diff options
Diffstat (limited to 'pkg/sentry/loader/vdso.go')
| -rw-r--r-- | pkg/sentry/loader/vdso.go | 91 |
1 files changed, 35 insertions, 56 deletions
diff --git a/pkg/sentry/loader/vdso.go b/pkg/sentry/loader/vdso.go index ada28aea3..05a294fe6 100644 --- a/pkg/sentry/loader/vdso.go +++ b/pkg/sentry/loader/vdso.go @@ -15,28 +15,28 @@ package loader import ( + "bytes" "debug/elf" "fmt" "io" + "strings" "gvisor.dev/gvisor/pkg/abi" + "gvisor.dev/gvisor/pkg/context" "gvisor.dev/gvisor/pkg/log" + "gvisor.dev/gvisor/pkg/safemem" "gvisor.dev/gvisor/pkg/sentry/arch" - "gvisor.dev/gvisor/pkg/sentry/context" - "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/memmap" "gvisor.dev/gvisor/pkg/sentry/mm" "gvisor.dev/gvisor/pkg/sentry/pgalloc" - "gvisor.dev/gvisor/pkg/sentry/safemem" "gvisor.dev/gvisor/pkg/sentry/uniqueid" "gvisor.dev/gvisor/pkg/sentry/usage" - "gvisor.dev/gvisor/pkg/sentry/usermem" "gvisor.dev/gvisor/pkg/syserror" - "gvisor.dev/gvisor/pkg/waiter" + "gvisor.dev/gvisor/pkg/usermem" ) +const vdsoPrelink = 0xffffffffff700000 + type fileContext struct { context.Context } @@ -50,50 +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. -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 } @@ -104,10 +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 @@ -123,7 +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 *fs.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) @@ -218,15 +175,35 @@ type VDSO struct { phdrs []elf.ProgHeader `state:".([]elfProgHeader)"` } +// getSymbolValueFromVDSO returns the specific symbol value in vdso.so. +func getSymbolValueFromVDSO(symbol string) (uint64, error) { + f, err := elf.NewFile(bytes.NewReader(vdsoBin)) + if err != nil { + return 0, err + } + syms, err := f.Symbols() + if err != nil { + return 0, err + } + + for _, sym := range syms { + if elf.ST_BIND(sym.Info) != elf.STB_LOCAL && sym.Section != elf.SHN_UNDEF { + if strings.Contains(sym.Name, symbol) { + return sym.Value, nil + } + } + } + return 0, fmt.Errorf("no %v in vdso.so", symbol) +} + // 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 := 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 } @@ -268,6 +245,8 @@ func PrepareVDSO(ctx context.Context, mfp pgalloc.MemoryFileProvider) (*VDSO, er // some applications may not be able to handle multiple [vdso] // hints. vdso: mm.NewSpecialMappable("", mfp, vdso), + os: info.os, + arch: info.arch, phdrs: info.phdrs, }, nil } |