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debug/buildinfo: read full data segment to lookup buildinfo magic

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Fixes #61644

Change-Id: I7d40c33e65221994bb6865d22dd0994545603ba8
GitHub-Last-Rev: aca92afcbd
GitHub-Pull-Request: golang/go#61649
Reviewed-on: https://go-review.googlesource.com/c/go/+/514075
Run-TryBot: Ian Lance Taylor <iant@google.com>
Reviewed-by: David Chase <drchase@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Auto-Submit: Ian Lance Taylor <iant@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
This commit is contained in:
Alexander Yastrebov 2023-07-29 17:00:35 +00:00 committed by Gopher Robot
parent 1eaeec1095
commit 17d67ed0c9
1 changed files with 26 additions and 23 deletions
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49
src/debug/buildinfo/buildinfo.go
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@ -89,10 +89,10 @@ type exe interface {
// ReadData reads and returns up to size bytes starting at virtual address addr. // ReadData reads and returns up to size bytes starting at virtual address addr.
ReadData(addr, size uint64) ([]byte, error) ReadData(addr, size uint64) ([]byte, error)
// DataStart returns the virtual address of the segment or section that // DataStart returns the virtual address and size of the segment or section that
// should contain build information. This is either a specially named section // should contain build information. This is either a specially named section
// or the first writable non-zero data segment. // or the first writable non-zero data segment.
DataStart() uint64 DataStart() (uint64, uint64)
} }
// readRawBuildInfo extracts the Go toolchain version and module information // readRawBuildInfo extracts the Go toolchain version and module information
@ -148,13 +148,16 @@ func readRawBuildInfo(r io.ReaderAt) (vers, mod string, err error) {
return "", "", errUnrecognizedFormat return "", "", errUnrecognizedFormat
} }
// Read the first 64kB of dataAddr to find the build info blob. // Read segment or section to find the build info blob.
// On some platforms, the blob will be in its own section, and DataStart // On some platforms, the blob will be in its own section, and DataStart
// returns the address of that section. On others, it's somewhere in the // returns the address of that section. On others, it's somewhere in the
// data segment; the linker puts it near the beginning. // data segment; the linker puts it near the beginning.
// See cmd/link/internal/ld.Link.buildinfo. // See cmd/link/internal/ld.Link.buildinfo.
dataAddr := x.DataStart() dataAddr, dataSize := x.DataStart()
data, err := x.ReadData(dataAddr, 64*1024) if dataSize == 0 {
return "", "", errNotGoExe
}
data, err := x.ReadData(dataAddr, dataSize)
if err != nil { if err != nil {
return "", "", err return "", "", err
} }
@ -234,7 +237,7 @@ func hasPlan9Magic(magic []byte) bool {
func decodeString(data []byte) (s string, rest []byte) { func decodeString(data []byte) (s string, rest []byte) {
u, n := binary.Uvarint(data) u, n := binary.Uvarint(data)
if n <= 0 || u >= uint64(len(data)-n) { if n <= 0 || u > uint64(len(data)-n) {
return "", nil return "", nil
} }
return string(data[n : uint64(n)+u]), data[uint64(n)+u:] return string(data[n : uint64(n)+u]), data[uint64(n)+u:]
@ -273,18 +276,18 @@ func (x *elfExe) ReadData(addr, size uint64) ([]byte, error) {
return nil, errUnrecognizedFormat return nil, errUnrecognizedFormat
} }
func (x *elfExe) DataStart() uint64 { func (x *elfExe) DataStart() (uint64, uint64) {
for _, s := range x.f.Sections { for _, s := range x.f.Sections {
if s.Name == ".go.buildinfo" { if s.Name == ".go.buildinfo" {
return s.Addr return s.Addr, s.Size
} }
} }
for _, p := range x.f.Progs { for _, p := range x.f.Progs {
if p.Type == elf.PT_LOAD && p.Flags&(elf.PF_X|elf.PF_W) == elf.PF_W { if p.Type == elf.PT_LOAD && p.Flags&(elf.PF_X|elf.PF_W) == elf.PF_W {
return p.Vaddr return p.Vaddr, p.Memsz
} }
} }
return 0 return 0, 0
} }
// peExe is the PE (Windows Portable Executable) implementation of the exe interface. // peExe is the PE (Windows Portable Executable) implementation of the exe interface.
@ -316,7 +319,7 @@ func (x *peExe) ReadData(addr, size uint64) ([]byte, error) {
return nil, errUnrecognizedFormat return nil, errUnrecognizedFormat
} }
func (x *peExe) DataStart() uint64 { func (x *peExe) DataStart() (uint64, uint64) {
// Assume data is first writable section. // Assume data is first writable section.
const ( const (
IMAGE_SCN_CNT_CODE = 0x00000020 IMAGE_SCN_CNT_CODE = 0x00000020
@ -332,10 +335,10 @@ func (x *peExe) DataStart() uint64 {
for _, sect := range x.f.Sections { for _, sect := range x.f.Sections {
if sect.VirtualAddress != 0 && sect.Size != 0 && if sect.VirtualAddress != 0 && sect.Size != 0 &&
sect.Characteristics&^IMAGE_SCN_ALIGN_32BYTES == IMAGE_SCN_CNT_INITIALIZED_DATA|IMAGE_SCN_MEM_READ|IMAGE_SCN_MEM_WRITE { sect.Characteristics&^IMAGE_SCN_ALIGN_32BYTES == IMAGE_SCN_CNT_INITIALIZED_DATA|IMAGE_SCN_MEM_READ|IMAGE_SCN_MEM_WRITE {
return uint64(sect.VirtualAddress) + x.imageBase() return uint64(sect.VirtualAddress) + x.imageBase(), uint64(sect.VirtualSize)
} }
} }
return 0 return 0, 0
} }
// machoExe is the Mach-O (Apple macOS/iOS) implementation of the exe interface. // machoExe is the Mach-O (Apple macOS/iOS) implementation of the exe interface.
@ -363,11 +366,11 @@ func (x *machoExe) ReadData(addr, size uint64) ([]byte, error) {
return nil, errUnrecognizedFormat return nil, errUnrecognizedFormat
} }
func (x *machoExe) DataStart() uint64 { func (x *machoExe) DataStart() (uint64, uint64) {
// Look for section named "__go_buildinfo". // Look for section named "__go_buildinfo".
for _, sec := range x.f.Sections { for _, sec := range x.f.Sections {
if sec.Name == "__go_buildinfo" { if sec.Name == "__go_buildinfo" {
return sec.Addr return sec.Addr, sec.Size
} }
} }
// Try the first non-empty writable segment. // Try the first non-empty writable segment.
@ -375,10 +378,10 @@ func (x *machoExe) DataStart() uint64 {
for _, load := range x.f.Loads { for _, load := range x.f.Loads {
seg, ok := load.(*macho.Segment) seg, ok := load.(*macho.Segment)
if ok && seg.Addr != 0 && seg.Filesz != 0 && seg.Prot == RW && seg.Maxprot == RW { if ok && seg.Addr != 0 && seg.Filesz != 0 && seg.Prot == RW && seg.Maxprot == RW {
return seg.Addr return seg.Addr, seg.Memsz
} }
} }
return 0 return 0, 0
} }
// xcoffExe is the XCOFF (AIX eXtended COFF) implementation of the exe interface. // xcoffExe is the XCOFF (AIX eXtended COFF) implementation of the exe interface.
@ -399,11 +402,11 @@ func (x *xcoffExe) ReadData(addr, size uint64) ([]byte, error) {
return nil, errors.New("address not mapped") return nil, errors.New("address not mapped")
} }
func (x *xcoffExe) DataStart() uint64 { func (x *xcoffExe) DataStart() (uint64, uint64) {
if s := x.f.SectionByType(xcoff.STYP_DATA); s != nil { if s := x.f.SectionByType(xcoff.STYP_DATA); s != nil {
return s.VirtualAddress return s.VirtualAddress, s.Size
} }
return 0 return 0, 0
} }
// plan9objExe is the Plan 9 a.out implementation of the exe interface. // plan9objExe is the Plan 9 a.out implementation of the exe interface.
@ -411,11 +414,11 @@ type plan9objExe struct {
f *plan9obj.File f *plan9obj.File
} }
func (x *plan9objExe) DataStart() uint64 { func (x *plan9objExe) DataStart() (uint64, uint64) {
if s := x.f.Section("data"); s != nil { if s := x.f.Section("data"); s != nil {
return uint64(s.Offset) return uint64(s.Offset), uint64(s.Size)
} }
return 0 return 0, 0
} }
func (x *plan9objExe) ReadData(addr, size uint64) ([]byte, error) { func (x *plan9objExe) ReadData(addr, size uint64) ([]byte, error) {