From 6b992edc8ab85070f50a6860b936b6cef82d48f8 Mon Sep 17 00:00:00 2001 From: Nayana Bidari Date: Tue, 1 Sep 2020 13:38:44 -0700 Subject: Fix panic when calling dup2(). PiperOrigin-RevId: 329572337 --- pkg/sentry/kernel/fd_table.go | 43 ++++++++++++++++---------------- pkg/sentry/kernel/fd_table_test.go | 8 +++--- pkg/sentry/kernel/fd_table_unsafe.go | 15 +++++------ pkg/sentry/syscalls/linux/sys_file.go | 12 ++++++--- pkg/sentry/syscalls/linux/sys_pipe.go | 2 +- pkg/sentry/syscalls/linux/sys_socket.go | 2 +- pkg/sentry/syscalls/linux/vfs2/fd.go | 4 +-- pkg/sentry/syscalls/linux/vfs2/ioctl.go | 4 +-- pkg/sentry/syscalls/linux/vfs2/pipe.go | 2 +- pkg/sentry/syscalls/linux/vfs2/socket.go | 2 +- 10 files changed, 49 insertions(+), 45 deletions(-) (limited to 'pkg') diff --git a/pkg/sentry/kernel/fd_table.go b/pkg/sentry/kernel/fd_table.go index 5773244ac..89223fa36 100644 --- a/pkg/sentry/kernel/fd_table.go +++ b/pkg/sentry/kernel/fd_table.go @@ -112,7 +112,7 @@ func (f *FDTable) loadDescriptorTable(m map[int32]descriptor) { ctx := context.Background() f.init() // Initialize table. for fd, d := range m { - f.setAll(fd, d.file, d.fileVFS2, d.flags) + f.setAll(ctx, fd, d.file, d.fileVFS2, d.flags) // Note that we do _not_ need to acquire a extra table reference here. The // table reference will already be accounted for in the file, so we drop the @@ -127,7 +127,7 @@ func (f *FDTable) loadDescriptorTable(m map[int32]descriptor) { } // drop drops the table reference. -func (f *FDTable) drop(file *fs.File) { +func (f *FDTable) drop(ctx context.Context, file *fs.File) { // Release locks. file.Dirent.Inode.LockCtx.Posix.UnlockRegion(f, lock.LockRange{0, lock.LockEOF}) @@ -145,14 +145,13 @@ func (f *FDTable) drop(file *fs.File) { d.InotifyEvent(ev, 0) // Drop the table reference. - file.DecRef(context.Background()) + file.DecRef(ctx) } // dropVFS2 drops the table reference. -func (f *FDTable) dropVFS2(file *vfs.FileDescription) { +func (f *FDTable) dropVFS2(ctx context.Context, file *vfs.FileDescription) { // Release any POSIX lock possibly held by the FDTable. Range {0, 0} means the // entire file. - ctx := context.Background() err := file.UnlockPOSIX(ctx, f, 0, 0, linux.SEEK_SET) if err != nil && err != syserror.ENOLCK { panic(fmt.Sprintf("UnlockPOSIX failed: %v", err)) @@ -289,15 +288,15 @@ func (f *FDTable) NewFDs(ctx context.Context, fd int32, files []*fs.File, flags // Install all entries. for i := fd; i < end && len(fds) < len(files); i++ { if d, _, _ := f.get(i); d == nil { - f.set(i, files[len(fds)], flags) // Set the descriptor. - fds = append(fds, i) // Record the file descriptor. + f.set(ctx, i, files[len(fds)], flags) // Set the descriptor. + fds = append(fds, i) // Record the file descriptor. } } // Failure? Unwind existing FDs. if len(fds) < len(files) { for _, i := range fds { - f.set(i, nil, FDFlags{}) // Zap entry. + f.set(ctx, i, nil, FDFlags{}) // Zap entry. } return nil, syscall.EMFILE } @@ -344,15 +343,15 @@ func (f *FDTable) NewFDsVFS2(ctx context.Context, fd int32, files []*vfs.FileDes // Install all entries. for i := fd; i < end && len(fds) < len(files); i++ { if d, _, _ := f.getVFS2(i); d == nil { - f.setVFS2(i, files[len(fds)], flags) // Set the descriptor. - fds = append(fds, i) // Record the file descriptor. + f.setVFS2(ctx, i, files[len(fds)], flags) // Set the descriptor. + fds = append(fds, i) // Record the file descriptor. } } // Failure? Unwind existing FDs. if len(fds) < len(files) { for _, i := range fds { - f.setVFS2(i, nil, FDFlags{}) // Zap entry. + f.setVFS2(ctx, i, nil, FDFlags{}) // Zap entry. } return nil, syscall.EMFILE } @@ -397,7 +396,7 @@ func (f *FDTable) NewFDVFS2(ctx context.Context, minfd int32, file *vfs.FileDesc } for fd < end { if d, _, _ := f.getVFS2(fd); d == nil { - f.setVFS2(fd, file, flags) + f.setVFS2(ctx, fd, file, flags) if fd == f.next { // Update next search start position. f.next = fd + 1 @@ -439,14 +438,14 @@ func (f *FDTable) newFDAt(ctx context.Context, fd int32, file *fs.File, fileVFS2 // Install the entry. f.mu.Lock() defer f.mu.Unlock() - f.setAll(fd, file, fileVFS2, flags) + f.setAll(ctx, fd, file, fileVFS2, flags) return nil } // SetFlags sets the flags for the given file descriptor. // // True is returned iff flags were changed. -func (f *FDTable) SetFlags(fd int32, flags FDFlags) error { +func (f *FDTable) SetFlags(ctx context.Context, fd int32, flags FDFlags) error { if fd < 0 { // Don't accept negative FDs. return syscall.EBADF @@ -462,14 +461,14 @@ func (f *FDTable) SetFlags(fd int32, flags FDFlags) error { } // Update the flags. - f.set(fd, file, flags) + f.set(ctx, fd, file, flags) return nil } // SetFlagsVFS2 sets the flags for the given file descriptor. // // True is returned iff flags were changed. -func (f *FDTable) SetFlagsVFS2(fd int32, flags FDFlags) error { +func (f *FDTable) SetFlagsVFS2(ctx context.Context, fd int32, flags FDFlags) error { if fd < 0 { // Don't accept negative FDs. return syscall.EBADF @@ -485,7 +484,7 @@ func (f *FDTable) SetFlagsVFS2(fd int32, flags FDFlags) error { } // Update the flags. - f.setVFS2(fd, file, flags) + f.setVFS2(ctx, fd, file, flags) return nil } @@ -584,9 +583,9 @@ func (f *FDTable) Fork(ctx context.Context) *FDTable { // reference for the clone. We don't need anything else. switch { case file != nil: - clone.set(fd, file, flags) + clone.set(ctx, fd, file, flags) case fileVFS2 != nil: - clone.setVFS2(fd, fileVFS2, flags) + clone.setVFS2(ctx, fd, fileVFS2, flags) } }) return clone @@ -595,7 +594,7 @@ func (f *FDTable) Fork(ctx context.Context) *FDTable { // Remove removes an FD from and returns a non-file iff successful. // // N.B. Callers are required to use DecRef when they are done. -func (f *FDTable) Remove(fd int32) (*fs.File, *vfs.FileDescription) { +func (f *FDTable) Remove(ctx context.Context, fd int32) (*fs.File, *vfs.FileDescription) { if fd < 0 { return nil, nil } @@ -618,7 +617,7 @@ func (f *FDTable) Remove(fd int32) (*fs.File, *vfs.FileDescription) { orig2.IncRef() } if orig != nil || orig2 != nil { - f.setAll(fd, nil, nil, FDFlags{}) // Zap entry. + f.setAll(ctx, fd, nil, nil, FDFlags{}) // Zap entry. } return orig, orig2 } @@ -630,7 +629,7 @@ func (f *FDTable) RemoveIf(ctx context.Context, cond func(*fs.File, *vfs.FileDes f.forEach(ctx, func(fd int32, file *fs.File, fileVFS2 *vfs.FileDescription, flags FDFlags) { if cond(file, fileVFS2, flags) { - f.set(fd, nil, FDFlags{}) // Clear from table. + f.set(ctx, fd, nil, FDFlags{}) // Clear from table. // Update current available position. if fd < f.next { f.next = fd diff --git a/pkg/sentry/kernel/fd_table_test.go b/pkg/sentry/kernel/fd_table_test.go index e3f30ba2a..bf5460083 100644 --- a/pkg/sentry/kernel/fd_table_test.go +++ b/pkg/sentry/kernel/fd_table_test.go @@ -72,7 +72,7 @@ func TestFDTableMany(t *testing.T) { } i := int32(2) - fdTable.Remove(i) + fdTable.Remove(ctx, i) if fds, err := fdTable.NewFDs(ctx, 0, []*fs.File{file}, FDFlags{}); err != nil || fds[0] != i { t.Fatalf("Allocated %v FDs but wanted to allocate %v: %v", i, maxFD, err) } @@ -93,7 +93,7 @@ func TestFDTableOverLimit(t *testing.T) { t.Fatalf("fdTable.NewFDs(maxFD-3, {f,f,f}): got %v, wanted nil", err) } else { for _, fd := range fds { - fdTable.Remove(fd) + fdTable.Remove(ctx, fd) } } @@ -150,13 +150,13 @@ func TestFDTable(t *testing.T) { t.Fatalf("fdTable.Get(2): got a %v, wanted nil", ref) } - ref, _ := fdTable.Remove(1) + ref, _ := fdTable.Remove(ctx, 1) if ref == nil { t.Fatalf("fdTable.Remove(1) for an existing FD: failed, want success") } ref.DecRef(ctx) - if ref, _ := fdTable.Remove(1); ref != nil { + if ref, _ := fdTable.Remove(ctx, 1); ref != nil { t.Fatalf("r.Remove(1) for a removed FD: got success, want failure") } }) diff --git a/pkg/sentry/kernel/fd_table_unsafe.go b/pkg/sentry/kernel/fd_table_unsafe.go index 6b8feb107..555b14f8e 100644 --- a/pkg/sentry/kernel/fd_table_unsafe.go +++ b/pkg/sentry/kernel/fd_table_unsafe.go @@ -18,6 +18,7 @@ import ( "sync/atomic" "unsafe" + "gvisor.dev/gvisor/pkg/context" "gvisor.dev/gvisor/pkg/sentry/fs" "gvisor.dev/gvisor/pkg/sentry/vfs" ) @@ -84,8 +85,8 @@ func (f *FDTable) getAll(fd int32) (*fs.File, *vfs.FileDescription, FDFlags, boo // reference needed by the table iff the file is different. // // Precondition: mu must be held. -func (f *FDTable) set(fd int32, file *fs.File, flags FDFlags) { - f.setAll(fd, file, nil, flags) +func (f *FDTable) set(ctx context.Context, fd int32, file *fs.File, flags FDFlags) { + f.setAll(ctx, fd, file, nil, flags) } // setVFS2 sets an entry. @@ -94,8 +95,8 @@ func (f *FDTable) set(fd int32, file *fs.File, flags FDFlags) { // reference needed by the table iff the file is different. // // Precondition: mu must be held. -func (f *FDTable) setVFS2(fd int32, file *vfs.FileDescription, flags FDFlags) { - f.setAll(fd, nil, file, flags) +func (f *FDTable) setVFS2(ctx context.Context, fd int32, file *vfs.FileDescription, flags FDFlags) { + f.setAll(ctx, fd, nil, file, flags) } // setAll sets an entry. @@ -104,7 +105,7 @@ func (f *FDTable) setVFS2(fd int32, file *vfs.FileDescription, flags FDFlags) { // reference needed by the table iff the file is different. // // Precondition: mu must be held. -func (f *FDTable) setAll(fd int32, file *fs.File, fileVFS2 *vfs.FileDescription, flags FDFlags) { +func (f *FDTable) setAll(ctx context.Context, fd int32, file *fs.File, fileVFS2 *vfs.FileDescription, flags FDFlags) { if file != nil && fileVFS2 != nil { panic("VFS1 and VFS2 files set") } @@ -152,11 +153,11 @@ func (f *FDTable) setAll(fd int32, file *fs.File, fileVFS2 *vfs.FileDescription, switch { case orig.file != nil: if desc == nil || desc.file != orig.file { - f.drop(orig.file) + f.drop(ctx, orig.file) } case orig.fileVFS2 != nil: if desc == nil || desc.fileVFS2 != orig.fileVFS2 { - f.dropVFS2(orig.fileVFS2) + f.dropVFS2(ctx, orig.fileVFS2) } } } diff --git a/pkg/sentry/syscalls/linux/sys_file.go b/pkg/sentry/syscalls/linux/sys_file.go index 256422689..07c77e442 100644 --- a/pkg/sentry/syscalls/linux/sys_file.go +++ b/pkg/sentry/syscalls/linux/sys_file.go @@ -601,12 +601,12 @@ func Ioctl(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall // Shared flags between file and socket. switch request { case linux.FIONCLEX: - t.FDTable().SetFlags(fd, kernel.FDFlags{ + t.FDTable().SetFlags(t, fd, kernel.FDFlags{ CloseOnExec: false, }) return 0, nil, nil case linux.FIOCLEX: - t.FDTable().SetFlags(fd, kernel.FDFlags{ + t.FDTable().SetFlags(t, fd, kernel.FDFlags{ CloseOnExec: true, }) return 0, nil, nil @@ -787,7 +787,7 @@ func Close(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall // Note that Remove provides a reference on the file that we may use to // flush. It is still active until we drop the final reference below // (and other reference-holding operations complete). - file, _ := t.FDTable().Remove(fd) + file, _ := t.FDTable().Remove(t, fd) if file == nil { return 0, nil, syserror.EBADF } @@ -941,7 +941,7 @@ func Fcntl(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall return uintptr(flags.ToLinuxFDFlags()), nil, nil case linux.F_SETFD: flags := args[2].Uint() - err := t.FDTable().SetFlags(fd, kernel.FDFlags{ + err := t.FDTable().SetFlags(t, fd, kernel.FDFlags{ CloseOnExec: flags&linux.FD_CLOEXEC != 0, }) return 0, nil, err @@ -1154,6 +1154,10 @@ func Fadvise64(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sys return 0, nil, nil } +// LINT.ThenChange(vfs2/fd.go) + +// LINT.IfChange + func mkdirAt(t *kernel.Task, dirFD int32, addr usermem.Addr, mode linux.FileMode) error { path, _, err := copyInPath(t, addr, false /* allowEmpty */) if err != nil { diff --git a/pkg/sentry/syscalls/linux/sys_pipe.go b/pkg/sentry/syscalls/linux/sys_pipe.go index 3149e4aad..c55beb39b 100644 --- a/pkg/sentry/syscalls/linux/sys_pipe.go +++ b/pkg/sentry/syscalls/linux/sys_pipe.go @@ -48,7 +48,7 @@ func pipe2(t *kernel.Task, addr usermem.Addr, flags uint) (uintptr, error) { if _, err := t.CopyOut(addr, fds); err != nil { for _, fd := range fds { - if file, _ := t.FDTable().Remove(fd); file != nil { + if file, _ := t.FDTable().Remove(t, fd); file != nil { file.DecRef(t) } } diff --git a/pkg/sentry/syscalls/linux/sys_socket.go b/pkg/sentry/syscalls/linux/sys_socket.go index 38f573c14..e4528d095 100644 --- a/pkg/sentry/syscalls/linux/sys_socket.go +++ b/pkg/sentry/syscalls/linux/sys_socket.go @@ -249,7 +249,7 @@ func SocketPair(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sy // Copy the file descriptors out. if _, err := t.CopyOut(socks, fds); err != nil { for _, fd := range fds { - if file, _ := t.FDTable().Remove(fd); file != nil { + if file, _ := t.FDTable().Remove(t, fd); file != nil { file.DecRef(t) } } diff --git a/pkg/sentry/syscalls/linux/vfs2/fd.go b/pkg/sentry/syscalls/linux/vfs2/fd.go index 4856554fe..fdd8f88c5 100644 --- a/pkg/sentry/syscalls/linux/vfs2/fd.go +++ b/pkg/sentry/syscalls/linux/vfs2/fd.go @@ -34,7 +34,7 @@ func Close(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall // Note that Remove provides a reference on the file that we may use to // flush. It is still active until we drop the final reference below // (and other reference-holding operations complete). - _, file := t.FDTable().Remove(fd) + _, file := t.FDTable().Remove(t, fd) if file == nil { return 0, nil, syserror.EBADF } @@ -137,7 +137,7 @@ func Fcntl(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall return uintptr(flags.ToLinuxFDFlags()), nil, nil case linux.F_SETFD: flags := args[2].Uint() - err := t.FDTable().SetFlagsVFS2(fd, kernel.FDFlags{ + err := t.FDTable().SetFlagsVFS2(t, fd, kernel.FDFlags{ CloseOnExec: flags&linux.FD_CLOEXEC != 0, }) return 0, nil, err diff --git a/pkg/sentry/syscalls/linux/vfs2/ioctl.go b/pkg/sentry/syscalls/linux/vfs2/ioctl.go index 38778a388..baa8a49af 100644 --- a/pkg/sentry/syscalls/linux/vfs2/ioctl.go +++ b/pkg/sentry/syscalls/linux/vfs2/ioctl.go @@ -34,13 +34,13 @@ func Ioctl(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall // Handle ioctls that apply to all FDs. switch args[1].Int() { case linux.FIONCLEX: - t.FDTable().SetFlagsVFS2(fd, kernel.FDFlags{ + t.FDTable().SetFlagsVFS2(t, fd, kernel.FDFlags{ CloseOnExec: false, }) return 0, nil, nil case linux.FIOCLEX: - t.FDTable().SetFlagsVFS2(fd, kernel.FDFlags{ + t.FDTable().SetFlagsVFS2(t, fd, kernel.FDFlags{ CloseOnExec: true, }) return 0, nil, nil diff --git a/pkg/sentry/syscalls/linux/vfs2/pipe.go b/pkg/sentry/syscalls/linux/vfs2/pipe.go index 9b4848d9e..3aa6d939d 100644 --- a/pkg/sentry/syscalls/linux/vfs2/pipe.go +++ b/pkg/sentry/syscalls/linux/vfs2/pipe.go @@ -53,7 +53,7 @@ func pipe2(t *kernel.Task, addr usermem.Addr, flags int32) error { } if _, err := t.CopyOut(addr, fds); err != nil { for _, fd := range fds { - if _, file := t.FDTable().Remove(fd); file != nil { + if _, file := t.FDTable().Remove(t, fd); file != nil { file.DecRef(t) } } diff --git a/pkg/sentry/syscalls/linux/vfs2/socket.go b/pkg/sentry/syscalls/linux/vfs2/socket.go index a5032657a..a15dad29f 100644 --- a/pkg/sentry/syscalls/linux/vfs2/socket.go +++ b/pkg/sentry/syscalls/linux/vfs2/socket.go @@ -252,7 +252,7 @@ func SocketPair(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sy if _, err := t.CopyOut(addr, fds); err != nil { for _, fd := range fds { - if _, file := t.FDTable().Remove(fd); file != nil { + if _, file := t.FDTable().Remove(t, fd); file != nil { file.DecRef(t) } } -- cgit v1.2.3