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authorFelföldi Zsolt <zsfelfoldi@gmail.com>2018-06-05 15:23:00 +0800
committerPéter Szilágyi <peterke@gmail.com>2018-06-05 15:23:00 +0800
commita5237a27eaf81946a3edb4fafe13ed6359d119e4 (patch)
tree72108de3c3096961554d8141ed97292fa157e524 /les
parent7a22e89080b2be624c2659c8ea9dc34820400ffd (diff)
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les: add Skip overflow check to GetBlockHeadersMsg handler (#16891)
Diffstat (limited to 'les')
-rw-r--r--les/handler.go25
1 files changed, 18 insertions, 7 deletions
diff --git a/les/handler.go b/les/handler.go
index 22899eb1b..1b6916578 100644
--- a/les/handler.go
+++ b/les/handler.go
@@ -19,6 +19,7 @@ package les
import (
"encoding/binary"
+ "encoding/json"
"errors"
"fmt"
"math/big"
@@ -441,7 +442,7 @@ func (pm *ProtocolManager) handleMsg(p *peer) error {
// Advance to the next header of the query
switch {
- case query.Origin.Hash != (common.Hash{}) && query.Reverse:
+ case hashMode && query.Reverse:
// Hash based traversal towards the genesis block
for i := 0; i < int(query.Skip)+1; i++ {
if header := pm.blockchain.GetHeader(query.Origin.Hash, number); header != nil {
@@ -452,16 +453,26 @@ func (pm *ProtocolManager) handleMsg(p *peer) error {
break
}
}
- case query.Origin.Hash != (common.Hash{}) && !query.Reverse:
+ case hashMode && !query.Reverse:
// Hash based traversal towards the leaf block
- if header := pm.blockchain.GetHeaderByNumber(origin.Number.Uint64() + query.Skip + 1); header != nil {
- if pm.blockchain.GetBlockHashesFromHash(header.Hash(), query.Skip+1)[query.Skip] == query.Origin.Hash {
- query.Origin.Hash = header.Hash()
+ var (
+ current = origin.Number.Uint64()
+ next = current + query.Skip + 1
+ )
+ if next <= current {
+ infos, _ := json.MarshalIndent(p.Peer.Info(), "", " ")
+ p.Log().Warn("GetBlockHeaders skip overflow attack", "current", current, "skip", query.Skip, "next", next, "attacker", infos)
+ unknown = true
+ } else {
+ if header := pm.blockchain.GetHeaderByNumber(next); header != nil {
+ if pm.blockchain.GetBlockHashesFromHash(header.Hash(), query.Skip+1)[query.Skip] == query.Origin.Hash {
+ query.Origin.Hash = header.Hash()
+ } else {
+ unknown = true
+ }
} else {
unknown = true
}
- } else {
- unknown = true
}
case query.Reverse:
// Number based traversal towards the genesis block