mirror of
https://github.com/jetkvm/kvm.git
synced 2026-05-21 05:20:35 +00:00
Alex Howells
ea5f0e5f4a
parseAndValidateKeyring validates that at least one entity in a
fetched keyring matches the pinned root key fingerprint
(rootKeyFingerprint, gpg.go:21). On match, it returns the entire
keyring — including any additional entities the keyserver included
in its response.
This is a problem because openpgp.CheckDetachedSignature iterates
every key in the provided keyring and accepts a signature from any
of them. A compromised or malicious keyserver could return a
response containing the legitimate JetKVM release key (satisfying
the fingerprint check) alongside an attacker-controlled key. A
binary signed with the attacker key would then pass verification
in both VerifySignature and VerifySignatureFromFile, since both
pass the cached keyring directly to CheckDetachedSignature.
The fix is a single-line change: return openpgp.EntityList{entity}
instead of the full keyring when the fingerprint matches. This
ensures only the trusted key is ever used for signature verification
regardless of what a keyserver returns.
TestParseAndValidateKeyring_FiltersRogueKeys exercises this by
constructing a two-entity armored keyring (trusted + rogue),
passing it through parseAndValidateKeyring, asserting the returned
keyring contains exactly one entity with the correct fingerprint,
and confirming that CheckDetachedSignature rejects a signature
produced by the rogue key.
Reported-by: equinox0815
Signed-off-by: Alex Howells <alex@howells.me>