Prevent savedata corruption and denial-of-service by adding four layers
of protection to the save pipeline:
- Bounded decompression (nullcomp.DecompressWithLimit): caps output size
to prevent OOM from crafted payloads that expand to exhaust memory
- Bounds-checked delta patching (deltacomp.ApplyDataDiffWithLimit):
validates offsets before writing, returns errors for negative offsets,
truncated patches, and oversized output; ApplyDataDiff now returns
original data on error instead of partial corruption
- Size limits on save handlers: rejects compressed payloads >512KB and
decompressed data >1MB before processing; applied to main savedata,
platedata, and platebox diff paths
- Rotating savedata backups: 3 slots per character with 30-minute
interval, snapshots the previous state before overwriting, backed by
new savedata_backups table (migration 0007)
Replace all fmt.Printf/Println and log.Printf/Fatal with structured
zap.Logger calls to eliminate inconsistent logging (anti-pattern #12).
- network/crypt_conn: inject logger via NewCryptConn, replace 6 fmt calls
- signserver/session: use existing s.logger for debug packet dumps
- entranceserver: use s.logger for inbound/outbound debug logging
- api/utils: accept logger param in verifyPath, replace fmt.Println
- api/endpoints: use s.logger for screenshot path diagnostics
- config: replace log.Fatal with error return in getOutboundIP4
- deltacomp: replace log.Printf with zap.L() global logger
Add package-level documentation (doc.go) to all 22 first-party
packages and godoc comments to ~150 previously undocumented
exported symbols across common/, network/, and server/.
Move time utilities (TimeAdjusted, TimeMidnight, TimeWeekStart, TimeWeekNext,
TimeGameAbsolute) from channelserver into common/gametime to break the
inappropriate dependency where signserver, entranceserver, and api imported
the 38K-line channelserver package just for time functions.
Replace all fmt.Printf debug logging in sys_session.go and handlers_object.go
with structured zap logging for consistent observability.
