diff options
Diffstat (limited to 'tools/testing/selftests/seccomp/seccomp_bpf.c')
| -rw-r--r-- | tools/testing/selftests/seccomp/seccomp_bpf.c | 447 |
1 files changed, 445 insertions, 2 deletions
diff --git a/tools/testing/selftests/seccomp/seccomp_bpf.c b/tools/testing/selftests/seccomp/seccomp_bpf.c index c9a2abf8be1b..067cb4607d6c 100644 --- a/tools/testing/selftests/seccomp/seccomp_bpf.c +++ b/tools/testing/selftests/seccomp/seccomp_bpf.c @@ -5,6 +5,7 @@ * Test code for seccomp bpf. */ +#define _GNU_SOURCE #include <sys/types.h> /* @@ -40,10 +41,12 @@ #include <sys/fcntl.h> #include <sys/mman.h> #include <sys/times.h> +#include <sys/socket.h> +#include <sys/ioctl.h> -#define _GNU_SOURCE #include <unistd.h> #include <sys/syscall.h> +#include <poll.h> #include "../kselftest_harness.h" @@ -133,6 +136,10 @@ struct seccomp_data { #define SECCOMP_GET_ACTION_AVAIL 2 #endif +#ifndef SECCOMP_GET_NOTIF_SIZES +#define SECCOMP_GET_NOTIF_SIZES 3 +#endif + #ifndef SECCOMP_FILTER_FLAG_TSYNC #define SECCOMP_FILTER_FLAG_TSYNC (1UL << 0) #endif @@ -154,6 +161,44 @@ struct seccomp_metadata { }; #endif +#ifndef SECCOMP_FILTER_FLAG_NEW_LISTENER +#define SECCOMP_FILTER_FLAG_NEW_LISTENER (1UL << 3) + +#define SECCOMP_RET_USER_NOTIF 0x7fc00000U + +#define SECCOMP_IOC_MAGIC '!' +#define SECCOMP_IO(nr) _IO(SECCOMP_IOC_MAGIC, nr) +#define SECCOMP_IOR(nr, type) _IOR(SECCOMP_IOC_MAGIC, nr, type) +#define SECCOMP_IOW(nr, type) _IOW(SECCOMP_IOC_MAGIC, nr, type) +#define SECCOMP_IOWR(nr, type) _IOWR(SECCOMP_IOC_MAGIC, nr, type) + +/* Flags for seccomp notification fd ioctl. */ +#define SECCOMP_IOCTL_NOTIF_RECV SECCOMP_IOWR(0, struct seccomp_notif) +#define SECCOMP_IOCTL_NOTIF_SEND SECCOMP_IOWR(1, \ + struct seccomp_notif_resp) +#define SECCOMP_IOCTL_NOTIF_ID_VALID SECCOMP_IOR(2, __u64) + +struct seccomp_notif { + __u64 id; + __u32 pid; + __u32 flags; + struct seccomp_data data; +}; + +struct seccomp_notif_resp { + __u64 id; + __s64 val; + __s32 error; + __u32 flags; +}; + +struct seccomp_notif_sizes { + __u16 seccomp_notif; + __u16 seccomp_notif_resp; + __u16 seccomp_data; +}; +#endif + #ifndef seccomp int seccomp(unsigned int op, unsigned int flags, void *args) { @@ -2077,7 +2122,8 @@ TEST(detect_seccomp_filter_flags) { unsigned int flags[] = { SECCOMP_FILTER_FLAG_TSYNC, SECCOMP_FILTER_FLAG_LOG, - SECCOMP_FILTER_FLAG_SPEC_ALLOW }; + SECCOMP_FILTER_FLAG_SPEC_ALLOW, + SECCOMP_FILTER_FLAG_NEW_LISTENER }; unsigned int flag, all_flags; int i; long ret; @@ -2938,6 +2984,403 @@ skip: ASSERT_EQ(0, kill(pid, SIGKILL)); } +static int user_trap_syscall(int nr, unsigned int flags) +{ + struct sock_filter filter[] = { + BPF_STMT(BPF_LD+BPF_W+BPF_ABS, + offsetof(struct seccomp_data, nr)), + BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, nr, 0, 1), + BPF_STMT(BPF_RET+BPF_K, SECCOMP_RET_USER_NOTIF), + BPF_STMT(BPF_RET+BPF_K, SECCOMP_RET_ALLOW), + }; + + struct sock_fprog prog = { + .len = (unsigned short)ARRAY_SIZE(filter), + .filter = filter, + }; + + return seccomp(SECCOMP_SET_MODE_FILTER, flags, &prog); +} + +#define USER_NOTIF_MAGIC 116983961184613L +TEST(user_notification_basic) +{ + pid_t pid; + long ret; + int status, listener; + struct seccomp_notif req = {}; + struct seccomp_notif_resp resp = {}; + struct pollfd pollfd; + + struct sock_filter filter[] = { + BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), + }; + struct sock_fprog prog = { + .len = (unsigned short)ARRAY_SIZE(filter), + .filter = filter, + }; + + pid = fork(); + ASSERT_GE(pid, 0); + + /* Check that we get -ENOSYS with no listener attached */ + if (pid == 0) { + if (user_trap_syscall(__NR_getpid, 0) < 0) + exit(1); + ret = syscall(__NR_getpid); + exit(ret >= 0 || errno != ENOSYS); + } + + EXPECT_EQ(waitpid(pid, &status, 0), pid); + EXPECT_EQ(true, WIFEXITED(status)); + EXPECT_EQ(0, WEXITSTATUS(status)); + + /* Add some no-op filters so for grins. */ + EXPECT_EQ(seccomp(SECCOMP_SET_MODE_FILTER, 0, &prog), 0); + EXPECT_EQ(seccomp(SECCOMP_SET_MODE_FILTER, 0, &prog), 0); + EXPECT_EQ(seccomp(SECCOMP_SET_MODE_FILTER, 0, &prog), 0); + EXPECT_EQ(seccomp(SECCOMP_SET_MODE_FILTER, 0, &prog), 0); + + /* Check that the basic notification machinery works */ + listener = user_trap_syscall(__NR_getpid, + SECCOMP_FILTER_FLAG_NEW_LISTENER); + EXPECT_GE(listener, 0); + + /* Installing a second listener in the chain should EBUSY */ + EXPECT_EQ(user_trap_syscall(__NR_getpid, + SECCOMP_FILTER_FLAG_NEW_LISTENER), + -1); + EXPECT_EQ(errno, EBUSY); + + pid = fork(); + ASSERT_GE(pid, 0); + + if (pid == 0) { + ret = syscall(__NR_getpid); + exit(ret != USER_NOTIF_MAGIC); + } + + pollfd.fd = listener; + pollfd.events = POLLIN | POLLOUT; + + EXPECT_GT(poll(&pollfd, 1, -1), 0); + EXPECT_EQ(pollfd.revents, POLLIN); + + EXPECT_EQ(ioctl(listener, SECCOMP_IOCTL_NOTIF_RECV, &req), 0); + + pollfd.fd = listener; + pollfd.events = POLLIN | POLLOUT; + + EXPECT_GT(poll(&pollfd, 1, -1), 0); + EXPECT_EQ(pollfd.revents, POLLOUT); + + EXPECT_EQ(req.data.nr, __NR_getpid); + + resp.id = req.id; + resp.error = 0; + resp.val = USER_NOTIF_MAGIC; + + /* check that we make sure flags == 0 */ + resp.flags = 1; + EXPECT_EQ(ioctl(listener, SECCOMP_IOCTL_NOTIF_SEND, &resp), -1); + EXPECT_EQ(errno, EINVAL); + + resp.flags = 0; + EXPECT_EQ(ioctl(listener, SECCOMP_IOCTL_NOTIF_SEND, &resp), 0); + + EXPECT_EQ(waitpid(pid, &status, 0), pid); + EXPECT_EQ(true, WIFEXITED(status)); + EXPECT_EQ(0, WEXITSTATUS(status)); +} + +TEST(user_notification_kill_in_middle) +{ + pid_t pid; + long ret; + int listener; + struct seccomp_notif req = {}; + struct seccomp_notif_resp resp = {}; + + listener = user_trap_syscall(__NR_getpid, + SECCOMP_FILTER_FLAG_NEW_LISTENER); + EXPECT_GE(listener, 0); + + /* + * Check that nothing bad happens when we kill the task in the middle + * of a syscall. + */ + pid = fork(); + ASSERT_GE(pid, 0); + + if (pid == 0) { + ret = syscall(__NR_getpid); + exit(ret != USER_NOTIF_MAGIC); + } + + EXPECT_EQ(ioctl(listener, SECCOMP_IOCTL_NOTIF_RECV, &req), 0); + EXPECT_EQ(ioctl(listener, SECCOMP_IOCTL_NOTIF_ID_VALID, &req.id), 0); + + EXPECT_EQ(kill(pid, SIGKILL), 0); + EXPECT_EQ(waitpid(pid, NULL, 0), pid); + + EXPECT_EQ(ioctl(listener, SECCOMP_IOCTL_NOTIF_ID_VALID, &req.id), -1); + + resp.id = req.id; + ret = ioctl(listener, SECCOMP_IOCTL_NOTIF_SEND, &resp); + EXPECT_EQ(ret, -1); + EXPECT_EQ(errno, ENOENT); +} + +static int handled = -1; + +static void signal_handler(int signal) +{ + if (write(handled, "c", 1) != 1) + perror("write from signal"); +} + +TEST(user_notification_signal) +{ + pid_t pid; + long ret; + int status, listener, sk_pair[2]; + struct seccomp_notif req = {}; + struct seccomp_notif_resp resp = {}; + char c; + + ASSERT_EQ(socketpair(PF_LOCAL, SOCK_SEQPACKET, 0, sk_pair), 0); + + listener = user_trap_syscall(__NR_gettid, + SECCOMP_FILTER_FLAG_NEW_LISTENER); + EXPECT_GE(listener, 0); + + pid = fork(); + ASSERT_GE(pid, 0); + + if (pid == 0) { + close(sk_pair[0]); + handled = sk_pair[1]; + if (signal(SIGUSR1, signal_handler) == SIG_ERR) { + perror("signal"); + exit(1); + } + /* + * ERESTARTSYS behavior is a bit hard to test, because we need + * to rely on a signal that has not yet been handled. Let's at + * least check that the error code gets propagated through, and + * hope that it doesn't break when there is actually a signal :) + */ + ret = syscall(__NR_gettid); + exit(!(ret == -1 && errno == 512)); + } + + close(sk_pair[1]); + + EXPECT_EQ(ioctl(listener, SECCOMP_IOCTL_NOTIF_RECV, &req), 0); + + EXPECT_EQ(kill(pid, SIGUSR1), 0); + + /* + * Make sure the signal really is delivered, which means we're not + * stuck in the user notification code any more and the notification + * should be dead. + */ + EXPECT_EQ(read(sk_pair[0], &c, 1), 1); + + resp.id = req.id; + resp.error = -EPERM; + resp.val = 0; + + EXPECT_EQ(ioctl(listener, SECCOMP_IOCTL_NOTIF_SEND, &resp), -1); + EXPECT_EQ(errno, ENOENT); + + EXPECT_EQ(ioctl(listener, SECCOMP_IOCTL_NOTIF_RECV, &req), 0); + + resp.id = req.id; + resp.error = -512; /* -ERESTARTSYS */ + resp.val = 0; + + EXPECT_EQ(ioctl(listener, SECCOMP_IOCTL_NOTIF_SEND, &resp), 0); + + EXPECT_EQ(waitpid(pid, &status, 0), pid); + EXPECT_EQ(true, WIFEXITED(status)); + EXPECT_EQ(0, WEXITSTATUS(status)); +} + +TEST(user_notification_closed_listener) +{ + pid_t pid; + long ret; + int status, listener; + + listener = user_trap_syscall(__NR_getpid, + SECCOMP_FILTER_FLAG_NEW_LISTENER); + EXPECT_GE(listener, 0); + + /* + * Check that we get an ENOSYS when the listener is closed. + */ + pid = fork(); + ASSERT_GE(pid, 0); + if (pid == 0) { + close(listener); + ret = syscall(__NR_getpid); + exit(ret != -1 && errno != ENOSYS); + } + + close(listener); + + EXPECT_EQ(waitpid(pid, &status, 0), pid); + EXPECT_EQ(true, WIFEXITED(status)); + EXPECT_EQ(0, WEXITSTATUS(status)); +} + +/* + * Check that a pid in a child namespace still shows up as valid in ours. + */ +TEST(user_notification_child_pid_ns) +{ + pid_t pid; + int status, listener; + struct seccomp_notif req = {}; + struct seccomp_notif_resp resp = {}; + + ASSERT_EQ(unshare(CLONE_NEWPID), 0); + + listener = user_trap_syscall(__NR_getpid, SECCOMP_FILTER_FLAG_NEW_LISTENER); + ASSERT_GE(listener, 0); + + pid = fork(); + ASSERT_GE(pid, 0); + + if (pid == 0) + exit(syscall(__NR_getpid) != USER_NOTIF_MAGIC); + + EXPECT_EQ(ioctl(listener, SECCOMP_IOCTL_NOTIF_RECV, &req), 0); + EXPECT_EQ(req.pid, pid); + + resp.id = req.id; + resp.error = 0; + resp.val = USER_NOTIF_MAGIC; + + EXPECT_EQ(ioctl(listener, SECCOMP_IOCTL_NOTIF_SEND, &resp), 0); + + EXPECT_EQ(waitpid(pid, &status, 0), pid); + EXPECT_EQ(true, WIFEXITED(status)); + EXPECT_EQ(0, WEXITSTATUS(status)); + close(listener); +} + +/* + * Check that a pid in a sibling (i.e. unrelated) namespace shows up as 0, i.e. + * invalid. + */ +TEST(user_notification_sibling_pid_ns) +{ + pid_t pid, pid2; + int status, listener; + struct seccomp_notif req = {}; + struct seccomp_notif_resp resp = {}; + + listener = user_trap_syscall(__NR_getpid, SECCOMP_FILTER_FLAG_NEW_LISTENER); + ASSERT_GE(listener, 0); + + pid = fork(); + ASSERT_GE(pid, 0); + + if (pid == 0) { + ASSERT_EQ(unshare(CLONE_NEWPID), 0); + + pid2 = fork(); + ASSERT_GE(pid2, 0); + + if (pid2 == 0) + exit(syscall(__NR_getpid) != USER_NOTIF_MAGIC); + + EXPECT_EQ(waitpid(pid2, &status, 0), pid2); + EXPECT_EQ(true, WIFEXITED(status)); + EXPECT_EQ(0, WEXITSTATUS(status)); + exit(WEXITSTATUS(status)); + } + + /* Create the sibling ns, and sibling in it. */ + EXPECT_EQ(unshare(CLONE_NEWPID), 0); + EXPECT_EQ(errno, 0); + + pid2 = fork(); + EXPECT_GE(pid2, 0); + + if (pid2 == 0) { + ASSERT_EQ(ioctl(listener, SECCOMP_IOCTL_NOTIF_RECV, &req), 0); + /* + * The pid should be 0, i.e. the task is in some namespace that + * we can't "see". + */ + ASSERT_EQ(req.pid, 0); + + resp.id = req.id; + resp.error = 0; + resp.val = USER_NOTIF_MAGIC; + + ASSERT_EQ(ioctl(listener, SECCOMP_IOCTL_NOTIF_SEND, &resp), 0); + exit(0); + } + + close(listener); + + EXPECT_EQ(waitpid(pid, &status, 0), pid); + EXPECT_EQ(true, WIFEXITED(status)); + EXPECT_EQ(0, WEXITSTATUS(status)); + + EXPECT_EQ(waitpid(pid2, &status, 0), pid2); + EXPECT_EQ(true, WIFEXITED(status)); + EXPECT_EQ(0, WEXITSTATUS(status)); +} + +TEST(user_notification_fault_recv) +{ + pid_t pid; + int status, listener; + struct seccomp_notif req = {}; + struct seccomp_notif_resp resp = {}; + + listener = user_trap_syscall(__NR_getpid, SECCOMP_FILTER_FLAG_NEW_LISTENER); + ASSERT_GE(listener, 0); + + pid = fork(); + ASSERT_GE(pid, 0); + + if (pid == 0) + exit(syscall(__NR_getpid) != USER_NOTIF_MAGIC); + + /* Do a bad recv() */ + EXPECT_EQ(ioctl(listener, SECCOMP_IOCTL_NOTIF_RECV, NULL), -1); + EXPECT_EQ(errno, EFAULT); + + /* We should still be able to receive this notification, though. */ + EXPECT_EQ(ioctl(listener, SECCOMP_IOCTL_NOTIF_RECV, &req), 0); + EXPECT_EQ(req.pid, pid); + + resp.id = req.id; + resp.error = 0; + resp.val = USER_NOTIF_MAGIC; + + EXPECT_EQ(ioctl(listener, SECCOMP_IOCTL_NOTIF_SEND, &resp), 0); + + EXPECT_EQ(waitpid(pid, &status, 0), pid); + EXPECT_EQ(true, WIFEXITED(status)); + EXPECT_EQ(0, WEXITSTATUS(status)); +} + +TEST(seccomp_get_notif_sizes) +{ + struct seccomp_notif_sizes sizes; + + EXPECT_EQ(seccomp(SECCOMP_GET_NOTIF_SIZES, 0, &sizes), 0); + EXPECT_EQ(sizes.seccomp_notif, sizeof(struct seccomp_notif)); + EXPECT_EQ(sizes.seccomp_notif_resp, sizeof(struct seccomp_notif_resp)); +} + /* * TODO: * - add microbenchmarks |