@@ -45,6 +45,7 @@
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <linux/kcmp.h>
+#include <sys/resource.h>
#include <unistd.h>
#include <sys/syscall.h>
@@ -168,7 +169,9 @@ struct seccomp_metadata {
#ifndef SECCOMP_FILTER_FLAG_NEW_LISTENER
#define SECCOMP_FILTER_FLAG_NEW_LISTENER (1UL << 3)
+#endif
+#ifndef SECCOMP_RET_USER_NOTIF
#define SECCOMP_RET_USER_NOTIF 0x7fc00000U
#define SECCOMP_IOC_MAGIC '!'
@@ -204,6 +207,39 @@ struct seccomp_notif_sizes {
};
#endif
+#ifndef SECCOMP_IOCTL_NOTIF_ADDFD
+/* On success, the return value is the remote process's added fd number */
+#define SECCOMP_IOCTL_NOTIF_ADDFD SECCOMP_IOW(3, \
+ struct seccomp_notif_addfd)
+
+/* valid flags for seccomp_notif_addfd */
+#define SECCOMP_ADDFD_FLAG_SETFD (1UL << 0) /* Specify remote fd */
+
+struct seccomp_notif_addfd {
+ __u64 id;
+ __u32 flags;
+ __u32 srcfd;
+ __u32 newfd;
+ __u32 newfd_flags;
+};
+#endif
+
+struct seccomp_notif_addfd_small {
+ __u64 id;
+ char weird[4];
+};
+#define SECCOMP_IOCTL_NOTIF_ADDFD_SMALL \
+ SECCOMP_IOW(3, struct seccomp_notif_addfd_small)
+
+struct seccomp_notif_addfd_big {
+ union {
+ struct seccomp_notif_addfd addfd;
+ char buf[sizeof(struct seccomp_notif_addfd) + 8];
+ };
+};
+#define SECCOMP_IOCTL_NOTIF_ADDFD_BIG \
+ SECCOMP_IOWR(3, struct seccomp_notif_addfd_big)
+
#ifndef PTRACE_EVENTMSG_SYSCALL_ENTRY
#define PTRACE_EVENTMSG_SYSCALL_ENTRY 1
#define PTRACE_EVENTMSG_SYSCALL_EXIT 2
@@ -3833,6 +3869,199 @@ TEST(user_notification_filter_empty_threaded)
EXPECT_GT((pollfd.revents & POLLHUP) ?: 0, 0);
}
+TEST(user_notification_addfd)
+{
+ pid_t pid;
+ long ret;
+ int status, listener, memfd, fd;
+ struct seccomp_notif_addfd addfd = {};
+ struct seccomp_notif_addfd_small small = {};
+ struct seccomp_notif_addfd_big big = {};
+ struct seccomp_notif req = {};
+ struct seccomp_notif_resp resp = {};
+ /* 100 ms */
+ struct timespec delay = { .tv_nsec = 100000000 };
+
+ memfd = memfd_create("test", 0);
+ ASSERT_GE(memfd, 0);
+
+ ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0);
+ ASSERT_EQ(0, ret) {
+ TH_LOG("Kernel does not support PR_SET_NO_NEW_PRIVS!");
+ }
+
+ /* Check that the basic notification machinery works */
+ listener = user_notif_syscall(__NR_getppid,
+ SECCOMP_FILTER_FLAG_NEW_LISTENER);
+ ASSERT_GE(listener, 0);
+
+ pid = fork();
+ ASSERT_GE(pid, 0);
+
+ if (pid == 0) {
+ if (syscall(__NR_getppid) != USER_NOTIF_MAGIC)
+ exit(1);
+ exit(syscall(__NR_getppid) != USER_NOTIF_MAGIC);
+ }
+
+ ASSERT_EQ(ioctl(listener, SECCOMP_IOCTL_NOTIF_RECV, &req), 0);
+
+ addfd.srcfd = memfd;
+ addfd.newfd = 0;
+ addfd.id = req.id;
+ addfd.flags = 0x0;
+
+ /* Verify bad newfd_flags cannot be set */
+ addfd.newfd_flags = ~O_CLOEXEC;
+ EXPECT_EQ(ioctl(listener, SECCOMP_IOCTL_NOTIF_ADDFD, &addfd), -1);
+ EXPECT_EQ(errno, EINVAL);
+ addfd.newfd_flags = O_CLOEXEC;
+
+ /* Verify bad flags cannot be set */
+ addfd.flags = 0xff;
+ EXPECT_EQ(ioctl(listener, SECCOMP_IOCTL_NOTIF_ADDFD, &addfd), -1);
+ EXPECT_EQ(errno, EINVAL);
+ addfd.flags = 0;
+
+ /* Verify that remote_fd cannot be set without setting flags */
+ addfd.newfd = 1;
+ EXPECT_EQ(ioctl(listener, SECCOMP_IOCTL_NOTIF_ADDFD, &addfd), -1);
+ EXPECT_EQ(errno, EINVAL);
+ addfd.newfd = 0;
+
+ /* Verify small size cannot be set */
+ EXPECT_EQ(ioctl(listener, SECCOMP_IOCTL_NOTIF_ADDFD_SMALL, &small), -1);
+ EXPECT_EQ(errno, EINVAL);
+
+ /* Verify we can't send bits filled in unknown buffer area */
+ memset(&big, 0xAA, sizeof(big));
+ big.addfd = addfd;
+ EXPECT_EQ(ioctl(listener, SECCOMP_IOCTL_NOTIF_ADDFD_BIG, &big), -1);
+ EXPECT_EQ(errno, E2BIG);
+
+
+ /* Verify we can set an arbitrary remote fd */
+ fd = ioctl(listener, SECCOMP_IOCTL_NOTIF_ADDFD, &addfd);
+ /*
+ * The child has fds 0(stdin), 1(stdout), 2(stderr), 3(memfd),
+ * 4(listener), so the newly allocated fd should be 5.
+ */
+ EXPECT_EQ(fd, 5);
+ EXPECT_EQ(filecmp(getpid(), pid, memfd, fd), 0);
+
+ /* Verify we can set an arbitrary remote fd with large size */
+ memset(&big, 0x0, sizeof(big));
+ big.addfd = addfd;
+ fd = ioctl(listener, SECCOMP_IOCTL_NOTIF_ADDFD_BIG, &big);
+ EXPECT_EQ(fd, 6);
+
+ /* Verify we can set a specific remote fd */
+ addfd.newfd = 42;
+ addfd.flags = SECCOMP_ADDFD_FLAG_SETFD;
+ fd = ioctl(listener, SECCOMP_IOCTL_NOTIF_ADDFD, &addfd);
+ EXPECT_EQ(fd, 42);
+ EXPECT_EQ(filecmp(getpid(), pid, memfd, fd), 0);
+
+ /* Resume syscall */
+ resp.id = req.id;
+ resp.error = 0;
+ resp.val = USER_NOTIF_MAGIC;
+ EXPECT_EQ(ioctl(listener, SECCOMP_IOCTL_NOTIF_SEND, &resp), 0);
+
+ /*
+ * This sets the ID of the ADD FD to the last request plus 1. The
+ * notification ID increments 1 per notification.
+ */
+ addfd.id = req.id + 1;
+
+ /* This spins until the underlying notification is generated */
+ while (ioctl(listener, SECCOMP_IOCTL_NOTIF_ADDFD, &addfd) != -1 &&
+ errno != -EINPROGRESS)
+ nanosleep(&delay, NULL);
+
+ memset(&req, 0, sizeof(req));
+ ASSERT_EQ(ioctl(listener, SECCOMP_IOCTL_NOTIF_RECV, &req), 0);
+ ASSERT_EQ(addfd.id, req.id);
+
+ resp.id = req.id;
+ resp.error = 0;
+ resp.val = USER_NOTIF_MAGIC;
+ EXPECT_EQ(ioctl(listener, SECCOMP_IOCTL_NOTIF_SEND, &resp), 0);
+
+ /* Wait for child to finish. */
+ EXPECT_EQ(waitpid(pid, &status, 0), pid);
+ EXPECT_EQ(true, WIFEXITED(status));
+ EXPECT_EQ(0, WEXITSTATUS(status));
+
+ close(memfd);
+}
+
+TEST(user_notification_addfd_rlimit)
+{
+ pid_t pid;
+ long ret;
+ int status, listener, memfd;
+ struct seccomp_notif_addfd addfd = {};
+ struct seccomp_notif req = {};
+ struct seccomp_notif_resp resp = {};
+ const struct rlimit lim = {
+ .rlim_cur = 0,
+ .rlim_max = 0,
+ };
+
+ memfd = memfd_create("test", 0);
+ ASSERT_GE(memfd, 0);
+
+ ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0);
+ ASSERT_EQ(0, ret) {
+ TH_LOG("Kernel does not support PR_SET_NO_NEW_PRIVS!");
+ }
+
+ /* Check that the basic notification machinery works */
+ listener = user_notif_syscall(__NR_getppid,
+ SECCOMP_FILTER_FLAG_NEW_LISTENER);
+ ASSERT_GE(listener, 0);
+
+ pid = fork();
+ ASSERT_GE(pid, 0);
+
+ if (pid == 0)
+ exit(syscall(__NR_getppid) != USER_NOTIF_MAGIC);
+
+
+ ASSERT_EQ(ioctl(listener, SECCOMP_IOCTL_NOTIF_RECV, &req), 0);
+
+ ASSERT_EQ(prlimit(pid, RLIMIT_NOFILE, &lim, NULL), 0);
+
+ addfd.srcfd = memfd;
+ addfd.newfd_flags = O_CLOEXEC;
+ addfd.newfd = 0;
+ addfd.id = req.id;
+ addfd.flags = 0;
+
+ /* Should probably spot check /proc/sys/fs/file-nr */
+ EXPECT_EQ(ioctl(listener, SECCOMP_IOCTL_NOTIF_ADDFD, &addfd), -1);
+ EXPECT_EQ(errno, EMFILE);
+
+ addfd.newfd = 100;
+ addfd.flags = SECCOMP_ADDFD_FLAG_SETFD;
+ EXPECT_EQ(ioctl(listener, SECCOMP_IOCTL_NOTIF_ADDFD, &addfd), -1);
+ EXPECT_EQ(errno, EBADF);
+
+ resp.id = req.id;
+ resp.error = 0;
+ resp.val = USER_NOTIF_MAGIC;
+
+ EXPECT_EQ(ioctl(listener, SECCOMP_IOCTL_NOTIF_SEND, &resp), 0);
+
+ /* Wait for child to finish. */
+ EXPECT_EQ(waitpid(pid, &status, 0), pid);
+ EXPECT_EQ(true, WIFEXITED(status));
+ EXPECT_EQ(0, WEXITSTATUS(status));
+
+ close(memfd);
+}
+
/*
* TODO:
* - expand NNP testing