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golang: Enforce maximum allocation size
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@2opremio
2opremio committed Nov 15, 2023
1 parent 70a8851 commit bc3719f
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Showing 9 changed files with 576 additions and 390 deletions.
57 changes: 40 additions & 17 deletions lib/xdrgen/generators/go.rb
View file
Original file line number Diff line number Diff line change
Expand Up @@ -536,7 +536,7 @@ def check_error(str)
def render_struct_decode_from_interface(out, struct)
name = name(struct)
out.puts "// DecodeFrom decodes this value using the Decoder."
out.puts "func (s *#{name}) DecodeFrom(d *xdr.Decoder, maxDepth uint) (int, error) {"
out.puts "func (s *#{name}) DecodeFrom(d *xdr.Decoder, maxDepth uint, maxAllocSize int) (int, error) {"
out.puts " if maxDepth == 0 {"
out.puts " return 0, fmt.Errorf(\"decoding #{name}: %w\", ErrMaxDecodingDepthReached)"
out.puts " }"
Expand All @@ -556,7 +556,7 @@ def render_struct_decode_from_interface(out, struct)
def render_union_decode_from_interface(out, union)
name = name(union)
out.puts "// DecodeFrom decodes this value using the Decoder."
out.puts "func (u *#{name}) DecodeFrom(d *xdr.Decoder, maxDepth uint) (int, error) {"
out.puts "func (u *#{name}) DecodeFrom(d *xdr.Decoder, maxDepth uint, maxAllocSize int) (int, error) {"
out.puts " if maxDepth == 0 {"
out.puts " return 0, fmt.Errorf(\"decoding #{name}: %w\", ErrMaxDecodingDepthReached)"
out.puts " }"
Expand Down Expand Up @@ -589,7 +589,7 @@ def render_enum_decode_from_interface(out, typedef)
type = typedef
out.puts <<-EOS.strip_heredoc
// DecodeFrom decodes this value using the Decoder.
func (e *#{name}) DecodeFrom(d *xdr.Decoder, maxDepth uint) (int, error) {
func (e *#{name}) DecodeFrom(d *xdr.Decoder, maxDepth uint, maxAllocSize int) (int, error) {
if maxDepth == 0 {
return 0, fmt.Errorf("decoding #{name}: %w", ErrMaxDecodingDepthReached)
}
Expand All @@ -611,7 +611,7 @@ def render_typedef_decode_from_interface(out, typedef)
name = name(typedef)
type = typedef.declaration.type
out.puts "// DecodeFrom decodes this value using the Decoder."
out.puts "func (s *#{name}) DecodeFrom(d *xdr.Decoder, maxDepth uint) (int, error) {"
out.puts "func (s *#{name}) DecodeFrom(d *xdr.Decoder, maxDepth uint, maxAllocSize int) (int, error) {"
out.puts " if maxDepth == 0 {"
out.puts " return 0, fmt.Errorf(\"decoding #{name}: %w\", ErrMaxDecodingDepthReached)"
out.puts " }"
Expand Down Expand Up @@ -681,17 +681,17 @@ def render_decode_from_body(out, var, type, declared_variables:, self_encode:)
out.puts " #{var}, nTmp, err = d.DecodeBool()"
out.puts tail
when AST::Typespecs::String
arg = "0"
arg = type.decl.resolved_size unless type.decl.resolved_size.nil?
arg = "maxAllocSize"
arg = "mergeMaxAllocSizeAndMaxSize(maxAllocSize, #{type.decl.resolved_size})" unless type.decl.resolved_size.nil?
out.puts " #{var}, nTmp, err = d.DecodeString(#{arg})"
out.puts tail
when AST::Typespecs::Opaque
if type.fixed?
out.puts " nTmp, err = d.DecodeFixedOpaqueInplace(#{var}[:])"
out.puts tail
else
arg = "0"
arg = type.decl.resolved_size unless type.decl.resolved_size.nil?
arg = "maxAllocSize"
arg = "mergeMaxAllocSizeAndMaxSize(maxAllocSize, #{type.decl.resolved_size})" unless type.decl.resolved_size.nil?
out.puts " #{var}, nTmp, err = d.DecodeOpaque(#{arg})"
out.puts tail
end
Expand All @@ -708,7 +708,7 @@ def render_decode_from_body(out, var, type, declared_variables:, self_encode:)
out.puts " #{var} = new(#{name type.resolved_type.declaration.type})"
end
var = "(*#{name type})(#{var})" if self_encode
out.puts " nTmp, err = #{var}.DecodeFrom(d, maxDepth)"
out.puts " nTmp, err = #{var}.DecodeFrom(d, maxDepth, maxAllocSize)"
out.puts tail
if optional_within
out.puts " }"
Expand All @@ -725,7 +725,7 @@ def render_decode_from_body(out, var, type, declared_variables:, self_encode:)
out.puts " if eb {"
var = "(*#{element_var})"
end
out.puts " nTmp, err = #{element_var}.DecodeFrom(d, maxDepth)"
out.puts " nTmp, err = #{element_var}.DecodeFrom(d, maxDepth, maxAllocSize)"
out.puts tail
if optional_within
out.puts " }"
Expand All @@ -740,6 +740,13 @@ def render_decode_from_body(out, var, type, declared_variables:, self_encode:)
out.puts " return n, fmt.Errorf(\"decoding #{name type}: data size (%d) exceeds size limit (#{type.decl.resolved_size})\", l)"
out.puts " }"
end
out.puts " if maxAllocSize > 0 {"
out.puts " var phony #{name type}"
out.puts " allocSize := unsafe.Sizeof(phony) * uintptr(l)"
out.puts " if uintptr(maxAllocSize) < allocSize {"
out.puts " return n, fmt.Errorf(\"decoding #{name type}: allocation size (%d) exceeds limit (%d)\", allocSize, maxAllocSize)"
out.puts " }"
out.puts " }"
out.puts " #{var} = nil"
out.puts " if l > 0 {"
out.puts " #{var} = make([]#{name type}, l)"
Expand All @@ -755,7 +762,7 @@ def render_decode_from_body(out, var, type, declared_variables:, self_encode:)
out.puts " #{element_var} = new(#{name type.resolved_type.declaration.type})"
var = "(*#{element_var})"
end
out.puts " nTmp, err = #{element_var}.DecodeFrom(d, maxDepth)"
out.puts " nTmp, err = #{element_var}.DecodeFrom(d, maxDepth, maxAllocSize)"
out.puts tail
if optional_within
out.puts " }"
Expand All @@ -767,13 +774,13 @@ def render_decode_from_body(out, var, type, declared_variables:, self_encode:)
end
when AST::Definitions::Base
if self_encode
out.puts " nTmp, err = #{name type}(#{var}).DecodeFrom(d, maxDepth)"
out.puts " nTmp, err = #{name type}(#{var}).DecodeFrom(d, maxDepth, maxAllocSize)"
else
out.puts " nTmp, err = #{var}.DecodeFrom(d, maxDepth)"
out.puts " nTmp, err = #{var}.DecodeFrom(d, maxDepth, maxAllocSize)"
end
out.puts tail
else
out.puts " nTmp, err = d.DecodeWithMaxDepth(&#{var}, maxDepth)"
out.puts " nTmp, err = d.DecodeWithMaxDepth(&#{var}, maxDepth, maxAllocSize)"
out.puts tail
end
if optional
Expand All @@ -794,7 +801,7 @@ def render_binary_interface(out, name)
out.puts "func (s *#{name}) UnmarshalBinary(inp []byte) error {"
out.puts " r := bytes.NewReader(inp)"
out.puts " d := xdr.NewDecoder(r)"
out.puts " _, err := s.DecodeFrom(d, xdr.DecodeDefaultMaxDepth)"
out.puts " _, err := s.DecodeFrom(d, xdr.DecodeDefaultMaxDepth, 0)"
out.puts " return err"
out.puts "}"
out.break
Expand Down Expand Up @@ -836,12 +843,15 @@ def render_top_matter(out)
"errors"
"io"
"fmt"
"unsafe"
"github.com/stellar/go-xdr/xdr3"
)
EOS
out.break
out.puts <<-EOS.strip_heredoc
// Needed since unsafe is not used in all cases
var _ = unsafe.Sizeof(0)
// XdrFilesSHA256 is the SHA256 hashes of source files.
var XdrFilesSHA256 = map[string]string{
#{@output.relative_source_path_sha256_hashes.map(){ |path, hash| %{"#{path}": "#{hash}",} }.join("\n")}
Expand All @@ -856,19 +866,32 @@ def render_top_matter(out)
}
type decoderFrom interface {
DecodeFrom(d *xdr.Decoder, maxDepth uint) (int, error)
DecodeFrom(d *xdr.Decoder, maxDepth uint, maxAllocSize int) (int, error)
}
// Unmarshal reads an xdr element from `r` into `v`.
func Unmarshal(r io.Reader, v interface{}) (int, error) {
return UnmarshalWithMaxAllocSize(r, v, 0)
}
// Unmarshal reads an xdr element from `r` into `v`.
func UnmarshalWithMaxAllocSize(r io.Reader, v interface{}, maxAllocSize int) (int, error) {
if decodable, ok := v.(decoderFrom); ok {
d := xdr.NewDecoder(r)
return decodable.DecodeFrom(d, xdr.DecodeDefaultMaxDepth)
return decodable.DecodeFrom(d, xdr.DecodeDefaultMaxDepth, maxAllocSize)
}
// delegate to xdr package's Unmarshal
return xdr.Unmarshal(r, v)
}
func mergeMaxAllocSizeAndMaxSize(maxAllocSize int, maxSize int) int {
if maxAllocSize > 0 || maxAllocSize < maxSize {
return maxAllocSize
}
return maxSize
}
// Marshal writes an xdr element `v` into `w`.
func Marshal(w io.Writer, v interface{}) (int, error) {
if _, ok := v.(xdrType); ok {
Expand Down
86 changes: 51 additions & 35 deletions spec/output/generator_spec_go/block_comments.x/MyXDR_generated.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -14,49 +14,65 @@ import (
"errors"
"io"
"fmt"
"unsafe"

"github.com/stellar/go-xdr/xdr3"
)

// Needed since unsafe is not used in all cases
var _ = unsafe.Sizeof(0)
// XdrFilesSHA256 is the SHA256 hashes of source files.
var XdrFilesSHA256 = map[string]string{
"spec/fixtures/generator/block_comments.x": "e13131bc4134f38da17b9d5e9f67d2695a69ef98e3ef272833f4c18d0cc88a30",
}

var ErrMaxDecodingDepthReached = errors.New("maximum decoding depth reached")

type xdrType interface {
xdrType()
}

type decoderFrom interface {
DecodeFrom(d *xdr.Decoder, maxDepth uint) (int, error)
}

// Unmarshal reads an xdr element from `r` into `v`.
func Unmarshal(r io.Reader, v interface{}) (int, error) {
if decodable, ok := v.(decoderFrom); ok {
d := xdr.NewDecoder(r)
return decodable.DecodeFrom(d, xdr.DecodeDefaultMaxDepth)
}
// delegate to xdr package's Unmarshal
return xdr.Unmarshal(r, v)
}

// Marshal writes an xdr element `v` into `w`.
func Marshal(w io.Writer, v interface{}) (int, error) {
if _, ok := v.(xdrType); ok {
if bm, ok := v.(encoding.BinaryMarshaler); ok {
b, err := bm.MarshalBinary()
if err != nil {
return 0, err
}
return w.Write(b)
}
}
// delegate to xdr package's Marshal
return xdr.Marshal(w, v)
var ErrMaxDecodingDepthReached = errors.New("maximum decoding depth reached")

type xdrType interface {
xdrType()
}

type decoderFrom interface {
DecodeFrom(d *xdr.Decoder, maxDepth uint, maxAllocSize int) (int, error)
}

// Unmarshal reads an xdr element from `r` into `v`.
func Unmarshal(r io.Reader, v interface{}) (int, error) {
return UnmarshalWithMaxAllocSize(r, v, 0)
}

// Unmarshal reads an xdr element from `r` into `v`.
func UnmarshalWithMaxAllocSize(r io.Reader, v interface{}, maxAllocSize int) (int, error) {
if decodable, ok := v.(decoderFrom); ok {
d := xdr.NewDecoder(r)
return decodable.DecodeFrom(d, xdr.DecodeDefaultMaxDepth, maxAllocSize)
}
// delegate to xdr package's Unmarshal
return xdr.Unmarshal(r, v)
}

func mergeMaxAllocSizeAndMaxSize(maxAllocSize int, maxSize int) int {
if maxAllocSize > 0 || maxAllocSize < maxSize {
return maxAllocSize
}
return maxSize
}


// Marshal writes an xdr element `v` into `w`.
func Marshal(w io.Writer, v interface{}) (int, error) {
if _, ok := v.(xdrType); ok {
if bm, ok := v.(encoding.BinaryMarshaler); ok {
b, err := bm.MarshalBinary()
if err != nil {
return 0, err
}
return w.Write(b)
}
}
// delegate to xdr package's Marshal
return xdr.Marshal(w, v)
}

// AccountFlags is an XDR Enum defines as:
//
Expand Down Expand Up @@ -95,7 +111,7 @@ func (e AccountFlags) EncodeTo(enc *xdr.Encoder) error {
}
var _ decoderFrom = (*AccountFlags)(nil)
// DecodeFrom decodes this value using the Decoder.
func (e *AccountFlags) DecodeFrom(d *xdr.Decoder, maxDepth uint) (int, error) {
func (e *AccountFlags) DecodeFrom(d *xdr.Decoder, maxDepth uint, maxAllocSize int) (int, error) {
if maxDepth == 0 {
return 0, fmt.Errorf("decoding AccountFlags: %w", ErrMaxDecodingDepthReached)
}
Expand All @@ -122,7 +138,7 @@ func (s AccountFlags) MarshalBinary() ([]byte, error) {
func (s *AccountFlags) UnmarshalBinary(inp []byte) error {
r := bytes.NewReader(inp)
d := xdr.NewDecoder(r)
_, err := s.DecodeFrom(d, xdr.DecodeDefaultMaxDepth)
_, err := s.DecodeFrom(d, xdr.DecodeDefaultMaxDepth, 0)
return err
}

Expand Down
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