mirror of
https://github.com/containers/youki
synced 2024-06-03 05:16:17 +02:00
545b13da86
Signed-off-by: yihuaf <yihuaf@unkies.org>
1083 lines
38 KiB
Rust
1083 lines
38 KiB
Rust
use super::args::{ContainerArgs, ContainerType};
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use crate::error::MissingSpecError;
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use crate::namespaces::NamespaceError;
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use crate::syscall::{Syscall, SyscallError};
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use crate::{apparmor, notify_socket, rootfs, workload};
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use crate::{
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capabilities, hooks, namespaces::Namespaces, process::channel, rootfs::RootFS,
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rootless::Rootless, tty, utils,
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};
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use nix::mount::MsFlags;
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use nix::sched::CloneFlags;
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use nix::sys::stat::Mode;
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use nix::unistd::setsid;
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use nix::unistd::{self, Gid, Uid};
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use oci_spec::runtime::{LinuxNamespaceType, Spec, User};
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use std::collections::HashMap;
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use std::os::unix::io::AsRawFd;
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use std::{
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env, fs,
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path::{Path, PathBuf},
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};
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#[cfg(feature = "libseccomp")]
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use crate::seccomp;
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#[derive(Debug, thiserror::Error)]
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pub enum InitProcessError {
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#[error("failed to set sysctl")]
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Sysctl(#[source] std::io::Error),
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#[error("failed to mount path as readonly")]
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MountPathReadonly(#[source] SyscallError),
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#[error("failed to mount path as masked")]
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MountPathMasked(#[source] SyscallError),
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#[error(transparent)]
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Namespaces(#[from] NamespaceError),
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#[error("failed to set hostname")]
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SetHostname(#[source] SyscallError),
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#[error("failed to set domainname")]
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SetDomainname(#[source] SyscallError),
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#[error("failed to reopen /dev/null")]
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ReopenDevNull(#[source] std::io::Error),
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#[error("failed to unix syscall")]
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NixOther(#[source] nix::Error),
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#[error(transparent)]
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MissingSpec(#[from] crate::error::MissingSpecError),
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#[error("failed to setup tty")]
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Tty(#[source] tty::TTYError),
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#[error("failed to run hooks")]
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Hooks(#[from] hooks::HookError),
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#[error("failed to prepare rootfs")]
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RootFS(#[source] rootfs::RootfsError),
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#[error("failed syscall")]
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SyscallOther(#[source] SyscallError),
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#[error("failed apparmor")]
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AppArmor(#[source] apparmor::AppArmorError),
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#[error("invalid umask")]
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InvalidUmask(u32),
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#[error(transparent)]
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#[cfg(feature = "libseccomp")]
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Seccomp(#[from] seccomp::SeccompError),
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#[error("invalid executable: {0}")]
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InvalidExecutable(String),
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#[error("io error")]
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Io(#[source] std::io::Error),
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#[error(transparent)]
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Channel(#[from] channel::ChannelError),
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#[error("setgroup is disabled")]
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SetGroupDisabled,
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#[error(transparent)]
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NotifyListener(#[from] notify_socket::NotifyListenerError),
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#[error(transparent)]
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Workload(#[from] workload::ExecutorManagerError),
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}
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type Result<T> = std::result::Result<T, InitProcessError>;
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fn get_executable_path(name: &str, path_var: &str) -> Option<PathBuf> {
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// if path has / in it, we have to assume absolute path, as per runc impl
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if name.contains('/') && PathBuf::from(name).exists() {
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return Some(PathBuf::from(name));
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}
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for path in path_var.split(':') {
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let potential_path = PathBuf::from(path).join(name);
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if potential_path.exists() {
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return Some(potential_path);
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}
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}
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None
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}
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fn is_executable(path: &Path) -> std::result::Result<bool, std::io::Error> {
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use std::os::unix::fs::PermissionsExt;
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let metadata = path.metadata()?;
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let permissions = metadata.permissions();
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// we have to check if the path is file and the execute bit
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// is set. In case of directories, the execute bit is also set,
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// so have to check if this is a file or not
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Ok(metadata.is_file() && permissions.mode() & 0o001 != 0)
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}
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// this checks if the binary to run actually exists and if we have
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// permissions to run it. Taken from
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// https://github.com/opencontainers/runc/blob/25c9e888686773e7e06429133578038a9abc091d/libcontainer/standard_init_linux.go#L195-L206
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fn verify_binary(args: &[String], envs: &[String]) -> Result<()> {
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let path_vars: Vec<&String> = envs.iter().filter(|&e| e.starts_with("PATH=")).collect();
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if path_vars.is_empty() {
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tracing::error!("PATH environment variable is not set");
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return Err(InitProcessError::InvalidExecutable(args[0].clone()));
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}
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let path_var = path_vars[0].trim_start_matches("PATH=");
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match get_executable_path(&args[0], path_var) {
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None => {
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tracing::error!(
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"executable {} for container process not found in PATH",
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args[0]
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);
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return Err(InitProcessError::InvalidExecutable(args[0].clone()));
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}
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Some(path) => match is_executable(&path) {
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Ok(true) => {
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tracing::debug!("found executable {:?}", path);
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}
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Ok(false) => {
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tracing::error!(
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"executable {:?} does not have the correct permission set",
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path
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);
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return Err(InitProcessError::InvalidExecutable(args[0].clone()));
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}
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Err(err) => {
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tracing::error!(
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"failed to check permissions for executable {:?}: {}",
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path,
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err
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);
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return Err(InitProcessError::Io(err));
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}
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},
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}
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Ok(())
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}
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fn sysctl(kernel_params: &HashMap<String, String>) -> Result<()> {
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let sys = PathBuf::from("/proc/sys");
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for (kernel_param, value) in kernel_params {
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let path = sys.join(kernel_param.replace('.', "/"));
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tracing::debug!(
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"apply value {} to kernel parameter {}.",
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value,
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kernel_param
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);
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fs::write(path, value.as_bytes()).map_err(|err| {
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tracing::error!("failed to set sysctl {kernel_param}={value}: {err}");
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InitProcessError::Sysctl(err)
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})?;
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}
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Ok(())
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}
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// make a read only path
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// The first time we bind mount, other flags are ignored,
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// so we need to mount it once and then remount it with the necessary flags specified.
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// https://man7.org/linux/man-pages/man2/mount.2.html
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fn readonly_path(path: &Path, syscall: &dyn Syscall) -> Result<()> {
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if let Err(err) = syscall.mount(
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Some(path),
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path,
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None,
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MsFlags::MS_BIND | MsFlags::MS_REC,
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None,
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) {
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if let SyscallError::Nix(errno) = err {
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// ignore error if path is not exist.
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if matches!(errno, nix::errno::Errno::ENOENT) {
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return Ok(());
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}
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}
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tracing::error!(?path, ?err, "failed to mount path as readonly");
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return Err(InitProcessError::MountPathReadonly(err));
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}
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syscall
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.mount(
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Some(path),
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path,
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None,
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MsFlags::MS_NOSUID
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| MsFlags::MS_NODEV
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| MsFlags::MS_NOEXEC
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| MsFlags::MS_BIND
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| MsFlags::MS_REMOUNT
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| MsFlags::MS_RDONLY,
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None,
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)
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.map_err(|err| {
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tracing::error!(?path, ?err, "failed to remount path as readonly");
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InitProcessError::MountPathReadonly(err)
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})?;
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tracing::debug!("readonly path {:?} mounted", path);
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Ok(())
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}
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// For files, bind mounts /dev/null over the top of the specified path.
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// For directories, mounts read-only tmpfs over the top of the specified path.
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fn masked_path(path: &Path, mount_label: &Option<String>, syscall: &dyn Syscall) -> Result<()> {
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if let Err(err) = syscall.mount(
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Some(Path::new("/dev/null")),
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path,
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None,
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MsFlags::MS_BIND,
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None,
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) {
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match err {
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SyscallError::Nix(nix::errno::Errno::ENOENT) => {
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// ignore error if path is not exist.
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}
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SyscallError::Nix(nix::errno::Errno::ENOTDIR) => {
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let label = match mount_label {
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Some(l) => format!("context=\"{l}\""),
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None => "".to_string(),
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};
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syscall
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.mount(
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Some(Path::new("tmpfs")),
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path,
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Some("tmpfs"),
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MsFlags::MS_RDONLY,
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Some(label.as_str()),
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)
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.map_err(|err| {
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tracing::error!(?path, ?err, "failed to mount path as masked using tempfs");
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InitProcessError::MountPathMasked(err)
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})?;
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}
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_ => {
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tracing::error!(
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?path,
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?err,
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"failed to mount path as masked using /dev/null"
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);
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return Err(InitProcessError::MountPathMasked(err));
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}
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}
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}
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Ok(())
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}
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// Enter into rest of namespace. Note, we already entered into user and pid
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// namespace. We also have to enter into mount namespace last since
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// namespace may be bind to /proc path. The /proc path will need to be
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// accessed before pivot_root.
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fn apply_rest_namespaces(
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namespaces: &Namespaces,
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spec: &Spec,
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syscall: &dyn Syscall,
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) -> Result<()> {
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namespaces
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.apply_namespaces(|ns_type| -> bool {
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ns_type != CloneFlags::CLONE_NEWUSER && ns_type != CloneFlags::CLONE_NEWPID
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})
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.map_err(|err| {
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tracing::error!(
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?err,
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"failed to apply rest of the namespaces (exclude user and pid)"
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);
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InitProcessError::Namespaces(err)
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})?;
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// Only set the host name if entering into a new uts namespace
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if let Some(uts_namespace) = namespaces.get(LinuxNamespaceType::Uts)? {
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if uts_namespace.path().is_none() {
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if let Some(hostname) = spec.hostname() {
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syscall.set_hostname(hostname).map_err(|err| {
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tracing::error!(?err, ?hostname, "failed to set hostname");
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InitProcessError::SetHostname(err)
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})?;
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}
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if let Some(domainname) = spec.domainname() {
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syscall.set_domainname(domainname).map_err(|err| {
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tracing::error!(?err, ?domainname, "failed to set domainname");
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InitProcessError::SetDomainname(err)
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})?;
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}
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}
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}
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Ok(())
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}
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fn reopen_dev_null() -> Result<()> {
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// At this point we should be inside of the container and now
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// we can re-open /dev/null if it is in use to the /dev/null
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// in the container.
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let dev_null = fs::File::open("/dev/null").map_err(|err| {
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tracing::error!(?err, "failed to open /dev/null inside the container");
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InitProcessError::ReopenDevNull(err)
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})?;
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let dev_null_fstat_info = nix::sys::stat::fstat(dev_null.as_raw_fd()).map_err(|err| {
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tracing::error!(?err, "failed to fstat /dev/null inside the container");
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InitProcessError::NixOther(err)
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})?;
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// Check if stdin, stdout or stderr point to /dev/null
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for fd in 0..3 {
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let fstat_info = nix::sys::stat::fstat(fd).map_err(|err| {
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tracing::error!(?err, "failed to fstat stdio fd {}", fd);
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InitProcessError::NixOther(err)
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})?;
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if dev_null_fstat_info.st_rdev == fstat_info.st_rdev {
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// This FD points to /dev/null outside of the container.
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// Let's point to /dev/null inside of the container.
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nix::unistd::dup2(dev_null.as_raw_fd(), fd).map_err(|err| {
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tracing::error!(?err, "failed to dup2 fd {} to /dev/null", fd);
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InitProcessError::NixOther(err)
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})?;
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}
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}
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Ok(())
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}
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// Some variables are unused in the case where libseccomp feature is not enabled.
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#[allow(unused_variables)]
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pub fn container_init_process(
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args: &ContainerArgs,
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main_sender: &mut channel::MainSender,
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init_receiver: &mut channel::InitReceiver,
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) -> Result<()> {
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let syscall = args.syscall;
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let spec = args.spec;
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let linux = spec.linux().as_ref().ok_or(MissingSpecError::Linux)?;
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let proc = spec.process().as_ref().ok_or(MissingSpecError::Process)?;
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let mut envs: Vec<String> = proc.env().as_ref().unwrap_or(&vec![]).clone();
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let rootfs_path = args.rootfs;
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let hooks = spec.hooks().as_ref();
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let container = args.container.as_ref();
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let namespaces = Namespaces::try_from(linux.namespaces().as_ref())?;
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setsid().map_err(|err| {
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tracing::error!(?err, "failed to setsid to create a session");
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InitProcessError::NixOther(err)
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})?;
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// set up tty if specified
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if let Some(csocketfd) = args.console_socket {
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tty::setup_console(&csocketfd).map_err(|err| {
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tracing::error!(?err, "failed to set up tty");
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InitProcessError::Tty(err)
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})?;
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}
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apply_rest_namespaces(&namespaces, spec, syscall)?;
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if let Some(true) = proc.no_new_privileges() {
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let _ = prctl::set_no_new_privileges(true);
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}
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if matches!(args.container_type, ContainerType::InitContainer) {
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// create_container hook needs to be called after the namespace setup, but
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// before pivot_root is called. This runs in the container namespaces.
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if let Some(hooks) = hooks {
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hooks::run_hooks(hooks.create_container().as_ref(), container).map_err(|err| {
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tracing::error!(?err, "failed to run create container hooks");
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InitProcessError::Hooks(err)
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})?;
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}
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let bind_service = namespaces.get(LinuxNamespaceType::User)?.is_some();
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let rootfs = RootFS::new();
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rootfs
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.prepare_rootfs(
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spec,
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rootfs_path,
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bind_service,
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namespaces.get(LinuxNamespaceType::Cgroup)?.is_some(),
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)
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.map_err(|err| {
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tracing::error!(?err, "failed to prepare rootfs");
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InitProcessError::RootFS(err)
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})?;
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|
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// Entering into the rootfs jail. If mount namespace is specified, then
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// we use pivot_root, but if we are on the host mount namespace, we will
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// use simple chroot. Scary things will happen if you try to pivot_root
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// in the host mount namespace...
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if namespaces.get(LinuxNamespaceType::Mount)?.is_some() {
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// change the root of filesystem of the process to the rootfs
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syscall.pivot_rootfs(rootfs_path).map_err(|err| {
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tracing::error!(?err, ?rootfs_path, "failed to pivot root");
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InitProcessError::SyscallOther(err)
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})?;
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} else {
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syscall.chroot(rootfs_path).map_err(|err| {
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tracing::error!(?err, ?rootfs_path, "failed to chroot");
|
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InitProcessError::SyscallOther(err)
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})?;
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}
|
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|
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rootfs.adjust_root_mount_propagation(linux).map_err(|err| {
|
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tracing::error!(?err, "failed to adjust root mount propagation");
|
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InitProcessError::RootFS(err)
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})?;
|
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|
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reopen_dev_null().map_err(|err| {
|
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tracing::error!(?err, "failed to reopen /dev/null");
|
|
err
|
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})?;
|
|
|
|
if let Some(kernel_params) = linux.sysctl() {
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sysctl(kernel_params)?;
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}
|
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}
|
|
|
|
if let Some(profile) = proc.apparmor_profile() {
|
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apparmor::apply_profile(profile).map_err(|err| {
|
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tracing::error!(?err, "failed to apply apparmor profile");
|
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InitProcessError::AppArmor(err)
|
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})?;
|
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}
|
|
|
|
if let Some(true) = spec.root().as_ref().map(|r| r.readonly().unwrap_or(false)) {
|
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syscall
|
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.mount(
|
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None,
|
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Path::new("/"),
|
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None,
|
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MsFlags::MS_RDONLY | MsFlags::MS_REMOUNT | MsFlags::MS_BIND,
|
|
None,
|
|
)
|
|
.map_err(|err| {
|
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tracing::error!(?err, "failed to remount root `/` as readonly");
|
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InitProcessError::SyscallOther(err)
|
|
})?;
|
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}
|
|
|
|
if let Some(umask) = proc.user().umask() {
|
|
match Mode::from_bits(umask) {
|
|
Some(mode) => {
|
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nix::sys::stat::umask(mode);
|
|
}
|
|
None => {
|
|
return Err(InitProcessError::InvalidUmask(umask));
|
|
}
|
|
}
|
|
}
|
|
|
|
if let Some(paths) = linux.readonly_paths() {
|
|
// mount readonly path
|
|
for path in paths {
|
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readonly_path(Path::new(path), syscall).map_err(|err| {
|
|
tracing::error!(?err, ?path, "failed to set readonly path");
|
|
err
|
|
})?;
|
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}
|
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}
|
|
|
|
if let Some(paths) = linux.masked_paths() {
|
|
// mount masked path
|
|
for path in paths {
|
|
masked_path(Path::new(path), linux.mount_label(), syscall).map_err(|err| {
|
|
tracing::error!(?err, ?path, "failed to set masked path");
|
|
err
|
|
})?;
|
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}
|
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}
|
|
|
|
let cwd = format!("{}", proc.cwd().display());
|
|
let do_chdir = if cwd.is_empty() {
|
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false
|
|
} else {
|
|
// This chdir must run before setting up the user.
|
|
// This may allow the user running youki to access directories
|
|
// that the container user cannot access.
|
|
match unistd::chdir(proc.cwd()) {
|
|
std::result::Result::Ok(_) => false,
|
|
Err(nix::Error::EPERM) => true,
|
|
Err(e) => {
|
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tracing::error!(?e, "failed to chdir");
|
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return Err(InitProcessError::NixOther(e));
|
|
}
|
|
}
|
|
};
|
|
|
|
set_supplementary_gids(proc.user(), args.rootless, syscall).map_err(|err| {
|
|
tracing::error!(?err, "failed to set supplementary gids");
|
|
err
|
|
})?;
|
|
|
|
syscall
|
|
.set_id(
|
|
Uid::from_raw(proc.user().uid()),
|
|
Gid::from_raw(proc.user().gid()),
|
|
)
|
|
.map_err(|err| {
|
|
let uid = proc.user().uid();
|
|
let gid = proc.user().gid();
|
|
tracing::error!(?err, ?uid, ?gid, "failed to set uid and gid");
|
|
InitProcessError::SyscallOther(err)
|
|
})?;
|
|
|
|
// Take care of LISTEN_FDS used for systemd-active-socket. If the value is
|
|
// not 0, then we have to preserve those fds as well, and set up the correct
|
|
// environment variables.
|
|
let preserve_fds: i32 = match env::var("LISTEN_FDS") {
|
|
std::result::Result::Ok(listen_fds_str) => {
|
|
let listen_fds = match listen_fds_str.parse::<i32>() {
|
|
std::result::Result::Ok(v) => v,
|
|
Err(error) => {
|
|
tracing::warn!(
|
|
"LISTEN_FDS entered is not a fd. Ignore the value. {:?}",
|
|
error
|
|
);
|
|
|
|
0
|
|
}
|
|
};
|
|
|
|
// The LISTEN_FDS will have to be passed to container init process.
|
|
// The LISTEN_PID will be set to PID 1. Based on the spec, if
|
|
// LISTEN_FDS is 0, the variable should be unset, so we just ignore
|
|
// it here, if it is 0.
|
|
if listen_fds > 0 {
|
|
envs.append(&mut vec![
|
|
format!("LISTEN_FDS={listen_fds}"),
|
|
"LISTEN_PID=1".to_string(),
|
|
]);
|
|
}
|
|
|
|
args.preserve_fds + listen_fds
|
|
}
|
|
Err(env::VarError::NotPresent) => args.preserve_fds,
|
|
Err(env::VarError::NotUnicode(value)) => {
|
|
tracing::warn!(
|
|
"LISTEN_FDS entered is malformed: {:?}. Ignore the value.",
|
|
&value
|
|
);
|
|
args.preserve_fds
|
|
}
|
|
};
|
|
|
|
// Cleanup any extra file descriptors, so the new container process will not
|
|
// leak a file descriptor from before execve gets executed. The first 3 fd will
|
|
// stay open: stdio, stdout, and stderr. We would further preserve the next
|
|
// "preserve_fds" number of fds. Set the rest of fd with CLOEXEC flag, so they
|
|
// will be closed after execve into the container payload. We can't close the
|
|
// fds immediately since we at least still need it for the pipe used to wait on
|
|
// starting the container.
|
|
syscall.close_range(preserve_fds).map_err(|err| {
|
|
tracing::error!(?err, "failed to cleanup extra fds");
|
|
InitProcessError::SyscallOther(err)
|
|
})?;
|
|
|
|
// Without no new privileges, seccomp is a privileged operation. We have to
|
|
// do this before dropping capabilities. Otherwise, we should do it later,
|
|
// as close to exec as possible.
|
|
#[cfg(feature = "libseccomp")]
|
|
if let Some(seccomp) = linux.seccomp() {
|
|
if proc.no_new_privileges().is_none() {
|
|
let notify_fd = seccomp::initialize_seccomp(seccomp).map_err(|err| {
|
|
tracing::error!(?err, "failed to initialize seccomp");
|
|
err
|
|
})?;
|
|
sync_seccomp(notify_fd, main_sender, init_receiver).map_err(|err| {
|
|
tracing::error!(?err, "failed to sync seccomp");
|
|
err
|
|
})?;
|
|
}
|
|
}
|
|
#[cfg(not(feature = "libseccomp"))]
|
|
if proc.no_new_privileges().is_none() {
|
|
tracing::warn!("seccomp not available, unable to enforce no_new_privileges!")
|
|
}
|
|
|
|
capabilities::reset_effective(syscall).map_err(|err| {
|
|
tracing::error!(?err, "failed to reset effective capabilities");
|
|
InitProcessError::SyscallOther(err)
|
|
})?;
|
|
if let Some(caps) = proc.capabilities() {
|
|
capabilities::drop_privileges(caps, syscall).map_err(|err| {
|
|
tracing::error!(?err, "failed to drop capabilities");
|
|
InitProcessError::SyscallOther(err)
|
|
})?;
|
|
}
|
|
|
|
// Change directory to process.cwd if process.cwd is not empty
|
|
if do_chdir {
|
|
unistd::chdir(proc.cwd()).map_err(|err| {
|
|
let cwd = proc.cwd();
|
|
tracing::error!(?err, ?cwd, "failed to chdir to cwd");
|
|
InitProcessError::NixOther(err)
|
|
})?;
|
|
}
|
|
|
|
// add HOME into envs if not exists
|
|
let home_in_envs = envs.iter().any(|x| x.starts_with("HOME="));
|
|
if !home_in_envs {
|
|
if let Some(dir_home) = utils::get_user_home(proc.user().uid()) {
|
|
envs.push(format!("HOME={}", dir_home.to_string_lossy()));
|
|
}
|
|
}
|
|
|
|
// Reset the process env based on oci spec.
|
|
env::vars().for_each(|(key, _value)| env::remove_var(key));
|
|
utils::parse_env(&envs)
|
|
.iter()
|
|
.for_each(|(key, value)| env::set_var(key, value));
|
|
|
|
// Initialize seccomp profile right before we are ready to execute the
|
|
// payload so as few syscalls will happen between here and payload exec. The
|
|
// notify socket will still need network related syscalls.
|
|
#[cfg(feature = "libseccomp")]
|
|
if let Some(seccomp) = linux.seccomp() {
|
|
if proc.no_new_privileges().is_some() {
|
|
let notify_fd = seccomp::initialize_seccomp(seccomp).map_err(|err| {
|
|
tracing::error!(?err, "failed to initialize seccomp");
|
|
err
|
|
})?;
|
|
sync_seccomp(notify_fd, main_sender, init_receiver).map_err(|err| {
|
|
tracing::error!(?err, "failed to sync seccomp");
|
|
err
|
|
})?;
|
|
}
|
|
}
|
|
#[cfg(not(feature = "libseccomp"))]
|
|
if proc.no_new_privileges().is_some() {
|
|
tracing::warn!("seccomp not available, unable to set seccomp privileges!")
|
|
}
|
|
|
|
if let Some(args) = proc.args() {
|
|
verify_binary(args, &envs)?;
|
|
}
|
|
|
|
// Notify main process that the init process is ready to execute the
|
|
// payload. Note, because we are already inside the pid namespace, the pid
|
|
// outside the pid namespace should be recorded by the intermediate process
|
|
// already.
|
|
main_sender.init_ready().map_err(|err| {
|
|
tracing::error!(
|
|
?err,
|
|
"failed to notify main process that init process is ready"
|
|
);
|
|
InitProcessError::Channel(err)
|
|
})?;
|
|
main_sender.close().map_err(|err| {
|
|
tracing::error!(?err, "failed to close down main sender in init process");
|
|
InitProcessError::Channel(err)
|
|
})?;
|
|
|
|
// listing on the notify socket for container start command
|
|
args.notify_socket
|
|
.wait_for_container_start()
|
|
.map_err(|err| {
|
|
tracing::error!(?err, "failed to wait for container start");
|
|
err
|
|
})?;
|
|
args.notify_socket.close().map_err(|err| {
|
|
tracing::error!(?err, "failed to close notify socket");
|
|
err
|
|
})?;
|
|
|
|
// create_container hook needs to be called after the namespace setup, but
|
|
// before pivot_root is called. This runs in the container namespaces.
|
|
if matches!(args.container_type, ContainerType::InitContainer) {
|
|
if let Some(hooks) = hooks {
|
|
hooks::run_hooks(hooks.start_container().as_ref(), container).map_err(|err| {
|
|
tracing::error!(?err, "failed to run start container hooks");
|
|
err
|
|
})?;
|
|
}
|
|
}
|
|
|
|
if proc.args().is_some() {
|
|
args.executor_manager.exec(spec).map_err(|err| {
|
|
tracing::error!(?err, "failed to execute payload");
|
|
err
|
|
})?;
|
|
unreachable!("should not be back here");
|
|
} else {
|
|
tracing::error!("on non-Windows, at least one process arg entry is required");
|
|
Err(MissingSpecError::Args)
|
|
}?
|
|
}
|
|
|
|
// Before 3.19 it was possible for an unprivileged user to enter an user namespace,
|
|
// become root and then call setgroups in order to drop membership in supplementary
|
|
// groups. This allowed access to files which blocked access based on being a member
|
|
// of these groups (see CVE-2014-8989)
|
|
//
|
|
// This leaves us with three scenarios:
|
|
//
|
|
// Unprivileged user starting a rootless container: The main process is running as an
|
|
// unprivileged user and therefore cannot write the mapping until "deny" has been written
|
|
// to /proc/{pid}/setgroups. Once written /proc/{pid}/setgroups cannot be reset and the
|
|
// setgroups system call will be disabled for all processes in this user namespace. This
|
|
// also means that we should detect if the user is unprivileged and additional gids have
|
|
// been specified and bail out early as this can never work. This is not handled here,
|
|
// but during the validation for rootless containers.
|
|
//
|
|
// Privileged user starting a rootless container: It is not necessary to write "deny" to
|
|
// /proc/setgroups in order to create the gid mapping and therefore we don't. This means
|
|
// that setgroups could be used to drop groups, but this is fine as the user is privileged
|
|
// and could do so anyway.
|
|
// We already have checked during validation if the specified supplemental groups fall into
|
|
// the range that are specified in the gid mapping and bail out early if they do not.
|
|
//
|
|
// Privileged user starting a normal container: Just add the supplementary groups.
|
|
//
|
|
fn set_supplementary_gids(
|
|
user: &User,
|
|
rootless: &Option<Rootless>,
|
|
syscall: &dyn Syscall,
|
|
) -> Result<()> {
|
|
if let Some(additional_gids) = user.additional_gids() {
|
|
if additional_gids.is_empty() {
|
|
return Ok(());
|
|
}
|
|
|
|
let setgroups = fs::read_to_string("/proc/self/setgroups").map_err(|err| {
|
|
tracing::error!(?err, "failed to read setgroups");
|
|
InitProcessError::Io(err)
|
|
})?;
|
|
if setgroups.trim() == "deny" {
|
|
tracing::error!("cannot set supplementary gids, setgroup is disabled");
|
|
return Err(InitProcessError::SetGroupDisabled);
|
|
}
|
|
|
|
let gids: Vec<Gid> = additional_gids
|
|
.iter()
|
|
.map(|gid| Gid::from_raw(*gid))
|
|
.collect();
|
|
|
|
match rootless {
|
|
Some(r) if r.privileged => {
|
|
syscall.set_groups(&gids).map_err(|err| {
|
|
tracing::error!(?err, ?gids, "failed to set privileged supplementary gids");
|
|
InitProcessError::SyscallOther(err)
|
|
})?;
|
|
}
|
|
None => {
|
|
syscall.set_groups(&gids).map_err(|err| {
|
|
tracing::error!(?err, ?gids, "failed to set unprivileged supplementary gids");
|
|
InitProcessError::SyscallOther(err)
|
|
})?;
|
|
}
|
|
// this should have been detected during validation
|
|
_ => unreachable!(
|
|
"unprivileged users cannot set supplementary gids in rootless container"
|
|
),
|
|
}
|
|
}
|
|
|
|
Ok(())
|
|
}
|
|
|
|
#[cfg(feature = "libseccomp")]
|
|
fn sync_seccomp(
|
|
fd: Option<i32>,
|
|
main_sender: &mut channel::MainSender,
|
|
init_receiver: &mut channel::InitReceiver,
|
|
) -> Result<()> {
|
|
if let Some(fd) = fd {
|
|
tracing::debug!("init process sync seccomp, notify fd: {}", fd);
|
|
main_sender.seccomp_notify_request(fd).map_err(|err| {
|
|
tracing::error!(?err, "failed to send seccomp notify request");
|
|
InitProcessError::Channel(err)
|
|
})?;
|
|
init_receiver
|
|
.wait_for_seccomp_request_done()
|
|
.map_err(|err| {
|
|
tracing::error!(?err, "failed to wait for seccomp request done");
|
|
InitProcessError::Channel(err)
|
|
})?;
|
|
// Once we are sure the seccomp notify fd is sent, we can safely close
|
|
// it. The fd is now duplicated to the main process and sent to seccomp
|
|
// listener.
|
|
let _ = unistd::close(fd);
|
|
}
|
|
|
|
Ok(())
|
|
}
|
|
|
|
#[cfg(test)]
|
|
mod tests {
|
|
use super::*;
|
|
use crate::syscall::{
|
|
syscall::create_syscall,
|
|
test::{ArgName, MountArgs, TestHelperSyscall},
|
|
};
|
|
use anyhow::Result;
|
|
#[cfg(feature = "libseccomp")]
|
|
use nix::unistd;
|
|
use oci_spec::runtime::{LinuxNamespaceBuilder, SpecBuilder, UserBuilder};
|
|
#[cfg(feature = "libseccomp")]
|
|
use serial_test::serial;
|
|
use std::fs;
|
|
|
|
#[test]
|
|
fn test_readonly_path() -> Result<()> {
|
|
let syscall = create_syscall();
|
|
readonly_path(Path::new("/proc/sys"), syscall.as_ref())?;
|
|
|
|
let want = vec![
|
|
MountArgs {
|
|
source: Some(PathBuf::from("/proc/sys")),
|
|
target: PathBuf::from("/proc/sys"),
|
|
fstype: None,
|
|
flags: MsFlags::MS_BIND | MsFlags::MS_REC,
|
|
data: None,
|
|
},
|
|
MountArgs {
|
|
source: Some(PathBuf::from("/proc/sys")),
|
|
target: PathBuf::from("/proc/sys"),
|
|
fstype: None,
|
|
flags: MsFlags::MS_NOSUID
|
|
| MsFlags::MS_NODEV
|
|
| MsFlags::MS_NOEXEC
|
|
| MsFlags::MS_BIND
|
|
| MsFlags::MS_REMOUNT
|
|
| MsFlags::MS_RDONLY,
|
|
data: None,
|
|
},
|
|
];
|
|
let got = syscall
|
|
.as_any()
|
|
.downcast_ref::<TestHelperSyscall>()
|
|
.unwrap()
|
|
.get_mount_args();
|
|
|
|
assert_eq!(want, *got);
|
|
assert_eq!(got.len(), 2);
|
|
Ok(())
|
|
}
|
|
|
|
#[test]
|
|
fn test_apply_rest_namespaces() -> Result<()> {
|
|
let syscall = create_syscall();
|
|
let spec = SpecBuilder::default().build()?;
|
|
let linux_spaces = vec![
|
|
LinuxNamespaceBuilder::default()
|
|
.typ(LinuxNamespaceType::Uts)
|
|
.build()?,
|
|
LinuxNamespaceBuilder::default()
|
|
.typ(LinuxNamespaceType::Pid)
|
|
.build()?,
|
|
];
|
|
let namespaces = Namespaces::try_from(Some(&linux_spaces))?;
|
|
|
|
apply_rest_namespaces(&namespaces, &spec, syscall.as_ref())?;
|
|
|
|
let got_hostnames = syscall
|
|
.as_ref()
|
|
.as_any()
|
|
.downcast_ref::<TestHelperSyscall>()
|
|
.unwrap()
|
|
.get_hostname_args();
|
|
assert_eq!(1, got_hostnames.len());
|
|
assert_eq!("youki".to_string(), got_hostnames[0]);
|
|
|
|
let got_domainnames = syscall
|
|
.as_ref()
|
|
.as_any()
|
|
.downcast_ref::<TestHelperSyscall>()
|
|
.unwrap()
|
|
.get_domainname_args();
|
|
assert_eq!(0, got_domainnames.len());
|
|
Ok(())
|
|
}
|
|
|
|
#[test]
|
|
fn test_set_supplementary_gids() -> Result<()> {
|
|
// gids additional gids is empty case
|
|
let user = UserBuilder::default().build().unwrap();
|
|
assert!(set_supplementary_gids(&user, &None, create_syscall().as_ref()).is_ok());
|
|
|
|
let tests = vec![
|
|
(
|
|
UserBuilder::default()
|
|
.additional_gids(vec![33, 34])
|
|
.build()?,
|
|
None::<Rootless>,
|
|
vec![vec![Gid::from_raw(33), Gid::from_raw(34)]],
|
|
),
|
|
// unreachable case
|
|
(
|
|
UserBuilder::default().build()?,
|
|
Some(Rootless::default()),
|
|
vec![],
|
|
),
|
|
(
|
|
UserBuilder::default()
|
|
.additional_gids(vec![37, 38])
|
|
.build()?,
|
|
Some(Rootless {
|
|
privileged: true,
|
|
gid_mappings: None,
|
|
newgidmap: None,
|
|
newuidmap: None,
|
|
uid_mappings: None,
|
|
user_namespace: None,
|
|
..Default::default()
|
|
}),
|
|
vec![vec![Gid::from_raw(37), Gid::from_raw(38)]],
|
|
),
|
|
];
|
|
for (user, rootless, want) in tests.into_iter() {
|
|
let syscall = create_syscall();
|
|
let result = set_supplementary_gids(&user, &rootless, syscall.as_ref());
|
|
match fs::read_to_string("/proc/self/setgroups")?.trim() {
|
|
"deny" => {
|
|
assert!(result.is_err());
|
|
}
|
|
"allow" => {
|
|
assert!(result.is_ok());
|
|
let got = syscall
|
|
.as_any()
|
|
.downcast_ref::<TestHelperSyscall>()
|
|
.unwrap()
|
|
.get_groups_args();
|
|
assert_eq!(want, got);
|
|
}
|
|
_ => unreachable!("setgroups value unknown"),
|
|
}
|
|
}
|
|
Ok(())
|
|
}
|
|
|
|
#[test]
|
|
#[serial]
|
|
#[cfg(feature = "libseccomp")]
|
|
fn test_sync_seccomp() -> Result<()> {
|
|
use std::os::unix::io::IntoRawFd;
|
|
use std::thread;
|
|
|
|
let tmp_file = tempfile::tempfile()?;
|
|
|
|
let (mut main_sender, mut main_receiver) = channel::main_channel()?;
|
|
let (mut init_sender, mut init_receiver) = channel::init_channel()?;
|
|
|
|
let fd = tmp_file.into_raw_fd();
|
|
let th = thread::spawn(move || {
|
|
assert!(main_receiver.wait_for_seccomp_request().is_ok());
|
|
assert!(init_sender.seccomp_notify_done().is_ok());
|
|
});
|
|
|
|
// sync_seccomp close the fd,
|
|
sync_seccomp(Some(fd), &mut main_sender, &mut init_receiver)?;
|
|
// so expecting close the same fd again will causing EBADF error.
|
|
assert_eq!(nix::errno::Errno::EBADF, unistd::close(fd).unwrap_err());
|
|
assert!(th.join().is_ok());
|
|
Ok(())
|
|
}
|
|
|
|
#[test]
|
|
fn test_masked_path_does_not_exist() {
|
|
let syscall = create_syscall();
|
|
let mocks = syscall
|
|
.as_any()
|
|
.downcast_ref::<TestHelperSyscall>()
|
|
.unwrap();
|
|
mocks.set_ret_err(ArgName::Mount, || {
|
|
Err(SyscallError::Nix(nix::errno::Errno::ENOENT))
|
|
});
|
|
|
|
assert!(masked_path(Path::new("/proc/self"), &None, syscall.as_ref()).is_ok());
|
|
let got = mocks.get_mount_args();
|
|
assert_eq!(0, got.len());
|
|
}
|
|
|
|
#[test]
|
|
fn test_masked_path_is_file_with_no_label() {
|
|
let syscall = create_syscall();
|
|
let mocks = syscall
|
|
.as_any()
|
|
.downcast_ref::<TestHelperSyscall>()
|
|
.unwrap();
|
|
mocks.set_ret_err(ArgName::Mount, || {
|
|
Err(SyscallError::Nix(nix::errno::Errno::ENOTDIR))
|
|
});
|
|
|
|
assert!(masked_path(Path::new("/proc/self"), &None, syscall.as_ref()).is_ok());
|
|
|
|
let got = mocks.get_mount_args();
|
|
let want = MountArgs {
|
|
source: Some(PathBuf::from("tmpfs")),
|
|
target: PathBuf::from("/proc/self"),
|
|
fstype: Some("tmpfs".to_string()),
|
|
flags: MsFlags::MS_RDONLY,
|
|
data: Some("".to_string()),
|
|
};
|
|
assert_eq!(1, got.len());
|
|
assert_eq!(want, got[0]);
|
|
}
|
|
|
|
#[test]
|
|
fn test_masked_path_is_file_with_label() {
|
|
let syscall = create_syscall();
|
|
let mocks = syscall
|
|
.as_any()
|
|
.downcast_ref::<TestHelperSyscall>()
|
|
.unwrap();
|
|
mocks.set_ret_err(ArgName::Mount, || {
|
|
Err(SyscallError::Nix(nix::errno::Errno::ENOTDIR))
|
|
});
|
|
|
|
assert!(masked_path(
|
|
Path::new("/proc/self"),
|
|
&Some("default".to_string()),
|
|
syscall.as_ref()
|
|
)
|
|
.is_ok());
|
|
|
|
let got = mocks.get_mount_args();
|
|
let want = MountArgs {
|
|
source: Some(PathBuf::from("tmpfs")),
|
|
target: PathBuf::from("/proc/self"),
|
|
fstype: Some("tmpfs".to_string()),
|
|
flags: MsFlags::MS_RDONLY,
|
|
data: Some("context=\"default\"".to_string()),
|
|
};
|
|
assert_eq!(1, got.len());
|
|
assert_eq!(want, got[0]);
|
|
}
|
|
|
|
#[test]
|
|
fn test_masked_path_with_unknown_error() {
|
|
let syscall = create_syscall();
|
|
let mocks = syscall
|
|
.as_any()
|
|
.downcast_ref::<TestHelperSyscall>()
|
|
.unwrap();
|
|
mocks.set_ret_err(ArgName::Mount, || {
|
|
Err(SyscallError::Nix(nix::errno::Errno::UnknownErrno))
|
|
});
|
|
|
|
assert!(masked_path(Path::new("/proc/self"), &None, syscall.as_ref()).is_err());
|
|
let got = mocks.get_mount_args();
|
|
assert_eq!(0, got.len());
|
|
}
|
|
|
|
#[test]
|
|
fn test_get_executable_path() {
|
|
let non_existing_abs_path = "/some/non/existent/absolute/path";
|
|
let existing_abs_path = "/usr/bin/sh";
|
|
let existing_binary = "sh";
|
|
let non_existing_binary = "non-existent";
|
|
let path_value = "/usr/bin:/bin";
|
|
|
|
assert_eq!(
|
|
get_executable_path(existing_abs_path, path_value),
|
|
Some(PathBuf::from(existing_abs_path))
|
|
);
|
|
assert_eq!(get_executable_path(non_existing_abs_path, path_value), None);
|
|
|
|
assert_eq!(
|
|
get_executable_path(existing_binary, path_value),
|
|
Some(PathBuf::from("/usr/bin/sh"))
|
|
);
|
|
|
|
assert_eq!(get_executable_path(non_existing_binary, path_value), None);
|
|
}
|
|
|
|
#[test]
|
|
fn test_is_executable() {
|
|
let tmp = tempfile::tempdir().expect("create temp directory for test");
|
|
let executable_path = PathBuf::from("/bin/sh");
|
|
let directory_path = tmp.path();
|
|
let non_executable_path = directory_path.join("non_executable_file");
|
|
let non_existent_path = PathBuf::from("/some/non/existent/path");
|
|
|
|
std::fs::File::create(non_executable_path.as_path()).unwrap();
|
|
|
|
assert!(is_executable(&non_existent_path).is_err());
|
|
assert!(is_executable(&executable_path).unwrap());
|
|
assert!(!is_executable(&non_executable_path).unwrap());
|
|
assert!(!is_executable(directory_path).unwrap());
|
|
}
|
|
}
|