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Add additional checks to key_gen/sign

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There is the ability to cause state bloat by flooding Tributary.
KeyGen/Sign specifically shouldn't allow bloat since we check the
commitments/preprocesses/shares for validity. Accordingly, any invalid data
(such as bloat) should be detected.

It was posssible to place bloat after the valid data. Doing so would be
considered a valid KeyGen/Sign message, yet could add up to 50k kB per sign.
This commit is contained in:
Luke Parker
2023-04-20 05:22:59 -04:00
parent 8041a0d845
commit 8b5eaa8092
2 changed files with 26 additions and 4 deletions
Download Patch File Download Diff File Expand all files Collapse all files

18
processor/src/signer.rs
View File

@@ -374,9 +374,14 @@ impl<C: Coin, D: Db> Signer<C, D> {
let preprocesses = match preprocesses
.drain()
.map(|(l, preprocess)| {
machine
.read_preprocess::<&[u8]>(&mut preprocess.as_ref())
.map(|preprocess| (l, preprocess))
let mut preprocess_ref = preprocess.as_ref();
let res = machine
.read_preprocess::<&[u8]>(&mut preprocess_ref)
.map(|preprocess| (l, preprocess));
if !preprocess_ref.is_empty() {
todo!("malicious signer: extra bytes");
}
res
})
.collect::<Result<_, _>>()
{
@@ -424,7 +429,12 @@ impl<C: Coin, D: Db> Signer<C, D> {
let shares = match shares
.drain()
.map(|(l, share)| {
machine.read_share::<&[u8]>(&mut share.as_ref()).map(|share| (l, share))
let mut share_ref = share.as_ref();
let res = machine.read_share::<&[u8]>(&mut share_ref).map(|share| (l, share));
if !share_ref.is_empty() {
todo!("malicious signer: extra bytes");
}
res
})
.collect::<Result<_, _>>()
{