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rustjail: implement functions to mount and umount files

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Use conditional compilation (#[cfg]) to change mount and umount
behaviours at compilation time. For example, such functions will just
return `Ok(())` when the unit tests are being compiled, otherwise real
mount and umount operations are performed.

Signed-off-by: Julio Montes <julio.montes@intel.com>
This commit is contained in:
Julio Montes 2020-08-25 15:54:34 -05:00
parent 53b0e085e1
commit d756f52c73
1 changed files with 45 additions and 20 deletions
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65
src/agent/rustjail/src/mount.rs
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@ -102,6 +102,31 @@ lazy_static! {
}; };
} }
#[inline(always)]
fn mount<P1: ?Sized + NixPath, P2: ?Sized + NixPath, P3: ?Sized + NixPath, P4: ?Sized + NixPath>(
source: Option<&P1>,
target: &P2,
fstype: Option<&P3>,
flags: MsFlags,
data: Option<&P4>,
) -> std::result::Result<(), nix::Error> {
#[cfg(not(test))]
return mount::mount(source, target, fstype, flags, data);
#[cfg(test)]
return Ok(());
}
#[inline(always)]
fn umount2<P: ?Sized + NixPath>(
target: &P,
flags: MntFlags,
) -> std::result::Result<(), nix::Error> {
#[cfg(not(test))]
return mount::umount2(target, flags);
#[cfg(test)]
return Ok(());
}
pub fn init_rootfs( pub fn init_rootfs(
cfd_log: RawFd, cfd_log: RawFd,
spec: &Spec, spec: &Spec,
@ -124,11 +149,11 @@ pub fn init_rootfs(
let root = fs::canonicalize(rootfs)?; let root = fs::canonicalize(rootfs)?;
let rootfs = root.to_str().unwrap(); let rootfs = root.to_str().unwrap();
mount::mount(None::<&str>, "/", None::<&str>, flags, None::<&str>)?; mount(None::<&str>, "/", None::<&str>, flags, None::<&str>)?;
rootfs_parent_mount_private(rootfs)?; rootfs_parent_mount_private(rootfs)?;
mount::mount( mount(
Some(rootfs), Some(rootfs),
rootfs, rootfs,
None::<&str>, None::<&str>,
@ -157,7 +182,7 @@ pub fn init_rootfs(
for o in &m.options { for o in &m.options {
if let Some(fl) = PROPAGATION.get(o.as_str()) { if let Some(fl) = PROPAGATION.get(o.as_str()) {
let dest = format!("{}{}", &rootfs, &m.destination); let dest = format!("{}{}", &rootfs, &m.destination);
mount::mount(None::<&str>, dest.as_str(), None::<&str>, *fl, None::<&str>)?; mount(None::<&str>, dest.as_str(), None::<&str>, *fl, None::<&str>)?;
} }
} }
} }
@ -196,7 +221,7 @@ fn mount_cgroups_v2(cfd_log: RawFd, m: &Mount, rootfs: &str, flags: MsFlags) ->
if flags.contains(MsFlags::MS_RDONLY) { if flags.contains(MsFlags::MS_RDONLY) {
let dest = format!("{}{}", rootfs, m.destination.as_str()); let dest = format!("{}{}", rootfs, m.destination.as_str());
mount::mount( mount(
Some(dest.as_str()), Some(dest.as_str()),
dest.as_str(), dest.as_str(),
None::<&str>, None::<&str>,
@ -303,7 +328,7 @@ fn mount_cgroups(
if flags.contains(MsFlags::MS_RDONLY) { if flags.contains(MsFlags::MS_RDONLY) {
let dest = format!("{}{}", rootfs, m.destination.as_str()); let dest = format!("{}{}", rootfs, m.destination.as_str());
mount::mount( mount(
Some(dest.as_str()), Some(dest.as_str()),
dest.as_str(), dest.as_str(),
None::<&str>, None::<&str>,
@ -336,7 +361,7 @@ pub fn pivot_rootfs<P: ?Sized + NixPath + std::fmt::Debug>(path: &P) -> Result<(
// to races where we still have a reference to a mount while a process in // to races where we still have a reference to a mount while a process in
// the host namespace are trying to operate on something they think has no // the host namespace are trying to operate on something they think has no
// mounts (devicemapper in particular). // mounts (devicemapper in particular).
mount::mount( mount(
Some("none"), Some("none"),
".", ".",
Some(""), Some(""),
@ -345,7 +370,7 @@ pub fn pivot_rootfs<P: ?Sized + NixPath + std::fmt::Debug>(path: &P) -> Result<(
)?; )?;
// Preform the unmount. MNT_DETACH allows us to unmount /proc/self/cwd. // Preform the unmount. MNT_DETACH allows us to unmount /proc/self/cwd.
mount::umount2(".", MntFlags::MNT_DETACH).context("failed to do umount2")?; umount2(".", MntFlags::MNT_DETACH).context("failed to do umount2")?;
// Switch back to our shiny new root. // Switch back to our shiny new root.
unistd::chdir("/")?; unistd::chdir("/")?;
@ -368,7 +393,7 @@ fn rootfs_parent_mount_private(path: &str) -> Result<()> {
} }
if options.contains("shared:") { if options.contains("shared:") {
mount::mount( mount(
None::<&str>, None::<&str>,
mount_point.as_str(), mount_point.as_str(),
None::<&str>, None::<&str>,
@ -463,14 +488,14 @@ pub fn ms_move_root(rootfs: &str) -> Result<bool> {
} }
// Be sure umount events are not propagated to the host. // Be sure umount events are not propagated to the host.
mount::mount( mount(
None::<&str>, None::<&str>,
abs_mount_point, abs_mount_point,
None::<&str>, None::<&str>,
MsFlags::MS_SLAVE | MsFlags::MS_REC, MsFlags::MS_SLAVE | MsFlags::MS_REC,
None::<&str>, None::<&str>,
)?; )?;
match mount::umount2(abs_mount_point, MntFlags::MNT_DETACH) { match umount2(abs_mount_point, MntFlags::MNT_DETACH) {
Ok(_) => (), Ok(_) => (),
Err(e) => { Err(e) => {
if e.ne(&nix::Error::from(Errno::EINVAL)) && e.ne(&nix::Error::from(Errno::EPERM)) { if e.ne(&nix::Error::from(Errno::EINVAL)) && e.ne(&nix::Error::from(Errno::EPERM)) {
@ -479,7 +504,7 @@ pub fn ms_move_root(rootfs: &str) -> Result<bool> {
// If we have not privileges for umounting (e.g. rootless), then // If we have not privileges for umounting (e.g. rootless), then
// cover the path. // cover the path.
mount::mount( mount(
Some("tmpfs"), Some("tmpfs"),
abs_mount_point, abs_mount_point,
Some("tmpfs"), Some("tmpfs"),
@ -490,7 +515,7 @@ pub fn ms_move_root(rootfs: &str) -> Result<bool> {
} }
} }
mount::mount( mount(
Some(abs_root), Some(abs_root),
"/", "/",
None::<&str>, None::<&str>,
@ -584,7 +609,7 @@ fn mount_from(
} }
} }
match mount::mount( match mount(
Some(src.as_str()), Some(src.as_str()),
dest.as_str(), dest.as_str(),
Some(m.r#type.as_str()), Some(m.r#type.as_str()),
@ -608,7 +633,7 @@ fn mount_from(
| MsFlags::MS_SLAVE), | MsFlags::MS_SLAVE),
) )
{ {
match mount::mount( match mount(
Some(dest.as_str()), Some(dest.as_str()),
dest.as_str(), dest.as_str(),
None::<&str>, None::<&str>,
@ -714,7 +739,7 @@ fn bind_dev(dev: &LinuxDevice) -> Result<()> {
unistd::close(fd)?; unistd::close(fd)?;
mount::mount( mount(
Some(&*dev.path), Some(&*dev.path),
&dev.path[1..], &dev.path[1..],
None::<&str>, None::<&str>,
@ -744,7 +769,7 @@ pub fn finish_rootfs(cfd_log: RawFd, spec: &Spec) -> Result<()> {
if m.destination == "/dev" { if m.destination == "/dev" {
let (flags, _) = parse_mount(m); let (flags, _) = parse_mount(m);
if flags.contains(MsFlags::MS_RDONLY) { if flags.contains(MsFlags::MS_RDONLY) {
mount::mount( mount(
Some("/dev"), Some("/dev"),
"/dev", "/dev",
None::<&str>, None::<&str>,
@ -758,7 +783,7 @@ pub fn finish_rootfs(cfd_log: RawFd, spec: &Spec) -> Result<()> {
if spec.root.as_ref().unwrap().readonly { if spec.root.as_ref().unwrap().readonly {
let flags = MsFlags::MS_BIND | MsFlags::MS_RDONLY | MsFlags::MS_NODEV | MsFlags::MS_REMOUNT; let flags = MsFlags::MS_BIND | MsFlags::MS_RDONLY | MsFlags::MS_NODEV | MsFlags::MS_REMOUNT;
mount::mount(Some("/"), "/", None::<&str>, flags, None::<&str>)?; mount(Some("/"), "/", None::<&str>, flags, None::<&str>)?;
} }
stat::umask(Mode::from_bits_truncate(0o022)); stat::umask(Mode::from_bits_truncate(0o022));
unistd::chdir(&olddir)?; unistd::chdir(&olddir)?;
@ -773,7 +798,7 @@ fn mask_path(path: &str) -> Result<()> {
//info!("{}", path); //info!("{}", path);
match mount::mount( match mount(
Some("/dev/null"), Some("/dev/null"),
path, path,
None::<&str>, None::<&str>,
@ -805,7 +830,7 @@ fn readonly_path(path: &str) -> Result<()> {
//info!("{}", path); //info!("{}", path);
match mount::mount( match mount(
Some(&path[1..]), Some(&path[1..]),
path, path,
None::<&str>, None::<&str>,
@ -829,7 +854,7 @@ fn readonly_path(path: &str) -> Result<()> {
Ok(_) => {} Ok(_) => {}
} }
mount::mount( mount(
Some(&path[1..]), Some(&path[1..]),
&path[1..], &path[1..],
None::<&str>, None::<&str>,