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Diffstat (limited to 'pkg/sentry/loader/elf.go')
-rw-r--r--pkg/sentry/loader/elf.go51
1 files changed, 31 insertions, 20 deletions
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
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-08 01:06:30 +0000