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notary: avoid changing pooled fallback transaction witnesses

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Forbid Notary service to change the fallback's witnesses in any way.
Fix the problem described in review comment:
https://github.com/nspcc-dev/neo-go/pull/3098#discussion_r1308336339.

Signed-off-by: Anna Shaleva <shaleva.ann@nspcc.ru>
This commit is contained in:
Anna Shaleva 2023-08-29 14:40:51 +03:00
parent b4dff7b040
commit c63289a564
1 changed files with 23 additions and 7 deletions
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30
pkg/services/notary/notary.go
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@ -19,6 +19,7 @@ import (
"github.com/nspcc-dev/neo-go/pkg/io"
"github.com/nspcc-dev/neo-go/pkg/network/payload"
"github.com/nspcc-dev/neo-go/pkg/util"
"github.com/nspcc-dev/neo-go/pkg/util/slice"
"github.com/nspcc-dev/neo-go/pkg/vm"
"github.com/nspcc-dev/neo-go/pkg/vm/opcode"
"github.com/nspcc-dev/neo-go/pkg/wallet"
@ -264,11 +265,8 @@ func (n *Notary) OnNewRequest(payload *payload.P2PNotaryRequest) {
} else {
// Avoid changes in the main transaction witnesses got from the notary request pool to
// keep the pooled tx valid. We will update its copy => the copy's size will be changed.
cp := *payload.MainTransaction
cp.Scripts = make([]transaction.Witness, len(payload.MainTransaction.Scripts))
copy(cp.Scripts, payload.MainTransaction.Scripts)
r = &request{
main: &cp,
main: safeCopy(payload.MainTransaction),
minNotValidBefore: nvbFallback,
}
n.requests[payload.MainTransaction.Hash()] = r
@ -276,9 +274,12 @@ func (n *Notary) OnNewRequest(payload *payload.P2PNotaryRequest) {
if r.witnessInfo == nil && validationErr == nil {
r.witnessInfo = newInfo
}
// Allow modification of a fallback transaction got from the notary request pool.
// It has dummy Notary witness attached => its size won't be changed.
r.fallbacks = append(r.fallbacks, payload.FallbackTransaction)
// Disallow modification of a fallback transaction got from the notary
// request pool. Even though it has dummy Notary witness attached and its
// size won't be changed after finalisation, the witness bytes changes may
// affect the other users of notary pool and cause race. Avoid this by making
// the copy.
r.fallbacks = append(r.fallbacks, safeCopy(payload.FallbackTransaction))
if exists && r.isMainCompleted() || validationErr != nil {
return
}
@ -338,6 +339,21 @@ func (n *Notary) OnNewRequest(payload *payload.P2PNotaryRequest) {
}
}
// safeCopy creates a copy of provided transaction by dereferencing it and creating
// fresh witnesses so that the tx's witnesses may be modified without affecting the
// copy's ones.
func safeCopy(tx *transaction.Transaction) *transaction.Transaction {
cp := *tx
cp.Scripts = make([]transaction.Witness, len(tx.Scripts))
for i := range cp.Scripts {
cp.Scripts[i] = transaction.Witness{
InvocationScript: slice.Copy(tx.Scripts[i].InvocationScript),
VerificationScript: slice.Copy(tx.Scripts[i].VerificationScript),
}
}
return &cp
}
// OnRequestRemoval is a callback which is called after fallback transaction is removed
// from the notary payload pool due to expiration, main tx appliance or any other reason.
func (n *Notary) OnRequestRemoval(pld *payload.P2PNotaryRequest) {