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Update symtab.go - only calculating offset into runtime.__func.funcda…
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…ta[]

fixes 2 issues that lead to out of bounds indexing. pcdata array may be null and we don't use any of it's values; fix no longer indexes into this array. also we do <= check instead of < when verifying there are enough elements in funcData array.
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@brigadier-general
brigadier-general authored Jun 26, 2024
1 parent 6c347c1 commit 31e5ef1
Showing 1 changed file with 88 additions and 89 deletions.
177 changes: 88 additions & 89 deletions debug/gosym/symtab.go
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Original file line number Diff line number Diff line change
Expand Up @@ -128,69 +128,68 @@ func (s *Sym) BaseName() string {
return s.Name
}


// go v1.16-v1.18
type inlinedCall_v116 struct {
parent int16
funcId uint8
_pad uint8
file int32
line int32
func_ int32
parentPc int32
parent int16
funcId uint8
_pad uint8
file int32
line int32
func_ int32
parentPc int32
}

// go v.1.20+
type inlinedCall_v120 struct {
funcId uint8
_pad [3]uint8
nameOff int32
parentPc int32
startLine int32
funcId uint8
_pad [3]uint8
nameOff int32
parentPc int32
startLine int32
}

const (
MAX_TREE_SIZE = 4096
MAX_TREE_SIZE = 4096
size_inlinedCall_v116 = 20
size_inlinedCall_v120 = 16
FUNCID_MAX = 22 // funcID maximum value
size_inlinedCall_v120 = 16
FUNCID_MAX = 22 // funcID maximum value
)

// An InlinedCall collects information about a function that has been inlined as well as its parent
type InlinedCall struct {
Funcname string
ParentName string
CallingPc uint64
ParentEntry uint64
Data []byte
Funcname string
ParentName string
CallingPc uint64
ParentEntry uint64
Data []byte
}

// A Func collects information about a single function.
type Func struct {
Entry uint64
*Sym
End uint64
Params []*Sym // nil for Go 1.3 and later binaries
Locals []*Sym // nil for Go 1.3 and later binaries
FrameSize int
LineTable *LineTable
FuncData funcData
End uint64
Params []*Sym // nil for Go 1.3 and later binaries
Locals []*Sym // nil for Go 1.3 and later binaries
FrameSize int
LineTable *LineTable
FuncData funcData
InlinedList []InlinedCall
Obj *Obj
Obj *Obj
}

const (
PCDATA_InlTreeIndex = 2
FUNCDATA_InlTree = 3
const (
PCDATA_InlTreeIndex = 2
FUNCDATA_InlTree = 3
)

func (f *Func) HasInline() (uint32, uint32) {
func (f *Func) HasInline() uint32 {
npcdata := int(f.FuncData.Num_pcdata())
nfuncdata := int(f.FuncData.Num_funcdata())
nfuncdata := int(f.FuncData.Num_funcdata())

// check the relevant indices exist
if (npcdata < PCDATA_InlTreeIndex) && (nfuncdata < FUNCDATA_InlTree) {
return 0, 0
// check the relevant index exists
if nfuncdata <= FUNCDATA_InlTree {
return 0xffff
}

// get the size of runtime_func actual fields
Expand All @@ -199,35 +198,35 @@ func (f *Func) HasInline() (uint32, uint32) {
sz0 = 4
}

func_hdr_size := sz0 + (4*10) // sz of first elt + size of remaining elts
pcdata_size := 4 * npcdata // elts in pcdata[npcdata] are 4 bytes each
funcdata_size := 4 * nfuncdata // ^ditto

func_pseudofields := f.FuncData.data[func_hdr_size:] // chop off actual fields
pcdata_raw := func_pseudofields[:pcdata_size] // isolate just the pcdata table bytes
funcdata_raw := func_pseudofields[pcdata_size:] // ^ditto for funcdata table bytes
// calculate where funcdata array begins
func_hdr_size := int(sz0) + (4 * 10) // sz of first elt + size of remaining elts
pcdata_size := 4 * npcdata // elts in pcdata[npcdata] are 4 bytes each
funcdata_offset := func_hdr_size + pcdata_size

// isolate the funcdata array
funcdata_size := 4 * nfuncdata
funcdata_raw := f.FuncData.data[funcdata_offset:(funcdata_offset + funcdata_size)]
if len(funcdata_raw) != funcdata_size {
fmt.Errorf("wanted %d bytes for uint32_t funcdata[nfuncdata], got %d\n", funcdata_size, len(funcdata_raw))
return 0,0
fmt.Printf("wanted %d bytes for uint32_t funcdata[nfuncdata], got %d\n", funcdata_size, len(funcdata_raw))
return 0xffff
}

// get the actual inline offsets
pcdata_InlIndex := f.LineTable.Binary.Uint32(pcdata_raw[4*PCDATA_InlTreeIndex:])
// get the actual inline data value
funcdata_InlTree := f.LineTable.Binary.Uint32(funcdata_raw[4*FUNCDATA_InlTree:])
// check if these indices are ^uint32(0)
if pcdata_InlIndex == ^uint32(0) || funcdata_InlTree == ^uint32(0) {
return 0, 0

// check if the value is valid
if funcdata_InlTree == ^uint32(0) {
return 0xffff
}
return pcdata_InlIndex, funcdata_InlTree

return funcdata_InlTree
}

func isValidFuncID(data []byte) bool {
// TODO -- currently only accepts "FuncIDNormal"
// We may want to include other types.
if data[0] != 0 {

// TODO -- currently only accepts "FuncIDNormal"
// We may want to include other types.
if data[0] != 0 {
return false
}

Expand All @@ -238,43 +237,43 @@ func isValidFuncID(data []byte) bool {
}
i += 1
}

return true
}

// validate that calling PC falls within calling function
func isValidPC(data []byte, f *Func) (bool, int32) {
var pc int32
var pc_address uint64
var pc int32
var pc_address uint64

// convert bytes to int32
// TODO -- see isValidFuncName()
err := binary.Read(bytes.NewReader(data), binary.LittleEndian, &pc)
if err != nil {
fmt.Println(err)
return false, -1
return false, -1
}
pc_address = uint64(pc) + f.Entry
if (pc_address <= f.End ) && (pc_address >= f.Entry) {
if (pc_address <= f.End) && (pc_address >= f.Entry) {
return true, pc
}
}

return false, -1
}

// TODO -- pull out binary converter to its own func for reuse
// TODO -- check for little vs big endian
func isValidFuncName(data []byte, f *Func) (bool, string) {
var nameOff int32
var nameOff int32

err := binary.Read(bytes.NewReader(data), binary.LittleEndian, &nameOff)
if err != nil {
fmt.Println(err)
return false, ""
}

// check that name offset falls within func name table boundaries
funcNameTable := f.LineTable.funcnametab
funcNameTable := f.LineTable.funcnametab
if nameOff < int32(len(funcNameTable)) {
i := nameOff
for i < int32(len(funcNameTable)) {
Expand All @@ -283,10 +282,10 @@ func isValidFuncName(data []byte, f *Func) (bool, string) {
break
}
i += 1
}
}

name := string(funcNameTable[nameOff : i ])
return true, name
name := string(funcNameTable[nameOff:i])
return true, name
}
return false, ""
}
Expand All @@ -302,33 +301,33 @@ func (f *Func) iterateInline_v120(tree []byte) []InlinedCall {

// check there are enough bytes for an inlinedCall struct
off := 0
// iterate until we hit invalid data
// iterate until we hit invalid data
// that indicates we've read this function's entire inline tree
for (len(tree) - off >= size_inlinedCall_v120) {
for len(tree)-off >= size_inlinedCall_v120 {
// get elt bytes
elt_raw := tree[ off : off+size_inlinedCall_v120]
elt_raw := tree[off : off+size_inlinedCall_v120]

// verify funcId and padding look normal
if !isValidFuncID(elt_raw[ : 4]) {
if !isValidFuncID(elt_raw[:4]) {
break
}
// verify calling PC exists within parent func bounds
is_valid_pc, pc := isValidPC(elt_raw[8:12], f)
is_valid_pc, pc := isValidPC(elt_raw[8:12], f)
if !is_valid_pc {
break
}
// resolve name
// resolve name
is_valid_fname, fname := isValidFuncName(elt_raw[4:8], f)
if !is_valid_fname {
break
}
}
// create InlinedCall object
inlineList = append(inlineList, InlinedCall {
Funcname: fname,
ParentName: f.Name,
CallingPc: uint64(pc),
ParentEntry: f.Entry,
Data: elt_raw,
inlineList = append(inlineList, InlinedCall{
Funcname: fname,
ParentName: f.Name,
CallingPc: uint64(pc),
ParentEntry: f.Entry,
Data: elt_raw,
})
// add obj to InlineList
off = off + size_inlinedCall_v120
Expand All @@ -338,7 +337,7 @@ func (f *Func) iterateInline_v120(tree []byte) []InlinedCall {

// return array of inlined functions inside f or nil
func (f *Func) GetInlinedCalls(data []byte) {
var inlList []InlinedCall
var inlList []InlinedCall

// get size of inlined struct based on version
if f.LineTable.Version >= ver118 {
Expand All @@ -349,12 +348,12 @@ func (f *Func) GetInlinedCalls(data []byte) {

for _, elt := range inlList {
f.InlinedList = append(f.InlinedList, InlinedCall{
Funcname: elt.Funcname,
ParentName: elt.ParentName,
CallingPc: elt.CallingPc,
ParentEntry: elt.ParentEntry,
Data: elt.Data,
})
Funcname: elt.Funcname,
ParentName: elt.ParentName,
CallingPc: elt.CallingPc,
ParentEntry: elt.ParentEntry,
Data: elt.Data,
})
}
}

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