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lib/model: Verify request content against weak (and possibly strong) hash (#4767)

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This commit is contained in:
Audrius Butkevicius
2018-05-05 09:24:44 +01:00
committed by Jakob Borg
parent 678c80ffe4
commit ef0dcea6a4
27 changed files with 518 additions and 454 deletions
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71
lib/model/rwfolder.go
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@@ -1186,36 +1186,32 @@ func (f *sendReceiveFolder) copierRoutine(in <-chan copyBlocksState, pullChan ch
var file fs.File
var weakHashFinder *weakhash.Finder
if weakhash.Enabled {
blocksPercentChanged := 0
if tot := len(state.file.Blocks); tot > 0 {
blocksPercentChanged = (tot - state.have) * 100 / tot
blocksPercentChanged := 0
if tot := len(state.file.Blocks); tot > 0 {
blocksPercentChanged = (tot - state.have) * 100 / tot
}
if blocksPercentChanged >= f.WeakHashThresholdPct {
hashesToFind := make([]uint32, 0, len(state.blocks))
for _, block := range state.blocks {
if block.WeakHash != 0 {
hashesToFind = append(hashesToFind, block.WeakHash)
}
}
if blocksPercentChanged >= f.WeakHashThresholdPct {
hashesToFind := make([]uint32, 0, len(state.blocks))
for _, block := range state.blocks {
if block.WeakHash != 0 {
hashesToFind = append(hashesToFind, block.WeakHash)
if len(hashesToFind) > 0 {
file, err = f.fs.Open(state.file.Name)
if err == nil {
weakHashFinder, err = weakhash.NewFinder(file, int(state.file.BlockSize()), hashesToFind)
if err != nil {
l.Debugln("weak hasher", err)
}
}
if len(hashesToFind) > 0 {
file, err = f.fs.Open(state.file.Name)
if err == nil {
weakHashFinder, err = weakhash.NewFinder(file, int(state.file.BlockSize()), hashesToFind)
if err != nil {
l.Debugln("weak hasher", err)
}
}
} else {
l.Debugf("not weak hashing %s. file did not contain any weak hashes", state.file.Name)
}
} else {
l.Debugf("not weak hashing %s. not enough changed %.02f < %d", state.file.Name, blocksPercentChanged, f.WeakHashThresholdPct)
l.Debugf("not weak hashing %s. file did not contain any weak hashes", state.file.Name)
}
} else {
l.Debugf("not weak hashing %s. weak hashing disabled", state.file.Name)
l.Debugf("not weak hashing %s. not enough changed %.02f < %d", state.file.Name, blocksPercentChanged, f.WeakHashThresholdPct)
}
for _, block := range state.blocks {
@@ -1239,7 +1235,7 @@ func (f *sendReceiveFolder) copierRoutine(in <-chan copyBlocksState, pullChan ch
}
found, err := weakHashFinder.Iterate(block.WeakHash, buf, func(offset int64) bool {
if _, err := verifyBuffer(buf, block); err != nil {
if verifyBuffer(buf, block) != nil {
return true
}
@@ -1274,17 +1270,8 @@ func (f *sendReceiveFolder) copierRoutine(in <-chan copyBlocksState, pullChan ch
return false
}
hash, err := verifyBuffer(buf, block)
if err != nil {
if hash != nil {
l.Debugf("Finder block mismatch in %s:%s:%d expected %q got %q", folder, path, index, block.Hash, hash)
err = f.model.finder.Fix(folder, path, index, block.Hash, hash)
if err != nil {
l.Warnln("finder fix:", err)
}
} else {
l.Debugln("Finder failed to verify buffer", err)
}
if err := verifyBuffer(buf, block); err != nil {
l.Debugln("Finder failed to verify buffer", err)
return false
}
@@ -1324,22 +1311,22 @@ func (f *sendReceiveFolder) copierRoutine(in <-chan copyBlocksState, pullChan ch
}
}
func verifyBuffer(buf []byte, block protocol.BlockInfo) ([]byte, error) {
func verifyBuffer(buf []byte, block protocol.BlockInfo) error {
if len(buf) != int(block.Size) {
return nil, fmt.Errorf("length mismatch %d != %d", len(buf), block.Size)
return fmt.Errorf("length mismatch %d != %d", len(buf), block.Size)
}
hf := sha256.New()
_, err := hf.Write(buf)
if err != nil {
return nil, err
return err
}
hash := hf.Sum(nil)
if !bytes.Equal(hash, block.Hash) {
return hash, fmt.Errorf("hash mismatch %x != %x", hash, block.Hash)
return fmt.Errorf("hash mismatch %x != %x", hash, block.Hash)
}
return hash, nil
return nil
}
func (f *sendReceiveFolder) pullerRoutine(in <-chan pullBlockState, out chan<- *sharedPullerState) {
@@ -1411,7 +1398,7 @@ func (f *sendReceiveFolder) pullBlock(state pullBlockState, out chan<- *sharedPu
// Fetch the block, while marking the selected device as in use so that
// leastBusy can select another device when someone else asks.
activity.using(selected)
buf, lastError := f.model.requestGlobal(selected.ID, f.folderID, state.file.Name, state.block.Offset, int(state.block.Size), state.block.Hash, selected.FromTemporary)
buf, lastError := f.model.requestGlobal(selected.ID, f.folderID, state.file.Name, state.block.Offset, int(state.block.Size), state.block.Hash, state.block.WeakHash, selected.FromTemporary)
activity.done(selected)
if lastError != nil {
l.Debugln("request:", f.folderID, state.file.Name, state.block.Offset, state.block.Size, "returned error:", lastError)
@@ -1420,7 +1407,7 @@ func (f *sendReceiveFolder) pullBlock(state pullBlockState, out chan<- *sharedPu
// Verify that the received block matches the desired hash, if not
// try pulling it from another device.
_, lastError = verifyBuffer(buf, state.block)
lastError = verifyBuffer(buf, state.block)
if lastError != nil {
l.Debugln("request:", f.folderID, state.file.Name, state.block.Offset, state.block.Size, "hash mismatch")
continue