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Diffstat (limited to 'pkg/sentry/kernel/kernel.go')
-rw-r--r--pkg/sentry/kernel/kernel.go145
1 files changed, 114 insertions, 31 deletions
diff --git a/pkg/sentry/kernel/kernel.go b/pkg/sentry/kernel/kernel.go
index 3ee760ba2..2665f057c 100644
--- a/pkg/sentry/kernel/kernel.go
+++ b/pkg/sentry/kernel/kernel.go
@@ -43,11 +43,13 @@ import (
"gvisor.dev/gvisor/pkg/context"
"gvisor.dev/gvisor/pkg/cpuid"
"gvisor.dev/gvisor/pkg/eventchannel"
+ "gvisor.dev/gvisor/pkg/fspath"
"gvisor.dev/gvisor/pkg/log"
"gvisor.dev/gvisor/pkg/refs"
"gvisor.dev/gvisor/pkg/sentry/arch"
"gvisor.dev/gvisor/pkg/sentry/fs"
"gvisor.dev/gvisor/pkg/sentry/fs/timerfd"
+ "gvisor.dev/gvisor/pkg/sentry/fsbridge"
"gvisor.dev/gvisor/pkg/sentry/hostcpu"
"gvisor.dev/gvisor/pkg/sentry/inet"
"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
@@ -71,6 +73,10 @@ import (
"gvisor.dev/gvisor/pkg/tcpip"
)
+// VFS2Enabled is set to true when VFS2 is enabled. Added as a global for allow
+// easy access everywhere. To be removed once VFS2 becomes the default.
+var VFS2Enabled = false
+
// Kernel represents an emulated Linux kernel. It must be initialized by calling
// Init() or LoadFrom().
//
@@ -238,6 +244,9 @@ type Kernel struct {
// SpecialOpts contains special kernel options.
SpecialOpts
+
+ // VFS keeps the filesystem state used across the kernel.
+ VFS *vfs.VirtualFilesystem
}
// InitKernelArgs holds arguments to Init.
@@ -624,7 +633,7 @@ type CreateProcessArgs struct {
// File is a passed host FD pointing to a file to load as the init binary.
//
// This is checked if and only if Filename is "".
- File *fs.File
+ File fsbridge.File
// Argvv is a list of arguments.
Argv []string
@@ -673,6 +682,13 @@ type CreateProcessArgs struct {
// increment it).
MountNamespace *fs.MountNamespace
+ // MountNamespaceVFS2 optionally contains the mount namespace for this
+ // process. If nil, the init process's mount namespace is used.
+ //
+ // Anyone setting MountNamespaceVFS2 must donate a reference (i.e.
+ // increment it).
+ MountNamespaceVFS2 *vfs.MountNamespace
+
// ContainerID is the container that the process belongs to.
ContainerID string
}
@@ -711,11 +727,22 @@ func (ctx *createProcessContext) Value(key interface{}) interface{} {
return ctx.args.Credentials
case fs.CtxRoot:
if ctx.args.MountNamespace != nil {
- // MountNamespace.Root() will take a reference on the root
- // dirent for us.
+ // MountNamespace.Root() will take a reference on the root dirent for us.
return ctx.args.MountNamespace.Root()
}
return nil
+ case vfs.CtxRoot:
+ if ctx.args.MountNamespaceVFS2 == nil {
+ return nil
+ }
+ // MountNamespaceVFS2.Root() takes a reference on the root dirent for us.
+ return ctx.args.MountNamespaceVFS2.Root()
+ case vfs.CtxMountNamespace:
+ if ctx.k.globalInit == nil {
+ return nil
+ }
+ // MountNamespaceVFS2 takes a reference for us.
+ return ctx.k.GlobalInit().Leader().MountNamespaceVFS2()
case fs.CtxDirentCacheLimiter:
return ctx.k.DirentCacheLimiter
case ktime.CtxRealtimeClock:
@@ -757,34 +784,77 @@ func (k *Kernel) CreateProcess(args CreateProcessArgs) (*ThreadGroup, ThreadID,
defer k.extMu.Unlock()
log.Infof("EXEC: %v", args.Argv)
- // Grab the mount namespace.
- mounts := args.MountNamespace
- if mounts == nil {
- mounts = k.GlobalInit().Leader().MountNamespace()
- mounts.IncRef()
- }
-
- tg := k.NewThreadGroup(mounts, args.PIDNamespace, NewSignalHandlers(), linux.SIGCHLD, args.Limits)
ctx := args.NewContext(k)
- // Get the root directory from the MountNamespace.
- root := mounts.Root()
- // The call to newFSContext below will take a reference on root, so we
- // don't need to hold this one.
- defer root.DecRef()
-
- // Grab the working directory.
- remainingTraversals := uint(args.MaxSymlinkTraversals)
- wd := root // Default.
- if args.WorkingDirectory != "" {
- var err error
- wd, err = mounts.FindInode(ctx, root, nil, args.WorkingDirectory, &remainingTraversals)
- if err != nil {
- return nil, 0, fmt.Errorf("failed to find initial working directory %q: %v", args.WorkingDirectory, err)
+ var (
+ opener fsbridge.Lookup
+ fsContext *FSContext
+ mntns *fs.MountNamespace
+ )
+
+ if VFS2Enabled {
+ mntnsVFS2 := args.MountNamespaceVFS2
+ if mntnsVFS2 == nil {
+ // MountNamespaceVFS2 adds a reference to the namespace, which is
+ // transferred to the new process.
+ mntnsVFS2 = k.GlobalInit().Leader().MountNamespaceVFS2()
+ }
+ // Get the root directory from the MountNamespace.
+ root := args.MountNamespaceVFS2.Root()
+ // The call to newFSContext below will take a reference on root, so we
+ // don't need to hold this one.
+ defer root.DecRef()
+
+ // Grab the working directory.
+ wd := root // Default.
+ if args.WorkingDirectory != "" {
+ pop := vfs.PathOperation{
+ Root: root,
+ Start: wd,
+ Path: fspath.Parse(args.WorkingDirectory),
+ FollowFinalSymlink: true,
+ }
+ var err error
+ wd, err = k.VFS.GetDentryAt(ctx, args.Credentials, &pop, &vfs.GetDentryOptions{
+ CheckSearchable: true,
+ })
+ if err != nil {
+ return nil, 0, fmt.Errorf("failed to find initial working directory %q: %v", args.WorkingDirectory, err)
+ }
+ defer wd.DecRef()
+ }
+ opener = fsbridge.NewVFSLookup(mntnsVFS2, root, wd)
+ fsContext = NewFSContextVFS2(root, wd, args.Umask)
+
+ } else {
+ mntns = args.MountNamespace
+ if mntns == nil {
+ mntns = k.GlobalInit().Leader().MountNamespace()
+ mntns.IncRef()
}
- defer wd.DecRef()
+ // Get the root directory from the MountNamespace.
+ root := mntns.Root()
+ // The call to newFSContext below will take a reference on root, so we
+ // don't need to hold this one.
+ defer root.DecRef()
+
+ // Grab the working directory.
+ remainingTraversals := args.MaxSymlinkTraversals
+ wd := root // Default.
+ if args.WorkingDirectory != "" {
+ var err error
+ wd, err = mntns.FindInode(ctx, root, nil, args.WorkingDirectory, &remainingTraversals)
+ if err != nil {
+ return nil, 0, fmt.Errorf("failed to find initial working directory %q: %v", args.WorkingDirectory, err)
+ }
+ defer wd.DecRef()
+ }
+ opener = fsbridge.NewFSLookup(mntns, root, wd)
+ fsContext = newFSContext(root, wd, args.Umask)
}
+ tg := k.NewThreadGroup(mntns, args.PIDNamespace, NewSignalHandlers(), linux.SIGCHLD, args.Limits)
+
// Check which file to start from.
switch {
case args.Filename != "":
@@ -805,11 +875,9 @@ func (k *Kernel) CreateProcess(args CreateProcessArgs) (*ThreadGroup, ThreadID,
}
// Create a fresh task context.
- remainingTraversals = uint(args.MaxSymlinkTraversals)
+ remainingTraversals := args.MaxSymlinkTraversals
loadArgs := loader.LoadArgs{
- Mounts: mounts,
- Root: root,
- WorkingDirectory: wd,
+ Opener: opener,
RemainingTraversals: &remainingTraversals,
ResolveFinal: true,
Filename: args.Filename,
@@ -834,13 +902,14 @@ func (k *Kernel) CreateProcess(args CreateProcessArgs) (*ThreadGroup, ThreadID,
Kernel: k,
ThreadGroup: tg,
TaskContext: tc,
- FSContext: newFSContext(root, wd, args.Umask),
+ FSContext: fsContext,
FDTable: args.FDTable,
Credentials: args.Credentials,
AllowedCPUMask: sched.NewFullCPUSet(k.applicationCores),
UTSNamespace: args.UTSNamespace,
IPCNamespace: args.IPCNamespace,
AbstractSocketNamespace: args.AbstractSocketNamespace,
+ MountNamespaceVFS2: args.MountNamespaceVFS2,
ContainerID: args.ContainerID,
}
t, err := k.tasks.NewTask(config)
@@ -1378,6 +1447,20 @@ func (ctx supervisorContext) Value(key interface{}) interface{} {
return ctx.k.globalInit.mounts.Root()
}
return nil
+ case vfs.CtxRoot:
+ if ctx.k.globalInit == nil {
+ return vfs.VirtualDentry{}
+ }
+ mntns := ctx.k.GlobalInit().Leader().MountNamespaceVFS2()
+ defer mntns.DecRef()
+ // Root() takes a reference on the root dirent for us.
+ return mntns.Root()
+ case vfs.CtxMountNamespace:
+ if ctx.k.globalInit == nil {
+ return nil
+ }
+ // MountNamespaceVFS2() takes a reference for us.
+ return ctx.k.GlobalInit().Leader().MountNamespaceVFS2()
case fs.CtxDirentCacheLimiter:
return ctx.k.DirentCacheLimiter
case ktime.CtxRealtimeClock:
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-01 17:37:49 +0000