RUSTSEC-2022-0093: Double Public Key Signing Function Oracle Attack on `ed25519-dalek`
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Double Public Key Signing Function Oracle Attack on
ed25519-dalek
Details | |
---|---|
Package | ed25519-dalek |
Version | 1.0.1 |
URL | https://github.com/MystenLabs/ed25519-unsafe-libs |
Date | 2022-06-11 |
Patched versions | >=2 |
Versions of ed25519-dalek
prior to v2.0 model private and public keys as
separate types which can be assembled into a Keypair
, and also provide APIs
for serializing and deserializing 64-byte private/public keypairs.
Such APIs and serializations are inherently unsafe as the public key is one of
the inputs used in the deterministic computation of the S
part of the signature,
but not in the R
value. An adversary could somehow use the signing function as
an oracle that allows arbitrary public keys as input can obtain two signatures
for the same message sharing the same R
and only differ on the S
part.
Unfortunately, when this happens, one can easily extract the private key.
Revised public APIs in v2.0 of ed25519-dalek
do NOT allow a decoupled
private/public keypair as signing input, except as part of specially labeled
"hazmat" APIs which are clearly labeled as being dangerous if misused.
See advisory page for additional details.