summaryrefslogtreecommitdiffhomepage
path: root/pkg/sentry/fsimpl/proc/task_files.go
diff options
context:
space:
mode:
Diffstat (limited to 'pkg/sentry/fsimpl/proc/task_files.go')
-rw-r--r--pkg/sentry/fsimpl/proc/task_files.go315
1 files changed, 285 insertions, 30 deletions
diff --git a/pkg/sentry/fsimpl/proc/task_files.go b/pkg/sentry/fsimpl/proc/task_files.go
index 93f0e1aa8..7bc352ae9 100644
--- a/pkg/sentry/fsimpl/proc/task_files.go
+++ b/pkg/sentry/fsimpl/proc/task_files.go
@@ -17,15 +17,20 @@ package proc
import (
"bytes"
"fmt"
+ "io"
"gvisor.dev/gvisor/pkg/abi/linux"
"gvisor.dev/gvisor/pkg/sentry/context"
"gvisor.dev/gvisor/pkg/sentry/fsimpl/kernfs"
"gvisor.dev/gvisor/pkg/sentry/kernel"
+ "gvisor.dev/gvisor/pkg/sentry/kernel/auth"
"gvisor.dev/gvisor/pkg/sentry/limits"
"gvisor.dev/gvisor/pkg/sentry/mm"
+ "gvisor.dev/gvisor/pkg/sentry/safemem"
"gvisor.dev/gvisor/pkg/sentry/usage"
"gvisor.dev/gvisor/pkg/sentry/usermem"
+ "gvisor.dev/gvisor/pkg/sentry/vfs"
+ "gvisor.dev/gvisor/pkg/syserror"
)
// mm gets the kernel task's MemoryManager. No additional reference is taken on
@@ -41,6 +46,256 @@ func getMM(task *kernel.Task) *mm.MemoryManager {
return tmm
}
+// getMMIncRef returns t's MemoryManager. If getMMIncRef succeeds, the
+// MemoryManager's users count is incremented, and must be decremented by the
+// caller when it is no longer in use.
+func getMMIncRef(task *kernel.Task) (*mm.MemoryManager, error) {
+ if task.ExitState() == kernel.TaskExitDead {
+ return nil, syserror.ESRCH
+ }
+ var m *mm.MemoryManager
+ task.WithMuLocked(func(t *kernel.Task) {
+ m = t.MemoryManager()
+ })
+ if m == nil || !m.IncUsers() {
+ return nil, io.EOF
+ }
+ return m, nil
+}
+
+type bufferWriter struct {
+ buf *bytes.Buffer
+}
+
+// WriteFromBlocks writes up to srcs.NumBytes() bytes from srcs and returns
+// the number of bytes written. It may return a partial write without an
+// error (i.e. (n, nil) where 0 < n < srcs.NumBytes()). It should not
+// return a full write with an error (i.e. srcs.NumBytes(), err) where err
+// != nil).
+func (w *bufferWriter) WriteFromBlocks(srcs safemem.BlockSeq) (uint64, error) {
+ written := srcs.NumBytes()
+ for !srcs.IsEmpty() {
+ w.buf.Write(srcs.Head().ToSlice())
+ srcs = srcs.Tail()
+ }
+ return written, nil
+}
+
+// auxvData implements vfs.DynamicBytesSource for /proc/[pid]/auxv.
+//
+// +stateify savable
+type auxvData struct {
+ kernfs.DynamicBytesFile
+
+ task *kernel.Task
+}
+
+var _ dynamicInode = (*auxvData)(nil)
+
+// Generate implements vfs.DynamicBytesSource.Generate.
+func (d *auxvData) Generate(ctx context.Context, buf *bytes.Buffer) error {
+ m, err := getMMIncRef(d.task)
+ if err != nil {
+ return err
+ }
+ defer m.DecUsers(ctx)
+
+ // Space for buffer with AT_NULL (0) terminator at the end.
+ auxv := m.Auxv()
+ buf.Grow((len(auxv) + 1) * 16)
+ for _, e := range auxv {
+ var tmp [8]byte
+ usermem.ByteOrder.PutUint64(tmp[:], e.Key)
+ buf.Write(tmp[:])
+
+ usermem.ByteOrder.PutUint64(tmp[:], uint64(e.Value))
+ buf.Write(tmp[:])
+ }
+ return nil
+}
+
+// execArgType enumerates the types of exec arguments that are exposed through
+// proc.
+type execArgType int
+
+const (
+ cmdlineDataArg execArgType = iota
+ environDataArg
+)
+
+// cmdlineData implements vfs.DynamicBytesSource for /proc/[pid]/cmdline.
+//
+// +stateify savable
+type cmdlineData struct {
+ kernfs.DynamicBytesFile
+
+ task *kernel.Task
+
+ // arg is the type of exec argument this file contains.
+ arg execArgType
+}
+
+var _ dynamicInode = (*cmdlineData)(nil)
+
+// Generate implements vfs.DynamicBytesSource.Generate.
+func (d *cmdlineData) Generate(ctx context.Context, buf *bytes.Buffer) error {
+ m, err := getMMIncRef(d.task)
+ if err != nil {
+ return err
+ }
+ defer m.DecUsers(ctx)
+
+ // Figure out the bounds of the exec arg we are trying to read.
+ var ar usermem.AddrRange
+ switch d.arg {
+ case cmdlineDataArg:
+ ar = usermem.AddrRange{
+ Start: m.ArgvStart(),
+ End: m.ArgvEnd(),
+ }
+ case environDataArg:
+ ar = usermem.AddrRange{
+ Start: m.EnvvStart(),
+ End: m.EnvvEnd(),
+ }
+ default:
+ panic(fmt.Sprintf("unknown exec arg type %v", d.arg))
+ }
+ if ar.Start == 0 || ar.End == 0 {
+ // Don't attempt to read before the start/end are set up.
+ return io.EOF
+ }
+
+ // N.B. Technically this should be usermem.IOOpts.IgnorePermissions = true
+ // until Linux 4.9 (272ddc8b3735 "proc: don't use FOLL_FORCE for reading
+ // cmdline and environment").
+ writer := &bufferWriter{buf: buf}
+ if n, err := m.CopyInTo(ctx, usermem.AddrRangeSeqOf(ar), writer, usermem.IOOpts{}); n == 0 || err != nil {
+ // Nothing to copy or something went wrong.
+ return err
+ }
+
+ // On Linux, if the NULL byte at the end of the argument vector has been
+ // overwritten, it continues reading the environment vector as part of
+ // the argument vector.
+ if d.arg == cmdlineDataArg && buf.Bytes()[buf.Len()-1] != 0 {
+ if end := bytes.IndexByte(buf.Bytes(), 0); end != -1 {
+ // If we found a NULL character somewhere else in argv, truncate the
+ // return up to the NULL terminator (including it).
+ buf.Truncate(end)
+ return nil
+ }
+
+ // There is no NULL terminator in the string, return into envp.
+ arEnvv := usermem.AddrRange{
+ Start: m.EnvvStart(),
+ End: m.EnvvEnd(),
+ }
+
+ // Upstream limits the returned amount to one page of slop.
+ // https://elixir.bootlin.com/linux/v4.20/source/fs/proc/base.c#L208
+ // we'll return one page total between argv and envp because of the
+ // above page restrictions.
+ if buf.Len() >= usermem.PageSize {
+ // Returned at least one page already, nothing else to add.
+ return nil
+ }
+ remaining := usermem.PageSize - buf.Len()
+ if int(arEnvv.Length()) > remaining {
+ end, ok := arEnvv.Start.AddLength(uint64(remaining))
+ if !ok {
+ return syserror.EFAULT
+ }
+ arEnvv.End = end
+ }
+ if _, err := m.CopyInTo(ctx, usermem.AddrRangeSeqOf(arEnvv), writer, usermem.IOOpts{}); err != nil {
+ return err
+ }
+
+ // Linux will return envp up to and including the first NULL character,
+ // so find it.
+ if end := bytes.IndexByte(buf.Bytes()[ar.Length():], 0); end != -1 {
+ buf.Truncate(end)
+ }
+ }
+
+ return nil
+}
+
+// +stateify savable
+type commInode struct {
+ kernfs.DynamicBytesFile
+
+ task *kernel.Task
+}
+
+func newComm(task *kernel.Task, ino uint64, perm linux.FileMode) *kernfs.Dentry {
+ inode := &commInode{task: task}
+ inode.DynamicBytesFile.Init(task.Credentials(), ino, &commData{task: task}, perm)
+
+ d := &kernfs.Dentry{}
+ d.Init(inode)
+ return d
+}
+
+func (i *commInode) CheckPermissions(ctx context.Context, creds *auth.Credentials, ats vfs.AccessTypes) error {
+ // 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() == i.task.ThreadGroup() && !ats.MayExec() {
+ return nil
+ }
+
+ return i.DynamicBytesFile.CheckPermissions(ctx, creds, ats)
+}
+
+// commData implements vfs.DynamicBytesSource for /proc/[pid]/comm.
+//
+// +stateify savable
+type commData struct {
+ kernfs.DynamicBytesFile
+
+ task *kernel.Task
+}
+
+var _ dynamicInode = (*commData)(nil)
+
+// Generate implements vfs.DynamicBytesSource.Generate.
+func (d *commData) Generate(ctx context.Context, buf *bytes.Buffer) error {
+ buf.WriteString(d.task.Name())
+ buf.WriteString("\n")
+ return nil
+}
+
+// idMapData implements vfs.DynamicBytesSource for /proc/[pid]/{gid_map|uid_map}.
+//
+// +stateify savable
+type idMapData struct {
+ kernfs.DynamicBytesFile
+
+ task *kernel.Task
+ gids bool
+}
+
+var _ dynamicInode = (*idMapData)(nil)
+
+// Generate implements vfs.DynamicBytesSource.Generate.
+func (d *idMapData) Generate(ctx context.Context, buf *bytes.Buffer) error {
+ var entries []auth.IDMapEntry
+ if d.gids {
+ entries = d.task.UserNamespace().GIDMap()
+ } else {
+ entries = d.task.UserNamespace().UIDMap()
+ }
+ for _, e := range entries {
+ fmt.Fprintf(buf, "%10d %10d %10d\n", e.FirstID, e.FirstParentID, e.Length)
+ }
+ return nil
+}
+
// mapsData implements vfs.DynamicBytesSource for /proc/[pid]/maps.
//
// +stateify savable
@@ -83,7 +338,7 @@ func (d *smapsData) Generate(ctx context.Context, buf *bytes.Buffer) error {
type taskStatData struct {
kernfs.DynamicBytesFile
- t *kernel.Task
+ task *kernel.Task
// If tgstats is true, accumulate fault stats (not implemented) and CPU
// time across all tasks in t's thread group.
@@ -98,40 +353,40 @@ var _ dynamicInode = (*taskStatData)(nil)
// Generate implements vfs.DynamicBytesSource.Generate.
func (s *taskStatData) Generate(ctx context.Context, buf *bytes.Buffer) error {
- fmt.Fprintf(buf, "%d ", s.pidns.IDOfTask(s.t))
- fmt.Fprintf(buf, "(%s) ", s.t.Name())
- fmt.Fprintf(buf, "%c ", s.t.StateStatus()[0])
+ fmt.Fprintf(buf, "%d ", s.pidns.IDOfTask(s.task))
+ fmt.Fprintf(buf, "(%s) ", s.task.Name())
+ fmt.Fprintf(buf, "%c ", s.task.StateStatus()[0])
ppid := kernel.ThreadID(0)
- if parent := s.t.Parent(); parent != nil {
+ if parent := s.task.Parent(); parent != nil {
ppid = s.pidns.IDOfThreadGroup(parent.ThreadGroup())
}
fmt.Fprintf(buf, "%d ", ppid)
- fmt.Fprintf(buf, "%d ", s.pidns.IDOfProcessGroup(s.t.ThreadGroup().ProcessGroup()))
- fmt.Fprintf(buf, "%d ", s.pidns.IDOfSession(s.t.ThreadGroup().Session()))
+ fmt.Fprintf(buf, "%d ", s.pidns.IDOfProcessGroup(s.task.ThreadGroup().ProcessGroup()))
+ fmt.Fprintf(buf, "%d ", s.pidns.IDOfSession(s.task.ThreadGroup().Session()))
fmt.Fprintf(buf, "0 0 " /* tty_nr tpgid */)
fmt.Fprintf(buf, "0 " /* flags */)
fmt.Fprintf(buf, "0 0 0 0 " /* minflt cminflt majflt cmajflt */)
var cputime usage.CPUStats
if s.tgstats {
- cputime = s.t.ThreadGroup().CPUStats()
+ cputime = s.task.ThreadGroup().CPUStats()
} else {
- cputime = s.t.CPUStats()
+ cputime = s.task.CPUStats()
}
fmt.Fprintf(buf, "%d %d ", linux.ClockTFromDuration(cputime.UserTime), linux.ClockTFromDuration(cputime.SysTime))
- cputime = s.t.ThreadGroup().JoinedChildCPUStats()
+ cputime = s.task.ThreadGroup().JoinedChildCPUStats()
fmt.Fprintf(buf, "%d %d ", linux.ClockTFromDuration(cputime.UserTime), linux.ClockTFromDuration(cputime.SysTime))
- fmt.Fprintf(buf, "%d %d ", s.t.Priority(), s.t.Niceness())
- fmt.Fprintf(buf, "%d ", s.t.ThreadGroup().Count())
+ fmt.Fprintf(buf, "%d %d ", s.task.Priority(), s.task.Niceness())
+ fmt.Fprintf(buf, "%d ", s.task.ThreadGroup().Count())
// itrealvalue. Since kernel 2.6.17, this field is no longer
// maintained, and is hard coded as 0.
fmt.Fprintf(buf, "0 ")
// Start time is relative to boot time, expressed in clock ticks.
- fmt.Fprintf(buf, "%d ", linux.ClockTFromDuration(s.t.StartTime().Sub(s.t.Kernel().Timekeeper().BootTime())))
+ fmt.Fprintf(buf, "%d ", linux.ClockTFromDuration(s.task.StartTime().Sub(s.task.Kernel().Timekeeper().BootTime())))
var vss, rss uint64
- s.t.WithMuLocked(func(t *kernel.Task) {
+ s.task.WithMuLocked(func(t *kernel.Task) {
if mm := t.MemoryManager(); mm != nil {
vss = mm.VirtualMemorySize()
rss = mm.ResidentSetSize()
@@ -140,14 +395,14 @@ func (s *taskStatData) Generate(ctx context.Context, buf *bytes.Buffer) error {
fmt.Fprintf(buf, "%d %d ", vss, rss/usermem.PageSize)
// rsslim.
- fmt.Fprintf(buf, "%d ", s.t.ThreadGroup().Limits().Get(limits.Rss).Cur)
+ fmt.Fprintf(buf, "%d ", s.task.ThreadGroup().Limits().Get(limits.Rss).Cur)
fmt.Fprintf(buf, "0 0 0 0 0 " /* startcode endcode startstack kstkesp kstkeip */)
fmt.Fprintf(buf, "0 0 0 0 0 " /* signal blocked sigignore sigcatch wchan */)
fmt.Fprintf(buf, "0 0 " /* nswap cnswap */)
terminationSignal := linux.Signal(0)
- if s.t == s.t.ThreadGroup().Leader() {
- terminationSignal = s.t.ThreadGroup().TerminationSignal()
+ if s.task == s.task.ThreadGroup().Leader() {
+ terminationSignal = s.task.ThreadGroup().TerminationSignal()
}
fmt.Fprintf(buf, "%d ", terminationSignal)
fmt.Fprintf(buf, "0 0 0 " /* processor rt_priority policy */)
@@ -164,7 +419,7 @@ func (s *taskStatData) Generate(ctx context.Context, buf *bytes.Buffer) error {
type statmData struct {
kernfs.DynamicBytesFile
- t *kernel.Task
+ task *kernel.Task
}
var _ dynamicInode = (*statmData)(nil)
@@ -172,7 +427,7 @@ var _ dynamicInode = (*statmData)(nil)
// Generate implements vfs.DynamicBytesSource.Generate.
func (s *statmData) Generate(ctx context.Context, buf *bytes.Buffer) error {
var vss, rss uint64
- s.t.WithMuLocked(func(t *kernel.Task) {
+ s.task.WithMuLocked(func(t *kernel.Task) {
if mm := t.MemoryManager(); mm != nil {
vss = mm.VirtualMemorySize()
rss = mm.ResidentSetSize()
@@ -189,7 +444,7 @@ func (s *statmData) Generate(ctx context.Context, buf *bytes.Buffer) error {
type statusData struct {
kernfs.DynamicBytesFile
- t *kernel.Task
+ task *kernel.Task
pidns *kernel.PIDNamespace
}
@@ -197,23 +452,23 @@ var _ dynamicInode = (*statusData)(nil)
// Generate implements vfs.DynamicBytesSource.Generate.
func (s *statusData) Generate(ctx context.Context, buf *bytes.Buffer) error {
- fmt.Fprintf(buf, "Name:\t%s\n", s.t.Name())
- fmt.Fprintf(buf, "State:\t%s\n", s.t.StateStatus())
- fmt.Fprintf(buf, "Tgid:\t%d\n", s.pidns.IDOfThreadGroup(s.t.ThreadGroup()))
- fmt.Fprintf(buf, "Pid:\t%d\n", s.pidns.IDOfTask(s.t))
+ fmt.Fprintf(buf, "Name:\t%s\n", s.task.Name())
+ fmt.Fprintf(buf, "State:\t%s\n", s.task.StateStatus())
+ fmt.Fprintf(buf, "Tgid:\t%d\n", s.pidns.IDOfThreadGroup(s.task.ThreadGroup()))
+ fmt.Fprintf(buf, "Pid:\t%d\n", s.pidns.IDOfTask(s.task))
ppid := kernel.ThreadID(0)
- if parent := s.t.Parent(); parent != nil {
+ if parent := s.task.Parent(); parent != nil {
ppid = s.pidns.IDOfThreadGroup(parent.ThreadGroup())
}
fmt.Fprintf(buf, "PPid:\t%d\n", ppid)
tpid := kernel.ThreadID(0)
- if tracer := s.t.Tracer(); tracer != nil {
+ if tracer := s.task.Tracer(); tracer != nil {
tpid = s.pidns.IDOfTask(tracer)
}
fmt.Fprintf(buf, "TracerPid:\t%d\n", tpid)
var fds int
var vss, rss, data uint64
- s.t.WithMuLocked(func(t *kernel.Task) {
+ s.task.WithMuLocked(func(t *kernel.Task) {
if fdTable := t.FDTable(); fdTable != nil {
fds = fdTable.Size()
}
@@ -227,13 +482,13 @@ func (s *statusData) Generate(ctx context.Context, buf *bytes.Buffer) error {
fmt.Fprintf(buf, "VmSize:\t%d kB\n", vss>>10)
fmt.Fprintf(buf, "VmRSS:\t%d kB\n", rss>>10)
fmt.Fprintf(buf, "VmData:\t%d kB\n", data>>10)
- fmt.Fprintf(buf, "Threads:\t%d\n", s.t.ThreadGroup().Count())
- creds := s.t.Credentials()
+ fmt.Fprintf(buf, "Threads:\t%d\n", s.task.ThreadGroup().Count())
+ creds := s.task.Credentials()
fmt.Fprintf(buf, "CapInh:\t%016x\n", creds.InheritableCaps)
fmt.Fprintf(buf, "CapPrm:\t%016x\n", creds.PermittedCaps)
fmt.Fprintf(buf, "CapEff:\t%016x\n", creds.EffectiveCaps)
fmt.Fprintf(buf, "CapBnd:\t%016x\n", creds.BoundingCaps)
- fmt.Fprintf(buf, "Seccomp:\t%d\n", s.t.SeccompMode())
+ fmt.Fprintf(buf, "Seccomp:\t%d\n", s.task.SeccompMode())
// We unconditionally report a single NUMA node. See
// pkg/sentry/syscalls/linux/sys_mempolicy.go.
fmt.Fprintf(buf, "Mems_allowed:\t1\n")
generated by cgit v1.2.3 (git 2.39.1) at 2025-01-18 00:22:08 +0000