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-rw-r--r--pkg/sentry/loader/BUILD16
-rw-r--r--pkg/sentry/loader/elf.go51
-rw-r--r--pkg/sentry/loader/interpreter.go10
-rw-r--r--pkg/sentry/loader/loader.go236
-rw-r--r--pkg/sentry/loader/vdso.go91
5 files changed, 156 insertions, 248 deletions
diff --git a/pkg/sentry/loader/BUILD b/pkg/sentry/loader/BUILD
index 2890393bd..34bdb0b69 100644
--- a/pkg/sentry/loader/BUILD
+++ b/pkg/sentry/loader/BUILD
@@ -1,5 +1,4 @@
-load("@io_bazel_rules_go//go:def.bzl", "go_embed_data")
-load("//tools/go_stateify:defs.bzl", "go_library")
+load("//tools:defs.bzl", "go_embed_data", "go_library")
package(licenses = ["notice"])
@@ -20,31 +19,28 @@ go_library(
"vdso_state.go",
":vdso_bin",
],
- importpath = "gvisor.dev/gvisor/pkg/sentry/loader",
visibility = ["//pkg/sentry:internal"],
deps = [
"//pkg/abi",
"//pkg/abi/linux",
"//pkg/binary",
+ "//pkg/context",
"//pkg/cpuid",
"//pkg/log",
"//pkg/rand",
+ "//pkg/safemem",
"//pkg/sentry/arch",
- "//pkg/sentry/context",
- "//pkg/sentry/fs",
- "//pkg/sentry/fs/anon",
- "//pkg/sentry/fs/fsutil",
+ "//pkg/sentry/fsbridge",
"//pkg/sentry/kernel/auth",
"//pkg/sentry/limits",
"//pkg/sentry/memmap",
"//pkg/sentry/mm",
"//pkg/sentry/pgalloc",
- "//pkg/sentry/safemem",
"//pkg/sentry/uniqueid",
"//pkg/sentry/usage",
- "//pkg/sentry/usermem",
+ "//pkg/sentry/vfs",
"//pkg/syserr",
"//pkg/syserror",
- "//pkg/waiter",
+ "//pkg/usermem",
],
)
diff --git a/pkg/sentry/loader/elf.go b/pkg/sentry/loader/elf.go
index 3ea037e4d..20dd1cc21 100644
--- a/pkg/sentry/loader/elf.go
+++ b/pkg/sentry/loader/elf.go
@@ -23,16 +23,16 @@ import (
"gvisor.dev/gvisor/pkg/abi"
"gvisor.dev/gvisor/pkg/abi/linux"
"gvisor.dev/gvisor/pkg/binary"
+ "gvisor.dev/gvisor/pkg/context"
"gvisor.dev/gvisor/pkg/cpuid"
"gvisor.dev/gvisor/pkg/log"
"gvisor.dev/gvisor/pkg/sentry/arch"
- "gvisor.dev/gvisor/pkg/sentry/context"
- "gvisor.dev/gvisor/pkg/sentry/fs"
+ "gvisor.dev/gvisor/pkg/sentry/fsbridge"
"gvisor.dev/gvisor/pkg/sentry/limits"
"gvisor.dev/gvisor/pkg/sentry/memmap"
"gvisor.dev/gvisor/pkg/sentry/mm"
- "gvisor.dev/gvisor/pkg/sentry/usermem"
"gvisor.dev/gvisor/pkg/syserror"
+ "gvisor.dev/gvisor/pkg/usermem"
)
const (
@@ -90,18 +90,27 @@ 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 *fs.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
- _, err := readFull(ctx, f, usermem.BytesIOSequence(ident[:]), 0)
+ _, err := f.ReadFull(ctx, usermem.BytesIOSequence(ident[:]), 0)
if err != nil {
log.Infof("Error reading ELF ident: %v", err)
// The entire ident array always exists.
@@ -137,7 +146,7 @@ func parseHeader(ctx context.Context, f *fs.File) (elfInfo, error) {
var hdr elf.Header64
hdrBuf := make([]byte, header64Size)
- _, err = readFull(ctx, f, usermem.BytesIOSequence(hdrBuf), 0)
+ _, err = f.ReadFull(ctx, usermem.BytesIOSequence(hdrBuf), 0)
if err != nil {
log.Infof("Error reading ELF header: %v", err)
// The entire header always exists.
@@ -187,7 +196,7 @@ func parseHeader(ctx context.Context, f *fs.File) (elfInfo, error) {
}
phdrBuf := make([]byte, totalPhdrSize)
- _, err = readFull(ctx, f, usermem.BytesIOSequence(phdrBuf), int64(hdr.Phoff))
+ _, err = f.ReadFull(ctx, usermem.BytesIOSequence(phdrBuf), int64(hdr.Phoff))
if err != nil {
log.Infof("Error reading ELF phdrs: %v", err)
// If phdrs were specified, they should all exist.
@@ -227,7 +236,7 @@ func parseHeader(ctx context.Context, f *fs.File) (elfInfo, error) {
// mapSegment maps a phdr into the Task. offset is the offset to apply to
// phdr.Vaddr.
-func mapSegment(ctx context.Context, m *mm.MemoryManager, f *fs.File, phdr *elf.ProgHeader, offset usermem.Addr) error {
+func mapSegment(ctx context.Context, m *mm.MemoryManager, f fsbridge.File, phdr *elf.ProgHeader, offset usermem.Addr) error {
// We must make a page-aligned mapping.
adjust := usermem.Addr(phdr.Vaddr).PageOffset()
@@ -272,7 +281,7 @@ func mapSegment(ctx context.Context, m *mm.MemoryManager, f *fs.File, phdr *elf.
}
defer func() {
if mopts.MappingIdentity != nil {
- mopts.MappingIdentity.DecRef()
+ mopts.MappingIdentity.DecRef(ctx)
}
}()
if err := f.ConfigureMMap(ctx, &mopts); err != nil {
@@ -395,7 +404,7 @@ type loadedELF struct {
//
// Preconditions:
// * f is an ELF file
-func loadParsedELF(ctx context.Context, m *mm.MemoryManager, f *fs.File, info elfInfo, sharedLoadOffset usermem.Addr) (loadedELF, error) {
+func loadParsedELF(ctx context.Context, m *mm.MemoryManager, f fsbridge.File, info elfInfo, sharedLoadOffset usermem.Addr) (loadedELF, error) {
first := true
var start, end usermem.Addr
var interpreter string
@@ -408,6 +417,8 @@ func loadParsedELF(ctx context.Context, m *mm.MemoryManager, f *fs.File, info el
start = vaddr
}
if vaddr < end {
+ // NOTE(b/37474556): Linux allows out-of-order
+ // segments, in violation of the spec.
ctx.Infof("PT_LOAD headers out-of-order. %#x < %#x", vaddr, end)
return loadedELF{}, syserror.ENOEXEC
}
@@ -429,7 +440,7 @@ func loadParsedELF(ctx context.Context, m *mm.MemoryManager, f *fs.File, info el
}
path := make([]byte, phdr.Filesz)
- _, err := readFull(ctx, f, usermem.BytesIOSequence(path), int64(phdr.Off))
+ _, err := f.ReadFull(ctx, usermem.BytesIOSequence(path), int64(phdr.Off))
if err != nil {
// If an interpreter was specified, it should exist.
ctx.Infof("Error reading PT_INTERP path: %v", err)
@@ -562,7 +573,7 @@ func loadParsedELF(ctx context.Context, m *mm.MemoryManager, f *fs.File, info el
// Preconditions:
// * f is an ELF file
// * f is the first ELF loaded into m
-func loadInitialELF(ctx context.Context, m *mm.MemoryManager, fs *cpuid.FeatureSet, f *fs.File) (loadedELF, arch.Context, error) {
+func loadInitialELF(ctx context.Context, m *mm.MemoryManager, fs *cpuid.FeatureSet, f fsbridge.File) (loadedELF, arch.Context, error) {
info, err := parseHeader(ctx, f)
if err != nil {
ctx.Infof("Failed to parse initial ELF: %v", err)
@@ -600,7 +611,7 @@ func loadInitialELF(ctx context.Context, m *mm.MemoryManager, fs *cpuid.FeatureS
//
// Preconditions:
// * f is an ELF file
-func loadInterpreterELF(ctx context.Context, m *mm.MemoryManager, f *fs.File, initial loadedELF) (loadedELF, error) {
+func loadInterpreterELF(ctx context.Context, m *mm.MemoryManager, f fsbridge.File, initial loadedELF) (loadedELF, error) {
info, err := parseHeader(ctx, f)
if err != nil {
if err == syserror.ENOEXEC {
@@ -644,17 +655,17 @@ func loadELF(ctx context.Context, args LoadArgs) (loadedELF, arch.Context, error
// resolved, the interpreter should still be resolved if it is
// a symlink.
args.ResolveFinal = true
+ // Refresh the traversal limit.
+ *args.RemainingTraversals = linux.MaxSymlinkTraversals
args.Filename = bin.interpreter
- d, i, err := openPath(ctx, args)
+ intFile, err := openPath(ctx, args)
if err != nil {
ctx.Infof("Error opening interpreter %s: %v", bin.interpreter, err)
return loadedELF{}, nil, err
}
- defer i.DecRef()
- // We don't need the Dirent.
- d.DecRef()
+ defer intFile.DecRef(ctx)
- interp, err = loadInterpreterELF(ctx, args.MemoryManager, i, bin)
+ interp, err = loadInterpreterELF(ctx, args.MemoryManager, intFile, bin)
if err != nil {
ctx.Infof("Error loading interpreter: %v", err)
return loadedELF{}, nil, err
diff --git a/pkg/sentry/loader/interpreter.go b/pkg/sentry/loader/interpreter.go
index ccf909cac..3886b4d33 100644
--- a/pkg/sentry/loader/interpreter.go
+++ b/pkg/sentry/loader/interpreter.go
@@ -18,10 +18,10 @@ import (
"bytes"
"io"
- "gvisor.dev/gvisor/pkg/sentry/context"
- "gvisor.dev/gvisor/pkg/sentry/fs"
- "gvisor.dev/gvisor/pkg/sentry/usermem"
+ "gvisor.dev/gvisor/pkg/context"
+ "gvisor.dev/gvisor/pkg/sentry/fsbridge"
"gvisor.dev/gvisor/pkg/syserror"
+ "gvisor.dev/gvisor/pkg/usermem"
)
const (
@@ -37,9 +37,9 @@ const (
)
// parseInterpreterScript returns the interpreter path and argv.
-func parseInterpreterScript(ctx context.Context, filename string, f *fs.File, argv []string) (newpath string, newargv []string, err error) {
+func parseInterpreterScript(ctx context.Context, filename string, f fsbridge.File, argv []string) (newpath string, newargv []string, err error) {
line := make([]byte, interpMaxLineLength)
- n, err := readFull(ctx, f, usermem.BytesIOSequence(line), 0)
+ n, err := f.ReadFull(ctx, usermem.BytesIOSequence(line), 0)
// Short read is OK.
if err != nil && err != io.ErrUnexpectedEOF {
if err == io.EOF {
diff --git a/pkg/sentry/loader/loader.go b/pkg/sentry/loader/loader.go
index 818941762..8d6802ea3 100644
--- a/pkg/sentry/loader/loader.go
+++ b/pkg/sentry/loader/loader.go
@@ -23,16 +23,17 @@ import (
"gvisor.dev/gvisor/pkg/abi"
"gvisor.dev/gvisor/pkg/abi/linux"
+ "gvisor.dev/gvisor/pkg/context"
"gvisor.dev/gvisor/pkg/cpuid"
"gvisor.dev/gvisor/pkg/rand"
"gvisor.dev/gvisor/pkg/sentry/arch"
- "gvisor.dev/gvisor/pkg/sentry/context"
- "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"
- "gvisor.dev/gvisor/pkg/sentry/usermem"
+ "gvisor.dev/gvisor/pkg/sentry/vfs"
"gvisor.dev/gvisor/pkg/syserr"
"gvisor.dev/gvisor/pkg/syserror"
+ "gvisor.dev/gvisor/pkg/usermem"
)
// LoadArgs holds specifications for an executable file to be loaded.
@@ -40,16 +41,6 @@ type LoadArgs struct {
// MemoryManager is the memory manager to load the executable into.
MemoryManager *mm.MemoryManager
- // Mounts is the mount namespace in which to look up Filename.
- Mounts *fs.MountNamespace
-
- // Root is the root directory under which to look up Filename.
- Root *fs.Dirent
-
- // WorkingDirectory is the working directory under which to look up
- // Filename.
- WorkingDirectory *fs.Dirent
-
// RemainingTraversals is the maximum number of symlinks to follow to
// resolve Filename. This counter is passed by reference to keep it
// updated throughout the call stack.
@@ -64,7 +55,18 @@ type LoadArgs struct {
// File is an open fs.File object of the executable. If File is not
// nil, then File will be loaded and Filename will be ignored.
- File *fs.File
+ //
+ // The caller is responsible for checking that the user can execute this file.
+ File fsbridge.File
+
+ // Opener is used to open the executable file when 'File' is nil.
+ Opener fsbridge.Lookup
+
+ // CloseOnExec indicates that the executable (or one of its parent
+ // directories) was opened with O_CLOEXEC. If the executable is an
+ // interpreter script, then cause an ENOENT error to occur, since the
+ // script would otherwise be inaccessible to the interpreter.
+ CloseOnExec bool
// Argv is the vector of arguments to pass to the executable.
Argv []string
@@ -77,135 +79,41 @@ 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 for loading.
+// openPath opens args.Filename and checks that it is valid for loading.
//
-// openPath returns the fs.Dirent and an *fs.File for args.Filename, which is
-// not installed in the Task FDTable. The caller takes ownership of both.
+// openPath returns an *fs.Dirent and *fs.File for args.Filename, which is not
+// installed in the Task FDTable. The caller takes ownership of both.
//
// args.Filename must be a readable, executable, regular file.
-func openPath(ctx context.Context, args LoadArgs) (*fs.Dirent, *fs.File, error) {
- var err error
+func openPath(ctx context.Context, args LoadArgs) (fsbridge.File, error) {
if args.Filename == "" {
ctx.Infof("cannot open empty name")
- return nil, nil, syserror.ENOENT
- }
-
- var d *fs.Dirent
- if args.ResolveFinal {
- d, err = args.Mounts.FindInode(ctx, args.Root, args.WorkingDirectory, args.Filename, args.RemainingTraversals)
- } else {
- d, err = args.Mounts.FindLink(ctx, args.Root, args.WorkingDirectory, args.Filename, args.RemainingTraversals)
- }
- if err != nil {
- return nil, nil, err
- }
-
- // Open file will take a reference to Dirent, so destroy this one.
- defer d.DecRef()
-
- if !args.ResolveFinal && fs.IsSymlink(d.Inode.StableAttr) {
- return nil, nil, syserror.ELOOP
- }
-
- return openFile(ctx, nil, d, args.Filename)
-}
-
-// openFile takes that file's Dirent and performs checks on it. If provided a
-// *fs.Dirent and not a *fs.File, it creates a *fs.File object from the Dirent's
-// Inode and performs checks on that.
-//
-// openFile returns an *fs.File and *fs.Dirent, and the caller takes ownership
-// of both.
-//
-// "dirent" and "file" must not both be nil and point to a readable, executable, regular file.
-func openFile(ctx context.Context, file *fs.File, dirent *fs.Dirent, name string) (*fs.Dirent, *fs.File, error) {
- // file and dirent must not be nil.
- if dirent == nil && file == nil {
- ctx.Infof("dirent and file cannot both be nil.")
- return nil, nil, syserror.ENOENT
- }
-
- if file != nil {
- dirent = file.Dirent
- }
-
- // Perform permissions checks on the file.
- if err := checkFile(ctx, dirent, name); err != nil {
- return nil, nil, err
+ return nil, syserror.ENOENT
}
- if file == nil {
- var ferr error
- if file, ferr = dirent.Inode.GetFile(ctx, dirent, fs.FileFlags{Read: true}); ferr != nil {
- return nil, nil, ferr
- }
- } else {
- // GetFile takes a reference to the created file, so make one in the case
- // that the file reference already existed.
- file.IncRef()
- }
-
- // We must be able to read at arbitrary offsets.
- if !file.Flags().Pread {
- file.DecRef()
- ctx.Infof("%s cannot be read at an offset: %+v", file.MappedName(ctx), file.Flags())
- return nil, nil, syserror.EACCES
+ // TODO(gvisor.dev/issue/160): Linux requires only execute permission,
+ // not read. However, our backing filesystems may prevent us from reading
+ // the file without read permission. Additionally, a task with a
+ // non-readable executable has additional constraints on access via
+ // ptrace and procfs.
+ opts := vfs.OpenOptions{
+ Flags: linux.O_RDONLY,
+ FileExec: true,
}
-
- // Grab reference for caller.
- dirent.IncRef()
- return dirent, file, nil
+ return args.Opener.OpenPath(ctx, args.Filename, opts, args.RemainingTraversals, args.ResolveFinal)
}
-// checkFile performs file permissions checks for binaries called in openPath
-// and openFile
-func checkFile(ctx context.Context, d *fs.Dirent, name string) error {
- perms := fs.PermMask{
- // TODO(gvisor.dev/issue/160): Linux requires only execute
- // permission, not read. However, our backing filesystems may
- // prevent us from reading the file without read permission.
- //
- // Additionally, a task with a non-readable executable has
- // additional constraints on access via ptrace and procfs.
- Read: true,
- Execute: true,
- }
- if err := d.Inode.CheckPermission(ctx, perms); err != nil {
+// checkIsRegularFile prevents us from trying to execute a directory, pipe, etc.
+func checkIsRegularFile(ctx context.Context, file fsbridge.File, filename string) error {
+ t, err := file.Type(ctx)
+ if err != nil {
return err
}
-
- // If they claim it's a directory, then make sure.
- //
- // N.B. we reject directories below, but we must first reject
- // non-directories passed as directories.
- if len(name) > 0 && name[len(name)-1] == '/' && !fs.IsDir(d.Inode.StableAttr) {
- return syserror.ENOTDIR
- }
-
- // No exec-ing directories, pipes, etc!
- if !fs.IsRegular(d.Inode.StableAttr) {
- ctx.Infof("%s is not regular: %v", name, d.Inode.StableAttr)
+ if t != linux.ModeRegular {
+ ctx.Infof("%q is not a regular file: %v", filename, t)
return syserror.EACCES
}
-
return nil
-
}
// allocStack allocates and maps a stack in to any available part of the address space.
@@ -224,8 +132,10 @@ const (
maxLoaderAttempts = 6
)
-// loadExecutable loads an executable that is pointed to by args.File. If nil,
-// the path args.Filename is resolved and loaded. If the executable is an
+// loadExecutable loads an executable that is pointed to by args.File. The
+// caller is responsible for checking that the user can execute this file.
+// If nil, the path args.Filename is resolved and loaded (check that the user
+// can execute this file is done here in this case). If the executable is an
// interpreter script rather than an ELF, the binary of the corresponding
// interpreter will be loaded.
//
@@ -234,33 +144,29 @@ const (
// * arch.Context matching the binary arch
// * fs.Dirent of the binary file
// * Possibly updated args.Argv
-func loadExecutable(ctx context.Context, args LoadArgs) (loadedELF, arch.Context, *fs.Dirent, []string, error) {
+func loadExecutable(ctx context.Context, args LoadArgs) (loadedELF, arch.Context, fsbridge.File, []string, error) {
for i := 0; i < maxLoaderAttempts; i++ {
- var (
- d *fs.Dirent
- err error
- )
if args.File == nil {
- d, args.File, err = openPath(ctx, args)
+ var err error
+ args.File, err = openPath(ctx, args)
+ if err != nil {
+ ctx.Infof("Error opening %s: %v", args.Filename, err)
+ return loadedELF{}, nil, nil, nil, err
+ }
+ // Ensure file is release in case the code loops or errors out.
+ defer args.File.DecRef(ctx)
} else {
- d, args.File, err = openFile(ctx, args.File, nil, "")
- }
-
- if err != nil {
- ctx.Infof("Error opening %s: %v", args.Filename, err)
- return loadedELF{}, nil, nil, nil, err
+ if err := checkIsRegularFile(ctx, args.File, args.Filename); err != nil {
+ return loadedELF{}, nil, nil, nil, err
+ }
}
- defer args.File.DecRef()
- // We will return d in the successful case, but defer a DecRef
- // for intermediate loops and failure cases.
- defer d.DecRef()
// Check the header. Is this an ELF or interpreter script?
var hdr [4]uint8
// N.B. We assume that reading from a regular file cannot block.
- _, err = readFull(ctx, args.File, usermem.BytesIOSequence(hdr[:]), 0)
- // Allow unexpected EOF, as a valid executable could be only
- // three bytes (e.g., #!a).
+ _, err := args.File.ReadFull(ctx, usermem.BytesIOSequence(hdr[:]), 0)
+ // Allow unexpected EOF, as a valid executable could be only three bytes
+ // (e.g., #!a).
if err != nil && err != io.ErrUnexpectedEOF {
if err == io.EOF {
err = syserror.ENOEXEC
@@ -275,15 +181,22 @@ func loadExecutable(ctx context.Context, args LoadArgs) (loadedELF, arch.Context
ctx.Infof("Error loading ELF: %v", err)
return loadedELF{}, nil, nil, nil, err
}
- // An ELF is always terminal. Hold on to d.
- d.IncRef()
- return loaded, ac, d, args.Argv, err
+ // An ELF is always terminal. Hold on to file.
+ args.File.IncRef()
+ return loaded, ac, args.File, args.Argv, err
+
case bytes.Equal(hdr[:2], []byte(interpreterScriptMagic)):
+ if args.CloseOnExec {
+ return loadedELF{}, nil, nil, nil, syserror.ENOENT
+ }
args.Filename, args.Argv, err = parseInterpreterScript(ctx, args.Filename, args.File, args.Argv)
if err != nil {
ctx.Infof("Error loading interpreter script: %v", err)
return loadedELF{}, nil, nil, nil, err
}
+ // Refresh the traversal limit for the interpreter.
+ *args.RemainingTraversals = linux.MaxSymlinkTraversals
+
default:
ctx.Infof("Unknown magic: %v", hdr)
return loadedELF{}, nil, nil, nil, syserror.ENOEXEC
@@ -306,16 +219,16 @@ func loadExecutable(ctx context.Context, args LoadArgs) (loadedELF, arch.Context
// * Load is called on the Task goroutine.
func Load(ctx context.Context, args LoadArgs, extraAuxv []arch.AuxEntry, vdso *VDSO) (abi.OS, arch.Context, string, *syserr.Error) {
// Load the executable itself.
- loaded, ac, d, newArgv, err := loadExecutable(ctx, args)
+ loaded, ac, file, newArgv, err := loadExecutable(ctx, args)
if err != nil {
- return 0, nil, "", syserr.NewDynamic(fmt.Sprintf("Failed to load %s: %v", args.Filename, err), syserr.FromError(err).ToLinux())
+ return 0, nil, "", syserr.NewDynamic(fmt.Sprintf("failed to load %s: %v", args.Filename, err), syserr.FromError(err).ToLinux())
}
- defer d.DecRef()
+ defer file.DecRef(ctx)
// Load the VDSO.
vdsoAddr, err := loadVDSO(ctx, args.MemoryManager, vdso, loaded)
if err != nil {
- return 0, nil, "", syserr.NewDynamic(fmt.Sprintf("Error loading VDSO: %v", err), syserr.FromError(err).ToLinux())
+ return 0, nil, "", syserr.NewDynamic(fmt.Sprintf("error loading VDSO: %v", err), syserr.FromError(err).ToLinux())
}
// Setup the heap. brk starts at the next page after the end of the
@@ -379,7 +292,16 @@ func Load(ctx context.Context, args LoadArgs, extraAuxv []arch.AuxEntry, vdso *V
m.SetEnvvStart(sl.EnvvStart)
m.SetEnvvEnd(sl.EnvvEnd)
m.SetAuxv(auxv)
- m.SetExecutable(d)
+ m.SetExecutable(ctx, file)
+
+ symbolValue, err := getSymbolValueFromVDSO("rt_sigreturn")
+ if err != nil {
+ return 0, nil, "", syserr.NewDynamic(fmt.Sprintf("Failed to find rt_sigreturn in vdso: %v", err), syserr.FromError(err).ToLinux())
+ }
+
+ // Found rt_sigretrun.
+ addr := uint64(vdsoAddr) + symbolValue - vdsoPrelink
+ m.SetVDSOSigReturn(addr)
ac.SetIP(uintptr(loaded.entry))
ac.SetStack(uintptr(stack.Bottom))
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
}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-17 05:34:56 +0000