack[STACK_SIZE];
// TODO(drysdale): fork into a user namespace first so REQUIRE_ROOT can be removed.
TEST(Linux, PidNamespacePdFork) {
REQUIRE_ROOT();
// Pass process descriptors in both directions across a PID namespace boundary.
// pdfork() off a child before we start, holding its process descriptor in a global
// variable that's accessible to children.
pid_t firstborn = pdfork(&shared_pd, 0);
EXPECT_OK(firstborn);
if (firstborn == 0) {
while (true) {
if (verbose) fprintf(stderr, " Firstborn: \"I aten't dead\"\n");
sleep(1);
}
exit(0);
}
EXPECT_PID_ALIVE(firstborn);
if (verbose) fprintf(stderr, "Parent: pre-pdfork()ed pd=%d, pid=%d state='%c'\n",
shared_pd, firstborn, ProcessState(firstborn));
sleep(2);
// Prepare sockets to communicate with child process.
EXPECT_OK(socketpair(AF_UNIX, SOCK_STREAM, 0, shared_sock_fds));
// Clone into a child process with a new pid namespace.
pid_t child = clone(ChildFunc, child_stack + STACK_SIZE,
CLONE_FILES|CLONE_NEWPID|SIGCHLD, NULL);
EXPECT_OK(child);
EXPECT_PID_ALIVE(child);
if (verbose) fprintf(stderr, "Parent: child is %d state='%c'\n", child, ProcessState(child));
// Ensure the child runs. First thing it does is to kill our firstborn, using shared_pd.
sleep(1);
EXPECT_PID_DEAD(firstborn);
// But we can still retrieve firstborn's PID, as it's not been reaped yet.
pid_t child0;
EXPECT_OK(pdgetpid(shared_pd, &child0));
EXPECT_EQ(firstborn, child0);
if (verbose) fprintf(stderr, "Parent: check on firstborn: pdgetpid(pd=%d) -> child=%d state='%c'\n",
shared_pd, child0, ProcessState(child0));
// Now reap it.
int status;
EXPECT_EQ(firstborn, waitpid(firstborn, &status, __WALL));
// Get the process descriptor of the child-of-child via socket transfer.
int grandchild_pd = ReceiveFD(shared_sock_fds[0]);
// Our notion of the pid associated with the grandchild is in the main PID namespace.
pid_t grandchild;
EXPECT_OK(pdgetpid(grandchild_pd, &grandchild));
EXPECT_NE(2, grandchild);
if (verbose) fprintf(stderr, "Parent: pre-pdkill: pdgetpid(grandchild_pd=%d) -> grandchild=%d state='%c'\n",
grandchild_pd, grandchild, ProcessState(grandchild));
EXPECT_PID_ALIVE(grandchild);
// Kill the grandchild via the process descriptor.
EXPECT_OK(pdkill(grandchild_pd, SIGINT));
usleep(10000);
if (verbose) fprintf(stderr, "Parent: post-pdkill: pdgetpid(grandchild_pd=%d) -> grandchild=%d state='%c'\n",
grandchild_pd, grandchild, ProcessState(grandchild));
EXPECT_PID_DEAD(grandchild);
sleep(2);
// Wait for the child.
EXPECT_EQ(child, waitpid(child, &status, WNOHANG));
int rc = WIFEXITED(status) ? WEXITSTATUS(status) : -1;
EXPECT_EQ(0, rc);
close(shared_sock_fds[0]);
close(shared_sock_fds[1]);
close(shared_pd);
close(grandchild_pd);
}
int NSInit(void *data) {
// This function is running in a new PID namespace, and so is pid 1.
if (verbose) fprintf(stderr, " NSInit: pid=%d, ppid=%d\n", getpid_(), getppid());
EXPECT_EQ(1, getpid_());
EXPECT_EQ(0, getppid());
int pd;
pid_t child = pdfork(&pd, 0);
EXPECT_OK(child);
if (child == 0) {
// Child: loop forever until terminated.
if (verbose) fprintf(stderr, " child of NSInit: pid=%d, ppid=%d\n", getpid_(), getppid());
while (true) {
if (verbose) fprintf(stderr, " child of NSInit: \"I aten't dead\"\n");
usleep(100000);
}
exit(0);
}
EXPECT_EQ(2, child);
EXPECT_PID_ALIVE(child);
if (verbose) fprintf(stderr, " NSInit: pdfork() -> pd=%d, corresponding pid=%d state='%c'\n",
pd, child, ProcessState(child));
sleep(1);
// Send the process descriptor over UNIX domain socket back to parent.
SendFD(pd, shared_sock_fds[1]);
close(pd);
// Wait for a byte back in the other direction.
int value;
if (verbose) fprintf(stderr, " NSInit: block waiting for value\n");
read(shared_sock_fds[1], &value, sizeof(value));
if (verbose) fprintf(stderr, " NSInit: return 0\n");
return 0;
}
TEST(Linux, DeadNSInit) {
REQUIRE_ROOT();
// Prepare sockets to communicate with child process.
EXPECT_OK(socketpair(AF_UNIX, SOCK_STREAM, 0, shared_sock_fds));
// Clone into a child process with a new pid namespace.
pid_t child = clone(NSInit, child_stack + STACK_SIZE,
CLONE_FILES|CLONE_NEWPID|SIGCHLD, NULL);
usleep(10000);
EXPECT_OK(child);
EXPECT_PID_ALIVE(child);
if (verbose) fprintf(stderr, "Parent: child is %d state='%c'\n", child, ProcessState(child));
// Get the process descriptor of the child-of-child via socket transfer.
int grandchild_pd = ReceiveFD(shared_sock_fds[0]);
pid_t grandchild;
EXPECT_OK(pdgetpid(grandchild_pd, &grandchild));
if (verbose) fprintf(stderr, "Parent: grandchild is %d state='%c'\n", grandchild, ProcessState(grandchild));
// Send an int to the child to trigger its termination. Grandchild should also
// go, as its init process is gone.
int zero = 0;
if (verbose) fprintf(stderr, "Parent: write 0 to pipe\n");
write(shared_sock_fds[0], &zero, sizeof(zero));
EXPECT_PID_ZOMBIE(child);
EXPECT_PID_GONE(grandchild);
// Wait for the child.
int status;
EXPECT_EQ(child, waitpid(child, &status, WNOHANG));
int rc = WIFEXITED(status) ? WEXITSTATUS(status) : -1;
EXPECT_EQ(0, rc);
EXPECT_PID_GONE(child);
close(shared_sock_fds[0]);
close(shared_sock_fds[1]);
close(grandchild_pd);
if (verbose) {
fprintf(stderr, "Parent: child %d in state='%c'\n", child, ProcessState(child));
fprintf(stderr, "Parent: grandchild %d in state='%c'\n", grandchild, ProcessState(grandchild));
}
}
TEST(Linux, DeadNSInit2) {
REQUIRE_ROOT();
// Prepare sockets to communicate with child process.
EXPECT_OK(socketpair(AF_UNIX, SOCK_STREAM, 0, shared_sock_fds));
// Clone into a child process with a new pid namespace.
pid_t child = clone(NSInit, child_stack + STACK_SIZE,
CLONE_FILES|CLONE_NEWPID|SIGCHLD, NULL);
usleep(10000);
EXPECT_OK(child);
EXPECT_PID_ALIVE(child);
if (verbose) fprintf(stderr, "Parent: child is %d state='%c'\n", child, ProcessState(child));
// Get the process descriptor of the child-of-child via socket transfer.
int grandchild_pd = ReceiveFD(shared_sock_fds[0]);
pid_t grandchild;
EXPECT_OK(pdgetpid(grandchild_pd, &grandchild));
if (verbose) fprintf(stderr, "Parent: grandchild is %d state='%c'\n", grandchild, ProcessState(grandchild));
// Kill the grandchild
EXPECT_OK(pdkill(grandchild_pd, SIGINT));
usleep(10000);
EXPECT_PID_ZOMBIE(grandchild);
// Close the process descriptor, so there are now no procdesc references to grandchild.
close(grandchild_pd);
// Send an int to the child to trigger its termination. Grandchild should also
// go, as its init process is gone.
int zero = 0;
if (verbose) fprintf(stderr, "Parent: write 0 to pipe\n");
write(shared_sock_fds[0], &zero, sizeof(zero));
EXPECT_PID_ZOMBIE(child);
EXPECT_PID_GONE(grandchild);
// Wait for the child.
int status;
EXPECT_EQ(child, waitpid(child, &status, WNOHANG));
int rc = WIFEXITED(status) ? WEXITSTATUS(status) : -1;
EXPECT_EQ(0, rc);
close(shared_sock_fds[0]);
close(shared_sock_fds[1]);
if (verbose) {
fprintf(stderr, "Parent: child %d in state='%c'\n", child, ProcessState(child));
fprintf(stderr, "Parent: grandchild %d in state='%c'\n", grandchild, ProcessState(grandchild));
}
}
#ifdef __x86_64__
FORK_TEST(Linux, CheckHighWord) {
EXPECT_OK(cap_enter()); // Enter capability mode.
int rc = prctl(PR_GET_NO_NEW_PRIVS, 0, 0, 0, 0);
EXPECT_OK(rc);
EXPECT_EQ(1, rc); // no_new_privs = 1
// Set some of the high 32-bits of argument zero.
uint64_t big_cmd = PR_GET_NO_NEW_PRIVS | 0x100000000LL;
EXPECT_CAPMODE(syscall(__NR_prctl, big_cmd, 0, 0, 0, 0));
}
#endif
FORK_TEST(Linux, PrctlOpenatBeneath) {
// Set no_new_privs = 1
EXPECT_OK(prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0));
int rc = prctl(PR_GET_NO_NEW_PRIVS, 0, 0, 0, 0);
EXPECT_OK(rc);
EXPECT_EQ(1, rc); // no_new_privs = 1
// Set openat-beneath mode
EXPECT_OK(prctl(PR_SET_OPENAT_BENEATH, 1, 0, 0, 0));
rc = prctl(PR_GET_OPENAT_BENEATH, 0, 0, 0, 0);
EXPECT_OK(rc);
EXPECT_EQ(1, rc); // openat_beneath = 1
// Clear openat-beneath mode
EXPECT_OK(prctl(PR_SET_OPENAT_BENEATH, 0, 0, 0, 0));
rc = prctl(PR_GET_OPENAT_BENEATH, 0, 0, 0, 0);
EXPECT_OK(rc);
EXPECT_EQ(0, rc); // openat_beneath = 0
EXPECT_OK(cap_enter()); // Enter capability mode
// Expect to be in openat_beneath mode
rc = prctl(PR_GET_OPENAT_BENEATH, 0, 0, 0, 0);
EXPECT_OK(rc);
EXPECT_EQ(1, rc); // openat_beneath = 1
// Expect this to be immutable.
EXPECT_CAPMODE(prctl(PR_SET_OPENAT_BENEATH, 0, 0, 0, 0));
rc = prctl(PR_GET_OPENAT_BENEATH, 0, 0, 0, 0);
EXPECT_OK(rc);
EXPECT_EQ(1, rc); // openat_beneath = 1
}
FORK_TEST(Linux, NoNewPrivs) {
if (getuid() == 0) {
// If root, drop CAP_SYS_ADMIN POSIX.1e capability.
struct __user_cap_header_struct hdr;
hdr.version = _LINUX_CAPABILITY_VERSION_3;
hdr.pid = getpid_();
struct __user_cap_data_struct data[3];
EXPECT_OK(capget(&hdr, &data[0]));
data[0].effective &= ~(1 << CAP_SYS_ADMIN);
data[0].permitted &= ~(1 << CAP_SYS_ADMIN);
data[0].inheritable &= ~(1 << CAP_SYS_ADMIN);
EXPECT_OK(capset(&hdr, &data[0]));
}
int rc = prctl(PR_GET_NO_NEW_PRIVS, 0, 0, 0, 0);
EXPECT_OK(rc);
EXPECT_EQ(0, rc); // no_new_privs == 0
// Can't enter seccomp-bpf mode with no_new_privs == 0
struct sock_filter filter[] = {
BPF_STMT(BPF_RET+BPF_K, SECCOMP_RET_ALLOW)
};
struct sock_fprog bpf;
bpf.len = (sizeof(filter) / sizeof(filter[0]));
bpf.filter = filter;
rc = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &bpf, 0, 0);
EXPECT_EQ(-1, rc);
EXPECT_EQ(EACCES, errno);
// Set no_new_privs = 1
EXPECT_OK(prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0));
rc = prctl(PR_GET_NO_NEW_PRIVS, 0, 0, 0, 0);
EXPECT_OK(rc);
EXPECT_EQ(1, rc); // no_new_privs = 1
// Can now turn on seccomp mode
EXPECT_OK(prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &bpf, 0, 0));
}
/* Macros for BPF generation */
#define BPF_RETURN_ERRNO(err) \
BPF_STMT(BPF_RET+BPF_K, SECCOMP_RET_ERRNO | (err & 0xFFFF))
#define BPF_KILL_PROCESS \
BPF_STMT(BPF_RET+BPF_K, SECCOMP_RET_KILL)
#define BPF_ALLOW \
BPF_STMT(BPF_RET+BPF_K, SECCOMP_RET_ALLOW)
#define EXAMINE_SYSCALL \
BPF_STMT(BPF_LD+BPF_W+BPF_ABS, offsetof(struct seccomp_data, nr))
#define ALLOW_SYSCALL(name) \
BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, __NR_##name, 0, 1), \
BPF_ALLOW
#define KILL_SYSCALL(name) \
BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, __NR_##name, 0, 1), \
BPF_KILL_PROCESS
#define FAIL_SYSCALL(name, err) \
BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, __NR_##name, 0, 1), \
BPF_RETURN_ERRNO(err)
TEST(Linux, CapModeWithBPF) {
pid_t child = fork();
EXPECT_OK(child);
if (child == 0) {
int fd = open(TmpFile("cap_bpf_capmode"), O_CREAT|O_RDWR, 0644);
cap_rights_t rights;
cap_rights_init(&rights, CAP_READ, CAP_WRITE, CAP_SEEK, CAP_FSYNC);
EXPECT_OK(cap_rights_limit(fd, &rights));
struct sock_filter filter[] = { EXAMINE_SYSCALL,
FAIL_SYSCALL(fchmod, ENOMEM),
FAIL_SYSCALL(fstat, ENOEXEC),
ALLOW_SYSCALL(close),
KILL_SYSCALL(fsync),
BPF_ALLOW };
struct sock_fprog bpf = {.len = (sizeof(filter) / sizeof(filter[0])),
.filter = filter};
// Set up seccomp-bpf first.
EXPECT_OK(prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0));
EXPECT_OK(prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &bpf, 0, 0));
EXPECT_OK(cap_enter()); // Enter capability mode.
// fchmod is allowed by Capsicum, but failed by BPF.
EXPECT_SYSCALL_FAIL(ENOMEM, fchmod(fd, 0644));
// open is allowed by BPF, but failed by Capsicum
EXPECT_SYSCALL_FAIL(ECAPMODE, open(TmpFile("cap_bpf_capmode"), O_RDONLY));
// fstat is failed by both BPF and Capsicum; tie-break is on errno
struct stat buf;
EXPECT_SYSCALL_FAIL(ENOEXEC, fstat(fd, &buf));
// fsync is allowed by Capsicum, but BPF's SIGSYS generation take precedence
fsync(fd); // terminate with unhandled SIGSYS
exit(0);
}
int status;
EXPECT_EQ(child, waitpid(child, &status, 0));
EXPECT_TRUE(WIFSIGNALED(status));
EXPECT_EQ(SIGSYS, WTERMSIG(status));
unlink(TmpFile("cap_bpf_capmode"));
}
TEST(Linux, AIO) {
int fd = open(TmpFile("cap_aio"), O_CREAT|O_RDWR, 0644);
EXPECT_OK(fd);
cap_rights_t r_rs;
cap_rights_init(&r_rs, CAP_READ, CAP_SEEK);
cap_rights_t r_ws;
cap_rights_init(&r_ws, CAP_WRITE, CAP_SEEK);
cap_rights_t r_rwssync;
cap_rights_init(&r_rwssync, CAP_READ, CAP_WRITE, CAP_SEEK, CAP_FSYNC);
int cap_ro = dup(fd);
EXPECT_OK(cap_ro);
EXPECT_OK(cap_rights_limit(cap_ro, &r_rs));
EXPECT_OK(cap_ro);
int cap_wo = dup(fd);
EXPECT_OK(cap_wo);
EXPECT_OK(cap_rights_limit(cap_wo, &r_ws));
EXPECT_OK(cap_wo);
int cap_all = dup(fd);
EXPECT_OK(cap_all);
EXPECT_OK(cap_rights_limit(cap_all, &r_rwssync));
EXPECT_OK(cap_all);
// Linux: io_setup, io_submit, io_getevents, io_cancel, io_destroy
aio_context_t ctx = 0;
EXPECT_OK(syscall(__NR_io_setup, 10, &ctx));
unsigned char buffer[32] = {1, 2, 3, 4};
struct iocb req;
memset(&req, 0, sizeof(req));
req.aio_reqprio = 0;
req.aio_fildes = fd;
uintptr_t bufaddr = (uintptr_t)buffer;
req.aio_buf = (__u64)bufaddr;
req.aio_nbytes = 4;
req.aio_offset = 0;
struct iocb* reqs[1] = {&req};
// Write operation
req.aio_lio_opcode = IOCB_CMD_PWRITE;
req.aio_fildes = cap_ro;
EXPECT_NOTCAPABLE(syscall(__NR_io_submit, ctx, 1, reqs));
req.aio_fildes = cap_wo;
EXPECT_OK(syscall(__NR_io_submit, ctx, 1, reqs));
// Sync operation
req.aio_lio_opcode = IOCB_CMD_FSYNC;
EXPECT_NOTCAPABLE(syscall(__NR_io_submit, ctx, 1, reqs));
req.aio_lio_opcode = IOCB_CMD_FDSYNC;
EXPECT_NOTCAPABLE(syscall(__NR_io_submit, ctx, 1, reqs));
// Even with CAP_FSYNC, turns out fsync/fdsync aren't implemented
req.aio_fildes = cap_all;
EXPECT_FAIL_NOT_NOTCAPABLE(syscall(__NR_io_submit, ctx, 1, reqs));
req.aio_lio_opcode = IOCB_CMD_FSYNC;
EXPECT_FAIL_NOT_NOTCAPABLE(syscall(__NR_io_submit, ctx, 1, reqs));
// Read operation
req.aio_lio_opcode = IOCB_CMD_PREAD;
req.aio_fildes = cap_wo;
EXPECT_NOTCAPABLE(syscall(__NR_io_submit, ctx, 1, reqs));
req.aio_fildes = cap_ro;
EXPECT_OK(syscall(__NR_io_submit, ctx, 1, reqs));
EXPECT_OK(syscall(__NR_io_destroy, ctx));
close(cap_all);
close(cap_wo);
close(cap_ro);
close(fd);
unlink(TmpFile("cap_aio"));
}
#ifndef KCMP_FILE
#define KCMP_FILE 0
#endif
TEST(Linux, Kcmp) {
// This requires CONFIG_CHECKPOINT_RESTORE in kernel config.
int fd = open("/etc/passwd", O_RDONLY);
EXPECT_OK(fd);
pid_t parent = getpid_();
errno = 0;
int rc = syscall(__NR_kcmp, parent, parent, KCMP_FILE, fd, fd);
if (rc == -1 && errno == ENOSYS) {
TEST_SKIPPED("kcmp(2) gives -ENOSYS");
return;
}
pid_t child = fork();
if (child == 0) {
// Child: limit rights on FD.
child = getpid_();
EXPECT_OK(syscall(__NR_kcmp, parent, child, KCMP_FILE, fd, fd));
cap_rights_t rights;
cap_rights_init(&rights, CAP_READ, CAP_WRITE);
EXPECT_OK(cap_rights_limit(fd, &rights));
// A capability wrapping a normal FD is different (from a kcmp(2) perspective)
// than the original file.
EXPECT_NE(0, syscall(__NR_kcmp, parent, child, KCMP_FILE, fd, fd));
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);
close(fd);
}
TEST(Linux, ProcFS) {
cap_rights_t rights;
cap_rights_init(&rights, CAP_READ, CAP_SEEK);
int fd = open("/etc/passwd", O_RDONLY);
EXPECT_OK(fd);
lseek(fd, 4, SEEK_SET);
int cap = dup(fd);
EXPECT_OK(cap);
EXPECT_OK(cap_rights_limit(cap, &rights));
pid_t me = getpid_();
char buffer[1024];
sprintf(buffer, "/proc/%d/fdinfo/%d", me, cap);
int procfd = open(buffer, O_RDONLY);
EXPECT_OK(procfd) << " failed to open " << buffer;
if (procfd < 0) return;
int proccap = dup(procfd);
EXPECT_OK(proccap);
EXPECT_OK(cap_rights_limit(proccap, &rights));
EXPECT_OK(read(proccap, buffer, sizeof(buffer)));
// The fdinfo should include the file pos of the underlying file
EXPECT_NE((char*)NULL, strstr(buffer, "pos:\t4"));
// ...and the rights of the Capsicum capability.
EXPECT_NE((char*)NULL, strstr(buffer, "rights:\t0x"));
close(procfd);
close(proccap);
close(cap);
close(fd);
}
FORK_TEST(Linux, ProcessClocks) {
pid_t self = getpid_();
pid_t child = fork();
EXPECT_OK(child);
if (child == 0) {
child = getpid_();
usleep(100000);
exit(0);
}
EXPECT_OK(cap_enter()); // Enter capability mode.
// Nefariously build a clock ID for the child's CPU time.
// This relies on knowledge of the internal layout of clock IDs.
clockid_t child_clock;
child_clock = ((~child) << 3) | 0x0;
struct timespec ts;
memset(&ts, 0, sizeof(ts));
// TODO(drysdale): Should not be possible to retrieve info about a
// different process, as the PID global namespace should be locked
// down.
EXPECT_OK(clock_gettime(child_clock, &ts));
if (verbose) fprintf(stderr, "[parent: %d] clock_gettime(child=%d->0x%08x) is %ld.%09ld \n",
self, child, child_clock, (long)ts.tv_sec, (long)ts.tv_nsec);
child_clock = ((~1) << 3) | 0x0;
memset(&ts, 0, sizeof(ts));
EXPECT_OK(clock_gettime(child_clock, &ts));
if (verbose) fprintf(stderr, "[parent: %d] clock_gettime(init=1->0x%08x) is %ld.%09ld \n",
self, child_clock, (long)ts.tv_sec, (long)ts.tv_nsec);
// Orphan the child.
}
TEST(Linux, SetLease) {
int fd_all = open(TmpFile("cap_lease"), O_CREAT|O_RDWR, 0644);
EXPECT_OK(fd_all);
int fd_rw = dup(fd_all);
EXPECT_OK(fd_rw);
cap_rights_t r_all;
cap_rights_init(&r_all, CAP_READ, CAP_WRITE, CAP_FLOCK, CAP_FSIGNAL);
EXPECT_OK(cap_rights_limit(fd_all, &r_all));
cap_rights_t r_rw;
cap_rights_init(&r_rw, CAP_READ, CAP_WRITE);
EXPECT_OK(cap_rights_limit(fd_rw, &r_rw));
EXPECT_NOTCAPABLE(fcntl(fd_rw, F_SETLEASE, F_WRLCK));
EXPECT_NOTCAPABLE(fcntl(fd_rw, F_GETLEASE));
if (!tmpdir_on_tmpfs) { // tmpfs doesn't support leases
EXPECT_OK(fcntl(fd_all, F_SETLEASE, F_WRLCK));
EXPECT_EQ(F_WRLCK, fcntl(fd_all, F_GETLEASE));
EXPECT_OK(fcntl(fd_all, F_SETLEASE, F_UNLCK, 0));
EXPECT_EQ(F_UNLCK, fcntl(fd_all, F_GETLEASE));
}
close(fd_all);
close(fd_rw);
unlink(TmpFile("cap_lease"));
}
TEST(Linux, InvalidRightsSyscall) {
int fd = open(TmpFile("cap_invalid_rights"), O_RDONLY|O_CREAT, 0644);
EXPECT_OK(fd);
cap_rights_t rights;
cap_rights_init(&rights, CAP_READ, CAP_WRITE, CAP_FCHMOD, CAP_FSTAT);
// Use the raw syscall throughout.
EXPECT_EQ(0, syscall(__NR_cap_rights_limit, fd, &rights, 0, 0, NULL, 0));
// Directly access the syscall, and find all unseemly manner of use for it.
// - Invalid flags
EXPECT_EQ(-1, syscall(__NR_cap_rights_limit, fd, &rights, 0, 0, NULL, 1));
EXPECT_EQ(EINVAL, errno);
// - Specify an fcntl subright, but no CAP_FCNTL set
EXPECT_EQ(-1, syscall(__NR_cap_rights_limit, fd, &rights, CAP_FCNTL_GETFL, 0, NULL, 0));
EXPECT_EQ(EINVAL, errno);
// - Specify an ioctl subright, but no CAP_IOCTL set
unsigned int ioctl1 = 1;
EXPECT_EQ(-1, syscall(__NR_cap_rights_limit, fd, &rights, 0, 1, &ioctl1, 0));
EXPECT_EQ(EINVAL, errno);
// - N ioctls, but null pointer passed
EXPECT_EQ(-1, syscall(__NR_cap_rights_limit, fd, &rights, 0, 1, NULL, 0));
EXPECT_EQ(EINVAL, errno);
// - Invalid nioctls
EXPECT_EQ(-1, syscall(__NR_cap_rights_limit, fd, &rights, 0, -2, NULL, 0));
EXPECT_EQ(EINVAL, errno);
// - Null primary rights
EXPECT_EQ(-1, syscall(__NR_cap_rights_limit, fd, NULL, 0, 0, NULL, 0));
EXPECT_EQ(EFAULT, errno);
// - Invalid index bitmask
rights.cr_rights[0] |= 3ULL << 57;
EXPECT_EQ(-1, syscall(__NR_cap_rights_limit, fd, &rights, 0, 0, NULL, 0));
EXPECT_EQ(EINVAL, errno);
// - Invalid version
rights.cr_rights[0] |= 2ULL << 62;
EXPECT_EQ(-1, syscall(__NR_cap_rights_limit, fd, &rights, 0, 0, NULL, 0));
EXPECT_EQ(EINVAL, errno);
close(fd);
unlink(TmpFile("cap_invalid_rights"));
}
FORK_TEST_ON(Linux, OpenByHandleAt, TmpFile("cap_openbyhandle_testfile")) {
REQUIRE_ROOT();
int dir = open(tmpdir.c_str(), O_RDONLY);
EXPECT_OK(dir);
int fd = openat(dir, "cap_openbyhandle_testfile", O_RDWR|O_CREAT, 0644);
EXPECT_OK(fd);
const char* message = "Saved text";
EXPECT_OK(write(fd, message, strlen(message)));
close(fd);
struct file_handle* fhandle = (struct file_handle*)malloc(sizeof(struct file_handle) + MAX_HANDLE_SZ);
fhandle->handle_bytes = MAX_HANDLE_SZ;
int mount_id;
EXPECT_OK(name_to_handle_at(dir, "cap_openbyhandle_testfile", fhandle, &mount_id, 0));
fd = open_by_handle_at(dir, fhandle, O_RDONLY);
EXPECT_OK(fd);
char buffer[200];
EXPECT_OK(read(fd, buffer, 199));
EXPECT_EQ(std::string(message), std::string(buffer));
close(fd);
// Cannot issue open_by_handle_at after entering capability mode.
cap_enter();
EXPECT_CAPMODE(open_by_handle_at(dir, fhandle, O_RDONLY));
close(dir);
}
int getrandom_(void *buf, size_t buflen, unsigned int flags) {
#ifdef __NR_getrandom
return syscall(__NR_getrandom, buf, buflen, flags);
#else
errno = ENOSYS;
return -1;
#endif
}
#if LINUX_VERSION_CODE >= KERNEL_VERSION(3, 17, 0)
#include <linux/random.h> // Requires 3.17 kernel
FORK_TEST(Linux, GetRandom) {
EXPECT_OK(cap_enter());
unsigned char buffer[1024];
unsigned char buffer2[1024];
EXPECT_OK(getrandom_(buffer, sizeof(buffer), GRND_NONBLOCK));
EXPECT_OK(getrandom_(buffer2, sizeof(buffer2), GRND_NONBLOCK));
EXPECT_NE(0, memcmp(buffer, buffer2, sizeof(buffer)));
}
#endif
int memfd_create_(const char *name, unsigned int flags) {
#ifdef __NR_memfd_create
return syscall(__NR_memfd_create, name, flags);
#else
errno = ENOSYS;
return -1;
#endif
}
#if LINUX_VERSION_CODE >= KERNEL_VERSION(3, 17, 0)
#include <linux/memfd.h> // Requires 3.17 kernel
TEST(Linux, MemFDDeathTest) {
int memfd = memfd_create_("capsicum-test", MFD_ALLOW_SEALING);
if (memfd == -1 && errno == ENOSYS) {
TEST_SKIPPED("memfd_create(2) gives -ENOSYS");
return;
}
const int LEN = 16;
EXPECT_OK(ftruncate(memfd, LEN));
int memfd_ro = dup(memfd);
int memfd_rw = dup(memfd);
EXPECT_OK(memfd_ro);
EXPECT_OK(memfd_rw);
cap_rights_t rights;
EXPECT_OK(cap_rights_limit(memfd_ro, cap_rights_init(&rights, CAP_MMAP_R, CAP_FSTAT)));
EXPECT_OK(cap_rights_limit(memfd_rw, cap_rights_init(&rights, CAP_MMAP_RW, CAP_FCHMOD)));
unsigned char *p_ro = (unsigned char *)mmap(NULL, LEN, PROT_READ, MAP_SHARED, memfd_ro, 0);
EXPECT_NE((unsigned char *)MAP_FAILED, p_ro);
unsigned char *p_rw = (unsigned char *)mmap(NULL, LEN, PROT_READ|PROT_WRITE, MAP_SHARED, memfd_rw, 0);
EXPECT_NE((unsigned char *)MAP_FAILED, p_rw);
EXPECT_EQ(MAP_FAILED,
mmap(NULL, LEN, PROT_READ|PROT_WRITE, MAP_SHARED, memfd_ro, 0));
*p_rw = 42;
EXPECT_EQ(42, *p_ro);
EXPECT_DEATH(*p_ro = 42, "");
#ifndef F_ADD_SEALS
// Hack for when libc6 does not yet include the updated linux/fcntl.h from kernel 3.17
#define _F_LINUX_SPECIFIC_BASE F_SETLEASE
#define F_ADD_SEALS (_F_LINUX_SPECIFIC_BASE + 9)
#define F_GET_SEALS (_F_LINUX_SPECIFIC_BASE + 10)
#define F_SEAL_SEAL 0x0001 /* prevent further seals from being set */
#define F_SEAL_SHRINK 0x0002 /* prevent file from shrinking */
#define F_SEAL_GROW 0x0004 /* prevent file from growing */
#define F_SEAL_WRITE 0x0008 /* prevent writes */
#endif
// Reading the seal information requires CAP_FSTAT.
int seals = fcntl(memfd, F_GET_SEALS);
EXPECT_OK(seals);
if (verbose) fprintf(stderr, "seals are %08x on base fd\n", seals);
int seals_ro = fcntl(memfd_ro, F_GET_SEALS);
EXPECT_EQ(seals, seals_ro);
if (verbose) fprintf(stderr, "seals are %08x on read-only fd\n", seals_ro);
int seals_rw = fcntl(memfd_rw, F_GET_SEALS);
EXPECT_NOTCAPABLE(seals_rw);
// Fail to seal as a writable mapping exists.
EXPECT_EQ(-1, fcntl(memfd_rw, F_ADD_SEALS, F_SEAL_WRITE));
EXPECT_EQ(EBUSY, errno);
*p_rw = 42;
// Seal the rw version; need to unmap first.
munmap(p_rw, LEN);
munmap(p_ro, LEN);
EXPECT_OK(fcntl(memfd_rw, F_ADD_SEALS, F_SEAL_WRITE));
seals = fcntl(memfd, F_GET_SEALS);
EXPECT_OK(seals);
if (verbose) fprintf(stderr, "seals are %08x on base fd\n", seals);
seals_ro = fcntl(memfd_ro, F_GET_SEALS);
EXPECT_EQ(seals, seals_ro);
if (verbose) fprintf(stderr, "seals are %08x on read-only fd\n", seals_ro);
// Remove the CAP_FCHMOD right, can no longer add seals.
EXPECT_OK(cap_rights_limit(memfd_rw, cap_rights_init(&rights, CAP_MMAP_RW)));
EXPECT_NOTCAPABLE(fcntl(memfd_rw, F_ADD_SEALS, F_SEAL_WRITE));
close(memfd);
close(memfd_ro);
close(memfd_rw);
}
#endif
#else
void noop() {}
#endif