Merge release-20200518.0-45-g0bc022b7 (automated)

14 files changed, 50 insertions, 80 deletions

diff --git a/pkg/sentry/fsimpl/gofer/dentry_list.go b/pkg/sentry/fsimpl/gofer/dentry_list.go
index fa03e2501..fa03e2501 100755..100644
--- a/pkg/sentry/fsimpl/gofer/dentry_list.go
+++ b/pkg/sentry/fsimpl/gofer/dentry_list.go
diff --git a/pkg/sentry/fsimpl/gofer/directory.go b/pkg/sentry/fsimpl/gofer/directory.go
index b98218753..b98218753 100755..100644
--- a/pkg/sentry/fsimpl/gofer/directory.go
+++ b/pkg/sentry/fsimpl/gofer/directory.go
diff --git a/pkg/sentry/fsimpl/gofer/filesystem.go b/pkg/sentry/fsimpl/gofer/filesystem.go
index 7f2181216..7f2181216 100755..100644
--- a/pkg/sentry/fsimpl/gofer/filesystem.go
+++ b/pkg/sentry/fsimpl/gofer/filesystem.go
diff --git a/pkg/sentry/fsimpl/gofer/fstree.go b/pkg/sentry/fsimpl/gofer/fstree.go
index 9ef0dd8c8..9ef0dd8c8 100755..100644
--- a/pkg/sentry/fsimpl/gofer/fstree.go
+++ b/pkg/sentry/fsimpl/gofer/fstree.go
diff --git a/pkg/sentry/fsimpl/gofer/gofer.go b/pkg/sentry/fsimpl/gofer/gofer.go
index ebf063a58..131da332f 100755..100644
--- a/pkg/sentry/fsimpl/gofer/gofer.go
+++ b/pkg/sentry/fsimpl/gofer/gofer.go
@@ -84,12 +84,6 @@ type filesystem struct {
 	// devMinor is the filesystem's minor device number. devMinor is immutable.
 	devMinor uint32
 
-	// uid and gid are the effective KUID and KGID of the filesystem's creator,
-	// and are used as the owner and group for files that don't specify one.
-	// uid and gid are immutable.
-	uid auth.KUID
-	gid auth.KGID
-
 	// renameMu serves two purposes:
 	//
 	// - It synchronizes path resolution with renaming initiated by this
@@ -122,6 +116,8 @@ type filesystemOptions struct {
 	fd      int
 	aname   string
 	interop InteropMode // derived from the "cache" mount option
+	dfltuid auth.KUID
+	dfltgid auth.KGID
 	msize   uint32
 	version string
 
@@ -230,6 +226,15 @@ type InternalFilesystemOptions struct {
 	OpenSocketsByConnecting bool
 }
 
+// _V9FS_DEFUID and _V9FS_DEFGID (from Linux's fs/9p/v9fs.h) are the default
+// UIDs and GIDs used for files that do not provide a specific owner or group
+// respectively.
+const (
+	// uint32(-2) doesn't work in Go.
+	_V9FS_DEFUID = auth.KUID(4294967294)
+	_V9FS_DEFGID = auth.KGID(4294967294)
+)
+
 // Name implements vfs.FilesystemType.Name.
 func (FilesystemType) Name() string {
 	return Name
@@ -315,6 +320,31 @@ func (fstype FilesystemType) GetFilesystem(ctx context.Context, vfsObj *vfs.Virt
 		}
 	}
 
+	// Parse the default UID and GID.
+	fsopts.dfltuid = _V9FS_DEFUID
+	if dfltuidstr, ok := mopts["dfltuid"]; ok {
+		delete(mopts, "dfltuid")
+		dfltuid, err := strconv.ParseUint(dfltuidstr, 10, 32)
+		if err != nil {
+			ctx.Warningf("gofer.FilesystemType.GetFilesystem: invalid default UID: dfltuid=%s", dfltuidstr)
+			return nil, nil, syserror.EINVAL
+		}
+		// In Linux, dfltuid is interpreted as a UID and is converted to a KUID
+		// in the caller's user namespace, but goferfs isn't
+		// application-mountable.
+		fsopts.dfltuid = auth.KUID(dfltuid)
+	}
+	fsopts.dfltgid = _V9FS_DEFGID
+	if dfltgidstr, ok := mopts["dfltgid"]; ok {
+		delete(mopts, "dfltgid")
+		dfltgid, err := strconv.ParseUint(dfltgidstr, 10, 32)
+		if err != nil {
+			ctx.Warningf("gofer.FilesystemType.GetFilesystem: invalid default UID: dfltgid=%s", dfltgidstr)
+			return nil, nil, syserror.EINVAL
+		}
+		fsopts.dfltgid = auth.KGID(dfltgid)
+	}
+
 	// Parse the 9P message size.
 	fsopts.msize = 1024 * 1024 // 1M, tested to give good enough performance up to 64M
 	if msizestr, ok := mopts["msize"]; ok {
@@ -422,8 +452,6 @@ func (fstype FilesystemType) GetFilesystem(ctx context.Context, vfsObj *vfs.Virt
 		client:           client,
 		clock:            ktime.RealtimeClockFromContext(ctx),
 		devMinor:         devMinor,
-		uid:              creds.EffectiveKUID,
-		gid:              creds.EffectiveKGID,
 		syncableDentries: make(map[*dentry]struct{}),
 		specialFileFDs:   make(map[*specialFileFD]struct{}),
 	}
@@ -672,8 +700,8 @@ func (fs *filesystem) newDentry(ctx context.Context, file p9file, qid p9.QID, ma
 		file:      file,
 		ino:       qid.Path,
 		mode:      uint32(attr.Mode),
-		uid:       uint32(fs.uid),
-		gid:       uint32(fs.gid),
+		uid:       uint32(fs.opts.dfltuid),
+		gid:       uint32(fs.opts.dfltgid),
 		blockSize: usermem.PageSize,
 		handle: handle{
 			fd: -1,
@@ -928,8 +956,8 @@ func (d *dentry) setStat(ctx context.Context, creds *auth.Credentials, stat *lin
 		// so we can't race with Write or another truncate.)
 		d.dataMu.Unlock()
 		if d.size < oldSize {
-			oldpgend := pageRoundUp(oldSize)
-			newpgend := pageRoundUp(d.size)
+			oldpgend, _ := usermem.PageRoundUp(oldSize)
+			newpgend, _ := usermem.PageRoundUp(d.size)
 			if oldpgend != newpgend {
 				d.mapsMu.Lock()
 				d.mappings.Invalidate(memmap.MappableRange{newpgend, oldpgend}, memmap.InvalidateOpts{
diff --git a/pkg/sentry/fsimpl/gofer/gofer_state_autogen.go b/pkg/sentry/fsimpl/gofer/gofer_state_autogen.go
index 546d432c9..546d432c9 100755..100644
--- a/pkg/sentry/fsimpl/gofer/gofer_state_autogen.go
+++ b/pkg/sentry/fsimpl/gofer/gofer_state_autogen.go
diff --git a/pkg/sentry/fsimpl/gofer/handle.go b/pkg/sentry/fsimpl/gofer/handle.go
index 724a3f1f7..724a3f1f7 100755..100644
--- a/pkg/sentry/fsimpl/gofer/handle.go
+++ b/pkg/sentry/fsimpl/gofer/handle.go
diff --git a/pkg/sentry/fsimpl/gofer/p9file.go b/pkg/sentry/fsimpl/gofer/p9file.go
index 87f0b877f..87f0b877f 100755..100644
--- a/pkg/sentry/fsimpl/gofer/p9file.go
+++ b/pkg/sentry/fsimpl/gofer/p9file.go
diff --git a/pkg/sentry/fsimpl/gofer/pagemath.go b/pkg/sentry/fsimpl/gofer/pagemath.go
deleted file mode 100755
index 847cb0784..000000000
--- a/pkg/sentry/fsimpl/gofer/pagemath.go
+++ /dev/null
@@ -1,31 +0,0 @@
-// Copyright 2019 The gVisor Authors.
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package gofer
-
-import (
-	"gvisor.dev/gvisor/pkg/usermem"
-)
-
-// This are equivalent to usermem.Addr.RoundDown/Up, but without the
-// potentially truncating conversion to usermem.Addr. This is necessary because
-// there is no way to define generic "PageRoundDown/Up" functions in Go.
-
-func pageRoundDown(x uint64) uint64 {
-	return x &^ (usermem.PageSize - 1)
-}
-
-func pageRoundUp(x uint64) uint64 {
-	return pageRoundDown(x + usermem.PageSize - 1)
-}
diff --git a/pkg/sentry/fsimpl/gofer/regular_file.go b/pkg/sentry/fsimpl/gofer/regular_file.go
index 857f7c74e..0d10cf7ac 100755..100644
--- a/pkg/sentry/fsimpl/gofer/regular_file.go
+++ b/pkg/sentry/fsimpl/gofer/regular_file.go
@@ -148,9 +148,9 @@ func (fd *regularFileFD) PWrite(ctx context.Context, src usermem.IOSequence, off
 			return 0, err
 		}
 		// Remove touched pages from the cache.
-		pgstart := pageRoundDown(uint64(offset))
-		pgend := pageRoundUp(uint64(offset + src.NumBytes()))
-		if pgend < pgstart {
+		pgstart := usermem.PageRoundDown(uint64(offset))
+		pgend, ok := usermem.PageRoundUp(uint64(offset + src.NumBytes()))
+		if !ok {
 			return 0, syserror.EINVAL
 		}
 		mr := memmap.MappableRange{pgstart, pgend}
@@ -306,9 +306,10 @@ func (rw *dentryReadWriter) ReadToBlocks(dsts safemem.BlockSeq) (uint64, error)
 			if fillCache {
 				// Read into the cache, then re-enter the loop to read from the
 				// cache.
+				gapEnd, _ := usermem.PageRoundUp(gapMR.End)
 				reqMR := memmap.MappableRange{
-					Start: pageRoundDown(gapMR.Start),
-					End:   pageRoundUp(gapMR.End),
+					Start: usermem.PageRoundDown(gapMR.Start),
+					End:   gapEnd,
 				}
 				optMR := gap.Range()
 				err := rw.d.cache.Fill(rw.ctx, reqMR, maxFillRange(reqMR, optMR), mf, usage.PageCache, rw.d.handle.readToBlocksAt)
@@ -671,7 +672,7 @@ func (d *dentry) Translate(ctx context.Context, required, optional memmap.Mappab
 
 	// Constrain translations to d.size (rounded up) to prevent translation to
 	// pages that may be concurrently truncated.
-	pgend := pageRoundUp(d.size)
+	pgend, _ := usermem.PageRoundUp(d.size)
 	var beyondEOF bool
 	if required.End > pgend {
 		if required.Start >= pgend {
@@ -818,43 +819,15 @@ type dentryPlatformFile struct {
 // IncRef implements platform.File.IncRef.
 func (d *dentryPlatformFile) IncRef(fr platform.FileRange) {
 	d.dataMu.Lock()
-	seg, gap := d.fdRefs.Find(fr.Start)
-	for {
-		switch {
-		case seg.Ok() && seg.Start() < fr.End:
-			seg = d.fdRefs.Isolate(seg, fr)
-			seg.SetValue(seg.Value() + 1)
-			seg, gap = seg.NextNonEmpty()
-		case gap.Ok() && gap.Start() < fr.End:
-			newRange := gap.Range().Intersect(fr)
-			usage.MemoryAccounting.Inc(newRange.Length(), usage.Mapped)
-			seg, gap = d.fdRefs.InsertWithoutMerging(gap, newRange, 1).NextNonEmpty()
-		default:
-			d.fdRefs.MergeAdjacent(fr)
-			d.dataMu.Unlock()
-			return
-		}
-	}
+	d.fdRefs.IncRefAndAccount(fr)
+	d.dataMu.Unlock()
 }
 
 // DecRef implements platform.File.DecRef.
 func (d *dentryPlatformFile) DecRef(fr platform.FileRange) {
 	d.dataMu.Lock()
-	seg := d.fdRefs.FindSegment(fr.Start)
-
-	for seg.Ok() && seg.Start() < fr.End {
-		seg = d.fdRefs.Isolate(seg, fr)
-		if old := seg.Value(); old == 1 {
-			usage.MemoryAccounting.Dec(seg.Range().Length(), usage.Mapped)
-			seg = d.fdRefs.Remove(seg).NextSegment()
-		} else {
-			seg.SetValue(old - 1)
-			seg = seg.NextSegment()
-		}
-	}
-	d.fdRefs.MergeAdjacent(fr)
+	d.fdRefs.DecRefAndAccount(fr)
 	d.dataMu.Unlock()
-
 }
 
 // MapInternal implements platform.File.MapInternal.
diff --git a/pkg/sentry/fsimpl/gofer/socket.go b/pkg/sentry/fsimpl/gofer/socket.go
index d6dbe9092..d6dbe9092 100755..100644
--- a/pkg/sentry/fsimpl/gofer/socket.go
+++ b/pkg/sentry/fsimpl/gofer/socket.go
diff --git a/pkg/sentry/fsimpl/gofer/special_file.go b/pkg/sentry/fsimpl/gofer/special_file.go
index a464e6a94..a464e6a94 100755..100644
--- a/pkg/sentry/fsimpl/gofer/special_file.go
+++ b/pkg/sentry/fsimpl/gofer/special_file.go
diff --git a/pkg/sentry/fsimpl/gofer/symlink.go b/pkg/sentry/fsimpl/gofer/symlink.go
index 2ec819f86..2ec819f86 100755..100644
--- a/pkg/sentry/fsimpl/gofer/symlink.go
+++ b/pkg/sentry/fsimpl/gofer/symlink.go
diff --git a/pkg/sentry/fsimpl/gofer/time.go b/pkg/sentry/fsimpl/gofer/time.go
index 2608e7e1d..2608e7e1d 100755..100644
--- a/pkg/sentry/fsimpl/gofer/time.go
+++ b/pkg/sentry/fsimpl/gofer/time.go