[lxc-devel] [lxd/master] Replaces ExtractSnapshotName with ContainerGetParentAndSnapshotName

tomponline on Github lxc-bot at linuxcontainers.org
Thu Oct 17 09:54:04 UTC 2019


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From 9b3a8998daa65d79d5aa261dfa3983856d48112b Mon Sep 17 00:00:00 2001
From: Thomas Parrott <thomas.parrott at canonical.com>
Date: Thu, 17 Oct 2019 10:30:34 +0100
Subject: [PATCH 1/3] lxc/storage/volume: Fix panic when invalid snapshot
 rename argument supplied

When running

 lxc storage volume rename test myvol6/snap0 myvol18

I got this crash:

panic: runtime error: index out of range

goroutine 1 [running]:
github.com/lxc/lxd/shared.ExtractSnapshotName(0x7fff387181b1, 0x7, 0xb512d6, 0x1)
	/home/user/go/src/github.com/lxc/lxd/shared/util.go:487 +0x84
main.(*cmdStorageVolumeRename).Run(0xc42022ad60, 0xc4202a4f00, 0xc420288ae0, 0x3, 0x3, 0x0, 0x0)
	/home/user/go/src/github.com/lxc/lxd/lxc/storage_volume.go:1217 +0x285
main.(*cmdStorageVolumeRename).Run-fm(0xc4202a4f00, 0xc420288ae0, 0x3, 0x3, 0x0, 0x0)
	/home/user/go/src/github.com/lxc/lxd/lxc/storage_volume.go:1177 +0x52
github.com/spf13/cobra.(*Command).execute(0xc4202a4f00, 0xc420288a20, 0x3, 0x3, 0xc4202a4f00, 0xc420288a20)
	/home/user/go/src/github.com/spf13/cobra/command.go:829 +0x468
github.com/spf13/cobra.(*Command).ExecuteC(0xc420208280, 0x0, 0xc420296d80, 0x19)
	/home/user/go/src/github.com/spf13/cobra/command.go:917 +0x306
github.com/spf13/cobra.(*Command).Execute(0xc420208280, 0xc4200aa010, 0x6)
	/home/user/go/src/github.com/spf13/cobra/command.go:867 +0x2b
main.main()
	/home/user/go/src/github.com/lxc/lxd/lxc/main.go:238 +0x1de8

This is because the rename command is expecting the 2nd volume name in the format:

 lxc storage volume rename test myvol6/snap0 myvol6/newname

This fixes this issue, as using ExtractSnapshotName is unsafe if you've not checked whether the volume name is a snapshot or not.

Signed-off-by: Thomas Parrott <thomas.parrott at canonical.com>
---
 lxc/storage_volume.go | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/lxc/storage_volume.go b/lxc/storage_volume.go
index 111ae58df2..9bdc70de5e 100644
--- a/lxc/storage_volume.go
+++ b/lxc/storage_volume.go
@@ -1214,7 +1214,13 @@ func (c *cmdStorageVolumeRename) Run(cmd *cobra.Command, args []string) error {
 	if isSnapshot {
 		// Create the storage volume entry
 		vol := api.StorageVolumeSnapshotPost{}
-		vol.Name = shared.ExtractSnapshotName(args[2])
+		_, dstSnapName, dstIsSnap := shared.ContainerGetParentAndSnapshotName(args[2])
+
+		if !dstIsSnap {
+			return fmt.Errorf("Invalid new snapshot name")
+		}
+
+		vol.Name = dstSnapName
 
 		// If a target member was specified, get the volume with the matching
 		// name on that member, if any.

From c5e766b0a35dbd34ce513c34b0f8c0a85374754b Mon Sep 17 00:00:00 2001
From: Thomas Parrott <thomas.parrott at canonical.com>
Date: Thu, 17 Oct 2019 10:32:42 +0100
Subject: [PATCH 2/3] shared/util: Removes ExtractSnapshotName

ExtractSnapshotName was dangerous to use as it did not validate the lenth of the slice returned when splitting the supplied volume name by the snapshot delimiter (/).

When used with untrusted inputs it could cause a crash.

Additionally it's functionality overlapped with the safer and more feature rich ContainerGetParentAndSnapshotName, so have removed in place of that.

Signed-off-by: Thomas Parrott <thomas.parrott at canonical.com>
---
 shared/util.go | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/shared/util.go b/shared/util.go
index 4bcfc30bbc..e307f985fe 100644
--- a/shared/util.go
+++ b/shared/util.go
@@ -483,10 +483,6 @@ func IsSnapshot(name string) bool {
 	return strings.Contains(name, SnapshotDelimiter)
 }
 
-func ExtractSnapshotName(name string) string {
-	return strings.SplitN(name, SnapshotDelimiter, 2)[1]
-}
-
 func MkdirAllOwner(path string, perm os.FileMode, uid int, gid int) error {
 	// This function is a slightly modified version of MkdirAll from the Go standard library.
 	// https://golang.org/src/os/path.go?s=488:535#L9

From ff178f7a248900ca41da6e7752e11a439c1debaf Mon Sep 17 00:00:00 2001
From: Thomas Parrott <thomas.parrott at canonical.com>
Date: Thu, 17 Oct 2019 10:36:18 +0100
Subject: [PATCH 3/3] lxd: Changes use of ExtractSnapshotName to
 ContainerGetParentAndSnapshotName

Signed-off-by: Thomas Parrott <thomas.parrott at canonical.com>
---
 lxd/migrate_container.go       | 3 ++-
 lxd/migrate_storage_volumes.go | 5 +++--
 lxd/storage_volumes_utils.go   | 3 ++-
 3 files changed, 7 insertions(+), 4 deletions(-)

diff --git a/lxd/migrate_container.go b/lxd/migrate_container.go
index 1a0c094556..69b5d362ff 100644
--- a/lxd/migrate_container.go
+++ b/lxd/migrate_container.go
@@ -386,7 +386,8 @@ func (s *migrationSourceWs) Do(migrateOp *operations.Operation) error {
 		if err == nil {
 			for _, snap := range fullSnaps {
 				snapshots = append(snapshots, snapshotToProtobuf(snap))
-				snapshotNames = append(snapshotNames, shared.ExtractSnapshotName(snap.Name()))
+				_, snapName, _ := shared.ContainerGetParentAndSnapshotName(snap.Name())
+				snapshotNames = append(snapshotNames, snapName)
 			}
 		}
 	}
diff --git a/lxd/migrate_storage_volumes.go b/lxd/migrate_storage_volumes.go
index 05ba8e7186..1c492dedb2 100644
--- a/lxd/migrate_storage_volumes.go
+++ b/lxd/migrate_storage_volumes.go
@@ -69,7 +69,8 @@ func (s *migrationSourceWs) DoStorage(migrateOp *operations.Operation) error {
 					}
 
 					snapshots = append(snapshots, volumeSnapshotToProtobuf(snapVolume))
-					snapshotNames = append(snapshotNames, shared.ExtractSnapshotName(name))
+					_, snapName, _ := shared.ContainerGetParentAndSnapshotName(name)
+					snapshotNames = append(snapshotNames, snapName)
 				}
 			}
 
@@ -429,7 +430,7 @@ func volumeSnapshotToProtobuf(vol *api.StorageVolume) *migration.Snapshot {
 		config = append(config, &migration.Config{Key: &kCopy, Value: &vCopy})
 	}
 
-	snapOnlyName := shared.ExtractSnapshotName(vol.Name)
+	_, snapOnlyName, _ := shared.ContainerGetParentAndSnapshotName(vol.Name)
 
 	return &migration.Snapshot{
 		Name:         &snapOnlyName,
diff --git a/lxd/storage_volumes_utils.go b/lxd/storage_volumes_utils.go
index 46eeb2fac8..aa02763399 100644
--- a/lxd/storage_volumes_utils.go
+++ b/lxd/storage_volumes_utils.go
@@ -647,7 +647,8 @@ func storagePoolVolumeCreateInternal(state *state.State, poolName string, vol *a
 			}
 
 			for _, snap := range snapshots {
-				_, err := storagePoolVolumeSnapshotCopyInternal(state, poolName, vol, shared.ExtractSnapshotName(snap))
+				_, snapName, _ := shared.ContainerGetParentAndSnapshotName(snap)
+				_, err := storagePoolVolumeSnapshotCopyInternal(state, poolName, vol, snapName)
 				if err != nil {
 					return err
 				}


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