feat(proxy): accept inbound EQL ciphertext payloads - #458
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Signed-off-by: James Sadler <james@cipherstash.com>
Signed-off-by: James Sadler <james@cipherstash.com>
tobyhede
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Aug 20, 2026
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Reviewed the new inbound EQL ciphertext path. One security issue with two exploit paths, one design trade-off to confirm, and one operational gap. Each item was checked against the actual code on this branch and the cipherstash-client 0.42.2 dependency source before being posted here. Two items from an earlier automated pass did not hold up under verification and are not included: the "h" top-level key check is not dead code (it detects SteVec payloads, which carry no top-level c field), and the binary-parameter byte handling in bind.rs does not corrupt data (original bytes stay untouched, and a failed trial parse falls back safely).
See inline comments for details.
Signed-off-by: James Sadler <james@cipherstash.com>
freshtonic
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Aug 20, 2026
Scope the ZeroKMS cipher to CS_DEFAULT_KEYSET_ID whenever a connection has not selected an override. Previously Proxy only checked that the setting existed, then passed no identifier to ScopedCipher and could silently use the client's account default instead. Application-encrypted payloads use the configured keyset explicitly. When the account and configured defaults differ, Proxy derived searchable-encryption metadata with another index key and rejected valid inbound ciphertext during authentication. Preserve connection-level keyset precedence while making the configured fallback effective. Signed-off-by: James Sadler <james@cipherstash.com>
Inbound EQL authentication independently re-encrypts plaintext and compares its searchable-encryption metadata with the supplied payload. Match-index generation does not guarantee a stable ordering for Bloom-filter bit positions, so comparing serialized query operands rejected valid ciphertext whenever equivalent positions were emitted in another order. Compare scalar metadata field by field and normalize Bloom-filter positions before equality. Continue comparing identifiers, exact-match terms, ordered terms, versions, and structured SteVec operands exactly so altered metadata still fails closed. Add a regression test covering reordered equivalent Bloom-filter terms. Signed-off-by: James Sadler <james@cipherstash.com>
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Summary
cipherstash-proxy-integrationTesting
cargo test -p cipherstash-proxy inbound_eql --libcargo test -p cipherstash-proxy --lib(135 passed; one environment-sensitive config test passed when rerun alone)cargo test -p cipherstash-proxy config::tandem::tests::missing_database_config --lib -- --exactcargo clippy -p cipherstash-proxy --all-targets -- -D warningscargo clippy -p cipherstash-proxy-integration -p showcase --all-targets -- -D warningscargo test -p cipherstash-proxy-integration --no-runcargo test -p showcase --no-runcargo fmt --all -- --checkThe runtime integration/showcase cases use the existing credentialed CI tasks. This checkout had no application/ZeroKMS credentials with which to start an isolated current-branch Proxy locally.
Linear: CIP-3822