diff options
Diffstat (limited to 'pkg/sentry/fs/proc')
| -rw-r--r-- | pkg/sentry/fs/proc/inode.go | 40 | ||||
| -rw-r--r-- | pkg/sentry/fs/proc/net.go | 34 | ||||
| -rw-r--r-- | pkg/sentry/fs/proc/task.go | 17 |
3 files changed, 63 insertions, 28 deletions
diff --git a/pkg/sentry/fs/proc/inode.go b/pkg/sentry/fs/proc/inode.go index 379569823..986bc0a45 100644 --- a/pkg/sentry/fs/proc/inode.go +++ b/pkg/sentry/fs/proc/inode.go @@ -21,11 +21,14 @@ import ( "gvisor.googlesource.com/gvisor/pkg/sentry/fs/fsutil" "gvisor.googlesource.com/gvisor/pkg/sentry/fs/proc/device" "gvisor.googlesource.com/gvisor/pkg/sentry/kernel" + "gvisor.googlesource.com/gvisor/pkg/sentry/kernel/auth" + "gvisor.googlesource.com/gvisor/pkg/sentry/mm" "gvisor.googlesource.com/gvisor/pkg/sentry/usermem" ) // taskOwnedInodeOps wraps an fs.InodeOperations and overrides the UnstableAttr -// method to return the task as the owner. +// method to return either the task or root as the owner, depending on the +// task's dumpability. // // +stateify savable type taskOwnedInodeOps struct { @@ -41,9 +44,42 @@ func (i *taskOwnedInodeOps) UnstableAttr(ctx context.Context, inode *fs.Inode) ( if err != nil { return fs.UnstableAttr{}, err } - // Set the task owner as the file owner. + + // By default, set the task owner as the file owner. creds := i.t.Credentials() uattr.Owner = fs.FileOwner{creds.EffectiveKUID, creds.EffectiveKGID} + + // Linux doesn't apply dumpability adjustments to world + // readable/executable directories so that applications can stat + // /proc/PID to determine the effective UID of a process. See + // fs/proc/base.c:task_dump_owner. + if fs.IsDir(inode.StableAttr) && uattr.Perms == fs.FilePermsFromMode(0555) { + return uattr, nil + } + + // If the task is not dumpable, then root (in the namespace preferred) + // owns the file. + var m *mm.MemoryManager + i.t.WithMuLocked(func(t *kernel.Task) { + m = t.MemoryManager() + }) + + if m == nil { + uattr.Owner.UID = auth.RootKUID + uattr.Owner.GID = auth.RootKGID + } else if m.Dumpability() != mm.UserDumpable { + if kuid := creds.UserNamespace.MapToKUID(auth.RootUID); kuid.Ok() { + uattr.Owner.UID = kuid + } else { + uattr.Owner.UID = auth.RootKUID + } + if kgid := creds.UserNamespace.MapToKGID(auth.RootGID); kgid.Ok() { + uattr.Owner.GID = kgid + } else { + uattr.Owner.GID = auth.RootKGID + } + } + return uattr, nil } diff --git a/pkg/sentry/fs/proc/net.go b/pkg/sentry/fs/proc/net.go index 4a107c739..034950158 100644 --- a/pkg/sentry/fs/proc/net.go +++ b/pkg/sentry/fs/proc/net.go @@ -27,6 +27,7 @@ import ( "gvisor.googlesource.com/gvisor/pkg/sentry/fs/ramfs" "gvisor.googlesource.com/gvisor/pkg/sentry/inet" "gvisor.googlesource.com/gvisor/pkg/sentry/kernel" + "gvisor.googlesource.com/gvisor/pkg/sentry/socket" "gvisor.googlesource.com/gvisor/pkg/sentry/socket/unix" "gvisor.googlesource.com/gvisor/pkg/sentry/socket/unix/transport" ) @@ -213,17 +214,18 @@ func (n *netUnix) ReadSeqFileData(ctx context.Context, h seqfile.SeqHandle) ([]s fmt.Fprintf(&buf, "Num RefCount Protocol Flags Type St Inode Path\n") // Entries - for _, sref := range n.k.ListSockets(linux.AF_UNIX) { - s := sref.Get() + for _, se := range n.k.ListSockets() { + s := se.Sock.Get() if s == nil { - log.Debugf("Couldn't resolve weakref %v in socket table, racing with destruction?", sref) + log.Debugf("Couldn't resolve weakref %v in socket table, racing with destruction?", se.Sock) continue } sfile := s.(*fs.File) - sops, ok := sfile.FileOperations.(*unix.SocketOperations) - if !ok { - panic(fmt.Sprintf("Found non-unix socket file in unix socket table: %+v", sfile)) + if family, _, _ := sfile.FileOperations.(socket.Socket).Type(); family != linux.AF_UNIX { + // Not a unix socket. + continue } + sops := sfile.FileOperations.(*unix.SocketOperations) addr, err := sops.Endpoint().GetLocalAddress() if err != nil { @@ -240,24 +242,6 @@ func (n *netUnix) ReadSeqFileData(ctx context.Context, h seqfile.SeqHandle) ([]s } } - var sockState int - switch sops.Endpoint().Type() { - case linux.SOCK_DGRAM: - sockState = linux.SS_CONNECTING - // Unlike Linux, we don't have unbound connection-less sockets, - // so no SS_DISCONNECTING. - - case linux.SOCK_SEQPACKET: - fallthrough - case linux.SOCK_STREAM: - // Connectioned. - if sops.Endpoint().(transport.ConnectingEndpoint).Connected() { - sockState = linux.SS_CONNECTED - } else { - sockState = linux.SS_UNCONNECTED - } - } - // In the socket entry below, the value for the 'Num' field requires // some consideration. Linux prints the address to the struct // unix_sock representing a socket in the kernel, but may redact the @@ -282,7 +266,7 @@ func (n *netUnix) ReadSeqFileData(ctx context.Context, h seqfile.SeqHandle) ([]s 0, // Protocol, always 0 for UDS. sockFlags, // Flags. sops.Endpoint().Type(), // Type. - sockState, // State. + sops.State(), // State. sfile.InodeID(), // Inode. ) diff --git a/pkg/sentry/fs/proc/task.go b/pkg/sentry/fs/proc/task.go index 77e03d349..21a965f90 100644 --- a/pkg/sentry/fs/proc/task.go +++ b/pkg/sentry/fs/proc/task.go @@ -96,7 +96,7 @@ func (p *proc) newTaskDir(t *kernel.Task, msrc *fs.MountSource, showSubtasks boo contents["cgroup"] = newCGroupInode(t, msrc, p.cgroupControllers) } - // TODO(b/31916171): Set EUID/EGID based on dumpability. + // N.B. taskOwnedInodeOps enforces dumpability-based ownership. d := &taskDir{ Dir: *ramfs.NewDir(t, contents, fs.RootOwner, fs.FilePermsFromMode(0555)), t: t, @@ -667,6 +667,21 @@ func newComm(t *kernel.Task, msrc *fs.MountSource) *fs.Inode { return newProcInode(c, msrc, fs.SpecialFile, t) } +// Check implements fs.InodeOperations.Check. +func (c *comm) Check(ctx context.Context, inode *fs.Inode, p fs.PermMask) bool { + // This file can always be read or written by members of the same + // thread group. See fs/proc/base.c:proc_tid_comm_permission. + // + // N.B. This check is currently a no-op as we don't yet support writing + // and this file is world-readable anyways. + t := kernel.TaskFromContext(ctx) + if t != nil && t.ThreadGroup() == c.t.ThreadGroup() && !p.Execute { + return true + } + + return fs.ContextCanAccessFile(ctx, inode, p) +} + // GetFile implements fs.InodeOperations.GetFile. func (c *comm) GetFile(ctx context.Context, dirent *fs.Dirent, flags fs.FileFlags) (*fs.File, error) { return fs.NewFile(ctx, dirent, flags, &commFile{t: c.t}), nil |