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-rw-r--r--pkg/sentry/devices/memdev/zero.go1
-rw-r--r--pkg/sentry/fsimpl/gofer/regular_file.go1
-rw-r--r--pkg/sentry/fsimpl/tmpfs/regular_file.go1
-rw-r--r--pkg/sentry/fsimpl/verity/BUILD2
-rw-r--r--pkg/sentry/fsimpl/verity/verity.go137
-rw-r--r--pkg/sentry/memmap/memmap.go5
6 files changed, 145 insertions, 2 deletions
diff --git a/pkg/sentry/devices/memdev/zero.go b/pkg/sentry/devices/memdev/zero.go
index 1929e41cd..49c53452a 100644
--- a/pkg/sentry/devices/memdev/zero.go
+++ b/pkg/sentry/devices/memdev/zero.go
@@ -93,6 +93,7 @@ func (fd *zeroFD) ConfigureMMap(ctx context.Context, opts *memmap.MMapOpts) erro
// "/dev/zero (deleted)".
opts.Offset = 0
opts.MappingIdentity = &fd.vfsfd
+ opts.SentryOwnedContent = true
opts.MappingIdentity.IncRef()
return nil
}
diff --git a/pkg/sentry/fsimpl/gofer/regular_file.go b/pkg/sentry/fsimpl/gofer/regular_file.go
index 47563538c..713f0a480 100644
--- a/pkg/sentry/fsimpl/gofer/regular_file.go
+++ b/pkg/sentry/fsimpl/gofer/regular_file.go
@@ -701,6 +701,7 @@ func (fd *regularFileFD) ConfigureMMap(ctx context.Context, opts *memmap.MMapOpt
}
// After this point, d may be used as a memmap.Mappable.
d.pf.hostFileMapperInitOnce.Do(d.pf.hostFileMapper.Init)
+ opts.SentryOwnedContent = d.fs.opts.forcePageCache
return vfs.GenericConfigureMMap(&fd.vfsfd, d, opts)
}
diff --git a/pkg/sentry/fsimpl/tmpfs/regular_file.go b/pkg/sentry/fsimpl/tmpfs/regular_file.go
index cd849e87e..c45bddff6 100644
--- a/pkg/sentry/fsimpl/tmpfs/regular_file.go
+++ b/pkg/sentry/fsimpl/tmpfs/regular_file.go
@@ -488,6 +488,7 @@ func (fd *regularFileFD) Seek(ctx context.Context, offset int64, whence int32) (
// ConfigureMMap implements vfs.FileDescriptionImpl.ConfigureMMap.
func (fd *regularFileFD) ConfigureMMap(ctx context.Context, opts *memmap.MMapOpts) error {
file := fd.inode().impl.(*regularFile)
+ opts.SentryOwnedContent = true
return vfs.GenericConfigureMMap(&fd.vfsfd, file, opts)
}
diff --git a/pkg/sentry/fsimpl/verity/BUILD b/pkg/sentry/fsimpl/verity/BUILD
index 2da251233..d473a922d 100644
--- a/pkg/sentry/fsimpl/verity/BUILD
+++ b/pkg/sentry/fsimpl/verity/BUILD
@@ -18,10 +18,12 @@ go_library(
"//pkg/marshal/primitive",
"//pkg/merkletree",
"//pkg/refsvfs2",
+ "//pkg/safemem",
"//pkg/sentry/arch",
"//pkg/sentry/fs/lock",
"//pkg/sentry/kernel",
"//pkg/sentry/kernel/auth",
+ "//pkg/sentry/memmap",
"//pkg/sentry/socket/unix/transport",
"//pkg/sentry/vfs",
"//pkg/sync",
diff --git a/pkg/sentry/fsimpl/verity/verity.go b/pkg/sentry/fsimpl/verity/verity.go
index a7d92a878..2f97324a8 100644
--- a/pkg/sentry/fsimpl/verity/verity.go
+++ b/pkg/sentry/fsimpl/verity/verity.go
@@ -34,6 +34,7 @@
package verity
import (
+ "bytes"
"encoding/json"
"fmt"
"math"
@@ -44,19 +45,20 @@ import (
"gvisor.dev/gvisor/pkg/abi/linux"
"gvisor.dev/gvisor/pkg/context"
"gvisor.dev/gvisor/pkg/fspath"
+ "gvisor.dev/gvisor/pkg/hostarch"
"gvisor.dev/gvisor/pkg/marshal/primitive"
"gvisor.dev/gvisor/pkg/merkletree"
"gvisor.dev/gvisor/pkg/refsvfs2"
+ "gvisor.dev/gvisor/pkg/safemem"
"gvisor.dev/gvisor/pkg/sentry/arch"
fslock "gvisor.dev/gvisor/pkg/sentry/fs/lock"
"gvisor.dev/gvisor/pkg/sentry/kernel"
"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
+ "gvisor.dev/gvisor/pkg/sentry/memmap"
"gvisor.dev/gvisor/pkg/sentry/vfs"
"gvisor.dev/gvisor/pkg/sync"
"gvisor.dev/gvisor/pkg/syserror"
"gvisor.dev/gvisor/pkg/usermem"
-
- "gvisor.dev/gvisor/pkg/hostarch"
)
const (
@@ -722,6 +724,10 @@ type fileDescription struct {
// underlying file system.
lowerFD *vfs.FileDescription
+ // lowerMappable is the memmap.Mappable corresponding to this file in the
+ // underlying file system.
+ lowerMappable memmap.Mappable
+
// merkleReader is the read-only FileDescription corresponding to the
// Merkle tree file in the underlying file system.
merkleReader *vfs.FileDescription
@@ -1201,6 +1207,24 @@ func (fd *fileDescription) Write(ctx context.Context, src usermem.IOSequence, op
return 0, syserror.EROFS
}
+// ConfigureMMap implements vfs.FileDescriptionImpl.ConfigureMMap.
+func (fd *fileDescription) ConfigureMMap(ctx context.Context, opts *memmap.MMapOpts) error {
+ if err := fd.lowerFD.ConfigureMMap(ctx, opts); err != nil {
+ return err
+ }
+ fd.lowerMappable = opts.Mappable
+ if opts.MappingIdentity != nil {
+ opts.MappingIdentity.DecRef(ctx)
+ opts.MappingIdentity = nil
+ }
+
+ // Check if mmap is allowed on the lower filesystem.
+ if !opts.SentryOwnedContent {
+ return syserror.ENODEV
+ }
+ return vfs.GenericConfigureMMap(&fd.vfsfd, fd, opts)
+}
+
// LockBSD implements vfs.FileDescriptionImpl.LockBSD.
func (fd *fileDescription) LockBSD(ctx context.Context, uid fslock.UniqueID, ownerPID int32, t fslock.LockType, block fslock.Blocker) error {
return fd.lowerFD.LockBSD(ctx, ownerPID, t, block)
@@ -1226,6 +1250,115 @@ func (fd *fileDescription) TestPOSIX(ctx context.Context, uid fslock.UniqueID, t
return fd.lowerFD.TestPOSIX(ctx, uid, t, r)
}
+// Translate implements memmap.Mappable.Translate.
+func (fd *fileDescription) Translate(ctx context.Context, required, optional memmap.MappableRange, at hostarch.AccessType) ([]memmap.Translation, error) {
+ ts, err := fd.lowerMappable.Translate(ctx, required, optional, at)
+ if err != nil {
+ return ts, err
+ }
+
+ // dataSize is the size of the whole file.
+ dataSize, err := fd.merkleReader.GetXattr(ctx, &vfs.GetXattrOptions{
+ Name: merkleSizeXattr,
+ Size: sizeOfStringInt32,
+ })
+
+ // The Merkle tree file for the child should have been created and
+ // contains the expected xattrs. If the xattr does not exist, it
+ // indicates unexpected modifications to the file system.
+ if err == syserror.ENODATA {
+ return ts, alertIntegrityViolation(fmt.Sprintf("Failed to get xattr %s: %v", merkleSizeXattr, err))
+ }
+ if err != nil {
+ return ts, err
+ }
+
+ // The dataSize xattr should be an integer. If it's not, it indicates
+ // unexpected modifications to the file system.
+ size, err := strconv.Atoi(dataSize)
+ if err != nil {
+ return ts, alertIntegrityViolation(fmt.Sprintf("Failed to convert xattr %s to int: %v", merkleSizeXattr, err))
+ }
+
+ merkleReader := FileReadWriteSeeker{
+ FD: fd.merkleReader,
+ Ctx: ctx,
+ }
+
+ for _, t := range ts {
+ // Content integrity relies on sentry owning the backing data. MapInternal is guaranteed
+ // to fetch sentry owned memory because we disallow verity mmaps otherwise.
+ ims, err := t.File.MapInternal(memmap.FileRange{t.Offset, t.Offset + t.Source.Length()}, hostarch.Read)
+ if err != nil {
+ return nil, err
+ }
+ dataReader := mmapReadSeeker{ims, t.Source.Start}
+ var buf bytes.Buffer
+ _, err = merkletree.Verify(&merkletree.VerifyParams{
+ Out: &buf,
+ File: &dataReader,
+ Tree: &merkleReader,
+ Size: int64(size),
+ Name: fd.d.name,
+ Mode: fd.d.mode,
+ UID: fd.d.uid,
+ GID: fd.d.gid,
+ HashAlgorithms: fd.d.fs.alg.toLinuxHashAlg(),
+ ReadOffset: int64(t.Source.Start),
+ ReadSize: int64(t.Source.Length()),
+ Expected: fd.d.hash,
+ DataAndTreeInSameFile: false,
+ })
+ if err != nil {
+ return ts, alertIntegrityViolation(fmt.Sprintf("Verification failed: %v", err))
+ }
+ }
+ return ts, err
+}
+
+// AddMapping implements memmap.Mappable.AddMapping.
+func (fd *fileDescription) AddMapping(ctx context.Context, ms memmap.MappingSpace, ar hostarch.AddrRange, offset uint64, writable bool) error {
+ return fd.lowerMappable.AddMapping(ctx, ms, ar, offset, writable)
+}
+
+// RemoveMapping implements memmap.Mappable.RemoveMapping.
+func (fd *fileDescription) RemoveMapping(ctx context.Context, ms memmap.MappingSpace, ar hostarch.AddrRange, offset uint64, writable bool) {
+ fd.lowerMappable.RemoveMapping(ctx, ms, ar, offset, writable)
+}
+
+// CopyMapping implements memmap.Mappable.CopyMapping.
+func (fd *fileDescription) CopyMapping(ctx context.Context, ms memmap.MappingSpace, srcAR, dstAR hostarch.AddrRange, offset uint64, writable bool) error {
+ return fd.lowerMappable.CopyMapping(ctx, ms, srcAR, dstAR, offset, writable)
+}
+
+// InvalidateUnsavable implements memmap.Mappable.InvalidateUnsavable.
+func (fd *fileDescription) InvalidateUnsavable(context.Context) error {
+ return nil
+}
+
+// mmapReadSeeker is a helper struct used by fileDescription.Translate to pass
+// a safemem.BlockSeq pointing to the mapped region as io.ReaderAt.
+type mmapReadSeeker struct {
+ safemem.BlockSeq
+ Offset uint64
+}
+
+// ReadAt implements io.ReaderAt.ReadAt. off is the offset into the mapped file.
+func (r *mmapReadSeeker) ReadAt(p []byte, off int64) (int, error) {
+ bs := r.BlockSeq
+ // Adjust the offset into the mapped file to get the offset into the internally
+ // mapped region.
+ readOffset := off - int64(r.Offset)
+ if readOffset < 0 {
+ return 0, syserror.EINVAL
+ }
+ bs.DropFirst64(uint64(readOffset))
+ view := bs.TakeFirst64(uint64(len(p)))
+ dst := safemem.BlockSeqOf(safemem.BlockFromSafeSlice(p))
+ n, err := safemem.CopySeq(dst, view)
+ return int(n), err
+}
+
// FileReadWriteSeeker is a helper struct to pass a vfs.FileDescription as
// io.Reader/io.Writer/io.ReadSeeker/io.ReaderAt/io.WriterAt/etc.
type FileReadWriteSeeker struct {
diff --git a/pkg/sentry/memmap/memmap.go b/pkg/sentry/memmap/memmap.go
index 72868646a..610686ea0 100644
--- a/pkg/sentry/memmap/memmap.go
+++ b/pkg/sentry/memmap/memmap.go
@@ -375,6 +375,11 @@ type MMapOpts struct {
//
// If Force is true, Unmap and Fixed must be true.
Force bool
+
+ // SentryOwnedContent indicates the sentry exclusively controls the
+ // underlying memory backing the mapping thus the memory content is
+ // guaranteed not to be modified outside the sentry's purview.
+ SentryOwnedContent bool
}
// File represents a host file that may be mapped into an platform.AddressSpace.
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-16 09:43:25 +0000