From efa2615eb008a642dc542176759dc560c5f48a2d Mon Sep 17 00:00:00 2001 From: Ayush Ranjan Date: Tue, 7 Jul 2020 21:35:47 -0700 Subject: [vfs2] Remove VFS1 usage in VDSO. Removed VDSO dependency on VFS1. Resolves #2921 PiperOrigin-RevId: 320122176 --- pkg/sentry/fsimpl/testutil/kernel.go | 2 +- pkg/sentry/loader/BUILD | 4 --- pkg/sentry/loader/elf.go | 15 +++++++-- pkg/sentry/loader/loader.go | 17 ---------- pkg/sentry/loader/vdso.go | 61 +++--------------------------------- 5 files changed, 18 insertions(+), 81 deletions(-) (limited to 'pkg') diff --git a/pkg/sentry/fsimpl/testutil/kernel.go b/pkg/sentry/fsimpl/testutil/kernel.go index c16a36cdb..ecc81e6bf 100644 --- a/pkg/sentry/fsimpl/testutil/kernel.go +++ b/pkg/sentry/fsimpl/testutil/kernel.go @@ -73,7 +73,7 @@ func Boot() (*kernel.Kernel, error) { k.SetMemoryFile(mf) // Pass k as the platform since it is savable, unlike the actual platform. - vdso, err := loader.PrepareVDSO(nil, k) + vdso, err := loader.PrepareVDSO(k) if err != nil { return nil, fmt.Errorf("creating vdso: %v", err) } diff --git a/pkg/sentry/loader/BUILD b/pkg/sentry/loader/BUILD index c6aa65f28..34bdb0b69 100644 --- a/pkg/sentry/loader/BUILD +++ b/pkg/sentry/loader/BUILD @@ -30,9 +30,6 @@ go_library( "//pkg/rand", "//pkg/safemem", "//pkg/sentry/arch", - "//pkg/sentry/fs", - "//pkg/sentry/fs/anon", - "//pkg/sentry/fs/fsutil", "//pkg/sentry/fsbridge", "//pkg/sentry/kernel/auth", "//pkg/sentry/limits", @@ -45,6 +42,5 @@ go_library( "//pkg/syserr", "//pkg/syserror", "//pkg/usermem", - "//pkg/waiter", ], ) diff --git a/pkg/sentry/loader/elf.go b/pkg/sentry/loader/elf.go index 616fafa2c..ddeaff3db 100644 --- a/pkg/sentry/loader/elf.go +++ b/pkg/sentry/loader/elf.go @@ -90,14 +90,23 @@ type elfInfo struct { sharedObject bool } +// fullReader interface extracts the ReadFull method from fsbridge.File so that +// client code does not need to define an entire fsbridge.File when only read +// functionality is needed. +// +// TODO(gvisor.dev/issue/1035): Once VFS2 ships, rewrite this to wrap +// vfs.FileDescription's PRead/Read instead. +type fullReader interface { + // ReadFull is the same as fsbridge.File.ReadFull. + ReadFull(ctx context.Context, dst usermem.IOSequence, offset int64) (int64, error) +} + // parseHeader parse the ELF header, verifying that this is a supported ELF // file and returning the ELF program headers. // // This is similar to elf.NewFile, except that it is more strict about what it // accepts from the ELF, and it doesn't parse unnecessary parts of the file. -// -// ctx may be nil if f does not need it. -func parseHeader(ctx context.Context, f fsbridge.File) (elfInfo, error) { +func parseHeader(ctx context.Context, f fullReader) (elfInfo, error) { // Check ident first; it will tell us the endianness of the rest of the // structs. var ident [elf.EI_NIDENT]byte diff --git a/pkg/sentry/loader/loader.go b/pkg/sentry/loader/loader.go index 88449fe95..e65ec4771 100644 --- a/pkg/sentry/loader/loader.go +++ b/pkg/sentry/loader/loader.go @@ -27,7 +27,6 @@ import ( "gvisor.dev/gvisor/pkg/cpuid" "gvisor.dev/gvisor/pkg/rand" "gvisor.dev/gvisor/pkg/sentry/arch" - "gvisor.dev/gvisor/pkg/sentry/fs" "gvisor.dev/gvisor/pkg/sentry/fsbridge" "gvisor.dev/gvisor/pkg/sentry/kernel/auth" "gvisor.dev/gvisor/pkg/sentry/mm" @@ -80,22 +79,6 @@ type LoadArgs struct { Features *cpuid.FeatureSet } -// readFull behaves like io.ReadFull for an *fs.File. -func readFull(ctx context.Context, f *fs.File, dst usermem.IOSequence, offset int64) (int64, error) { - var total int64 - for dst.NumBytes() > 0 { - n, err := f.Preadv(ctx, dst, offset+total) - total += n - if err == io.EOF && total != 0 { - return total, io.ErrUnexpectedEOF - } else if err != nil { - return total, err - } - dst = dst.DropFirst64(n) - } - return total, nil -} - // openPath opens args.Filename and checks that it is valid for loading. // // openPath returns an *fs.Dirent and *fs.File for args.Filename, which is not diff --git a/pkg/sentry/loader/vdso.go b/pkg/sentry/loader/vdso.go index 165869028..05a294fe6 100644 --- a/pkg/sentry/loader/vdso.go +++ b/pkg/sentry/loader/vdso.go @@ -26,10 +26,6 @@ import ( "gvisor.dev/gvisor/pkg/log" "gvisor.dev/gvisor/pkg/safemem" "gvisor.dev/gvisor/pkg/sentry/arch" - "gvisor.dev/gvisor/pkg/sentry/fs" - "gvisor.dev/gvisor/pkg/sentry/fs/anon" - "gvisor.dev/gvisor/pkg/sentry/fs/fsutil" - "gvisor.dev/gvisor/pkg/sentry/fsbridge" "gvisor.dev/gvisor/pkg/sentry/memmap" "gvisor.dev/gvisor/pkg/sentry/mm" "gvisor.dev/gvisor/pkg/sentry/pgalloc" @@ -37,7 +33,6 @@ import ( "gvisor.dev/gvisor/pkg/sentry/usage" "gvisor.dev/gvisor/pkg/syserror" "gvisor.dev/gvisor/pkg/usermem" - "gvisor.dev/gvisor/pkg/waiter" ) const vdsoPrelink = 0xffffffffff700000 @@ -55,52 +50,11 @@ func (f *fileContext) Value(key interface{}) interface{} { } } -// byteReader implements fs.FileOperations for reading from a []byte source. -type byteReader struct { - fsutil.FileNoFsync `state:"nosave"` - fsutil.FileNoIoctl `state:"nosave"` - fsutil.FileNoMMap `state:"nosave"` - fsutil.FileNoSplice `state:"nosave"` - fsutil.FileNoopFlush `state:"nosave"` - fsutil.FileNoopRelease `state:"nosave"` - fsutil.FileNotDirReaddir `state:"nosave"` - fsutil.FilePipeSeek `state:"nosave"` - fsutil.FileUseInodeUnstableAttr `state:"nosave"` - waiter.AlwaysReady `state:"nosave"` - +type byteFullReader struct { data []byte } -var _ fs.FileOperations = (*byteReader)(nil) - -// newByteReaderFile creates a fake file to read data from. -// -// TODO(gvisor.dev/issue/2921): Convert to VFS2. -func newByteReaderFile(ctx context.Context, data []byte) *fs.File { - // Create a fake inode. - inode := fs.NewInode( - ctx, - &fsutil.SimpleFileInode{}, - fs.NewPseudoMountSource(ctx), - fs.StableAttr{ - Type: fs.Anonymous, - DeviceID: anon.PseudoDevice.DeviceID(), - InodeID: anon.PseudoDevice.NextIno(), - BlockSize: usermem.PageSize, - }) - - // Use the fake inode to create a fake dirent. - dirent := fs.NewTransientDirent(inode) - defer dirent.DecRef() - - // Use the fake dirent to make a fake file. - flags := fs.FileFlags{Read: true, Pread: true} - return fs.NewFile(&fileContext{Context: context.Background()}, dirent, flags, &byteReader{ - data: data, - }) -} - -func (b *byteReader) Read(ctx context.Context, file *fs.File, dst usermem.IOSequence, offset int64) (int64, error) { +func (b *byteFullReader) ReadFull(ctx context.Context, dst usermem.IOSequence, offset int64) (int64, error) { if offset < 0 { return 0, syserror.EINVAL } @@ -111,10 +65,6 @@ func (b *byteReader) Read(ctx context.Context, file *fs.File, dst usermem.IOSequ return int64(n), err } -func (b *byteReader) Write(ctx context.Context, file *fs.File, src usermem.IOSequence, offset int64) (int64, error) { - panic("Write not supported") -} - // validateVDSO checks that the VDSO can be loaded by loadVDSO. // // VDSOs are special (see below). Since we are going to map the VDSO directly @@ -130,7 +80,7 @@ func (b *byteReader) Write(ctx context.Context, file *fs.File, src usermem.IOSeq // * PT_LOAD segments don't extend beyond the end of the file. // // ctx may be nil if f does not need it. -func validateVDSO(ctx context.Context, f fsbridge.File, size uint64) (elfInfo, error) { +func validateVDSO(ctx context.Context, f fullReader, size uint64) (elfInfo, error) { info, err := parseHeader(ctx, f) if err != nil { log.Infof("Unable to parse VDSO header: %v", err) @@ -248,13 +198,12 @@ func getSymbolValueFromVDSO(symbol string) (uint64, error) { // PrepareVDSO validates the system VDSO and returns a VDSO, containing the // param page for updating by the kernel. -func PrepareVDSO(ctx context.Context, mfp pgalloc.MemoryFileProvider) (*VDSO, error) { - vdsoFile := fsbridge.NewFSFile(newByteReaderFile(ctx, vdsoBin)) +func PrepareVDSO(mfp pgalloc.MemoryFileProvider) (*VDSO, error) { + vdsoFile := &byteFullReader{data: vdsoBin} // First make sure the VDSO is valid. vdsoFile does not use ctx, so a // nil context can be passed. info, err := validateVDSO(nil, vdsoFile, uint64(len(vdsoBin))) - vdsoFile.DecRef() if err != nil { return nil, err } -- cgit v1.2.3