diff options
Diffstat (limited to 'pkg/sentry/fs/mounts.go')
-rw-r--r-- | pkg/sentry/fs/mounts.go | 102 |
1 files changed, 15 insertions, 87 deletions
diff --git a/pkg/sentry/fs/mounts.go b/pkg/sentry/fs/mounts.go index b414ddaee..d741c4339 100644 --- a/pkg/sentry/fs/mounts.go +++ b/pkg/sentry/fs/mounts.go @@ -17,13 +17,9 @@ package fs import ( "fmt" "math" - "path" - "strings" "syscall" - "gvisor.dev/gvisor/pkg/abi/linux" "gvisor.dev/gvisor/pkg/context" - "gvisor.dev/gvisor/pkg/log" "gvisor.dev/gvisor/pkg/refs" "gvisor.dev/gvisor/pkg/sentry/kernel/auth" "gvisor.dev/gvisor/pkg/sync" @@ -238,7 +234,7 @@ func (mns *MountNamespace) flushMountSourceRefsLocked() { // After destroy is called, the MountNamespace may continue to be referenced (for // example via /proc/mounts), but should free all resources and shouldn't have // Find* methods called. -func (mns *MountNamespace) destroy() { +func (mns *MountNamespace) destroy(ctx context.Context) { mns.mu.Lock() defer mns.mu.Unlock() @@ -251,13 +247,13 @@ func (mns *MountNamespace) destroy() { for _, mp := range mns.mounts { // Drop the mount reference on all mounted dirents. for ; mp != nil; mp = mp.previous { - mp.root.DecRef() + mp.root.DecRef(ctx) } } mns.mounts = nil // Drop reference on the root. - mns.root.DecRef() + mns.root.DecRef(ctx) // Ensure that root cannot be accessed via this MountNamespace any // more. @@ -269,8 +265,8 @@ func (mns *MountNamespace) destroy() { } // DecRef implements RefCounter.DecRef with destructor mns.destroy. -func (mns *MountNamespace) DecRef() { - mns.DecRefWithDestructor(mns.destroy) +func (mns *MountNamespace) DecRef(ctx context.Context) { + mns.DecRefWithDestructor(ctx, mns.destroy) } // withMountLocked prevents further walks to `node`, because `node` is about to @@ -316,7 +312,7 @@ func (mns *MountNamespace) Mount(ctx context.Context, mountPoint *Dirent, inode if err != nil { return err } - defer replacement.DecRef() + defer replacement.DecRef(ctx) // Set the mount's root dirent and id. parentMnt := mns.findMountLocked(mountPoint) @@ -398,7 +394,7 @@ func (mns *MountNamespace) Unmount(ctx context.Context, node *Dirent, detachOnly panic(fmt.Sprintf("Last mount in the chain must be a undo mount: %+v", prev)) } // Drop mount reference taken at the end of MountNamespace.Mount. - prev.root.DecRef() + prev.root.DecRef(ctx) } else { mns.mounts[prev.root] = prev } @@ -500,11 +496,11 @@ func (mns *MountNamespace) FindLink(ctx context.Context, root, wd *Dirent, path // non-directory root is hopeless. if current != root { if !IsDir(current.Inode.StableAttr) { - current.DecRef() // Drop reference from above. + current.DecRef(ctx) // Drop reference from above. return nil, syserror.ENOTDIR } if err := current.Inode.CheckPermission(ctx, PermMask{Execute: true}); err != nil { - current.DecRef() // Drop reference from above. + current.DecRef(ctx) // Drop reference from above. return nil, err } } @@ -515,12 +511,12 @@ func (mns *MountNamespace) FindLink(ctx context.Context, root, wd *Dirent, path // Allow failed walks to cache the dirent, because no // children will acquire a reference at the end. current.maybeExtendReference() - current.DecRef() + current.DecRef(ctx) return nil, err } // Drop old reference. - current.DecRef() + current.DecRef(ctx) if remainder != "" { // Ensure it's resolved, unless it's the last level. @@ -574,11 +570,11 @@ func (mns *MountNamespace) resolve(ctx context.Context, root, node *Dirent, rema case nil: // Make sure we didn't exhaust the traversal budget. if *remainingTraversals == 0 { - target.DecRef() + target.DecRef(ctx) return nil, syscall.ELOOP } - node.DecRef() // Drop the original reference. + node.DecRef(ctx) // Drop the original reference. return target, nil case syscall.ENOLINK: @@ -586,7 +582,7 @@ func (mns *MountNamespace) resolve(ctx context.Context, root, node *Dirent, rema return node, nil case ErrResolveViaReadlink: - defer node.DecRef() // See above. + defer node.DecRef(ctx) // See above. // First, check if we should traverse. if *remainingTraversals == 0 { @@ -612,7 +608,7 @@ func (mns *MountNamespace) resolve(ctx context.Context, root, node *Dirent, rema return d, err default: - node.DecRef() // Drop for err; see above. + node.DecRef(ctx) // Drop for err; see above. // Propagate the error. return nil, err @@ -625,71 +621,3 @@ func (mns *MountNamespace) SyncAll(ctx context.Context) { defer mns.mu.Unlock() mns.root.SyncAll(ctx) } - -// ResolveExecutablePath resolves the given executable name given a set of -// paths that might contain it. -func (mns *MountNamespace) ResolveExecutablePath(ctx context.Context, wd, name string, paths []string) (string, error) { - // Absolute paths can be used directly. - if path.IsAbs(name) { - return name, nil - } - - // Paths with '/' in them should be joined to the working directory, or - // to the root if working directory is not set. - if strings.IndexByte(name, '/') > 0 { - if wd == "" { - wd = "/" - } - if !path.IsAbs(wd) { - return "", fmt.Errorf("working directory %q must be absolute", wd) - } - return path.Join(wd, name), nil - } - - // Otherwise, We must lookup the name in the paths, starting from the - // calling context's root directory. - root := RootFromContext(ctx) - if root == nil { - // Caller has no root. Don't bother traversing anything. - return "", syserror.ENOENT - } - defer root.DecRef() - for _, p := range paths { - binPath := path.Join(p, name) - traversals := uint(linux.MaxSymlinkTraversals) - d, err := mns.FindInode(ctx, root, nil, binPath, &traversals) - if err == syserror.ENOENT || err == syserror.EACCES { - // Didn't find it here. - continue - } - if err != nil { - return "", err - } - defer d.DecRef() - - // Check that it is a regular file. - if !IsRegular(d.Inode.StableAttr) { - continue - } - - // Check whether we can read and execute the found file. - if err := d.Inode.CheckPermission(ctx, PermMask{Read: true, Execute: true}); err != nil { - log.Infof("Found executable at %q, but user cannot execute it: %v", binPath, err) - continue - } - return path.Join("/", p, name), nil - } - return "", syserror.ENOENT -} - -// GetPath returns the PATH as a slice of strings given the environment -// variables. -func GetPath(env []string) []string { - const prefix = "PATH=" - for _, e := range env { - if strings.HasPrefix(e, prefix) { - return strings.Split(strings.TrimPrefix(e, prefix), ":") - } - } - return nil -} |