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author | Stephen Barber <smbarber@chromium.org> | 2018-02-21 14:17:27 -0800 |
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committer | chrome-bot <chrome-bot@chromium.org> | 2018-02-21 22:26:53 -0800 |
commit | c79de2d0b2b75c18adf1b9f1779a6b482247531e (patch) | |
tree | a77ca1e92c813453ebe03f6d26d47be0533d858f /src/linux.rs | |
parent | 859b5d9d147fc59e42d3eeccd9b7bc7f857a2b01 (diff) | |
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crosvm: add advisory locking for disk images
Disk images should never be mounted as writable by multiple VMs at once. Add advisory locking to prevent this. BUG=chromium:810576 TEST=run crosvm twice with same rwdisk, check that second VM fails to start Change-Id: I5e6c178515eafa570812a093449eef5a4edc1740 Reviewed-on: https://chromium-review.googlesource.com/929994 Commit-Ready: Stephen Barber <smbarber@chromium.org> Tested-by: Stephen Barber <smbarber@chromium.org> Reviewed-by: Dylan Reid <dgreid@chromium.org> Reviewed-by: Zach Reizner <zachr@chromium.org>
Diffstat (limited to 'src/linux.rs')
-rw-r--r-- | src/linux.rs | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/src/linux.rs b/src/linux.rs index c0b9094..b4c76d9 100644 --- a/src/linux.rs +++ b/src/linux.rs @@ -53,6 +53,7 @@ pub enum Error { DeviceJail(io_jail::Error), DevicePivotRoot(io_jail::Error), Disk(io::Error), + DiskImageLock(sys_util::Error), GetWaylandGroup(sys_util::Error), LoadCmdline(kernel_loader::Error), LoadKernel(kernel_loader::Error), @@ -107,6 +108,7 @@ impl fmt::Display for Error { &Error::DeviceJail(ref e) => write!(f, "failed to jail device: {}", e), &Error::DevicePivotRoot(ref e) => write!(f, "failed to pivot root device: {}", e), &Error::Disk(ref e) => write!(f, "failed to load disk image: {}", e), + &Error::DiskImageLock(ref e) => write!(f, "failed to lock disk image: {:?}", e), &Error::GetWaylandGroup(ref e) => { write!(f, "could not find gid for wayland group: {:?}", e) } @@ -303,6 +305,14 @@ fn setup_mmio_bus(cfg: &Config, .write(disk.writable) .open(&disk.path) .map_err(|e| Error::Disk(e))?; + // Lock the disk image to prevent other crosvm instances from using it. + let lock_op = if disk.writable { + FlockOperation::LockExclusive + } else { + FlockOperation::LockShared + }; + flock(&raw_image, lock_op, true).map_err(Error::DiskImageLock)?; + let block_box: Box<devices::virtio::VirtioDevice> = match disk.disk_type { DiskType::FlatFile => { // Access as a raw block device. Box::new(devices::virtio::Block::new(raw_image) |