From ce19497c1c0829af6ba56f0cc68e3a4cb33cf1c8 Mon Sep 17 00:00:00 2001 From: Dean Deng Date: Tue, 28 Apr 2020 20:11:43 -0700 Subject: Fix Unix socket permissions. Enforce write permission checks in BoundEndpointAt, which corresponds to the permission checks in Linux (net/unix/af_unix.c:unix_find_other). Also, create bound socket files with the correct permissions in VFS2. Fixes #2324. PiperOrigin-RevId: 308949084 --- pkg/sentry/fsimpl/ext/filesystem.go | 5 ++++- pkg/sentry/fsimpl/kernfs/filesystem.go | 5 ++++- pkg/sentry/fsimpl/tmpfs/filesystem.go | 3 +++ 3 files changed, 11 insertions(+), 2 deletions(-) (limited to 'pkg/sentry/fsimpl') diff --git a/pkg/sentry/fsimpl/ext/filesystem.go b/pkg/sentry/fsimpl/ext/filesystem.go index 6c882d0b6..77b644275 100644 --- a/pkg/sentry/fsimpl/ext/filesystem.go +++ b/pkg/sentry/fsimpl/ext/filesystem.go @@ -486,10 +486,13 @@ func (fs *filesystem) UnlinkAt(ctx context.Context, rp *vfs.ResolvingPath) error // BoundEndpointAt implements FilesystemImpl.BoundEndpointAt. func (fs *filesystem) BoundEndpointAt(ctx context.Context, rp *vfs.ResolvingPath, opts vfs.BoundEndpointOptions) (transport.BoundEndpoint, error) { - _, _, err := fs.walk(rp, false) + _, inode, err := fs.walk(rp, false) if err != nil { return nil, err } + if err := inode.checkPermissions(rp.Credentials(), vfs.MayWrite); err != nil { + return nil, err + } // TODO(b/134676337): Support sockets. return nil, syserror.ECONNREFUSED diff --git a/pkg/sentry/fsimpl/kernfs/filesystem.go b/pkg/sentry/fsimpl/kernfs/filesystem.go index 40c1b2104..4a12ae245 100644 --- a/pkg/sentry/fsimpl/kernfs/filesystem.go +++ b/pkg/sentry/fsimpl/kernfs/filesystem.go @@ -768,12 +768,15 @@ func (fs *Filesystem) UnlinkAt(ctx context.Context, rp *vfs.ResolvingPath) error // BoundEndpointAt implements FilesystemImpl.BoundEndpointAt. func (fs *Filesystem) BoundEndpointAt(ctx context.Context, rp *vfs.ResolvingPath, opts vfs.BoundEndpointOptions) (transport.BoundEndpoint, error) { fs.mu.RLock() - _, _, err := fs.walkExistingLocked(ctx, rp) + _, inode, err := fs.walkExistingLocked(ctx, rp) fs.mu.RUnlock() fs.processDeferredDecRefs() if err != nil { return nil, err } + if err := inode.CheckPermissions(ctx, rp.Credentials(), vfs.MayWrite); err != nil { + return nil, err + } return nil, syserror.ECONNREFUSED } diff --git a/pkg/sentry/fsimpl/tmpfs/filesystem.go b/pkg/sentry/fsimpl/tmpfs/filesystem.go index 388b98bef..36ffcb592 100644 --- a/pkg/sentry/fsimpl/tmpfs/filesystem.go +++ b/pkg/sentry/fsimpl/tmpfs/filesystem.go @@ -704,6 +704,9 @@ func (fs *filesystem) BoundEndpointAt(ctx context.Context, rp *vfs.ResolvingPath if err != nil { return nil, err } + if err := d.inode.checkPermissions(rp.Credentials(), vfs.MayWrite); err != nil { + return nil, err + } switch impl := d.inode.impl.(type) { case *socketFile: return impl.ep, nil -- cgit v1.2.3