Merge release-20210906.0-35-g51b96514c (automated)

3 files changed, 30 insertions, 7 deletions

diff --git a/pkg/sentry/fs/file_overlay.go b/pkg/sentry/fs/file_overlay.go
index 031cd33ce..a27dd0b9a 100644
--- a/pkg/sentry/fs/file_overlay.go
+++ b/pkg/sentry/fs/file_overlay.go
@@ -16,6 +16,7 @@ package fs
 
 import (
 	"io"
+	"math"
 
 	"gvisor.dev/gvisor/pkg/context"
 	"gvisor.dev/gvisor/pkg/errors/linuxerr"
@@ -360,10 +361,13 @@ func (*overlayFileOperations) ConfigureMMap(ctx context.Context, file *File, opt
 		return linuxerr.ENODEV
 	}
 
-	// FIXME(jamieliu): This is a copy/paste of fsutil.GenericConfigureMMap,
-	// which we can't use because the overlay implementation is in package fs,
-	// so depending on fs/fsutil would create a circular dependency. Move
-	// overlay to fs/overlay.
+	// TODO(gvisor.dev/issue/1624): This is a copy/paste of
+	// fsutil.GenericConfigureMMap, which we can't use because the overlay
+	// implementation is in package fs, so depending on fs/fsutil would create
+	// a circular dependency. VFS2 overlay doesn't have this issue.
+	if opts.Offset+opts.Length > math.MaxInt64 {
+		return linuxerr.EOVERFLOW
+	}
 	opts.Mappable = o
 	opts.MappingIdentity = file
 	file.IncRef()
diff --git a/pkg/sentry/fs/fsutil/file.go b/pkg/sentry/fs/fsutil/file.go
index 3ece73b81..38e3ed42d 100644
--- a/pkg/sentry/fs/fsutil/file.go
+++ b/pkg/sentry/fs/fsutil/file.go
@@ -16,6 +16,7 @@ package fsutil
 
 import (
 	"io"
+	"math"
 
 	"gvisor.dev/gvisor/pkg/context"
 	"gvisor.dev/gvisor/pkg/errors/linuxerr"
@@ -210,6 +211,9 @@ func (FileNoMMap) ConfigureMMap(context.Context, *fs.File, *memmap.MMapOpts) err
 // GenericConfigureMMap implements fs.FileOperations.ConfigureMMap for most
 // filesystems that support memory mapping.
 func GenericConfigureMMap(file *fs.File, m memmap.Mappable, opts *memmap.MMapOpts) error {
+	if opts.Offset+opts.Length > math.MaxInt64 {
+		return linuxerr.EOVERFLOW
+	}
 	opts.Mappable = m
 	opts.MappingIdentity = file
 	file.IncRef()
diff --git a/pkg/sentry/fs/fsutil/host_file_mapper.go b/pkg/sentry/fs/fsutil/host_file_mapper.go
index 23528bf25..37ddb1a3c 100644
--- a/pkg/sentry/fs/fsutil/host_file_mapper.go
+++ b/pkg/sentry/fs/fsutil/host_file_mapper.go
@@ -93,7 +93,8 @@ func NewHostFileMapper() *HostFileMapper {
 func (f *HostFileMapper) IncRefOn(mr memmap.MappableRange) {
 	f.refsMu.Lock()
 	defer f.refsMu.Unlock()
-	for chunkStart := mr.Start &^ chunkMask; chunkStart < mr.End; chunkStart += chunkSize {
+	chunkStart := mr.Start &^ chunkMask
+	for {
 		refs := f.refs[chunkStart]
 		pgs := pagesInChunk(mr, chunkStart)
 		if refs+pgs < refs {
@@ -101,6 +102,10 @@ func (f *HostFileMapper) IncRefOn(mr memmap.MappableRange) {
 			panic(fmt.Sprintf("HostFileMapper.IncRefOn(%v): adding %d page references to chunk %#x, which has %d page references", mr, pgs, chunkStart, refs))
 		}
 		f.refs[chunkStart] = refs + pgs
+		chunkStart += chunkSize
+		if chunkStart >= mr.End || chunkStart == 0 {
+			break
+		}
 	}
 }
 
@@ -112,7 +117,8 @@ func (f *HostFileMapper) IncRefOn(mr memmap.MappableRange) {
 func (f *HostFileMapper) DecRefOn(mr memmap.MappableRange) {
 	f.refsMu.Lock()
 	defer f.refsMu.Unlock()
-	for chunkStart := mr.Start &^ chunkMask; chunkStart < mr.End; chunkStart += chunkSize {
+	chunkStart := mr.Start &^ chunkMask
+	for {
 		refs := f.refs[chunkStart]
 		pgs := pagesInChunk(mr, chunkStart)
 		switch {
@@ -128,6 +134,10 @@ func (f *HostFileMapper) DecRefOn(mr memmap.MappableRange) {
 		case refs < pgs:
 			panic(fmt.Sprintf("HostFileMapper.DecRefOn(%v): removing %d page references from chunk %#x, which has %d page references", mr, pgs, chunkStart, refs))
 		}
+		chunkStart += chunkSize
+		if chunkStart >= mr.End || chunkStart == 0 {
+			break
+		}
 	}
 }
 
@@ -161,7 +171,8 @@ func (f *HostFileMapper) forEachMappingBlockLocked(fr memmap.FileRange, fd int,
 	if write {
 		prot |= unix.PROT_WRITE
 	}
-	for chunkStart := fr.Start &^ chunkMask; chunkStart < fr.End; chunkStart += chunkSize {
+	chunkStart := fr.Start &^ chunkMask
+	for {
 		m, ok := f.mappings[chunkStart]
 		if !ok {
 			addr, _, errno := unix.Syscall6(
@@ -201,6 +212,10 @@ func (f *HostFileMapper) forEachMappingBlockLocked(fr memmap.FileRange, fd int,
 			endOff = fr.End - chunkStart
 		}
 		fn(f.unsafeBlockFromChunkMapping(m.addr).TakeFirst64(endOff).DropFirst64(startOff))
+		chunkStart += chunkSize
+		if chunkStart >= fr.End || chunkStart == 0 {
+			break
+		}
 	}
 	return nil
 }