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authorFabricio Voznika <fvoznika@google.com>2020-04-08 13:33:44 -0700
committergVisor bot <gvisor-bot@google.com>2020-04-08 13:34:44 -0700
commitb30130567d81157e39b692e0116f86015f0bcc71 (patch)
treeb350c004e752228bb75ac621f0de4539bffdf471
parent71c7e24e5cb8641f4cb98b5fc848ae2033b29eac (diff)
Enable SubprocessExited and SubprocessZombie for gVisor
Updates #164 PiperOrigin-RevId: 305544029
-rw-r--r--pkg/sentry/fs/proc/task.go28
-rw-r--r--pkg/sentry/fsimpl/proc/task.go16
-rw-r--r--pkg/sentry/fsimpl/proc/task_files.go56
-rw-r--r--test/syscalls/linux/proc.cc31
4 files changed, 90 insertions, 41 deletions
diff --git a/pkg/sentry/fs/proc/task.go b/pkg/sentry/fs/proc/task.go
index d6c5dd2c1..4d42eac83 100644
--- a/pkg/sentry/fs/proc/task.go
+++ b/pkg/sentry/fs/proc/task.go
@@ -57,6 +57,16 @@ func getTaskMM(t *kernel.Task) (*mm.MemoryManager, error) {
return m, nil
}
+func checkTaskState(t *kernel.Task) error {
+ switch t.ExitState() {
+ case kernel.TaskExitZombie:
+ return syserror.EACCES
+ case kernel.TaskExitDead:
+ return syserror.ESRCH
+ }
+ return nil
+}
+
// taskDir represents a task-level directory.
//
// +stateify savable
@@ -254,11 +264,12 @@ func newExe(t *kernel.Task, msrc *fs.MountSource) *fs.Inode {
}
func (e *exe) executable() (file fsbridge.File, err error) {
+ if err := checkTaskState(e.t); err != nil {
+ return nil, err
+ }
e.t.WithMuLocked(func(t *kernel.Task) {
mm := t.MemoryManager()
if mm == nil {
- // TODO(b/34851096): Check shouldn't allow Readlink once the
- // Task is zombied.
err = syserror.EACCES
return
}
@@ -268,7 +279,7 @@ func (e *exe) executable() (file fsbridge.File, err error) {
// (with locks held).
file = mm.Executable()
if file == nil {
- err = syserror.ENOENT
+ err = syserror.ESRCH
}
})
return
@@ -313,11 +324,22 @@ func newNamespaceSymlink(t *kernel.Task, msrc *fs.MountSource, name string) *fs.
return newProcInode(t, n, msrc, fs.Symlink, t)
}
+// Readlink reads the symlink value.
+func (n *namespaceSymlink) Readlink(ctx context.Context, inode *fs.Inode) (string, error) {
+ if err := checkTaskState(n.t); err != nil {
+ return "", err
+ }
+ return n.Symlink.Readlink(ctx, inode)
+}
+
// Getlink implements fs.InodeOperations.Getlink.
func (n *namespaceSymlink) Getlink(ctx context.Context, inode *fs.Inode) (*fs.Dirent, error) {
if !kernel.ContextCanTrace(ctx, n.t, false) {
return nil, syserror.EACCES
}
+ if err := checkTaskState(n.t); err != nil {
+ return nil, err
+ }
// Create a new regular file to fake the namespace file.
iops := fsutil.NewNoReadWriteFileInode(ctx, fs.RootOwner, fs.FilePermsFromMode(0777), linux.PROC_SUPER_MAGIC)
diff --git a/pkg/sentry/fsimpl/proc/task.go b/pkg/sentry/fsimpl/proc/task.go
index aee2a4392..888afc0fd 100644
--- a/pkg/sentry/fsimpl/proc/task.go
+++ b/pkg/sentry/fsimpl/proc/task.go
@@ -214,22 +214,6 @@ func newIO(t *kernel.Task, isThreadGroup bool) *ioData {
return &ioData{ioUsage: t}
}
-func newNamespaceSymlink(task *kernel.Task, ino uint64, ns string) *kernfs.Dentry {
- // Namespace symlinks should contain the namespace name and the inode number
- // for the namespace instance, so for example user:[123456]. We currently fake
- // the inode number by sticking the symlink inode in its place.
- target := fmt.Sprintf("%s:[%d]", ns, ino)
-
- inode := &kernfs.StaticSymlink{}
- // Note: credentials are overridden by taskOwnedInode.
- inode.Init(task.Credentials(), ino, target)
-
- taskInode := &taskOwnedInode{Inode: inode, owner: task}
- d := &kernfs.Dentry{}
- d.Init(taskInode)
- return d
-}
-
// newCgroupData creates inode that shows cgroup information.
// From man 7 cgroups: "For each cgroup hierarchy of which the process is a
// member, there is one entry containing three colon-separated fields:
diff --git a/pkg/sentry/fsimpl/proc/task_files.go b/pkg/sentry/fsimpl/proc/task_files.go
index 88ea6a6d8..2c6f8bdfc 100644
--- a/pkg/sentry/fsimpl/proc/task_files.go
+++ b/pkg/sentry/fsimpl/proc/task_files.go
@@ -64,6 +64,16 @@ func getMMIncRef(task *kernel.Task) (*mm.MemoryManager, error) {
return m, nil
}
+func checkTaskState(t *kernel.Task) error {
+ switch t.ExitState() {
+ case kernel.TaskExitZombie:
+ return syserror.EACCES
+ case kernel.TaskExitDead:
+ return syserror.ESRCH
+ }
+ return nil
+}
+
type bufferWriter struct {
buf *bytes.Buffer
}
@@ -628,11 +638,13 @@ func (s *exeSymlink) Getlink(ctx context.Context) (vfs.VirtualDentry, string, er
}
func (s *exeSymlink) executable() (file fsbridge.File, err error) {
+ if err := checkTaskState(s.task); err != nil {
+ return nil, err
+ }
+
s.task.WithMuLocked(func(t *kernel.Task) {
mm := t.MemoryManager()
if mm == nil {
- // TODO(b/34851096): Check shouldn't allow Readlink once the
- // Task is zombied.
err = syserror.EACCES
return
}
@@ -642,7 +654,7 @@ func (s *exeSymlink) executable() (file fsbridge.File, err error) {
// (with locks held).
file = mm.Executable()
if file == nil {
- err = syserror.ENOENT
+ err = syserror.ESRCH
}
})
return
@@ -709,3 +721,41 @@ func (i *mountsData) Generate(ctx context.Context, buf *bytes.Buffer) error {
i.task.Kernel().VFS().GenerateProcMounts(ctx, rootDir, buf)
return nil
}
+
+type namespaceSymlink struct {
+ kernfs.StaticSymlink
+
+ task *kernel.Task
+}
+
+func newNamespaceSymlink(task *kernel.Task, ino uint64, ns string) *kernfs.Dentry {
+ // Namespace symlinks should contain the namespace name and the inode number
+ // for the namespace instance, so for example user:[123456]. We currently fake
+ // the inode number by sticking the symlink inode in its place.
+ target := fmt.Sprintf("%s:[%d]", ns, ino)
+
+ inode := &namespaceSymlink{task: task}
+ // Note: credentials are overridden by taskOwnedInode.
+ inode.Init(task.Credentials(), ino, target)
+
+ taskInode := &taskOwnedInode{Inode: inode, owner: task}
+ d := &kernfs.Dentry{}
+ d.Init(taskInode)
+ return d
+}
+
+// Readlink implements Inode.
+func (s *namespaceSymlink) Readlink(ctx context.Context) (string, error) {
+ if err := checkTaskState(s.task); err != nil {
+ return "", err
+ }
+ return s.StaticSymlink.Readlink(ctx)
+}
+
+// Getlink implements Inode.Getlink.
+func (s *namespaceSymlink) Getlink(ctx context.Context) (vfs.VirtualDentry, string, error) {
+ if err := checkTaskState(s.task); err != nil {
+ return vfs.VirtualDentry{}, "", err
+ }
+ return s.StaticSymlink.Getlink(ctx)
+}
diff --git a/test/syscalls/linux/proc.cc b/test/syscalls/linux/proc.cc
index 5a70f6c3b..da98e1f66 100644
--- a/test/syscalls/linux/proc.cc
+++ b/test/syscalls/linux/proc.cc
@@ -1326,8 +1326,6 @@ TEST(ProcPidSymlink, SubprocessRunning) {
SyscallSucceedsWithValue(sizeof(buf)));
}
-// FIXME(gvisor.dev/issue/164): Inconsistent behavior between gVisor and linux
-// on proc files.
TEST(ProcPidSymlink, SubprocessZombied) {
ASSERT_NO_ERRNO(SetCapability(CAP_DAC_OVERRIDE, false));
ASSERT_NO_ERRNO(SetCapability(CAP_DAC_READ_SEARCH, false));
@@ -1337,7 +1335,7 @@ TEST(ProcPidSymlink, SubprocessZombied) {
int want = EACCES;
if (!IsRunningOnGvisor()) {
auto version = ASSERT_NO_ERRNO_AND_VALUE(GetKernelVersion());
- if (version.major == 4 && version.minor > 3) {
+ if (version.major > 4 || (version.major == 4 && version.minor > 3)) {
want = ENOENT;
}
}
@@ -1350,30 +1348,25 @@ TEST(ProcPidSymlink, SubprocessZombied) {
SyscallFailsWithErrno(want));
}
- // FIXME(gvisor.dev/issue/164): Inconsistent behavior between gVisor and linux
- // on proc files.
+ // FIXME(gvisor.dev/issue/164): Inconsistent behavior between linux on proc
+ // files.
//
// ~4.3: Syscall fails with EACCES.
- // 4.17 & gVisor: Syscall succeeds and returns 1.
+ // 4.17: Syscall succeeds and returns 1.
//
- // EXPECT_THAT(ReadlinkWhileZombied("ns/pid", buf, sizeof(buf)),
- // SyscallFailsWithErrno(EACCES));
+ if (!IsRunningOnGvisor()) {
+ return;
+ }
- // FIXME(gvisor.dev/issue/164): Inconsistent behavior between gVisor and linux
- // on proc files.
- //
- // ~4.3: Syscall fails with EACCES.
- // 4.17 & gVisor: Syscall succeeds and returns 1.
- //
- // EXPECT_THAT(ReadlinkWhileZombied("ns/user", buf, sizeof(buf)),
- // SyscallFailsWithErrno(EACCES));
+ EXPECT_THAT(ReadlinkWhileZombied("ns/pid", buf, sizeof(buf)),
+ SyscallFailsWithErrno(want));
+
+ EXPECT_THAT(ReadlinkWhileZombied("ns/user", buf, sizeof(buf)),
+ SyscallFailsWithErrno(want));
}
// Test whether /proc/PID/ symlinks can be read for an exited process.
TEST(ProcPidSymlink, SubprocessExited) {
- // FIXME(gvisor.dev/issue/164): These all succeed on gVisor.
- SKIP_IF(IsRunningOnGvisor());
-
char buf[1];
EXPECT_THAT(ReadlinkWhileExited("exe", buf, sizeof(buf)),