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Fix attempt logic in moduledata scan to ignore erroneous early hits a…
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…nd add them to the ignorelist, resolves #50
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@stepheneckels
stepheneckels committed Feb 23, 2024
1 parent 0860a1b commit 76f8f7c
Showing 1 changed file with 51 additions and 44 deletions.
95 changes: 51 additions & 44 deletions objfile/objfile.go
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Expand Up @@ -277,10 +277,17 @@ func (e *Entry) ModuleDataTable(pclntabVA uint64, runtimeVersion string, version
runtimeVersion = parts[0] + "." + parts[1]
}

var moduleDataCandidate *ModuleDataCandidate = nil

const maxattempts = 5
var ignorelist []uint64
for i := 0; i < maxattempts; i++ {
moduleDataCandidate, err := e.raw.moduledata_scan(pclntabVA, is64bit, littleendian, ignorelist)
// we're trying again, ignore the previous candidate
if moduleDataCandidate != nil {
ignorelist = append(ignorelist, moduleDataCandidate.ModuledataVA)
}

moduleDataCandidate, err = e.raw.moduledata_scan(pclntabVA, is64bit, littleendian, ignorelist)
if err != nil {
continue
}
Expand All @@ -295,18 +302,18 @@ func (e *Entry) ModuleDataTable(pclntabVA uint64, runtimeVersion string, version
var module ModuleData121_64
err := module.parse(moduleDataCandidate.Moduledata, littleendian)
if err != nil {
return 0, nil, err
continue
}

var firstFunc FuncTab118
ftab_raw, err := e.raw.read_memory(uint64(module.Ftab.Data), uint64(unsafe.Sizeof(firstFunc)))
if err != nil {
return 0, nil, err
continue
}

err = firstFunc.parse(ftab_raw, littleendian)
if err != nil {
return 0, nil, err
continue
}

// prevent loop on invalid modules with bogus length
Expand Down Expand Up @@ -349,18 +356,18 @@ func (e *Entry) ModuleDataTable(pclntabVA uint64, runtimeVersion string, version
var module ModuleData121_32
err := module.parse(moduleDataCandidate.Moduledata, littleendian)
if err != nil {
return 0, nil, err
continue
}

var firstFunc FuncTab118
ftab_raw, err := e.raw.read_memory(uint64(module.Ftab.Data), uint64(unsafe.Sizeof(firstFunc)))
if err != nil {
return 0, nil, err
continue
}

err = firstFunc.parse(ftab_raw, littleendian)
if err != nil {
return 0, nil, err
continue
}

// prevent loop on invalid modules with bogus length
Expand Down Expand Up @@ -410,18 +417,18 @@ func (e *Entry) ModuleDataTable(pclntabVA uint64, runtimeVersion string, version
var module ModuleData120_64
err := module.parse(moduleDataCandidate.Moduledata, littleendian)
if err != nil {
return 0, nil, err
continue
}

var firstFunc FuncTab118
ftab_raw, err := e.raw.read_memory(uint64(module.Ftab.Data), uint64(unsafe.Sizeof(firstFunc)))
if err != nil {
return 0, nil, err
continue
}

err = firstFunc.parse(ftab_raw, littleendian)
if err != nil {
return 0, nil, err
continue
}

// prevent loop on invalid modules with bogus length
Expand Down Expand Up @@ -464,18 +471,18 @@ func (e *Entry) ModuleDataTable(pclntabVA uint64, runtimeVersion string, version
var module ModuleData120_32
err := module.parse(moduleDataCandidate.Moduledata, littleendian)
if err != nil {
return 0, nil, err
continue
}

var firstFunc FuncTab118
ftab_raw, err := e.raw.read_memory(uint64(module.Ftab.Data), uint64(unsafe.Sizeof(firstFunc)))
if err != nil {
return 0, nil, err
continue
}

err = firstFunc.parse(ftab_raw, littleendian)
if err != nil {
return 0, nil, err
continue
}

// prevent loop on invalid modules with bogus length
Expand Down Expand Up @@ -525,18 +532,18 @@ func (e *Entry) ModuleDataTable(pclntabVA uint64, runtimeVersion string, version
var module ModuleData118_64
err := module.parse(moduleDataCandidate.Moduledata, littleendian)
if err != nil {
return 0, nil, err
continue
}

var firstFunc FuncTab118
ftab_raw, err := e.raw.read_memory(uint64(module.Ftab.Data), uint64(unsafe.Sizeof(firstFunc)))
if err != nil {
return 0, nil, err
continue
}

err = firstFunc.parse(ftab_raw, littleendian)
if err != nil {
return 0, nil, err
continue
}

// prevent loop on invalid modules with bogus length
Expand Down Expand Up @@ -579,18 +586,18 @@ func (e *Entry) ModuleDataTable(pclntabVA uint64, runtimeVersion string, version
var module ModuleData118_32
err := module.parse(moduleDataCandidate.Moduledata, littleendian)
if err != nil {
return 0, nil, err
continue
}

var firstFunc FuncTab118
ftab_raw, err := e.raw.read_memory(uint64(module.Ftab.Data), uint64(unsafe.Sizeof(firstFunc)))
if err != nil {
return 0, nil, err
continue
}

err = firstFunc.parse(ftab_raw, littleendian)
if err != nil {
return 0, nil, err
continue
}

// prevent loop on invalid modules with bogus length
Expand Down Expand Up @@ -640,18 +647,18 @@ func (e *Entry) ModuleDataTable(pclntabVA uint64, runtimeVersion string, version
var module ModuleData116_64
err := module.parse(moduleDataCandidate.Moduledata, littleendian)
if err != nil {
return 0, nil, err
continue
}

var firstFunc FuncTab12_116_64
ftab_raw, err := e.raw.read_memory(uint64(module.Ftab.Data), uint64(unsafe.Sizeof(firstFunc)))
if err != nil {
return 0, nil, err
continue
}

err = firstFunc.parse(ftab_raw, littleendian)
if err != nil {
return 0, nil, err
continue
}

// functab's first function should equal the minpc value of moduledata. If not, parse failed, or we found wrong moduledata
Expand All @@ -672,18 +679,18 @@ func (e *Entry) ModuleDataTable(pclntabVA uint64, runtimeVersion string, version
var module ModuleData116_32
err := module.parse(moduleDataCandidate.Moduledata, littleendian)
if err != nil {
return 0, nil, err
continue
}

var firstFunc FuncTab12_116_32
ftab_raw, err := e.raw.read_memory(uint64(module.Ftab.Data), uint64(unsafe.Sizeof(firstFunc)))
if err != nil {
return 0, nil, err
continue
}

err = firstFunc.parse(ftab_raw, littleendian)
if err != nil {
return 0, nil, err
continue
}

// functab's first function should equal the minpc value of moduledata. If not, parse failed, or we found wrong moduledata
Expand Down Expand Up @@ -717,18 +724,18 @@ func (e *Entry) ModuleDataTable(pclntabVA uint64, runtimeVersion string, version
var module ModuleData12_r15_r16_64
err := module.parse(moduleDataCandidate.Moduledata, littleendian)
if err != nil {
return 0, nil, err
continue
}

var firstFunc FuncTab12_116_64
ftab_raw, err := e.raw.read_memory(uint64(module.Ftab.Data), uint64(unsafe.Sizeof(firstFunc)))
if err != nil {
return 0, nil, err
continue
}

err = firstFunc.parse(ftab_raw, littleendian)
if err != nil {
return 0, nil, err
continue
}

// functab's first function should equal the minpc value of moduledata. If not, parse failed, or we found wrong moduledata
Expand All @@ -748,18 +755,18 @@ func (e *Entry) ModuleDataTable(pclntabVA uint64, runtimeVersion string, version
var module ModuleData12_r15_r16_32
err := module.parse(moduleDataCandidate.Moduledata, littleendian)
if err != nil {
return 0, nil, err
continue
}

var firstFunc FuncTab12_116_32
ftab_raw, err := e.raw.read_memory(uint64(module.Ftab.Data), uint64(unsafe.Sizeof(firstFunc)))
if err != nil {
return 0, nil, err
continue
}

err = firstFunc.parse(ftab_raw, littleendian)
if err != nil {
return 0, nil, err
continue
}

// functab's first function should equal the minpc value of moduledata. If not, parse failed, or we found wrong moduledata
Expand All @@ -781,18 +788,18 @@ func (e *Entry) ModuleDataTable(pclntabVA uint64, runtimeVersion string, version
var module ModuleData12_r17_64
err := module.parse(moduleDataCandidate.Moduledata, littleendian)
if err != nil {
return 0, nil, err
continue
}

var firstFunc FuncTab12_116_64
ftab_raw, err := e.raw.read_memory(uint64(module.Ftab.Data), uint64(unsafe.Sizeof(firstFunc)))
if err != nil {
return 0, nil, err
continue
}

err = firstFunc.parse(ftab_raw, littleendian)
if err != nil {
return 0, nil, err
continue
}

// functab's first function should equal the minpc value of moduledata. If not, parse failed, or we found wrong moduledata
Expand All @@ -815,18 +822,18 @@ func (e *Entry) ModuleDataTable(pclntabVA uint64, runtimeVersion string, version
var module ModuleData12_r17_32
err := module.parse(moduleDataCandidate.Moduledata, littleendian)
if err != nil {
return 0, nil, err
continue
}

var firstFunc FuncTab12_116_32
ftab_raw, err := e.raw.read_memory(uint64(module.Ftab.Data), uint64(unsafe.Sizeof(firstFunc)))
if err != nil {
return 0, nil, err
continue
}

err = firstFunc.parse(ftab_raw, littleendian)
if err != nil {
return 0, nil, err
continue
}

// functab's first function should equal the minpc value of moduledata. If not, parse failed, or we found wrong moduledata
Expand Down Expand Up @@ -868,18 +875,18 @@ func (e *Entry) ModuleDataTable(pclntabVA uint64, runtimeVersion string, version
var module ModuleData12_64
err := module.parse(moduleDataCandidate.Moduledata, littleendian)
if err != nil {
return 0, nil, err
continue
}

var firstFunc FuncTab12_116_64
ftab_raw, err := e.raw.read_memory(uint64(module.Ftab.Data), uint64(unsafe.Sizeof(firstFunc)))
if err != nil {
return 0, nil, err
continue
}

err = firstFunc.parse(ftab_raw, littleendian)
if err != nil {
return 0, nil, err
continue
}

// functab's first function should equal the minpc value of moduledata. If not, parse failed, or we found wrong moduledata
Expand All @@ -900,18 +907,18 @@ func (e *Entry) ModuleDataTable(pclntabVA uint64, runtimeVersion string, version
var module ModuleData12_32
err := module.parse(moduleDataCandidate.Moduledata, littleendian)
if err != nil {
return 0, nil, err
continue
}

var firstFunc FuncTab12_116_32
ftab_raw, err := e.raw.read_memory(uint64(module.Ftab.Data), uint64(unsafe.Sizeof(firstFunc)))
if err != nil {
return 0, nil, err
continue
}

err = firstFunc.parse(ftab_raw, littleendian)
if err != nil {
return 0, nil, err
continue
}

// functab's first function should equal the minpc value of moduledata. If not, parse failed, or we found wrong moduledata
Expand All @@ -938,7 +945,7 @@ func (e *Entry) ModuleDataTable(pclntabVA uint64, runtimeVersion string, version
}
}

// should only happen if all scans and validation fail
// should only happen if all scan attempts and validation fail
return 0, nil, fmt.Errorf("moduledata not found")
}

Expand Down

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