debug/elf: use saferio to read section data

For #47653
Fixes #45599
Fixes #52522

Change-Id: Id6a80186434080cb0a205978ad7f224252674604
Reviewed-on: https://go-review.googlesource.com/c/go/+/408679
Auto-Submit: Ian Lance Taylor <iant@google.com>
Reviewed-by: Than McIntosh <thanm@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Tobias Klauser <tobias.klauser@gmail.com>
Run-TryBot: Ian Lance Taylor <iant@google.com>

diff --git a/src/debug/elf/file.go b/src/debug/elf/file.go
index 6bfcd2a3f8490a1749bde34dc87e2bc3c752272f..95c28c143349f647d4ea5b765b9c0bc0460e175b 100644 (file)
--- a/src/debug/elf/file.go
+++ b/src/debug/elf/file.go
@@ -12,6 +12,7 @@ import (
        "encoding/binary"
        "errors"
        "fmt"
+       "internal/saferio"
        "io"
        "os"
        "strings"
@@ -102,9 +103,7 @@ type Section struct {
 // Even if the section is stored compressed in the ELF file,
 // Data returns uncompressed data.
 func (s *Section) Data() ([]byte, error) {
-       dat := make([]byte, s.Size)
-       n, err := io.ReadFull(s.Open(), dat)
-       return dat[0:n], err
+       return saferio.ReadData(s.Open(), s.Size)
 }
 
 // stringTable reads and returns the string table given by the
@@ -1213,10 +1212,7 @@ func (f *File) DWARF() (*dwarf.Data, error) {
                if err != nil && uint64(len(b)) < s.Size {
                        return nil, err
                }
-               var (
-                       dlen uint64
-                       dbuf []byte
-               )
+               var dlen uint64
                if len(b) >= 12 && string(b[:4]) == "ZLIB" {
                        dlen = binary.BigEndian.Uint64(b[4:12])
                        s.compressionOffset = 12
@@ -1242,18 +1238,17 @@ func (f *File) DWARF() (*dwarf.Data, error) {
                        }
                }
                if dlen > 0 {
-                       dbuf = make([]byte, dlen)
                        r, err := zlib.NewReader(bytes.NewBuffer(b[s.compressionOffset:]))
                        if err != nil {
                                return nil, err
                        }
-                       if _, err := io.ReadFull(r, dbuf); err != nil {
+                       b, err = saferio.ReadData(r, dlen)
+                       if err != nil {
                                return nil, err
                        }
                        if err := r.Close(); err != nil {
                                return nil, err
                        }
-                       b = dbuf
                }
 
                if f.Type == ET_EXEC {