On 32-bit architectures (e.g. ARM7), int is 32 bits wide.
Casting a uint32 hash value to int can overflow, producing a
negative number. Go's modulo operator preserves the sign, so
the channel index can become -1, causing a panic.
Perform the modulo in uint32 space before indexing to ensure
the result is always non-negative.
Fixes#413
Instead of a separate cert_probe.go that duplicates the scout's TLS
connection logic, measure the cert chain size directly from the same
HTTPS connections the scout already makes.
Changes:
- Extend ScoutConnResult with payloadLen field
- Add Write interception to ScoutConn for handshake boundary detection
- Scout.learn() now computes cert size (sum of ApplicationData between
CCS and first client Write) alongside inter-record durations
- Ganger aggregates cert sizes across raids and exposes NoiseParams()
via atomic pointer for lock-free reads from proxy goroutines
- Proxy reads NoiseParams from Ganger on each handshake instead of
probing at startup
- Remove cert_probe.go, disk cache, and related config options
(noise-cache-path, noise-cache-ttl, noise-probe-count)
Falls back to legacy 2500-4700 range until the first scout raid
completes (typically within 1-2 seconds of startup).
The hardcoded noise range (2500-4700 bytes) in the FakeTLS ServerHello
does not match the real certificate chain sizes of many popular fronting
domains (e.g., dl.google.com ≈ 6480 bytes, microsoft.com ≈ 13004 bytes).
This makes the proxy detectable by DPI systems that compare the
ApplicationData size with the real cert chain size for the SNI domain.
On startup, probe the fronting domain's actual TLS handshake size and
use the measured value ± jitter instead of the static range. Falls back
to the legacy 2500-4700 range if the probe fails.
Also adds optional caching of probe results between restarts
(noise-cache-path, noise-cache-ttl) and a configurable probe count
(noise-probe-count) under [defense.doppelganger].
Closes#408
Alexey Dolotov