Transport padding (s4) crashed the whole process with
"index out of range" in RoutineSequentialSender on the first data
packet: InputPacket/InputPackets sized elem.buffer without headroom
for the in-buffer right-shift that prepends the random prefix.
- send.go: reserve paddings.transport in both injection-path
allocLength computations; replace the manual backward byte loop
with an overlap-safe copy; defensively grow the buffer (pool-backed)
if it still lacks headroom, dropping packets that cannot fit a
single WG message instead of overrunning.
- receive.go: drop the rxBytes/timers block duplicated by the AWG
re-graft (rx accounting was doubled, keepKeyFreshReceiving fired
twice per batch).
- send.go: swap jmin/jmax when configured inverted (UAPI validates
the fields only individually; a swapped pair panicked rand.Int
with a non-positive bound on the first handshake).
- obf*.go: bound obfuscator length args to [0, MaxMessageSize]
(negative panicked slice bounds, huge ones OOMed the handshake).
- magic-header.go: widen to int64 before end-start+1 so a full-range
header cannot wrap to a zero rand.Int bound.
Tests: transport_padding_test.go reproduces the on-device crash
byte-for-byte (red on the previous commit, green now) across both
injection paths and the tun path; obf_guards_test.go pins the
config-value guards.
Rebase of the AWG obf graft (was e5feca7 on v0.0.3) onto v0.0.5
(2c27bbf4f9, 'Add L3 forwarding support'). 15 of 16 graft files
applied clean via 3-way; only send.go conflicted, on a single line
(upstream queuedOutboundPackets backpressure decrement vs a graft
blank line — took upstream).
Key invariant preserved: MessageEncapsulatingTransportSize=0 (graft
zeroes the sagernet encapsulating headroom; AWG obfuscation composes
the prefix itself via SendBuffers, not Bind.Send prepend). Upstream's
InputPacket/InputPackets and the new size-based outbound buffer pool
(GetOutboundBuffer/PutOutboundBuffer) are taken verbatim; the graft's
RoutineEncryption (header at buffer start) and transport-padding shift
in RoutineSequentialSender re-woven around them.
Builds clean on linux/android/windows/darwin (device/conn/tun).
