benjamin
72f4661bdc
- Multi-stage Dockerfile: discover patterns from PMS binary (capstone), compile .so with zig (musl), layer onto lscr.io/linuxserver/plex - Uses LD_PRELOAD instead of patchelf (which corrupts Plex's musl loader) - Auto-discovery: broad structural patterns with string-anchored fallback (//feature) and relationship-based fallback (BITSET_REF within BS_INIT) - hook.cpp uses __has_include for generated patterns with hardcoded fallbacks - Custom wrapper.sh (no traffic_logger preload) - Vendored Freeloader source (github.com/authrequest/Freeloader, AGPL-3.0) - Removed stale plexmediaserver_crack.so binary - Supports Plex 1.43.3+ (verified against 1.43.2 and 1.43.3)
108 lines
4.4 KiB
Markdown
108 lines
4.4 KiB
Markdown
# Building & installing plexmediaserver_crack (Linux)
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## How this works (read this first)
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Plex Media Server ships and runs against its **own bundled musl libc + libgcompat**
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(`/usr/lib/plexmediaserver/lib/{libc.so,ld-musl-x86_64.so.1,libgcompat.so.0}`),
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**not** the host's glibc. Two consequences drive everything below:
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- **Build target must be musl.** A glibc-built `.so` fails to load into Plex: the
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loader can't relocate glibc-only symbols (`__isoc23_strtol`, `arc4random`,
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`*_chk`, `_dl_find_object`) and PMS exits 127. We cross-compile with **zig**
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(`-target x86_64-linux-musl`), which bundles musl + libc++ and statically links
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the C++ runtime, leaving only musl libc references that Plex's `libc.so` satisfies.
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- **Inject with `LD_PRELOAD`, never `patchelf`.** `patchelf --add-needed` rewrites
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the 22 MB BIND_NOW/PIE binary's program headers in a way musl's loader cannot
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tolerate, which **corrupts the executable** (instant SIGSEGV on start). `LD_PRELOAD`
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touches nothing on disk and is trivially reversible.
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The crack hooks `FeatureManager_apply_feature_list_xml` and forces all 14 entries
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of `g_feature_bitset_slots` on (the "Godmode" approach), enabling every feature
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including Plex Pass (feature code 92, slot 11).
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## Prerequisites
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A Linux environment (native or WSL). `build.sh` will download a pinned `zig`
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toolchain on first run, so you only need `curl` + `tar`/`xz` available (or `zig`
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already on `PATH`, or pass `ZIG=/path/to/zig`). No cmake/g++/glibc toolchain needed.
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## Build
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```bash
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bash build.sh
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```
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Output: `build/plexmediaserver_crack.so` (a musl shared object). The script runs an ABI
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sanity check and refuses to emit a `.so` that references any glibc-only symbol.
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It prints the install steps below on success.
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## Install (native systemd installs)
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The launcher `plex-crack-wrapper.sh` sets `LD_PRELOAD` **after** `/bin/sh` is
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already running and just before it `exec`s Plex, so only the (musl) Plex process
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is preloaded. The crack's constructor also calls `unsetenv("LD_PRELOAD")`, so the
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glibc `/bin/sh` helper children Plex spawns (Tuner Service, Script Host) are
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unaffected.
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```bash
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# 1. Place the artifacts on the Plex host:
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install -o plex -g plex -m644 build/plexmediaserver_crack.so /usr/lib/plexmediaserver/lib/
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install -m755 scripts/plex-crack-wrapper.sh /usr/local/bin/
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# 2. Drop-in that swaps ExecStart for the wrapper:
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mkdir -p /etc/systemd/system/plexmediaserver.service.d
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printf '[Service]\nExecStart=\nExecStart=/usr/local/bin/plex-crack-wrapper.sh\n' \
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> /etc/systemd/system/plexmediaserver.service.d/override.conf
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# 3. Apply:
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systemctl daemon-reload
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systemctl restart plexmediaserver
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```
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### Verify
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```bash
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systemctl is-active plexmediaserver # -> active
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curl -s -o /dev/null -w '%{http_code}\n' http://127.0.0.1:32400/identity # -> 200
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# Confirm the .so is mapped into the process:
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PID=$(systemctl show -p MainPID --value plexmediaserver)
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grep -F plexmediaserver_crack.so /proc/$PID/maps
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```
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`scripts/readbitset.py <pid>` (root) dumps the live feature bitset; all 14 slots should
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read `0xffffffffffffffff` when the hook is active.
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## Uninstall
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```bash
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rm -f /etc/systemd/system/plexmediaserver.service.d/override.conf
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rm -f /usr/lib/plexmediaserver/lib/plexmediaserver_crack.so /usr/local/bin/plex-crack-wrapper.sh
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systemctl daemon-reload && systemctl restart plexmediaserver
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```
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### Recovering a binary already corrupted by patchelf
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If a prior attempt ran `patchelf` against the Plex binary and PMS now SIGSEGVs on
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start, restore the pristine executable:
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```bash
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apt-get install --reinstall -y plexmediaserver
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# If the repo isn't configured, fetch the exact installed version and dpkg -i it:
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V=$(dpkg-query -W -f='${Version}' plexmediaserver)
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curl -fL -o /tmp/pms.deb "https://downloads.plex.tv/plex-media-server-new/$V/debian/plexmediaserver_${V}_amd64.deb"
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dpkg -i /tmp/pms.deb
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systemctl reset-failed plexmediaserver && systemctl restart plexmediaserver
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```
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## Notes
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- x86-64 Linux only.
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- "Godmode": enables ALL features regardless of GUID. The full feature UUID
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catalog is in `src/hook.cpp` (`kFeatureGuidCatalog`) for reference.
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- Signature patterns in `hook()` are version-specific; you may need to re-verify
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them after a PMS update.
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- For Docker (`plexinc/pms-docker`, `lscr.io/linuxserver/plex`), see
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[`DOCKER.md`](DOCKER.md) — same `LD_PRELOAD`-on-the-PMS-exec principle,
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but the s6 service plumbing is different per image.
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- For intro/credit detection: Settings -> Library -> Marker source -> "local detection only".
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